bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composite Worm‐Like Aggregates Formed from a Pair of Block‐Copolymers Containing Hydrogen‐Bonding Donor and Acceptor
Authors: Xiong De'an , Shi Linqi , Jiang Xiaowei , An Yingli , Chen Xi , Lü Juan 
Published: January 2007

AbstractWorm‐like aggregates with a PAA/P4VP complex core and a PEG/PNIPAM mixed shell were prepared in ethanol by the comicellization of poly(ethylene glycol)‐block‐poly(acrylic acid) (PEG‐b‐PAA) and poly(N‐isopropylacrylamide)‐block‐poly(4‐vinylpyridine) (PNIPAM‐b‐P4VP) through hydrogen‐bonding. The formed aggregates were studied by dynamic light scattering, static light scattering, 1H NMR, and transmission electron microscopy. The length of worm‐like aggregates could be adjusted by changing the weight ratio of W(PNIPAM‐b‐P4VP)/W(PEG‐b‐PAA). When the ratio changed from 20 to 150%, the length changed from about 100 nm to several microns, and the diameter stayed almost unchanged at about 15 nm.magnified image
Thermal Degradation Behavior and Kinetic Analysis of Biodegradable Polymers Using Various Comparative Models, 1
Authors: Shih Yeng‐Fong , Chieh Yu‐Chih 
Published: January 2007

AbstractThermal degradation behavior of a biodegradable polymer (PBS) has been investigated by conventional and MTGA methods. The kinetic parameters of degradation were calculated by a general analytical solution and by the Coats‐Redfern, Ozawa, Horowitz‐Metzger, and MTGA methods. The results reveal that the reaction mechanism at lower temperature is probably the F1 model through the reaction of random chain cleavage via cis‐elimination. However, the reaction mechanism at higher temperature is likely to be D1 model because of the dominant diffusion control effect.magnified image
Semigroup approach for identification of the unknown diffusion coefficient in a quasi‐linear parabolic equation
Authors: Demir Ali , Ozbilge Ebru 
Published: January 2007

AbstractThis article presents a semigroup approach for the mathematical analysis of the inverse coefficient problems of identifying the unknown coefficient k(u(x,t)) in the quasi‐linear parabolic equation ut(x,t)=(k(u(x,t))ux(x,t))x, with Dirichlet boundary conditions u(0,t)=ψ0, u(1,t)=ψ1. The main purpose of this paper is to investigate the distinguishability of the input–output mappings Φ[⋅]:𝒦 →C1[0,T], Ψ[⋅]:𝒦→C1[0,T] via semigroup theory. In this paper, it is shown that if the null space of the semigroup T(t) consists of only zero function, then the input–output mappings Φ[⋅] and Ψ[⋅] have the distinguishability property. It is also shown that the types of the boundary conditions and the region on which the problem is defined play an important role in the distinguishability property of these mappings. Moreover, under the light of measured output data (boundary observations) f(t):=k(u(0,t))ux(0,t) or/and h(t):=k(u(1,t))ux(1,t), the values k(ψ0) and k(ψ1) of the unknown diffusion coefficient k(u(x,t)) at (x,t)=(0,0) and (x,t)=(1,0), respectively, can be determined explicitly. In addition to these, the values ku(ψ0) and ku(ψ1) of the unknown coefficient k(u(x,t)) at (x,t)=(0,0) and (x,t)=(1,0), respectively, are also determined via the input data. Furthermore, it is shown that measured output data f(t) and h(t) can be determined analytically by an integral representation. Hence the input–output mappings Φ[⋅]:𝒦→ C1[0,T], Ψ[⋅]:𝒦→C1[0,T] are given explicitly in terms of the semigroup. Copyright © 2007 John Wiley & Sons, Ltd.
A Reduced Third Order Markov Model for Ethylene‐Norbornene Copolymerization Kinetics with Homogeneous Metallocene Catalysts
Authors: Park Seung Young , Lee Jongku , Choi Kyu Yong 
Published: January 2007

AbstractA reduced third order Markov model is presented to model the kinetics of ethylene‐norbornene copolymerization over rac‐Et(1‐indenyl)2ZrCl2/methylaluminoxane catalyst in solution. In our previous work, we developed a penultimate model (second order Markov model) to describe the copolymerization rate behavior and the copolymer composition. Although the penultimate model provides better predictions of the polymerization kinetics than a simple terminal model, it tends to give underestimated norbornene incorporation rates at high norbornene/ethylene mole ratios in the bulk liquid phase. In this work, we propose a modified third order Markov model to improve the model's capability of calculating norbornene incorporation rate and comonomer sequence distribution. The model parameters have been estimated using a parameter optimization technique. The model simulation results indicate that the rate constant for norbornene insertion into a growing chain depends upon the norbornene microblock length at the propagating center.magnified image
Method for Quantitative Evaluation of Kinetic Constants in Olefin Polymerizations, 3
Authors: Matos Válter , Moreira Maurício , Neto Antônio G. Mattos , Nele Márcio , Melo Príamo A. , Pinto José Carlos 
Published: January 2007

