Microbial communities in pesticide-contaminated soils in Kyrgyzstan and bioremediation possibilities

Abstract

In Kyrgyzstan, many former storehouses and dump sites for obsolete pesticides exist. In 2009/2010, an inventory and assessment of these sites including risks of environmental hazard has been conducted by FAO and the World Bank. Monitoring revealed high concentration of pesticides listed as persistent organic pollutants (POPs). The purpose of this research was to study the microbial structural complexes of the pesticide-contaminated soils in these dumping zones, and to search for and select microorganism's destructors with cytochrome P450 genes for pesticide degradation. Culture-dependent and culture-independent approaches were used to determine the taxonomic composition of these bacterial communities. The universal primer set for the 16S ribosomal RNA (rRNA) gene and the specific primer set P450R were used to amplify the cytochrome P450 hydroxylase gene. In soils from Suzak A and B and soils from Balykchy dumping sites, the bacteria from the Actinobacteria phylum (Micrococcus genus) were dominant. These bacteria made up 32–47% of the indigenous local microflora; bacteria species from the Pseudomonas genus (Gammaproteobacteria phylum) made up 23% in Suzak, 12% in Balykchy soils. Bacillus species from the Firmicutes phylum were found only in Suzak soils. The 16S rRNA analyses and the specific primer set P450R have revealed bacteria with cytochrome genes which are directly involved in the degradation process of organic carbon compounds. Experiments were carried out to help select active degraders from the bacterial populations isolated and used to degrade Aldrin in laboratory. Active bacterial strains from the Pseudomonas fluorescens and Bacillus polymyxa population were selected which demonstrated high rates of degradation activity on Aldrin.

http://ift.tt/2xeEmRD

Novel mechanisms in immune tolerance to allergens during natural allergen exposure and allergen-specific immunotherapy

Publication date: October 2017
Source:Current Opinion in Immunology, Volume 48
Author(s): Willem van de Veen, Oliver F Wirz, Anna Globinska, Mübeccel Akdis
Allergen-specific immunotherapy (AIT) has been used for more than 100 years as a clinical tolerance-inducing and immune tolerance-inducing therapy for allergic diseases and represents a potentially curative method of treatment. AIT functions through multiple mechanisms including early desensitization of basophils and mast cells, regulating T-cell and B-cell responses, changing antibody isotypes, and decreasing activation, mediator release and affected tissue migration of eosinophils, basophils, and mast cells. Similar molecular and cellular mechanisms have been observed in subcutaneous AIT, sublingual AIT and peptide immunotherapy as well as natural tolerance to high doses of allergen exposure in beekeepers and cat owners.



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Immune monitoring for precision medicine in allergy and asthma

Publication date: October 2017
Source:Current Opinion in Immunology, Volume 48
Author(s): Scott Dexter Boyd, Ramona Amy Hoh, Kari Christine Nadeau, Stephen Joseph Galli
'Precision Medicine' embodies the analyses of extensive data collected from patients and their environments to identify and apply patient-specific prophylactic strategies and medical treatments to improve clinical outcomes and healthcare cost-effectiveness. Many new methods have been developed for evaluating the activity of the human immune system. Such 'immune monitoring' approaches are now being used in studies of allergy and asthma in the hope of identifying better correlates of disease status, predictors of therapeutic outcomes, and potential side-effects of treatment. Together with analyses of family histories, genetic and other biometric data, and measurements of exposures to environmental and other risk factors for developing or exacerbating disease, immune monitoring approaches promise to enable 'Precision Medicine' for allergic diseases and asthma.



