Design of Double Barrier Ceramic Radio Frequency Vacuum Window

Vacuum windows are an essential part of any radio frequency (RF) system which launches/couples RF power from an atmospheric to a vacuum environment. This paper describes the RF design of a double barrier ceramic coaxial vacuum window. Alumina 99.5% pure is considered as ceramic barrier material while inner and outer conductors are oxygen-free copper. As the initial design approach the thickness, slope, depth of ceramic in the conductor is varied and the performance of the window is studied. The design is optimised to achieve the best insertion loss, return loss response for operating frequency range up to 65MHz

Combined hyperdense gallbladder wall-lumen sign : new computed tomography sign in acute gangrenous cholecystitis

Purpose: The objective of our study was to evaluate the combined hyperdense gallbladder wall-lumen sign on computed tomography (CT) in diagnosing gangrenous cholecystitis. Material and methods: We retrospectively reviewed the unenhanced CT scans of surgically proven cases of acute gangrenous (GCh) and non-gangrenous cholecystitis (nonGCh). Eleven cases of pathologically proven acute gangrenous cholecystitis and 12 consecutive cases of surgically proven acute non-gangrenous cholecystitis that underwent CT at our institute were included in the study so as to have 1 : 1 control. The Hounsfield unit (HU) value of the gallbladder wall and intraluminal bile was measured. Interobserver variability for individual CT findings was also assessed. Results: The gangrenous cholecystitis group had significantly higher HU values of wall and bile (median value of 33 HU vs. 21 HU and median value of 21 HU vs. 8.5 HU, respectively, p < 0.05). The area under the receiver operator characteristic curve for HU lumen was 0.80 (95% CI: 0.62-0.98, p = 0.014) with an ideal cut-off at 31.5 HU, where the sensitivity was 54.5% and specificity was 91.7%. HU lumen has an even better assessment for gangrenous cholecystitis with AUC of its ROC as 0.92 (95% CI: 0.80-1.00, p = 0.001) with an ideal cut-off at 12.5 HU, where the sensitivity was 81.8% and specificity was 91.7%. The combined wall-lumen cut-off is 35 HU with sensitivity of 100% and specificity of 75%. Conclusion: A cut-off CT density value of the gallbladder wall of more than 31.5 HU, intraluminal bile more than 12.5 HU, and combined wall-lumen HU of more than 35 can predict GCh

CSVAG: Optimizing Vertical Handoff Using Hybrid Cuckoo Search and Genetic Algorithm-Based Approaches

One of the primary challenges that wireless technology in the present generation is facing is always best connected (ABC) service. This is possible only when the wireless overlay networks follow a cooperative and coordinated process. Vertical handoff is one such process. Concerning this process, the main challenge is to develop algorithms that take care of optimal connection management with proper resource utilization for uninterrupted mobility. In this paper, we develop a new hybrid cuckoo search (CS) and genetic algorithm (GA) that maximizes the performance of heterogeneous wireless systems in terms of minimizing latency, handover failure probability, and enhancing the throughput. We focus on an optimized simulation framework to demonstrate the advantage of our hybrid model. It can be discerned from the simulation analysis that the proposed hybrid technique increases throughput by 17% and 8% compared to the cuckoo search and genetic algorithms applied individually. The performance of the proposed scheme is promising for applications wherein the handoff mechanisms have to be optimized to control frequent handoffs to further reduce the power consumption of user equipment

Voluntary blood donation in a rural block of Vellore, South India: A knowledge, attitude and practice study

