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Σάββατο 3 Φεβρουαρίου 2018

Predicted environmental concentration and fate of the top 10 most dispensed Australian prescription pharmaceuticals

Abstract

A basic environmental risk assessment was carried out for the top 10 dispensed pharmaceuticals in Melbourne, Australia, in contrast to the more commonly assessed measure of the most used drugs by physical mass. This allowed for the evaluation of compounds that had not previously been the subject of risk assessment. Estimations of the possible fate and behaviour of the target pharmaceuticals in sewage treatment plants were also made. The predicted removal rates of most drugs within standard sewage treatment were expected to be low, with the exception of the statins, which had high removal rates. Each pharmaceutical was predicted to be present in Melbourne wastewater at the nanogram per litre range or lower. All compounds were predicted to be of low toxicity risk, although it was not possible to model mixture effects. Atorvastatin and Irbesartan were also found to possess the potential to possibly bioaccumulate in the aquatic food chain but not to the extent that would require regulation or labelling.



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Aqueous aggregation and stability of graphene nanoplatelets, graphene oxide, and reduced graphene oxide in simulated natural environmental conditions: complex roles of surface and solution chemistry

Abstract

Graphene-family nanomaterials (GFNs) exhibit universal applications and consequently will inevitably enter aquatic systems. However, both the fate and behavior of GFNs in aquatic environments have not been completely explored at field relevant conditions. Herein, we have systematically investigated the aqueous aggregation and stability of graphene nanoplatelets (GNPs), graphene oxide (GO), and reduced graphene oxide (RGO) under varied solution chemistry parameters (pH, divalent cations, and dissolved organic carbon (DOC)) during 21 days of incubation in simulated natural environmental conditions. Results indicate that pH values from 6 to 9 had a notable impact on the aqueous behaviors of the three GFNs. Divalent cations (Ca2+ and Mg2+) at the concentrations of 2.5 and 10 mM remarkably increased the extent of aggregation of the three GFNs and resulted in severe sedimentation, independently of surface chemical functionalization. The presence of only DOC ranging from 0.5 to 2 mg C/L significantly elevated the dispersion stability of GNPs and RGO in a dose-dependent manner, whereas no effects were observed on GO. Furthermore, DOC at the studied concentrations and surface functionality were insufficient to counterbalance the impact of the divalent cations. Direct visual and in situ observations further supported the conclusions on the effects of divalent cations or/and DOC. These findings further underline that the environmental behaviors of GFNs are controlled by the complex interplay between water chemistry parameters and GFN surface properties.



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Organisms in wall ecosystems as biomonitors of metal deposition and bioavailability in urban environments

Abstract

Vegetated walls are common structures in urban environments, and aiming to test the hypothesis that the biogenic crusts and plant and animal communities inhabiting these vertical surfaces can be more reliable indicators of atmospheric metal deposition than plants or animals inhabiting urban soils, we analyzed the chemical composition of the wall crusts, moss cushions (Tortula muralis) and the shells, soft tissues and feces of the stonework snail Papillifera papillaris collected in three small towns in Tuscany (Central Italy). Crusts and mosses from the same stones or bricks indicated that Cd, Pb, and Zn are the main pollutants released by vehicular traffic, while Hg and Cu probably originate from other sources. The soft tissues of P. papillaris (purged of the gut contents) showed as well higher Cd, Pb, and Zn and lower Hg concentrations at more traffic-affected sites, while data from shells and feces suggested that this species probably ingests large amounts of Al, Cr, Fe, Mn, and Pb, and avoids eating mosses. Most lithophilic elements and Pb are scarcely absorbed in the snail digestive tract and soft tissues mainly accumulate Cd and essential elements such as Cu and Mn. This study definitively confirms the extraordinary Mn bioaccumulation in P. papillaris soft tissues and reports extraordinary Mn levels also in the shell. The shells also contain unusually high Cu, Fe, and Zn concentrations and this bioaccumulation likely remains after death, potentially providing a historical record of the snail exposure to metals over lifetime.



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Evaluating the evidence for motor-based interventions in developmental coordination disorder: A systematic review and meta-analysis

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Publication date: March 2018
Source:Research in Developmental Disabilities, Volume 74
Author(s): Bouwien Smits-Engelsman, Sabine Vinçon, Rainer Blank, Virgínia H. Quadrado, Helene Polatajko, Peter H. Wilson
BackgroundAs part of the process of creating an update of the clinical practice guidelines for developmental coordination disorder (DCD) (Blank, Smits-Engelsman, Polatajko, & Wilson, 2012), a systematic review of intervention studies, published since the last guidelines statement was conducted.AimThe aim of this study was to 1) systematically review the evidence published from January 2012 to February 2017 regarding the effectiveness of motor based interventions in individuals with DCD, 2) quantify treatment effects using a meta-analysis, 3) examine the available information on different aspects of delivery including use of group intervention, duration and frequency of therapy, and 4) identify gaps in the literature and make recommendations for future intervention research.MethodAn electronic search of 5 databases (PubMed, Embase, Pedro, Scopus and Cochrane) was conducted for studies that evaluated motor-based interventions to improve performance for individuals with DCD.ResultsThirty studies covering 25 datasets were included, 19 of which provided outcomes on standardized measures of motor performance. The overall effect size (Cohen's d) across intervention studies was large (1.06), but the range was wide: for 11 interventions, the observed effect was large (>0.80), in eight studies moderate (>0.50), and in five it was small or negligible (<0.50). Positive benefits were evident for activity-oriented approaches, body function-oriented combined with activities, active video games, and small group programs.ConclusionResults showed that activity-oriented and body function oriented interventions can have a positive effect on motor function and skills. However, given the varied methodological quality and the large confidence intervals of some studies, the results should be interpreted with caution.



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Enhancing the comprehension of visual metaphors in individuals with intellectual disability with or without down syndrome

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Publication date: March 2018
Source:Research in Developmental Disabilities, Volume 74
Author(s): Shlomit Shnitzer-Meirovich, Hefziba Lifshitz, Nira Mashal
This study is the first to investigate the effectiveness of deep and shallow intervention programs in the acquisition of visual metaphor comprehension in individuals with non-specific intellectual disability (NSID; aged 15–59, N = 53) or Down syndrome (DS; aged 15–52, N = 50). The deep intervention program was based on dynamic assessment model for enhancing analogical thinking. The shallow intervention program involves memorizing a metaphorical relationship between pairs of pictures. Visual metaphor comprehension was measured by the construction of a metaphorical connection between pairs of pictures. The results indicated that both etiology groups exhibited poor understanding of visual metaphors before the intervention. A significant improvement was observed in both interventions and both etiology groups, with greater improvement among individuals who underwent the deep processing. Moreover, the latter procedure led to greater generalization ability. The results also indicated that vocabulary contributed significantly to understanding unstudied metaphors and that participants with poorer linguistic abilities exhibited greater improvement in their metaphorical thinking. Thus, individuals with ID with or without DS are able to recruit the higher-order cognitive abilities required for visual metaphor comprehension.



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Sexuality issues and the voices of adults with intellectual disabilities: A systematic review of the literature

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Publication date: March 2018
Source:Research in Developmental Disabilities, Volume 74
Author(s): Michael Brown, Edward McCann
BackgroundThere is a growing and evolving research evidence base regarding sexuality issues and adults with intellectual disabilities. Individuals can face challenges, including the right to express their sexuality and to access necessary education and supports.AimsThis systematic review explores sexuality experiences, the views and opinions of adults with intellectual disabilities and highlights areas for future practice developments.Methods and proceduresA comprehensive search of relevant databases from January 2006 to December 2016 was carried out. Included studies had to address specific criteria including: peer reviewed papers, the use of appropriate research methods, and focused exclusively on the individual views and opinions of people with an intellectual disability. The search of relevant databases yielded 230 hits. Following the application of explicit inclusion and exclusion criteria, 23 papers were deemed suitable for the review.Outcomes and resultsThe data were analysed and key themes were identified that included: autonomy v's risk of harm, knowledge and sexuality, relationships and intimacy, self-determination and taking control, and encouragement and supports.Conclusions and implicationsAdults with intellectual disabilities need education and support to express their sexuality and to meet individual needs.



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Quality of life and habitual physical activity in children with cerebral palsy aged 5 years: A cross-sectional study

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Publication date: March 2018
Source:Research in Developmental Disabilities, Volume 74
Author(s): Piyapa Keawutan, Kristie L. Bell, Stina Oftedal, Peter S.W. Davies, Robert S. Ware, Roslyn N. Boyd
ObjectiveTo compare quality of life (QOL) according to ambulatory status and to investigate association with habitual physical activity (HPA) in children with cerebral palsy (CP) aged 5 years.MethodsFifty-eight participants were classified using Gross Motor Function Classification System (GMFCS) as level I = 33, II = 8, III = 6, IV = 3 and V = 8 and assessed for motor function using 66-item Gross Motor Function Measure (GMFM-66). Participants wore an ActiGraph® triaxial accelerometer for 3 days to measure HPA. Parents completed the parent proxy Cerebral Palsy Quality of Life questionnaire for Children (CP QOL-Child). Linear regression analyses were performed.ResultsAmbulant children with CP (GMFCS I–III) had better parent-reported QOL than non-ambulant children (GMFCS IV–V) in domains of feelings about functioning (mean difference (MD) = 20.0; 95% confidence interval (CI) = 11.7, 28.2), participation and physical health (MD = 14.5; 95%CI = 4.7, 24.4), and emotional well-being and self-esteem (MD = 12.5; 95%CI = 4.8, 20.1). HPA was not associated with QOL domains after controlling for motor function. GMFM scores accounted for 39% of variation for feelings about functioning domain (MD = 0.4; 95%CI = 0.2, 0.6).ConclusionsIn children with CP aged 5 years, HPA was not associated with parent-reported QOL. Gross motor function contributed to QOL domains of feelings about functioning.



