bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomistic models of three fluorinated polyimides in the amorphous state
Authors: Pandiyan S. , Brown D. , van der Vegt N. F. A. , Neyertz S. 
Published: May 2009

AbstractMolecular models of three fluorinated polyimides based on the 4,4′‐(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) have been studied using molecular dynamics (MD) simulations. The respective diamines were 4,4′‐hexafluoroisopropylidene dianiline (6FpDA), 3,3′‐hexafluoroisopropylidene dianiline (6FmDA), and 2,4,6‐trimethyl‐1,3phenylenediamine (DAM). Thirty independent samples were prepared using a hybrid pivot Monte Carlo‐MD generation technique and average densities were found to be in very good agreement with experiment. Model structures also agreed with available wide‐angle X‐ray scattering data. Cohesive energies, Hildebrand solubility parameters, fractional free volumes (FFV), void space distributions and intermolecular as well as intramolecular interactions were analyzed. The differences in bulk properties between both 6FDA‐6FpDA and 6FDA‐6FmDA isomers remain fairly small, although the configurations of the former are more extended. 6FDA‐DAM has a lower density, larger intermolecular distances, and higher free volume than the other two polyimides. Results are discussed with respect to their use as matrices for gas separation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1166–1180, 2009
Pattern formation in PMMA film induced by electric field
Authors: Lyutakov Oleksiy , Hüttel Ivan , Prajzler Václav , Jeřábek Vítězslav , Jančárek Alexander , Hnatowicz Vladimír , Švorčík Václav 
Published: May 2009

AbstractMicro‐sized patterns were created on thin poly(methyl methacrylate) (PMMA) films by the effect of external field, perpendicular to the film surface. The PMMA film, prepared by spin‐coating onto Si wafer, was heated to the fluid temperature (275 °C) and a linear pattern was created by the effect of electric field produced by a strip electrode. In another experiment, a round pattern was created as a result of local laser heating of the PMMA film under homogenous electrical field. The created patterns were analyzed by optical microscopy and profile meter. The dependence of the form and size of the created patterns on the intensity of the electric field, exposure time, and initial film thickness was examined. Wave guiding property of a linear pattern, produced by the above technique, was examined in a simple experiment. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1131–1135, 2009
Circuit simulation for the dielectric responses of the composites of copper phthalocyanine oligomers and sulfonated polyurethanes by separating the structural elements
Authors: Zhang Juan , Zhu Dan , Matsuo Masaru 
Published: May 2009

AbstractThe copper phthalocyanine (CuPc) oligomer with high dielectric constant was synthesized by the solution method. The FT‐IR and X‐ray diffraction results revealed its chemical structure. The high dielectric constant of CuPc was proved to result from the free movement of charge carriers along the conjugated orbitals. The composites of CuPc and sulfonated polyurethane (PUI) were prepared and the contents of CuPc in the composites were varied from 10 to 50 wt %. The dielectric performance was greatly enhanced for the composite compared with that of average polymers. Different from the behaviors appeared in a common composite with conductive fillers, there is no percolation phenomenon observed in the CuPc/PUI composite, and the dielectric constants of CuPc/PUI composites decreased with the increase in the CuPc content, which is assumed to due to the strong electrostatic interactions between CuPc and PUI. Considering the many‐body interactions within the bulk sample and the contact effect between the bulk sample and the metallic electrode, an equivalent circuit was established to simulate the dielectric behaviors of the composites and computational curve fitting was done. The results were in good agreement, indicating that the dielectric responses of the composites come from both the extrinsic and the intrinsic contributions. The extrinsic was associated with the Maxwell‐Wagner relaxation at the interface between the electrode and the bulk sample, and the intrinsic was associated with the huge dipoles provided by the mobile charges within the CuPc grains and the interaction among them in the bulk composites. A circuit model concerning the universal dielectric response was proposed in describing the intrinsic contribution, which quantitatively verified the strong interaction among the dipoles with the relaxation time, representing the aggregated structure of CuPc when its content was high in the composites. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1146–1155, 2009
Correlation study among oxygen permeability, molecular mobility, and amorphous structure change of poly(ethylene‐vinylalcohol copolymers) by moisture
Authors: Yamamoto Tomoyuki , Kanda Taiji , Nishihara Yuko , Ooshima Tetsuya , Saito Yoichiro 
Published: May 2009

