bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nullbruchlinie der Dauerfestigkeit
Authors: Köhler J. 
Published: September 2008

AbstractMit ca. 45 Proben werden Dauerschwingversuche durchgeführt. In der anschließenden Auswertung wird die Nullbruchlinie mit der Bruchwahrscheinlichkeit 1ppm ermittelt.Die Nullbruchlinie ist die gemeinsame Wöhlerlinie für ungekerbte und gekerbte Bauteile. Sie gilt für große und kleine Bauteile aus dem gleichen Werkstoff. Man muß den statistischen Größeneinfluß nicht berücksichtigen.
Experimental studies on selective laser melting of metallic parts
Authors: Meier H. , Haberland Ch. 
Published: September 2008

AbstractLaser assisted generative production techniques like Selective Laser Melting (SLM) are novel but complex near net shape fabrication methods. The present paper describes properties of metallic specimens generated by SLM. Therefore various process parameters were observed to evaluate their influence on certain attributes of parts fabricated by Selective Laser Melting. In addition, approaches for an improvement of density, surface quality and mechanical properties are given.
Hybrides Walzen am Beispiel von Titan‐Aluminium‐Verbunden
Authors: Bach Fr.‐ W. , Bormann D. , Rodmann M. , Haverkamp H. 
Published: September 2008

AbstractDreilagige Titan‐Aluminiumverbunde aus den Titanlegierungen TiAl6V4 (ASTM grade 5) und Ti 99,8 (ASTM grade 1) sowie den Aluminiumlegerungen Al Mg Si0,5 (EN‐AW 6060) und AlCuMg1 (EN‐AW 2017) werden durch Warmwalzen hergestellt und das Umformverhalten unter unterschiedlichen Umformparametern betrachtet. Schwerpunkt ist die Untersuchung der Unterschiede zwischen schrittweiser und kontinuierlicher Erhöhung des Umformgrades. Getestet werden Umformgrade von 20…60 % bei Temperaturen von 400…500 °C. Anschließend wird die Kontaktzone der hergestellten Verbunde metallographisch untersucht und die Haftfestigkeit der Schichten mechanisch geprüft. Zur qualitativen Bestimmung der Haftfestigkeit des Verbundes werden Torsionsversuche vorgestellt. Der Beginn des Haftungsaufbaus stellt sich bereits bei Umformgraden von 35 % und Temperaturen von 350 °C im Walzspalt ein.
Wirkmedienbasierte Herstellung hybrider Metall‐Kunststoff‐Verbundbauteile mit Kunststoffschmelzen als Druckmedium
Authors: Hussain M. M. , Rauscher B. , Tekkaya A. E. 
Published: September 2008

AbstractIm Rahmen der durchgeführten Arbeiten wurde eine innovative Verfahrensalternative zur Herstellung hybrider Metall‐Kunststoffbauteile untersucht. Gegenstand ist die Kombination des Kunststoff‐Spritzgießprozesses mit Blech‐ bzw. Profilumformtechnologien. Im Zuge der Umformung von Dom‐ und Napfgeometrien aus Aluminium‐ und Stahlwerkstoffen wurden grundlegende Prozessparameter wie Spritzgießdruck, Volumenstrom gemessen und die hergestellten Bauteile hinsichtlich ihrer Geometrie und Formänderungsverteilung untersucht.
Dynamic analysis of the micromilling process – influence of tool vibrations on the quality of microstructures
Authors: Baschin A. , Kahnis P. , Biermann D. 
Published: September 2008

AbstractMicromilling is a suitable technique for the manufacturing of microstructured parts. The downscaling of the milling process leads to problems, which are caused by the low stability of microtools and their manufacturing. Tool vibrations and runout occur, resulting in poor surface qualities and undesirable surface location errors. The presented results of the experimental analysis include a stability diagram for the spindle speed range of n = 60,000–120,000 rpm and tool vibrations measured in the xy‐plane. Micrographs illustrate the influence of tool vibrations on the quality of the generated surface structures. In addition, the dynamic runout is characterized and its effects are discussed.
Diffusionslöten von Aluminium mittels PVD applizierter Lotzusatzwerkstoffe
Authors: Tillmann W. , Wojarski L. , Liu C. , Osmanda A. M. 
Published: September 2008

