285 research outputs found
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The Effects of Various Conductive Additive and Polymeric Binder Contents on the Performance of a Lithium-ion Composite
Fundamental electrochemical methods, cell performance tests, and physical characterization tests such as electron microscopy were used to study the effects of levels of the inert materials (acetylene black (AB), a nano-conductive additive, and polyvinylidene difluoride (PVDF), a polymer binder) on the power performance of lithium-ion composite cathodes. The electronic conductivity of the AB/PVDF composites at different compositions was measured with a four-point probe direct current method. The electronic conductivity was found to increase rapidly and plateau at a AB:PVDF ratio 0.2:1 (by weight), with 0.8:1 being the highest conductivity composition. AB:PVDF compositions along the plateau of 0.2:1, 0.4:1, 0.6:1 and 0.8:1 were investigated. Electrodes of each of those compositions were fabricated with different fractions of AB/PVDF to active material. It was found that at the 0.8:1 AB:PVDF, the rate performance improved with increases in the AB/PVDF loading, whereas at the 0.2:1 AB:PVDF, the rate performance improved with decreases in the AB/PVDF loading. The impedance of electrodes made with 0.6:1 AB:PVDF was low and relatively invariant
Longitudinal dispersion in wave-current-vegetation flow
The flow, turbulence and longitudinal dispersion in wave-current flow through submerged vegetation are experimentally examined. Laboratory experiments are carried out by superimposing progressive waves on a steady flow through simulated submerged vegetation. The resultant wave-currentvegetation interaction shows strong interfacial shear with increase in velocity due to wave-induced drift. The increase in turbulence in vegetation region is found to be about twice than in no wave case due to the additional mixing by wave motions. Solute experiments are conducted to quantify wavecurrent-vegetation longitudinal dispersion coefficient (WCVLDC) by routing method and by defining length and velocity scales for wave-current-vegetation flow, an empirical expression for WCVLDC has been proposed. Although increase in vertical diffusivity is observed compare to bare-bed channel, the shear effect is stronger which increases the magnitude of WCVLDC. The study can be a guideline to understand the combine hydrodynamics of wave, current and vegetation and to quantify the longitudinal dispersion therein.Экспериментально исследовано влияние растительности в жидкости на течение, интенсивность турбулентности и продольную дисперсию в системе волна – течение. В лабораторных экспериментах в установившемся течении создавались короткие волны, генерируемые волнопродуктором, и имитировалась подводная растительность (вегетация). Зона вегетации располагалась в придонной области и моделировалась системой вертикально подвешенных резиновых жгутов. Обнаружено возникновение больших сдвигов горизонтальной скорости течения в зоне перехода от области вегетации к чистой воде. Турбулентное перемешивание в зоне вегетации в два раза выше, чем в системе волна – течение без вегетации. Подводная растительность приводит к росту дисперсии движения вдоль канала. Увеличение скорости течения вызывает увеличение вертикальных сдвигов скорости и усиление продольной дисперсии. Вертикальное перемешивание с учетом вегетации на два порядка выше, чем при ее отсутствии. Выполнены серии экспериментов с целью количественной оценки влияния вегетации на дисперсию движения вдоль канала в зависимости от скорости течения, его глубины и концентрации подводной растительности. Предложены аппроксимации для экспериментально найденных зависимостей коэффициента продольной дисперсии от параметров задачи
Early Stem Cell Transplantation for Refractory Acute Leukemia after Salvage Therapy with High-Dose Etoposide and Cyclophosphamide
AbstractPrimary refractory acute leukemia (AL) has a poor prognosis, although some patients can be salvaged with allogeneic stem cell transplantation (SCT). Induction of complete remission (CR) with conventional chemotherapy before SCT may improve outcome in this patient population. Between March 1991 and October 2003, 59 adults with primary refractory AL were treated with continuous-infusion etoposide (VP) 2.4 to 3.0 g/m2 followed by cyclophosphamide (Cy) 6.0-7.2 g/m2 intravenously over 3 to 4 days with the intention of proceeding to SCT in CR1. Forty-two patients had acute myelogenous leukemia (AML), 13 patients had acute lymphoblastic leukemia (ALL), and 4 patients had acute biphenotypic leukemia. The most frequent nonhematologic toxicities were oral mucosal, gastrointestinal, and hepatic toxicities (44%, 20%, and 15% of patients, respectively). Thirty-two (57%) of 56 evaluable patients entered CR1 with a median time to platelet and neutrophil recovery of 22 and 26 days, respectively. CR1 rates were similar in AML (54%) and ALL/acute biphenotypic leukemia (67%; P = .52), and analysis of baseline characteristics did not reveal any predictors of response to VP/Cy. Twenty-nine of 32 CR1 patients subsequently underwent SCT (24 allogeneic and 5 autologous). Estimated 5-year event-free survival (EFS) and overall survival for the entire cohort are 23% and 26%, respectively. In the allogeneic SCT group, 5-year EFS was 52% for AML patients and 14% for ALL patients (P = .04), and only male sex was predictive of a favorable outcome (P = .03). VP/Cy is able to induce CR1 in most patients with primary refractory AL with an acceptable toxicity profile. Subsequent allogeneic SCT can lead to long-term EFS in a significant proportion of patients
Reversal of Dual Epigenetic Repression of Non-Canonical Wnt-5a Normalises Diabetic Corneal Epithelial Wound Healing and Stem Cells
AIMS/HYPOTHESIS: Diabetes is associated with epigenetic modifications including DNA methylation and miRNA changes. Diabetic complications in the cornea can cause persistent epithelial defects and impaired wound healing due to limbal epithelial stem cell (LESC) dysfunction. In this study, we aimed to uncover epigenetic alterations in diabetic vs non-diabetic human limbal epithelial cells (LEC) enriched in LESC and identify new diabetic markers that can be targeted for therapy to normalise corneal epithelial wound healing and stem cell expression.
