bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Theoretical Study on the Low‐Lying Excited States of 2,2′:5′,2′′‐Terthiophene and 2,2′:5′,2′′:5′′,2′′′‐Quaterthiophene
Authors: Rubio Mercedes , Merchán Manuela , Ortí Enrique 
Published: June 2005

AbstractThe nature and properties of the low‐lying singlet and triplet valence excited states of 2,2′:5′,2′′‐terthiophene (terthiophene) and 2,2′:5′,2′′:5′′,2′′′‐quaterthiophene (tetrathiophene) are discussed on the basis of high‐level ab initio computations. The spectroscopic features determined experimentally for short α‐oligothiophenes are rationalised on theoretical grounds. Special attention is devoted to the nonradiative decay process through intersystem crossing (ISC) from the singlet to the triplet manifold, which is known to be relatively less efficient in tetrathiophene. Along the geometry relaxation of the S1 state of terthiophene, the S1 and T2 states become degenerate, which leads to a favourable situation for the occurrence of ISC. The parallel process is expected to be less favoured in tetrathiophene because of the less efficient spin–orbit coupling and the increase of the S1–T2 energy gap.
Molecular Dynamics and Conformational Kinetics of Mono‐ and Disaccharides in Aqueous Solution
Authors: Behrends Ralph , Kaatze Udo 
Published: June 2005

AbstractAcoustical attenuation spectra between 10 kHz and 2 GHz, complex dielectric spectra between 300 kHz and 40 GHz, and time‐resolved non‐equilibrium measurements are reported for aqueous solutions of various mono‐ and disaccharides with and without 2:1 valent salts. The spectra reveal a variety of relaxation regimes with relaxation times between 1 μs and 10 ps. In addition, the time‐resolved observations enable the study of the mutarotation with relaxation times on the order of 103 s. Variation of the concentration and temperature as well as a careful choice of the saccharides allow a discussion of the relaxation processes in terms of a chair–chair ring inversion, two modes of pseudorotation, an exocyclic hydroxymethyl group rotation, a carbohydrate–carbohydrate association, and, in the disaccharide solutions, a rotation of the rings relative to another. Salt‐containing solutions show also relaxation phenomena reflecting different steps cation–carbohydrate association and variations in the carbohydrate conformational isomerizations and associations due to interactions with cations.
Theoretical and Experimental Study of the Adsorption of Neutral Glycine on Silica from the Gas Phase
Authors: Lomenech C. , Bery G. , Costa D. , Stievano L. , Lambert J. F. 
Published: June 2005

AbstractThe adsorption of neutral glycine onto amorphous silica was investigated both theoretically and experimentally. DFT calculations were performed at the BLYP‐631++G** level using a cluster approach. Several possible configurations involving the formation of H bonds between glycine and one, two, or three silanol groups (SiOH) were considered. The most favorable bonding of glycine with one silanol group (45 kJ mol−1) occurs through the COOH moiety, thus forming a cycle in which the CO group is an H‐bond acceptor whereas the acidic OH group is an H‐bond donor. With two or three silanol groups, additional H bonds are formed between the amine moiety and the silanol groups, which leads to an increased adsorption energy (70 and 80 kJ mol−1 for two and three silanol groups, respectively). Calculated νCO, δHNH, and δHCH values are sensitive to the adsorption mode. A bathochromic shift of νCO as compared to the νCO of free glycine (calculated in the 1755–1790 cm−1 range) is found for glycine in interaction with silanol(s). The more H bonds are formed between the COOH moiety and silanol groups, the higher the bathochromic shift. For δHNH, no shift is found for glycine adsorbed on one and two silanol groups (where the amine is either not bound or an H‐bond donor), whereas a bathochromic shift is calculated with three silanols when the amine moiety is an H‐bond acceptor. Experimental FTIR spectra performed at room temperature for glycine adsorbed at 160 °C on Aerosil amorphous silica exhibit bands at 1371, 1423, 1630, and 1699 cm−1. The experimental/calculated frequencies have their best correspondence for glycine adsorbed on two silanol groups. It is important to note that the forms giving the best correspondence to experimental frequencies are the most stable ones.
The Excited‐State Chemistry of Phycocyanobilin: A Semiempirical Study
Authors: Göller Andreas H. , Strehlow Dietmar , Hermann Gudrun 
Published: June 2005

