bluuebunny/crossref_metadata_2025_split huggingface dataset:
Freemartin in the amphibian Pleurodeles waltl: Parabiosis between individuals from opposite sex triggers both germ and somatic cells alterations during female gonad development
Authors: Dumond Helene , Maufroid Jean‐Pierre , Ko Chia‐I , Chardard Dominique , Chesnel Amand , Flament Stephane 
Published: November 2007

AbstractWild type embryos of the newt Pleurodeles waltl were used to realize parabiosis, a useful model to study the effect of endogenous circulating hormones on gonad development. The genotypic sex of each parabiont (ZZ male or ZW female) was determined early from the analysis of the sex chromosome borne marker peptidase‐1. In ZZ/ZZ and ZW/ZW associations, gonads develop according to genetic sex. In ZZ/ZW associations, the ZZ gonads differentiate as normal testes while ZW gonads development shows numerous alterations. At the beginning of sex differentiation, these ZW gonads possess a reduced number of germ cells and a reduced expression of steroidogenic factor 1 and P450‐aromatase mRNAs when compared to gonads from ZW/ZW associations. During gonad differentiation, conversely to the control situation, these germ cells do not enter meiosis as corroborated by chromatin status and absence of the meiosis entry marker DMC1; the activity of the estradiol‐producing enzyme P450‐aromatase is as low as in ZZ gonads. At adulthood, no germ cells are observed on histological sections, consistently with the absence of VASA expression. At this stage, the testis‐specific marker DMRT1 is expressed only in ZZ gonads, suggesting that the somatic compartment of the ZW gonad is not masculinized. So, when exposed to ZZ hormones, ZW gonads reach the undifferentiated status but the ovary differentiation does not occur. This gonad is inhibited by a process affecting both somatic and germ cells. Additionally, the ZW gonad inhibition does not occur in the case of an exogenous estradiol treatment of larvae. Mol. Reprod. Dev. 75: 439–449, 2008. © 2007 Wiley‐Liss, Inc.
Factorization for efficient solution of eigenproblems of adjacency and Laplacian matrices for graph products
Authors: Kaveh A. , Rahami H. 
Published: November 2007

AbstractMany structural models can be generated as the graph products of two or three subgraphs known as their generators. The main types of graph products consist of Cartesian, strong Cartesian, direct, and lexicographic products. In this paper, a general method is presented for the factorization of these graph products, such that the eigenvalues of the entire graph are obtained as the union of the eigenvalues of the weighted subgraphs defined here. The adjacency and Laplacian matrices for each graph product are studied separately. For graphs with missing elements (cut‐outs), the eigenvalues are calculated with the additional use of the Rayleigh quotient approach. The main idea stems from the rules recently developed by the authors for block diagonalization of matrices. These products have many applications in computational mechanics, such as ordering, graph partitioning, dynamic analysis, and stability analysis of structures. Some of these applications are addressed in this paper. Copyright © 2007 John Wiley & Sons, Ltd.
Self‐rated health as predictor of medicine use in adolescence
Authors: Holstein Bjørn E. , Hansen Ebba Holme , Andersen Anette , Due Pernille 
Published: November 2007

AbstractPurposeTo examine the association between self‐rated health (SRH) and medicine use for four common complaints: headache, stomach‐ache, difficulties in getting to sleep and nervousness, in a nationally representative sample of adolescents.MethodsThe study population comprised of all students in the fifth, seventh and ninth grade (mean ages 11.6, 13.6 and 15.6 years) in a random sample of schools in Denmark 2002, participation rate 90.6%, n = 4.824. The students reported health problems, medicine use, social and psychosocial conditions in an anonymous and standardized questionnaire. The outcome measure was self‐reported medicine use during the past month and the determinant was SRH measured by one item.ResultsThere was an association between poor/fair SRH and medicine use for headache and stomach‐ache. The associations remained statistically significant even after adjustment for frequency of the complaint for which the medicine was used: OR (95%CI) for medicine use for headache was 1.54 (1.10–2.14) among boys with poor/fair SRH and 1.50 (1.12–2.03) among girls with poor/fair SRH. A similar association was found between poor SRH and medicine use for stomach‐ache for both boys (OR = 3.41 (2.09–5.55)) and girls (OR = 1.90 (1.36–2.67). Further, there was an association between poor/fair SRH and medicine use for difficulties in getting to sleep among girls, OR = 2.66 (1.26–5.63) but not among boys. There was no association between SRH and medicine use for nervousness.ConclusionPoor/fair SRH is associated with medicine use for aches among Danish adolescents. Copyright © 2007 John Wiley & Sons, Ltd.
The effect of structure on the thermoresponsive nature of well‐defined poly(oligo(ethylene oxide) methacrylates) synthesized by ATRP
Authors: Yamamoto Shin‐Ichi , Pietrasik Joanna , Matyjaszewski Krzysztof 
Published: November 2007

