Redescription and geographic distribution of Raorchestes shillongensis (Anura: Rhacophoridae) from Meghalaya, Northeast India

Redescription and geographic distribution of Raorchestes shillongensis (Anura: Rhacophoridae) from Meghalaya, Northeast India. Raorchestes shillongensis is a threatened rhacophorid frog endemic to Northeast India. The species is poorly known and systematic information is lacking. We redescribe here the morphology of the species from topotypic material and compare with other Bush Frogs of the region. The locality records from the state of Meghalaya are new. We describe its advertisement call and discuss its phylogenetic position.Redescrição e distribuição geográfca de Raorchestes shillongensis (Anura: Rhacophoridae) de Meghalaya, nordeste da Índia. Raorchestes shillongensis é um anuro racoforídeo ameaçado e endêmico do nordeste da Índia. A espécie é pouco conhecida, não havendo informação sistemática. Redescrevemos aqui a morfologia da espécie a partir de material topotípico e a comparamos com outros racoforídeos da região. O registro da localidade no estado de Meghalaya é novo. Descrevemos ainda seu canto nupcial e discutimos sua posição flogenética

Recrystallization of epitaxial GaN under indentation

We report recrystallization of epitaxial (epi-) GaN(0001) film under indentation.Hardness value is measured close to 10 GPa, using a Berkovich indenter. Pop-in burst in the loading line indicates nucleation of dislocations setting in plastic motion of lattice atoms under stress field for the recrystallization process. Micro-Raman studies are used to identify the recrystallization process. Raman area mapping indicates the crystallized region. Phonon mode corresponding to E2(high) close to 570 cm-1 in the as-grown epi-GaN is redshifted to stress free value close to 567 cm-1 in the indented region. Evolution of A1(TO) and E1(TO) phonon modes are also reported to signify the recrystallization process.Comment: 10 pages, 3 figures

A comparative study on total phenolic content, reducing power and free radical scavenging activity of aerial parts of Barleria prionitis

Context: Barleria prionitis L. (Family Acanthaceae; commonly known as Vajradanti), is an annual shrub, 1–3 feet high, found throughout tropical Asia and in South Africa.Objective: The aim of the present study was to evaluate the antioxidant activity of 50% ethanolic extract of leaf, flower, and stem of B. prionitis by using β carotene bleaching assay, reducing power and free radical scavenging activity (DPPH and hydroxyl radical scavenging activity). Total phenolic content (TPC) was analysed by the Folin–Ciocalteu colorimetric method using gallic acid as standard and expressed as mg/g gallic acid equivalent (GAE).Results: Total phenolic content (TPC) and antioxidant activity (AOA) in B. prionitis leaves were found to be 67.48 mg/g GAE dry plant material and 79.20%. The B. prionitis leaves exhibited strong free radical scavenging activity as evidenced by the low IC50 values in both DPPH (1,1-diphenyl-2-picryl hydrazyl) (336.15 μg/ml) and hydroxyl radical (568.65 μg/ml) methods.Conclusions: The leaf of B. prionitis possesses high phenolic content, potential antioxidant activity, reducing power & radical scavenging activity in comparison to flower and stem.Keywords: Barleria prionitis, total phenolic content, β carotene bleaching assay, reducing power, free radical scavenging activity

Experience in in-situ repair welding of steam turbine shrouds and blades

Cracking have been observed in the turbine shrouds and blades during routine maintenance shut down of power plants owned and operated by Nuclear Power Corporation of India Ltd. In-situ repair of these cracks were carried out using a welding procedure developed indigenously that employed gas tungsten arc welding process and austenitic stainless steel filler wire. Localised post weld heat treatment (PWHT) of the repair welds were also carried out. The turbine components thus repaired have been performing satisfactorily in service for more than three years. This paper presents the development of this welding procedure, its successful execution in the plant and performance of the repair weld in service

V496 Scuti: An Fe II nova with dust shell accompanied by CO emission

We present near-infrared and optical observations of the nova V496 Scuti 2009 covering various phases - pre-maximum, early decline and nebular - during the first 10 months of its discovery followed by limited observations in early part of 2011 April. The spectra follow the evolution of the nova when the lines had strong P Cygni profiles to a phase dominated by prominent emission lines. The notable feature of the near-IR spectra in the early decline phase is the rare presence of first overtone bands of carbon monoxide in emission. Later about 150 days after the peak brightness the IR spectra show clear dust formation in the expanding ejecta. Dust formation in V496 Sct is consistent with the presence of lines of elements with low ionization potentials like Na and Mg in the early spectra and the detection of CO bands in emission. The light curve shows a slow rise to the maximum and a slow decline indicating a prolonged mass loss. This is corroborated by the strengthening of P Cygni profiles during the first 30 days. In the spectra taken close to the optical maximum brightness, the broad and single absorption component seen at the time of discovery is replaced by two sharper components. During the early decline phase two sharp dips that show increasing outflow velocities are seen in the P Cygni absorption components of Fe II and H I lines. The spectra in 2010 March showed the onset of the nebular phase. Several emission lines display saddle-like profiles during the nebular phase. In the nebular stage the observed fluxes of [O III] and H-beta lines are used to estimate the electron number densities and the mass of the ejecta. The optical spectra show that the nova evolved in the P_fe A_o spectral sequence. The physical conditions in the ejecta are estimated. The absolute magnitude and the distance to the nova are estimated to be M_V = -7.0 +/- 0.2 and d = 2.9 +/- 0.3 kpc respectively.Comment: 14 pages, 9 figures and 6 Tables, Accepted for Publication in MNRA