AbstractBased on previous time‐resolved absorption studies, phycocyanobilin undergoes a photoreaction from an A‐ into a B‐ and C‐form, with the latter two photoproducts showing absorption spectra red‐shifted from A. To identify the molecular mechanism involved in the excited‐state reactions, the structural origin of the red shift in the absorption spectra is investigated. Using semiempirical AM1 calculations that include configuration interaction by pair doubles excitation configuration interaction, the absorption spectra of different conformers as well as different protonation states were calculated. The results clearly indicate a pronounced red shift in the spectra of structures either protonated or deprotonated at the basic/acidic centres of the tetrapyrrole chromophore whereas, in contrast, conformational changes alone result in a blue shift. Furthermore, it is shown by quantum chemical calculations that the basicity of phycocyanobilin is much higher in the excited than in the ground state, with a decrease in the excited‐state pKB* of ≈9.5 units. The acidity is only slightly enhanced with a drop in pKA* of only ≈1.6 units. From these findings, a reaction model for the excited‐state processes in phycocyanobilin is proposed. According to this model, photoexcitation of phycocyanobilin triggers an excited‐state proton transfer giving rise to the formation of a protonated species. In parallel, the local increase in the medium pH associated with protonation then forwards a deprotonation at an acidic NH‐group so that in effect both protonated and deprotonated phycocyanobilin would arise from the initial photoreaction and account for the observed red shift in the spectra of the B‐ and C‐forms.
Cooperativity and Proton Transfer in Hydrogen‐Bonded Triads
Authors: Mó Otilia , Yáñez Manuel , Del Bene Janet E. , Alkorta Ibon , Elguero José 
Published: June 2005

AbstractAb initio MP2/6‐311+G(3df,2pd) and MP2/aug‐cc‐pVTZ calculations have been carried out to investigate the structures and properties of AH⋅XH⋅YH3(A=F, Cl; X=F, Cl; Y=N, P) hydrogen‐bonded complexes. Significant cooperative effects are observed in the XH⋅YH3dyads in the triads due to the presence of the polar near‐neighbor AH. These effects are greater when the polar partner is HF, which is a better proton donor than HCl. Structural changes, red shifts of proton‐donor stretching frequencies, nonadditive interaction energies, and electron density redistributions unambiguously demonstrate that the XH⋅⋅⋅Y hydrogen bond (HB) is stronger in the triads than in the corresponding dyads, while the XH bond of the proton donor becomes weaker. Even more pronounced cooperative effects are observed in the AH⋅XH dyads due to the presence of the YH3partner. These effects are weaker in complexes having PH3rather than NH3as the proton acceptor, since NH3is a stronger base. Cooperativity also enhances the proton‐donating ability of the YH3moiety, with the result that all complexes except FH⋅FH⋅PH3are cyclic. Cooperativity, together with the ease of breaking the ClH bond in ClH⋅ClH⋅NH3and FH⋅ClH⋅NH3, leads to proton transfer (PT), so that these two complexes are better described as approaching hydrogen‐bonded ClHCl−⋅+HNH3and FHCl−⋅+HNH3ion pairs.
Synthesis and Optical Properties of Silver Nanoparticles and Arrays
Authors: Evanoff David D. , Chumanov George 
Published: June 2005

AbstractThis Minireview systematically examines optical properties of silver nanoparticles as a function of size. Extinction, scattering, and absorption cross‐sections and distance dependence of the local electromagnetic field, as well as the quadrupolar coupling of 2D assemblies of such particles are experimentally measured for a wide range of particle sizes. Such measurements were possible because of the development of a novel synthetic method for the size‐controlled synthesis of chemically clean, highly crystalline silver nanoparticles of narrow size distribution. The method and its unique advantages are compared to other methods for synthesis of metal nanoparticles. Synthesis and properties of nanocomposite materials using these and other nanoparticles are also described. Important highlights in the history of the field of metal nanoparticles as well as an examination of the basic principles of plasmon resonances are included.
Clinical evaluation of an aerolysin‐based screening test for paroxysmal nocturnal haemoglobinuria
Authors: Peghini Pietro Edmondo , Fehr Jörg 
Published: June 2005

