Iteratively reweighted ℓ1-ℓ2 norm minimization using wavelets in inverse scattering.

Recently, many techniques have been employed to solve inverse scattering problems by exploiting the sparsity of the scatterer in the wavelet basis. In this paper, we propose an iteratively reweighted $ {\ell _1} $ norm regularization scheme within the settings of the Born iterative method (BIM) to effectively leverage the sparsity of the wavelet coefficients. This "iteratively reweighted $ {\ell _1} $ minimization" method is then used along with $ {\ell _2} $ norm minimization in order to achieve solutions that are not over-smoothened at the discontinuities. The proposed method is an expansion of a well-known joint $ {\ell _1} {-} {\ell _2} $ norm minimization technique. The advantage offered by the algorithm is that the reconstruction is now independent of the initial choice of weights. This technique accounts for the fact that sparsity is concentrated more in the detail wavelet coefficients rather than their coarse counterpart. The effectiveness of the method is demonstrated using several 2D inverse scattering examples by employing it in each iteration of the BIM.

Iteratively reweighted ℓ1-ℓ2 norm minimization using wavelets in inverse scattering: publisher's note.

This publisher's note corrects the author list in J. Opt. Soc. Am. A37, 680 (2020).JOAOD60740-323210.1364/JOSAA.381365.

Evaluation of near infrared spectroscopy as screening tool for detecting intracranial hematomas in patients with traumatic brain injury.

BACKGROUND: Traumatic Brain Injury (TBI) is one of the most common surgical emergencies in service hospitals of India. Computed tomography (CT) has been a consistent and reliable technique for detecting intracranial hemorrhages but is limited by its non-availability in most service hospitals. Therefore the need for a cheaper, portable and easily available option required to be explored. The aim of this study was to determine the sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of Near Infra Red Spectroscopy (NIRS) against the gold standard of NCCT head. METHODS: An observational, prospective study was conducted in 100 patients of closed head injury, attending the emergency department or surgical OPD of a service zonal hospital with NIRS. All these patients were subsequently subjected to NCCT head. Sensitivity, specificity, and positive and negative predictive values of NIRS were calculated. The study was conducted from Oct 2010 to Jul 2012. RESULTS: All the 100 patients were evaluated with NIRS and subsequently subjected to NCCT head. The results were compiled and statistical analysis of the same was conducted. The data revealed a sensitivity of 58.46%, a specificity of 42.86%, a positive predictive value of 65.52% and a negative predictive value of 35.71%. CONCLUSION: Near Infra Red Spectroscopy (NIRS) is a good screening tool for prediction of intra cerebral haemorrhage in the field and even intensive care units. This was the first study of its kind in the Indian subcontinent and the results suggest that NIRS is a good device to predict intracranial subdural and epidural haematomas. It is however not superior to computer tomography and magnetic resonance imaging.

Hydrogen peroxide test for intraoperative bile leak detection.

BACKGROUND: Bile leakage (BL) is a common complication following liver surgery, ranging from 3 to 27% in different series. To reduce the incidence of post-operative BL various BL tests have been applied since ages, but no method is foolproof and every method has their own limitations. In this study we used a relatively simpler technique to detect the BL intra-operatively. Topical application of 1.5% diluted hydrogen peroxide (H2O2) was used to detect the BL from cut surface of liver and we compared this with conventional saline method to know the efficacy. METHODS: A total of 31 patients included all patients who underwent liver resection and donor hepatectomies as part of Living Donor Liver Transplantation. After complete liver resection, the conventional saline test followed by topical diluted 1.5% H2O2 test was performed on all. RESULTS: A BL was demonstrated in 11 patients (35.48%) by the conventional saline method and in 19 patients (61.29%) by H2O2 method. Statistically compared by Wilcoxon signed-rank test showed significant difference (P = 0.014) for minor liver resections group and (P = 0.002) for major liver resections group. CONCLUSION: The topical application of H2O2 is a simple and effective method of detection of BL from cut surface of liver. It is an easy, non-invasive, cheap, less time consuming, reproducible, and sensitive technique with no obvious disadvantages.

Electromagnetic cloaking in convex and concave media with surface modelled as a parameterised function.

