2,133 research outputs found
Thermal Properties and Biodegradability Studies of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)
For investigating the relationship between thermal properties and biodegradability of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), several films of PHBV containing different polyhydroxyvalerate (HV) fractions were subjected to degradation in different conditions for up to 49 days. Differential scanning calorimetry (DSC), thermogravimetry (TG), specimen weight loss and scanning electron microscopy (SEM) were performed to characterize the thermal properties and enzymatic biodegradability of PHBV. The experimental results suggest that the degradation rates of PHBV films increase with decreasing crystallinity; the degradability of PHBV occurring from the surface is very significant under enzymatic hydrolysis; the crystallinity of PHBV decreased with the increase of HV fraction in PHBV; and no decrease in molecular weight was observed in the partially-degraded polymer.Ningbo Natural Science Foundation (Grant 2006A610043)Science and Technology Department of Zhejiang Provincial Government (Grant 2007R10020
Halo Occupation Distribution Modeling of Clustering of Luminous Red Galaxies
We perform Halo Occupation Distribution (HOD) modeling to interpret
small-scale and intermediate-scale clustering of 35,000 luminous early-type
galaxies and their cross-correlation with a reference imaging sample of normal
L* galaxies in the Sloan Digital Sky Survey. The modeling results show that
most of these luminous red galaxies (LRGs) are central galaxies residing in
massive halos of typical mass M ~ a few times 10^13 to 10^14 Msun/h, while a
few percent of them have to be satellites within halos in order to produce the
strong auto-correlations exhibited on smaller scales. The mean luminosity Lc of
central LRGs increases with the host halo mass, with a rough scaling relation
of Lc \propto M^0.5. The halo mass required to host on average one satellite
LRG above a luminosity threshold is found to be about 10 times higher than that
required to host a central LRG above the same threshold. We find that in
massive halos the distribution of L* galaxies roughly follows that of the dark
matter and their mean occupation number scales with halo mass as M^1.5. The HOD
modeling results also allows for an intuitive understanding of the
scale-dependent luminosity dependence of the cross-correlation between LRGs and
L_* galaxies. Constraints on the LRG HOD provide tests to models of formation
and evolution of massive galaxies, and they are also useful for cosmological
parameter investigations. In one of the appendices, we provide LRG HOD
parameters with dependence on cosmology inferred from modeling the two-point
auto-correlation functions of LRGs.Comment: 21 pages, 10 figures, accepted for publication in Ap
Down-expression of inducible nitric oxide synthase (iNOS) and endothelial (Enos) proteins and mRNA iNOS in bronchiectasis in vivo
published_or_final_versio
The Taiwan ECDFS Near-Infrared Survey: Very Bright End of the Luminosity Function at z>7
The primary goal of the Taiwan ECDFS Near-Infrared Survey (TENIS) is to find
well screened galaxy candidates at z>7 (z' dropout) in the Extended Chandra
Deep Field-South (ECDFS). To this end, TENIS provides relatively deep J and Ks
data (~25.3 ABmag, 5-sigma) for an area of 0.5*0.5 degree. Leveraged with
existing data at mid-infrared to optical wavelengths, this allows us to screen
for the most luminous high-z objects, which are rare and thus require a survey
over a large field to be found. We introduce new color selection criteria to
select a z>7 sample with minimal contaminations from low-z galaxies and
Galactic cool stars; to reduce confusion in the relatively low angular
resolution IRAC images, we introduce a novel deconvolution method to measure
the IRAC fluxes of individual sources. Illustrating perhaps the effectiveness
at which we screen out interlopers, we find only one z>7 candidate, TENIS-ZD1.
The candidate has a weighted z_phot of 7.8, and its colors and luminosity
indicate a young (45M years old) starburst galaxy with a stellar mass of
3.2*10^10 M_sun. The result matches with the observational luminosity function
analysis and the semi-analytic simulation result based on the Millennium
Simulations, which may over predict the volume density for high-z massive
galaxies. The existence of TENIS-ZD1, if confirmed spectroscopically to be at
z>7, therefore poses a challenge to current theoretical models for how so much
mass can accumulate in a galaxy at such a high redshift.Comment: 14 pages, 11 figures, ApJ accepte
Perioperative challenges in managing a patient with COVID-19 undergoing debridement for massive scalp myiasis
A young man presented to our centre needing an urgent debridement of his postcraniotomy wound due to massive myiasis during the COVID-19 pandemic in October 2020. Prior to the surgery, his nasopharyngeal swab real-time PCR test result was unknown. One day later, it returned as SARS-CoV-2 positive. All healthcare workers who were involved in the patient management avoided cross infection as they wore appropriate personal protective equipment. This article depicts the importance of adequate preparations when handling potentially infectious patients and the perioperative issues associated with it
Carbon, Metals, and Grain Size Correlate with Bacterial Community Structure in Sediments of a High Arsenic Aquifer
Bacterial communities can exert significant influence on the biogeochemical cycling of arsenic (As). This has globally important implications since As in drinking water affects the health of over 100 million people worldwide, including in the Ganges–Brahmaputra Delta region of Bangladesh where geogenic arsenic in groundwater can reach concentrations of more than 10 times the World Health Organization’s limit. Thus, the goal of this research was to investigate patterns in bacterial community composition across gradients in sediment texture and chemistry in an aquifer with elevated groundwater As concentrations in Araihazar, Bangladesh. We characterized the bacterial community by pyrosequencing 16S rRNA genes from aquifer sediment samples collected at three locations along a groundwater flow path at a range of depths between 1.5 and 15 m. We identified significant differences in bacterial community composition between locations in the aquifer. In addition, we found that bacterial community structure was significantly related to sediment grain size, and sediment carbon (C), manganese (Mn), and iron (Fe) concentrations. Deltaproteobacteria and Chloroflexi were found in higher proportions in silty sediments with higher concentrations of C, Fe, and Mn. By contrast, Alphaproteobacteria and Betaproteobacteria were in higher proportions in sandy sediments with lower concentrations of C and metals. Based on the phylogenetic affiliations of these taxa, these results may indicate a shift to more Fe-, Mn-, and humic substance-reducers in the high C and metal sediments. It is well-documented that C, Mn, and Fe may influence the mobility of groundwater arsenic, and it is intriguing that these constituents may also structure the bacterial community
A Smooth-Turn Mobility Model for Airborne Networks
In this article, I introduce a novel airborne network mobility model, called the Smooth Turn Mobility Model, that captures the correlation of acceleration for airborne vehicles across time and spatial coordinates. Effective routing in airborne networks (ANs) relies on suitable mobility models that capture the random movement pattern of airborne vehicles. As airborne vehicles cannot make sharp turns as easily as ground vehicles do, the widely used mobility models for Mobile Ad Hoc Networks such as Random Waypoint and Random Direction models fail. Our model is realistic in capturing the tendency of airborne vehicles toward making straight trajectory and smooth turns with large radius, and whereas is simple enough for tractable connectivity analysis and routing design
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