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Auditory temporal perceptual learning and transfer in Chinese-speaking children with developmental dyslexia

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Publication date: March 2018
Source:Research in Developmental Disabilities, Volume 74
Author(s): Manli Zhang, Weiyi Xie, Yanzhi Xu, Xiangzhi Meng
Perceptual learning refers to the improvement of perceptual performance as a function of training. Recent studies found that auditory perceptual learning may improve phonological skills in individuals with developmental dyslexia in alphabetic writing system. However, whether auditory perceptual learning could also benefit the reading skills of those learning the Chinese logographic writing system is, as yet, unknown. The current study aimed to investigate the remediation effect of auditory temporal perceptual learning on Mandarin-speaking school children with developmental dyslexia. Thirty children with dyslexia were screened from a large pool of students in 3th-5th grades. They completed a series of pretests and then were assigned to either a non-training control group or a training group. The training group worked on a pure tone duration discrimination task for 7 sessions over 2 weeks with thirty minutes per session. Post-tests immediately after training and a follow-up test 2 months later were conducted. Analyses revealed a significant training effect in the training group relative to non-training group, as well as near transfer to the temporal interval discrimination task and far transfer to phonological awareness, character recognition and reading fluency. Importantly, the training effect and all the transfer effects were stable at the 2-month follow-up session. Further analyses found that a significant correlation between character recognition performance and learning rate mainly existed in the slow learning phase, the consolidation stage of perceptual learning, and this effect was modulated by an individuals' executive function. These findings indicate that adaptive auditory temporal perceptual learning can lead to learning and transfer effects on reading performance, and shed further light on the potential role of basic perceptual learning in the remediation and prevention of developmental dyslexia.



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Social validity in single-case research: A systematic literature review of prevalence and application

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Publication date: March 2018
Source:Research in Developmental Disabilities, Volume 74
Author(s): Melinda R. Snodgrass, Moon Y. Chung, Hedda Meadan, James W. Halle
BackgroundSingle-case research (SCR) has been a valuable methodology in special education research. Montrose Wolf (1978), an early pioneer in single-case methodology, coined the term "social validity" to refer to the social importance of the goals selected, the acceptability of procedures employed, and the effectiveness of the outcomes produced in applied investigations. Since 1978, many contributors to SCR have included social validity as a feature of their articles and several authors have examined the prevalence and role of social validity in SCR.Aim and methodsWe systematically reviewed all SCR published in six highly-ranked special education journals from 2005 to 2016 to establish the prevalence of social validity assessments and to evaluate their scientific rigor.ResultsWe found relatively low, but stable prevalence with only 28 publications addressing all three factors of the social validity construct (i.e., goals, procedures, outcomes). We conducted an in-depth analysis of the scientific rigor of these 28 publications.ConclusionsSocial validity remains an understudied construct in SCR, and the scientific rigor of social validity assessments is often lacking. Implications and future directions are discussed.



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Unravelling the role of fatty acid metabolism in cancer through the FOXO3-FOXM1 axis

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Publication date: 15 February 2018
Source:Molecular and Cellular Endocrinology, Volume 462, Part B
Author(s): Paula Saavedra-García, Katie Nichols, Zimam Mahmud, Lavender Yuen-Nam Fan, Eric W-F. Lam
Obesity and cachexia represent divergent states of nutritional and metabolic imbalance but both are intimately linked to cancer. There is an extensive overlap in their signalling pathways and molecular components involved such as fatty acids (FAs), which likely play a crucial role in cancer. Forkhead box (FOX) proteins are responsible of a wide range of transcriptional programmes during normal development, and the FOXO3-FOXM1 axis is associated with cancer initiation, progression and drug resistance. Free fatty acids (FFAs), FA synthesis and β-oxidation are associated with cancer development and progression. Meanwhile, insulin and some adipokines, that are up-regulated by FAs, are also involved in cancer development and poor prognosis. In this review, we discuss the role of FA metabolism in cancer and how FA metabolism integrates with the FOXO3-FOXM1 axis. These new insights may provide leads to better cancer diagnostics as well as strategies for tackling cancer development, progression and drug resistance.



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Editorial Board

Publication date: 15 February 2018
Source:Molecular and Cellular Endocrinology, Volume 462, Part B





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Sympathetic innervation is essential for metabolic homeostasis and pancreatic beta cell function in adult rats

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Publication date: 15 February 2018
Source:Molecular and Cellular Endocrinology, Volume 462, Part B
Author(s): Kelly V. Prates, Júlio C. de Oliveira, Ananda Malta, Camila C.I. Matiusso, Rosiane A. Miranda, Tatiane A. Ribeiro, Flávio A. Francisco, Claudinéia C.S. Franco, Veridiana M. Moreira, Vander S. Alves, Rosana Torrezan, Paulo C.F. Mathias, Luiz F. Barella
Obesity is associated with an imbalance in the activity of the autonomic nervous system (ANS), specifically in the organs involved in energy metabolism. The pancreatic islets are richly innervated by the ANS, which tunes the insulin release due to changes in energy demand. Therefore, changes in the sympathetic input that reach the pancreas can lead to metabolic dysfunctions. To evaluate the role of the sympathetic ends that innervate the pancreas, 60-day-old male Wistar rats were subjected to sympathectomy (SYM) or were sham-operated (SO). At 120 day-old SYM rats exhibited an increase in body weight, fat pads and metabolic dysfunctions. Decreases in the HOMA-IR and reductions in insulin release were observed both in vivo and in vitro. Furthermore, the SYM rats exhibited altered pancreatic islet function in both muscarinic and adrenergic assays and exhibited high protein expression of the alpha-2 adrenergic receptor (α2AR). Because α2AR has been linked to type 2 diabetes, these findings demonstrate the clinical implications of this study.



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Cluster-level statistical inference in fMRI datasets: The unexpected behavior of random fields in high dimensions

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Publication date: Available online 3 February 2018
Source:Magnetic Resonance Imaging
Author(s): Ravi Bansal, Bradley S. Peterson
Identifying regional effects of interest in MRI datasets usually entails testing a priori hypotheses across many thousands of brain voxels, requiring control for false positive findings in these multiple hypotheses testing. Recent studies have suggested that parametric statistical methods may have incorrectly modeled functional MRI data, thereby leading to higher false positive rates than their nominal rates. Nonparametric methods for statistical inference when conducting multiple statistical tests, in contrast, are thought to produce false positives at the nominal rate, which has thus led to the suggestion that previously reported studies should reanalyze their fMRI data using nonparametric tools.To understand better why parametric methods may yield excessive false positives, we assessed their performance when applied both to simulated datasets of 1D, 2D, and 3D Gaussian Random Fields (GRFs) and to 710 real-world, resting-state fMRI datasets. We showed that both the simulated 2D and 3D GRFs and the real-world data contain a small percentage (<6%) of very large clusters (on average 60 times larger than the average cluster size), which were not present in 1D GRFs. These unexpectedly large clusters were deemed statistically significant using parametric methods, leading to empirical familywise error rates (FWERs) as high as 65%: the high empirical FWERs were not a consequence of parametric methods failing to model spatial smoothness accurately, but rather of these very large clusters that are inherently present in smooth, high-dimensional random fields. In fact, when discounting these very large clusters, the empirical FWER for parametric methods was 3.24%. Furthermore, even an empirical FWER of 65% would yield on average less than one of those very large clusters in each brain-wide analysis. Nonparametric methods, in contrast, estimated distributions from those large clusters, and therefore, by construct rejected the large clusters as false positives at the nominal FWERs. Those rejected clusters were outlying values in the distribution of cluster size but cannot be distinguished from true positive findings without further analyses, including assessing whether fMRI signal in those regions correlates with other clinical, behavioral, or cognitive measures. Rejecting the large clusters, however, significantly reduced the statistical power of nonparametric methods in detecting true findings compared with parametric methods, which would have detected most true findings that are essential for making valid biological inferences in MRI data. Parametric analyses, in contrast, detected most true findings while generating relatively few false positives: on average, less than one of those very large clusters would be deemed a true finding in each brain-wide analysis. We therefore recommend the continued use of parametric methods that model nonstationary smoothness for cluster-level, familywise control of false positives, particularly when using a Cluster Defining Threshold of 2.5 or higher, and subsequently assessing rigorously the biological plausibility of the findings, even for large clusters. Finally, because nonparametric methods yielded a large reduction in statistical power to detect true positive findings, we conclude that the modest reduction in false positive findings that nonparametric analyses afford does not warrant a re-analysis of previously published fMRI studies using nonparametric techniques.



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Single-injection ex ovo transplantation method for broad spinal cord engraftment of human pluripotent stem cell-derived motor neurons

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Publication date: Available online 3 February 2018
Source:Journal of Neuroscience Methods
Author(s): Maria C. Estevez-Silva, Akshitha Sreeram, Stephanie Cuskey, Nikolai Fedorchak, Nisha Iyer, Randolph S. Ashton
BackgroundTransplantation of human pluripotent stem cell (hPSC)-derived neurons into chick embryos is an established preliminary assay to evaluate engraftment potential. Yet, with recent advances in deriving diverse human neuronal subtypes, optimizing and standardizing such transplantation methodology for specific subtypes at their correlated anatomical sites is still required.New methodWe determined the optimal stage of hPSC-derived motor neuron (hMN) differentiation for ex ovo transplantation, and developed a single injection protocol that implants hMNs throughout the spinal cord enabling broad regional engraftment possibilities.ResultsA single injection into the neural tube lumen yielded a 100% chick embryo survival and successful transplantation rate with MN engraftment observed from the rostral cervical through caudal lumbar spinal cord. Transplantation of HB9+/ChAT hMN precursors yielded the greatest amount of engraftment compared to Pax6+/Nkx6.1+/Olig2+ progenitors or mature HB9+/ChAT+ hMNs.Comparison with existing method(s)Our single injection hMN transplant method is the first to standardize the optimal hMN phenotype for chick embryo transplantation, provide a rubric for engraftment quantification, and enable broad engraftment throughout the spinal cord with a single surgical intervention.ConclusionTransplantation of HB9+/ChAT hMN precursors into chick embryos of Hamburger Hamilton (HH) stages 15-18 using a single luminal injection confers a high probability of embryo survival and cell engraftment in diverse regions throughout the spinal cord.



