644 research outputs found
Bacterial and Heavy Metals Analyses in Fish at Shawaka Area of Tigris River
This study was conducted from October to December 2012. 35 fish were collected from the Shawaka area of the Tigris river for quality analyses using bacteriological and chemical parameters. Results of bacteriological analysis showed that the total viable bacteria count in the fish gut, skin and gill were ranged from 35.35×103 - 6×103 cfu/g, 34.9×103 -21×103 cfu/g and 30.1×103 - 1.9×103 cfu/g respectiveluy. 151 bacterial isolates were obtained and identified into 14 genera (13 Gram negative bacteria + one Gram positive bacteria). The predominant bacteria from different organs were Staphylococcus spp., E. coli, Proteus spp., Citrobacter spp., Enterobacter spp. respectively. The results of study indicated that most fish samples were polluted with high levels of heavy metal Pb, Cd and Hg. Concentration of these heavy metals exceed limits for the fish recommended by the World Health Organization (WHO) and the Centre for Environment, Fisheries and Aquaculture Science (CEFAS). Key word: Tigris river, Fish, Bacteria, Heavy Metal
Dyadic Synchrony and Responsiveness in the First Year: Associations with Autism Risk
In the first year of life, the ability to engage in sustained synchronous interactions develops as infants learn to match social partner behaviors and sequentially regulate their behaviors in response to others. Difficulties developing competence in these early social building blocks can impact later language skills, joint attention, and emotion regulation. For children at elevated risk for autism spectrum disorder (ASD), early dyadic synchrony and responsiveness difficulties may be indicative of emerging ASD and/or developmental concerns. As part of a prospective developmental monitoring study, infant siblings of children with ASD (high-risk group n = 104) or typical development (low-risk group n = 71), and their mothers completed a standardized play task when infants were 6, 9, and/or 12 months of age. These interactions were coded for the frequency and duration of infant and mother gaze, positive affect, and vocalizations, respectively. Using these codes, theory-driven composites were created to index dyadic synchrony and infant/maternal responsiveness. Multilevel models revealed significant risk group differences in dyadic synchrony and infant responsiveness by 12 months of age. In addition, high-risk infants with higher dyadic synchrony and infant responsiveness at 12 months received significantly higher receptive and expressive language scores at 36 months. The findings of the present study highlight that promoting dyadic synchrony and responsiveness may aid in advancing optimal development in children at elevated risk for autism. Lay Summary: In families raising children with an autism spectrum disorder (ASD), younger siblings are at elevated risks for social communication difficulties. The present study explored whether social-communication differences were evident during a parent–child play task at 6, 9, and 12 months of age. For infant siblings of children with ASD, social differences during play were observed by 12 months of age and may inform ongoing monitoring and intervention efforts
Spacers to improve performance and porosity of graphene based polymer electrolyte fuel cells
Graphene has been suggested as a potential support material to replace commercial carbon black due to its carbon corrosion resistance. However, graphene-based electrodes typically perform poorly in MEA testing due to restacking of the graphitic sheets. In this study we investigate the introduction of carbon black and their effects on the porosity and current density of graphene-based supports
Functional divergence in the role of N-linked glycosylation in smoothened signaling
The G protein-coupled receptor (GPCR) Smoothened (Smo) is the requisite signal transducer of the evolutionarily conserved Hedgehog (Hh) pathway. Although aspects of Smo signaling are conserved from Drosophila to vertebrates, significant differences have evolved. These include changes in its active sub-cellular localization, and the ability of vertebrate Smo to induce distinct G protein-dependent and independent signals in response to ligand. Whereas the canonical Smo signal to Gli transcriptional effectors occurs in a G protein-independent manner, its non-canonical signal employs Gαi. Whether vertebrate Smo can selectively bias its signal between these routes is not yet known. N-linked glycosylation is a post-translational modification that can influence GPCR trafficking, ligand responsiveness and signal output. Smo proteins in Drosophila and vertebrate systems harbor N-linked glycans, but their role in Smo signaling has not been established. Herein, we present a comprehensive analysis of Drosophila and murine Smo glycosylation that supports a functional divergence in the contribution of N-linked glycans to signaling. Of the seven predicted glycan acceptor sites in Drosophila Smo, one is essential. Loss of N-glycosylation at this site disrupted Smo trafficking and attenuated its signaling capability. In stark contrast, we found that all four predicted N-glycosylation sites on murine Smo were dispensable for proper trafficking, agonist binding and canonical signal induction. However, the under-glycosylated protein was compromised in its ability to induce a non-canonical signal through Gαi, providing for the first time evidence that Smo can bias its signal and that a post-translational modification can impact this process. As such, we postulate a profound shift in N-glycan function from affecting Smo ER exit in flies to influencing its signal output in mice
