bluuebunny/crossref_metadata_2025_split huggingface dataset:
S. epidermidis biofilm formation: Effects of biomaterial surface chemistry and serum proteins
Authors: Patel Jasmine D. , Ebert Michael , Ward Robert , Anderson James M. 
Published: December 2006

AbstractMost infections due to implanted cardiovascular biomaterials are initiated by bacterial adhesion of Staphylococcus epidermidis, followed by colonization and biofilm formation on the surface of the implant. This study examined the role of serum proteins and material surface chemistry in the formation of S. epidermidis biofilm on polyurethanes (Elasthane 80A, hydrophobic) modified with polyethylene oxide (Elasthane 80A‐6PEO, hydrophilic) and fluorocarbon (Elasthane 80A‐6F, hydrophobic). Initial adhesion, aggregation, biofilm thickness, viability, and slime formation of S. epidermidis strain, RP62A in phosphate buffered saline (PBS), tryptic soy broth (TBS), and 20% pooled human serum was quantified. In the presence of adsorbed serum proteins, initial bacterial adhesion was suppressed significantly to <2% relative to adhesion in TSB or PBS. However, adhesion, aggregation, and proliferation increased dramatically in the 12–24 h period on Elasthane 80A and Elasthane 80A‐6F, which resulted in an extensive network of biofilm. A contrasting trend was observed on the hydrophilic Elasthane 80A‐6PEO surface, with minimal bacterial adhesion, which decreased steadily over 24 h. In the presence of serum proteins, an increasingly thick (∼20 μm) biofilm formed on the hydrophobic surfaces over 48 h whereas the formation of a mature biofilm on the hydrophilic surface was impeded with few viable bacteria present over 48 h. Furthermore, slime was detected during the initial phase of bacterial adhesion at 2 h and increased over time with the formation of biofilm. These results have shown that while initial S. epidermidis adhesion is suppressed in the presence of adsorbed proteins, inter‐bacterial adhesion possibly aided by slime production leads to the formation of a robust mature biofilm. Also, biomaterial surface chemistry affected biofilm formation and, most notably, polyethylene oxide significantly inhibited S. epidermidis biofilm formation over 48 h in vitro. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
The commonality of plasticity underlying multipotent tumor cells and embryonic stem cells
Authors: Postovit Lynne‐Marie , Costa Fabricio F. , Bischof Jared M. , Seftor Elisabeth A. , Wen Bo , Seftor Richard E. B. , Feinberg Andrew P. , Soares Marcelo Bento , Hendrix Mary J. C. 
Published: December 2006

AbstractAggressive cancer cells and pluripotent stem cells converge in their capacity for self‐renewal, proliferation and plasticity. Recent studies have capitalized on these similarities by demonstrating that tumors arise from specific cancer stem cell populations that, in a manner reminiscent of normal stem cells, are able to both self‐renew and give rise to a heterogeneous tumor population. This stem cell like function of aggressive cancer cells is likely attributable to the ectopic expression of embryonic factors such as Nodal and Cancer Testis Specific Antigens (CTAs), which maintain a functional plasticity by promoting pluripotency and immortality. During development, the expression of these embryonic factors is tightly regulated by a dynamic array of mediators, including the spatial and temporal expression of inhibitors such as Lefty, and the epigenetic modulation of the genome. In aggressive cancer cells, particularly melanoma, this balance of regulatory mediators is disrupted, leading to the aberrant expression of pluripotency‐associated genes. By exposing aggressive cancer cells to embryonic microenvironments, this balance of regulatory mediators is restored, thereby reprogramming tumor cells to a more benign phenotype. These stem cell‐derived mediators, as well as the genes they regulate, provide therapeutic targets designed to specifically differentiate and eradicate aggressive cancers. J. Cell. Biochem. 101: 908–917, 2007. © 2006 Wiley‐Liss, Inc.
Diploid sperm produced by artificially sex‐reversed Clone loaches
Authors: Yoshikawa Hiroyuki , Morishima Kagayaki , Kusuda Satoshi , Yamaha Etsuro , Arai Katsutoshi 
Published: December 2006

