Improved Ethanol Sensing Performance of α-MnO2 Nanorods at Room Temperature Enabled through PPy Embedding.

Ethanol is a colorless, highly flammable, volatile organic compound and is a biomarker for fatty liver diseases. So, high-performance and reliable ethanol sensors are the need of the day for biomedical and environmental monitoring applications and drunken driving detection. In this work, we have reported a polypyrrole (PPy)-embedded α-MnO2 nanorod (NR)-based chemiresistive sensor for the selective detection of trace ethanol vapor at room temperature (25 °C). PPy-embedded α-MnO2 NR nanocomposites (MP25, MP50, and MP100) were synthesized by in situ chemical oxidative polymerization of pyrrole followed by mixing of α-MnO2 NR having different weight ratios. The prepared nanocomposites were characterized by various sophisticated instruments such as XRD, FTIR, Raman spectroscopy, BET, FESEM, TEM, EDX, UV-vis spectroscopy, and current-voltage (I-V) measurement. The as-prepared sensor, namely, PPy-embedded α-MnO2 nanorod (MP50), shows the highest response to ethanol vapor with a detection lower limit of 1 ppm at room temperature with rapid response (∼2.39 s) and recovery (∼37.08 s) times associated with at least 60 days stability, excellent selectivity, good repeatability, and reproducibility. The formation of a p-n heterojunction and transfer of charge carriers between PPy and MnO2 nanoparticles are attributed to the enhancement of sensing performance. Thus, the prepared sensor could be potentially applicable to detect ethanol content in alcoholic beverages, diagnose liver disease from exhale breath analysis, and drunken driving detection.

Role of herbivory in shaping the dryland vegetation ecosystem: Linking spiral vegetation patterns and nonlinear, nonlocal grazing.

Self-organized vegetation patterns are an amazing aspect of dryland ecosystems; in addition to being visually appealing, patterns control how these water-deprived systems react to escalating environmental stress. Although there is a wide variety of vegetation patterns, little is known about the mechanisms behind spiral patterns. The well-known models that explain other vegetation patterns such stripes, rings, and fairy circles cannot account for these spirals. Here we have adopted a modeling approach in which the interplay between herbivore grazing and vegetation is found to be the reason why spirals form. To comprehend the nonlinear dependence of grazing on the availability vegetation, we have introduced a grazing term that gets saturated when forage is abundant. To account for the impact of the spatial nonhomogeneity in vegetation layout, it is thought that grazing is dependent on mean vegetation density rather than density at a single site. Results show how the system dynamics is changed fundamentally depending on the different types of grazing response. Incorporation of nonlocality into the herbivore grazing leads to spiral-shaped vegetation patterns only in natural grazing scenarios; however, no patterning is seen in human controlled herbivory. Overall, our research points to the nonlocal, nonlinear grazing behavior of herbivores as one of the major driving forces for the development of spiral patterns.

Facile and Green Synthesis of Novel Fluorescent Carbon Quantum Dots and Their Silver Heterostructure: An In Vitro Anticancer Activity and Imaging on Colorectal Carcinoma.

Carbon dots (CQDs) have been widely investigated as prime candidates for developing a tumor theranostic platform due to their tunable fluorescence emission and excitation, high water solubility, good photostability, and biocompatibility. Among the CQDs, natural CQDs are an emerging class of nanomaterials in the carbon family. Herein, highly fluorescent carbon quantum dots (CQDs) were synthesized from orange juice using a one-step hydrothermal method and characterized by different techniques. After that, CQD/Ag heterostructures were synthesized by the reduction of silver salt, in particular silver nitrate (AgNO3) solution using sodium borohydride (NaBH4) in different ratios. The photostability and characterization of CQD/Ag heterostructures were investigated. At last, a comparative cellular toxicity measurement was done to select the superior CQD/Ag heterostructure in the human colorectal carcinoma (HCT 116) cell line along with the imaging property. The detailed cell death signaling was also observed in the HCT 116 cell line via the ROS-dependent mitochondrial-mediated pathway, where Akt (RAC-α serine/threonine-protein kinase) played a important role.

Effect of nonlocal grazing on dry-land vegetation dynamics.