AbstractStatistical copolymers of di(ethylene glycol) methyl ether methacrylate (MEO2MA) and tri(ethylene glycol) methyl ether methacrylate (MEO3MA) were synthesized by atom transfer radical polymerization (ATRP) providing copolymers with controlled composition and molecular weights ranging from Mn = 8,300–56,500 with polydispersity indexes (Mw/Mn) between 1.19 and 1.28. The lower critical solution temperature (LCST) of the copolymers increased with the mole fraction of MEO3MA in the copolymer over the range from 26 to 52 °C. The average hydrodynamic diameter, measured by dynamic light scattering, varied with temperature above the LCST. These two monomers were also block copolymerized by ATRP to form polymers with molecular weight of Mn = 30,000 and Mw/Mn from 1.12 to 1.21. The LCST of the block copolymers shifted toward the LCST of the major segment, as compared to the value measured for the statistical copolymers at the same composition. As temperature increased, micelles, consisting of aggregated PMEO2MA cores and PMEO3MA shell, were formed. The micelles aggregated upon further heating to precipitate as larger particles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 194–202, 2008
Experimental Investigation of the Flow Pattern and Wall Pressure Distribution in a Silo with a Double‐Cone Insert
Authors: Wójcik Michał , Härtl Johannes , Ooi Jin Y. , Rotter Michael , Ding Songxiong , Enstad Gisle G. 
Published: November 2007

AbstractThe aim of this paper is to present a recent experimental investigation of the wall pressure distribution and flow pattern observed during the filling and emptying of a full‐scale silo, with and without, inserts. The experiments were carried out with sand, at the Dept. POSTEC in the Tel‐Tek Research Institute in Norway. The results show that the double‐cone insert had a strong influence on the flow and pressures in the silo. A skewed flow often occurred when the insert was installed.
Oxytocin increases 5α‐reductase activity of human prostate epithelial cells, but not stromal cells
Authors: Assinder S.J. 
Published: November 2007

AbstractBACKGROUNDOxytocin is known to modulate 5‐α‐reductase expression and has, therefore, been implicated in the etiology and novel pharmacological treatments of benign prostatic hyperplasia (BPH). These suggestions have been made in the absence of any direct evidence that oxytocin regulates expression or activity of 5‐α‐reductase isoenzymes in the human prostate. This study evaluated the effects of oxytocin on the activity and expression of 5‐α‐reductase isoenzymes I and II of human prostate stromal (PrSC; primary site of BPH development) and epithelial (PrEC) cells.METHODSCell cultures were incubated with oxytocin, or oxytocin plus a specific oxytocin antagonist for 24 hr, and conversion of 3H‐Testosterone to dihydrotestosterone used to estimate total 5‐α‐reductase activity and to determine activity of both type I and type II isoenzymes. Fully quantitative real‐time RT‐PCR determined levels of expression of both isoenzymes following treatments.RESULTSOxytocin significantly increased the total 5‐α‐reductase activity of PrEC but not of PrSC. 5‐α‐Reductase I gene expression and enzyme activity were also increased (P < 0.05) in PrEC by oxytocin. Oxytocin significantly increased type II activity, but not expression, in PrEC. Oxytocin did not significantly affect 5‐α‐reductase activity or expression in PrSC.CONCLUSIONBoth 5‐α‐reductase I and II are expressed in normal human prostate stromal and epithelial cells. Only 5‐α‐reductase isoenzymes of prostate epithelium are modulated by oxytocin. Prostate 68: 115–121, 2008. © 2007 Wiley‐Liss, Inc.
Resolving the controversy on the pH sensitivity of diamond surfaces
Authors: Dankerl M. , Reitinger A. , Stutzmann M. , Garrido J. A. 
Published: November 2007