AbstractBackgroundRecently, a toxin produced by Aeromonas hydrophila was demonstrated to bind directly to the glycosyl‐phosphatidyl‐inositol (GPI) anchor. After coupling it to a fluorescent dye and applying it in fluorescence‐activated cell scanning (FACS), this property was exploited to detect GPI‐negative cells in the diagnosis of paroxysmal nocturnal haemoglobinuria (PNH).MethodsWe used this reagent according to a very simple staining protocol followed by single‐colour FACS and compared the results in patients with PNH and normal controls with those obtained with antibody‐mediated detection of cells lacking GPI‐anchored proteins.ResultsWe observed very good concordance between the two methods, with correlation coefficients (R2) of quantified GPI‐deficient cell populations ranging from 0.952 to 0.969. The lower limit of detection was determined at 0.50% GPI‐negative cells, which was in the range obtained with double‐colour staining with antibodies (0.20–1.00%, depending on the antibody). A significant correlation was observed between the fraction of GPI‐negative granulocytes and laboratory parameters of haemolysis, with the erythrocyte creatine having the best correlation (R2 = 0.671, P < 0.0001).ConclusionsUsing this protocol, we were able to reliably diagnose PNH with a high sensitivity. The test allows the identification of GPI‐negative granulocyte populations as small as 0.5%. © 2005 Wiley‐Liss, Inc.
Effect of cytological fixative and environmental conditions on nuclear morphometric characteristics of squamous epithelial cells in sputum
Authors: Gottschall E. Brigitte , McGinley John N. , Spoelstra Nicole , Knott Katrina , Wolfe Pamela , Rose Cecile , Singh Meenakshi , Thompson Henry J. 
Published: June 2005

AbstractBackgroundSputum samples for lung cancer screening trials are typically collected at home into specimen containers prefilled with cytologic fixative. Collection, transit, and storage expose samples to environmental conditions that may introduce artifacts that could confound evaluation. We examined whether the type of cytological fixative and exposure to different environmental conditions introduces artifacts that affect cytological analysis.MethodsSputum fixed in Saccomanno fluid (SAC), containing methyl, ethyl, and propyl alcohols and polyethylene glycol, or CytoRich Red solution (CRR), containing methyl and isopropyl alcohols and ethylene glycol, plus formaldehyde, was aliquoted and exposed for 8 h to the following conditions: (a) −20°C freezer, (b) 60°C oven, (3) direct sunlight, and (4) room temperature. Cell morphometry was evaluated using computer‐assisted image analysis (CAIA).ResultsThe values obtained for CAIA analysis of sputum were affected by the type of fixative used. Temperature extremes and sunlight dramatically altered nuclear morphometry of SAC‐fixed cells. Artifacts were not observed in CRR‐fixed cells.ConclusionsThe effects of environmental exposures were minimized if sputum was placed in a formalin‐containing fixative such as CRR. If an alcohol‐based fixative such as SAC is used, sample handling, transport, and storage must be monitored to prevent the introduction of artifacts. © 2005 Wiley‐Liss, Inc.
Generalization of circuit simulator by automatic differentiation
Authors: Kato Toshiji 
Published: June 2005

AbstractCircuit simulators have often been used for power electronic system design. However, most of them are limited in their application class to one with fixed elements because they can only handle programmed or fixed element characteristics. To overcome this disadvantage, a simulator should be flexible enough to handle any combination of characteristics of available mathematical functions and operations. It is a problem how to compute Jacobian elements or partial derivatives with respect to circuit variables. This paper proposes a way to compute the derivatives by using the automatic differentiation method which is simple and accurate. The principle and application examples are described. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 47–54, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20075
Electroencephalogram‐based control of a mobile robot
Authors: Tanaka Kazuo , Matsunaga Kazuyuki , Hori Shigeki 
Published: June 2005

