Recent studies have indicated that the DNA replication machinery is coupled to silencing of mating-type loci in the budding yeast Saccharomyces cerevisiae, and a similar silencing mechanism...Full Text Available
In this study, we investigated on a systems level how complex protein interactions underlying cell polarity in yeast determine the dynamic association of proteins with the polar cortical domain (PCD)...Full Text Available
BackgroundHistone post-translational modifications are critical for gene expression and cell viability. A broad spectrum of histone lysine residues have been identified in yeast...Full Text Available
We study the growth of colonies of the yeast Pichia membranaefaciens on agarose film. The growth conditions are controlled in a setup where nutrients are supplied through an agarose film suspended over a solution of nutrients. As the thickness of the agarose film is varied, the morphology of the front of the colony changes. The growth of the front is modeled by coupling it to a diffusive field of inhibitory metabolites. Qualitative agreement with experiments suggests that such a coupling is responsible for the observed instability of the front.
The role of intermediate products of dioxygen reduction in cytotoxic effects ascribed to oxygen molecules was studied in vivo using various yeast mutants with changed response to oxygen stress. It has been documented that superoxide radical exerts its deleterious effects on yeastcells directly and the role of other oxygen species derived from it is hardly detectable. Yeast Saccharomyces cerevisiae, however, cannot be considered as a typical eukaryotic organism due to its inability of synthesizing polyunsaturated fatty acids (pufa). These fatty acids are known as main target molecules during oxidative stress and their peroxidation leads to cytotoxic effects. As fatty acid content could be easily manipulated in yeast, this organism was used to evaluate the contribution of pufa peroxidation process to the cytotoxic effects of oxygen. Results obtained show, that ...
A number of preparations of residual non-living brewery yeast were examined for their ability to remove lead from solution. Those preparations included washed and un-washed intact yeast and washed and un-washed homogenates of the yeastcells. Using biosorption isotherm analysis it was found that the washed and un-washed preparations of intact, non-living yeast exhibited maximum biosorption capacities for lead of 127 and 99 mg/g dry weight biomass, respectively. The washed and un-washed cell homogenates exhibited maximum biosorption capacities of 38 and 139 mg lead/g dry weight biomass, respectively. Since it had previously been shown that these preparations of biomass were capable of removing uranium from solution by combined biosorption and precipitation processes, it was decided to examine removal of lead from solution using a form of equilibrium dialysis in ...
The opportunistic pathogenic yeast Candida albicans exhibits growth phase-dependent changes in cell surface hydrophobicity, which has been correlated with adhesion to host tissues....Full Text Available
The yeast phosphatidylinositol transfer protein (Sec14p) is required for biogenesis of Golgi-derived transport vesicles and cell viability, and this essential Sec14p requirement is abrogated by inactivation...Full Text Available
Cultured fish and human cells have been used as bioassay systems for the evaluation of the toxicity of aquatic pollutants. Numerous assays using bacteria and yeast have also been used for such purposes. The authors report the toxicity of aquatic pollutants (Cd, Hg, and Ni), using cell culture systems and the yeast Saccharomyces cervisiae test. Cd, Hg, and Ni were chosen as model compounds of pollutants because the related toxicity is now fairly well established.
Over the decades, basic research in life sciences has profited greatly from the study of the small unicellular fungal species Saccharomyces cerevisiae. This yeast turned out to be key for the identification and understanding of molecular mechanisms that underlay the basic functions of all eukaryotic cells. These include, but are not limited to, the regulatory mechanisms behind cellular reproduction (cell cycle control), cellular morphogenesis (cell polarity, cytoskeleton and membrane trafficking) and the management of cellular information (chromosome biology, transcription and translation). Rapid access to genomic information of many yeast species, combined with bioinformatics analyses, provide information on the evolutionary history of yeasts and the molecular ancestry of their constituen...
The mini-chromosome maintenance proteins Mcm2–7 are essential for DNA replication. They are loaded onto replication origins during G1 phase of the cell cycle to form a pre-replication complex...Full Text Available
Eukaryotic cells can massively transport their own cytoplasmic contents into a lytic compartment, the vacuole/lysosome, for recycling through a conserved system called autophagy. The key process in...Full Text Available
BackgroundThe expression of human virus surface proteins, as well as other mammalian glycoproteins, is much more efficient in cells of higher eukaryotes rather than yeasts. The limitations...Full Text Available
The number of nuclear pore complexes (NPCs) in individual nuclei of the yeast Saccharomyces cerevisiae was determined by computer-aided reconstruction of entire nuclei from electron...Full Text Available
To gain insight into the process of mitochondrial transmission in yeast, we directly labeled mitochondrial proteins and mitochondrial DNA (mtDNA) and observed their fate after the fusion of two cells....Full Text Available
Cdc13 is a single stranded telomere binding protein that specifically localizes to the telomere ends of budding yeasts and is essential for cell viability. It caps the ends of chromosomes thus preventing...Full Text Available
Ethanol has excellent fuel properties, such as high octane, high heat of vaporization and low photochemical reactivity in the atmosphere. It is less volatile than gasoline and there is lower smog formation from evaporative emissions of pure ethanol compared to gasoline. As such, ethanol has emerged as an important alternative energy source that is sustainable, efficient, cost effective, convenient and safe. In 2006, global production of ethanol reached 13.5 billion gallons, up from 12.1 billion gallons in 2005. However, in light of the current debate of food versus fuel, the industry must shift to non-food feedstocks. This paper described an emerging technology to cost-effectively produce ethanol from sweet sorghum stalks, the most promising alternative feedstock to corn, via solid state fermentation (SSF). Experiments of advanced solid state fermentation (ASSF) for ethanol production from sweet sorghum by Saccharomyces cerevisiae were conducted in laboratory and pilot scales studies. ...
The principle aim of the program was to produce a novel, non-leaching antimicrobial surface for commercial development and future use in the liquid food packaging industry. Antimicrobial surfaces which exist presently have been produced to combat the growth of prokaryotic organisms and usually function as slow release systems. A system which could inhibit eukaryotic growth without contaminating the surrounding 'environment' with the inhibitor was considered of great commercial importance. The remit of this study was concerned with creating a surface which could control the growth of eukaryotic organisms found in fruit juice with particular interest in the yeast, Saccharomyces cerevisiae. Putative antimicrobial surfaces were created by the chemical modification of the test substrate polymers; nylon and ethylvinyl alcohol (EVOH). Surfaces were chemically modified by the covalent coupling of antimicrobial agents known to be ...
Lethal alleles of the Drosophila k43 gene result in small or missing imaginal discs, greatly reduced mitotic index, and fragmented and abnormally condensed chromosomes. A female-sterile...Full Text Available
The Sin3-histone deacetylase (HDAC) corepressor complex is conserved from yeast to humans. Mammals possess two highly related Sin3 proteins, mSin3A and mSin3B, which serve as scaffolds tethering HDAC...Full Text Available
The histone chaperone Asf1 and the chromatin remodeler SWI/SNF have been separately implicated in derepression of the DNA damage response (DDR) genes in yeastcells treated with genotoxins that cause...Full Text Available
A refined map for the linear arrangement of histones along DNA in nucleosomal core particles has been determined by DNA-protein crosslinking. On one strand of 145-bp core DNA, histones are aligned in...Full Text Available
Investigations into sexual differentiation and pheromone response in the fission yeast Schizosaccharomyces pombe are complicated by the need to first starve the cells of nitrogen. Most mating-related experiments are therefore performed on non-dividing cells. Here we overcome this problem by using two mutants that bypass the nutritional requirements and respond to the M-factor mating pheromone in rich medium. The first mutant lacks the cyr1 gene which encodes adenylate cyclase and these cells contain no measurable amounts of cAMP. When M-factor is added to a growing h+ cyr1- strain it causes a transient G1 arrest of cell division, transcription of mat1-Pm, and elongation of the cells to form shmoos. The second mutant contains the temperature-sensitive pat1-114 allele. At 30 degrees C this mutant was previously shown not only to bypass the nutritional signal but ...
For proper tissue morphogenesis, cell divisions and cell fate decisions must be tightly and coordinately regulated. One elegant way to accomplish this is to couple them with asymmetric cell divisions....Full Text Available
Abstract Microbial cells are routinely dried and ground before they are used in metal biosorption studies. In this work, a metal biosorbent was prepared by drying biomass of the yeast Rhodotorula glutinis in an oven at 70C for 24-h followed by grinding. Two forms of the prepared biosorbent particles, washed and unwashed, were examined for their ability to remove lead from solution. It was found that the unwashed biosorbent exhibited higher lead uptake than the washed biosorbent. Analysis of the supernatant of washed cells incubated in water and that of unwashed cells incubated in lead solution revealed the presence of protein, carbohydrates, organic acids and inorganic phosphate. Overall, the washed and unwashed cells leached, respectively, 14.5 and 13.4% of their initial dry weight (100-m...
The biodegradation of ring-/sup 14/C- and methyl-/sup 14/C-labeled paraquat by the soil yeast Lipomyces starkeyi was studied in vitro. It was found that the degradation of paraquat (acting as a sole source of culture nitrogen) resulted in the accumulation in the extracellular medium of radiolabeled acetic acid. The culture also evolved radiolabeled CO/sub 2/. The results suggest that the degradation of paraquat by L. starkeyi is associated with the integrity of the cell wall and that disruption or removal of the wall results in a complete loss of degradative capability. A mechanism for the degradation of paraquat by this organism is postulated.
The biodegradation of ring-"1"4C- and methyl-"1"4C-labeled paraquat by the soil yeast Lipomyces starkeyi was studied in vitro. It was found that the degradation of paraquat (acting as a sole source of culture nitrogen) resulted in the accumulation in the extracellular medium of radiolabeled acetic acid. The culture also evolved radiolabeled CO_2. The results suggest that the degradation of paraquat by L. starkeyi is associated with the integrity of the cell wall and that disruption or removal of the wall results in a complete loss of degradative capability. A mechanism for the degradation of paraquat by this organism is postulated.
Although genetic engineering techniques for baker's yeast might improve the yeast's fermentation characteristics, the lack of scientific data on the survival of such strains in natural environments...Full Text Available
A mesophilic yeast, Candida utilis, and a psychrophilic yeast, Leucosporidium stokesii, were subjected to freeze-thaw cycling over the range 25 to -60 C. Viability...Full Text Available
Ethidium bromide (EB) and ultraviolet light (UV) in combination are known to produce a synergistic induction of 'petite' mutants in yeast. Two other agents were combined with EB, 3-Carbethoxypsoralene (3 CPs) activated by 365 nm light or #gamma# rays. EB in combination with 3 CPs also resulted in an enhanced production of 'petite' mutants. After the photoaddition of 3 CPs in exponential phase cells, recovery of the 'petite' mutation during dark liquid holding was inhibited by the presence of EB producing an enhanced number of 'petite' mutants. The behavior of mitochondrial antibiotic resistance markers after individual and combined treatments with EB and 3 CPs indicates a random loss of markers after EB and a preferential loss of a certain region for the 3 CPs photoaddition. The combination of the two agents leads to an additivity of total drug marker losses rather than a synergistic loss. The combination of EB with #gamma# rays produced no ...
We report an analysis of four strains of baker's yeast (Saccharomyces cerevisiae) using biocavity laser spectroscopy. The four strains are grouped in two pairs (wild type and altered), in which one strain differs genetically at a single locus, affecting mitochondrial function. In one pair, the wild-type rho+ and a rho0 strain differ by complete removal of mitochondrial DNA (mtDNA). In the second pair, the wild-type rho+ and a rho- strain differ by knock-out of the nuclear gene encoding Cox4, an essential subunit of cytochrome c oxidase. The biocavity laser is used to measure the biophysical optic parameter Deltalambda, a laser wavelength shift relating to the optical density of cell or mitochondria that uniquely reflects its size and biomolecular composition. As such, Deltalambda is a powerful parameter that rapidly interrogates the biomolecular state of single cells and mitochondria. Wild-type ...
We investigate a method for gene delivery to vascular smooth muscle cells using ultrasound triggered delivery of plasmid DNA from electrostatically coupled cationic microbubbles. Microbubbles...Full Text Available
Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium...Full Text Available
We explored transcriptional responses of the fission yeast Schizosaccharomyces pombe to various environmental stresses. DNA microarrays were used to characterize changes in expression...Full Text Available
Budding yeasts are highly suitable for aging studies, because the number of bud scars (stage) proportionally correlates with age. Its maximum stages are known ...Full Text Available
Amphiphysin is a protein concentrated in neuronal synapses and peripherally associated with neurotransmitter vesicles. It is expressed in many neurons of the central and peripheral nervous systems, in the adrenal medulla, in the anterior and posterior pituitary, in cell lines of the endocrine pancreas, and in spermatocytes. Its subcellular localization and tissue distribution indicate a potential involvement in mechanisms of regulated exocytosis. A role in the dynamic organization of the membrane-associated cytoskeleton is suggested by structural homology to the products of two yeast genes, RVS161 and RVS167, whose mutation results in an abnormal actin distribution, disturbs budding morphology, and impairs cell entry into stationary phase. Limited stretches of sequence similarity, including an SH3 domain, are also shared with other actin-binding proteins. Amphiphysin is the dominant autoantigen in paraneoplastic Stiff-Man ...
Many aspects of cellular motility and mechanics are cyclic in nature such as the extension and retraction of lamellipodia or filopodia. Inherent to the cycles of extension and retraction that test the environment is the production of mechano-chemical signals that can alter long-term cell behavior, transcription patterns, and cell fate. We are just starting to define such cycles in several aspects of cell motility, including periodic contractions, integrin cycles of binding and release as well as the normal oscillations in motile activity. Cycles of local cell contraction and release are directly coupled to cycles of stressing and releasing extracellular contacts (matrix or cells) as well as cytoplasmic mechanotransducers. Stretching can alter external physical properties or sites exposed b...
All organisms, from bacteria and yeast to humans, respond to physical and chemical stressors by increasing the synthesis of a small group of cellular stress proteins.'' The authors have developed a simple in vitro system for quickly screening environmentally relevant stressors to detect stress-induced proteins that are good candidates for biomarkers. Polyacrylamide gel electrophoresis was used to detect stressor-induced, concentration-dependent changes in cellular stress protein levels in two fish cell culture systems, whereas simultaneous in vitro neutral red uptake cytotoxicity assays measured the stressors effect on cellular physiology. There was a direct concentration-dependent relationship between sublethal cytotoxic effects and the increases in stress protein levels. Increases of 50 to 200% were detected in stress proteins from desert topminnow, Poeciliopsis lucida, hepatoma-derived cell cultures ...
DFNA5 was first identified as a gene causing autosomal dominant hearing loss (HL). Different mutations have been found, all exerting a highly specific gain-of-function effect, in which skipping of exon 8 causes the HL. Later reports revealed the involvement of the gene in different types of cancer. Epigenetic silencing of DFNA5 in a large percentage of gastric, colorectal and breast tumors and p53-dependent transcriptional activity have been reported, concluding that DFNA5 acts as a tumor suppressor gene in different frequent types of cancer. Despite these data, the molecular function of DFNA5 has not been investigated properly. Previous transfection studies with mutant DFNA5 in yeast and in mammalian cells showed a toxic effect of the mutant protein, which was not seen after transfection ...
The gene encoding the human type I pituitary adenylate cyclase activating polypeptide receptor (ADCYAP1R1) was mapped to chromosome 7 by PCR analysis of genomic DNA from a human/rodent somatic cell hybrid mapping panel. This assignment was confirmed and the gene localized to chromosome band 7p14 by fluorescence in situ hybridization. A yeast artificial chromosome containing ADCYAP1R1 was identified in the CEPH {open_quotes}B{close_quotes} Mega-YAC library. This YAC includes two highly polymorphic dinucleotide repeat sequences that will facilitate genetic studies of the contribution of ADCYAP1R1 in disease states of the central nervous and neuroendocrine systems. 13 refs., 1 fig.
We determined the chromosomal localization and structure of the gene encoding human type II inosine 5{prime}-monophosphate dehydrogenase (IMPDH, EC 1.1.1.205), an enzyme associated with cellular proliferation, malignant transformation, and differentiation. Using polymerase chain reaction (PCR) primers specific for type II IMPDH, we screened a panel of human-Chinese hamster cell somatic hybrids and a separate deletion panel of chromosome 3 hybrids and localized the gene to 3p21.1{yields}p24.2. Two overlapping yeast artificial chromosome clones containing the full gene for type II IMPDH were isolated and a physical map of 117 kb of human genomic DNA in this region of chromosome 3 was constructed. The gene for type II IMPDH was localized and oriented on this map and found to span no more than 12.5 kb.
Scientists at JPL have developed chemical and biological techniques using microspheres filled with drugs, electron-opaque metals, or radioactive, fluorescent, magnetic or electrically charged materials to label specific groups of cells. Synthetic polymeric microspheres are coupled with specific antibodies to form reagents called immunomicrospheres, which can seek out and attach themselves to any specific group of cells. These cell-labeling techniques, therefore, open new avenues not only to the basic study of cells but also to the diagnosis and treatment of many diseases, including cancer.
The goal of the present work was to determine the impact of N3-methyladenine (3-mA), an important lesion generated by many environmental agents and anticancer drugs, on in vivo DNA replication and in vitro RNA transcription. Due to 3-mA chemical instability, the stable isostere 3-methyl-3-deazaadenine (3-m-c(3)A) was site specifically positioned into an oligodeoxynucleotide. The oligomer was, then incorporated into a vector system that is rapidly converted to ssDNA inside yeastcells and requires DNA replication opposite the lesion for plasmid clonal selection. For control purposes, an adenine or a stable apurinic/apyrimidinic (AP)-lesion was placed at the same site. The presence of each lesion in the oligonucleotide was confirmed by MALDI-TOF analysis. Plasmids were then transfected into yeastcells. While the AP-site dramatically reduced plasmid replication in all strains, the 3-m-c(3)A had a slight ...
Cdc7 kinase plays an essential role in firing of replication origins by phosphorylating components of the replication complexes. Cdc7 kinase has also been implicated in S phase checkpoint signaling downstream of the ATR and Chk1 kinases. Inactivation of Cdc7 in yeast results in arrest of cell growth with 1C DNA content after completion of the ongoing DNA replication. In contrast, conditional inactivation of Cdc7 in undifferentiated mouse embryonic stem (ES) cells leads to growth arrest with rapid cessation of DNA synthesis, suggesting requirement of Cdc7 functions for continuation of ongoing DNA synthesis. Furthermore, loss of Cdc7 function induces recombinational repair (nuclear Rad51 foci) and G2/M checkpoint responses (inhibition of Cdc2 kinase). Eventually, p53 becomes highly activated and the cells undergo massive p53-dependent apoptosis. Thus, defective origin activation in mammalian ...
Cytosine methylation in DNA is a major epigenetic signal, and plays a central role in propagating chromatin status during cell division. However the mechanistic links between DNA methylation...Full Text Available
G-protein-coupled receptor signalling has been suggested to be voltage dependent in a number of cell types; however, the limits of sensitivity of this potentially important phenomenon are unknown. Using...Full Text Available
The mechanism of cytokinesis has been difficult to define because of the short duration and the temporal-spatial dynamics involved in the formation, activation, force production, and disappearance of...Full Text Available
SUMMARYMotile dendritic filopodial processes are thought to be precursors of spine synapses, but how motility relates to cell-surface cues required for axon-dendrite recognition...Full Text Available
de Vito, Peter C. (Princeton University, Princeton, N.J.), and Jacques Dreyfuss. Metabolic regulation of adenosine triphosphate sulfurylase in yeast. J. Bacteriol. 88:1341–1348....Full Text Available
To define the import pathway for apoiso-1-cytochrome c in vivo, the coding region for bacterial chloramphenicol acetyltransferase (CAT) or yeast copper metallothionein (CuMT) was fused to the carboxy...Full Text Available
The electrokinetic patterns of four bacterial species (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, and Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae and Candida...Full Text Available
We have identified five acyl coenzyme A (CoA) oxidase isozymes (Aox1 through Aox5) in the n-alkane-assimilating yeast Yarrowia lipolytica, encoded by the POX1...Full Text Available
The ability of residual biomass from the thermotolerant ethanol-producing yeast strain Kluyveromyces marxianus IMB3 to function as a biosorbent for uranium has been examined. It was found that the biomass had an observed maximum biosorption capacity of 120 mg U/g dry weight of biomass. The calculated value for the biosorption maximum, obtained by fitting the data to the Langmuir model was found to be 130 mg U/g dry weight biomass. Maximum biosorption capacities were examined at a number of temperatures and both the observed and calculated values obtained for those capacities increased with increasing temperature. Decreasing the pH of the biosorbate solution resulted in a decrease in uptake capacity. When biosorption reactions were carried out using sea-water as the diluent it was found that the maximum biosorption capacity of the biomass increased significantly. Using transmission electron microscopy, uranium crystals were shown to be concentrated on the outer ...
The uncoupling protein (UCP) is a proton/anion transporter found in the inner mitochondrial membrane of brown adipocyte. Although UCP has nor been detected in mitochondria from any other tissue, it shares structural and catalytic properties with several other mitochondrial carrier proteins. Although UCP was discovered only recently it is one of the most extensively studied mitochondrial carrier proteins.More recently, the mouse, rat, and human genes encoding for UCP have been isolated and sequenced. The availability of these various tools has led to several significant observations. UCP gene expression is strongly controlled at the level of transcription by signals that are activated after the stimulation of brown adipocytes by norepinephrine. The comparison of UCP gene with the genes encoding the adenine nucleotide translocator revealed the existence of structural and evolutionary homologies. Moreover, in humans the UCP gene and one form of adenine nucleotide translocator gene are ...
BACKGROUND AND PURPOSE Controlling vascular tone involves K+ efflux through endothelial cell small- and intermediate-conductance calcium-activated potassium channels (KCa2.3 and KCa3.1, respectively). We investigated the expression of these channels in astrocytes and the possibility that, by a similar mechanism, they might contribute to neurovascular coupling. EXPERIMENTAL APPROACH Transgenic mice expressing enhanced green fluorescent protein (eGFP) in astrocytes were used to assess KCa2.3 and KCa3.1 expression by immunohistochemistry and RT-PCR. KCa currents in eGFP-positive astrocytes were determined in situ using whole-cell patch clamp electrophysiology. The contribution of KCa3.1 to neurovascular coupling was investigated in pharmacological experiments using electrical field stimulatio...
