Interoceptive signals impact visual processing: Cardiac modulation of visual body perception

Publication date: September 2017
Source:NeuroImage, Volume 158
Author(s): Roberta Ronchi, Fosco Bernasconi, Christian Pfeiffer, Javier Bello-Ruiz, Mariia Kaliuzhna, Olaf Blanke
Multisensory perception research has largely focused on exteroceptive signals, but recent evidence has revealed the integration of interoceptive signals with exteroceptive information. Such research revealed that heartbeat signals affect sensory (e.g., visual) processing: however, it is unknown how they impact the perception of body images. Here we linked our participants' heartbeat to visual stimuli and investigated the spatio-temporal brain dynamics of cardio-visual stimulation on the processing of human body images. We recorded visual evoked potentials with 64-channel electroencephalography while showing a body or a scrambled-body (control) that appeared at the frequency of the on-line recorded participants' heartbeat or not (not-synchronous, control). Extending earlier studies, we found a body-independent effect, with cardiac signals enhancing visual processing during two time periods (77–130 ms and 145–246 ms). Within the second (later) time-window we detected a second effect characterised by enhanced activity in parietal, temporo-occipital, inferior frontal, and right basal ganglia-insula regions, but only when non-scrambled body images were flashed synchronously with the heartbeat (208–224 ms). In conclusion, our results highlight the role of interoceptive information for the visual processing of human body pictures within a network integrating cardio-visual signals of relevance for perceptual and cognitive aspects of visual body processing.



http://ift.tt/2tdwOs8

How to improve parameter estimates in GLM-based fMRI data analysis: cross-validated Bayesian model averaging

Publication date: September 2017
Source:NeuroImage, Volume 158
Author(s): Joram Soch, Achim Pascal Meyer, John-Dylan Haynes, Carsten Allefeld
In functional magnetic resonance imaging (fMRI), model quality of general linear models (GLMs) for first-level analysis is rarely assessed. In recent work (Soch et al., 2016: "How to avoid mismodelling in GLM-based fMRI data analysis: cross-validated Bayesian model selection", NeuroImage, vol. 141, pp. 469–489; http://ift.tt/2tdeWxw), we have introduced cross-validated Bayesian model selection (cvBMS) to infer the best model for a group of subjects and use it to guide second-level analysis. While this is the optimal approach given that the same GLM has to be used for all subjects, there is a much more efficient procedure when model selection only addresses nuisance variables and regressors of interest are included in all candidate models. In this work, we propose cross-validated Bayesian model averaging (cvBMA) to improve parameter estimates for these regressors of interest by combining information from all models using their posterior probabilities. This is particularly useful as different models can lead to different conclusions regarding experimental effects and the most complex model is not necessarily the best choice. We find that cvBMS can prevent not detecting established effects and that cvBMA can be more sensitive to experimental effects than just using even the best model in each subject or the model which is best in a group of subjects.



http://ift.tt/2tHotA8

Active avoidance and attentive freezing in the face of approaching threat

Publication date: September 2017
Source:NeuroImage, Volume 158
Author(s): Julia Wendt, Andreas Löw, Mathias Weymar, Martin Lotze, Alfons O. Hamm
Defensive behaviors in animals and humans vary dynamically with increasing proximity of a threat and depending upon the behavioral repertoire at hand. The current study investigated physiological and behavioral adjustments and associated brain activation when participants were exposed to dynamically approaching threat that was either inevitable or could be avoided by motor action. When the approaching threat was inevitable, attentive freezing was observed as indicated by fear bradycardia, startle potentiation, and a dynamic increase in activation of the anterior insula and the periaqueductal grey. In preparation for active avoidance a switch in defensive behavior was observed characterized by startle inhibition and heart rate acceleration along with potentiated activation of the amygdala and the periaqueductal grey. Importantly, the modulation of defensive behavior according to threat imminence and the behavioral option at hand was associated with activity changes in the ventromedial prefrontal cortex. These findings improve our understanding of brain mechanisms guiding human behavior during approaching threat depending on available resources.



http://ift.tt/2tHGi2j

Improved tractography using asymmetric fibre orientation distributions

Publication date: September 2017
Source:NeuroImage, Volume 158
Author(s): Matteo Bastiani, Michiel Cottaar, Krikor Dikranian, Aurobrata Ghosh, Hui Zhang, Daniel C. Alexander, Timothy E. Behrens, Saad Jbabdi, Stamatios N. Sotiropoulos
Diffusion MRI allows us to make inferences on the structural organisation of the brain by mapping water diffusion to white matter microstructure. However, such a mapping is generally ill-defined; for instance, diffusion measurements are antipodally symmetric (diffusion along x and –x are equal), whereas the distribution of fibre orientations within a voxel is generally not symmetric. Therefore, different sub-voxel patterns such as crossing, fanning, or sharp bending, cannot be distinguished by fitting a voxel-wise model to the signal. However, asymmetric fibre patterns can potentially be distinguished once spatial information from neighbouring voxels is taken into account. We propose a neighbourhood-constrained spherical deconvolution approach that is capable of inferring asymmetric fibre orientation distributions (A-fods). Importantly, we further design and implement a tractography algorithm that utilises the estimated A-fods, since the commonly used streamline tractography paradigm cannot directly take advantage of the new information. We assess performance using ultra-high resolution histology data where we can compare true orientation distributions against sub-voxel fibre patterns estimated from down-sampled data. Finally, we explore the benefits of A-fods-based tractography using in vivo data by evaluating agreement of tractography predictions with connectivity estimates made using different in-vivo modalities. The proposed approach can reliably estimate complex fibre patterns such as sharp bending and fanning, which voxel-wise approaches cannot estimate. Moreover, histology-based and in-vivo results show that the new framework allows more accurate tractography and reconstruction of maps quantifying (symmetric and asymmetric) fibre complexity.



http://ift.tt/2tdiBLJ

Neural inhibition can explain negative BOLD responses: A mechanistic modelling and fMRI study

Publication date: September 2017
Source:NeuroImage, Volume 158
Author(s): S. Sten, K. Lundengård, S.T. Witt, G. Cedersund, F. Elinder, M. Engström
Functional magnetic resonance imaging (fMRI) of hemodynamic changes captured in the blood oxygen level-dependent (BOLD) response contains information of brain activity. The BOLD response is the result of a complex neurovascular coupling and comes in at least two fundamentally different forms: a positive and a negative deflection. Because of the complexity of the signaling, mathematical modelling can provide vital help in the data analysis. For the positive BOLD response, there are plenty of mathematical models, both physiological and phenomenological. However, for the negative BOLD response, no physiologically based model exists. Here, we expand our previously developed physiological model with the most prominent mechanistic hypothesis for the negative BOLD response: the neural inhibition hypothesis. The model was trained and tested on experimental data containing both negative and positive BOLD responses from two studies: 1) a visual-motor task and 2) a working-memory task in conjunction with administration of the tranquilizer diazepam. Our model was able to predict independent validation data not used for training and provides a mechanistic underpinning for previously observed effects of diazepam. The new model moves our understanding of the negative BOLD response from qualitative reasoning to a quantitative systems-biology level, which can be useful both in basic research and in clinical use.



http://ift.tt/2tHhBTo

Scholar : These new articles for Annals of GIS are available online

The online platform for Taylor & Francis Online content New for Annals of GIS and online now on Taylor & Francis Online: Reviews An assessment of groundwater contamination in Central Valley aquifer, California using geodetector method Anil Shrestha & Wei Luo Pages: 1-18 | DOI: 10.1080/19475683.2017.1346707 Read selected content from the Journal of Structural Integrity and Maintenance for free! http://ift.tt/2coiFom To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Scholar : These new articles for Acta Agriculturae Scandinavica, Section B — Soil & Plant Science are available online

