bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth factor‐mediated altered expression and regulation of S‐adenosylmethionine decarboxylase in a H‐ras transformed cell line capable of malignant progression
Authors: Hardin Marcus S. , Hurta Robert A. R. 
Published: August 2002

AbstractMammalian S‐adenosylmethionine decarboxylase (SAMDC) is a regulatory activity, which is involved in the biosynthesis of polyamines. The polyamines, namely putrescine, spermidine, and spermine, are essential for mammalian cell proliferation. SAMDC expression was examined in a H‐ras transformed cell capable of metastasis formation. Serum stimulation of these cells resulted in increased SAMDC mRNA and enzyme activity expression. The effect of several physiologically relevant growth factors on SAMDC expression was also determined. SAMDC mRNA expression was increased in response to epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) stimulation but was unaffected by transforming growth factor beta1 (TGF‐beta1) and platelet derived growth factor (PDGF). Increased SAMDC enzyme activity occurred in response to exposure to EGF, bFGF, TGF‐beta1, and PDGF. The EGF and bFGF mediated alterations in SAMDC mRNA expression were apparently not due to alterations in the transcriptional apparatus but occurred partly through post‐transcriptional mechanisms involving increased SAMDC message stability. EGF and bFGF were able both to cooperate with cycloheximide, an inhibitor of protein synthesis, to augment the expression of SAMDC mRNA. Furthermore, studies with NIH‐3T3 fibroblasts transfected with either the normal basic fibroblast growth factor coding sequence that lacks a known secretory signal sequence or a chimeric bFGF sequence that targets the growth factor to the secretory pathway revealed that increased SAMDC expression occurred only in those cells which contained the chimeric bFGF sequence that targets the growth factor to the secretory pathway suggesting that the increase in expression of SAMDC occurs through an autocrine mechanism. Increased ornithine decarboxylase (ODC) expression was found to occur in both types of bFGF transfected cells suggesting that altered ODC expression in response to bFGF stimulation may occur through both autocrine and intracrine mechanisms. In addition, a correlation was found to exist between SAMDC expression and regulation in response to growth factor stimulation and malignant potential. This correlation supports the view that growth factor induced alterations in SAMDC expression, although not sufficient on their own to induce metastasis, are important in the promotion and establishment of events important to the phenotype expressed by H‐ras transformed cells capable of malignant progression. J. Cell. Biochem. 84: 349–358, 2002. © 2001 Wiley‐Liss, Inc.
Oligovalent link atoms in embedding calculations
Authors: Krüger Thomas , Sax Alexander F. 
Published: August 2002

AbstractMaking reasonable statements about large systems is a notoriously difficult task of quantum chemistry. If such a system consists of a small but electronically important region, the core, which requires a treatment on a high level of theory, and a larger remainder, the bulk, which only acts in a perturbative fashion and thus admits a description on a lower level of theory, then it is appropriate to partition it accordingly and use an embedding scheme to provide for the coupling of the two regions. In many cases of said partitioning it will be necessary to cut covalent bonds so that the emerging free valences have to be saturated by link atoms. Mostly hydrogen atoms are used. However, it may be necessary to separate the entire system so that bulk atoms are generated that are bound to two or three core atoms at once, that is, such bulk atoms are divalent or even trivalent with respect to the core. In the present article we demonstrate by means of several silane molecules, ranging from Si3H8 to Si104H92, that the use of oligovalent link atoms is quite promising. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 371–377, 2002
Comprehensive relativistic ab initio and density functional theory studies on PtH, PtF, PtCl, and Pt(NH3)2Cl2
Authors: Liu Wenjian , Franke Robert 
Published: August 2002