The onset of transformation optics has opened avenues for designing of a plenitude of applications related to propagation of electromagnetic waves in anisotropic media. In this paper, an algorithm is proposed using a coordinate transformation and a piecewise function for the purpose of designing a three dimensional cloak having an arbitrary geometry which could be convex or non-convex in nature. The surfaces of the cloak as well as of the body under consideration are assumed to be conformal to each other. For an arbitrary geometry, the coordinate system needed to model the surface can be a non-orthogonal system. For the purpose of verification of the algorithm, a ray tracing process is carried out for an ellipsoid as well as for a concave surface having axial symmetry. In order to solve the Hamiltonian equation for the purpose of ray tracing, the process of finding the derivatives analytically, for an arbitrary geometry as considered here, becomes very cumbersome. Here, a numerical method is described which provides a better approximation to the partial derivatives than the conventional finite difference approach based on forward differences.

Dimorphism and hydrocarbon metabolism in Yarrowia lipolytica var. indica.

Yarrowia lipolytica is able to metabolize high Mr hydrophobic natural compounds such as fatty acids and hydrocarbons. Characteristically, strains of Y. lipolytica can grow as populations with variable proportions of yeast and filamentous forms. In the present study, we describe the dimorphic characteristics of a variant designated as Y. lipolytica var. indica isolated from petroleum contaminated sea water and the effect of cell morphology on hydrocarbon metabolism. The variant behaved as a yeast monomorphic strain, under conditions at which terrestrial Y. lipolytica strain W29 and its derived strains, grow as almost uniform populations of mycelial cells. Using organic nitrogen sources and N-acetylglucosamine as carbon source, var. indica was able to form mycelial cells, the proportion of which increased when incubated under semi-anaerobic conditions. The cell surface characteristics of var. indica and W29 were found to be different with respect to contact angle and percent hydrophobicity. For instance, percent hydrophobicity of var. indica was 89.93 ± 1.95 while that of W29 was 70.78 ± 1.1. Furthermore, while all tested strains metabolize hydrocarbons, only var. indica was able to use it as a carbon source. Yeast cells of var. indica metabolized hexadecane with higher efficiency than the mycelial form, whereas the mycelial form of the terrestrial strain metabolized the hydrocarbon more efficiently, as occurred with the mycelial monomorphic mutant AC11, compared to the yeast monomorphic mutant AC1.

Biodegradation of tributyl phosphate using Klebsiella pneumoniae sp. S3.

Tributyl phosphate (TBP) has enormous applications in the field of extraction, fuel reprocessing, as defoamers and/or plasticizers. Excessive usage of this organophosphorus compound, poses an environmental threat. The present study deals with microbial degradation of TBP using Klebsiella pneumoniae S3 isolated from the soil. Diauxic growth curve pattern explains a preferential utilization of TBP. The strain S3 was able to biotransform TBP (1,000 mg L⁻¹) to dibutyl phosphate within 48 h and showed higher tolerance towards TBP up to 17.0 g L⁻¹. Toxicity of the parent as well as degraded product was assessed using comet assay. Generation of reactive oxygen species elaborates the oxidative stress imposed upon the bacterial strain by TBP. The antioxidant defense mechanism was studied using various biomarkers namely catalase, glutathione-S-transferase, and superoxide dismutase. The present study describes a faster and eco-friendly alternative for disposal of TBP.

Role of p120 Ras-GAP in directed cell movement.

We have used cell lines deficient in p120 Ras GTPase activating protein (Ras-GAP) to investigate the roles of Ras-GAP and the associated p190 Rho-GAP (p190) in cell polarity and cell migration. Cell wounding assays showed that Ras-GAP-deficient cells were incapable of establishing complete cell polarity and migration into the wound. Stimulation of mutant cells with growth factor rescued defects in cell spreading, Golgi apparatus fragmentation, and polarized vesicular transport and partially rescued migration in a Ras-dependent manner. However, for directional movement, the turnover of stress fibers and focal adhesions to produce an elongate morphology was dependent on the constitutive association between Ras-GAP and p190, independent of Ras regulation. Disruption of the phosphotyrosine-mediated Ras-GAP/p190 complex by microinjecting synthetic peptides derived from p190 sequences in wild-type cells caused a suppression of actin filament reorientation and migration. From these observations we suggest that although Ras-GAP is not directly required for motility per se, it is important for cell polarization by regulating actin stress fiber and focal adhesion reorientation when complexed with 190. This observation suggests a specific function for Ras-GAP separate from Ras regulation in cell motility.

