Human Cytomegalovirus IE1 Protein Elicits a Type II Interferon-Like Host Cell Response That Depends on Activated STAT1 but Not Interferon-γ

Human cytomegalovirus (hCMV) is a highly prevalent pathogen that, upon primary infection, establishes life-long persistence in all infected individuals. Acute hCMV infections cause a variety of diseases in humans with developmental or acquired immune deficits. In addition, persistent hCMV infection may contribute to various chronic disease conditions even in immunologically normal people. The pathogenesis of hCMV disease has been frequently linked to inflammatory host immune responses triggered by virus-infected cells. Moreover, hCMV infection activates numerous host genes many of which encode pro-inflammatory proteins. However, little is known about the relative contributions of individual viral gene products to these changes in cellular transcription. We systematically analyzed the effects of the hCMV 72-kDa immediate-early 1 (IE1) protein, a major transcriptional activator and antagonist of type I interferon (IFN) signaling, on the human transcriptome. Following expression under conditions closely mimicking the situation during productive infection, IE1 elicits a global type II IFN-like host cell response. This response is dominated by the selective up-regulation of immune stimulatory genes normally controlled by IFN-γ and includes the synthesis and secretion of pro-inflammatory chemokines. IE1-mediated induction of IFN-stimulated genes strictly depends on tyrosine-phosphorylated signal transducer and activator of transcription 1 (STAT1) and correlates with the nuclear accumulation and sequence-specific binding of STAT1 to IFN-γ-responsive promoters. However, neither synthesis nor secretion of IFN-γ or other IFNs seems to be required for the IE1-dependent effects on cellular gene expression. Our results demonstrate that a single hCMV protein can trigger a pro-inflammatory host transcriptional response via an unexpected STAT1-dependent but IFN-independent mechanism and identify IE1 as a candidate determinant of hCMV pathogenicity

Flexible PV technology development program at IIT Bombay

This paper describes the ongoing flexible PV technology program at the Indian Institute of Technology Bombay. Flexible solar cells are fabricated by depositing amorphous silicon (a-Si) on stainless steel substrate. We have relied on hot-wire CVD technology to deposit films at 110 C, since conventional PECVD processes have proven to be inadequate at that temperature. The primary requirement was a high doping concentration of the p-type and n-type a-Si layers. The efficiency of the single-junction PV cells under simulated AM1.5 global radiation initially was 2.8%, which improved to 4.8% following optimization. Further improvements in efficiency will require development of a technique for low temperature texturing of the transparent conducting oxide film.© IEE

Effect of Segmented Current Collection Contacts Attached to Gas Diffusion Layer in Micro PEM Fuel Cells with Ceramic Flow Field Plates

Proton exchange membrane fuel cells (PEMFCs) are very promising for power stationary applications. One of the key components of fuel cells is the flow field plate through which hydrogen fuel will reach the anode and oxygen reach the cathode. Another function of the flow field plate is the electron collection. Traditionally flow field plates are made of graphite which makes them good for current collection. But graphite is costly and the alternative steel is heavy. Thus with development of MEMS technology it becomes important to have flow field plates made of silicon or ceramics. As silicon and ceramics are not good electrical conductors, electrical contacts have to be attached to the Gas Diffusion Layer (GDL) for taking the power to outside world. This is achieved by attaching contact pads to the GDL area which are not covered by flow plates. A reduction in the power output from the cell is observed with current collection from the GDL. Here we build a three dimensional model for a fuel cell in which current collection is carried out by segmented contacts attached to the GDL and the reasons for drop in performance is studied. Also the current collection contact is segmented in order to increase the power output from the cel

Micro-Solid Oxide Fuel Cell: A multi-fuel approach for portable applications

The impact of oxygen ion transport at the electrolyte-electrode interface of a micro-solid oxide fuel cell using different fuels is investigated. Model validation is performed to verify the results versus the reported values. Furthermore, as the hydrogen-to-carbon ratio decreases, the diffusivity of the oxygen ion increases. This increase in diffusivity is observed because the number of hydrogen atoms available as the reacting species increases in fuels with lower hydrogen-to-carbon ratios. The oxygen ion conductivity and output power density decrease as the hydrogen-to-carbon ratio of the fuels decreases. The reason behind this impact is the formation of a gas-induced ion barrier at the electrode-electrolyte interface by the CO2 molecules formed during the reaction at the interface, thus blocking the flow of oxygen ions. As the oxygen ions become blocked, the output current contribution from the reaction also decreases and thereby affects the overall performance of the micro-solid oxide fuel cell. The experimental verification confirms this because of a significant decrease in the output power density. Furthermore, as per the application in portable devices, the appropriate choice of fuel can be chosen so that the micro-solid oxide fuel cell operates at the maximum power density. (C) 2016 Elsevier Ltd. All rights reserved