Dry-land ecosystems have become a matter of grave concern, due to the growing threat of land degradation and bioproductivity loss. Self-organized vegetation patterns are a remarkable characteristic of these ecosystems; apart from being visually captivating, patterns modulate the system response to increasing environmental stress. Empirical studies hinted that herbivory is one the key regulatory mechanisms behind pattern formation and overall ecosystem functioning. However, most of the mathematical models have taken a mean-field strategy to grazing; foraging has been considered to be independent of spatial distribution of vegetation. To this end, an extended version of the celebrated plant-water model due to Klausmeier has been taken as the base here. To encompass the effect of heterogeneous vegetation distribution on foraging intensity and subsequent impact on entire ecosystem, grazing is considered here to depend on spatially weighted average vegetation density instead of density at a particular point. Moreover, varying influence of vegetation at any location over gazing elsewhere is incorporated by choosing a suitable averaging function. A comprehensive analysis demonstrates that inclusion of spatial nonlocality alters the understanding of system dynamics significantly. The grazing ecosystem is found to be more resilient to increasing aridity than it was anticipated to be in earlier studies on nonlocal grazing. The system response to rising environmental pressure is also observed to vary depending on the grazer. Obtained results also suggest the possibility of multistability due to the history dependence of the system response. Overall, this work indicates that the spatial heterogeneity in grazing intensity has a decisive role to play in the functioning of water-limited ecosystems.

Effects of non-local competition on plankton-fish dynamics.

In ecology, the intra- and inter-specific competition between individuals of mobile species for shared resources is mostly non-local; i.e., competition at any spatial position will not only be dependent on population at that position, but also on population in neighboring regions. Therefore, models that assume competition to be restricted to the individuals at that position only are actually oversimplifying a crucial physical process. For the past three decades, researchers have established the necessity of considering spatial non-locality while modeling ecological systems. Despite this ecological importance, studies incorporating this non-local nature of resource competition in an aquatic ecosystem are surprisingly scarce. To this end, the celebrated Scheffer's tri-trophic minimal model has been considered here as a base model due to its efficacy in describing the pelagic ecosystem with least complexity. It is modified into an integro-reaction-diffusion system to include the effect of non-local competition by introducing a weighted spatial average with a suitable influence function. A detailed analysis shows that the non-locality may have a destabilizing effect on underlying nutrient-plankton-fish dynamics. A local system in a stable equilibrium state can lose its stability through spatial Hopf and Turing bifurcations when strength of a non-local interaction is strong enough, which eventually generates a large range of spatial patterns. The relationship between a non-local interaction and fish predation has been established, which shows that fish predation contributes in damping of plankton oscillations. Overall, results obtained here manifest the significance of non-locality in aquatic ecosystems and its possible contribution to the phenomena of "spatial patchiness."

Effect of annealing on the defect-mediated blue phosphorescence in ZnO nanocrystals.

Recently, UV/NUV excitable RGB phosphors with precisely tunable PL emission properties have been in high demand for their suitability in the fabrication of white LEDs. In this paper, we report to have tuned the PL intensity, shade, and color temperature of the defect-mediated blue phosphorescence of ZnO nanopowders by systematic annealing at different temperatures. The ZnO nanopowder was prepared by a facile and cost-effective aqueous solution-precipitation method. The as-synthesized nanopowder was annealed at different temperatures ranging from 150 °C to 850 °C and all these samples were characterized by XRD, FESEM, EDX, BET, Raman spectroscopy, and UV-Vis spectroscopy to have insight into their microstructural, compositional, and band-structure details. Optical studies of the samples were conducted by PL and τ-PL spectroscopy. Color coordinates of the samples were obtained from the CIE plots derived from the PL spectra. The CIE coordinates were further used to calculate the CCT values of the samples. τ-PL spectroscopy was carried out to measure the life-time of the photogenerated electrons. PL studies of the samples revealed that the blue emissions have red, yellow, and blue components originating from crystalline point defects, viz. zinc interstitial (Zni), and oxygen interstitial (Oi). Annealing at different temperatures triggered changes in the defect concentrations leading to the corresponding changes in the intensity, shade, and color temperature of the blue phosphorescence.