Spontaneous and ultraviolet-induced changeabilities of wine yeasts from the killer state to sensitive one have been studied. Observed often spontaneous changes of killer and neutral phenotypes under laboratory store conditions as well as high mutation frequency of genetic elements responsible for the killer indication on ultraviolet irradiation testify that often encounterability in nature and in the production of sensitive yeasts is attributed to high frequency of mutation changes of the killer and neutral phenotypes to the sensitive state.
We discuss the initial development of a concentrator device based on the GaInP/GaAs monolithic tandem cell structure. The very high one-sun efficiency of this device, coupled with its characteristic low operating current, make this a promising candidate for use under high concentration. Test results for a prototype device are presented. This device achieves an efficiency of 29.5% at a concentration of 102 suns.
BackgroundInfertility affects ∼20% of couples in Europe and in 50% of cases the problem lies with the male partner. The impact of damaged DNA originating...Full Text Available
This dissertation reports on the application of numerical optimization techniques as applied to fuel cell simulation and design. Due to the "multi-physics" inherent in a fuel cell, which results in a highly coupled and non-linear behavior, an experimental program to analyze and improve the performance of fuel cells is extremely difficult. This program applies new optimization techniques with computational methods from the field of aerospace engineering to the fuel cell design problem. After an overview of fuel cell history, importance, and classification, a mathematical model of solid oxide fuel cells (SOFC) is presented. The governing equations are discretized and solved with computational fluid dynamics (CFD) techniques including unstructured meshes, non-linear solution methods, numerical derivatives with complex variables, and sensitivity ...
For optimal performances, proton exchange membrane fuel cells require fine water and thermal management. Accurate modelling of the physical phenomena occurring in the fuel cell is a key issue to improve fuel cell technology. Here, an analytic steady state diphasic 2D model of heat and mass transfer is presented. Through this model, the aim of this work is to study the influence of local events on the global performances of a fuel cell. A part of the complete model is a microscopic representation of the coupling between water transport and charge transfers in the electrodes. The thickness of the liquid layer around the reactive agglomerates is deduced from the saturation. The evolution of the quantity of water within the catalyst layer is monitored and its influence on the global performanc...
A range of 6-substituted imidazo[1,2-a]pyridines were synthesized using a multicomponent coupling reaction. Most of these compounds were found to exhibit excellent activity against the colon cancer cell lines HT-29 and Caco-2, whilst not showing significant toxicity against white blood cells. Our studies have shown that the proteolytic phase of apoptosis was initiated 2 h after treatment with these imidazo-[1,2-a]pyridines. The data suggests that the imidazo[1,2-a]pyridine-induced cell death in HT-29 and Caco-2 cells is mediated via pathway(s) that include the release of cytochrome c from the mitochondria to the cytosol and the activation of caspase 3 and caspase 8.
Two overlapping cDNA clones encoding human DNA topoisomerase II were identified by two independent methods. In one, a human cDNA library in phage {lambda} was screened by hybridization with a mixed oligonucleotide probe encoding a stretch of seven amino acids found in yeast and Drosophila DNA topoisomerase II; in the other, a different human cDNA library in a {lambda}gt11 expression vector was screened for the expression of antigenic determinants that are recognized by rabbit antibodies specific to human DNA topoisomerase II. The entire coding sequences of the human DNA topoisomerase II gene were determined from these and several additional clones, identified through the use of the cloned human TOP2 gene sequences as probes. Hybridization between the cloned sequences and mRNA and genomic DNA indicates that the human enzyme is encoded by a single-copy gene. The location of the gene was mapped to chromosome 17q21-22 by in situ hybridization of a cloned fragment to ...
The LANL 2.5-cell, normal-conducting radio-frequency (NCRF) injector has been fabricated. We present initial results of low-power RF measurements (cavity Q, cavity field map, coupling beta, etc.) of the NCRF injector. The measured cavity Q and relative fields are found to be in good agreement with the design calculations and earlier measurements of Glidcop properties. However, the coupling beta of the ridge-loaded waveguides is found to be significantly higher than the design point. The impact of these low-power measurement results on the planned high-power RF and electron beam tests will be discussed.
The effects of atrial natriuretic peptide (ANP), oxytocin (OT) and vasopressin (AVP) on guanylate cyclase activity and cyclic GMP accumulation were examined, since these hormones appear to be intimately associated with blood pressure and intravascular volume homeostasis. ANP was found to increase cyclic GMP accumulation in ten cell culture systems, which were derived from blood vessels, adrenal cortex, kidney, lung, testes and mammary gland. ANP receptors were characterized in intact cultured cells using {sup 125}I-ANP{sub 8-33}. Specific {sup 125}I-ANP binding was saturable and of high affinity. Scratchard analysis of the binding data for all cell types exhibited a straight line, indicating that these cells possessed a single class of binding sites. Despite the presence of linear Scatchard plots, these studies demonstrated that cultured cells possess two functionally and physically ...
The Sirtuins are a family of orthologues of yeast Sir2 found in a wide range of organisms from bacteria to man. They display a high degree of conservation between species, in both sequence and function,...Full Text Available
1. A high degree of homology in the positions of tyrosine residues in glyceraldehyde 3-phosphate dehydrogenase from lobster and pig muscle, and from yeast, prompted an examination of the reactivity...Full Text Available
The stability of a symmetric tandem mirror with hot-electron end plugs against low-frequency modes is investigated using a model first proposed by Baldwin. The Baldwin instability, which is due to the coupling of a negative-energy mode in the plug and a shear Alfven mode in the center cell, is confirmed. It is found that this instability is confined to small ranges of value of L/sub c/, the length of the center cell. Under modest restriction of parameters, the unstable regions in L/sub c/ impose little limitation on L/sub c/.
A CO/sub 2/ laser chain able to supply approx.=30 MW on a single mode TEM/sub 00/ is described. The coupling of a modified Lumonics 101 module with a low-pressure cell constitues the oscillator and two further Lumonics 103 stages two amplifiers. The final pulse achieves the energy of 4.0 J with 90% of this energy in a peak of 100 ns FWHM.
We report that the fission yeast nucleoporin Nup124p is required for the nuclear import of both, retrotransposon Tf1-Gag as well as the retroviral HIV-1 Vpr. Failure to import Tf1-Gag into the nucleus...Full Text Available
Toxin-secreting “killer” yeasts were initially identified >40 years ago in Saccharomyces cerevisiae strains infected with a double-stranded RNA “killer”...Full Text Available
Fission yeast S. pombe is assumed to be a good model for cloning of human DNA repair genes, because human gene is normally expressed in S. pombe and has a very similar protein sequence to yeast protein. We have tried to elucidate the DNA repair mechanisms of S. pombe as a model system for those of mammals. (J.P.N.)
Yeast arginyl-tRNA synthetase recognizes the non-modified wild-type transcripts derived from both yeast tRNA(Arg) and tRNA(Asp) with equal efficiency. It discriminates its cognate natural substrate,...Full Text Available
Histone-beta-galactosidase protein fusions were used to identify the domain of yeast histone 2B, which targets this protein to the nucleus. Amino acids 28 to 33 in H2B were required for nuclear localization...Full Text Available
Transcription activation of sulfur metabolism in yeast is dependent on two DNA binding factors, the centromere binding factor 1 (Cbf1) and Met4. While the role of Met4 was clearly established by showing...Full Text Available
Suicide substrate β, γ-bidentate Rh(III)ATP (RhATP) was used to map the metal ion-binding site in yeast phosphoglycerate kinase (PGK). Cleavage of the RhATP-inactivated enzyme with...Full Text Available
A three-dimensional mathematical thermo-fluid model coupling the electrochemical kinetics with fluid dynamics was developed to simulate the heat and mass transfer in planar anode-supported solid oxide fuel cell (SOFC). The internal reforming reactions and electrochemical reactions of carbon monoxide and hydrogen in the porous anode layer were analyzed. The temperature, species mole fraction, current density, overpotential loss and other performance parameters of the single cell unit were obtained by a commercial CFD code (Fluent) and external sub-routine. Results show that the current density produced by electrochemical reactions of carbon monoxide cannot be ignored, the cathode overpotential loss is the biggest one among the three overpotential losses, and that the proper decrease of the operating voltage leads to the increase of the current density, PEN structure temperature, fuel utilization factor, fuel efficiency and ...
In this paper we develop an analytical framework for the study of electrochemical impedance of mixed ionic and electronic conductors (MIEC). The framework is based on first-principles and it features the coupling of electrochemical reactions, surface transport and bulk transport processes. We utilize this work to analyze two dimensional systems relevant for fuel cell science via finite element method (FEM). Alternate current Impedance Spectroscopy (IS) of a ceria symmetric cell is simulated near equilibrium condition (zero bias) for a wide array of working conditions including variations of temperature and $H_2$ partial pressure on a two dimensional fuel cell sample with patterned metal electrodes. The model shows agreement of IS curves with the experimental literature with the relative error on the impedance being consistently below 2%. Important two-dimensional effects such the effects of thickness ...
The promising use of mesenchymal stromal cells (MSC) in regenerative technologies accounts for necessity of detailed study of their physiology. Proliferation and differentiation of multipotent cells often involve changes in their metabolic state. In the present study, we analyzed the expression of ATP-sensitive potassium (K"A"T"P) channels in MSC and upon in vitro differentiation. K"A"T"P channels are present in many cells and regulate a variety of cellular functions by couplingcell metabolism with membrane potential. Kir6.1, Kir6.2 and SUR2A were expressed in undifferentiated MSC, whereas SUR2B and SUR1 were not detected on cDNA and protein level. Upon adipogenic differentiation Kir6.1 and SUR2A showed a significant reduction of the amount of mRNA by 84% and 95%, respectively, whereas Ki...
The endothelin-B (ETB) receptor is a G-protein-coupled receptor that binds endothelin ligands and is essential for the development of epidermal melanocytes and enteric neurons. Recent reports indicate that ETB is localized to nuclei in cardiac ventricular myocytes, although it has been thought that ETB is localized mainly on the plasma membrane. It remains unknown, however, whether this unique distribution of ETB occurs in other tissues. To elucidate the subcellular distribution of ETB in the intestine, we performed immunofluorescence of ETB in mouse intestine using a specific antibody. ETB-like immunoreactivity was detected in both the mucosal and muscle layers. In the mucosal layer, villous epithelial cells, stromal cells of the lamina propria, and cryptic cells were immunostained. Subcellularly, ETB is localized mainly to the nuclei of villous epithelial cells. In the muscle ...
In this dissertation, we design and analyze efficient numerical methods for obtaining accurate solutions to model problems arising in fuel cells. A basic fuel cell model consists of five principles of conservation, namely, mass, momentum, species, charges (electrons and ions), and thermal energy. Overall, transport equations couple with electrochemical processes through source terms to describe reaction kinetics and electro-osmotic drag in the polymer electrolyte. To model multiphase species transport in the porous media and the gas channel of fuel cells, we consider a multiphase mixture model framework. The diffusivity of the two-phase mixture water conservation equation in this model is nonlinear, discontinuous, and degenerate. To handle this difficulty, we developed efficient and fast nonlinear iterative solvers based on the Kirchhoff transformation and nonlinear Dirichlet-Neumann domain ...
In the Joule II project JOU2-CT 94-0428 `Development and Testing of Stand-Alone small-size Solar Photovoltaic-Hydrogen power Systems (SAPHYS)`, different design configurations are compared and discussed. In this paper we present some of the proposed design configurations and discuss their benefits and drawbacks. Simplified expressions for system efficiency for the different configurations are presented. These expressions are based on average efficiencies for the solar cells, the electrolyzer, the batteries, the hydrogen storage and the fuel cells. Mean fractions of energy passing through the energy storages are also assumed. From considerations in the paper one conclusion becomes apparent, i.e. the direct use of the energy should be maximized. Another conclusion is that one of the most important factors in Solar Photovoltaic Hydrogen Power Systems is the solar cell efficiency. This point seems to be lost in typical projects ...
Zinc-fingers, which widely exist in eukaryotic cell and play crucial roles in life processes, depend on the binding of zinc ion for their proper folding. To computationally study the zinc coupled folding of the zinc-fingers, charge transfer and metal induced protonation/deprotonation effects have to be considered. Here, by attempting to implicitly account for such effects in classical molecular dynamics and performing intensive simulations with explicit solvent for the peptides with and without zinc binding, we investigate the folding of the Cys2His2 type zinc-finger motif and the coupling between the peptide folding and zinc binding. We find that zinc ion not only stabilizes the native structure, but also participates in the whole folding process. It binds to the peptide at early stage of folding, and directs or modulates the folding and stabilizations of the component beta-hairpin and alpha-helix. Such a crucial role of ...
Eight culture-collection yeast strains of various species and five newly isolated stains were tested for both growth in olive oil extraction effluents and fermentation of the sugars in the same media. The culture-collection yeast strains did not grow in an effluent containing 2.86% sugar (w/v), 8 g/litre phenolic substances, 4.58 g/litre titratable acidity and pH 4.96, whereas the newly isolated strains of Torulopsis sp. MK-1, Saccharomyces norbensis MC-1, S. oleaceus MC-2 and S. oleaginosus grew well and fermented the sugars. In the medium mentioned above, they produced alcohol in amounts of 1.63 to 1.38%, respectively. None of the yeasts grew in an olive oil extraction effluent vacuum-concentrated to over 13-14% of dry matter. The strain of T. sp. MK-1 showed a higher stability.
Biosorption of uranium by residual biomass from The Old Bushmill`s Distillery Co. Ltd., Bushmills, Co. Antrim, Northern Ireland, following exposure to short and intense electric pulses has been examined. The biomass was prepared from the distillery spent wash and consisted of non-viable yeast and bacterial cells. As shown previously, untreated biomass had a maximum biosorption capacity of 170 mg uranium/g dry weight biomass. When biosorption reactions were placed between two electrodes and exposed to electric pulses with field strengths ranging from 1.25-3.25 kV/cm at a capacitance of 25 {mu}F, biosorption increased from 170 mg of uranium to 275 mg uranium/g dry weight biomass. The data were obtained from biosorption isotherm analyses and taken as the degree of biosorption at residual uranium concentrations of 3 mM. In addition, when the capacitance of the electric pulses increased from 0.25 {mu}F to 25 {mu}F at a fixed pulse field strength the ...
The thermal modeling of electrochemical batteries is today an integral part of the design and validation operations of new products. The Li-ion pair allows to increase the power density of batteries but leads to higher heat fluxes during charging-output cycles. Thus, the thermal control has become more crucial and requires the use of modeling. SAFT and TSR companies are involved in this approach and use the ESACAP software. This paper presents this software which uses a nodal method for the modeling of the coupled thermal and electrical processes that take place inside elementary cells and batteries. (J.S.)
The theoretical hardness against total dose of the six-transistor SRAM cell is investigated in detail. An explicit analytical expression of the maximum tolerable threshold voltage shift is derived for two cross-coupled inverters. A numerical method is used to explore the hardness of the read and write operations. Both N- and P-channel access transistors designs are considered and their respective advantages are compared. The study points out that the radiation hardness mainly relies on the technology. Results obtained with the very robust Gate-All-Around process are finally presented.
Current multi-scale computational models of ventricular electromechanics describe the full process of cardiac contraction on both the micro- and macro- scales including: the depolarization of cardiac cells, the release of calcium from intracellular stores, tension generation by cardiac myofilaments, and mechanical contraction of the whole heart. Such models are used to reveal basic mechanisms of cardiac contraction as well as the mechanisms of cardiac dysfunction in disease conditions. In this paper, we present a methodology to construct finite element electromechanical models of ventricular contraction with anatomically accurate ventricular geometry based on magnetic resonance and diffusion tensor magnetic resonance imaging of the heart. The electromechanical model couples detailed repres...
'Full text:' The use of fuel cell technology in military applications will depend on safe, high energy density systems being developed. An important part of using this technology is also the development of alternative hydrogen producing fuels with high energy densities and are easy to transport. Fuel cells are now a very large R and D effort for several military applications around the world. The major reason is because of the high power demands needed requires electrical energy sources that far exceed the capabilities of batteries currently being fielded for portable applications. Fuel cells are regarded as highly efficient, tactical energy converters that can be adapted for wide range of power requirements. They are potentially the lowest weight power source when coupled with batteries or capacitors to form hybrid systems. Generally electrical power is needed to support a number of applications from ...
In the advance of fuel cell electric vehicles (EV), hybrid electric vehicles (HEV) can contribute to reduced emissions and energy consumption of personal cars as a short term solution. Trade-offs reveal better emission control for series hybrid vehicles, while parallel hybrid vehicles with different drive trains may significantly reduce fuel consumption as well. At present, costs and marketing considerations favor parallel hybrid vehicles making use of small, high power batteries. With ultra high power density cells in development, exceeding 1 kW/kg, high power batteries can be provided by adapting a technology closely related to consumer cell production. Energy consumption and emissions may benefit from regenerative braking and smoothing of the internal combustion engine (ICE) response as well, with limited additional battery weight. High power supercapacitors may assist the achievement of this goal. Problems to be solved ...
We are continuing to study the suitability of modified thermal-battery technology as a potential power source for geothermal borehole applications. Previous work focused on the LiSi/FeS{sub 2} couple over a temperature range of 350 C to 400 C with the LiBr-KBr-LiF eutectic, which melts at 324.5 C. In this work, the discharge processes that take place in LiSi/CsBr-LiBr-KBr eutectic/FeS{sub 2} thermal cells were studied at temperatures between 250 C and 400 C using pelletized cells with immobilized electrolyte. The CsBr-LiBr-KBr eutectic was selected because of its lower melting point (228.5 C). Incorporation of a quasi-reference electrode allowed the determination of the relative contribution of each electrode to the overall cell polarization. The results of single-cell tests and limited battery tests are presented, along with preliminary data for battery stacks tested in a simulated ...
The conversion of off-peak surplus electricity into peak electricity through an electrolyzer, hydrogen storage, and fuel cell energy storage system was discussed. Development efforts in high pressure alkaline electrolysis and Proton-Exchange Membrane (PEM) fuel cells have improved the near-term viability of these systems. Potential use of wind turbines and other renewable energy-based generation systems, through hydrogen-based energy storage, were discussed as a new supply of surplus electricity. An integrated set of nomographs were presented for providing quick estimates of peak electricity costs derived from an electrolyzer/hydrogen fuel cell system. The nomographs allowed first order cost comparisons of centralized versus distributed hydrogen energy systems considering trade-offs between production economies of scale and hydrogen storage and transport costs. Use of the nomographs to compare centralized and dispersed ...
The great advantage of the helical ionization cooling channel (HCC) is its compact structure that enables the fast cooling of muon beam 6-dimensional phase space. This compact aspect requires a high average RF gradient, with few places that do not have cavities. Also, the muon beam is diffuse and requires an RF system with large transverse and longitudinal acceptance. A traveling wave system can address these requirements. First, the number of RF power coupling ports can be significantly reduced compared with our previous pillbox concept. Secondly, by adding a nose on the cell iris, the presence of thin metal foils traversed by the muons can possibly be avoided. We show simulations of the cooling performance of a traveling wave RF system in a HCC, including cavity geometries with inter-cell RF power couplers needed for power propagation.
In this work, a three-dimensional multiphase non-isothermal model incorporated with a capillary-extended sub-model in gas channels is used to investigate the coupled phenomena of water and thermal transport in proton exchange membrane fuel cells. Distributions of water and temperature along the flow path in the channel are highlighted and the pros and cons of various operating temperatures are elaborated. In addition, this work also sheds light on the impacts of temperature variations of bipolar plates induced by non-uniform cooling conditions, which have been overlooked by most previous works. An important phenomenon of water distribution, dry-out at inlets and flooding at outlets (DIFO), is observed and this non-uniform distribution is revealed to be greatly influenced by the operating t...
Thermophotovoltaic (TPV) converters were developed and tested at the heat source operating temperature of 1,700 K. Rare-earth-doped yttrium aluminum garnet (YAG) and lutetium yttrium aluminum garnet (Lu, YAG) selective emitters, as well as a blackbody emitter, were coupled to InGaAs/InP photovoltaic (PV) cells and bandpass/infrared (IR) reflector filters. YAG-based selective emitters were adopted with Ho, Tm, and Er. PV cells had bandgaps of 0.51, 0.57, and 0.69 eV. Converter energy conversion efficiencies approaching 30%, as well as electrical output power densities near 2 W/cm{sup 2} were demonstrated. The overall performance of the filtered blackbody-based converter was found to be superior to the selective emitter YAG-based converters. The details of the measurements performed on the above converters and their individual components are presented.
It is planned to bulk-heat a unit cell of a fusion reactor solid-breeder blanket in a fission reactor to study thermo-mechanical and thermal-hydraulic properties of fusion blankets. This study investigates the neutronic feasibility of using the Power Burst Facility (PBF) for this purpose. Heating rates were calculated for a Li/sub 2/O experiment placed in the PBF test space. The ANISN code and a 56-group coupled neutron-gamma library based on FLUNG and VITAMIN C were used to compute the heating rates. The results show that an average heating rate level of 1-3 W/cc can be produced in PBF with a local power profile that should be typical of a fusion blanket unit cell.
An appropriate mathematical model can help researchers to simulate, evaluate, and control a proton exchange membrane fuel cell (PEMFC) stack system. Because a PEMFC is a nonlinear and strongly coupled system, many assumptions and approximations are considered during modeling. Therefore, some differences are found between model results and the real performance of PEMFCs. To increase the precision of the models so that they can describe better the actual performance, optimization of PEMFC model parameters is essential. In this paper, an artificial bee swarm optimization algorithm, called ABSO, is proposed for optimizing the parameters of a steady-state PEMFC stack model suitable for electrical engineering applications. For studying the usefulness of the proposed algorithm, ABSO-based results...
