bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential expression of 17β‐hydroxysteroid dehydrogenase isozyme genes in prostate cancer and noncancer tissues
Authors: Koh Eitetsu , Noda Toru , Kanaya Jiro , Namiki Mikio 
Published: October 2002

AbstractBACKGROUNDThe adrenal steroids dehydroepiandrosterone and androstenediones are converted into active androgen testosterone in prostatic tissues. Different 17β‐hydroxysteroid dehydrogenase (17βHSD) isozymes are characterized by either oxidation or reduction reactions. These redox reactions represent an important step in both biosynthesis and metabolism of androgens. This study presents the differential expression of 17βHSD isozyme genes in cancerous and noncancerous prostate tissues of in vivo samples.METHODSThirty‐four fresh specimens of transrectal prostatic needle biopsy were obtained; 11 were pathologically diagnosed as adenocarcinoma and 23 as without malignancy. The gene expression levels of five isozymes (type 1–5) of 17βHSD were evaluated. The quantification of gene expression was assessed by means of the real‐time polymerase chain reaction.RESULTSThe expression levels of the type 3 17βHSD gene with malignancy were significantly higher than those in prostatic tissues without malignancy, and those of type 2 17βHSD with malignancy were significantly lower than those in nonmalignant tissues. There were no significant differences in 17βHSD type 1, type 4, and type 5 gene expression in cancerous and noncancerous tissues.CONCLUSIONOur results suggest that 17βHSD type 2 and type 3 play an important role in the conversion of adrenal steroids into potential androgens in prostate cancer tissue. Prostate 53: 154–159, 2002. © 2002 Wiley‐Liss, Inc.
Searching for quantitative entropy‐enthalpy compensation among protein variants
Authors: Beasley James R. , Doyle Donald F. , Chen Lixin , Cohen David S. , Fine Bryan R. , Pielak Gary J. 
Published: October 2002

AbstractEntropy‐enthalpy (SH) compensation occurs when a small change in ΔG is caused by large, and nearly compensatory, changes in ΔH and ΔS. It is considered a ubiquitous property of reactions in water. Because water is intimately involved in protein stability, SH compensation among protein variants, if it exists, could lead to important knowledge about protein‐water interactions. In light of recent theoretical work on SH compensation, we gathered thermodynamic data for >200 protein variants to seek evidence for the simplest quantitative model of SH compensation (i.e., The van't Hoff denaturation enthalpy divided by the van't Hoff denaturation entropy is a constant). We conclude that either the data are insufficient to support the idea that quantitative SH compensation is a general feature of variant proteins or that such compensation does not exist. This study reinforces the idea that ΔH‐versus‐ΔS plots should not be used to provide evidence for SH compensation. Proteins 2002;49:398–402. © 2002 Wiley‐Liss, Inc.
Molecular diagnostic procedures for production of pathogen‐free propagation material
Authors: Manulis Shulamit , Chalupowicz Laura , Dror Orit , Kleitman Frida 
Published: October 2002

AbstractProduction of disease‐free propagation material is a major means of controlling most bacterial diseases of plants, particularly when neither resistant clones nor effective chemical treatments are available. For this purpose sensitive, specific and rapid detection methods are required. The advent of molecular biology and, in particular, the polymerase chain reaction (PCR) has opened new ways for the characterization and identification of plant pathogens and the development of disease‐management strategies. PCR‐based detection methods rely on the development of primers for the specific detection of the pathogen. The use of pathogenicity genes as targets for primer design is the preferred procedure for obtaining specific primers but other procedures may also be useful for this purpose. In the present review we describe four examples of procedures for detecting four important bacterial pathogens in Israel: Erwinia herbicola pv gypsophilae in gypsophila, Xanthomonas campestris pv pelargonii in geranium, Agrobacterium tumefaciens in asters and roses, and Xanthomonas campestris pv campestris in crucifers. Procedures for constructing specific PCR primers for each bacterium are illustrated and discussed as well as the combination of PCR with other methods.© 2002 Society of Chemical Industry
An over‐current protection module for telephone network line cards—an analysis of electro‐thermal properties
Authors: Zarnik Marina Santo 
Published: October 2002

