bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accelerated aging studies of UHMWPE. II. Virgin UHMWPE is not immune to oxidative degradation
Authors: Edidin A. A. , Villarraga M. L. , Herr M. P. , Muth J. , Yau S. S. , Kurtz S. M. 
Published: August 2002

AbstractIn Part I of this series, we showed that aging at elevated oxygen pressure is more successful at increasing the depth to which degradation occurs although it, too, generally causes greater degradation at the surface than at the subsurface. Therefore we hypothesized that thermal degradation alone, in the absence of free radicals, could be sufficient to artificially age UHMWPE in a manner analogous to natural aging. In the present study, virgin and air‐irradiated UHMWPE (extruded GUR 1050 and compression‐molded 1900) were aged up to 4 weeks at elevated oxygen pressure, and the mechanical behavior at the surface and subsurface was examined. All the materials were substantially degraded following 4 weeks of aging, but the spatial variations in the nonirradiated materials more closely mimicked the previously observed subsurface peak of degradation seen in naturally aged UHMWPE following irradiation in air. This aged material could provide a more realistic model for subsurface mechanical degradation, making it suitable for further mechanical testing in venues such as wear simulation. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 323–329, 2002
Visible‐light‐induced surface graft polymerization via camphorquinone impregnation technique
Authors: Ziani‐Cherif Houcine , Abe Yusuke , Imachi Kou , Matsuda Takehisa 
Published: August 2002

AbstractA surface modification method that is particularly applicable to complexly shaped fabricated devices has long been awaited. In this article, we describe the visible‐light‐induced surface photograft polymerization technique by which an inner surface of the device is modified by visible‐light irradiation through the external surface. Comphorquione, as a photoradical initiator, was impregnated on a segmented polyurethane surface by solvent soaking, followed by visible‐light irradiation in the presence of monomers such as acrylamide and poly(ethylene glycol) methacrylate. The resultant surfaces were highly wettable with water, and surface chemical compositional analysis by X‐ray photoelectron spectroscopy revealed that the surface was graft‐polymerized with these monomers. The simple and widespread applicability of this surface modification technique to biomedical devices is discussed. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 386–389, 2002
Depletion of mitochondrial DNA and enzyme in estrogen‐induced hamster kidney tumors: A rodent model of hormonal carcinogenesis
Authors: Bhat Hari K. 
Published: August 2002

AbstractMitochondrial DNA (mtDNA) encodes for 13 polypeptides critical for normal functioning of the electron transport chain and damage to mtDNA has been associated with aging, and implicated in several disease processes. Although damage to mtDNA is being implicated in mutagenesis and carcinogenesis, there are limited studies demonstrating the role and extent of mtDNA damage in human or rodent cancers. Using serial dilution and competitive polymerase chain reaction analysis, we have quantitated the amount of total mtDNA and analyzed the extent of mtDNA damage in estrogen‐induced and estrogen‐dependent hamster kidney tumors. The hamster kidney tumor model is a useful and widely investigated rodent model of hormonal carcinogenesis, which shares several characteristics with human breast and uterine cancers, and point to a common mechanistic pathway. Our data indicate a significant decrease in the copy number of total mtDNA and the activity of a nuclear‐encoded mitochondrial enzyme citrate synthase in hamster kidney tumors compared to age‐matched controls. Since there are several hundred mitochondria in a cell and each mitochondrion has multiple copies of mtDNA, a very small percentage of somatic deletion mutation may not be enough to result in a decreased capacity of the mitochondrial genome. However, a significant increase in deletion mutations or a decrease in the mtDNA copy number can result in a decreased oxidative phosphorylation capacity of the mitochondria and decreased energetics, and thus increased susceptibility to the disease process. Therefore, estrogen‐induced hamster kidney tumor model can be a useful rodent model of carcinogenesis to understand the role of mtDNA damage in cancer progression and development. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:1–9, 2002; DOI 10.1002/jbt.10017
The effect of dichloroacetic acid and trichloroacetic acid on DNA methylation and cell proliferation in B6C3F1 mice
Authors: Ge Rongrong , Yang Siming , Kramer Paula M. , Tao Lianhui , Pereira Michael A. 
Published: August 2002