AbstractDas Diffusionslöten mit Lotbestandteilen beschichteter Aluminium und Aluminiumlegierungen ermöglicht eine flussmittelfreie Herstellung von Lötverbindungen hoher Festigkeit bei moderaten Löttemperaturen. Die über den vorangegangenen Arc‐PVD‐Prozess auf der Oberfläche abgeschiedenenen Lotbestandteile lassen infolge der Diffusionvorgänge im anschließenden Diffusionslötprozess lokal eine Flüssigphase (transient liquid phase) entstehen. Diese bildet sich aus dem Schichtmaterial und dem Grundwerkstoff und erstarrt isotherm infolge der voranschreitenden Diffusionsvorgänge, so dass Verbunde mit einer höheren Wiederaufschmelztemperatur als der Löttemperatur realisiert werden können. In dieser Arbeit wurden die beiden Lotsysteme Al‐Cu und Al‐Cu‐Si für die Anwendung innerhalb dieses hybriden Fügeprozesses evaluiert. Cu bzw. Al‐Cu‐Si sind dabei über den Arc‐PVD‐Prozess auf die Grundwerkstoffoberfläche abgeschieden worden. Als Grundwerkstoffe kamen reines Aluminium und EN‐AW6060 zur Anwendung. Metallographische und rasterelektronenmikroskopische Untersuchungen haben ergeben, dass die Fügezone nach Abschluss des Diffusionslötprozesses eine dem Grundwerkstoff ähnelnde Zusammensetzung aufweist.
Molecular and functional imaging of breast cancer
Authors: Glunde K. , Jacobs M. A. , Pathak A. P. , Artemov D. , Bhujwalla Z. M. 
Published: September 2008

AbstractDespite several major advances in breast cancer diagnosis and treatment, the American Cancer Society has estimated that in the US alone 43 300 women and 400 men will die from breast cancer in 2007. Breast cancer typically is a multi‐focal, multi‐faceted disease, with the major cause of mortality being complications due to metastasis. Whereas a decade ago genetic alterations were the primary focus in cancer research, it is now apparent that the physiological tumor microenvironment, interactions between cancer cells and stromal cells such as endothelial cells, fibroblasts and macrophages, the extracellular matrix, and a multitude of secreted factors and cytokines influence progression, aggressiveness, and response of the disease to treatment. Prevention, early diagnosis, and treatment are the three broad challenges for MR molecular and functional imaging in reducing mortality from this disease. Multi‐parametric molecular and functional MRI provides unprecedented opportunities for identifying novel targets for imaging and therapy at the bench, as well as for accurate diagnosis and monitoring response to therapy at the bedside. Here we provide an overview of the current status of molecular and functional MRI of breast cancer, outlining some key developments, as well as identifying some of the important challenges facing this field in the future. Copyright © 2008 John Wiley & Sons, Ltd.
PGD on a recombinant allele: crossover between the TSC2 gene and ‘linked’ markers impairs accurate diagnosis
Authors: Altarescu Gheona , Eldar Geva Talia , Brooks Barry , Margalioth Ehud , Levy‐Lahad Ephrat , Renbaum Paul 
Published: September 2008

