bluuebunny/crossref_metadata_2025_split huggingface dataset:
Does PSA play a role as a promoting agent during the initiation and/or progression of prostate cancer?
Authors: Williams Simon A. , Singh Pratap , Isaacs John T. , Denmeade Samuel R. 
Published: December 2006

AbstractProstate cancer cells, like normal prostate epithelial cells, produce high levels of the differentiation marker and serine protease prostate‐specific antigen (PSA). PSA is used extensively as a biomarker to screen for prostate cancer, to detect recurrence following local therapies, and to follow response to systemic therapies for metastatic disease. While much is known about PSA's role as a biomarker, only a relatively few studies address the role played by PSA in the pathobiology of prostate cancer. Autopsy studies have documented that not only do prostate cancer cells maintain production of high amounts of PSA but they also maintain the enzymatic machinery required to process PSA to an enzymatically active form. A variety studies performed over the last 10 years have hinted at a role for PSA in growth, progression, and metastases of prostate cancer. A fuller understanding of PSA's functional role in prostate cancer biology, however, has been hampered by the lack of appropriate models and tools. Therefore, the purpose of this review is not to address issues related to PSA as a biomarker. Instead, by reviewing what is known about the genetics, biochemistry, and biology of PSA in normal and malignant prostate tissue, insights may be gained into the role PSA may be playing in the pathobiology of prostate cancer that can connect measurement of this biomarker to an understanding of the underlying etiology and progression of the disease. Prostate 67:312–329, 2007. © 2006 Wiley‐Liss, Inc.
Trapping choline oxidase in a nonfunctional conformation by freezing at low pH
Authors: Hoang Jane V. , Gadda Giovanni 
Published: December 2006

AbstractCholine oxidase is a flavin‐dependent enzyme that catalyzes the oxidation of choline to glycine–betaine, with oxygen as electron acceptor. Storage at pH 6 and −20°C resulted in a change in the conformation of choline oxidase, which was associated with complete loss of catalytic activity when the enzyme was assayed at pH 6. Incubation of the inactive enzyme at pH values ≥6.5 and 25°C resulted in a fast and partial reactivation of the enzyme, which occurred with slow onset of steady state during enzymatic turnover. The rate of approaching steady state was independent of the concentrations of choline and enzyme, but increased to a limiting value with increasing pH, defining a pKa value of ∼7.3 for an unprotonated group required for enzyme activation. Prolonged incubation of the inactive enzyme at pH 6 and temperatures ≥20°C, at which no hysteretic behavior was observed, resulted in the slow and full recovery of activity over 3 h, associated with a conformational change that reverted the enzyme to the native form. Activation of the enzyme at pH 6 was enthalpy‐driven with ΔH‡ and TΔS‡ values of ∼112 kJ mol−1 and ∼20 kJ mol−1 determined at 25°C. These data suggest that freezing the enzyme at low pH induces a localized and reversible conformational change that is associated with the complete and reversible loss of catalytic activity. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Destabilization of transthyretin by pathogenic mutations in the DE loop
Authors: Takeuchi Makoto , Mizuguchi Mineyuki , Kouno Takahide , Shinohara Yoshinori , Aizawa Tomoyasu , Demura Makoto , Mori Yoshihiro , Shinoda Hiroyuki , Kawano Keiichi 
Published: December 2006

AbstractTransthyretin single‐amino‐acid variants are responsible for familial amyloidotic polyneuropathy, in which transthyretin variants accumulate extracellularly in the form of fibrillar aggregates. We studied the structural stabilities of four transthyretin variants (L58H, L58R, T59K, and E61K), in which a positively charged amino acid is introduced in a loop region between the D‐ and E‐strands. In addition to being located in the DE‐loop, L58 and T59 are involved in the core of the transthyretin monomer. The L58H, L58R, and T59K substitutions destabilized transthyretin more than the E61K mutation did, indicating that transthyretin is substantially destabilized by the substitution of residues located in both the DE‐loop and the monomer core. By utilizing hydrogen‐deuterium exchange and nuclear magnetic resonance, we demonstrated that residues in the G‐strand and the loop between the A‐ and B‐strands were destabilized by these pathogenic mutations in the DE loop. At the quaternary structural level, the DE‐loop mutations destabilized the dimer–dimer contact area, which may lead to transient dissociation into a dimer. Our results suggest that the destabilization of the dimer–dimer interface and the monomer core is important for the amyloidogenesis of transthyretin. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Assessment of QoI resistance in Plasmopara viticola oospores
Authors: Toffolatti Silvia L , Serrati Luca , Sierotzki Helge , Gisi Ulrich , Vercesi Annamaria 
Published: December 2006

