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SrTiO3 (STO) is a well‐known perovskite oxide often used, among others, as a crystalline substrate for epitaxial deposition. However, its indirect bandgap of 3.25 eV is too high for solar applications. Tentative experiments to reduce its bandgap are very welcome. To this end, sulfurization of STO substrates using ion implantation is performed. The simulated profile is controlled by time‐of‐flight secondary‐ion mass spectrometry. S is at least partially inserted into the STO lattice, as evidenced by X‐ray diffraction and X‐ray photoelectron spectroscopy. UV–vis spectroscopy indicates a drastic reduction of the bandgap of S:STO from 3.25 eV (indirect) down to 2.14 eV for 10% S:STO, a trend also observed by spectroscopic ellipsometry. The results are confronted to ab initio calculations. Besides bandgap, the valence band level, that is the ionization energy, is determined by ambient‐pressure photoemission spectroscopy so that the complete energy diagrams could be plotted. This work paves the way for tuning the bandgap of perovskites in a highly controlled manner for solar energy applications. [ABSTRACT FROM AUTHOR]

Multivariate longitudinal data are used in a variety of research areas not only because they allow to analyze time trajectories of multiple indicators, but also to determine how these trajectories are influenced by other covariates. In this article, we propose a mixture of longitudinal factor analyzers. This model could be used to extract latent factors representing multiple longitudinal noisy indicators in heterogeneous longitudinal data and to study the impact of one or several covariates on these latent factors. One of the advantages of this model is that it allows for measurement non‐invariance, which arises in practice when the factor structure varies between groups of individuals due to cultural or physiological differences. This is achieved by estimating different factor models for different latent classes. The proposed model could also be used to extract latent classes with different latent factor trajectories over time. Other advantages of the model include its ability to take into account heteroscedasticity of errors in the factor analysis model by estimating different error variances for different latent classes. We first define the mixture of longitudinal factor analyzers and its parameters. Then, we propose an EM algorithm to estimate these parameters. We propose a Bayesian information criterion to identify both the number of components in the mixture and the number of latent factors. We then discuss the comparability of the latent factors obtained between subjects in different latent groups. Finally, we apply the model to simulated and real data of patients with chronic postoperative pain. [ABSTRACT FROM AUTHOR]

Introduction: Placenta accreta spectrum (PAS) is a serious condition with a mortality as high as 7%. However, the factors associated with this type of death have not been adequately described, with an almost complete lack of publications analyzing the determining factors of death in this disease. The aim of our work is to describe the causes of death related to PAS and to analyze the associated diagnosis and treatment problems. Material and methods: This is an inter‐continental, multicenter, descriptive, retrospective study in low‐ and middle‐income countries. Maternal deaths related to PAS between January 2015 and December 2020 were included. Crucial points in the management of PAS, including prenatal diagnosis and details of the surgical treatment and postoperative management, were evaluated. Results: Eighty‐two maternal deaths in 16 low‐ and middle‐income countries, on three continents, were included. Almost all maternal deaths (81 cases, 98.8%) were preventable, with inexperience among surgeons being identified as the most relevant problem in the process that led to death among 87% (67 women) of the cases who had contact with health services. The main cause of death associated with PAS was hemorrhage (69 cases, 84.1%), and failures in the process leading to the diagnosis were detected among 64.6% of cases. Although the majority of cases received medical attention and 50 (60.9%) were treated at referral centers for severe obstetric disease, problems were identified during treatment in all cases. Conclusions: Lack of experience and inadequate surgical technique are the most frequent problems associated with maternal deaths in PAS. Continuous training of interdisciplinary teams is critical to modify this tendency. [ABSTRACT FROM AUTHOR]

Molding of a dense film of spherical poly(acrylate/methyl methacrylate) (PAA‐PMMA) beads is used as unique templating agent to obtain TiO2 scaffold layers with controlled porosity. The porosity obtained is of hundreds of nanometers, much larger than the one typically reported for the porous layers of Grätzel‐ or perovskite‐ type cells. It is shown that the film thickness and roughness, and the pore size are strongly dependent on the roughness of the substrate for identical deposition conditions. In order enhance the conductivity of the TiO2 scaffold layer, a sol‐gel mixture of titanium and tin is also successfully tested. Such films are potentially interesting as electron transport layer in perovskite solar cells since they allow an enhanced specific surface and a better control of the interface with the infiltrated photoactive material which are essential for an efficient charge collection. [ABSTRACT FROM AUTHOR]

