bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoreflectance spectroscopy of the band bending and the energy gap for Mg‐doped InN layers
Authors: Kudrawiec R. , Suski T. , Misiewicz J. , Muto D. , Nanishi Y. 
Published: February 2009

AbstractPhotoreflectance (PR) spectroscopy has been applied to investigate the band bending (built‐in electric field) and the energy gap for Mg‐doped InN layers with various Mg concentrations (4.0‐7.3 × 1020 cm–3). A broad PR resonance followed by the Franz‐Keldysh oscillation, which is typical of the band‐to‐band absorption in the sample region with strong band bending, has been observed at the energy of ∼0.66‐0.7 eV. The region of strong band bending in InN:Mg layers results from the Fermi level pinning at the energy range i) above the conduction band at the sample surface and ii) close to the valence band inside InN:Mg layer due to Mg‐doping. The built‐in electric field in this region has been estimated from the Franz‐Keldysh oscillation to be ∼0.6‐0.8 MV/cm. In addition, it has been observed that the energy gap of InN:Mg is reduced from about 0.70 eV to 0.66 eV with the increase in Mg concentration from 4 to 7.3 × 1020 cm–3. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlation of surface morphology and photoluminescence fluctuation in green light emitting InGaN/GaN quantum wells
Authors: Danhof Julia , Vierheilig Clemens , Schwarz Ulrich T. , Meyer Tobias , Peter Matthias , Hahn Berthold , Maier Markus , Wagner Joachim 
Published: February 2009

AbstractFor InGaN/GaN multiple quantum well structures a correlation of surface morphology and photoluminescence fluctuations has been established by comparing atomic force microscopy images with PL measurements of the same area. The two analyzed samples were grown simultaneously, but on different substrates and therefore with different dislocation densities. Their PL peak wave lengths lie in between 510 nm and 520 nm. Meandering structures observed for both samples by micro– photoluminescence (μPL) are in the case of the sample on GaN substrate not created by threading dislocations. Threading dislocations may influence the development of meandering structures but do not cause them (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polar and nonpolar HVPE GaN substrates: impact of doping on the structural, electrical and optical characteristics
Authors: Paskova T. , Preble E. A. , Hanser A. D. , Evans K. R. , Kröger R. , Paskov P. P. , Cheng A. J. , Park M. , Grenko J. A. , Johnson M. A. L. 
Published: February 2009

AbstractPolar and nonpolar bulk GaN substrates with low defect density and high structural and optical quality are demonstrated. The effect of doping by silicon, oxygen and iron within moderate doping levels on the properties of the polar GaN substrates was found uncompromised, as confirmed by high resolution X‐ray diffraction and low temperature photoluminescence spectroscopy. In contrast, the lattice parameters were affected significantly, which has to be considered in the subsequent homoepitaxial device growth. The boule growth and respectively the nonpolar substrate homogeneity were found to be hampered by the doping, due to surface microcracking and higher impurity incorporation, while n‐type undoped nonpolar substrates were demonstrated of superior quality. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vertically‐stacked color‐tunable LEDs
Authors: Hui K. N. , Lai P. T. , Choi H. W. 
Published: February 2009

AbstractLight‐emitting diodes with vertical stacking geometry were fabricated and characterized. Color‐tunable emission and white‐light emission has been demonstrated in Stacked‐LED (SLED). Emissions of different colors, ranging from green‐blue, to pink‐purple, to yellow‐orange and white light emission have be achieved by adjusting the relative intensity of two or three individual emission bands, which in turn are controlled by adjusting voltage supply. Compared to conventional lateral side‐by‐side geometry, the shift of white color chromaticity with respect to viewing angles is less in the case of SLED device. The farthest shift of white CIE coordinate point away from the pure white CIE coordinate is (0.29, 0.29) in SLED compared to (0.37, 0.35) in the commerical available lateral packaged structure. This vertically‐stacked LED is poised to open new frontiers in high performance color‐tunable LEDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micro‐structural anisotropy of a‐plane GaN analyzed by high resolution X‐ray diffraction
Authors: Wieneke Matthias , Bläsing Jürgen , Dadgar Armin , Veit Peter , Metzner Sebastian , Bertram Frank , Christen Jürgen , Krost Alois 
Published: February 2009