The online platform for Taylor & Francis Online content New for Acta Agriculturae Scandinavica, Section B — Soil & Plant Science and online now on Taylor & Francis Online: Short Communications Reactive natural phosphate enriched with filter cake enhances soil P content and noni seedlings growth Gustavo Caione, Cid Naudi Silva Campos, Flávia Bastos Agostinho, Leandro Rosatto Moda, Renato de Mello Prado & Rafael Ferreira Barreto Pages: 1-4 | DOI: 10.1080/09064710.2017.1349171 Browse papers on image & data fusion, GIS, LiDAR & more in the International Journal of Image and Data Fusion's exclusive Editor's Choice collection. To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Differential expression of albumins and globulins of wheat flours of different technological qualities revealed by nanoUPLC-UDMSE

Publication date: Available online 12 July 2017
Source:Food Chemistry
Author(s): Verônica Cristina Mayrinck Victorio, Gustavo H.M.F. Souza, Millena Cristina Barros Santos, Andrés Rodríguez Vega, L.C. Cameron, Mariana Simões Larraz Ferreira
Soluble proteins were extracted from common wheat flour obtained from nine cultivars of different qualities and were analyzed by nanoUPLC and Ultra Definition Mass Spectrometry (UDMS^E) label-free quantitative approach. Collectively, 5,894 proteins were identified and quantified with 8 peptides/protein. A total of 414 proteins were found differentially expressed with 85% proteins not yet described in the literature, according to their biological function. Quality-related proteins, such as puroindolines and chaperones, notably involved in the gluten-protein folding process, were up-regulated in superior (SP) and medium (MD) flours qualities and down-regulated in the low (LW) ones. Domains related to the chaperones activity were also found up-regulated in SP and MD and down-regulated in LW. In this work, nanoUPLC-UDMS^E analysis was effective to identify and quantify metabolic proteins, allowing a clear distinction of the wheat flours and providing new perspectives for evaluating the technological quality based on the low abundant proteins of wheat endosperm.



http://ift.tt/2sPiNBe

Scholar : These new articles for Journal of Tourism and Cultural Change are available online

The online platform for Taylor & Francis Online content New for Journal of Tourism and Cultural Change and online now on Taylor & Francis Online: Original Articles Resident perception of dark tourism impact: the case of Beichuan County, China Jinwei Wang & Xianrong Luo Pages: 1-19 | DOI: 10.1080/14766825.2017.1345918 To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Scholar : These new articles for Critical Discourse Studies are available online

The online platform for Taylor & Francis Online content New for Critical Discourse Studies and online now on Taylor & Francis Online: Original Articles The field-specific representation of climate change in factual television: a multimodal critical discourse analysis Andrea Sabine Sedlaczek http://ift.tt/2u85Pm8 Pages: 1-17 | DOI: 10.1080/17405904.2017.1352003 Listening Leaders Free Accessarticles from International Listening Association Lifetime Achievement AwardeesFind out more To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Scholar : These new articles for American Review of Canadian Studies are available online

The online platform for Taylor & Francis Online content New for American Review of Canadian Studies and online now on Taylor & Francis Online: Article Development in Nunavik: How Regional and Local Initiatives Redefine Sustainable Development in Nunavik Thierry Rodon Pages: 1-13 | DOI: 10.1080/02722011.2017.1347993 Find out more about the issues and challenges in Governing Asia. This collection includes free access papers on security challenges, the Abe and Modi administration, reflections on the Chinese Governance and more. Browse today! To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Cancer incidence in the AGRICAN cohort study (2005–2011)

Publication date: August 2017
Source:Cancer Epidemiology, Volume 49
Author(s): Clémentine Lemarchand, Séverine Tual, Noémie Levêque-Morlais, Stéphanie Perrier, Aurélien Belot, Michel Velten, Anne-Valérie Guizard, Elisabeth Marcotullio, Alain Monnereau, Bénédicte Clin, Isabelle Baldi, Pierre Lebailly
BackgroundNumerous studies have been conducted among farmers, but very few of them have involved large prospective cohorts, and few have included a significant proportion of women and farm workers. Our aim was to compare cancer incidence in the cohort (overall, by sex, and by work on farm, occupational status and pesticide use) within the general population.MethodsMore than 180,000 participants in the AGRICAN cohort were matched to cancer registries to identify cancer cases diagnosed from enrolment (2005–2007) to 31st December 2011. We calculated standardized incidence ratios (SIRs) and 95% confidence intervals (95%CIs).ResultsOver the period, 11,067 incident cancer cases were identified (7304 men and 3763 women). Overall cancer incidence did not differ between the cohort and the general population. Moreover, SIRs were significantly higher for prostate cancer (SIR=1.07, 95%CI 1.03–1.11) and non-Hodgkin lymphoma (SIR=1.09, 95%CI 1.01–1.18) among men, skin melanoma among women (SIR=1.23, 95%CI 1.05–1.43) and multiple myeloma (men: SIR=1.38, 95%CI 1.18–1.62; women: SIR=1.26, 95%CI 1.02–1.54). In contrast, SIRs were lower for upper aerodigestive tract and respiratory cancers. Increase in risk was greater in male farm workers for prostate and lip cancer, in female farm workers for skin melanoma, and in male farm owners for multiple myeloma. Moreover, incidence of multiple myeloma and skin melanoma was higher among male and female pesticide users respectively.ConclusionWe found a decreased incidence for tobacco-related cancers and an increased incidence of prostate cancers, skin melanoma and multiple myeloma. Specific subgroups had a higher cancer incidence related to occupational status and pesticide use.



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Safety of treatment with nivolumab after ipilimumab-related meningoradiculitis and bilateral optic neuropathy

Publication date: September 2017
Source:European Journal of Cancer, Volume 83
Author(s): W. Boisseau, M. Touat, G. Berzero, J. Savatovsky, A. Marabelle, V. Touitou, D. Ricard, G. Malouf, D. Psimaras




http://ift.tt/2u80H1m

BCR-ABL1-like acute lymphoblastic leukaemia: From bench to bedside

Publication date: September 2017
Source:European Journal of Cancer, Volume 82
Author(s): Judith M. Boer, Monique L. den Boer
Acute lymphoblastic leukaemia (ALL) occurs in approximately 1:1500 children and is less frequently found in adults. The most common immunophenotype of ALL is the B cell lineage and within B cell precursor ALL, specific genetic aberrations define subtypes with distinct biological and clinical characteristics. With more advanced genetic analysis methods such as whole genome and transcriptome sequencing, novel genetic subtypes have recently been discovered. One novel class of genetic aberrations comprises tyrosine kinase-activating lesions, including translocations and rearrangements of tyrosine kinase and cytokine receptor genes. These newly discovered genetic aberrations are harder to detect by standard diagnostic methods such as karyotyping, fluorescent in situ hybridisation (FISH) or polymerase chain reaction (PCR) because they are diverse and often cryptic. These lesions involve one of several tyrosine kinase genes (among others, v-abl Abelson murine leukaemia viral oncogene homologue 1 (ABL1), v-abl Abelson murine leukaemia viral oncogene homologue 2 (ABL2), platelet-derived growth factor receptor beta polypeptide (PDGFRB)), each of which can be fused to up to 15 partner genes. Together, they compose 2–3% of B cell precursor ALL (BCP-ALL), which is similar in size to the well-known fusion gene BCR-ABL1 subtype. These so-called BCR-ABL1-like fusions are mutually exclusive with the sentinel translocations in BCP-ALL (BCR-ABL1, ETV6-RUNX1, TCF3-PBX1, and KMT2A (MLL) rearrangements) and have the promising prospect to be sensitive to tyrosine kinase inhibitors similar to BCR-ABL1. In this review, we discuss the types of tyrosine kinase-activating lesions discovered, and the preclinical and clinical evidence for the use of tyrosine kinase inhibitors in the treatment of this novel subtype of ALL.