We report herein on the use of 13 ternary europium(III) complexes as downshifting (DS) material for copper indium gallium selenide (CIGS) solar cells. Their general formulae are [Eu(β -Dik)3(NL) x] and [Eu(L)3], in which β-Dik = 2-thenoyltrifluoroacetonate, 4,4,4-trifluoro-1-phenyl-1,3-butanedione and 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione and NL = diphenyl sulfoxide ( x = 2), triphenylphosphine oxide ( x = 2), bis[2-(diphenylphosphino)phenyl] ether ( x = 1), 5,6-epoxy-5,6-dihydro-1,10-phenanthroline ( x = 1) and 2-( N, N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine ( x = 1) and L = 4-(4′- tert-butylbiphenyl-4-yl)-2,2′-bipyridine-6-carboxylate. Tris(β-diketonate) ternary EuIII complexes are very good candidates for DS applications, and some of them have shown very promising results when embedded in a host organic polymer matrix typically used for solar cell encapsulations. Herein we report a new method for the direct deposition of luminescent nanolayer films on CIGS solar cells. Highly luminescent nano- and microlayer films with a thickness in the range of 150 nm to 10 µm have been obtained and characterized by optical microscopy, profilometry, spectrofluorimetry and external quantum efficiency (EQE) measurements. The efficient conversion of incident photons into red light was observed for films with a thickness of 400-600 nm, leading to a significant improvement in the EQE and short-circuit current density ( Jsc) in the UV region up to 0.81 mA/cm2. The absolute conversion efficiency increased by up to 0.8 %. The nanofilms, with the exception of those containing naphthyl derivatives, were found to be photostable and therefore represent a competitive alternative to doped polymer encapsulants. [ABSTRACT FROM AUTHOR]

CZTS thin films are deposited onto glass and Mo-coated glass substrates by ultrasonic spray technique, followed by a sulfurization under argon atmosphere at 500 °C during 1 h. We have investigated how the addition of the alkali can influence Cu2ZnSnS4 thin films properties. X-ray diffraction and Raman spectroscopy proved that CZTS has the kesterite structure with a preferential orientation along 112. The values of Cu/(Zn+Sn) and (Zn/Sn) ratios, determined by energy dispersive spectroscopy, for undoped CZTS and alkali-doped CZTS are observed to be affected by the alkali doping. The electrical resistivity, for CZTS films deposited on glass substrates, decreased after alkali doping from 9.2 10−1 Ω · cm for undoped CZTS to reach 1.8 10−1 and 4.2 10−1 Ω · cm for 15% content of Na and K, respectively. [ABSTRACT FROM AUTHOR]

In this work, we investigate the direct formation of crystalline silicon thin films using ECR-PECVD process on aluminum substrates for solar cells applications. The aluminum substrate offers the advantages of being flexible and highly reflective in addition to serve as the back contact for the cell device. The substrates were pure aluminum or silicon rich aluminum sheets. Monocrystalline silicon substrates were used as reference substrates. Silane and hydrogen were used as precursor gases. Silicon growth was done at different substrate temperatures. The grown silicon films were characterized by Raman spectroscopy, SIMS and XRD techniques. Silicon thicknesses between 230 and 1370 nm were obtained on different types of aluminum substrates. The analyses show that the grown silicon films formed at 480 °C under SiH4: 40 sccm and H2 = 10 sccm are amorphous silicon at the initial stage and become nanocrystalline (nc-Si:H) as the deposition proceeds. The crystalline fraction of those films extracted from Raman spectra is found around 40-60% and XRD analysis shows grain silicon size between 41 and 83 Å. Finally, SIMS analysis have revealed graded doping distribution profiles which is indicative of the formation of a nc-Si:H(i)/nc-Si:H (p+)/Al substrate, well suited for solar cell structures. [ABSTRACT FROM AUTHOR]

