297 research outputs found

    Gold nanoparticle and mean inactivation dose of human intestinal colon cancer HT-29 cells

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    Background: Mean inactivation dose is a useful radiobiological parameter for the comparison of human cell survival curves. Objectives: Given the importance and accuracy of these parameters, in the present study, the radio sensitivity enhancement of colon cancer (HT-29) cells in the presence of gold nanoparticles (GNPs) were studied using the mean inactivation dose (MID). Materials and Methods: Naked-GNPs with 50 nm diameters were incubated with HT-29 cells. The cytotoxicity and uptake of these particles on HT-29 cells were assessed. After determining the optimum GNPs concentration, the cells were incubated with gold nanoparticle for 24 hours. The change in the MID value as well as the radio sensitization enhancement under irradiation with 9 MV X-ray beams in the presence of GNPs were evaluated by multiple (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)MTS assay. Results: Cell survival in the presence of GNPs was more than 90% and the maximum uptake of GNPs was observed at 60 μM of gold nanoparticles. In contrast, in the presence of GNPs combined with radiation, cell survival and MID value significantly decreased, so that the radio sensitization enhancement was 1.4. Conclusions: Due to the significant reduction in the mean inactivation dose of colon cancer cells in the presence of gold nanoparticles, it seems that GNPs are suitable options to achieve a new approach in order to improve radiotherapy efficiency without increasing the prescribed radiation dose

    Numerical Investigation of Forced Convection of Nanofluid Flow in Microchannels: Effect of Adding Micromixer

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    In the present study, forced convection of CuO–water nanofluid in a two dimensional parallel plate microchannel with and without micromixers has been investigated numerically. Two horizontal hot baffles were inserted between the adiabatic plates and three vertical baffles, which were attached on the plates, worked as micromixers in order to improve the cooling process. The effect of Reynolds number, Re = 10, 30, 60, 100, and 150 and nanoparticles volume fraction, from 0 to 4%, were examined on flow field and heat transfer. Different geometrical configurations for the arrangement of the hot baffles were tested. A FORTRAN code based on finite volume method was developed to solve the governing equations and SIMPLER algorithm was used for handling the pressure-velocity coupling. Simulations showed that the presence of micromixers and increasing the Reynolds number as well as nanoparticles volume fraction, increase the average Nusselt number. In order to achieve maximum heat transfer, best arrangements for the baffles were reported. It was also observed that the size of recirculation zones, which are created behind the micromixer baffles, increases with increasing Reynolds number and leads to better cooling

    МОДЕЛИРОВАНИЕ РАСПРЕДЕЛЕНИЯ МАГНИТНОЙ ИНДУКЦИИ КОАКСИАЛЬНО-ЛИНЕЙНОГО ДВИГАТЕЛЯ С АКСИАЛЬНЫМ И РАДИАЛЬНЫМ НАПРАВЛЕНИЕМ НАМАГНИЧИВАНИЯ ПОСТОЯННЫХ МАГНИТОВ

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    The paper presents results of computer simulation and experimental study of magnetic induction distribution in a coaxial linear motor air gap throughout the length of the runner active part at different heights of the air gap between the runner and the inductor magnetic core for motors with axial and radial direction of the permanent magnets magnetization.Представлены результаты компьютерного моделирования и экспериментального исследования распределения магнитной индукции в воздушном зазоре по всей длине активной части бегуна коаксиально-линейного двигателя и при разных высотах воздушного зазора между бегуном и магнитопроводом индуктора для двигателей с аксиальным и радиальным направлением намагничивания постоянных магнитов.Представлені результати комп'ютерного моделювання та експериментального дослідження розподілу магнітної індукції в повітряному зазорі по всій довжині активної частини бігуна коаксіально-лінійного двигуна та при різних висотах повітряного зазору між бігуном та магнітопроводом індуктора для двигунів з аксіальним та радіальним напрямком намагнічування постійних магнітів

    Analysis of Magnetic Field Effects on Distributed Heat Sources in a Nanofluid-Filled Enclosure by Natural Convection

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    This paper studies the effect of magnetic field on the flow field and heat transfer of nanofluid with variable properties in the square enclosure with two arrangements of heat sources. Based upon numerical predictions, the effects of pertinent parameters such as the Rayleigh number (103, 104 and 105), the Hartmann number (0, 25, 50, 75 and 100) and the solid volume fraction (0 to 4%) on the flow and temperature fields and the heat transfer performance of the enclosure are examined. For the numerical solution of conservation equations, finite volume method and SIMPLER algorithm was used. The results show that the heat transfer rate influenced by district heat sources and it increases with distributing heat sources on the side walls and it increases with an increase of the Rayleigh number and volume fraction, but decreases with an increase of Hartmann number

    МОДЕЛИРОВАНИЕ РАБОТЫ КОАКСИАЛЬНО-ЛИНЕЙНЫХ ДВИГАТЕЛЕЙ С АКСИАЛЬНЫМ И РАДИАЛЬНЫМ НАПРАВЛЕНИЯМИ НАМАГНИЧИВАНИЯ ПОСТОЯННЫХ МАГНИТОВ ПРИ ДИНАМИЧЕСКОМ РЕЖИМЕ

