bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal oxidative degradation kinetics and thermal properties of poly(ethylene terephthalate) modified with poly(lactic acid)
Authors: Acar Işıl , Pozan Gülin Selda , Özgümüş Saadet 
Published: April 2008

AbstractThe thermal oxidative degradation kinetics of poly(ethylene terephthalate) (PET) copolymers modified with poly(lactic acid) (PLA) were investigated with thermogravimetric analyzer (TGA). The thermal properties of the modified products were also determined by differential scanning calorimeter (DSC) technique. Waste PET (P100) obtained from postconsumer water bottles was modified with a low‐molecular‐weight PLA. The PET/PLA weight ratio was 90/10 (P90) and 50/50 (P50) in the modified samples. The thermal oxidative degradation kinetics of the modified samples was compared with those of PET (P100). The segmented block and/or random copolymer structure of the modified samples formed by a transesterification reaction between the PLA and PET units in solution and the length of the aliphatic and aromatic blocks were found to have a great effect on the degradation behavior. On the basis of the results of the degradation kinetics determined by Kissinger method, the degradation rate of the samples decreased in the order of P50 > P90 > P100, depending on the amount of PLA in the copolymer structure. However, the degradation activation energies (EA) of the samples decreased in the order of P100 > P90 > P50. It was concluded that the degradation rate and mechanism were affected significantly by the incorporation of PLA into the copolymer structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Trends and lacunae for future computer assisted learning (CAL) research: An assessment of the literature in SSCI journals from 1998–2006
Authors: Luor Ted (Tainyi) , Johanson Robert E. , Lu Hsi‐Peng , Wu Ling‐ling 
Published: April 2008

AbstractThis study surveyed 536 CAL publications in 71 SSCI (Social Science Citation Index) journals from 1998 to February 2006 to identify trends and lacunae for future research. The parameters and keywords employed by the authors are first presented, followed by a description of the study's general findings. A comparison is then drawn between CAL and recent depictions of the “blogosphere,” for the majority of the contributors to the field produced only a few articles and authors of individual publications demonstrated a far greater collective influence on the field than the more frequently‐cited authors. Results also revealed that the amount of articles pertaining to the aged, disabled children, and home schooling were significantly lower than those relating to school student's learning. This study offers an interesting snapshot of a field that is apparently on the rise; moreover, it raises some issues to be addressed in further research on CAL‐related topics.
Androgen deprivation falls as orchiectomy rates rise after changes in reimbursement in the U.S. Medicare population
Authors: Weight Christopher J. , Klein Eric A. , Jones J. Stephen 
Published: April 2008

AbstractBACKGROUNDExpenditures related to the use of medical androgen deprivation led in part to the Medicare Modernization Act (MMA) in 2003. This mandated a decline in reimbursement to 80% to 85% of the average wholesale price starting in 2004 followed by a more significant reduction in 2005 to 106% of the average sales price, which effectively reduced the reimbursement by approximately 50% of 2003 values. The authors hypothesized that these changes in reimbursement may affect the way practitioners administer these treatments.METHODSThe publicly available dataset Medicare Part B Extract Summary System was examined from 2001 to 2005 for trends in the number of allowed services and dollar amounts of allowed charges and payments. The reimbursable Medicare codes of J9217 (leuprolide acetate), J9202 (goserelin acetate), J9219 (leuprolide acetate implant), and J3315 (triptorelin pamoate) were examined for medical castration. The code for simple orchiectomy, 54520, was used for surgical castration.RESULTSThe use of medical castration increased from 2001 to 2003, whereas, over the same period, surgical castration decreased. Total allowed charges for medical castration peaked in 2003 at $1.23 billion. After the enactment of the MMA, surgical castration rates increased, and medical castration decreased. Total allowed charges for medical castration in 2005 dropped 65% from the 2003 peak.CONCLUSIONSThe use of medical androgen ablation decreased significantly with the decrease in reimbursement. The administration of either surgical or medical castration in the U.S. Medicare population appears to be tied closely to reimbursement in trend, but not always in magnitude. Cancer 2008. © 2008 American Cancer Society.
Function of Pax1 and Pax9 in the sclerotome of medaka fish
Authors: Mise Takeshi , Iijima Minoru , Inohaya Keiji , Kudo Akira , Wada Hiroshi 
Published: April 2008