AbstractClone loaches reproduce unisexually in a wild population of Hokkaido Island, Japan. These clone loaches produce genetically identical unreduced eggs which develop to diploid individuals without any genetic contribution of sperm donors. In the present study, sex reversal of clone loaches was attempted and the reproductive potential of resultant clone males was examined. Clone loaches administered 0.5 ppm of 17‐α methyltestosterone (MT) for 30 days from 1 month after hatching differentiated into physiological males. These sex‐reversed clone males produced fertile spermatozoa with a diploid DNA content. Diploid spermatozoa had significantly larger heads than normal haploid sperm, but had a normal shape showing a head, mid‐piece, and tail. The motility of diploid spermatozoa was low after ambient water was added. Concentration of diploid spermatozoa per unit of sperm was lower than that of control haploid spermatozoa. Microsatellite genotyping revealed that triploid progeny from the cross between a normal diploid female and a sex‐reversed clone male had two alleles specific to the diploid clone male and one allele of the mother loach. These results indicated that the sex‐reversed clone males produced fertile diploid spermatozoa genetically identical to the clone lineage. J. Exp. Zool. 307A:75–83, 2007. © 2006 Wiley‐Liss, Inc.
Antler regeneration: a dependent process of stem tissue primed via interaction with its enveloping skin
Authors: Li Chunyi , Yang Fuhe , Li Guangyu , Gao Xiuhua , Xing Xiumei , Wei Haijun , Deng Xuming , Clark Dawn E. 
Published: December 2006

AbstractDeer antlers are unique mammalian appendages in that each year they are cast and fully regenerate from permanent bony protuberances, called pedicles. In a previous study, we found that there is a difference in the degree of association between pedicle bone and its enveloping skin: tight at the distal third and loose at the proximal two thirds of a pedicle stump. The distal part has been termed the “potentiated” region, and the proximal part the “dormant” region. In the present study, pedicle stumps were artificially created in yearling sika deer by cutting off the tissue distal to either the potentiated or the dormant region. A piece of impermeable membrane was then inserted into the space between the bone and the skin of each treated pedicle stump, while the control pedicles had the same surgery without membrane insertion. The results showed that the inserted membrane blocked pedicle skin participation in the process of antler regeneration. All three potentiated bony pedicle stumps regenerated skin‐less antlers; whereas, one of the three dormant bony pedicle stumps failed to regenerate any antler tissue. The other two dormant stumps eventually regenerated normal antlers; however, this only occurred after loss of the inserted membrane. No antler tissue regenerated from the dormant stumps while the inserted membrane remained in place (up to 55 days). All control pedicle stumps regenerated normal antlers. Therefore, we conclude that it is the pedicle bone, but not pedicle skin, that gives rise to regenerating antlers, and that pedicle bone can acquire the potential to regenerate an antler only when it is primed via interaction with its enveloping skin. J. Exp. Zool. 307A:95–105, 2007. © 2006 Wiley‐Liss, Inc.
A new strategy based on recombinant viruses as a tool for assessing drug susceptibility of human immunodeficiency virus type 1
Authors: Garcia‐Perez J. , Sanchez‐Palomino S. , Perez‐Olmeda M. , Fernandez B. , Alcami J. 
Published: December 2006

AbstractThe emergence of drug‐resistant variants during antiretroviral therapy is a serious obstacle to sustained suppression of the human immunodeficiency virus type 1 (HIV‐1). For that reason, resistance assays are essential to guide clinicians in the selection of optimal treatment regimens. Genotypic assays are less expensive and results are available faster than phenotypic assays. However, in heavily experienced patients with multiple treatment failures interpretation of complex mutation patterns remains difficult, and in these cases phenotypic assays are recommended. This report describes a novel recombinant virus assay where protease (PR) and reverse transcriptase (RT) sequences derived from the plasma isolated from patients are introduced into the back‐bone of an HIV molecular clone that expresses Renilla luciferase protein in the place of nef gene. All drug resistance profiles analyzed correlate with previously reported data and showed high reproducibility. This assay, in addition to a fast (completed in 10 days), precise, reproducible and automated method, presents several advantages as compared to other phenotypic assays. The system described below allows the generation of recombinant viruses with multiples cycles of replication carrying a reporter gene in their genomes. These features increase the sensitivity of the test, an important aspect to be considered in the evaluation of less fit viral isolates. In conclusion, the assay permits the quantitation of the level of resistance of clinical HIV‐1 isolates to PR and RT inhibitors. J. Med. Virol. 79:127–137, 2007. © 2006 Wiley‐Liss, Inc.
Molecular characterization of human T‐cell lymphotropic virus type 2 (HTLV‐II) from people living in urban areas of Sao Paulo city: Evidence of multiple subtypes circulation
Authors: Novoa Patricia , Penalva de Oliveira Augusto César , Posada Vergara Maria Paulina , da Silva Duarte Alberto José , Casseb Jorge 
Published: December 2006