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Air quality impacts of projections of natural gas-fired distributed generation

Publication date: November 2017
Source:Atmospheric Environment, Volume 168
Author(s): Jeremy R. Horne, Marc Carreras-Sospedra, Donald Dabdub, Paul Lemar, Uarporn Nopmongcol, Tejas Shah, Greg Yarwood, David Young, Stephanie L. Shaw, Eladio M. Knipping
This study assesses the potential impacts on emissions and air quality from the increased adoption of natural gas-fired distributed generation of electricity (DG), including displacement of power from central power generation, in the contiguous United States. The study includes four major tasks: (1) modeling of distributed generation market penetration; (2) modeling of central power generation systems; (3) modeling of spatially and temporally resolved emissions; and (4) photochemical grid modeling to evaluate the potential air quality impacts of increased DG penetration, which includes both power-only DG and combined heat and power (CHP) units, for 2030. Low and high DG penetration scenarios estimate the largest penetration of future DG units in three regions – New England, New York, and California. Projections of DG penetration in the contiguous United States estimate 6.3 GW and 24 GW of market adoption in 2030 for the low DG penetration and high DG penetration scenarios, respectively. High DG penetration (all of which is natural gas-fired) serves to offset 8 GW of new natural gas combined cycle (NGCC) units, and 19 GW of solar photovoltaic (PV) installations by 2030. In all scenarios, air quality in the central United States and the northwest remains unaffected as there is little to no DG penetration in those states. California and several states in the northeast are the most impacted by emissions from DG units. Peak increases in maximum daily 8-h average ozone concentrations exceed 5 ppb, which may impede attainment of ambient air quality standards. Overall, air quality impacts from DG vary greatly based on meteorological conditions, proximity to emissions sources, the number and type of DG installations, and the emissions factors used for DG units.



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Validating modelled data on major and trace element deposition in southern Germany using Sphagnum moss

Publication date: October 2017
Source:Atmospheric Environment, Volume 167
Author(s): Heike Kempter, Michael Krachler, William Shotyk, Claudio Zaccone
Sphagnum mosses were collected from four ombrotrophic bogs in two regions of southern Germany: Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and, one year later, plant matter was harvested and productivity determined. Major and trace element concentrations (Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Rb, Sb, Sc, Sr, Th, Ti, Tl, U, V, Zn) were determined in acid digests using sector field ICP-MS. Up to 12 samples (40 × 40 cm) were collected per site, and 6–10 sites investigated per bog. Variation in element accumulation rates within a bog is mostly the result of the annual production rate of the Sphagnum mosses which masks not only the impact of site effects, such as microtopography and the presence of dwarf trees, but also local and regional conditions, including land use in the surrounding area, topography, etc. The difference in productivity between peat bogs results in distinctly higher element accumulation rates at the NBF bogs compared to those from OB for all studied elements. The comparison with the European Monitoring and Evaluation Program (EMEP; wet-only and total deposition) and Modelling of Air Pollutants and Ecosystem Impact (MAPESI; total deposition) data shows that accumulation rates obtained using Sphagnum are in the same range of published values for direct measurements of atmospheric deposition of As, Cd, Cu, Co, Pb, and V in both regions. The accordance is very dependent on how atmospheric deposition rates were obtained, as different models to calculate the deposition rates may yield different fluxes even for the same region. In future studies of atmospheric deposition of trace metals, both Sphagnum moss and deposition collectors have to be used on the same peat bog and results compared. Antimony, however, shows considerable discrepancy, because it is either under-estimated by Sphagnum moss or over-estimated by both atmospheric deposition models. Atmospheric deposition data obtained from sampling in open fields is unlikely to always perfectly match data obtained using living Sphagnum moss from bogs. In fact, plant uptake and biochemical utilization by living moss may affect accumulation rates of those elements that are essential for plant nutrition (macro and micronutrients), which is clearly seen in the data presented here for Mn, Fe and Zn. Furthermore, Sphagnum moss is a unique receptor, with its characteristic roughness and chemical complexity. These two aspects, combined with conditions found on the bog surface (variations in microtopography, shrubs, trees, wetness, snow cover, etc.), result in a unique type of interception and retention. Despite all these factors, the comparison with modelled data shows that Sphagnum moss is a good indicator of atmospheric deposition at least in a semi-quantitative manner and certainly reflects inputs to terrestrial ecosystems.



