1,078 research outputs found

    Spontaneous Diaphragm Buckling Control Process on Piezoelectric Ultrasonic Microsensors for High Sensitivity

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    AbstractA new fabrication process has been proposed for high sensitivity piezoelectric ultrasonic microsensors based on spontaneous diaphragm buckling. The buckling deflection and direction of the diaphragms strongly affect the sensitivity of the sensors; upward-deflected diaphragms cause higher sensitivity. The sensor has a tensile piezoelectric layer and a compressive thermally oxidized silicon layer in the diaphragm and the buckling behavior is determined by the combination of the stresses. The fabrication process of the piezoelectric layer has been optimized for yield of spontaneously upward buckling and height of the buckling deflection. Totally the diaphragms over 90% of fabricated 196 ones buckle spontaneously upward with deflection over 5 sensors on them higher sensitivity by 6.7 times on average than that on flat ones

    Межфазный катализ: синтез гликозильных эфиров N-ацетилглюкозамина

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    В межфазной системе “твердое тело — органический растворитель” в присутствии каталитических количеств 15-краун-5 перацетат α-D-глюкозаминилхлорида легко образует гликозильные эфиры ряда карбоновых кислот. Полученные 1-0-β-ацилпиранозы идентифицированы с помощью ¹Н ЯМР спектроскопии.У міжфазній системі “тверде тіло — органічний розчинник” у присутності каталітичної кількості 15-краун-5 перацетат α-D-глюкозамінілхлориду легко утворює глікозильні естери ряду карбонових кислот. Отримані 1-O-β-ацилпіранози ідентифіковані за допомогою ¹Н ЯМР-спектроскопії.Peracetate of α-D-glucosaminyl chloride forms easily the N-acetylglucosamine glycosyl esters of the carboxylic acids range in the phase transfer system of “solid-organic solvent” in the presence of catalytic amounts of 15-crown-5. The structure of 1-O-β-acylpyranose synthesized was identified by ¹H NMR spectroscopy

    Orbital fluctuation theory in iron-based superconductors: s-wave superconductivity, structure transition, and impurity-induced nematic order

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    The main features in iron-based superconductors would be (i) the orthorhombic transition accompanied by remarkable softening of shear modulus, (ii) high-Tc superconductivity close to the orthorhombic phase, and (iii) nematic transition in the tetragonal phase. In this paper, we present a unified explanation for them, based on the orbital fluctuation theory, considering both the e-ph and the Coulomb interaction. It is found that a small e-ph coupling constant (λ 0.2\lambda ~ 0.2) is enough to produce large orbital (=charge quadrupole Oxz/yzO_{xz/yz}) fluctuations, which causes the s-wave superconductivity without sign reversal (s++s_{++}-wave state). The derived orbital fluctuations also cause the instability toward the structure transition due to the bound state formation of two orbitons with opposite momenta, which is called the "two-orbiton process". Moreover, impurity-induced non-local orbital order with C2C_2-symmetry is obtained when the orbital fluctuations are strong. This "impurity-induced nematic state" explains the in-plane anisotropy of resistivity in detwinned samples. We stress that (i)-(iii) are reproducible only when orbital fluctuations with respect to OxzO_{xz} and OyzO_{yz} charge quadrupoles are the most divergent. This fact ensures the reliability of the present model Hamiltonian and calculation.Comment: 13 pages, 9 figures, an article in a special issue on Iron Pnictide Superconductors in Solid State Communication

    Tuba, a Cdc42 GEF, is required for polarized spindle orientation during epithelial cyst formation

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    An RNAi screen picks Tuba out of the GTPase exchange factor (GEF) orchestra as a regulator of cell polarity in epithelial morphogenesis. (See also a companion paper from Rodriguez-Fraticelli et al., in this issue.

    Pharmacological Analyses of Protein Kinases Regulating Egg Maturation in Marine Nemertean Worms: A Review and Comparison with Mammalian Eggs

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    For development to proceed normally, animal eggs must undergo a maturation process that ultimately depends on phosphorylations of key regulatory proteins. To analyze the kinases that mediate these phosphorylations, eggs of marine nemertean worms have been treated with pharmacological modulators of intracellular signaling pathways and subsequently probed with immunoblots employing phospho-specific antibodies. This article both reviews such analyses and compares them with those conducted on mammals, while focusing on how egg maturation in nemerteans is affected by signaling pathways involving cAMP, mitogen-activated protein kinases, Src-family kinases, protein kinase C isotypes, AMP-activated kinase, and the Cdc2 kinase of maturation-promoting factor

    Influence of deposition strategies on tensile and fatigue properties in a wire + arc additive manufactured Ti-6Al-4V

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    This paper investigates the influence of two different deposition strategies, oscillation and parallel pass, on the tensile and high cycle fatigue properties of a wire + arc additive manufactured Ti-6Al-4V alloy in the as-built condition. In the oscillation build, the plasma torch and the wire feeder continuously oscillated across the wall thickness direction. In contrast, four single layers were deposited consecutively in the same direction along the wall length in the parallel pass build. Test specimens were manufactured in horizontal and vertical orientation with respect to the deposited layers. Compared with the parallel pass build, the oscillation build had lower static strength due to its coarser transformation microstructure. However, the elongation values were similar. The presence of columnar primary β grains has resulted in anisotropic elongation values. The vertical samples with loading axis parallel to the primary β grains showed 40% higher elongation than the horizontal samples. The fatigue strength was comparable with its wrought counterpart and greater than typical material by casting. At 107 cycles, fatigue strength of 600 MPa was achieved for the oscillation build vertical samples and the parallel pass build in both orientations. Only the oscillation build horizontal samples had lower fatigue strength of 500 MPa. Fractography analysis showed that most of the samples (about 70%) had crack initiation from pores, about 20% samples had crack initiated from microstructural features and the rest did not failed (runouts at 107 cycles)