AbstractThe pH sensitivity of the surface conductivity of H‐terminated diamond has been the subject of great controversy, regarding not only its absolute value but even its sign. In this contribution the effect of the reference electrode on the pH sensitivity is investigated. Thus, the pH response of diamond solution‐gate field effect transistors using Pt and Ag/AgCl reference electrodes has been measured. We demonstrate that the Pt electrode potential is itself pH dependent and over‐ compensates the pH sensitivity of the surface conductivity, which alters significantly the interpretation of the pH sensitivity experiments. If this effect is correctly taken into account the apparent controversy is resolved. The experimental results confirm that the pH sensitivity of the H‐terminated diamond surface conductivity does not follow the prediction of the transfer doping model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fasting increases δ15N‐values in the uric acid of Anolis carolinensis and Uta stansburiana as measured by nondestructive sampling
Authors: Castillo Laura P. , Hatch Kent A. 
Published: November 2007

AbstractPrevious studies suggest that a nutritional/energetic state may be determined from the δ15N‐values of an animal's tissues. It has been hypothesized that if an animal is in a negative nutritional/energetic balance, 15N will be retained by the tissues preferentially and 14N preferentially excreted. Over time, this should cause enrichment of the δ15N‐values of the tissues. Tests of this hypothesis have met with mixed results. To date, these studies have focused on endotherms. Few studies have considered the effects of fasting on the 15N/14N ratios of substrates from ectotherms. We hypothesized that the δ15N‐values of tail tissue and uric acid of fasted lizards would increase over time, while that of the fed lizards would remain the same. We fasted five side‐blotched lizards (Uta stansburiana) and five green anoles (Anolis carolinensis) for 14 days. At the same time we fed six side‐blotched and four green anoles ad libitum. All lizards were given water ad libitum. During this period, we collected uric acid from each lizard daily and tail tissue on the first day of the study and on the last day of the study. We found the the δ15N‐values of uric acid of fasted lizards at the end of the study were 15N‐enriched compared with that of the control lizards in both species, probably due to a shift in amino acid source pools during fasting. However, we found no difference between treatment and controls in the δ15N‐values of the tails. Copyright © 2007 John Wiley & Sons, Ltd.
Detection, management, and follow‐up of pre‐malignant cervical lesions and the role for human papillomavirus
Authors: van Hamont D. , Bekkers R. L. M. , Massuger L. F. A. G. , Melchers W. J. G. 
Published: November 2007

AbstractCervical cytological pathology is common. Prevention of cervical cancer by detecting the disease process at an early and pre‐malignant stage is practised globally either through population‐based screening programmes (PSP) or through non‐organised ones. High‐grade cervical intraepithelial neoplasia (CIN) detected by cervical cytological screening is extensively visualised by colposcopy and successively treated by, for instance, large loop electro‐surgical excision of the transformation zone. Persistent infections with certain high‐risk human papillomavirus (hr‐HPV) genotypes play an essential role in cervical cancer carcinogenesis by mechanisms discussed in this review. HPV assessment, either DNA detection or HPV genotyping, could enhance the current cervical cancer screening programmes. Furthermore, primary prevention of cervical cancer through the introduction of HPV vaccines looks promising although the current vaccines merely protect against two hr‐HPV genotypes, leaving a niche for at least 11 other hr‐HPV's. Cervical screening in the post‐vaccination era cannot be abolished but could be altered, as discussed in this review. Algorithms with the primary objective of hr‐HPV testing followed by subjective cytology assessment in HPV‐positive women could be a solution for both pre‐ and post‐vaccination screening. Copyright © 2007 John Wiley & Sons, Ltd.
Internal layers of parabolic singularly perturbed problems
Authors: Shih S.‐D. 
Published: November 2007