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Recent changes in the oxidized to reduced nitrogen ratio in atmospheric precipitation

Publication date: October 2017
Source:Atmospheric Environment, Volume 167
Author(s): Iwona Kurzyca, Marcin Frankowski
In this study, the characteristics of precipitation in terms of various nitrogen forms (NO3⁻, NO2⁻, NH4⁺, Norganic, Ntotal) is presented. The samples were collected in the areas of different anthropogenic pressure (urban area vs. ecologically protected woodland area, ∼30 km distant from each other; Wielkopolska region, Poland). Based on the Nox and Nred emission profiles (Nox/Nred ratio), temporal and spatial comparison was carried out. For both sites, during a decade of observation, more than 60% of samples had higher contribution of N-NH4⁺ than N-NO3^-, the amount of N-NO2^- was negligible, and organic nitrogen amounted to 30% of total nitrogen content which varied up to 16 mg/l. The precipitation events w ith high concentration of nitrogen species were investigated in terms of possible local and remote sources of nitrogen (synoptic meteorology), to indicate the areas which can act as potential sources of N-compounds. Based on the chemometric analysis, it was found that Nred implies Nox and vice versa, due to interactions between them in the atmosphere. Taking into account the analysis of precipitation occurring simultaneously in both locations (about 50% of all rainfall episodes), it was observed that such factor as anthropogenic pressure differentiates but does not determine the chemical composition of precipitation in the investigated areas (urban vs. woodland area; distance of ∼30 km). Thermodynamics of the atmosphere had a significant impact on concentrations of N-NO3^- and N-NH4⁺ in precipitation, as well as the circulation of air masses and remote N sources responsible for transboundary inflow of pollutants.



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Role of Human DNA2 (hDNA2) as a Potential Target for Cancer and other Diseases: A Systematic Review

Publication date: Available online 6 September 2017
Source:DNA Repair
Author(s): Pan-Pan Jia, Muhammad Junaid, Yan-Bo Ma, Farooq Ahmad, Yong-Fang Jia, Wei-Guo Li, De-Sheng Pei
DNA nuclease/helicase 2 (DNA2), a multi-functional protein protecting the high fidelity of genomic transmission, plays critical roles in DNA replication and repair processes. In the maturation of Okazaki fragments, DNA2 acts synergistically with other enzymes to cleave the DNA-RNA primer flaps via different pathways. DNA2 is also involved in the stability of mitochondrial DNA and the maintenance of telomeres. Moreover, DNA2 potentially participates in controlling the cell cycle by repairing the DNA replication faults at main checkpoints. In addition, previous evidences demonstrated that DNA2 also functions in the repair process of DNA damages, such as base excision repair (BER). Currently, large studies revealed the structures and functions of DNA2 in prokaryotes and unicellular eukaryotes, such as bacteria and yeast. However, the studies that highlighted the functions of human DNA2 (hDNA2) and the relationships with other multifunctional proteins are still elusive, and more precise investigations are immensely needed. Therefore, this review mainly encompasses the key functions of DNA2 in human cells with various aspects, especially focusing on the genome integrity, and also generalizes the recent insights to the mechanisms related to the occurrence of cancer and other diseases potentially linked to the mutations in DNA2.



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The NO-heme signaling hypothesis

Publication date: November 2017
Source:Free Radical Biology and Medicine, Volume 112
Author(s): Andrei L. Kleschyov
While the biological role of nitric oxide (NO) synthase (NOS) is appreciated, several fundamental aspects of the NOS/NO-related signaling pathway(s) remain incompletely understood. Canonically, the NOS-derived NO diffuses through the (inter)cellular milieu to bind the prosthetic ferro(Fe²⁺)-heme group of the soluble guanylyl cyclase (sGC). The formation of ternary NO-ferroheme-sGC complex results in the enzyme activation and accelerated production of the second messenger, cyclic GMP. This paper argues that cells dynamically generate mobile/exchangeable NO-ferroheme species, which activate sGC and regulate the function of some other biomolecules. In contrast to free NO, the mobile NO-ferroheme may ensure safe, efficient and coordinated delivery of the signal within and between cells. The NO-heme signaling may contribute to a number of NOS/NO-related phenomena (e.g. nitrite bioactivity, selective protein S-(N-)nitrosation, endothelium and erythrocyte-dependent vasodilation, some neural and immune NOS functions) and predicts new NO-related discoveries, diagnostics and therapeutics.