Novel multiple phosphorescence in nanostructured zinc oxide and calculations of correlated colour temperature.

The design and development of novel and high quantum efficiency luminescent materials, such as phosphors, having tuneability in properties, have received tremendous interest among scientists. In this paper, we have achieved for the first-time multiple phosphorescence (blue and green) having a life-time of ∼10 µs in nanostructured zinc oxide that was synthesized using an easy and facile sol-gel method. Importantly, the photoluminescence (PL) intensity and the phosphorescence life-time could be tuned by controlling the annealing temperature under a reducing atmosphere. Temperature and atmosphere dependent variation of [VO] and has been interpreted by the detailed thermodynamic analysis of defect chemistry, for the first time. These nanostructured zinc oxide particles being sufficiently large in size (around 160 nm) are extremely stable and expected to show photoluminescence for a longer period of time than nanorods and quantum dots. The quantum yield was found to be as high as 13-15% which is comparable to the order of magnitude of that of quantum dots. The calculated correlated colour temperature is found to be suitable for cool lighting applications.

Acetolactate synthase regulatory subunits play divergent and overlapping roles in branched-chain amino acid synthesis and Arabidopsis development.

BACKGROUND: Branched-chain amino acids (BCAAs) are synthesized by plants, fungi, bacteria, and archaea with plants being the major source of these amino acids in animal diets. Acetolactate synthase (ALS) is the first enzyme in the BCAA synthesis pathway. Although the functional contribution of ALS to BCAA biosynthesis has been extensively characterized, a comprehensive understanding of the regulation of this pathway at the molecular level is still lacking. RESULTS: To characterize the regulatory processes governing ALS activity we utilized several complementary approaches. Using the ALS catalytic protein subunit as bait we performed a yeast two-hybrid (Y2H) screen which resulted in the identification of a set of interacting proteins, two of which (denoted as ALS-INTERACTING PROTEIN1 and 3 [AIP1 and AIP3, respectively]) were found to be evolutionarily conserved orthologues of bacterial feedback-regulatory proteins and therefore implicated in the regulation of ALS activity. To investigate the molecular role AIPs might play in BCAA synthesis in Arabidopsis thaliana, we examined the functional contribution of aip1 and aip3 knockout alleles to plant patterning and development and BCAA synthesis under various growth conditions. Loss-of-function genetic backgrounds involving these two genes exhibited differential aberrant growth responses in valine-, isoleucine-, and sodium chloride-supplemented media. While BCAA synthesis is believed to be localized to the chloroplast, both AIP1 and AIP3 were found to localize to the peroxisome in addition to the chloroplast. Analysis of free amino acid pools in the mutant backgrounds revealed that they differ in the absolute amount of individual BCAAs accumulated and exhibit elevated levels of BCAAs in leaf tissues. Despite the phenotypic differences observed in aip1 and aip3 backgrounds, functional redundancy between these loci was suggested by the finding that aip1/aip3 double knockout mutants are severely developmentally compromised. CONCLUSIONS: Taken together the data suggests that the two regulatory proteins, in conjunction with ALS, have overlapping but distinct functions in BCAA synthesis, and also play a role in pathways unrelated to BCAA synthesis such as sodium-ion homeostasis, extending to broader aspects of patterning and development.

Study of Vitamin B12 deficiency and peripheral neuropathy in metformin-treated early Type 2 diabetes mellitus.