AbstractThe chlorine disinfection by‐products, dichloroacetic acid (DCA) and trichloroacetic acid (TCA), are carcinogenic in mouse liver. We have previously reported that DCA and TCA induced DNA hypomethylation in mouse liver. In the present study, we determined the temporal association for DNA hypomethylation and cell proliferation. Female B6C3F1 mice were administered daily doses of 500 mg/kg DCA or TCA by gavage and sacrificed at 24, 36, 48, 72, and 96 hours after the first dose. The proliferating cell nuclear antigen‐labeling index in the liver was increased at 72 and 96 hours by both DCA and TCA, that is, at 72 hours the index was 1.00 ± 0.21, 0.51 ± 0.11, and 0.095 ± 0.016 for DCA, TCA, and the vehicle control, respectively. The mitotic index was also significantly increased at 96 hours. The promoter region for the c‐myc gene was hypomethylated only at 72 and 96 hours and not at the earlier sacrifices. Similarly, the methylation of the c‐myc gene in the kidney and urinary bladder was decreased only at 72 and 96 hours. In summary, enhancement of cell proliferation and decreased methylation of the c‐myc gene were first observed simultaneously at 72 hours after the start of exposure. Thus, the results support the hypothesis that DCA and TCA induce DNA hypomethylation by inducing DNA replication and preventing the methylation of the newly synthesized strands of DNA. © 2001 John Wiley & Sons, Inc. J Biochem Mol Toxicol 15:100–106, 2001
Grb2 dominantly associates with dynamin II in human hepatocellular carcinoma HepG2 cells
Authors: Yoon Sun Young , Jeong Moon‐Jin , Yoo Jiyun , Lee Kyung Im , Kwon Byoung‐Mok , Lim Do‐Seon , Lee Choong‐Eun , Park Young‐Mee , Han Mi Young 
Published: August 2002

AbstractThe two SH3 domains and one SH2 domain containing adaptor protein Grb2 is an essential element of the Ras signaling pathway in multiple systems. The SH2 domain of Grb2 recognizes and interacts with phosphotyrosine residues on activated tyrosine kinases, whereas the SH3 domains bind to several proline‐rich domain‐containing proteins such as Sos1. To define the difference in Grb2‐associated proteins in hepatocarcinoma cells, we performed coprecipitation analysis using recombinant GST‐Grb2 fusion proteins and found that several protein components (p170, p125, p100, and p80) differently associated with GST‐Grb2 proteins in human Chang liver and hepatocarcinoma HepG2 cells. Sos1 and p80 proteins dominantly bind to Grb2 fusion proteins in Chang liver, whereas p100 remarkably associate with Grb2 in HepG2 cells. Also GST‐Grb2 SH2 proteins exclusively bound to the p46Shc, p52Shc, and p66Shc are important adaptors of the Ras pathway in HepG2 cells. The p100 protein has been identified as dynamin II. We observed that the N‐SH3 and C‐SH3 domains of Grb2 fusion proteins coprecipitated with dynamin II besides Sos1. These results suggest that dynamin II may be a functional molecule involved in Grb2‐mediated signaling pathway on Ras activation for tumor progression and differentiation of hepatocarcinoma cells. J. Cell. Biochem. 84: 150–155, 2002. © 2001 Wiley‐Liss, Inc.
Variational treatment of the vibrational Hamiltonian for NH3 and H2NO
Authors: Marsal Philippe , Roche Michel 
Published: August 2002

AbstractThe full vibrational Hamiltonian for the inversion of NH3 and H2NO has been diagonalized in a basis set that is the direct product of functions of the inversion coordinate and of harmonic vibrational functions independent of this inversion coordinate. The kinetic part of the Hamiltonian matrix is constructed with the use of the closure relation for these vibrational functions. The method is tested with the potential function which is supposed to be harmonic for the vibrations orthogonal to the inversion coordinate: the first computed levels are in good agreement with experimental levels for NH3. For higher levels, anharmonic terms should be included. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 541–547, 2002; DOI 10.1002/jcc.10033
Ab Initio calculations of the stabilization energies of the conformational and the structural isomers of C3H7X where X = F, Cl, and Br
Authors: Helal Mustafa R. , Yousef Yaser A. , Afaneh Akef T. 
Published: August 2002