The Ty transposable elements of Saccharomyces cerevisiae form a heterogeneous family within which two broad structural classes (I and II) exist. The two classes differ by two large substitutions and...Full Text Available
Tropomyosin (Tm) is a conserved dimeric coiled-coil protein, which forms polymers that curl around actin filaments in order to regulate actomyosin function. Acetylation of the Tm N-terminal...Full Text Available
DNA methylation of cytosine residues is a widespread phenomenon and has been implicated in a number of biological processes in both prokaryotes and eukaryotes. This methylation occurs at the 5-position...Full Text Available
The exocyst is an evolutionarily conserved octameric complex involved in polarized exocytosis from yeast to humans. The Sec3 subunit of the exocyst acts as a spatial landmark for exocytosis through...Full Text Available
This annual review focuses on invertebrate model organisms, which continue to yield fundamental new insights into mechanisms of aging. This year, the budding yeast has been used to understand how asymmetrical...Full Text Available
Yeast Sir2 deacetylase is a component of the silent information regulator (SIR) complex encompassing Sir2/Sir3/Sir4. Sir2 is recruited to telomeres through Rap1, and this complex spreads into subtelomeric...Full Text Available
Mutant strains of the yeast Saccharomyces cerevisiae which lack functional Cu,Zn superoxide dismutase (SOD-1) do not grow aerobically unless supplemented with methionine. The molecular basis of this...Full Text Available
Sirtuins are highly conserved NAD+-dependent protein deacetylases and/or ADP-ribosyltransferases that can extend the lifespan of several lower model organisms including yeast, worms and flies....Full Text Available
SummaryThe general transcription factor TFIID is a large multi-subunit complex required for the transcription of most protein-encoding genes by RNA polymerase II. Taking advantage...Full Text Available
Three Legionella-like organisms were isolated from water from the cooling towers of two Australian institutions. The strains grew on buffered charcoal-yeast extract (BCYE) agar but not on BCYE agar...Full Text Available
Baker's yeast (Saccharomyces cerevisiae) has been genetically engineered to ferment the pentose sugar xylose present in lignocellulose biomass. One of the reactions controlling the...Full Text Available
The beneficial effect of improving yeast redox response by increasing thioredoxin levels has been shown. Decreased lipid and protein oxidation is reflected in an increased biomass yield. In addition,...Full Text Available
Calorie restriction (CR) induces a metabolic shift towards mitochondrial respiration; however, molecular mechanisms underlying CR remain unclear. Recent studies suggest that CR-induced mitochondrial...Full Text Available
Cryptococcus neoformans is a pathogenic yeast that often causes devastating meningoencephalitis in immunocompromised individuals. We have previously identified the C. neoformans...Full Text Available
A fuzzy-decision-making procedure is applied to find the optimal feed policy of a fed-batch fermentation process for fuel ethanol production using a genetically engineered Saccharomyces yeast 1400 (pLNH33). The policy consisted of feed flow rate, feed concentration, and fermentation time. The recombinant yeast 1400 (pLNH33) can utilize glucose and xylose simultaneously to produce ethanol. However, the parent yeast utilizes glucose only. A partially selective model is used to describe the kinetic behavior of the process. In this study, this partially selective fermentation process is formulated as a general multiple-objective optimal control problem. By using an assigned membership function for each of the objectives, the general multiple-objective optimization problem can be converted into a maximizing decision problem. In order to obtain a global solution, a hybrid method of differential evolution is introduced to solve ...
It was found that neither the enzymes of the grapes nor those of wine yeast Saccharomyces ellipsoideus strain 223 attacked the higher polysaccharides present in corn syrups. The alcohol...Full Text Available
Spinocerebellar ataxia 10 (SCA10) is an autosomal dominant disease caused by large-scale expansions of the (ATTCT)n repeat within an intron of the human ATXN10 gene. In contrast...Full Text Available
The delivery of proteins and organelles to the vacuole by autophagy involves membrane rearrangements that result in the formation of large vesicles called autophagosomes. The mechanism underlying autophagosome...Full Text Available
The programming of cellular networks to achieve new biological functions depends on the development of genetic tools that link the presence of a molecular signal to gene-regulatory activity. Recently,...Full Text Available
A high-throughput assay for enzyme activity has been developed that is reaction independent. In this assay, a small-molecule yeast three-hybrid system is used to link enzyme catalysis to transcription...Full Text Available
Several independent studies of bacterial degradation of nitrate ester explosives have demonstrated the involvement of flavin-dependent oxidoreductases related to the old yellow enzyme (OYE) of yeast....Full Text Available
DNA replication programs have been studied extensively in yeast and animal systems, where they have been shown to correlate with gene expression and certain epigenetic modifications. Despite the conservation...Full Text Available
BackgroundThe production of high yields of recombinant proteins is an enduring bottleneck in the post-genomic sciences that has yet to be addressed in a truly rational manner. Typically...Full Text Available
Botulism is caused by the botulinum neurotoxins (BoNTs), the most poisonous substance known. Because of the high potency of BoNT, development of diagnostic and therapeutic antibodies for botulism requires...Full Text Available
In the yeast Saccharomyces cerevisiae, a and α mating-type information is stored in transcriptionally silenced cassettes called HML and HMR....Full Text Available
Hyperphosphorylated and aggregated human protein tau constitutes a hallmark of a multitude of neurodegenerative diseases called tauopathies, exemplified by Alzheimer's disease. In spite of an enormous amount of research performed on tau biology, several crucial questions concerning the mechanisms of tau toxicity remain unanswered. In this paper we will highlight some of the processes involved in tau biology and pathology, focusing on tau phosphorylation and the interplay with oxidative stress. In addition, we will introduce the development of a human tau-expressing yeast model, and discuss some crucial results obtained in this model, highlighting its potential in the elucidation of cellular processes leading to tau toxicity.
BackgroundIn recent years, near-infrared fluorescence (NIRF)-labeled iron nanoparticles have been synthesized and applied in a number of applications, including the labeling of human cells for monitoring the engraftment process, imaging tumors, sensoring the in vivo molecular environment surrounding nanoparticles and tracing their in vivo biodistribution. These studies demonstrate that NIRF-labeled iron nanoparticles provide an efficient probe for cell labeling. Furthermore, the in vivo imaging studies show excellent performance of the NIR fluorophores. However, there is a limited selection of NIRF-labeled iron nanoparticles with an optimal wavelength for imaging around 800 nm, where tissue autofluorescence is minimal. Therefore, it is necessary to develop additional alternative NIRF-labeled iron nanoparticles for application in this area.ResultsThis study manufactured 12-nm DMSA-coated Fe3O4 nanoparticles labeled with a near-infrared ...
In our previous work, we demonstrated that biomass-generated producer gas can be converted to ethanol and acetic acid using a microbial catalyst Clostridium carboxidivorans P7{sup T}. Results showed that the producer gas (1) induced cell dormancy, (2) inhibited H{sub 2} consumption, and (3) affected the acetic acid/ethanol product distribution. Results of this work showed that tars were the likely cause of cell dormancy and product redistribution and that the addition of a 0.025{mu}m filter in the gas cleanup negated the effects of tars. C. carboxidivorans P7{sup T} can adapt to the tars (i.e. grow) only after prolonged exposure. Nitric oxide, present in the producer gas at 150ppm, is an inhibitor of the hydrogenase enzyme involved in H{sub 2} consumption. We conclude that significant conditioning of the producer gas will be required for the successful coupling of biomass-generated producer gas with fermentation to produce ...
Chromium electroplated AISI 316L stainless steel was nitrided using inductively coupled plasma (ICP) for application in the bipolar plate of a polymer electrolyte membrane fuel cell (PEMFC). A continuous and thin chromium nitride layer was formed at the surface of the samples after ICP nitriding for 2 h at 400 C. The interfacial contact resistance (ICR) and corrosion resistance in simulated PEMFC operating conditions were higher than the required values, while they varied with the applied dc bias voltage during the nitriding process. The ICR value decreased with an increase in bias voltage. Potentiodynamic polarization measurements showed that all of the nitrided samples had excellent corrosion resistance with a current density of {proportional_to}10{sup -7} A cm{sup -2} at the cathode. It was also found that the oxygen content at the surface was not increased after the corrosion test. X-ray diffractometry (XRD), field emission scanning ...
A comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S-adenosyl-L-methionine (SAM), and its metabolites, i.e., S-adenosylhomocysteine (SAH), adenosine (Ado), 5prime-deoxy-5prime-methylthioadenosine (MTA), adenine (Ade), S-adenosyl-methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed-phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7-T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05 M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell-free bacterial broths by solid-pha...
We have previously reported that FSH stimulates flux of 45Ca2+ into cultured Sertoli cells from immature rats via voltage-sensitive and voltage-independent calcium channels. In the present study, we show that this effect of FSH does not require cholera toxin (CT)- or pertussis toxin (PT)-sensitive guanine nucleotide binding (G) protein or activation of adenylate cyclase (AC). Significant stimulation of 45Ca2+ influx was observed within 1 min, and maximal response (3.2-fold over basal levels) was achieved within 2 min after exposure to FSH. FSH-stimulated elevations in cellular cAMP paralleled increases in 45Ca2+ uptake, suggesting a possible coupling of AC activation to 45Ca2+ influx. (Bu)2cAMP, however, was not able to enhance 45Ca2+ uptake over basal levels at a final concentration of 1000 microM, although a concentration-related increase in androstenedione conversion to estradiol was evident. Exposure of Sertoli cells to ...
A recurrent idea in the study of complex systems is that optimal information processing is to be found near bifurcation points or phase transitions. However, this heuristic hypothesis has few (if any) concrete realizations where a standard and biologically relevant quantity is optimized at criticality. Here we give a clear example of such a phenomenon: a network of excitable elements has its sensitivity and dynamic range maximized at the critical point of a non-equilibrium phase transition. Our results are compatible with the essential role of gap junctions in olfactory glomeruli and retinal ganglionar cell output. Synchronization and global oscillations also appear in the network dynamics. We propose that the main functional role of electrical coupling is to provide an enhancement of dynamic range, therefore allowing the coding of information spanning several orders of magnitude. The mechanism could provide a microscopic neural basis for ...
Electric Fuel Ltd. is engaged in the design, development and commercialization of its proprietary zinc/air battery technology for electric vehicles, consumer electronic products and defence applications. To meet the challenging requirements for propelling an all-electric bus, the Vehicle Division sought a unique solution: an all electric battery-battery hybrid propulsion system. The high energy zinc/air battery is coupled with a high-power auxiliary battery. The combined system offers zero emission, high power and long range in an economically viable package. The consumer battery group has developed a high power primary zinc/air cell aimed at cellular phone users, offering extended use, convenience and low cost. (orig.)
AbstractBackground In recent years nano-metaloxides which easily penetrate into the cells with special interest due to their higher chemical reactivity as compared to that of similar materials in the bulk form. Of particular interest are nano-TiO2 and ZnO, which have been widely used for their bactericidal and anticancerous properties. Purpose The aim of the present study was to examine the bactericidal properties of nano-TiO2 and ZnO combined with visible light on S. aureus and S. epidermitis, known for their high prevalence in infected wounds. Study Using the technique of electron-spin resonance (ESR) coupled with spin trapping, we examined the ability of TiO2 and ZnO nanoparticle suspensions in water to produce reactive oxygen species (ROS) with and without visible light irradiation. Th...
Searches for permanent electric-dipole moments (EDM) of atoms provide important constraints on competing extensions to the standard model of elementary particles. Recently proposed experiment with liquid $^{129}$Xe [M.V. Romalis and M.P. Ledbetter, Phys. Rev. Lett. \\textbf{87}, 067601 (2001)] may significantly improve present limits on the EDMs. To interpret experimental data in terms of CP-violating sources, one must relate measured atomic EDM to various model interactions via electronic-structure calculations. Here we study density dependence of atomic EDMs. The analysis is carried out in the framework of the cell model of the liquid coupled with relativistic atomic-structure calculations. We find that compared to an isolated atom, the EDM of an atom of liquid Xe is suppressed by about 40%.
Apelin is a peptide known as the ligand of the G-protein-coupled receptor APJ. Several active apelin forms exist such as apelin-36, apelin-17, apelin-13, and the pyroglutamated form of apelin-13. Apelin and APJ are expressed in the central nervous system, particularly in the hypothalamus and in many peripheral tissues. Apelin has been shown to be involved in the regulation of cardiovascular and fluid homeostasis, food intake, cell proliferation, and angiogenesis. In addition to be an ubiquitous peptide, apelin is also produced and secreted by adipocytes and thus considered as an adipokine. This has opened a new field of investigation establishing a link between apelin and metabolic disorders (obesity, type 2 diabetes, etc.) which is the focus of the present review. Several studies, but not...
This dissertation is concerned with the development, experimental diagnostics and mathematical modelling and simulation of polymer electrolyte fuel cells (PEFC). The central themes throughout this thesis are the closely interlinked phenomena of mass and charge transfer. In the face of developing a PEFC system for vehicle propulsion these phenomena are scrutinized on a broad range of relevant scales. Starting from the material related level of the membrane and the gas diffusion layer (GDL) we turn to length scales, where structural features of the cell additionally come into play. These are the scale of flow channels and ribs, the single cell and the cell stack followed by the cell, stack, and system development for an automotive power train. In Chapter 3 selected fundamental material models and properties, respectively, are explored that are crucial for the mathematical modelling ...
Yeast artificial chromosome (YAC) libraries have been difficult to construct with average insert sizes >400 kilobase pairs when DNA is size-fractionated in low-melting-point agarose. By using yeast chromosomes in mock cloning experiments, the authors found that polyamines should be present whenever agarose containing high molecular weight DNA is melted to protect DNA from degradation. By incorporating polyamines during the cloning procedure, they constructed YAC libraries from mouse and human DNA with average insert sizes of 700 and 620 kilobase pairs, respectively. Several genome equivalents of these YAC libraries were replicated onto the surface of many duplicate agar plates using a 40,000 multipin transfer device. High-density filter replicas were screened by hybridization, and 70 mouse YAC clones from 31 loci and 132 human YAC clones from 49 loci were isolated.
Homology analyses of the protein sequences of chicken liver and rat mammary gland fatty acid synthases were carried out. The amino acid sequences of the chicken and rat enzymes are 67% identical. If conservative substitutions are allowed, 78% of the amino acids are matched. A region of low homologies exists between the functional domains, in particular around amino acid residues 1059-1264 of the chicken enzyme. Homologies between the active sites of chicken and rat and of chicken and yeast enzymes have been analyzed by an alignment method. A high degree of homology exists between the active sites of the chicken and rat enzymes. However, the chicken and yeast enzymes show a lower degree of homology. The DADPH-binding dinucleotide folds of the {beta}-ketoacyl reductase and the enoyl reductase sites were identified by comparison with a known consensus sequence for the DADP- and FAD-binding dinucleotide folds. The active sites of all of the enzymes ...
In response to a heat shock, the yeast Saccharomyces cerevisiae undergoes a large increase in its resistance to heat and, by the induction of its recombinational DNA repair capacity, a corresponding increase in resistance to radiation. Yeast which lack mitochondrial DNA, mitochondria-controlled protein synthetic apparatus, aerobic respiration, and electron transport (rho/sup 0/ strain) were used to assess the role of O/sub 2/, mitochondria, and oxidative processes controlled by mitochondria in the induction of these resistances. We have found that rho/sup 0/ yeast grown and heat shocked in either the presence or absence of O/sub 2/ are capable of developing both radiation and heat resistance. We conclude that neither the stress signal nor its cellular consequences of induced heat and radiation resistance are directly dependent on O/sub 2/, mitochondrial DNA, or mitochondria-controlled protein synthetic or oxidative ...
Cytosine methylation in DNA is a major epigenetic signal, and plays a central role in propagating chromatin status during cell division. However the mechanistic links between DNA methylation and histone methylation are poorly understood. A multi-domain protein UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1) is required for DNA CpG maintenance methylation at replication forks, and mouse UHRF1-null cells show enhanced susceptibility to DNA replication arrest and DNA damaging agents. Recent data demonstrated that the SET and RING associated (SRA) domain of UHRF1 binds hemimethylated CpG and flips 5-methylcytosine out of the DNA helix, whereas its tandom tudor domain and PHD domain bind the tail of histone H3 in a highly methylation sensitive manner. We hypothesize that UHRF1 brings the two components (histones and DNA) carrying appropriate markers (on the tails of H3 and hemimethylated CpG sites) ready to be assembled into a ...
An advanced process for the separation of hydrogen sulfide (H{sub 2}S) from coal gasification product streams through an electrochemical membrane is being developed. H{sub 2}S is removed from the syn-gas stream, split into hydrogen, which enriches the exiting syn-gas, and sulfur, which is condensed from an inert sweep gas stream. The process allows removal of H{sub 2}S without cooling the gas stream and with negligible pressure loss through the separator. The process is made economically attractive by the lack of need for a Claus process for sulfur recovery. Membrane manufacturing coupled with full-cell experimentation was the primary focus this quarter. A tape-casted zirconia membrane was developed and utilized in one full-cell experiment (run 25); run 24 utilized a fabricated membrane purchased from Zircar Corporation. Results are discussed.
An /alpha//sub 2/-adrenergic receptor subtype has been cloned from a human kidney cDNA library using the gene for the human platelet /alpha//sub 2/-adrenergic receptor as a probe. The deduced amino acid sequence resembles the human platelet /alpha//sub 2/-adrenergic receptor and is consistent with the structure of other members of he family of guanine nucleotide-binding protein-coupled receptors. The cDNA was expressed in a mammalian cell line (COS-7), and the /alpha//sub 2/-adrenergic ligand (/sup 3/H)rauwolscine was bound. Competition curve analysis with a variety of adrenergic ligands suggests that this cDNA clone represents the /alpha//sub 2/B-adrenergic receptor. The gene for this receptor is on human chromosome 4, whereas the gene for the human platelet /alpha//sub 2/-adrenergic receptor (/alpha//sub 2/A) lies on chromosome 10. This ability to express the receptor in mammalian cells, free of other adrenergic receptor ...
Whilst unwashed preparations of biomass from a local brewery had an apparent maximum biosorption capacity for uranium of 360 mg/g (dry weight biomass) washing reduced this maximum to 150 mg/g. Homogenization of both biomass preparations and recovery of cellular debris had no significant effect on the maximum biosorption capacities although at lower equilibrium concentrations of uranium differences in the biosorption capacities were detected. When unwashed biomass was retained by a semi-permeable membrane 40% of uranium used in the experiments precipitated outside that membrane. Therefore a significant proportion of the uranium removed from solution, and previously attributed to biosorption by the yeast biomass, resulted from precipitation brought about by interaction with low molecular weight components loosely associated with the biomass. (Author).
Pectin rich cold stored spoiled fruits, vegetables and cold soils were screened and different pectinolytic isolates were obtained by enrichment culturing and ruthenium red plate assay. Among the primary isolates 10-15% were yeast isolates. Six isolates with higher zones of pectin hydrolysis were selected and tested for polygalacturonase (PGU) production at room temperature (25 degrees C) and at 5 degrees C. One isolate identified as Saccharomyces sp. with highest polygalacturonase activity at 5 degrees C was used for enzyme production using raw fruit pectins as substrates. The isolate was identified by preliminary cultural, morphological and sugar fermentation tests. PGU production was high in raw pectin substrates like orange peel (21 U/ml), apple peel (20 U/ml ), mango peel (19 U/ml), ...
Abstract Microbiological quality and biophenol content evolution was studied in minimally processed Thassos cv table olives by hot air dehydration under mild conditions (40C, 24-h, aw-=-0.893) and storage under characteristic packaging conditions (vacuum, 100% N2 and air) at 4 and 20C over a period of 180 days. No salt was used in the production line or packaging. The undesirable microorganisms (Enterobacteriaceae, Staphylococcus aureus, Bacillus, Clostridium) were undetectable until the end of the storage period. Also, modified atmospheres prevented fungal growth at both temperatures apart from the samples stored in air, in which Penicillium and Aspergillus spp. were identified. At 20C, a coexistence of mesophilic bacteria and yeasts occurred. At 4C, yeasts were the predominant microflora...
A 65-yr-old female developed cough, fever and dyspnoea following repeated exposure to a home ultrasonic humidifier. High-resolution computed tomography showed ground-glass opacity in both lung fields. Arterial blood gas analysis gave an oxygen tension of 8.38 kPa (63 Torr). Pulmonary function testing revealed restrictive ventilatory impairment with a reduction in the diffusing capacity. The diagnosis of extrinsic allergic alveolitis (EAA) was confirmed by radiographic findings, pathological evidence of alveolitis and reproductive development by a provocation test to the humidifier water. The yeast Debaryomyces Hansenii was the only microorganism cultured from the water of the humidifier. The double diffusion precipitating test and lymphocyte proliferative response was positive for an extract of D. Hansenii, providing evidence to incriminate this fungus. This is the first described case of EAA caused by D. Hansenii. PMID:12449192
The effects of dietary plant and yeast cerebroside (glucosylceramide), a major sphingolipid in plants and yeast, on atopic dermatitis (AD) like symptoms were investigated in a mouse model. After 7 wk of feeding with a diet containing maize glucosylceramide, plasma IgE levels became significantly lower and in contrast, the levels of interleukin (IL)-12, which induces cellular immunity, became significantly higher in the AD mice than in the controls. However, the sphingolipid constituents of the skin fraction in the maize glucosylceramide fed group did not contain sphingoid bases of plant origin, such as 8-unsaturated sphingoid bases. The results of the present study indicated that dietary plant glucosylceramide prevented AD-like symptoms in AD model mice via regulation of Th1/Th2 balance. P...
Long term integrated in situ experiments are performed in the HADES underground research facility (Mol, Belgium) in order to study the coupled reactivity between the different components of an underground repository for vitrified high level radioactive waste (HLW): glass, compacted clay, and stainless steel containers, at 90 degrees C and under gamma irradiation. Studies pertaining to the behaviour of silicon, a major element released during glass alteration, are presented here. Data collected from the integrated experiment, from simplified tests, and from modelling are put together, giving complementary information. The integrated experiment is used to investigate overall reactivity, whereas diffusion experiments coupled with modelling focused on the precipitation of silica in clay media. In the integrated in situ experiment, a bentonite clay (FoCa7) mixed with 5 wt.% of powdered glass frit was put in contact with U/Th-doped SON68 reference ...
