241 research outputs found
Illustrating a new global-scale approach to estimating potential reduction in fish species richness due to flow alteration
Changes in river discharge due to human activities and climate change would
affect the sustainability of freshwater ecosystems. To globally assess how
changes in river discharge will affect the future status of freshwater
ecosystems, global-scale hydrological simulations need to be connected with
a model to estimate the durability of freshwater ecosystems. However, the
development of this specific modelling combination for the global scale is
still in its infancy. In this study, two statistical methods are introduced
to link flow regimes to fish species richness (FSR): one is based on a
linear relationship between FSR and mean river discharge (hereafter, FSR-MAD
method), and the other is based on a multi-linear relationship between FSR
and ecologically relevant flow indices involving several other flow
characteristics and mean river discharge (FSR-FLVAR method). The FSR-MAD
method has been used previously in global simulation studies. The FSR-FLVAR
method is newly introduced here. These statistical methods for estimating
FSR were combined with a set of global river discharge simulations to
evaluate the potential impact of climate-change-induced flow alterations on
FSR changes. Generally, future reductions in FSR with the FSR-FLVAR method
are greater and much more scattered than with the FSR-MAD method. In arid
regions, both methods indicate reductions in FSR because mean discharge is
projected to decrease from past to future, although the magnitude of
reductions in FSR is different between the two methods. In contrast, in
heavy-snow regions a large reduction in FSR is shown by the FSR-FLVAR method
due to increases in the frequency of low and high flows. Although further
research is clearly needed to conclude which method is more appropriate,
this study demonstrates that the FSR-FLVAR method could produce considerably
different results when assessing the global role of flow alterations in
changing freshwater ecosystems
Synthesis, FT-IR, UV-VIS, DFT studies and SCXRD structure of 1-(tert-butyl) 3-ethyl-3-(hydroxy(thiophen-2-yl)methyl)piperidine-1,3-dicarboxylate
The crystal structure of 1-(tert-butyl) 3-ethyl 3-(hydroxy(thiophen-2-yl)methyl)piperidine-1,3-dicarboxylate (C18H25NO5S) I has been determined by Single Crystal X-ray Diffraction (SCXRD) techniques. It crystallizes in the orthorhombic space group Pca21 with unit cell parameters a = 19.4502(13)Å, b= 6.3571(4)Å, c= 15.2577(10) Å and number of molecules per unit cell, z = 4. The intensity data have been collected at room température (293 K) and the structure has been solved by direct methods. The full matrix least-squares refinement has converged the final R-value to 0.035 for 2251 observed reflections. The piperidine ring adopts a chair conformation. The structure is stabilized by two C–H…O (intermolecular interactions) and five C–H…O (intramolecular interactions). The structural and spectral studies of 1-(tert-butyl) 3-ethyl 3-(hydroxy(thiophen-2-yl)methyl)piperidine-1,3-dicarboxylate have been carried out by using both experimental and quantum chemical techniques
Synthesis, FT-IR, UV-VIS, DFT studies and SCXRD structure of 1-(tert-butyl) 3-ethyl-3-(hydroxy(thiophen-2-yl)methyl)piperidine-1,3-dicarboxylate
1043-1056The crystal structure of 1-(tert-butyl) 3-ethyl 3-(hydroxy(thiophen-2-yl)methyl)piperidine-1,3-dicarboxylate (C18H25NO5S) I has been determined by Single Crystal X-ray Diffraction (SCXRD) techniques. It crystallizes in the orthorhombic space group Pca21 with unit cell parameters a = 19.4502(13)Å, b= 6.3571(4)Å, c= 15.2577(10) Å and number of molecules per unit cell, z = 4. The intensity data have been collected at room température (293 K) and the structure has been solved by direct methods. The full matrix least-squares refinement has converged the final R-value to 0.035 for 2251 observed reflections. The piperidine ring adopts a chair conformation. The structure is stabilized by two C–H…O (intermolecular interactions) and five C–H…O (intramolecular interactions). The structural and spectral studies of 1-(tert-butyl) 3-ethyl 3-(hydroxy(thiophen-2-yl)methyl)piperidine-1,3-dicarboxylate have been carried out by using both experimental and quantum chemical techniques
Comparative Thermal Analysis of Different Cool Roof Materials for Minimizing Building Energy Consumption
The roof and walls in the urban areas contribute to major share in the absorption of solar radiations and also retard the outflow of the absorbed radiation from the building envelope, thereby increasing the global warming by inducing the heat island effect. The impact of using cool roof technologies on the thermal comfort of the office buildings has been estimated. Cool roofs reduce electricity consumption for maintaining the temperature of the air-conditioned buildings in the comfort level and also increase comfort in buildings merely not relying completely on cooling equipment. The cool roofs and cool pavements, however, can mitigate summer urban heat islands by improving indoor air quality and comfort. The thermal analysis of different materials has been carried out to analyze the impact of the rate of heat transfer on the building envelope and the results obtained indicate that different cool roof techniques are beneficial in maintaining the comfort level of the building which purely depends on the ambient temperature conditions