AbstractWe examined the expression and functions of Pax1 and Pax9 in a teleost fish, the medaka Oryzias latipes. While Pax1 and Pax9 show distinct expression in the sclerotome in amniotes, we could not detect the differential expression of Pax1 and Pax9 in the developing sclerotome of the medaka. Furthermore, unlike the mouse, in which Pax1 is essential for development of the vertebral body, and where the neural arch is formed independent of either Pax1 or Pax9, our morpholino knockdown experiments revealed that both Pax1 and Pax9 are indispensable for the development of the vertebral body and neural arch. Therefore, we conclude that after gene duplication, Pax1 and Pax9 subfunctionalize their roles in the sclerotome independently in teleosts and amniotes. In Stage‐30 embryo, Pax9 was strongly expressed in the posterior mesoderm, as was also observed for mouse Pax9. Since this expression was not detected for Pax1 in the mouse or fish, this new expression in the posterior mesoderm likely evolved in Pax9 of ancestral vertebrates after gene duplication. Two‐month‐old fish injected with Pax9 morpholino oligonucleotide showed abnormal morphology in the tail hypural skeletal element, which may have been related to this expression. genesis 46:185–192, 2008. © 2008 Wiley‐Liss, Inc.
Use of ERT2‐iCre‐ERT2 for conditional transgenesis
Authors: Jullien Nicolas , Goddard Isabelle , Selmi‐Ruby Samia , Fina Jean‐Luc , Cremer Harold , Herman Jean‐Paul 
Published: April 2008

AbstractWe examined the use of ERT2‐iCre‐ERT2 (Cre2ERT2), a tamoxifen‐regulated form of Cre that has been described to have a background activity lower than that of other tamoxifen‐regulated Cre constructs, for establishing performant conditional deleter mouse lines. Cre2ERT2 was inserted by homologous recombination into the Rosa26 locus. These mice were mated with R26R Cre‐reporter mice. No recombination could be observed in the progenies in the absence of tamoxifen treatment. Tamoxifen treatment at E13‐14 led to a high level, albeit variable, recombination in most of the tissues examined: liver, heart, kidney, brain, lung etc. Treatment of adult animals also induced recombination in these tissues, although at a lower level. Northern blot and qPCR studies suggested that these differences are not linked to significant variations of the level of expression of Cre2ERT2. Thus, Cre2ERT2 appears to be a good alternative to existing modulatable Cre systems, displaying a lack of background activity and a high‐level inducibility in vivo. genesis 46:193–199, 2008. © 2008 Wiley‐Liss, Inc.
Mouse Dach1 and Dach2 are redundantly required for Müllerian duct development
Authors: Davis Richard J. , Harding Mark , Moayedi Yalda , Mardon Graeme 
Published: April 2008

Abstractdachshund/Dach gene family members encode transcriptional cofactors with highly conserved protein interaction domains and are expressed in the developing eyes, brains, and limbs in insects and vertebrates. These observations suggest that the developmental roles of dachshund/Dach in these tissues have been conserved since the divergence of arthropods and chordates. However, while Drosophila dachshund mutants have abnormalities in eye, brain, limbs, mouse Dach1 or Dach2 knockout mutants do not exhibit gross anatomical malformations in these tissues. In addition, Dach1/2 double homozygotes have intact eyes and limbs. Here we show that in Dach1/Dach2 double mutants, female reproductive tract (FRT) development is severely disrupted. This defect is associated with the Müllerian duct (MD) and not the Wolffian duct (WD), which normally differentiate into either the FRT or male reproductive tract (MRT), respectively. Dach1 and Dach2 are expressed in the MD, and in Dach1/2 double mutants, MD expression of Lim1 and Wnt7a is abnormal and MD development is disrupted. In contrast, WD and MRT development are not grossly affected. We propose that Dach1 and Dach2 proteins may redundantly control FRT formation by regulating the expression of target genes required for development of the MD. This vertebrate Dach1/2 function may have been conserved during arthropod evolution, as Drosophila dachshund mutants also exhibit an FRT phenotype. genesis 46:205–213, © 2008 Wiley‐Liss, Inc.
Mechanical and flow characterization of Sponceram® carriers: Evaluation by homogenization theory and experimental validation
Authors: Sanz‐Herrera Jose A. , Kasper Cornelia , van Griensven Martijn , Garcia‐Aznar Jose M. , Ochoa Ignacio , Doblare Manuel 
Published: April 2008