Opportunistic parasitic infections in HIV/AIDS patients presenting with diarrhoea by the level of immunesuppression.

BACKGROUND & OBJECTIVE: Enteric parasites are major cause of diarrhoea in HIV infected individuals. The present study was undertaken to detect enteric parasites in HIV infected patients with diarrhoea at different levels of immunity. METHODS: The study was carried out at National AIDS Research Institute, Pune, India, between March 2002 and March 2007 among consecutively enrolled 137 HIV infected patients presenting with diarrhoea. Stool samples were collected and examined for enteric parasites by microscopy and special staining methods. CD4 cell counts were estimated using the FACS count system. RESULTS: Intestinal parasitic pathogens were detected in 35 per cent patients, and the major pathogens included Cryptosporidium parvum (12%) the most common followed by Isospora belli (8%), Entamoeba histolytica/Enatmoeba dispar (7%), Microsporidia (1%) and Cyclospora (0.7%). In HIV infected patients with CD4 count < 200 cells/microl, C. parvum was the most commonly observed (54%) pathogen. Proportion of opportunistic pathogens in patients with CD4 count <200 cells/microl was significantly higher as compared with other two groups of patients with CD4 count >200-499 and >or= 500 cells/microl (P=0.001, P=0.016) respectively. INTERPRETATION & CONCLUSION: Parasitic infections were detected in 35 per cent HIV infected patients and low CD4 count was significantly associated with opportunistic infection. Detection of aetiologic pathogens might help clinicians decide appropriate management strategies.

Design of the 1.5 MW, 30-96 MHz ultra-wideband 3 dB high power hybrid coupler for Ion Cyclotron Resonance Frequency (ICRF) heating in fusion grade reactor.

Design and developmental procedure of strip-line based 1.5 MW, 30-96 MHz, ultra-wideband high power 3 dB hybrid coupler has been presented and its applicability in ion cyclotron resonance heating (ICRH) in tokamak is discussed. For the high power handling capability, spacing between conductors and ground need to very high. Hence other structural parameters like strip-width, strip thickness coupling gap, and junction also become large which can be gone upto optimum limit where various constrains like fabrication tolerance, discontinuities, and excitation of higher TE and TM modes become prominent and significantly deteriorates the desired parameters of the coupled lines system. In designed hybrid coupler, two 8.34 dB coupled lines are connected in tandem to get desired coupling of 3 dB and air is used as dielectric. The spacing between ground and conductors are taken as 0.164 m for 1.5 MW power handling capability. To have the desired spacing, each of 8.34 dB segments are designed with inner dimension of 3.6 × 1.0 × 40 cm where constraints have been significantly realized, compensated, and applied in designing of 1.5 MW hybrid coupler and presented in paper.

The effect of laparoscopic sleeve gastrectomy (LSG) on glycemic control in morbidly obese patients.

INTRODUCTION: Bariatric procedures have become popular in treating not only the morbid obesity but also the metabolic derangements. Sleeve Gastrectomy has recently become popular as a standalone procedure and its usefulness as a metabolic procedure especially glycemic control is still under investigation. One of the most commonly used measure of insulin resistance is statistically derived 'Homeostatic model assessment of insulin resistance (HOMA-IR). AIM: The effect of Laparoscopic Sleeve Gastrectomy (LSG) on clinical and measurable change in glycemic control as seen by reduction of insulin resistance ie HOMA-IR levels in morbidly obese patients. MATERIAL AND METHODS: All the patients with BMI ≥35 kg/m(2) with co morbidities and BMI ≥40 kg/m(2) even without co morbidities were included in the study. The period of the study was from Feb 2013 to Sep 2014. Fasting (FBS), post prandial blood sugar (PPBS) and Insulin levels were checked before the surgery, 1month and 3 month after the surgery. We also recorded BMI and diabetic status. HOMA-IR was calculated and trends were recorded. STATISTICAL ANALYSIS: Statistical analysis was carried out using SPSS 16.0. RESULTS: Out of 28 patients 8 were males and 20 were females. The mean age was 43 yrs. 11 (39%) patients were diabetic and mean BMI was 44 kg/m(2) and a range of (35-61.3) kg/m(2). 11 patients had BMI > 45 kg/m(2). The HOMA-IR values decreased significantly after the surgery both in diabetics and non diabetics. CONCLUSION: LSG results in improvement in glycemic control in both diabetics and non diabetics.