AbstractObjectiveAccounting for possible recombinations in developing an accurate preimplantation genetic diagnosis (PGD) protocol based on familial haplotypes.MethodsHaplotypes were constructed from genomic DNA in a family where the male was affected with tuberous sclerosis complex (TSC). Embryos were biopsied at day 3, and single blastomeres were analyzed by multiplex polymerase chain reactions (PCRs) including multiple microsatellite markers and single‐cell sequencing.ResultsInformative markers used in the initial haplotype analysis, based on the genomic DNA of the parents and affected child, were analyzed in the first PGD cycle. All embryos appeared to show recombination and none were transferred. Prior to the next cycle, the parents of the affected male were included in the haplotype analysis, demonstrating that the affected child had a recombinant allele. In the second PGD cycle, two nonrecombinant intragenic single nucleotide polymorphisms (SNPs) were used with the TSC2 mutation and four microsatellite markers for a second PGD cycle. In this cycle two wild‐type embryos were transferred, resulting in the birth of a healthy girl carrying the wild‐type TSC2 allele.ConclusionsPGD analysis requires the use of more than one meiosis for constructing accurate haplotypes. Testing for multiple closely linked markers and the familial mutation are necessary to detect recombination events and enable precise diagnosis. Copyright © 2008 John Wiley & Sons, Ltd.
Rapid prenatal diagnosis using uncultured amniocytes and oligonucleotide array CGH
Authors: Bi Weimin , Breman Amy M. , Venable Susan F. , Eng Patricia A. , Sahoo Trilochan , Lu Xin‐Yan , Patel Ankita , Beaudet Arthur L. , Cheung Sau Wai , White Lisa D. 
Published: September 2008

AbstractObjectiveOligonucleotide‐based array comparative genomic hybridization (array CGH) is an established method for detecting chromosomal abnormalities. Here, we explored the feasibility of using DNA extracted from uncultured amniocytes in amniotic fluid for array CGH on an oligonucleotide array platform.MethodsFifteen fetuses from 14 ongoing pregnancies were studied by array CGH on targeted oligonucleotide arrays with DNA isolated from direct amniotic fluid using a modified DNA extraction protocol.ResultsHigh‐quality array CGH results were obtained for 13 samples with suboptimal but interpretable results in only 2 samples due to limited DNA amounts. Array CGH using whole genome amplification (WGA) of DNA for the two cases with limited DNA was successful, and results were consistent with those from unamplified DNA. For another five samples, the results of array CGH with amplified DNA matched those with unamplified DNA. Chromosome analysis was performed for 14 cases and was consistent with array CGH results.ConclusionThis study demonstrates the feasibility of prenatal genetic diagnosis using oligonucleotide array CGH analysis for direct analysis of amniocytes without culturing cells. The use of oligonucleotide arrays increases the sensitivity and accuracy of detection over previous bacterial artificial chromosome (BAC)‐based arrays. Furthermore, the direct analysis allows for rapid array CGH results and shorter reporting time. Copyright © 2008 John Wiley & Sons, Ltd.
Gene expression in chorionic villous samples at 11 weeks' gestation from women destined to develop preeclampsia
Authors: Farina Antonio , Sekizawa Akihiko , De Sanctis Paola , Purwosunu Yuditiya , Okai Takashi , Cha Dong Hyun , Kang Jin Hee , Vicenzi Claudia , Tempesta Annalisa , Wibowo Noroyono , Valvassori Luisella , Rizzo Nicola 
Published: September 2008

AbstractObjectiveTo evaluate the direct alterations in mRNA expression among chorionic villous samples from 11 weeks' pregnant women who would develop preeclampsia (PE) later in the pregnancy.MethodCase‐control study encompassing five women destined to develop PE [cases matched 1:5 for gestational age (GA) with 25 controls]. We quantified mRNA expression on tissue samples from chorionic villous sampling (CVS) of normal and PE patients. We then assessed mRNA expressions of vascular endothelial growth factor (VEGFA), VEGFA receptor 1 (Flt‐1), endoglin (Eng), placental growth factor (PlGF), transforming growth factor‐β1 (TGF‐β1), heme oxygenase‐1 (HO‐1) and superoxide dismutase (SOD). Data were analyzed by nonparametric rank analysis.ResultsFor all the mRNA species considered in this study, all the mean observed ranks in the PE group were significantly altered compared to the rank expectation among controls. mRNA for Eng and TGF‐β1 were the markers with the highest degree of aberration in PE, in respect to controls. The results are consistent with those already reported for the corresponding circulating proteins. mRNA for HO‐1 and SOD were instead associated with the lowest aberration.ConclusionIt is assumed that the pathogenesis of PE is associated with pathophysiological alterations to trophoblasts in early gestation. Our study has directly proved that gene expressions relating to angiogenesis or oxidative stress are altered in the first trimester trophoblasts that go on to develop PE later. These results would put the basis for a possible screening method for PE by using residual CVS. Copyright © 2008 John Wiley & Sons, Ltd.
Preparation and characterization of nanoparticulate poly(N‐isopropylacryl‐ amide) hydrogel for the controlled release of anti‐tumour drugs
Authors: Blanco M Dolores , Guerrero Sandra , Teijón César , Olmo Rosa , Pastrana Lorenzo , Katime Issa , Teijón José M 
Published: September 2008

