Revealing large-scale homogeneity and trace impurity sensitivity of GaAs nanoscale membranes

III-V nanostructures have the potential to revolutionize optoelectronics and energy harvesting. For this to become a reality, critical issues such as reproducibility and sensitivity to defects should be resolved. By discussing the optical properties of MBE grown GaAs nanomembranes we highlight several features that bring them closer to large scale applications. Uncapped membranes exhibit a very high optical quality, expressed by extremely narrow neutral exciton emission, allowing the resolution of the more complex excitonic structure for the first time. Capping of the membranes with an AlGaAs shell results in a strong increase of emission intensity but also to a shift and broadening of the exciton peak. This is attributed to the existence of impurities in the shell, beyond MBE-grade quality, showing the high sensitivity of these structures to the presence of impurities. Finally, emission properties are identical at the sub-micron and sub-millimeter scale, demonstrating the potential of these structures for large scale applications.Comment: just accepted in Nano Letters, http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.7b0025

Tuning growth direction of catalyst-free InAs(Sb) nanowires with indium droplets

The need for indium droplets to initiate self-catalyzed growth of InAs nanowires has been highly debated in the last few years. Here, we report on the use of indium droplets to tune the growth direction of self-catalyzed InAs nanowires. The indium droplets are formed in situ on InAs(Sb) stems. Their position is modified to promote growth in the or equivalent directions. We also show that indium droplets can be used for the fabrication of InSb insertions in InAsSb nanowires. Our results demonstrate that indium droplets can initiate growth of InAs nanostructures as well as provide added flexibility to nanowire growth, enabling the formation of kinks and heterostructures, and offer a new approach in the growth of defect-free crystals

Prevalence and correlates of inadequate glycaemic control: results from a nationwide survey in 6,671 adults with diabetes in Brazil

Diabetes is a significant public health burden on the basis of its increased incidence, morbidity, and mortality. This study aimed to estimate the prevalence of inadequate glycaemic control and its correlates in a large multicentre survey of Brazilian patients with diabetes. A cross-sectional study was conducted in a consecutive sample of patients aged 18 years or older with either type 1 or type 2 diabetes, attending health centres located in ten large cities in Brazil (response rate = 84%). Information about diabetes, current medications, complications, diet, and satisfaction with treatment were obtained by trained interviewers, using a standardized questionnaire. Glycated haemoglobin (HbA1c) was measured by high-performance liquid chromatography in a central laboratory. Patients with HbA1c ≥ 7 were considered to have inadequate glycaemic control. Overall 6,701 patients were surveyed, 979 (15%) with type 1 and 5,692 (85%) with type 2 diabetes. The prevalence of inadequate glycaemic control was 76%. Poor glycaemic control was more common in patients with type 1 diabetes (90%) than in those with type 2 (73%), P < 0.001. Characteristics significantly associated with improved glycaemic control included: fewer years of diabetes duration, multi professional care, participation in a diabetes health education program, and satisfaction with current diabetes treatment. Despite increased awareness of the benefits of tight glycaemic control, we found that few diabetic patients in Brazil met recommended glycaemic control targets. This may contribute to increased rates of diabetic complications, which may impact health care costs. Our data support the public health message of implementation of early, aggressive management of diabetes

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

Effects of telmisartan and valsartan on insulin resistance, visfatin and adiponectin levels in hypertensive patients with metabolic syndrome

WOS: 000254637500003Objective. The aims of this study were to compare the effect of telmisartan and valsartan on the blood and insulin sensitivity and adiponectin levels in hypertensive patients with metabolic syndrome. Patients and Methods. One hundred twenty male patients who met the criteria for metabolic syndrome defined as in ATP III enrolled in the sudy. All patients were randomized to receive treatment with telmisartan 80 mg (n=70) or valsartan 160 mg (n=50) once daily for 6 months. Serum insulin concentration was measured by chemiluminescence, plasma levels of adiponectin and visfatin by Enzyme linked immunosorbent assay kit (ELISA). Insulin resistance (IR) was estimated using the homeostasis model assessment (HOMA). Results: Mean HOMA-IR and adiponectin and visfatin levels were measured 3.00 +/- 0.9 and 5.93 +/- 0.3 mgr/ml and 23.45 +/- 6.1 mgr/ml in patients before starting treatment of telmisartan, respectively. They were changed to 2.4 +/- 0.5 and 6.71 +/- 0.5 mg/ml and 21.40 +/- 5.0 mg/ml at a 6 months period. In valsartan group, mean HOMA-IR and adiponectin and visfatin levels were measured 2.9 +/- 0.5 and 5.50 +/- 0.9 mg/ml 19.05 +/- 3.9 mg/ml before treatment, respectively. After a 6 months period, mean HOMA-IR and adiponectin and visfatin levels were found 3.00 +/- 0.9 and 6.24 +/- 0.7 mg/ml and 20.76 +/- 4.5 mg/ml, respectively. Conclusion: Telmisartan produced significant reductions from baseline in HOMA-IR and insulin levels, whereas valsartan did not. Both telmisartan and valsartan did no changed serum visfatin levels but they increased serum adiponectin concentrations by RAS blockade

