Low temperature‐coefficient for solar cells processed from solar‐grade silicon purified by metallurgical route

This study is dedicated to the temperature (T)‐variation of the photovoltaic performances of solar cells made from solar‐grade silicon directly purified by metallurgical route (SoG_M‐Si). Experimental results were systematically compared with those for standard electronic‐grade silicon (EG‐Si) solar cells. We showed that the conversion efficiency (η) of SoG_M‐Si cells decreases much less when T increases than the η of EG‐Si cells. This major difference is due to a strong increase with T of the short‐circuit current density (J_sc) of the SoG_M‐Si solar cells. We showed that this a priori unexpected result could be described and explained by numerical simulations, by taking into account the main particularities of SoG_M‐Si: dopant compensation, moderate minority carrier diffusion length and larger amount of boron–oxygen complexes. These results are significant since T of a solar module under illumination being generally higher than 25°C, modules made from low‐cost SoG_M‐Si cells should have performances closer to those of standard EG‐Si solar panels. Copyright © 2011 John Wiley & Sons, Ltd.     

Reconstruction of nonuniformly sampled images in spline spaces.

This paper presents a novel approach to the reconstruction of images from nonuniformly spaced samples. This problem is often encountered in digital image processing applications. Nonrecursive video coding with motion compensation, spatiotemporal interpolation of video sequences, and generation of new views in multicamera systems are three possible applications. We propose a new reconstruction algorithm based on a spline model for images. We use regularization, since this is an ill-posed inverse problem. We minimize a cost function composed of two terms: one related to the approximation error and the other related to the smoothness of the modeling function. All the processing is carried out in the space of spline coefficients; this space is discrete, although the problem itself is of a continuous nature. The coefficients of regularization and approximation filters are computed exactly by using the explicit expressions of B-spline functions in the time domain. The regularization is carried out locally, while the computation of the regularization factor accounts for the structure of the nonuniform sampling grid. The linear system of equations obtained is solved iteratively. Our results show a very good performance in motion-compensated interpolation applications.     

An end‐to‐end alternative to TCP PEPs: Initial Spreading,a TCP fast start‐up mechanism

While Transmission Control Protocol (TCP) Performance Enhancing Proxy (PEP) solutions have long been undisputed to solve the inherent satellite problems, the improvement of the regular end‐to‐end TCP congestion avoidance algorithms and the recent emphasis on the PEPs drawbacks have opened the question of the PEPs sustainability. Nevertheless, with a vast majority of Internet connections shorter than ten segments, TCP PEPs continue to be required to counter the poor efficiency of the end‐to‐end TCP start‐up mechanisms. To reduce the PEPs dependency, designing a new fast start‐up TCP mechanism is therefore a major concern. But, while enlarging the Initial Window (IW) up to ten segments is, without any doubt, the fastest solution to deal with a short‐lived connection in an uncongested network, numerous researchers are concerned about the impact of the large initial burst on an already congested network. Based on traffic observations and real experiments, Initial Spreading has been designed to remove those concerns whatever the load and type of networks. It offers performance similar to a large IW in uncongested network and outperforms existing end‐to‐end solutions in congested networks. In this paper, we show that Initial Spreading, taking care of the satellite specificities, is an efficient end‐to‐end alternative to the TCP PEPs. Copyright © 2015 John Wiley & Sons, Ltd.     

Polymerization of β-butyrolactone initiated with Al(OiPr)3

Polymerization of β-butyrolactone has been studied in toluene with Al(OⁱPr)₃ as an initiator. The ring-opening polyaddition proceeds through a coordination–insertion mechanism at a very low rate. Well defined α-isopropylester, ω-hydroxy poly(β-butyrolactone)s (PBL) are formed with a narrow molecular weight distribution at low monomer-to-initiator molar ratios, When this ratio is higher (ca. 170), a competition occurs between propagation and side reactions, i.e. elimination, inter- and intra-molecular transesterifications and thermal degradation, which is responsible for a loss of control of the PBL molecular charcteristics. The addition of a Lewis base (1 equivalent of nicotine/Al) to the Al-alkoxide initiator has no significant effect on the polymerization rate, although the chain microstructure is deeply affected since predominantly syndiotactic PBL chains are formed (63% syndio-diads) in contrast to a completely atactic polymer in the absence of nicotine.     

Melt‐stable poly(1,4‐dioxan‐2‐one) (co)polymers by ring‐opening polymerization via continuous reactive extrusion

Bulk polymerization of ?‐caprolactone (CL), 1,4‐dioxan‐2‐one (PDX), and mixtures of PDX and CL was carried out by initiation with Al(O^secBu)₃ in a co‐rotating twin‐screw extruder through a fast single‐step process. Both homopolymerizations and copolymerization of PDX and CL proceed very rapidly and reach almost complete (co)‐ monomer(s) conversion as soon as 8 mol% of CL are added in the feed. Even though poly(1,4‐dioxan‐2‐one) (PPDX) is known to thermally degrade mainly through unzipping depolymerization promoted from the hydroxyl end‐groups and yielding PDX monomer, it turns out that the thermal stability of PPDX chains is substantially improved by the copolymerization of PDX with limited amounts of CL. Interestingly, DSC analysis of the so‐obtained P(PDX‐co‐CL) copolymers has demonstrated that a CL molar fraction as high as 11 mol% does not prevent the crystallization of the resulting copolymer, which retains a melting temperature close to 95°C. This last observation has been explained by the formation of a blocky‐like copolymer structure, in which short PPDX and PCL sequences are randomly distributed. POLYM. ENG. SCI., 45:622–629, 2005. © 2005 Society of Plastics Engineers.     