BACKGROUND: Long-term therapy with metformin was shown to decrease the Vitamin B12 level and manifested as peripheral neuropathy. AIM: The aim of this study is to define the prevalence of Vitamin B12 deficiency in early Type 2 diabetic patients (duration ≤5 years or drug treatment ≤3 years) and the relationship among metformin exposure and levels of cobalamin (Cbl), folic acid, and homocysteine (Hcy) with severity of peripheral neuropathy. METHODOLOGY: This is a cross-sectional study involving randomly selected ninety patients (male 56, female 34) between age groups of 35 and 70 years, comparing those who had received >6 months of metformin (Group A) (n = 35) with those without metformin (Group B) (n = 35) and patients taking metformin with other oral hypoglycemic agent (Group C) (n = 20). Comparisons were made clinically, biochemically (serum Cbl, fasting Hcy, and folic acid), and with electrophysiological measures (nerve conduction studies of all four limbs). Comorbidities contributing to neuropathy were excluded from the study. RESULTS: Group A patients (54.28%) were prone to develop peripheral neuropathy comparing Group B (28.57%) and Group C (35%). There was significantly low plasma level of Cbl in Group A (mean 306.314 pg/ml) than in Group B (mean 627.543 pg/ml) and Group C (mean 419.920 pg/ml). There was insignificant low-level plasma folic acid in Group A (16.47 ng/ml) than in Group B (16.81 ng/ml) and Group C (22.50 ng/ml). There was significantly high level of Hcy in Group A (mean 17.35 µmol/L) and Group C (mean 16.99 µmol/L) than in Group B (mean 13.22 µmol/L). Metformin users even for 2 years showed evidence of neuropathy on nerve conduction velocity though their body mass index and postprandial blood sugar were maintained. There was significant difference in between groups regarding plasma Cbl, folic acid, and Hcy level as significance level <0.05 in all three groups (F [2, 87] = 28.1, P = 0.000), (F [2, 87] = 7.43, P = 0.001), (F [2, 87] = 9.76, P = 0.000). Post hoc study shows significant (P < 0.05) lowering of Cbl and Hcy level in Group A (mean = 306.314, standard deviation [SD] = 176.7) than in Group C (mean = 419.92, SD = 208.23) and Group B (mean = 627.543, SD = 168.33). DISCUSSION: Even short-term treatment with metformin causes a decrease in serum Cbl folic acid and increase in Hcy, which leads to peripheral neuropathy in Type 2 diabetes patients. A multicenter study with heterogeneous population would have increased the power of the study. We suggest prophylactic Vitamin B12 and folic acid supplementation or periodical assay in metformin user.

High Precision DNA Modification Analysis of HCG9 in Major Psychosis.

New epigenetic technologies may uncover etiopathogenic mechanisms of major psychosis. In this study, we applied padlock probe-based ultra-deep bisulfite sequencing for fine mapping of modified cytosines of the HLA complex group 9 (nonprotein coding) gene in the postmortem brains of individuals affected with schizophrenia or bipolar disorder and unaffected controls. Significant differences between patients and controls were detected in both CpG and CpH modifications. In addition, we identified epigenetic age effects, DNA modification differences between sense and anti-sense strands, and demonstrated how DNA modification data can be used in clustering of patient populations. Our findings revealed new epigenetic complexities but also highlighted the potential of DNA modification approaches in the search of heterogeneous causes of major psychiatric disease.

DNA modification study of major depressive disorder: beyond locus-by-locus comparisons.

BACKGROUND: Major depressive disorder (MDD) exhibits numerous clinical and molecular features that are consistent with putative epigenetic misregulation. Despite growing interest in epigenetic studies of psychiatric diseases, the methodologies guiding such studies have not been well defined. METHODS: We performed DNA modification analysis in white blood cells from monozygotic twins discordant for MDD, in brain prefrontal cortex, and germline (sperm) samples from affected individuals and control subjects (total N = 304) using 8.1K CpG island microarrays and fine mapping. In addition to the traditional locus-by-locus comparisons, we explored the potential of new analytical approaches in epigenomic studies. RESULTS: In the microarray experiment, we detected a number of nominally significant DNA modification differences in MDD and validated selected targets using bisulfite pyrosequencing. Some MDD epigenetic changes, however, overlapped across brain, blood, and sperm more often than expected by chance. We also demonstrated that stratification for disease severity and age may increase the statistical power of epimutation detection. Finally, a series of new analytical approaches, such as DNA modification networks and machine-learning algorithms using binary and quantitative depression phenotypes, provided additional insights on the epigenetic contributions to MDD. CONCLUSIONS: Mapping epigenetic differences in MDD (and other psychiatric diseases) is a complex task. However, combining traditional and innovative analytical strategies may lead to identification of disease-specific etiopathogenic epimutations.

The dependency of vitamin d status on anthropometric data.

