bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biphasic calcium phosphate: A comparative study of interconnected porosity in two ceramics
Authors: Lecomte A. , Gautier H. , Bouler J. M. , Gouyette A. , Pegon Y , Daculsi G. , Merle C. 
Published: September 2007

AbstractInterconnection, one of the main structural features of macroporous calcium‐phosphate ceramics, contributes to the biological and physicochemical properties of bone substitutes. As no satisfactory method exists for evaluating this feature, analysis was performed to determine the permeability, tortuosity, and equivalent diameter of interconnecting channels, that is the parameters that appear to be representative of the way pores are linked. The testing of two ceramics with similar porosity levels revealed important differences in all three interconnection parameters. One ceramic showed poor permeability, corresponding to a small equivalent diameter for interconnecting channels in conjunction with a high tortuosity factor, while the other displayed high permeability, a large diameter for interconnecting channels, and a low tortuosity factor. The methodology used, which can be applied to the quantification of interconnection in all calcium‐phosphate ceramics, constitutes the first step in a complete study of the role of this feature in cellular colonization of the ceramic, matrix dissolution, and drug release from the calcium‐phosphate matrix. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Fibrous and Helical Calcite Crystals Induced by Synthetic Polypeptides ContainingO‐Phospho‐L‐Serine andO‐Phospho‐L‐Threonine
Authors: Hayashi Shinya , Ohkawa Kousaku , Suwa Yukie , Sugawara Tetsunori , Asami Takahiro , Yamamoto Hiroyuki 
Published: September 2007

AbstractThe modification of CaCO3crystal growth by syntheticL‐Ser(PO3H2) andL‐Thr(PO3H2) containing polypeptides is described. The amino acids Gly,L‐Glu,L‐Asp,L‐Ser,L‐Ala, andL‐Lys induced rhombohedral calcite with a rough surface. Dipeptides, Xaa‐L‐Ser(PO3H2) (Xaa = Gly,L‐Glu,L‐Asp,L‐Ser,L‐Ala andL‐Lys) induced vaterite crystals in the lower [Ca2+]. On the other hand,L‐Ser(PO3H2)‐containing polypeptides formed spherical vaterite and fibrous calcite. The characteristic helical calcite was found in the presence of copoly[L‐Ser(PO3H2)75L‐Asp25] or poly[L‐Ser(PO3H2)3–L‐Asp]. Fibrous calcite, spherical vaterite, and helical calcite crystals were subjected to XRD and EDX analysis. XRD revealed the specific faces of these crystals. EDX spectra and surface analysis visualized the localization of the polypeptides and CaCO3components. Together with TEM and SAED data, we propose hypothetical growth mechanisms for the fibrous and helical calcite crystals.magnified image
Viscoelastic Properties of Chitosan with Different Hydration Degrees as Studied by Dynamic Mechanical Analysis
Authors: Mano João F. 
Published: September 2007

AbstractDynamic mechanical analysis, DMA, is an adequate technique for characterizing the mechanical features of biomaterials, as one can use test conditions that can more closely simulate the physiological environments in which they are going to be applied. In this work it was possible to perform different tests on chitosan membranes using low/moderate hydration levels, as well in completely wet conditions. In the first case the data obtained at different relative humidity environments were rationalized under a time‐humidity superposition principle, where a master curve for the storage modulus could be obtained along a wide range of frequencies. The temperature dependence of the shift factors exhibited a curvature opposite to that expected by the WLF equation, and is consistent with relaxation dynamics behavior below the glass transition. Temperature scans above room temperature in both dry and wet conditions did not reveal strong variations in the viscoelastic properties. It was possible to follow in real time the water uptake in an initially‐dry membrane. During the initial strong and fast decrease of the storage modulus the loss factor exhibited a peak that should correspond to the occurrence of the glass transition resulting from the plasticization effect of water. Upon equilibration the loss factor reached similar values as for the dry material (tanδ ≈ 0.5). The viscoelastic characterization reported in this work for chitosan may be useful in the use of such material for a variety of biomedical applications.magnified image
1H‐13C CPMAS and T2 Relaxation Solid‐State NMR Measurements of Melamine‐Based Polycondensed Chemical Gels
Authors: Egger Chrystelle C. , Schädler Volker , Hirschinger Jérôme , Raya Jésus , Bechinger Burkhard 
Published: September 2007

