277 research outputs found
A Study of Differences in Binding of Hepatic Nuclear Proteins to the Upstream Region of Glucocorticoid Regulated Tyrosine Aminotransferase Gene in Lean and Obese Rats.
Glucocorticoids are required for the development of all forms of experimental obesity. Studies on Zucker fa/fa rats have revealed that the obese Zucker rat is hyper-responsive to the effects of glucocorticoids. This excessive response may result from an alteration in level or activity of a transcription factor in nuclei of obese fa/fa rat. Evidence from gel retardation assays using DNA fragments from the upstream region of glucocorticoid regulated tyrosine aminotransferase (TAT) gene and the nuclear extracts from obese and lean rats showed in this study that an increased amount of DNA fragment was shifted by nuclear extracts from obese rats in comparison to that from lean rats, suggesting that an alteration in levels or activity of a transcription factor or factors was present in the nuclei of obese rats. Three proteins which have approximate molecular weight of 55, 59 and 62 KDa were purified from the specific DNA-protein complex which showed a difference between lean and obese rats. These three proteins were able to reconstitute the specific DNA-protein complexes in gel retardation assays. Antibody against glucocorticoid receptor did not alter the gel retardation pattern, while anti-HNF3 (hepatic nuclear factor 3 antibody caused a super-shift of DNA-protein complex, suggesting that HNF3 was one of the three proteins which formed the DNA-protein complexes. Northern blot analysis showed no significant difference in mRNA levels of HNF3 gene between lean and obese rats, suggesting that the increased formation of DNA-protein complex in obese rat may not reflect an increased amount of protein but may result from an increased affinity of HNF3 or an increased level or affinity of the other two nuclear proteins in the nuclei of obese rats. Dephosphorylation of the nuclear proteins altered the gel retardation pattern, suggesting that phosphorylation regulated the specific DNA-protein complex formation. Although the glucocorticoid receptor was not a part of the DNA-protein complex, the formation of the specific DNA-protein complexes changes in response to the change of glucocorticoid status, suggesting that the transcription factors that are responsible for the specific DNA-protein complex formation may be modulated directly or indirectly by glucocorticoids
Fuzzy-model-based robust fault detection with stochastic mixed time-delays and successive packet dropouts
This is the Post-Print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 IEEEThis paper is concerned with the network-based robust fault detection problem for a class of uncertain discrete-time Takagi–Sugeno fuzzy systems with stochastic mixed time delays and successive packet dropouts. The mixed time delays comprise both the multiple discrete time delays and the infinite distributed delays. A sequence of stochastic variables is introduced to govern the random occurrences of the discrete time delays, distributed time delays, and successive packet dropouts, where all the stochastic variables are mutually independent but obey the Bernoulli distribution. The main purpose of this paper is to design a fuzzy fault detection filter such that the overall fault detection dynamics is exponentially stable in the mean square and, at the same time, the error between the residual signal and the fault signal is made as small as possible. Sufficient conditions are first established via intensive stochastic analysis for the existence of the desired fuzzy fault detection filters, and then, the corresponding solvability conditions for the desired filter gains are established. In addition, the optimal performance index for the addressed robust fuzzy fault detection problem is obtained by solving an auxiliary convex optimization problem. An illustrative example is provided to show the usefulness and effectiveness of the proposed design method.This work was supported in part by the National Natural Science Foundation of China under Grant 61028008, 60825303, 61004067,
National 973 Project under Grant 2009CB320600, the Key Laboratory of Integrated Automation for the Process Industry (Northeastern University), Ministry of Education, the Engineering and Physical
Sciences Research Council (EPSRC) of the U.K. under Grant GR/S27658/01, the Royal Society of the U.K., the University of Hong
Kong under Grant HKU/CRCG/200907176129 and the Alexander von Humboldt Foundation of Germany
Optimization of cyclosporin A production by Beauveria nivea in continuous fed-batch fermentation
