62 research outputs found
Topological susceptibility in 2+1 flavors lattice QCD with domain-wall fermions
We measure the topological charge and its fluctuation for the gauge
configurations generated by the RBC and UKQCD Collaborations using 2+1 flavors
of domain-wall fermions on the 16^3 x 32 lattice (L \simeq 2 fm) with length 16
in the fifth dimension at inverse lattice spacing a^{-1} \simeq 1.62 GeV. From
the spectral flow of the Hermitian operator H_w (2 + \gamma_5 H_w)^{-1}, we
obtain the topological charge Q_t of each gauge configuration in the three
ensembles with light sea quark masses m_q a = 0.01, 0.02, and 0.03, and with
the strange quark mass fixed at m_s a = 0.04. From our result of Q_t, we
compute the topological susceptibilty \chi_t = /volume. In the small
m_q regime, our result of \chi_t agrees with the chiral effective theory. Using
the formula \chi_t = \Sigma / (m_u^{-1} + m_d^{-1} + m_s^{-1}) by
Leutwyler-Smilga, we obtain the chiral condensate \Sigma^MSbar(2 GeV) =
[259(6)(9) MeV]^3.Comment: 9 pages, 3 EPS figure
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
An Online Simultaneous Measurement of the Dual-Axis Straightness Error for Machine Tools
Vertical straightness errors are the key factor that affects the flatness of the workpiece during vertical machining. Traditionally, the individually measured and fitted vertical straightness errors of the X and Y axes are used to compensate the Z axis and, thus, obtain the flatness of the working table of the machine tool. However, it is difficult to measure and compensate the vertical straightness error of the desired position on the working table, not to mention the centroid variation effect of the working table on the measured data. In this study, an online dual-axis measurement system with repeatability (3σ) of 2.46 μm is developed to simultaneously measure X-axis and Y-axis straightness errors of the desired position of a working table. Furthermore, the measured data are utilized to establish a flatness error model to reduce the vertical straightness error of the working table such that the repeatability (3σ) of the measured flatness may be kept within a range of 0.65 μm
Hepatic Epithelioid Hemangioendothelioma in Taiwan: A Clinicopathologic Study of Six Cases in a Single Institution Over a 15-Year Period
Hepatic epithelioid hemangioendothelioma (HEH) is a rare vascular tumor of the liver typically with a slow but progressive course. We report the clinical and immunohistochemical characteristics of six cases from our institution between 1993 and 2008.
Methods: We searched the files of the Department of Pathology in National Taiwan University Hospital from January 1993 to December 2008 and found six cases of primary HEH. The clinical data were reviewed. The microscopic findings of each case were listed and analyzed. Confirmational immunoperoxidase stains were performed with antibodies against two endothelial markers (CD31 and CD34) and one epithelial marker (AE1/AE3 or cytokeratin).
Results: There were five female patients and one male patient with HEH, and the mean age was 45.3 years (range, 25–86 years). Most patients were asymptomatic and one third of cases presented as right costal or abdominal pain. Anemia was the most common laboratory abnormality. Liver failure developed at the advanced diffuse stage. Imaging studies revealed three different patterns as single nodular, multiple nodular, or diffuse types, reflecting different stages of disease and clinical symptoms. Microscopic findings included intracytoplasmic vascular lumen formation (100%), sinusoidal spreading (100%), vessel obliteration (66.7%), necrosis (66.7%), and cellular pleomorphism (16.7%). All cases expressed endothelial markers of CD31 and CD34, reflecting their vascular nature. Two patients received surgical treatment including partial liver resection and liver transplantation. Tumor recurrence developed 8 and 17 months later, respectively.