http://ift.tt/2sOUPGm

Assessment of biofilm changes and concentration-depth profiles during arsenopyrite oxidation by Acidithiobacillus thiooxidans

Abstract

Biofilm formation and evolution are key factors to consider to better understand the kinetics of arsenopyrite biooxidation. Chemical and surface analyses were carried out using Raman spectroscopy, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), glow discharge spectroscopy (GDS), and protein analysis (i.e., quantification) in order to evaluate the formation of intermediate secondary compounds and any significant changes arising in the biofilm structure of Acidithiobacillus thiooxidans during a 120-h period of biooxidation. Results show that the biofilm first evolves from a low cell density structure (1 to 12 h) into a formation of microcolonies (24 to 120 h) and then finally becomes enclosed by a secondary compound matrix that includes pyrite (FeS₂)-like, S_n²⁻/S⁰, and As₂S₃ compounds, as shown by Raman and SEM-EDS. GDS analyses (concentration-depth profiles, i.e., 12 h) indicate significant differences for depth speciation between abiotic control and biooxidized surfaces, thus providing a quantitative assessment of surface-bulk changes across samples (i.e. reactivity and /or structure-activity relationship). Respectively, quantitative protein analyses and CLSM analyses suggest variations in the type of extracellular protein expressed and changes in the biofilm structure from hydrophilic (i.e., exopolysaccharides) to hydrophobic (i.e., lipids) due to arsenopyrite and cell interactions during the 120-h period of biooxidation. We suggest feasible environmental and industrial implications for arsenopyrite biooxidation based on the findings of this study.

http://ift.tt/2sPhRgl

Scholar : These new articles for Anxiety, Stress, & Coping are available online

The online platform for Taylor & Francis Online content New for Anxiety, Stress & Coping and online now on Taylor & Francis Online: Original Articles High dose alcohol consumption predicts less reduction in post-traumatic stress symptoms after a campus mass shooting Jacob B. Holzman, David P. Valentiner http://ift.tt/2t3jY4j, Susan M. Hannan, Douglas G. Wallace & Holly K. Orcutt Pages: 1-10 | DOI: 10.1080/10615806.2017.1348297 QHW publishes new thematic cluster on ADHD International Journal of Qualitative Studies on Health and Well-being (QHW) is an open access peer reviewed scientific journal that provides a forum for the exchange of data, knowledge, theoretical framework and methods on health and well-being.Read the journal's thematic cluster on ADHD today. To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Scholar : These new articles for Archives of Agronomy and Soil Science are available online

The online platform for Taylor & Francis Online content New for Archives of Agronomy and Soil Science and online now on Taylor & Francis Online: Original Articles Organic amendments as a source of phosphorus: agronomic and environmental impact of different animal manures applied to an acid soil Carmo Horta, Marta Roboredo, João Paulo Carneiro, António Canatário Duarte, José Torrent & Andrew Sharpley Pages: 1-15 | DOI: 10.1080/03650340.2017.1346372 Browse papers on image & data fusion, GIS, LiDAR & more in the International Journal of Image and Data Fusion's exclusive Editor's Choice collection. To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Enhanced ferromagnetism in edge enriched holey/lacey reduced graphene oxide nanoribbons

Publication date: 15 October 2017
Source:Materials & Design, Volume 132
Author(s): Vikrant Sahu, V.K. Maurya, Gurmeet Singh, S. Patnaik, Raj Kishore Sharma
Incorporation of magnetism in graphene based compounds holds great promise for potential spintronic applications. By optimizing point defects and high edge density of defects, we report many-fold increase in the ferromagnetic saturation moment in lacey/holey reduced graphene oxide nanoribbons (LRGONR) as compared to other graphene derivatives. The samples were synthesized using chemical unzipping methodology. Detailed structural and morphological characterizations are discussed that include XRD, Raman, SEM, HRTEM and XPS measurements. Brilluoin function analysis to magnetization data reflects best fit for J=7/2 with a saturation moment of 1.1emu/g. The microscopic origin of magnetization in LRGONR is assigned to high edge defect density which has also been correlated to microstructure.

Graphical abstract

http://ift.tt/2u86eoO

Microstructural characteristics and densification behavior of high-Nb TiAl powder produced by plasma rotating electrode process

Publication date: 15 October 2017
Source:Materials & Design, Volume 132
Author(s): Weiwei He, Yong Liu, Huiping Tang, Yunping Li, Bin Liu, Xiaopeng Liang, Zhengping Xi
In the present research, the microstructure and phase composition of high-Nb TiAl powder, produced by plasma rotating electrode process (PREP) have been investigated in details. PREPed powder with a mean particle size larger than 150μm demonstrates a dendrite structure, and that smaller than 75μm indicates a martensitic structure. PREPed powder is mainly composed of a hexagonal a2 phase, while in fine powder and coarse powders minor β phase and γ phase are detected, respectively, which is related to solidification path and cooling rate of molten droplets in PREP process. Phase composition and microstructure of the high-Nb TiAl powder have intrinsic effects on the resultant microstructure of hot isostatic pressed (HIPed) billets. After HIP processing, most martensitic and dendritic particles transformed into near γ structure, while few coarse dendritic powder was prone to introduce defects, such as residual primary particle boundaries (PPBs) or coarse lamellae structure, which were harmful to the mechanical properties of HIPed billets. The residual primary particle boundaries (PPBs) or coarse lamellae structure obviously decreased the ultimate tensile strength at room and elevated temperature.

Graphical abstract

http://ift.tt/2u7JtB3

Recrystallization behavior of multi-directionally forged over-aged and solution treated Al-Cu-Mg alloy during non-isothermal annealing

Publication date: 15 October 2017
Source:Materials & Design, Volume 132
Author(s): Saeed Khani Moghanaki, Mohsen Kazeminezhad, Roland Logé
The recrystallization behavior of an Al-Cu-Mg alloy is investigated in multi-directionally forged over-aged and solution treated alloys, during non-isothermal annealing. Deformation and non-isothermal annealing are performed with a Gleeble 3800 thermo-mechanical simulator. The hardness measurements show that there is a thermal stability in mechanical properties during non-isothermal annealing up to 250°C with heating rate of 10K·min⁻¹. Differential scanning calorimetry curves of deformed over-aged and solution treated alloys describe the related precipitation phenomena. EBSD maps demonstrate that partially recrystallized and fully recrystallized microstructures appear in deformed over-aged and solution treated alloys, respectively. During over ageing, small S′/S particles are formed and increase the critical particle diameter for particle stimulated nucleation (PSN). Evidence is also reported on grain boundary bulging in the over-aged alloy, related to strain induced grain boundary migration (SIBM). In the solution treated case, since there is not sufficient time for S′/S phase growth during non-isothermal annealing, Zener pinning pressure is reduced and PSN sites can be activated. The association of recrystallized microstructure and randomly oriented grains confirms that PSN is the governing nucleation mechanism in deformed solution treated alloys. In the deformed over-aged alloy, a strong γ-fiber is developed by consuming other texture components like {001}〈110〉.