AbstractA method for the quantitative evaluation of kinetic constants in Ziegler–Natta and metallocene olefin homopolymerizations presented previously (V. Matos, A. G. M. Neto, J. C. Pinto, J. Appl. Polym. Sci. 2001, 79, 2076; V. Matos, A. G. M. Neto, M. Nele, J. C. Pinto, J. Appl. Polym. Sci. 2002, 86, 3226) is extended to allow for estimation of model parameters in copolymerization reactions. The method is used to estimate kinetic parameters of ethylene/propylene copolymerization during the synthesis of high impact poly(propylene) in a train of cascade reactors. Process models were developed to describe the reaction rate profile, reactor solubles, molecular weight distribution of the total polymer, xylene solubles, and insoluble polymer. The process models and the estimated parameters were inserted into a process simulator that successfully described the industrial process.magnified image
Ultrasonically Initiated Grafting of Maleic Anhydride onto Poly(propylene)
Authors: Tan Xiumin , Xu Yongshen , Jia Guangwei , Qian Jun 
Published: January 2007

AbstractThis paper presents the studies on the grafting of MAH onto PP performed in solution by means of ultrasonic initiation. The effect of sonic intensity and monomer concentration on the amount of grafted MAH was investigated. It was found that grafting reaction could be initiated by ultrasound at ambient temperatures in the absence of an initiator. The quantity of product grafted was found to be 1.35%. It has been shown that optimum conditions for grafting are reached at an ultrasonic intensity of 300 W and a MAH concentration of 30%. PP‐g‐MAH is characterized by FTIR and XRD. DSC shows that the crystallinity of PP‐g‐MAH is lower than that of pure PP.magnified image
Contributions to the Experimental Investigation of the Nascent Polymerisation of Ethylene on Supported Catalysts, 1
Authors: Di Martino Audrey , Weickert Guenter , McKenna Timothy F. L. 
Published: January 2007

AbstractA detailed investigation of the kinetics, morphology and polymer properties observed during the polymerisation of ethylene on a Ziegler‐Natta catalyst at very short times (t ≥ 40 ms) in a novel, quenched‐flow reactor is presented. It was found that for times shorter than a tenth of a second, the observed rate of polymerisation was significantly higher than expected, and that the crystallinity of the nascent ethylene homopolymer was of the order of 25 to 30% – much lower than expected. Evidence is presented that shows that fragmentation is essentially complete in a small fraction of a second.magnified image
An Experimental and Theoretical Investigation into the Diffusion of Olefins in Semi‐Crystalline Polymers: The Influence of Swelling in Polymer‐Penetrant Systems
Authors: Kanellopoulos Vassileios , Mouratides Dimitrios , Tsiliopoulou Evantia , Kiparissides Costas 
Published: January 2007

AbstractA comprehensive dynamic diffusion model is developed to calculate the diffusion coefficients of low molecular weight penetrants (i.e.,α‐olefins) in semi‐crystalline polyolefins from dynamic sorption measurements. The model also takes into account the extent of polymer swelling on the penetrant diffusion flux, resulting in a moving boundary value problem. The free volume theory is employed to calculate the dependence of the diffusion coefficient on the penetrant concentration. The solubilities and diffusivities of ethylene and propylene in semi‐crystalline high density polyethylene films were measured at different temperatures and pressures, using a Rubotherm® magnetic suspension microbalance operated in series with an optical view cell for the measurement of the degree of polymer swelling. It is shown that model predictions are in excellent agreement with the experimental dynamic measurements on the mass uptake of the sorbed species. Moreover, it is shown that the proposed model can predict correctly the diffusion coefficient ofα‐olefins in semi‐crystalline polyolefins.magnified image
Endoscopic fetal surgery: in vitro thermic effect of electrosurgical units
Authors: Ciardelli Valentina , Caroli Elena , Corazza Ivan , Segata Maria , Zannoli Romano , Rizzo Nicola 
Published: January 2007

