bluuebunny/crossref_metadata_2025_split huggingface dataset:
Valvular heart disease in Parkinson's disease patients treated with dopamine agonists: A reader‐blinded monocenter echocardiography study
Authors: Junghanns Susann , Fuhrmann Joerg T. , Simonis Gregor , Oelwein Christian , Koch Rainer , Strasser Ruth H. , Reichmann Heinz , Storch Alexander 
Published: November 2006

AbstractFibrotic valvular heart disease (VHD) has been reported in association with ergot dopamine agonists (DAs), but the current database is insufficient regarding clinical relevance and comparison to data on non‐ergot DAs. We evaluated the effects of four DAs (pergolide, cabergoline, ropinirole, pramipexole) on morphology and function of heart valves in patients with Parkinson's disease (PD) to determine the frequency and clinical relevance of DA‐induced VHD. A total of 85 patients treated with ergot or non‐ergot DAs and 38 age‐matched controls were evaluated by transthoracic echocardiography. Valvular pathology was assessed by established criteria of valvular regurgitation and a VHD scoring system. Both grading systems revealed increased frequency of VHD in ergot DA patients compared to both non‐ergot DA patients and controls with 22% of ergot DA patients having moderate VHD versus 3% of non‐ergot DA patients and none of controls (P = 0.001). We did not find correlations of echocardiographic findings with duration/cumulative dose of treatment, age, or vascular risk factors. Our data suggest that ergot DAs are associated with higher prevalence of VHD compared to non‐ergot DAs and controls. Standard echocardiography seems sufficient to detect VHD in PD patients treated with DAs. © 2006 Movement Disorder Society
Expression of insulin‐like growth factors systems in cloned cattle dead within hours after birth
Authors: Li Shijie , Li Yanxin , Yu Shuyang , Du Weihua , Zhang Lei , Dai Yunping , Liu Ying , Li Ning 
Published: November 2006

AbstractCloning by somatic nuclear transfer is an inefficient process in which many of the cloned animals die shortly after birth and display organ abnormalities. In an effort to determine the possible roles IGFs played in neonatal death and organ abnormalities, we have examined expression patterns of eight genes in insulin‐like growth factor (IGF) systems (IGF1, IGF2, IGF1R, IGF2R, IGFBP‐1, IGFBP‐2, IGFBP‐3, and IGFBP‐4) in six organs (heart, liver, spleen, lung, kidney, and brain) of both neonatal death cloned bovines (n = 9) and normal control calves (n = 3) produced by artificial insemination (AI) using real‐time quantitative RT‐PCR. The effect of the age of the fibroblast donor cell on the gene expression profiles was also investigated. Aberrant expressions of six genes (IGF2, IGF1R, IGF2R, IGFBP‐2, IGFBP‐3, and IGFBP‐4) were found in some studied tissues, but the expression of two genes (IGF1 and IGFBP‐1) had similar levels with the normal controls. For the studied genes, kidney was the organ that was most affected (five genes) by gene downregulation, whereas spleen was the organ that was not affected. The two upregulation genes were in brain, but both of downregulation and upregulation were found in the heart, liver, and lung. The expression of three genes (IGF2R, IGFBP‐4, and IGF2) in some tissues showed significant differences between AF cell‐derived and FF cell‐derived clones. Our results suggest that aberrations in gene expression within IGF systems were found in most cloned bovine tissues of neonatal death. Because IGF systems play an important role in embryo development and organogenesis, the aberrant transcription patterns detected in these clones may contribute to the defects of organs reported in neonatal death of clones. Mol. Reprod. Dev. 74: 397–402, 2007. © 2006 Wiley‐Liss, Inc.
Signal‐to‐noise ratio and spectral linewidth improvements between 1.5 and 7 Tesla in proton echo‐planar spectroscopic imaging
Authors: Otazo Ricardo , Mueller Bryon , Ugurbil Kamil , Wald Lawrence , Posse Stefan 
Published: November 2006