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In vivo two-photon imaging of motoneurons and adjacent glia in the ventral spinal cord

Publication date: Available online 3 February 2018
Source:Journal of Neuroscience Methods
Author(s): Luciana Politti Cartarozzi, Phillip Rieder, Xianshu Bai, Anja Scheller, Alexandre Leite Rodrigues de Oliveira, Frank Kirchhoff
BackgroundInteractions between motoneurons and glial cells are pivotal to regulate and maintain functional states and synaptic connectivity in the spinal cord. In vivo two-photon imaging of the nervous system provided novel and unexpected knowledge about structural and physiological changes in the grey matter of the forebrain and in the dorsal white matter of the spinal cord.New methodHere, we describe a novel experimental strategy to investigate the spinal grey matter, i.e. the ventral horn motoneurons and their adjacent glial cells by employing in vivo two-photon laser-scanning microscopy (2P-LSM) in anesthetized transgenic mice.ResultsAfter retrograde tracer labeling in transgenic mice with cell-specific expression of fluorescent proteins and surgical exposure of the lumbar intumescence groups of motoneurons could be visualized deeply localized in the ventral horn. In this region, morphological responses of microglial cells to ATP could be recorded for an hour. In addition, using in mice with expression of GCaMP3 in astrocytes, physiological Ca2+ signals could be recorded after local noradrenalin application.Comparison with existing methodsPrevious in vivo imaging protocols were restricted to the superficial dorsal white matter or upper layers of the dorsal horn. Here, we modified a multi-step procedure originally established for a root-crush injury. We adapted it to simultaneously visualize motoneurons and adjacent glial cells in living animals.ConclusionA modified surgery approach is presented to visualize fluorescently labelled motoneurons and glial cells at a depth of more than 200 μm in the grey matter ventral horn of the mouse spinal cord.

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Targeted muscle reinnervation: advances and opportunities

It is with interest, and some concern, that we read the recent letter from Messrs Nikkhah et al. (1). Targeted muscle reinnervation (TMR) is a surgical development for the rehabilitation community with enormous potential to improve the quality of life for amputees. However, their letter fails to clarify exactly what TMR is, and how it can benefit amputees. There are two aspects to TMR. Kuiken's first aim was to improve the control of a myoelectric prostheses and secondly to strive for "intuitive" manipulation of a prosthesis (2,3).

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Overexpression of YAP1 in EGFR mutant lung adenocarcinoma prior to tyrosine kinase inhibitor therapy is associated with poor survival

Publication date: Available online 3 February 2018
Source:Pathology - Research and Practice
Author(s): Soon Auck Hong, Si-Hyong Jang, Mee-Hye Oh, Sung Joon Kim, Jin-Hyung Kang, Sook-Hee Hong
EGFR tyrosine kinase inhibitor (EGFR TKI) is approved as first-line treatment for advanced-stage EGFR mutant lung adenocarcinoma (LADC). Yes-associated protein 1 (YAP1), a main effector of the Hippo pathway, is associated with adverse prognosis and disruption of EGFR TKI modulation of non-small cell lung cancer. In this study, we demonstrated a prognostic role of YAP1 in EGFR mutant LADC and efficacy of EGFR TKI therapy. A total of 63 patients, including 41 with paired lung cancer specimens before and after EGFR TKI therapy and 22 with non-paired lung cancer specimens prior to EGFR TKI, were enrolled for examination. Expression of YAP1 protein was evaluated using immunohistochemistry. Fifteen paired cases (36.6%) with high nuclear YAP1 expression were detected in the pre-EGFR TKI LADC group and 21 paired cases (52.5%) after treatment with EGFR TKI. Nuclear YAP1 expression was significantly upregulated after EGFR TKI therapy (P = 0.002). Fifteen paired cases with high nuclear YAP1 expression before EGFR TKI LADCs showed poorer overall survival (OS) (P = 0.023) and progression-free survival (PFS) (P = 0.041). Among the 63 patients under study, those with high nuclear YAP1 expression before EGFR TKI showed shorter OS (P = 0.038) and PFS (P < 0.001). High nuclear YAP1 expression in cases with acquired EGFR exon 20 T790 M mutant LADCs showed poorer OS (P < 0.001). We demonstrated that YAP1 burden before clinical application of EGFR TKI plays a crucial role in prognosis of EGFR mutant LADC treated using EGFR TKI.



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The split hypoglossal nerve versus the cross-face nerve graft to supply the free functional muscle transfer for facial reanimation: a comparative study

Long-standing cases of facial paralysis are currently treated with free functional muscle transfer. Several nerves are mentioned in the literature to supply the free muscle transfer. The aim of this study is to compare the split hypoglossal nerve and the cross-face nerve graft to supply the free functional muscle transfer in facial reanimation.Of 94 patients with long-standing, unilateral facial palsy, 49 were treated using the latissimus dorsi muscle supplied by the split hypoglossal nerve, and 45 patients were treated using the healthy contralateral buccal branch of the facial nerve.

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Mapping population-based structural connectomes

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Zhengwu Zhang, Maxime Descoteaux, Jingwen Zhang, Gabriel Girard, Maxime Chamberland, David Dunson, Anuj Srivastava, Hongtu Zhu
Advances in understanding the structural connectomes of human brain require improved approaches for the construction, comparison and integration of high-dimensional whole-brain tractography data from a large number of individuals. This article develops a population-based structural connectome (PSC) mapping framework to address these challenges. PSC simultaneously characterizes a large number of white matter bundles within and across different subjects by registering different subjects' brains based on coarse cortical parcellations, compressing the bundles of each connection, and extracting novel connection weights. A robust tractography algorithm and streamline post-processing techniques, including dilation of gray matter regions, streamline cutting, and outlier streamline removal are applied to improve the robustness of the extracted structural connectomes. The developed PSC framework can be used to reproducibly extract binary networks, weighted networks and streamline-based brain connectomes. We apply the PSC to Human Connectome Project data to illustrate its application in characterizing normal variations and heritability of structural connectomes in healthy subjects.



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Age-related differences in BOLD modulation to cognitive control costs in a multitasking paradigm: Global switch, local switch, and compatibility-switch costs

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Kaoru Nashiro, Shuo Qin, Margaret A. O'Connell, Chandramallika Basak
It is well documented that older adults recruit additional brain regions compared to those recruited by younger adults while performing a wide variety of cognitive tasks. However, it is unclear how such age-related over-recruitment interacts with different types of cognitive control, and whether this over-recruitment is compensatory. To test this, we used a multitasking paradigm, which allowed us to examine age-related over-activation associated with three types of cognitive costs (i.e., global switch, local switch, compatibility-switch costs). We found age-related impairments in global switch cost (GSC), evidenced by slower response times for maintaining and coordinating two tasks vs. performing only one task. However, no age-related declines were observed in either local switch cost (LSC), a cognitive cost associated with switching between the two tasks while maintaining two task loads, or compatibility-switch cost (CSC), a cognitive cost associated with incompatible vs. compatible stimulus-response mappings across the two tasks. The fMRI analyses allowed for identification of distinct cognitive cost-sensitive brain regions associated with GSC and LSC. In fronto-parietal GSC and LSC regions, older adults' increased activations were associated with poorer performance (greater costs), whereas a reverse relationship was observed in younger adults. Older adults also recruited additional fronto-parietal brain regions outside the cognitive cost-sensitive areas, which was associated with poorer performance or no behavioral benefits. Our results suggest that older adults exhibit a combination of inefficient activation within cognitive cost-sensitive regions, specifically the GSC and LSC regions, and non-compensatory over-recruitment in age-sensitive regions. Age-related declines in global switching, compared to local switching, was observed earlier in old age at both neural and behavioral levels.



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Neural source dynamics of brain responses to continuous stimuli: Speech processing from acoustics to comprehension

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Christian Brodbeck, Alessandro Presacco, Jonathan Z. Simon
Human experience often involves continuous sensory information that unfolds over time. This is true in particular for speech comprehension, where continuous acoustic signals are processed over seconds or even minutes. We show that brain responses to such continuous stimuli can be investigated in detail, for magnetoencephalography (MEG) data, by combining linear kernel estimation with minimum norm source localization. Previous research has shown that the requirement to average data over many trials can be overcome by modeling the brain response as a linear convolution of the stimulus and a kernel, or response function, and estimating a kernel that predicts the response from the stimulus. However, such analysis has been typically restricted to sensor space. Here we demonstrate that this analysis can also be performed in neural source space. We first computed distributed minimum norm current source estimates for continuous MEG recordings, and then computed response functions for the current estimate at each source element, using the boosting algorithm with cross-validation. Permutation tests can then assess the significance of individual predictor variables, as well as features of the corresponding spatio-temporal response functions. We demonstrate the viability of this technique by computing spatio-temporal response functions for speech stimuli, using predictor variables reflecting acoustic, lexical and semantic processing. Results indicate that processes related to comprehension of continuous speech can be differentiated anatomically as well as temporally: acoustic information engaged auditory cortex at short latencies, followed by responses over the central sulcus and inferior frontal gyrus, possibly related to somatosensory/motor cortex involvement in speech perception; lexical frequency was associated with a left-lateralized response in auditory cortex and subsequent bilateral frontal activity; and semantic composition was associated with bilateral temporal and frontal brain activity. We conclude that this technique can be used to study the neural processing of continuous stimuli in time and anatomical space with the millisecond temporal resolution of MEG. This suggests new avenues for analyzing neural processing of naturalistic stimuli, without the necessity of averaging over artificially short or truncated stimuli.



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Simultaneous estimation of population receptive field and hemodynamic parameters from single point BOLD responses using Metropolis-Hastings sampling

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Stanisław Adaszewski, David Slater, Lester Melie-Garcia, Bogdan Draganski, Piotr Bogorodzki
We introduce a new approach to Bayesian pRF model estimation using Markov Chain Monte Carlo (MCMC) sampling for simultaneous estimation of pRF and hemodynamic parameters. To obtain high performance on commonly accessible hardware we present a novel heuristic consisting of interpolation between precomputed responses for predetermined stimuli and a large cross-section of receptive field parameters. We investigate the validity of the proposed approach with respect to MCMC convergence, tuning and biases. We compare different combinations of pRF - Compressive Spatial Summation (CSS), Dumoulin-Wandell (DW) and hemodynamic (5-parameter and 3-parameter Balloon-Windkessel) models within our framework with and without the usage of the new heuristic. We evaluate estimation consistency and log probability across models. We perform as well a comparison of one model with and without lookup table within the RStan framework using its No-U-Turn Sampler. We present accelerated computation of whole-ROI parameters for one subject. Finally, we discuss risks and limitations associated with the usage of the new heuristic as well as the means of resolving them. We found that the new algorithm is a valid sampling approach to joint pRF/hemodynamic parameter estimation and that it exhibits very high performance.



