Effect of total pressure on the formation and size evolution of silicon quantum dots in silicon nitride films

The size of silicon quantum dots (Si QDs) embedded in silicon nitride (SiN(x)) has been controlled by varying the total pressure in the plasma-enhanced chemical vapor deposition (PECVD) reactor. This is evidenced by transmission electron microscopy and results in a shift in the light emission peak of the quantum dots. We show that the luminescence in our structures is attributed to the quantum confinement effect. These findings give a strong indication that the quality (density and size distribution) of Si QDs can be improved by optimizing the deposition parameters which opens a route to the fabrication of an all-Si tandem solar cell

Comparison of Sexually Transmitted Infections and Adverse Perinatal Outcomes in Underserved Pregnant Patients Before vs During the COVID-19 Pandemic in Texas

This cohort study assesses the rates of sexually transmitted infections (STI) and associated adverse perinatal outcomes among underserved pregnant patients during the COVID-19 pandemic in a public health system in Southeastern Texas

Charge photo-carrier transport from silicon nanocrystals embedded in SiO_2-based multilayer structures

© 2012 American Institute of Physics This work was supported by the French National Agency for Research (ANR) through the DUOSIL project. Financial support has also been partly funded by the RhôneAlpes region in the frame of the PHOSIL project.Experimental investigation of photoconductivity in Si-rich silicon oxide (SRSO)/SiO_2 multilayer (ML) structures prepared by magnetron reactive sputtering is reported. Photocurrent (PC) measurements show that the PC threshold increases with decreasing the thickness of SRSO layer. Photo-conduction processes in our samples are shown to be dominated by carrier transport through quantum-confined silicon nanocrystals embedded in the SiO_2 host. In addition, the observed bias-dependence of photocurrent intensity is consistent with a model in which carrier transport occurs by both tunneling and hopping through defect states in the silicon oxide matrix. A photocurrent density J_(ph) of 1-2mA cm^(-2) is extracted from our results. Although this photocurrent density along the ML absorber film is relatively low, the results presented in this work are believed to be a valuable contribution toward the implementation of all-Si tandem solar cells.French National Agency for Research (ANR)Rhône-AlpesDepto. de Física de MaterialesFac. de Ciencias FísicasTRUEpu

The regulation of RhoA at focal adhesions by StarD13 is important for astrocytoma cell motility

Malignant astrocytomas are highly invasive into adjacent and distant regions of the normal brain. Rho GTPases are small monomeric G proteins that play important roles in cytoskeleton rearrangement, cell motility and tumor invasion. In the present study, we show that the knock down of StarD13, a GTPase activating protein (GAP) for RhoA and Cdc42, inhibits astrocytoma cell migration through modulating focal adhesion dynamics and cell adhesion. This effect is mediated by the resulting constitutive activation of RhoA and the subsequent indirect inhibition of Rac. Using Total Internal Reflection Fluorescence (TIRF)-based Forster Resonance Energy Transfer (FRET), we show that RhoA activity localizes with focal adhesions at the basal surface of astrocytoma cells. Moreover, the knock down of StarD13 inhibits the cycling of RhoA activation at the rear edge of cells, which makes them defective in retracting their tail. This study highlights the importance of the regulation of RhoA activity in focal adhesions of astrocytoma cells and establishes StarD13 as a GAP playing a major role in this process. (C) 2013 Elsevier Inc All rights reserved

Antenatal corticosteroids impact the inflammatory rather than the antiangiogenic profile of women with preeclampsia

Circulating antiangiogenic factors and proinflammatory cytokines are implicated in the pathogenesis of preeclampsia. This study was performed to test the hypothesis that steroids modify the balance of inflammatory and proangiogenic and antiangiogenic factors that potentially contribute to the patient's evolving clinical state. Seventy singleton women, admitted for antenatal corticosteroid treatment, were enrolled prospectively. The study group consisted of 45 hypertensive women: chronic hypertension (n=6), severe preeclampsia (n=32), and superimposed preeclampsia (n=7). Normotensive women with shortened cervix (<2.5 cm) served as controls (n=25). Maternal blood samples of preeclampsia cases were obtained before steroids and then serially up until delivery. A clinical severity score was designed to clinically monitor disease progression. Serum levels of angiogenic factors (soluble fms-like tyrosine kinase-1 [sFlt-1], placental growth factor [PlGF], soluble endoglin [sEng]), endothelin-1 (ET-1), and proinflammatory markers (IL-6, C-reactive protein [CRP]) were assessed before and after steroids. Soluble IL-2 receptor (sIL-2R) and total immunoglobulins (IgG) were measured as markers of T- and B-cell activation, respectively. Steroid treatment coincided with a transient improvement in clinical manifestations of preeclampsia. A significant decrease in IL-6 and CRP was observed although levels of sIL-2R and IgG remained unchanged. Antenatal corticosteroids did not influence the levels of angiogenic factors but ET-1 levels registered a short-lived increase poststeroids. Although a reduction in specific inflammatory mediators in response to antenatal steroids may account for the transient improvement in clinical signs of preeclampsia, inflammation is unlikely to be the major contributor to severe preeclampsia or useful for therapeutic targeting. © 2014 American Heart Association, Inc