AbstractBackgroundIn Brazil, human T‐cell lymphotropic virus type I and type II (HTLV‐I and HTLV‐II) are co‐circulating and possess approximately 65% homology, which results in high cross‐reactivity in serological tests. Based on the detection of EIA and Western blot (WB) tests, HTLV serodiagnosis yields indeterminate results in high‐risk population, with the true determination of HTLV‐II prevalence requiring a combined serological and molecular analysis. Molecular analysis of HTLV‐II isolates has shown the existence of four distinct subtypes: IIa, IIb, IIc, and IId. The aim of this study was to evaluate the routine EIA and WB used in Sao Paulo city, as well as molecular methods for confirmation of infection and HTLV‐II subtype distribution. Results: Two hundred ninety‐three individuals, who were enrolled in the HTLV out‐clinic in Sao Paulo city, Brazil, between July 1997 and May 2003, were tested by EIAs, and positive sera 232 (79%) reactive by one of the tests. When these sera were tested by WB revealed 134 were HTLV‐I, 28 HTLV‐II, 4 HTLV‐I/II, and 48 were indeterminate. Polymerase chain reaction (PCR) on the indeterminate group showed that 20 (42%) were HTLV‐II and 28 were negative. From a total of 48 HTLV‐II subjects with DNA available, restriction fragment length polymorphism (RFLP) of the env region revealed 47 HTLV‐IIa and 1 HTLV‐IIb. The phylogenetic analysis was performed on 23 samples, which identified 19 as subtype a, Brazilian subcluster, and 4 as subtype b. This is the first time HTLV‐II subtype b has been described in Brazil. However, further studies, such as a complete nucleotide DNA sequencing, need to be done to confirm these findings. J. Med. Virol. 79:182–187, 2007. © 2006 Wiley‐Liss, Inc.
Cowpea cooking characteristics as affected by micronisation temperature: a study of the physicochemical and functional properties of starch
Authors: Mwangwela Agnes M , Waniska Ralph D , McDonough Cassandra , Minnaar Amanda 
Published: December 2006

AbstractBechuana white cowpeas were micronised to three temperatures (130, 153 and 170 °C). Cooking properties of the cowpea seeds and the role of starch‐related properties were studied. In all cases, micronisation significantly reduced the cooking time and thus the time required for the cowpea seeds to attain a suitably soft texture. This was attributed in part to the significant improvement in rate of water absorption during cooking and starch pre‐gelatinisation, as evidenced by loss of birefringence and increased susceptibility of the cowpea starch to α‐amylase digestion. However, micronisation to 170 °C resulted in a severe deterioration in pasting properties of the cowpea flour, possibly due to starch depolymerisation and/or amylose‐associated crosslinking. Owing to these changes, cowpea seeds micronised to 170 °C required a longer cooking time than the other two micronised samples. Flour prepared from cowpea seeds micronised to 170 °C may have limited starch functionality. Copyright © 2006 Society of Chemical Industry
Outbound supply chain network design with mode selection and lead time considerations
Authors: Eskigun Erdem , Uzsoy Reha , Preckel Paul V. , Beaujon George , Krishnan Subramanian , Tew Jeffrey D. 
Published: December 2006

AbstractWe present a large‐scale network design model for the outbound supply chain of an automotive company that considers transportation mode selection (road vs. rail) and explicitly models the relationship between lead times and the volume of flow through the nodes of the network. We formulate the problem as a nonlinear zero‐one integer program, reformulate it to obtain a linear integer model, and develop a Lagrangian heuristic for its solution that gives near‐optimal results in reasonable time. We also present scenario analyses that examine the behavior of the supply chain under different parameter settings and the performance of the solution procedures under different experimental conditions. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Protein labeling by iTRAQ: A new tool for quantitative mass spectrometry in proteome research
Authors: Wiese Sebastian , Reidegeld Kai A. , Meyer Helmut E. , Warscheid Bettina 
Published: December 2006