AbstractThe experimental evidence of the dependence of cell proliferation and differentiation in vitro on the mechanical environment aims to the need of characterization of porous scaffolds in terms of mechanical and flow properties. In this sense, the Young's modulus and intrinsic permeability for three types of Sponceram® cell carriers developed for in‐vitro applications are here analyzed. Young's modulus and ultimate compression stress were obtained by performing a two‐plates compression test carried out in a universal microtester machine Instron® for several representative samples of each specimen. A permeability test was also implemented to correlate flow rate and pressure gradient in the linear range. Furthermore, porosity and specific surface were obtained through micro‐CTs of the scaffold microstructure. These experimental data were compared with those obtained numerically by homogenization for several representative volume elements (RVEs) of the scaffolds microstructure. The good agreement found between numerical and experimental results let us consider that the use of numerical techniques is an attractive tool for the analysis of complex scaffold microstructures. Moreover, Sponceram® carriers are shown to have very appropriate properties as bone bioscaffolds which let us recommending further clinical and numerical research on these specific materials. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Molecular parameters of genome instability: Roles of fragile genes at common fragile sites
Authors: Pichiorri Flavia , Ishii Hideshi , Okumura Hiroshi , Trapasso Francesco , Wang Ya , Huebner Kay 
Published: April 2008

AbstractCommon chromosome fragile sites occur at specific sequences within mammalian genomes that exhibit apparent single‐stranded regions in mitotic chromosomes on exposure of cells to replication stress. Recent progress in the characterization of sequences, and more precise mapping of common fragile sites in mammalian and yeast genomes, has led to the exact placement of large common fragile regions straddling the borders of chromosomal G and R bands, with early and late replicating genomic regions, respectively, and could lead to breakthroughs in understanding the function of these evolutionarily conserved but highly recombinogenic chromosome elements. Deficiency of genes involved in DNA damage checkpoint responses, such as ATR, CHK1, HUS1 leads to increased frequency of fragile site instability. Some of these fragile sites, particularly FRA3B, encode genes that are themselves involved in the protection of cells from DNA damage through various mechanisms. Protection of mammalian genomes from accumulation of DNA damage in somatic cells is critical during development, puberty and during the reproductive lifespan, and occurs through mechanisms involving surveillance of the genome for damage, signals to the cell cycle machinery to stop cell cycle progression, signals to repair machinery to repair damage, signals to resume cycling or initiate apoptotic programs, depending on the extent of damage and repair. When genes involved in these processes are altered or deleted, cancer can occur. The tumor suppressor gene, FHIT at the FRA3B locus, and possibly other fragile genes, is a common target of damage and paradoxically encodes a protein with roles in protection from DNA damage. J. Cell. Biochem. 104: 1525–1533, 2008. © 2008 Wiley‐Liss, Inc.
Small applied electric fields guide migration of hippocampal neurons
Authors: Yao Li , Shanley Lynne , McCaig Colin , Zhao Min 
Published: April 2008

AbstractEffectively directed neuron migration is critical for development and repair in the central nervous system (CNS). Endogenous electric fields (EFs) are widespread in developing and regenerating tissues and regulate a variety of cell behaviors including directed cell migration. Electrically‐directed neuronal migration has not been tested previously and we show that an applied EF directs migration of hippocampal neurons toward the cathode at a field strength of 120 mV/mm, close to the physiological range. Reversal of the field polarity reversed the direction of neuron migration. Neuron migration from an explant also was directed by an applied EF. Mechanistically, EF‐guided migration was transduced by activation of the second messenger molecules ROCK (Rho‐associated protein kinase) and PI3 kinase (phosphoinositide‐3 kinase) since their pharmacological inhibition decreased the directedness and speed of neuron migration. This work demonstrates that rat hippocampal neurons respond to applied EFs with directional migration and raises the possibility that EFs may be used as a cue to direct neuronal migration in novel strategies to repair the CNS. J. Cell. Physiol. 216: 527–535, 2008. © 2008 Wiley‐Liss, Inc.
First‐trimester diagnosis of cesarean scar ectopic pregnancy
Authors: Moschos Elysia , Sreenarasimhaiah Sreedevi , Twickler Diane M. 
Published: April 2008