AbstractQoI fungicides, inhibitors of mitochondrial respiration at the Qo site of cytochrome b in the mitochondrial bc1 enzyme complex, are commonly applied in vineyards against Plasmopara viticola (Berk. & MA Curtis) Berl. & De Toni. Numerous treatments per year with QoI fungicides can lead to the selection of resistant strains in the pathogen population owing to the very specific and efficient mode of action. In order to evaluate the resistance risk and its development, two different methods, biological and molecular, were applied to measure the sensitivity of oospores differentiated in vineyards, both treated and untreated with azoxystrobin, from 2000 to 2004. Assays using oospores have the advantage of analysing the sensitivity of bulked samples randomly collected in vineyards, describing accurately the status of resistance at the end of the grapevine growing season. Both methods correlated well in describing the resistance situation in vineyards. QoI resistance was not observed in one vineyard never treated with QoI fungicides. In the vineyard where azoxystrobin had been used in mixture with folpet, the selection of QoI‐resistant strains was lower, compared with using solely QoI. In vineyards where QoI treatments have been stopped, a decrease in resistance was generally observed. Copyright © 2006 Society of Chemical Industry
Electronic structure of CuAlO2 and CuScO2 delafossites under pressure
Authors: Gilliland S. , Pellicer‐Porres J. , Segura A. , Muñoz A. , Rodríguez‐Hernández P. , Kim D. , Lee M. S. , Kim T. Y. 
Published: December 2006

AbstractThe electronic structure of CuAlO2 and CuScO2 delafossites is investigated by means of optical absorption measurements under pressure and ab initio band structure calculations. Measurements are carried out on CuAlO2 monocrystals and pulsed laser deposited CuAlO2 and CuScO2 thin films up to 20 GPa. CuAlO2 is an indirect semiconductor that is stable in the pressure range explored here. The pressure coefficients of the indirect and direct gaps are found to be 15 meV/GPa and 2 meV/GPa respectively. CuScO2 is a direct semiconductor and the pressure coefficient of the excitonic peak energy is –5.5 meV/GPa. Two reversible phase transitions are observed in CuScO2. At 13 GPa the delafossite structure becomes unstable and an unidentified intermediate high pressure phase is observed, which coexists with the delafossite phase up to 18 GPa. The intermediate phase is also a wide gap semiconductor, with an step‐like absorption edge at the energy of 3.42 ± 0.02 eV at 14.0 GPa and a positive pressure coefficient. Above 18 GPa, the absorption edge becomes structureless and its form seems to be that of an indirect gap. In the downstroke, the same sequence of changes is observed, with a hysteresis of about 4 GPa, confirming the structural nature of the transitions. These results are interpreted in the light of theoretical ab initio band structure calculations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrahigh‐pressure effects in metallo‐organics
Authors: Kagoshima Seiichi , Kondo Ryusuke , Matsushita Nobuyuki , Higa Momoka , Ovsyannikov Sergey V. , Shaydarova Nadezhda A. , Shchennikov Vladimir V. , Manakov Andrey Y. , Likhacheva Anna Y. 
Published: December 2006

AbstractThe results are reported of the pressure (P) dependence of the electrical resistance (R), the thermoelectric power (Seebeck effect) (S), and compressibility as well as the time dependence of R at fixed P up to 20 GPa for four metallo‐organics based on the BEDT‐TTF (bisethylenedithiolo‐tetrathiofulvalene) group, θ ‐(BEDT‐TTF)2CsZn(SCN)4, α ‐(BEDT‐TTF)2I3, β ′‐(BEDT‐TTF)2PF6, and (BEDT‐TTF)‐TCNQ. X‐ray powder and single‐crystal diffraction studies were also made on θ ‐(BEDT‐TTF)2CsZn(SCN)4 at high pressures up to P ∼ 10 GPa. The R values of all the crystals decreased with pressure up to P ∼ 3–5 GPa (low‐pressure regime), and then the sign of dR /dP inverted (high‐pressure regime). From the investigation of the mechanical and structural properties, these materials were found to have a large compressibility in the low‐pressure regime, and a small one in the high‐pressure region. In θ ‐(BEDT‐TTF)2CsZn(SCN)4 we observed pressure‐ induced reversible degradation (amorphization) in structure without a solid‐phase reaction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pressure related defect engineering in silicon‐on‐insulator‐like structures produced by either oxygen or nitrogen ion implantation
Authors: Antonova I. V. 
Published: December 2006

