231 research outputs found
Effect of Ceramic Properties and Depth-of-penetration Test Parameters on the Ballistic Performance of Armour CeramicsÂ
Through an analysis on the relationship among ceramic properties, the depth of penetration (DOP) test parameters and the ballistic performance of armour ceramics based on literatures, the effects of ceramic type, tile thickness and projectile velocity on the ballistic performance of different kinds of ceramics were investigated systematically. The results show that the ballistic performance of different armour ceramics mainly depends on its density, and by using thin ceramic tiles or under high velocity impact, the ceramic composite armour could not provide effective ballistic protection. Furthermore, the differences in the ballistic performance of armour ceramic are found due to the different ballistic performance criteria and DOP test conditions. Additionally, the slope of the depth of penetration (not include tile thickness) (Pa) versus tile thickness has negative correlation with flexural strength of ceramics, indicating the flexural strength can be one of the criteria to evaluate the performance of armour ceramics
Uncertainty in Future High Flows in Qiantang River Basin, China
AbstractUncertainties in high flows originating from greenhouse gas emissions scenarios, hydrological model structures, and their parameters for the Jinhua River basin, China, were assessed. The baseline (1961–90) and future (2011–40) climates for A1B, A2, and B2 scenarios were downscaled from the general circulation model (GCM) using the Providing Regional Climates for Impacts Studies (PRECIS) regional climate model with a spatial resolution of 50 km × 50 km. Bias-correction methods were applied to the PRECIS-derived temperature and precipitation. The bias-corrected precipitation and temperature were used as inputs for three hydrological models [modèle du Génie Rural à 4 paramètres Journalier (GR4J), Hydrologiska Byråns Vattenbalansavdelning (HBV), and Xinanjiang] to simulate high flows. The parameter uncertainty was considered and quantified in the hydrological model calibration by means of the generalized likelihood uncertainty estimation (GLUE) method for each hydrological model for the three emissions scenarios. It was found that, compared with the high flows in the baseline period, the high flows in the future tended to decrease under scenarios A1B, A2, and B2. The largest uncertainty was observed in HBV, and GR4J had the smallest uncertainty. It was found that the major source of uncertainty in this study was from parameters, followed by the uncertainties from the hydrological model structure, and the emissions scenarios have the smallest uncertainty contribution to high flows in this study.</jats:p
Diabetes Cognitive Impairments and the Effect of Traditional Chinese Herbs
The problem of cognitive impairment resulting from diabetes is gaining more acceptance and attention. Both type 1 and type 2 diabetes mellitus have been proved to be associated with reduced performance on numerous domains of cognitive function. Although the exact mechanisms of cognitive impairments in diabetes have not been completely understood, hyperglycemia and insulin resistance seem to play significant roles. And other possible risk factors such as hypoglycemia, insulin deficiency, vascular risk factors, hyperactive HPA axis, depression, and altered neurotransmitters will also be examined. In the meanwhile, this review analyzed the role of the active ingredient of Chinese herbal medicine in the treatment of diabetes cognitive impairments
A Semi-Analytical Models to Investigate Performance of Herringbone Wells
Abstract: For herringbone wells with antisymmetrical and curved laterals, the effects of lateral symmetry and camber on production of herringbone wells are analyzed by semi-analytical model. The effects of laterals with different angles, different number and different spans on production of herringbone wells are analyzed on this base. The results indicate that the contribution of mainbore of production is smaller than symmetrical herringbone well whereas the contribution of laterals of antisymmetrical herringbone well is bigger. The total production of antisymmetrical herringbone well is bigger than that of symmetrical herringbone well. The curved laterals will cause less production comparing with deviated laterals. The bigger the lateral angle is the higher is production of herringbone wells. The contribution of 1/3 lateral end accounts for about 50% of the total lateral contribution. While total length of laterals is the same, the production of well with two laterals on different sides of mainbore is the highest. Besides, laterals should be put as near as possible to the middle mainbore and there is an optimum span existed
Mitochondria DNA mutations cause sex-dependent development of hypertension and alterations in cardiovascular function
Aging is associated with conduit artery stiffening that is a risk factor for and can precede hypertension and ventricular dysfunction. Increases in mitochondria DNA (mtDNA) frequency have been correlated with aging. Mice with a mutation in the encoding domain (D257A) of a proof-reading deficient version of mtDNA polymerase-γ (POLG) have musculoskeletal features of premature aging and a shortened lifespan. However, few studies using these mice have investigated the effects of mtDNA mutations on cardiovascular function. We hypothesized that the proof-reading deficient mtDNA POLG leads to arterial stiffening, hypertension, and ventricular hypertrophy. Ten to twelve month-old D257A mice (n=13) and age- and sex-matched wild-type controls (n=13) were catheterized for hemodynamic and ventricular function measurements. Left common carotid arteries (LCCA) were harvested for mechanical tests followed by histology. Male D257A mice had pulmonary and systemic hypertension, arterial stiffening, larger LCCA diameter (701±45 vs. 597±60 μm), shorter LCCA axial length (8.96±0.56 vs. 10.10±0.80 mm), and reduced hematocrit (29.1±6.1 vs. 41.3±8.1; all p<0.05). Male and female D257A mice had biventricular hypertrophy (p<0.05). Female D257A mice did not have significant increases in pressure or arterial stiffening, suggesting that the mechanisms of hypertension or arterial stiffening from mtDNA mutations differ based on sex. Our results lend insight into the mechanisms of age-related cardiovascular disease and may point to novel treatment strategies to address cardiovascular mortality in the elderly