AbstractGel networks prepared from aqueous melamine‐formaldehyde resins via a sol–gel route were characterised by 13C CPMAS (where MAS stands for magic angle spinning)‐NMR and T2 relaxation. We show that within the aqueous networks, the type and amount of functional groups on the melamine ring is strongly influenced by the initial melamine/formaldehyde ratio, the sol concentration and the amount of catalyst. Residual methylol groups can be etherified by postalkoxylation using primary alcohols resulting in chemical gels with different bridging units and residual ether linkages as also confirmed by T2 measurements. In addition, in the case of initially alkoxylated gels the alcoholysis process can be followed by varying the amount of catalyst used.magnified image
Thiol‐ene Hybrid Organic/Inorganic Nanostructured Coatings Based on Thiol‐Functionalized Zirconium Oxoclusters
Authors: Sangermano Marco , Gross Silvia , Priola Aldo , Rizza Giancarlo , Sada Cinzia 
Published: September 2007

AbstractThe thiol‐functionalized zirconium oxocluster Zr12(µ3‐O)8(µ3‐OH)8(MP)24 · 4MPA was used as inorganic nanosized building block in the thiol‐ene photopolymerization of APE and TH in a 1:1 molar mixture. Transparent and crack‐free coatings were obtained, and TEM analysis showed that the inorganic particles are well dispersed within the polymeric network with no significant macroscopic agglomeration. An increase of Tg values, storage modulus in the rubbery region, and thermal stability were evidenced by increasing the zirconium oxocluster content in the photocurable formulations. XPS analysis and SIMS depth profile were carried out on UV cured films and showed the presence of a homogeneously distributed zirconium oxocluster.magnified image
Fabrication and Photocatalytic Activities of Morphology‐Controlled Titania Nanoobject Arrays by Block Copolymer Templates
Authors: Peng Juan , Li Xue , Kim Dong Ha , Knoll Wolfgang 
Published: September 2007

AbstractWe report a simple scheme to fabricate organic/inorganic hybrid nanostructures with extraordinary morphologies by one‐step spin coating, using a PS‐b‐PEO diblock copolymer as template coupled with sol‐gel chemistry. The shape and size of the titania nanoobject can be fine‐tuned by controlling the amount of sol‐gel precursor relative to PS‐b‐PEO and the composition of the precursor. Ordered arrays of nanoscopic titania objects such as nanodots, nanobowls, and nanonetworks were obtained from the initial hybrid nanostructures by removing the organic matrix by UV treatment. Photocatalytic activities of the resulting titania nanoobjects were investigated in terms of the degradation of a typical dye.magnified image
Crystallization behaviors and mechanical properties of poly(ethylene 2,6‐naphthalate)/multiwall carbon nanotube nanocomposites
Authors: Kim Jun Young , Han Sang‐Il , Kim Seong Hun 
Published: September 2007

AbstractCarbon nanotube (CNT)‐reinforced poly(ethylene 2,6‐naphthalate) (PEN) nanocomposites were prepared by direct melt blending process in a twin‐screw extruder. There is significant dependence of the crystallization and melting behavior of PEN/CNT nanocomposites on CNT content and crystallization temperature. The incorporation of CNT may favor the formation of the β‐form crystals in PEN/CNT nanocomposites, and more CNT content amplified this effect. In this PEN/CNT nanocomposite system, the CNT promoted the nucleation and the growth with higher crystallization rate of PEN/CNT nanocomposites, and simultaneously reduced the fold surface free energy and the work required in folding polymer chains in the polymer nanocomposites. In addition, the incorporation of a very small quantity of CNT significantly improved the mechanical properties of PEN/CNT nanocomposites. POLYM. ENG. SCI., 47:1715–1723, 2007. © 2007 Society of Plastics Engineers
Ultrasonic measurement of residual wall thickness during gas assisted injection molding
Authors: Brown E.C. , Mulvaney‐Johnson L. , Coates P.D. 
Published: September 2007

AbstractUltrasonic technology provides a powerful and noninvasive method of in‐process measurement during injection molding and extrusion. Changes in the velocity, attenuation and reflection coefficients of high frequency sound waves can be related to the state and conditions of the materials through which they propagate. The velocity of an ultrasonic wave changes with density and elastic moduli; this allows information on solidification and material properties to be collected during the molding cycle. The time of flight of the wave is a function of velocity and path length. This paper shows that it can be correlated with the residual wall thickness of polymer in the mold during gas assisted injection molding. POLYM. ENG. SCI., 47:1730–1739, 2007. © 2007 Society of Plastics Engineers
Anisotropic shrinkage of injection molded poly vinylidene fluoride samples
Authors: Speranza V. , Pantani R. , Besana G.B. , Titomanlio G. 
Published: September 2007