LDL levels and ejection fraction in ischemic stroke patients: a hospital based cross-sectional study

Background: Ischemic stroke is a top contributor to mortality amongst non-infectious diseases. Atherosclerosis is a major risk factor. This study aims to assess LDL levels and ejection fraction in ischemic stroke patients. Methods: This descriptive cross-sectional study was conducted in Government Thoothukudi Medical College from November, 2022 to April, 2023. 35 patients admitted in the neuromedicine ward and diagnosed as acute ischemic stroke were included in the study after informed consent and ethical clearance. Patients with acute neurological deficit and evidence of infarct on diffusion-weighted MRI were included. Patients with no evidence of infarct on DWI, those already on lipid lowering therapy, patients with a history of cerebrovascular disease or transient ischemic attacks were excluded. Blood for lipid profile taken after 8 hours of overnight fasting. Echocardiography done for all patients. Results: Of the 35 patients, 26 (74.28%) were men, mean age was 62.4. 57.14%  ischemic stroke patients had their LDL levels elevated, 28.57% had decreased HDL, 28.57% had total cholesterol levels elevated, and in 14.28% triglycerides was elevated. This study also observed the cardiac status of the patients which showed 29% patients had decreased ejection fraction. Conclusions: This study concluded that most patients had elevated LDL levels which is an independent risk factor of ischemic cerebrovascular disease. LDL levels were also associated with decreased ejection fraction in a significant number of patients. Thereby it can be concluded that elevated LDL cholesterol levels can add to the cardiac risk, potentially contributing to stroke morbidity and mortality

P53 tumor suppressor gene mutations in hepatocellular carcinoma patients in India

Background: Specific mutations of the p53 tumor suppressor gene in hepatocellular carcinoma (HCC) have been reported from several parts of the world, but to the authors' knowledge to date the status of this gene has not been studied in HCC patients in India, where HCC is one of the major cancers and the frequency of chronic hepatitis B virus (HBV) as well as hepatitis C virus (HCV) infection and exposure to dietary aflatoxin B1 is very high. The most frequent mutation of the p53 gene in HCC is an AGGArg to AGTSer missense mutation at codon 249 of exon 7. Methods: Liver biopsy specimens from 21 HCC patients and 10 healthy controls were obtained through surgery or by needle biopsy technique. Phenol-chloroform-extracted DNA specimens were employed for the detection of HBV infection and p53 gene mutations. Nucleotide mutations of exons 4-9 of the p53 gene were analyzed by polymerase chain reaction (PCR), single strand confirmation polymorphism, and direct sequencing. Third-generation sandwich enzyme-linked immunosorbent assay (ELISA) was used for the serologic detection of HBV and HCV infection. Results: Analysis of exons 4-9 of the p53 gene revealed only 3 mutations (3 of 21 specimens, 14.28%; 95% confidence interval, -0.7-29.3), 2 mutations at codon 249 showing G→T transversions, and 1 mutation (4.7%) at codon 250 with a C→T transition. The base substitutions at the third base of codon 249 resulted in a missense mutation leading to a change in amino acid from arginine to serine whereas at codon 250 it caused a change from proline to serine. Dot blot hybridization and PCR for HBV DNA from HCCs revealed 58.8% (10 of 17 specimens) and 90.47% (19 of 21 specimens), positivity, respectively. ELISA for hepatitis B virus surface antigen in serum showed a positivity of 71.42% (15 of 21 specimens), but there was only 40% positivity (8 of 20 specimens) for hepatitis B virus envelope antigen whereas 6 of 17 patients (35.29%) showed the presence of antibodies against hepatitis B virus envelope protein. No patient was found to be positive for the HCV antibody. Conclusions: The very low frequency of p53 mutations and the extremely high frequency of HBV infection (> 90%) in HCC indicate that the mutations in the p53 gene frequently found in HCC reported from different endemic areas of the world may not play a direct role in the development of HCC in India. HBV infection and, possibly, exposure to the dietary aflatoxin B1 appear to play major roles in the molecular pathogenesis of HCC in India

The mechanism of the recrystallization process in epitaxial GaN under dynamic stress field: atomistic origin of planar defect formation

The mechanism of the recrystallization in epitaxial (0001) GaN film, introduced by the indentation technique, is probed by lattice dynamic studies using Raman spectroscopy. The recrystallized region is identified by micro-Raman area mapping. 'Pop-in' bursts in loading lines indicate nucleation of dislocations and climb of dislocations. These processes set in plastic motion of lattice atoms under stress field at the center of indentation for the initiation of the recrystallization process. A planar defect migration mechanism is evolved. A pivotal role of vacancy migration is noted, for the first time, as the rate-limiting factor for the dislocation dynamics initiating the recrystallization process in GaN