675 research outputs found
Fabrication of a Flexible Micro CO Sensor for Micro Reformer Applications
Integration of a reformer and a proton exchange membrane fuel cell (PEMFC) is problematic due to the presence in the gas from the reforming process of a slight amount of carbon monoxide. Carbon monoxide poisons the catalyst of the proton exchange membrane fuel cell subsequently degrading the fuel cell performance, and necessitating the sublimation of the reaction gas before supplying to fuel cells. Based on the use of micro-electro-mechanical systems (MEMS) technology to manufacture flexible micro CO sensors, this study elucidates the relation between a micro CO sensor and different SnO2 thin film thicknesses. Experimental results indicate that the sensitivity increases at temperatures ranging from 100–300 °C. Additionally, the best sensitivity is obtained at a specific temperature. For instance, the best sensitivity of SnO2 thin film thickness of 100 nm at 300 °C is 59.3%. Moreover, a flexible micro CO sensor is embedded into a micro reformer to determine the CO concentration in each part of a micro reformer in the future, demonstrating the inner reaction of a micro reformer in depth and immediate detection
3D Magneto-Hydrodynamic Simulations of Parker Instability with Cosmic Rays
This study investigates Parker instability in an interstellar medium (ISM)
near the Galactic plane using three-dimensional magneto-hydrodynamic
simulations. Parker instability arises from the presence of a magnetic field in
a plasma, wherein the magnetic buoyant pressure expels the gas and cause the
gas to move along the field lines. The process is thought to induce the
formation of giant molecular clouds in the Galaxy. In this study, the effects
of cosmic-ray (CR) diffusion are examined. The ISM at equilibrium is assumed to
comprise a plasma fluid and a CR fluid at various temperatures, with a uniform
magnetic field passing through it in the azimuthal direction of the Galactic
disk. After a small perturbation, the unstable gas aggregates at the footpoint
of the magnetic fields and forms dense blobs. The growth rate of the
instability increases with the strength of the CR diffusion. The formation of
dense clouds is enhanced by the effect of cosmic rays (CRs), whereas the shape
of the clouds depends sensitively on the initial conditions of perturbation.Comment: 4 pages, Computer Physics Communications 2011, 182, p177-17
A positive feedback loop of IL-17B-IL-17RB activates ERK/β-catenin to promote lung cancer metastasis
Inflammation contributes to the development and progression of cancer. Interleukin-17 (IL-17) is an inflammatory cytokine that functions in inflammation and cancer, as well as several other cellular processes. In this study, we investigated the roles and the prognostic value of IL-17 and the IL-17 receptor (IL-17R) in lung cancer. Gene expression microarray analysis followed by Kaplan-Meier survival curve showed that IL-17B was associated with poor patient survival, and IL-17B receptor (IL-17RB) was up-regulated in lung cancer tissue compared with normal tissue. Expression of IL-17RB was associated with lymph node metastasis and distant metastasis, as well as poor patient survival. IL-17RB overexpression significantly increased cancer cell invasion/migration and metastasis in vitro and in vivo. IL-17RB induced ERK phosphorylation, resulting in GSK3β inactivation and leading to β-catenin up-regulation. IL-17RB also participated in IL-17B synthesis via the ERK pathway. IL-17RB activation is required for IL-17B-mediated ERK phosphorylation. Taken together, IL-17B-IL-17RB signaling and ERK participate in a positive feedback loop that enhances invasion/migration ability in lung cancer cell lines. IL-17RB may therefore serve as an independent prognostic factor and a therapeutic target for lung cancer
The lift industry in Hong Kong : regulatory action and capacity building
published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio
High expression FUT1 and B3GALT5 is an independent predictor of postoperative recurrence and survival in hepatocellular carcinoma.
