Auger-mediated processes and photoluminescence in group iv semiconductor nanostructures

Group IV semiconductors (Si, Ge) are inefficient light emitting materials due to their indirect bandgap structure. Nanostructures of Si, Ge, and SiGe however, have shown relatively high photoluminescence (PL) quantum efficiency (QE) at low carrier concentrations. At higher carrier concentrations, the PL QE of these nanostructures is drastically reduced due to the onset of a fast non-radiative process attributed to Auger recombination. Moreover, this onset occurs earlier in structures with reduced physical dimensions, than in bulk material. The study of Auger-mediated processes in group IV nanostructures is therefore critical to understanding the physics of carrier recombination and photonic device limitations. This work investigates recombination mechanisms in two such systems: the silicon/silicon germanium three-dimensional (3D) nanostructure system, and the silicon-on-insulator (SOI) system. Recombination mechanisms are studied by several experimental techniques. One approach explores the steady state PL spectroscopy and PL dynamics under pulsed excitations with varying concentrations of photo-generated charge carriers in the investigated systems. Another important technique uses selective, wavelength dependent photoexcitation to generate carriers up to varying depths in the nanostructures, enabling the understanding of local differences in PL properties through the thickness of structures. Several interesting observations are reported and underlying recombination mechanisms are discussed. For the Si/SiGe 3D nanostructure system, these include a reversible degradation of the PL after a few minutes of relative stability, an Auger Fountain mechanism that redistributes charge carriers within the nanostructure, and a severe reduction of the exciton diffusion length. For the SOI system, an apparently successful competition of the radiative recombination of carriers in a condensed excitonic phase with Auger processes is observed. The influence of the Si/SiO2 interface on the recombination mechanism in this system is emphasized. Results of the experiments show that the coexistence of a type II energy band alignment at Si/SiGe interfaces, the electron-hole-droplets in Si, and Auger-mediated processes results in several unusual photoluminescence properties in SiGe and Si nanostructures

Retrospective real-life efficacy assessment of teneligliptin in Indian T2DM patients

Background: Teneligliptin is been introduced recently in Indian market and data available are limited on Indian patients. Hence, the hospital based real life retrospective evaluation was planned out to evaluate, the efficacy of teneligliptin in type 2 diabetes mellitus in Indian population. Hence study was designed, a retrospective evaluation, of efficacy of teneligliptin in type 2 diabetes mellitus in Indian population.Methods: Data of 775 patients, who were prescribed teneligliptin was collected from hospital records. Teneligliptin 20mg was prescribed to all patients who were uncontrolled on other OHAs and for a mean duration of 8 weeks. Parameter evaluated in this study were change in FBG, PPBG and HbA1c from the baseline at 8week. With profile of outcome i.e. response and failure rates were also assessed with respect to age, gender, BMI and duration of diabetes.Results: Of 775 patients were enrolled, 427 were males and 348 females. The average age was 53.04 years among the study population. The mean duration of diabetes was 23 months. There was significant change in HbA1c, fasting and postprandial blood glucose levels at 8 week of teneligliptin therapy. Changes in HbA1c, FPG and PPG from baseline to end of study were-1.22±1.12% (p=0.001), -35.8±25.5mg/dl (p=0.001) and -60.7±28.6mg/dl (p=0.001) respectively. Out of 775 patients, 106 (13,7%) were non-responders where it was further sub analysed with different parameter such as age, gender, BMI and duration of diabetes in order to observe response of teneligliptin in diabetic patients.Conclusions: This real life retrospective evaluation showed efficacy of teneligliptin in real world scenario. It can be an effective alternative to conventional gliptins available for prescription in India

Giant hepatic hydatid cyst with sub-fascial extension treated by open minimally invasive surgery: a case report

<p>Abstract</p> <p>Introduction</p> <p>Hepatic hydatid disease can be successfully treated by a variety of modalities.</p> <p>Case Presentation</p> <p>We report a case of a 60 year old male with giant hepatic hydatid disease who presented with a huge cystic mass in the upper abdomen. Diagnosis was confirmed by serology, ultrasonography and CT scan. The patient was treated successfully by open minimally invasive surgery with minimum breaching of the peritoneal cavity using a laparoscopic trocar to evacuate the cyst.</p> <p>Conclusion</p> <p>The use of a laparoscopic trocar through a small abdominal incision in selected patients with hepatic hydatid disease with subfascial extension can be a safe, minimally-invasive option of treatment</p