Graphical abstract

http://ift.tt/2u7Xyib

On the microstructural refinement in commercial purity Al and Al-10wt% Cu alloy under ultrasonication during solidification

Publication date: 15 October 2017
Source:Materials & Design, Volume 132
Author(s): H.R. Kotadia, M. Qian, D.G. Eskin, A. Das
Physical grain refinement is examined under high-intensity ultrasonication during solidification in commercial purity Al (CP-Al) and binary Al-10wt% Cu alloy melts cooled naturally in air and compared against chemical inoculation using Al-5Ti-1B grain refiner. The coarse dendritic unrefined base microstructure was completely replaced with a fine equiaxed grain structure in the case of either inoculation or ultrasonication. However, ultrasonication produced more effective refinement over chemical inoculation with a two-fold and eight-fold increase in the grain density in CP-Al and Al-10%Cu alloy, respectively. While combining chemical inoculation with ultrasonication produced the finest grain structure in CP-Al, no further improvement over ultrasonication was noted for the Al-10%Cu alloy. Noticeable reduction in nucleation undercooling, of similar magnitude to chemical inoculation, was observed under ultrasonication. Cooling curve observations indicate strongly enhanced heterogeneous nucleation under ultrasonication. It appears that although chemical inoculation utilises higher potency nucleants, more nucleation events are favoured under cavitation.

Graphical abstract

http://ift.tt/2u7RDJK

Microstructure and mechanical properties of keyhole repair welds in AA 7075-T651 using refill friction stir spot welding

Publication date: 15 October 2017
Source:Materials & Design, Volume 132
Author(s): Martin Reimann, Jannik Goebel, Jorge F. dos Santos
To develop a suitable keyhole closure process in high-strength AlZnMg(Cu) alloys, refill friction stir spot welding was used to perform repair welds of through holes of 7.5mm diameter in AA 7075-T651 plates with 6mm thickness. The thermal cycle and the evolution of microstructural features were investigated in detail. The mechanical performance of the welds was studied based on the changes in microstructure and temperature exposure caused by the welding process.Thermal cycle measurements revealed high heating rates and peak temperatures of up to 540°C in the weld center. Leftover grains from the base metal that did not recrystallize were determined in the stirred zone of the weld center. The welds showed a W-shaped hardness distribution with a lowest hardness of 70% of base metal values in the heat affected zone. Under quasi-static loading, two failure modes were determined, with mode 1 failure occurring in the heat affected zone and mode 2 failure occurring in the outer regions of the stirred zone with crack initiation in the lower portions of the weld. Post-weld natural aging was proven to be highly significant for the mechanical properties of the welds and is effective for up to 4weeks after welding.

Graphical abstract

http://ift.tt/2u8gGN3

Friction spot welding between porous TC4 titanium alloy and ultra high molecular weight polyethylene

Publication date: 15 October 2017
Source:Materials & Design, Volume 132
Author(s): Ke Chen, Binxi Chen, Shanyong Zhang, Min Wang, Lanting Zhang, Aidang Shan
Due to the advantages of light-weight, excellent integrated physical/chemical properties and design flexibility, metal/polymer hybrid structures have been increasingly used in automotive, aerospace and biomedical industries, which calls for effective method for joining metal and polymer. In this study, biomedical 3D-printed porous TC4 titanium alloy plate and ultra high molecular weight polyethylene (UHMWPE) plate were successfully joined by friction spot welding (FSpW) technology. The unique welding temperature (Tw) - z-axis force (Fz) evolution at the TC4 plate/UHMWPE plate interface were characterized. During dwell stage, Tw and Fz were identified to be coupled. An arch-shaped embedded zone (EZ) which characterized by the embedment of UHMWPE into porous TC4 formed under non-uniformly distributed Tw at the interface, which provided the most effective bonding mechanism. The porous structure of TC4 plate is critical for the mechanical interfacial bonding formation. As a result, TC4/UHMWPE joints of high lap shear strength can be obtained by forming large EZ. Failure occurred at either TC4 or UHMWPE base plates rather than the TC4 plate/UHMWPE plate interface.

Graphical abstract

http://ift.tt/2u7hIJe

Why human anti-Galα1–4Galβ1–4Glc natural antibodies do not recognize the trisaccharide on erythrocyte membrane? Molecular dynamics and immunochemical investigation

Publication date: October 2017
Source:Molecular Immunology, Volume 90
Author(s): Pavel Volynsky, Roman Efremov, Ilya Mikhalev, Kira Dobrochaeva, Alexander Tuzikov, Elena Korchagina, Polina Obukhova, Evgenia Rapoport, Nicolai Bovin
BackgroundHuman blood contains a big variety of natural antibodies, circulating throughout life at constant concentration. Previously, we have found natural antibodies capable of binding to trisaccharide Galα1-4Galβ1-4Glc (P^k) practically in all humans. Intriguingly, the same trisaccharide is a key fragment of glycosphingolipid globotriaosylceramide (Gb3Cer) – normal component of erythrocyte and endothelial cell membrane, i.e. the antibodies and their cognate antigen coexist without any immunological reaction.AimTo explain the inertness of human anti-P^k antibodies towards own cells.Materials and methodsWe used a combination of immunochemical and molecular dynamics (MD) experiments. Antibodies were isolated using affinity media with P^k trisaccharide, their epitope specificity was characterized using ELISA (enzyme-linked immunosorbent assay) with a set of synthetic glycans related to P^k synthetic glycans and FACS (Fluorescence-Activated Cell Sorting) analysis of cells with inserted natural Gb3Cer and its synthetic analogue. Conformations and clustering of glycolipids immersed into a lipid bilayer were studied using MD simulations.ResultsIsolated specific antibodies were completely unable to bind natural Gb3Cer both inserted into cells and in artificial membrane, whereas strong interaction took place with synthetic analogue differing by the presence of a spacer between trisaccharide and lipid part. MD simulations revealed: i) although membrane-bound glycans do not form stable long-living aggregates, their transient packing is more compact in natural Gb3 as compared with the synthetic analog, ii) similar conformation of P^k glycan in composition of the glycolipids, iii) no effect on the mentioned above results when cholesterol was inserted into membrane, and iv) better accessibility of the synthetic version for interaction with proteins.ConclusionsBoth immunochemical and molecular dynamics data argue that the reason of the "tolerance" of natural anti-P^k antibodies towards cell-bound Gb3Cer is the spatial inaccessibility of P^k glycotope for interaction. We can conclude that the antibodies are not related to the blood group P system.



http://ift.tt/2u7Q26E

CD3/CD28 dynabeads induce expression of tn antigen in human t cells accompanied by hypermethylation of the cosmc promoter

Publication date: October 2017
Source:Molecular Immunology, Volume 90
Author(s): Chuanqin Shi, Xue Xu, Xiaofeng Yu, Zhenzhen Du, Xiying Luan, Dachang Liu, Tao Hu
Glycosylation is an important protein post-translational modification. In this process, the intermediate product, Tn antigen, arises from somatic mutations in core1β3-galactosyltransferase-specific molecular chaperone (Cosmc), which is required for the formation of active core1β3-galactosyltransferase (T-synthase). As a type of tumor-associated carbohydrate antigen, Tn antigen is mainly expressed in many human tumor cells and is absent in normal cells. Surprisingly, it is also expressed in normal activated T cells after in vitro stimulation, but the mechanism underlying its expression remains unclear. This study demonstrated that Tn antigen was expressed in activated T cells and that the percentage of positive (Tn⁺) cells increased and subsequently decreased within 72h after stimulation with CD3/CD28 Dynabeads, with peak expression occurring at 48h. During activation, interleukin-4 (IL-4) expression in the T-cell supernatant consistently increased with Tn⁺ cells, and was inversely correlated with serum interferon gamma (IFN-γ) levels. Compared with unactivated (without CD3/CD28 Dynabead stimulation) T cells, the level of T-synthase transcription in activated T cells did not significantly change, whereas T-synthase activity and Cosmc transcription significantly decreased, accompanied by a further increase in methylation of the Cosmc promoter. The results also showed that Cosmc transcription and translation decreased and then increased, and that Cosmc promoter methylation was a dynamic process during T cell activation. These data suggest that hypermethylation of the Cosmc promoter may induce the expression of Tn antigen in activated T cells.