AbstractIn this paper the results of a finite‐element analysis of the electro‐thermal behaviour of an over‐current protection thick‐film hybrid module are presented. The module was designed for protecting the line card of a telephone network against an abnormal surge of current, resulting from accidental shorts between adjacent power feed lines. The switching time of the device is crucial to its effectiveness as a protective element. A transient finite‐element thermal analysis was performed in order to predict the dynamic temperature states at the critical points of the circuit design and to evaluate the influence on the switching characteristics. A comparison between simulated and practical results is given. Copyright © 2002 John Wiley & Sons, Ltd.
A theory of excitation–energy transfer regarded as nonadiabatic transition and its comparison to Förster's theory
Authors: Okuno Yoshishige , Mashiko Shinro 
Published: October 2002

AbstractWe propose a rate‐constant expression for an excitation–energy transfer between two molecules that is regarded as a nonadiabatic transition between two adiabatic electronic states. It is shown that under weak intermolecular interaction the approximately derived rate constant increases with the increase in pseudo‐Coulombic interaction \documentclass{article}\pagestyle{empty}\begin{document}$\langle \phi_{e}^{A}\phi_{g}^{B}|H|\phi_{g}^{A}\phi_{e}^{B}\rangle_{\mathbf{r}}$\end{document} and depends on the differences in the potential energies and the potential derivatives of the initial and final electronic states. In addition, the rate constant under strong interaction is shown to decrease with increasing pseudo‐Coulombic interaction. We show that our expression has the advantage that it can be applied to the excitation–energy transfer under the (not very) weak and the strong coupling limits which cannot be addressed by Förster's theory. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Theoretical analysis of cyclic reaction mechanisms of two ethylenes
Authors: Sakai Shogo 
Published: October 2002

AbstractThe reaction mechanisms of cyclic addition of two ethylenes were investigated by ab initio molecular orbital methods. The treated pathways were two supra‐supra [2s + 2s] with D2h or C2v symmetries and one supra‐antara [2s + 2a] with C2 symmetry. These are concerted reactions and lead to the product cyclobutane directly. These reaction pathways were analyzed on the basis of simple electron configuration models by the CiLC‐IRC method. The [2s + 2s] reaction of D2h occurs in a very small region near the transition state, and the [2s + 2s] reaction of C2v occurs in two steps. However, there are no energy minimum points between these steps. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
1,5‐hydrogen shifts in methyl‐1,3‐cycloheptadienes
Authors: Hess B. Andes 
Published: October 2002

AbstractDensity functional calculations are performed on the isomeric methlyl‐1,3‐cycloheptadienes and the transition structures that link them via 1,5‐hydrogen shifts. A total of 18 stationary points were located, 10 minima and 8 transition structures. Many of the structures found are related conformationally. The results indicate that the isomerizations previously observed experimentally arise from antarafacial 1,5‐hydrogen shifts. The calculated relative energies and activation energies are in satisfactory agreement with those observed by Mironov. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Potential energy surface and ro‐vibrational energies of Ne in the ground electronic state
Authors: Šindelka Milan , Špirko Vladimír , Urban Jan , Mach Pavel , Leszczynski Jerzy 
Published: October 2002

AbstractA global potential energy surface of Ne in its ground electronic state is evaluated using a Rayleigh–Schrödinger version of the third‐order multireference many‐body perturbation theory (MR‐MBPT) in a complete model space. The ab initio data are fitted quantitatively to a model potential energy function expressed in the Jacobi coordinates, and the fitted function is used to evaluate the ro‐vibrational energies of Ne using the (bond length–bond angle) Sutcliffe–Tennyson (ST) and (hyperspherical) Yamashita–Morokuma–Leforestier (YML) approaches. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Static dipole and quadrupole polarizability of confined hydrogen atom with Z=N/3 (N=1–5)*
Authors: Sen K. D. , Mayer B. , Schmidt P. C. , Garza Jorge , Vargas Rubicelia , Vela Alberto 
Published: October 2002