PD-1 blockade with cemiplimab in advanced cutaneous squamous-cell carcinoma

BACKGROUNDNo systemic therapies have been approved for the treatment of advanced cutaneous squamous-cell carcinoma. This cancer may be responsive to immune therapy, because the mutation burden of the tumor is high and the disease risk is strongly associated with immunosuppression. In the dose-escalation portion of the phase 1 study of cemiplimab, a deep and durable response was observed in a patient with metastatic cutaneous squamous-cell carcinoma.METHODSWe report the results of the phase 1 study of cemiplimab for expansion cohorts of patients with locally advanced or metastatic cutaneous squamous-cell carcinoma, as well as the results of the pivotal phase 2 study for a cohort of patients with metastatic disease (metastatic-disease cohort). In both studies, the patients received an intravenous dose of cemiplimab (3 mg per kilogram of body weight) every 2 weeks and were assessed for a response every 8 weeks. In the phase 2 study, the primary end point was the response rate, as assessed by independent central review.RESULTSIn the expansion cohorts of the phase 1 study, a response to cemiplimab was observed in 13 of 26 patients (50%; 95% confidence interval [CI], 30 to 70). In the metastatic-disease cohort of the phase 2 study, a response was observed in 28 of 59 patients (47%; 95% CI, 34 to 61). The median follow-up was 7.9 months in the metastatic-disease cohort of the phase 2 study. Among the 28 patients who had a response, the duration of response exceeded 6 months in 57%, and 82% continued to have a response and to receive cemiplimab at the time of data cutoff. Adverse events that occurred in at least 15% of the patients in the metastatic-disease cohort of the phase 2 study were diarrhea, fatigue, nausea, constipation, and rash; 7% of the patients discontinued treatment because of an adverse event.CONCLUSIONSAmong patients with advanced cutaneous squamous-cell carcinoma, cemiplimab induced a response in approximately half the patients and was associated with adverse events that usually occur with immune checkpoint inhibitors

Fast luminescence in silicon-germanium nanostructures

Epitaxially-grown three-dimensional Si/SiGe nanostructures produce photoluminescence and electroluminescence in the desired spectral range of 1.3-1.6 \u3bcm. We show that by controlling and modifying such Ge-rich SiGe nanoclusters during growth it is possible to fabricate very fast and hence more efficient SiGe light-emitting devices. The physics of carrier recombination in these Si/SiGe nanostructures is discussed. The present results provide another possible route toward CMOS compatible light emitters.Peer reviewed: YesNRC publication: Ye

The analgesic efficacy of peritubal infiltration of 0.25% bupivacaine in percutaneous nephrolithotomy — A prospective randomized study

Background : Percutaneous nephrolithotomy is a routine endourologic procedure in patients with renal stones. Although it is less painful than open surgery, good postoperative analgesia is required to alleviate pain around nephrostomy tube. Materials and Methods : Sixty ASA grade I patients, 18 to 60 years of age, of either sex were randomized to receive 20 ml of 0.25% bupivacaine (group S) or 20 ml of normal saline (group C) through 23-gauge spinal needle along the nephrostomy tube under fluroscopic guidance at the end of the surgery. Postoperative pain score was assessed by visual and dynamic visual analog scores. When the scores were ≥4, rescue analgesia was given in the form of tramadol 1 mg/kg i.v. upto maximum 400 mg in 24 hours. Time to first demand analgesia and total dose of tramadol in first 24 hours was noted. Results : Pain scores at rest and during coughing as well as rescue analgesic requirements for first 24 hours were significantly less in the bupivacaine group than those of the control group (P < 0.05). The first request for demand analgesia was around 9 hours in group S, while in group C it was around 2.6 hours (P < 0.05). Total requirement of tramadol in group S was 119.3 mg and in C group it was 276.8 mg (P < 0.05). Conclusion : Peritubal infiltration of 0.25% bupivacaine is efficient in alleviating postoperative pain after PCNL

