Development of CCDs for REXIS on OSIRIS-REx

The Regolith x-ray Imaging Spectrometer (REXIS) is a coded-aperture soft x-ray imaging instrument on the OSIRIS-REx spacecraft to be launched in 2016. The spacecraft will fly to and orbit the near-Earth asteroid Bennu, while REXIS maps the elemental distribution on the asteroid using x-ray fluorescence. The detector consists of a 2×2 array of backilluminated 1k×1k frame transfer CCDs with a flight heritage to Suzaku and Chandra. The back surface has a thin p[superscript +]-doped layer deposited by molecular-beam epitaxy (MBE) for maximum quantum efficiency and energy resolution at low x-ray energies. The CCDs also feature an integrated optical-blocking filter (OBF) to suppress visible and near-infrared light. The OBF is an aluminum film deposited directly on the CCD back surface and is mechanically more robust and less absorptive of x-rays than the conventional free-standing aluminum-coated polymer films. The CCDs have charge transfer inefficiencies of less than 10[superscript -6], and dark current of 1e-/pixel/second at the REXIS operating temperature of –60 °C. The resulting spectral resolution is 115 eV at 2 KeV. The extinction ratio of the filter is ~10[superscript 12] at 625 nm.United States. National Aeronautics and Space Administration. Strategic Astrophysics Technology Program (Grant NNX12AF22G)United States. National Aeronautics and Space Administration (Contract NNG12FD70C)United States. National Aeronautics and Space Administration (IPR NNG12FC01I)United States. National Aeronautics and Space Administration. Strategic Astrophysics Technology Program (IPR NNH12AU04I)United States. Air Force (Contract FA8721-05-C-0002

Blood disorders: Touching of erythrocytes

In general, Erythrocytes may referred to as corpuscle (Red Blood Cells). These erythrocytes will play a significant role in our body. It carries the element round the body and produce dioxide back to lungs. It acquire the element from the lungs then move towards the guts wherever the pure blood is then passed round the body. Erythrocytes covers nearly 1/2 your blood. The mature human erythrocytes is small, Circular, and biconcave; it seems dumbbell-shaped at Look.&nbsp

Development of Pulse Charger for Electric Vehicle Batteries

The issue of slow charging and early battery life deterioration affects emerging new battery technologies. This study suggests a quick pulse charging technique that guards against battery deterioration and provides sustainable operation. The research primarily focuses on newly developed batteries charged from a solar source utilizing a pulsed approach. ANSYS or MATLAB/Simulink are used for the different simulations. The charger circuit comprises the Photovoltaic panel, transformer, a passive element like a capacitor, voltage regulator, and bridge rectifier. An optocoupler, an isolation circuit, and a DSP controller comprise the control circuit. The charger circuit receives power directly from the solar panel, and the duty ratio is configured in the Arduino software, which controls the output voltage

Analgesic efficacy of intra-peritoneal instillation of dexamethasone and bupivacaine versus bupivacaine following laparoscopic cholecystectomy – A randomised, double-blind controlled study

Background and Aims: Laparoscopy is associated with acute pain. We compared the effectiveness of intra-peritoneal dexamethasone with bupivacaine versus bupivacaine in patients undergoing laparoscopic cholecystectomy for postoperative analgesia. Methods: This randomised study was conducted after approval from the institutional ethics committee and 84 patients were randomly allocated into bupivacaine with dexamethasone group (BD) (received 40 mL of 0.25% bupivacaine with 16 mg dexamethasone), and bupivacaine group (BB) (received 40 mL of 0.25% bupivacaine intra-peritoneally). Data analysis was done using R version 4.2.1. The visual analogue scale (VAS) score, total rescue analgesic dose, and time required for the first analgesic between groups were compared using the Wilcoxon rank sum test or t-test appropriately. Results: VAS score was significantly lower in the BD group compared to the BB group until 2 h post-operatively with a mean difference of − 1.0 (95% confidence interval [CI] −1.5, −0.53), P < 0.001. The total rescue analgesic dose consumed was lower in the BD group (60.71 mg [29.80]) compared to the BB group (73.20 mg [11.57]) with a mean difference of − 12.5 mg (95% CI − 22.3, −2.68), P = 0.013. In addition, the time taken for the requirement of the first rescue analgesic was significantly longer in the BD group (417.1 min [276.0]) compared to the BB group (219.4 min [226.1]) with a mean difference of 197.7 (95% CI 75, 320), P = 0.002. Conclusion: Intra-peritoneal instillation of 16 mg dexamethasone with 0.25% bupivacaine in laparoscopic cholecystectomy significantly reduces post-operative pain and requirement of rescue analgesic compared to 0.25% bupivacaine alone