AbstractPressure‐related effects in silicon‐on‐insulator‐like structures fabricated in either nitrogen or oxygen implanted silicon during subsequent annealing are analyzed. Among them are the removal of radiation defects from the top silicon layer, some degradation of the buried insulator, pressure dependence of charges at the Si/SiO2 (or Si/SiNx ) interface, formation of the electrically active centers in the top silicon layer and the substrate. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of pressure on the structural properties and electronic band structure of GaSe
Authors: Schwarz U. , Olguin D. , Cantarero A. , Hanfland M. , Syassen K. 
Published: December 2006

AbstractThe structural properties of GaSe have been investigated up to 38 GPa by monochromatic X‐ray diffraction. The onset of the phase transition from the ε ‐GaSe to a disordered NaCl‐type structural motif is observed near 21 GPa. Using the experimentally determined lattice parameters of the layered ε ‐phase as input, constrained ab‐initio total energy calculations were performed in order to optimize the internal structural parameters at different pressures. The results obtained for the nearest‐neighbor Ga–Se distance agree with those derived from recent EXAFS measurements. In addition, information is obtained on the changes of Ga–Ga and Se–Se bond lengths which were not accessible to a direct experimental determination yet. Based on the optimized structural parameters, we report calculations of band gap changes of ε ‐GaSe under pressure. The optical response and electronic band structure of the metallic high‐pressure phase of GaSe are discussed briefly. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural changes in amorphous chalcogenide semiconductors under high pressure: a Raman study
Authors: Boulmetis Y. C. , Stavrou E. , Raptis C. 
Published: December 2006

AbstractThe Raman spectra of binary As–S and ternary Ge–As–S semiconducting chalcogenide glasses have been studied under variable hydrostatic pressure up to 7.0 GPa. Two As–S glasses were investigated, the first at the stoichiometric composition As2S3 (with critical mean coordination number value Z = 2.4) and the other S‐rich, non‐stoichiometric one belonging to the floppy network regime (AsS4, Z = 2.2), while the ternary Ge–As–S glass was on the rigid network side (Ge25As10S65, Z = 2.6). Reversible pressure‐induced effects have been observed in the floppy AsS4 glass manifested by the amorphization of its crystalline sulphur domains. In contrast, the pressure‐induced appearance of homopolar Ge–Ge bonds and the formation of “ethanol‐like” S3Ge–GeS3 units in the rigid ternary Ge25As10S65 glass are irreversible, after pressure relief. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pressure dependence of the optical properties of wurtzite and rock‐salt Zn1–xCoxO thin films
Authors: Sans J. A. , Segura A. , Sánchez‐Royo J. F. , Ferrer‐Roca Ch. , Guillotel E. 
Published: December 2006

AbstractIn this paper we investigate the electronic structure of Zn1–x Cox O by means of optical absorption measurements under pressure. Thin films of Zn1–x Cox O with different Co content (from 1 to 30%) were prepared by pulsed laser deposition on mica substrates. Absorption spectra exhibit three main features that are clearly correlated to the Co content in the films: (i) absorption peaks in the infrared associated to crystal‐field‐split internal transitions in the Co 3d shell, with very small pressure coefficients due to their atomic character; (ii) a broad absorption band below the fundamental edge associated to charge transfer transitions, that exhibit relatively large pressure coefficients, indicating that the Co 3d final states must be strongly hybridized to the conduction band; and (iii) a blue‐shifted fundamental absorption edge associated to band to band transitions with a pressure coefficient close to that of pure ZnO. In the up‐stroke the transition pressure from wurtzite to rock‐salt phase decrease almost linearly as the Co increases, from 9.5 GPa in pure ZnO to about 6.5 GPa for x = 30%. In the down‐stroke pressure we observe a similar behavior, yielding a metastable rock‐salt phase at room pressure, after a pressure cycle up to 15 GPa. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pressure‐induced transition of 2DEG in δ‐doped GaAs to insulating state
Authors: Dizhur Eugene , Voronovsky Anatoly , Kotel'nikov Igor , Dizhur Sergey 
Published: December 2006

