bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three‐dimensional Stokes flow caused by a translating–rotating sphere bisected by a free surface bounding a semi‐infinite micropolar fluid
Authors: Faltas M. S. , Saad E. I. 
Published: January 2008

AbstractExplicit velocity and microrotation components and systematic calculation of hydrodynamic quasistatic drag and couple in terms of nondimensional coefficients are presented for the flow problem of an incompressible asymmetrical steady semi‐infinite micropolar fluid arising from the motion of a sphere bisected by a free surface bounding a semi‐infinite micropolar fluid. Two asymmetrical cases are considered for the motion of the sphere: parallel translation to the free surface and rotation about a diameter which is lying in the free surface. The speed of the translational motion and the angular speed for the rotational motion of the sphere are assumed to be small so that the nonlinear terms in the equations of motion can be neglected under the usual Stokesian approximation. A linear slip, Basset‐type, boundary condition has been used. The variation of the resistance coefficients is studied numerically and plotted versus the micropolarity parameter and slip parameter. The two limiting cases of no‐slip and perfect slip are then recovered. Copyright © 2008 John Wiley & Sons, Ltd.
A compact multipoint flux approximation method with improved robustness
Authors: Aavatsmark I. , Eigestad G.T. , Mallison B.T. , Nordbotten J.M. 
Published: January 2008

AbstractMultipoint flux approximation (MPFA) methods were introduced to solve control‐volume formulations on general grids. Although these methods are general in the sense that they may be applied to any grid, their convergence and monotonicity properties vary. We introduce a new MPFA method for quadrilateral grids termed the L‐method. This method seeks to minimize the number of entries in the flux stencils, while honoring uniform flow fields. The methodology is valid for general media. For homogeneous media and uniform grids in two dimensions, this method has four‐point flux stencils and seven‐point cell stencils, whereas the MPFA O‐methods have six‐point flux stencils and nine‐point cell stencils. The reduced stencil of the L‐method appears as a consequence of adapting the method to the closest neighboring cells, or equivalently, to the dominating principal direction of anisotropy. We have tested the convergence and monotonicity properties for this method and compared it with the O‐methods. For moderate grids, the convergence rates are the same, but for rough grids with large aspect ratios, the convergence of the O‐methods is lost, while the L‐method converges with a reduced convergence rate. Also, the L‐method has a larger monotonicity range than the O‐methods. For homogeneous media and uniform parallelogram grids, the matrix of coefficients is an M‐matrix whenever the method is monotone. For strongly nonmonotone cases, the oscillations observed for the O‐methods are almost removed for the L‐method. Instead, extrema on no‐flow boundaries are observed. These undesired solutions, which only occur for parameters not common in applications, should be avoided by requiring that the previously derived monotonicity conditions are satisfied. For local grid refinements, test runs indicate that the L‐method yields almost optimal solutions, and that the solution is considerably better than the solutions obtained by the O‐methods. The efficiency of the linear solver is in many cases better for the L‐method than for the O‐methods. This is due to lower condition number and a reduced number of entries in the matrix of coefficients. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2008
Tribological performance and thermal behavior of epoxy resin nanocomposites containing polyurethane and organoclay
Authors: Jia Qingming , Shan Shaoyun , Wang Yaming , Gu Lili , Li Jinbo 
Published: January 2008

AbstractA series of epoxy resin nanocomposites modified by polyurethane and organically modified montmorillonite was prepared by effectively dispersing the organically modified montmorillonite in interpenetrating polymer networks (IPNs) of epoxy and polyurethane via the sequential polymeric technique and in situ polymerization. The tribological performance of the resultant EP/PU nanocomposites was investigated by a pin‐on‐disc tester, and the results showed that adding polyurethane and organically modified clay to the EP matrix had a synergistic effect on improving tribological performance of EP/PU nanocomposites. The morphologies of the worn surface were studied by scanning electron microscopy (SEM) observations, and the results indicated that the mechanism of improving tribological performance of EP/PU nanocomposites was different from that of pure EP or pure EP/PU IPNs. The thermal behavior of these nanocomposites was also investigated by thermogravimeric analysis (TGA), and the results indicated that adding organically modified clay to the matrix remedied the deterioration of the thermal degradation temperature of the interpenetrating networks. Copyright © 2008 John Wiley & Sons, Ltd.
Fluorene‐based polyester nanocomposites via in situ interlayer polymerization
Authors: Chang Jin‐Hae 
Published: January 2008