Context: There is a shortage of voluntary blood donors in developing countries which are, therefore, more dependent on replacement donors. Aim: To study the knowledge, attitude, and practices regarding voluntary blood donation in a rural block in Vellore, South India. Settings and Designs: A cross-sectional survey in randomly selected villages of a rural block in Vellore, South India. Materials and Methods: Knowledge, attitude, and practices were assessed using a pilot-tested, semi-structured, interviewer-administered questionnaire on randomly chosen rural adults aged between 18 and 60 years. Results: Of the 104 individuals interviewed, 90% were aware of voluntary blood donation, the main source of this awareness being television. Nearly, two-thirds of the participants felt they would fall sick by donating blood and that women and manual laborers were not capable of blood donation. Among the interviewed, 70.3% were of the opinion that blood can purchased with money. Only 44% were willing to donate blood on a voluntary basis. Perceived weakness and a misconception on the apparent lack of blood were the major reasons for unwillingness to donate blood. There was a significant association between willingness to donate blood and educational status as well as occupation, with the less educated and manual laborers unwilling to donate blood on a voluntary basis (odds ratio [OR] = 3.758, confidence interval [CI] = 1.54–9.156; OR = 5.333, CI = 1.429–19.90, respectively). Conclusions: The study found that although awareness on voluntary blood donation among individuals in the rural community was widespread, hesitancy to donate blood in real life situation was high. Since voluntary unpaid donors are the best candidates for blood donation, community being the best available source, education, and motivation of the community should play a greater role in increasing voluntary blood donation

Intraoperative partial pressure of oxygen measurement to predict flap survival

Introduction: Flap monitoring using partial pressure of oxygen (pO2) is a proven modality. Instruments needed are expensive and are not readily available to a clinician. Here, pO2 of flap has been determined using readily available and cheap methods, and a cut-off value is calculated which helps in predicting flap outcome. Methods and Results: Total 235 points on 84 skin flaps were studied. Capillary blood was collected from flap and fingertip using 1-ml syringes after at least 30 min of flap inset, and pO2 analysed using blood gas analyser. Fall/change of pO2 (difference of mean of pO2 [diff-pO2]) was also calculated by subtracting the flap pO2 from the finger pO2. Flap was monitored clinically in post-operative period and divided into two groups depending on its survival with Group 1 – dead points and Group 2 – alive points. pO2 and diff-pO2 amongst both the groups were compared and found to be statistically different (P = 0.0001). Cut-off value calculated for pO2 was found to be 68.503 mmHg of flap pO2 compared from finger pO2 was calculated as a cut-off with sensitivity of 94.12 and specificity of 79.60%. Conclusions: Flap areas having intra-operative pO2 value 68.5 mmHg, chances of those points getting necrosed in post-operative period are high

Detailed study of reactively sputtered ScN thin films at room temperature

To contemplate an alternative approach for the minimization of diffusion at high temperature, present findings impart viability of room-temperature deposited reactively sputtered ScN thin films. The adopted route endows precise control over the flow for a methodical structural phase evolution from Sc --> ScN and probe the correlated physical aspects of the highly textured ScN samples. In the nitrided regime i.e. at $R_{N_2}$= 2.5–100% flow, incorporation of unintentional oxygen defects was evidenced from surface sensitive soft x-ray absorption spectroscopy study, though less compared to their metal ( $R_{N_2}$ = 0%) and interstitial ($R_{N_2}$ = 1.6%) counterparts, due to higher Gibbs free energy for Sc-O-N formation with no trace of ligand field splitting around the O K-edge spectra. To eradicate the skepticism of appearance of N K-edge (401.6 eV) and Sc L-edge (402.2 eV) absorption spectra adjacent to each other, the first-ever Sc K-edge study has been adopted to validate complementary insight on the metrical parameters of the Sc-N system. Optical bandgaps of the polycrystalline ScN thin film samples were found to vary between 2.25 and 2.62 eV as obtained from the UV–vis spectroscopy, whereas, the nano-indentation hardness and modulus of the as-deposited samples lie between 15–34 GPa and 152–476 GPa, respectively following a linearly increasing trend of resistance to plastic deformations with an exception at 34 GPa in case of $R_{N_2}$ = 5% sample. Besides, contrary to other early 3d transition metal nitrides (TiN, VN, CrN), a comprehensive comparison of noticeably large homogeneity range in Sc-N has been outlined to apprehend the minuscule lattice expansion over the large $R_{N_2}$ realm