AbstractA novel, MS‐based approach for the relative quantification of proteins, relying on the derivatization of primary amino groups in intact proteins using isobaric tag for relative and absolute quantitation (iTRAQ) is presented. Due to the isobaric mass design of the iTRAQ reagents, differentially labeled proteins do not differ in mass; accordingly, their corresponding proteolytic peptides appear as single peaks in MS scans. Because quantitative information is provided by isotope‐encoded reporter ions that can only be observed in MS/MS spectra, we analyzed the fragmentation behavior of ESI and MALDI ions of peptides generated from iTRAQ‐labeled proteins using a TOF/TOF and/or a QTOF instrument. We observed efficient liberation of reporter ions for singly protonated peptides at low‐energy collision conditions. In contrast, increased collision energies were required to liberate the iTRAQ label from lysine side chains of doubly charged peptides and, thus, to observe reporter ions suitable for relative quantification of proteins with high accuracy. We then developed a quantitative strategy that comprises labeling of intact proteins by iTRAQ followed by gel electrophoresis and peptide MS/MS analyses. As proof of principle, mixtures of five different proteins in various concentration ratios were quantified, demonstrating the general applicability of the approach presented here to quantitative MS‐based proteomics.
Magneto‐optical investigation of high temperature ion implanted MnxGe1–x alloy: evidence for multiple contributions to the magnetic response
Authors: Verna A. , D'Orazio F. , Ottaviano L. , Passacantando M. , Lucari F. , Impellizzeri G. , Priolo F. 
Published: December 2006

AbstractWe have studied the magnetic properties of a 240 °C ion implanted MnGe alloy (100 keV, 2 × 1016 ions/cm2) by means of magneto‐optical Kerr effect (MOKE) hysteresis loops taken at different wavelengths in the visible/near‐infrared range and at different temperatures (12–180 K). The details of the MOKE response indicates that the magnetic properties of the sample are due to the contribution of multiple magnetic phases. These can be ascribed to the known coexistence of Mn atoms diluted in the mono‐crystalline Ge matrix and of amorphous semiconductive Mn‐rich precipitates embedded in it. Our results demonstrate that both phases contribute to the ferromagnetic ordering in Mnx Ge1–x magnetic semiconductors. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theory of ferromagnetic semiconductors
Authors: Katayama‐Yoshida H. , Sato K. , Fukushima T. , Toyoda M. , Kizaki H. , Dinh V. A. , Dederichs P. H. 
Published: December 2006

AbstractBased upon ab initio electronic structure calculations by the Korringa–Kohn–Rostoker coherent‐potential approximation (KKR‐CPA) method within the local‐density approximation (LDA), we propose a unified physical picture of magnetism and an accurate calculation method of Curie temperature (T C) in dilute magnetic semiconductors (DMSs) in II–VI and III–V compound semiconductors. We also propose the unified physical picture of magnetism in the DMS, where ferromagnetic Zener's double‐exchange mechanism (or Zener's p–d exchange mechanism) caused by the partially occupied impurity band and anti‐ferromagnetic super‐exchange mechanism (or ferromagnetic super‐exchange mechanism) is competing to determine the magnetic states in the DMS. We propose that the three‐dimensional 3D Dairiseki‐phase and one‐dimensional 1D Konbu‐phase caused by spinodal nano‐decomposition are responsible for high‐T C phase in the inhomogeneous system. We propose the new methodology to go beyond LDA to describe the highly correlated electron system by taking into account the self‐interaction correction (SIC) to the LDA. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extended Drude model analysis of noble metals
Authors: Youn S. J. , Rho T. H. , Min B. I. , Kim Kwang S. 
Published: December 2006

AbstractWe have applied the extended Drude model (EDM) to noble metals of Cu, Ag, and Au. Drude parameters are obtained self‐consistently without using the sum rule or any approximation. The core polarization contribution ε∞ is shown to be large due to shallow d‐orbitals. The frequency dependent mass enhancement factor λ (ω) and the scattering rate 1/τ (ω) are obtained. The Drude region can be identified when 1/τ (ω) deviates from the Fermi liquid behavior due to interband transitions. The onset frequency for the interband transition is found to be lower than the frequency value at the minimum of the imaginary part of the dielectric constant. The validity of the approximation of ωτ ≫ 1, which is commonly employed in analyzing optical data, has been checked based on the EDM for noble metals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cr‐site preference of BaFe12–xCrxO19 hexaferrite ceramics monitored by Mössbauer spectroscopy
Authors: Ounnunkad Suriya , Phanichphant Sukon , Winotai Pongtip , Tang I‐Ming 
Published: December 2006

