264 research outputs found

    О выполнении максимальной токовой защиты в распределительных сетях

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    The paper contains a brief analysis of protection devices applied for various elements of distributive networks with a single-way supply. Advantages and disadvantages of maximum current protection with current-temporary characteristics which are independent and inversely dependent on current and some new possible methods for improvement of current protection sensitivity of distributive networks are considered in the paper.Выполнен краткий анализ устройств защиты, применяемой для различных элементов распределительных сетей с односторонним питанием. Рассмотрены достоинства и недостатки МТЗ с независимыми и обратнозависимыми от тока токовременными характеристиками и некоторые новые возможные пути повышения чувствительности токовых защит распределительных сетей

    Dense Antihydrogen: Its Production and Storage to Envision Antimatter Propulsion

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    We discuss the possibility that dense antihydrogen could provide a path towards a mechanism for a deep space propulsion system. We concentrate at first, as an example, on Bose-Einstein Condensate (BEC) antihydrogen. In a Bose-Einstein Condensate, matter (or antimatter) is in a coherent state analogous to photons in a laser beam, and individual atoms lose their independent identity. This allows many atoms to be stored in a small volume. In the context of recent advances in producing and controlling BECs, as well as in making antihydrogen, this could potentially provide a revolutionary path towards the efficient storage of large quantities of antimatter, perhaps eventually as a cluster or solid.Comment: 12 pages, 3 figure

    Fine-mapping of the HNF1B multicancer locus identifies candidate variants that mediate endometrial cancer risk.

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    Common variants in the hepatocyte nuclear factor 1 homeobox B (HNF1B) gene are associated with the risk of Type II diabetes and multiple cancers. Evidence to date indicates that cancer risk may be mediated via genetic or epigenetic effects on HNF1B gene expression. We previously found single-nucleotide polymorphisms (SNPs) at the HNF1B locus to be associated with endometrial cancer, and now report extensive fine-mapping and in silico and laboratory analyses of this locus. Analysis of 1184 genotyped and imputed SNPs in 6608 Caucasian cases and 37 925 controls, and 895 Asian cases and 1968 controls, revealed the best signal of association for SNP rs11263763 (P = 8.4 × 10(-14), odds ratio = 0.86, 95% confidence interval = 0.82-0.89), located within HNF1B intron 1. Haplotype analysis and conditional analyses provide no evidence of further independent endometrial cancer risk variants at this locus. SNP rs11263763 genotype was associated with HNF1B mRNA expression but not with HNF1B methylation in endometrial tumor samples from The Cancer Genome Atlas. Genetic analyses prioritized rs11263763 and four other SNPs in high-to-moderate linkage disequilibrium as the most likely causal SNPs. Three of these SNPs map to the extended HNF1B promoter based on chromatin marks extending from the minimal promoter region. Reporter assays demonstrated that this extended region reduces activity in combination with the minimal HNF1B promoter, and that the minor alleles of rs11263763 or rs8064454 are associated with decreased HNF1B promoter activity. Our findings provide evidence for a single signal associated with endometrial cancer risk at the HNF1B locus, and that risk is likely mediated via altered HNF1B gene expression

    О выборе характеристик срабатывания токовых защит линий в распределительных сетях с односторонним питанием

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    A brief analysis of operational characteristics of current protection with various current-time curves of distributive network lines with unsoldering is given in the paper. The paper considers possible measures directed on better technical modernization and expansion in the field of application of multi-stage microprocessor current protection in distributive networks with one-side power supply.Выполнен краткий анализ характеристик срабатывания токовых защит с различными времятоковыми характеристиками линий распределительной сети с отпайками. Рассмотрены возможные мероприятия по повышению технического совершенства и расширению области использования многоступенчатых микропроцессорных токовых защит в распределительных сетях с односторонним питанием