Multiple publications: The main reason for the retraction of papers in computer science
This paper intends to review the reasons for the retraction over the last decade. The paper particularly aims at reviewing these reasons with reference to computer science field to assist authors in comprehending the style of writing. To do that, a total of thirty-six retracted papers found on the Web of Science within Jan 2007 through July 2017 are explored. Given the retraction notices which are based on ten common reasons, this paper classifies the two main categories, namely random and nonrandom retraction. Retraction due to the duplication of publications scored the highest proportion of all other reasons reviewed
Comparative Genomic Analysis of Chitinase and Chitinase-Like Genes in the African Malaria Mosquito (Anopheles gambiae)
Chitinase is an important enzyme responsible for chitin metabolism in a wide range of organisms including bacteria, yeasts and other fungi, nematodes and arthropods. However, current knowledge on chitinolytic enzymes, especially their structures, functions and regulation is very limited. In this study we have identified 20 chitinase and chitinase-like genes in the African malaria mosquito, Anopheles gambiae, through genome-wide searching and transcript profiling. We assigned these genes into eight different chitinase groupings (groups I–VIII). Domain analysis of their predicted proteins showed that all contained at least one catalytic domain. However, only seven (AgCht4, AgCht5-1, AgCht6, AgCht7, AgCht8, AgCht10 and AgCht23) displayed one or more chitin-binding domains. Analyses of stage- and tissue-specific gene expression revealed that most of these genes were expressed in larval stages. However, AgCht8 was mainly expressed in the pupal and adult stages. AgCht2 and AgCht12 were specifically expressed in the foregut, whereas AgCht13 was only expressed in the midgut. The high diversity and complexity of An. gambiae chitinase and chitinase-like genes suggest their diverse functions during different developmental stages and in different tissues of the insect. A comparative genomic analysis of these genes along with those present in Drosophila melanogaster, Tribolium castaneum and several other insect species led to a uniform classification and nomenclature of these genes. Our investigation also provided important information for conducting future studies on the functions of chitinase and chitinase-like genes in this important malaria vector and other species of arthropods
A retrospective analysis of glycol and toxic alcohol ingestion: utility of anion and osmolal gaps
<p>Abstract</p> <p>Background</p> <p>Patients ingesting ethylene glycol, isopropanol, methanol, and propylene glycol ('toxic alcohols') often present with non-specific signs and symptoms. Definitive diagnosis of toxic alcohols has traditionally been by gas chromatography (GC), a technique not commonly performed on-site in hospital clinical laboratories. The objectives of this retrospective study were: 1) to assess the diagnostic accuracy of the osmolal gap in screening for toxic alcohol ingestion and 2) to determine the common reasons other than toxic alcohol ingestion for elevated osmolal gaps.</p> <p>Methods</p> <p>Electronic medical records from an academic tertiary care medical center were searched to identify all patients in the time period from January 1, 1996 to September 1, 2010 who had serum/plasma ethanol, glucose, sodium, blood urea nitrogen, and osmolality measured simultaneously, and also all patients who had GC analysis for toxic alcohols. Detailed chart review was performed on all patients with osmolal gap of 9 or greater.</p> <p>Results</p> <p>In the study period, 20,669 patients had determination of serum/plasma ethanol and osmolal gap upon presentation to the hospitals. There were 341 patients with an osmolal gap greater than 14 (including correction for estimated contribution of ethanol) on initial presentation to the medical center. Seventy-seven patients tested positive by GC for one or more toxic alcohols; all had elevated anion gap or osmolal gap or both. Other than toxic alcohols, the most common causes for an elevated osmolal gap were recent heavy ethanol consumption with suspected alcoholic ketoacidosis, renal failure, shock, and recent administration of mannitol. Only 9 patients with osmolal gap greater than 50 and no patients with osmolal gap greater than 100 were found to be negative for toxic alcohols.</p> <p>Conclusions</p> <p>Our study concurs with other investigations that show that osmolal gap can be a useful diagnostic test in conjunction with clinical history and physical examination.</p
