bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microcrystalline silicon n‐i‐p solar cells prepared with microcrystalline silicon oxide (μc‐SiOx:H) n‐layer
Authors: Smirnov Vladimir , Böttler Wanjiao , Lambertz Andreas , Wang Haiyan , Carius Reinhard , Finger Friedhelm 
Published: February 2010

AbstractN‐type hydrogenated microcrystalline silicon oxide (μc‐SiOx:H) layers were used as window layers in n‐side illuminated microcrystalline silicon n–i–p solar cells. Optical, electrical and structural properties of μc‐SiOx:H films were investigated by Photothermal Deflection Spectroscopy, conductivity and Raman scattering measurements. μc‐SiOx:H layers were prepared over a range of carbon dioxide (CO2) flow and film thickness, and the effects on the solar cell performance were investigated. By optimising the μc‐SiOx:H window layer properties, an improved short‐circuit current density of 23.4 mA/cm2 is achieved, leading to an efficiency of 8.0% for 1μm thick absorber layer and Ag back contact. The correlation between cell performance and μc‐SiOx:H layer properties is discussed. The results are compared to the performance of solar cells prepared with alternative optimised window layers. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab initio calculations and the effect of atomic substitution in the Raman spectra of As(Sb,Bi)2S3 films
Authors: Kondrat Olexandr , Popovich Natalija , Holomb Roman , Mitsa Volodimir , Petrachenkov Olexandr , Koós Margit , Veres Miklos 
Published: February 2010

AbstractThe comparative analysis of the calculated and experimental Raman spectra of non‐crystalline As2S3, Bi2S3 and Sb2S3 films (i.e. with exchanging As to Sb, Bi) obtained by flash evaporation on glassy and silicon substrates was performed. The spectra were interpreted and analysed using the results of molecular modelling and ab initio calculations. The structural models used for calculations include both basic building blocks and other types of atomic clusters known for As‐S, Bi‐S, and Sb‐S binary systems. The influence of atomic substitution on the nanostructure of flash evaporated As(Sb,Bi)2S3 films were investigated, observed photo‐induced phenomena and related peculiarities were analysed using results of ab initio calculations and discussed in detail. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microscopic study of carrier transport in the organic semiconductor zinc‐phthalocyanine
Authors: Duarte João Piroto , Alberto Helena Vieira , Vilão Rui César , Gil João M. , Weidinger Alois , Campos Nuno Ayres de 
Published: February 2010

AbstractNominally undoped zinc‐phthalocyanine (ZnPc) was investigated using Muon Spin Rotation (μSR) to probe microscopic carrier transport properties. The study focused on the relaxation of the positive muon's polarisation produced by spin‐flip scattering with charge carriers. An energy of 71(8) meV was found for the temperature activation of carrier jumps, a value that does not match the activation energies known in ZnPc from electrical measurements, and that was attributed to a fast transport component in this material. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New developments in the fabrication of amorphous silicon photovoltaic modules on very large 2.60 m × 2.20 m glass
Authors: Vetter Michael , Borrajo Jacinto P. , Andreu Jordi 
Published: February 2010

AbstractThe fabrication of photovoltaic thin film modules based on hydrogenated amorphous silicon (a‐Si:H) technology on very large float glass is presented. In high volume manufacture of about 900 modules/day production present an average power of about 105 W ±5 W (initial state, 1.43 m2 modules). Light‐induced degradation (LID) of modules results in an average power of about 85±2 W after about 500 kWh of degradation. Degradation of the fill factor (FF) of current voltage curves under illumination is the main contributor to degradation reducing from about 70% to 60% (artificial light). The dependency of the power in the initial and in the degraded state on the intrinsic layer thickness of the pin‐structure is investigated. Thicker intrinsic layer results in higher initial power, however also the degradation rate is higher resulting in very similar power of all modules in the degradation state. LID is performed in in‐door conditions under metal‐halogen lamp light and in outdoor conditions with sun‐light. Under outdoor conditions the degraded state of the modules is not stable, but depends on the season, resulting in lower power in winter months and higher power in summer months. Main contributor to this effect is the change of short circuit current. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of metal contact properties on thermal annealed PECVD SiC thin films for MEMS applications
Authors: Oliveira Alessandro R. , Pereyra Inés , Carreño Marcelo N. P. 
Published: February 2010