AbstractNonpolar a‐plane GaN films were grown on r‐plane sapphire by metal‐organic vapour phase epitaxy. Conventionally grown samples exhibit high dislocation densities, as basal stacking faults and partial dislocations. To reduce the defect density in‐situ SiN nanomasks were used. In high resolution X‐ray diffraction ω‐scans the full width of half maximum of the symmetric GaN (11‐20) reflection is azimuthally dependent on the in‐plane beam orientation. By measuring several higher order reflections the causes of broadening, the rotational disorder of the crystallites, and the coherent scattering length parallel to the in‐plane beam orientation are analyzed by a graphical separation known as Williamson‐Hall‐Plot. In addition the micro‐structural properties of the grown samples were investigated by transmission electron microscopy and cathodoluminescence. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain engineering of AlGaN‐GaN HFETs grown on 3 inch 4H‐SiC
Authors: Brunner Frank , Reentilä Outi , Würfl Joachim , Weyers Markus 
Published: February 2009

AbstractIn this work strain evolution during MOVPE of AlGaN/GaN HFET structures on 3 inch SiC substrates is investigated in‐situ and related to properties of the initial AlN wetting layer. It is shown that the density of pits on the AlN surface depending on growth conditions influences GaN nucleation and consequential grain coalescence and stress incorporation. Optimization of the strain and material quality of the GaN layer is demonstrated without degrading the semi‐insulating properties of the HFET buffer. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In silico Prediction of Androgenic and Nonandrogenic Compounds Using Random Forest
Authors: Li Yan , Wang Yonghua , Ding Jun , Wang Yuan , Chang Yaqing , Zhang Shuwei 
Published: February 2009

AbstractThe purpose of the present study was to develop in silico models allowing for a reliable prediction of androgenic and nonandrogenic compounds based on a large diverse dataset of 205 compounds. As a new classification method, the Random Forest (RF) was applied, its performance to classify these compounds in terms of their Quantitative Structure–Activity Relationships (QSAR) was evaluated and also compared with the widely used Partial Least Squares (PLS) analysis for the dataset. The predictive power of these methods was verified with five‐fold cross‐validation and an independent test set. For the RF model, the prediction accuracies of the androgenic and nonandrogenic compounds are 81.0 and 77.0% for cross‐validation, respectively, averaging 87.3% of correctly classified compounds in the external tests. The PLS is slightly weak, showing an average prediction accuracy of 75 and 74.7% for the cross‐validation and external validation, respectively. Our analysis demonstrates that RF is a powerful tool capable of building models for the data and should be valuable for virtual screening of androgen receptor‐binding ligands.
Influence of Changes in 2‐D Chemical Structure Drawings and Image Formats on the Prediction of Biological Properties Using MIA‐QSAR
Authors: Goodarzi Mohammad , Freitas Matheus P. , Ferreira Eric B. 
Published: February 2009

AbstractMultivariate Image Analysis Applied to Quantitative Structure–Activity Relationships (MIA‐QSAR) has been recently implemented as a method to model and predict biological activities of drug‐like compounds. This method is based on the treatment of 2‐D chemical structures, which can be built using specific packages for chemical drawing. These chemical structures correlate with the corresponding bioactivities through descriptors, which are pixels (binaries) of the 2‐D images; the variable moiety of chemical structures (substituent groups) explains the variance in the bioactivities column vector of a series of compounds. Thus, the way in which chemical structures are drawn (font type and size, representation of chemical groups, format in which images are saved) should influence the results of prediction. This work reports the statistics of prediction for a case study, a series of anti‐HIV compounds, and reveals that the results of prediction is independent of the way in which molecules are drawn.
ChemGPS‐NP Mapping of Chemical Compounds for Prediction of Anticancer Mode of Action
Authors: Rosén Josefin , Rickardson Linda , Backlund Anders , Gullbo Joachim , Bohlin Lars , Larsson Rolf , Gottfries Johan 
Published: February 2009