AbstractThis study characterizes gains in sensitivity and spectral resolution of proton echo‐planar spectroscopic imaging (PEPSI) with increasing magnetic field strength (B0). Signal‐to‐noise ratio (SNR) per unit volume and unit time, and intrinsic linewidth (LW) of N‐acetyl‐aspartate (NAA), creatine (Cr), and choline (Cho) were measured with PEPSI at 1.5, 3, 4, and 7 Tesla on scanners that shared a similar software and hardware platform, using circularly polarized (CP) and eight‐channel phased‐array (PA) head coils. Data were corrected for relaxation effects and processed with a time‐domain matched filter (MF) adapted to each B0. The SNR and LW measured with PEPSI were very similar to those measured with conventional point‐resolved spectroscopy (PRESS) SI. Measurements with the CP coil demonstrated a nearly linear SNR gain with respect to B0 in central brain regions. For the PA coil, the SNR–B0 relationship was less than linear, but there was a substantial SNR increase in comparison to the CP coil. The LW in units of ppm decreased with B0, resulting in improved spectral resolution. These studies using PEPSI demonstrated linear gains in SNR with respect to B0, consistent with theoretical expectations, and a decrease in ppm LW with increasing B0. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Quantified sensory abnormalities in early genetically verified transthyretin amyloid polyneuropathy
Authors: Heldestad Victoria , Nordh Erik 
Published: November 2006

AbstractTransthyretin amyloid neuropathy of type 1 (Swedish–Portuguese type) is an autosomally inherited progressive disease with a Val30Met mutation, causing generalized sensory‐motor polyneuropathy. Quantitative sensory testing (QST) quantifies thermal threshold changes in patients with manifest general polyneuropathy, but its applicability at an early clinical stage of a strict biochemically defined disease has not yet been shown. Thermal QST was performed in 23 patients having a positive Val30Met marker and clinical symptoms of peripheral small‐fiber neuropathy but normal electrophysiological findings and compared to a reference group of 43 healthy volunteers, both subdivided into age groups ≤45 and >45 years. Significant differences between patients and controls were found at all test sites in both age groups, except for warm thresholds at the medial lower leg in those >45 years. QST thus demonstrated elevated thermal thresholds before the development of electrophysiological abnormalities, which indicate large‐fiber involvement. These findings confirm that QST is a useful method for documentation of developing polyneuropathy. Muscle Nerve, 2006
Safety of nerve conduction studies in patients with implanted cardiac devices
Authors: Schoeck Andreas P. , Mellion Michelle L. , Gilchrist James M. , Christian Fredric V. 
Published: November 2006

AbstractPatients with implanted cardiac devices and their physicians may defer important electrodiagnostic testing because of anxiety about potential negative effects on the device. To determine the safety of routine nerve conduction studies (NCS) in this population, 10 patients with permanent dual‐chamber pacemakers of various types and five patients with implanted cardiac defibrillators (ICD) underwent nerve stimulation at sites commonly used during NCS. The implanted cardiac device was interrogated before and after the study and there was continuous monitoring of the surface electrocardiogram (ECG) and atrial and ventricular electrograms. Electrical impulses generated during routine NCS were never detected by the sensing amplifier and did not affect the programmed settings of the implanted cardiac device. We conclude that routine NCS is safe in patients with implanted cardiac pacemakers with bipolar sensing configurations and defibrillators. Muscle Nerve, 2006
Effects of hyperbaric exposure with high oxygen concentration on glucose and insulin levels and skeletal muscle‐fiber properties in diabetic rats
Authors: Yasuda Koichiro , Adachi Tetsuya , Gu Ning , Matsumoto Akiko , Matsunaga Tetsuro , Tsujimoto Gozoh , Tsuda Kinsuke , Ishihara Akihiko 
Published: November 2006

