60 research outputs found

    The New Approach to Estimation of the Hazard Function in Business Demography on Example of Data from New Zealand

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    The author presents the new methodology for the estimation of the hazard function for the new born enterprise`s survival rate called FIRM. The methodology is based on construction of a stochastic process and is examined in the Monte Carlo simulation study with real data. The dataset is provided by Statistics New Zealand and contains all enterprises born in period between 2001–2010. Enterprises are divided in clusters according to the number of employees and for each cluster individual simulations are made. Achieved coefficients of determination in clusters are around 90%. The author finds substantial differences in survival probability according to employee count size in the company. Simulations done in this study allow to estimate mean and standard deviation of life duration for enterprises and prediction of the hazard function for each cluster

    Application of HM-networks with inpatient claims in finding the memory capacity in information systems

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    To solve the problem of determining the memory capacity of the information systems (IS), the use of the stochastic model is proposed, based on the use of НМ (Howard-Matalytski) - queueing networks with revenues. This model allows one to take into account time dependencies of the message processing from their capacities, the possibility changes of the messages capacities over time and also the possibility of leaving messages from queues in nodes of IS, without getting into them appropriate processing. The expressions for the mean (expected) values of total message capacities in the IS nodes have been obtained

    Assessment and Relationship of Work Ability and the Level of Physical Activity Among Professional Bus Drivers

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    Numerous studies have shown that city bus drivers suffer from three key categories of health disorders: cardiovascular diseases, gastrointestinal disorders and musculoskeletal system issues, affecting the individual’s ability to work. The aim of this research was to assess the working ability of bus drivers and to determine the connection between the level of physical activity and the work ability in professional bus drivers. The study protocol included an assessment of participants’ work ability using the Work Ability Index (WAI) Questionnaire on a sample of 115 bus drivers. A statistical analysis was performed using the SAS System software package (SAS Institute Inc., North Carolina, USA). The questionnaire for determining the work ability index indicated good or excellent work ability in 78 (67.8%) of bus drivers. Moderate work ability that needed to be improved was recorded in 27 (23.5%) of drivers, and poor work ability that needed to be restored in 10 (8.7%). The results of the regression analysis show that increasing the average number of steps per day by a 1,000 increases the WAI score by 0.8. The obtained data should serve as an important argument for the design of future public health and kinesiology interventions to improve the work ability in professional bus drivers

    Analysis of Short Tandem Repeats by Parallel DNA Threading

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    The majority of studies employing short tandem repeats (STRs) require investigation of several of these genetic markers. As such, we demonstrate the feasibility of the trinucleotide threading (TnT) approach for scalable analysis of STRs. The TnT method represents a parallel amplification alternative that addresses the obstacles associated with multiplex PCR. In this study, analysis of the STR fragments was performed with capillary gel electrophoresis; however, it should be possible to combine our approach with the massive 454 sequencing platform to considerably increase the number of targeted STRs

    RNA-Seq Analysis Reveals Different Dynamics of Differentiation of Human Dermis- and Adipose-Derived Stromal Stem Cells

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    Tissue regeneration and recovery in the adult body depends on self-renewal and differentiation of stem and progenitor cells. Mesenchymal stem cells (MSCs) that have the ability to differentiate into various cell types, have been isolated from the stromal fraction of virtually all tissues. However, little is known about the true identity of MSCs. MSC populations exhibit great tissue-, location- and patient-specific variation in gene expression and are heterogeneous in cell composition.Our aim was to analyze the dynamics of differentiation of two closely related stromal cell types, adipose tissue-derived MSCs (AdMSCs) and dermal fibroblasts (FBs) along adipogenic, osteogenic and chondrogenic lineages using multiplex RNA-seq technology. We found that undifferentiated donor-matched AdMSCs and FBs are distinct populations that stay different upon differentiation into adipocytes, osteoblasts and chondrocytes. The changes in lineage-specific gene expression occur early in differentiation and persist over time in both AdMSCs and FBs. Further, AdMSCs and FBs exhibit similar dynamics of adipogenic and osteogenic differentiation but different dynamics of chondrogenic differentiation.Our findings suggest that stromal stem cells including AdMSCs and dermal FBs exploit different molecular mechanisms of differentiation to reach a common cell fate. The early mechanisms of differentiation are lineage-specific and are similar for adipogenic and osteogenic differentiation but are distinct for chondrogenic differentiation between AdMSCs and FBs

    Inhibition of protein disulfide isomerase induces differentiation of acute myeloid leukemia cells