Bioinformatics analyses of gene expression profile to identify pathogenic mechanisms for COVID-19 infection and cutaneous lupus erythematosus
ObjectiveThe global mortality rates have surged due to the ongoing coronavirus disease 2019 (COVID-19), leading to a worldwide catastrophe. Increasing incidents of patients suffering from cutaneous lupus erythematosus (CLE) exacerbations after either contracting COVID-19 or getting immunized against it, have been observed in recent research. However, the precise intricacies that prompt this unexpected complication are yet to be fully elucidated. This investigation seeks to probe into the molecular events inciting this adverse outcome.MethodGene expression patterns from the Gene Expression Omnibus (GEO) database, specifically GSE171110 and GSE109248, were extracted. We then discovered common differentially expressed genes (DEGs) in both COVID-19 and CLE. This led to the creation of functional annotations, formation of a protein-protein interaction (PPI) network, and identification of key genes. Furthermore, regulatory networks relating to these shared DEGs and significant genes were constructed.ResultWe identified 214 overlapping DEGs in both COVID-19 and CLE datasets. The following functional enrichment analysis of these DEGs highlighted a significant enrichment in pathways related to virus response and infectious disease in both conditions. Next, a PPI network was constructed using bioinformatics tools, resulting in the identification of 5 hub genes. Finally, essential regulatory networks including transcription factor-gene and miRNA-gene interactions were determined.ConclusionOur findings demonstrate shared pathogenesis between COVID-19 and CLE, offering potential insights for future mechanistic investigations. And the identification of common pathways and key genes in these conditions may provide novel avenues for research
EO-1 Data Quality and Sensor Stability with Changing Orbital Precession at the End of a 16 Year Mission
The Earth Observing One (EO-1) satellite has completed 16 years of Earth observations in early 2017. What started as a technology mission to test various new advancements turned into a science and application mission that extended many years beyond the satellites planned life expectancy. EO-1s primary instruments are spectral imagers: Hyperion, the only civilian full spectrum spectrometer (430-2400 nm) in orbit; and the Advanced Land Imager (ALI), the prototype for Landsat-8s pushbroom imaging technology. Both Hyperion and ALI instruments have continued to perform well, but in February 2011 the satellite ran out of the fuel necessary to maintain orbit, which initiated a change in precession rate that led to increasingly earlier equatorial crossing times during its last five years. The change from EO-1s original orbit, when it was formation flying with Landsat-7 at a 10:01am equatorial overpass time, to earlier overpass times results in image acquisitions with increasing solar zenith angles (SZAs). In this study, we take several approaches to characterize data quality as SZAs increased. Our results show that for both EO-1 sensors, atmospherically corrected reflectance products are within 5 to 10 of mean pre-drift products. No marked trend in decreasing quality in ALI or Hyperion is apparent through 2016, and these data remain a high quality resource through the end of the mission
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A Versatile Surface Bioengineering Strategy Based on Mussel-Inspired and Bioclickable Peptide Mimic
In this work, we present a versatile surface engineering strategy by the combination of mussel adhesive peptide mimicking and bioorthogonal click chemistry. The main idea reflected in this work derived from a novel mussel-inspired peptide mimic with a bioclickable azide group (i.e., DOPA4-azide). Similar to the adhesion mechanism of the mussel foot protein (i.e., covalent/noncovalent comediated surface adhesion), the bioinspired and bioclickable peptide mimic DOPA4-azide enables stable binding on a broad range of materials, such as metallic, inorganic, and organic polymer substrates. In addition to the material universality, the azide residues of DOPA4-azide are also capable of a specific conjugation of dibenzylcyclooctyne- (DBCO-) modified bioactive ligands through bioorthogonal click reaction in a second step. To demonstrate the applicability of this strategy for diversified biofunctionalization, we bioorthogonally conjugated several typical bioactive molecules with DBCO functionalization on different substrates to fabricate functional surfaces which fulfil essential requirements of biomedically used implants. For instance, antibiofouling, antibacterial, and antithrombogenic properties could be easily applied to the relevant biomaterial surfaces, by grafting antifouling polymer, antibacterial peptide, and NO-generating catalyst, respectively. Overall, the novel surface bioengineering strategy has shown broad applicability for both the types of substrate materials and the expected biofunctionalities. Conceivably, the “clean” molecular modification of bioorthogonal chemistry and the universality of mussel-inspired surface adhesion may synergically provide a versatile surface bioengineering strategy for a wide range of biomedical materials
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