AbstractFluorene‐based polyester nanocomposites were prepared by in situ polymerization of equivalent weights of 9,9′‐dihexylfluorene‐2,7‐dicarboxylic acid and 4,4′‐dihydroxy‐1,4‐diphenoxybutane (DPB‐OH) in the presence of octadecyl‐montmorillonite (C18‐MMT) as an organoclay. We investigated the intercalation of the organoclay among the polymer chains, with the aim of improving the thermal properties of the polyester. It was found that the addition of only a small amount of organoclay was enough to improve the polyester's thermal properties. The maximum enhancement of the thermal properties of the fluorene‐based polyester nanocomposites was observed with the dispersion of 5 wt% organoclay. Copyright © 2008 John Wiley & Sons, Ltd.
Thermoelectrical and optical properties of double wall carbon nanotubes:polyaniline containing boron n‐type organic semiconductors
Authors: Yakuphanoglu Fahrettin , Şenkal B. Filiz 
Published: January 2008

AbstractThe electrical conductivity, thermoelectrical, and optical properties of the polyaniline containing boron/double wall carbon nanotubes (CNTs) composites have been investigated. The electrical conductivities of the composites prepared with 1%, 5%, and 8% CNT concentrations at 300 K were found to be 5.31 × 10−6, 2.72 × 10−4, and 1.12 × 10−3 (S/cm), respectively. The thermoelectrical results indicate that all the samples exhibit n‐type electrical conductivity. The optical band gaps of the samples were found to be 3.71 eV for 0% DWNT, 3.32 eV for 1% DWNT, 3.15 eV for 5% DWNT, and 3.12 eV for 8% DWNT. The obtained results suggest that the electrical conductivity of PANI‐B polymer is improved by DWNT doping. Copyright © 2008 John Wiley & Sons, Ltd.
The mTOR target 4E‐BP1 contributes to differential protein expression during normoxia and hypoxia through changes in mRNA translation efficiency
Authors: Magagnin Michaël G. , van den Beucken Twan , Sergeant Kjell , Lambin Philippe , Koritzinsky Marianne , Devreese Bart , Wouters Bradly G. 
Published: January 2008

AbstractHypoxia causes a rapid and sustained inhibition in mRNA translation that is characterized by both a transient phosphorylation of eukaryotic initiation factor 2‐alpha (eIF2α) and by inhibition of the mRNA cap binding protein eIF4E via activation of two distinct inhibitory proteins, the mammalian target of rapamycin (mTOR) target 4E‐BP1 and the eIF4E transporter 4E‐T. Although the importance of eIF2α phosphorylation during hypoxia has been clearly demonstrated, there is little information on the potential relevance of eIF4E regulation. We generated HeLa cells stably expressing a short hairpin interfering RNA (shRNA) against 4E‐BP1 and found that despite efficient knockdown, no significant changes occurred in the overall inhibition of mRNA translation during hypoxia. However, using a proteomics approach we identified seven proteins that were exclusively expressed in the 4E‐BP1 knockdown cells during both normoxic and hypoxic conditions. Further investigation of the transcriptional and translational regulation of these genes by quantitative RT‐PCR indicated that the loss of 4E‐BP1 causes a significant increase in the rate of protein synthesis of S100 calcium‐binding protein A4 (S100A4) and transgelin 2. These 4E‐BP1 regulated proteins have previously been associated with tumor cell motility, invasion and metastasis and may thus contribute to an adverse tumor phenotype.
Sequential detergent fractionation of primary neurons for proteomics studies
Authors: Bernocco Simonetta , Fondelli Costanza , Matteoni Silvia , Magnoni Letizia , Gotta Stefano , Terstappen Georg C. , Raggiaschi Roberto 
Published: January 2008