AbstractThe investigation of metal contact properties of thermal annealed PECVD n‐type SiC thin films for micro‐electromechanical system (MEMS) is reported. The PECVD SiC films were annealed at 1200 °C during 2 hours to obtain poly 3C‐SiC, which is evidenced by the presence of (111) plane of 3C–SiC crystalline phase in the X‐ray diffraction (XRD) pattern and by strong and narrow Lorentzian SiC stretching peak in the FTIR spectra. Hall Effect measurements at room temperature demonstrate that these annealed phosphorus doped films are n‐type semiconductor with donor concentration of 6 × 1019 cm–3. The studied metals were titanium, aluminum and nickel. The metal to poly‐SiC contact were studied using the TLM technique. The three metals exhibited excellent I‐V linearly and showed ohmic characteristics at room temperature. In the best case, a specific resistance of 6 × 10–4 Ωcm2 was obtained for nickel contacts. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallographic orientation dependent etching of graphene layers
Authors: Nemes–Incze Péter , Magda Gábor , Kamarás Katalin , Biró László Péter 
Published: February 2010

AbstractGraphene has gripped the scientific community ever since its discovery in 2004, with very promising electronic properties and hopes to integrate graphene into nanoelectronic devices. For graphene to make its way into electronic devices, two major obstacles have to be overcome: reproducible preparation of large area graphene samples and patterning techniques to obtain functional components. In this paper we present a graphene etching technique, which is crystallographic orientation selective and allows for the patterning of graphene layers using a chemical reduction process. The process involves the reduction of the SiO2 support by the carbon in the graphene itself. This reaction only occurs at the sample edges and does not result in the degradation of the graphene crystal lattice itself. However, we have observed evidence of strong hole doping in our etched samples.This etching technique opens up new possibilities in graphene patterning and modification. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The correlation structure of longitudinal measurements of vision in patients with macular degeneration
Authors: Burzykowski Tomasz , Buyse M. 
Published: February 2010

AbstractBackground: In age‐related macular degeneration (ARMD) trials, the FDA‐approved endpoint is the loss (or gain) of at least three lines of vision as compared to baseline. The use of such a response endpoint entails a potentially severe loss of information. A more efficient strategy could be obtained by using longitudinal measures of the change in visual acuity. In this paper we investigate, by using data from two randomized clinical trials, the mean and variance–covariance structures of the longitudinal measurements of the change in visual acuity.Methods: Individual patient data were collected in 234 patients in a randomized trial comparing interferon‐α with placebo and in 1181 patients in a randomized trial comparing three active doses of pegaptanib with sham. A linear model for longitudinal data was used to analyze the repeated measurements of the change in visual acuity.Results: For both trials, the data were adequately summarized by a model that assumed a quadratic trend for the mean change in visual acuity over time, a power variance function, and an antedependence correlation structure. The power variance function was remarkably similar for the two datasets and involved the square root of the measurement time.Conclusions: The similarity of the estimated variance functions and correlation structures for both datasets indicates that these aspects may be a genuine feature of the measurements of changes in visual acuity in patients with ARMD. The feature can be used in the planning and analysis of trials that use visual acuity as the clinical endpoint of interest. Copyright © 2010 John Wiley & Sons, Ltd.
Individual and combined influence of El Niño–Southern Oscillation and Indian Ocean Dipole on the Tropospheric Biennial Oscillation
Authors: Pillai Prasanth A. , Mohankumar K. 
Published: February 2010