AbstractOnce considered extremely rare, implantation of a pregnancy within the scar of a previous cesarean section is becoming more common. In fact, its incidence is now higher than that of cervical ectopic pregnancies. We identified 5 cases of ectopic pregnancy implanted in a prior cesarean section scar at our institution since 2004. We outline the criteria for the first‐trimester sonographic diagnosis of cesarean scar ectopic pregnancy, including a new sign of lower uterine segment ballooning, which has previously not been reported. Clinicians must have a heightened awareness of this serious and potentially fatal pregnancy complication. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2008.
An identification of stem cell‐resembling gene expression profiles in high‐grade astrocytomas
Authors: Yang Yang , Qiu Yongming , Ren Wenwen , Gong Jialei , Chen Fuxue 
Published: April 2008

AbstractHigh‐grade astrocytomas are among the most intractable types of cancers and are often fatal. Previous studies have suggested that high‐grade astrocytomas may adopt the self‐renewal and migration properties of neural stem cells (NSCs) to proliferate and spread by expressing the stem cell‐specific genes. However, despite a few common molecules being documented, the molecular basis underlying these similarities remains largely unknown. To have a better understanding of the stem cell characteristics of high‐grade astrocytomas, we performed the study to identify the stem cell‐resembling gene expression profile in high‐grade astrocytomas. cDNA microarray analysis was used to detect the differentially expressed genes of isolated human high‐grade astrocytomas versus their peritumoral tissue counterparts, and the identification of stem cell‐resembling genes was approached by comparing the high‐grade astrocytomas‐specific gene expression profile with that of NSCs identified by our previous study and other groups. We identified more than 200 high‐grade astrocytomas‐specific genes in this study, and near 10% genes or gene families of them exhibited similar up or down expression patterns as in NSCs. Further analysis indicated that these genes were actively involved in cell proliferation, adhesion, migration, and metastasis. This study revealed a list of stem cell‐specific genes in high‐grade astrocytomas, which was likely to have critical roles in determining the “stem” characteristics of high‐grade astrocytomas. © 2008 Wiley‐Liss, Inc.
ERp29, an endoplasmic reticulum secretion factor is involved in the growth of breast tumor xenografts
Authors: Mkrtchian Souren , Baryshev Mikhail , Sargsyan Ernest , Chatzistamou Ioulia , Volakaki Aspasia‐Athina , Chaviaras Nick , Pafiti Agatha , Triantafyllou Aggeliki , Kiaris Hippokratis 
Published: April 2008

AbstractCancer cells are committed to an actively secretory state that facilitates communication with their microenvironment. We have addressed the role of ERp29, a novel endoplasmic reticulum secretion factor in mammary carcinogenesis using MCF‐7 human breast cancer cells as a model. Xenografts originating from cells stably transfected with dominant‐negative form of ERp29 were smaller and better differentiated than those derived from cells overexpressing wild‐type ERp29. Similar effects were observed by siRNA‐mediated ERp29 silencing in xenografts. However, unlike xenografts, the modulation of ERp29 in vitro did not affect the rate of cell proliferation. In addition, we have evaluated the expression of ERp29 in the resting and lactating mammary glands of mice as well as in the human primary breast tumors. About 25% of breast cancers and also lactating mammary glands were expressing ERp29 while the resting glands did not. Taken together these data suggest the active involvement of ERp29 in the malignant conversion of mammary epithelial cells. © 2008 Wiley‐Liss, Inc.
A model testing factors that influence physical activity for Taiwanese adults with anxiety
Authors: Ma Wei‐Fen , Lane Hsien‐Yuan , Laffrey Shirley C. 
Published: April 2008