Graphical abstract

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Could lung cancer exosomes induce apoptosis of natural killer cells through the p75NTR–proNGF– sortilin axis?

Publication date: Available online 6 September 2017
Source:Medical Hypotheses
Author(s): Ming-Chuang Zhu, Peng Xiong, Guo-Liang Li, Min Zhu
Lung cancer is the leading cause of cancer-related death worldwide. Tumor exosomes play an important role in the development of lung cancer. Previous studies indicated that tumor exosomes derived from lung cancer cells contained abundant sortilin. Sortilin is a member of the vacuolar protein sorting 10 protein (VPS10P) family of receptors that act as co-receptors for p75NTR and play an independent role in cell death induced by proNGF. Recently, a study showed that proNGF could mediate the death of natural killer (NK) cells through binding to the p75NTR–sortilin complex. However, it has not been reported, to our knowledge, that lung cancer cells induce NK cell apoptosis through a p75NTR–proNGF–sortilin mechanism. As a secreted protein, lung cancer cells may release some proNGF into the tumor microenvironment. We therefore hypothesized that lung cancer cells may promote the apoptosis of NK cells through releasing exosomal sortilin and proNGF. To test this hypothesis, experiments involving the production of exosomal sortilin and proNGF in lung cancer cells and the expression of p75NTR in NK cells are required based upon previously established experiments using fluorescent components. Such experiments may provide insight into the potential mechanism by which lung cancer cells promote apoptosis of NK cells through a p75NTR– proNGF–sortilin pathway.



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Peritoneal Dialysis: The Unique Features by Compartmental Delivery of Renal Replacement Therapy

Publication date: Available online 7 September 2017
Source:Medical Hypotheses
Author(s): Tibor Fülöp, Lajos Zsom, Mihály B. Tapolyai, Miklos Z. Molnar, Sohail Abdul Salim, István Arany, Mehrdad Hamrahian, László Rosivall
Despite decades of research, the clinical efficacy of peritoneal dialysis (PD) remains enigmatic. We may wonder why the modality fail in some patients but perhaps the more proper question would be, why it works in so many? We know that the contribution of residual renal function (RRF), more so than in hemodialysis, is critically important to the well-being of many of the patients. Unique features of the modality include the relatively low volume of dialysate fluid needed to provide effective uremic control and the disproportionate tendency for both hypokalemia and hypoalbuminemia, when compared to hemodialysis. It is currently believed that most uremic toxins are generated on the interface of human and bacterial structures in the gastrointestinal tract, the intestinal biota. PD offers disproportionate removal of these toxins upon "first-pass", i.e., via PD fluid exchanges before reaching the systemic circulation beyond the gastrointestinal compartment. Studies examining the net removal gradient of protein-bound uremic toxins during PD are scarce, whereas RRF receives considerably more attention without effective interventions being developed to preserve it. We propose an alternative view on PD, emphasizing the modality's compartmental nature, both for its benefits and the limitations.