AbstractA combined graph describing the growth inhibition values from a number of human cancer cell lines represents an activity profile for a compound. The fact that compounds with similar activity profiles often show similar Mode of Action (MOA) has frequently been used in prediction of MOA. Obtaining the profiles is demanding with respect to both time and resources. Therefore, as a work and time efficient alternative, we explore the central premise of medicinal chemistry that structurally similar molecules often have similar biological activity. In this study we investigate correlations between chemical structure and MOA, and subsequently use this as a complementing basis for prediction. The correlations between MOA and activity profile on one hand and between MOA and chemical structure on the other were analyzed for anticancer agents, classified with regard to MOA, using Principal Component Analysis (PCA), chemographic mapping with ChemGPS‐NP, and Orthogonal Partial Least Squares Discriminant Analysis (OPLS‐DA). The compounds clustered according to MOA both based on chemical structures and activity profiles. The subsequent validation with external test sets showed that initial PCA scores prediction or chemographic mapping followed by OPLS‐DA could be used for the prediction of MOA as well as identification of novel MOAs in a highly accurate way. An efficient and straight forward procedure for the prediction of MOA of anticancer agents is suggested. With today's resistance problems in cancer therapy, there is a need for new anticancer agents and mechanisms. We believe that the fast initial virtual guidance this procedure implies, especially the novel step using ChemGPS‐NP, could be of general use in early stages of cancer research.
CO2 isotope analyses using large air samples collected on intercontinental flights by the CARIBIC Boeing 767
Authors: Assonov S. S. , Brenninkmeijer C. A. M. , Koeppel C. , Röckmann T. 
Published: February 2009

AbstractAnalytical details for 13C and 18O isotope analyses of atmospheric CO2 in large air samples are given. The large air samples of nominally 300 L were collected during the passenger aircraft‐based atmospheric chemistry research project CARIBIC and analyzed for a large number of trace gases and isotopic composition. In the laboratory, an ultra‐pure and high efficiency extraction system and high‐quality isotope ratio mass spectrometry were used. Because direct comparison with other laboratories was practically impossible, the extraction and measurement procedures were tested in considerable detail. Extracted CO2 was measured twice vs. two different working reference CO2 gases of different isotopic composition. The two data sets agree well and their distributions can be used to evaluate analytical errors due to isotope measurement, ion corrections, internal calibration consistency, etc. The calibration itself is based on NBS‐19 and also verified using isotope analyses on pure CO2 gases (NIST Reference Materials (RMs) and NARCIS CO2 gases). The major problem encountered could be attributed to CO2‐water exchange in the air sampling cylinders. This exchange decreased over the years. To exclude artefacts due to such isotopic exchange, the data were filtered to reject negative δ18O(CO2) values. Examples of the results are given. Copyright © 2009 John Wiley & Sons, Ltd.
Sequence‐Specific HCV RNA Quantification Using the Size‐Dependent Nonlinear Optical Properties of Gold Nanoparticles
Authors: Griffin Jelani , Singh Anant Kumar , Senapati Dulal , Lee Eumin , Gaylor Kevin , Jones‐Boone Jeanette , Ray Paresh Chandra 
Published: February 2009

AbstractThe hepatitis C virus (HCV) is a single‐stranded (ss) RNA virus that is responsible for chronic liver diseases, such as cirrhosis, end‐stage liver disease, and hepatocellular carcinoma. Driven by the need to detect the presence of the HCV viral sequence, herein it is demonstrated for the first time that the nonlinear optical (NLO) properties of gold nanoparticles can be used for screening and quantifying HCV RNA without any modification, with excellent detection limit (80 pM) and selectivity (single base‐pair mismatch). The hyper‐Rayleigh scattering (HRS) intensity increases 25 times when label‐free, 145‐mer, HCV ss‐RNA is hybridized with 400 pM target RNA. The mechanism of HRS intensity change is discussed with experimental evidence for a higher multipolar contribution to the NLO response of gold nanoparticles.
Characterization of Dendritic Cells and Macrophages Generated by Directed Differentiation from Mouse Induced Pluripotent Stem Cells
Authors: Senju Satoru , Haruta Miwa , Matsunaga Yusuke , Fukushima Satoshi , Ikeda Tokunori , Takahashi Kazutoshi , Okita Keisuke , Yamanaka Shinya , Nishimura Yasuharu 
Published: February 2009