AbstractA study of as‐molded shrinkage of Poly Vinylidene Fluoride (PVDF) injection molded samples was carried out in this work. The polymer was injected into a simple rectangular cavity under different holding pressures, and the dimensions of the resulting samples were accurately measured at room temperature 10 min after demolding. As expected, the relative difference between the sample dimensions and the corresponding cavity dimensions (namely the shrinkage) decreased on increasing holding pressure. Furthermore, the shrinkage increased on increasing distance from the injection point. A somewhat unexpected feature of experimental data was the fact that the shrinkage was much higher along the flow direction than along the transverse on‐plane direction. A thorough characterization of the elastic properties of the solid samples also showed a marked anisotropy of the elastic modulus and of the coefficient of linear thermal expansion. The injection molding tests were simulated by a software developed at University of Salerno to obtain the evolution of temperature, pressure, and crystallinity inside the samples. The predicted pressure profiles were satisfactorily compared with the measured values. The simulated histories of temperature, pressure and crystallinity were used as input for a thermomechanical model for shrinkage evolution. It was found that the reason for anisotropy in shrinkage had to be ascribed mainly to the anisotropy in material properties. It was in fact shown that, adopting the correct anisotropic values for the elastic modulus and thermal expansion coefficient, a satisfactorily description of shrinkage data could be reached. POLYM. ENG. SCI., 47:1788–1795, 2007. © 2007 Society of Plastics Engineers
Comparison between surface renewal devolatilizing performances of different screw extruders
Authors: Wang Ning He 
Published: September 2007

AbstractThe concept of surface renewal for polymer devolatilization (DV) in screw extruder was defined based on the traditional penetration theory, and a measuring criterion and comparing methods for comparing surface renewal devolatilizing performance (SRDP) between different extruders and between different types of extruders were proposed based on this concept and the extrusion–devolatilization theory previously developed by the authors. Their proprieties were further verified by using the literature data obtained in a single screw extruder (SSE) and an intermeshing co‐rotating twin‐screw extruder (ICoTSE). Moreover, the effects of some important screw geometry factors on the SRDPs of both the extruders were discussed, and the comparisons of the SRDPs between them and between types of SSE and ICoTSE were given and discussed. POLYM. ENG. SCI., 47:1920–1926, 2007. © 2007 Society of Plastics Engineers
A short review on rubber/clay nanocomposites with emphasis on mechanical properties
Authors: Sengupta R. , Chakraborty S. , Bandyopadhyay S. , Dasgupta S. , Mukhopadhyay R. , Auddy K. , Deuri A.S. 
Published: September 2007

AbstractThe invention of Nylon‐6/clay nanocomposites by the Toyota Research Group of Japan heralded a new chapter in the field of polymer composites. This article highlights the work done in the field of rubber/clay nanocomposites. The preparations of rubber/clay nanocomposites by solution blending, latex compounding, and melt intercalation are covered and a thorough discussion of the mechanical properties of the various rubber/clay nanocomposite systems is presented. Other properties such as barrier, dynamic mechanical behavior, and thermal properties are also discussed. Finally, the future trends in the rubber/clay nanocomposites are mentioned. POLYM. ENG. SCI., 47:1956–1974, 2007. © 2007 Society of Plastics Engineers
Serum proteomics of lung adenocarcinomas induced by targeted overexpression of c‐raf in alveolar epithelium identifies candidate biomarkers
Authors: Chatterji Bijon , Borlak Jürgen 
Published: September 2007