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Functional group influences on the reactive azo dye decolorization performance by electrochemical oxidation and electro-Fenton technologies

Abstract

Electrochemical water treatment technologies are highly promising to achieve complete decolorization of dyebath effluents, as demonstrated by several studies reported in the literature. However, these works are focused on the treatment of one model pollutant and generalize the performances of the processes which are not transposable since they depend on the pollutant treated. Thus, in the present study, we evaluate, for the first time, the influence of different functional groups that modify the dye structure on the electrochemical process decolorization performance. The textile azo dyes Reactive Orange 16, Reactive Violet 4, Reactive Red 228, and Reactive Black 5 have been selected because they present the same molecular basis structure with different functional groups. The results demonstrate that the functional groups that reduce the nucleophilicity of the pollutant hinder the electrophilic attack of electrogenerated hydroxyl radical. Thereby, the overall decolorization efficiency is consequently reduced as well as the decolorization rate. Moreover, the presence of an additional chromophore azo bond in the molecule enhances the recalcitrant character of the azo dyes as pollutants. The formation of a larger and more stable conjugated π system increases the activation energy required for the electrophyilic attack of ^•OH, affecting the performance of electrochemical technologies on effluent decolorization.

http://ift.tt/2gLsoo8

Using the chemical mass balance model to estimate VOC source contributions in newly built timber frame houses: a case study

Abstract

Basing on the material emission data obtained in a test chamber, chemical mass balance (CMB) was used to assess the source apportionment of volatile organic compound (VOC) concentrations in three newly built timber frame houses. CMB has been proven to be able to discriminate the source contributions for two contrasted environmental conditions (with and without ventilation). The shutdown of the ventilation system caused an increase in the VOC concentrations due to the increased contribution of indoor surface materials like the door material and furniture explaining together over 65% of total VOCs. While the increase in formaldehyde concentration is mainly due to furniture (contribution of 70%), the increase in α-pinene concentration is almost exclusively attributable to the emission of door material (up to 84%). The apportionment of VOC source contributions appears as highly dependent on the position of source materials in the building (surface materials or internal materials) and the ventilation conditions explaining that the concentrations of compounds after the shutdown of ventilation system do not increase in equivalent proportion. Knowledge of indoor sources and its contributions in real conditions may help in the selection of materials and in the improvement of construction operations to reduce the indoor air pollution.

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Clinical and pathologic predictors of central lymph node metastasis in papillary thyroid microcarcinoma: a retrospective cohort study

Abstract

Objective

To identify the clinical and pathological predictors of central lymph node metastasis (CLNM) in patients with clinically lymph node-negative papillary thyroid microcarcinoma (PTMC).

Materials and methods

Data pertaining to 541 clinically lymph node-negative PTMC patients who underwent thyroid surgery at the Shanghai General Hospital between January 2010 and December 2013 were retrospectively analyzed. According to histopathological evidence of central lymph node involvement, patients were divided into central lymph node metastasis (CLNM)-positive and CLNM-negative groups; risk factors for CLNM were identified statistically.

Results

LNM was found in 148 (27.4%) patients. Gender (P = 0.002), age (P < 0.001), tumor size (P < 0.001), multifocality (P < 0.001), and extrathyroidal extension (P < 0.001) were significantly different between CLNM-positive and CLNM-negative groups. On multivariate analyses, male sex (odds ratio [OR] = 2.656), age <45 years (OR = 4.184), tumor size >0.575 cm (OR = 2.105), gross extrathyroidal extension (OR = 14.605) and multifocality (OR = 2.084) were independent risk factors for CLNM. Among patients who did not have any of these five risk factors, only 3.9% were found to have CLNM.

Conclusions

A relatively high prevalence of CLNM was observed in patients with clinically lymph node-negative PTMC. CLNM was associated with male sex, younger age, larger tumor size, extrathyroidal extension and multifocal PTMC.

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Increased left prefrontal brain perfusion after MRI compatible tDCS attenuates momentary ruminative self-referential thoughts