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Development of subcortical volumes across adolescence in males and females: A multisample study of longitudinal changes

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Megan M. Herting, Cory Johnson, Kathryn L. Mills, Nandita Vijayakumar, Meg Dennison, Chang Liu, Anne-Lise Goddings, Ronald E. Dahl, Elizabeth R. Sowell, Sarah Whittle, Nicholas B. Allen, Christian K. Tamnes
The developmental patterns of subcortical brain volumes in males and females observed in previous studies have been inconsistent. To help resolve these discrepancies, we examined developmental trajectories using three independent longitudinal samples of participants in the age-span of 8–22 years (total 216 participants and 467 scans). These datasets, including Pittsburgh (PIT; University of Pittsburgh, USA), NeuroCognitive Development (NCD; University of Oslo, Norway), and Orygen Adolescent Development Study (OADS; The University of Melbourne, Australia), span three countries and were analyzed together and in parallel using mixed-effects modeling with both generalized additive models and general linear models. For all regions and across all samples, males were found to have significantly larger volumes as compared to females, and significant sex differences were seen in age trajectories over time. However, direct comparison of sample trajectories and sex differences identified within samples were not consistent. The trajectories for the amygdala, putamen, and nucleus accumbens were most consistent between the three samples. Our results suggest that even after using similar preprocessing and analytic techniques, additional factors, such as image acquisition or sample composition may contribute to some of the discrepancies in sex specific patterns in subcortical brain changes across adolescence, and highlight region-specific variations in congruency of developmental trajectories.



http://ift.tt/2FGMtGW

Decoding the auditory brain with canonical component analysis

Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Alain de Cheveigné, Daniel E. Wong, Giovanni M. Di Liberto, Jens Hjortkjær, Malcolm Slaney, Edmund Lalor
The relation between a stimulus and the evoked brain response can shed light on perceptual processes within the brain. Signals derived from this relation can also be harnessed to control external devices for Brain Computer Interface (BCI) applications. While the classic event-related potential (ERP) is appropriate for isolated stimuli, more sophisticated "decoding" strategies are needed to address continuous stimuli such as speech, music or environmental sounds. Here we describe an approach based on Canonical Correlation Analysis (CCA) that finds the optimal transform to apply to both the stimulus and the response to reveal correlations between the two. Compared to prior methods based on forward or backward models for stimulus-response mapping, CCA finds significantly higher correlation scores, thus providing increased sensitivity to relatively small effects, and supports classifier schemes that yield higher classification scores. CCA strips the brain response of variance unrelated to the stimulus, and the stimulus representation of variance that does not affect the response, and thus improves observations of the relation between stimulus and response.



http://ift.tt/2Ef3zPa

Neuroanatomical morphometric characterization of sex differences in youth using statistical learning

Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Farshid Sepehrband, Kirsten M. Lynch, Ryan P. Cabeen, Clio Gonzalez-Zacarias, Lu Zhao, Mike D'Arcy, Carl Kesselman, Megan M. Herting, Ivo D. Dinov, Arthur W. Toga, Kristi A. Clark
Exploring neuroanatomical sex differences using a multivariate statistical learning approach can yield insights that cannot be derived with univariate analysis. While gross differences in total brain volume are well-established, uncovering the more subtle, regional sex-related differences in neuroanatomy requires a multivariate approach that can accurately model spatial complexity as well as the interactions between neuroanatomical features. Here, we developed a multivariate statistical learning model using a support vector machine (SVM) classifier to predict sex from MRI-derived regional neuroanatomical features from a single-site study of 967 healthy youth from the Philadelphia Neurodevelopmental Cohort (PNC). Then, we validated the multivariate model on an independent dataset of 682 healthy youth from the multi-site Pediatric Imaging, Neurocognition and Genetics (PING) cohort study. The trained model exhibited an 83% cross-validated prediction accuracy, and correctly predicted the sex of 77% of the subjects from the independent multi-site dataset. Results showed that cortical thickness of the middle occipital lobes and the angular gyri are major predictors of sex. Results also demonstrated the inferential benefits of going beyond classical regression approaches to capture the interactions among brain features in order to better characterize sex differences in male and female youths. We also identified specific cortical morphological measures and parcellation techniques, such as cortical thickness as derived from the Destrieux atlas, that are better able to discriminate between males and females in comparison to other brain atlases (Desikan-Killiany, Brodmann and subcortical atlases).

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Direct electrophysiological evidence for the maintenance of retrieval orientations and the role of cognitive control

Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Jane E. Herron
Retrieval orientations are memory states that bias retrieval towards specific memory contents. Many neuroimaging studies have examined the influence of retrieval orientations on stimulus processing, but very little direct evidence exists regarding the ongoing maintenance of orientations themselves. Participants completed two memory tasks with different retrieval goals. ERPs were time-locked to a pre-stimulus fixation asterisk and contrasted according to retrieval goals. Pre-stimulus ERPs elicited during the two retrieval tasks diverged at frontal electrode sites. These differences onset early and were sustained throughout the fixation-stimulus interval. The functional and spatiotemporal characteristics of this ERP effect comprise the first direct electrophysiological evidence of the ongoing maintenance of retrieval orientations throughout a task. Moreover, this effect was eliminated in participants who performed a stroop task prior to the memory tests, indicating that reserves of cognitive control play an important role in the maintenance of retrieval orientations throughout memory tasks.

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White matter microstructural variability mediates the relation between obesity and cognition in healthy adults

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Rui Zhang, Frauke Beyer, Leonie Lampe, Tobias Luck, Steffi G. Riedel-Heller, Markus Loeffler, Matthias L. Schroeter, Michael Stumvoll, Arno Villringer, A. Veronica Witte
Obesity has been linked with structural and functional brain changes. However, the impact of obesity on brain and cognition in aging remains debatable, especially for white matter. We therefore aimed to determine the effects of obesity on white matter microstructure and potential implications for cognition in a well-characterized large cohort of healthy adults. In total, 1255 participants (50% females, 19–80 years, BMI 16.8–50.2 kg/m2) with diffusion-weighted magnetic resonance imaging at 3T were analysed. Tract-based spatial statistics (TBSS) probed whether body mass index (BMI) and waist-to-hip ratio (WHR) were related to fractional anisotropy (FA). We conducted partial correlations and mediation analyses to explore whether obesity or regional FA were related to cognitive performance. Analyses were adjusted for demographic, genetic, and obesity-associated confounders. Results showed that higher BMI and higher WHR were associated with lower FA in multiple white matter tracts (p < 0.05, FWE-corrected). Mediation analyses provided evidence for indirect negative effects of higher BMI and higher WHR on executive functions and processing speed through lower FA in fiber tracts connecting (pre)frontal, visual, and associative areas (indirect paths, |ß| ≥ 0.01; 99% |CI| > 0). This large cross-sectional study showed that obesity is correlated with lower FA in multiple white matter tracts in otherwise healthy adults, independent of confounders. Moreover, although effect sizes were small, mediation results indicated that visceral obesity was linked to poorer executive functions and lower processing speed through lower FA in callosal and associative fiber tracts. Longitudinal studies are needed to support this hypothesis.



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Studying emotion theories through connectivity analysis: Evidence from generalized psychophysiological interactions and graph theory

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Yun-An Huang, Jan Jastorff, Jan Van den Stock, Laura Van de Vliet, Patrick Dupont, Mathieu Vandenbulcke
Psychological construction models of emotion state that emotions are variable concepts constructed by fundamental psychological processes, whereas according to basic emotion theory, emotions cannot be divided into more fundamental units and each basic emotion is represented by a unique and innate neural circuitry. In a previous study, we found evidence for the psychological construction account by showing that several brain regions were commonly activated when perceiving different emotions (i.e. a general emotion network). Moreover, this set of brain regions included areas associated with core affect, conceptualization and executive control, as predicted by psychological construction models. Here we investigate directed functional brain connectivity in the same dataset to address two questions: 1) is there a common pathway within the general emotion network for the perception of different emotions and 2) if so, does this common pathway contain information to distinguish between different emotions? We used generalized psychophysiological interactions and information flow indices to examine the connectivity within the general emotion network. The results revealed a general emotion pathway that connects neural nodes involved in core affect, conceptualization, language and executive control. Perception of different emotions could not be accurately classified based on the connectivity patterns from the nodes of the general emotion pathway. Successful classification was achieved when connections outside the general emotion pathway were included. We propose that the general emotion pathway functions as a common pathway within the general emotion network and is involved in shared basic psychological processes across emotions. However, additional connections within the general emotion network are required to classify different emotions, consistent with a constructionist account.



http://ift.tt/2EgGHib

Quantifying axonal responses in patient-specific models of subthalamic deep brain stimulation

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Kabilar Gunalan, Bryan Howell, Cameron C. McIntyre
Medical imaging has played a major role in defining the general anatomical targets for deep brain stimulation (DBS) therapies. However, specifics on the underlying brain circuitry that is directly modulated by DBS electric fields remain relatively undefined. Detailed biophysical modeling of DBS provides an approach to quantify the theoretical responses to stimulation at the cellular level, and has established a key role for axonal activation in the therapeutic mechanisms of DBS. Estimates of DBS-induced axonal activation can then be coupled with advances in defining the structural connectome of the human brain to provide insight into the modulated brain circuitry and possible correlations with clinical outcomes. These pathway-activation models (PAMs) represent powerful tools for DBS research, but the theoretical predictions are highly dependent upon the underlying assumptions of the particular modeling strategy used to create the PAM. In general, three types of PAMs are used to estimate activation: 1) field-cable (FC) models, 2) driving force (DF) models, and 3) volume of tissue activated (VTA) models. FC models represent the "gold standard" for analysis but at the cost of extreme technical demands and computational resources. Consequently, DF and VTA PAMs, derived from simplified FC models, are typically used in clinical research studies, but the relative accuracy of these implementations is unknown. Therefore, we performed a head-to-head comparison of the different PAMs, specifically evaluating DBS of three different axonal pathways in the subthalamic region. The DF PAM was markedly more accurate than the VTA PAMs, but none of these simplified models were able to match the results of the patient-specific FC PAM across all pathways and combinations of stimulus parameters. These results highlight the limitations of using simplified predictors to estimate axonal stimulation and emphasize the need for novel algorithms that are both biophysically realistic and computationally simple.