Zinc oxide thin films co-doped with rare earth (Nd and Tb) have been grown on heated glass substrates (350 °C) by chemical spray pyrolysis method. The effect of doping rate on structural, optical, and electrical properties is studied. X-ray diffraction confirmed that all the prepared films have the hexagonal wurtzite structure with a preferred orientation toward the c-axis. No peaks belonging to rare earth or their oxides are observed in the limit of XRD technique detection. UV-visible-NIR spectra show a significant optical transmission above 75%, which decrease with the increase of Tb concentration and an increase of the optical band gap with the insertion of the rare earth dopants. Photoluminescence spectra are dominated by an emission band attributed to the radiative recombination of excitons and a large band attributed to the various defects in ZnO matrix. In addition band emissions from Nd3+ ions are observed in the (Nd, Tb) co-doped films. Electrical resistivity of about 3.7 10-2 Ω · cm was achieved. [ABSTRACT FROM AUTHOR]

Silicon-rich silicon nitride films with different stoichiometry were grown on the silicon substrate using the plasma-enhanced chemical vapor deposition. The excess silicon content in the films was monitored via varying the NH3/SiH4 gas flow ratio from 0.45 up to 1.0. High-temperature annealing was employed to produce the silicon nanocrystals (NCs) in the films and to enhance the photoluminescence in the range of 1.6-2.9 eV. Optical parameters of films were estimated by means of spectroscopic ellipsometry. Photoluminescence (PL) and its temperature dependences were studied as well. PL spectra were found to be complex due to the contribution of several radiative channels in the emission process. It was determined that their competition leads to the non-monotonous variation of total PL peak position with the increase of Si excess content. The analysis of PL temperature dependencies has revealed that the 'blue-orange' emission is owing to the radiative host defects, whereas the 'red' PL band is caused by the exciton recombination in Si NCs. The way to control emission is discussed. [ABSTRACT FROM AUTHOR]

This work reports on the use of a ternary europium (III) complex as downshifting (DS) material for copper indium gallium selenide (CIGS) solar cells, [Eu(tta)3(tppo)2] ( tta = 2-thenoyltrifluoroacetonate and tppo = triphenylphosphine oxide). It is synthesized by one-pot reaction and embedded into poly(ethylene- co-vinyl acetate) (EVA), poly(methyl methacrylate) (PMMA), and poly(vinyl butyral- co-vinyl alcohol- co-vinyl acetate) (PVB) matrices. Their photophysical properties are investigated and compared with the complex alone. No significant variations in transmittance, emission, excitation spectra, and quantum yield are detected between [Eu(tta)3(tppo)2] alone and embedded into EVA, PMMA, and PVB. CIGS solar cells are encapsulated using these compounds, leading to an improvement of the external quantum efficiency (EQE) mostly in UV region. The EQE at 360 nm increases up to 56% compared to 14% without the encapsulant. The luminescent downshifting (LDS) material is responsible for an increase in the short-circuit current ( Jsc) calculated from the EQE in the 300-420 nm region, by 0.55 mA cm−2 compared to the value of 0.59 mA cm−2 obtained from theoretical prediction. In the best case, an increase of the CIGS solar cell conversion efficiency by 0.8% absolute is observed thanks to the LDS material. [ABSTRACT FROM AUTHOR]

Luminescent lanthanide-doped oxides, nanoparticles, nanocrystals, and coordination complexes are major tools in the fields of optical and laser materials, telecommunications, medical imaging, and fluoroimmunoassays. In particular, coordination complexes are efficient energy converters with high photostability, large ligand-induced Stokes shifts, and tunable excitation and emission spectra. However, their application as light downshifting materials for solar cells has not yet been widely explored. This third generation solar cell concept enables to increase the efficiency of standard solar cells-such as Si or copper indium gallium (di)selenide (CIGS)-that have low performance for ultraviolet photons. The incorporation of such a converter in solar module encapsulants can provide a cheap and effective way to integrate photon conversion. Here, encapsulants functionalised by photon downshifting coordination complexes have been spin-coated on silicon solar cells. For all the coordination complexes, an increase of the spectral response of the solar cells is observed in the ultraviolet region. In the best case, a relative increase of 8% of the conversion efficiency of the solar cell is observed. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we propose an automatic selection of the bandwidth of the recursive kernel estimators of a regression function defined by the stochastic approximation algorithm. We showed that, using the selected bandwidth and the stepsize which minimize the mean weighted integrated squared error, the recursive estimator will be better than the non-recursive one for small sample setting in terms of estimation error and computational costs. We corroborated these theoretical results through simulation study and a real dataset. [ABSTRACT FROM AUTHOR]