AbstractBACKGROUND: Poly(N‐isopropylacrylamide) (PNIPA) nanohydrogels were synthesized by inverse microemulsion to be used for the controlled release of anti‐tumour drugs. Different methods were used to obtain drug‐loaded xerogels, and their effect on drug release was studied, and evaluated using mathematical modelling.RESULTS: Nanoparticulate hydrogels, with a z‐average diameter of 170 nm, were loaded with 5‐fluorouracil (5‐FU), methotrexate (MTX) or mitomycin C (MMC) by using spray drying (SD) and freeze drying (FD). Xerogels obtained by SD consisted of individual and independent particles, whereas particles established interactions in xerogels obtained by FD. Total drug release took place at 6 and 7 h from 5‐FU‐loaded and MMC‐loaded xerogels prepared by SD, whereas MTX was expelled from the xerogels formed using the SD process. Drug release was slower from xerogels prepared by FD: 5‐FU at 32 h, MMC at 120 h and MTX at 240 h. The Higuchi model most aptly fits the dissolution data. Non‐Fickian and Fickian release behaviour can be attributed to SD and FD formulations, respectively.CONCLUSION: The amount of drug loaded, the morphology of xerogels as well as the drug release characteristics not only depend on the drug but also mainly on the process used to obtain the drug‐loaded PNIPA xerogels. Copyright © 2008 Society of Chemical Industry
Novel microporous poly(vinylidene fluoride)‐graft‐poly(tert‐butyl acrylate) electrolytes for secondary lithium batteries
Authors: Kader M Abdul , Kwak Soo Kyoung , Kang Seong Lak , Ahn Jou‐Hyeon , Nah Changwoon 
Published: September 2008

AbstractBACKGROUND: Much interest has recently been shown in improving the performance of lithium‐ion polymer batteries with gel polymer electrolytes (GPEs) due to a rapid expansion in industrial demand. Novel GPEs based on poly(vinylidene fluoride)‐graft‐poly(tert‐butyl acrylate) (PVDF‐g‐tBA) microporous mats are suggested in this study.RESULTS: Microfibrous polymer electrolytes were prepared using electrospinning and characterized for extent of grafting, morphology, crystallinity, electrochemical stability, ionic conductivity, interfacial resistance and cell cycleability. The degree of crystallinity was lower for tBA‐grafted PVDF mats than that of neat PVDF. The PVDF‐g‐tBA showed an improvement in the ionic conductivity, electrochemical stability, interfacial resistance and cyclic performance.CONCLUSION: The tBA‐grafted PVDF microporous electrolytes are promising candidates for enhancing the performance of lithium‐ion polymer batteries. Copyright © 2008 Society of Chemical Industry
Successive solution fractionation mechanisms for high‐density polyethylene
Authors: Stéphenne Vincent , Bailly Christian , Berghmans Hugo , Daoust Daniel , Godard Pierre 
Published: September 2008