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Decoding intentions of self and others from fMRI activity patterns

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Sam J. Gilbert, Hoki Fung
Previous studies using multi-voxel pattern analysis have decoded the content of participants' delayed intentions from patterns of fMRI data. Here we investigate whether this technique can be used to decode not only participants' own intentions, but also their representation of the intentions held by other people. In other words: if Sam is thinking about Hoki, can we decode the content of Hoki's intention by scanning Sam's brain? We additionally distinguished two components of intentions: action-plans versus goals, and included novel control analyses that allowed us to distinguish intending an outcome from simply expecting it to occur or simulating its consequences. Regions of frontal, parietal, and occipital cortex contained patterns from which it was possible to decode intentions of both self and other. Furthermore, crossclasification between self and other was possible, suggesting overlap between the two. Control analyses suggested that these results reflected visuo-spatial processes by which intentions were generated in our paradigm, rather than anything special about intentions per se. There was no evidence for any representation of intentions as mental states distinct from visuospatial processes involved in generating their content and/or simulating their outcomes. These findings suggest that the brain activity patterns decoded in intention-decoding fMRI studies may reflect domain-general processes rather than being intention-specific.



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Insight and inference for DVARS

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Publication date: 15 May 2018
Source:NeuroImage, Volume 172
Author(s): Soroosh Afyouni, Thomas E. Nichols
Estimates of functional connectivity using resting state functional Magnetic Resonance Imaging (rs-fMRI) are acutely sensitive to artifacts and large scale nuisance variation. As a result much effort is dedicated to preprocessing rs-fMRI data and using diagnostic measures to identify bad scans. One such diagnostic measure is DVARS, the spatial root mean square of the data after temporal differencing. A limitation of DVARS however is the lack of concrete interpretation of the absolute values of DVARS, and finding a threshold to distinguish bad scans from good. In this work we describe a sum of squares decomposition of the entire 4D dataset that shows DVARS to be just one of three sources of variation we refer to as D-var (closely linked to DVARS), S-var and E-var. D-var and S-var partition the sum of squares at adjacent time points, while E-var accounts for edge effects; each can be used to make spatial and temporal summary diagnostic measures. Extending the partitioning to global (and non-global) signal leads to a rs-fMRI DSE table, which decomposes the total and global variability into fast (D-var), slow (S-var) and edge (E-var) components. We find expected values for each component under nominal models, showing how D-var (and thus DVARS) scales with overall variability and is diminished by temporal autocorrelation. Finally we propose a null sampling distribution for DVARS-squared and robust methods to estimate this null model, allowing computation of DVARS p-values. We propose that these diagnostic time series, images, p-values and DSE table will provide a succinct summary of the quality of a rs-fMRI dataset that will support comparisons of datasets over preprocessing steps and between subjects.



http://ift.tt/2FKfSA7

Combination of nano-material enrichment and dead-end filtration for uniform and rapid sample preparation in matrix-assisted laser desorption/ionization mass spectrometry

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Zengnan Wu, Mashooq Khan, Sifeng Mao, Ling Lin, Jin-Ming Lin
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a fast analysis tool for the detection of a wide range of analytes. However, heterogeneous distribution of matrix/analyte cocrystal, variation in signal intensity and poor experimental reproducibility at different locations of the same spot means difficulty in quantitative analysis. In this work, carbon nanotubes (CNTs) were employed as adsorbent for analyte cum matrix on a conductive porous membrane as a novel mass target plate. The sample pretreatment step was achieved by enrichment and dead-end filtration and dried by a solid-liquid separation. This approach enables the homogeneous distribution of analyte in the matrix, good shot-to-shot reproducibility in signals and quantitative detection of peptide and protein at different concentrations with correlation coefficient (R2) of 0.9920 and 0.9909, respectively. The simple preparation of sample in a short time, uniform distribution of analyte, easy quantitative detection, and high reproducibility makes this technique useful and may diversify the application of MALDI-MS for quantitative detection of a variety of proteins.

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Multifunctional Au NPs-polydopamine-polyvinylidene fluoride membrane chips as probe for enrichment and rapid detection of organic contaminants

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Saihua Wang, Hongyun Niu, Yaqi Cai, Dong Cao
High-throughput and rapid detection of hazardous compounds in complicated samples is essential for the solution of environmental problems. We have prepared a "pH-paper-like" chip which can rapidly "indicate" the occurrence of organic contaminants just through dipping the chip in water samples for short time followed by fast analysis with surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The chips are composed of polyvinylidene fluoride membrane (PVDFM), polydopamine (PDA) film and Au nanoparticles (Au NPs), which are layer-by-layer assembled according to the adhesion, self-polymerization and reduction property of dopamine. In the Au NPs loaded polydopamine-polyvinylidene fluoride membrane (Au NPs-PDA-PVDFM) chips, PVDFM combined with PDA film are responsible for the enrichment of organic analyte through hydrophobic interactions and π–π stacking; Au NPs serve as effective SALDI matrix for the rapid detection of target analyte. After dipping into water solution for minutes, the Au-PDA-PVDFM chips with enriched organic analytes can be detected directly with SALDI-TOF MS. The good solid-phase extraction performance of the PDA-PVDFM components, remarkable matrix effect of the loaded AuNPs, and sensitivity of the SALDI-TOF MS technique ensure excellent sensitivity and reproducibility for the quantification of trace levels of organic contaminants in environmental water samples.

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http://ift.tt/2nzgrFY

Thermo/pH dual-stimuli-responsive drug delivery for chemo-/photothermal therapy monitored by cell imaging

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Yang Shu, Rusheng Song, Anqi Zheng, Jingli Huang, Mingli Chen, Jianhua Wang
A thermo/pH dual-stimuli-responsive drug delivery system (DDS) based on polymer coated mesoporous silica nanostructures (MSNs) is developed for facilitating chemotherapy and photothermal therapy. Thermo/pH-responsive polymer, poly((N-isopropylacrylamide, NIPAM)-co-methacrylic acid, MA), is grafted onto MSNs by in situ polymerization, followed by loading a chemotherapeutic drug (doxorubicin hydrochloride, DOX) and a near-infrared-absorbing phototherapeutic agent (indocyanine green, ICG) to construct the intelligent drug delivery system, shortly as DOX-ICG-MSN@p(NIPAM-co-MA). At NIR irradiation, the photothermal conversion capability of ICG raises the temperature of the DDS and opens the gatekeeper by shrinkage of the copolymer p(NIPAM-co-MA), which triggers controlled release of DOX at an elevated temperature. On the other hand, drug release is also realized at pH 5.3, a characteristic pH value in cancer cell microenvironment, at which it not only causes the shrinkage of the pH-sensitive polymeric moiety of methacrylic acid in MSN@p(NIPAM-co-MA) but also deteriorates electrostatic interaction of DOX molecules in the mesoporous channel by protonation of silanols. In addition, ICG further ensures photothermal therapy (PTT) and photodynamic therapy (PDT). The cytotoxicity assay of HeLa cells shows obvious synergistic effect by demonstrating that the combined use of DOX and ICG is more effective in killing HeLa cells than free DOX and ICG. The endocytosis of the drug is monitored by cell imaging.

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Competitive fluorescent pseudo-immunoassay exploiting molecularly imprinted polymers for the detection of biogenic amines in fish matrix

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Leena Mattsson, Jingjing Xu, Claudia Preininger, Bernadette Tse Sum Bui, Karsten Haupt
We developed a competitive fluorescent molecularly imprinted polymer (MIP) assay to detect biogenic amines in fish samples. MIPs synthesized by precipitation polymerization using histamine as template were used in a batch binding assay analogous to competitive fluoroimmunoassays. Introducing a complex sample matrix, such as fish extract, into the assay changes the environment and the binding conditions, therefore the importance of the sample preparation is extensively discussed. Several extraction and purification methods for fish were comprehensively studied, and an optimal clean-up procedure for fish samples using liquid-liquid extraction was developed. The feasibility of the competitive MIP assay was shown in the purified fish extract over a broad histamine range (1 − 430µM). The MIP had the highest affinity towards histamine, but recognized also the structurally similar biogenic amines tyramine and tryptamine, as well as spermine and spermidine, providing simultaneous analysis and assessment of the total amount of biogenic amines.

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Polydopamine-based functional composite particles for tumor cell targeting and dual-mode cellular imaging

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Yalei Zhou, Jie Zhou, Feng Wang, Haifeng Yang
Particles which bear tumor cell targeting and multimode imaging capabilities are promising in tumor diagnosis and cancer therapy. A simple and versatile method to fabricate gold/polydopamine-Methylene Blue@Bovine Serum Albumin–glutaraldehyde–Transferrin composite particles (Au/PDA-MB@BSA-GA-Tf NPs) for tumor cell targeting and fluorescence (FL) / surface-enhanced Raman scattering (SERS) dual-modal imaging were reported in this work. Polydopamine (PDA) spheres played an important role in gold ion reduction, gold nanoparticle (Au NPs) binding and methylene blue (MB) adsorption, MB were employed as both fluorescence label and Raman reporter. In addition, glutaraldehyde (GA) crosslinked bovine serum albumin (BSA) in the outer layer of Au/PDA-MB nanoparticles can prevent MB from dissociation and leakage. The composite nanoparticles were further conjugated with transferrin (Tf) to target transferrin receptor (TfR)-overexpressed cancer cells. The targeting ability as well as the intracellular location of the probe was investigated through SERS mapping and fluorescence imaging. Their excellent biocompatibility was demonstrated by low cytotoxicity against breast cancer cell (4T1 cell).

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Adsorption behavior of thorium on N,N,N′,N′-tetraoctyldiglycolamide (TODGA) impregnated graphene aerogel

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Mumei Chen, Zheng Li, Yiyun Geng, Haogui Zhao, Shuhua He, Qingnuan Li, Lan Zhang
As a kind of three-dimensional graphene architecture material with superhydrophobic, low density, high specific surface area and porosity, graphene aerogel (GA) can be used to immobilize extractant to constitute the solvent impregnated adsorbent. In this paper, the N,N,N′,N′-tetraoctyldiglycolamide impregnated graphene aerogel ( GA-TODGA) was prepared to remove the thorium from aqueous solution. It is found that the adsorption of thorium on GA-TODGA is strongly dependent on the concentration of TODGA in GA and HNO3 in aqueous solution. Compared with other solvent impregnated adsorbents, the adsorption capacity of GA-TODGA is much higher due to the high immobilization capacity of GA for TODGA. Furthermore, the GA-TODGA also possesses excellent stability and reusability, ensuring the application potential of using GA-TODGA in large scale.