Molecular basis of C-S bond cleavage in the glycyl radical enzyme isethionate sulfite-lyase

Desulfonation of isethionate by the bacterial glycyl radical enzyme (GRE) isethionate sulfite-lyase (IslA) generates sulfite, a substrate for respiration that in turn produces the disease-associated metabolite hydrogen sulfide. Here, we present a 2.7 Å resolution X-ray structure of wild-type IslA from Bilophila wadsworthia with isethionate bound. In comparison with other GREs, alternate positioning of the active site β strands allows for distinct residue positions to contribute to substrate binding. These structural differences, combined with sequence variations, create a highly tailored active site for the binding of the negatively charged isethionate substrate. Through the kinetic analysis of 14 IslA variants and computational analyses, we probe the mechanism by which radical chemistry is used for C-S bond cleavage. This work further elucidates the structural basis of chemistry within the GRE superfamily and will inform structure-based inhibitor design of IsIA and thus of microbial hydrogen sulfide production

A 4-side tileable back illuminated 3D-integrated Mpixel CMOS image sensor

The dominant trend with conventional image sensors is toward scaled-down pixel sizes to increase spatial resolution and decrease chip size and cost. While highly capable chips, these monolithic image sensors devote substantial perimeter area to signal acquisition and control circuitry and trade off pixel complexity for fill factor. For applications such as wide-area persistent surveillance, reconnaissance, and astronomical sky surveys it is desirable to have simultaneous near-real-time imagery with fast, wide field-of-view coverage. Since the fabrication of a complex large-format sensor on a single piece of silicon is cost and yield-prohibitive and is limited to the wafer size, for these applications many smaller-sized image sensors are tiled together to realize very large arrays. Ideally the tiled image sensor has no missing pixels and the pixel pitch is continuous across the seam to minimize loss of information content. CCD-based imagers have been favored for these large mosaic arrays because of their low noise and high sensitivity, but CMOS-based image sensors bring architectural benefits, including electronic shutters, enhanced radiation tolerance, and higher data-rate digital outputs that are more easily scalable to larger arrays. In this report the first back-illuminated, 1 Mpixel, 3D-integrated CMOS image sensor with 8 mum-pitch 3D via connections. The chip employs a conventional pixel layout and requires 500 mum of perimeter silicon to house the support circuitry and protect the array from saw damage. In this paper we present a back-illuminated 1 Mpixel CMOS image sensor tile that includes a 64-channel vertically integrated ADC chip stack, and requires only a few pixels of silicon perimeter to the pixel array. The tile and system connector design support 4-side abuttability and fast burst data rates.United States. Air Force (Contract # FA8721-05-C-0002

Wafer-scale 3D integration of InGaAs image sensors with Si readout circuits

In this work, we modified our wafer-scale 3D integration technique, originally developed for Si, to hybridize InP-based image sensor arrays with Si readout circuits. InGaAs image arrays based on the InGaAs layer grown on InP substrates were fabricated in the same processing line as silicon-on-insulator (SOI) readout circuits. The finished 150-mm-diameter InP wafer was then directly bonded to the SOI wafer and interconnected to the Si readout circuits by 3D vias. A 1024 times 1024 diode array with 8-mum pixel size is demonstrated. This work shows the wafer-scale 3D integration of a compound semiconductor with Si.Defence Advanced Research Projects Agency (Air Force Contract FA8721-05-C-0002

The TESS camera: modeling and measurements with deep depletion devices

The Transiting Exoplanet Survey Satellite, a NASA Explorer-class mission in development, will discover planets around nearby stars, most notably Earth-like planets with potential for follow up characterization. The all-sky survey requires a suite of four wide field-of-view cameras with sensitivity across a broad spectrum. Deep depletion CCDs with a silicon layer of 100 μm thickness serve as the camera detectors, providing enhanced performance in the red wavelengths for sensitivity to cooler stars. The performance of the camera is critical for the mission objectives, with both the optical system and the CCD detectors contributing to the realized image quality. Expectations for image quality are studied using a combination of optical ray tracing in Zemax and simulations in Matlab to account for the interaction of the incoming photons with the 100 μm silicon layer. The simulations include a probabilistic model to determine the depth of travel in the silicon before the photons are converted to photo-electrons, and a Monte Carlo approach to charge diffusion. The charge diffusion model varies with the remaining depth for the photo-electron to traverse and the strength of the intermediate electric field. The simulations are compared with laboratory measurements acquired by an engineering unit camera with the TESS optical design and deep depletion CCDs. In this paper we describe the performance simulations and the corresponding measurements taken with the engineering unit camera, and discuss where the models agree well in predicted trends and where there are differences compared to observations