AbstractHF, MP2, and B3LYP calculations with different basis sets have been used in the computation of the stabilization energies of C3H7X isomers, where X is F, Cl, and Br. The experimental stabilization energies of the structural isomers of C3H7Cl and C3H7Br have been reproduced via B3LYP calculations. However, the calculated stabilization energies of fluoropropane isomers from their reported enthalpies of formation have been reproduced in all methods of calculations in present work. The experimental relative stabilities of the gauche conformers of 1‐fluoro‐, 1‐chloro‐, and 1‐bromopropanes have been also reproduced via some of the used calculations in the present work. The effect of the geminal interactions on X atomic charges and on the C–X and C–C bond lengths in halopropane isomers are also discussed. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 966–976, 2002
Theoretical study on the mechanism of the 1CHCl + NO reaction
Authors: Liu Jian‐Jun , Ding Yi‐Hong , Tao Yu‐Guo , Feng Ji‐Kang , Sun Chia‐Chung 
Published: August 2002

AbstractThe complex doublet potential energy surface of the CHClNO system, including 31 minimum isomers and 84 transition states, is investigated at the QCISD(T)/6‐311G(d, p)//B3LYP/6‐31G(d, p) level in order to explore the possible reaction mechanism of the singlet CHCl with NO. Various possible isomerization and dissociation channels are probed. The initial association between 1CHCl and NO at the terminal N‐site can almost barrierlessly lead to the chainlike adducts HClCNO a (a1, a2.) followed by the direct Cl‐extrusion to product P9 Cl + HCNO, which is the most feasible channel. Much less competitively, a (a1, a2) undergoes a ring‐closure leading to the cyclic isomer c‐C(HCl)NO d followed by a concerted Cl‐shift and NO cleavage of d to form the branched isomers ClNC(H)O f (f1, f2). Eventually, f (f1, f2) may take a direct H‐extrusion to produce P7 H + ClNCO or a concerted 1,2‐H‐shift and Cl‐extrusion to form P1 Cl + HNCO. The low‐lying products P2 HCl + NCO, P3 Cl + HOCN, P14 HCO + 3NCl, P6 ClO + HCN, and P13 ClNC + OH may have the lowest yields observed. Our calculations show that the product distributions of the title reaction are quite different from those of the analogous 1CHF + NO reaction, yet are similar to those of another analogous 3CH2 + NO reaction. The similarities and discrepancies among the three reactions are discussed in terms of the substitution effect. The present article may assist in future experimental identification of the product distributions for the title reaction and may be helpful for understanding the halogenated carbene chemistry. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 625–649, 2002
Energy‐based reconstruction of a protein backbone from its α‐carbon trace by a Monte‐Carlo method
Authors: Kaźmierkiewicz Rajmund , Liwo Adam , Scheraga Harold A. 
Published: August 2002

AbstractAn automatic procedure is proposed for reconstruction of a protein backbone from its Cα‐trace; it is based on optimization of a simplified energy function of a peptide backbone, given its α‐carbon trace. The energy is expressed as a sum of the energies of interaction between backbone peptide groups that are not neighbors in the sequence, the energies of local interactions within all amino acid residues, and a harmonic penalty function accounting for the conservation of standard bond angles. The energy of peptide group interactions is calculated using the assumption that each peptide group acts as a point dipole. For local interaction energy, use is made of a two‐dimensional Fourier series expansion of the energies of model terminally blocked amino acid residues, calculated with the Empirical Conformational Energy Program for Peptides (ECEPP/3) force field in the angles λ(1) and λ(2) defining the rotation of peptide groups adjacent to a Cα carbon atom about the corresponding Cα … Cα virtual‐bond axes. To explore all possible rotations of peptide groups within a fixed Cα‐trace, a Monte Carlo search is carried out. The initial λ angles are calculated by aligning the dipoles of the peptide groups that are close in space, subject to the condition of favorable local interactions. After the Monte Carlo search is accomplished with the simplified energy function, the energy of the structure is minimized with the ECEPP/3 force field, with imposition of distance constraints corresponding to the initial Cα‐trace geometry. The procedure was tested on model α‐helices and β‐sheets, as well as on the crystal structure of the immunoglobulin binding protein (PDB code: 1IGD, an α/β protein). In all cases, complete backbone geometry was reconstructed with a root‐mean‐square (rms) deviation of 0.5 Å from the all‐atom target structure. © 2002 Wiley Periodicals, Inc. J Comput Chem 7: 715–723, 2002
Computation of pressure components due to Class II force fields
Authors: Carpenter John E. 
Published: August 2002