To develop the effective control method for fed-batch culture of cyclosporin A production, we chose fructose, L-valine and (NH4)2HPO4 as feeding nutrients and compared their productivities in relation to different concentrations. The feeding rate of three kinds of feeding materials was controlled to maintain the suitable residual concentration. The fed-batch fermentation results indicated that the optimal concentrations of fructose, L-valine and (NH4)2HPO4 were about 20 g/L, 0.5 g/L and 0.6 g/L for cyclosporin A production, respectively. The cultivation of Beauveria nivea could produce cyclosporin A up to 6.2 g/L for 240 hrs through a continuous feeding-rate-controlled-batch process under the optimal feeding conditions
Robust H∞ filtering for markovian jump systems with randomly occurring nonlinearities and sensor saturation: The finite-horizon case
This article is posted with the permission of IEEE - Copyright @ 2011 IEEEThis paper addresses the robust H∞ filtering problem for a class of discrete time-varying Markovian jump systems with randomly occurring nonlinearities and sensor saturation. Two kinds of transition probability matrices for the Markovian process are considered, namely, the one with polytopic uncertainties and the one with partially unknown entries. The nonlinear disturbances are assumed to occur randomly according to stochastic variables satisfying the Bernoulli distributions. The main purpose of this paper is to design a robust filter, over a given finite-horizon, such that the H∞ disturbance attenuation level is guaranteed for the time-varying Markovian jump systems in the presence of both the randomly occurring nonlinearities and the sensor saturation. Sufficient conditions are established for the existence of the desired filter satisfying the H∞ performance constraint in terms of a set of recursive linear matrix inequalities. Simulation results demonstrate the effectiveness of the developed filter design scheme.This work was supported in part by the National Natural Science Foundation
of China under Grants 61028008, 60825303, and 61004067, National 973 Project under Grant 2009CB320600, the Key Laboratory of Integrated Automation for the Process Industry (Northeastern University) from the Ministry of Education of China, the Engineering and Physical Sciences Research Council (EPSRC) of the U.K., under Grant GR/S27658/01, the Royal Society of the
U.K., and the Alexander von Humboldt Foundation of Germany
Influence of soil physicochemical properties on biometrical and physical features of persian oak wood
This article investigates the relationships between soil characteristics (physical and chemical) and wood properties of Persian oak in three different elevation sites. For this purpose, 27 trees were randomly chosen and cut in Zagros forests in western Iran. The test samples were prepared at the stem (breast height) to examine physical and biometrical properties. For each elevation site, four soil samples were obtained at a 0-20 cm soil depth under the canopy of each tree to measure soil properties, including clay, silt soil, sand soil, electrical conductivity, pH, nitrogen, phosphorus, potassium, and organic matter content. Then, the relationship of soil and wood properties was determined by principal component analysis. Results specified that there are a positive correlation between wood density and volumetric swelling with clay and available potassium. Moreover, the results revealed a positive correlation between fiber length, cell wall thickness, and fiber diameter with electrical conductivity, sand percentage, and total nitrogen content, respectively
Development of Large-And-Small Volume-Switching Rotary Compressor for Residential Multi-Connected Air-Conditioner
Residential Multi-Connected Air-Conditioner(RMAC) are widely used in urban residential in China, but they have low energy efficiency problems in daily use. They are mainly due to the air-conditioning habits of Chinese residents in part space and part time , Which makes RMAC most of the time only 1-2 indoor units are turned on, and 60% of the operating time is at a low load rate of less than 30%. During low load operation, the compressor\u27s efficiency drops sharply, and there is also the problem of frequent start and stop when the minimum output is too large. In order to solve this problem, a large-and-small volume switching compressor suitable for RMAC is developed. The compressor can choose single-cylinder small-volume operation or twin-cylinder large-volume operation according to the change of system load. The new compressor technology for RMAC improves the energy efficiency by 124% under 10% load, and avoids the problem of frequent start-stops at low loads, making RMAC more energy efficient and more comfortable