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http://ift.tt/2nzRiLo

Vis-NIR spectrometric determination of Brix and sucrose in sugar production samples using kernel partial least squares with interval selection based on the successive projections algorithm

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Valber Elias de Almeida, Adriano de Araújo Gomes, David Douglas de Sousa Fernandes, Héctor Casimiro Goicoechea, Roberto Kawakami Harrop Galvão, Mario Cesar Ugulino Araújo
This paper proposes a new variable selection method for nonlinear multivariate calibration, combining the Successive Projections Algorithm for interval selection (iSPA) with the Kernel Partial Least Squares (Kernel-PLS) modelling technique. The proposed iSPA-Kernel-PLS algorithm is employed in a case study involving a Vis-NIR spectrometric dataset with complex nonlinear features. The analytical problem consists of determining Brix and sucrose content in samples from a sugar production system, on the basis of transflectance spectra. As compared to full-spectrum Kernel-PLS, the iSPA-Kernel-PLS models involve a smaller number of variables and display statistically significant superiority in terms of accuracy and/or bias in the predictions.

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http://ift.tt/2BSjI7M

A new tool for the evaluation of the analytical procedure: Green Analytical Procedure Index

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): J. Płotka-Wasylka
A new means for assessing analytical protocols relating to green analytical chemistry attributes has been developed. The new tool, called GAPI (Green Analytical Procedure Index), evaluates the green character of an entire analytical methodology, from sample collection to final determination, and was created using such tools as the National Environmental Methods Index (NEMI) or Analytical Eco-Scale to provide not only general but also qualitative information. In GAPI, a specific symbol with five pentagrams can be used to evaluate and quantify the environmental impact involved in each step of an analytical methodology, mainly from green through yellow to red depicting low, medium to high impact, respectively. The proposed tool was used to evaluate analytical procedures applied in the determination of biogenic amines in wine samples, and polycyclic aromatic hydrocarbon determination by EPA methods. GAPI tool not only provides an immediately perceptible perspective to the user/reader but also offers exhaustive information on evaluated procedures.

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http://ift.tt/2nzOq13

Rapid determination of hydrophilic phenols in olive oil by vortex-assisted reversed-phase dispersive liquid-liquid microextraction and screen-printed carbon electrodes

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Elena Fernández, Lorena Vidal, Antonio Canals
A novel approach is presented to determine hydrophilic phenols in olive oil samples, employing vortex-assisted reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) for sample preparation and screen-printed carbon electrodes for voltammetric analysis. The oxidation of oleuropein, hydroxytyrosol, caffeic acid, ferulic acid and tyrosol was investigated, being caffeic acid and tyrosol selected for quantification. A matrix-matching calibration using sunflower oil as analyte-free sample diluted with hexane was employed to compensate matrix effects. Samples were analyzed under optimized RP-DLLME conditions, i.e., extractant phase, 1M HCl; extractant volume, 100µL; extraction time, 2min; centrifugation time, 10min; centrifugation speed, 4000rpm. The working range showed a good linearity between 0.075 and 2.5mgL−1 (r = 0.998, N = 7) for caffeic acid, and between 0.075 and 3mgL−1 (r = 0.999, N = 8) for tyrosol. The methodological limit of detection was empirically established at 0.022mgL−1 for both analytes, which is significantly lower than average contents found in olive oil samples. The repeatability was evaluated at two different spiking levels (i.e., 0.5mgL−1 and 2mgL−1) and coefficients of variation ranged from 8% to 11% (n = 5). The applicability of the proposed method was tested in olive oil samples of different quality (i.e., refined olive oil, virgin olive oil and extra virgin olive oil). Relative recoveries varied between 83% and 108% showing negligible matrix effects. Finally, fifteen samples were analyzed by the proposed method and a high correlation with the traditional Folin-Ciocalteu spectrophotometric method was obtained. Thereafter, the concentrations of the fifteen oil samples were employed as input variables in linear discriminant analysis in order to distinguish between olive oils of different quality.

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Development and application of molecularly imprinted polymer – Mn-doped ZnS quantum dot fluorescent optosensing for cocaine screening in oral fluid and serum

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): María Pilar Chantada–Vázquez, Carolina de–Becerra–Sánchez, Alba Fernández–del–Río, Juan Sánchez–González, Ana María Bermejo, Pilar Bermejo–Barrera, Antonio Moreda–Piñeiro
A molecularly imprinted polymer – Mn-doped ZnS quantum dot-based fluorescence probe for cocaine abuse screening has been prepared and applied to complex samples such as serum and oral fluid. The fluorescent sensing material was prepared by anchoring a selective MIP for COC on the surface of polyethylene glycol (PEG) modified Mn-doped ZnS quantum dots (QDs). Simple and low cost methods have thus been optimized for assessing cocaine abuse in serum and oral fluid by monitoring fluorescence quenching when cocaine (COC) is present (optimized operating conditions with 1.5mL of 200mgL-1 MIP-coated QDs solution, pH 5.5, and 15min before fluorescence scanning). The matrix effect was found to be important when analyzing oral fluid and serum, and several strategies based on centrifugation for oral fluid and solid phase extraction (SPE) for serum were explored. Two analytical methods were developed for oral fluid. The first one (direct method) requires a centrifugation step (6°C, 4000rpm, 20min) to avoid the matrix effect, and allows for cocaine determination by using an aqueous calibration (1:20 dilution). The second method was developed for oral fluid sampled by Salivette devices, and also requires a further centrifugation (6°C, 4000rpm, 20min) of the recovered oral fluid. This method, however, requires the standard addition technique (1:20 dilution) because of the existence of the matrix effect. Regarding serum samples, a direct method (serum dilution) was not possible, and an SPE procedure was needed to avoid the matrix effect (use of aqueous calibration). The limits of detection and quantification when using the Salivette method were 0.035mgL-1and 0.117mgL-1, respectively; whereas, 0.015mgL-1 (LOD) and 0.050mgL-1 (LOQ) were obtained for serum.

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Speciation of inorganic arsenic(III) and arsenic(V) by a facile dual-cloud point extraction coupled with inductively plasma-optical emission spectrometry

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Shengping Wen, Xiashi Zhu
A simple and efficient method using dual-cloud point extraction (dual-CPE) coupled with inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for the speciation of inorganic arsenic [As(III) and As(V)]. In first step of dual-CPE, As(III) formed a hydrophobic complex with ammonium pyrrolidine dithiocarbamate (As-APDC), and was subsequently entrapped by the Triton X-114 surfactant-rich phase at pH 5.0, whereas As(V) remained in the bulk supernatant. The surfactant-rich phase containing the As(III)-APDC complex was treated with a 2.0molL−1 of nitric acid, and As(III) was back extracted into the aqueous phase at the second cloud point extraction stage before ICP-OES detection. The As(V) concentration was calculated by subtracting the concentration of As(III) from the total inorganic arsenic concentration after reducing As(V) to As(III) by thiourea. Different factors affecting the extraction of As(III) were investigated in detail. Under the optimum conditions, the detection limit for As(III) was 0.72ngmL−1 along with the relative standard deviation of 3.5% (C = 10.0ngmL−1, n = 5). The calibration curve was linear in the range of 2.0–50.0ngmL−1. This method was validated against the certified reference material (GSBZ 50004-88), and applied for the speciation of inorganic As(III) and As(V) in the spiked snow water sample.

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The effect of loading carbon nanotubes onto chitosan films on electrochemical dopamine sensing in the presence of biological interference

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Sudheesh K. Shukla, Avia Lavon, Offir Shmulevich, Hadar Ben-Yoav
In vivo monitoring of the neurotransmitter dopamine can potentially improve the diagnosis of neurological disorders and elucidate their underlying biochemical mechanisms. While electrochemical sensors can detect unlabeled dopamine molecules, their sensing performance is dramatically reduced by electrochemical currents generated by other, interfering molecules (e.g., uric acid) in the biological environment. To overcome this caveat, the surface of the sensor is often modified with electrocatalytic materials, which are encapsulated inside a polymeric film; however, the effect of the encapsulating film on the sensing performance of the electrode has not been systematically studied. This study characterizes the effect of loading carbon nanotubes (CNTs) onto a chitosan film on the electrochemical sensing performance of dopamine in the presence of uric acid. Higher CNT loading increases the diffusion and electron transfer rate coefficients of the sensor and, in the presence of uric acid, provides better sensitivity (3.00µALµmol−1 for 1.75% CNT loading, vs 0.01µALµmol−1 for 1% loading) but a poorer limit-of-detection (2.00µmolL−1vs 1.00, respectively), as reported here for the first time. These findings can help optimize the sensitivity and the limit-of-detection of electrochemical sensors in complex biofluids to enable an in vivo monitoring of dopamine and other redox-active molecules.

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Preparation of core-shell structured magnetic covalent organic framework nanocomposites for magnetic solid-phase extraction of bisphenols from human serum sample

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Lei Chen, Yanting He, Zhixian Lei, Chenling Gao, Qing Xie, Ping Tong, Zian Lin
Core-shell structured magnetic covalent organic framework (Fe3O4@COF) nanocomposites were synthesized via a facile approach at room temperature and explored as an absorbent for magnetic solid-phase extraction (MSPE) of bisphenols (BPs) from human serum sample. The as-prepared Fe3O4@COF nanocomposites with core-shell structure possessed high specific surface area (181.36m2/g), uniform mesoporous size (~ 3.6nm), high saturation magnetization (42.7emu/g), and excellent thermal and chemical stability, rendering it as an ideal adsorbent with high adsorption efficiency and size selectivity. The experimental parameters influencing extraction efficiency, including adsorbent dosage, extraction time, pH and ion strength, desorption solvent and time, were investigated in detail. Taking these advantages together, a simple, fast, effective and sensitive method that MPSE followed by HPLC-MS, was proposed to detect five BPs, which exhibited good linearity (r > 0.9982) within the concentration ranges of 0.1–50μg/L. Moreover, the low detection limits (1.0–78.1ng/L), signal-to-noise ratio (S/N = 3), the high enrichment factors (56–95 fold), and good recoveries (93.0–107.8%) with relative standard deviations (RSDs) less than 3.4% for inter-day and 6.9% for intra-day were achieved. The developed method was also successfully applied to the analysis of trace BPs in human serum sample, which demonstrated the most promising potential of the Fe3O4@COF nanocomposites as good adsorbent in sample pretreatment.