AbstractThe tunnelling and lateral conductance of a two‐dimensional electron gas (2DEG) formed in GaAs with a δ‐doped layer were measured simultaneously at hydrostatic pressures at helium temperatures. The resistivity of the δ‐doped layer sharply increases by more than three orders of magnitude at about 2 GPa and its temperature coefficient changes from about –0.04 to about –4 K–1. The tunnelling resistance shows only a slight change of exponential behaviour at about 1.5 GPa while a drastic change of the zero bias anomaly (ZBA) takes place just at the metal–insulator transition (MIT). Such behaviour is interpreted in terms of the pressure dependence of the GaAs band structure and DX‐level position as well as Coulomb gap formation at the MIT. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fourier grid Hamiltonian‐based multidimensional Floquet propagator method for continuous, pulsed, and bichromatic laser field: Application to the multiphoton dissociation dynamics of HCN molecule
Authors: Saha Aparna , Sarkar Pranab , Adhikari S. 
Published: December 2006

AbstractWe present a Fourier grid Hamiltonian‐based multidimensional propagator method for multiphoton dissociation dynamics of triatomic molecule in continuous, pulsed, and bichromatic laser field. The method has been successfully applied to the photodissociation dynamics of HCN molecule, i.e., collinear geometry. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Rainbow Hamilton cycles in random regular graphs
Authors: Janson Svante , Wormald Nicholas 
Published: December 2006

AbstractA rainbow subgraph of an edge‐colored graph has all edges of distinct colors. A random d‐regular graph with d even, and having edges colored randomly with d/2 of each of n colors, has a rainbow Hamilton cycle with probability tending to 1 as n →∞, for fixed d ≥ 8. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007
A simple solution to the k‐core problem
Authors: Janson Svante , Luczak Malwina J. 
Published: December 2006

AbstractWe study the k‐core of a random (multi)graph on n vertices with a given degree sequence. We let n →∞. Then, under some regularity conditions on the degree sequences, we give conditions on the asymptotic shape of the degree sequence that imply that with high probability the k‐core is empty and other conditions that imply that with high probability the k‐core is non‐empty and the sizes of its vertex and edge sets satisfy a law of large numbers; under suitable assumptions these are the only two possibilities. In particular, we recover the result by Pittel, Spencer, and Wormald (J Combinator Theory 67 (1996), 111–151) on the existence and size of a k‐core in G(n,p) and G(n,m), see also Molloy (Random Struct Algor 27 (2005), 124–135) and Cooper (Random Struct Algor 25 (2004), 353–375). Our method is based on the properties of empirical distributions of independent random variables and leads to simple proofs. © 2006 Wiley Periodicals, Inc. Random Struct. Alg.,, 2007
Probabilistic strategies for the partition and plurality problems
Authors: Dvořák Zdeněk , Jelínek Vít , Král' Daniel , Kynčl Jan , Saks Michael 
Published: December 2006

AbstractWe consider a game played by two players, Paul and Carol. Carol fixes a coloring ofnballs with three colors. At each step, Paul chooses a pair of balls and asks Carol whether the balls have the same color. Carol truthfully answers yes or no. In the Plurality problem, Paul wants to find a ball with the most common color. In the Partition problem, Paul wants to partition the balls according to their colors. Paul's goal is to ask Carol the fewest number of questions to reach his goal. We find optimal probabilistic strategies for the Partition problem and the Plurality problem in the considered setting. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007
On the exact interval estimation for the difference in paired areas under the ROC curves
Authors: Li Chi‐Rong , Liao Chen‐Tuo , Liu Jen‐Pei 
Published: December 2006