AbstractPlatinum monohydride is taken as an example to compare the performance of various relativistic and correlation approaches, such as all‐electron DPT (direct perturbation theory), ECP (effective core potential); RSPT2, RSPT3 (second‐ and third‐order multireference Rayleigh–Schrödinger perturbation theory), CCSD(T) (coupled‐cluster with singles, doubles, and perturbative triples), as well as the four‐component relativistic density functional theory. It is shown that first‐order DPT performs significantly better than the (first‐order) Breit–Pauli Hamiltonian. The performance of different approaches for the excitation energies of the platinum diatomics is discussed critically. The molecular spectroscopic constants for PtF and PtCl are predicted for the first time. The geometric data for several isomers of cis‐ and trans‐Pt(NH3)2Cl2 are reported. The corresponding energetic data are calculated at relativistic all‐electron and ECP‐CCSD(T) as well as four‐component relativistic density functional levels of theory. Contrary to previous results, it is found that the two C2v isomers of cis‐Pt(NH3)2Cl2 are marginally separated in energy, which could be ascribed to Cl—H interactions. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 564–575, 2002; DOI 10.1002/jcc.10030
The SGB/NP hydration free energy model based on the surface generalized born solvent reaction field and novel nonpolar hydration free energy estimators
Authors: Gallicchio Emilio , Zhang Linda Yu , Levy Ronald M. 
Published: August 2002

AbstractThe development and parameterization of a solvent potential of mean force designed to reproduce the hydration thermodynamics of small molecules and macromolecules aimed toward applications in conformation prediction and ligand binding free energy prediction is presented. The model, named SGB/NP, is based on a parameterization of the Surface Generalized Born continuum dielectric electrostatic model using explicit solvent free energy perturbation calculations and a newly developed nonpolar hydration free energy estimator motivated by the results of explicit solvent simulations of the thermodynamics of hydration of hydrocarbons. The nonpolar model contains, in addition to the more commonly used solvent accessible surface area term, a component corresponding to the attractive solute–solvent interactions. This term is found to be important to improve the accuracy of the model, particularly for cyclic and hydrogen bonding compounds. The model is parameterized against the experimental hydration free energies of a set of small organic molecules. The model reproduces the experimental hydration free energies of small organic molecules with an accuracy comparable or superior to similar models employing more computationally demanding estimators and/or a more extensive set of parameters. © 2002 Wiley Periodicals, Inc. J Comput Chem 5: 517–529, 2002; DOI 10.1002/jcc.10045
Ab initio study on the photochemical behavior of styrene
Authors: Amatatsu Yoshiaki 
Published: August 2002

AbstractAb initio complete active space self‐consistent field (CASSCF) and the second order multireference Møller‐Plesset calculations have been performed to examine the photochemical behavior of styrene upon the strong S0‐S2 electronic excitation in the low‐lying excited states. The optimized structure at the S2/S1 conical intersection (CIX) is characterized by a quinoid structure. The transition state (TS) in S1 is in the vicinity of the S2/S1‐CIX. At the S1‐TS, two reaction paths branch. One is the relaxation into the stable structure in S1 and then emission into S0. The other is the radiationless decay through the S1/S0‐CIX. © 2002 Wiley Periodicals, Inc. J Comput Chem 10: 950–956, 2002
Molecular mechanics calculations on carbonyl compounds. IV. Heats of formation
Authors: Langley Charles H. , Lii Jenn‐Huei , Allinger Norman L. 
Published: August 2002

AbstractMolecular mechanics (MM4) calculations on the heats of formation of aldehydes and ketones were carried out for a total of 59 compounds (10 aldehydes and 49 ketones). Optimization of the heat of formation parameters was obtained by a least squares fit to the experimentally known heats of formation. With the optimized MM4 heat of formation parameters, the MM4 calculated heats of formation showed significant improvement over those of MM3. The standard and weighted root mean square deviations for the MM4 values were 0.35 and 0.31 kcal mol−1, respectively, whereas for the MM3 values they were 0.42 and 0.39 kcal mol−1, respectively. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1476–1483, 2001
Ability of fullerenes to act as η6 ligands in transition metal complexes. A comparative PM3(tm)–density functional theory study
Authors: Goh Sor‐Koon , Marynick Dennis S. 
Published: August 2002

AbstractHigh‐quality DFT calculations are employed to estimate the arene exchange energies for reactions of general formula:

For C60 and C70 complexes of Cr(CO)3, full geometry optimizations at the DFT level using moderately large basis sets were performed, while for the other systems a hybrid approach was developed in which the geometries were obtained at the PM3(tm) level and the energetics were evaluated at the DFT level. C70 is shown to be a slightly better arene ligand than C60; however, no enhancements of arene‐like bonding capabilities are seen for C78 and C84 relative to C70. Explicit calculation of a series of exchange energies at the DFT level using both DFT and PM3(tm) geometries demonstrates that PM3(tm) geometries are sufficiently accurate for the calculation of energetics at a higher theoretical level, but PM3(tm) calculations are inadequate for a quantitative assessment of exchange energies. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1881–1886, 2001
Theoretical study on reaction mechanism of the CF radical with nitrogen dioxide
Authors: Tao Yu‐guo , Ding Yi‐hong , Liu Jian‐jun , Li Ze‐sheng , Huang Xu‐ri , Sun Chia‐Chung 
Published: August 2002

AbstractThe singlet potential energy surface of the [CFNO2] system is investigated at the B3LYP and CCSD(T) (single‐point) levels to explore the possible reaction mechanism of CF radical with NO2. The top attack of C‐atom of CF radical at the N‐atom of NO2 molecule first forms the adduct isomer FCNO2 1 followed by oxygen‐shift to give trans‐OC(F)NO 2 and then to cis‐OC(F)NO 3. Subsequently, the most favorable channel is a direct dissociation of 2 and 3 to product P1 FCO+NO. The second and third less favorable channels are direct dissociation of 3 to product P2 FNO+CO and isomerization of 3 to a complex NOFCO 4, which can easily dissociate to product P3 FON+CO, respectively. The large exothermicity released in these processes further drives most of the three products P1, P2, and P3 to take secondary dissociation to the final product P12 F+CO+NO. Another energetically allowed channel is formation of product P4 1NF+CO2, yet it is much less competitive than P1, P2, P3, and P12. The present calculations can well interpret one recent experimental fact that the title reaction is quite fast yet still much slower than the analogous reaction CH+NO2. Also, the results presented in this article may be useful for future product distribution analysis of the title reaction as well as for the analogous CCl and CBr reactions. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1907–1919, 2001
Current status of doctoral‐level training in psychological testing
Authors: Belter Ronald W. , Piotrowski Chris 
Published: August 2002

AbstractTraining directors of 82 American Psychological Association (APA)‐approved doctoral programs in clinical psychology responded to a survey on the current status and recent changes in doctoral training in psychological assessment. Although testing continues to be a major focus of training, a slight decline in emphasis on assessment was noted, most notably with projective techniques. With few exceptions (e.g., NEO‐PI, Personality Assessment Inventory), traditional tests were emphasized in coursework and also were considered “essential” for the practicing psychologist. Interestingly, there seems to be increased emphasis on the interview and neuropsychological testing compared to prior surveys of academic settings. Only 29% of the training directors reported that their programs have been significantly affected by managed care, suggesting that most academic programs are somewhat insulated from marketplace pressures. It is recommended that training programs balance their focus on traditional academic values with the realities of the clinical practice arena. © 2001 John Wiley & Sons, Inc. J Clin Psychol 57: 717–726, 2001.
Feelings in context: Countertransference and the real world in feminist therapy
Authors: Brown Laura S. 
Published: August 2002

AbstractThe concept of countertransference has been seen as problematic by feminist therapists. However, feminist therapy theory is intensely interested in the symbolic levels of the relationships between therapists and clients, with an emphasis on how the here and now social context informs and transforms those symbols. This article describes a feminist perspective on the therapist's symbolic relationships to clients, and the positive and challenging ramifications of those symbolic encounters. © 2001 John Wiley & Sons, Inc. J Clin Psychol/In Session 57: 1005–1012, 2001.
Toward an integrative perspective on resistance to change
Authors: Arkowitz Hal 
Published: August 2002

AbstractThis article presents an integrative perspective on resistance. The phenomena of resistance can be seen at the behavioral, interpersonal, cognitive, and affective levels. A set of integrative working assumptions is proposed in which resistance reflects meaningful information about clients' conflicts among various aspects of their selves relating to change. In this view, resistance is determined by intrapersonal and interpersonal factors and can occur with or without conscious awareness. Integrative approaches to working with these conflicts are described. © 2002 John Wiley & Sons, Inc. J Clin Psychol/In Session 58: 219–227, 2002.
Effects of calcium, calmodulin, protein kinase C and protein tyrosine kinases on volume‐activated taurine efflux in human erythroleukemia cells
Authors: Huang Chiun‐Chien , Chang Chirn‐Bin , Liu Jer‐Yuh , Basavappa Srisaila , Lim Poh‐Hong 
Published: August 2002