AbstractTropospheric biennial oscillation (TBO) is the tendency of a strong monsoon to be followed by a weaker one and vice versa. It involves both oceanic and atmospheric processes in the tropical Indian and Pacific Ocean regions. The present study analyses the effect of dynamical processes of the Indian and Pacific Oceans like the Indian Ocean Dipole (IOD) and El Niño–Southern Oscillation (ENSO) on the TBO. The 200 hPa velocity potential, 850 hPa zonal wind and sea‐surface temperature datasets obtained from NCEP/NCAR reanalysis for the period 1950–2006 are used for the study of the TBO. The IOD and TBO have both in‐phase (positive/negative IOD with positive/negative TBO) and out‐of‐phase (positive/negative IOD with negative/positive TBO) relationships. On the other hand, La Niña is associated with the positive phase of TBO and El Niño with the negative phase. In the presence of El Niño (La Niña), positive (negative) IOD is associated with negative (positive) TBO and in the absence of ENSO, positive (negative) IOD is associated with positive (negative) phase of TBO. When ENSO is associated with TBO, it tends to dominate the biennial transition irrespective of IOD. In‐phase Indian to Australian monsoon transition of TBO is controlled by ENSO. IOD–TBO association is strong and significant in the absence of ENSO only. The biennial reversal is confined to the Indian Ocean in the TBO cycle associated with IOD only. Thus IOD can be considered as the local forcing for the biennial monsoon cycle, and ENSO the remote effect. Copyright © 2010 Royal Meteorological Society
Blinded sample size reestimation with count data: Methods and applications in multiple sclerosis
Authors: Friede Tim , Schmidli Heinz 
Published: February 2010

AbstractSample size estimation in clinical trials depends critically on nuisance parameters, such as variances or overall event rates, which have to be guessed or estimated from previous studies in the planning phase of a trial. Blinded sample size reestimation estimates these nuisance parameters based on blinded data from the ongoing trial, and allows to adjust the sample size based on the acquired information. In the present paper, this methodology is developed for clinical trials with count data as the primary endpoint. In multiple sclerosis such endpoints are commonly used in phase 2 trials (lesion counts in magnetic resonance imaging (MRI)) and phase 3 trials (relapse counts). Sample size adjustment formulas are presented for both Poisson‐distributed data and for overdispersed Poisson‐distributed data. The latter arise from sometimes considerable between‐patient heterogeneity, which can be observed in particular in MRI lesion counts. The operation characteristics of the procedure are evaluated by simulations and recommendations on how to choose the size of the internal pilot study are given. The results suggest that blinded sample size reestimation for count data maintains the required power without an increase in the type I error. Copyright © 2010 John Wiley & Sons, Ltd.
Transforming Growth Factor-β and Notch Signaling Mediate Stem Cell Differentiation into Smooth Muscle Cells
Authors: Kurpinski Kyle , Lam Hayley , Chu Julia , Wang Aijun , Kim Ahra , Tsay Eric , Agrawal Smita , Schaffer David V. , Li Song 
Published: February 2010

Abstract
The differentiation of stem cells into smooth muscle cells (SMCs) plays an important role in vascular development and remodeling. In addition, stem cells represent a potential source of SMCs for regenerative medicine applications such as constructing vascular grafts. Previous studies have suggested that various biochemical factors, including transforming growth factor-β (TGF-β) and the Notch pathway, may play important roles in vascular differentiation. However, the interactions of these two signaling pathways in the differentiation of bone marrow mesenchymal stem cells (MSCs) have not been clearly defined. In this study, we profiled the gene expression in MSCs in response to TGF-β, and showed that TGF-β induced Notch ligand Jagged 1 (JAG1) and SMC markers, including smooth muscle α-actin (ACTA2), calponin 1 (CNN1), and myocardin (MYOCD), which were dependent on the activation of SMAD3 and Rho kinase. In addition, knocking down JAG1 expression partially blocked ACTA2 and CNN1 expression and completely blocked MYOCD expression, suggesting that JAG1 plays an important role in TGF-β-induced expression of SMC markers. On the other hand, the activation of Notch signaling induced the expression of SMC markers in MSCs and human embryonic stem cells (hESCs). Notch activation in hESCs also resulted in an increase of neural markers and a decrease of endothelial markers. These results suggest that Notch signaling mediates TGF-β regulation of MSC differentiation and that Notch signaling induces the differentiation of MSCs and hESCs into SMCs, which represents a novel mechanism involved in stem cell differentiation.
The impact of a classroom intervention on grade 10 students' argumentation skills, informal reasoning, and conceptual understanding of science
Authors: Venville Grady J. , Dawson Vaille M. 
Published: February 2010