Publication date: Available online 6 September 2017
Source:Brain Stimulation
Author(s): Chris Baeken, Jonathan Remue, Marie-Anne Vanderhasselt, Andre R. Brunoni, Sara De Witte, Romain Duprat, Ernst H.W. Koster, Rudi De Raedt, Guo-Rong Wu
BackgroundTranscranial direct current stimulation (tDCS) is a non-invasive electrical stimulation technique, assumed to influence cognition and emotional processing. Objective: However, it is unclear how tDCS influences spontaneous cognitive processes such as momentary self-referential thoughts on the neuronal level.MethodsForty healthy female volunteers participated in a single session sham-controlled crossover tDCS study while being in the MRI scanner. We measured brain perfusion (arterial spin labeling) just before and just after tDCS. Before and after the stimulation procedure, participants were scored on mood (visual analogue scales) and on the Momentary Ruminative Self-focus Inventory (MRSI). We performed a 1.5 mA, 20-min, anodal left dorsolateral prefrontal cortex, cathodal right supraorbital stimulation.ResultsOne sham-controlled tDCS session did not result in subjective mood changes. However, as compared to before, MRSI scores significantly decreased only after active tDCS. Regression analysis revealed that this reduction in momentary ruminative self-referential thoughts was related to tDCS-related increases in left prefrontal cortical perfusion. tDCS decreased momentary self-referential thoughts, which was associated with increasing perfusion in the left prefrontal cortex.ConclusionOur findings are in line with the hypothesis that tDCS of the DLPFC attenuates ruminative processes.



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Clinical and electrophysiological outcomes of deep TMS over the medial prefrontal and anterior cingulate cortices in OCD patients

Publication date: Available online 6 September 2017
Source:Brain Stimulation
Author(s): Lior Carmi, Uri Alyagon, Noam Barnea-Ygael, Joseph Zohar, Reuven Dar, Abraham Zangen
BackgroundObsessive Compulsive Disorder (OCD) is a chronic and disabling disorder with poor response to pharmacological treatments. Converging evidences suggest that OCD patients suffer from dysfunction of the cortico-striato-thalamo-cortical (CSTC) circuit, including in the medial prefrontal cortex (mPFC) and the anterior cingulate cortex (ACC).ObjectiveTo examine whether modulation of mPFC-ACC activity by deep transcranial magnetic stimulation (DTMS) affects OCD symptoms.MethodsTreatment resistant OCD participants were treated with either high-frequency (HF; 20 Hz), low-frequency (LF; 1 Hz), or sham DTMS of the mPFC and ACC for five weeks, in a double-blinded manner. All treatments were administered following symptoms provocation, and EEG measurements during a Stroop task were acquired to examine changes in error-related activity. Clinical response to treatment was determined using the Yale-Brown-Obsessive-Compulsive Scale (YBOCS).ResultsInterim analysis revealed that YBOCS scores were significantly improved following HF (n = 7), but not LF stimulation (n = 8), compared to sham (n = 8), and thus recruitment for the LF group was terminated. Following completion of the study, the response rate in the HF group (n = 18) was significantly higher than that of the sham group (n = 15) for at least one month following the end of the treatment. Notably, the clinical response in the HF group correlated with increased Error Related Negativity (ERN) in the Stroop task, an electrophysiological component that is attributed to ACC activity.ConclusionHF DTMS over the mPFC-ACC alleviates OCD symptoms and may be used as a novel therapeutic intervention. Notwithstanding alternative explanations, this may stem from DTMS ability to directly modify ACC activity.



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Prefrontal versus motor cortex transcranial direct current stimulation (tDCS) effects on post-surgical opioid use

