181 research outputs found

    Spatially resolved pump-probe study of single-layer graphene produced by chemical vapor deposition

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    Carrier dynamics in single-layer graphene grown by chemical vapor deposition (CVD) is studied using spatially and temporally resolved pump-probe spectroscopy by measuring both differential transmission and differential reflection. By studying the expansion of a Gaussian spatial profile of carriers excited by a 1500-nm pump pulse with a 1761-nm probe pulse, we observe a diffusion of hot carriers of 5500 square centimeter per second. We also observe that the expansion of the carrier density profile decreases to a slow rate within 1 ps, which is unexpected. Furthermore, by using an 810-nm probe pulse we observe that both the differential transmission and reflection change signs, but also that this sign change can be permanently removed by exposure of the graphene to femtosecond laser pulses of relatively high fluence. This indicates that the differential transmission and reflection at later times may not be directly caused by carriers, but may be from some residue material from the sample fabrication or transfer process.Comment: 9 pages, 3 figure

    Removal mechanism of ultrasonic vibration and ELID composite plane grinding based on ultrasonic vibration of nano-ceramic workpiece

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    To realize the high efficiency mirror surface grinding of hard brittle materials (such as nano-ceramic material), this work firstly constructs an experimental platform for workpiece ultrasonic vibration and ELID combined plane grinding according to the processing mechanism of ultrasonic vibration assisted grinding and ELID grinding; then, based on the removal mechanism of hard brittle material, this work analyzes the kinematics of single abrasive grit with workpiece ultrasonic vibration plane grinding, and studies the effect of ELID plane grinding on the grinding depth; finally, based on the above work, this work proposes the mathematical model of material removal rate for the workpiece ultrasonic vibration and ELID combined plane grinding. Experimental results show that the material removal rate of combined plane grinding increases with the increase of the cutting depth and workpiece speed, the material removal rate of ultrasonic vibration and ELID combined grinding is higher than that of ELID grinding under the same conditions

    Effects of soluble epoxide hydrolase inhibitor on the expression of fatty acid synthase in peripheral blood mononuclear cell in patients with acute coronary syndrome

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    Abstract Background Researches have shown that soluble epoxide hydrolase inhibitors (sEHi) can protect against the development of atherosclerosis. Simultaneously, emerging evidences have implicated the association between fatty acid synthase (FAS) and acute coronary syndrome (ACS). We tested the hypothesis that sEHi could reduce the occurrence of ACS by regulating FAS. Methods Hospitalized ACS patients were selected as the ACS group (n = 65) while healthy normal subjects as the control group (n = 65). The blood levels of lipoproteins, fasting glucose, myocardial enzyme and high-sensitivity C-reactive protein (hs-CRP) were measured within 24 hours after admission. The peripheral blood mononuclear cells (PBMCs) were isolated and cultured. Trans-4-[4-(3-Adamantan-1-ylureido)cyclohexyloxy] benzoic acid (t-AUCB), a kind of sEHi, was then added to cells in various concentrations (0, 10, 50, 100 μmol/L). The expression of FAS, interleukin-6 (IL-6) mRNA and protein was detected by real-time PCR or Western blot, respectively. Results (1) Compared with the control group, the serum concentration of hs-CRP in the ACS group was increased (PPPPP Conclusions sEH inhibition regulated FAS and inhibited inflammation in cultured PBMCs from ACS patients, a mechanism that might prevent rupture of atherosclerotic lesions and protect against development of ACS.</p

    Significance of the lipid profile and endothelium-dependent vasodilatation in the pathogenesis of microvascular angina

