332 research outputs found
Mechanistic representation of soil nitrogen emissions in the Community Multiscale Air Quality (CMAQ) model v 5.1
Soils are important sources of emissions of nitrogen-containing (N-containing) gases
such as nitric oxide (NO), nitrous acid (HONO), nitrous oxide (N2O),
and ammonia (NH3). However, most contemporary air quality models lack a
mechanistic representation of the biogeochemical processes that form these
gases. They typically use heavily parameterized equations to simulate
emissions of NO independently from NH3 and do not quantify emissions
of HONO or N2O. This study introduces a mechanistic, process-oriented
representation of soil emissions of N species (NO, HONO, N2O, and
NH3) that we have recently implemented in the Community Multiscale Air
Quality (CMAQ) model. The mechanistic scheme accounts for biogeochemical
processes for soil N transformations such as mineralization, volatilization,
nitrification, and denitrification. The rates of these processes are
influenced by soil parameters, meteorology, land use, and mineral N
availability. We account for spatial heterogeneity in soil conditions and
biome types by using a global dataset for soil carbon (C) and N across
terrestrial ecosystems to estimate daily mineral N availability in
nonagricultural soils, which was not accounted for in earlier parameterizations
for soil NO. Our mechanistic scheme also uses daily year-specific fertilizer
use estimates from the Environmental Policy Integrated Climate (EPIC v0509)
agricultural model. A soil map with sub-grid biome definitions was used to
represent conditions over the continental United States. CMAQ modeling for
May and July 2011 shows improvement in model performance in simulated
NO2 columns compared to Ozone Monitoring Instrument (OMI) satellite
retrievals for regions where soils are the dominant source of NO emissions.
We also assess how the new scheme affects model performance for NOx
(NO+NO2), fine nitrate (NO3) particulate matter, and ozone
observed by various ground-based monitoring networks. Soil NO emissions in
the new mechanistic scheme tend to fall between the magnitudes of the
previous parametric schemes and display much more spatial heterogeneity. The
new mechanistic scheme also accounts for soil HONO, which had been ignored
by parametric schemes.</p
Assessment of medication prescription errors and their contributory factors in major cities of Punjab Province, Pakistan: A cross-sectional survey
Purpose: To evaluate the prescription errors and their contributory factors in Punjab, Pakistan.Methods: An observational, cross-sectional study was conducted in 12 major cities of Punjab, Pakistan. A total of 1,184 prescriptions were collected from patients using a convenient sampling method from homes, pharmacies, clinics, and hospitals. The data were presented in frequency and percentage using descriptive statistics. To determine the association between the variables assessed, Chi-square (X2) test was used.Results: A total of 1,184 prescriptions were analyzed; 432 of them (36.5 %) were from prescribers who are graduate degree holders, and 752 (63.5 %) from prescribers who are post-graduate degree holders. The most commonly missing parameters in the prescriptions were the age of the patients (835 representing 29.4 %), signatures of the prescribers (755 representing 26.5 %), and prefix (622 representing 21.9 %). The number of prescription errors was significantly correlated to prescriber qualification (p = 0.001). The prescription errors were more common in age groups of prescribers: 21 - 30 years (654 representing 23.0 %), and 31 - 40 years (1,012 representing 35.6 %) (p = 0.001). The higher number of prescription errors by post-graduate prescribers working in teaching hospitals can be attributed to the higher patient load and lack of continuing medical education programs for the prescribers.Conclusion: The government should take necessary measures for the implementation of electronic prescribing systems, and devise mechanisms for the uniform distribution of patient load amongst the prescribers working in different hospitals.