We studied the effect of extracellular Ca"2"+ concentration ([Ca"2"+]_e) on adipocyte differentiation. Preadipocytes exposed to continuous [Ca"2"+]_e higher than 2.5 mmol/l accumulated little or no cytoplasmic lipid compared to controls in 1.8 mmol/l [Ca"2"+]_e. Differentiation was monitored by Oil Red O staining of cytoplasmic lipid and triglyceride assay of accumulated lipid, by RT-PCR analysis of adipogenic markers, and by the activity of glycerol-3-phosphate dehydrogenase (GPDH). Elevated [Ca"2"+]_e inhibited expression of peroxisome proliferator-activated receptor #gamma#, CCAAT/enhancer binding protein #alpha#, and steroid regulatory binding element protein. High [Ca"2"+]_e significantly inhibited differentiation marker expression including adipocyte fatty acid binding protein, and GPDH. The decrease in Pref-1 expression that accompanied differentiation also was prevented by high [Ca"2"+]_e. Treatment of 3T3-L1 cells with high [Ca"2"+]_e did not significantly ...
The hypothesis that intracellular Ca/sup 2 +/ is an essential component of the intracellular mechanism of insulin action in the adipocyte was evaluated. Cells were loaded with the Ca/sup 2 +/ chelator quin-2, by preincubating them with quin-2 AM, the tetrakis(acetoxymethyl) ester of quin-2. Quin-2 loading inhibited insulin-stimulated glucose transport without affecting basal activity. The ability of insulin to stimulate glucose uptake in quin-2-loaded cells could be partially restored by preincubating cells with buffer supplemented with 1.2 mM CaCl/sub 2/ and the Ca/sup 2 +/ ionophore A23187. These conditions had no effect on basal activity and omission of CaCl/sub 2/ from the buffer prevented the restoration of insulin-stimulated glucose uptake by A23187. Quin-2 loading also inhibited insulin-stimulated glucose oxidation and the ability of insulin to inhibit cAMP-stimulated lipolysis without affecting their basal ...
The hypothesis that intracellular Ca"2"+ is an essential component of the intracellular mechanism of insulin action in the adipocyte was evaluated. Cells were loaded with the Ca"2"+ chelator quin-2, by preincubating them with quin-2 AM, the tetrakis(acetoxymethyl) ester of quin-2. Quin-2 loading inhibited insulin-stimulated glucose transport without affecting basal activity. The ability of insulin to stimulate glucose uptake in quin-2-loaded cells could be partially restored by preincubating cells with buffer supplemented with 1.2 mM CaCl_2 and the Ca"2"+ ionophore A23187. These conditions had no effect on basal activity and omission of CaCl_2 from the buffer prevented the restoration of insulin-stimulated glucose uptake by A23187. Quin-2 loading also inhibited insulin-stimulated glucose oxidation and the ability of insulin to inhibit cAMP-stimulated lipolysis without affecting their basal activities. Incubation of ...
Ribosomal protein L1 from Saccharomyces cerevisiae binds 5S rRNA and can be released from intact 60S ribosomal subunits as an L1-5S ribonucleoprotein (RNP) particle. To understand the nature of the...Full Text Available
Because of variations in tRNA sequences in evolution, tRNA synthetases either do not acylate their cognate tRNAs from other organisms or execute misacylations which can be deleterious in vivo. We report...Full Text Available
In order to study the intragenic profiles of active transcription, we determined the relative levels of active RNA polymerase II present at the 3′- and 5′-ends of 261 yeast genes by...Full Text Available
BackgroundThe large sensitivity, high reproducibility and essentially unlimited dynamic range of real-time PCR to measure gene expression in complex samples provides the opportunity...Full Text Available
Chapter 5, describes some of the most important molecular methods used in the study of chromosome structure and function. The methods discussed include fragmentation of DNA, cloning, flow cytometry and chromosome sorting, is situ hybridization, polymerase chain reaction (PCR), and yeast artificial chromosomes (YACs). 18 refs., 3 figs., 1 tab.
DescriptionThis project is part of the BBSRCs special initiative on plant and microbial metabolomics. The project will primarily focus on the trichothecene mycotoxin producing Ascomycete fungus Fusarium graminearum (Fg) which causes ear blight disease of small grain cereals. The project aims to explore the metabolome of various wild-type and single gene deletion Fg strains and to compare some of these with the identical gene mutation in the budding yeast, S. cerevisiae (Sc) and the saprophytic filamentous [continued...
Procedures are described for the use of synthetic oligonucleotides for Southern blot experiments and gene bank screening, and the effect of various mismatches on the efficiency of hybridization is demonstrated. The following topics are discussed: sensitivity vs. specificity, hybridization of a 12-mer to the lambda endolysin gene; hybridization of oligonucleotide probes to the E. coli lac operator; hybridization of synthetic probes to the CYC1 gene of yeast; and cloning eucaryotic genes. (HLW)
The N1-methyl-Adenosine (m1A58) modification at the conserved nucleotide 58 in the TΨC loop is present in most eukaryotic tRNAs. In yeast, m1A58 modification...Full Text Available
Acyl-CoA:diacylglycerol acyltransferase (EC 2.3.1.20) is a membrane protein present mainly in the endoplasmic reticulum. It catalyzes the final and committed step in the biosynthesis of triacylglycerol,...Full Text Available
Compared to yeast esterase, fungal cutinase degraded butyl benzyl phthalate (BBP) far more efficiently; i.e., almost 60% of the BBP disappeared within 7.5 h. Also, the final chemical composition significantly...Full Text Available
Current investigations into the biological solubilization of coal with microorganisms focus on the production of solubilizing activity in fungi. Test organisms for this work include a species of the yeast Candida previously isolated from a lignite outcrop, and P. chrysosporium, a filamentous higher fungus which has played a major role in lignin biodegradation research. The studies described are primarily exploratory in nature, and are fundamental to the design of more sophisticated inquiries into the physiology of fungal coal solubilization.
Temperature-sensitive mutants defective in 60S ribosomal subunit protein L16 of Saccharomyces cerevisiae were isolated through hydroxylamine mutagenesis of the RPL16B gene and plasmid shuffling. Two...Full Text Available
Thin film solar cells and solar cell testing - photovoltaic cells, radiation damage to cadmium sulfide solar cells, and airplane testing of solar cells
Abstract The term -stem cell- most commonly refers to embryonic stem cells, particularly in the lay media; however, it also describes other cell types. A stem cell represents a cell of multi-lineage potential with the ability for self-renewal. It is now clear that the plasticity and immortality of a given stem cell will depend on what type of stem cell it is, whether an embryonic stem cell, a fetal-placental stem cell or an adult stem cell. Stem cells offer great promise as cell-based therapies for the future. With evolving technology, much of the socio-political debate regarding stem cells can now be avoided.
MAGMA is a FORTRAN computer code designed to viscous flow in in situ vitrification melt pools. It models three-dimensional, incompressible, viscous flow and heat transfer. The momentum equation is coupled to the temperature field through the buoyancy force terms arising from the Boussinesq approximation. All fluid properties, except density, are assumed variable. Density is assumed constant except in the buoyancy force terms in the momentum equation. A simple melting model based on the enthalpy method allows the study of the melt front progression and latent heat effects. An indirect addressing scheme used in the numerical solution of the momentum equation voids unnecessary calculations in cells devoid of liquid. Two-dimensional calculations can be performed using either rectangular or cylindrical coordinates, while three-dimensional calculations use rectangular coordinates. All derivatives are approximated by finite differences. The ...
Alkali metal doped double perovskites containing manganese and at least one of cobalt, iron and nickel are useful in the oxidative coupling of alkane to higher hydrocarbons.
The application of the large-bore direct injection high efficiency nebulizer (LB-DIHEN) for the determination of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in urine by inductively coupled plasma mass spectrometry (ICP-MS) is described. The LB-DIHEN is compared with the standard method using a concentric pneumatic nebulizer and cyclonic spray chamber. In addition to the toxicological significance of As, Cd, Pb, and Hg, these elements represent a cross-section of analytical issues including spectral interferences (e.g., {sup 40}Ar{sup 35}Cl{sup +} on {sup 75}As{sup +} and {sup 98}Mo{sup 16}O{sup +} on {sup 114}Cd{sup +}) and memory effects (Hg). In this study, the low sample consumption of the LB-DIHEN is used to reduce the volume of urine needed for analysis, and to reduce the volume of final diluted sample required for analysis. Eliminating the spray chamber and reducing the dead volume of the nebulizer reduces memory effects, especially for analytes ...
This paper presents an uplink capacity analysis and interference avoidance technique for a femtocell based two-tier DS-CDMA network using shared spectrum. Assuming randomly distributed macrocell users and femtocell base stations (BS), we evaluate a network-wide area spectral efficiency metric called the operating contour (OC) defined as the feasible combinations of the average macrocell users and femtocell BS per cell-site that meet a target outage constraint $\\epsilon$. A contribution of this work is an accurate characterization of the uplink outage probability taking cross-tier power control, path-loss and shadowing effects into account. We show that a time-hopped CDMA physical layer coupled with sectorized receive antennas shows dramatic performance improvements in both light and heavily loaded two-tier networks, relative to a split spectrum two-tier network with omnidirectional femtocell antennas. These results provide insights into design ...
The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field induction accelerator units are placed periodically along the length or the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have serious option for a 1 TeV /times/ 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron ...
Water transport in conifers occurs through single-celled tracheids that are connected to one another via intertracheid pit membranes. These membranes have two components: the porous margo, which allows water to pass through the membrane, and the impermeable torus, which functions to isolate gas-filled tracheids. During drought, tracheids can become air filled and thus hydraulically dysfunctional, a result of air entering through the pit membrane and nucleating cavitation in the water column. What are the hydraulic tradeoffs associated with cavitation resistance at the pit level, and how do they vary within the structural components of the intertracheid pit? To address these questions, we examined pit structure in 15 species of Cupressaceae exhibiting a broad range of cavitation resistances. Across species, cavitation resistance was most closely correlated to the ratio of the torus to pit aperture diameter but did not vary systematically with margo porosity. ...
Thin, lightweight, and flexible gas-diffusion electrodes (GDEs) based on freestanding entangled networks of single-walled carbon nanotubes (SWNTs) decorated with Ag nanoparticles (AgNPs) are tested as the air-breathing cathode in a zinc-air battery. The SWNT networks provide a highly porous surface for active oxygen absorption and diffusion. The high conductivity of SWNTs coupled with the catalytic activity of AgNPs for oxygen reduction leads to an improvement in the performance of the zinc-air cell. By modulating the pH value and the reaction time, different sizes of AgNPs are decorated uniformly on the SWNTs, as revealed by transmission electron microscopy and powder X-ray diffraction. AgNPs with sizes of 3-5 nm double the capacity and specific energy of a zinc-air battery as compared with bare SWNTs. The simplified, lightweight architecture shows significant advantages over conventional carbon-based GDEs in terms of weight, thickness and ...
Methylxanthines and their derivatives are antagonists at cell surface adenosine receptors. They report here a systematic study of xanthine structure-activity relationships which compares potency at two adenosine receptor subtypes, R/sub a/ and R/sub i/. Adenylate cyclase stimulation (R/sub a/ in platelet membranes) and inhibition (R/sub i/ in adipocyte membranes) were used as models of receptor activation. K/sub i/ values were obtained by Schild analysis. The orders of potency of the xanthines to attenuate the effects of adenosine analogues were similar to those previously reported. Earlier work utilizing radioligand binding (R/sub i/ and (/sup 3/H) cAMP formation (R/sub a/) claimed that IIX and PACPX are at least 10 and 400 fold, respectively, more potent at R/sub i/ than at R/sub a/. However, in their assays which utilize modulation of receptor-coupled adenylate cyclase, the xanthines show little specificity for either adenosine receptor ...
This thesis deals with the special electronic properties of the transition-metal aluminides. Following quasicrystals and their approximants it is shown that even materials with small elementary cells exhibit the same surprising effects. So among the transition-metal aluminides also semi-metallic and semiconducting compounds exist, although if they consist of classic-metallic components like Fe, Al, or Cr. These properties are furthermore coupled with a deep pseusogap respectively gap in the density of states and strongly covalent bonds. Bonds are described in this thesis by two eseential properties. First by the bond charge and second by the energetic effect of the bond. It results that in the caes of semiconducting transition-metal aluminides both a saturation of certain bonds and a bond-antibond alteration in the Fermi level is present. By the analysis of the near-order in form of the so-calles coordination polyeders it has been succeeded to ...
Human bone marrow mesenchymal stem cells (BM-MSC) are multipotent progenitor cells that have transient immunomodulatory properties on Natural Killer (NK) cells, Dendritic Cells (DC), and T cells. This...Full Text Available
This paper presents a summary of the first phase of the EPA project, which encompasses surveys of residues from industrial sources in Alexandria. Studies to date indicate that wastes from various industries can be recovered economically. Wastes such as tin cans, glass, wastepaper, and food residues from processing of fruits, starch, and beer are examples of reusable industrial wastes in Egypt. The results of experimental studies for reuse of residues from oil refining, starch and yeast processing, and steel pickling are presented. Spent clay from edible oil refining is currently discarded, causing both handling and disposal problems. This clay contains as much as 40% oil; 90% can be recovered by extraction. The recovered oil can be successfully used in soap production, and the spent clay can be reused in oil bleaching. Other examples include starch and yeast wastes, which can be used for animal feed, and spent pickling liquor, which can be used ...
In clause it is shown a method optimization of brake of forces in view of a bias road it is established, that in mountain conditions of loss of coupling weight of automobiles than 2-3 times concerning flat conditions therma are more. The degree of use of coupling weight in result use of a regulator of brake forces very much increases also efficiency of brake systems such a kind of automobiles is provided with definition of optimum factor of coupling at which value of loss of coupling weight is provided minimal
Papers in this book illustrate the utility of mineral biotechnology with respect to biobeneficiation, bioleaching, bioremediation and biomineralization. Papers of particular interest to the coal industry include: depression of pyrite flotation by yeast and bacteris (S.K. Kawatra and T.C. Eisele); desulfurization of coal by microbial flotation in a semicontinuous system (T. Nagaoka and others); biochemical removal of HAP precursors from coal - INEEL slurry column testing (K.S. Noah and G.J. Olson); microorganisms, biotechnology and acid rock drainage - emphasis on passive-biological control and treatment methods (N. Kuyucak); and utility of bioreagents in mineral processing (P. Somasundaran and others).
Scientists of the Institute of Wood Chemistry of the Latvian Academy of Sciences have developed two highly efficient processes for producing furfural, a feedstock for varnishes, synthetic resins and plastics. It is made of production wastes, including branches and small-dimension timber. By one process, the raw material is chipped, treated first with diluted sulphuric acid and then with steam heated to 250 degrees C. The other uses concentrated sulphuric acid as a catalyst. Besides furfural, this process also yields sugar solutions used in alcohol and nutrient yeast production.
Glabridin, an active constituent of Glycyrrhiza glabra roots, was found to be active against both yeast and filamentous fungi. Glabridin also showed resistance modifying activity against drug resistant mutants of Candida albicans at a minimum inhibitory concentration of 31.25-250 g/mL. Although the compound was reported earlier to be active against Candida albicans, but this is the first report of its activity against drug resistant mutants. Copyright Copyright 2009 John Wiley & Sons, Ltd.
Motivation: Automatic recognition of cell identities is critical for quantitative measurement, targeting and manipulation of cells of model animals at single-cell resolution. It has been...Full Text Available
We present a strong-weak coupling duality for quantum mechanical potentials. Similarly to what happens in quantum field theory, it relates two problems with inverse couplings, leading to a mapping of the strong coupling regime into the weak one, giving information from the nonperturbative region of the parameters space. It can be used to solve exactly power-type potentials and to extract deep information about the energy spectra of polynomial ones. We present a strong-weak coupling duality for quantum mechanical potentials. Similarly to what happens in quantum field theory, it relates two problems with inverse couplings, leading to a mapping of the strong coupling regime into the weak one, giving information from the nonperturbative region of the parameters space. It can be used to solve exactly power-type potentials and to extract deep information about the ...
A major goal in optomechanics is to observe and control quantum behavior in a system consisting of a mechanical resonator coupled to an optical cavity. Work towards this goal has focused on increasing the strength of the coupling between the mechanical and optical degrees of freedom; however, the form of this coupling is crucial in determining which phenomena can be observed in such a system. Here we demonstrate that avoided crossings in the spectrum of an optical cavity containing a flexible dielectric membrane allow us to realize several different forms of the optomechanical coupling. These include cavity detunings that are (to lowest order) linear, quadratic, or quartic in the membrane's displacement, and a cavity finesse that is linear in (or independent of) the membrane's displacement. All these couplings are realized in a single device with extremely low optical loss and can ...
We investigate the variation of the out-of-phase periodic rhythm produced by two chaotic neurons {bold (}Hindmarsh-Rose neurons [J. L. Hindmarsh and R. M. Rose, Proc. R. Soc. London B {bold 221}, 87 (1984)]{bold )} coupled by electrical and reciprocally synaptic connections. The exploration of a two-parametric bifurcation diagram, as a function of the strength of the electrical and inhibitory coupling, reveals that the periodic rhythms associated to the limit cycles bounded by saddle-node bifurcations, undergo a strong variation as a function of small changes of electrical coupling. We found that there is a scaling law for the bifurcations of the limit cycles as a function of the strength of both couplings. From the functional point of view of this mixed typed of coupling, the small variation of electrical coupling provides a high sensitivity for period ...
The use of a running coupling constant in renormalizable theories is well known, but the implementation of this idea for effective field theories with a dimensional coupling constant is in general less useful. Nevertheless there are multiple attempts to define running couplings including the effects of gravity, with varying conclusions. We sort through many of the issues involved, most particularly the idea of operator mixing and also the kinematics of crossing, using calculations in Yukawa and lambda phi^4 theory as illustrative examples. We remain in the perturbative regime. In some theories with a high permutation symmetry, such as lambda phi^4, a reasonable running coupling can be defined. However in most cases, such as Yukawa and gauge theories, a running coupling fails to correctly account for the energy dependence of the interaction strength. As a byproduct we also contrast ...
The interlayer exchange coupling between Co/Pt perpendicular-to-plane magnetized layers across a thin IrMn spacer layer was experimentally studied. In contrast to earlier studies on interlayer coupling through antiferromagnetic NiO, which revealed an oscillatory coupling behavior as a function of NiO thickness, a ferromagnetic coupling was observed here in the range of IrMn thickness between 0.6 and 1.5nm and antiferromagnetic between 1.5 and 2.5nm. The antiferromagnetic coupling is attributed to an orange peel magnetostatic mechanism whereas the ferromagnetic coupling is attributed to an out-of-plane polarization of the antiferromagnetic IrMn layer induced by the interfacial exchange interaction with the adjacent out-of-plane ferromagnetic layers. Measurements of hysteresis loops versus t...
We study the dynamical evolution of a scalar field coupling to Einstein's tensor in the background of a Reissner-Nordstroem black hole. Our results show that the coupling constant #eta# imprints in the wave dynamics of a scalar perturbation. In the weak coupling, we find that with the increase of the coupling constant #eta# the real parts of the fundamental quasinormal frequencies decrease and the absolute values of imaginary parts increase for fixed charge q and multipole number l. In the strong coupling, we find that for l#not =#0 the instability occurs when #eta# is larger than a certain threshold value #eta#_c which deceases with the multipole number l and charge q. However, for the lowest l=0, we find that there does not exist such a threshold value and the scalar field always decays for arbitrary coupling constant.
Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck (Piperaceae) is a medicinal plant traditionally used in Brazil to treat infectious diseases. The extracts obtained from the leaves of P. regnellii were investigated for their antifungal activities against the yeasts Candida albicans, C. krusei, C. parapsilosis, and C. tropicalis. The EtOAc extract presented gnificant activity against Candida albicans with MIC at 125 {mu}g mL{sup -1}, and a moderate activity against both C. krusei and C. parapsilosis with MIC at 500 {mu}g mL{sup -1}. Candida tropicalis was not inhibited by this extract at concentrations as high as 1000 {mu}g mL{sup -1}. Based on these findings, the EtOAc extract was fractionated by silica gel column chromatography into nine fractions. The hexane and CHCl{sub 3} fractions showed varied levels of antifungal activity against all test yeasts. Further column chromatography separation of the hexane fraction afforded the pure ...
Possible anomalous top-quark couplings induced by SU(2)xU(1) gauge-invariant dimension-6 effective operators were studied in the process of ttbar productions and decays at polarized #gamma##gamma# colliders. Two CP-violating asymmetries, a linear-polarization asymmetry and a circular-polarization asymmetry, were computed including both non-standard ttbar#gamma# and #gamma##gamma#H couplings. An optimal-observable analysis for the process #gamma##gamma##->#ttbar#->#l"#+-# was performed in order to estimate the precision for determination of all relevant non-standard couplings, including the anomalous tbW coupling.
It is shown that the method used for comparing theoretical and experimental results is erroneous and the values of the couple stress parameters obtained for blood flow are incorrect. A method for determining the couple stress parameters is presented. The computational work in the improved method is considerably less. It is observed that both the couple stress parameters are functions of concentration. An empirical relation between concentration and the stress parameters is obtained. The shear viscosity and non-dimensional axial velocity are functions of concentration. Some uses of determining the values of the couple stress parameters are suggested.
In cooling systems, an improved control of scale deposit and corrosion processes is a major challenge and an realistic evaluation tool for water treatments is of the utmost economic importance. In this study, a channel flow cell was used to allow in-situ electrochemical measurements in well defined electrolyte tube flowing conditions. An expression of the mass transfer towards the electrode was established where the diffusion-limited current is a function of Re{sup 1/3} in the laminar regime and was verified experimentally using the redox couples Fe[CN]{sub 6}{sup 4-}/ Fe[CN]{sub 6}{sup 3-} and O{sub 2}/OH{sup -}. This hydrodynamically controlled experimental device was developed to investigate scale deposit processes and to evaluate scale inhibitor efficiency using a electrochemical quartz crystal microbalance. Experiments were performed on three different waters, at various flow rates and temperatures. The efficiency of a well known ...
This study addresses the modeling of transdermal diffusion of drugs, to better understand the permeation of molecules through the skin, and especially the stratum corneum, which forms the main permeation barrier of the skin. In transdermal delivery of systemic drugs, the drugs diffuse from a patch placed on the skin through the epidermis to the underlying blood vessels. The epidermis is the outermost layer of the skin and can be further divided into the stratum corneum (SC) and the viable epidermis layers. The SC consists of keratinous cells (corneocytes) embedded in the lipid multi-bilayers of the intercellular space. It is widely accepted that the barrier properties of the skin mostly arises from the ordered structure of the lipid bilayers. The diffusion path, at least for lipophilic molecules, seems to be mainly through the lipid bilayers. Despite the advantages of transdermal drug delivery compared to other drug delivery routes such as oral dosing and ...