AbstractIt has been shown that purely angle dependent terms in a force field do not contribute to the total pressure in a molecular simulation. However, this is not the case for the individual components of the pressure tensor, and is also untrue for crossterms in the force field including bond stretch. In this article, we show that virial contributions to the pressure tensor are easily computed in terms of bond distance vectors and atom forces for the bond topologies present in a Class II force field. Results from a simulation of a phospholipid biomembrane using the cff97 force field show that angle and torsional crossterms make a significant contribution to the pressure tensor. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 667–672, 2002
Quantum bits with polyacetylene
Authors: Da Silva Andre Elvas Pereira , E Silva Geraldo Magela 
Published: August 2002

AbstractThe dynamics of a polyacetylene single chain as a system for possible physical implementations of quantum bits is determined. This novel proposition is studied by varying intensity and duration of application of an electric field as well as the intensity, number, and position in the polymer chain of impurity molecules. The behavior of soliton pairs, whose associated energy levels form the quantum bit, is analyzed. The chain is modeled by a modified Pariser–Parr–Pople Hamiltonian extended to include the effects of an external electric field and the parameters of the impurity molecules. The effect of the variation of the field and impurities on the separation of the energy levels associated with soliton pairs is analyzed by numerical integration of the equations of motion. Two different approaches for controlling the separation of levels are presented, and their features compared. First, the use of changes in the electric field to control the distance (and ultimately coupling) between two solitons moving freely on the chain or captured by the potential generated by the impurity molecules. Second, the change in the intensity of the impurities alone, with no application of an external field. We have found that the effect of the use of the field on the separation of levels is much smaller than the one obtained by changes in the parameters of the impurity molecules, which eventually led us to achieve quantum bit behavior in a polyacetylene chain. The influence of the field and impurity parameters in the energy levels is determined, as well as their role in the coupling of the two solitons on the chain. Critical values for distance between solitons, intensity of field, and impurities that determine whether a pair of solitons can work as a quantum bit are obtained. © 2002 Wiley Periodicals, Inc. J Comput Chem 9: 870–873, 2002
Ab initio study on the electronic structures of styrene in the Franck‐Condon region
Authors: Amatatsu Yoshiaki 
Published: August 2002

AbstractThe electronic structures of styrene in the Franck‐Condon region have been theoretically examined by means of ab initio complete active space self‐consistent field (CASSCF) and the second order multireference Møller‐Plesset calculations. The optimized structure of styrene in S0 is planar but the torsional motion of the phenyl group is very floppy. The S1 state is assigned to the local π–π* excitation within the benzene ring. On the other hand, S2, above S1 by 0.561 eV, is assigned to a state that resembles the so‐called V‐state of ethylene. The transition intensity of S0–S1 is weak, while that of S0–S2 is strong. This is in good agreement with the experimental absorption spectrum where the S0–S1 and S0–S2 transitions are in the energy range of 290–220 nm. The optimized geometry of S1, characterized by an enlarged benzene ring and its vibrational analyses, further justifies the assignment of the S1 state. © 2002 Wiley Periodicals, Inc. J Comput Chem 9: 928–937, 2002
Analytical energy gradient evaluation in relativistic and nonrelativistic density functional calculations
Authors: Wang Fan , Li Lemin 
Published: August 2002