Finding Complex Biological Relationships in Recent PubMed Articles Using Bio-LDA
The overwhelming amount of available scholarly literature in the life
sciences poses significant challenges to scientists wishing to keep up with
important developments related to their research, but also provides a useful
resource for the discovery of recent information concerning genes, diseases,
compounds and the interactions between them. In this paper, we describe an
algorithm called Bio-LDA that uses extracted biological terminology to
automatically identify latent topics, and provides a variety of measures to
uncover putative relations among topics and bio-terms. Relationships identified
using those approaches are combined with existing data in life science datasets
to provide additional insight. Three case studies demonstrate the utility of
the Bio-LDA model, including association predication, association search and
connectivity map generation. This combined approach offers new opportunities
for knowledge discovery in many areas of biology including target
identification, lead hopping and drug repurposing.Comment: 14 pages, 8 figures, 10 table
Chem2Bio2RDF: a semantic framework for linking and data mining chemogenomic and systems chemical biology data
<p>Abstract</p> <p>Background</p> <p>Recently there has been an explosion of new data sources about genes, proteins, genetic variations, chemical compounds, diseases and drugs. Integration of these data sources and the identification of patterns that go across them is of critical interest. Initiatives such as Bio2RDF and LODD have tackled the problem of linking biological data and drug data respectively using RDF. Thus far, the inclusion of chemogenomic and systems chemical biology information that crosses the domains of chemistry and biology has been very limited</p> <p>Results</p> <p>We have created a single repository called Chem2Bio2RDF by aggregating data from multiple chemogenomics repositories that is cross-linked into Bio2RDF and LODD. We have also created a linked-path generation tool to facilitate SPARQL query generation, and have created extended SPARQL functions to address specific chemical/biological search needs. We demonstrate the utility of Chem2Bio2RDF in investigating polypharmacology, identification of potential multiple pathway inhibitors, and the association of pathways with adverse drug reactions.</p> <p>Conclusions</p> <p>We have created a new semantic systems chemical biology resource, and have demonstrated its potential usefulness in specific examples of polypharmacology, multiple pathway inhibition and adverse drug reaction - pathway mapping. We have also demonstrated the usefulness of extending SPARQL with cheminformatics and bioinformatics functionality.</p
Possible Influence of δ-Aminolevulinic Acid Dehydratase Polymorphism and Susceptibility to Renal Toxicity of Lead: A Study of a Vietnamese Population
We examined six newly identified polymorphisms in the δ-aminolevulinic acid dehydratase (ALAD) single-nucleotide polymorphisms (SNPs) to determine if these SNPs could modify the relationship between blood lead (PbB) and some renal parameters. This is a cross-sectional study of 276 lead-exposed workers in Vietnam. All workers were measured for PbB, urinary retinol-binding protein (URBP), urinary α(1)-microglobulin (Uα1m), urinary β(2)-microglobulin (Uβ2m), urinary N-acetyl-β-d-glucosaminidase (NAG), urinary aminolevulinic acid (ALAU), serum α(1)-microglobulin (Sα1m), serum β(2)-microglobulin (Sβ2m), and urinary albumin (Ualb). The six SNPs were Msp and Rsa in exon 4, Rsa39488 in exon 5, HpyIV and HpyCH4 in intron 6, and Sau3A in intron 12. Analysis of covariance (ANCOVA) with interaction of PbB × SNPs were applied to examine modifying effect of the SNPs on the association of renal parameters and PbB, adjusting for potential confounders of age, gender, body mass index, and exposure duration. HpyCH4 was found to be associated with certain renal parameters. For HpyCH4 1-1, an increase of 1 μg/dL PbB caused an increase of 1.042 mg/g creatinine (Cr) Uα1m, 1.069 mg/g Cr Uβ2m, 1.038 mg/g Cr URBP, and 1.033 mg/g Cr Ualb, whereas in HpyCH4 1-2, an increase of 1 μg/dL PbB resulted in an increase of only 1.009 mg/g Cr Uα1m, 1.012 mg/g Cr Uβ2m, 1.009 mg/g Cr URBP, and 1.007 mg/g Cr Ualb. HpyCH4 SNP appeared to modify the lead toxicity to kidney with wild-type allele being more susceptible than variants. The mechanism for this effect is not clear. Further studies are needed to confirm this observation
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