    Effect of ramucirumab on ALBI grade in patients with advanced HCC: Results from REACH and REACH-2

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    Background & Aims: The albumin-bilirubin (ALBI) grade/score is derived from a validated nomogram to objectively assess prognosis and liver function in patients with hepatocellular carcinoma (HCC). In this post hoc analysis, we assessed prognosis in terms of survival by baseline ALBI grade and monitored liver function during treatment with ramucirumab or placebo using the ALBI score in patients with advanced HCC. Methods: Patients with advanced HCC, Child-Pugh class A with prior sorafenib treatment were randomised in REACH trials to receive ramucirumab 8 mg/kg or placebo every 2weeks. Datawere analysed by trial and as a meta-analysis of individual patientlevel data (pooled population) from REACH (alpha-fetoprotein>− 400 ng/ml) and REACH-2. Patients from REACHwith Child-Pugh class Bwere analysed as a separate cohort. The ALBI grades and scoreswere calculated at baseline and before each treatment cycle. Results: Baseline characteristics by ALBI grade were balanced between treatment arms among patients in the pooled population (ALBI-1, n = 231; ALBI-2, n = 296; ALBI-3, n = 7). Baseline ALBI grade was prognostic for overall survival (OS; ALBI grade 2 vs. 1; hazard ratio [HR]: 1.38 [1.13-1.69]), after adjusting for other significant prognostic factors. Mean ALBI scores remained stable in both treatment arms compared with baseline and were unaffected by baseline ALBI grade, macrovascular invasion, tumour response, geographical region, or prior locoregional therapy. Baseline ALBI grades 2 and 3 were associated with increased incidence of liver-specific adverse events and discontinuation rates in both treatments. Ramucirumab improved OS in patients with baseline ALBI grade 1 (HR 0.605 [0.445-0.824]) and ALBI grade 2 (HR 0.814 [0.630-1.051]. Conclusions: Compared with placebo, ramucirumab did not negatively impact liver function and improved survival irrespective of baseline ALBI grade

    Direct visualization of electroporation-assisted in vivo gene delivery to tumors using intravital microscopy – spatial and time dependent distribution

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    BACKGROUND: Electroporation is currently receiving much attention as a way to increase drug and DNA delivery. Recent studies demonstrated the feasibility of electrogene therapy using a range of therapeutic genes for the treatment of experimental tumors. However, the transfection efficiency of electroporation-assisted DNA delivery is still low compared to viral methods and there is a clear need to optimize this approach. In order to optimize treatment, knowledge about spatial and time dependency of gene expression following delivery is of utmost importance in order to improve gene delivery. Intravital microscopy of tumors growing in dorsal skin fold window chambers is a useful method for monitoring gene transfection, since it allows non-invasive dynamic monitoring of gene expression in tumors in a live animal. METHODS: Intravital microscopy was used to monitor real time spatial distribution of the green fluorescent protein (GFP) and time dependence of transfection efficiency in syngeneic P22 rat tumor model. DNA alone, liposome-DNA complexes and electroporation-assisted DNA delivery using two different sets of electric pulse parameters were compared. RESULTS: Electroporation-assisted DNA delivery using 8 pulses, 600 V/cm, 5 ms, 1 Hz was superior to other methods and resulted in 22% increase in fluorescence intensity in the tumors up to 6 days post-transfection, compared to the non-transfected area in granulation tissue. Functional GFP was detected within 5 h after transfection. Cells expressing GFP were detected throughout the tumor, but not in the surrounding tissue that was not exposed to electric pulses. CONCLUSIONS: Intravital microscopy was demonstrated to be a suitable method for monitoring time and spatial distribution of gene expression in experimental tumors and provided evidence that electroporation-assisted gene delivery using 8 pulses, 600 V/cm, 5 ms, 1 Hz is an effective method, resulting in early onset and homogenous distribution of gene expression in the syngeneic P22 rat tumor model

    MicroRNA-27a Regulates Lipid Metabolism and Inhibits Hepatitis C Virus Replication in Human Hepatoma Cells

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    The replication and infectivity of the lipotropic hepatitis C virus (HCV) are regulated by cellular lipid status. Among differentially expressed microRNAs (miRNAs), we found that miR-27a was preferentially expressed in HCV-infected liver over hepatitis B virus (HBV)-infected liver. Gene expression profiling of Huh-7.5 cells showed that miR-27a regulates lipid metabolism by targeting the lipid synthetic transcription factor RXRα and the lipid transporter ATP-binding cassette subfamily A member 1. In addition, miR-27a repressed the expression of many lipid metabolism-related genes, including FASN, SREBP1, SREBP2, PPARα, and PPARγ, as well as ApoA1, ApoB100, and ApoE3, which are essential for the production of infectious viral particles. miR-27a repression increased the cellular lipid content, decreased the buoyant density of HCV particles from 1.13 to 1.08 g/cm3, and increased viral replication and infectivity. miR-27a overexpression substantially decreased viral infectivity. Furthermore, miR-27a enhanced in vitro interferon (IFN) signaling, and patients who expressed high levels of miR-27a in the liver showed a more favorable response to pegylated IFN and ribavirin combination therapy. Interestingly, the expression of miR-27a was upregulated by HCV infection and lipid overload through the adipocyte differentiation transcription factor C/EBPα. In turn, upregulated miR-27a repressed HCV infection and lipid storage in cells. Thus, this negative feedback mechanism might contribute to the maintenance of a low viral load and would be beneficial to the virus by allowing it to escape host immune surveillance and establish a persistent chronic HCV infection
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