AbstractWe previously reported a proteome map of lung adenocarcinomas in serine‐threonine kinase of the Raf family (c‐raf) transgenic mice. We now extend our initial studies to serum proteins at early stage (1 month) and advanced stages of tumorigenesis (12 months). Notably, serum proteins from wild‐type and tumor bearing mice were extracted with a lysis buffer containing 5 mol/L urea, 2 mol/L thiourea, 40 mmol/L Tris, 4% CHAPS, 100 mmol/L DTT, 0.5% BioLyte 3–10, separated by 2‐DE and studied by image analysis. On average 400 protein spots per gel were excised and analyzed by MALDI‐TOF MS. We identified 45 common and 5 uniquely expressed proteins in wild‐type and tumor bearing mice. Apart from uniquely identified proteins we observed for n = 9 proteins differential expression when wild‐type and tumor bearing mice were compared. This included serpins and other protease inhibitors, lipocalins, transthyretins, globins, and Igs. Notably, we demonstrate significant regulation of alpha‐1‐antitrypsin, alpha‐2‐macroglobulin, hemoglobin subunit alpha, vitamin D‐binding protein, major urinary proteins, and transthyretin (up to eight‐fold) in serum of lung tumor bearing mice. Disease association of these proteins in human malignancies has been reported. Thus, an identification of regulated serum proteins in this lung cancer disease model provides excellent opportunities for the search of novel biomarkers.
Nitric oxide gas sensors with functionalized carbon nanotubes
Authors: Mäklin Jani , Mustonen Tero , Kordás Krisztián , Saukko Sami , Tóth Géza , Vähäkangas Jouko 
Published: September 2007

AbstractNitric oxide (NO) gas sensing with carboxyl functionalized single‐ and multi‐walled carbon nanotubes (SWCNTs and MWCNTs) is demonstrated in this work. Stable solutions of the carboxylated nanotubes were made and then drop‐cast on alumina substrates equipped with gold electrodes and also with platinum heater elements. The obtained resistive nanotube sensors were tested in a 2‐point setup at different temperatures and NO gas concentrations up to 100 ppm in synthetic air and also in argon buffer. When exposed to NO, the conductivity of the sensors changed up to ∼40% for SWCNTs and ∼12% for MWCNTs; however, in the investigated regime, the response was found to be fairly independent on NO concentration. Though all sensors showed practically instantaneous gas response, the time needed for saturation (few tens of minutes) was found to be concentration dependent. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman spectroscopy of (n,m)‐identified individual single‐walled carbon nanotubes
Authors: Michel T. , Paillet M. , Meyer J. C. , Popov V. N. , Henrard L. , Poncharal P. , Zahab A. , Sauvajol J.‐L. 
Published: September 2007

AbstractThe goal of our “complete experimental” approach was to relate the Raman response of an individual single‐walled carbon nanotubes (SWNT) to its (n,m) structure determined from an independent way. In this aim, a procedure including transmission electronic microscopy (TEM), Raman spectroscopy, and electron diffraction experiments on the same SWNT has been developed. The independent determinations of both structure and Raman features of semiconducting and metallic nanotubes allows to discuss several questions concerning: (i) the relation between diameter of the tubes and the radial breathing mode (RBM) frequency, (ii) the values and the nature of the $ E ^{\rm S}_{33} $ and $ E ^{\rm S}_{44} $ optical transition energies. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inkjet printing of transparent and conductive patterns of single‐walled carbon nanotubes and PEDOT‐PSS composites
Authors: Mustonen Tero , Kordás Krisztián , Saukko Sami , Tóth Géza , Penttilä Jari S. , Helistö Panu , Seppä Heikki , Jantunen Heli 
Published: September 2007

AbstractTransparent and conductive patterns of carboxyl functionalized single‐walled carbon nanotubes (SWCNT‐COOHs) and the composites of those with poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT‐PSS) were deposited on various substrates by inkjet printing. For low print repetitions, the PEDOT‐PSS/SWCNT‐COOH composite patterns show enhanced conductance as compared to the corresponding PEDOT‐PSS conductors. The results suggest a decreased percolation threshold for the printed composite since the nanotubes establish electrical interconnections between the separate PEDOT‐PSS (conductive phase) islands being dispersed in the insulating PSS‐phase. However, the interaction between PEDOT‐PSS and SWCNTs becomes insignificant and the conductivity is not enhanced by the nanotubes, when the amount of PEDOT‐PSS is sufficient to form a continuous conducting phase. Up to now, patterns having sheet resistivities as low as ∼1 kΩ/□ could be achieved. Though there is a trade‐off between transparency and conductivity – we achieved highly transparent patterns (∼90%) with a reasonably low resistivity of ∼10 kΩ/□. The ink and printing method proposed here offer new alternatives of conventional transparent conductive materials based on either polymers or indium oxides; and pose scaleable production of cost‐effective transparent electronics. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic transport measurements in graphene nanoribbons
Authors: Han Melinda , Ozyilmaz Barbaros , Zhang Y. , Jarillo‐Herero P. , Kim Philip 
Published: September 2007