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    Theoretical and experimental investigations of the amplitude, phase and inertia-power frequency characteristics of two types of coaxial-linear electric motors of back-and-forth motion with permanent magnets, which magnetization vector is directed axially and radially relative to the axis of the runner are carried out. The comparative analysis of characteristics of these motors is presented.Проведены теоретические и экспериментальные исследования амплитудных, фазовых и инерционно-силовых частотных характеристик двух типов коаксиально-линейных электрических двигателей возвратно-поступательного движения с постоянными магнитами, вектор намагничивания которых направлен аксиально и радиально по отношению к оси бегуна, а также выполнен сравнительный анализ характеристик этих двигателей.Проведено теоретичні та експериментальні дослідження амплітудних, фазових та інерційно-силових частотних характеристик двох типів коаксіально-лінійних електричних двигунів зворотно-поступального руху з постійними магнітами, вектор намагнічування яких направлений аксіально та радіально по відношенню до вісі бігуна, а також здійснено порівняльний аналіз характеристик цих двигунів

    Comparison of Secreted Frizzled-Related Protein -4 & -5 Promoter Methylation in Patients with Acute Myeloblastic Leukemia and Healthy Individuals

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    Background: DNA methylation patterns are often changed in cancer cells. Many of the tumor inhibitor genes are silenced by methylation, such as CDKN2B, p73, and the suppressor of cytokine signaling in patients with acute myeloblastic leukemia (AML). Secreted frizzled-related protein -4 and -5 (SFRP4, 5) are negative regulators of the Wnt signaling pathway. We aimed to evaluate the methylation status of SFRP4 and SFRP5 genes in patients with AML. Methods: Blood samples were isolated from 60 patients with AML and 30 healthy controls. DNA was exploited, treated with sodium bisulfite, and tested utilizing methylation-specific polymerase chain reaction with specific primers for methylated and unmethylated sequences of the SFRP4 and SFRP5 genes. Results: The frequency of unfit hypermethylation of SFRP4 and SFRP5 genes in patients with AML was characterized to be 50% (30/60) and 40% (24/60), respectively. Moreover, for all the subjects in the control group, methylation of SFRP4 and SFRP5 genes was negative. The spread of SFRP4 and SFRP5 promoter methylation in patients with AML was higher than the control population. Conclusion: Hypermethylation was seen in SFRP4 and SFRP5 genes in patients with AML

    Microsphere-assisted super-resolved Mirau digital holographic microscopy for cell identification

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    In this paper, we use a glass microsphere incorporated into a digital holographic microscope to increase the effective resolution of the system, aiming at precise cell identification. A Mirau interferometric objective is employed in the experiments, which can be used for a common-path digital holographic microscopy (DHMicroscopy) arrangement. High-magnification Mirau objectives are expensive and suffer from low working distances, yet the commonly used low-magnification Mirau objectives do not have high lateral resolutions. We show that by placing a glass microsphere within the working distance of a low-magnification Mirau objective, its effective numerical aperture can be increased, leading to super-resolved three-dimensional images. The improvement in the lateral resolution depends on the size and vertical position of microsphere, and by varying these parameters, the lateral resolution and magnification may be adjusted. We used the information from the super-resolution DHMicroscopy to identify thalassemia minor red blood cells (tRBCs). Identification is done by comparing the volumetric measurements with those of healthy RBCs. Our results show that microsphere-assisted super-resolved Mirau DHMicroscopy, being common path and off-axis in nature, has the potential to serve as a benchtop device for cell identification and biomedical measurements. © 2017 Optical Society of America

    Developing Culturally Appropriate Curricula: a cross-disciplinary exchange

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    Five academic colleagues from the University of Kent discuss work they have been doing to develop more culturally appropriate curricula in the disciplines of education, filmmaking, chemistry, economics and business

    Psychometrics properties of the Iranian version of fertility quality of life tool: a cross- sectional study

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    Background: Clinical measurement of quality of life for assessing reproductive problems should be considered as a standard investigation at the initial and continuing medical consultations with infertile people. Objective: The purpose of this study was comprehensive testing the psychometric properties of the Iranian version of fertility quality of life (FertiQol) as its use could be considerable due to the prevalence of infertility in Iran and the importance of evaluation of QoL in patients with infertility. Method and material: This was a psychometric properties study of 300 women referred to infertility clinic, Hormozgan, Iran. After linguistic validation of the Iranian version of MPCOSQ, a semi-structured interview was conducted to assess face validity. Consequently exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed to indicate the scale constructs. Discriminant validity was assessed using the known groups comparison. Convergent validity was evaluated by assessing the correlation between similar content on the 12-Item Short Form Health Survey, Hospital Anxiety and Depression Scale and FertiQol. In addition, reliability analysis was carried out with internal consistency. Results: The reliability of the Iranian version of the FertiQol questionnaire was satisfactory in all dimensions (Cronbach’s alpha ranging from 0.77 to 0.83 ). Six factors (emotional, mind/body, relational, social, environmental and tolerability) were extracted from the results of EFA with factor loading of the more than 0.3. Discrimination validity showed that FertiQol can differentiate between female patients with differing duration of infertility and number of children; this indicates favorable discrimination validity. Moreover, the results of convergent validity showed a favorable correlation between the related dimensions of 12-Item Short Form Health Survey (correlation ranging from 0.43 to 0.68 ), Hospital Anxiety and Depression Scale(correlation ranging from 0.47 to 0.52 ) and FertiQol. Conclusion: The Iranian version of FertiQol is valid and reliable for assessing infertility problems and the effects of treatment on quality of life of infertile patients referred for diagnosis and treatment at an Iranian infertility clinic. The clinical use of this measure is recommended for Iranian infertility clinics
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