AbstractFirst calculations of static dipole and quadrupole polarizability for the spherically confined hydrogen atom within the hard boundaries with nuclear charge Z=N/3, N=1–5, are carried out using the Sternheimer perturbation‐numerical procedure. The polarizability values strongly depend upon the radius of confinement. The polarizability calculations for the exotic hydrogenic ions with nuclear charges ⅓, ⅔, \documentclass{article}\pagestyle{empty}\begin{document}$\frac{4}{3}$\end{document}, and \documentclass{article}\pagestyle{empty}\begin{document}$\frac{5}{3}$\end{document} exhibit strong dependence on the radius of confinement and the nuclear charge. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Toward a computed peptide structure database: The role of a universal atomic numbering system of amino acids in peptides and internal hierarchy of database
Authors: Chass Gregory A. , Sahai Michelle A. , Law Jacqueline M. S. , Lovas Sandor , Farkas Ödön , Perczel Andras , Rivail Jean‐Louis , Csizmadia Imre G. 
Published: October 2002

AbstractWith the construction and implementation of a logical and standardized numbering of atomic nuclei, to define mono‐, di‐, and oligo‐peptide systems, automation of input file generation and data extraction could greatly improve the efficiency of the search for the structural energy minima on the potential energy hypersurface of these systems. The internal hierarchy of the database covering constitutional structures, protective groups, levels of theory, and basis sets used, as well as the variety of possible conformations, is also discussed. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
A generalized expansion of the potential energy of diatomic molecules
Authors: Molski Marcin , Konarski Jerzy 
Published: October 2002

AbstractA new generalized expansion of the Born–Oppenheimer potential energy of diatomic molecules, combining a power series with Padé approximant, is introduced. It converges in the range of internuclear separation R∈〈0,∞) and can be used to reduce infrared and microwave spectra to parameters of a diatomic effective Hamiltonian. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Magnetic‐field manipulation of chemical bonding in artificial molecules
Authors: Yannouleas Constantine , Landman Uzi 
Published: October 2002

AbstractThe effect of orbital magnetism on the chemical bonding of lateral, two‐dimensional artificial molecules is studied in the case of a 2e double quantum dot (artificial molecular hydrogen). It is found that a perpendicular magnetic field reduces the coupling (tunneling) between the individual dots and, for sufficiently high values, it leads to complete dissociation of the artificial molecule. The method used is building on Löwdin's work on projection operators in quantum chemistry; it is a spin‐and‐space unrestricted Hartree–Fock method in conjunction with the companion step of the restoration of spin and space symmetries via projection techniques (when such symmetries are broken). This method is able to describe the full range of couplings in two‐dimensional double quantum dots, from the strong‐coupling regime exhibiting delocalized molecular orbitals to the weak‐coupling and dissociation regimes associated with a generalized valence bond combination of atomic‐type orbitals localized on the individual dots. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Benzocyclobutadiene: The question of structures, magnetic shieldings, and aromatic character*
Authors: Jensen Morten Østergaard , Thorsteinsson Thorstein , Hansen Aage E. 
Published: October 2002

AbstractThe importance of electron correlation for structure and magnetic shielding of benzocyclobutadiene is studied using the [2,2]‐CASSCF, the [8,8]‐CASSCF, and the MP2 approaches. The study aims at the question of applicability of the terms aromatic or antiaromatic for classification of this system and at the assignment of the experimental hydrogen chemical shifts. As reference, results for benzene are also included. Optimized structures are reported, including the two, respectively, three roots at the two complete active space self‐consistent field (CASSCF) levels. For the ground state, electron correlation plays about the same role for structure and energy as it does for benzene, while the magnetic properties are sensitive to correlation, and are not entirely resolved at the present levels. The higher CASSCF roots correspond to inherently multiconfigurational states, and the magnetic results for the second molecular state indicate the necessity for higher level computations. The chemical shifts computed for the ground state are compatible with the experimental data, in contrast to a previous assignment associating the shifts with a molecular structure representing the second CASSCF root. Applying a criterion based on the perpendicular component of the shielding field, the ground state of benzocyclobutadiene qualifies for neither a global aromatic nor a global antiaromatic assignment. In a dichotomic classification, the six‐membered ring again qualifies for neither an aromatic nor an antiaromatic assignment, leaving open an antiaromatic assignment for the four‐membered ring, in accord with the reactivity of benzocyclobutadiene. We compare and discuss the assignments proposed here and in the literature in the light of a prevailing feeling of elusiveness shading the concept of aromaticy. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Stochastic diagonalization of Hamiltonian: A genetic algorithm‐based approach
Authors: Nandy Subhajit , Chaudhury Pinaki , Bhattacharyya S. P. 
Published: October 2002

