bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variational approach to the confined hydrogen atom with a moving nucleus
Authors: Fernández F. M. , Aquino N. , Flores‐Riveros A. 
Published: April 2011

AbstractWe calculate the ground‐state energy and other physical properties of the hydrogen atom inside a spherical box with an impenetrable wall. We apply the variational method and show that the total, kinetic, and potential energies for the moving nucleus model are greater than those for the case in which the nucleus is clamped at the box center. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
DFT study of the gas‐phase thermal decomposition kinetics of 2‐ethoxypyridine into 2‐pyridone
Authors: Marquez Edgar , Cordova Tania , Chuchani Gabriel 
Published: April 2011

AbstractThe mechanism of the gas‐phase elimination kinetics of 2‐ethoxypyridine has been studied through the electronic structure calculations using density functional methods: B3LYP/6‐31G(d,p), B3LYP/6‐31++G(d,p), B3PW91/6‐31G(d,p), B3PW91/6‐31++G(d,p), MPW1PW91/6‐31G(d,p), MPW1PW91/6‐31++G(d,p), PBEPBE/6‐31G(d,p), PBEPBE/6‐31++G(d,p), PBE1PBE1/6‐31G(d,p), and PBE1PBE1/6‐31++G(d,p). The elimination reaction of 2‐ethoxypyridine occurs through a six‐centered transition state geometry involving the pyridine nitrogen, the substituted carbon of the aromatic ring, the ethoxy oxygen, two carbons of the ethoxy group, and a hydrogen atom, which migrates from the ethoxy group to the nitrogen to give 2‐pyridone and ethylene. The reaction mechanism appears to occur with the participation of π‐electrons, similar to alkyl vinyl ether elimination reaction, with simultaneous ethylene formation and hydrogen migration to the pyridine nitrogen producing 2‐pyridone. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Conformational dependence of the electronic coupling in guanine–tryptophan complexes: A DFT study
Authors: Butchosa C. , Simon S. , Voityuk A. A. 
Published: April 2011

AbstractRadical cation states (electron holes) generated in DNA lead to mutagenic effects. In DNA–protein complexes, the holes can migrate from DNA to aromatic amino acid residues preventing the formation of the oxidative lesions. The efficiency of hole transfer (HT) may significantly depend on the arrangement of redox sites. This dependence is mainly determined by sensitivity of the electronic coupling of donor and acceptor to structural changes. Based on DFT calculations of a number of guanine–tryptophan (G–Trp) complexes, we explore the conformational dependence of HT electronic coupling in this dyad. Stacked and T‐shaped structures are considered. The electronic coupling in the system is shown to be responsive to the mutual arrangement of G and Trp. Although in most cases the probability of HT in T‐shaped conformations is predicted to be lower than in π stacks, several T‐type structures are found where HT should be very efficient. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem 112:1838–1843, 2012
Solvent effects on SN2 reaction between substituted benzyl chloride and chloride ion
Authors: Ebrahimi A. , Habibi Khorassani M. , Doosti M. 
Published: April 2011

AbstractThe effects of solvent on SN2 reaction between some substituted benzyl chlorides and chloride ion have been investigated by DFT and ab initio methods using the polarizabale continuum model. The activation energies are higher in the solution media relative to the gas phase and grow by the increase in the dielectric constant of solvent. The complexation energies in solution media are smaller than those in the gas phase and reduce with increasing the dielectric constant. The energy data are in good agreement with the geometrical parameters and substituent constants. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
An HMM approach for optimal investment of an insurer
Authors: Elliott Robert J. , Siu Tak Kuen 
Published: April 2011

SUMMARYIn this paper, we introduce a Hidden Markov Model (HMM) for studying an optimal investment problem of an insurer when model uncertainty is present. More specifically, the financial price and insurance risk processes are modulated by a continuous‐time, finite‐state, hidden Markov chain. The states of the chain represent different modes of the model. The HMM approach is viewed as a ‘dynamic’ version of the Bayesian approach to model uncertainty. The optimal investment problem is formulated as a stochastic optimal control problem with partial observations. The innovations approach in the filtering theory is then used to transform the problem into one with complete observations. New robust filters of the chain and estimates of key parameters are derived. We discuss the optimal investment problem using the Hamilton–Jacobi–Bellman (HJB) dynamic programming approach and derive a closed‐form solution in the case of an exponential utility and zero interest rate. Copyright © 2011 John Wiley & Sons, Ltd.
Asymptotic and robust stability of T‐S fuzzy genetic regulatory networks with time‐varying delays
Authors: Liu Jinliang , Yue Dong 
Published: April 2011