AbstractBACKGROUND:Preparative fractionation techniques are currently used in order to obtain large amounts of polyethylene fractions. Preparative successive solution fractionation (SSF) and temperature rising elution fractionation (TREF) are compared as regards obtaining, at a multi‐gram scale, low‐dispersity fractions of high‐density polyethylene (HDPE). The operative separation mechanisms during a SSF of a broad HDPE, which are not yet totally elucidated, are also studied in this work.RESULTS:SSF and TREF approaches lead to the separation of HDPE macromolecules according to their molar masses. If very homogeneous fractions (dispersities from 1.1 to 1.3) are isolated in TREF at the lowest elution temperature, the collected mass is too low. At higher elution temperatures, the fractions have too broad a molar mass distribution (dispersities from 2.7 to 3.7). With the SSF procedure, dispersities are not as low as for the first TREF fractions. But, the relative weight fraction is better distributed between the different extraction temperatures. The molar mass distribution exhibits a dispersity of around 1.9.CONCLUSION:The SSF method is the most suitable way to obtain large gram amounts of low‐dispersity (ca2) HDPE fractions over a wide molar mass range. Complementary gram‐scale rheological characterization is thus possible enabling a better comprehension of the SSF mechanism. Liquid–liquid demixing is the main mechanism in SSF, but its relative importance depends on polymer characteristics and solvent quality. Copyright © 2008 Society of Chemical Industry
Polyimide films with antibacterial surfaces from surface‐initiated atom‐transfer radical polymerization
Authors: Li Liang , Ke Zhenjiang , Yan Guoping , Wu Jiangyu 
Published: September 2008

AbstractBACKGROUND: Materials with antibacterial surface properties have attracted extensive scientific interest for research and development in the battle against microbial contamination. The application of antimicrobial polymers minimizes environmental problems and enhances the efficiency, selectivity and lifetime of the antimicrobial agents. In this paper polyimide (PI) films are chosen as the polymeric substrate to be modified due to the good thermal, mechanical and physicochemical properties of PI. The method of preparing PI films with antibacterial surfaces using surface‐initiated atom‐transfer radical polymerization (ATRP) is described.RESULTS: The results from X‐ray photoelectron spectroscopy showed that the surfaces at each stage were modified successfully. The pyridinium groups introduced on the PI surface possessed antibacterial properties and the bactericidal effect of the functionalized PI films on Escherichia coli was evaluated. Quaternization of the pyridine rings of the poly(4‐vinylpyridine) (P4VP) brushes gave rise to a high concentration of quaternary pyridinium groups on the PI film surfaces. The antibacterial efficiency of the modified PI film was dependent on the amount of quaternary pyridinium groups on the surface.CONCLUSION: In this research, functional polymer brushes of P4VP were prepared via surface‐initiated ATRP from PI films, followed by alkylation of the grafted P4VP with hexyl bromide. The surface functionalization method described has the advantage of being effective in conferring antibacterial properties on polymeric materials. Copyright © 2008 Society of Chemical Industry
Effect of montmorillonite modification on the behaviour of polyamide/polystyrene blends
Authors: Kelnar Ivan , Rotrekl Jakub , Kotek Jiří , Kaprálková Ludmila 
Published: September 2008

AbstractBACKGROUND: In nanocomposites with multiphase matrices, the addition of layered silicate not only has a reinforcing effect, but also changes significantly the morphology, namely the size and the structure of the dispersed phase. In this paper, we focus on systems with polyamide 6 (PA6)/polystyrene (PS) matrices. The effect of clay was studied over the whole composition range together with the simultaneous variation of basic parameters influencing the structure and mechanical behaviour, i.e. the clay treatment type and mixing protocol.RESULTS: At all compositions, remarkable refinements of both particulate and co‐continuous structures by clay were found. This effect and a significant shift of the glass transition temperature of blend components were more pronounced for clay with less polar treatment as a result of distinct localization of clay in the interfacial area (due to its lower affinity for PA6 phase). An increase in modulus was found at all compositions, whereas strength and toughness were enhanced at low PS contents only, as a consequence of small particle size and enhanced interfacial bonding.CONCLUSIONS: The results presented indicate that nanosilicates can effectively influence the structure and properties of PA6/PS blends. Copyright © 2008 Society of Chemical Industry
Comparative proteomic analysis of human placenta derived from assisted reproductive technology
Authors: Zhang Yu , Zhang Yan‐Ling , Feng Chun , Wu Yan‐Ting , Liu Ai‐Xia , Sheng Jian‐Zhong , Cai Jie , Huang He‐Feng 
Published: September 2008