AbstractOxygen permeability and the free‐volume hole size (cavity size) of ethylene‐vinylalcohol copolymers (EVOH) indicate abnormal humidity dependence, that is, they have minimum values in the range of around 20–40% RH, not showing a monotonic increase with humidity. To clarify this abnormal phenomenon, we investigated its molecular mobility and amorphous structure change by means of solid‐state NMR and temperature‐modulated differential scanning calorimetry (TMDSC). The glass transition temperature (Tg) decreased with humidity. Specimens stored at 15–60% RH showed large enthalpy relaxation, and it was found that the amorphous structure became more compact and the molecular conformation became more stable by ageing within this range of humidity. Under these conditions, solid‐state NMR measurement showed a component with intermediate relaxation time in the amorphous region. The results obtained by TMDSC and solid‐state NMR showed a reduction in molecular mobility by densifying in the amorphous region under the condition of 15–60% RH. The fact that the oxygen permeability and the cavity size of EVOH indicate minimum values at low humidity are attributed to the reduction in molecular mobility by enthalpy relaxation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1181–1191, 2009
Effect of PVDF characteristics on extruded film morphology and porous membranes feasibility by stretching
Authors: Sadeghi F. , Tabatabaei S. H. , Ajji A. , Carreau P. J. 
Published: May 2009

AbstractThree different polyvinylidene fluoride (PVDF) resins were selected to develop porous membranes through melt extrusion and stretching. The effect of the polymer rheology on chain elongation in the melt state was studied. The possibility of generating a row‐nucleated lamellar crystallization for precursor films was investigated. The arrangement and orientation of the crystalline phase were examined by wide angle X‐ray diffraction (WAXD) and Fourier Transform Infrared Spectroscopy (FTIR). The extrusion conditions and the blend compositions were adjusted to obtain uniform precursor films with appropriate morphology. Annealing, cold and hot stretching were consequently employed to generate and enlarge the pores. It was found that a proper crystalline structure of the precursor films was strongly dependent on molecular weight of PVDF and process conditions. Blending of two PVDF resins having low and high molecular weights improved the water vapor permeability of the obtained membranes. The tensile response was monitored during the stretching process for membrane development and the results revealed a distinct behavior for the membranes having low or high permeability. The membranes with low permeability did not show any significant strain hardening during stretching whereas for highly permeable membranes, a noticeable strain hardening behavior was observed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1219–1229, 2009
Electronic structure and magnetic properties of Cu‐doped SnO2 from first‐principles study
Authors: Zhang Chang‐wen , Kao Hong , Dong Jian‐min , Li Ping 
Published: May 2009

AbstractWe have studied the electronic structure of Cu‐doped SnO2, with different possible geometrical sites for the Cu dopant, to determine the most favored magnetic properties. Our study shows that each Cu has spin‐polarized states in the band gap generating a magnetic moment 2.0μB. We also find Cu impurities tend to form clusters which induces strong ferromagnetism with high Curie temperature, through the same p–d hopping interactions as found in Sr2FeMoO6 [Phys. Rev. Lett. 85, 2549 (2000)]. Doped p‐type carriers enhanced the ferromagnetism, while n‐type carriers are detrimental to ferromagnetism due to charge compensating effects, indicating that the strong ferromagnetism in Cu‐doped SnO2 would be achieved by hole doping. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Locally Delivered Growth Factor Enhances the Angiogenic Efficacy of Adipose-Derived Stromal Cells Transplanted to Ischemic Limbs
Authors: Bhang Suk Ho , Cho Seung-Woo , Lim Jae Min , Kang Jin Muk , Lee Tae-Jin , Yang Hee Seok , Song Young Soo , Park Moon Hyang , Kim Hyo-Soo , Yoo Kyung-Jong , Jang Yangsoo , Langer Robert , Anderson Daniel G. , Kim Byung-Soo 
Published: May 2009