SUMMARYIn this paper, we propose and investigate a new general model of fuzzy genetic regulatory networks described by the Takagi–Sugeno (T‐S) fuzzy model with time‐varying delays. By using a Lyapunov functional approach and linear matrix inequality (LMI) techniques, the stability criteria for the delayed fuzzy genetic regulatory networks are expressed as a set of LMIs, which can be solved numerically by LMI toolbox in Matlab. Two fuzzy genetic network example are given to verify the effectiveness and applicability of the proposed approach. Copyright © 2011 John Wiley & Sons, Ltd.
Spatially adaptive semi‐supervised learning with Gaussian processes for hyperspectral data analysis
Authors: Jun Goo , Ghosh Joydeep 
Published: April 2011

AbstractThis paper presents a semi‐supervised learning algorithm called Gaussian process expectation‐maximization (GP‐EM), for classification of landcover based on hyperspectral data analysis. Model parameters for each land cover class are first estimated by a supervised algorithm using Gaussian process regressions to find spatially adaptive parameters, and the estimated parameters are then used to initialize a spatially adaptive mixture‐of‐Gaussians model. The mixture model is updated by expectation‐maximization iterations using the unlabeled data, and the spatially adaptive parameters for unlabeled instances are obtained by Gaussian process regressions with soft assignments. Spatially and temporally distant hyperspectral images taken from the Botswana area by the NASA EO‐1 satellite are used for experiments. Detailed empirical evaluations show that the proposed framework performs significantly better than all previously reported results by a wide variety of alternative approaches and algorithms on the same datasets. © 2011 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 4: 358–371, 2011
Activation of extracellular signal‐regulated kinase is critical for the discriminative stimulus effects induced by U‐50,488H
Authors: Yoshizawa Kazumi , Narita Minoru , Saeki Mai , Narita Michiko , Isotani Kana , Horiuchi Hiroshi , Imai Satoshi , Kuzumaki Naoko , Suzuki Tsutomu 
Published: April 2011

AbstractWe previously demonstrated that the discriminative stimulus effects of the κ‐opioid receptor agonist U‐50,488H were associated with its aversive effects in rats. However, its molecular signaling mechanisms are not fully understood. The aim of this study was to investigate the intracellular signaling that plays a role in mediating the discriminative stimulus effect induced by U‐50,488H. To better understand the involvement of molecular signaling mechanisms in the discriminative stimulus effects of U‐50,488H, rats were subjected to a drug discrimination paradigm, and levels of immunoreactivity and mRNA expression were determined in these rats. Although U‐50,488H‐trained rats did not show changes in the mRNA expression of typical dopamine (DA) receptors, NMDA receptor subunits, or transcriptional activators, there were remarkable changes in the levels of immunoreactivity of several phosphorylated protein kinases. The levels of immunoreactivity of phosphorylated p38 MAPK and phosphorylated calcium/calmodulin‐dependent protein kinase II (CaMKII) were significantly increased in the nucleus accumbens and amygdala in lever‐press, yoked and discrimination groups compared to a naive group. Furthermore, the level of phosphorylated cAMP response element‐binding protein was also increased in both the discrimination and yoked groups. In contrast, the immunoreactivity of phosphorylated extracellular signaling‐regulated kinase (ERK 1/2) was specifically increased in the discrimination group. These results suggest that the ERK signaling pathway in the nucleus accumbens and amygdala may be critical for the expression of the discriminative stimulus effects of U‐50,488H. Synapse, 2011. © 2011 Wiley‐Liss, Inc.
Apamin induces plastic changes in hippocampal neurons in senile Sprague–Dawley rats
Authors: Romero‐Curiel Alejandra , López‐Carpinteyro Diana , Gamboa Citlalli , De la cruz Fidel , Zamudio Sergio , Flores Gonzalo 
Published: April 2011

AbstractApamin is a neurotoxin extracted from honey bee venom and is a selective blocker of small‐conductance Ca2+‐activated K+ channels (SK). Several behavioral and electrophysiological studies indicate that SK‐blockade by apamin may enhance neuron excitability, synaptic plasticity, and long‐term potentiation in the CA1 hippocampal region, and, for that reason, apamin has been proposed as a therapeutic agent in Alzheimer's disease treatment. However, the dendritic morphological mechanisms implied in such enhancement are unknown. In the present work, Golgi–Cox stain protocol and Sholl analysis were used to study the effect of apamin on the dendritic morphology of pyramidal neurons from hippocampus and the prefrontal cortex as well as on the medium spiny neurons from the nucleus accumbens and granule cells from the dentate gyrus (DG) of the hippocampus. We found that only granule cells from the DG and pyramidal neurons from dorsal and ventral hippocampus were altered in senile rats injected with apamin. Our research suggests that apamin may increase the dendritic morphology in the hippocampus, which could be related to the neuronal excitability and synaptic plasticity enhancement induced by apamin. Synapse 2011. © 2011 Wiley‐Liss, Inc.
Lack of association between synapsin II (SYN2) gene polymorphism and susceptibility epilepsy: A case–control study and meta‐analysis
Authors: Haerian Batoul Sadat , Lim Kheng Seang , Tan Hui Jan , Wong Chee Piau , Wong Sau Wei , Tan Chong Tin , Raymond Azman Ali , Mohamed Zahurin 
Published: April 2011