AbstractMethods have been established to generate dendritic cells (DCs) from mouse and human embryonic stem (ES) cells. We designated them as ES-DCs and mouse models have demonstrated the induction of anti-cancer immunity and prevention of autoimmune disease by in vivo administration of genetically engineered ES-DCs. For the future clinical application of ES-DCs, the histoincompatibility between patients to be treated and available human ES cells and the ethical concerns associated with human ES cells may be serious obstacles. However, recently developed induced pluripotent stem (iPS) cell technology is expected to resolve these issues. This report describes the generation and characterization of DCs derived from mouse iPS cells. The iPS cell-derived DCs (iPS-DCs) possessed the characteristics of DCs including the capacity of T-cell-stimulation, antigen-processing and presentation and cytokine production. DNA microarray analyses revealed the upregulation of genes related to antigen-presenting functions during differentiation into iPS-DCs and similarity in gene expression profile in iPS-DCs and bone marrow cell-derived DCs. Genetically modified iPS-DCs expressing antigenic protein primed T-cells specific to the antigen in vivo and elicited efficient antigen-specific anti-tumor immunity. In addition, macrophages were generated from iPS cells (iPS-MP). iPS-MP were comparable with bone marrow cell-derived macrophages in the cell surface phenotype, functions, and gene expression profiles.Disclosure of potential conflicts of interest is found at the end of this article.
Harmonizing high performance computing (HPC) with large‐scale complex systems in computational science and engineering
Authors: Chittister Clyde , Haimes Yacov Y. 
Published: February 2009

AbstractThis paper addresses the challenges facing the three different groups within the professional community that support the development of large‐scale scientific and engineering (CSE) software applications. Scientific and engineering systems are but one example of large‐scale complex (LSC) systems. The authors recognize that many of the observations made in this paper also apply to the larger domain. The focus of this paper is restricted to CSE because it is the source of the experiences from which the observations are derived. The first of the groups encompasses the application developers of large‐scale scientific and engineering software systems, especially those requiring high‐performance computing (HPC). The second group covers the HPC software development and run‐time environments. The third consists of the integrators of the first two groups, with a focus on the systems engineers whose task is to bridge the technical and cultural gap between the other two. These challenges reside in several areas, the most important being the educational and cultural backgrounds that are reflected in the knowledge, expertise, and experience of the principals involved. In particular, the cultural gaps and thus the communications and ultimate systems integration challenges are the byproducts of the academic educational system that graduates most software engineers without formal courses in systems engineering, process control, and systems integration. All three groups of challenges are explored individually and in conjunction with each other. Thus, a major problem addressed here is centered in software, because the developers of LSC systems in CSE perceive hardware through the HPC software development environment. Given the unique attributes and characteristics of LSC‐HPC systems, to meet the challenge of the risk modeling, assessment, and management associated with them—at least partially—this paper discusses two complementary approaches: decomposition and hierarchical modeling, which, when applied in conjunction with conventional aggregate modeling methods, offers several promising advantages, especially when dealing with LSC‐HPC systems, and Phantom System Models, used as a real‐time and virtual modeling laboratory for systems integration and risk assessment and management. © 2009 Wiley Periodicals, Inc. Syst Eng
Anxiety disorders in children with Williams syndrome, their mothers, and their siblings: Implications for the etiology of anxiety disorders
Authors: Leyfer Ovsanna , Woodruff-Borden Janet , Mervis Carolyn B. 
Published: February 2009