This paper addresses issues in the microwave phytosanitary treatment of frozen wood. Four eastern Canadian wood species are used: trembling aspen, yellow birch, white birch, and sugar maple. The nonlinear heat conduction problem involving phase changes such as wood freezing is solved by a volumetric specific enthalpy-based finite element method. Dielectric and thermophysical properties are functions of temperature and moisture content. As an application, we studied the dielectric heating of four wood species as a function of moisture content and microwave properties. [ABSTRACT FROM AUTHOR]

Aims Several reports have suggested a relationship between male sex and albuminuria in Type 2 diabetes, but impact on renal function decline has not been established. Our aim was to describe the influence of sex on renal function decline in Type 2 diabetes. Methods SURDIAGENE, an inception cohort, consisted in 1470 people with Type 2 diabetes. Patients without renal replacement therapy and with ≥ 3 serum creatinine determinations during follow-up prior to end-stage renal disease were included in the study. Estimated glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Primary outcome was steep estimated glomerular filtration rate ( eGFR) decline, defined as a yearly slope value lower than -3.5 ml min−1 1.73 m−2. Secondary outcomes were estimated glomerular filtration rate trajectories according to sex and occurrence of end-stage renal disease. Results A total of 22 914 serum creatinine determinations were considered in 1146 participants (60% men), aged 65 ± 11 years, with a median follow-up duration of 5.7 years (range 0.1-10.2). Median yearly estimated glomerular filtration rate slope was -1.31 ml min−1 1.73 m−2 in women and -1.77 ml min−1 1.73 m−2 in men ( P < 0.001). Men were more likely than women to develop end-stage renal disease (22 men vs. 7 women; Plog-rank = 0.03). Male sex was an independent risk factor of steep estimated glomerular filtration rate decline [adjusted odds ratio = 1.33 (1.02-1.76), P = 0.04] after adjustment for age, time from diagnosis of Type 2 diabetes, glycated haemoglobin, systolic blood pressure and urinary albumin:creatinine ratio. A multivariable linear mixed-effects model showed a significant difference of estimated glomerular filtration rate trajectories between men and women ( P < 0.001). Conclusion Male sex is an important independent factor associated with renal function decline in Type 2 diabetes. [ABSTRACT FROM AUTHOR]

The heating process of frozen wood exposed to plane microwaves is numerically investigated. The nonlinear heat conduction problem involving phase change such as wood freezing is solved by a specific 3D volumetric enthalpy-based finite element method. Dielectric and thermal properties are a function of temperature and moisture content. The numerical model is validated by experimental and analytical means. As an application, we studied the effect of moisture content and frequency on microwave heating of trembling aspen wood. [ABSTRACT FROM AUTHOR]