AbstractThe effects of hyperbaric exposure with high oxygen concentration on glucose and insulin levels and skeletal muscle‐fiber properties were investigated in type 2 diabetic Goto‐Kakizaki rats. Five‐week‐old rats were exposed to a hyperbaric environment (1.25 atmospheric pressure) with a high oxygen concentration (36%) for 6 h daily. Glucose and insulin levels and properties including fiber‐type distribution, cross‐sectional area, and oxidative enzyme activity in the soleus muscle were examined after hyperbaric exposure for 4 weeks. The growth‐related increase in glucose level was inhibited by hyperbaric exposure, and insulin also showed lower levels compared with control rats. The percentage of low‐oxidative type I fibers in the muscle decreased and high‐oxidative type IIA and type IIC fibers, which were not detected in the muscle of control rats, were observed after hyperbaric exposure. The oxidative enzyme activity of type I fibers in the muscle increased after hyperbaric exposure. Hyperbaric exposure with high oxygen concentration might therefore provide a new approach to improve the glucose tolerance, insulin resistance, and altered skeletal muscle metabolism that are caused by diabetes mellitus. Muscle Nerve, 2006
Investigation of melt manipulation phenomena during injection molding via in situ birefringence observation
Authors: Angstadt David C. , Coulter John P. 
Published: November 2006

AbstractThis study investigates the effects of melt manipulation on the development of molecular orientation during injection molding processing. Vibration‐assisted injection molding (VAIM), a particular method of melt manipulation, is a variation of conventional injection molding in which oscillatory energy is imparted to the polymer melt by vibrating the injection screw axially during the injection and packing stages of the molding cycle. Previous studies have shown that this process positively affects the tensile strength of polystyrene parts, but that the magnitude of the increase is dependent upon the processing parameters. Observation of birefringence patterns in VAIM processed samples show a significant impact on molecular orientation. A specially designed mold and associated image capture system has been developed and is used in this study to record the birefringence patterns of the polymer melt within the cavity during processing. Observation of birefringence shows that orientation develops primarily during post‐vibration packing of the part and not during the vibration phase as previously thought. The observed effects of process parameters such as melt temperature, packing pressure, and vibration duration are discussed. POLYM. ENG. SCI. 46:1691–1697, 2006. © 2006 Society of Plastics Engineers
Radical mediated graft modification of polyolefins: Vinyltriethoxysilane addition dynamics and yields
Authors: Parent J. Scott , Parodi Renzo , Wu Wei 
Published: November 2006

AbstractThe dynamics and yields of peroxide‐initiated grafting of vinyltriethoxysilane (VTEOS) to tetradecane and linear low density polyethylene (LLDPE) are described. VTEOS grafting kinetics at 160°C abide by the basic tenets of radical‐mediated additions in terms of the influence of initiator loading and homolysis rate. However, reaction yields recorded for both the model and polymer systems are surprisingly insensitive to temperature, in apparent conflict with conventional models of free radical addition chemistry. These experimental observations are used to identify the predominant reactions within a general kinetic scheme, and to support the assumptions required to develop a rate expression that captures the effect of reagent concentrations on the dynamics of graft‐modification. POLYM. ENG. SCI. 46:1754–1761, 2006. © 2006 Society of Plastics Engineers.
Interfacial characteristics of film insert molded polycarbonate film/polycarbonate‐acrylonitrile‐butadiene‐styrene substrate, part 1: Influence of substrate molecular weight and film thickness
Authors: Leong Y.W. , Ishiaku U.S. , Kotaki M. , Hamada H. , Yamaguchi S. 
Published: November 2006

AbstractAdhesion properties between a polycarbonate (PC)/acrylonitrile‐butadiene‐styrene blend substrate and PC films of various thicknesses, bonded through film insert molding, were investigated. The use of various molecular weights of PC and incorporation of PC‐oligomer in the blend substrate has been found to severely affect the adhesion strength and alter the delamination characteristics at the film–substrate interface. Thicker films were able to increase film–substrate adhesion, apart from providing added impact resistance to a brittle substrate. Polym. Eng. Sci. 46:1674–1683, 2006. © 2006 Society of Plastics Engineers
Comparison of the effect of epoxy microspheres on the thermomechanical and rheological properties of an epoxy resin system
Authors: Ambrogi Veronica , Cosco Simona , Carfagna Cosimo , Cicala Gianluca , Oliveri Ludovica , Recca Antonio 
Published: November 2006

