235 research outputs found
System-Level Modeling of Endothelial Permeability Pathway and High-throughput Data Analysis for Disease Biomarker Selection
Ph.DDOCTOR OF PHILOSOPH
Preparation and thermal analysis kinetics of the core–nanoshell composite materials doped with Sm
The core–nanoshell composite materials with magnetic fly-ash hollow cenosphere as core and nano SmFeO3 as shell were synthesized by high-energy ball milling method. The magnetic fly-ash hollow cenosphere, samarium nitrate, and iron nitrate were used as raw materials. The synthesis and growth kinetics of the composite materials were investigated using the thermogravimetry and differential thermal analysis (TG–DTA) at different heating rates. The results show that the precursor of the composite materials decomposes in three steps. The apparent activation energy of each stage was calculated using the Doyle–Ozawa and Kissinger methods. The reaction order, frequency factor, and rate equations were also determined. The activation energy of the nano crystallite growth is calculated to be 16.12 kJ mol−1 according to kinetics theory of nano crystallite growth. It can be inferred that the crystallite grows primarily by means of an interfacial reaction during the thermal treatment. The magnetic properties and microwave absorbing properties of samples were analyzed by the vibrating sample magnetometer analysis and vector network analyzer. The results indicated that the exchange coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating, which cause outstanding magnetic properties. In the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the composite absorbers can achieve −32 dB. The magnetic properties of the composite material are better than those of single phase. So it is consistent with requirements of the microwave absorbing material at the low-frequency absorption.National Natural Science Foundation (China) (No. 20976018)Liaoning Sheng (China) (Science Research Plan Project, Higher Education Department (No. L2013176))China. Ministry of Education (Key Laboratory of Industrial Ecology and Environmental Engineering, KLIEEE-12-03)China. Ministry of Education (National Project of China ‘‘Innovation and Entrepreneurship Training Program of Undergraduate students’’ (201310150002)
Simvastatin suppresses cerebral aneurysm in rats through suppression of release of pro-inflammatory cytokines
Purpose: To investigate the protective effect of simvastatin (SA) against onset of cerebral aneurysmmediated inflammatory cytokine release and subsequent inflammation and degradation of the extracellular matrix of smooth muscle cells.Methods: Cerebral aneurysm was induced in male Wistar rats using elastase injection, and aneurysm growth was monitored for one month following SA treatment. Inhibition of aneurysm growth was determined along with the expression levels of chemokines and pro-inflammatory cytokines, including TNF-α, IL-8, IL-1β, IL-17, IL-6, macrophage chemoattractant protein-1 (MCP-1), and matrix metalloproteinases 2 and 9, using enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR).Results: Aneurysm size decreased in rats treated with SA, relative to values obtained for control rats (p < 0.05). The corresponding expressions of inflammatory cytokines and chemokines were also reduced following pre-treatment with SA (p < 0.05). The results indicate a reduction in the aneurysm area in rats pre-treated with SA, when compared to the untreated animals (p < 0.05).Conclusion: SA treatment inhibits the progression of cerebral aneurysms via its protective effect against inflammation, indicating its potential for use in the prevention and treatment of cerebralaneurysms
Polarization description of successive ferroelectric switching in hafnia
Intertwined ionic conduction and ferroelectric (FE) switching in HfO2 lead to
extensive focuses. To describe its fundamental phenomena, we present a
free-energy model describing the potential of ferroelectrics with successive FE
switching paths, and extend the domain model of ionic conduction to
ferroelectric domains. Associate theoretical analyses and first-principles
calculations suggest a nesting-domain pattern with opposite piezoelectric loops
during the nucleation-and-growth process in displacive FE-HfO2. A collective
oxygen ion conduction mechanism is also proposed with a field-dependent ionic
conductivity following the Merz's law. We conclude that the ionic
conductibility is concomitant with the ferroelectricity in HfO2, and it may
provide a new venue for pursuing low temperature fast oxide-ion conductors and
artificial synapses.Comment: 26 page
A Novel Double Cluster and Principal Component Analysis-Based Optimization Method for the Orbit Design of Earth Observation Satellites
The weighted sum and genetic algorithm-based hybrid method (WSGA-based HM), which has been applied to multiobjective orbit optimizations, is negatively influenced by human factors through the artificial choice of the weight coefficients in weighted sum method and the slow convergence of GA. To address these two problems, a cluster and principal component analysis-based optimization method (CPC-based OM) is proposed, in which many candidate orbits are gradually randomly generated until the optimal orbit is obtained using a data mining method, that is, cluster analysis based on principal components. Then, the second cluster analysis of the orbital elements is introduced into CPC-based OM to improve the convergence, developing a novel double cluster and principal component analysis-based optimization method (DCPC-based OM). In DCPC-based OM, the cluster analysis based on principal components has the advantage of reducing the human influences, and the cluster analysis based on six orbital elements can reduce the search space to effectively accelerate convergence. The test results from a multiobjective numerical benchmark function and the orbit design results of an Earth observation satellite show that DCPC-based OM converges more efficiently than WSGA-based HM. And DCPC-based OM, to some degree, reduces the influence of human factors presented in WSGA-based HM
Serum vitamin D deficiency in children and adolescents is associated with type 1 diabetes mellitus
Background: To investigate the relationship 25-hydroxy vitamin D (25OHD) level among children and in children with type 1 diabetes mellitus (T1DM).