The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering ...
The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering ...
A fast and simple flow-through optosensor was designed and characterized for the direct screening of four tetracycline (TCC) antibiotics (tetracycline, oxytetracycline, chlortetracycline and doxycycline) in water and bovine milk samples. The proposed optosensor provides rapid binary yes/no overall responses, being appropriate for the screening of this family of antibiotics above or below a pre-set concentration threshold. The experimental set-up is based on a flow-injection manifold coupled on-line to a phosphorescence detector. Aliquots of the samples are pretreated with Eu(III) to form room temperature phosphorescent metal chelates and injected in the flow manifold. Those chelates are then on-line retained on a conventional flow-cell (packed with polymeric Amberlite XAD-4 particles) which is placed inside the cell holder of the phosphorimeter. After the emission is registered, the antibiotic-metal complexes are eluted ...
In this work the development of a third order scheme of finite differences centered in mesh is presented and it is applied in the numerical solution of those diffusion equations in multi groups in stationary state and X Y geometry. Originally this scheme was developed by Hennart and del Valle for the monoenergetic diffusion equation with a well-known source and they show that the one scheme is of third order when comparing the numerical solution with the analytical solution of a model problem using several mesh refinements and boundary conditions. The scheme by them developed it also introduces the application of numeric quadratures to evaluate the rigidity matrices and of mass that its appear when making use of the finite elements method of Galerkin. One of the used quadratures is the open quadrature of 4 points, no-standard, of Newton-Cotes to evaluate in approximate form the elements of the rigidity matrices. The other quadrature is that of 3 points of Radau that it is used to ...
It is well known that contact with metals can be responsible for allergic contact dermatitis; also, there is experimental evidence that nickel ions are readily available on the surface of used coins containing nickel and copper. The aim of this study was to prove that metal powders of nickel (Ni), cobalt (Co) and chromium (Cr) dispersed in synthetic sweat are oxidised into respective ions that can permeate the skin. Suspensions of 5 g of metal powder (Ni, Co and Cr) in 100 mL of synthetic sweat at pH 6.5 were prepared and shaken with a stirring plate at room temperature for 30 min. Human skin membranes were set up in Franz-diffusion cells and 2 mL of the freshly made suspension were applied to the outer surface of the skin for 24h. The appearance of metal ions in the aqueous receptor phase (NaCl 0.9%) was quantified by Electro Thermal Atomic Absorption Spectroscopy (ETAAS). Also, metals ions were analysed using Differential Pulse Polarography (DDP), Differential ...
We studied telomeric DNA in leukemic cells as well as in normal T cells, B cells, monocytes, polymorphonuclear leukocytes, and bone marrow hematopoietic progenitor cells. No marked differences were...Full Text Available
We present an update of the most stringent experimental bounds on the trilinear R-parity violating couplings. We then analyse bounds on the R-parity violating couplings at the unification scale by renormalising the weak scale bounds. We derive unification scale upper bounds upon the couplings which are broadly independent of the fermion mass texture assumed. The R-parity violating couplings are factors of two to five more severely bounded at the unification scale than at the electroweak scale. In the presence of quark mixing, a few of the bounds are orders of magnitude stronger than their weak scale counterparts due to new R-parity violating operators being induced in the renormalisation between high and low scales. These induced bounds are fermion mass texture dependent. New bounds upon the weak scale couplings are obtained by the requirement of perturbativity between the weak and ...
We analyze the nucleon axial-vector coupling to two loops in chiral perturbation theory. We show that chiral extrapolations based on this representation require lattice data with pion masses below 300 MeV.
A survey is given on the present status of the nucleon parton distributions and related precision calculations and precision measurements of the strong coupling constant {alpha}{sub s}(M{sup 2}{sub Z}). We also discuss the impact of these quantities on precision observables at hadron colliders. (orig.)
A detailed comparative assessment was made of the use of solid-phase-coupled antibodies in radioimmunoassay, by using an assay for human placental lactogen as a model system. The major advantages of...Full Text Available
Gastrin-releasing peptide receptor (GRPR), a member of the G protein-coupled receptor superfamily, has been utilized for receptor-mediated targeting of imaging and therapeutic agents; here we extend...Full Text Available
The catalytic effects of copper-aluminium-magnesium oxides in the oxidative coupling of phenylethyne is described. The importance of surface properties as a redox site are discussed.
The authors derive in full details the Hamiltonian formulation of the N = 1D = 10 supergravity coupled to super Yang-Mills theory. In particular, they present the explicit form of the first class constraints and compute the constraints gauge algebra.
Are economic resources related to relationship quality among young couples, and to what extent does this vary by relationship type? To answer these questions, we estimated regression models...Full Text Available
A Bragg waveguide consisting of multiple dielectric layers with alternating index of refraction becomes an excellent option to form electron accelerating structure powered by high power laser sources. It provides confinement of a synchronous speed-of-light mode with extremely low loss. However, laser field can not be coupled into the structure collinearly with the electron beam. There are three requirements in designing input coupler for a Bragg electron accelerator: side-coupling, selective mode excitation, and high coupling efficiency. We present a side coupling scheme using a distributed grating-assisted coupler to inject the laser power into the waveguide. Side coupling is achieved by a grating with a period on the order of an optical wavelength. The phase matching condition results in resonance coupling thus providing selective mode excitation capability. ...
We have investigated the properties of nerve cell precursors in hydra by analyzing the differentiation and proliferation capacity of interstitial cells in the peduncle of Hydra oligactis, which is a region of active nerve cell differentiation. Our results indicate that about 50% of the interstitial cells in the peduncle can grow rapidly and also give rise to nematocyte precursors when transplanted into a gastric environment. If these cells were committed nerve cell precursors, one would not expect them to differentiate into nematocytes nor to proliferate apparently without limit. Therefore we conclude that cycling interstitial cells in peduncles are not intermediates in the nerve cell differentiation pathway but are stem cells. The remaining interstitial cells in the peduncle are ...
We have used scale models to measure the predicted coupling of electromagnetic fields simulating the effects of high-altitude nuclear electromagnetic pulses (HEMP) on the interior surfaces of electronic components. Predictive tools for exterior coupling are adequate. For interior coupling, however, such tools are in their infancy. Our methodological approach combines analytical, computational, and laboratory techniques in a complementary way to take advantage of their separate strengths. Computer models are a promising tool, as they can be used to treat complex objects with arbitrary shapes, dielectrics, and cables, and multiple apertures. Laboratory tests can expand the domain of investigation even further.
A general analysis is presented of a photon storage cavity, coupled to free-electron laser (FEL) cavity. It is shown that if the coupling between the FEL cavity and the storage cavity is unidirectional (for example, a ring resonator storage cavity) then storage is possible, but that if the coupling is bi-directional then storage is not possible. Parameters are presented for an infra-red FEL storage cavity giving an order of magnitude increase in the instantaneous photon power within the storage cavity. 4 refs., 3 figs.
It is shown that low-frequency elastic vibrations of near-surface planar defects cause high-frequency ultrasonic radiation in surrounding air. The frequency conversion mechanism is concerned with contact nonlinearity of the defect vibrations and provides efficient generation of air-coupled higher-order ultraharmonics, ultrasubharmonics, and combination frequencies. The nonlinear air-coupled ultrasonic emission is applied for location and high-resolution imaging of damage-induced defects in a variety of solid materials.
In this paper, finite-difference time-domain method is used to research the transient electromagnetic pulse (EMP) coupling to the cylinder object which is shielded in another shielding cavity with a hole numerically. The different coupling effectiveness of three transient EMP is simulated. The distribution of the electric field in the shielding cavity and the current on the cavity are researched. The shielding effectiveness is evaluated. (authors)
A silicon solar cell assembly comprising a large, thin silicon solar cell bonded to a metal mount for use when there exists a mismatch in the thermal expansivities of the device and the mount.
Experiments were designed to elucidate whether or not the irradiated bone marrow cells receive any stimulation for the self-replication and differentiation from normal 'stromal' cell colonies in the bone marrow cell culture in vitro. When irradiated or unirradiated bone marrow cells were overlaid on the normal adherent cell colonies, the proliferation of haemopoietic stem cells was supported, the degree of the stimulation depending on the starting cellular concentration. There was, however, no significant changes in the concentration of either CFUs or CFUc regardless of the dose of irradiation on the bone marrow cells overlaid. This was a great contrast to the dose-dependent decrease of CFUs or CFUc within the culture in which both the stem cells and stromal cells were ...
Ethane oxidation was studied in ethane-grown resting cells (mycelia) of an Acremonium sp. and in cell-free preparations of such mycelia. From resting cell experiments evidence was found for a pathway...Full Text Available
In most adult tissues there reside pools of stem and progenitor cells inside specialized microenvironments referred to as niches. The niche protects the stem cells from inappropriate expansion...Full Text Available
... Fuel Cell Technologies Equipment on Environmental Expert Find and compare a variety of fuel cell technologies equipment on the world's largest environmental industry portal. View ...
Purpose.There is a paucity of neuron replacement studies for retinal ganglion cells. Given the complex phenotype of these neurons, replacement of ganglion cells may be impossible....Full Text Available
Cell cultures were prepared from lung tumors occurring in beagles following exposure to inhaled plutonium. Morphologic and growth characteristics of two of these cell lines are described.
We report the isolation of adherent, clonogenic, fibroblast-like cells with osteogenic and adipogenic potential from the blood of four mammalian species. These cells phenotypically resemble but are...Full Text Available
...The+Wiley+Encyclopedia+of+Packaging+Technology%2C+3rd+Edition FO21+Food+Packaging Wiley::The Wiley Encyclopedia of Packaging Technology, 3rd Edition WILEY ...US | HELP Home / Chemistry / Food Science & Technology / Food Processing, Production & Manufacture / Food Packaging / The Wiley Encyclopedia of Packaging Technology, 3rd Edition ...Manufacture Sensory Science Food Biotechnology Food Chemistry Food Engineering Related Titles Food Packaging Brewing Yeast and Fermentation by Chris Boulton, David Quain Food ...Editor) Journal of Food Process Engineering Journal of Food Processing and Preservation Packaging Research in Food Product Design and Development by Howard R. ...
Wound dressings impregnated with silver have a role to play in aiding to reduce both the dressing and wound microbial bioburden. It is therefore imperative that antimicrobial wound dressings have efficacy on a broad range of clinical significant microorganisms. Accordingly, this study aimed to determine the antimicrobial efficacy of a silver alginate dressing against 115 wound isolates that had been isolated routinely from patients at West Virginia University Hospital. Standardised corrected zones of inhibition (CZOIs) were performed on all clinical isolates. It was found that the silver alginate dressing was able to inhibit the growth of all microorganisms tested. In particular, the silver alginate dressing inhibited the growth of Candida albicans and yeasts with CZOI of 3-115 mm. All met...
Mono- and disubstituted novel derivatives of the heptaene nystatin analog 28,29-didehydronystatin A1 (S44HP, 1) were obtained by chemical modification of the exocyclic C-16 carboxyl and/or an amino group of mycosamine moiety. The strategy of preparation of mono- and double-modified polyene macrolides was based on the use of intermediate hydrophobic N-Fmoc (9-fluorenylmethoxycarbonyl) derivatives that facilitated the procedures of isolation and purification of new compounds. The antifungal activity of the new derivatives was first tested in vitro against yeasts and filamentous fungi, allowing the selection of the most active compounds that were subsequently tested for acute toxicity in mice. 2-(N,N-dimethylamino)ethylamide of 1 (2) and 2-(N,N-dimethylamino)ethylamide of N-fructopyranosyl-28...
Background: The environment preferred by Acanthamoeba trophozoites and the mechanism by which the amebae enters the cornea are not yet fully understood. A better understanding of the pathogenesis of this disease may help with prevention and treatment. Purpose: To define the preferred environments for Acanthamoeba survival and proliferation in vitro by examining the effect of tonicity, nutrient concentration, and free chlorine content on Acanthamoeba. Materials and methods: Human corneal isolates of Acanthamoeba castellanii and Acanthamoeba polyphaga trophozoites were cultured at 22^oC (room temperature) in PYG (peptone-yeast extract-glucose) medium. The effect of tonicity on amebae was determined by incubating trophozoites in sodium chloride solutions in concentrations ranging from 0% to 1...
Statistically based experimental designs were applied to screen and optimize the bioleaching of spent hydrocracking catalyst by Penicillium simplicissimum. Eleven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design. Four significant variables (pulp density, sucrose, NaNO"3, and yeast extract concentrations) were selected for the optimization studies. The combined effect of these variables on metal bioleaching was studied using a central composite design (CCD). Second-order polynomials were established to identify the relationship between the recovery percent of the metals and the four significant variables. The optimal values of the variables for maximum metals bioleaching were as follows: pulp density (4.0%, w/v), sucrose (90g/L), NaNO"3 (2...
Curcumin, the yellow pigment from the rhizoma of Curcuma longa, is a widely studied phytochemical with a variety of biological activities. The ongoing research and clinical trials have proved that this natural phenolic compound has great and diverse pharmacological potencies. Beside its effective antioxidant, antiinflammatory, and antimicrobial/antiviral properties, curcumin is also considered as a cancer chemopreventive agent. While the antioxidant activity of curcumin is well documented, its interaction with DNA and RNA is not fully investigated. This study was designed to examine the interactions of curcumin with calf thymus DNA and yeast RNA in aqueous solution at physiological conditions, using constant DNA and RNA concentration (6.25?mM) and various curcumin/polynucleotide (phosphate...
Direct plating, selective enrichment, and cold enrichment followed by secondary selective enrichment procedures were compared for detecting and enumerating Listeria monocytogenes in chopped cabbage stored at 5 degrees C for up to 64 days. Addition of Fe3+ to solid media enhanced detection of the organism. Cold enrichment (5 degrees C) in nutrient broth and brain heart infusion broth followed by secondary enrichment (48 h, 30 degrees C) in Trypticase soy-yeast extract-antibiotic broth and thiocyanate-nalidixic acid broth and plating on selective agar media (Doyle and Schoeni selective enrichment agar [minus acriflavin hydrochloride, supplemented with 5 micrograms of Fe3+/ml] and McBride Listeria agar) resulted in the detection of highest populations. PMID:3111369
The potential of the yeast Candida tropicalis and Candida guillermondii was evaluated and an isolated partnership of microorganisms of waters of the Medellin River, conformed by two bacteria and one leavening, to degrade the content of organic matter present in wine produced by the factory of Licores and Alcoholes de Antioquia (FLA) in aerobic process with biomass production. For each one of the microorganisms in study this capacity of removal in units of chemical demand of oxygen was quantified (CDO); in addition, parameters were analyzed such as yield of the biomass in relation to the removed CDO and to total reducing sugars (TRS) consumed, time of fermentation and speed of growth different dilutions from wine. Also the possible inhibition was analyzed that the present phenolic compounds in this wine can cause in the biological process of degradation.
Cellulose sausage cellulose casings are used extensively in the manufacture of sausages in meat packaging. After stripping the meat, spent casings mainly contain cellulose and residual meat juice with salt, nitrate and nitrite. Disposal of spent sausage casings has serious economic and environmental concerns for the sausage industry. This work describes bioconversion of spent cellulose casings (SCC) into enzymes, lactic acid and ethanol by using cellulolytic fungi, lactobacillus and yeasts. The solid substrate cultivation (SSC) of Trichoderma reesei RUT C-30 on SCC and blends gave a maximum of 152 filter paper cellulase (FPase) activity and about 100 carboxymethylcellulase activity (CMCase)/g dry weight substrate. The SSC produced enzyme-rich casing with 50 FPase when directly mixed as suc...
In this work, silver-montmorillonite (Ag-MMT) antimicrobial nanoparticles have been obtained by allowing silver ions from nitrate solutions to replace the Na^+ of natural montmorillonite and then to be reduced by a thermal treatment. Ag-MMT were used as active antimicrobial compounds to improve the shelf life of fresh fruit salad. In order to assess their influence on product shelf life, sensorial and microbiological quality has been monitored during the storage. The microbiological quality was determined by monitoring the principal spoilage microorganisms (mesophilic and psychrotrophic bacteria, coliforms, lactic acid bacteria, yeasts and molds). Additionally, the evolution of sensorial quality was assessed by monitoring color, odor, firmness and product overall quality. The Ag-MMT nanopa...
A number of aerobic species capable of decolorizing some of the dyes in a textile mill effluent were isolated. One of the isolates was able to decolorize Terasil black dye under aerobic conditions in the presence of an exogenous carbon source after 5 days. Glucose or starch (%1 ea) are essential for decolorization but the process proceeds faster in the presence of 0.5% yeast extract. Results of the BOD5 show that the untreated effluent samples have a low BOD value, whereas treated samples show an initial increase in BOD up to 15 days followed by a decrease after 20 days. FT-IR and GC-MS data also reveal that the initial components in the untreated effluent disappear after 20 days of treatment, confirming biodegradation of the dye. Phytotoxicity tests on the untreated effluent samples using...
Beside yeasts, lactic acid bacteria (LAB) are the most abundant microbes in must during vinification. Whereas Oenococcos oeni is commercially used as a starter culture for the biological acid reduction in wines, other species are responsible for different types of wine spoilage. Members of the genera Pediococcus, Weissella, Leuconostoc, and Lactobacillus are producers of exopolysaccharide slimes, biogenic amines, acetic acid, and other off-flavors. In order to control microbial growth, different procedures such as heating of must and addition of sulfite or lysozyme from egg white are generally applied. Yet, because of health risks, the application of sulfite should be reduced and lysozyme is not effective against all LAB. In this study, we describe exoenzymes from a Streptomyces sp. strain...
Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells after irradiation were studied in the long-term culture of mouse bone marrow cells in vitro. No difference was observed in the survival of the stem cells among cultures in which 0 - 10/sup 7/ cells were re-inoculated on the adherent cell colonies in the culture flask. Stem cells showed a significant proliferation within 1 week and the number of the stem cells exceeded the control in 3 weeks after irradiation in the cultures with less than 10/sup 6/ re-inoculated cells per flask. In contrast, there was a considerable delay in the onset of stem cell proliferation after irradiation in the culture with 10/sup 7/ cells per flask. Based on these results, a possibility that a ...
Strong coupled organic-inorganic microcavities device has been realized and studied. One of the two cavities contains an organic thin film of tetrakis(4-methoxyphenyl)porphyrin, whereas the other microcavity is a dielectric structure coupled to the organic one by means of a LiF/ZnS Bragg mirror. Reflectivity spectra show the presence of two well defined cavity dips. We observe an energy splitting of the two cavity-modes. Despite only one cavity contains the active layer, the photoluminescence spectra display two peaks at the same energy of the reflectivity dips. These observations indicate the strong coupling of the two cavities. The comparison of the diagonalized effective Hamiltonian with the observed resonances further confirms the strong coupling.
Possible anomalous top-quark couplings induced by SU(2)xU(1) gauge-invariant dimension-6 effective operators were studied in the process of ttbar productions and decays at polarized {gamma}{gamma} colliders. Two CP-violating asymmetries, a linear-polarization asymmetry and a circular-polarization asymmetry, were computed including both non-standard ttbar{gamma} and {gamma}{gamma}H couplings. An optimal-observable analysis for the process {gamma}{gamma}{yields}ttbar{yields}l{sup {+-}} was performed in order to estimate the precision for determination of all relevant non-standard couplings, including the anomalous tbW coupling.
The celebrated Kuramoto model captures various synchronization phenomena in biological and man-made dynamical systems of coupled oscillators. It is well-known that there exists a critical coupling strength among the oscillators at which a phase transition from incoherency to synchronization occurs. This paper features three contributions. First, we characterize and distinguish the different notions of synchronization used throughout the literature and formally introduce the concept of phase cohesiveness as an analysis tool and performance index for synchronization. Second, we review the vast literature providing necessary, sufficient, implicit, and explicit estimates of the critical coupling strength in the finite and infinite-dimensional case. Finally, we present the first explicit necessary and sufficient condition on the critical coupling strength to achieve synchronization in the finite-dimensional ...
Cockayne syndrome (CS) is a rare autosomal recessive disease, which shows diverse clinical symptoms such as photosensitivity, severe mental retardation and developmental defects. CS cells are hypersensitive to killing by ultraviolet (UV)-irradiation and defective in transcription-coupled repair. Two genetic complementation groups in CS (CS-A and CS-B) have been identified. We analyzed mutations of the CSA gene in 5 CS-A patients and identified 3 types of mutations. Four unrelated CS-A patients (CS2OS, CS2AW, Nps2 and CS2SE) had a deletion including exon 4, suggesting that there is a founder effect on the CSA mutation in Japanese CS-A patients. Patient CS2SE was a compound heterozygote for this deletion and an amino acid substitution at the 106th glutamine to proline (Q106P) in the WD-40 repeat motif of the CSA protein, which resulted in a defective nucleotide excision repair. Patient Mps1 had a large deletion in the upstream region including ...
The response of Desulfovibrio vulgaris Hildenborough (DvH),a sulphate-reducing bacterium, to nitrate stress was examined usingquantitative proteomic analysis. DvH was stressed with 105 m M sodiumnitrate(NaNO3), a level that caused a 50 percent inhibition in growth.The protein profile of stressed cells was compared with that of cellsgrown in the absence of nitrate using the iTRAQ peptide labellingstrategy and tandem liquid chromatography separation coupled with massspectrometry (quadrupoletime-of-flight) detection. A total of 737 uniqueproteins were identified by two or more peptides, representing 22 percentof the total DvH proteome and spanning every functional category. Theresults indicate that this was a mild stress, as proteins involved incentral metabolism and the sulphate reduction pathway were unperturbed.Proteins involved in the nitrate reduction pathway increased. Increasesseen in transport systems for proline, glycine^ ...
