The Phototroph

Le silicium (100), nettoyé dans une enceinte ultravide, est caractérisé par spectroscopie Auger et diffraction d'électrons de très faible énergie. A partir d'un échantillon propre (diagramme de diffraction Si(100) 2 x 1, spectre Auger ne contenant que les transitions relatives au silicium en liaison 4-Si), l'oxydation est conduite in situ sous basse pression d'oxygène. L'examen des spectres Auger renseigne sur la nature et sur l'épaisseur des couches d'oxyde, dans la gamme de quelques Å à 30 Å. Une évaporation métallique permet de réaliser des structures MOS sans remise à l'air de l'échantillon. Le carbone, qui apparaît fréquemment comme principal contaminant de surface, n'est pas introduit par contamination à partir de l'atmosphère résiduelle lors de l'oxydation thermique. Sa localisation se situe au voisinage de l'interface Si-SiO2

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

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

Factors associated with persistent hypertension after puerperium among women with pre-eclampsia/eclampsia in Mulago hospital, Uganda

<p>Abstract</p> <p>Background</p> <p>Women with severe pre-eclampsia/eclampsia are at risk of developing chronic hypertension in future. Chronic hypertension may manifest initially as persistent hypertension at the end of the puerperium. The objective was to determine the incidence and maternal biochemical, hematological and socio-demographic risk factors for persistent hypertension in patients with pre-eclampsia/eclampsia.</p> <p>Methods</p> <p>This was a prospective cohort study conducted from November 2008 to May 2009 at Mulago hospital labor ward and postnatal clinic. Participants were 200 women managed for pre-eclampsia/eclampsia and followed up to the end of the puerperium. Data was collected through using pre-coded interviewer-administered questionnaires, checking medical records and laboratory investigations. STATA (release 9) software was used for data analysis. At bivariate analysis, the relative risk of persistent hypertension was estimated at the 95% confidence level. Using multivariate logistic regression analysis, factors that were independently associated with persistent hypertension were evaluated.</p> <p>Results</p> <p>Fifty four (27.7%) out of the total 195 women had persistent hypertension after puerperium. Serum creatinine and the age of the patient were the only factors associated with persistence of hypertension after puerperium.</p> <p>Conclusion</p> <p>Nearly every one in four mothers with pre-eclampsia/eclampsia are at risk of persistent hypertension after the puerperium. Serum creatinine, serum uric acid and participants' age were the only factors independently associated with persistence of hypertension after the puerperium.</p

Pre-pregnancy predictors of hypertension in pregnancy among Aboriginal and Torres Strait Islander women in north Queensland, Australia; a prospective cohort study

BACKGROUND Compared to other Australian women, Indigenous women are frequently at greater risk for hypertensive disorders of pregnancy. We examined pre-pregnancy factors that may predict hypertension in pregnancy in a cohort of Aboriginal and Torres Strait Islander women in north Queensland. METHODS Data on a cohort of 1009 Indigenous women of childbearing age (15–44 years) who participated in a 1998–2000 health screening program in north Queensland were combined with 1998–2008 Queensland hospitalisations data using probabilistic data linkage. Data on the women in the cohort who were hospitalised for birth (n = 220) were further combined with Queensland perinatal data which identified those diagnosed with hypertension in pregnancy. RESULTS Of 220 women who gave birth, 22 had hypertension in the pregnancy after their health check. The mean age of women with and without hypertension was similar (23.7 years and 23.9 years respectively) however Aboriginal women were more affected compared to Torres Strait Islanders. Pre-pregnancy adiposity and elevated blood pressure at the health screening program were predictors of a pregnancy affected by hypertension. After adjusting for age and ethnicity, each 1 cm increase in waist circumference showed a 4% increased risk for hypertension in pregnancy (PR 1.04; 95% CI; 1.02-1.06); each 1 point increase in BMI showed a 9% adjusted increase in risk (1.09; 1.04-1.14). For each 1 mmHg increase in baseline systolic blood pressure there was an age and ethnicity adjusted 6% increase in risk and each 1 mmHg increase in diastolic blood pressure showed a 7% increase in risk (1.06; 1.03-1.09 and 1.07; 1.03-1.11 respectively). Among those free of diabetes at baseline, the presence of the metabolic syndrome (International Diabetes Federation criteria) predicted over a three-fold increase in age-ethnicity-adjusted risk (3.5; 1.50-8.17). CONCLUSIONS Pre-pregnancy adiposity and features of the metabolic syndrome among these young Aboriginal and Torres Strait Islander women track strongly to increased risk of hypertension in pregnancy with associated risks to the health of babies.Sandra K Campbell, John Lynch, Adrian Esterman and Robyn McDermot

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

Second trimester inflammatory and metabolic markers in women delivering preterm with and without preeclampsia.