Cancer may arise from dedifferentiation of mature cells or maturation-arrested stem cells. Previously we reported that definitive endoderm from which liver was derived, expressed Globo H, SSEA-3 and SSEA-4. In this study, we examined the expression of their biosynthetic enzymes, FUT1, FUT2, B3GALT5 and ST3GAL2, in 135 hepatocellular carcinoma (HCC) tissues by qRT-PCR. High expression of either FUT1 or B3GALT5 was significantly associated with advanced stages and poor outcome. Kaplan Meier survival analysis showed significantly shorter relapse-free survival (RFS) for those with high expression of either FUT1 or B3GALT5 (P = 0.024 and 0.001, respectively) and shorter overall survival (OS) for those with high expression of B3GALT5 (P = 0.017). Combination of FUT1 and B3GALT5 revealed that high expression of both genes had poorer RFS and OS than the others (P < 0.001). Moreover, multivariable Cox regression analysis identified the combination of B3GALT5 and FUT1 as an independent predictor for RFS (HR: 2.370, 95% CI: 1.505-3.731, P < 0.001) and OS (HR: 2.153, 95% CI: 1.188-3.902, P = 0.012) in HCC. In addition, the presence of Globo H, SSEA-3 and SSEA-4 in some HCC tissues and their absence in normal liver was established by immunohistochemistry staining and mass spectrometric analysis
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Multi-scale symbolic entropy analysis provides prognostic prediction in patients receiving extracorporeal life support
Introduction: Extracorporeal life support (ECLS) can temporarily support cardiopulmonary function, and is occasionally used in resuscitation. Multi-scale entropy (MSE) derived from heart rate variability (HRV) is a powerful tool in outcome prediction of patients with cardiovascular diseases. Multi-scale symbolic entropy analysis (MSsE), a new method derived from MSE, mitigates the effect of arrhythmia on analysis. The objective is to evaluate the prognostic value of MSsE in patients receiving ECLS. The primary outcome is death or urgent transplantation during the index admission. Methods: Fifty-seven patients receiving ECLS less than 24 hours and 23 control subjects were enrolled. Digital 24-hour Holter electrocardiograms were recorded and three MSsE parameters (slope 5, Area 6–20, Area 6–40) associated with the multiscale correlation and complexity of heart beat fluctuation were calculated. Results: Patients receiving ECLS had significantly lower value of slope 5, area 6 to 20, and area 6 to 40 than control subjects. During the follow-up period, 29 patients met primary outcome. Age, slope 5, Area 6 to 20, Area 6 to 40, acute physiology and chronic health evaluation II score, multiple organ dysfunction score (MODS), logistic organ dysfunction score (LODS), and myocardial infarction history were significantly associated with primary outcome. Slope 5 showed the greatest discriminatory power. In a net reclassification improvement model, slope 5 significantly improved the predictive power of LODS; Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in MODS. In an integrated discrimination improvement model, slope 5 added significantly to the prediction power of each clinical parameter. Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in sequential organ failure assessment. Conclusions: MSsE provides additional prognostic information in patients receiving ECLS. Electronic supplementary material The online version of this article (doi:10.1186/s13054-014-0548-3) contains supplementary material, which is available to authorized users
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Outlier-resilient complexity analysis of heartbeat dynamics
Complexity in physiological outputs is believed to be a hallmark of healthy physiological control. How to accurately quantify the degree of complexity in physiological signals with outliers remains a major barrier for translating this novel concept of nonlinear dynamic theory to clinical practice. Here we propose a new approach to estimate the complexity in a signal by analyzing the irregularity of the sign time series of its coarse-grained time series at different time scales. Using surrogate data, we show that the method can reliably assess the complexity in noisy data while being highly resilient to outliers. We further apply this method to the analysis of human heartbeat recordings. Without removing any outliers due to ectopic beats, the method is able to detect a degradation of cardiac control in patients with congestive heart failure and a more degradation in critically ill patients whose life continuation relies on extracorporeal membrane oxygenator (ECMO). Moreover, the derived complexity measures can predict the mortality of ECMO patients. These results indicate that the proposed method may serve as a promising tool for monitoring cardiac function of patients in clinical settings
Flux tunable graphene-based superconducting quantum circuits coupled to 3D cavity
Correlation between transmon and its composite Josephson junctions (JJ) plays
an important role in designing new types of superconducting qubits based on
quantum materials. It is desirable to have a type of device that not only
allows exploration for use in quantum information processing but also probing
intrinsic properties in the composite JJs. Here, we construct a flux-tunable 3D
transmon-type superconducting quantum circuit made of graphene as a
proof-of-concept prototype device. This 3D transmon-type device not only
enables coupling to 3D cavities for microwave probes but also permits DC
transport measurements on the same device, providing useful connections between
transmon properties and critical currents associated with JJ's properties. We
have demonstrated how flux-modulation in cavity frequency and DC critical
current can be correlated under the influence of Fraunhofer pattern of JJs in
an asymmetric SQUID. The correlation analysis was further extended to link the
flux-modulated transmon properties, such as flux-tunability in qubit and cavity
frequencies, with SQUID symmetry analysis based on DC measurements. Our study
paves the way towards integrating novel materials for exploration of new types
of quantum devices for future technology while probing underlying physics in
the composite materials
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Measurements of Natural Carbonate Rare Earth Elements in Femtogram Quantities by Inductive Coupled Plasma Sector Field Mass Spectrometry
A rapid and precise standard-bracketing method has been developed for measuring femtogram quantity rare earth element (REE) levels in natural carbonate samples by inductively coupled plasma sector field mass spectrometry that does not require chemical separation steps. A desolvation nebulization system was used to effectively reduce polyatomic interference and enhance sensitivity. REE/Ca ratios are calculated directly from the intensities of the ion beams of 46Ca, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 153Eu, 160Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 172Yb, and 175Lu using external matrix-matched synthetic standards to correct for instrumental ratio drifting and mass discrimination. A routine measurement time of 3 min is typical for one sample containing 20-40 ppm Ca. Replicate measurements made on natural coral and foraminiferal samples with REE/Ca ratios of 2-242 nmol/mol show that external precisions of 1.9-6.5% (2 RSD) can be achieved with only 10-1000 fg of REEs in 10-20 μg of carbonate. We show that different sources for monthly resolved coral ultratrace REE variability can be distinguished using this method. For natural slow growth-rate carbonate materials, such as sclerosponges, tufa, and speleothems, the high sample throughput, high precision, and high temporal resolution REE records that can be produced with this procedure have the potential to provide valuable time-series records to advance our understanding of paleoclimatic and paleoenvironmental dynamics on different time scales
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