AbstractWe propose and demonstrate the workability of a genetic‐algorithm‐based technique of finding the eigenvalues and eigenfunctions of a real symmetric Hamiltonian matrix. The algorithm can be tailored to extract all the eigenvalues at a time or to extract only the lowest or the highest eigenvalue first and then sequentially determine the next few higher (lower) eigenvalues. The algorithm is generalized to handle diagonalization problems in which the basis functions themselves are optimized simultaneously. Several model applications are reported. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Effects of size of noncovalent complexes on their stability during collision‐induced dissociation
Authors: Jellen Emily E. , Chappell Angelina M. , Ryzhov Victor 
Published: October 2002

AbstractThe size‐dependent stability of noncovalent complexes under collision‐induced dissociation (CID) conditions was studied on a quadrupole ion trap mass spectrometer. Complexes of heme, tetraphenylporphyrin iron(III) (TPP‐Fe), and tetraphenylporphyrin manganese(III) (TPP‐Mn) with several histidine‐containing peptides and model compounds were formed by electrospray ionization (ESI) and their stability was probed by variable‐energy CID. It was found that the stability of complexes with the same (or nearly the same) binding energy has a linear dependence on the complex size (or total number of degrees of freedom). This approach will allow comparisons of variable‐energy CID data for noncovalent complexes with different binding energies and could be used to help in structural elucidation of some complexes formed by multidentate ligands. The linearity of size effects on the stability of the complexes was also tested in three crown ether/protonated primary amine systems. Copyright © 2002 John Wiley & Sons, Ltd.
Multiple sprayer system for high‐throughput electrospray ionization mass spectrometry
Authors: Schneider Bradley B. , Douglas D. J. , Chen David D. Y. 
Published: October 2002

AbstractA multiple sprayer electrospray ion source for high‐throughput analysis is described. The ion source is comprised of multiple electrospray capillaries, each with an ion lens located near the tip. The electric potentials applied to the ion lenses are used to control the sprayers. The use of ion lenses eliminates the need for mechanical blocking devices to selectively enable or disable the sprayers, and results in a less expensive and more reliable set‐up. Sprayers can be enabled or disabled within approximately 50–250 ms when the lens potentials are controlled manually. For simultaneous operation of multiple electrospray capillaries, it is advantageous to orient the capillaries so that the spray from each passes directly in front of the entrance aperture of the mass spectrometer. Copyright © 2002 John Wiley & Sons, Ltd.
Liquid chromatography/mass spectrometric bioanalysis of a modified γ‐cyclodextrin (Org 25969) and Rocuronium bromide (Org 9426) in guinea pig plasma and urine: its application to determine the plasma pharmacokinetics of Org 25969
Authors: Epemolu Ola , Mayer Iain , Hope Frank , Scullion Paul , Desmond Paul 
Published: October 2002

AbstractA sensitive and specific liquid chromatography/mass spectrometry (LC/MS) method has been developed and validated for the quantification of the modified γ‐cyclodextrin Org 25969 and Rocuronium bromide (Roc or Org 9426) in the plasma and urine of guinea pigs. The assay was linear and reproducible over the range 25–10000 ng/mL for both compounds. The lowest limit of quantification (LLOQ) for both compounds in urine was 25 ng/mL. In plasma, the LLOQ was 25 ng/mL for Org 9426 and 50 ng/mL for Org 25969. The inter‐ and intra‐day variation was lower than 20%. The physicochemical properties of both compounds imposed different modes of extraction from plasma. The modified γ‐cyclodextrin was extracted by trifluoroacetic acid (TFA) precipitation while Rocuronium was extracted by acetonitrile precipitation. Both compounds were quantified in urine by direct injection onto the column. The LC/MS analyses of Org 25969 and Org 9426 were performed using two different assay conditions. It was not possible to quantify the complex of cyclodextrin and Roc as it dissociated on the LC column. The use of LC/MS conferred great advantage to the quantification of both Org 25969 and Org 9426, as they were not chromogenic enough to afford the sensitivity and specificity required for the assay. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of fluoropolymer films deposited by magnetron sputtering of poly(tetrafluoroethylene) and plasma polymerization of heptadecafluoro‐1‐decene (HDFD) on (100)‐oriented single‐crystal silicon substrates
Authors: Zhang Yan , Yang G. H. , Kang E. T. , Neoh K. G. , Huang Wei , Huan A. C. H. , Lai D. M. Y. 
Published: October 2002

