499 research outputs found
The experimental study and numerical simulation of falling liquid film flow on horizontal tubes
This research is motivated by two observations: No report has been found so far in
studies of water falling film up to 100 mm intertube spacing. No simulation analysis
of film thickness under influence of intertube spacing in 3 dimensional models.
Therefore, to the best of author’s knowledge, this research aims to illuminate the
effects of intertube spacing between horizontal tubes on water falling film. An
experimental investigation of water falling film temperature was conducted to
explore the characteristics of heat transfer coefficients. In this study, the intertube
spacing from smallest size of 8 mm and up to 100 mm were analyzed for Reynolds
number range of 300 to 3300. The experimental data was extracted from calibrated
test rig and the effect is investigated using numerical study. On the other hand, the
effect of film thickness is numerically investigated for intertube spacing range of 10
mm to 40 mm. The numerical simulation was presented using the Volume of Fluid
(VOF) technique where it is capable in determining temperatures and thickness of
water falling film under influence of ambient factors. The experimental results reveal
that intertube spacing of 133 mm produced the maximum heat transfer coefficient of
6 kW/m² K with percentage of error below 7%. The results of the numerical
simulation indicate that the 40 mm intertube spacing presented the minimal average
film thickness of 0.3 mm within ± 50% errors. Implications of the results and future
research directions are also presented
Fundamental Sensor Development in Electrical Resistance Tomography
This paper will provide a fundamental understanding of one of the most commonly used tomography, Electrical Resistance Tomography (ERT). Unlike the other tomography systems, ERT displayed conductivity distribution in the Region of Interest (ROI) and commonly associated to Sensitivity Theorem in their image reconstruction. The fundamental construction of ERT includes a sensor array spaced equally around the imaged object periphery, a Data Acquisition (DAQ), image reconstruction and display system. Four ERT data collection strategies that will be discussed are Adjacent Strategy, Opposite Strategy, Diagonal Strategy and Conducting Boundary Strategy. We will also explain briefly on some of the possible Data Acquisition System (DAQ), forward and inverse problems, different arrangements for conducting and non-conducting pipes and factors that influence sensor arrays selections
Gene expression profiling of early intervertebral disc degeneration reveals a down-regulation of canonical Wnt signaling and caveolin-1 expression: implications for development of regenerative strategies
INTRODUCTION: Early degeneration of the intervertebral disc (IVD) involves a change in cellular differentiation from notochordal cells (NCs) in the nucleus pulposus (NP) to chondrocyte-like cells (CLCs). The purpose of this study was to investigate the gene expression profiles involved in this process using NP tissue from non-chondrodystrophic and chondrodystrophic dogs, a species with naturally occurring IVD degeneration. METHODS: Dual channel DNA microarrays were used to compare 1) healthy NP tissue containing only NCs (NC-rich), 2) NP tissue with a mixed population of NCs and CLCs (Mixed), and 3) NP tissue containing solely CLCs (CLC-rich) in both non-chondrodystrophic and chondrodystrophic dogs. Based on previous reports and the findings of the microarray analyses, canonical Wnt signaling was further evaluated using qPCR of relevant Wnt target genes. We hypothesized that caveolin-1, a regulator of Wnt signaling that showed significant changes in gene expression in the microarray analyses, played a significant role in early IVD degeneration. Caveolin-1 expression was investigated in IVD tissue sections and in cultured NCs. To investigate the significance of Caveolin-1 in IVD health and degeneration, the NP of 3-month-old Caveolin-1 knock-out mice was histopathologically evaluated and compared with the NP of wild-type mice of the same age. RESULTS: Early IVD degeneration involved significant changes in numerous pathways, including Wnt/β-catenin signaling. With regard to Wnt/β-catenin signaling, axin2 gene expression was significantly higher in chondrodystrophic dogs compared with non-chondrodystrophic dogs. IVD degeneration involved significant down-regulation of axin2 gene expression. IVD degeneration involved significant down-regulation in Caveolin-1 gene and protein expression. NCs showed abundant caveolin-1 expression in vivo and in vitro, whereas CLCs did not. The NP of wild-type mice was rich in viable NCs, whereas the NP of Caveolin-1 knock-out mice contained chondroid-like matrix with mainly apoptotic, small, rounded cells. CONCLUSIONS: Early IVD degeneration involves down-regulation of canonical Wnt signaling and Caveolin-1 expression, which appears to be essential to the physiology and preservation of NCs. Therefore, Caveolin-1 may be regarded an exciting target for developing strategies for IVD regeneration
Relacao entre o nivel de atividade fisica estimado pelo Baltimore Activity Scale for Intermittent Claudication e a pedometria em pacientes com claudicacao intermitente