Publication date: Available online 6 September 2017
Source:Brain Stimulation
Author(s): Jeffrey J. Borckardt, Scott T. Reeves, Cole Milliken, Brittan Carter, Thomas I. Epperson, Ryan J. Gunselman, Alok Madan, H. Del Schutte, Harry A. Demos, Mark S. George
BackgroundPain is often a complaint that precedes total knee arthroplasty (TKA), however the procedure itself is associated with considerable post-operative pain lasting days to weeks which can predict longer-term surgical outcomes. Previously, we reported significant opioid-sparing effects of motor cortex transcranial direct current stimulation from a single-blind trial. In the present study, we used double-blind methodology to compare motor cortex tDCS and prefrontal cortex tDCS to both sham and active-control (active electrodes over non-pain modulating brain areas) tDCS.Methods58 patients undergoing unilateral TKA were randomly assigned to receive 4 20-min sessions (a total of 80 min) of tDCS (2 mA) post-surgery with electrodes placed to create 4 groups: 1) MOTOR (n = 14); anode-motor/cathode-right prefrontal, 2) PREFRONTAL (n = 16); anode-left-prefrontal/cathode-right-sensory, 3) ACTIVE-CONTROL (n = 15); anode-left-temporal-occipital junction/cathode-medial-anterior-premotor-area, and 4) SHAM (n = 13); 0 mA-current stimulation using placements 1 or 2. Patient controlled analgesia (PCA; hydromorphone) use was tracked during the ∼72-h post-surgery.ResultsPatients in the sham group and the active-control group used 15.4 mg (SD = 14.1) and 16.0 mg (SD = 9.7) of PCA hydromorphone respectively. There was no difference between the slopes of the cumulative PCA usage curves between these two groups (p = 0.25; ns). Patients in the prefrontal tDCS group used an average of 11.7 mg (SD = 5.0) of PCA hydromporhone, and the slope of the cumulative PCA usage curve was significantly lower than sham (p < 0.0001). However, patients in the motor tDCS group used an average of 19.6 mg (SD = 11.9) hydromorphone and the slope of the PCA use curve was significantly higher than sham (p < 0.0001).ConclusionsResults from this double-blind cortical-target-optimization study suggest that anodal transcranial direct current stimulation (tDCS) over the left prefrontal cortex may be a reasonable approach to reducing post-TKA opioid requirements. Given the unexpected finding that motor cortex failed to produce an opioid sparing effect in this follow-up trial, further research in the area of post-operative cortical stimulation is still needed.



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Optimization of epidural cortical stimulation for treatment-resistant depression

Publication date: Available online 6 September 2017
Source:Brain Stimulation
Author(s): Nolan R. Williams, Brandon S. Bentzley, Thomas Hopkins, Jaspreet Pannu, Gregory L. Sahlem, Istvan Takacs, Mark S. George, Ziad Nahas, Edward Baron Short




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Hypomineralised second primary molars: prevalence, defect characteristics and relationship with dental caries in Melbourne preschool children

Abstract

Background

Dental caries and enamel defects (DDE) are prevalent amongst children. The presence of DDEs, especially enamel hypomineralisation, may increase caries experience in those at increased caries-risk. The reported prevalence of hypomineralised second primary molars (HSPM) is 2.7% - 21.8%, although the occurrence in Australian children remains unknown. These HSPM represent a potential predictive factor for molar-incisor hypomineralisation (MIH).

Methods

In total, 623 three to five-year-old children from 30 randomly selected kindergartens participated. The HSPM were recorded using an index combining the EAPD MIH Judgment Criteria and modified DDE Index. Caries was recorded using International Caries Detection and Assessment System criteria.

Results

In total, 144 HSPM were observed in 88/623 (14.1%) children, a tooth-level prevalence of 5.8%. The prevalence of dentinal carious lesions was 13.2%, and caries prevalence (d_2-6mft > 0) was 36.4%. Cavitated carious lesions affected 30.7% of HSPM.

Conclusions

The relationship between an increase in HSPM lesion extent and increasing number of HSPM per child was statistically significant. A positive association between HSPM severity and extent at tooth-level existed (p < 0.05). There was a positive relationship between the extent of HSPM and carious lesion severity (p < 0.05). In this population, children with HSPM did not have overall greater caries experience than unaffected children.

This article is protected by copyright. All rights reserved.

