1,434 research outputs found

    The experimental study and numerical simulation of falling liquid film flow on horizontal tubes

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    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

    Study and design of an ultrasonic flow tomographic front-end multi level measurement system

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    With the rapid evolution of electro-acoustical technology, ultrasonic tomography has made considerable progress in industry. An ultrasonic tomography system provides non-invasive and non-intrusive flow visualisation that enhances the understanding of fluid flow processes. The function of ultrasonic tomography is to continuously monitor the dynamics of liquid flow without interrupting the flow. The ultrasonic tomography technique is fully supported by a front-end hardware system. The front end is defined as all the hardware circuitries, including the ultrasonic transducer up to the Analogue-to-Digital Convertors (ADCs), even though the primary focus is the analogue signal processing components. We present here the challenges and trade-offs in the implementation of a front-end system by first explaining the basic operation of such a system, and then indicating what particular performance parameters are needed to ensure optimal system operation. Based on the results from our research studies, we propose an improved front-end multi-level solution that is more accurate than previous solutions and provides real-time measurement capability

    Preoperative heart rate and myocardial injury after non-cardiac surgery: results of a predefined secondary analysis of the VISION study

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Funding for this study comes from more than 50 grants for VISION and its sub-studies: Canadian Institutes of Health Research (six grants); Heart and Stroke Foundation of Ontario (two grants); Academic Health Science Centres Alternative Funding Plan Innovation Fund Grant; Population Health Research Institute Grant; Clarity Research Group Grant; McMaster University, Department of Surgery, Surgical Associates Research Grant; Hamilton Health Science New Investigator Fund Grant; Hamilton Health Sciences Grant; Ontario Ministry of Resource and Innovation Grant; Stryker Canada, McMaster University, Department of Anesthesiology (two grants); Saint Joseph′s Healthcare, Department of Medicine (two grants); Father Sean O′Sullivan Research Centre (two grants); McMaster University, Department of Medicine (two grants); Hamilton Health Sciences Summer Studentships (six grants); McMaster University, Department of Clinical Epidemiology and Biostatistics Grant; McMaster University, Division of Cardiology Grant, and Canadian Network and Centre for Trials International Grant; Winnipeg Health Sciences Foundation Operating Grant; Diagnostic Services of Manitoba Research Grant; University of Manitoba, Faculty of Dentistry Operational Fund; Projeto Hospitais de Excelencia a Serviço do SUS grant from the Brazilian Ministry of Health in Partnership with Hcor (Cardiac Hospital Sao Paulo-SP); School of Nursing, Universidad Industrial de Santander; Grupo de Cardiología Preventiva, Universidad Autónoma de Bucaramanga; Fundación Cardioinfantil Instituto de Cardiología; Alianza Diagnóstica SA; University of Malaya Research Grant; and University of Malaya, Penyelidikan Jangka Pendek Grant. Roche Diagnostics provided the troponin T assays and some financial support for the VISION Study. Medical Research Council and British Journal of Anaesthesia clinical research training fellowship (grant reference MR/M017974/1 to T.E.F.A.); National Institute for Health Research professorship (to R.P.); British Journal of Anaesthesia and Royal College of Anaesthetists basic science fellowship (to G.A.); National Research Foundation of South Africa (to R.N.R.); Heart and Stroke Foundation of Ontario Career Investigator Award (to P.J.D.); Yusuf Chair in Cardiology (P.J.D.).Funding for this study comes from more than 50 grants for VISION and its sub-studies: Canadian Institutes of Health Research (six grants); Heart and Stroke Foundation of Ontario (two grants); Academic Health Science Centres Alternative Funding Plan Innovation Fund Grant; Population Health Research Institute Grant; Clarity Research Group Grant; McMaster University, Department of Surgery, Surgical Associates Research Grant; Hamilton Health Science New Investigator Fund Grant; Hamilton Health Sciences Grant; Ontario Ministry of Resource and Innovation Grant; Stryker Canada, McMaster University, Department of Anesthesiology (two grants); Saint Joseph′s Healthcare, Department of Medicine (two grants); Father Sean O′Sullivan Research Centre (two grants); McMaster University, Department of Medicine (two grants); Hamilton Health Sciences Summer Studentships (six grants); McMaster University, Department of Clinical Epidemiology and Biostatistics Grant; McMaster University, Division of Cardiology Grant, and Canadian Network and Centre for Trials International Grant;Winnipeg Health Sciences Foundation Operating Grant; Diagnostic Services of Manitoba Research Grant; University of Manitoba, Faculty of Dentistry Operational Fund; Projeto Hospitais de Excelencia a Serviço do SUS grant from the Brazilian Ministry of Health in Partnership with Hcor (Cardiac Hospital Sao Paulo-SP); School of Nursing, Universidad Industrial de Santander; Grupo de Cardiología Preventiva, Universidad Autónoma de Bucaramanga; Fundación Cardioinfantil Instituto de Cardiología; Alianza Diagnóstica SA; University of Malaya Research Grant; and University of Malaya, Penyelidikan Jangka Pendek Grant. Roche Diagnostics provided the troponin T assays and some financial support for the VISION Study. Medical Research Council and British Journal of Anaesthesia clinical research training fellowship (grant reference MR/M017974/1 to T.E.F.A.); National Institute for Health Research professorship (to R.P.); British Journal of Anaesthesia and Royal College of Anaesthetists basic science fellowship (to G.A.); National Research Foundation of South Africa (to R.N.R.); Heart and Stroke Foundation of Ontario Career Investigator Award (to P.J.D.); Yusuf Chair in Cardiology (P.J.D.)