The authors have used limited proteolysis of affinity-labeled estrogen receptors (ER), coupled with antireceptor antibody immunoreactivity, to assess structural features of ER and the relatedness of ER from MCF-7 human breast cancer and rat uterine cells. MCF-7 ER preparations covalently labeled with ["3H]tamoxifen aziridine (["3H]TAZ) were treated with trypsin (T), #alpha#-chymotrypsin (C), or Staphylococcus aureus V8 protease prior to electrophoresis on sodium dodecyl sulfate gels. Fluorography revealed a distinctive ladder of ER fragments containing TAZ for each protease generated from the M/sub r/ 66,000 ER. Immunoblot detection with the primate-specific antibody D75P3#gamma# revealed that all immunoreactive fragments corresponded to TAZ-labeled fragments but that some small TAZ-labeled fragments were no longer immunoreactive. In contrast, use of the antibody H222SP#gamma# revealed a correspondence between TAZ-labeled and immunoreactive ...
Wood Plastic Composites (WPCs) have experienced a healthy growth during the last decade. However, improvement in properties is necessary to increase their utility for structural applications. The toughness of WPCs can be improved by creating a fine cellular structure while reducing the density. Extrusion processing is one of the most economical methods for profile formation. For our study, rectangular profiles were extruded using a twin-screw extrusion system with different grades of HDPE and with varying wood fibre and lubricant contents together with maleated polyethylene (MAPE) coupling agent to investigate their effects on WPC processing and mechanical properties. Work has been done to redesign the extrusion system setup to achieve smoother and stronger profiles. A guiding shaper, submerged in the water, has been designed to guide the material directly through water immediately after exiting the die; instead of passing it through a water cooled vacuum ...
Results are presented of molecular dynamics (MD) studies of 1-10 keV displacement cascades in silicon. At these energies, the simulations couple directly to experimental observations of low energy implantation in silicon for shallow junction formation. The simulations are performed with the Stillinger-Weber potential for silicon in computational cells with up to 3.5x10{sup 5} atoms. The author employs periodic boundary conditions in the [100] and [010] directions and a free surface on the top (001) plane. The author discusses the results in terms of the structural evolution and the dynamics of the cascade zones. For sufficiently high energy recoils (>2 KeV), the cascades produce locally molten zones that result in the formation of amorphous silicon pockets upon recrystallization. Frenkel pairs are also produced during the cascade, although their number is very small (less than 10% of the binary collision predictions). Upon annealing of the ...
Simulation and experimental results on the transport of microbes and nutrients in one-dimensional cores are presented, and the development of a three-dimensional, three-phase, multiple-component numerical model to describe the microbial transport and oil recovery in porous media is described. The change of rock's wettability and associated relative permeability values after microbial treatments were accounted for in the model for additional oil recovery. Porosity and permeability reductions due to cell clogging have been considered and the production of gas by microbial metabolism has been incorporated. Governing equations for microbial and nutrient transport are coupled with continuity and flow equations under conditions appropriate for a black oil reservoir. The computer simulator has been used to determine the effects of various transport parameters on microbial transport phenomena. The model can accurately describe the observed ...
Simulation and experimental results on the transport of microbes and nutrients in one-dimensional cores are presented, and the development of a three-dimensional, three-phase, multiple-component numerical model to describe the microbial transport and oil recovery in porous media is described. The change of rock`s wettability and associated relative permeability values after microbial treatments were accounted for in the model for additional oil recovery. Porosity and permeability reductions due to cell clogging have been considered and the production of gas by microbial metabolism has been incorporated. Governing equations for microbial and nutrient transport are coupled with continuity and flow equations under conditions appropriate for a black oil reservoir. The computer simulator has been used to determine the effects of various transport parameters on microbial transport phenomena. The model can accurately describe the observed transport of ...
A home-made 3.1 kWh wind turbine that is promising to be the hottest new wind product to appear for home/farm users in some time, is described. The turbine is installed near a farm house in the high wind area of Mount Forest, Ontario. The turbine is hooked up to a four kilowatt Trace inverter charger which is coupled through a DC disconnect and C-60 charge controller to two sets of solar panels (seven panels of 120 W each by Solarex SX 120, and five panels by Sharp, each providing 1600 watt of solar power). The wind turbine and the solar panels, assisted by two 65-year old refurbished wind turbines, one bank of Gel Cell batteries, and an Onan 5 kW gas generator supply the electrical requirements of a seven member family in a 3400 square foot house. The new turbine is mounted on an 80-foot tower, has three eight foot Kevlar blades that produce a 17 foot overall sweep. The turbine weighs 615 lbs., produces 3.1 kW of pure power at just 310 rpms at ...
SummaryIn vivo tumor cell migration through integrin-dependent pathways is key to the metastatic behavior of malignant cells. Using quantitative in vivo...Full Text Available
Terminal differentiation of many vascular cells involves cell wall changes. Cells first elongate their primary wall, then lay down a lignified secondary wall, which is often followed by digestion of...Full Text Available
Totipotent stem cells have the potential to differentiate into every cell type. Renewal of totipotent stem cells in the germline and cellular differentiation during early embryogenesis rely upon posttranscriptional...Full Text Available
We have established a cartilaginous fish cell line [Squalus acanthias embryo cell line (SAE)], a mesenchymal stem cell line derived from the embryo of an elasmobranch, the spiny dogfish...Full Text Available
AIM: To isolate and identify the biological characteristics of human colon cancer stem cells (SW1116 cells) and further study their proteome.METHODS: SW1116 cells were isolated and cultured with...Full Text Available
Interleukin 2 (IL-2) and B-cell growth factors I and II (BCGF I and BCGF II) are lymphokines produced by T cells that play a major role in T- and B-cell cooperation. Peripheral blood lymphocytes from...Full Text Available
Normal cells, both in vivo and in vitro, become quiescent after serial cell proliferation. During this process, cells can develop immortality with genomic instability,...Full Text Available
BackgroundStem cell characteristics are an important feature of human cancer cells and play a major role in the therapy resistance of tumours. Strategies to target cancer stem cells...Full Text Available
Endothelial cells and mural cells (smooth muscle cells, pericytes, or fibroblasts) are known to communicate with one another. Their interactions not only serve to support fully functional blood...Full Text Available
BackgroundAs the resident stem cells of skeletal muscle, satellite cells are activated by extracellular cues associated with local damage. Once activated, satellite cells will re-enter...Full Text Available
Craniofacial injuries require a variety of different cell types to repopulate areas of bone, cartilage, tendon, and fat. Mesenchymal stem cells (MSCs) provide a multipotent cell source for tissue...Full Text Available
We describe the lethal, recessive accelerated-cell-death11 Arabidopsis mutant (acd11). Cell death in acd11 exhibits characteristics of animal apoptosis...Full Text Available
Somatic cell nuclear transfer or therapeutic cloning has provided great hope for stem cell-based therapies. However therapeutic cloning has been experiencing both ethical and technical difficulties....Full Text Available
Background:Stem cells can differentiate into multiple cell types, and therefore can be used for cellular therapies, including tissue repair. However, the participation of stem cells...Full Text Available
It has been postulated that thrombin binds to endothelial cells through, at least in part, cell surface glycosaminoglycans such as heparan sulfate, which could serve as antithrombin cofactor on the...Full Text Available
Hematopoietic stem cells replenish all the cells of the blood throughout the lifetime of an animal. Although thousands of stem cells reside in the bone marrow, only a few contribute to blood production...Full Text Available
In the growing chloronema cell suspension cultures of the moss Funaria hygrometrica Hedw., activities of several enzymes have been found to be cell-density-dependent. Cyclic nucleotide...Full Text Available
In preimplantation mouse development, the first cell lineages to be established are the trophectoderm (TE) and inner cell mass. TE possesses epithelial features, including apical-basal cell polarity...Full Text Available
...false Guidelines for Human Stem Cell Research Presidential Documents ...2009 Guidelines for Human Stem Cell Research Memorandum for the Heads...scientifically worthy human stem cell research, including human...
We present the complete next-to-leading order (NLO) QCD corrections to the top quark associated with $\\gamma$ production induced by model-independent $tq\\gamma$ and $tqg$ flavor-changing neutral-current (FCNC) couplings at hadron colliders, respectively. We also consider the mixing effects between the $tq\\gamma$ and $tqg$ FCNC couplings for this process. Our results show that, for the $tq\\gamma$ couplings, the NLO QCD corrections can enhance the total cross sections by about 50% and 40% at the Tevatron and LHC, respectively. Including the contributions from the $tq\\gamma$, $tqg$ FCNC couplings and their mixing effects, the NLO QCD corrections can enhance the total cross sections by about 50% for the $tu\\gamma$ and $tug$ FCNC couplings, and by about the 80% for the $tc\\gamma$ and $tcg$ FCNC couplings at the LHC, respectively. Moreover, the NLO corrections ...
We have developed a cell-mediated mutagenesis assay in which cells with the appropriate markers for mutagenesis are co-cultivated with either lethally irradiated rodent embryonic cells that can metabolize carcinogenic hydrocarbons or with primary rat liver cells that can metabolize chemicals carcinogenic to the liver. During co-cultivation, the reactive metabolites of the procarcinogen appear to be transmitted to the mutable cells and induce mutations in them. Assays of this type make it possible to demonstrate a relationship between carcinogenic potency of the chemicals and their ability to induce mutations in mammalian cells. In addition, by simultaneously comparing the frequencies of transformation and mutation induced in normal diploid hamster cells by benzo(a)pyrene (BP) and one of its metabolites, it is possible to estimate the genetic ...
...Basic Information | Fuel Cells & Vehicles | US EPA This web page provides basic information on EPA's Fuel Cells & Vehicles web site ...including the chemical composition of fuel cell technology, how it works, descriptions of the various types of fuel cells , their availability and ... background,electrochemical,hydrogen,fuel cell,fuel cell vehicle,fuel reformer,performace,improved fuel economy,increased engine efficiency,lower emissions,zero emissions,availablity,fuel cell types,diagram,Proton ...Exchange Membrane,PEM Basic Information | Fuel Cells & Vehicles | US EPA background,electrochemical,hydrogen,fuel cell,fuel cell vehicle,fuel reformer,performace,improved fuel economy,...
Laser-assisted processing techniques for producing high-quality solar cell metallization patterns are investigated, developed, and characterized. The tasks comprising these investigations are outlined. A new batch of solar cells was processed using the laser decomposition of spun-on silver neodecanoate to metallize cells. Decomposition of silver neodecanoate was carried out at different laser powers on different cells on a given wafer to determine whether this would have any effect on cell performance. Solar cells which were written with laser powers of 5 to 8 watts, gave excellent results with cell efficiencies in the range of 14 to 16%.
... nent to the design and construction of metal-semiconductor solar cells, in that both the photovoltage and the efficiency of metal-semiconductor cells ...
... and pathogen transmission. Because the ultimate object of stem cell research is cell-based clinical therapy, hES cells should ... 4%) Supported by grants (SC12021 and SC11012) from Stem Cell Research...
Abstract Epstein-Barr virus (EBV), which infects not only B cells, but also T cells and natural killer (NK) cells, is associated with multiple lymphoid malignancies. Recently, the proteasome inhibitor bortezomib was reported to induce apoptosis of EBV-transformed B cells. We evaluated the killing effect of this proteasome inhibitor on EBV-associated T lymphoma cells and NK lymphoma cells. First, we found that bortezomib treatment decreased the viability of multiple T and NK cell lines. No significant difference was observed between EBV-positive and EBV-negative cell lines. The decreased viability in response to bortezomib treatment was abrogated by a pan-caspase inhibitor. The induction of apoptosis was confirmed by flow cytometric assessment of annexin V staining. Additionally, cleavage o...
In order to identify cells of maternal origin in CVS cultures, tissue from 1st trimester abortions were cultivated and the cultures stained in situ for X-chromatin. Convoluted cells and maternal fibroblasts were found to be positive. By chromosome analysis of cultures from 105 diagnostic placenta biopsies, obtained by the transabdominal route, metaphases of maternal origin were found in nine cases. In eight of these cases colonies of convoluted cells were observed. We conclude that convoluted cells are of maternal origin and are a reliable marker for maternal cell contamination in CVS cultures.
Using Zgamma candidate events collected by the CDF detector at the Tevatron Collider, we search for potential anomalous (non-standard-model) couplings between the Z boson and the photon. At the hard scatter energies typical of the Tevatron, standard model Zgamma couplings are too weak to be detected by current experiments; hence any evidence of couplings indicates new physics. Measurements are performed using data corresponding to an integrated luminosity of 4.9 /fb in the Z -> nunubar decay channel and 5.1 /fb in the Z -> l^+l^- (l=mu, e) decay channels. The combination of these measurements provides the most stringent limits to date on Zgamma trilinear gauge couplings. Using an energy scale of Lambda = 1.5 TeV to allow for a direct comparison with previous measurements, we find limits on the CP-conserving parameters that describe Zgamma couplings to be |h_3^{\\gamma,Z}| < ...
An assay system for the stem cell that colonizes the thymus and differentiates into T cells was developed, and by using this assay system the existence of two subpopulations of stem cells for T cell lineage was clarified. Part-body-shielded and 900-R-irradiated C57BL/6 (H-2b, Thy-1.2) recipient mice, which do not require the transfer of pluripotent stem cells for their survival, were transferred with cells from B10 X Thy-1.1 (H-2b, Thy-1.1) donor mice. The reconstitution of the recipient's thymus lymphocytes was accomplished by stem cells in the donor cells and those spared in the shielded portion of the recipient that competitively colonize the thymus. Thus, the stem cell activity of donor cells can be evaluated by determining the proportion of donor-type (Thy-1.1+) ...
Understanding prostate stem cells may provide insight into the origin of prostate cancer. Primary cells have been cultured from human prostate tissue but they usually survive only 15-20 population doublings before undergoing senescence. We report here that RC-170N/h/clone 7 cells, a clonal cell line from hTERT-immortalized primary non-malignant tissue-derived human prostate epithelial cell line (RC170N/h), retain multipotent stem cell properties. The RC-170N/h/clone 7 cells expressed a human embryonic stem cell marker, Oct-4, and potential prostate epithelial stem cell markers, CD133, integrin #alpha#2#beta#1"h"i and CD44. The RC-170N/h/clone 7 cells proliferated in KGM and Dulbecco's Modified Eagle Medium with 10% fetal bovine serum and 5 #mu#g/ml insulin (DMEM + 10% FBS + Ins.) ...
We investigate the effect of anomalous gamma-W-W couplings in e-gamma --> nu W through the angular and energy spectrum of the secondary leptons. Within the narrow-width approximation, a semi-analytical study of the secondary lepton energy-angle double distribution is considered. Utility of observables derived from this is demonstrated by considering the anomalous coupling, delta-kappa-gamma. Results of our investigation for typical ILC machine considered at Ecm = 300-1000 GeV re-affirms potential of this collider as a precision machine.
We have investigated the effect of the rho tensor coupling on binding energies, matter root-mean-square radii and spin orbit splittings of Ca isotopes in the relativistic mean-field theory with sigma, omega, and rho mesons. It is shown that binding energies and matter root-mean-square radii are insensitive to an alteration in the strength of the rho tensor coupling and an explanation of this is given. We have further shown that inclusion of the rho tensor coupling will give isospin-dependent spin-orbit splittings and this will greatly affect spin-orbit splittings of nuclei near the neutron drip line. (author). Letter-to-the-editor.
A process for the production of transportation fuels from heavy hydrocarbonaceous feedstock is provided comprising a two-stage, close-coupled process, wherein the first stage comprises a hydrothermal zone into which is introduced a mixture comprising a feedstock and red mud having coke-suppressing and demetalizing activity, and hydrogen; and the second, close-coupled stage comprises a hydrocatalytic zone into which substantially all the effluent from the first stage is directly passed and processed under hydrocracking conditions.
A process for the production of transportation fuels from heavy hydrocarbonaceous feedstock is provided comprising a two-stage, close-coupled process, wherein the first stage comprises a hydrothermal zone into which is introduced a mixture comprising a feedstock and metals-impregnated red mud having coke-suppressing and demetalizing activity, and hydrogen; and the second, close-coupled stage comprises a hydrocatalytic zone into which substantially all the effluent from the first stage is directly passed and processed under hydrocatalytic conditions. The preferred metals for impregnation include transition metals, in particular, nickel and molybdenum.
The problem of thermal instability of compressible, electrically conducting couple-stress fluids in the presence of a uniform magnetic field is considered. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection, the compressibility, couple-stress, and magnetic field postpone the onset of convection. Graphs have been plotted by giving numerical values of the parameters to depict the stability characteristics. The principle of exchange of stabilities is found to be satisfied. The magnetic field introduces oscillatory modes in the system that were non-existent in its absence. The case of overstability is also studied wherein a sufficient condition for the non-existence of overstability is obtained. (orig.)
This executive summary presents the motivation, structure, objectives, methodologies and results of the first stage of the international DECOVALEX project - DECOVALEX I (1992-1995). The acronym stands for Development of Coupled Models and their Validation against Experiment in Nuclear Waste Isolation, and the project is an international effort to develop mathematical models, numerical methods and computer codes for coupled thermo-hydro-mechanical processes in fractured rocks and buffer materials for geological isolation of spent nuclear fuel and other radioactive wastes, and validate them against laboratory and field experiments. 24 refs.
The effect of the electric field on an exciton confined in a pair of vertically coupled quantum dots is studied. We use a single-band approximation and a parabolic model potential. As a result of these idealizations, we obtain a numerically solvable model, which is used to describe the influence of the electron-hole interaction on the Stark effect for the lowest-energy photoluminescence lines. We show that for intermediate tunnel coupling between the dots this interaction leads to an anomalous Stark effect with an essential deviation of the recombination energy from the usual quadratic dependence on the electric field.
Close coupled expressions for phenomenological cross sections which describe transport properties of atom--diatom mixtures are obtained in the total-J coupling scheme and are related to the bracket integrals of kinetic theory. Coupled states and infinite order sudden expressions for the generalized phenomenological cross sections using initial, final, and average l-labeling are also given. Particular care is taken to use a phase convention for the CS and IOS approximations which is consistent with the Arthurs--Dalgarno formalism and which gives the correct behavior of degeneracy averaged differential cross sections.
The double diffusive convection in a horizontal couple stress fluid saturated anisotropic porous layer, which is heated and salted from below, is studied analytically. The modified Darcy equation that includes the time derivative term is used to model the momentum equation. The critical Rayleigh number, wavenumber for stationary and oscillatory modes, and frequency of oscillations are obtained analytically using linear theory. The effect of anisotropy parameter, solute Rayleigh number, Lewis number, couple stress parameter, and Vadasz number on the stationary, oscillatory, and finite amplitude convection is shown graphically. It is found that the thermal anisotropy parameter, couple stress parameter, and solute Rayleigh number have stabilizing effect on the stationary, oscillatory, and fin...
The immediate early gene Arc is emerging as a versatile, finely tuned system capable of coupling changes in neuronal activity patterns to synaptic plasticity, thereby optimizing information...Full Text Available
Reflectometric methods like polarised neutron reflectometry (PNR) and synchrotron Moessbauer reflectometry (SMR) are capable of investigating the plane-perpendicular and lateral magnetic structure of multilayers (MLs). Previously, a variety of domain formation and transformation phenomena was found and systematically studied in a Fe/Cr ML of strong antiferromagnetic coupling by PNR and SMR. Growth of the primary domains on passing the bulk-spin-flop transition was established. The domains were found to revert to their native state only in a field considerably higher than the apparent saturation field, a phenomenon referred to as the supersaturation domain memory effect (SDME). We present a comparative PNR study of two antiferromagnetically coupled Fe/Cr MLs with different magnetisation curves. We show that the distribution of the layer-layer coupling rather than the magnetic structure of the Cr spacer layer is responsible ...
For coupled quantum wires and dots, tunneling effects and coherent transport for quantum computing are being studied. In 2D systems, electron-hole bilayers for exciton...
BACKGROUNDThe reproductive health of children born of infertile couples may be affected by infertility treatment or factors associated with infertility. We examined sexual maturation...Full Text Available
Orphan G protein-coupled receptors (GPCRs) are receptors lacking endogenous ligands. Found by molecular biological analyses, they became the roots of reverse pharmacology, in which receptors are attempted...Full Text Available
NEWTON's first law prohibits the coupling of free tachyons to ordinary matter, if it is interpreted as selection rule interdicting emission without change of the rest-mass of the emitting system.
coupled heat/mass transfer Stefan problem. Taking the diffusion coefficient of Bi as a free parameter, the best fit was observed for the published value, ...
This paper is concerned with the study of the Electrorheological RayleighTaylor instability (ERTI) at the interface between a densely packed saturated poorly conducting couple stress porous layer accelerated by a lighter poorly conducting couple stress fluid in a thin shell in the presence of a transverse electric field and laser radiation. A simple theory based on fully developed flow approximations is used to derive the dispersion relation for the growth rate of ERTI. The cutoff and the maximum wave numbers and the corresponding maximum frequencies are obtained. It is shown that the effects of couple stress parameter and the electric field reduce the growth rate considerably compared to a non-conducting fluid in the absence of an electric field. These are favorable to control the surface...
As a general approach to the problem of precursive behavior in alloys that undergo a displacive transformation, defect theories are becoming increasingly popular. However, the microscopic origin of the proposed defects is usually not considered. Yu and Anderson (1984) have argued that properties of strong-coupling superconductors, such as the A-15 compounds, imply a breakdown of Migdal's theorem (the adiabatic, or Born-Oppenheimer approximation for separation of electrons and phonons) in these systems. The electron-phonon coupling is so strong that it must be incorporated already in zeroth order. This is the basis for local phonon models, in which the electron-phonon coupling provides an effective double well potential for a localized group of atoms. The Yu-Anderson model and an analogous local Jahn-Teller model (Abell, 1983) are reviewed in connection with displacive transformations in ...
Code coupling activities have so far focused on coupling the neutronics modules with the CFD module. An interface module for the CFD-ACE/DeCART coupling was established as an alternative to the original STAR-CD/DeCART interface. The interface module for DeCART/CFD-ACE was validated by single-pin model. The optimized CFD mesh was decided through the calculation of multi-pin model. It was important to consider turbulent mixing of subchannels for calculation of fuel temperature. For the parallel calculation, the optimized decompose process was necessary to reduce the calculation costs and setting of the iteration and convergence criterion for each code was important, too.