AbstractObjective: The SYN2 rs3773364 A>G polymorphism has been proposed to be involved in susceptibility to epilepsy, but research results have been inconclusive. The aim of this study was to investigate the association between the SYN2 rs3773364 A>G polymorphism and susceptibility against epilepsy in a case–control study and a meta‐analysis. Methods: The SYN2 rs3773364 A>G polymorphism was successfully genotyped in 1182 samples (618 epilepsy patients) of Chinese, Indian, and Malay ethnicities. Meta‐analysis of the related studies, including this case–control study, was performed under alternative genetic models. Results: Data from the case–control study indicated no allelic and genotypic association of this locus with susceptibility to epilepsy in the tri‐ethnic Malaysian population. Similar finding was obtained by stratified analysis by epilepsy syndrome for idiopathic epilepsy. These results were verified by meta‐analysis of the related pooled data. Conclusions: Our study indicated that SYN2 rs3773364 A>G polymorphism is not a risk factor for susceptibility to epilepsy. Synapse 2011. © 2011 Wiley‐Liss, Inc.
Duration of persistent abnormal ductus venosus flow and its impact on perinatal outcome in fetal growth restriction
Authors: Turan O. M. , Turan S. , Berg C. , Gembruch U. , Nicolaides K. H. , Harman C. R. , Baschat A. A. 
Published: April 2011

AbstractObjectiveTo study if the duration of individual Doppler abnormalities is an independent predictor of adverse outcome in fetal growth restriction (FGR) caused by placental dysfunction.MethodsThis was a secondary analysis of patients with FGR (abdominal circumference < 5th percentile and umbilical artery (UA) pulsatility index (PI) elevation) who had at least three examinations before delivery. Days of duration of absent/reversed UA end‐diastolic velocity (UA‐AREDV), low middle cerebral artery PI (brain sparing), ductus venosus (DV) and umbilical vein Doppler abnormalities were related to stillbirth, major neonatal morbidity and intact survival.ResultsOne hundred and seventy‐seven study participants underwent a total of 1069 examinations. The duration of an absent/reversed a‐wave in the DV (DV‐RAV) was significantly higher in stillbirths (median, 6 days) compared with intact survivors and those with major morbidity (median, 0 days for both; P = 0.006 and P = 0.001, respectively). Duration of brain sparing was also longer in stillbirth cases compared with intact survivors (median, 19 days vs. 9 days, P = 0.02). Stepwise multinomial logistic regression showed that gestational age at delivery was a significant codeterminant of outcome for all arterial Doppler abnormalities when the DV a‐wave was antegrade. However, when present, the duration of DV‐RAV was the only contributor to stillbirth (probability of stillbirth = 1/(1 + exp − (interval to delivery × 1.03 − 2.28)), r2 = 0.73). Receiver–operating characteristics curve statistics showed that a DV‐RAV for > 7 days predicted stillbirth (100% sensitivity, 80% specificity, likelihood ratio = 5.0, P < 0.0001). In contrast, neither neonatal death nor neonatal morbidity was predicted by the days of persistent DV‐RAV.ConclusionsThe duration of absent or reversed flow during atrial systole in the DV is a strong predictor of stillbirth that is independent of gestational age. While prematurity remains the strongest predictor of neonatal risks it is unlikely that pregnancy can be prolonged by more than 1 week in this setting. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
A framework to determine optimal offshore grid structures for wind power integration and power exchange
Authors: Trötscher Thomas , Korpås Magnus 
Published: April 2011

ABSTRACTThis paper presents a framework to find optimal offshore grid expansions using a transportation model of the power grid. The method extends the standard mixed‐integer linear programming approach to the solution of the transmission expansion planning problem to account for fluctuations in wind power generation and load; this makes the method especially suited to identify optimal transnational offshore high‐voltage direct current grid structures for the integration of large amounts of offshore wind power. The applicability of the method is demonstrated by a case study of the North Sea region. Copyright © 2011 John Wiley & Sons, Ltd.
A method for defining wind turbine setback standards
Authors: Rogers Jonathan , Slegers Nathan , Costello Mark 
Published: April 2011