AbstractThis study examines the prevalence of anxiety disorders in children with Williams syndrome (WS), their sibling closest in age, and their mothers as well as the predictors of anxiety in these groups. The prevalence of anxiety disorders was assessed and compared to that in the general population. Children with WS had a significantly higher prevalence of specific phobia, generalized anxiety disorder (GAD), and separation anxiety in comparison to children in the general population. While mothers had a higher prevalence of GAD than population controls, the excess was accounted for by mothers who had onset after the birth of their WS child. The siblings had rates similar to the general population. This pattern of findings suggests the presence of a gene in the WS region whose deletion predisposes to anxiety disorders. It is also worthwhile to investigate relations between genes deleted in WS and genes previously implicated in anxiety disorders.
Approximate controllability for a system of Schrödinger equations modeling a single trapped ion
Authors: Ervedoza Sylvain , Puel Jean-Pierre 
Published: February 2009

In this article, we analyze the approximate controllability properties for a system of Schrödinger equations modeling a single trapped ion. The control we use has a special form, which takes its origin from practical limitations. Our approach is based on the controllability of an approximate finite dimensional system for which one can design explicitly exact controls. We then justify the approximations which link up the complete and approximate systems. This yields approximate controllability results in the natural space

(L^{2}(\mathbb{R})^{2})

and also in stronger spaces corresponding to the domains of powers of the harmonic operator.

Résumé

Dans cet article, nous étudions les propriétés de contrôlabilité approchée pour un système d'équations de Schrödinger modélisant un ion piégé. Nous nous limitons à un contrôle d'une forme particulière, correspondant à des restrictions pratiques. Notre approche est fondée sur l'analyse de la contrôlablité d'un système approché de dimension finie, pour lequel il est possible de construire explicitement des contrôles exacts. Nous justifions alors précisément les approximations qui relient le système complet au système approché. Nous en déduisons des résultats de contrôlabilité approchée dans l'espace naturel

(L^{2}(\mathbb{R})^{2})

mais aussi dans des espaces plus forts correspondants aux domaines des puissances de l'opérateur harmonique.
Stillbirth and early neonatal mortality in rural Central Africa
Authors: Engmann Cyril , Matendo Richard , Kinoshita Rinko , Ditekemena John , Moore Janet , Goldenberg Robert L. , Tshefu Antoinette , Carlo Waldemar A. , McClure Elizabeth M. , Bose Carl , Wright Linda L. 
Published: February 2009

AbstractObjectiveTo develop a prospective perinatal registry that characterizes all deliveries, differentiates between stillbirths and early neonatal deaths (ENDs), and determines the ratio of fresh to macerated stillbirths in the northwest Democratic Republic of Congo.MethodBirth outcomes were obtained from 4 rural health districts.ResultsA total of 8230 women consented, END rate was 32 deaths per 1000 live births, and stillbirth rate was 33 deaths per 1000 deliveries. The majority (75%) of ENDs and stillbirths occurred in neonates weighing 1500 g or more. Odds of stillbirth and END increased in mothers who were single or who did not receive prenatal care, and among premature, low birth weight, or male infants. The ratio of fresh to macerated stillbirths was 4:1.ConclusionNeonates weighing 1500 g or more at birth represent a group with a high likelihood of survival in remote areas, making them potentially amenable to targeted intervention packages. The ratio of fresh to macerated stillbirths was approximately 10‐fold higher than expected, suggesting a more prominent role for improved intrapartum obstetric interventions.
Perspectives on risk management in supply chains
Authors: Narasimhan Ram , Talluri Srinivas 
Published: February 2009

AbstractManaging risk in supply chains is an important topic in supply chain management. The topic's importance is due to several industry trends currently in place: increase in strategic outsourcing by firms, globalizations of markets, increasing reliance on suppliers for specialized capabilities and innovation, reliance on supply networks for competitive advantage, and emergence of information technologies that make it possible to control and coordinate extended supply chains. This article identifies some important aspects of risk management in supply chains and summarizes the four articles that are in this special issue. This emerging area of research interest deserves considerable attention and it is our hope that the articles in this special issue would spur additional research on this important topic.