The aim of Solarforce is the achievement of high efficiency solar cells made out of ≤100 µm thick multicrystalline silicon wafers produced by the Ribbon on Sacrificial Template (RST) process. For a first evaluation of the RST material, solar cells were fabricated on p-type RST wafers with different processes. The first conclusion is that the density of silicon carbide inclusions has to be lowered to obtain better FF values, and in turn a better homogeneity in cell performances. Secondly, conversion efficiency is found to be limited around 14% by low bulk minority carrier lifetime values, limiting both Voc and Leff. ICP-MS analyses on RST material show that this lifetime may be improved with the possible achievement of low metallic impurity content in the wafers, under 1 ppb wt. Further enhancement is also shown to be possible with the n doping of RST material, a well controlled process in ribbon growth (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Silicon rich silicon oxynitride (SRSON) were deposited by ECR-PECVD to form silicon nanostructures. The effect of argon flow during the deposition was investigated. The silicon nanoparticles were fabricated by a classical thermal treatment of SRSON films. The structural properties of the SRSON films were investigated by RBS and FTIR measurements. We show that the silicon excess in the SiOxNy matrix changes slightly with Ar flow but it has a significant impact on the silicon nanoparticles morphology embedded in the silicon oxynitride layer. Different shapes for silicon nanostructures ranging from separated Si nanocrystals to Si nanocolumns were formed as studied by energy-filtred transmission electron microscopy analysis (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Objective Urgent evaluation and treatment of transient ischemic attack (TIA) patients in a dedicated TIA clinic may reduce the 90-day stroke risk by 80%. ABCD2 (Age, Blood pressure, Clinical features, Duration, Diabetes) score and magnetic resonance imaging abnormalities help to identify patients at high risk of stroke. Our aim was to determine whether the use of transcranial Doppler (TCD) examination on arrival at the TIA clinic yields additional information that facilitates the identification of patients at high risk of stroke recurrence. Methods Between January 2003 and December 2007, 1,881 patients were admitted to SOS-TIA clinic (a TIA clinic with around-the-clock access). Clinical and vascular assessment included TCD performed by a neurologist immediately after admission. Stroke prevention measures were initiated on arrival, in accordance with guidelines. All patients were followed for 1 year after presentation to the SOS-TIA clinic. Results A total of 1,823 TCD examinations were performed within 4 hours of admission. Intracranial narrowing or occlusion was found in 8.8% of patients, and was independently associated with age, hypertension, and diabetes. After 1-year follow-up on best preventive therapy, the incidence of recurrent vascular events (intracranial revascularization for TIA recurrence, stroke, myocardial infarction, and vascular death combined) was 7.0% in patients with intracranial narrowing or occlusion and 2.4% in those without (log-rank, p = 0.007). The hazard ratio of combined outcome for the presence of intracranial narrowing or occlusion was 2.29 (95% confidence interval [CI], 1.15-4.56; p = 0.02) in multivariate analysis including age, gender, hypertension, and diabetes, and was 2.50 (95%CI, 1.24-5.05; p = 0.01) in multivariate analysis including ABCD2 score ≥4. Interpretation Immediate TCD examination on arrival at the TIA clinic is feasible and could help to identify patients at high risk of vascular events recurrence. This study supports a systematic intracranial vascular examination in the initial management of TIA. ANN NEUROL 2010;68:9-17 [ABSTRACT FROM AUTHOR]

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We conducted a randomized, double-blind, placebo-controlled, single-patient (N = 1) trial to evaluate the efficacy of zolpidem in a 48-year-old woman with an akinetic mutism. Motor and cognitive examinations and functional imaging were performed. Acute administration of zolpidem markedly improved motor performance and neuropsychological status. Cerebral metabolism (18F-fluorodeoxyglucose positron emission tomography) increased in postrolandic territories and in frontal cortex. Using the H215O positron emission tomography, we found a drug-induced activation in the anterior cingulate and orbitofrontal cortices. Zolpidem induced a transient improvement in motor and cognitive performances. This paradoxical effect could result from an activation of limbic loops modulating motivational processes. Ann Neurol 2007 [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate tolerability and possible neurotrophic effects of growth hormone (GH) in treatment of multiple system atrophy (MSA). In this double-blind pilot study, MSA patients were randomized to recombinant human growth hormone (r-hGH, n = 22), 1 mg every second day (6 months) followed by alternating daily injections of 1 mg and 0.5 mg (6 months), or matched placebo (n = 21). Safety analysis demonstrated no obvious between-group differences. In both groups, there was progressive worsening of Unified Parkinson's Disease Rating Scale total score, which tended to be less in r-hGH-treated patients (12.9% at 6 months, 25.3% at 12 months) than in placebo (17.0% and 35.7%). Similarly, there was a trend to less worsening in Unified MSA Rating Scale total score with r-hGH (13.2% and 21.2%) than with placebo (21.1% and 36.5%). Cardiovascular reflex autonomic testing also tended to show less deterioration with r-hGH than with placebo at 12 months. However, 95% CI did not indicate treatment differences for any efficacy measures. In conclusion, r-hGH administration in MSA patients for up to 1 year appears safe and might influence disease symptoms, signs and, possibly, progression. The results support further studies utilizing higher doses in more patients. © 2007 Movement Disorder Society [ABSTRACT FROM AUTHOR]