ABSTRACTSetback distances established by regulatory authorities to minimize the probability of blade fragment impact with roads, structures and infrastructure can often have a significant impact on wind farm development. However, these minimum distance requirements typically rely on arbitrary rules of thumb and are not based on a physical or probabilistic analysis of blade throw. The work reported here uses a probabilistic approach to evaluate the effectiveness of current standards and to propose a new technique for determining setback distances. This is accomplished through the use of a dynamic model of wind turbine blade failure coupled with Monte Carlo simulation techniques applied to three different wind turbines. It is first shown that common setback standards based on turbine height and blade radius provide inconsistent and inadequate protection against blade throw. Then, using a simplified dynamic analysis of a thrown blade fragment, it is shown that the release velocity of the blade fragment is the critical factor in determining the maximum distance fragments are likely to travel. The importance of release velocity is further verified through simulation results. Finally, a new method for developing setback standards is proposed based on an acceptable level of risk. Given specific wind turbine operational parameters and a set of failure probabilities, the new method leverages realistic blade throw modeling to produce setback standards with a valid physical foundation. Copyright © 2011 John Wiley & Sons, Ltd.
Machine learning
Authors: Alpaydın Ethem 
Published: April 2011

AbstractMachine learning is already a mature field with significant theoretical work and an impressive suite of applications. I will discuss learning algorithms together with some example applications, as well as the current challenges and research areas. WIREs Comp Stat 2011 3 195–203 DOI: 10.1002/wics.166This article is categorized under:

Software for Computational Statistics > Artificial Intelligence and Expert Systems
Statistical Learning and Exploratory Methods of the Data Sciences > Pattern Recognition
Statistical Learning and Exploratory Methods of the Data Sciences > Knowledge Discovery
Statistical Learning and Exploratory Methods of the Data Sciences > Clustering and Classification
Information enhancement for data mining
Authors: Zhang Shichao 
Published: April 2011

AbstractInformation enhancement techniques are desired in many areas such as data mining, machine learning, business intelligence, and web data analysis. Information enhancement mainly includes the following topics: data cleaning, data preparation and transformation, missing values imputation, feature and instance selection, feature construction, treatment of noisy and inconsistent data, data integration, data collection and housing, information enhancement, web data availability, web data capture and representation, and the others. It is impossible to outline all the research topics in a single paper. In this study, we discuss the information enhancement for data mining with existing missing data imputation techniques. We first review the current research on imputing missing values, and then experimentally evaluate the techniques and demonstrate the efficiency of missing data imputation techniques to enhance information in the process of pattern discovery from datasets with missing values. © 2011 John Wiley & Sons, Inc. WIREs Data Mining Knowl Discov 2011 1 284–295 DOI: 10.1002/widm.21This article is categorized under:

Fundamental Concepts of Data and Knowledge > Data Concepts
Gene expression modular analysis: an overview from the data mining perspective
Authors: Pascual‐Montano Alberto 
Published: April 2011

AbstractIn this review, we discuss the main problems and state‐of‐the‐art solutions applied to the field of gene expression. Specific data analysis workflows have been developed in parallel with the technology and currently cover a very wide spectrum of methods and applications needed to give answers to a lot of scientific questions that this type of data are producing. Computer science and, more specifically, the data mining area is still benefiting from a large set of real‐case scenarios to apply and develop new ideas and tools for discovering biological knowledge and new information from this experimental data. In this article, we make the reader aware of the main problems that still persist and provide a description of the methodologies that are applied for classification, clustering, and functional exploration of gene expression data. © 2011 John Wiley & Sons, Inc.WIREs Data Mining Knowl Discov2011 1 381–396 DOI: 10.1002/widm.29This article is categorized under:Algorithmic Development > Biological Data MiningApplication Areas > Science and TechnologyTechnologies > Classification
Synthesis and Structure of Tetrameric Germa‐closo‐dodecaborate Silver Halides
Authors: Dimmer Jörg‐Alexander , Wesemann Lars 
Published: April 2011