AbstractProteomics studies employing primary neurons are difficult due to the neurons' characteristics. We have developed a detergent‐based fractionation method which reduces complexity of the protein extracts, is sufficiently fast to allow differential proteomics analysis after treatments of neurons for short time periods, can be applied to small numbers of cells directly in culture plates, and allows differential extraction of proteins in a compartment‐specific manner. The sequential use of detergent‐containing buffers on neurons in culture plates yields four extracts enriched in cytosolic, membrane‐bound or enclosed, nuclear, and cytoskeletal proteins. Fractionation of neurons was validated by comparison of the distribution of known subcellular marker proteins in the four extracts using Western blotting. Comparison of extracts by DIGE showed a clear difference in protein composition demonstrating significant variations with a fold change (FC) of at least 1.20 for 82% of the detected spots. Using proteins identified in these spots that could be assigned a subcellular localization based on descriptions in the Uniprot database, an extraction efficiency of 85% was calculated for cytosolic proteins in extract 1, 90% for membrane‐bound and membrane‐enclosed proteins in extract 2, 82% for nuclear proteins in extract 3 and 38% for cytoskeletal and RAFT proteins in extract 4.
Studies on the conducting nanocomposite prepared by in situ polymerization of aniline monomers in a neat (aqueous) synthetic mica clay
Authors: Wu Chia‐Sheng , Huang Ying‐Jie , Hsieh Tar‐Hwa , Huang Ping‐Tsung , Hsieh Bi‐Zen , Han Yu‐Kai , Ho Ko‐Shan 
Published: January 2008

AbstractThe in situ polymerization of the anilinium‐intercalated synthetic mica clay can easily result in an intercalated polyaniline (PANI)/clay nanocomposite. The FT‐IR spectra demonstrated a significant shift for ν(CN) at 1292 cm−1 of the templated polymerized and intercalated PANI molecules. A red shift of λmax for PANI was found from UV–vis spectra. The intercalated PANI also expanded the clay basal spacing seen from WAXD patterns. The degradation rate and temperature of the nanocomposites were found to alleviate and increase compared to neat PANI, respectively. The microscopic examinations including TEM, SEM, and AFM pictures of the nanocomposite demonstrated an entirely different and more compatible morphology. Conductivity of nanocomposite gradually increased with PANI and apparent increase was found when intercalated PANI content reached 40.6 wt %, the possible percolation threshold. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1800–1809, 2008
Multifunctional materials based on polyazomethines derived from 2,5‐dihydroxy‐1,4‐benzoquinone and siloxane diamines
Authors: Cazacu Maria , Vlad Angelica , Munteanu Grigore , Airinei Anton 
Published: January 2008

AbstractNew polyazomethines have been synthesized by the reaction between 2,5‐dihydroxy‐1,4‐benzoquinone and siloxane diamines differing by the siloxane sequence length. A dimer has also been prepared as a model compound. The products were characterized by spectral (FTIR and 1H‐NMR) and elemental analyses, GPC, viscosity measurements, solubility tests, and transmission electron microscopy (TEM). The different properties have been investigated by adequate techniques: thermal (DSC and TGA), spectral (UV–vis and fluorescence spectroscopy), redox (Differential Pulse Voltammetry). pH‐sensitivity and metal complexing ability were also evaluated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1862–1872, 2008
Familial dysautonomia: Frequent, prolonged and severe hypoxemia during wakefulness and sleep
Authors: Weese‐Mayer Debra E. , Kenny Anna S. , Bennett Heather L. , Ramirez Jan‐Marino , Leurgans Sue E. 
Published: January 2008

AbstractSudden unexplained deaths have been reported in 32% of Familial Dysautonomia (FD) subjects. To characterize cardiorespiratory dysregulation in children with FD that might contribute to potential sudden death, respiratory inductance plethysmography (chest/abdomen), ECG, hemoglobin saturation, and pulse waveform (VivoMetrics, Inc.) were recorded in the home during daytime wakefulness and overnight sleep in 25 children with IKBKAP mutation‐confirmed FD and 25 age‐, and gender‐matched controls. Breath‐to‐breath and beat‐to‐beat characterization of breathing, hemoglobin saturation, and heart rate was conducted. Children with FD had more frequent, prolonged, and severe episodes of hypoxemia than matched controls, awake and asleep. Though a small percent of the study time revealed bradycardia and apnea, the hypoxemia was the most prevalent pattern in FD and rarely occurred with related bradycardia. Though infrequent with desaturation or bradycardia, apnea was more prevalent in FD subjects than controls, and more apparent during sleep than wakefulness. Children with FD have cardiorespiratory dysregulation during wakefulness and sleep, likely representing alveolar hypoventilation. We hypothesize that the related repeated hypoxemia (and presumed related hypercarbia) may render individuals with FD more vulnerable to sudden death. Pediatr Pulmonol. 2008; 43:251–260. © 2008 Wiley‐Liss, Inc.
Formation of Fmoc–β‐alanine during Fmoc‐protections with Fmoc–OSu
Authors: Obkircher Markus , Stähelin Christian , Dick Fritz 
Published: January 2008