Keywords: Prescription error, Prescribers, Patient load, Continuing medical education, Electronic prescribin
Performance Enhancement of a Graphene-Zinc Phosphide Solar Cell Using the Electric Field-Effect
The optical transparency and high electron mobility of graphene make it an attractive material for photovoltaics. We present a field-effect solar cell using graphene to form a tunable junction barrier with an Earth-abundant and low cost zinc phosphide (Zn_3P_2) thin-film light absorber. Adding a semitransparent top electrostatic gate allows for tuning of the graphene Fermi level and hence the energy barrier at the graphene-Zn_3P_2 junction, going from an ohmic contact at negative gate voltages to a rectifying barrier at positive gate voltages. We perform current and capacitance measurements at different gate voltages in order to demonstrate the control of the energy barrier and depletion width in the zinc phosphide. Our photovoltaic measurements show that the efficiency conversion is increased 2-fold when we increase the gate voltage and the junction barrier to maximize the photovoltaic response. At an optimal gate voltage of +2 V, we obtain an open-circuit voltage of V_(oc) = 0.53 V and an efficiency of 1.9% under AM 1.5 1-sun solar illumination. This work demonstrates that the field effect can be used to modulate and optimize the response of photovoltaic devices incorporating grapheme
Quantitative Proteomics Reveals GIMAP Family Proteins 1 and 4 to Be Differentially Regulated during Human T Helper Cell Differentiation
T helper (Th) cells differentiate into functionally distinct effector cell subsets of which Th1 and Th2 cells are best characterized. Besides T cell receptor signaling, IL-12-induced STAT4 and T-bet- and IL-4-induced STAT6 and GATA3 signaling pathways are the major players regulating the Th1 and Th2 differentiation process, respectively. However, there are likely to be other yet unknown factors or pathways involved. In this study we used quantitative proteomics exploiting cleavable ICAT labeling and LC-MS/MS to identify IL-4-regulated proteins from the microsomal fractions of CD4(+) cells extracted from umbilical cord blood. We were able to identify 557 proteins of which 304 were also quantified. This study resulted in the identification of the down-regulation of small GTPases GIMAP1 and GIMAP4 by IL-4 during Th2 differentiation. We also showed that both GIMAP1 and GIMAP4 genes are up-regulated by IL-12 and other Th1 differentiation-inducing cytokines in cells induced to differentiate toward Th1 lineage and down-regulated by IL-4 in cells induced to Th2. Our results indicate that the GIMAP (GTPase of the immunity-associated protein) family of proteins is differentially regulated during Th cell differentiation. Molecular & Cellular Proteomics 8:32-44, 2009
Quantitative Proteomics Reveals the Dynamic Protein Landscape during Initiation of Human Th17 Cell Polarization
Th17 cells contribute to the pathogenesis of inflammatory and autoimmune diseases and cancer. To reveal the Th17 cell-specific proteomic signature regulating Th17 cell differentiation and function in humans, we used a label-free mass spectrometry-based approach. Furthermore, a comprehensive analysis of the proteome and transcriptome of cells during human Th17 differentiation revealed a high degree of overlap between the datasets. However, when compared with corresponding published mouse data, we found very limited overlap between the proteins differentially regulated in response to Th17 differentiation. Validations were made for a panel of selected proteins with known and unknown functions. Finally, using RNA interference, we showed that SATB1 negatively regulates human Th17 cell differentiation. Overall, the current study illustrates a comprehensive picture of the global protein landscape during early human Th17 cell differentiation. Poor overlap with mouse data underlines the importance of human studies for translational research
Functional analysis of Ectodysplasin-A mutations causing selective tooth agenesis.
Mutations of the Ectodysplasin-A (EDA) gene are generally associated with the syndrome hypohidrotic ectodermal dysplasia (MIM 305100), but they can also manifest as selective, non-syndromic tooth agenesis (MIM300606). We have performed an in vitro functional analysis of six selective tooth agenesis-causing EDA mutations (one novel and five known) that are located in the C-terminal tumor necrosis factor homology domain of the protein. Our study reveals that expression, receptor binding or signaling capability of the mutant EDA1 proteins is only impaired in contrast to syndrome-causing mutations, which we have previously shown to abolish EDA1 expression, receptor binding or signaling. Our results support a model in which the development of the human dentition, especially of anterior teeth, requires the highest level of EDA-receptor signaling, whereas other ectodermal appendages, including posterior teeth, have less stringent requirements and form normally in response to EDA mutations with reduced activity
The status of hepatitis C virus infection among people who inject drugs in the Middle East and North Africa.