    Fundamental Sensor Development in Electrical Resistance Tomography

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    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

    Optimal Surgical Extent for Memory and Seizure Outcome in Temporal Lobe Epilepsy

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    OBJECTIVE: Postoperative memory decline is an important consequence of anterior temporal lobe resection (ATLR) for temporal lobe epilepsy (TLE), and the extent of resection may be a modifiable factor. This study aimed to define optimal resection margins for cognitive outcome while maintaining a high rate of postoperative seizure freedom. METHODS: This cohort study evaluated the resection extent on postoperative structural MRI using automated voxel-based methods and manual measurements in 142 consecutive patients with unilateral drug refractory TLE (74 left, 68 right TLE) who underwent standard ATLR. RESULTS: Voxel-wise analyses revealed that postsurgical verbal memory decline correlated with resections of the posterior hippocampus and inferior temporal gyrus, whereas larger resections of the fusiform gyrus were associated with worsening of visual memory in left TLE. Limiting the posterior extent of left hippocampal resection to 55% reduced the odds of significant postoperative verbal memory decline by a factor of 8.1 (95% CI 1.5-44.4, p=0.02). Seizure freedom was not related to posterior resection extent, but to the piriform cortex removal after left ATLR. In right TLE, variability of the posterior extent of resection was not associated with verbal and visual memory decline or seizures after surgery. INTERPRETATION: The extent of surgical resection is an independent and modifiable risk factor for cognitive decline and seizures after left ATLR. Adapting the posterior extent of left ATLR might optimize postoperative outcome, with reduced risk of memory impairment while maintaining comparable seizure-freedom rates. The current, more lenient, approach might be appropriate for right ATLR. This article is protected by copyright. All rights reserved

    An Overview of Electrical Characterization Techniques for Biological Cell

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    In this paper, various electrical characterization techniques available for biological cell have been systematically reviewed. It covers both invasive and non-invasive approaches for population and single cell based studies. Examples of invasive technique consist of probing and patch clamp that measures the ionic current. However, depending on the applications, the non-invasive techniques are far more superior and popular. Some of the technique such as dielectric spectroscopy, electrorotation and dielectrophoresis measures the cell conductivity and dielectric constant. Furthermore, previous researchers proved that non-invasive technique may reduce the harmful effect on the cell due to electrical exposure. The review compares in terms of working principles, sample applications, advantages and limitations of each technique.&nbsp

    Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes

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    Copyright: © 2010 Stimpson et al.Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extrachromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.This work was supported by the Tumorzentrum Heidelberg/Mannheim grant (D.10026941)and by March of Dimes Research Foundation grant #1-FY06-377 and NIH R01 GM069514