AbstractThe effects of calcium, calmodulin, protein kinase C (PKC) and protein tyrosine kinase (PTK) modulators were examined on the volume‐activated taurine efflux in the erythroleukemia cell line K562. Exposure to hypoosmotic solution significantly increased taurine efflux and intracellular calcium concentration ([Ca2+]i). The Ca2+ channel blockers La3+ (1 mM), verapamil (200 μM) and nifedipine (100 μM) inhibited the hypoosmotically‐induced [Ca2+]i increase by more than 90%, while the volume‐activated taurine efflux was inhibited by 61.3 ± 9.5, 74.1 ± 9.3 and 38.0 ± 1.5%, respectively. Furthermore, the calmodulin inhibitors W7 (50 μM) and trifluoperazine (10 μM) and the Ca2+/calmodulin‐dependent protein kinase II inhibitor KN‐62 (2 μM) significantly blocked the volume‐activated taurine efflux by 93.4 ± 2.7, 77.9 ± 3.5 and 61.3 ± 15.8%, respectively. In contrast, the PKC inhibitor staurosporine (200 nM) or the PKC activator phorbol 12‐myristate 13‐acetate (100 nM) did not have significant effects on the volume‐activated taurine efflux. However, pretreatment with PTK inhibitors genistein, tyrphostin A25, and tyrphostin A47 blocked the volume‐activated taurine efflux. These results suggest that the volume‐activated taurine efflux in K562 cells may not directly involve Ca2+, but may require the presence of calmodulin and/or PTK. © 2001 Wiley‐Liss, Inc.
Quantitative analysis of agonist‐dependent parathyroid hormone receptor trafficking in whole cells using a functional green fluorescent protein conjugate
Authors: Conway Bruce R. , Minor Lisa K. , Xu Jun Z. , D'Andrea Michael R. , Ghosh Richik N. , Demarest Keith T. 
Published: August 2002

AbstractMany G‐protein coupled receptors (GPCRs) undergo ligand‐dependent internalization upon activation. The parathyroid hormone (PTH) receptor undergoes endocytosis following prolonged exposure to ligand although the ultimate fate of the receptor following internalization is largely unknown. To investigate compartmentalization of the PTH receptor, we have established a stable cell line expressing a PTH receptor–green fluorescent protein (PTHR–GFP) conjugate and an algorithm to quantify PTH receptor internalization. HEK 293 cells expressing the PTHR–GFP were compared with cells expressing the wild‐type PTH receptor in whole‐cell binding and functional assays. 125I‐PTH binding studies revealed similar Bmax and kD values in cells expressing either the PTHR–GFP or the wild‐type PTH receptor. PTH‐induced cAMP accumulation was similar in both cell lines suggesting that addition of the GFP to the cytoplasmic tail of the PTH receptor does not alter the ligand binding or G‐protein coupling properties of the receptor. Using confocal fluorescence microscopy, we demonstrated that PTH treatment of cells expressing the PTHR–GFP conjugate produced a time‐dependent redistribution of the receptor to the endosomal compartment which was blocked by pretreatment with PTH antagonist peptides. Treatment with hypertonic sucrose prevented PTH‐induced receptor internalization, suggesting that the PTH receptor internalizes via a clathrin‐dependent mechanism. Moreover, co‐localization with internalized transferrin showed that PTHR–GFP trafficking utilized the endocytic recycling compartment. Experiments using cycloheximide to inhibit protein synthesis demonstrated that recycling of the PTHR–GFP back to the plasma membrane was complete within 1–2 h of ligand removal and was partially blocked by pretreatment with cytochalasin D, but not nocodazole. We also demonstrated that the PTH receptor, upon recycling to the plasma membrane, is capable of undergoing a second round of internalization, a finding consistent with a role for receptor recycling in functional resensitization. © 2001 Wiley‐Liss, Inc.
Use of various processes for pilot plant treatment of wastewater from a wood‐processing factory
Authors: Athanasopoulos Nikolaos S 
Published: August 2002