Pre-Clinical Evaluation of a Novel Nanoemulsion-Based Hepatitis B Mucosal Vaccine
Hepatitis B virus infection remains an important global health concern despite the availability of safe and effective prophylactic vaccines. Limitations to these vaccines include requirement for refrigeration and three immunizations thereby restricting use in the developing world. A new nasal hepatitis B vaccine composed of recombinant hepatitis B surface antigen (HBsAg) in a novel nanoemulsion (NE) adjuvant (HBsAg-NE) could be effective with fewer administrations.Physical characterization indicated that HBsAg-NE consists of uniform lipid droplets (349+/-17 nm) associated with HBsAg through electrostatic and hydrophobic interactions. Immunogenicity of HBsAg-NE vaccine was evaluated in mice, rats and guinea pigs. Animals immunized intranasally developed robust and sustained systemic IgG, mucosal IgA and strong antigen-specific cellular immune responses. Serum IgG reached > or = 10(6) titers and was comparable to intramuscular vaccination with alum-adjuvanted vaccine (HBsAg-Alu). Normalization showed that HBsAg-NE vaccination correlates with a protective immunity equivalent or greater than 1000 IU/ml. Th1 polarized immune response was indicated by IFN-gamma and TNF-alpha cytokine production and elevated levels of IgG(2) subclass of HBsAg-specific antibodies. The vaccine retains full immunogenicity for a year at 4 degrees C, 6 months at 25 degrees C and 6 weeks at 40 degrees C. Comprehensive pre-clinical toxicology evaluation demonstrated that HBsAg-NE vaccine is safe and well tolerated in multiple animal models.Our results suggest that needle-free nasal immunization with HBsAg-NE could be a safe and effective hepatitis B vaccine, or provide an alternative booster administration for the parenteral hepatitis B vaccines. This vaccine induces a Th1 associated cellular immunity and also may provide therapeutic benefit to patients with chronic hepatitis B infection who lack cellular immune responses to adequately control viral replication. Long-term stability of this vaccine formulation at elevated temperatures suggests a direct advantage in the field, since potential excursions from cold chain maintenance could be tolerated without a loss in therapeutic efficacy
Global, regional, and national sex-specific burden and control of the HIV epidemic, 1990–2019, for 204 countries and territories: the Global Burden of Diseases Study 2019
Background: The sustainable development goals (SDGs) aim to end HIV/AIDS as a public health threat by 2030. Understanding the current state of the HIV epidemic and its change over time is essential to this effort. This study assesses the current sex-specific HIV burden in 204 countries and territories and measures progress in the control of the epidemic. Methods: To estimate age-specific and sex-specific trends in 48 of 204 countries, we extended the Estimation and Projection Package Age-Sex Model to also implement the spectrum paediatric model. We used this model in cases where age and sex specific HIV-seroprevalence surveys and antenatal care-clinic sentinel surveillance data were available. For the remaining 156 of 204 locations, we developed a cohort-incidence bias adjustment to derive incidence as a function of cause-of-death data from vital registration systems. The incidence was input to a custom Spectrum model. To assess progress, we measured the percentage change in incident cases and deaths between 2010 and 2019 (threshold >75% decline), the ratio of incident cases to number of people living with HIV (incidence-to-prevalence ratio threshold <0·03), and the ratio of incident cases to deaths (incidence-to-mortality ratio threshold <1·0). Findings: In 2019, there were 36·8 million (95% uncertainty interval [UI] 35·1–38·9) people living with HIV worldwide. There were 0·84 males (95% UI 0·78–0·91) per female living with HIV in 2019, 0·99 male infections (0·91–1·10) for every female infection, and 1·02 male deaths (0·95–1·10) per female death. Global progress in incident cases and deaths between 2010 and 2019 was driven by sub-Saharan Africa (with a 28·52% decrease in incident cases, 95% UI 19·58–35·43, and a 39·66% decrease in deaths, 36·49–42·36). Elsewhere, the incidence remained stable or increased, whereas deaths generally decreased. In 2019, the global incidence-to-prevalence ratio was 0·05 (95% UI 0·05–0·06) and the global incidence-to-mortality ratio was 1·94 (1·76–2·12). No regions met suggested thresholds for progress. Interpretation: Sub-Saharan Africa had both the highest HIV burden and the greatest progress between 1990 and 2019. The number of incident cases and deaths in males and females approached parity in 2019, although there remained more females with HIV than males with HIV. Globally, the HIV epidemic is far from the UNAIDS benchmarks on progress metrics. Funding: The Bill & Melinda Gates Foundation, the National Institute of Mental Health of the US National Institutes of Health (NIH), and the National Institute on Aging of the NIH
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