Determinants of transmission success of individual clones from mixed-clone infections of the rodent malaria parasite, Plasmodium chabaudi

PURPOSE: To compare the permeation characteristics of amide bond-containing HIV-1 protease inhibitors and their pyrrolinone-containing counterparts across Caco-2 cell monolayers, a model of the intestinal mucosa. METHODS: Transepithelial transport and cellular uptake of three pairs of amide bond-containing and pyrrolinone-based peptidomimetics were assessed in the presence and absence of cyclosporin A using the Caco-2 cell culture model. The potential of the peptidomimetics to interact with biological membranes was estimated by IAM chromatography. RESULTS: In the absence of cyclosporin A, apical (AP) to basolateral (BL) flux of all compounds studied was less than the flux determined in the opposite direction (i.e., BL-to-AP). The ratio of the apparent permeability coefficients (Papp) calculated for the BL-to-AP and AP-to-BL transport (P(BL-->AP)/P(AP-->BL)) varied between 1.7 and 36.2. When individual pairs were ompared, P(BL-->AP)/P(AP-BL) ratios of the pyrrolinone-containing compounds were 1.5 to 11.5 times greater than those determined for the amide bond-containing analogs. Addition of 25 microM cyclosporin A to the transport buffer reduced the P(BL-->AP)/P(AP-->BL) ratios for all protease inhibitors to a value close to unity. Under these conditions, the amide bond-containing peptidomimetics were at least 1.6 to 2.8 times more able to permeate Caco-2 cell monolayers than were the pyrrolinone-containing compounds. The intrinsic uptake characteristics into Caco-2 cells determined in the presence of 25 microM cyclosporin A were slightly greater for the amide bond-containing protease inhibitors than for the pyrrolinone-containing analogs. These uptake results are consistent with the transepithelial transport results determined across this in vitro model of the intestinal mucosa. CONCLUSIONS: The amide bond-containing and pyrrolinone-based peptidomimetics are substrates for apically polarized efflux systems present in Caco-2 cell monolayers. The intrinsic permeabilities of the amide bond-containing protease inhibitors are slightly greater than the intrinsic permeabilities of the pyrrolinone-based analogs through Caco-2 cell monolayers.     

Global functioning of inpatients with obsessive-compulsive disorder, schizophrenia, and major depression

In April and May 1996, two cases of PDA ligation were performed firstly in Turkey by the method of video assisted thoracoscopic surgery (VATS) in Dokuz Eylül Medical Faculty, Thoracic and Cardiovascular Surgery Department. There was not any complication in these patients in the postoperative period and they were discharged on the second day in symptom-free condition by the detection of closed ductus in their echocardiographic examination. Between February 1993 and October 1996, a total of 46 patients have undergone interventional application by VATS. While in six of these patients the procedure could not be manipulated because of massive pleural fibrosis, there was no mortality or morbidity among the patients, and they were discharged on average on the second day. The ratio of complications, such as bleeding, air leak, arrhythmia and empyema are so low in these operations, and hospital stay, with return to work time are shorter than with the open technique.     

The Use of Pro-Angiogenic and/or Pro-Hypoxic miRNAs as Tools to Monitor Patients with Diffuse Gliomas

IDH (isocitrate dehydrogenase) mutation, hypoxia, and neo-angiogenesis, three hallmarks of diffuse gliomas, modulate the expression of small non-coding RNAs (miRNA). In this paper, we tested whether pro-angiogenic and/or pro-hypoxic miRNAs could be used to monitor patients with glioma. The miRNAs were extracted from tumoral surgical specimens embedded in the paraffin of 97 patients with diffuse gliomas and, for 7 patients, from a blood sample too. The expression of 10 pro-angiogenic and/or pro-hypoxic miRNAs was assayed by qRT-PCR and normalized to the miRNA expression of non-tumoral brain tissues. We confirmed in vitro that IDH in hypoxia (1% O₂, 24 h) alters pro-angiogenic and/or pro-hypoxic miRNA expression in HBT-14 (U-87 MG) cells. Then, we reported that the expression of these miRNAs is (i) strongly affected in patients with glioma compared to that in a non-tumoral brain; (ii) correlated with the histology/grade of glioma according to the 2016 WHO classification; and (iii) predicts the overall and/or progression-free survival of patients with glioma in univariate but not in a multivariate analysis after adjusting for sex, age at diagnosis, and WHO classification. Finally, the expression of miRNAs was found to be the same between the plasma and glial tumor of the same patient. This study highlights a panel of seven pro-angiogenic and/or pro-hypoxic miRNAs as a potential tool for monitoring patients with glioma.