http://ift.tt/2sPi7Mv

Methotrexate, combined with cyclophosphamide attenuates murine collagen induced arthritis by modulating the expression level of Breg and DCs

Publication date: October 2017
Source:Molecular Immunology, Volume 90
Author(s): Jinnan Fan, Jing Luo, Caiping Yan, Runxi Hao, Xiangcong Zhao, Ruihuan Jia, Jiaojiao He, Dan Xu, Miao Miao, Xiaofeng Li
To explore the mechanism of methotrexate (MTX) and its combination with cyclophosphamide (CTX) in collagen-induced arthritis (CIA), we investigated the levels of several immune cells and cytokines in mice with different treatments. CIA was induced in DBA/1 mice at the age of 7 weeks by primary immunization with 100μl emulsion containing 2mg/ml bovine type II collagen which was mixed with complete Freund's adjuvant (CFA). The booster immunization was performed with 50–100μl emulsion containing 2mg/ml bovine type II collagen (CII) mixed with incomplete Freund's adjuvant (IFA). MTX, CTX or both were administrated after the booster immunization. Therapeutic effect was evaluated by arthritic scores, X-rays and assessment of histopathological joint destruction. The expression of TNF-α, IL-6, IL-23, IL-10 were also measured. The frequencies of different immune cell subsets in the lymph node, spleen and bone marrow were determined by flow cytometry analysis. Our results showed that CTX and MTX treatment attenuated the severity of arthritis of CIA mice and reduced the levels of several cytokines. CTX and MTX treated mice showed a lower frequency of B cells in bone marrow. Also, when treated the CIA mice with MTX, alone or together with CTX, the lymph nodes and spleen exhibited a decrease in regulatory B cells (Breg) and dendritic cells (DCs). Notably, the combination of MTX and CTX had a more pronounced effect. By measuring the levels of different immune cells those participated in the development of rheumatoid arthritis (RA), our experiment may help to evaluate the therapeutic effects and prognosis of arthritic diseases.



http://ift.tt/2u82LXk

Scholar : These new articles for AIDS Care are available online

The online platform for Taylor & Francis Online content New for AIDS Care and online now on Taylor & Francis Online: Original Articles "I did not see a need to get tested before, everything was going well with my health": a qualitative study of HIV-testing decision-making in Kwazulu-Natal, South Africa Shema Tariq http://ift.tt/2uhHcDU, Susie Hoffman, Gita Ramjee, Joanne E. Mantel, Jessica L. Phillip, Kelly Blanchard, Naomi Lince-Deroche & Theresa M. Exner Pages: 1-8 | DOI: 10.1080/09540121.2017.1349277 Routledge Psychology 2017 sponsor of BPS #PsychCrunch podcasts. Access 25 journal articles: http://bit.ly/psychcrunch2017 To update which email alerts you receive, manage your alerts within the My Account area. You can also unsubscribe from this alert with one click. If you need any further help, please contact us at support@tandfonline.com Please do not reply to this email. To ensure that you receive your alerts and information from Taylor & Francis Online, please add "alerts@tandfonline.com" and "info@tandfonline.com" to your safe senders list. Taylor & Francis, an Informa business. Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954. Registered office: 5 Howick Place, London, SW1P 1WG.

Aging, rule-violation checking strategies, and strategy combination: An EEG study in arithmetic

Publication date: Available online 12 July 2017
Source:International Journal of Psychophysiology
Author(s): Thomas Hinault, Patrick Lemaire
In arithmetic, rule-violation checking strategies are used while participants solve problems that violate arithmetic rules, like the five rule (i.e., products of problems including five as an operand end with either five or zero; e.g., 5×14=70) or the parity rule (i.e., when at least one of the two operands is even, the product is also even; otherwise the product is odd; e.g., 4×13=52). When problems violate both rules, participants use strategy combination and have better performance on both-rule than on one-rule violation problems (i.e., five or parity rule). Aging studies found that older adults efficiently use one-rule violation checking strategies but have difficulties to combine two strategies. To better understand these aging effects, we used EEG and found important age-related changes while participants used rule-violation checking strategies. We compared participants' performance while they verified arithmetic problems that differ in number and type of violated rule. More specifically, both-rule violation problems elicited larger negativity than one-rule violation problems between 600 and 800ms. Five-rule violation problems differed from parity-rule violation problems between 1100 and 1200ms. Moreover, rule-violation checking strategies and strategy combination involved delta, theta, and lower alpha frequencies. Age-related changes in ERPs and frequency were associated with less efficient strategy combination. Moreover, efficient use of one-rule violation checking strategies in older adults was associated with changes in ERPs and frequency. These findings contribute to further our understanding of age-related changes and invariance in arithmetic strategies, and in combination of arithmetic strategies.



http://ift.tt/2t3035E

Use of fourier transform infrared spectroscopy to examine the Fe(II)-Catalyzed transformation of ferrihydrite

Publication date: 1 December 2017
Source:Talanta, Volume 175
Author(s): Wei Xiao, Adele M. Jones, Richard N. Collins, Mark W. Bligh, T. David Waite
The Fe(II)-catalyzed transformation of the poorly crystalline Fe(III) oxyhydroxide mineral, ferrihydrite (Fh), to more crystalline Fe(III) mineral species such as magnetite, goethite, and lepidocrocite has been quantitatively evaluated under various conditions using X-ray adsorption spectroscopy (XAS) and Fourier transform infrared (FTIR) spectroscopy. Using the peak height of signature FTIR peaks of sub-micron sized lepidocrocite and goethite references minerals, the FTIR results were comparable to the XAS results within experimental error. This was independent of whether the Fe(II)-catalyzed transformation was initiated by the Fe(III)-reducing bacterium Shewanella oneidensis MR-1 or by added ferrous ammonium sulfate in the presence or absence of lactate. Whilst the use of FTIR has not been previously employed to follow this transformation process, it has advantages relative to XAS including a lower sample requirement (approximately 30-fold lower), greater accessibility and greater safety of operation. Whilst problems with quantifying magnetite in the presence of lepidocrocite were identified in this study using reference Fe(III) oxyhydroxide suspensions, large amounts of magnetite were not produced during transformation under the conditions employed in this study. Reference spectra of lath-like nano-goethite particles (with dimensions of approx. 10 × 50nm) also resulted in higher IR absorbance and a slight red-shift in signature peak positions relative to sub-micron sized goethite particles with this shift potentially affecting the reliable quantification of samples of unknown size. Despite this, good agreement between the XAS and FTIR data for samples containing iron oxides undergoing continuous transformation was obtained suggesting that FTIR may be a convenient, inexpensive means of following such mineral transformations.

Graphical abstract

http://ift.tt/2tdv81H

Microcystin-LR label-free immunosensor based on exfoliated graphite nanoplatelets and silver nanoparticles

Publication date: 1 December 2017
Source:Talanta, Volume 175
Author(s): Nicole Zanato, Lucas Talamini, Tânia Regina Silva, Iolanda Cruz Vieira
This paper describes a simple, rapid and accurate label-free immunosensor for the determination of MC-LR in water samples. The anti-MC-LR was immobilized in a hybrid nanocomposite, comprised of exfoliated graphite nanoplatelets dispersed in a suspension of silver nanoparticles (AgNP-Nafion-xGnP), by adsorption. The nanomaterial obtained was then employed to prepare an immunosensor using a glassy carbon electrode (GCE) in one-step. Under optimized conditions, using square-wave voltammetry (SWV) and an incubation time of 10min, the immunosensor showed a linear relationship between the oxidation current and MC-LR concentration in the range of 0.5–5000ngmL⁻¹ with a detection limit of 0.017ngmL⁻¹. The immunosensor demonstrated good precision, with coefficients of variation of 4.5% (inter-day; n = 7) and 3.1% (intra-day; n = 5), and acceptable selectivity (low interference in the presence of potential interferents), indicating that it is suitable for analytical applications. The immunosensor was successfully applied in the determination of MC-LR in a water sample and this platform offers advantages when compared to other electrochemical sensors reported in the literature, especially with regard to the time of incubation.

