A current steering positive feedback Improved Recycling Folded Cascode OTA

In the literature, Improved Recycling Folded Cascode (IRFC) Operational Transconductance Amplifier (OTA) is proposed for enhancing the DC gain and the Unity Gain Bandwidth (UGB) of the Recycling Folded Cascode (RFC) OTA. In this paper, an enhanced IRFC (EIRFC) OTA which uses positive feedback at the cascode node is proposed for enhancing the differential mode (DM) gain without changing the unity gain bandwidth (UGB) and lowering the Common mode (CM) gain. For the purpose of comparison, IRFC and EIRFC OTAs are implemented using UMC 90 nm CMOS technology and studied through simulation. From the simulation, it is found that the DM gain and CM gain of EIRFC OTA is higher by 6 dB and lower by 38 dB respectively, compared to that of IRFC OTA for the same power and area. The slew rate of EIRFC OTA is also higher by a factor of 1.5

THERMAL ANALYSIS OF AUTOMOTIVE CYLINDER HEAD MADE BY ALUMINIUM METAL MATRIX COMPOSITE REINFORCED WITH NANO ALUMINA

Metal Matrix Nano Composites (MMNC’s) have been developed to meet the demand for lighter materials with significant improvements in mechanical and physical properties like high strength, excellent wear resistance, good thermal conductivity, low thermal expansion coefficient with particulate reinforcements. Aluminium based nano composites (AA356 – nano Al2O3) with three different percentage (1%, 1.5%, 2.5% Wt) of nano – alumina particulate reinforcement (~40 nm) were fabricated using in-situ stir casting technique. Mechanical properties characterization which strongly depends on microstructural properties of reinforcement revealed that the presence of nano – alumina particulates lead to simultaneous increase in hardness, UTS, wear behaviour. The results revealed that UTS, Hardness, Wear behaviour increases with the increase in the percentage of reinforcement of nano – Al2O3 whereas the thermal conductivity drops with increasing percentage of reinforcement when compared to the base alloy AA356. An attempt is made in the present study to review the opportunities of using such a MMNC developed in automotive brake drum replacing the current system using cast iron

Determination of the chromospheric quiet network element area index and its variation during 2008-2011

Generally it has been considered that the plages and sunspots are the main contributors to the solar irradiance. There are small scale structures on the sun with intermediate magnetic fields that could also contribute to the solar irradiance. It has not yet been quantified how much of these small scale structures contribute to the solar irradiance and how much it varies over the solar cycle. In this paper, we used Ca II K images obtained from the telescope installed at Kodaikanal observatory. We report a method to separate the network elements from the background structure and plage regions. We compute the changes in the network element area index during the minimum phase of solar cycle and part of the ascending phase of cycle 24. The measured area occupied by the network elements is about 30% and plages less than 1% of the solar disk during the observation period from February 2008-2011. During the extended period of minimum activity it is observed that the network element area index decreases by about 7% compared to the area occupied by the network elements in 2008. A long term study of network element area index is required to understand the variations over the solar cycle.Comment: 12 pages, 9 Figures, Accepted for publication in RA

‘Site of contact genotoxicity’ assessment for implants - Potential use of single cell gel electrophoresis in biocompatibility testing of medical devices

Toxicological risk assessment of medical devices requires genotoxicity assessment as per ISO 10993, Part 3, which is designed to address gene mutations, clastogenicity and/or aneugenicity endpoints. ‘Site of contact genotoxicity’ is a potential genotoxic risk especially for medical implants, that is currently not addressed in biocompatibility standards. We therefore performed initial validation study on the use of alkaline single cell gel electrophoresis (comet assay) for detecting ‘site of contact genotoxicity’ of medical devices, using test items made of acrylic implants impregnated with ethyl methanesulphonate (EMS). Comet assay detected increased DNA migration at the site of implantation, but not in the liver. The same implants also failed to show any genotoxicity potentials, when tested on the standard test battery using Salmonella/microsome and chromosome aberration assays. The study suggested that some medical implants can cause ‘site of contact genotoxicity’, without producing systemic genotoxicity. In conclusion, comet assay will add new dimension to safety assessment of medical devices, and this assay can be added to the battery of genetic toxicology tests for evaluating biocompatibility of medical implants