AbstractThis paper presents electroencephalogram‐based control of a mobile robot. The purpose of control is to achieve direction control of a mobile robot only by electroencephalogram. We develop an algorithm for directing direction thinking (“going left” or “going right”) and apply it to direction control of a mobile robot. The algorithm is based on time–frequency domain analysis using continuous wavelet transformation. Our experimental results demonstrate the possibility of achieving direction control of a mobile robot only by electroencephalogram. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 39–46, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20109
Application of Tabu‐BOA to acquire multimodal and multiobjective solutions for electric equipment configuration problems in a power plant
Authors: Katsumata Yuji , Terano Takao 
Published: June 2005

AbstractThis paper applies the Bayesian Optimization Algorithm with Tabu Search (Tabu‐BOA) to electric equipment configuration problems in a power plant. Tabu‐BOA is a hybrid evolutionary computation algorithm with competent genetic algorithms and meta‐heuristics. The configuration problems we consider have complex combinatorial properties, and therefore are hard to formulate and solve via conventional mathematical programming techniques. Using the proposed method, we have solved the following problems (in order of increasing complexity): (1) cost minimization of electric equipment configuration and the corresponding cabling, (2) plus choice of the power plant operation patterns, (3) plus parallel operation of multiple transformers, (4) plus change of the supply voltages (high voltage or low voltage) to the electric power load, and (5) with addition of another objective, that is, both minimization of the cost and maximization of the surplus power supply. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 8–20, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20150
Optimization of the simultaneous removal of nitrogen and organic matter from fishery wastewaters
Authors: Aspé Estrella , Martí M. Cristina , Roeckel Marlene 
Published: June 2005

AbstractAnaerobic treatment of saline and protein‐rich effluents reduces the organic concentration but forms ammonium that hinders nitrogen removal in a later aerobic treatment. The goal of this work was to optimize the design of a denitrifying–nitrifying system for the simultaneous removal of organic matter and nitrogenous compounds from fishery effluents to meet the Chilean legal standards and to compare pre‐ and postdenitrification processes in the biological treatment of high‐strength effluents to minimize the total volume of biological reactors required. A predenitrifying system, that included three reactors—acidifying anaerobic filter, denitrifying (anoxic) filter, and aerobic‐active sludge (nitrifying reactor) with recycle to the denitrifying reactor—reduced nitrogen to 0.33 g of total ammonia nitrogen (TAN) L−1, well above the allowed 0.05 g total nitrogen L−1. The predenitrifying system with a second denitrifying reactor, to which organic matter was added, met the legal organic matter and nitrogen emission concentrations (0.042 g TAN L−1). Conversions were 99.0, 92.5, 90.9, and 99.0% for the anaerobic digestion, first denitrification, nitrification, and second denitrification, respectively. © 2005 American Institute of Chemical Engineers Environ Prog, 2005
Assessment of non‐Fickian subgrid‐scale models for passive scalar in a channel flow
Authors: Montreuil E. , Labbé O. , Sagaut P. 
Published: June 2005

AbstractIn order to assess new subgrid‐scale (SGS) models for a passive scalar, several large eddy simulations of a turbulent channel flow with passive scalar, for various Prandtl numbers ranging from 0.1 to 2.0 are carried out. These models are not based on the classical Fickian approximation and do not necessarily induce an alignment between the SGS heat flux vector and the gradient of the resolved temperature. Five SGS models are investigated on two grids. To validate the simulations, statistical quantities such as mean temperature, temperature variance and turbulent heat flux are compared with available data obtained by direct numerical simulation (DNS). The SGS dissipation is computed for different models in order to analyse its behaviour. The turbulence structures based on instantaneous velocity and temperature are described to study the correlations between these two fields. Among the assessed models, those consisting in Fickian and non‐Fickian parts seem to be full of promise. Copyright © 2005 John Wiley & Sons, Ltd.
Option pricing with a non‐zero lower bound on stock price
Authors: Dong Ming 
Published: June 2005