AbstractIschemia is a potentially fatal medical event that is associated with as many as 30% of all deaths. Stem cell therapy offers significant therapeutic promise, but poor survival following transplantation to ischemic tissue limits its efficacy. Here we demonstrate that nanosphere-mediated growth factor delivery can enhance the survival of transplanted human adipose-derived stromal cells (hADSCs) and secretion of human angiogenic growth factors per cell, and substantially improve therapeutic efficacy of hADSCs. In vitro, in hypoxic (1% oxygen) and serum-deprived conditions that simulate in vivo ischemia, fibroblast growth factor-2 (FGF2) significantly reduced hADSC apoptosis and enhanced angiogenic growth factor secretion. In vivo, hADSCs delivered intramuscularly into ischemic hind limbs in combination with FGF2 resulted in significant improvements in limb survival and blood perfusion, as well as survival of the transplanted hADSCs and secretion of human angiogenic growth factors (i.e., vascular endothelial growth factor, hepatocyte growth factor, and FGF2). Interestingly, the majority of transplanted hADSCs were localized adjacent to the microvessels rather than being incorporated into them, suggesting that their major contribution to angiogenesis might be to increase paracrine secretion of angiogenic growth factors. This study demonstrates the potential of hADSCs in combination with growth factors for use in the treatment of ischemia.Disclosure of potential conflicts of interest is found at the end of this article.
Generation of Pancreatic Hormone-Expressing Islet-Like Cell Aggregates from Murine Adipose Tissue-Derived Stem Cells
Authors: Chandra Vikash , G Swetha , Phadnis Smruti , Nair Prabha D. , Bhonde Ramesh R. 
Published: May 2009

Abstract
The success of cell replacement therapy for diabetes depends on the availability and generation of an adequate number of islets, preferably from an autologous origin. Stem cells are now being probed for the generation of physiologically competent, insulin-producing cells. In this investigation, we explored the potential of adipose tissue-derived stem cells (ASCs) to differentiate into pancreatic hormone-expressing islet-like cell aggregates (ICAs). We initiated ASC culture from epididymal fat pads of Swiss albino mice to obtain mesenchymal cells, murine epididymal (mE)-ASCs. Subsequent single-cell cloning resulted in a homogeneous cell population with a CD29+CD44+Sca-1+ surface antigen expression profile. We formulated a 10-day differentiation protocol to generate insulin-expressing ICAs from mE-ASCs by progressively changing the differentiation cocktail on day 1, day 3, and day 5. Our stage-specific approach successfully differentiated mesodermic mE-ASCs into definitive endoderm (cells expressing Sox17, Foxa2, GATA-4, and cytokeratin [CK]-19), then into pancreatic endoderm (cells expressing pancreatic and duodenal homeobox [PDX]-1, Ngn3, NeuroD, Pax4, and glucose transporter 2), and finally into cells expressing pancreatic hormones (insulin, glucagon, somatostatin). Fluorescence-activated cell sorting analysis showed that day 5 ICAs contained 64.84% ± 7.03% PDX-1+ cells, and in day 10 mature ICAs, 48.17% ± 3% of cells expressed C-peptide. Day 10 ICAs released C-peptide in a glucose-dependent manner, exhibiting in vitro functionality. Electron microscopy of day 10 ICAs revealed the presence of numerous secretory granules within the cell cytoplasm. Calcium alginate-encapsulated day 10 ICAs (1,000–1,200), when transplanted i.p. into streptozotocin-induced diabetic mice, restored normoglycemia within 2 weeks. The data presented here demonstrate the feasibility of using ASCs as a source of autologous stem cells to differentiate into the pancreatic lineage.
Disclosure of potential conflicts of interest is found at the end of this article.
Electrochemical oxidative formation of ordered monolayers of thiol molecules on Au(111) surface
Authors: Uosaki Kohei 
Published: May 2009

AbstractElectrochemical oxidative formation of thiolate monolayers on a Au(111) surface in KOH ethanol solutions of various thiol concentrations is described. The formation process was investigated by electrochemistry, in situ scanning tunneling microscopy (STM), and surface X‐ray diffraction (SXRD). The reductive charge in the linear sweep voltammogram after keeping the potential at +0.1 V increased with holding time and reached the saturated value of 103 µC cm−2, corresponding to the full monolayer coverage of the ($\sqrt{3}\times\sqrt{3}$) structure. The desorption peak shifted negatively with holding time even after the monolayer was formed, suggesting that ordering of the monolayer requires a much longer time than full coverage adsorption. The herringbone structure, corresponding to the ($\sqrt{3}\times 23$ × 23) structure, was observed on the Au(111) surface in KOH ethanol solution by in situ STM, which shows that a clean surface was exposed. When hexanethiol ethanol solution was added into the ethanol solution at −450 mV so that the final thiol concentration was higher than ca. 5 µM, generation of vacancy islands (VIs) was observed, which shows the potentiostatic monolayer formation. When the potential was scanned positively from −950 mV where a clean reconstructed Au(111) surface was exposed, generation of VIs was observed accompanied by anodic current flow. During both oxidative adsorption and reductive desorption of the monolayer, the shape of the steps of the gold surface changed drastically, which suggests that the gold atoms on the surface are extremely mobile during the monolayer formation. SXRD measurement confirmed the surface reconstruction lifting upon monolayer formation. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 199–209; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900002
Feasibility of Intraoperative Neuromonitoring During Thyroid Surgery After Administration of Nondepolarizing Neuromuscular Blocking Agents
Authors: Chu Koung‐Shing , Wu Sheng‐Hua , Lu I‐Cheng , Tsai Cheng‐Jing , Wu Che‐Wei , Kuo Wen‐Rei , Lee Ka‐Wo , Chiang Feng‐Yu 
Published: May 2009