Risk factors for relapse in childhood steroid sensitive nephrotic syndrome

Background: Nephrotic syndrome (NS) generally tends to follow a benign and chronic relapsing course. Relapses are a major problem in children with steroid sensitive NS (SSNS). Objective: To identify the risk factors for frequent relapse (FR) in the first episode childhood SSNS. Methods: This prospective study was conducted in the Government Dharmapuri Medical College Hospital, Tamil Nadu, between July 2013 and January 2016. Children aged 9 months - 12 years with a diagnosis of SSNS (first episode) who came for follow-up for at least 12 months in the pediatric nephrology clinic were included. The enrolled cases were divided into 2 groups: (1) frequent relapser (FR) and (2) infrequent relapser (IFR). 9 factors were studied as possible risk factorsfor relapse. The data collected were analyzed using Chi-square test and Student’s t-test. Results: Of 160 SSNS children, there were 92 (57.5%) cases of IFR and 68 (42.5%) cases of FR. There were 97 males (60.6%) and 63 females (39.4%) with a male to female ratio of 1.5:1. The mean age of presentation was 4.37±2.32 years. The mean time taken to achieve remission during the first episode was 1.94±1.04 weeks. The interval between remission and first relapse was 5.56±4.51 months. Incidence of infection and hypertension was 31.9% and 37.5%, respectively. Risk factors significantly associated with FR were: Time taken to achieveremission during the first episode (>14 days) (p<0.0001), mean duration of interval between remission and first relapse (within 6 months) (p<0.0001), associated infections (p<0.0001) and hypertension (p<0.0001). Age at onset, sex, serum albumin, 24 h urine protein, and azotemia did not influence the FR in our study. Conclusion: More than 14 days to achieve remission during the first episode, relapse within first 6 months, associated infections and hypertension were the factors associated with FRs

Evaluation of a multidisciplinary Tier 3 weight management service for adults with morbid obesity, or obesity and comorbidities, based in primary care

A multidisciplinary Tier 3 weight management service in primary care recruited patients with a body mass index ≥40 kg·m−2, or 30 kg·m−2 with obesity-related co-morbidity to a 1-year programme. A cohort of 230 participants was recruited and evaluated using the National Obesity Observatory Standard Evaluation Framework. The primary outcome was weight loss of at least 5% of baseline weight at 12 months. Diet was assessed using the two-item food frequency questionnaire, activity using the General Practice Physical Activity questionnaire and quality of life using the EuroQol-5D-5L questionnaire. A focus group explored the participants' experiences. Baseline mean weight was 124.4 kg and mean body mass index was 44.1 kg·m−2. A total of 102 participants achieved 5% weight loss at 12 months. The mean weight loss was 10.2 kg among the 117 participants who completed the 12-month programme. Baseline observation carried forward analysis gave a mean weight loss of 5.9 kg at 12 months. Fruit and vegetable intake, activity level and quality of life all improved. The dropout rate was 14.3% at 6 months and 45.1% at 1 year. Focus group participants described high levels of satisfaction. It was possible to deliver a Tier 3 weight management service for obese patients with complex co-morbidity in a primary care setting with a full multidisciplinary team, which obtained good health outcomes compared with existing services

Lithological Discrimination of Anorthosite using ASTER data in Oddanchatram Area, Dindigul district, Tamil Nadu, India

The present study applies with hyperspectral remote sensing techniques to map the lithology of the Oddanchatram anorthosite. The hyperspectral data were subjected to Principal Component Analysis (PCA), Independent Component Analysis (ICA) and Minimum Noise Fraction (MNF), Pixel Purity Index (PPI) and n-Dimensional Visualization for better lithology mapping. The proposed study area has various typical rock types. The PCA, ICA and MNF have been proposed best band combination for effectiveness of lithological mapping such as PCA (R: G: B=2:1:3), MNF (R: G: B=4:3:2) and ICA (R: G: B=3:1:2). The derived lithological map has compared with published geological map from Geological Survey of India and validated with field investigation. Therefore, ASTER data based lithological mapping are fast, cost-effective and more accurate