AbstractThe rheological and thermomechanical behaviors of toughened epoxy resins filled with thermosetting microsized spherical particles were investigated. Two epoxy systems were used to prepare microspheres: a Bisphenol A‐type resin (EPON825) cured with 2,4‐diaminotoluene and a Bisphenol F‐based epoxy resin (PY306) crosslinked with diethyltoluenediamine. Both systems of microspheres were synthesized through dispersion polymerization and differed to each other in size, as evidenced by morphological analysis. These microparticles were blended, in different weight percents (10 and 20 wt%), with a matrix consisting of diglycidyl ether of Bisphenol A (EPON828) and 3,3′‐diaminodiphenylsulphone (3,3′DDS). Rheological behavior of the prepared blends was preliminarily studied. After cure, the dynamic‐mechanical properties of the composites were also investigated. Results indicated that the reactivity of the uncured blends, as well as the viscoelastic properties of crosslinked systems, are influenced not only by the nature and the amount of the microparticles introduced, but also, in a significant way, by their size. POLYM. ENG. SCI. 46:1739–1747, 2006. © 2006 Society of Plastics Engineers.
Poly(glycoamidoamine)s: Cationic glycopolymers for DNA delivery
Authors: Reineke Theresa M. 
Published: November 2006

AbstractPolymer science is playing an exciting role in inspiring and advancing novel discoveries in the area of genetic drug delivery. Polymeric materials can be synthesized and chemically tailored to bind and compact nucleic acids into viral‐like nanoparticles termed polyplexes that can deliver genetic materials into cells. This article highlights our work in this area to synthesize and study a novel class of cationic glycopolymers that we have termed poly(glycoamidoamine)s (PGAAs). The design of these materials has been inspired by many previous works in the literature. Carbohydrate comonomers have been incorporated into these structures to lower the toxicity of the delivery vehicle, and oligoamine moieties have been added to yield a cationic backbone that facilitates strong DNA binding, compaction, cellular uptake, and delivery of genetic material. PGAAs have been designed to vary in the carbohydrate size, the hydroxyl number and stereochemistry, the amine number, and the presence or absence of heterocyclic groups. Through structure–bioactivity studies, we have discovered that these materials are highly biocompatible, and each specific feature plays a large role in the observed delivery efficacy. Such structure–property studies are important for increasing our understanding of how the polymer chemistry affects the biological activity for the clinical development of polymer‐based therapeutics. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6895–6908, 2006
Melting of solvents nanoconfined by polymers and networks
Authors: Qin Qian , McKenna Gregory B. 
Published: November 2006

AbstractThermoporosimetry is becoming increasingly used to study nanoscale heterogeneity and structure in polymer networks. The starting point for thermoporosimetry is the Gibbs‐Thomson (GT) relation between melting point and inverse crystal size. In the case of polymers, the Flory‐Huggins (FH) model also predicts that there is a depression of the melting point because of the mixing of the polymer and the solvent molecules, and this needs to be taken into account. The first step in analysis of size heterogeneity using thermoporosimetry and the GT equation requires that there be quantitative agreement between the FH theory and the melting points of the diluent in the uncrosslinked rubber. We find that both benzene and hexadecane exhibit excessive melting point depressions in uncrosslinked polyisoprene. This may imply that the uncrosslinked polymer is divided into ‘nanoheterogeneities’. We further find that the heat of fusion decreases as polymer concentration increases for the benzene, but not for the hexadecane. Finally, we compare pore size distributions obtained for a crosslinked polyisoprene as determined from the melting behavior ofn‐hexadecane as a diluent, using different references for how the uncrosslinked polymer behaves. While number average distribution is not very different between the different analyses, the weight average distribution is. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3475–3486, 2006
A quantum mechanics/molecular mechanics study of the reaction mechanism of the hepatitis C virus NS3 protease with the NS5A/5B substrate
Authors: Oliva Carolina , Rodríguez Alejandro , González Miguel , Yang Wei 
Published: November 2006