AbstractDuring the Fmoc‐protection of H–α‐Me–Val–OH, an unknown side product was found and isolated. The characterization using various analytical methods led unambiguously to the result that Fmoc–β‐Ala–OH was formed during the reaction. The reagent Fmoc–OSu was proven to be the source of Fmoc–β‐Ala–OH, following a mechanism that involved many deprotonation and elimination steps and a Lossen‐type rearrangement as key sequence. The impurity Fmoc–β‐Ala‐OH was found in a variety of reactions in which Fmoc–OSu was applied, either in the reaction mixture or as a contamination of the crude product. Purification of the Fmoc–amino acid derivatives from this impurity incurred high costs and significant reductions in yield. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
β‐Actin‐derived peptides isolated from acidic extract of rat spleen suppress tumor cell growth
Authors: Blishchenko Elena Y. , Sazonova Olga V. , Yatskin Oleg N. , Kalinina Olga A. , Tolmazova Anna G. , Philippova Marina M. , Karelin Andrei A. , Ivanov Vadim T. 
Published: January 2008

AbstractTwenty‐two fragments of β‐actin and β‐actin‐related protein were isolated from the acidic extracts of rat spleen tissue. β‐Actin fragments (75–90), (78–89), and (78–88), 0.01–1 µM, decreased live cell number of L929 murine tumor fibroblasts by 80–90%, with maximal cytotoxic effect of 30–40%. The fragments of (78–90) segment and the fragment of β‐actin‐related protein (69–77) were less active (inhibitory effect up to 55%, cytotoxic–up to 25%). Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Solution conformations of bradykinin antagonists modified with CαCα cyclized nonaromatic residues
Authors: Sikorska Emilia , Rodziewicz‐MotowidŁo Sylwia 
Published: January 2008

AbstractThe conformations of four BK antagonists, [D‐Arg0, Hyp3, Thi5, D‐Phe7, Acc8]BK (1), Aaa[D‐Arg0, Hyp3, Thi5, D‐Phe7, Acc8]BK (2), [D‐Arg0, Hyp3, Thi5, 8, Apc7]BK (3), and Aaa[D‐Arg0, Hyp3, Thi5, 8, Apc7]BK (4) were studied by using 2D NMR spectroscopy and MD simulations with time‐averaged (TAV) restraints. According to the results of the NMR measurements, the BK antagonists contain 7–30% of minor conformation resulting from cis/trans isomerization of the peptide bonds preceding either Pro or Hyp residues. The major conformation of each peptide possesses all peptide bonds in trans configuration. Peptides modified with the Apc residue at position 7 (peptides 3 and 4) possess a higher percentage of minor isomer.Peptide 1 exhibits the strongest vasodepressor potency among the analogs studied and as a single one forms the βII‐turn in the 2–5 fragment, which is believed to be crucial for antagonistic activity. This peptide is also the most compact. The radius of gyration (Rg) amounts to 6.9 Å and is by ca 1.5 Å lower than that of the remaining analogs. With peptide 4, the ST‐turn of type I within the Ser6‐Thi8 fragment was found. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Strength in Numbers: Probing and Understanding Intermolecular Bonding with Chemical Force Microscopy
Authors: Noy Aleksandr 
Published: January 2008

AbstractScanning probe microscopy (SPM) provided researchers with a simple, intuitive, and versatile tool for probing intermolecular interactions using SPM probes functionalized with distinct chemical species. Chemical force microscopy (CFM) was developed as a way to probe and map these interactions in a rational and systematic way. But does the rupture strength of a bond measured in these experiments provide the definitive and useful information about the interaction? The answer to this question is closely linked to understanding the fundamental physics of bond rupture under an external loading force. Even a simple model shows that bond rupture can proceed in a variety of different regimes. I discuss the approaches for extracting quantitative information about the interaction from these experiments and show that even though the measured rupture force is almost never unique for a given bond, force spectroscopy measurements can still determine the essential interaction parameters. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.
System dynamics and group facilitation: contributions from communication theory
Authors: Visser Max 
Published: January 2008