METHODS: Human LEC were isolated, or organ-cultured corneas were obtained, from autopsy eyes from non-diabetic (59.87±20.89 years) and diabetic (71.93±9.29 years) donors. The groups were not statistically different in age. DNA was extracted from LEC for methylation analysis using Illumina Infinium 850K MethylationEPIC BeadChip and protein was extracted for Wnt phospho array analysis. Wound healing was studied using a scratch assay in LEC or 1-heptanol wounds in organ-cultured corneas. Organ-cultured corneas and LEC were transfected with WNT5A siRNA, miR-203a mimic or miR-203a inhibitor or were treated with recombinant Wnt-5a (200 ng/ml), DNA methylation inhibitor zebularine (1-20 µmol/l) or biodegradable nanobioconjugates (NBCs) based on polymalic acid scaffold containing antisense oligonucleotide (AON) to miR-203a or a control scrambled AON (15-20 µmol/l).
RESULTS: There was significant differential DNA methylation between diabetic and non-diabetic LEC. WNT5A promoter was hypermethylated in diabetic LEC accompanied with markedly decreased Wnt-5a protein. Treatment of diabetic LEC and organ-cultured corneas with exogenous Wnt-5a accelerated wound healing by 1.4-fold (p
CONCLUSIONS/INTERPRETATION: We provide the first account of epigenetic changes in diabetic corneas including dual inhibition of WNT5A by DNA methylation and miRNA action. Overall, Wnt-5a is a new corneal epithelial wound healing stimulator that can be targeted to improve wound healing and stem cells in the diabetic cornea
CDD: a Conserved Domain Database for protein classification
The Conserved Domain Database (CDD) is the protein classification component of NCBI's Entrez query and retrieval system. CDD is linked to other Entrez databases such as Proteins, Taxonomy and PubMed®, and can be accessed at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=cdd. CD-Search, which is available at http://www.ncbi.nlm.nih.gov/Structure/cdd/wrpsb.cgi, is a fast, interactive tool to identify conserved domains in new protein sequences. CD-Search results for protein sequences in Entrez are pre-computed to provide links between proteins and domain models, and computational annotation visible upon request. Protein–protein queries submitted to NCBI's BLAST search service at http://www.ncbi.nlm.nih.gov/BLAST are scanned for the presence of conserved domains by default. While CDD started out as essentially a mirror of publicly available domain alignment collections, such as SMART, Pfam and COG, we have continued an effort to update, and in some cases replace these models with domain hierarchies curated at the NCBI. Here, we report on the progress of the curation effort and associated improvements in the functionality of the CDD information retrieval system
Human Monoclonal Antibody Combination against SARS Coronavirus: Synergy and Coverage of Escape Mutants
BACKGROUND: Experimental animal data show that protection against severe acute respiratory syndrome coronavirus (SARS-CoV) infection with human monoclonal antibodies (mAbs) is feasible. For an effective immune prophylaxis in humans, broad coverage of different strains of SARS-CoV and control of potential neutralization escape variants will be required. Combinations of virus-neutralizing, noncompeting mAbs may have these properties. METHODS AND FINDINGS: Human mAb CR3014 has been shown to completely prevent lung pathology and abolish pharyngeal shedding of SARS-CoV in infected ferrets. We generated in vitro SARS-CoV variants escaping neutralization by CR3014, which all had a single P462L mutation in the glycoprotein spike (S) of the escape virus. In vitro experiments confirmed that binding of CR3014 to a recombinant S fragment (amino acid residues 318–510) harboring this mutation was abolished. We therefore screened an antibody-phage library derived from blood of a convalescent SARS patient for antibodies complementary to CR3014. A novel mAb, CR3022, was identified that neutralized CR3014 escape viruses, did not compete with CR3014 for binding to recombinant S1 fragments, and bound to S1 fragments derived from the civet cat SARS-CoV-like strain SZ3. No escape variants could be generated with CR3022. The mixture of both mAbs showed neutralization of SARS-CoV in a synergistic fashion by recognizing different epitopes on the receptor-binding domain. Dose reduction indices of 4.5 and 20.5 were observed for CR3014 and CR3022, respectively, at 100% neutralization. Because enhancement of SARS-CoV infection by subneutralizing antibody concentrations is of concern, we show here that anti-SARS-CoV antibodies do not convert the abortive infection of primary human macrophages by SARS-CoV into a productive one. CONCLUSIONS: The combination of two noncompeting human mAbs CR3014 and CR3022 potentially controls immune escape and extends the breadth of protection. At the same time, synergy between CR3014 and CR3022 may allow for a lower total antibody dose to be administered for passive immune prophylaxis of SARS-CoV infection
