Design and Development of Compact Conformal Microstrip Antenna at S-Band

A compact microstrip antenna at S-Band is described in this work. This paper presents the theoretical and experimental investigations on conformal 90° Sectoral circular microstrip antenna using shorting wall. The performance of antenna characteristics is obtained using FEM based HFSS software and the computed results are verified by measurement. Here, microstrip antenna is loaded with shorting wall to achieve frequency reduction of about 75 per cent. The antenna characteristics were studied with radome surrounded by metallic ring. The radiation characteristics of antenna mounted on vehicle body is carried out. The antenna has moderate gain and wider coverage in roll plane as well as azimuth plane and may be used as small, compact antenna for onboard telemetry applications

Atomic absorbers for controlling pulse propagation in resonators

We consider pulse propagation through a Fabry-Perot cavity with silver mirrors that contain macroscopic samples of resonant absorbers. We show that the pulse velocity can be tuned from subluminal to superluminal in a strongly coupled atom-cavity system. We delineate the effects of the interplay of cavity and absorbers. We demonstrate the saturation effects of pulse advancement with increasing mirror thickness and atomic damping

SARAS 2: A Spectral Radiometer for probing Cosmic Dawn and the Epoch of Reionization through detection of the global 21 cm signal

The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts $z \sim 6-30$, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted to be extremely weak, of wide fractional bandwidth, and lies in a frequency range that is dominated by Galactic and Extragalactic foregrounds as well as Radio Frequency Interference, detection of the signal is a daunting task. Critical to the experiment is the manner in which the sky signal is represented through the instrument. It is of utmost importance to design a system whose spectral bandpass and additive spurious can be well calibrated and any calibration residual does not mimic the signal. SARAS is an ongoing experiment that aims to detect the global 21 cm signal. Here we present the design philosophy of the SARAS 2 system and discuss its performance and limitations based on laboratory and field measurements. Laboratory tests with the antenna replaced with a variety of terminations, including a network model for the antenna impedance, show that the gain calibration and modeling of internal additives leave no residuals with Fourier amplitudes exceeding 2~mK, or residual Gaussians of 25 MHz width with amplitudes exceeding 2~mK. Thus, even accounting for reflection and radiation efficiency losses in the antenna, the SARAS~2 system is capable of detection of complex 21-cm profiles at the level predicted by currently favoured models for thermal baryon evolution.Comment: 44 pages, 17 figures; comments and suggestions are welcom

“ Thioureidopeptide”: Novel Synthon for the Synthesis of N, N′, N″-Trisubstituted Guanidinopeptide Mimics

The synthesis of N α-protected N,N′,N″-trisubstituted guanidinopeptide mimic molecules suitably decorated in peptide backbone has been delineated in one pot employing HgCl2 as a desulphurizing agent. Chiral N α -protected thioureidopeptide esters were employed as synthons for the synthesis of title molecules. The protocol is simple and the reaction conditions employed were mild, amenable to the amino acid chemistry

Management of Acute Liver Failure: A Pediatric Perspective

This article is made available for unrestricted research re-use and secondary analysis in any form or be any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemicPurpose of review: Pediatric acute liver failure is a rare, complex, rapidly progressing, and life-threatening illness. Majority of pediatric acute liver failures have unknown etiology. This review intends to discuss the current literature on the challenging aspects of management of acute liver failure. Recent findings: Collaborative multidisciplinary approach for management of patients with pediatric acute liver failure with upfront involvement of transplant hepatologist and critical care specialists can improve outcomes of this fatal disease. Extensive but systematic diagnostic evaluation can help to identify etiology and guide management. Early referral to a transplant center with prompt liver transplant, if indicated, can lead to improved survival in these patients. Summary: Prompt identification and aggressive management of pediatric acute liver failure and related comorbidities can lead to increased transplant-free survival and improved post-transplant outcomes, thus decreasing mortality and morbidity associated with this potential fatal condition

The use of hyperbaric oxygen therapy in actinomycotic osteomyelitis associated florid cemento osseous dysplasia: report of a familial case.