AbstractThe aim of this work is to show, through analyzing some incorrect results in the literature, (i) the internal layer structure is not so predictable for the linear parabolic differential equations with constant coefficients; and (ii) the location of the viscous shock of Burgers' equation in the quarter plane depends on the viscosity, but not in the half plane. Our methods are based on asymptotics of integrals together with special functions to unveil these distinguished features. Contrary to the exponential function as the sole building block of boundary layer functions for differential equations and partial differential equations near the outflow boundary, the class of the complementary error function and its iterated integrals becomes fundamental in this investigation.
Source‐sink dynamics within a plant population: the impact of substrate and herbivory on palm demography
Authors: Berry Eric J. , Gorchov David L. , Endress Bryan A. , Stevens Martin Henry H. 
Published: November 2007

AbstractSite factors have frequently been shown to affect survival, growth, and reproduction in plant populations. The source‐sink concept proposed by Pulliam is one way of integrating this spatial demographic variation into population models. Source‐sink models describe a population where propagules from “source” habitats sustain less productive “sink” areas. We adapted this concept to model the population dynamics of the understory palm Chamaedorea radicalis on two substrates, rock outcrops and forest floor. In our model, sources and sinks correspond to fine‐scale demographic structure within the population, rather than spatially discrete subpopulations as described in the Pulliam model. We constructed a stage‐structured population matrix model that integrates the site‐specific demography of individuals across two habitats types that are linked by migration. We then parameterized this model with field data from C. radicalis. To address whether observed differences in palm demography between rock outcrops and the forest floor were due to natural variation between microsites or due to differences in browsing intensity from free range livestock, we parameterized separate models based on the substrate‐specific demography of protected, non‐browsed palms and of palms exposed to burro browse. Results showed that herbivory reduced survival and fecundity on the forest floor, which in the absence of seed migration resulted in a projected decline of forest floor palms (sinks). However with seed dispersal, palms persisted and total population growth (both substrates) was projected to be positive, indicating that seed dispersal from non‐browsed palms on rock outcrops (sources) was sufficient to sustain C. radicalis on the forest floor.
Self‐reported prevalence, etiology, and characteristics of pain in oncology outpatients
Authors: Valeberg Berit Taraldsen , Rustøen Tone , Bjordal Kristin , Hanestad Berit Rokne , Paul Steven , Miaskowski Christine 
Published: November 2007

AbstractPurpose: To determine the self‐reported prevalence rates for cancer, non‐cancer, and both cancer and non‐cancer pain and to determine if there were differences in demographic, clinical, and pain characteristics among the three pain groups.Methods: Patients were screened in outpatient oncology clinics for the presence of pain and/or analgesic use. Patients who reported pain completed the study questionnaires.Results: A total of 1790 patients were available for screening in the outpatient clinics and 1549 (86.5%) completed the screening questionnaire. Out of them, 332 (21.4%) reported pain or used analgesics. Of the 217 patients who completed the study questionnaires, 53% had only cancer pain (pain due to cancer and/or treatment), 25.3% had non‐cancer pain, and 21.7% had both cancer and non‐cancer pain. No differences were found, among the three pain groups, in pain intensity or pain duration. However patients in the cancer and non‐cancer pain group had higher pain interference scores, higher severity scores for various pain descriptors, and a higher number of pain locations.Conclusions: These findings suggest that outpatients with a combination of cancer and non‐cancer pain may be at greater risk for under‐treatment of pain. Oncology clinicians and primary care providers need to perform a comprehensive pain assessment of all oncology patients in order to be able to formulate an effective pain management plan.
Uniformization for sampling realizations of Markov processes: applications to Bayesian implementations of codon substitution models
Authors: Rodrigue Nicolas , Philippe Hervé , Lartillot Nicolas 
Published: November 2007