AbstractThe wastewater from a wood‐processing factory is characterized by a high COD, chlorides and nitrogen content. Various treatment processes were applied to treat this wastewater in pilot‐scale units. By applying one‐stage denitrification–activated sludge biological treatment it was not possible to remove nitrogen. Nitrification was inhibited by wastewater compounds. By applying a second stage of a nitrification biofilter it was possible to have a high degree of nitrification. The denitrification was complete. With biological methods the reduction of COD, and ${\bf NO_{3}^{-}}$‐N and ${\bf NH_{4}^{+}}$‐N concentrations to acceptable values was not achievable. Physical–Chemical methods as H2O2/UV, electrolysis and ozonation were used as post‐treatment of effluents from the biological system. Radical degradation, initiated by the powerful hydroxyl radicals which are generated from H2O2 by UV activation, is used for wastewater post‐treatment. The combination of H2O2/UV was not suitable for post‐treatment of this wastewater. With electrolysis, ${\bf NH_{4}^{+}}$‐N and COD removal can be complete. The total amount of ammonia and organic nitrogen converted to nitrate nitrogen for current density of 1.15 Adm−2 and energy consumption of 71.6 kWhm−3 was 0.35 gdm−3. Further biological denitrification is required for ${\bf NO_{3}^{-}}$‐N removal to permitted values. Energy consumption for the elimination of 1 kg COD was 40.4 kWh and 35.8 kWh for current densities of 0.7 Adm−2 and 1.15 Adm−2 respectively. The energy required to reach the limit value of COD equal to 150 mgdm−3 for current density of 1.15 Adm−2 was 71.6 kWhm−3. With ozonation, the COD removal can be complete. Further biological nitrification–denitrification is required to remove ${\bf NH_{4}^{+}}$‐N and ${\bf NO_{3}^{-}}$‐N to permitted values. At pH 7.0, in order to reach the limit value of COD equal to 150 mgdm−3, specific ozone dose was 6.0 g per g of COD removed and the total amount of ammonia and organic nitrogen converted to nitrate nitrogen was 0.25 gdm−3. The total equivalent energy required is estimated to be 75.0 kWhm−3.© 2001 Society of Chemical Industry
Sensitivity analysis in oxidation ditch modelling: the effect of variations in stoichiometric, kinetic and operating parameters on the performance indices
Authors: Abusam A , Keesman K J , van Straten G , Spanjers H , Meinema K 
Published: August 2002

AbstractThis paper demonstrates the application of the factorial sensitivity analysis methodology in studying the influence of variations in stoichiometric, kinetic and operating parameters on the performance indices of an oxidation ditch simulation model (benchmark). Factorial sensitivity analysis investigates the sensitivities in a region rather than in a point. Hence, it has the advantage of giving more information about parameter interactions (non‐linearity). Short‐term results obtained have shown the following. The index AE is not significantly affected by variations in the value of parameters of the activated sludge model (ASM) No 1. The index TSP is greatly influence by heterotrophic yield (YH), heterotrophic decay (bH) and specific hydrolysis (kh) and the index EQ is dominated by YH, Monod coefficient (KS), bH, kh, anoxic condition correction factors (ηg, ηh), hydrolysis half‐saturation coefficient (KX), autotrophs maximum specific growth rate (µA) and ammonia half‐saturation coefficient (KNH). Furthermore, the index EQ has been shown to be very sensitive to parameter interactions, at certain regions.© 2001 Society of Chemical Industry
Experimentation of a new mode of batch culture for lactic acid bacteria: cell reuse with an initial period of cell reactivation at acidic pH
Authors: Amrane Abdeltif 
Published: August 2002

AbstractCell reuse was compared with conventional batch culture for lactic acid fermentation, the objective was to simplify the batch process and to alleviate the need for added nitrogen. At high levels of nitrogen supplementation to the culture medium (20 g dm−3 yeast extract and 5 g dm−3 each of tryptic and pancreatic casein peptones), similar mean production rates were obtained with partial cell reuse and the conventional batch process, without any additional gain when cells were initially reactivated at acidic pH. On the other hand, cell reuse with an initial period without pH control appeared particularly effective for low levels of nitrogen supplementation (5 g dm−3 yeast extract): a 57% increase in the mean production rate with regard to the conventional batch process was obtained.© 2001 Society of Chemical Industry