AbstractThe literature provides confounding information with regard to questions about whether students in high school can engage in meaningful argumentation about socio‐scientific issues and whether this process improves their conceptual understanding of science. The purpose of this research was to explore the impact of classroom‐based argumentation on high school students' argumentation skills, informal reasoning, and conceptual understanding of genetics. The research was conducted as a case study in one school with an embedded quasi‐experimental design with two Grade 10 classes (n = 46) forming the argumentation group and two Grade 10 classes (n = 46) forming the comparison group. The teacher of the argumentation group participated in professional learning and explicitly taught argumentation skills to the students in his classes during one, 50‐minute lesson and involved them in whole‐class argumentation about socio‐scientific issues in a further two lessons. Data were generated through a detailed, written pre‐ and post‐instruction student survey. The findings showed that the argumentation group, but not the comparison group, improved significantly in the complexity and quality of their arguments and gave more explanations showing rational informal reasoning. Both groups improved significantly in their genetics understanding, but the improvement of the argumentation group was significantly better than the comparison group. The importance of the findings are that after only a short intervention of three lessons, improvements in the structure and complexity of students' arguments, the degree of rational informal reasoning, and students' conceptual understanding of science can occur. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 952–977, 2010
Exploring identities to deepen understanding of urban high school students' sexual health decision‐making
Authors: Brotman Jennie S. , Mensah Felicia Moore , Lesko Nancy 
Published: February 2010

AbstractSexual health is a controversial science topic that has received little attention in the field of science education, despite its direct relevance to students' lives and communities. Moreover, research from other fields indicates that a great deal remains to be learned about how to make school learning about sexual health influence the real‐life choices of students. In order to provide a more nuanced understanding of young people's decision‐making, this study examines students' talk about sexual health decision‐making through the lens of identities. Qualitative, ethnographic research methods with twenty 12th grade students attending a New York City public school are used to illustrate how students take on multiple identities in relation to sexual health decision‐making. Further, the study illustrates how these identities are formed by various aspects of students' lives, such as school, family, relationships, and religion, and by societal discourses on topics such as gender, individual responsibility, and morality. The study argues that looking at sexual health decision‐making—and at decision‐making about other controversial science topics—as tied to students' identities provides a useful way for teachers and researchers to grasp the complexity of these decisions, as a step toward creating curriculum that influences them. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47:742–762, 2010
Holzoberflächenmodifikation mittels Atmosphärendruckplasma
Authors: Avramidis Georg , Nothnick Evelyn , Wolkenhauer Arndt , Militz Holger , Viöl Wolfgang 
Published: February 2010

AbstractIm vorliegenden Artikel werden plasmatechnische, analytische und anwendungsrelevante Aspekte der Plasmabehandlung von Holz und Holzwerkstoffen vorgestellt. Anhand von Oberflächenenergiebestimmungen und Adhäsionstests wird gezeigt, dass sich die Oberflächen von Holz und Holzwerkstoffen für spezifische Anwendungen verändern lassen. So können unter Verwendung eines Luftplasmas anwendungstechnisch interessante Oberflächeneigenschaften im Hinblick auf eine nachfolgende Beschichtung bzw. Verklebung gezielt generiert werden. Mit oberflächenenergetischen Untersuchungen von Holz und Holzwerkstoffen konnte nach einer Plasmabehandlung ein signifikant erhöhter polarer Anteil der Oberflächenenergie nachgewiesen werden. Rasterkraftmikroskopische Untersuchungen von Holzkompositen zeigen, dass eine Plasmabehandlung unter Verwendung von Umgebungsluft eine Abrasion und veränderte Oberflächenrauhigkeit bewirkt. Zug‐ und Schertests an plasmabehandelten beschichteten oder verklebten Holzwerkstoffen weisen eine deutlich erhöhte Haftfestigkeit auf.
El Niño and our future climate: where do we stand?
Authors: Vecchi Gabriel A. , Wittenberg Andrew T. 
Published: February 2010