AbstractThe expressions of analytical energy gradients in density functional theory and their implementation in programs are reported. The evaluation of analytical energy gradients can be carried out in the fully 4‐component relativistic, approximate relativistic, and nonrelativistic density functional calculations under local density approximation or general gradient approximation with or without frozen core approximation using different basis sets in our programs. The translational invariance condition and the fact that the one‐center terms do not contribute to the energy gradients are utilized to improve the calculation accuracy and to reduce the computational effort. The calculated results of energy gradients and optimized geometry as well as atomization energies of some molecules by the analytical gradient method are in very good agreement with results obtained by the numerical derivative method. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 920–927, 2002
Exact Gaussian expansions of Slater‐type atomic orbitals
Authors: Gomes André Severo Pereira , Custodio Rogério 
Published: August 2002

AbstractThree exact Slater‐type function (STO) integral transforms are presented. The STO‐NG basis set can then be developed using either only 1s Gaussian functions, the same Gaussian exponents for each shell, or using the first Gaussian of each symmetry. The use of any of these three alternatives depends only on appropriate numerical integration techniques. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1007–1012, 2002
A quasi‐symmetric 2‐(49,9,6) design
Authors: Harada Masaaki , Munemasa Akihiro 
Published: August 2002

AbstractHuffman and Tonchev discovered four non‐isomorphic quasi‐symmetric 2‐(49,9,6) designs. They arise from extremal self‐dual [50,25,10] codes with a certain weight enumerator. In this note, a new quasi‐symmetric 2‐(49,9,6) design is constructed. This is established by finding a new extremal self‐dual [50,25,10] code as a neighbor of one of the four extremal codes discovered by Huffman and Tonchev. A number of new extremal self‐dual [50,25,10] codes with other weight enumerators are also found. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 173–179, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10007
Superpure digraph designs
Authors: Hartmann Sven 
Published: August 2002

AbstractA digraph design is a decomposition of a complete (symmetric) digraph into copies of pre‐specified digraphs. Well‐known examples for digraph designs are Mendelsohn designs, directed designs or orthogonal directed covers. A digraph design is superpure if any two of the subdigraphs in the decomposition have no more than two vertices in common. We give an asymptotic existence theorem for superpure digraph designs, which is a variation of an earlier result of Lamken and Wilson J Combin Theory Ser A 89: 149–200, 2000. As an immediate consequence, we obtain new results for supersimple designs and pure perfect Mendelsohn designs. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 239–255, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10013
One‐factorizations of complete multigraphs and quadrics in PG(n,q)
Authors: Kiss Gy. 
Published: August 2002

AbstractA new infinite family of simple indecomposable one‐factorizations of the complete multigraphs is constructed by using quadrics of finite projective spaces. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 139–143, 2002; DOI 10.1002/jcd.997
Psychotherapy for health and lifestyle change
Authors: Feinstein Robert E. , Feinstein Marilyn Sommer 
Published: August 2002

AbstractHealth practitioners use various models for facilitating health or lifestyle change, which entails either stopping an unhealthy behavior or promoting a new healthy behavior. Four models offer evidence‐based, systematic, and integrative approaches to lifestyle change. They are: the Transtheoretical Model or Stages of Change; Brief Motivational Interviewing; Prevention Oriented Primary Care; and the ECBIS Psychotherapy Model (Emotion, Cognition, Behavioral, Interpersonal, and System). This article reviews each model and features a case illustration to demonstrate how these models can be integrated and applied clinically to help a patient change multiple health behaviors. © 2001 John Wiley & Sons, Inc. J Clin Psychol/In Session 57: 1263–1275, 2001.
Pain and emotion: New research directions
Authors: Keefe Francis J. , Lumley Mark , Anderson Timothy , Lynch Thomas , Studts Jamie L. , Carson Kimi L. 
Published: August 2002

AbstractOriginally published in J Clin Psychol 57: 587–607, 2001.Through an oversight, Jamie Studts had previously not been listed as an author of this article in the special issue entitled “Psychological Treatment of the Patient with Chronic Disease.”The editors apologize for the omission.