1,289 research outputs found

    Numerical study of transonic flow over oscillating airfoils using the full potential equation

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    The behavior of unsteady aerodynamic loadings on airfoils oscillating in transonic flow has been investigated numerically with particular attention given to supercritical airfoil sections. A previously developed finite difference method, which is based on the full potential equation and which uses a quasi-conservative scheme for proper capture of a shock wave motion, was employed for the present study. The unsteady aerodynamic pressure and load distributions on several different airfoil sections are presented with particular emphasis on the effects of free-stream Mach number, reduced frequency, and mean angle of attack. These parameters are demonstrated to have a significant effect on the behavior of the unsteady aerodynamic loadings. Comparisons of the present calculations with the exact inviscid solution and with the experimental results are also presented

    Radiocarbon Dating Using LSC

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    ABSTRACT Radiocarbon dating is a method of nuclear technique for obtaining age estimates on organic materials. Determination of wood (from Horyuji Shrine) and coral sample (from JCAC area) is due in Japan Chemical Analysis Center in the frame of Instructor Training Program. It uses SRM 4990C, wood and marble blanks. Preparation of samples, standard, and blanks is due by benzene synthesis method. Chemical Yield of preparation was 86,8%. Liquid scintillator is added and counted using Liquid Scintillation Counter (LSC) Wallac 1220 Quantulus at least 10 hours. The result of wood age is (1204 ± 37) years (BP) and coral age is (160 ± 45) years (BP) in term of confidence level 68%.   ABSTRAK Radiocarbon Dating merupakan salah satu aplikasi teknik nuklir yang digunakan untuk menentukan umur suatu obyek. Penentuan umur dengan metode tersebut terhadap sampel kayu (dari kuil Horyuji) dan kulit kerang (dari hasil penggalian di area JCAC) dilakukan di Japan Chemical Analysis Center dalam kerangka Instructor Training Program. Dalam penentuan tersebut digunakan standar SRM 4990C, blanko kayu dan kapur. Preparasi sample, standard dan blanko dilakukan dengan metode sintesis benzene. Kedapatulangan proses preparasi sebesar 86,8%. Benzene yang dihasilkan ditambah sintilator cair dan dilakukan pengukuran menggunakan Pencacah Sintilasi Cair Wallac 1220 Quantulus selama minimum 10 jam. Didapatkan umur dari kayu (1204 ± 37) tahun dan umur dari kulit kerang (7160 ± 45) tahun, dengan tingkat kepercayaan 68%

    Oxidative stress and breast cancer biomarkers : the case of the cytochrome P450 2E1

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    Aim: The aim of the study is to investigate the impact of the cytochrome P450 2E1, which is the most efficient CYP450 family member in generating reactive oxygen species (ROS), on cellular energy metabolism of breast cancer cells and therefore the effects of CYP2E1 on breast carcinogenesis. Methods: The estrogen receptor positive MCF-7 and the triple negative MDAMB- 231 breast cancer cells were used as experimental system to estimate ROS generation in these cells overexpressing CYP2E1 and treated with the glycolytic inhibitors 3-bromopyruvate or 2-deoxyglucose in the presence or absence of the CYP2E1 inhibitor chlormethiazole. Adenosine triphosphate (ATP) assay was used to measure ATP production and lactate assay to quantify the efflux of lactic acid in breast cancer cells treated with the CYP2E1 inhibitor chlormethiazole, the mitochondrial membrane potential and cell viability assays were employed to assess the pathway of cellular energy production and cellular death respectively after treatment of MCF-7 and MDA-MB-231 with the CYP2E1 activator acetaminophen or the CYP2E1 inhibitor chlormethiazole. Results: T he r esults i ndicated i ncreased ROS generation i n b reast c ancer c ells overexpressing C YP2E1. ROS generation was differentially regulated in breast cancer cells upon treatment with the CYP2E1 inhibitor chlormethiazole. Chlormethiazole treated MCF-7 cells exhibited reduced lactate efflux implying that CYP2E1 directly or indirectly regulates the glycolytic rate in these cells. Furthermore the mitochondrial membrane potential of both MCF-7 and MDA-MB-231 cells was differentially affected by the CYP2E1 activator acetaminophen versus the CYP2E1 inhibitor chlormethiazole providing additional support for the involvement of CYP2E1 in energy metabolic pathways in breast cancer. Conclusion: Results presented in this study provide evidence to suggest that CYP2E1 regulates cellular energy metabolism of breast cancer cells in a manner dependent on cell type and potentially on the clinical staging of the disease therefore CYP2E1 is a possible breast cancer biomarker

    Radiocarbon Dating Using LSC

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    ABSTRACT Radiocarbon dating is a method of nuclear technique for obtaining age estimates on organic materials. Determination of wood (from Horyuji Shrine) and coral sample (from JCAC area) is due in Japan Chemical Analysis Center in the frame of Instructor Training Program. It uses SRM 4990C, wood and marble blanks. Preparation of samples, standard, and blanks is due by benzene synthesis method. Chemical Yield of preparation was 86,8%. Liquid scintillator is added and counted using Liquid Scintillation Counter (LSC) Wallac 1220 Quantulus at least 10 hours. The result of wood age is (1204 ± 37) years (BP) and coral age is (160 ± 45) years (BP) in term of confidence level 68%.   ABSTRAK Radiocarbon Dating merupakan salah satu aplikasi teknik nuklir yang digunakan untuk menentukan umur suatu obyek. Penentuan umur dengan metode tersebut terhadap sampel kayu (dari kuil Horyuji) dan kulit kerang (dari hasil penggalian di area JCAC) dilakukan di Japan Chemical Analysis Center dalam kerangka Instructor Training Program. Dalam penentuan tersebut digunakan standar SRM 4990C, blanko kayu dan kapur. Preparasi sample, standard dan blanko dilakukan dengan metode sintesis benzene. Kedapatulangan proses preparasi sebesar 86,8%. Benzene yang dihasilkan ditambah sintilator cair dan dilakukan pengukuran menggunakan Pencacah Sintilasi Cair Wallac 1220 Quantulus selama minimum 10 jam. Didapatkan umur dari kayu (1204 ± 37) tahun dan umur dari kulit kerang (7160 ± 45) tahun, dengan tingkat kepercayaan 68%

    Spectroscopic Monitoring Observations of Nova V1724 Aql in 2012

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    Spectroscopic and photometric monitoring observations of nova Apl 2012 (V1724 Apl) were conducted at Koyama Astronomical Observatory, Fujii-Kurosaki Observatory and Bisei Astronomical Observatory. The nova was initially considered as an outbursting pre-main-sequence young stellar object. Our monitoring observations have revealed the nova to be a Fe II type classical nova. The temporal evolution of spectra and light curves of the nova were similar to those of a slow nova (e.g., V1280 Sco and V5558 Sgr). We observed no evidence of molecule formation in V1724 Aql in contrast with V2676 Oph in which dust formation occurred after the molecular formation in the nova outflow
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