AbstractBackgroundA short‐acting depolarizing neuromuscular blocking agent (NMBA), succinylcholine, has been utilized for thyroid operations with intraoperative neuromonitoring (IONM). Because of its potential to cause serious side effects, this prospective study tried to determine the feasibility of IONM after administration of a nondepolarizing NMBA during thyroid operations.MethodsComplete IONM data for 179 patients who had normal cord mobility were investigated: 90 patients received an induction dose of rocuronium (group R) and 89 received atracurium (group A). Electromyography signals were obtained from the vagus nerve before and after resection of the thyroid lobe and were defined as V1 and V2 signals, respectively. Accelerometry (percent twitch) was used to monitor the quantitative degree of neuromuscular blockade.ResultsV1 and V2 signals were obtained successfully in all patients. The percent twitch at the V1 signal was significantly lower than that at the V2 signal in both groups (39% ± 20% vs. 69% ± 26% in group R; 35% ± 28% vs. 56% ± 35 % in group A; both p < 0.01). However, the magnitude of the V1 and V2 signals did not differ significantly in either in group (473.8 ± 290.8 μV vs. 528 ± 316.2 μV in group R; 584.8 ± 394.3 μV vs. 637.8 ± 458.2 μV in group A; both p > 0.05).ConclusionsA single dose of either rocuronium or atracurium was feasible for IONM during thyroid surgery and provided adequate muscle relaxation for tracheal intubation.
Randomized Clinical Trial of Laparoscopic Versus Open Repair of the Perforated Peptic Ulcer: The LAMA Trial
Authors: Bertleff Mariëtta J. O. E. , Halm Jens A. , Bemelman Willem A. , van der Ham Arie C. , van der Harst Erwin , Oei Hok I. , Smulders J. F. , Steyerberg E. W. , Lange Johan F. 
Published: May 2009

AbstractBackgroundLaparoscopic surgery has become popular during the last decade, mainly because it is associated with fewer postoperative complications than the conventional open approach. It remains unclear, however, if this benefit is observed after laparoscopic correction of perforated peptic ulcer (PPU). The goal of the present study was to evaluate whether laparoscopic closure of a PPU is as safe as conventional open correction.MethodsThe study was based on a randomized controlled trial in which nine medical centers from the Netherlands participated. A total of 109 patients with symptoms of PPU and evidence of air under the diaphragm were scheduled to receive a PPU repair. After exclusion of 8 patients during the operation, outcomes were analyzed for laparotomy (n = 49) and for the laparoscopic procedure (n = 52).ResultsOperating time in the laparoscopy group was significantly longer than in the open group (75 min versus 50 min). Differences regarding postoperative dosage of opiates and the visual analog scale (VAS) for pain scoring system were in favor of the laparoscopic procedure. The VAS score on postoperative days 1, 3, and 7 was significant lower (P < 0.05) in the laparoscopic group. Complications were equally distributed. Hospital stay was also comparable: 6.5 days in the laparoscopic group versus 8.0 days in the open group (P = 0.235).ConclusionsLaparoscopic repair of PPU is a safe procedure compared with open repair. The results considering postoperative pain favor the laparoscopic procedure.
Appraising the Quality of Care in Surgery
Authors: Mayer Erik K. , Chow Andre , Vale Justin A. , Athanasiou Thanos 
Published: May 2009