Graphical abstract

http://ift.tt/2td3qSP

Ethyl acetate extract from Panax ginseng C.A. Meyer and its main constituents inhibit α-melanocyte-stimulating hormone-induced melanogenesis by suppressing oxidative stress in B16 mouse melanoma cells

Publication date: 17 August 2017
Source:Journal of Ethnopharmacology, Volume 208
Author(s): Rui Jiang, Xiao-Hao Xu, Ke Wang, Xin-Zhao Yang, Ying-Fei Bi, Yao Yan, Jian-Zeng Liu, Xue-Nan Chen, Zhen-Zhong Wang, Xiao-Li Guo, Da-Qing Zhao, Li-Wei Sun
Ethnopharmacological relevanceHyperpigmentation disease involves darkening of the skin color due to melanin overproduction. Panax ginseng C.A. Meyer is a well-known traditional Chinese medicine and has a long history of use as a skin lightener to inhibit melanin formation in China, Korea and some other Asian countries. However, the constituents and the molecular mechanisms by which they affect melanogenesis are not fully clear.Aim of the studyThe purpose of this study was to identify the active ingredient in Panax ginseng C.A. Meyer extract that inhibits mushroom tyrosinase activity and to investigate the antioxidative capacity and molecular mechanisms of the effective extract on melanogenesis in B16 mouse melanoma cells.Materials and methodsAqueous extracts of Panax ginseng C.A. Meyer were successively fractionated with an equal volume of chloroform, ethyl acetate, and n-butyl alcohol to determine the effects by examining the activity of mushroom tyrosinase. The effective fraction was analyzed using HPLC and LC-MS. The antioxidative capacity and the inhibitory effects on melanin content, cell intracellular tyrosinase activity, and melanogenesis protein levels were determined in α-melanocyte-stimulating hormone (α-MSH)-treated B16 mouse melanoma cells.ResultsThe ethyl acetate extract from Panax ginseng C.A. Meyer (PG-2) had the highest inhibiting effect on mushroom tyrosinase, mainly contained phenolic acids, including protocatechuic acid, vanillic acid, p-coumaric acid, salicylic acid, and caffeic acid, and exhibited apparent antioxidant activity in vitro. PG-2 and its main constituents significantly decreased melanin content, suppressed cellular tyrosinase activity, and reduced expression of tyrosinase protein to inhibit B16 cells melanogenesis induced by α-MSH, and no cytotoxic effects were observed. They also inhibited cellular reactive oxygen species (ROS) generation, increased superoxide dismutase (SOD) activity and glutathione (GSH) level in α-MSH-treated B16 cells effectively. And those activities of its main constituents could reach more than 80% of PG-2. The ROS scavengers N-acetyl-L-cysteine (NAC) had a similar inhibitory effect on melanogenesis.ConclusionsThese results suggest that ethyl acetate extract from Panax ginseng C.A. Meyer has the highest effect on inhibiting melanogenesis, and that its main components are polyphenolic compounds, which may inhibit melanogenesis by suppressing oxidative stress. This work provides new insight into the active constituents and molecular mechanisms underlying skin-lightening effect of Panax ginseng C.A. Meyer.

Graphical abstract

http://ift.tt/2sOJNRp

The Future of Periodontal-Systemic Associations: Raising the Standards

Abstract

Purpose of Review

Periodontal medicine recognizes a "bidirectional" interaction between periodontitis and systemic conditions. Unfortunately, the facile ability to publish a periodontal-systemic association, regardless of biologic plausibility or rigorous scientific scrutiny, continues without abate.

Recent Findings

The increasing number of periodontal-systemic associations corrupts the ability of dentists to distinguish which of the associations are spurious and which are valid.

Summary

The use of a Disease Association Checklist creates a register for rational assessment of current disease associations. However, to diminish the publication of spurious periodontal-systemic observational associations, editors must demand that authors follow Bradford-Hill criteria and the STROBE Statement to ensure a stringent pathway to publication.

http://ift.tt/2vb67W7

Biomass-derived heteroatoms-doped mesoporous carbon for efficient oxygen reduction in microbial fuel cells

Publication date: 15 December 2017
Source:Biosensors and Bioelectronics, Volume 98
Author(s): Yu Lu, Nengwu Zhu, Fuhua Yin, Tingting Yang, Pingxiao Wu, Zhi Dang, Meilin Liu, Xiaorong Wei
Currently, the development of less expensive, more active and more stable catalysts like heteroatom-doped carbon based non-precious metal materials are highly desired for the cathodic oxygen reduction reaction (ORR) in microbial fuel cells (MFCs). Comparing with heteroatom sources from chemical reagents, biomass is notably inexpensive and abundant, containing more elements which contribute to ORR activity. Herein, we demonstrate an easy operating one-step and low-cost way to synthesize egg-derived heteroatoms-doped mesoporous carbon (EGC) catalysts utilizing egg as the biomass carbon and other elements source (sulphur, phosphorus, boron and iron), and porous g-C3N4 as both template and nitrogen source. After carbonized, such hybrid materials possess an outstanding electrocatalytic activity towards ORR comparable to the commercial Pt/C catalyst in neutral media. Electrochemical detections as cyclic voltammogram and rotating ring-disk electrode tests show that the potential of oxygen reduction peak of EGC1-10-2 is at + 0.10V, onset potential is at + 0.257V (vs. Ag/AgCl) and electron transfer number of that is 3.84–3.92, which indicate that EGC1-10-2 via a four-electron pathway. Reactor operation shows that the maximum power density of MFC-EGC1-10-2 (737.1mWm⁻²), which is slightly higher than MFC-Pt/C (20%) (704mWm⁻²). The low cost (0.049 $g⁻¹), high yield (20.26%) and high performance of EGC1-10-2 provide a promising alternative to noble metal catalysts by using abundant natural biological resources, which contribute a lot to expansion and commercialization of MFCs.



http://ift.tt/2vbiIsH

Electrochemical DNA biosensor based on grafting-to mode of terminal deoxynucleoside transferase-mediated extension

Publication date: 15 December 2017
Source:Biosensors and Bioelectronics, Volume 98
Author(s): Jinyuan Chen, Zhoujie Liu, Huaping Peng, Yanjie Zheng, Zhen Lin, Ailin Liu, Wei Chen, Xinhua Lin
Previously reported electrochemical DNA biosensors based on in-situ polymerization approach reveal that terminal deoxynucleoside transferase (TdTase) has good amplifying performance and promising application in the design of electrochemical DNA biosensor. However, this method, in which the background is significantly affected by the amount of TdTase, suffers from being easy to produce false positive result and poor stability. Herein, we firstly present a novel electrochemical DNA biosensor based on grafting-to mode of TdTase-mediated extension, in which DNA targets are polymerized in homogeneous solution and then hybridized with DNA probes on BSA-based DNA carrier platform. It is surprising to find that the background in the grafting-to mode of TdTase-based electrochemical DNA biosensor have little interference from the employed TdTase. Most importantly, the proposed electrochemical DNA biosensor shows greatly improved detection performance over the in-situ polymerization approach-based electrochemical DNA biosensor.