Conclusion: HEH showed insidious growth and frequent multicentricity, making early diagnosis and tumor resection difficult. Definite diagnosis totally relies on pathologic study. Tumor progression to hepatic failure is slow. Liver transplantation is currently the most prevalent treatment modality for HEH, but experience in Taiwan is limited due to the rarity of this disease
Evaluation of Transparent ITO/Nano-Ag/ITO Electrode Grown on Flexible Electrochromic Devices by Roll-to-Roll Sputtering Technology
This paper explores the flexible ITO/nano-Ag/ITO multilayer electrodes grown on polyethylene terephthalate (PET) substrates and processed by a continuous roll-to-roll (R2R) sputtering system at room temperature used for flexible electrochromic device (ECD) applications. The effect of the nano-Ag interlayer thickness on the electrical and optical properties of the flexible ITO/nano-Ag/ITO multilayer was thoroughly investigated. By using R2R-sputtered at an Ag DC power of 0.2 kW, we were able to achieve optimal ITO/nano-Ag/ITO multilayer that exhibits a high optical transmittance of 87.19% and the best figure of merit value (30.93 × 10−3 Ω−1). The EC performance and stability of the flexible devices were tested by a cathodic WO3 coloration. Coloring and bleaching tests show that ITO/nano-Ag/ITO multilayers are highly effective conductors, indicating that the R2R sputtering technique is a promising continuous sputtering process in preparing for the fabrication of optical devices and flexible electronics industries
A Geometric Error Measurement System for Linear Guideway Assembly and Calibration
Geometric errors, such as straightness, perpendicularity, and parallelism errors are determinant factors of both the accuracy and service life of a linear guideway. In this study, a multipurpose geometric error measurement system was mainly composed of a laser source and an in-lab-developed optical module is proposed. Two adjustment methods were used for the in-lab-developed optical module to calibrate the altitude angle of the pentaprism: The first one is designed for ease of operation based on Michelson principle using a laser interferometer as the light receiver, and the second is aimed at high calibration repeatability based on the autocollimator principle using the quadrant detector (QD) to replace the light receiver. The result shows that the residual errors of the horizontal straightness and the vertical straightness are within ±1.3 µm and ±5.3 µm, respectively, when referred to as the commercial laser interferometer. Additionally, the residual errors of perpendicularity and parallelism are within ±1.2 µm and ±0.1 µm, respectively, when referred to as the granite reference block
Introduction and Application of a Simple Probabilistic Liquefaction Hazard Analysis Program: HAZ45PL Module
The 2016 Meinong Earthquake hit southern Taiwan and many shallow foundation structures were damaged due to soil liquefaction. In response, the government initiated an investigation project to construct liquefaction potential maps for metropolitans in Taiwan. These maps were used for the preliminary safety assessment of infrastructures or buildings. However, the constructed liquefaction potential map used the pseudo-probabilistic approach, which has inconsistent return period. To solve the inconsistency, the probabilistic liquefaction hazard analysis (PLHA) was introduced. However, due to its complicated calculation procedure, PLHA is not easy and convenient for engineers to use without a specialized program, such as in Taiwan. Therefore, PLHA is not a popular liquefaction evaluation procedure in practice. This study presents a simple PLHA program, HAZ45PL Module, customized for Taiwan. Sites in Tainan City and Yuanlin City are evaluated using the HAZ45PL Module to obtain the hazard curve and to construct the liquefaction probability map. The liquefaction probability map provides probabilities of different liquefaction potential levels for engineers or owners to assess the performance of an infrastructure or to design a mitigation plan
Epigallocatechin Gallate Attenuates Proliferation and Oxidative Stress in Human Vascular Smooth Muscle Cells Induced by Interleukin-1β via Heme Oxygenase-1
Proliferation of vascular smooth muscle cells (VSMCs) triggered by inflammatory stimuli and oxidative stress contributes importantly to atherogenesis. The association of green tea consumption with cardiovascular protection has been well documented in epidemiological observations, however, the underlying mechanisms remain unclear. This study aimed to elucidate the effects of the most active green tea catechin derivative, (−)-epigallocatechin-3-gallate (EGCG), in human aortic smooth muscle cells (HASMCs), focusing particularly on the role of a potent anti-inflammatory and antioxidative enzyme heme oxygenase-1 (HO-1). We found that pretreatment of EGCG dose- and time-dependently induced HO-1 protein levels in HASMCs. EGCG inhibited interleukin- (IL-)1β-induced HASMC proliferation and oxidative stress in a dose-dependent manner. The HO-1 inducer CoPPIX decreased IL-1β-induced cell proliferation, whereas the HO-1 enzyme inhibitor ZnPPIX significantly reversed EGCG-caused growth inhibition in IL-1β-treated HASMCs. At the molecular level, EGCG treatment significantly activated nuclear factor erythroid-2-related factor (Nrf2) transcription activities. These results suggest that EGCG might serve as a complementary and alternative medicine in the treatment of these pathologies by inducing HO-1 expression and subsequently decreasing VSMC proliferation
An Experimental and Numerical Study of Pressure Drop and Hydraulic Behavior in Scaled-Down Fuel Bundle
This study presents a scaled-down single fuel assembly experiment to simulate the fuel in the spent fuel pool (SFP). From experiment results, this study obtained the relationship among pressure drop and velocity, the viscous resistance and inertial resistance factor. In computational fluid dynamics (CFD) simulations, the large number of fuel rod bundles is approximated with porous medium technique that imposes similar flow resistance to the motion of the fluid. Difference of the pressure drop between numerical and experimental results is within acceptable deviation
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