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