Strain engineering and luminescence in Si/SiGe three dimensional nanostructures

Strain engineering in composition-controlled Si-Si/Ge nanocluster multilayers with high germanium content (\ue2\u2c6\ubc 50%) is achieved by varying thicknesses of Si/SiGe layers and studied by low temperature photoluminescence (PL) measurements. The PL spectra show reduction in strained silicon energy bandgap and a splitting presumably associated with partial removal of heavy hole-light hole degeneracy in SiGe valence band. Time-resolved PL measurements performed under different excitation wavelengths show dramatically different PL lifetimes, ranging from \ue2\u2c6\ubc 2 \uce\ubcs to 10 ns and an unusually high PL quantum efficiency. The results are explained by using the Si/SiGe interface recombination model, which is supported by ultra-high resolution transmission and analytical electron microscopy measurements. \uc2\ua9 2011 Materials Research Society.Peer reviewed: YesNRC publication: Ye

Reversible degradation of photoluminescence in Si/SiGe three dimensional nanostructures

We report the degradation of low temperature photoluminescence (PL) from Si/SiGe three-dimensional cluster morphology nanostructures under continuous photoexcitation. The PL intensity initially decreases slowly for about 15 minutes, and then decreases rapidly, until only \ue2\u2c6\ubc 10% of the original PL intensity remains. A complete recovery of the PL requires restoring the sample temperature to - 300K. We propose that a slow accumulation of charge in SiGe clusters enhances the rate of Auger recombination and results in the observed PL degradation. \uc2\ua9 2012 Materials Research Society.Peer reviewed: YesNRC publication: Ye

Cardiovascular complications in kidney transplant recipients with COVID-19: A case series

Kidney transplant recipients (KTRs) are at a higher risk for developing severe COVID-19 which can be associated with cardiovascular complications. We studied five KTRs recipients infected with COVID-19 who developed severe cardiovascular complications. Two patients presented with ST segment myocardial infarction and two with clinically suspected myocarditis. One patient presented with atrial fibrillation. Two of these patients developed cardiogenic shock. Inflammatory markers were at peak during the event in four of these who had presented with severe COVID-19. Coronary angiography done in two patients with STEMI did not reveal any evidence of atherosclerotic coronary artery disease. Also, based on the cardiovascular (CV) risk estimation by Framingham score, four patients had low CV risk and one patient had intermediate CV risk. All five patients survived. Even with low CV risk, KTRs can develop myocardial injury and arrhythmias solely because of severe COVID-19

Mixed methods study on latent tuberculosis among agate stone workers and advocacy for testing silica dust exposed individuals in India

Abstract The 2021 tuberculosis (TB) preventive treatment guidelines in India included silicosis as a screening group, yet latent TB infection (LTBI) testing for silica-dust-exposed individuals is underemphasized. Focusing on an estimated 52 million silica-dust-exposed workers, particularly agate-stone workers in Khambhat, Gujarat, our study aims to estimate LTBI prevalence, identify predictors, and gather insights from TB and silicosis experts. Employing a sequential explanatory mixed-methods approach, a cross-sectional study involved 463 agate-stone workers aged ≥ 20 years in Khambhat, using IGRA kits for LTBI testing. In-depth interviews with experts complemented quantitative findings. Among agate-stone workers, 58% tested positive for LTBI, with predictors including longer exposure, type of work, and BCG vaccination. Our findings reveal a nearly double burden of LTBI compared to the general population, particularly in occupations with higher silica dust exposure. Experts advocate for including silica-dust-exposed individuals in high-risk groups for LTBI testing, exploring cost-effective alternatives like improved skin sensitivity tests, and shorter TB preventive treatment regimens to enhance compliance. Future research should explore upfront TB preventive treatment for silica-dust-exposed individuals with high LTBI prevalence and optimal exposure duration. This study underscores the urgent need for policy changes and innovative approaches to TB prevention among silica-dust-exposed populations, impacting global occupational health strategies