Glucose tolerance tests in the singleton and twin pregnancy

Objective. Gestational diabetes mellitus (GDM) is defined as glucose intolerance that is detected for the first time during pregnancy. Normal pregnancy induces insulin resistance through the diabetogenic effects of placental hormones. Glucose tolerance test results in twin and singleton pregnancies were compared in this study. Subjects and Methods. A total of 360 pregnant women were studied. 200 women (mean age 31.60±2.10 yr) had singleton pregnancies (Group I) and 160 women (mean age 28.20±2.70 yr) had twin pregnancies (Group II). 50- g, 1- hour glucose tolerance test was conducted on the first prenatal visit. An abnormal glucose screen defined as glucose &gt; 140 mg/dL was followed by a 100g, 3-hour glucose tolerance test. Gestational diabetes was defined as the presence of two or more abnormal values during the 3-hour test. Results. Gestational diabetes was found in 4 of the 200 (2%) singleton pregnant women and 8 of the 160 (5%) twin pregnant women. Group I (Singleton) was further divided into two subgroups according to whether the 1-hr plasma glucose level was &lt; 140 mg/dl (Group Ia) or &gt;140 mg/dL (Group Ib). Likewise, Group II pregnancies was also divided into two subgoups on the same basis. Mean screening test glucose levels were found to be 127.8±14.94 mg/dL in Group Ia and 150.8 ± 18.1 mg/dL in Group Ib women. Mean screening test glucose levels of Group IIa subjects was 92.80 ± 18.30 mg/dL while that of Group IIb subjects was 154.8 ± 27.0 mg/dL. Mean 1st h glucose levels of 100-g glucose tolerance test was found to be 131.4 ± 32.58 mg/dL in Group I, and 112.5 ± 39.6 mg/dL in Group II. Mean 2nd h glucose tolerance test values were 133.2 ± 28.8 mg/dL in Group I and 100.6±28.8 mg/dL in Group II. Mean 3rd h glucose tolerance test values were 107.6 ± 23.58 mg/dl in Group I and 72±16.9 mg/dL in Group II. Conclusion: Glucose screening results and 100-g, 3- hour glucose tolerance test values have been found to be lower in twin pregnancies than in singleton pregnancies. Therefore, we suggest that these findings be taken into account in developing diagnostic criteria for gestational diabetes in twin or more pregnancies

Minimally invasive focused parathyroidectomy without using intraoperative parathyroid hormone monitoring or gamma probe

Background : Minimally invasive parathyroidectomy (MIP) is widely used worldwide for the treatment of primary hyperparathyroidism (pHPT). It is usually combined with a perioperative adjunct for high success rate. Aim : To demonstrate that MIP can be successfully performed in a selected group of patients with presumabally solitary adenoma as the cause of pHPT without using any perioperative adjuncts. Settings and Design : A prospective data analysis of two surgeons′ series from a teaching hospital in Turkey. Materials and Methods : Of the 47 patients referred with a diagnosis of pHPT during January 2004-May 2008, 30(63%) patients with sporadic pHPT with presumed solitary adenoma were included for analysis. These patients underwent MIP via focused lateral ( n=24) or anterior ( n=6) approach. Preoperative localization was done using 99 mTc-labelled sestamibi scan and ultrasonography. Only patients with concordant tests for single adenoma were selected for MIP. Serum parathyroid hormone and calcium levels were measured postoperatively and at follow-up visits. Statistical Analysis : Parametric data presented were analyzed with Excel XP (Microsoft, Redmond, WA, USA). Results : Barring one patient, all other patients were initially biochemically cured by MIP. One patient remained hypercalcemic, who was found to have a second adenoma at the second operation. During a mean follow-up of 16 (3-55) months, all patients were normocalcemic with a mean serum calcium level of 9.4 (8.9-10.2) mg/dl. Parathormone levels were persistantly elevated only in one patient (3.4%). No postoperative permanent complication was encountered. Conclusion : The results of MIP achieved in high-volume endocrine surgery centers can be replicated in low-volume center without any intraoperative adjuncts, in patients with overt clinical pHPT and concordant results of sestamibi and ultrasound

Quantitative microfluidic fluorescence microscopy to study vaso-occlusion in sickle cell disease

Photograph of a scene at Turner Falls