CONTEXTO: Os pacientes com claudicação intermitente apresentam níveis reduzidos de atividade física. A Baltimore Activity Scale for Intermittent Claudication (BASIC) foi validada para quantificar o nível de atividade física destes pacientes. No entanto, esta validação se baseou em apenas dois dias de monitoramento com acelerômetros, de modo que ainda permanece incerto se a BASIC fornece informações sobre os níveis de atividade física semanal. OBJETIVO: Analisar a correlação entre o nível de atividade física estimada pela BASIC e o nível obtido pelo pedômetro em uma semana, em pacientes com claudicação intermitente. MÉTODOS: Foram estudados 150 pacientes com claudicação intermitente, com idade entre 30 e 80 anos. Foram obtidos os dados sociodemográficos e verificada a presença de comorbidades e de fatores de risco cardiovascular, e a BASIC. O pedômetro foi utilizado por sete dias consecutivos, sendo a análise feita em três diferentes períodos de monitorização (todos os dias, dias da semana e do fim de semana). RESULTADOS: Foi observada correlação entre a BASIC e a média de passos de todos os dias (rho=0,343; p<0,001), dos dias de semana (rho=0,336; p<0,001) e dos dias do final de semana (rho=0,317; p<0,001). CONCLUSÃO: Em pacientes com claudicação intermitente, o nível de atividade física estimado pela BASIC se correlaciona com o nível de atividade física semanal
Spatial and temporal changes in zooplankton abundance, biovolume, and size spectra in the neighboring waters of Japan: analyses using an optical plankton counter
Anxiolytic Effects of the MCH1R Antagonist TPI 1361-17
Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that acts on the MCH1 receptor. MCH1R is expressed widely throughout the brain, particularly in regions thought to be involved in the regulation of stress and emotional response. The role of MCH in anxiety has been controversial, however. Central administration of MCH has been reported to promote or reduce anxiety-like behaviors. The anxiolytic activity of several MCH1R antagonists has also been debated. To address this issue, we have tested whether TPI 1361-17, a highly specific and high affinity MCH1R antagonist, exerts anxiolytic effects in two commonly used models of anxiety, the elevated plus maze and the light–dark transition test. We show that this MCH1R antagonist exerts potent anxiolytic effects in both assays. Our study therefore supports previous studies indicating that MCH1R antagonists may be useful in the treatment of anxiety
Gene promoter hypermethylation in ductal lavage fluid from healthy BRCA gene mutation carriers and mutation-negative controls
INTRODUCTION: Female germline BRCA gene mutation carriers are at increased risk for developing breast cancer. The purpose of our study was to establish whether healthy BRCA mutation carriers demonstrate an increased frequency of aberrant gene promoter hypermethylation in ductal lavage (DL) fluid, compared with predictive genetic test negative controls, that might serve as a surrogate marker of BRCA1/2 mutation status and/or breast cancer risk. METHODS: The pattern of CpG island hypermethylation within the promoter region of a panel of four genes (RAR-β, HIN-1, Twist and Cyclin D2) was assessed by methylation-specific polymerase chain reaction using free DNA extracted from DL fluid. RESULTS: Fifty-one DL samples from 24 healthy women of known BRCA mutation status (7 BRCA1 mutation carriers, 12 BRCA2 mutation carriers and 5 controls) were available for methylation analysis. Eight of 19 (42.1%) BRCA mutation carriers were found to have at least one hypermethylated gene in the four-gene panel. Two BRCA mutation carriers, in whom aberrant methylation was found, also had duct epithelial cell atypia identified. No hypermethylation was found in DL samples from 5 negative controls(p = 0.13). CONCLUSION: We found substantial levels of aberrant methylation, with the use of a four-gene panel, in the fluid from the breasts of healthy BRCA mutation carriers compared with controls. Methylation analysis of free DNA in DL fluid may offer a useful surrogate marker for BRCA1/2 mutation status and/or breast cancer risk. Further studies are required for the evaluation of the specificity and predictive value of aberrant methylation in DL fluid for future breast cancer development in BRCA1/2 mutation carriers
Mobile electrical capacitance tomography (ECT) development for liquid-gas flow measurement
Electrical capacitance tomography (ECT) system is useful to obtain information on spatial distribution of dielectric material mixture inside a vessel. This paper discusses a sixteen-electrode mobile ECT sensing system which is developed non-invasively and non-intrusively. Emphases on the software development aspects are presented in several sections; initialization part, normalization part, calibration part, hardware communication part and the image reconstruction part. Thus, the liquid-gas concentration profile of the ECT system is successfully acquired using the software developed
An Intermittent Live Cell Imaging Screen for siRNA Enhancers and Suppressors of a Kinesin-5 Inhibitor
Kinesin-5 (also known as Eg5, KSP and Kif11) is required for assembly of a bipolar mitotic spindle. Small molecule inhibitors of Kinesin-5, developed as potential anti-cancer drugs, arrest cell in mitosis and promote apoptosis of cancer cells. We performed a genome-wide siRNA screen for enhancers and suppressors of a Kinesin-5 inhibitor in human cells to elucidate cellular responses, and thus identify factors that might predict drug sensitivity in cancers. Because the drug's actions play out over several days, we developed an intermittent imaging screen. Live HeLa cells expressing GFP-tagged histone H2B were imaged at 0, 24 and 48 hours after drug addition, and images were analyzed using open-source software that incorporates machine learning. This screen effectively identified siRNAs that caused increased mitotic arrest at low drug concentrations (enhancers), and vice versa (suppressors), and we report siRNAs that caused both effects. We then classified the effect of siRNAs for 15 genes where 3 or 4 out of 4 siRNA oligos tested were suppressors as assessed by time lapse imaging, and by testing for suppression of mitotic arrest in taxol and nocodazole. This identified 4 phenotypic classes of drug suppressors, which included known and novel genes. Our methodology should be applicable to other screens, and the suppressor and enhancer genes we identified may open new lines of research into mitosis and checkpoint biology
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