Detection of mutations in mtrR gene in quinolone resistant strains of N. gonorrhoeae isolated from India.

BACKGROUND AND OBJECTIVES: Emergence of multi-drug resistant Neisseria gonorrhoeae resulting from new genetic mutation is a serious threat in controlling gonorrhea. This study was undertaken to identify and characterise mutations in the mtrR genes in N.gonorrhoeae isolates resistant to six different antibiotics in the quinolone group. MATERIALS AND METHODS: The Minimum inhibitory concentrations (MIC) of five quinolones for 64 N.gonorrhoeae isolates isolated during Jan 2007-Jun 2009 were determined by E-test method. Mutations in MtrR loci were examined by deoxyribonucleic acid (DNA) sequencing. RESULTS: The proportion of N.gonorrhoeae strains resistant to anti-microbials was 98.4% for norfloxacin and ofloxacin, 96.8% for enoxacin and ciprofloxacin, 95.3% for lomefloxacin. Thirty-one (48.4%) strains showed mutation (single/multiple) in mtrR gene. Ten different mutations were observed and Gly-45 → Asp, Tyr-105 → His being the most common observed mutation. CONCLUSION: This is the first report from India on quinolone resistance mutations in MtrRCDE efflux system in N.gonorrhoeae. In conclusion, the high level of resistance to quinolone and single or multiple mutations in mtrR gene could limit the drug choices for gonorrhoea.

A population-based screening program for early detection of common cancers among women in India - methodology and interim results.

BACKGROUND: Cancers of the uterine cervix, breast, and oral cavity accounted for 134,420, 115,251, and 24,375 cases, respectively, and were responsible for 52.8% of the total cancers among women in India in 2008. AIM: The major objectives were to create awareness regarding common cancers among women, to detect pre-cancers of the uterine cervix and oral cavity, and early cancers of the breast, uterine cervix, and oral cavity, by conducting screening with simple, low-cost technology, within the community, and to facilitate confirmation of diagnosis among the screen positives and treatment and follow-up among the diagnosed cases. SETTINGS AND METHODS: This is a community-based screening program for early detection of breast, uterine cervix, and oral cancers, being implemented among the socioeconomically disadvantaged women in Mumbai, India. The process involves selection of clusters, household surveys, health education, and screening the eligible women for breast, uterine cervix, and oral cancers, by primary healthcare workers, at a temporarily set-up clinic within the community. The program is planned to cover a 125,000 disadvantaged population in five years. RESULTS: Twenty-one thousand and fifteen people, with 4009 eligible women, have been covered to date. The compliance for screening for breast, cervix, and oral cavity has been 85, 70, and 88% and the screen positivity rates are 3.9, 14.9, and 3.9%, respectively. Twenty-seven oral pre-cancers, 25 cervix pre-cancers, one invasive cancer of the breast, two of the cervix, and one oral cavity cancer have been diagnosed among the screened women and all of them have complied with the treatment. CONCLUSIONS: The program is raising awareness about the common cancers and harms of tobacco among the disadvantaged women population in Mumbai. It is also helping in detecting pre-cancers and cancers among asymptomatic women and is assisting them in receiving treatment.

Benign paravertebral ancient neurilemmoma in a young adult: a rare occurrence.

Neurilemmoma is a benign neurogenic tumour arising from Schwann cells of the peripheral nerve sheath, which is commonly seen in women in the 5th decade. It rarely arises in the retroperitoneum, being more common in the head and neck region and extremities. Ancient variety of schwannoma is a long-standing tumour, is seen in the middle age and elderly age groups, and is associated with secondary degenerative changes. Herein, we report a case of benign retroperitoneal paravertebral ancient neurilemmoma occurring in a young male adult.