AbstractFluoropolymer thin films have been deposited on (100)‐oriented single‐crystal silicon substrates via argon plasma sputtering of a poly(tetrafluoroethylene) (PTFE) target and plasma polymerization of 1H, 1H, 2H‐heptadecafluoro‐1‐decene (HDFD). The surface composition and molecular structure of the deposited fluoropolymer films were analysed by x‐ray photoelectron spectroscopy (XPS), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and Fourier transform infrared (FTIR) spectroscopy. The ToF‐SIMS spectrum of the sputter‐deposited PTFE (s‐PTFE) surface revealed a high concentration of oligomeric –(CF2)‐ segments, resembling that of the pristine PTFE surface. However, the ToF‐SIMS spectra of the plasma‐polymerized HDFD (pp‐HDFD) films showed the presence of oligomeric –(CF2)‐ segments with much shorter repeat units, in comparison with those of the pristine PTFE and s‐PTFE film. The XPS and FTIR results suggested that the surface composition and chemical structure of the pp‐HDFD film deposited at a high r.f. power were closer to those of the s‐PTFE film. Water contact angle and atomic force microscopy measurements indicated that both sputtering deposition and plasma polymerization could give rise to highly hydrophobic surfaces with good uniformity. Peel adhesion test results suggested that both the s‐PTFE and pp‐HDFD films were strongly tethered to the surface of Si substrates. Copyright © 2002 John Wiley & Sons, Ltd.
Nanoscale bimetallic catalysts: are they really bimetallic?
Authors: Guczi L. , Bazin D. , Schay Z. , Kovács I. 
Published: October 2002

AbstractThe existence of bimetallic particles (and their reducibility and location on/or in the support) in Ru–Co/NaY and Pt–Co/NaY samples has been studied by in situ X‐ray adsorption spectroscopy (XAS). It is established that in Ru–Co/NaY the monometallic clusters maintain their identity, whereas in Pt–Co/NaY the existence of small bimetallic particles can be established. In both cases the results are supported by other techniques, such as XPS and temperature‐programmed reduction. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and ionic exchanges of zeolites for gas adsorption
Authors: Beyaz Kayiran S. , Lamari Darkrim F. 
Published: October 2002

AbstractThe present study deals with hydrogen adsorption on forms of the sodium LTA (Na A) zeolite fully exchanged by potassium and lithium, and on their compacted forms. The Na A zeolite was synthesized by using the hydrothermal method, and its ionic exchange was obtained by successive contacts. Structural characterizations were evaluated using different methods. Adsorption isotherms were measured for hydrogen in Na A and in its exchanged forms at a temperature of 293 K and up to a pressure of 1 MPa. In this paper, we investigated the infrared spectroscopy of fully exchanged materials. The structure of the materials and their hydrogen adsorption capacity varied with the nature of the cations exchanged. Copyright © 2002 John Wiley & Sons, Ltd.
XPS characterization of adsorbed reaction intermediates on automotive exhaust gas catalysts: NO and CO + NO interactions with Pd
Authors: Mamede A.‐S. , Leclercq G. , Payen E. , Granger P. , Gengembre L. , Grimblot J. 
Published: October 2002

AbstractNitrous oxide (NO) adsorption and the CO + NO reaction have been investigated on bulk and alumina‐supported Pd catalysts by XPS at various temperatures between 25 and 300°C with PNO in the 0.5–5.0 (×10−2) atm range and PCO = 5 × 10−3 atm. A catalytic reactor settled in the preparation chamber coupled to the spectrometer allows surface changes occurring under catalytic conditions on these catalysts to be characterized. Various nitrogen‐containing species have been detected, which depend on the oxidation state of Pd. The results have been explained tentatively in the light of a mechanism proposed for NO transformation. Copyright © 2002 John Wiley & Sons, Ltd.