The T-cell differentiation antigen, CD4, is expressed by major histocompatibility (MHC) class II restricted I lymphocytes. CD4+CD8+ T cells use their T-cell receptor to recognize foreign antigens in association with MHC class If products (Ia). The association between CD4 expression and restriction by MHC class II products has led to the hypothesis that CD4 may interact with monomorphic determinants of MHC class II molecules. A large body of experimental evidence suggests that CD4 interaction with MHC class II molecules leads to an increase in the binding avidity of T cell-stimulator cell interactions. A direct test for a functional CD4-MHC class II interaction in T-cell activation requires a separate evaluation of CD4-Ia interactions from T-cell receptor (TcR)-antigen (Ag)/Ia recognition. However, a separate evaluation proves difficult since the T-cell receptor and CD4 may interact with the same MHC class II molecule. In this report, we use a T-cell activation protocol where TcR-Ag/Ia recognition is replaced by TcR complex-anti-CD3 antibody interactions. Therefore, the affinity of the TcR complex for its ligand (the anti-CD3 mAb) is independent from MHC expression on target cells and allows a separate evaluation of the role of accessory molecules in T-cell activation. We have analysed the effects of monoclonal anti-MHC class II antibodies on the activation of a CD4 T-cell hybridoma in the absence of its TcR restricting MHC class II molecule (f!Ek) but in the presence of unrelated MHC class II molecules (I-Ed, I-Ad). The data obtained indicate a functional interaction between the CD4 molecule and a non-polymorphic region of the MHC class II product in T-cell triggering. [ABSTRACT FROM AUTHOR]

Fabrication of silicon thin film (TF-Si) solar cells with high throughput on cheap substrates requires both adequate deposition techniqueand suitable substrate. Our approach consists of depositing polycrystalline silicon films with thickness of 10-30 mu m by Rapid Thermal Chemical Vapour Deposition (RT-CVD) onto newly developed mullite ceramics. Compared to alumina, the latter has the advantage that the thermal expansion coefficient can be matched to that of silicon by compositional adjustment. The substrates are elaborated by the tape casting process, enabling continuous production on large size (>/=50 cm width). The polycrystalline silicon thin film with structure p+/p is deposited at atmospheric pressure by RT-CVD, tailoring in-situ the temperature and doping profiles. High deposition rates of 1-5 mum/min are commonly obtained in the temperature range 1000-1200 deg. C. In the present paper, the overall optical, crystalline and electrical features of TF-Si on mullite ceramics are presented. [ABSTRACT FROM AUTHOR]

Polycrystalline silicon thin-film layers were deposited on foreign substrates such as SiO2 , alumina, mullite and graphite. The deposition studies were carried out in a single-wafer, horizontal, rapid thermal chemical vapor phase reactor at temperatures ranging from 900 deg. C to 1250 deg. C at atmospheric pressure. We employed thegas precursor trichlorosilane and the layers were doped with boron from the dopant source trichloroborine rarified in a hydrogen carrier gas. The surface structures and grain sizes of the thin films obtained were evaluated by Nomarski microscopy and scanning electron microscopy characterization methods. X-ray diffraction analyses were used todetermine the preferential crystalline orientations at various operational parameters. Furthermore, electrical properties in terms of Hall mobility and lifetimes of the minority carriers were investigated by means of Van-der-Pauw and photoconductivity decay methods, respectively. Generally, it has been shown that at elevated deposition temperatures maximum grain sizes of 3-20 mum for 10-mum thick layers can befound, depending critically on the type of the substrate. For polycrystalline silicon deposited at 1100 deg. C on silicon dioxide, alumina, and graphite substrates, a preferred crystallographic orientation of (220) was observed, implying columnar grain structures. [ABSTRACT FROM AUTHOR]