AbstractThere is currently no validated measurement system available for quality of care assessment in surgery despite all of the inherent benefits of such an approach. A structured quality framework needs to be developed and incorporate measures that are truly reflective of several important dimensions of care within the entire treatment episode. Presently this has been only partially addressed. These measures of quality can be categorized into clinical pathway measures (structure of care, process of care, outcome of care, and economic measures of care) and patient‐reported measures (patient‐reported treatment outcomes, health‐related quality of life measures, and patient satisfaction). Combining these measures to create an overall composite quality score can be made feasible only if it is supported by the use of robust statistical methodology. It is important to use appropriate display of performance data to facilitate provider engagement in quality improvement initiatives. This article was designed to present such a structured approach of a quality framework, which is required to appraise the quality of care in surgery to enhance future quality improvement programmes.
Magnetic and Cytotoxicity Properties of La1−xSr
x
MnO3(0 ≤ x ≤ 0.5) Nanoparticles Prepared by a Simple Thermal Hydro-Decomposition
Authors: Daengsakul Sujittra , Thomas Chunpen , Thomas Ian , Mongkolkachit Charusporn , Siri Sineenat , Amornkitbamrung Vittaya , Maensiri Santi 
Published: May 2009

Abstract
This study reports the magnetic and cytotoxicity properties of magnetic nanoparticles of La1−x
Sr
x
MnO3(LSMO) withx = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 by a simple thermal decomposition method by using acetate salts of La, Sr, and Mn as starting materials in aqueous solution. To obtain the LSMO nanoparticles, thermal decomposition of the precursor was carried out at the temperatures of 600, 700, 800, and 900 °C for 6 h. The synthesized LSMO nanoparticles were characterized by XRD, FT-IR, TEM, and SEM. Structural characterization shows that the prepared particles consist of two phases of LaMnO3(LMO) and LSMO with crystallite sizes ranging from 20 nm to 87 nm. All the prepared samples have a perovskite structure with transformation from cubic to rhombohedral at thermal decomposition temperature higher than 900 °C in LSMO samples ofx ≤ 0.3. Basic magnetic characteristics such as saturated magnetization (M
S) and coercive field (H
C) were evaluated by vibrating sample magnetometry at room temperature (20 °C). The samples show paramagnetic behavior for all the samples withx = 0 or LMO, and a superparamagnetic behavior for the other samples havingM
Svalues of ~20–47 emu/g and theH
Cvalues of ~10–40 Oe, depending on the crystallite size and thermal decomposition temperature. Cytotoxicity of the synthesized LSMO nanoparticles was also evaluated with NIH 3T3 cells and the result shows that the synthesized nanoparticles were not toxic to the cells as determined from cell viability in response to the liquid extract of LSMO nanoparticles.
A gastrin‐releasing peptide receptor antagonist stimulates Neuro2a neuroblastoma cell growth: Prevention by a histone deacetylase inhibitor
Authors: Abujamra Ana Lucia , Almeida Viviane R. , Brunetto Algemir L. , Schwartsmann Gilberto , Roesler Rafael 
Published: May 2009

AbstractGastrin‐releasing peptide (GRP) acts as an autocrine growth factor for neuroblastoma and other types of cancer, and its cell‐surface receptor, GRPR, is overexpressed in advanced‐stage human neuroblastoma. GRPR knockdown and GRPR antagonism inhibit the growth of experimental neuroblastoma. Here we show that a GRPR antagonist promotes rather than inhibits the growth of neuroblastoma cells. The GRPR antagonist, RC‐3095, at 0.1 nM inhibited, whereas at 100 nM stimulated proliferation of Neuro2a murine neuroblastoma cells in vitro. The stimulatory effects were prevented by the histone deacetylase inhibitor (HDACi), sodium butyrate (NaB). Expression of GRPR mRNA in Neuro2a cells was analyzed by RT‐PCR. These findings provide evidence that a GRPR antagonist can stimulate the growth of cancer cells, and suggest that GRPR might interact with epigenetic mechanisms in regulating neuroblastoma cell growth.
Simulated microgravity induce glutathione antioxidant pathwayin Xenopus laevis embryos
Authors: Rizzo Angela M. , Montorfano Gigliola , Negroni Manuela , Corsetto Paola , Berselli Patrizia , Marciani Paola , Zava Stefania , Berra Bruno 
Published: May 2009

AbstractSpace flights cause a number of patho‐physiological changes. Oxidative damage has been demonstrated in astronauts after space flights. Oxidative stress is due to an imbalance between production of oxidant and antioxidative defence. In embryos of Xenopus laevis, the glutathione system is an inducible antioxidant defence. For this reason, we investigated the effect of gravity deprivation on endogenous antioxidant enzymes in X. laevis embryos developed for 6 days in a Random Positioning Machine. The results show that glutathione content and the activity of antioxidant enzymes increase in RPM embryos, suggesting the presence of a protective mechanism. An induction of antioxidant defence might play an important role for animals to adapt to micro‐gravitational stress, possibly during actual space flights.