AbstractEl Niño and La Niña comprise the dominant mode of tropical climate variability: the El Niño and Southern Oscillation (ENSO) phenomenon. ENSO variations influence climate, ecosystems, and societies around the globe. It is, therefore, of great interest to understand the character of past and future ENSO variations. In this brief review, we explore our current understanding of these issues. The amplitude and character of ENSO have been observed to exhibit substantial variations on timescales of decades to centuries; many of these changes over the past millennium resemble those that arise from internally generated climate variations in an unforced climate model. ENSO activity and characteristics have been found to depend on the state of the tropical Pacific climate system, which is expected to change in the 21st century in response to changes in radiative forcing (including increased greenhouse gases) and internal climate variability. However, the extent and character of the response of ENSO to increased in greenhouse gases are still a topic of considerable research, and given the results published to date, we cannot yet rule out possibilities of an increase, decrease, or no change in ENSO activity arising from increases in CO2. Yet we are fairly confident that ENSO variations will continue to occur and influence global climate in the coming decades and centuries. Changes in continental climate, however, could alter the remote impacts of El Niño and La Niña. Copyright © 2010 John Wiley & Sons, Ltd.This article is categorized under:

Paleoclimates and Current Trends > Detection and Attribution
Speciation of antimony in polyethylene terephthalate bottles
Authors: Martin Ronald R. , Shotyk William S. , Naftel Steven J. , Ablett James M. , Northrup Paul 
Published: February 2010

AbstractAntimony contamination has been reported in drinking water from polyethylene terephthalate (PET) bottles. Micro‐X‐ray fluorescence (XRF) analysis has been used to identify the distribution and chemical form of residual antimony used as a catalyst in the manufacture of PET bottles. The results are consistent with clusters of Sb(III) having dimensions of the order of tens of micrometers, clearly showing the ability of synchrotron radiation analyses to both map elemental distribution and determine oxidation state. Copyright © 2010 John Wiley & Sons, Ltd.
Tumor Protein p53‐Induced Nuclear Protein (TP53INP1) Expression in Medullary Thyroid Carcinoma: A Molecular Guide to the Optimal Extent of Surgery?
Authors: Taïeb D. , Giusiano S. , Sebag F. , Marcy M. , de Micco C. , Palazzo F. F. , Dusetti N. J. , Iovanna J. L. , Henry J. F. , Garcia S. , Taranger‐Charpin Colette 
Published: February 2010

AbstractBackgroundMedullary thyroid cancer (MTC) is characterized by early regional lymph node metastasis, the presence of which represents a critical obstacle to cure. At present no molecular markers have been successfully integrated into the clinical care of sporadic MTC. The present study was designed to evaluate TP53INP1 expression in MTC and to assess its ability to guide the surgeon to the optimal extent of surgery performed with curative intent.MethodsThirty‐eight patients with sporadic MTC were evaluated. TP53INP1 immunoexpression was studied on embedded paraffin material and on cytological smears.ResultsTP53INP1 was expressed in normal C cells, in C‐cell hyperplasia, and in 57.9% of MTC. It was possible to identify two groups of MTC according to the proportion of TP53INP1 expressing tumor cells: group 1 from 0% to <50% and group 2 from 50% to 100% of positive cells. Patients with a decreased expression of TP53INP1 (group 1) had a lower rate of nodal metastasis (18.8% versus 63.4% in group 2; P = 0.009), with only minimal lymph node involvement per N1 patient (2.7% of positive lymph nodes versus 22.9%; P < 0.001) and better outcomes (100% of biochemical cure versus 55.5%; P < 0.001). Patients with distant metastases were only observed in group 2. Cytological samples exhibit similar results to their embedded counterparts.ConclusionsTP53INP1 immunoexpression appears to be a clinical predictor of lymph node metastasis in MTC. The evaluation of TP53INP1 expression may guide the extent of lymph node dissection in the clinically node‐negative neck. These findings require prospective validation.