Criticality of tuning in athermal phase transitions

We experimentally address the importance of tuning in athermal phase transitions, which are triggered only by a slowly varying external field acting as tuning parameter. Using higher order statistics of fluctuations, a singular critical instability is detected for the first time in spite of an apparent universal self-similar kinetics over a broad range of driving force. The results as well as the experimental technique are likely to be of significance to many slowly driven non-equilibrium systems from geophysics to material science which display avalanche dynamics.Comment: 5 pages, 4 figure

Benign struma ovarii-a rare monodermal ovarian teratoma-a case report

Struma ovarii is a rare ovarian tumour, first described in 1889 by Boettlin. It is defined by the presence of thyroid tissue comprising of >50% of overall mass. It comprises 1% of all ovarian tumours and 2-5% of all ovarian teratomas. Preoperative diagnosis of struma ovarii is difficult because symptoms, clinical presentation and ultrasound are often similar to that of ovarian carcinoma. Hence most of the patients are diagnosed post operatively. Most cases of strum aovarii are benign and can be treated by excision of the ovary or by unilateral salpingo-oophorectomy. In a small number of cases, there are complications, the most important being the development of malignancy or ascites associated with pleural effusion producing a pseudo-Meigs' syndrome. This is a case of struma ovary presented with features of pseudo-Meig’s syndrome. A 68 year old post-menopausal woman presented with acute abdomen and respiratory distress with an ultrasound diagnosis of ovarian torsion, ascites and pleural effusion and found to have atrial thrombus on evaluation. She had undergone staging laparotomy, TAH+ BSO, omental biopsy and peritoneal fluid cytology. Histopathology revealed predominantly benign and mature colloid filled thyroid follicles of varying sizes lined by cuboidal epithelium surrounded by lymphocytic infiltrate and congested blood vessels, which was suggestive of struma ovary.

A study of vaginal misoprostol tablet versus intra cervical dinoprostone gel for the induction of labour

Background: This was a comparative study conducted to compare the effectiveness of 25 microgram of intravaginal misoprostol with intracervical dinoprostone gel in terms of efficacy of drug, feto-maternal outcome, side effects and complications of drugs.Methods: 400 nulliparas at term, admitted for induction of labor were included in this study. They were randomly selected to receive either intravaginal misoprostol or intracervical dinoprostone gel. Group A (200 women) recieved tablet misoprostol 25 micrograms vaginally 4 hrly to a maximum of 3 doses and Group B (200 women) received dinoprostone gel 0.5mg intracervically 6 hrly to a maximum of 3 doses. Comparison was done in terms of Induction to delivery interval, need for augmentation, LSCS and instrumentation rate, need for NICU admissions and cost effectiveness.Results: The mean induction to delivery interval was less in the misoprostol group than dinoprostone group (12.5 hrs vs. 20 hrs). 78% patients delivered in the first 24 hrs in misoprostol group compared to 52 % patients in dinoprostone group. Group A had a higher success rate (81% vs.76%) and also required less augmentation of labor ( 30% vs. 60%) compared to group B. Need for LSCS was also lower in misoprostol group (11% vs. 16%). Need for instrumentation and incidence of NICU admission was similar in both groups. Misoprostol was more cost effective compared to dinoprostone.Conclusions: The misoprostol group had a shorter induction to delivery interval, more number of deliveries in the first 24 hrs of induction and a reduced need of augmentation of labor with oxytocin. There was no significant difference in the rate of caesarean section, hyper-stimulation syndrome, neonatal and maternal morbidity between the two groups. Thus, misoprosol appears to be safer, cheaper and more efficacious alternative for induction of labor especially for non-fetal indications as compared to dinoprostone gel

Application of Least Square Denoising to Improve ADMM Based Hyperspectral Image Classification

AbstractHyperspectral images contain a huge amount of spatial and spectral information so that, almost any type of Earth feature can be discriminated from any other feature. But, for this classification to be possible, it is to be ensured that there is as less noise as possible in the captured data. Unfortunately, noise is unavoidable in nature and most hyperspectral images need denoising before they can be processed for classification work. In this paper, we are presenting a new approach for denoising hyperspectral images based on Least Square Regularization. Then, the hyperspectral data is classified using Basis Pursuit classifier, a constrained L1 minimization problem. To improve the time requirement for classification, Alternating Direction Method of Multipliers (ADMM) solver is used instead of CVX (convex optimization) solver. The method proposed is compared with other existing denoising methods such as Legendre-Fenchel (LF), Wavelet thresholding and Total Variation (TV). It is observed that the proposed Least Square (LS) denoising method improves classification accuracy much better than other existing denoising techniques. Even with fewer training sets, the proposed denoising technique yields better classification accuracy, thus proving least square denoising to be a powerful denoising technique

Signature of Martensite transformation on conductivity noise in thin films of NiTi shape memory alloys