    Влияние насыщения трансформаторов тока на работу токовых защит

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    An analysis of the influence of instrument current transformer errors on operation of current protection of power supply diagram elements has been carried out in the paper. The paper shows the influence of an aperiodic component of transient current and secondary load on current  transformer errors.Peculiar operational features of measuring elements of electromechanical and microprocessor current protection with their joint operation with electromagnetic current transformers have been analyzed in the paper.Произведен анализ влияния погрешностей измерительных трансформаторов тока на работу токовых защит элементов схемы электроснабжения. Показано влияние апериодической составляющей тока переходного режима и вторичной нагрузки на погрешности трансформаторов тока.Произведен анализ особенностей работы измерительных органов электромеханических и микропроцессорных токовых защит при совместной работе с электромагнитными трансформаторами тока

    ПОВЫШЕНИЕ ТЕХНИЧЕСКОГО СОВЕРШЕНСТВА ТОКОВЫХ И ТОКОВЫХ НАПРАВЛЕННЫХ ЗАЩИТ РАСПРЕДЕЛИТЕЛЬНЫХ СЕТЕЙ

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    The paper considers principles of execution and methods for investigation of adaptive micro-processor protection of distributive systems with one- and two-side supply. Adaptive current protection  for the systems with one-side supply controls a moment  of non-symmetric  damage  initiation and automatically operate current of measuring elements. Systems with two-side supply presuppose combined usage of methods for determination of damage places and conventional method for execution of protection.Рассматриваются принципы выполнения и методы исследования адаптивных микропроцессорных защит распределительных сетей с одно- и двусторонним питанием. Адаптивная токовая защита для сетей с односторонним питанием контролирует момент  наступления  несимметричного повреждения и автоматически ток срабатывания измерительных органов. В сетях с двусторонним питанием предлагается комбинированное использование методов определения мест повреждений и традиционных методов выполнения защиты

    Применение компьютерных систем динамического моделирования для оценки поведения защит линий электропередачи

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    The paper considers problems pertaining to mathematical modeling of a transformer substation with protected electric power lines. It is proposed to use systems of dynamic modeling for investigations applying a method of calculative experiment with the purpose to evaluate behavior of protection and automation at short circuits. The paper contains comparison of results obtained with the help of program-simulated complex on the basis of a complex mathematical model of an object and with the help of dynamic modeling system – MathLab.Рассматриваются вопросы математического моделирования трансформаторной подстанции с защищаемыми линиями электропередачи. Предлагается использовать системы динамического моделирования для проведения исследований методом вычислительного эксперимента с целью оценки поведения защит и автоматики при коротких замыканиях. Проводится сопоставление результатов, полученных с помощью программного комплекса на основе комплексной математической модели объекта и с помощью системы динамического моделирования MathLab

    A Tissue Biomarker Panel Predicting Systemic Progression after PSA Recurrence Post-Definitive Prostate Cancer Therapy

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    Many men develop a rising PSA after initial therapy for prostate cancer. While some of these men will develop a local or metastatic recurrence that warrants further therapy, others will have no evidence of disease progression. We hypothesized that an expression biomarker panel can predict which men with a rising PSA would benefit from further therapy.A case-control design was used to test the association of gene expression with outcome. Systemic (SYS) progression cases were men post-prostatectomy who developed systemic progression within 5 years after PSA recurrence. PSA progression controls were matched men post-prostatectomy with PSA recurrence but no evidence of clinical progression within 5 years. Using expression arrays optimized for paraffin-embedded tissue RNA, 1021 cancer-related genes were evaluated-including 570 genes implicated in prostate cancer progression. Genes from 8 previously reported marker panels were included. A systemic progression model containing 17 genes was developed. This model generated an AUC of 0.88 (95% CI: 0.84-0.92). Similar AUCs were generated using 3 previously reported panels. In secondary analyses, the model predicted the endpoints of prostate cancer death (in SYS cases) and systemic progression beyond 5 years (in PSA controls) with hazard ratios 2.5 and 4.7, respectively (log-rank p-values of 0.0007 and 0.0005). Genes mapped to 8q24 were significantly enriched in the model.Specific gene expression patterns are significantly associated with systemic progression after PSA recurrence. The measurement of gene expression pattern may be useful for determining which men may benefit from additional therapy after PSA recurrence