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    Background: To investigate the significance of lipid disorders and endothelial dysfunction in the pathogenesis of microvascular angina. Methods: Levels of plasma lipids, lipoproteins and apolipoproteins were assessed in 21 patients with microvascular angina and 24 healthy subjects as controls. Also, the endothelium-dependent vasodilatation function was determined with high-resolution ultrasound in both groups. Results: Levels of serum total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), apolipoprotein B100 (ApoB100) and lipoprotein(a) [Lp(a)] in microvascular angina group were significantly higher than those in healthy subjects (each p < 0.05). The flow-mediated dilatation (FMD) in brachial arteries in patients with microvascular angina declined significantly as compared with that in control subjects (4.7 &#177; 1.9% vs. 12.8 &#177; 3.7%, p < 0.001). However, no significant difference was observed in response to nitroglycerin between groups (19.7 &#177; 8.1% vs. 21.2 &#177; 6.6%; p > 0.05). Linear correlation analysis revealed a significant negative correlation between the FMD of brachial arteries and the serum levels of LDL-C and Lp(a) in the microvascular angina group (r = -0.5125 and -0.4271, respectively, both p < 0.001). Subsequently, all subjects were pooled and divided into two groups (groups A and B) according to the degree of FMD in brachial arteries (A &#163; 4% and B > 4%). The serum LDL-C level was found to be significantly higher in group A than in group B (4.09 &#177; 0.65 mmol/L vs. 2.59 &#177; 0.49 mmol/L; p < 0.05). Conclusions: Plasma lipid disorders and vascular endothelial dysfunction may play important roles in the development of microvascular angina. The dysfunction of endothelium-dependent vasodilation was mainly associated with anomalies in LDL-C and Lp(a), and myocardial endothelial dysfunction was aggravated by lipid abnormalities in patients with microvascular angina

    Poly[bis­[μ-1,4-bis­(1H-imidazol-5-yl)benzene-κ2 N 3:N 3′]diformatomanganese(II)]

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    In the title compound, [Mn(CHO2)2(C12H10N4)2]n, the MnII atom and the benzene ring of the ligand lie on an inversion centers. The MnII atom has an octa­hedral coordination environment composed of four N atoms from two different symmetry-related N-heterocyclic ligands forming the basal plane, and two O atoms from symmetry-related formate anions occupying the apical positions. The title compound forms a two-dimensional (4,4) net parallel to (100) with all the MnII atoms lying on a plane. The crystal structure is consolidated by inter­molecular N—H⋯O hydrogen bonds.

    Enhanced interfacial interaction, mechanical properties and thermal stability of basalt fiber/epoxy composites with multi-scale reinforcements

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    In this work, epoxy (EP) resin composites with multi-scale reinforcements were prepared by hand lay-up and hot-pressing. The epoxy was reinforced with basalt fibers (BF) modified with a silane coupling agent (KH560). Carboxylated multi-walled carbon nanotubes (CNTs) were also grafted onto the surface of the modified BF using an impregnation method to achieve BF/CNTs multi-scale reinforcement. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that KH560 was successfully grafted onto the BF surface. Scanning electron microscopy (SEM), indicated a better resin adhesion on the BF and thus a stronger interfacial interaction in the BF/CNTs-reinforced composite. It was observed that the mass fraction of KH560 was a significant parameter in achieving desirable CNT immobilization and mechanical properties of the composites. At an optimal mass fraction of KH560 (5%), the tensile, flexural, and interlaminar shear strength (ILSS) of the modified composite (BF-5%KH560-CNT/EP) increased by 12.5%, 20.9%, and 25.5% respectively compared with the BF-washed/EP composite due to more efficient load transfer. In addition, compared with BF-washed/EP, the decomposition onset temperature of BF-5%KH560-CNT/EP increased from 387°C to 396°C, the maximum decomposition rate temperature increased from 400°C to 408°C, and the residual weight increased by 5.8%

    Clinicopathological characteristics and survival outcomes in Paget disease: a SEER populationâ based study