Methods: A case–control study was conducted to compare the serum 25OHD levels between cases and controls. This study recruited 296 T1DM children (106 newly diagnosed T1DM patients and 190 established T1DM patients), and 295 age- and gender-matched healthy subjects as controls.
Results: The mean serum 25OHD in T1DM children was 48.69 ± 15.26 nmol/L and in the controls was 57.93 ± 19.03 nmol/L. The mean serum 25OHD in T1DM children was lower than that of controls (P 0.05).
Conclusion: Vitamin D deficiency is common in T1DM children, and it should be worthy of attention on the lack of vitamin D in established T1DM children
Anti-atherosclerosis mechanisms associated with regulation of non-coding RNAs by active monomers of traditional Chinese medicine
Atherosclerosis is the leading cause of numerous cardiovascular diseases with a high mortality rate. Non-coding RNAs (ncRNAs), RNA molecules that do not encode proteins in human genome transcripts, are known to play crucial roles in various physiological and pathological processes. Recently, researches on the regulation of atherosclerosis by ncRNAs, mainly including microRNAs, long non-coding RNAs, and circular RNAs, have gradually become a hot topic. Traditional Chinese medicine has been proved to be effective in treating cardiovascular diseases in China for a long time, and its active monomers have been found to target a variety of atherosclerosis-related ncRNAs. These active monomers of traditional Chinese medicine hold great potential as drugs for the treatment of atherosclerosis. Here, we summarized current advancement of the molecular pathways by which ncRNAs regulate atherosclerosis and mainly highlighted the mechanisms of traditional Chinese medicine monomers in regulating atherosclerosis through targeting ncRNAs
De novo transcriptome analysis of Medicago falcata reveals novel insights about the mechanisms underlying abiotic stress-responsive pathway
BACKGROUND: The entire world is facing a deteriorating environment. Understanding the mechanisms underlying plant responses to external abiotic stresses is important for breeding stress-tolerant crops and herbages. Phytohormones play critical regulatory roles in plants in the response to external and internal cues to regulate growth and development. Medicago falcata is one of the stress-tolerant candidate leguminous species and is able to fix atmospheric nitrogen. This ability allows leguminous plants to grow in nitrogen deficient soils. METHODS: We performed Illumina sequencing of cDNA prepared from abiotic stress treated M. falcata. Sequencedreads were assembled to provide a transcriptome resource. Transcripts were annotated using BLASTsearches against the NCBI non-redundant database and gene ontology definitions were assigned. Acomparison among the three abiotic stress treated samples was carried out. The expression of transcriptswas confirmed with qRT-PCR. RESULTS: We present an abiotic stress-responsive M. falcata transcriptome using next-generation sequencing data from samples grown under standard, dehydration, high salinity, and cold conditions. We combined reads from all samples and de novo assembled 98,515 transcripts to build the M. falcata gene index. A comprehensive analysis of the transcriptome revealed abiotic stress-responsive mechanisms underlying the metabolism and core signalling components of major phytohormones. We identified nod factor signalling pathways during early symbiotic nodulation that are modified by abiotic stresses. Additionally, a global comparison of homology between the M. falcata and M. truncatula transcriptomes, along with five other leguminous species, revealed a high level of global sequence conservation within the family. CONCLUSIONS: M. falcata is shown to be a model candidate for studying abiotic stress-responsive mechanisms in legumes. This global gene expression analysis provides new insights into the biochemical and molecular mechanisms involved in the acclimation to abiotic stresses. Our data provides many gene candidates that might be used for herbage and crop breeding. Additionally, FalcataBase (http://bioinformatics.cau.edu.cn/falcata/) was built for storing these data. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-2019-x) contains supplementary material, which is available to authorized users
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