AbstractSite preference of Cr in the M‐type barium ferrite ceramics was monitored by powder X‐ray diffraction (XRD), magnetization measurements and Mössbauer spectroscopy. The calcined BaFe12–x Crx O19 powders (x = 0.0–0.8) obtained by the sol gel method were die‐pressed into pellets and then sintered at 1300 °C in a oxygen atmosphere for 12 hrs. All the phases of the ceramics were of the pure magnetoplumbite structure. The saturation magnetization (Ms) is found to be a function of Cr ion content. The MS of the ceramics decreases due to the dilution of the magnetic interaction with increasing Cr concentration. The coercivity (Hc) of the ceramics increases due to finer grain observed by scanning electron microscopy (SEM). Fitted Mössbauer spectra show that Cr ions preferentially occupy into the 2a, 12k and 4f2 Fe crystallographic sites. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrostatic pressure effects on the Γ–X conduction band mixing and the binding energy of a donor impurity in GaAs–Ga1–xAlxAs quantum wells
Authors: Duque C. A. , López S. Y. , Mora‐Ramos M. E. 
Published: December 2006

AbstractMixing between Γ and X valleys of the conduction band in GaAs–Ga1–x Alx As quantum wells is investigated taken into account the effect of applied hydrostatic pressure. This effect is introduced via the pressure‐dependent values of the corresponding energy gaps and the main band parameters. The mixing is considered along the lines of a phenomenological model. Variation of the confined ground state in the well as a function of the pressure is reported. The dependencies of the variationally calculated binding energy of a donor impurity with the hydrostatic pressure and well width are also presented. It is shown that the inclusion of the Γ–X mixing explains the non‐linear behavior in the photoluminescence peak of confined exciton states that has been observed for pressures above 20 kbar. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new set of electronegativity scale for trivalent lanthanides
Authors: Li Keyan , Xue Dongfeng 
Published: December 2006

AbstractA new set of electronegativity (EN) scale for all trivalent lanthanides (Ln) is proposed on the basis of effective ionic potential, from which the electron‐attracting power of trivalent Ln can be well differentiated. This new scale can be used to qualitatively explain the valence stability and valence change of some typical trivalent Ln. Furthermore, the good linear relationships of the charge‐transfer energy of Ln3+ and the first dehydroxylation temperature in the agardite to the current EN scale of Ln3+ show us the further reasonableness of our new EN scale. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural properties of simulated liquid and amorphous TiO2
Authors: Van Hoang Vo 
Published: December 2006

AbstractStructural properties of liquid and amorphous TiO2 have been studied in a model containing 3000 particles under periodic boundary conditions with the pairwise interatomic potentials proposed by Matsui and Akaogi. Models have been obtained by cooling from the melt via molecular dynamics (MD) simulation. Structural properties of an amorphous model obtained at 350 K have been analyzed in details through the partial radial distribution functions (PRDFs), coordination number distributions, bond‐angle distributions and interatomic distances. Calculations show that calculated data agree well with the experimental ones. The evolution of structure upon cooling from the melt was observed and discussed. Calculations show that amorphous TiO2 has a distorted octahedral network structure with the mean coordination number ZTi–O ≈ 6.0 and ZO–Ti ≈ 3.0. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Autonomous catheter insertion system using magnetic motion capture sensor for endovascular surgery
Authors: Tercero C. , Ikeda S. , Uchiyama T. , Fukuda T. , Arai F. , Okada Y. , Ono Y. , Hattori R. , Yamamoto T. , Negoro M. , Takahashi I. 
Published: December 2006

AbstractBackgroundIn order to reduce fluoroscope usage in endovascular surgery, there is a need to develop autonomous catheter insertion systems.MethodsWe propose a system for tracking the position and speed of a catheter using a magnetic motion capture sensor to provide feedback to a catheter‐driving mechanism, to perform autonomous catheter insertion in major vasculature. Catheter insertion speed control and path reconstruction experiments were performed with the system inside a silicone model of major vasculature to simulate surgery.ResultsThe system controlled the catheter for speeds of 6.14 mm/s and reproduced a two‐dimensional path inside the silicone blood vessel phantom with less than 7 mm of error.ConclusionsWe found that error in speed control rises as a result of friction between the catheter and the model wall. Path reconstruction error depends on the model's cross‐sectional diameter, the properties of the catheter insertion mechanism, the magnetic sensor and the system guidance technique. Copyright © 2006 John Wiley & Sons, Ltd.