http://ift.tt/2ucSZm2

Detection of Ca2+-induced acetylcholine released from leukemic T-cells using an amperometric microfluidic sensor

Publication date: 15 December 2017
Source:Biosensors and Bioelectronics, Volume 98
Author(s): Mahmood H. Akhtar, Khalil K. Hussain, N.G. Gurudatt, Yoon-Bo Shim
A microfluidic structured-dual electrodes sensor comprising of a pair of screen printed carbon electrodes was fabricated to detect acetylcholine, where one of them was used for an enzyme reaction and another for a detection electrode. The former was coated with gold nanoparticles and the latter with a porous gold layer, followed by electropolymerization of 2, 2:5,2-terthiophene-3-(p-benzoic acid) (pTTBA) on both the electrodes. Then, acetylcholinesterase was covalently attached onto the reaction electrode, and hydrazine and choline oxidase were co-immobilized on the detection electrode. The layers of both modified electrodes were characterized employing voltammetry, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and quartz crystal microscopy. After the modifications of both electrode surfaces, they were precisely faced each other to form a microfluidic channel structure, where H2O2 produced from the sequential enzymatic reactions was reduced by hydrazine to obtain the analytical signal which was analyzed by the detection electrode. The microfluidic sensor at the optimized experimental conditions exhibited a wide dynamic range from 0.7nM to 1500μM with the detection limit of 0.6 ± 0.1nM based on 3s (S/N = 3). The biomedical application of the proposed sensor was evaluated by detecting acetylcholine in human plasma samples. Moreover, the Ca²⁺-induced acetylcholine released in leukemic T-cells was also investigated to show the in vitro detection ability of the designed microfluidic sensor. Interference due to the real component matrix were also studied and long term stability of the designed sensor was evaluated. The analytical performance of the designed sensor was also compared with commercially available ACh detection kit.



http://ift.tt/2vbA6x4

Amplification of electrochemical signal by a whole-cell redox reactivation module for ultrasensitive detection of pyocyanin

Publication date: 15 December 2017
Source:Biosensors and Bioelectronics, Volume 98
Author(s): Yuan Yang, Yang-Yang Yu, Yan-Zhai Wang, Chun-Lian Zhang, Jing-Xian Wang, Zhen Fang, Huoyang Lv, Jian-Jiang Zhong, Yang-Chun Yong
A bioelectrochemical sensing system based on a novel whole-cell redox reactivation/cycling module for ultrasensitive detection of pyocyanin (the biomarker of Pseudomonas aeruginosa infections) was developed. The electroactive bacteria mediated redox reactivation module was constructed using Shewanella oneidensis MR-1 cells as the bioelectro-catalyst and lactate as the electron donor. It could regenerate reductive pyocyanin from its oxidative state, which enabled pyocyanin molecule repeatedly registered by the electrode. Uniquely, with this redox reactivation module, the electrochemical response of pyocyanin was amplified about 405 times (1.3 μA/nM vs. 3.2nA/nM). Thus, an ultrasensitive bioelectrochemical sensing system for pyocyanin quantification was developed by integrating the pyocyanin reactivation module with conventional electrochemical detection system. Remarkably, with this developed biosensing system, an extremely low LOD of 47±1pM was reached. Additionally, this biosensing system showed excellent resistance to interferences from human fluids or bacterial contamination. This work provided a simple, ultrasensitive and robust tool for pyocyanin detection, and more importantly, demonstrated a new dimension for electrochemical signal amplification in biosensing.

Graphical abstract

http://ift.tt/2ucBbaV

Quantitative detection of glucose level based on radiofrequency patch biosensor combined with volume-fixed structures

Publication date: 15 December 2017
Source:Biosensors and Bioelectronics, Volume 98
Author(s): Tian Qiang, Cong Wang, Nam-Young Kim
A concept for characterizing a radiofrequency (RF) patch biosensor combined with volume-fixed structures is presented for timely monitoring of an individual's glucose levels based on frequency variation. Two types of patch biosensors—separately integrated with a backside slot (0.53μL) and a front-side tank (0.70μL) structure—were developed to achieve precise and efficient detection while excluding the effects of interference due to the liquidity, shape, and thickness of the tested glucose sample. A glucose test analyte at different concentrations (50–600mg/dL) was dropped into the volume-fixed structures. It fully interacted with the RF patch electromagnetic field, effectively and sensitively changing the resonance frequency and magnitude of the reflection coefficient. Measurement results based on the resonance frequency showed high sensitivity up to 1.13MHz and 1.97MHz per mg/dL, and low detection limits of 26.54mg/dL and 15.22mg/dL, for the two types of patch biosensors, respectively, as well as a short response time of less than 1s. Excellent reusability of the proposed biosensors was verified through three sets of measurements for each individual glucose sample. Regression analysis revealed a good linear correlation between glucose concentrations and the resonance frequency shift. Moreover, to facilitate a multi-parameter-sensitive detection of glucose, the magnitude of the reflection coefficient was also tested, and it showed a good linear correlation with the glucose concentration. Thus, the proposed approach can be adopted for distinguishing glucose solution levels, and it is a potential candidate for early-stage detection of glucose levels in diabetes patients.



http://ift.tt/2ucCE14

Sensitive detection of brucine an anti-metastatic drug for hepatocellular carcinoma at carbon nanotubes – nafion composite based biosensor

Publication date: 15 December 2017
Source:Biosensors and Bioelectronics, Volume 98
Author(s): Rutesh Savalia, Sanghamitra Chatterjee
A neoteric approach for the electrochemical analysis of brucine in biological environment has been developed. The glassy carbon electrode modified with single walled carbon nanotubes and nafion composite film is delineated for the first time to determine brucine employing square wave voltammetry. The quantification of brucine at physiological pH 7.2 manifests remarkable performance at the developed biosensor. The effect of several operational parameters has been studied in the present investigation. Under optimized conditions, a dynamic linear range from 1nM to 8µM with a high sensitivity of 340.8µAµM⁻¹ and limit of detection corresponding to 0.11nM was achieved. The interfering effect of some coexisting metabolites on the current response of brucine has been reported. The method was successfully applied for the detection of brucine in traditional pharmaceutical formulations. The biological relevance of the present method has been demonstrated by the analysis of the alkaloid in human serum and urine samples. The analytical utility was further assessed by the selective determination of brucine in Strychnos nux-vomica seeds exhibiting considerable potential as a diagnostic tool.



http://ift.tt/2vbhJsj

Architecting the myelin landscape

Publication date: December 2017
Source:Current Opinion in Neurobiology, Volume 47
Author(s): Lindsay A Osso, Jonah R Chan
Myelin increases the speed and efficiency of action potential propagation. Yet, not all axons are myelinated and some axons are discontinuously myelinated, prompting the question of how myelinating glia select axons for myelination. Whereas myelination by Schwann cells depends on axonal induction, oligodendrocytes can form myelin membrane in the absence of axons. However, oligodendrocytes alone cannot architect the complex myelination patterns of the central nervous system and recent advances have implicated axonal signaling in this process. This review considers how oligodendrocytes and their precursors could be influenced by inductive, attractive, permissive, repulsive, and preventative cues, and discusses recent evidence identifying synaptic activity and membrane-bound adhesion molecules as such cues directing axon selection.



http://ift.tt/2uPtuFB

Regulation of Rho GTPase proteins during spine structural plasticity for the control of local dendritic plasticity