AbstractAn important measure for comparison of accuracy between two diagnostic procedures is the difference in paired areas under the receiver operating characteristic (ROC) curves. Non‐parametric and maximum likelihood methods have been proposed for interval estimation for the difference in paired areas under ROC curves. However, these two methods are asymptotic procedures and their performance in finite sample sizes has not been thoroughly investigated. We propose to use the concept of generalized pivotal quantities (GPQs) to construct an exact confidence interval for the difference in paired areas under ROC curves. A simulation study is conducted to empirically investigate the probability coverage and expected length of the three methods for various combinations of sample sizes, values of the area under the ROC curve and correlations. Simulation results demonstrate that the exact confidence interval based on the concept of GPQs provides not only sufficient probability coverage but also reasonable expected length. Numerical examples using published data sets illustrate the proposed method. Copyright © 2006 John Wiley & Sons, Ltd.
A 25‐year review of sequential methodology in clinical studies
Authors: Todd Susan 
Published: December 2006

AbstractThis paper explores the theoretical developments and subsequent uptake of sequential methodology in clinical studies in the 25 years sinceStatistics in Medicinewas launched. The review examines the contributions which have been made to all four phases into which clinical trials are traditionally classified and highlights major statistical advancements, together with assessing application of the techniques. The vast majority of work has been in the setting of phase III clinical trials and so emphasis will be placed here. Finally, comments are given indicating how the subject area may develop in the future. Copyright © 2006 John Wiley & Sons, Ltd.
Cardiovascular correlates of disclosing homosexual orientation
Authors: Pérez‐Benítez Carlos I. , O'Brien William H. , Carels Robert A. , Gordon Anne K. , Chiros Christine E. 
Published: December 2006

AbstractMany people conceal their homosexuality. Concealment of homosexual orientation can be experienced as chronic stress and be associated with increased levels of physical symptoms. Research suggests that disclosure may produce a reduction in perceived stress, physical symptoms, and physiological activation. The cardiovascular activations levels of 27 healthy adult gay males were measured during resting baseline, a disclosure task (i.e. participants were instructed to talk about the difficulties associated with concealing one's sexual orientation), and a recovery phase. Several 2 (high/low concealment) × 2 (high/low disclosure) ANOVAs were conducted to determine if there was an interaction between level of concealment and level of disclosure during the recovery period. Results indicated that participants with a high concealment and high disclosure during the study exhibited significantly greater cardiovascular recovery than participants who engaged in a lower level of disclosure. These findings are discussed in light of Pennebaker's research on inhibition and confession. Copyright © 2006 John Wiley & Sons, Ltd.
Daily hassles and depressive symptoms among first year psychology students in France: the role of coping and social support
Authors: Bouteyre Evelyne , Maurel Marion , Bernaud Jean‐Luc 
Published: December 2006

AbstractThe start of university life demands an adaptation period, which can sometimes have an impact on the mental health of students. A total of 233 first year psychology students answered a questionnaire based on a Beck Depression Inventory, Coping Inventory of Stressful Situations, Social Support Questionnaire and Hassles Scale. The results showed 41 per cent of those surveyed suffered of depressive symptoms and that daily hassles encountered during the first year of university could be considered a relevant risk factor for depression. This study makes it possible to observe that not all coping strategies work equally well. Only task‐centered, active coping strategies were effective. With many students having to cope with leaving home, social support also plays a fundamental role. In fact, 70 per cent of those interviewed had left their hometown in order to study. The results of this study suggest that depressive symptoms should be considered a significant problem particularly in first year students. Copyright © 2006 John Wiley & Sons, Ltd.
Obstacles to instructional innovation according to college science and mathematics faculty
Authors: Walczyk Jeffrey J. , Ramsey Linda L. , Zha Peijia 
Published: December 2006

AbstractNumerous studies have documented the infrequent use of learner‐centered instruction in college science and mathematics classrooms and its negative effects on undergraduate learning and motivation. The present research deepened understanding of why. Specifically, an Internet survey was constructed that explored obstacles, supports, and incentives for instructional innovation in the classroom and was sent out to college science and mathematics faculty of Louisiana. Results revealed that colleges generally were perceived to assign little or an indeterminate weight to instruction in personnel decision making. Faculty members generally have little training in pedagogy; but when they do, they are more likely to consult sources of instructional innovation and consider teaching an important part of their professional identities. Data concerning the most common sources of instructional innovation information are presented. Several suggestions are made for institutional reform that if enacted might contribute to systemic improvement in the quality of instruction undergraduates receive. © 2006 Wiley Periodicals, Inc. J Res Sci Teach