AbstractObjectiveThe study focused on the safety of electrosurgical devices in endoscopic fetal surgery. The thermic effects of monopolar electric waves were studied in vitro in order to obtain safety indications in terms of mode of intramniotic application of electrical devices (time and number of shots; volts; and distance from tissues to be preserved).Study designA glass model filled with saline solution, and an electrical device with resistor and voltage supply, were constructed to reproduce the physical effects of thermic conductivity in vitro; a Swan‐Ganz thermic sensor was used to measure the temperature inside the beuta. Different series of tests were carried out.ResultsThe maximal increase (8.60 ± 0.04 °C) takes place at the external surface of the resistor (distance: 0 cm), while at 2 cm, the temperature of the saline solution does not change.ConclusionsOur tests demonstrate that in order to avoid any kind of risk during electrosurgical procedures on fetuses, the electrode must be placed at least 0.5 cm from delicate tissues. Copyright © 2007 John Wiley & Sons, Ltd.
Age‐specific risk of fetal loss post second trimester amniocentesis: analysis of 5043 cases
Authors: Mazza Vincenzo , Pati Mariangela , Bertucci Emma , Re Claudia , Ranzi Andrea , Percesepe Antonio , Forabosco Antonino , Volpe Annibale 
Published: January 2007

AbstractObjectivesTo assess the risk of fetal loss attributable to second trimester amniocentesis in singleton pregnancies through a cross‐sectional study.MethodsRecords of 5043 consecutive second trimester amniocentesis, performed by a single operator between 1997 and 2003, were analyzed. Fetal loss post amniocentesis was calculated by grouping pregnant women in age classes and assessing observed/expected (O/E) rate.ResultsTotal fetal losses were 40 (0.81%): 33 cases (0.67%) occurred before the 24th week, 37 cases (0.76%) before the 28th gestational week, and 3 cases (0.06%) after the 28th week of pregnancy. An age‐dependent increase of the rate of fetal loss, not statistically significant (Chi‐Square = 0.349, p = 0.505) was observed. The total O/E ratio values did not show any statistically significant risk (O/E ratio = 1.25, CI = 0.86–1.64). The analysis of the single age classes did not detect any statistical significance. The excess fetal loss rate associated with amniocentesis was 0.16%.ConclusionsNo effect of the 2nd trimester amniocentesis was noted on fetal loss. Copyright © 2007 John Wiley & Sons, Ltd.
Specific osseous spurs in a lethal form of hypophosphatasia correlated with 3D prenatal ultrasonographic images
Authors: Sinico M. , Levaillant J. M. , Vergnaud A. , Blondeau J. R. , Encha‐Razavi F. , Mornet E. , Le Merrer M. , Gerard‐Blanluet M. 
Published: January 2007

AbstractBackgroundHypophosphatasia is an osseous dysplasia with highly variable clinical expression, ranging from a recessive lethal prenatal type to late onset dominant short stature with premature shedding of teeth. Lethal forms of hypophosphatasia include short limb dwarfism with lack of ossification, especially on the vertebral bodies, very slender ribs and clavicles, and bowed, short lower extremities, with a bifid aspect of the diaphyses. Alkaline phosphatase is abnormally low in liver, bone, kidney and plasma.MethodsWe present here the prenatal images of a lethal form of hypophosphatasia, diagnosed precociously because of specific osseous spurs in a context of recurrent short limb dwarfism.ResultsPrenatal 3D ultrasonography has shown these spurs as early as 18 weeks. Molecular biology found compound heterozygous mutations in the gene TNSALP.ConclusionIn a context of short limb dwarfism, the search for these specific osseous spurs orient strongly toward the diagnosis of lethal hypophosphatasia. Copyright © 2007 John Wiley & Sons, Ltd.
Gold Coating of Poly(ethylene terephthalate) Modified by Argon Plasma
Authors: Kotál Vladimír , Švorčík Václav , Slepička Petr , Sajdl Petr , Bláhová Olga , Šutta Pavol , Hnatowicz Vladimír 
Published: January 2007

AbstractLittle information has been published concerning the interaction of gold with polymers. In the context of this lack of information, we decided to investigate the effect of Ar plasma treatment on the surface properties of poly(ethylene terephthalate) (PET) in order to examine its possible application for metal‐polymer adhesion improvement. The plasma treatment leads to an immediate increase of the PET's surface wettability, which however significantly depends on the sample aging, more specifically on the time elapsed after the treatment. X‐ray photoelectron spectroscopy (XPS) measurements revealed that the oxygen concentration in the surface‐near layers increases as a result of the treatment, but that it also changes with time for the samples in contact with the atmosphere, probably as a result of polar group rearrangements. Plasma initiated ablation and Au sputtering increases the surface roughness. The nanoindenter measurements revealed that the treatment increases the microhardness of treated PET. Contrary to hardness, the elastic modulus decreases. Scratch tests showed that the deformation of samples consisting of Au coatings deposited on both pristine and treated PET was elastic rather than plastic. We conclude from the nanoindenter data that the plasma modification does not affect the adhesion of gold on PET, but the X‐ray diffractometry (XRD) analysis showed that the Au film deposited on the as‐treated PET, and on PET aged for 14 d are the most stable.magnified image
Two‐Dimensional Simulation of Nanoassembly Precursor Species in Ar+H2+C2H2 Reactive Plasmas
Authors: Ostrikov Kostya (Ken) , Yoon Hyun‐Jin , Rider Amanda E. , Vladimirov Sergey V. 
Published: January 2007