BACKGROUND: Hypovitaminosis D appears to parallel several cardiovascular and pulmonary diseases. However, previous findings cannot be considered conclusive, since the association may have been confounded by different anthropometric variables that were not accounted for. The present cross-sectional study was conducted to investigate the association between important explanatory variables and circulation levels of vitamin D. METHODS: A total of 553 individuals attending the metabolic and medical lifestyle management clinic of the Burdwan district of India were selected from 1289 people by simple random sampling, and information regarding relevant variables and their blood was obtained. Serum 25-hydroxyvitamin (OH) D level and forced expiratory volume in 1 second were measured. Associations between different explanatory variables and circulatory 25(OH) D were analysed in linear regression models. RESULTS: Of the population studied, 53% had insufficient vitamin D levels, while approximately 9% were vitamin D deficient. Variables that significantly associated with lower 25(OH)D levels were obesity, current smoking, forced expiratory volume 1 and depression. CONCLUSION: Lower serum levels of vitamin D were associated with different variables that should be explored in several diseases before a conclusion of hypovitaminosis D is drawn.

Predictors of insulin resistance and metabolic complications in polycystic ovarian syndrome in an eastern Indian population.

The purpose of this study was to assess the predictive values of central obesity and hyperandrogenemia in development of insulin resistance and dyslipidemia in the polycystic ovarian syndrome (PCOS) patients in our region. Differences of fasting blood glucose level, insulin resistance index HOMA-IR, lipid parameters, waist hip ratio (WHR), body mass index, LH/FSH ratio and testosterone levels between 45 PCOS cases and 35 age matched controls were obtained. Strength of association between different parameters in the case group was assayed by Pearson's correlation analysis. Dependence of insulin resistance and WHR on different predictors was assessed by multiple linear regression assay. Total cholesterol, LDL cholesterol, LH, FSH, LH/FSH ratio, WHR and insulin resistance were significantly higher in the case group (p < 0.05). Serum testosterone showed strong correlation with insulin resistance and LH/FSH ratio (r = 0.432 and 0.747, p = 0.01 and 0.001 respectively) in the PCOS patients while WHR and serum testosterone level stood out to be most significant predictors for the insulin resistance (ß = 0.361 and 0.498; p = 0.048 and 0.049 respectively). Hyperandrogenemia and central obesity were the major factors predicting development of insulin resistance and its related metabolic and cardiovascular complications in our PCOS patients. We suggest early monitoring for androgen level and WHR in these patients for predicting an ensuing insulin resistance and modulating the treatment procedure accordingly to minimise future cardiovascular risks.

5-hmC in the brain is abundant in synaptic genes and shows differences at the exon-intron boundary.

The 5-methylcytosine (5-mC) derivative 5-hydroxymethylcytosine (5-hmC) is abundant in the brain for unknown reasons. Here we characterize the genomic distribution of 5-hmC and 5-mC in human and mouse tissues. We assayed 5-hmC by using glucosylation coupled with restriction-enzyme digestion and microarray analysis. We detected 5-hmC enrichment in genes with synapse-related functions in both human and mouse brain. We also identified substantial tissue-specific differential distributions of these DNA modifications at the exon-intron boundary in human and mouse. This boundary change was mainly due to 5-hmC in the brain but due to 5-mC in non-neural contexts. This pattern was replicated in multiple independent data sets and with single-molecule sequencing. Moreover, in human frontal cortex, constitutive exons contained higher levels of 5-hmC relative to alternatively spliced exons. Our study suggests a new role for 5-hmC in RNA splicing and synaptic function in the brain.

Understanding bipolar disorder: the epigenetic perspective.

Bipolar disease (BPD) is a complex major psychiatric disorder that affects between 1% and 2% of the population and exhibits ?85% heritability. This has made BPD an appealing target for genetic studies yet, despite numerous attempts, the genetic basis of this disease remains elusive. Recently, it has come to light that epigenetic factors may also influence the development of BPD. These factors act via stable but reversible modifications of DNA and chromatin structure. In this chapter, we revisit the epidemiological, clinical, and molecular findings in BPD and reanalyze them from the perspective of inherited and acquired epigenetic misregulation. Epigenetic research has great potential to enhance our understanding of the molecular basis of BPD.