AbstractThe reaction of germa‐closo‐dodecaborate with oneequivalent of silver halide AgX (X = Cl, Br) leads to the tetrameric1:1 adducts [Et3MeN]8[{AgCl(GeB11H11)}4] (1) and [Et3MeN]8[{AgBr(GeB11H11)}4] (2). A cubane‐like structure was determined in the solid state by single‐crystal X‐ray diffraction. The compounds were characterized by crystal structure analysis, 11B NMR spectroscopy and elemental analysis.
Darstellung und Reaktionen von Selenocarbonyldifluorid und seines cyclischen Dimeren 2,2,4,4‐Tetrafluor‐1,3‐diselenetan [l]
Authors: Haas A. , Koch B. , Welcman N. 
Published: April 2011

AbstractInhaltsübersicht. Das erstmals hergestellte B(SeCF3)3 zerfällt unter dem katalytischen Einfluß von Alkalifluoriden zu F2C=Se und BF3. In Anwesenheit von BF3 polymerisiert F2CSe bereits. bei −;80°C. Oberhalb 150°C depolymerisiert (F2CSe)n wieder zu F2C=Se und. Durch Halogenaddition an F2C = Se gewinnt man F2XCSeX (X = Cl, Br). Das in der Reihe Cl3–nFnCSeCl noch fehlende Cl2FCSeCl wird durch Umsetzung von CSe2, ClF und Cl2 synthetisiert. FnCl3–nCSeCl (n = 1. 2) liefert mit Zinn die entsprechenden symmetrischen Diselane, mit AgCN die Selenocyanate. Durch Halogenaustausch mit BX3 (X = Cl, Br) wirdumgewandelt. XC(S)Cl reagiert mit Hg(SeCF3)2 zu CF3SeC(S)X (X = F, Cl. CF3Se). Daraus werden durch Chloraddition die entsprechenden Sulfenylchloride synthetisiert. IR‐NMR‐ und Massenspektren der neu hergestellten Substanzen werden angegeben.Preparation and Reactions of SeCF2 and its Cyclic Dimer 2,2,4,4‐Tetrafluoro‐1,3‐diselenetaneAbstract. B(SeCF3)3, prepared for the first time, decomposes under the influence of alkali metal fluorides to F2C=Se and BF3. In presence of BF3, SeCF2 polymerizes even at −80°C. Above 150°C (F2CSe)n depolymerizes to F2C = Se andHalogen addition to F2C=Se produces F2XCSeX (X = Cl, Br). The compound Cl2FCSeCl could be synthesized by the reaction of CSe2 with ClF and Cl2. These selenenylchlorides react with tin producing the corresponding symmetric diselenides whereas with AgCN the selenocyanates are formed.can be transformed tothrough halogen exchange reaction with BX3 (X = Cl, Br). XC(S)Cl reacts with Hg(SeCF3)2 to give CF3SeC(S)X (X = F, Cl. CF3Se), from which the corresponding sulfenylchlorides can be synthesized by chlorine addition. I.r., n.m.r., and mass spectra of the newly prepared compounds are reported.
Über Sulfide der vierten Hauptgruppe vom Typ AIIBIVS3 und die Kristallstruktur des SnGeS31)
Authors: Fenner J. , Mootz R. D. 
Published: April 2011

AbstractInhaltsübersicht. Die Elemente der vierten Hauptgruppe bilden vier Sulfide vom Typ AIIBIVS3: SnGeS3, PbGeS3, SnSnS3, PbSnS3. Die Verbindungen lassen sich durch Reaktion der Elemente sowie der binären Sulfide darstellen. Es können gute Einkristalle erhalten werden. Auf Grund chemischer, physikalischer und struktureller Eigenschaften lassen sich die Sulfide in zwei Gruppen einteilen. Bestimmend hierfür ist das Element in der Oxydationsstufe +IV. Die Struktur der isotypen Verbindungen SnGeS3 und PbGeS3 wurde durch eine vollständige Röntgenstrukturanalyse des SnGeS3 bestimmt. Cherakteristisch für die Struktur sind Ketten aus eckenverknüpften GeS4‐Tetraedern, die über Sn‐Atome zu stark gewellten Schichten vernetzt sind.Type AIIBIVS3 Sulfides of the Fourth Main Group and the Crystal Structure of SnGeS3Abstract. The group IV elements form sulfides of the type AIIBIVS3: SnGeS3, PbGeS3, SnSnS3, PbSnS3. The compounds are formed through the reaction of the elements and of the binary sulfides. Good single crystals are obtained. The sulfides can be sorted into two groups due to their physical, chemical and structural properties. The element in the oxidation state +IV determines these properties. The structure of the isotypic compounds SnGeS3 and PbGeS3 was determined by a complete x‐ray structure analysis of SnGeS3. Characteristic for the structure are chains of GeS4 tetrahedra sharing to vertices each. The chains are linked into corrugated layers by the Sn atoms.