    HMGA1 drives stem cell, inflammatory pathway, and cell cycle progression genes during lymphoid tumorigenesis

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    <p>Abstract</p> <p>Background</p> <p>Although the <it>high mobility group A1 </it>(<it>HMGA1</it>) gene is widely overexpressed in diverse cancers and portends a poor prognosis in some tumors, the molecular mechanisms that mediate its role in transformation have remained elusive. <it>HMGA1 </it>functions as a potent oncogene in cultured cells and induces aggressive lymphoid tumors in transgenic mice. Because HMGA1 chromatin remodeling proteins regulate transcription, <it>HMGA1 </it>is thought to drive malignant transformation by modulating expression of specific genes. Genome-wide studies to define HMGA1 transcriptional networks during tumorigenesis, however, are lacking. To define the HMGA1 transcriptome, we analyzed gene expression profiles in lymphoid cells from <it>HMGA1a </it>transgenic mice at different stages in tumorigenesis.</p> <p>Results</p> <p>RNA from lymphoid samples at 2 months (before tumors develop) and 12 months (after tumors are well-established) was screened for differential expression of > 20,000 unique genes by microarray analysis (Affymetrix) using a parametric and nonparametric approach. Differential expression was confirmed by quantitative RT-PCR in a subset of genes. Differentially expressed genes were analyzed for cellular pathways and functions using Ingenuity Pathway Analysis. Early in tumorigenesis, HMGA1 induced inflammatory pathways with NFkappaB identified as a major node. In established tumors, HMGA1 induced pathways involved in cell cycle progression, cell-mediated immune response, and cancer. At both stages in tumorigenesis, HMGA1 induced pathways involved in cellular development, hematopoiesis, and hematologic development. Gene set enrichment analysis showed that stem cell and immature T cell genes are enriched in the established tumors. To determine if these results are relevant to human tumors, we knocked-down HMGA1 in human T-cell leukemia cells and identified a subset of genes dysregulated in both the transgenic and human lymphoid tumors.</p> <p>Conclusions</p> <p>We found that <it>HMGA1 </it>induces inflammatory pathways early in lymphoid tumorigenesis and pathways involved in stem cells, cell cycle progression, and cancer in established tumors. <it>HMGA1 </it>also dyregulates genes and pathways involved in stem cells, cellular development and hematopoiesis at both early and late stages of tumorigenesis. These results provide insight into <it>HMGA1 </it>function during tumor development and point to cellular pathways that could serve as therapeutic targets in lymphoid and other human cancers with aberrant <it>HMGA1 </it>expression.</p

    The role of sialomucin CD164 (MGC-24v or endolyn) in prostate cancer metastasis

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    BACKGROUND: The chemokine stromal derived factor-1 (SDF-1 or CXCL12) and its receptor CXCR4 have been demonstrated to be crucial for the homing of stem cells and prostate cancers to the marrow. While screening prostate cancers for CXCL12-responsive adhesion molecules, we identified CD164 (MGC-24) as a potential regulator of homing. CD164 is known to function as a receptor that regulates stem cell localization to the bone marrow. RESULTS: Using prostate cancer cell lines, it was demonstrated that CXCL12 induced both the expression of CD164 mRNA and protein. Functional studies demonstrated that blocking CD164 on prostate cancer cell lines reduced the ability of these cells to adhere to human bone marrow endothelial cells, and invade into extracellular matrices. Human tissue microarrays stained for CD164 demonstrated a positive correlation with prostate-specific antigen levels, while its expression was negatively correlated with the expression of androgen receptor. CONCLUSION: Our findings suggest that CD164 may participate in the localization of prostate cancer cells to the marrow and is further evidence that tumor metastasis and hematopoietic stem cell trafficking may involve similar processes
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