Slow time-dependent fluctuations, or noise, in the electrical resistance of dc magnetron sputtered thin films of Nickel Titanium shape memory alloys have been measured. Even in equilibrium, the noise was several orders of magnitude larger than that of simple diffusive metallic films, and was found to be non-monotonic around the martensitic transformation regime. The results are discussed in terms of dynamics of structural defects, which also lay foundation to a new noise-based characterization scheme of martensite transformation.Comment: 4 pages, 3 figure

Curvature sensing amphipathic helix in the C-terminus of RTNLB13 is conserved in all endoplasmic reticulum shaping reticulons in Arabidopsis thaliana

The reticulon family of integral membrane proteins are conserved across all eukaryotes and typically localize to the endoplasmic reticulum (ER), where they are involved in generating highly-curved tubules. We recently demonstrated that Reticulon-like protein B13 (RTNLB13) from Arabidopsis thaliana contains a curvature-responsive amphipathic helix (APH) important for the proteins’ ability to induce curvature in the ER membrane, but incapable of generating curvature by itself. We suggested it acts as a feedback element, only folding/binding once a sufficient degree of curvature has been achieved, and stabilizes curvature without disrupting the bilayer. However, it remains unclear whether this is unique to RTNLB13 or is conserved across all reticulons—to date, experimental evidence has only been reported for two reticulons. Here we used biophysical methods to characterize a minimal library of putative APH peptides from across the 21 A. thaliana isoforms. We found that reticulons with the closest evolutionary relationship to RTNLB13 contain curvature-sensing APHs in the same location with sequence conservation. Our data reveal that a more distantly-related branch of reticulons developed a ~ 20-residue linker between the transmembrane domain and APH. This may facilitate functional flexibility as previous studies have linked these isoforms not only to ER remodeling but other cellular activities

Modelling avalanches in martensites

Solids subject to continuous changes of temperature or mechanical load often exhibit discontinuous avalanche-like responses. For instance, avalanche dynamics have been observed during plastic deformation, fracture, domain switching in ferroic materials or martensitic transformations. The statistical analysis of avalanches reveals a very complex scenario with a distinctive lack of characteristic scales. Much effort has been devoted in the last decades to understand the origin and ubiquity of scale-free behaviour in solids and many other systems. This chapter reviews some efforts to understand the characteristics of avalanches in martensites through mathematical modelling.Comment: Chapter in the book "Avalanches in Functional Materials and Geophysics", edited by E. K. H. Salje, A. Saxena, and A. Planes. The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-45612-6_

Signatures of phonon and defect-assisted tunneling in planar metal-hexagonal boron nitride-graphene junctions

Electron tunneling spectroscopy measurements on van der Waals heterostructures consisting of metal and graphene (or graphite) electrodes separated by atomically thin hexagonal boron nitride tunnel barriers are reported. The tunneling conductance, dI/dV, at low voltages is relatively weak, with a strong enhancement reproducibly observed to occur at around |V| ≈ 50 mV. While the weak tunneling at low energies is attributed to the absence of substantial overlap, in momentum space, of the metal and graphene Fermi surfaces, the enhancement at higher energies signals the onset of inelastic processes in which phonons in the heterostructure provide the momentum necessary to link the Fermi surfaces. Pronounced peaks in the second derivative of the tunnel current, d2I/dV2, are observed at voltages where known phonon modes in the tunnel junction have a high density of states. In addition, features in the tunneling conductance attributed to single electron charging of nanometer-scale defects in the boron nitride are also observed in these devices. The small electronic density of states of graphene allows the charging spectra of these defect states to be electrostatically tuned, leading to “Coulomb diamonds” in the tunneling conductance

Fermentation, Isolation, Structure, and antidiabetic activity of NFAT-133 produced by Streptomyces strain PM0324667

Type-2 diabetes is mediated by defects in either insulin secretion or insulin action. In an effort to identify extracts that may stimulate glucose uptake, similar to insulin, a high throughput-screening assay for measuring glucose uptake in skeletal muscle cells was established. During the screening studies to discover novel antidiabetic compounds from microbial resources a Streptomyces strain PM0324667 (MTCC 5543, the Strain accession number at Institute of Microbial Technology, Chandigarh, India), an isolate from arid soil was identified which expressed a secondary metabolite that induced glucose uptake in L6 skeletal muscle cells. By employing bioactivity guided fractionation techniques, a tri-substituted simple aromatic compound with anti-diabetic potential was isolated. It was characterized based on MS and 2D NMR spectral data and identified as NFAT-133 which is a known immunosuppressive agent that inhibits NFAT-dependent transcription in vitro. Our investigations revealed the antidiabetic potential of NFAT-133. The compound induced glucose uptake in differentiated L6 myotubes with an EC50 of 6.3 ± 1.8 μM without activating the peroxisome proliferator-activated receptor-γ. Further, NFAT-133 was also efficacious in vivo in diabetic animals and reduced systemic glucose levels. Thus it is a potential lead compound which can be considered for development as a therapeutic for the treatment of type-2 diabetes. We have reported herewith the isolation of the producer microbe, fermentation, purification, in vitro, and in vivo antidiabetic activity of the compound