This study performs a dynamic analysis of the rub-impact rotor supported by two couple stress fluid film journal bearings. The strong nonlinear couple stress fluid film force, nonlinear rub-impact force and nonlinear suspension (hard spring) are presented and coupled together in this study. The displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The numerical results show that the dynamic behaviors of the system vary with the dimensionless speed ratios, the dimensionless unbalance parameters and the dimensionless parameter, l*. Inclusive of the periodic, sub-harmonic, quasi-periodic and chaotic motions are found in this analysis. The results of this study contribute to a further understanding of the nonlinear dynamics of a rotor-...
Using a realistic three-body model, angular distributions for the "1"6O(d,p)"1"7O(1/2"+) reaction, based on the channel coupling array (CCA) theory and various forms of the coupled reaction channel (CRC) method are compared. Despite the different forms and theoretical foundations of these methods, they yield similar angular distributions, within the bound state approximations used herein. The expected breaking of time reversal inveriance in the approximated CCA theory is quite small over most of the angular range. Of all the methods used, coupling effects in the forward directions are largest for the post form of the CRC, indicating that it is the least reliable of the CRC forms for fitting data. (Auth.).
AbstractWe propose a mechanism for the formation of membrane oscillations and traveling waves, which arise due to the coupling between the actin cytoskeleton and the calcium flux through...Full Text Available
This chapter consists of some points including an introduction, the basic parts of mass spectroscope device, sample introduction into the inductively coupled plasma, pneumatic nebuliser, ultrasonic nebuliser, dry gas cloud system, laser ablation unit, inductively coupled plasma-ion source, extraction of ions from ion source, mass analysis, quad-polar mass spectrometer, dual assembly mass spectrometer, mass spectrometer by calculation of time of flight, ion interferences and the ability of resolution, ion counter, working conditions of inductively coupled plasma mass spectroscope device, efficiency of ion transportation in an inductively coupled plasma mass spectroscope device and applications of analysis using mass spectroscope of induced plasma including nuclear, industrial, geological, environmental and archaeological applications, measurement of isotopes ratio and applications in tracing crimes.
Concerning the requirements of future rocket technologies, providing a cost-efficient access to orbit as well as an increase in system reliability, a deeper insight into the unsteady phenomena during ascent of modern launchers is essential. Unsteady interactions and resonances of the turbulent separated launcher wake and the nozzle structure play an important role for the design of future main stage propulsion systems. The so-called buffeting coupling phenomenon is one of the main challenges during ascent. In the present study, a coupled simulation of the afterbody of the Ariane-5 launcher with a realistic structural and aerodynamic representation of different nozzle configurations is carried out. On the computational fluid dynamics side, unsteady detached eddy simulations are coupled with...
The herbicide atrazine is a known immunotoxicant and an inhibitor of human natural killer (NK) cell lytic function. The precise changes in NK cell lytic function following atrazine exposure have not been fully elucidated. The current study identifies the point at which atrazine exerts its affect on the stepwise process of human NK cell-mediated lyses of the K562 target cell line. Using intracellular staining of human peripheral blood lymphocytes, it was determined that a 24-h in vitro exposure to atrazine did not decrease the level of NK cell lytic proteins granzyme A, granzyme B or perforin. Thus, it was hypothesized that atrazine exposure was inhibiting the ability of the NK cells to bind to the target cell and subsequently inhibit the release of lytic protein from the NK cell. To test t...
Introduction: Haploidentical transplantation, with extensive T cell depletion to prevent GvHD, is associated with a high incidence of infection-related deaths. The key challenge is to improve immune recovery with allogeneic donor T cells without triggering GvHD. As T regulatory cells (Tregs) controlled GvHD in pre-clinical studies, the present study evaluated the impact of an infusion of donor CD4/CD25 + Tregs, followed by an inoculum of donor mature T cells (Tcons) and positively immunoselected CD34 + cells in the setting of haploidentical stem cell transplantation. Patients and methods: Twenty-eight patients were enrolled in this study (22 AML; 5 ALL; 1 NHL). All received immunoselected Tregs (CliniMACS, Miltenyi Biotec) followed by positively immunoselected CD34 + cells together with Tc...
This thesis deals with the analysis of dominant loss mechanisms in direct methanol fuel cells (DMFC) and hydrogen fed polymer electrolyte membrane fuel cells (PEFC) by means of experimental characterization and modeling work. Due to different fuels used in these two fuel cell types, the dominant loss mechanisms are different in their nature. All in-situ characterization techniques that are used in this work are based on a novel test fuel cell with embedded reference electrodes. The first part of this work presents a new concept for realizing a reference electrode configuration in a polymer electrolyte membrane fuel cell by means of laser ablation. The laser beam is used to evaporate a small gap into the electrode surface of a catalyst coated membrane (CCM) to isolate the reference electrode from the working/counter electrode (WE/CE). This method enables the simultaneous ablation of ...
The presence of a high number of activated T cells in the bloodstream and spontaneous proliferation of peripheral blood mononuclear cells in vitro are striking characteristics of human T-cell leukemia...Full Text Available
The article is the second part of a review dealing with latest developments in the area of solar cell technologies and application. Physical principles, design and efficiency as well as advantages and disadvantages of GaAs- and CdS-solar cells are described. Power generation solar cell systems with voltage converters, combined solar cell/solar collector systems and thermoelectric solar systems are presented in the second part of the article.
The herbicide atrazine is a known immunotoxicant and an inhibitor of human natural killer (NK) cell lytic function. The precise changes in NK cell lytic function following atrazine exposure have not been fully elucidated. The current study identifies the point at which atrazine exerts its affect on the stepwise process of human NK cell-mediated lyses of the K562 target cell line. Using intracellular staining of human peripheral blood lymphocytes, it was determined that a 24-h in vitro exposure to atrazine did not decrease the level of NK cell lytic proteins granzyme A, granzyme B or perforin. Thus, it was hypothesized that atrazine exposure was inhibiting the ability of the NK cells to bind to the target cell and subsequently inhibit the release of lytic protein from the NK cell. To test this hypothesis, flow cytometry ...
Cell therapy is a promising novel option for treatment of cardiovascular disease. Because the role of bone marrow-derived circulating progenitor cells (BM-CPCs) after cell therapy is less clear, we...Full Text Available
PCD (programmed cell death) in plants presents important morphological and biochemical differences compared with apoptosis in animal cells. This raises the question of whether PCD arose independently...Full Text Available
Although human T-cell lymphotropic virus type I (HTLV-I) is the etiologic agent of adult T-cell leukemia/lymphoma (ATL), the role of viral gene expression in the progression to and maintenance of the...Full Text Available
Bovine leukemia virus (BLV), a retrovirus related to human T-cell leukemia virus types 1 and 2, can induce persistent nonneoplastic expansion of the CD5+ B-cell population, termed...Full Text Available
Solid Oxide Fuel Cell (SOFC) is expected as a new power generation source. The development of SOFC is being conducted by CRIEPI, and so far several reports of the reults were presented. This report examines materials of SOFC. For the purpose, cells were made using some of typical materials and manufacturing processes, and cell performance tests were carried out.
This study reports on the physical-chemical behaviour of swelling di-octahedral clays (smectites) and their interaction with aqueous solutions and bacteria (Shewanella putrefaciens). Experimental results are presented for compacted clays, hydrated under confined volume conditions, using a new type of reaction-cell (the 'wet-cell' of Warr and Hoffman, 2004) that was designed for in situ X-ray diffraction (XRD) measurement. For comparison, dispersed clay systems were studied using standard batch solutions subjected to varying degrees of agitation. The combination of time-dependent in situ XRD measurements with gravimetric measurements and calculated diffraction patterns using the CALCMIX software (Plancon and Drits, 1999) allowed to successful quantification of the dynamics of water uptake and storage. This analytical procedure combined with published water vapour adsorption data enabled determination of the abundance of ...
The PVSCAN is an instrument designed to characterize silicon solar cell materials and devices. It performs a host of measurements that yield spatial maps of dislocation density, grain distribution, reflectance, and photoresponses from near-junction and the bulk of a solar cell.
The penetration by moxifloxacin of human neutrophils (polymorphonuclear leukocytes [PMN]) and tissue-cultured epithelial cells (McCoy cells) was evaluated by a fluorometric assay. At...Full Text Available
There is ample evidence suggesting that superantigens may act as a triggering factor in the pathogenesis of rheumatoid arthritis (RA). We investigated whether superantigen could activate T cells in...Full Text Available
SUMMARYThe cytolytic activity of natural killer (NK) cells is regulated by inhibitory receptors that detect the absence of self molecules on target cells. Structural studies of...Full Text Available
The proliferation of stem cell research, conflated with its ethical and moral implications, has led governments to attempt regulation of both the science and funding of stem cells. Due to a diversity...Full Text Available
Embryonic stem cells have the ability to develop into virtually any cell in the body, and may have the potential to treat medical conditions such as diabetes and Parkinsons disease. On August 9, 2001, President Bush announced that for the first time feder...
Background: In North America and Europe, 80% of invasive skin cancers are basal cell carcinoma while 20% are squamous cell carcinoma (SCC). In contrast, African studies reveal a preponderance...Full Text Available
BackgroundSpindle cell carcinoma (SpCC) is a rare microscopic type of cancer of the mouth and oropharynx. Although SpCC is thought to arise from squamous cell carcinoma (SCC), it...Full Text Available
This paper describes a radiation shield verification survey of a large hot cell at the Fast Flux Test Facility (FFTF). The following aspects of the shield test are discussed: description of the FFTF; description of the hot cell; the test procedures; radiation protection, and the test results.
... from Dr. Austin Smith of the Institute for Stem Cell Research, University of Edinburgh) was modified from the CGR8 ... to thank Dr. Austin Smith, the Institute for Stem Cell Research, University of Edinbu...
Human myeloid-lineage cells are refractory to HIV-1 infection. The Vpx proteins from HIV-2 and sooty mangabey SIV render these cells permissive to HIV-1 infection through proteasomal degradation of...Full Text Available
Most genetic changes that promote tumorigenesis involve dysregulation of G1 cell cycle progression. A key regulatory site in G1 is a growth factor–dependent restriction point (R) where cells...Full Text Available
Target of rapamycin (TOR) kinases control cell growth through two functionally distinct multiprotein complexes. TOR complex 1 (TORC1) controls temporal cell growth and is sensitive to rapamycin, whereas...Full Text Available
... based, disease treatment remains promising, the emphasis for stem cell research from the biomedical research community is clear, and ... diagnosis as a novel source of embryos for stem cell research. Repr...
The cells of the endosperm of castor bean seeds (Ricinus communis) undergo programmed cell death during germination, after their oil and protein reserves have been mobilized. Nuclear...Full Text Available
Placental and placental-like alkaline phosphatase (PLAP) levels in the culture media of 87 cell lines of neoplastic and 'normal' origin were measured by a conventional immunosorbent enzymatic assay...Full Text Available
The rate and capacity for chloroform (CF) and trichloroethylene (TCE) transformation by a mixed methanotrophic culture of resting cells (no exogenous energy source) and formate-fed cells were measured....Full Text Available
A new method is described for continuously measuring cell turgor pressure (P), hydraulic conductivity (Lp), and volumetric elastic modulus (ε) in higher plant cells, using a pressure...Full Text Available
PURPOSE: To determine the frequency of ophthalmic abnormalities in patients with cutaneous T-cell lymphoma (mycosis fungoides and Sézary syndrome) and T-cell lymphoma involving the skin and...Full Text Available
Neutral endopeptidase 24.11 (NEP, CD10) is a cell-surface enzyme expressed by prostatic epithelial cells that cleaves and inactivates neuropeptides implicated in the growth of androgen-independent prostate...Full Text Available
The primary aim of this study was to develop a model system that uses epidermal cells (keratinocytes and accessory pigmented cells) cultured on a reconstituted basement membrane biomatrix for use in...Full Text Available
Amorphous silicon solar cells have been shown to have efficiencies which degrade as a result of long exposure to light. Annealing such cells in air at a temperature of about 200.degree. C. for at least 30 minutes restores their efficiency.
Special red cells were found on the adaxial surface of tertiary pulvini of Mimosa pudica and experiments performed to determine the origin and function of these cells. Using anatomical...Full Text Available
Red cell transfusions are associated with the development of acute lung injury in the critically ill. Recent evidence suggests that storage induced alterations of the red blood cell (RBC) collectively...Full Text Available
Adhesion of Spirogyra (tentatively, Spirogyra fluviatilis) cells to glass is described. The cells of an algal filament can adhere to a substrate only when they are...Full Text Available
Many patients who undergo hematopoietic cell transplantation (HCT) present with anemia and have received red blood cell transfusions before HCT. As a result, iron overload is frequent and appears...Full Text Available
Understanding the interactions between herpesviruses and their host cells and also the interactions between neoplastically transformed cells and the host immune system is fundamental to understanding...Full Text Available
Stem cells of the human prostate gland have not yet been identified utilizing a structural biomarker. We have discovered a new prostatic epithelial cell phenotype-expressing cytokeratin 6a (Ck6a+...Full Text Available
BackgroundStem cells divide to reproduce themselves and produce differentiated progeny. A fundamental problem in human biology has been the inability to measure how often stem cells...Full Text Available
... is known as "reproductive cloning." The Link to Stem Cell Research Stem cell research and research cloning are closely linked. Scientists in ... to arrive at a position on cloning and stem cell research. Many nations, including the UK, China, and South ...
Although most self-reactive T cells are eliminated in the thymus, mechanisms to inactivate or control T cells specific for extrathymic antigens are required and exist in the periphery. By investigating...Full Text Available
The glycolipid content of human non-seminomatous germ cell tumour cell lines correlates with their differentiation lineage. To analyse whether this reflects the situation in primary tumours, we studied...Full Text Available
One of the major decisions that germ cells make during their development is whether to differentiate into oocytes or sperm. In mice, the germ cells’ decision to develop as male or female depends...Full Text Available
DNA from the peripheral blood mononuclear cells of 17 different individuals infected with human T-cell lymphoma/leukemia virus type II (HTLV-II) was successfully amplified by the polymerase chain reaction...Full Text Available
It Peripheral blood progenitor enriched CD34+ cells (PBPC) are rather often used as stem cell background in cancer patients following high dose therapy. Keeping in mind that precursor dendritic cells (DCs) originate from haematopoietic progenitor cells, purified CD34+ cells might also serve as starting cells for ex-vivo production of DC. The aim of the present study is to develop a clinical grade procedure for ex-vivo production of DC derived from enriched CD34+ cells. Various concentrations of CD34+ cells were grown in gas-permeable Teflon bags with different serum-free and serum-containing media supplemented with GM-CSF, IL-4, TNF-a, SCF, Flt-3L and INF-a. Serum-free CellGroSCGM medium for 7 days followed by CellGroDC medium in 7 days gave equal results as serum-containing ...
Metastatic testicular germ cell tumours are cured in approximately 85% of patients using cisplatin-based combination chemotherapy. Patients who fail to respond have a poor prognosis, and there is a...Full Text Available
The first cell lineage specification in mouse embryo development is the formation of trophectoderm (TE) and inner cell mass (ICM) of the blastocyst. This article is to review and discuss the...Full Text Available
Zygotes of fucoid algae have long been studied as a paradigm for cell polarity. Polarity is established early in the first cell cycle and is then expressed as localized growth and invariant cell division....Full Text Available
Naturally occurring and contaminant ferromagnetic and ferrimagnetic particles have been found within or near cells, and might allow pulsed magnetic fields to create transient cell membrane opening ("pores")....Full Text Available
BackgroundClara cell protein (CC16), the main secretory product of bronchiolar Clara cells, plays an important protective role in the respiratory tract against oxidative stress and...Full Text Available
... ions. MATERIALS AND METHODS Cell Culture Culture of NT2/D1 cells was carried out as described previously (18, 19). NT2 cells were plated at a density of 2. ... ...
BackgroundPerfluorocarbons (PFC) are used to improve gas exchange in diseased lungs. PFC have been shown to affect various cell types. Thus, effects on alveolar type II (ATII) cells...Full Text Available
1. Paired or single recordings of paraventricular and/or supraoptic oxytocin cells at the beginning of suckling in urethane-anaesthetized rats enabled us to study cell recruitment and compare the characteristics...Full Text Available
Reaggregated cells from 6- to 8-day-old mouse cerebella have been used to raise antibodies in rabbits. The interaction of these antibodies with cerebellar cell surface components was assessed by cytotoxicity...Full Text Available
Cells have an internal compass that enables them to move along shallow chemical gradients. As amoeboid cells migrate, signaling events such as Ras and PI3K activation occur spontaneously on pseudopodia....Full Text Available
The cell types involved in the cellular immune response were studied with the GVH in vitro as a test system. Comparison of the activities of cells of different lymphoid organs in the...Full Text Available
Species differences in lifespan have been attributed to cellular survival during various stressors, designated here as ‘cell resilience’. In primary fibroblast cultures, cell...Full Text Available
Stem cell therapies for neurodegenerative disorders require accurate delivery of the transplanted cells to the sites of damage. Numerous studies have established that fluid injections to the hippocampus...Full Text Available
We review the application of C. elegans as a model system to understand key aspects of stem cell biology. The only bona fide stem cells in C. elegans...Full Text Available
One of the main obstacles encountered when trying to culture human seminoma (SE) cells in vitro is massive degeneration of the tumour cells. We investigated whether dissociation of tumour tissue, to...Full Text Available
SummaryFor mammalian somatic cells the importance of microtubule cytoskeleton integrity in interphase cell cycle progression is uncertain. The loss, diminishment, or stabilization...Full Text Available
BACKGROUND--Interstitial lung diseases are characterised by the recruitment of mononuclear cells to disease sites where maturation occurs and activation products, including lysozyme (LZM), are released....Full Text Available
BackgroundA fundamental requirement for the exploitation of embryonic stem (ES) cells in regenerative medicine is the ability to reproducibly derive sufficient numbers of cells of...Full Text Available
Cultured mouse or human embryonic stem (ES) cells provide access to all of the genes required to elaborate the fundamental components and physiological systems of a mammalian cell. Chemical or insertional...Full Text Available
ObjectiveThe goal of the study was to investigate the genetic and molecular basis of a novel syndrome of marked hyperglucagonemia and pancreatic α cell hyperplasia...Full Text Available
Fate maps are generated by marking and tracking cells in vivo to determine how progenitors contribute to specific structures and cell types in developing and adult tissue. An advance in this...Full Text Available
A series of 2-alkylthiopyrine-4-carbothioamides were synthesized, and their anti-fungal potency was tested. The chemical structures were proved by infrared spectroscopy (IR) and {sup 1}H nuclear magnetic resonance ({sup 1}H-NMR) data and by elemental analysis. The minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) assessment were used for the estimation of potential activity in vitro. The study comprising 21 clinical isolates of fungi showed that two compounds exhibited fair inhibitory activity against some yeasts and dermatophytes. Selective fungistatic activity against non-dermatophytes (MIC = 3.12-25.0 {mu}g/mL) was found also in another compound. None of the above compounds showed inhibitory activity against non-dermatophyte filamentous fungi. Microbiological activity of 2-alkylthiopyridine-4-carbothioamides appears to be mainly related to hydrophobicity of alkyl in position 2. (authors). 10 refs., 8 tabs.
Transcriptional regulation of the galactose-metabolizing genes in Saccharomyces cerevisiae depends on three core proteins: Gal4p, the transcriptional activator that binds to upstream activating DNA sequences (UASGAL); Gal80p, a repressor that binds to the carboxyl terminus of Gal4p and inhibits transcription; and Gal3p, a cytoplasmic transducer that, upon binding galactose and adenosine 5'-triphosphate, relieves Gal80p repression. The current model of induction relies on Gal3p sequestering Gal80p in the cytoplasm. However, the rapid induction of this system implies that there is a missing factor. Our structure of Gal80p in complex with a peptide from the carboxyl-terminal activation domain of Gal4p reveals the existence of a dinucleotide that mediates the interaction between the two. Biochemical and in vivo experiments suggests that nicotinamide adenine dinucleotide phosphate (NADP) plays a key role in the initial induction event.
Escherichia coli B and K-12 are equally susceptible to the bacteriostatic effects of aerobic paraquat, but they differed strikingly when the lethality of paraquat was evaluated. E. coli B suffered an apparent loss of viability when briefly exposed to paraquat, whereas E. coli K-12 did not. This difference depended on the ability of the B-strain, but not the K-12 strain, to retain internalized paraquat; the B strain was killed on aerobic tryptic soy-yeast extract plates during the incubation which preceded the counting of colonies. This difference in retention of paraquat between strains was demonstrated by delayed loss of viability, by growth inhibition, and by cyanide-resistant respiration after brief exposure to paraquat, washing, and testing in fresh medium. This difference was also shown by using ({sup 14}C)paraquat. This previously unrecognized difference between E. coli B and K-12 has been the cause of apparently contradictory reports and should lead to some ...
The authors describe a cloning strategy for the construction of a human genomic library in yeast artificial chromosomes (YACs) based on complete digestion of high-molecular-weight DNA with the infrequently cutting restriction enzyme MluI. Cloning of MluI fragments in the vector pYAC-RC and one subsequent size fractionation by preparative pulsed-field gel electrophoresis yielded a library with average insert sizes of 600 kb. Ninety-seven percent of the colonies were recombinant. An additional size fractionation of MluI fragments prior to ligation had no significant influence on the size of the YACs. The library currently consists of 5000 clones, which is the equivalent of one human genome. Nineteen percent of the YACs were larger than 1.2 Mb. Since smaller MluI fragments are lost during sizing, they also performed cloning without size fractionation. Only 20% of the colonies were recombinant, probably due to unligated vector fragments that were present during the ...
The potential of the dried yeast, wild-type Schizosaccharomyces pombe, to remove Ni(II) ion was investigated in batch mode under varying experimental conditions including pH, temperature, initial metal ion concentration and biosorbent dose. Optimum pH for biosorption was determined as 5.0. The highest equilibrium uptake of Ni(II) on S. pombe, q e, was obtained at 25??C as 33.8?mg?g?1. It decreased with increasing temperature within a range of 25?50??C denoting an exothermic behaviour. Increasing initial Ni(II) concentration up to 400?mg?L?1 also elevated equilibrium uptake. No more adsorption took place beyond 400?mg?L?1. Equilibrium data fitted better to Langmuir model rather than Freundlich model. Sips, Redlich?Peterson, and Kahn isotherm equations modelled the investigated system with a...