AbstractCombined quantum mechanics and molecular mechanics (QM/MM) calculations were carried out to characterize the reaction mechanism of the NS3 protease with its preferred substrate (NS5A/5B). The main purpose of this study was to locate the barrier states and intermediates along the distinguished coordinate path (DCP) involved in this process. These structures, and in particular the one corresponding to the first barrier state and intermediate (B1 and I1), could be a starting point for the synthesis of inhibitors of this protease, which could be used to treat hepatitis C. The two first steps of the reaction mechanism were studied, i.e., the acylation step and the breaking of the peptide bond. The first step takes place through a tetracoordinated intermediate, as suggested from previous works on other Serine proteases. The importance of the different amino acid residues was also considered (perturbation study where the MM charges of each residue were set to zero independently). The residues of the oxyanion hole were confirmed as the most important for the electrostatic stabilization of the tetracoordinate intermediate. Moreover, the role of other residues, e.g., Arg‐155 and Asp‐79, was also explained. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Ferromagnetism in epitaxial Zn0.95Co0.05O films grown on ZnO and Al2O3
Authors: Nielsen K. , Bauer S. , Lübbe M. , Goennenwein S. T. B. , Opel M. , Simon J. , Mader W. , Gross R. 
Published: November 2006

AbstractIn this article, the possible mechanisms resulting in strong ferromagnetic coupling in transition metal(TM)‐doped ZnO and other diluted magnetic semiconductors (DMS) are reviewed and the prerequisites for the observation of room temperature ferromagnetism in TM‐doped ZnO are defined. In order to study the ferromagnetic behavior we have grown epitaxial Zn0.95Co0.05O films simultaneously on (0001) ZnO and Al2O3substrates by laser molecular beam epitaxy at different deposition temperatures. A systematic study of the structural and magnetic properties has been performed to reveal their interdependence. Room temperature ferromagnetism has been found in Zn0.95Co0.05O films grown on ZnO, whereas for films deposited on sapphire only weak ferromagnetic signals have been detected which could not unambiguously be separated from those of the substrate. The different behavior is explained by different structural properties and defect densities in both films. Our experimental findings are in good agreement with a spin split impurity band model, where strong ferromagnetic exchange in ZnO:Co2+is obtained by a strong hybridization between the magnetic Co2+ion states and the donor states due to a large density of native defects. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum cascade lasers: The semiconductor solution for lasers in the mid‐ and far‐infrared spectral regions
Authors: Sirtori Carlo , Dhillon Sukhdeep , Faugeras Clement , Vasanelli A. , Marcadet Xavier 
Published: November 2006

AbstractThe quantum cascade laser is a semiconductor light source based on resonant tunnelling and optical transitions between quantised conduction band states. In these devices the principles of operation are not re lated to the physical properties of the constituent materials, but arise from an artificial potential designed using a sequence of very thin layers of different semiconductor materials. The quantum design implemented by highly sophisticated epitaxial growth, allows one to ascribe in semiconductor crystals this artificial potential with the desired electronic energy levels and wavefunctions. In recent years the performance of these devices has improved markedly and this semiconductor technology is now an attractive choice for the fabrication of mid‐far infrared lasers in a very wide spectral range (3.5–160 µm). At present, the best performances are obtained at wavelengths between 5–12 µm, where continuous‐wave room temperature operation is routinely achieved and record average power in the order of 1 W has been demonstrated. The long wavelength region has been only recently explored and lasers operating temperatures do not currently exceed 150 K. Interesting nonlinear mixing of diode lasers with a THz laser has been recently demonstrated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oligonucleotide hybridization monitored by surface plasmon enhanced fluorescence spectroscopy with bio‐conjugated core/shell quantum dots. Influence of luminescence blinking
Authors: Robelek R. , Stefani F. D. , Knoll W. 
Published: November 2006

AbstractThe influence of the luminescence blinking of quantum dots on kinetic bio‐sensing measurements is investigated. The hybridization kinetics of labelled DNA sequences with surface‐immobilized DNA probes using surface plasmon enhanced fluorescence spectroscopy is employed to compare the behaviour of quantum‐dot‐ and organic‐chromophore‐labelled DNA targets. The presented experiments show that quantum‐dot labelled targets present apparent complex adsorption kinetics that can lead to inaccurate conclusions. By means of single quantum dot luminescence measurements and Monte‐Carlo simulations, it is demonstrated that the anomalous adsorption kinetics observed with the quantum‐dot labelled targets can be accounted for by the luminescence blinking statistics of the quantum dots. Thus, special attention should be paid when applying quantum dots as fluorescent labels in bio affinity studies in order to avoid wrong interpretations due to the special photo physical behaviour of these semiconducting nanocrystals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)