BACKGROUND AND AIMS: People who inject drugs (PWID) are a key population at high risk of hepatitis C virus (HCV) infection. The aim of this study was to delineate the epidemiology of HCV in PWID in the Middle East and North Africa (MENA). METHODS: Syntheses of data were conducted on the standardized and systematically assembled databases of the MENA HCV Epidemiology Synthesis Project, 1989-2018. Random-effects meta-analyses and meta-regressions were performed. Meta-regression variables included country, study site, year of data collection and year of publication [to assess trends in HCV antibody prevalence over time], sample size and sampling methodology. Numbers of chronically infected PWID across MENA were estimated. The Shannon Diversity Index was calculated to assess genotype diversity. RESULTS: Based on 118 HCV antibody prevalence measures, the pooled mean prevalence in PWID for all MENA was 49.3% [95% confidence interval (CI) = 44.4-54.1%]. The country-specific pooled mean ranged from 21.7% (95% CI = 4.9-38.6%) in Tunisia to 94.2% (95% CI = 90.8-96.7%) in Libya. An estimated 221 704 PWID were chronically infected, with the largest numbers found in Iran at 68 526 and in Pakistan at 46 554. There was no statistically significant evidence for a decline in HCV antibody prevalence over time. Genotype diversity was moderate (Shannon Diversity Index of 1.01 out of 1.95; 52.1%). The pooled mean percentage for each HCV genotype was highest in genotype 3 (42.7%) and in genotype 1 (35.9%). CONCLUSION: Half of people who inject drugs in the Middle East and North Africa appear to have ever been infected with hepatitis C virus, but there are large variations in antibody prevalence among countries. In addition to > 200 000 chronically infected current people who inject drugs, there is an unknown number of people who no longer inject drugs who may have acquired hepatitis C virus during past injecting drug use. Harm reduction services must be expanded, and innovative strategies need to be employed to ensure accessibility to hepatitis C virus testing and treatment
Interleukin-32 Promotes Osteoclast Differentiation but Not Osteoclast Activation
Background: Interleukin-32 (IL-32) is a newly described cytokine produced after stimulation by IL-2 or IL-18 and IFN-γ. IL-32 has the typical properties of a pro-inflammatory mediator and although its role in rheumatoid arthritis has been recently reported its effect on the osteoclastogenesis process remains unclear. Methodology/principal findings: In the present study, we have shown that IL-32 was a potent modulator of osteoclastogenesis in vitro, whereby it promoted the differentiation of osteoclast precursors into TRAcP+ VNR+ multinucleated cells expressing specific osteoclast markers (up-regulation of NFATc1, OSCAR, Cathepsin K), but it was incapable of inducing the maturation of these multinucleated cells into bone-resorbing cells. The lack of bone resorption in IL-32-treated cultures could in part be explain by the lack of F-actin ring formation by the multinucleated cells generated. Moreover, when IL-32 was added to PBMC cultures maintained with soluble RANKL, although the number of newly generated osteoclast was increased, a significant decrease of the percentage of lacunar resorption was evident suggesting a possible inhibitory effect of this cytokine on osteoclast activation. To determine the mechanism by which IL-32 induces such response, we sought to determine the intracellular pathways activated and the release of soluble mediators in response to IL-32. Our results indicated that compared to RANKL, IL-32 induced a massive activation of ERK1/2 and Akt. Moreover, IL-32 was also capable of stimulating the release of IL-4 and IFN-γ, two known inhibitors of osteoclast formation and activation. Conclusions/significance: This is the first in vitro report on the complex role of IL-32 on osteoclast precursors. Further clarification on the exact role of IL-32 in vivo is required prior to the development of any potential therapeutic approach
Performance Enhancement of a Graphene-Zinc Phosphide Solar Cell Using the Electric Field-Effect
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