Quantum Correlations in NMR systems
In conventional NMR experiments, the Zeeman energy gaps of the nuclear spin
ensembles are much lower than their thermal energies, and accordingly exhibit
tiny polarizations. Generally such low-purity quantum states are devoid of
quantum entanglement. However, there exist certain nonclassical correlations
which can be observed even in such systems. In this chapter, we discuss three
such quantum correlations, namely, quantum contextuality, Leggett-Garg temporal
correlations, and quantum discord. In each case, we provide a brief theoretical
background and then describe some results from NMR experiments.Comment: 21 pages, 7 figure
Evolutionary Emergence of microRNAs in Human Embryonic Stem Cells
Human embryonic stem (hES) cells have unique abilities to divide indefinitely without differentiating and potential to differentiate into more than 200 cell types. These properties make hES cells an ideal model system for understanding early human development and for regenerative medicine. Molecular mechanisms including cellular signaling and transcriptional regulation play important roles in hES cell differentiation. However, very little information is available on posttranscriptional regulation of hES cell pluripotency, self-renewal, and early decisions about cell fate. microRNAs (miRNAs), 22-nt long non-coding small RNAs found in plants and animals, regulate gene expression by targeting mRNAs for cleavage or translation repression. In hES cells we found that 276 miRNAs were expressed; of these, a set of 30 miRNAs had significantly changed expression during differentiation. Using a representative example, miR-302b, we show that miRNAs in human ES cells assemble into a bona fide RISC that contains Ago2 and can specifically cleave perfectly matched target RNA. Our results demonstrate that human ES cell differentiation is accompanied by changes in the expression of a unique set of miRNAs, providing a glimpse of a new molecular circuitry that may regulate early development in humans. Chromosomes 19 and X contained 98 and 40 miRNA genes, respectively, indicating that majority of miRNA genes in hES cells were expressed from these two chromosomes. Strikingly, distribution analysis of miRNA gene loci across six species including dog, rat, mouse, rhesus, chimpanzee, and human showed that miRNA genes encoded in chromosome 19 were drastically increased in chimpanzees and humans while miRNA gene loci on other chrosmomes were decreased as compared with dog, rat, and mouse. Comparative genomic studies showed 99% conservation of chromosome 19 miRNA genes between chimpanzees and humans. Together, these findings reveal the evolutionary emergence, ∼5 million years ago, of miRNAs involved in regulating early human development. One could imagine that this burst of miRNA gene clusters at specific chromosomes was part of an evolutionary event during species divergence
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015
SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
Standards for the Characterization of Endurance in Resistive Switching Devices
Resistive switching (RS) devices are emerging electronic components that could have applications in multiple types of integrated circuits, including electronic memories, true random number generators, radiofrequency switches, neuromorphic vision sensors, and artificial neural networks. The main factor hindering the massive employment of RS devices in commercial circuits is related to variability and reliability issues, which are usually evaluated through switching endurance tests. However, we note that most studies that claimed high endurances >106 cycles were based on resistance versus cycle plots that contain very few data points (in many cases even <20), and which are collected in only one device. We recommend not to use such a characterization method because it is highly inaccurate and unreliable (i.e., it cannot reliably demonstrate that the device effectively switches in every cycle and it ignores cycle-to-cycle and device-to-device variability). This has created a blurry vision of the real performance of RS devices and in many cases has exaggerated their potential. This article proposes and describes a method for the correct characterization of switching endurance in RS devices; this method aims to construct endurance plots showing one data point per cycle and resistive state and combine data from multiple devices. Adopting this recommended method should result in more reliable literature in the field of RS technologies, which should accelerate their integration in commercial products
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