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Testing of nylon 6 nanofibers with different surface densities as sorbents for solid phase extraction and their selectivity comparison with commercial sorbent

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Martina Háková, Hedvika Raabová, Lucie Chocholoušová Havlíková, Petr Chocholouš, Jiří Chvojka, Dalibor Šatínský
Nylon 6 nanofibers were tested for their ability to serve as a sorbent for solid phase extraction (SPE). The regular nanostructure providing a great sorption area and amidic functionality should lead to the assumption that nylon 6 nanofibers could be used as a novel sorbent with great potential for sample pre-treatment. However, due to the substantial differences between classical particle sorbents used for solid phase extraction and nanofibers, it is necessary to evaluate this novel approach. This article describes three types of laboratory fabricated nylon 6 nanofibers with different surface density (5.04gm−2, 3.90gm−2 and 0.75gm−2) and corresponding surface areas for solid phase extraction of several groups of compounds with different structural and physicochemical properties (parabens, steroids, flavonoids and pesticides). The nanofibers were created by needleless electrospinning. Extraction columns were manually packed in classic 1- or 3-mL plastic syringe cartridges with 26–30mg of nanofibers and the column bed was sealed with polypropylene frits. The SPE procedure followed a typical five-step protocol and the collected eluates were analyzed by HPLC with UV detection. Extraction recovery was used as a parameter to evaluate the behavior of the analytes within the SPE process. Under this set condition, the recovery of the SPE process ranged from 23.1% to 125.8%. SPE showed good repeatability (0.58–11.87% RSD) and inter-day reproducibility (3.86–9.79% RSD). The achieved results were compared with SPE using a classic particle sorbent column. Good mechanical and chemical stability of nanofibers was proved. Scanning electron microscope was used for the evaluation of morphological changes in nanostructure. Nylon 6 nanofibers proved being a cost-effective sorbent for repeated use in SPE. Nylon 6 nanofibers have great potential in miniaturized SPE enabling users to overcome troubles with high back-pressure.

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Adsorption studies of cadmium onto magnetic Fe3O4@FePO4 and its preconcentration with detection by electrothermal atomic absorption spectrometry

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Xiaoxing Zhang, Changle Sun, Li Zhang, Hui Liu, Binxia Cao, Libo Liu, Weimin Gong
Superparamagnetic Fe3O4@FePO4 nanoparticles with core shell structure were prepared by coating iron phosphate on the surface of Fe3O4 nanoparticles by liquid phase deposition method. The prepared materials were characterized by vibrating sample magnetometer, scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectrometer, nano Zetasizer, X-ray photoelectron spectroscopy and Raman spectrometer. These characterization methods were also used to describe the adsorption mechanism. The obtained composite material was used for the adsorption of a heavy metal element, cadmium. Its unique magnetic properties are favorable for rapid separation and preconcentration of trace cadmium from aqueous solutions. About 100% sorption was achieved at pH 7 for 1mL, 10μgL−1 of cadmium. Batch adsorption experiments show that the adsorption fits Langmuir model, and a maximum adsorption capacity 13.51mgg−1 is derived for Cd(II). The retained Cd(II) could be readily recovered by 200μL of HNO3 (0.01molL−1). The cadmium in the eluate is quantified with detection by electrothermal atomic absorption spectrometry (ETAAS). A sample volume of 2000μL creates an enrichment factor of 10.3, along with a detection limit of 0.021µgL−1 (3σ, n=7) and a RSD of 1.3% (0.1µgL−1, n=7) within a linear calibration range of 0.05–0.5µgL−1. The practical applicability of this procedure was validated by analyzing cadmium contents in a certified reference material (GBW08608) and two environmental water samples.

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Capillary zone electrophoresis method to assay tipranavir capsules and identification of oxidation product and organic impurity by quadrupole-time of flight mass spectrometry

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Matheus Wagner Lago, Mariane Lago Friedrich, Gabrielle Dineck Iop, Thiago Belarmino de Souza, Paola de Azevedo Mello, Andréa Inês Horn Adams
Tipranavir (TPV) is one of the most recently developed protease inhibitors (PI) and it is specially recommended for treatment-experienced patients who are resistant to other PI drugs. In this work, a simple and friendly environmental CZE stability-indicating method to assay TPV capsules was developed and two TPV organic impurities were identified by high resolution mass spectrometry (HRMS). The optimized analytical conditions were: background electrolyte composed of sodium borate 50mM, pH 9.0 and 5% of methanol; voltage + 28kV; hydrodynamic injection of 5s (100mbar), detection wavelength 240nm, at 25°C. The separation was achieved in a fused silica capillary with 50µm × 40cm (inner diameter × effective length), using furosemide as internal standard. All the validation parameters were met and the method was specific, even in the presence of degradation products and impurities. Oxidation was indicated as the main degradation pathway among those evaluated in this study (acidic, alkaline, thermal, photolytic and oxidative) and it showed a second order degradation kinetic, under the conditions used in this study. The main oxidation product and an organic impurity detected in the standard were characterized by Q-TOF, and both of them correspond to oxidation products of TPV.

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Electrodialytic extraction of anionic pharmaceutical compounds from a single drop of whole blood using a supported liquid membrane

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Yurika Imoto, Hiroka Nishiyama, Yukihide Nakamura, Shin-Ichi Ohira, Kei Toda
A method to introduce target analytes to a chromatograph from a single drop of whole blood was investigated for minimally invasive monitoring of anionic pharmaceuticals. In this work, salicylate and loxoprofen were examined as organic anions. A micro ion extractor (MIE) has been developed for extraction of inorganic trace anions from whole blood, but this device is not suitable for extraction of pharmaceuticals. In the present study, we improved and optimized the MIE device for organic anion extraction. Various supported liquid membranes were evaluated for use as the ion transfer membrane, with each membrane placed between a droplet sample (donor) and an acceptor solution. A supported liquid membrane of porous polypropylene impregnated with 1-butanol was selected. In addition, the methods for electric field creation and electrode contact were examined to improve the characteristics of the MIE device. The current and extraction time were also optimized. With the optimized method, salicylate and loxoprofen were successfully extracted from a single drop of whole blood. Changes in the concentrations of these pharmaceuticals in blood over time were monitored after administration. As only 25μL of whole blood was required for analysis, repeat measurements could be conducted to monitor changes in the concentrations. This MIE will be useful for monitoring pharmaceutical concentrations in blood.

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Aqueous biphasic systems formed by deep eutectic solvent and new-type salts for the high-performance extraction of pigments

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Hongmei Zhang, Yuzhi Wang, Yigang Zhou, Jing Chen, Xiaoxiao Wei, Panli Xu
Deep eutectic solvent (DES) composed of polypropylene glycol 400 (PPG 400) and tetrabutylammonium bromide (TBAB) was combined with a series of new-type salts such as quaternary ammonium salts, amino acid and polyols to form Aqueous Biphasic Systems (ABSs). Phase-forming ability of the salts was investigated firstly. The results showed that polyols had a relatively weak power to produce phases within studied scopes. And the shorter of carbon chain length of salts, the easier to obtain phase-splitting. Then partitioning of three pigments in PPG 400/betaine-based ABSs was addressed to investigate the effect of pigments' hydrophobicity on extraction efficiency. It was found that an increase in hydrophobicity contributed to the migration of pigments in the DES-rich phase. On the other hand, with a decline in phase-forming ability of salts, the extraction efficiency of the whole systems started to go down gradually. Based on the results, selective separation experiment was conducted successfully in the PPG 400/betaine-based systems, including more than 93.00% Sudan Ⅲ in the top phase and about 80.00% sunset yellow FCF/amaranth in the bottom phase. Additionally, ABSs constructed by DES/betaine for partitioning amaranth were further utilized to explore the performances of influence factors and back extraction. It can be concluded that after the optimization above 98.00% amaranth was transferred into the top phase. And 67.98% amaranth can be transferred into the bottom phase in back-extraction experiment. At last, dynamic light scattering (DLS) and transmission electron microscope (TEM) were applied to probe into extraction mechanism. The results demonstrated that hydrophobicity played an important role in the separation process of pigments. Through combining with new-type DES, this work was devoted to introducing plentiful salts as novel compositions of ABSs and providing an eco-friendly extraction way for partitioning pigments, which boosted development of ABSs in the monitoring food safety field.

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An interferometric imaging biosensor using weighted spectrum analysis to confirm DNA monolayer films with attogram sensitivity

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Rongxin Fu, Qi Li, Ruliang Wang, Ning Xue, Xue Lin, Ya Su, Kai Jiang, Xiangyu Jin, Rongzan Lin, Wupeng Gan, Ying Lu, Guoliang Huang
Interferometric imaging biosensors are powerful and convenient tools for confirming the existence of DNA monolayer films on silicon microarray platforms. However, their accuracy and sensitivity need further improvement because DNA molecules contribute to an inconspicuous interferometric signal both in thickness and size. Such weaknesses result in poor performance of these biosensors for low DNA content analyses and point mutation tests. In this paper, an interferometric imaging biosensor with weighted spectrum analysis is presented to confirm DNA monolayer films. The interferometric signal of DNA molecules can be extracted and then quantitative detection results for DNA microarrays can be reconstructed. With the proposed strategy, the relative error of thickness detection was reduced from 88.94% to merely 4.15%. The mass sensitivity per unit area of the proposed biosensor reached 20 attograms (ag). Therefore, the sample consumption per unit area of the target DNA content was only 62.5 zeptomoles (zm), with the volume of 0.25 picolitres (pL). Compared with the fluorescence resonance energy transfer (FRET), the measurement veracity of the interferometric imaging biosensor with weighted spectrum analysis is free to the changes in spotting concentration and DNA length. The detection range was more than 1µm. Moreover, single nucleotide mismatch could be pointed out combined with specific DNA ligation. A mutation experiment for lung cancer detection proved the high selectivity and accurate analysis capability of the presented biosensor.