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Electrodeposition mechanism of quaternary compounds Cu2ZnSnS4: Effect of the additives

Publication date: 1 January 2018
Source:Applied Surface Science, Volume 427, Part A
Author(s): Aiyue Tang, Zhilin Li, Feng Wang, Meiling Dou, Jingjun Liu, Jing Ji, Ye Song
The electrodeposition mechanism of pure phase Cu2ZnSnS4 (CZTS) thin film with subsequent annealing was investigated in detail. An electrolyte design principle of quaternary compounds was proposed. The complex ions of Cu(H2C6H5O7)⁺, Cu2(C6H5O7)⁺, Zn(C4H5O6)⁺, Sn(H2C6H5O7)⁺ and Sn2(C6H5O7)⁺, which influenced the reduction process and played important roles in co-deposition, were identified by UV spectra. Electrochemical studies indicated that trisodium citrate and tartaric acid could narrow the co-deposition potential range of the four elements to −0.8V to −1.2V (vs. SCE). The cause was the synergetic effect that trisodium citrate inhibited the reduction of Cu²⁺ and Sn²⁺ and tartaric acid promoted the reduction of Zn²⁺. The reduction of S2O3²⁻ was mainly attributed to the induction effect of the metallic ions, and the H⁺ dissociated from tartaric acid could also promote the cathode process of S2O3²⁻. The reaction mechanism could be summarized as the following steps: (I) Cu(H2C6H5O7)⁺, Cu2(C6H5O7)⁺→Cu, Sn(H2C6H5O7)⁺, Sn2(C6H5O7)⁺→Sn, Zn(C4H5O6)⁺→Zn; (II) the desorption of (H2C6H5O7)⁻ and (C6H5O7)⁻, and the reduction of S2O3²⁻ induced by metallic ions and H⁺. The mechanism studies provided a path of electrolyte design for multicomponent compounds.



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C-terminal hydrazide modification changes the spinal antinociceptive profiles of endomorphins in mice

Publication date: Available online 6 September 2017
Source:Peptides
Author(s): Chang-lin Wang, Dai-jun Yang, Bi-yu Yuan, Yu Wang
Previously, we have demonstrated that endomorphins (EMs) analogs with C-terminal hydrazide modification retained the μ-opioid receptor affinity and selectivity, and exhibited potent antinociception after intracerebroventricular (i.c.v.) administration. In the present study, we extended our studies to evaluate the antinociceptive profiles of EMs and their analogs EM-1-NHNH2, EM-2-NHNH2 given spinally in the radiant heat paw withdrawal test. Following intrathecal (i.t.) administration, EM-1, EM-2, EM-1-NHNH2 and EM-2-NHNH2 dose-dependently increased the latency for paw withdrawal response. EM-1-NHNH2 displayed the highest antinociceptive effects, with the ED50 values being 1.63 nmol, more potent than the parent EM-1 (1.96 nmol), but with no significant difference. By contrast, the analgesic activities of EM-2 and its analog EM-2-NHNH2 were almost equivalent (P>0.05). Naloxone and β-funaltrexamine (β-FNA) almost completely attenuated the antinociceptive effects of EMs and their analogs EM-1-NHNH2, EM-2-NHNH2 (10 nmol, i.t.), indicating the involvement of μ-opioid receptors. Notably, the antinociception of EM-1 was not significantly antagonized by naloxonazine, a selective μ1-opioid receptor antagonist, but partially reversed the effects of EM-2, suggesting that EM-1 and EM-2 may produce antinociception through distinct μ1- and μ2-opioid receptor subtypes. Moreover, naloxonazine didn't significantly block the antinociceptive effects of EM-1-NHNH2 and EM-2-NHNH2, and nor-BNI, the κ-opioid receptor antagonist, attenuated the analgesic effects of EM-2, but not EM-1, EM-1-NHNH2 or EM-2-NHNH2. These results indicated that C-terminal amide to hydrazide conversion changed the antinociceptive opioid mechanisms of EM-2 but not EM-1 at the spinal level. Herein, the acute antinociceptive tolerance were further determined and compared. EM-1-NHNH2 and EM-2-NHNH2 shifted the dose-response curve rightward by only 2.8 and 1.5-fold as determined by tolerance ratio, whereas EM-1 and EM-2 by 3.4 and 4.6-fold, respectively, indicating substantially reduced antinociceptive tolerance. The present study demonstrated that C-terminal hydrazide modification changes the spinal antinociceptive profiles of EMs.



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