AbstractThe results of two‐dimensional fluid simulation of number densities and fluxes of the main building blocks and surface preparation species involved in nanoassembly of carbon‐based nanopatterns in Ar+H2+C2H2 reactive plasmas are reported. It is shown that the process parameters and non‐uniformity of surface fluxes of each particular species may affect the targeted nanopattern quality. The results can be used to improve predictability of plasma‐aided nanofabrication processes and optimize the parameters of plasma nanotools.magnified image
On‐Wafer Tunable Deposition Rates Using Ionized Physical Vapor Deposition
Authors: Mao Daisheng , Wang Li‐Peng , Hopwood Jeffrey 
Published: January 2007

AbstractThe selective deposition of vapor‐phase metal ions is investigated using differential, on‐wafer biasing of microstructures. In this work, metal ions are generated by sputtering titanium atoms into an inductively coupled argon plasma, producing 50–80% ionization of the titanium flux to the wafer. The plasma sheath region surrounding the microstructures is modified by applying a pulsed DC bias to some of the microstructures such that plasma ions are attracted toward the most negative regions. Enhanced deposition is observed if the negative bias does not cause the impinging ion energy to exceed the sputtering threshold. Reduction of the deposition rate is observed on individual microstructures that are biased above the sputtering threshold due to resputtering of the titanium thin film by argon ions. A simple model is developed to confirm the mechanism of ion focusing, and the model also shows enhanced and then decreased net deposition rates as the ion energy increases.magnified image
Bacterial Deactivation Using a Low Temperature Argon Atmospheric Plasma Brush with Oxygen Addition
Authors: Huang Chun , Yu Qingsong , Hsieh Fu‐hung , Duan Yixiang 
Published: January 2007

AbstractThis study investigated the bacterial deactivation effects of a low temperature atmospheric argon plasma brush with oxygen addition. Two types of bacteria, Escherichia coli (E. coli) and Micrococcus luteus (M. luteus) seeded in various media were exposed to the oxygen enriched gas plasma and their survivability were thoroughly examined under various plasma conditions. It was found that the bacterial deactivation capability of the plasmas was highly dependent on the amount of oxygen addition and the type of supporting medium. With filter paper as the supporting medium, the addition of oxygen into the argon plasma system led to significant improvement in the bacterial killing efficacy, compared with an argon only plasma discharge. With oxygen addition, the plasma treatment time for a complete kill of the bacteria was 2 min for E. coli and 1 min for M. luteus. These are much shorter than the times required with argon only plasmas. When a nutrient broth or standard methods agar were used as the supporting medium, however, a longer plasma treatment time was necessary when using plasmas with the oxygen addition. The changes in bacterial cell structure after plasma exposure were examined using scanning electron microscopy. The change in plasma characteristics with oxygen addition was investigated using optical emission spectroscopy. The possible mechanism for bacterial inactivation of the plasmas is also discussed here.
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A novel tumor‐related protein, C7orf24, identified by proteome differential display of bladder urothelial carcinoma
Authors: Kageyama Susumu , Iwaki Hideaki , Inoue Hirokazu , Isono Takahiro , Yuasa Takeshi , Nogawa Masaki , Maekawa Taira , Ueda Masamichi , Kajita Yoichiro , Ogawa Osamu , Toguchida Junya , Yoshiki Tatsuhiro 
Published: January 2007