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    The objective of this study was to investigate the clinicopathological characteristics and survival outcomes of Paget disease (PD), Paget disease concomitant infiltrating duct carcinoma (PDâ IDC), and Paget disease concomitant intraductal carcinoma (PDâ DCIS). We identified 501,631 female patients from 2000 to 2013 in the Surveillance, Epidemiology, and End Results (SEER) database. These identified patients included patients with PD (n = 469), patients with PDâ IDC (n = 1832), and patients with PDâ DCIS (n = 1130) and infiltrating ductal carcinoma (IDC) (n = 498,076). Then, we compared the clinical characteristics of these patients with those who were diagnosed with IDC during the same period. The outcomes of these subtypes of breast carcinoma were different. Based on the overall survival, the patients with PDâ IDC had the worst prognosis (5â year survival rate = 84.1%). The PDâ DCIS had the best prognosis (5â year survival rate = 97.5%). Besides, among patients with Paget disease, the one who was married had a better prognosis than who were not. And, according to our research, the marital status was associated with the hormone receptor status in patients with PDâ IDC. Among three subtypes of Paget disease, patients with PDâ IDC had the worst prognosis. Besides, patients who were unmarried had worse outcomes. And the marital status of patients with PDâ IDC is associated with hormone status. The observation underscores the importance of individualized treatment.Patients with PDâ IDC have the worst prognosis. And the marital status of PDâ IDC patients is associated with hormone status and HER2 status. The observation underscores the importance of individualized treatment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144702/1/cam41475.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144702/2/cam41475_am.pd

    ATP synthase ecto-α-subunit: a novel therapeutic target for breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Treatment failure for breast cancer is frequently due to lymph node metastasis and invasion to neighboring organs. The aim of the present study was to investigate invasion- and metastasis-related genes in breast cancer cells <it>in vitro </it>and <it>in vivo</it>. Identification of new targets will facilitate the developmental pace of new techniques in screening and early diagnosis. Improved abilities to predict progression and metastasis, therapeutic response and toxicity will help to increase survival of breast cancer patients.</p> <p>Methods</p> <p>Differential protein expression in two breast cancer cell lines, one with high and the other with low metastatic potential, was analyzed using two-dimensional liquid phase chromatographic fractionation (Proteome Lab PF 2D system) followed by matrix-assisted laser desorption/time-of-flight mass spectrometry (MALDI-TOF/MS).</p> <p>Results</p> <p>Up regulation of α-subunit of ATP synthase was identified in high metastatic cells compared with low metastatic cells. Immunohistochemical analysis of 168 human breast cancer specimens on tissue microarrays revealed a high frequency of ATP synthase α-subunit expression in breast cancer (94.6%) compared to normal (21.2%) and atypical hyperplasia (23%) breast tissues. Levels of ATP synthase expression levels strongly correlated with large tumor size, poor tumor differentiation and advanced tumor stages (<it>P </it>< 0.05). ATP synthase α-subunit over-expression was detected on the surface of a highly invasive breast cancer cell line. An antibody against the ATP synthase α-subunit inhibited proliferation, migration and invasion in these breast cancer cells but not that of a non-tumor derived breast cell line.</p> <p>Conclusions</p> <p>Over-expression of ATP synthase α-subunit may be involved in the progression and metastasis of breast cancer, perhaps representing a potential biomarker for diagnosis, prognosis and a therapeutic target for breast cancer. This finding of this study will help us to better understand the molecular mechanism of tumor metastasis and to improve the screening, diagnosis, as well as prognosis and/or prediction of responses to therapy for breast cancer.</p

    Cholesterol: Controversies and consensus over 100 years of persistent efforts

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    Hypercholesterolemia is one of the major risk factors for the development of cardiovascular disease. There are still controversies surrounding cholesterol and blood lipid management. To explore an effective way to better optimize blood lipid management, over the past century, experts in the blood lipid field have been continuously debating, collaborating, and investigating. In this review, we will provide a brief overview of various cholesterol/lipid guidelines and discuss “cholesterol hypothesis,” low-density lipoprotein cholesterol target, intensive lipid-lowering therapy, and so on
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