Optimisation and fabrication of low-stress, low-temperature silicon oxide cantilevers

Modern lab-on-a-chip systems can benefit from integration of nanoelectromechanical system/microelectromechanical system (NEMS/MEMS) and complementary metal-oxide semiconductor technology with emphasis on low temperature processing. In the present work process, parameters for deposition of silicon oxide (SiO(x)) by inductively coupled plasma chemical vapour deposition (ICPCVD) at low temperature (70 degrees C) are optimised. The sacrificial layer poly(methyl methacrylate) (PMMA) is in-house prepared and optimised. This PMMA sacrificial solution not only gives a low cost wide range of viscosity solutions, but it is also low temperature NEMS process compatible. With optimisations mentioned above, it has been possible to fabricate the whole device without exceeding the thermal budget 100 degrees C. To the best of the authors' knowledge, this is the first report on sub-100 degrees C, surface micromachined SiO(x) cantilevers deposited by ICPCVD and using PMMA as the sacrificial layer for low temperature NEMS applications

Analysis of ambulatory ECG signal

Ambulatory electrocardiogram (ECG) recorders are increasingly in use by people suffering from cardiac abnormalities. However, the ECG signal acquired by the ambulatory recorder is influenced by motion artifacts induced by any body movement activity (BMA). The goal of the paper is to demonstrate that it is possible to determine the BMA from the motion artifacts in the ECG signal itself. The ECG signal during a specific BMA is presumed to be an additive mix or signals due to cardiac activities, motion artifacts induced due to the BMA and sensor noise. We propose to characterize and determine the BMA from the corresponding motion artifact data in the ECG signal itself. The proposed technique is useful for removal of motion artifacts from the ECG signals for ambulatoryN cardiac nionitorin'o

Bandwidth enhancement using gap-coupled hexagonal microstrip antennas in L band

New configurations, involving parasitic gap coupling of identical hexagonal microstrip antennas, are investigated to enhance the bandwidth. A better coupling between the driven and the parasitic patches is realized owing to the straight sides of the hexagonal microstrip antennas. The overall configuration exhibits an enhanced gain due to the increased aperture size. Different gap-coupled configurations, including a novel configuration of the off-axis gap coupling of three hexagonal microstrip antennas, are presented. For this novel configuration, measured bandwidth as large as 101.2 MHz at the center frequency of 1.884 GHz has been obtained, this is almost four times as compared to that of a single hexagonal patch. Both on-axis and off-axis gap coupling of three hexagonal microstrip antennas are explored and the off-axis configuration demonstrates a bandwidth enhancement of approximate to 1.35 times over that of the on-axis configuration. For all the configurations, measured and simulated bandwidths are in close agreement. (c) 2013 Wiley Periodicals, Inc

Design and Fabrication of Bulk Micro-machined, High Resilience, High-Q, High Tilt Angle, Low Driving Voltage, Flexure Beam Micro-mirrors on Mono-crystalline Silicon

We report the design, fabrication and characterization of electrically tunable, bulk micro machined, doubly clamped, circular cross-section flexure based square-plate Metal-On-Oxide, DC bias tension applied, resonant micro-mirrors for different frequencies starting from 1 kilohertz to 172 kilohertz on silicon {100} oriented wafers with high Q factors in the air, that have high resilience. Though silicon shows inherent reflective behavior, the surface quality of the top-deposited metal layer is treatment specific. The sputtered chrome-gold films have good light scattering properties, for precise measurements within 6x6 ROI matrixes for vibrometry and AFM. We introduce novel circular cross-section flexure hinges with the advantages of compact design, 5 fold better precision of rotation compared to similar constant cross-section flexure, lesser stiffness, and beam length and beam width that are less decisive for micro-manufacture. We have fabricated the device, with a double mask, replacing torsion beams with flexure beams. These suspended-in-air-in-trapezoidal-cavity square plate micro-mirrors fabricated on the silicon {100} oriented wafers, are electrically tunable at +/- 30 Volts, with onset of motion at as low as 3 Volts electrical potential, with the largest achieved tilt angle as high as 11 degrees and parabolic capacitance-voltage characteristics, that confirm the motion of the device in a cavity. The motion of these devices was recorded as a Doppler frequency shift. The result shows a slight improvement in mirror surface quality when resonant micro-mirrors are applied with bias tension, that deviates from the results presented in prior art. The micro-mirrors initially show inactivity in motion, which stabilizes later. The exact mechanism responsible for this initial inactivity is not known, we attribute it to the sluggish behavior of joined mechanical elements with large time constants, which slow down the vibrancy