Clinical significance of serum and cerebro spinal fluid bilirubin indices in neonatal jaundice.

To assess the value of unbound bilirubin (UB) and saturation index (SI) in serum and CSF as indicators of Kernicterus, we studied 50 icteric neonates (serum indirect bilibrubin (IB) greater than or equal to 7 mg/dl) and 20 controls (IB less than 7 mg/dl) during the first week of life. Serum and CSF were obtained simultaneously in all neonates. Of 36 neonates with IB greater than 12 mg/dl 19 had evidence of kernicterus. UB was estimated by Sephadex gel filtration and SI by salicylate displacement technique. Positive correlation (r = +0.85) was obtained between serum and CSF UB levels. There was a significant difference (p less than 0.05) between mean serum and CSF UB levels in kernicterus and non-kernicterus neonates (kernicterus serum UB = 0.71 +/- 0.22) mg/dl, CSF UB = 0.16 +/- 0.06 mg/dl: non-kernicteric serum UB = 0.40 +/- 0.10 mg/dl, CSF UB = 0.10 +/- 0.03 mg/dl). A critical serum UB level 0.5 mg/dl and a danger zone of CSF UB (0.1 to 0.15 mg/dl) was observed in presence of kernicterus. Neonates with kernicterus and 30% non-kernicteric had serum SI greater than or equal to 8. Mean values of serum and CSF SI were comparable in all neonates. The serum and CSF UB and SI, and the mean percentage cross over of UB from serum to CSF when statistically compared were not significantly influenced by risk factors.

Design and development of ultra-wideband 3 dB hybrid coupler for Ion cyclotron resonance frequency heating in tokamak.

Design and development of a high power ultra-wideband, 3 dB tandem hybrid coupler is presented and its application in ICRF heating of the tokamak is discussed. In order to achieve the desired frequency band of 38-112 MHz and 200 kW power handling capability, the 3 dB hybrid coupler is developed using two 3-element 8.34 ± 0.2 dB coupled lines sections in tandem. In multi-element coupled lines, junctions are employed for the joining of coupled elements that produce the undesirable reactance called junction discontinuity effect. The effect becomes prominent in the high power multi-element coupled lines for high frequency (HF) and very high frequency(VHF) applications because of larger structural dimensions. Junction discontinuity effect significantly deteriorates coupling and output performance from the theoretical predictions. For the analysis of junction discontinuity effect and its compensation, a theoretical approach has been developed and generalized for n-element coupled lines section. The theory has been applied in the development of the 3 dB hybrid coupler. The fabricated hybrid coupler has been experimentally characterized using vector network analyzer and obtained results are found in good agreement with developed theory.

Community-based tobacco cessation program among women in Mumbai, India.

BACKGROUND: Globally tobacco epidemic kills nearly six million people annually. Consumption of tobacco products is on the rise in low- and middle-income countries. Tobacco is addictive; hence, tobacco users need support in quitting. AIMS: Providing tobacco cessation services to women in community enabling them to quit tobacco, identifying factors associated with quitting and documenting the processes involved to establish a replicable "model tobacco cessation program." SETTINGS AND DESIGN: This is a community based tobacco cessation program of one year duration conducted among women in a low socioeconomic area of Mumbai, India. SUBJECTS AND METHODS: It involved three interventions conducted at three months interval, comprised of health education, games and counseling sessions and a post intervention follow-up. STATISTICAL ANALYSIS: Uni and multivariate analysis was performed to find out association of various factors with quitting tobacco. RESULTS: The average compliance in three intervention rounds was 95.2%. The mean age at initiation of tobacco was 17.3 years. Tobacco use among family members and in the community was primary reasons for initiation and addiction to tobacco was an important factor for continuation, whereas health education and counseling seemed to be largely responsible for quitting. The quit rate at the end of the programme was 33.5%. Multivariate logistic regression analysis found that women in higher age groups and women consuming tobacco at multiple locations are less likely to quit tobacco. CONCLUSIONS: Changing cultural norms associated with smokeless tobacco, strict implementation of antitobacco laws in the community and work places and providing cessation support are important measures in preventing initiation and continuation of tobacco use among women in India.