Gate controlled large resistance switching driven by charge density wave in 1T-TaS2/2H-MoS2 heterojunction

1T-TaS2 is a layered material that exhibits charge density wave (CDW) induced distinct electrical resistivity phases and has attracted a lot of attention for interesting device applications. However, such resistivity switching effects are often weak, and cannot be modulated by an external gate voltage - limiting their widespread usage. Using a back-gated 1T-TaS2/2H-MoS2 heterojunction, here we show that the usual resistivity switching in TaS2 due to different phase transitions is accompanied with a surprisingly strong modulation in the Schottky barrier height (SBH) at the TaS2/MoS2 interface - providing an additional knob to control the degree of the phase-transition-driven resistivity switching by an external gate voltage. In particular, the commensurate (C) to triclinic (T) phase transition results in an increase in the SBH owing to a collapse of the Mott gap in TaS2. The change in SBH allows us to estimate an electrical Mott gap opening of ~71 +/- 7 meV in the C phase of TaS2. On the other hand, the nearly-commensurate (NC) to incommensurate (IC) phase transition results in a suppression in the SBH, and the heterojunction shows a gate-controlled resistivity switching up to 17.3, which is ~14.5 times higher than that of standalone TaS2. The findings mark an important step forward showing a promising pathway to externally control as well as amplify the CDW induced resistivity switching. This will boost device applications that exploit these phase transitions, such as ultra-broadband photodetection, negative differential conductance, fast oscillator and threshold switching in neuromorphic circuits.Comment: Accepted for publication in Physical Review Applie

Strong Single- and Two-Photon Luminescence Enhancement by Nonradiative Energy Transfer across Layered Heterostructure

The strong light-matter interaction in monolayer transition metal dichalcogenides (TMDs) is promising for nanoscale optoelectronics with their direct band gap nature and the ultra-fast radiative decay of the strongly bound excitons these materials host. However, the impeded amount of light absorption imposed by the ultra-thin nature of the monolayers impairs their viability in photonic applications. Using a layered heterostructure of a monolayer TMD stacked on top of strongly absorbing, non-luminescent, multi-layer SnSe2, we show that both single-photon and two-photon luminescence from the TMD monolayer can be enhanced by a factor of 14 and 7.5, respectively. This is enabled through inter-layer dipole-dipole coupling induced non-radiative Forster resonance energy transfer (FRET) from SnSe2 underneath which acts as a scavenger of the light unabsorbed by the monolayer TMD. The design strategy exploits the near-resonance between the direct energy gap of SnSe2 and the excitonic gap of monolayer TMD, the smallest possible separation between donor and acceptor facilitated by van der Waals heterojunction, and the in-plane orientation of dipoles in these layered materials. The FRET driven uniform single- and twophoton luminescence enhancement over the entire junction area is advantageous over the local enhancement in quantum dot or plasmonic structure integrated 2D layers, and is promising for improving quantum efficiency in imaging, optoelectronic, and photonic applications

Psychiatric morbidities among patients with type-2 diabetes mellitus attending outpatient department in a rural area of North India

Background: Both diabetes mellitus and psychiatric morbidities are widely prevalent diseases which show a discerning upward trend globally. Coexistence of diabetes and psychiatric morbidities usually manifests as impaired quality of life and poor treatment adherence. Objectives: The study aimed to estimate the prevalence of psychiatric morbidities among rural diabetic patients and to determine their association with different variables. Methodology: The present cross-sectional study was conducted in CHC of Rural Health Block attached with PG Department of Community Medicine GMC (Government Medical College) Jammu. The eligible diabetic patients attending medical outpatient department services were enrolled using a consecutive sampling method. DAS scale was used to assess psychiatric morbidity among the study subjects. Results: The findings revealed that the prevalence of psychiatric morbidity in the study participants was 38.9%, 68.5% and 25.64% for depression, anxiety and stress, respectively. Psychiatric morbidities were slightly higher in female patients and were significantly associated with age, marital status, sedentary lifestyle, history of substance abuse, duration of diabetes, presence of complications and underlying morbidities (P < 0.05). Conclusions: The prevalence of anxiety and depression among rural diabetic patients was found to be quite high. Diabetic patients need thorough screening for psychiatric evaluation, and there is an urgent need for psychiatric counselling at regular intervals

Multimodality Management of Two Pairs of Pyopagus Twins

Background and Aim: Conjoined twins, due to their rarity and complex anatomy, pose not only a technical, but also a physiological challenge for their separation, with each case being uniquely distinct. The aim of the present article is to describe the surgical approach and management strategy for two cases of pyopagus conjoined twins operated at our center. Case Report: Case 1: Antenatally detected conjoined twin girls presented postnatally to our centre. They were found to have a common vestibule with single anal opening facing partially away from each other. On evaluation they were found to have a single sacrum and fused conus and filum terminale. They were taken up for separation at 2years of age & the 24hour long surgery, culminated in successful separation. The children had good post-operative outcome at 10months post separation. Case 2: Conjoined pyopagus twin girls presented postnatally, and were found to have fused cords, having a terminal syrinx and partially separate sacrum. They were separated at 2.5 years of age, with a multi-departmental effort and coordination. They are doing well 2 months post-operatively. Conclusion: A multidisciplinary team support with thorough preoperative planning significantly aids in improving the outcome of surgical separation. This has been possible by using modern technology. Each reported case contributes significantly to literature

QU-BraTS : MICCAI BraTS 2020 Challenge on QuantifyingUncertainty in Brain Tumor Segmentation - Analysis of Ranking Scores and Benchmarking Results

Deep learning (DL) models have provided the state-of-the-art performance in a wide variety of medical imaging benchmarking challenges, including the Brain Tumor Segmentation (BraTS) challenges. However, the task of focal pathology multi-compartment segmentation (e.g., tumor and lesion sub-regions) is particularly challenging, and potential errors hinder the translation of DL models into clinical workflows. Quantifying the reliability of DL model predictions in the form of uncertainties, could enable clinical review of the most uncertain regions, thereby building trust and paving the way towards clinical translation. Recently, a number of uncertainty estimation methods have been introduced for DL medical image segmentation tasks. Developing scores to evaluate and compare the performance of uncertainty measures will assist the end-user in making more informed decisions. In this study, we explore and evaluate a score developed during the BraTS 2019-2020 task on uncertainty quantification (QU-BraTS), and designed to assess and rank uncertainty estimates for brain tumor multi-compartment segmentation. This score (1) rewards uncertainty estimates that produce high confidence in correct assertions, and those that assign low confidence levels at incorrect assertions, and (2) penalizes uncertainty measures that lead to a higher percentages of under-confident correct assertions. We further benchmark the segmentation uncertainties generated by 14 independent participating teams of QU-BraTS 2020, all of which also participated in the main BraTS segmentation task. Overall, our findings confirm the importance and complementary value that uncertainty estimates provide to segmentation algorithms, and hence highlight the need for uncertainty quantification in medical image analyses. Our evaluation code is made publicly available at https://github.com/RagMeh11/QU-BraT