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    Acute myeloid leukemia is a malignant disease of immature myeloid cells. Despite significant therapeutic effects of differentiation-inducing agents in some acute myeloid leukemia subtypes, the disease remains incurable in a large fraction of patients. Here we show that SK053, a thioredoxin inhibitor, induces differentiation and cell death of acute myeloid leukemia cells. Considering that thioredoxin knock-down with short hairpin RNA failed to exert antiproliferative effects in one of the acute myeloid leukemia cell lines, we used a biotin affinity probe-labeling approach to identify potential molecular targets for the effects of SK053. Mass spectrometry of proteins precipitated from acute myeloid leukemia cells incubated with biotinylated SK053 used as a bait revealed protein disulfide isomerase as a potential binding partner for the compound. Biochemical, enzymatic and functional assays using fluorescence lifetime imaging confirmed that SK053 binds to and inhibits the activity of protein disulfide isomerase. Protein disulfide isomerase knockdown with short hairpin RNA was associated with inhibition of cell growth, increased CCAAT enhancer-binding protein α levels, and induction of differentiation of HL-60 cells. Molecular dynamics simulation followed by the covalent docking indicated that SK053 binds to the fourth thioredoxin-like domain of protein disulfide isomerase. Differentiation of myeloid precursor cells requires the activity of CCAAT enhancer-binding protein α, the function of which is impaired in acute myeloid leukemia cells through various mechanisms, including translational block by protein disulfide isomerase. SK053 increased the levels of CCAAT enhancer-binding protein α and upregulated mRNA levels for differentiation-associated genes. Finally, SK053 decreased the survival of blasts and increased the percentage of cells expressing the maturation-associated CD11b marker in primary cells isolated from bone marrow or peripheral blood of patients with acute myeloid leukemia. Collectively, these results provide a proof-of-concept that protein disulfide isomerase inhibition has potential as a therapeutic strategy for the treatment of acute myeloid leukemia and for the development of small-molecule inhibitors of protein disulfide isomerase

    Parallel target selection by trinucleotide threading

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    DNA is the code for all life. Via intermediary RNA the information encoded by the genome is relayed to proteins executing the various functions in a cell. Together, this repertoire of inherently linked biological macromolecules determines all characteristics and features of a cell. Technological advancements during the last decades have enabled the pursuit of novel types of studies and the investigation of the cell and its constituents at a progressively higher level of detail. This has shed light on numerous cellular processes and on the underpinnings of several diseases. For the majority of studies focusing on nucleic acids, an amplification step has to be implemented before an analysis, scoring or interrogation method translates the amplified material into relevant biological information. This information can, for instance, be the genotype of particular SNPs or STRs, or the abundance level of a set of interesting transcripts. As such, amplification plays a significant role in nucleic acid assays. Over the years, a number of techniques – most notably PCR – has been devised to meet this amplification need, specifically or randomly multiplying desired regions. However, many of the approaches do not scale up easily rendering comprehensive studies cumbersome, time-consuming and necessitating large quantities of material.Trinucleotide threading (TnT) – forming the red thread throughout this thesis – is a multiplex amplification method, enabling simultaneous targeted amplification of several nucleic acid regions in a specific manner. TnT begins with a controlled linear DNA thread formation, each type of thread corresponding to a segment of interest, by a gap-fill reaction using a restricted trinucleotide set. The whole collection of created threads is subsequently subjected to an exponential PCR amplification employing a single primer pair. The generated material can thereafter be analyzed with a multitude of readout and detection platforms depending on the issue or characteristic under consideration.TnT offers a high level of specificity by harnessing the inherent specificities of a polymerase and a ligase acting on a nucleotide set encompassing three out of the four nucleotide types. Accordingly, several erroneous events have to occur in order to produce artifacts. This necessitates override of a number of control points.The studies constituting this thesis demonstrate integration of the TnT amplification strategy in assays for analysis of various aspects of DNA and RNA. TnT was adapted for expression profiling of intermediately-sized gene sets using both conventional DNA microarrays and massively parallel second generation 454 sequencing for readout. TnT, in conjunction with 454 sequencing, was also employed for allelotyping, defined as determination of allele frequencies in a cohort. In this study, 147 SNPs were simultaneously assayed in a pool comprising genomic DNA of 462 individuals. Finally, TnT was recruited for parallel amplification of STR loci with detection relying on capillary gel electrophoresis. In all investigations, the material generated with TnT was of sufficient quality and quantity to produce reliable and accurate biological information.Taken together, TnT represents a viable multiplex amplification technique permitting parallel amplification of genomic segments, for instance harboring polymorphisms, or of expressed genes. In addition to these, this versatile amplification module can be implemented in assays targeting a range of other features of genomes and transcriptomes.QC 2010081

    Zero energy buildings in the logistics warehouse systems

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    The article discusses the evaluation of possible reductions of energy consumption in warehouse buildings and the analysis of construction and functioning of modern storage warehouses. For a warehouse the following are presented: operation evaluation measures and indexes, an energy balance, ideas for improvements in terms of energy conservation in particular functioning zones
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