WASP family members and formin proteins coordinate regulation of cell protrusions in carcinoma cells

We examined the role of the actin nucleation promoters neural Wiskott-Aldrich syndrome protein (N-WASP) and WAVE2 in cell protrusion in response to epidermal growth factor (EGF), a key regulator in carcinoma cell invasion. We found that WAVE2 knockdown (KD) suppresses lamellipod formation and increases filopod formation, whereas N-WASP KD has no effect. However, simultaneous KD of both proteins results in the formation of large jagged protrusions with lamellar properties and increased filopod formation. This suggests that another actin nucleation activity is at work in carcinoma cells in response to EGF. A mammalian Diaphanous–related formin, mDia1, localizes at the jagged protrusions in double KD cells. Constitutively active mDia1 recapitulated the phenotype, whereas inhibition of mDia1 blocked the formation of these protrusions. Increased RhoA activity, which stimulates mDia1 nucleation, was observed in the N-WASP/WAVE2 KD cells and was shown to be required for the N-WASP/WAVE2 KD phenotype. These data show that coordinate regulation between the WASP family and mDia proteins controls the balance between lamellar and lamellipodial protrusion activity

Kyphoplasty vs Vertebroplasty: A Systematic Review of Height Restoration in Osteoporotic Vertebral Compression Fractures

Background: Back pain is a leading cause of morbidity in older US adults, especially those with osteoporosis. Osteoporotic vertebral compression fractures (OVCF) commonly occur in people with osteoporosis. ~1/3 of OVCF are symptomatic with acute or chronic low back pain. Annual US cases of osteoporosis with OVCF are ~700,000/year. OVCF and osteoporosis cause high levels of morbidity, decreased functional independence, and chronic pain. Conservative treatment for OVCF is often insufficient for many patients. Insufficient vertebral height caused by OVCF can lead to spinal deformities, reduced pulmonary function, depression, reduced mobility, and lower quality of life. Surgical correction is a viable option for increasing vertebral height in patients with OVCF. Kyphoplasty and vertebroplasty are vertebral augmentation therapies that can restore bone height for the alleviation of OVCF. Both procedures involve injection of a polymer cement into sites of fracture. Only kyphoplasty involves using an inflatable balloon to first make space for polymer injection. These minimally invasive procedures are recommended for patients who have OVCF but are refractory to conventional therapies. Also, patients with benign bone tumors or traumatic acute vertebral compression fractures with a local kyphotic angle greater than 15 degrees can benefit from these procedures. The aim of our systematic review was to identify the overall effectiveness of kyphoplasty and vertebroplasty. Height restoration after treatment was used as the key indicator of therapeutic success. Restoration of function and pain relief were also assessed. Purpose: To critically investigate whether vertebral body height restoration correlates with pain relief after kyphoplasty and vertebroplasty. Primary Outcome: height restoration. Secondary Outcomes: pain relief, functionality, cement leakage, Cobb’s Angle, wedge angle restoration, kyphosis angle restoration, and Gardner’s angle. We assessed only randomized controlled trials (RCTs) to generate a more robust and clinically applicable. We also provide an update on the literature comparing kyphoplasty versus vertebroplasty for height restoration, pain relief, and function restoration. We searched 6 databases to ensure that the review was comprehensive. Methods: We performed a systematic review per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol. Level II randomized controlled trials assessing kyphoplasty and/or vertebroplasty were included. Study selection inclusion criteria: patients \u3e 18 years, in English, study of OVCF, active comparator vs placebo, outcome measure of height restoration, with pain relief and functionality as secondary outcomes. Of 4147 individual articles, 238 articles were screened, and 33 were analyzed. Of the 33 analyzed studies, 6 compared kyphoplasty to vertebroplasty. Results: Vertebral Height Restoration 7 studies of vertobroplasty 2 showed height loss 1 showed height restoration 2 showed absolute height gain 20 studies of kyphoplasty None showed height loss 8 showed height restoration 8 showed absolute height gain 6 head-to-head comparisons 3 showed correlation of cement injection volume with improved height 5 favored kyphoplasty for height restoration Alleviation of Pain: Assessed by visual analogue scale (VAS)score 6 of 6 vertebroplasty studies showed reduced postop pain 6 of 18 kyphoplasty studies showed sustained reduced pain at 12 months 6 studies compared kyphoplasty & vertebroplasty and none saw a difference between the 2 for reducing postop pain Restoration of Function Assessed by Oswestry disability index (ODI) 3 studies showed improved ODI after vertebroplasty at 18 to 36 months postop 4 studies showed improved ODI at 12 months after kyphoplasty 3 studies compared kyphoplasty & vertebroplasty and all showed lower postop ODI Conclusions: Both kyphoplasty and vertebroplasty are effective treatments for OVCF and are viable options for OVCF patients. Both treatments restored some vertebral body height, reduced kyphosis angle, improved Cobbs angle, and improved wedge angle. Both treatments showed similar benefits of pain reduction and improved functionality. It was unclear whether fracture type or age of fracture influence procedure outcomes. Kyphoplasty has the possibility of cement leakage, which can lead to negative outcomes. It was not possible to conclude whether one approach was superior.https://scholarlycommons.henryford.com/sarcd2021/1006/thumbnail.jp