AbstractThe aim of this study was to use proteomics‐based approach to examine differences in protein expression in placenta derived from assisted reproductive technology (ART) and normal pregnancy. Using 2‐DE we found that, compared with the control group, 12 spots in standard in vitro fertilization group and 18 spots in intracytoplasmic sperm injection group were identified as significantly differentially expressed proteins. Among them, six spots were differentially expressed in both standard IVF and ICSI groups with the same change tendency. Totally, 20 proteins were successfully identified by MALDI TOF/TOF MS, including proteins involved in the membrane traffic, metabolism, nucleic acid processing, stress response and cytoskeleton. Notably, five proteins detected to be differentially expressed in both ART groups were identified as annexin A3, hnRNP C1/C2, α‐SNAP, FTL and ATP5A. Some of the proteins were confirmed by Western blot and immunohistochemistry analysis. Our study allowed for the initial identification of these proteins related to various functions in placentation with significantly altered abundance in ART groups. The present results reveal that abnormal protein profiles are involved in ART placenta and these differentially expressed proteins may be valuable for the evaluation of potential association between ART treatment and offspring outcome.
Synthesis and evaluation of new thienyl and bithienyl‐bis‐indolylmethanes as colorimetric sensors for anions
Authors: Batista Rosa M. F. , Oliveira Elisabete , Nuñez Cristina , Costa Susana P. G. , Lodeiro Carlos , Raposo M. Manuela M. 
Published: September 2008

AbstractThe synthesis and full characterization of new bis‐indolylmethanes containing thienyl and bithienyl moieties are reported. The sensor ability of the compounds in the presence of halide ions (F−, Cl−, Br−, and I−), NO, ClO, SO, CN−, and OH− ions was investigated in acetonitrile. The experimental results indicate that they could act as selective chromogenic‐sensing molecules for the most basic anions F−, CN−, and OH−, as a well‐defined color change from yellow to pink was observed. The interaction constants between compounds 1 and 2 in the presence of F−, CN−, and OH− were calculated and increased in the order OH− > F− > CN−. Copyright © 2008 John Wiley & Sons, Ltd.
Evolution of iron catalysts for effective living radical polymerization: P–N chelate ligand for enhancement of catalytic performances
Authors: Uchiike Chihiro , Ouchi Makoto , Ando Tsuyoshi , Kamigaito Masami , Sawamoto Mitsuo 
Published: September 2008

AbstractIron catalysts were evolved for more active transition metal‐catalyzed living radical polymerization through design of the ligands. In situ introduction of P–N chelate‐ligands, consisting of hetero‐coordinating atoms [phosphine (P) and nitrogene (N)], onto FeBr2 effectively catalyzed living radical polymerization of methyl methacrylate (MMA) in conjunction with a bromide initiator, where the monomer‐conversion reached over 90% without dropping the rates and the molecular weights of obtained PMMAs were well controlled. The benign effects of the “hetero‐chelation” were demonstrated by comparative experiments with homo‐chelate ligands (P–P, N–N), model compounds of the composed coordination site, and the combinations. We successfully achieved an isolation of iron complex with a P–N ligand [FeBr2(DMDPE); DMDPE: (R)‐N,N‐dimethyl‐1‐(2‐(diphenylphosphino)phenyl)‐ethanamine], which was superior to the conventional catalyst [FeBr2(Pn‐Bu)2] with respect to controllability and activity, especially at the latter stage. The catalyst was almost quantitatively removed by water washing after polymerization. It was also effective for living polymerization of styrene. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6819–6827, 2008