AbstractWe review recent experiments at Columbia on electronic transport in graphene nanostructures. We define the graphene nanostructures by e‐beam lithography followed by oxigen plasma etch. In this way we can pattern nanoribbons, rings, as well as other nanostructures. We use this technique to pattern graphene nanoribbons and study the formation of a band gap due to transverse electron confinement. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thin transparent carbon nanotube networks: effects of ion irradiation
Authors: Kaiser A. B. , Skákalová V. , Roth S. 
Published: September 2007

AbstractWe investigate the effect of irradiation by Ar+ and N+ ions on the properties of thin transparent networks of single‐wall carbon nanotubes (SWNTs). The irradiation produces a small reduction in the infra‐red transmittance of the networks at a wavelength of 2000 nm that correlates with the much larger reduction in conductance, and the peaks in the infra‐red‐visible absorbance spectrum are strongly reduced. Ion irradiation greatly increases the localization of the charge carriers, suppressing the conductance at low temperatures more severely than at room temperature. The conductance follows variable‐range hopping behaviour for all samples. Nonlinearity in the current–voltage characteristics of the thin SWNT networks is observed only at very low temperatures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cardiofemoral index as an ultrasound marker of fetal anemia in isoimmunized pregnancy
Authors: Cabral A.C.V. , Reis Z.S.N. , Leite H.V. , Lage E.M. , Ferreira A.L.P. , Melo I.G. 
Published: September 2007

AbstractObjectiveTo test a new noninvasive ultrasound method for diagnosing fetal anemia in red blood cell isoimmunized pregnancies.MethodsA diagnostic accuracy study was carried out to determine the cutoff point of an ultrasound measurement, the cardiofemoral index (CFI), calculated using the biventricular outer dimension (BVOD) and femur length to diagnosis severe anemia. The CFI measurement was performed before each of the 336 cordocenteses on 131 fetuses. Diagnosis test analysis and receiver–operating characteristics (ROC) curves were used and the area under the curve (AUC) was calculated to compare the overall accuracy of the CFI for anemia diagnosis, between fetuses with or without previous intrauterine transfusions (IUT).ResultsAt first cordocentesis (n = 131) the AUC was 0.75 (95% CI, 0.66–0.84). For cases where fetuses had undergone 1 previous transfusion (n = 88) the AUC was 0.76 (95% CI, 0.64–0.88) and at the time of the third cordocentesis for IUT (n = 53) it was 0.73 (95% CI, 0.59–0.86). For a 0.59 CFI threshold to diagnosis fetuses with hemoglobin deficit above 5 g/dL, sensitivity values were 87.2%, 88.0%, and 94.1% respectively for fetuses without IUT, with 1 IUT, and with 2 IUTs. Likelihood ratios for positive (LR+) and negative (LR−) test results were 1.98, 2.05, 1.69 and 0.23, 0.21, 0.13 respectively.ConclusionThe cardiofemoral index may be an effective noninvasive marker of severe fetal anemia in high‐risk fetuses, with accuracy similar for fetuses either with or without previous transfusions.
Morbidity in the first year postpartum among HIV‐infected women in Kenya
Authors: Chersich M.F. , Luchters S.M. , Yard E. , Othigo J.M. , Kley N. , Temmerman M. 
Published: September 2007

AbstractObjective: To assess the effects of HIV infection on morbidity and the needs of infected women for services in the first year postpartum. Methods: A cross‐sectional study with 500 women attending a child‐health clinic in Mombasa, Kenya. Results: Postpartum duration was a median of 3.3 months (interquartile range, 1.9–6.1 months). The 54 HIV‐infected women had a lower income and less financial support than the uninfected women, and they were more likely to experience fever, dyspnea, and dysuria, and to have genital warts (odds ratio [OR], 9.6; 95% confidence interval [CI], 2.6–35.6; P < 0.001), candidiasis (OR, 2.9; 95% CI, 1.2–6.8; P = 0.012), and bacterial vaginosis (OR, 1.8; 95% CI, 0.95–3.3; P = 0.066). Six (nearly 15%) of the HIV‐infected women had low‐ or high‐grade squamous intraepithelial lesions, and 21 (42%) had an unmet need for contraception. More than half of all women were anemic, and normocytic anemia was predominant among the HIV infected. Conclusion: Compared with uninfected women, morbidity was increased for HIV‐infected women during the year following delivery. This period could be used to offer these, and all‐women, family planning services, cervical cancer screening, and treatment for anemia and reproductive tract infections.