    A novel benzimidazole derivative, MBIC inhibits tumor growth and promotes apoptosis via activation of ROS-dependent JNK signaling pathway in hepatocellular carcinoma

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    A prior screening programme carried out using MTT assay by our group identified a series of novel benzimidazole derivatives, among which Methyl 2-(5-fluoro-2- hydroxyphenyl)-1H- benzo[d]imidazole-5-carboxylate (MBIC) showed highest anticancer efficacy compared to that of chemotherapeutic agent, cisplatin. In the present study, we found that MBIC inhibited cell viability in different hepatocellular carcinoma (HCC) cell lines without exerting significant cytotoxic effects on normal liver cells. Annexin V-FITC/PI flow cytometry analysis and Western blotting results indicated that MBIC can induce apoptosis in HCC cells, which was found to be mediated through mitochondria associated proteins ultimately leading to the activation of caspase-3. The exposure to MBIC also resulted in remarkable impairment of HCC cell migration and invasion. In addition, treatment with MBIC led to a rapid generation of reactive oxygen species (ROS) and substantial activation of c-Jun-N-terminal kinase (JNK). The depletion of ROS by N-Acetyl cysteine (NAC) partially blocked MBIC-induced apoptosis and JNK activation in HCC cells. Finally, MBIC significantly inhibited tumor growth at a dose of 25 mg/kg in an orthotopic HCC mouse model. Taken together, these results demonstrate that MBIC may inhibit cell proliferation via ROS-mediated activation of the JNK signaling cascade in HCC cells

    The potential use of honey as a remedy for allergic diseases: a mini review

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    Honey has been conventionally consumed as food. However, its therapeutic properties have also gained much attention due to its application as a traditional medicine. Therapeutic properties of honey such as anti-microbial, anti-inflammatory, anti-cancer and wound healing have been widely reported. A number of interesting studies have reported the potential use of honey in the management of allergic diseases. Allergic diseases including anaphylaxis, asthma and atopic dermatitis (AD) are threatening around 20% of the world population. Although allergic reactions are somehow controllable with different drugs such as antihistamines, corticosteroids and mast cell stabilizers, modern dietary changes linked with allergic diseases have prompted studies to assess the preventive and therapeutic merits of dietary nutrients including honey. Many scientific evidences have shown that honey is able to relieve the pathological status and regulate the recruitment of inflammatory cells in cellular and animal models of allergic diseases. Clinically, a few studies demonstrated alleviation of allergic symptoms in patients after application or consumption of honey. Therefore, the objective of this mini review is to discuss the effectiveness of honey as a treatment or preventive approach for various allergic diseases. This mini review will provide insights into the potential use of honey in the management of allergic diseases in clinical settings

    The covid-19 pandemic situation in Malaysia: lessons learned from the perspective of population density

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    This paper attempts to ascertain the impacts of population density on the spread and severity of COVID-19 in Malaysia. Besides describing the spatio-temporal contagion risk of the virus, ultimately, it seeks to test the hypothesis that higher population density results in exacerbated COVID-19 virulence in the community. The population density of 143 districts in Malaysia, as per data from Malaysia’s 2010 population census, was plotted against cumulative COVID-19 cases and infection rates of COVID-19 cases, which were obtained from Malaysia’s Ministry of Health official website. The data of these three variables were collected between 19 January 2020 and 31 December 2020. Based on the observations, districts that have high population densities and are highly inter-connected with neighbouring districts, whether geographically, socio-economically, or infrastructurally, tend to experience spikes in COVID-19 cases within weeks of each other. Using a parametric approach of the Pearson correlation, population density was found to have a moderately strong relationship to cumulative COVID-19 cases (p-value of 0.000 and R2 of 0.415) and a weak relationship to COVID-19 infection rates (p-value of 0.005 and R2 of 0.047). Consequently, we provide several non-pharmaceutical lessons, including urban planning strategies, as passive containment measures that may better support disease interventions against future contagious diseases
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