This presentation describes a method for separating {sup 14}C-hexose from {sup 14}C-sucrose in extracts of plant tissue. Portions of ethanol extracts are treated with activated charcoal in microcentrifuge tubes. Aliquots are removed, ethanol evaporated and replaced with reaction mixture that phosphorylates hexose (HEPPS, K{sub 2}HPO{sub 4}, Mg(C{sub 2}H{sub 3}O{sub 2}){sub 2}, ovalbumen, Na{sub 2}ATP, yeast hexokinase). After a time course, the hexokinase reaction is stopped (slowed considerably) to minimize effects of contamination enzyme activities. The stopping agent used is lyxose, a nonphosphorylable analogue of glucose. The strong anionic charge of phosphate introduced through the hexokinase action results in binding (> 95%) of hexose-phosphate to anion-exchange resin. Sucrose remains unbound (> 95%) in solution. This batch ion-exchange is performed in microcentrifuge tubes to allow many samples to be processed simultaneously. Recovery of radiolabel in ...
It may result in acute radiation syndrome after body is exposed to ionizing radiation. The one of long-term effects of irradiation injury is leukemia. The bone marrow cells (BMC) transplantation including stem cells is the only effective therapy for acute radiation syndrome patients. Recently, with the advancement of stem cell research that the stem cells have multipotential and can convert each other, it may supply the new stem source for the irradiation injury patients. At the same time with the further research of radioprotective reagents, the hematopoietic stem cells proliferation after irradiation injury is promoted
In the last two years, rapid progress has been made in the energy conversion efficiencies of GaAs solar cells fabricated from molecular beam epitaxy (MBE) material. The efficiencies of cells fabricated from MBE material are now comparable with those fabricated from metal-organic chemical vapor deposition material, even for cells of dimension 2 cmx4 cm. This paper reviews the progress in MBE cell efficiencies. Also discussed is the role oval defects play in GaAs diode and solar cell performance. (orig.).
As concern regarding global environmental problems such as the greenhouse effect and acid rain has increased, so too has the demand for commercially viable solar cells as a clean energy source. Interest in amorphous silicon (a-Si) solar cells has been particularly high, due to their low cost. Technological developments in the field of a-Si solar cells are discussed from the viewpoints of fabrication process, materials, and cell structures. Various applications and systems that take advantage of the a-Si solar cell are then introduced. Finally, future prospects are mentioned
Transdifferentiation of an individual's own cells into functional differentiated cells to replace an organ's lost function would be a personalized approach to therapeutics. In this two part series, we will describe the progress toward establishing functional transdifferentiated adrenal cortical cells. In this article (Part 2), we describe the disorders of the adrenal cortex, therefore establishing why there is the need for personalized cell-based therapy for individuals with these disorders. We then present our pilot studies of cell transdifferentiation toward an adrenal cortical fate using genes described in the first article of this pair (Part 1).
In this contract, Laser-assisted processing techniques for producing high-quality solar cell metallization patterns are being investigated, developed, and characterized. The tasks comprising these investigations are outlined. Four new batches of solar cells were processed, in addition to several test runs on wafers, using the laser decomposition of spun-on silver neodecanoate to metallize cells. Decomposition of silver neodecanoate was carried out at different laser powers on different cells on a given wafer to determine whether this would have any effect on cell performance. A one watt laser power gave an electroplated linewidth of 50 microns , while at 8 watts the line width was 90 microns.
We report on multijunction GaInP/GaAs photovoltaic cells with total-area efficiencies of 29.5% at one-sun concentration and air mass (AM) 1.5 global and 25.7% one-sun, AM0. These values represent the highest efficiencies achieved by any solar cell under these illumination conditions. Three key areas in this technology are identified and discussed: the grid design, front surface passivation of the top cell, and bottom surface passivation of both cells. Aspects of cell design related to its operation under different solar spectra and under concentration are also discussed.
The theory for the general case of solar cells operating inside integrating cavity receivers is established. This is applied to the particular case of different configurations of silicon and GaAs cells. The results of the analysis show that a composite system of silicon and GaAs cells manufactured using relatively simple technology could reach an efficiency of 34%. The optimal configuration is that in which the GaAs cells are placed in the directly illuminated area of the receiver and the silicon cells are placed in the indirectly illuminated area of the receiver. (orig.).
Numerical results on aeroelastic standard configurations are presented. The methods used for two dimensional configurations include the small perturbations approach for inviscid flow, coupling methods for unseparated flow, coupling methods for unseparated or separated, laminar or turbulent boundary layers, and a numerical solution of the Euler equations for inviscid flow. The three dimensional configurations are studied by the transonic small disturbance approach. The detailed results are given.
The electron-phonon coupling constant lambda has been calculated for vanadium. The electron energy bands and wave functions were obtained from a model augmented plane wave muffin-tin potential. The electron-phonon matrix elements were evaluated using the rigid-ion approximation and the measured phonon spectra. The results show that lambda is strongly affected by d-f scattering.
A method to deduce the 2 x 2 transport matrix for coupled heat and particle transport in Tokamaks is proposed. The method applies to perturbative experiments, and is based on a Fourier transform of the measured signals of temperature and density. By analyzing different linear combinations of temperature and density, the eigenvectors and eigenvalues of the transport matrix are determined. The method is tested for a number of illustrative cases using simulated data, and the sensitivity to noise on the signals is evaluated. (author).
To simulate the effects of the breakup channel on rearrangement amplitudes, the conventional coupled-reaction-channel (CRC) expansion is augmented by pseudoreaction channels. The construction of the projector for the extended CRC space is discussed, and transition-operator equations on this space are given. By solving the full and post-approximation forms of the CRC equations for a model three-particle problem, the crucial role played by the nonorthogonality terms is demonstrated.
To simulate the effects of the breakup channel on rearrangement amplitudes, the conventional coupled-reaction-channel (CRC) expansion is augmented by pseudoreaction channels. The construction of the projector for the extended CRC space is discussed, and transition-operator equations on this space are given. By solving the full and post-approximation forms of the CRC equations for a model three-particle problem, the crucial role played by the nonorthogonality terms is demonstrated.
A general palladium-catalyzed carbonylative Sonogashira coupling of benzyl chlorides with terminal acetylenes has been established. Depending on the alkyne 1,4-diaryl-3-butyn-2-ones or substituted furanones are obtained in moderate to good yields. Best catalytic performance is achieved applying a mixed Pd(PPh(3))Cl(2)/P(OPh)(3) catalyst system. PMID:21968528
The relations between nuclear energy availability and nuclear plant safety are analyzed in the particular cases of naval propulsion nuclear boilers (aircraft carriers, submarines): safety objectives, present and potential risk analysis, optimization of the availability-safety couple, at the design stage and during operation (procedural rules related to the boiler state, real time decisions). 6 fig., 1 tab.
The authors propose an integrated indicator of pump-rod couplings that allows both the couplings and the pump operations to be appraised according to the given formula. (Formula provided). The dynamic relationships of rod operations were determined with nomographs. These relationships involve such factors as: the type and size of the sucker-rod string; the pressure load at the equalizer head and its correlation to threshold pressure at pump discharge; pump diameter; the rod weight and construction; and integral reliability indicators.
Predictions and measurements of a multimode waveguide interferometer operating in a fibre coupled, ``dual-mode'' regime are reported. With a 1.32 micrometer source, a complete switching cycle of the output beam is produced by a 10.0 nanometer incremental change in the 8.0 micrometer width of the hollow planar mirror waveguide. This equates to a fringe spacing of $\\sim\\lambda /130$. This is an order of magnitude smaller than previously reported results for this form of interferometer.
The electroweak-symmetry-breaking sector of the standard model can be weakly-coupled or can be strongly-coupled, which is characterized by some kinds of strong interaction among the Goldstone bosons of the electroweak-symmetry-breaking sector. In this paper, we summarize an investigation of probing the strong electroweak-symmetry-breaking effects at photon colliders. ((orig.)).
The electroweak-symmetry-breaking sector of the standard model can be weakly-coupled or can be strongly-coupled, which is characterized by some kinds of strong interaction among the Goldstone bosons of the electroweak-symmetry-breaking sector. In this paper, we summarize an investigation of probing the strong electroweak-symmetry-breaking effects at photon colliders. ((orig.)).
The vibration behavior of turbomachine bladings is described, and the behavior of different kinds of coupled low pressure stages was experimentally investigated. Besides purely stationary flow conditions, conditions were also considered where pulsating fl...
Unsymmetric diaryl alkynes were synthesized from the palladium-catalyzed decarboxylative coupling of aryl halides and propiolic acid using a continuous flow reaction system. This flow chemistry system continuously gave the desired products in moderate to good yields, and produced less byproduct than was formed in the batch reaction.
The kinetic parameters, ..cap alpha.. the coupling coefficient and tau-bar the mean neutron transit time have been determined using a reactor oscillator on the coupled-core of the Queen Mary College research reactor. By using correlation techniques it has proved possible to use detectors small enough to be inserted in the fuel tanks. It is shown that the simplified Baldwin model with one-group diffusion theory is inadequate to describe the kinetic behaviour and the experimentally-determined parameters are dependent upon the positioning of the detectors.
The high-frequency precessional mode of a hot-electron-stabilized magnetic configuration has previously been shown to be stable in a window of core-plasma mass. Under conditions of frequency matching, the resulting stable negative-energy precessional wave can be destabilized by coupling to positive-energy shear-Alfven waves. Coupling is avoided when the hot-electron precession frequency exceeds the core-plasma ion gyrofrequency.
The Albedo Theory was applied in order to develop an one-group algorithm for coupled neutron-gamma shielding calculations. The configuration analyzed consists of multilayered plane systems, where a incident neutron current generates gamma radiation through neutron-gamma reactions. The results obtained by Albedo Method and ANISN code have shown excellent agreement. (author)
The Albedo Theory was applied in order to develop an one-group algorithm for coupled neutron-gamma shielding calculations. The configuration analyzed consists of multilayered plane systems, where a incident neutron current generates gamma radiation through neutron-gamma reactions. The results obtained by Albedo Method and ANISN code have shown excellent agreement. (author)
A multi-group neutron-gamma cross-section library in DTF-IV format is supplemented with electron production matrix to generate a coupled neutron-gamma-electron library. This is realized by estimating the contributions from Compton scattering, pair production and photoelectric effect to the electron production cross-sections. A novel application of this new library, which involves transport of neutrons, gammas and electrons, for estimating the Compton current due to a pulse of radiation in air is discussed.
A multi-group neutron-gamma cross-section library in DTF-IV format is supplemented with electron production matrix to generate a coupled neutron-gamma-electron library. This is realized by estimating the contributions from Compton scattering, pair production and photoelectric effect to the electron production cross-sections. A novel application of this new library, which involves transport of neutrons, gammas and electrons, for estimating the Compton current due to a pulse of radiation in air is discussed.
A consistent mathematical derivation is given for the Sommerfeld fine structure electromagnetic coupling 1/?-bar 0=?0-bar 1/137.036. Following 't Hooft's holographic principle two complimentary forms of the derivation are given both leading to the E(?) theoretical value, namely ?-bar 0=(20)(1/?)4=137.082039311. The experimental value is subsequently found by projection as ?-bar 0(exp)=137/[cos(?/?-bar 0)]-bar 137.036.
pletely new PW fuel cell model had to be developed for CINDA. Several ...... following linear equation, which is used in the SINDA fuel cell model: ...
ObjectiveTo achieve osteochondral regeneration utilizing transplantation of cartilage-lineage cells and adequate scaffolds, it is essential to characterize the behavior of transplanted...Full Text Available
BackgroundThe evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria,...Full Text Available
The molecular structure, chemical properties, and biological function of the xyloglucan polysaccharide isolated from cell walls of suspension-cultured sycamore (Acer pseudoplatanus)...Full Text Available
... Program: Quallion Matrix Design (small cells) - Investigate the feasibly of a hybrid battery matrix composed of small D-sized cells for use in HEVs ...
The most advanced frontier of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is represented by the use of an HLA-partially matched relative as donor. In this type of transplantation, donor-derived natural killer (NK) cells, which are alloreactive towardtoward recipient cells, significantly contribute to the eradication of leukemia blasts. Alloreactive NK cells may also kill host dendritic cells and T lymphocytes, thus preventing graft-versus-host disease and graft rejection, respectively. Sophisticated strategies of adoptive infusion of T-cell lines/clones specific for the most life-threatening pathogens (namely cytomegalovirus, Epstein-Barr virus, Aspergillus and Adenovirus) have been envisaged, and successfully tested in a few pilot trials, to protect the recipient in the...
Gene expression is a fundamentally stochastic process, with randomness in transcription and translation leading to significant cell-to-cell variations in mRNA and protein levels. This variation...Full Text Available
Conditions were found in which Chlamydomonas reinhardi exhibits a circadian alteration of its cell surface, measured as ability to stick to glass. Under these same conditions the cells...Full Text Available
To examine the possibility that mast cells have a central role in the pathogenesis of hypersensitivity pneumonitis, 20 patients with this disease were studied with the aim of seeking evidence for mast...Full Text Available
Regulatory T cells are proposed to play a central role in the maintenance of immunological tolerance in the periphery, and studies in many animal models demonstrate their capacity to inhibit inflammatory...Full Text Available
There is a requirement for a noninvasive technique to monitor stem cell differentiation. Several candidates based on optical spectroscopy are discussed in this review: Fourier transform infrared (FTIR)...Full Text Available
Diverse cell polarity networks require positive feedback for locally amplifying distributions of signalling molecules at the plasma membrane1. Additional...Full Text Available
Morphological, Electrophysiological and Behavioral Investigations of the Nervous Tissue Developed from the Embryonic Matrix Zone Cells of the Dorsolateral Walls of Lateral Ventricles, Implanted into the Lesioned Regions of the Adult Rat's Brain
Jun 10, 2011 ... The PSSC is a picosatellite designed to test the space environment by providing a testbed to gather data on new solar cell technologies.
The present volume on modeling of batteries and fuel cells discusses the significance of the effectiveness factor for flooded porous electrodes, active pore distribution spectroscopy for characterizing porous battery electrodes, the agglomerate model for porous electrodes, and dynamic-performance measurements of battery cells for electric vehicles and other applications. Attention is given to mathematical modeling of a primary zinc/air battery, mathematical modeling of Grace Li-TiS2 cells, modeling of electrocrystallization processes in battery systems, and rotating disk electrode studies in molten Li/K carbonate eutectic. Topics addressed include the variability of nickel oxide cathode dissolution in molten carbonate fuel cells, water transport properties of fuel cell ionomers, modeling water content effects in polymer electrolyte fuel cells, and computer ...
Many mutations associated with retinal degeneration lead to the production of misfolded proteins by cells of the retina. Emerging evidence suggests that these abnormal proteins cause cell death...Full Text Available
Methods for improving the sensitivity of scintillation cells for radon concentration measurements were studied with emphasis on improving light collection efficiency. This allows the length and hence the volume of the cell to be increased. Variables studied were choice of scintillator material, its method of application and thickness, length of cell, cell material, type and configuration of reflectors, choice of photomultipliers, and factors affecting background. Response from various areas of the cell surface was studied with an alpha source and with radon filling. Coating the window with phosphor was found to be counter-productive. The optimum results obtained were with the inside of the cell (other than the window) covered with a thick layer of ZnS(Ag), or with a thick layer of reflective material coated with a thin layer of phosphor. With it, a 10 cm ...
Methods for improving the sensitivity of scintillation cells for radon concentration measurements were studied with emphasis on improving light collection efficiency. This allows the length and hence the volume of the cell to be increased. Variables studied were choice of scintillator material, its method of application and thickness, length of cell, cell material, type and configuration of reflectors, choice of photomultipliers, and factors affecting background. Response from various areas of the cell surface was studied with an alphy source and with radon filling. Coating the window with phosphor was found to be counter-productive. The optimum results obtained were with the inside of the cell (other than the window) covered with a thick layer of ZnS(Ag), or with a thick layer of reflective material coated with a thin layer of phosphor. With it, a 10 cm ...
Proliferating cells have been immunophenotypically characterized in lymph node and bronchoalveolar lavage (BAL) samples obtained from patients with active and inactive sarcoidosis with the cell-cycle-related...Full Text Available
Erythrocytes serve as reservoirs for cis- and trans-epoxyeicosatrienoic acids (EETs). Incubation of rat red blood cells (RBCs) with cis- and...Full Text Available
PASTICCINO (PAS) genes are required for coordinated cell division and differentiation during plant development. In loss-of-function pas mutants,...Full Text Available
PurposeTo analyze the expression of apoptosis and cell proliferation molecules in pterygium tissues of Chinese patients.MethodsThirty-three pterygia...Full Text Available
Proton exchange membrane (PEM) fuel cells are energy sources that have the ... for H2 /02 PEM fuel cells because their catalysts have properties suitable for 0 ...
Substantially genetically stable continuous human cell lines derived from normal human mammary epithelial cells (HMEC) and processes for making and using the same. In a preferred embodiment, the cell lines are derived by treating normal human mammary epithelial tissue with a chemical carcinogen such as benzo(a)pyrene. The novel cell lines serve as useful substrates for elucidating the potential effects of a number of toxins, carcinogens and mutagens as well as of the addition of exogenous genetic material. The autogenic parent cells from which the cell lines are derived serve as convenient control samples for testing. The cell lines are not neoplastically transformed, although they have acquired several properties which distinguish them from their normal progenitors. 2 tabs.
... with the loosening of Bush-era restrictions on stem cell research, a move that was widely hailed by the ... The first two explore the contentious debate over stem cell research. Using a series of intervie...
Cancer, by definition, is a proliferative disease. The fundamental scientific issue explored at the international symposium "Cell Proliferation and Chemical Carcinogenesis" was the impact of chemically...Full Text Available
Cells of the mononuclear phagocyte lineage have the capability to adhere to and fuse with each other and to differentiate into osteoclasts and giant cells. To investigate the macrophage adhesion/fusion...Full Text Available
Abstract: In many biological processes heterogeneity within clonal cell populations is an important issue. One of the most striking examples is a population of cancer cells in which after a common, identical death signal some cells die whereas others survive. The reason for this heterogeneity is intrinsic and extrinsic noise. In this paper we present a mechanistic multi-scale modeling framework for cell populations, in which the dynamics of every individual cell is captured by a parameter dependent stochastic differential equation (SDE). Heterogeneity among individual cells is accounted for by differences in parameter values, modeling extrinsic influences. Based on the statistical properties of the extrinsic noise and the SDE model for the individual cell, a partial differential equation (...
May 31, 2011 ... A Theoretical Solid Oxide Fuel Cell Model for System Controls and Stability Design AUTHOR(S): Kopasakis, George; Brinson, Thomas; Credle, ...
The existence of stem cells committed to the T lymphoid lineage was deduced from studying how rat T and B stem cells differ in their expression of membrane W3/13 antigen and in their susceptibility in vivo to gamma irradiation. Stem cell activity of rat bone marrow and fetal liver was measured in long-term radiation chimeras using B and T cell alloantigenic surface markers to identify the progeny of donor cells. Monoclonal mouse anti-rat thymocyte antibody W3/13 labeled approximately 40% of fetal liver cells and 60-70% of young rat bone marrow cells (40% brightly, 25% dimly). Bright, dim, and negative cells were separated on a fluorescence-activated cell sorter. All B and T lymphoid stem cells in fetal liver were W3/13 bright, as were B lymphoid stem cells in ...
We present a sample preparation method for measuring magnesium in individual whole lymphocytes by electron probe X-ray microanalysis. We use Burkitt's lymphoma cells in culture as the test sample and compare X-ray microanalysis of individual cells with atomic absorption analysis of pooled cell populations. We determine the magnesium peak-to-local continuum X-ray intensity ratio by electron probe X-ray microanalysis and calculate a mean cell magnesium concentration of 39 +/- 19 mmol/kg dry weight from analysis of 100 cells. We determine a mean cell magnesium concentration of 34 +/- 4 mmol/kg dry weight by atomic absorption analysis of pooled cells in three cell cultures. The mean cell magnesium concentrations determined by the two methods are not significantly different. We find a 10% coefficient of ...
We study the time evolution of a brane construction that is holographically dual to a strongly coupled gauge theory that dynamically breaks a global symmetry through the generation of an effective composite Higgs vev. The D3/D7 system with a background magnetic field or non-trivial gauge coupling (dilaton) profile displays the symmetry breaking. We study motion of the D7 brane in the background of the D3 branes. For small field inflation in the field theory the effective Higgs vev rolls from zero to the true vacuum value. We study what phenomenological dilaton profile generates the slow rolling needed, hence learning how the strongly coupled gauge theory's coupling must run. We note that evolution of our configuration in the holographic direction, representing the phyiscs of the strong interactions, can provide additional slowing of the roll time. Inflation seems to be favoured if the ...
The onset of double-diffusive convection in a couple-stress fluid-saturated horizontal porous layer is studied using linear and weak nonlinear stability analyses. The modified Darcy equation that includes the time derivative term and the inertia term is used to model the momentum equation. The expressions for stationary, oscillatory and finite-amplitude Rayleigh number are obtained as a function of the governing parameters. The effect of couple-stress parameter, solute Rayleigh number, Vadasz number and diffusivity ratio on stationary, oscillatory and finite-amplitude convection is shown graphically. It is found that the couple-stress parameter and the solute Rayleigh number have a stabilizing effect on stationary, oscillatory and finite-amplitude convection. The diffusivity ratio has a destabilizing effect in the case of stationary and finite-amplitude modes, with a dual effect in the case of oscillatory convection. The ...
Both linear and weakly nonlinear stability analyses are performed to study thermal convection in a rotating couple-stress fluid-saturated rigid porous layer. In the case of linear stability analysis, conditions for the occurrence of possible bifurcations are obtained. It is shown that Hopf bifurcation is possible due to Coriolis force, and it occurs at a lower value of the Rayleigh number at which the simple bifurcation occurs. In contrast to the nonrotating case, it is found that the couple-stress parameter plays a dual role in deciding the stability characteristics of the system, depending on the strength of rotation. Nonlinear stability analysis is carried out by constructing a set of coupled nonlinear ordinary differential equations using truncated representation of Fourier series. Sub-critical finite amplitude steady motions occur depending on the choice of physical parameters but at higher rotation rates oscillatory ...