ObjectiveInflammatory and metabolic pathways are implicated in preterm birth and preeclampsia. However, studies rarely compare second trimester inflammatory and metabolic markers between women who deliver preterm with and without preeclampsia.Study designA sample of 129 women (43 with preeclampsia) with preterm delivery was obtained from an existing population-based birth cohort. Banked second trimester serum samples were assayed for 267 inflammatory and metabolic markers. Backwards-stepwise logistic regression models were used to calculate odds ratios.ResultsHigher 5-α-pregnan-3β,20α-diol disulfate, and lower 1-linoleoylglycerophosphoethanolamine and octadecanedioate, predicted increased odds of preeclampsia.ConclusionsAmong women with preterm births, those who developed preeclampsia differed with respect metabolic markers. These findings point to potential etiologic underpinnings for preeclampsia as a precursor to preterm birth

Inflammatory Aetiology of Human Myometrial Activation Tested Using Directed Graphs

There are three main hypotheses for the activation of the human uterus at labour: functional progesterone withdrawal, inflammatory stimulation, and oxytocin receptor activation. To test these alternatives we have taken information and data from the literature to develop causal pathway models for the activation of human myometrium. The data provided quantitative RT-PCR results on key genes from samples taken before and during labour. Principal component analysis showed that pre-labour samples form a homogenous group compared to those during labour. We therefore modelled the alternative causal pathways in non-labouring samples using directed graphs and statistically compared the likelihood of the different models using structural equations and D-separation approaches. Using the computer program LISREL, inflammatory activation as a primary event was highly consistent with the data (p = 0.925), progesterone withdrawal, as a primary event, is plausible (p = 0.499), yet comparatively unlikely, oxytocin receptor mediated initiation is less compatible with the data (p = 0.091). DGraph, a software program that creates directed graphs, produced similar results (p = 0.684, p = 0.280, and p = 0.04, respectively). This outcome supports an inflammatory aetiology for human labour. Our results demonstrate the value of directed graphs in determining the likelihood of causal relationships in biology in situations where experiments are not possible

Preeclampsia and Blood Pressure Trajectory during Pregnancy in Relation to Vitamin D Status

Every tenth pregnancy is affected by hypertension, one of the most common complications and leading causes of maternal death worldwide. Hypertensive disorders in pregnancy include pregnancy-induced hypertension and preeclampsia. The pathophysiology of the development of hypertension in pregnancy is unknown, but studies suggest an association with vitamin D status, measured as 25-hydroxyvitamin D (25(OH)D). The aim of this study was to investigate the association between gestational 25(OH)D concentration and preeclampsia, pregnancy-induced hypertension and blood pressure trajectory. This cohort study included 2000 women. Blood was collected at the first (T1) and third (T3) trimester (mean gestational weeks 10.8 and 33.4). Blood pressure at gestational weeks 10, 25, 32 and 37 as well as symptoms of preeclampsia and pregnancy-induced hypertension were retrieved from medical records. Serum 25(OH)D concentrations (LC-MS/MS) in T1 was not significantly associated with preeclampsia. However, both 25(OH)D in T3 and change in 25(OH)D from T1 to T3 were significantly and negatively associated with preeclampsia. Women with a change in 25(OH)D concentration of ≥30 nmol/L had an odds ratio of 0.22 (p = 0.002) for preeclampsia. T1 25(OH)D was positively related to T1 systolic (β = 0.03, p = 0.022) and T1 diastolic blood pressure (β = 0.02, p = 0.016), and to systolic (β = 0.02, p = 0.02) blood pressure trajectory during pregnancy, in adjusted analyses. There was no association between 25(OH)D and pregnancy-induced hypertension in adjusted analysis. In conclusion, an increase in 25(OH)D concentration during pregnancy of at least 30 nmol/L, regardless of vitamin D status in T1, was associated with a lower odds ratio for preeclampsia. Vitamin D status was significantly and positively associated with T1 blood pressure and gestational systolic blood pressure trajectory but not with pregnancy-induced hypertension