AbstractBlack, F. and Scholes, M. (1973) assume a geometric Brownian motion for stock prices and therefore a normal distribution for stock returns. In this article a simple alternative model to Black and Scholes (1973) is presented by assuming a non‐zero lower bound on stock prices. The proposed stock price dynamics simultaneously accommodate skewness and excess kurtosis in stock returns. The feasibility of the proposed model is assessed by simulation and maximum likelihood estimation of the return probability density. The proposed model is easily applicable to existing option pricing models and may provide improved precision in option pricing. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:775–794, 2005
Survival of commodity trading advisors: 1990–2003
Authors: Gregoriou Greg N. , Hübner Georges , Papageorgiou Nicolas , Rouah Fabrice 
Published: June 2005

AbstractThis article investigates the mortality of Commodity Trading Advisors (CTAs) over the 1990–2003 period, a longer horizon than any encompassed in the literature. A detailed survival analysis over the full range of CTA classifications is provided, and it is found that the median lifetime of CTAs in this sample is different than previously documented. Through the implementation of nonparametric, parametric, and semiparametric statistical techniques, it is emphasized that CTA survivorship is heavily contingent on the strategy followed by the fund. Furthermore, a significant positive size effect on survival is shown, whereas poor returns, and to a lesser extent, high‐risk exposure, appear to hasten mortality. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:795–815, 2005
Is investor misreaction economically significant? Evidence from short‐ and long‐term S&P 500 index options
Authors: Cao Charles , Li Haitao , Yu Fan 
Published: June 2005

AbstractSeveral recent studies present evidence of investor misreaction in the options market. Although the interpretation of their results is still controversial, the important question of economic significance has not been fully addressed. Here this gap is addressed by formulating regression‐based tests to identify misreaction and its duration and constructing trading strategies to exploit the empirical patterns of misreaction. Regular S&P 500 index options and long‐dated S&P 500 LEAPS are used to find an underreaction that on average dissipates over the course of 3 trading days and an increasing misreaction that peaks after four consecutive daily variance shocks of the same sign. Option trading strategies based on these findings produce economically significant abnormal returns in the range of 1–3% per day. However, they are not profitable in the presence of transaction costs. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:717–752, 2005
Chromosome 22 tiling‐path array–CGH analysis identifies germ‐line‐ and tumor‐specific aberrations in patients with glioblastoma multiforme
Authors: de Ståhl Teresita Díaz , Hartmann Christian , de Bustos Cecilia , Piotrowski Arkadiusz , Benetkiewicz Magdalena , Mantripragada Kiran K. , Tykwinski Tomasz , von Deimling Andreas , Dumanski Jan P. 
Published: June 2005

AbstractGliomas are common and frequently malignant tumors of the central nervous system. Recurrent allelic losses of chromosome 22 have been reported in gliomas, indicating tumor‐suppressor genes at this location. However, the target genes are still unknown. We applied a high resolution tiling‐path chromosome 22 array to a series of 50 glioblastoma samples, with the aim of investigating the underlying abnormalities in both constitutional and tumor‐derived DNA. We detected hemizygous deletions in 28% of the tumors (14 of 50), with monosomy 22 (10 of 50) being the predominant pattern. The distribution of overlapping hemizygous deletions delineated two putative tumor‐suppressor loci (11.1 and 3.08 Mb in size) across 22q. Most strikingly, we identified two distinct loci affected by regional gains. Both alterations were of germ‐line origin and were unique to samples from patients affected with tumors. Analysis of these two amplified regions revealed the presence of two interesting candidate genes: TOP3B and TAFA5. The TOP3B gene encodes a protein that seems to function in the unlinking of parental strands at the final stage of DNA replication and/or in the dissociation of structures in mitotic cells that could lead to recombination. The TAFA5 gene belongs to a novel family of proteins with similarity to chemokines and brain‐specific expression. The role of the identified candidate loci should be studied further. Our results demonstrated the power of array‐CGH to determine DNA copy number alterations in the context of germ‐line‐ and tumor‐specific aberrations. © 2005 Wiley‐Liss, Inc.