AbstractProteome analysis of bladder cancer with narrow‐range pH 2‐DE has identified a novel protein on chromosome 7 encoded by ORF 24 (C7orf24) as one of the highly expressed proteins in cancer cells. C7orf24 is currently registered in the protein database as a hypothetical protein with unknown function. The homologs of C7orf24 in other animals have also been registered as putative protein genes. Western blot analysis using a mAb against C7orf24 confirmed its higher expression in bladder cancer compared with normal tissue. Several other cancer cell lines were also found to express C7orf24. However, the introduction of C7orf24 into Rat‐1 or NIH3T3 cells did not cause malignant transformation. A stable transfectant of NIH3T3 cells with recombinant retrovirus vector was produced for a growth rate assay, and a higher growth rate was observed in C7orf24‐expressing cells compared with the controls. Six kinds of small interfering RNAs (siRNAs) were then produced, and C7orf24‐siRNA#5 showed a strong knockdown effect on protein expression and significant antiproliferative effects on cancer cell lines were demonstrated by the MTT assay. Therefore, C7orf24 may have an important role in cancer cell proliferation, and may be an appropriate therapeutic target molecule against cancer.
Proteomic analysis of autoantigens associated with systemic lupus erythematosus: Anti‐aldolase A antibody as a potential marker of lupus nephritis
Authors: Serada Satoshi , Fujimoto Minoru , Takahashi Tsuyoshi , He Ping , Hayashi Akio , Tanaka Toshio , Hagihara Keisuke , Yamadori Tomoki , Mochizuki Masao , Norioka Naoko , Norioka Shigemi , Kawase Ichiro , Naka Tetsuji 
Published: January 2007

AbstractTo screen for autoantibodies associated with systemic lupus erythematosus (SLE), we used proteomic approaches combining 2‐D PAGE and Western blot analysis, followed by protein identification by LC‐MS/MS analysis, resulting in the identification of aldolase A as a novel autoantigen in SLE. ELISA showed the prevalence of anti‐aldolase A antibodies to be 29.3% in SLE, 8.2% in rheumatoid arthritis, 18.1% in polymyositis and absent in healthy controls. Furthermore, 43.4% of SLE patients suffering from nephritis showed anti‐aldolase A autoantibodies, which was significantly higher than the prevalence for those without nephritis (11.1%). In lupus nephritis, there are few reliable diagnostic methods, other than urinalysis. Therefore, these results indicate that autoantibodies against aldolase A may serve as an alternative clinical biomarker of SLE associated with nephritis.
A method for the selective isolation and enrichment of carrier protein‐bound low‐molecular weight proteins and peptides in the blood
Authors: Camerini Serena , Polci Maria Letizia , Liotta Lance A. , Petricoin Emanuel F. , Zhou Weidong 
Published: January 2007

AbstractThe low molecular weight (LMW) region of the circulatory proteome, thought to contain a rich source of biomarkers, resides in vivo, in a complexed state with larger, highly abundant resident proteins. Consequently, serum fractionation approaches that deplete the high‐abundance proteins under native conditions will remove much of the LMW proteome. We describe a new strategy to systematically collect, isolate and enrich the LMW molecules that would be otherwise eliminated during the depletion of high‐abundance circulatory proteins based on continuous elution electrophoresis. We employ strong denaturing conditions to disrupt association with the high‐abundance carrier proteins followed by fractionation and removal of SDS. Under denaturation, the LMW molecules were effectively stripped from the highly abundant carrier proteins. We then removed the SDS by ion exchange matrix sequestration and concentrated the fractions. The outcome is a series of SDS‐free fractions of LMW molecules. The isolated fractions were then analyzed by enzymatic digestion followed by LC‐MS/MS analysis. The yield of multiple peptide hits as well as the total number of identifications significantly increased (50%) compared to unfractionated serum. The method yielded a 30% higher number of low‐abundance serum proteins compared to direct sequencing of unfractionated serum.
Computational design and crystal structure of an enhanced affinity mutant human CD8 αα coreceptor
Authors: Cole David K. , Rizkallah Pierre J. , Boulter Jonathan M. , Sami Malkit , Vuidepot Anne‐lise , Glick Meir , Gao Feng , Bell John I. , Jakobsen Bent K. , Gao George F. 
Published: January 2007

AbstractHuman CD8 is a T cell coreceptor, which binds to pHLA I and plays a pivotal role in the activation of cytotoxic T lymphocytes. Soluble recombinant CD8 αα has been shown to antagonize T cell activation, both in vitro and in vivo. However, because of a very low affinity for pHLA I, high concentrations of soluble CD8 αα are required for efficient inhibition. Based upon our knowledge of the wild‐type CD8/pHLA I structure, we have designed and produced a mutated form of soluble CD8 αα that binds to pHLA I with approximately fourfold higher affinity. We have characterized the binding of the high affinity CD8 mutant using surface plasmon resonance and determined its structure at 2.1 Å resolution using X‐ray crystallography. The analysis of this structure suggests that the higher affinity is achieved by providing a larger side chain that allows for an optimal contact to be made between the HLA α3 loop and the mutated CDR‐like loops of CD8. Proteins 2007. © 2007 Wiley‐Liss, Inc.