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A rhodamine-based fluorescent probe for colorimetric and fluorescence lighting-up determination of toxic thiophenols in environmental water and living cells

Publication date: 1 May 2018
Source:Talanta, Volume 181
Author(s): Juanjuan Wu, Zhuo Ye, Feng Wu, Hongying Wang, Lintao Zeng, Guang-Ming Bao
Thiophenols are a class of highly toxic environmental pollutant, hence it is very necessary to monitor thiophenols in environment and living cells with an efficient and reliable method. Herein, a novel fluorescent probe for thiophenols has been developed, which exhibited a colorimetric and fluorescence turn-on dual response towards thiophenols with good selectivity and fast response. The sensing mechanism for thiophenols was attributed to nucleophilic substitution reaction, which was confirmed by HPLC. The probe exhibited good recovery (from 90% to 107%) and low limit of detection for thiophenols (37nM) in industrial wastewater. Moreover, the probe has been successfully employed to visualize thiophenol in living cells. Therefore, the fluorescent probe has good capability for monitoring thiophenols in environmental samples and biological systems.

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Biochar alleviates the toxicity of imidacloprid and silver nanoparticles (AgNPs) to Enchytraeus albidus (Oligochaeta)

Abstract

The present study investigated the use of biochar for the alleviation of the toxic effects of a nanosilver colloidal dispersion and a chloronicotinyl insecticide. The survival and reproduction of the potworm Enchytraeus albidus were assessed after exposure to imidacloprid and silver nanoparticles (AgNPs). E. albidus was exposed to 0, 25, 50, 100, 200, and 400 mg imidacloprid/kg and 0, 5, 25, 125, and 625 mg Ag/kg for 21 days in 10% biochar amended and non-biochar amended OECD artificial soil. In both exposure substrates, the effects of imidacloprid on survival were significant in the two highest treatments (p < 0.01). No biochar effect was observed as survival was statistically similar in both soils after exposure to imidacloprid. In the case of AgNPs, significant mortality was only observed in the highest AgNP treatments in both the amended and non-amended soils (p < 0.05). Nevertheless, statistically greater survival occurred in the biochar-amended treatment (p < 0.05). Reproduction results showed a more pronounced biochar effect with an EC50 = 22.27 mg imidacloprid/kg in the non-amended soil and a higher EC50 = 46.23 mg imidacloprid/kg in the biochar-amended soil. This indicated a 2-fold decrease in imidacloprid toxicity due to biochar amendment. A similar observation was made in the case of AgNPs where a reproduction EC50 = 166.70 mg Ag/kg soil in the non-amended soil increased to an EC50 > 625 mg Ag/kg soil (the highest AgNP treatment) in the amended soil. This indicated at least a 3.7-fold decrease in AgNPs toxicity due to biochar amendment. Although more studies may be needed to optimize the easing effects of biochar on the toxicity of these chemicals, the present results show that biochar could be useful for the alleviation of the toxic effects of imidacloprid and silver nanoparticles in the soil.



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Toxicity comparison of the shoreline cleaners Accell Clean® and PES-51® in two life stages of the grass shrimp, Palaemonetes pugio

Abstract

Oil spills are a significant source of coastal pollution. Shoreline cleaners, used to remove oil from surfaces during spill response and remediation, may also act as toxins. Adult and larval grass shrimp, Palaemonetes pugio, were tested for lethal and sublethal impacts from two shoreline cleaners, Accell Clean SWA® and PES-51®, alone and in combination with crude oil using Chemically Enhanced Water Accommodated Fractions (CEWAFs). Median lethal toxicity values determined for the individual cleaners were similar. However, when tested in mixture with oil as CEWAFs, Accell Clean SWA resulted in greater hydrocarbon concentrations in the water column and greater toxicity than PES-51. Increased glutathione levels were observed for adult shrimp exposed to Accell Clean SWA, and glutathione was elevated in shrimp exposed to both CEWAFs. Larval shrimp development was delayed after exposure to both CEWAFs. These findings may have implications for managing and mitigating oil spills.



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Obesity surgery and risk of colorectal and other obesity-related cancers: An English population-based cohort study

Publication date: April 2018
Source:Cancer Epidemiology, Volume 53
Author(s): Ariadni Aravani, Amy Downing, James D. Thomas, Jesper Lagergren, Eva J.A. Morris, Mark A. Hull
BackgroundThe association between obesity surgery (OS) and cancer risk remains unclear. We investigated this association across the English National Health Service. A population-based Swedish study has previously suggested that OS may increase the risk of developing colorectal cancer (CRC).MethodsA retrospective observational study of individuals who underwent OS (surgery cohort) or diagnosed with obesity, but had no OS (no-surgery cohort) (1997–2013) were identified using Hospital Episode Statistics. Subsequent diagnosis of CRC, breast, endometrial, kidney and lung cancer, as well as time 'at risk', were determined by linkage to National Cancer Registration & Analysis Service and Office of National Statistics data, respectively. Standardised incidence ratios (SIR) in relation to OS were calculated.Results1 002 607 obese patients were identified, of whom 3.9% (n = 39 747) underwent OS. In the no-surgery obese population, 3 237 developed CRC (SIR 1.12 [95% CI 1.08–1.16]). In those who underwent OS, 43 developed CRC (SIR 1.26 [95% CI 0.92–1.71]). The OS cohort demonstrated decreased breast cancer risk (SIR 0.76 [95% CI 0.62–0.92]), unlike the no surgery cohort (SIR 1.08 [95% CI 1.04–1.11]). Increased risk of endometrial and kidney cancer was observed in surgery and no-surgery cohorts.ConclusionsCRC risk is increased in individuals diagnosed as obese. Prior obesity surgery was not associated with an increased CRC risk. However, the OS population was small, with limited follow-up. Risk of breast cancer after OS is reduced compared with the obese no-surgery population, while the risk of endometrial and kidney cancers remained elevated after OS.



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The placental immune response is dysregulated developmentally vitamin D deficient rats: Relevance to Autism

Publication date: Available online 3 February 2018
Source:The Journal of Steroid Biochemistry and Molecular Biology
Author(s): Asad Ali, Xiaoying Cui, Suzanne Alexander, Darryl Eyles
Emerging evidence suggests that maternal or developmental vitamin D (DVD) deficiency is a risk factor for Autism Spectrum Disorders. A well-established association has also been found between gestational infection and increased incidence of autism. Placenta mediates the maternal immune response in respect to the foetus. The placenta is also a major source of vitamin D and locally produced vitamin D is an essential regulator of immune function during pregnancy. Here we investigate the effects of DVD-deficiency on baseline placental immune status and in response to the well-known viral and bacterial immune activating agents polyriboinosinic-polyribocytidylic acid (poly(I:C) and lipopolysaccharide (LPS). We show DVD-deficiency does not affect baseline inflammatory cytokines in placenta. However, when challenged with poly(I:C) but not LPS, DVD-deficient placentas from male foetuses had higher production of IL-6 and 1L-1β compared to control placentas. This suggests the developing DVD-deficient male foetus may be particularly vulnerable to maternal viral exposures. This in turn may have adverse implications for the developing male brain. In conclusion, a dysregulated placental immune response may provide a plausible mechanism for both the epidemiological links between DVD-deficiency and increased male incidence of developmental conditions such as autism.



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Juvenile hormone and sesquiterpenoids in arthropods: Biosynthesis, signaling, and role of MicroRNA

Publication date: Available online 3 February 2018
Source:The Journal of Steroid Biochemistry and Molecular Biology
Author(s): Zhe Qu, William G. Bendena, Stephen S. Tobe, Jerome H.L. Hui
Arthropod molting and reproduction are precisely controlled by the levels of sesquiterpenoids, a class of C15 hormones derived from three isoprene units. The two major functional arthropod sesquiterpenoids are juvenile hormone (JH) and methyl farnesoate (MF). In hemimetabolous insects (such as the aphids, bugs, and cockroaches) and holometabolous insects (such as beetles, bees, butterflies, and flies), dramatic decrease in the titers of JH and/or MF promote metamorphosis from larvae to adults either directly or through an intermediate pupal stage, respectively. JH is absent in crustaceans (lobster, shrimp, crab) and other arthropods (chelicerates such as ticks, mites, spiders, scorpions and myriapods such as millipede and centipedes). In some crustaceans, molting and reproduction is dependent on changing levels of MF. The regulation of sesquiterpenoid production is thus crucial in the life cycle of arthropods. Dynamic and complex mechanisms have evolved to regulate sesquiterpenoid production. Noncoding RNAs such as the microRNAs are primary regulators. This article provides an overview of microRNAs that are known to regulate sesquiterpenoid production in arthropods.



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Editorial Board

Publication date: February 2018
Source:Biomedicine & Pharmacotherapy, Volume 98





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Reliability of two pragmatic tools for assessing text neck

Publication date: Available online 2 February 2018
Source:Journal of Bodywork and Movement Therapies
Author(s): Gerson Moreira Damasceno, Arthur Sá Ferreira, Leandro Alberto Calazans Nogueira, Felipe José Jandre Reis, Rodrigo Wagner Lara, Ney Meziat-Filho
BackgroundThere is a hypothesis that the growing use of mobile phones in an inappropriate posture to text and read (text neck) could be a reason for the increasing prevalence of neck pain in the past decade. Before testing if there is an association between text neck and neck pain, it is necessary to develop reliable pragmatic tools appropriate to epidemiological studies.ObjectivesThe primary aim of this study was to assess the reliability of the self-perception of text neck, as well as the reliability of physiotherapists' classification of the text neck.MethodsThe convenience sample was composed of 113 high school students between 18 and 21 years old from a cross-sectional study. As their self-perceived posture, participants had to choose in a questionnaire one of four neck postures of a person texting on a mobile phone. The physiotherapists classified lateral photographs taken with the participants texting on a mobile phone in their habitual posture as 1 (normal), 2 (acceptable), 3 (inappropriate), and 4 (excessively inappropriate).ResultsThe results showed that the test–retest reliability of the self-perception was substantial (kappa = 0.73, 95% CI 0.54 to 0.86). The reliability of the physiotherapists' responses, according to the photographic analysis considering the three raters, was moderate (kappa = 0.5, 95% CI 0.39 to 0.61). Seventy-six percent of the participants with appropriate posture in the photographic analysis self-reported an inappropriate posture.ConclusionThis study showed that the self-perception of the neck posture during mobile phone texting is reliable over time and that the physiotherapists' classification based on photographic analysis was acceptable for epidemiological studies. Participants had a tendency to report that the posture was worse than it actually was in the photographic analysis performed by the physiotherapists.



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