AbstractThe aim of this study was to test a theoretical model of the facilitators and barriers to physical activity for Taiwanese adults with anxiety. Structural equation modeling was used to examine both one‐way direct and indirect influences of 11 personal and cognitive‐emotional factors on physical activity in this population (N = 239). The final version of the model provided a good fit to the data, with nine variables explaining 23.3% of the variance in physical activity. Perceived life stress events, perceived benefits of activity, and perceived self‐efficacy for activity directly influenced physical activity. The results suggest that these variables should be addressed in designing treatment physical activity programs for Taiwanese individuals with anxiety. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:476–489, 2008
Structure and folding of disulfide‐rich miniproteins: Insights from molecular dynamics simulations and MM‐PBSA free energy calculations
Authors: Combelles Cecil , Gracy Jérôme , Heitz Annie , Craik David J. , Chiche Laurent 
Published: April 2008

AbstractThe fold of small disulfide‐rich proteins largely relies on two or more disulfide bridges that are main components of the hydrophobic core. Because of the small size of these proteins and their high cystine content, the cysteine connectivity has been difficult to ascertain in some cases, leading to uncertainties and debates in the literature. Here, we use molecular dynamics simulations and MM‐PBSA free energy calculations to compare similar folds with different disulfide pairings in two disulfide‐rich miniprotein families, namely the knottins and the short‐chain scorpion toxins, for which the connectivity has been discussed. We first show that the MM‐PBSA approach is able to discriminate the correct knotted topology of knottins from the laddered one. Interestingly, a comparison of the free energy components for kalata B1 and MCoTI‐II suggests that cyclotides and squash inhibitors, although sharing the same scaffold, are stabilized through different interactions. Application to short‐chain scorpion toxins suggests that the conventional cysteine pairing found in many homologous toxins is significantly more stable than the unconventional pairing reported for maurotoxin and for spinoxin. This would mean that native maurotoxin and spinoxin are not at the lowest free energy minimum and might result from kinetically rather than thermodynamically driven oxidative folding processes. For both knottins and toxins, the correct or conventional disulfide connectivities provide lower flexibilities and smaller deviations from the initial conformations. Overall, our work suggests that molecular dynamics simulations and the MM‐PBSA approach to estimate free energies are useful tools to analyze and compare disulfide bridge connectivities in miniproteins. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Long‐range analysis of density fitting in extended systems
Authors: Varga Štefan 
Published: April 2008

AbstractDensity fitting scheme is analyzed for the Coulomb problem in extended systems from the correctness of long‐range behavior point of view. We show that for the correct cancellation of divergent long‐range Coulomb terms it is crucial for the density fitting scheme to reproduce the overlap matrix exactly. It is demonstrated that from all possible fitting metric choices the Coulomb metric is the only one which inherently preserves the overlap matrix for infinite systems with translational periodicity. Moreover, we show that by a small additional effort any non‐Coulomb metric fit can be made overlap‐preserving as well. The problem is analyzed for both ordinary and Poisson basis set choices. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Interaction of CO and NO with the spinel CuCr2O4 (100) surface: A DFT study
Authors: Xu Xiang‐Lan , Chen Wen‐Kai , Chen Zhan‐Hong , Li Jun‐Qian , Yi Li  
Published: April 2008

AbstractThe characteristics of CO and NO molecules at Cu2+ and Cr3+ ion sites on the CuCr2O4 (100) surface have been studied by first principles calculations based on spin‐polarized density functional theory (DFT). The calculated results show that adsorption energies for X‐down(C, N) adsorption vary in the order: Cu2+‐CO>Cr3+‐NO≈Cr3+‐CO>Cu2+‐NO. CO molecules are preferentially adsorbed at Cu sites, whereas NO molecules adsorb favorably at Cu2+ and Cr3+ ion sites. The C‐O and N‐O stretching frequencies are red‐shifted upon adsorption. Combining the analysis of frontier molecular orbitals and Mulliken charge, for CO and NO X‐down adsorption systems, the 5σ orbitals donate electrons and the 2π* orbitals obtain back‐donated electrons. Although for NO with O‐down adsorption systems, the NO‐2π* orbitals obtain back‐donated electrons from substrates without 5σ‐donation. Coadsorption calculations show the CO/NO mixture adsorb selectively at the Cu2+ion site but simultaneously at the Cr3+ ion site, respectively. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008