Florid Cemento-Osseous Dysplasia (FCOD) is a well recognized fibro-osseous disease of the jaws commonly seen in the middle aged African women, although it may occur in the Caucasians and Asians. There is a reported incidence of less than 2% in the Indian population. The clinical and the radiographic features of FCOD may overlap with features of chronic diffuse scle-rosing osteomyelitis, which makes diagnosis of the disease difficult in symptomatic cases. Moreover the jaws may be susceptible to osteomyelitis, which may mask the underlying FCOD in some cases. The case reported here is that of a 56 year old Indian female patient with long standing FCOD invol-ving the maxilla and the mandible, who was asymptomatic till all her teeth were extracted for fabrica-tion of complete dentures. The patient experienced symptoms of pain, swelling and purulent discharge soon after the use of dentures and was treated by surgical removal of the affected bone. The same symptoms recurred in other areas of the jaw over a period of time and these areas were treated surgica-lly. The patient subsequently presented with pain in the mandibular left posterior region of ten days duration, and was diagnosed as FCOD with superimposed Actinomycotic Osteomyelitis based on his-topathology and Gram’s stain, and was treated by surgical removal of the affected bone followed by hyperbaric oxygen therapy (HBO). The radiograph of the surgical site showed good amount of bone regeneration within six months of HBO therapy without recurrence of the FCOD in the same area till date

An Efficient Score level Multimodal Biometric System using ECG and Fingerprint

Biometric system is a security system that uses human’s unique traits to identify and authenticate the user. Biometrics refers to biological traits of a human that are often categorized as physiological traits like fingerprint, iris, face and behavioral characteristics like signature style, voice and typing rhythm. The Biological signals like Electrocardiography (ECG), Electromyography(EMG), and Electroencephalography (EEG) have not been explored to biometric applications as their scope was limited to medical applications only. Recent survey suggests that these biological signals can be explored as a part of the biometric application. The main objective of this paper is to explore the possibility of using the ECG as a part of multimodal biometric. ECG has lower accuracy but fusing it with a traditional biometric like fingerprint yields a higher accuracy rate and it is really difficult to spoof the system. The proposed multimodal biometrics system has an accuracy of 98% with the false acceptance rate of 2% and almost 0% of false rejection rate

The role of mast cells on angiogenesis in oral squamous cell carcinoma

Objective: Angiogenesis or neovascularization has long been known to aid in progression and metastasis of malignant tumors. Tumor angiogenesis is a complex event mediated by angiogenic factors released from cancer cells and or by host immune cells. Mast cells may induce tumor progression and potentiate metastasis by stimulating angiogenesis. The purpose of the present study was to validate topographic distribution of micro vessel density (MVD) and mast cell density (MCD) and help to elucidate the possible role of mast cells in tumor angiogenesis and correlating this with advanced disease parameters. Study Design: MVD and MCD were investigated in tumor specimens from 30 patients diagnosed with different histologic grades of oral squamous cell carcinoma (OSCC). Intratumor vessels were stained with collagen Type IV antibody and mast cells with Toluidine blue before being measured by light microscopy. Results: There was a significant correlation between MVD and disease progression and number of blood vessels increased from well to poorly differentiated OSCC where as MCD decreased. Conclusions: These findings suggest that angiogenesis indeed occur in OSCC and might be used as an index to inflect the aggression of the disease however mast cells make up only a part of complex process of angiogenesis along with other factors secreted by tumor. © Medicina Oral S. L

Fresnel zone plate telescopes for X-ray imaging II: numerical simulations with parallel and diverging beams

We present the results of simulations of shadows cast by a zone plate telescope which may have one to four pairs of zone plates. From the shadows we reconstruct the images under various circumstances. We discuss physical basis of the resolution of the telescope and demonstrate this by our simulations. We allow the source to be at a finite distance (diverging beam) as well as at an infinite distance (parallel beam) and show that the resolution is worsened when the source is nearby. By reconstructing the zone plates in a way that both the zone plates subtend the same solid angles at the source, we obtain back high resolution even for sources at a finite distance. We present simulated results for the observation of the galactic center and show that the sources of varying intensities may be reconstructed with accuracy. Results of these simulations would be of immense use in interpreting the X-ray images from recently launched CORONAS-PHOTON satellite.Comment: 17 pages, 36 figures, Published in Experimental Astronom