Abstract
Motivation: Mapping character state changes over phylogenetic trees is central to the study of evolution. However, current probabilistic methods for generating such mappings are ill-suited to certain types of evolutionary models, in particular, the widely used models of codon substitution.
Results: We describe a general method, based on a uniformization technique, which can be utilized to generate realizations of a Markovian substitution process conditional on an alignment of character states and a given tree topology. The method is applicable under a wide range of evolutionary models, and to illustrate its usefulness in practice, we embed it within a data augmentation-based Markov chain Monte Carlo sampler, for approximating posterior distributions under previously proposed codon substitution models. The sampler is found to be more efficient than the conventional pruning-based sampler with the decorrelation times between draws from the posterior reduced by a factor of 20 or more.
Contact: nicolas.rodrigue@umontreal.ca
Computational design of the Fyn SH3 domain with increased stability through optimization of surface charge–charge interactions
Authors: Schweiker Katrina L. , Zarrine‐Afsar Arash , Davidson Alan R. , Makhatadze George I. 
Published: November 2007

AbstractComputational design of surface charge–charge interactions has been demonstrated to be an effective way to increase both the thermostability and the stability of proteins. To test the robustness of this approach for proteins with predominantly β‐sheet secondary structure, the chicken isoform of the Fyn SH3 domain was used as a model system. Computational analysis of the optimal distribution of surface charges showed that the increase in favorable energy per substitution begins to level off at five substitutions; hence, the designed Fyn sequence contained four charge reversals at existing charged positions and one introduction of a new charge. Three additional variants were also constructed to explore stepwise contributions of these substitutions to Fyn stability. The thermodynamic stabilities of the variants were experimentally characterized using differential scanning calorimetry and far‐UV circular dichroism spectroscopy and are in very good agreement with theoretical predictions from the model. The designed sequence was found to have increased the melting temperature, ΔTm = 12.3 ± 0.2°C, and stability, ΔΔG(25°C) = 7.1 ± 2.2 kJ/mol, relative to the wild‐type protein. The experimental data suggest that a significant increase in stability can be achieved through a very small number of amino acid substitutions. Consistent with a number of recent studies, the presented results clearly argue for a seminal role of surface charge–charge interactions in determining protein stability and suggest that the optimization of surface interactions can be an attractive strategy to complement algorithms optimizing interactions in the protein core to further enhance protein stability.
Self‐administration of drugs in animals and humans as a model and an investigative tool
Authors: Panlilio Leigh V. , Goldberg Steven R. 
Published: November 2007

ABSTRACTAim  To review briefly the methods, assumptions, models, accomplishments, drawbacks and future directions of research using drug self‐administration in animals and humans.Background  The use of drug self‐administration to study addiction is based on the assumption that drugs reinforce the behavior that results in their delivery. A wide range of drug self‐administration techniques have been developed to model specific aspects of addiction. These techniques are highly amenable to being combined with a wide variety of neuroscience techniques.Conclusions  The identification of drug use as behavior that is reinforced by drugs has contributed greatly to the understanding and treatment of addiction. As part of a program of pre‐clinical research that also involves screening with a variety of simpler behavioral techniques, drug self‐administration procedures can provide an important last step in testing potential treatments for addiction. There is currently a concerted effort to develop self‐administration procedures that model the extreme nature of the behavior engendered by addiction. As advances continue to be made in neuroscience techniques, self‐administration should continue to provide a means of applying these techniques within a sophisticated and valid model of human drug addiction.
Childbirth, abortion and subsequent substance use in young women: a population‐based longitudinal study
Authors: Pedersen Willy 
Published: November 2007

ABSTRACTAims  To investigate the possible linkages between deliveries, abortions and subsequent nicotine dependence, alcohol problems and use of cannabis and other illegal drugs from the ages of 15–27 years.Methods  Data were gathered as part of the Young in Norway Longitudinal Study, an 11‐year follow‐up of a representative sample of Norwegian adolescents and young adults.Design, setting and participants  Information was obtained on (i) the history of childbirths and induced abortions for the participants between the ages of 15–27 years; (ii) measures of nicotine dependence, alcohol problems and use of cannabis and other illegal drugs; and (iii) socio‐demographic, family and individual confounding factors.Results  Those who had had an abortion had elevated rates of substance use and problems. Those who gave birth to a child had reduced rates of alcohol problems and cannabis use. These associations persisted after control for confounders. However, those women who still lived with the father of the aborted fetus were not at increased risk.Conclusions  Abortion in women may, under some circumstances, be associated with increased risk of nicotine dependence, alcohol problems and use of cannabis and other illegal drugs. The birth of a child may reduce the use of some substances.