Reducing Glycosphingolipid Content in Adipose Tissue of Obese Mice Restores Insulin Sensitivity, Adipogenesis and Reduces Inflammation
Adipose tissue is a critical mediator in obesity-induced insulin resistance. Previously we have demonstrated that pharmacological lowering of glycosphingolipids and subsequently GM3 by using the iminosugar AMP-DNM, strikingly improves glycemic control. Here we studied the effects of AMP-DNM on adipose tissue function and inflammation in detail to provide an explanation for the observed improved glucose homeostasis. Leptin-deficient obese (LepOb) mice were fed AMP-DNM and its effects on insulin signalling, adipogenesis and inflammation were monitored in fat tissue. We show that reduction of glycosphingolipid biosynthesis in adipose tissue of LepOb mice restores insulin signalling in isolated ex vivo insulin-stimulated adipocytes. We observed improved adipogenesis as the number of larger adipocytes was reduced and expression of genes like peroxisome proliferator-activated receptor (PPAR) γ, insulin responsive glucose transporter (GLUT)-4 and adipsin increased. In addition, we found that adiponectin gene expression and protein were increased by AMP-DNM. As a consequence of this improved function of fat tissue we observed less inflammation, which was characterized by reduced numbers of adipose tissue macrophages (crown-like structures) and reduced levels of the macrophage chemo attractants monocyte-chemoattractant protein-1 (Mcp-1/Ccl2) and osteopontin (OPN). In conclusion, pharmacological lowering of glycosphingolipids by inhibition of glucosylceramide biosynthesis improves adipocyte function and as a consequence reduces inflammation in adipose tissue of obese animals
Femara® and the future: tailoring treatment and combination therapies with Femara
Long-term estrogen deprivation treatment for breast cancer can, in some patients, lead to the activation of alternate cellular pathways, resulting in the re-emergence of the disease. This is a distressing scenario for oncologists and patients, but recent intensive molecular and biochemical studies are beginning to unravel these pathways, revealing opportunities for new targeted treatments. Far from making present therapies redundant, these new discoveries open the door to novel combination therapies that promise to provide enhanced efficacy or overcome treatment resistance. Letrozole, one of the most potent aromatase inhibitors, is the ideal candidate for combination therapy; indeed, it is one of the most intensively studied aromatase inhibitors in the evolving combinatorial setting. Complementary to the use of combination therapy is the development of molecular tools to identify patients who will benefit the most from these new treatments. Microarray gene profiling studies, designed to detect letrozole-responsive targets, are currently under way to understand how the use of the drug can be tailored more efficiently to specific patient needs
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Comprehensive molecular characterization of gastric adenocarcinoma
Gastric cancer is a leading cause of cancer deaths, but analysis of its molecular and clinical characteristics has been complicated by histological and aetiological heterogeneity. Here we describe a comprehensive molecular evaluation of 295 primary gastric adenocarcinomas as part of The Cancer Genome Atlas (TCGA) project. We propose a molecular classification dividing gastric cancer into four subtypes: tumours positive for Epstein–Barr virus, which display recurrent PIK3CA mutations, extreme DNA hypermethylation, and amplification of JAK2, CD274 (also known as PD-L1) and PDCD1LG2 (also knownasPD-L2); microsatellite unstable tumours, which show elevated mutation rates, including mutations of genes encoding targetable oncogenic signalling proteins; genomically stable tumours, which are enriched for the diffuse histological variant and mutations of RHOA or fusions involving RHO-family GTPase-activating proteins; and tumours with chromosomal instability, which show marked aneuploidy and focal amplification of receptor tyrosine kinases. Identification of these subtypes provides a roadmap for patient stratification and trials of targeted therapies
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