Publication date: August 2017
Source:Current Opinion in Neurobiology, Volume 45
Author(s): Nathan G Hedrick, Ryohei Yasuda
While it is generally appreciated that learning involves the structural rearrangement of neuronal circuits, the underlying orchestration of molecular events that drives these changes is not as well understood. Recent studies on the spatiotemporal organization of synaptic signaling events have provided new insights into the biochemical underpinnings of various expressions of structural neuronal plasticity, as well as the functional consequences that emerge because of the particular behavior of the molecules involved. In particular, activity patterns of and interplay among a class of morphogenic signaling proteins, the Rho GTPases, and their downstream signals, are found to be critical for linking neuronal activity with various forms of neuronal plasticity. We review recent findings on this topic and discuss their physiological implications.



http://ift.tt/2uh9ize

The Effect of Methylphenidate on the Microstructure of Schedule-Induced Polydipsia in an animal model of ADHD

Publication date: 30 August 2017
Source:Behavioural Brain Research, Volume 333
Author(s): Javier Íbias, Carter W. Daniels, Miguel Miguéns, Ricardo Pellón, Federico Sanabria
Schedule-induced polydipsia (SIP) was established in spontaneously hypertensive rats (SHR), Wistar Kyoto rats (WKY), and Wistar rats, using a multiple fixed-time (FT) schedule of food delivery, with 30- and 90-s components. Thereafter, animals were exposed to methylphenidate (MPH; 2.5mg/kg/d) for six consecutive SIP sessions. A test to assess possible sensitization effects was also conducted four days after termination of the drug treatment. At baseline, FT 90-s produced longer and more frequent drinking episodes in SHR than in WKY. An analysis of the distribution of inter-lick intervals revealed that drinking was organized in bouts, which were shorter in SHR than in WKY. Across strains and schedules, MPH shifted drinking episodes towards the beginning of inter-food intervals, which may reflect a stimulant effect on SIP. MPH transiently reduced the frequency of drinking episodes in WKY in FT 30-s, and more permanently reduced the frequency of licking bouts in Wistar rats. MPH also increased the length of licking bouts in Wistar rats. Overall, SHR displayed a hyperactive-like pattern of drinking (frequent but short bouts), which 2.5mg/kg MPH appears to reduce in WKY and Wistar but not in SHR rats. It appears that therapeutic effects of MPH on hyperactive-like SIP require higher doses in SHR relative to control strains.



http://ift.tt/2tdiwYo

Implicit predictions of future rewards and their electrophysiological correlates

Publication date: 30 August 2017
Source:Behavioural Brain Research, Volume 333
Author(s): Elizabeth M. Trimber, Christian C. Luhmann
Information that is motivationally relevant to an organism's survival demands preferential attention. Affective mechanisms facilitate attentional shifts and potentiate action to allow organisms to respond appropriately to motivationally relevant information. Previous work has demonstrated that the late-positive potential (LPP) is an event-related potential elicited by inherently emotional stimuli. For example, the LPP typically is evoked by images of weapons or erotica. The present study investigates stimuli that are not inherently emotional, but that implicitly (without participants' awareness) predict future monetary gains and losses. Results indicate that, relative to non-predictive cues, these predictive cues elicited frontally distributed positive potential. These results suggest that prediction of future rewards evokes neural responses that are similar to those evoked by inherently emotional stimuli. Results also indicate that monetary gains and losses elicit a frontally distributed LPP.



http://ift.tt/2tdmhNn

Testing the physiological plausibility of conflicting psychological models of response inhibition: A forward inference fMRI study

Publication date: 30 August 2017
Source:Behavioural Brain Research, Volume 333
Author(s): Marion Criaud, Marieke Longcamp, Jean-Luc Anton, Bruno Nazarian, Muriel Roth, Guillaume Sescousse, Antonio P. Strafella, Bénédicte Ballanger, Philippe Boulinguez
The neural mechanisms underlying response inhibition and related disorders are unclear and controversial for several reasons. First, it is a major challenge to assess the psychological bases of behaviour, and ultimately brain–behaviour relationships, of a function which is precisely intended to suppress overt measurable behaviours. Second, response inhibition is difficult to disentangle from other parallel processes involved in more general aspects of cognitive control. Consequently, different psychological and anatomo-functional models coexist, which often appear in conflict with each other even though they are not necessarily mutually exclusive. The standard model of response inhibition in go/no-go tasks assumes that inhibitory processes are reactively and selectively triggered by the stimulus that participants must refrain from reacting to. Recent alternative models suggest that action restraint could instead rely on reactive but non-selective mechanisms (all automatic responses are automatically inhibited in uncertain contexts) or on proactive and non-selective mechanisms (a gating function by which reaction to any stimulus is prevented in anticipation of stimulation when the situation is unpredictable). Here, we assessed the physiological plausibility of these different models by testing their respective predictions regarding event-related BOLD modulations (forward inference using fMRI). We set up a single fMRI design which allowed for us to record simultaneously the different possible forms of inhibition while limiting confounds between response inhibition and parallel cognitive processes. We found BOLD dynamics consistent with non-selective models. These results provide new theoretical and methodological lines of inquiry for the study of basic functions involved in behavioural control and related disorders.



http://ift.tt/2tGYmcz

Perinatal protein deprivation facilitates morphine cross-sensitization to cocaine and enhances ΔFosB expression in adult rats

Publication date: 30 August 2017
Source:Behavioural Brain Research, Volume 333
Author(s): María Cecilia Perondi, María Cecilia Gutiérrez, Analía Valdomero, Gabriel Ricardo Cuadra
Previous studies have indicated that neural changes induced by early nutritional insult cause an altered response to pharmacological treatments, including addictive drugs. This study evaluates the influence of perinatal protein malnutrition in developing cross-sensitization to cocaine-induced rewarding effects in animals pre-exposed to morphine.Different groups of well-nourished (C-rats) and protein-deprived animals (D-rats) were treated twice a day for three days with increasing doses of morphine or with saline. After 3days, the incentive motivational effects of cocaine were assessed in a Conditioned Place Preference paradigm in both groups. In saline pre-treated animals, dose-response curves to cocaine revealed a conditioning effect in D-rats at doses of 5, 7.5 and 10mg/kg, while this effect was observed in C-rats only with 10 and 15mg/kg. Furthermore, when animals of both groups were pre-treated with escalating doses of morphine, cross-sensitization to the conditioning effect of cocaine was elicited only in D-rats with low doses of cocaine (5 and 7.5mg/kg). In contrast, under the same experimental conditions, C-rats show no cross-sensitization. To correlate this differential rewarding response with a molecular substrate linked to the behavioral changes observed after repeated drug exposure, ΔFosB expression was assessed in different brain regions. D-rats showed a significant increase in this transcription factor in the nucleus accumbens, amygdala and medial prefrontal cortex. These results demonstrated that perinatal protein deprivation facilitates rewarding effects and the development of cross-sensitization to cocaine, which correlates with an upregulation of ΔFosB in brain areas related to the reward circuitry.



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Formation of brominated and chlorinated dioxins and its prevention during a pilot test of mechanochemical treatment of PCB and PBDE contaminated soil

Abstract

The destruction of persistent organic pollutants (POPs) is a large challenge in particular in developing and emerging economies. To date, a detailed assessment of non-combustion technologies with respect to formation of dioxins is lacking. In this study, an assessment of mechanochemical (MC) destruction technology for polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in contaminated soil remediation was conducted. Actual applied conditions of pilot-scale MC POPs destruction process indicates that the temperature increase inside the ball mills has the potential to form high levels of toxic polybrominated and polychlorinated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs) when dioxin precursors are present. Therefore, the MC technology was modified for treatment of the PCB and PBDE containing soil including an efficient cooling system which could prevent the formation of PXDD/F during the destruction of PCBs and PBDEs. This is likely relevant for all contaminated soils containing relevant dioxin precursor and need to be considered for treatment of soils with MC and probably other non-combustion technologies.

Graphical abstract

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