AbstractIn this paper a theoretical approach to group facilitation is introduced, based on the work of the so‐called Palo Alto school in communication and psychotherapy. This approach permits an analysis of group facilitation processes on the basis of several important principles that also inform system dynamics model building and simulation. On the basis of this analysis existing lists of appropriate facilitation skills and attitudes may be supplemented with three guidelines, leading to greater insight into the quality of the process of group model building and possible ways to evaluate that process. Ultimately, the growth and proliferation of system dynamics models and simulations depend on improvement of both process and content of modeling and simulation. Copyright © 2007 John Wiley & Sons, Ltd.
A NEXAFS and XPS study of the adsorption of self‐assembling peptides on TiO2: the influence of the side chains
Authors: Iucci Giovanna , Battocchio Chiara , Dettin Monica , Gambaretto Roberta , Polzonetti Giovanni 
Published: January 2008

AbstractPeptides consisting of an alternation of hydrophobic and hydrophilic (positively and negatively charged) amino acids can generate extended ordered structures by self‐assembling (SA) from aqueous solutions. In this paper we present XPS, near‐edge X‐ray absorption fine structure (NEXAFS) and Fourier transform infrared (FTIR) investigations on a series of SA peptides with the aim of determining the effect of side‐chain length on molecular arrangement and orientation.Peptides were immobilised on the surface of titanium, a well‐known biocompatible material, or deposited as thick films on inert gold surfaces. FTIR analysis yields information on the backbone conformation. XPS spectroscopy was used to investigate the peptide adsorption on the TiO2 surface. The orientation of the peptide chains was investigated by angular‐dependent NEXAFS. Copyright © 2008 John Wiley & Sons, Ltd.
Management of Insulinomas: Analysis from a Tertiary Care Referral Center in India
Authors: Paul Thomas V. , Jacob Jubbin J. , Vasan Senthil K. , Thomas Nihal , Rajarathnam Simon , Selvan Ben , Paul M. J. , Abraham Deepak , Nair Aravindan , Seshadri M. S. 
Published: January 2008

AbstractThe aim of this study was to describe the localization and management of patients with pancreatic insulinomas and determine the most effective localization and surgical techniques in the presence of significant financial constraints in the patient population. We retrospectively reviewed the case records of 18 patients with insulinomas treated at our institution over a period of 10 years. The medical records were reviewed for demographic data, clinical presentation, biochemistry, details of localization studies, intraoperative findings, postoperative outcome, and long‐term follow‐up. The sensitivities of the various localization procedures were calculated using the intraoperative findings as the gold standard. There were 10 men and 8 women in the study, with a median age of 43 years. All patients underwent a supervised 72‐hour fast and developed symptomatic hypoglycemia within 48 hours. An average of 1.9 localization procedures was performed per patient. Computed tomography (CT) had a sensitivity of 62% and specificity of 100%. Magnetic resonance imaging and digital subtraction angiography had specificities of 85% and 100%, respectively, with a specificity of 66% and 50%, respectively. Fourteen patients underwent surgery. Intraoperatively the excised tumor was palpable in nine patients, and all patients had postoperative euglycemia. In five patients the tumor was not palpable during the time of surgery; three of these patients underwent blind distal pancreactomy, with two patients having persistent hypoglycemia during the postoperative period. Two patients had a negative exploratory laparotomy. Patients with a surgical cure were followed up for a mean period of 24 months. On the background of financial constraints in connection with patient care, CT scanning is a cost‐effective option with good specificity. Intraoperative palpation of the tumor and enucleation is the most effective technique for surgical cure. Blind distal pancreactomy is not advocated for tumors that are not localized intraoperatively.
Regional Variation in Hospital Mortality and 30‐day Mortality for Injured Medicare Patients
Authors: Gorra Adam S. , Clark David E. , Mullins Richard J. , DeLorenzo Michael A. 
Published: January 2008

AbstractBackgroundWe sought to evaluate how survival of older patients with injuries differs by geographic region within the United States.MethodsWe analyzed Medicare fee‐for‐service records for patients aged 65 years and older with principal injury diagnoses (ICD‐9 800–959, excluding 905, 930–939, 958). Cases were classified by Maximum Abbreviated Injury Score (AISmax) and Charlson Comorbidity score (0, 1, 2, ≥3). Hospital mortality and 30‐day mortality were modeled as functions of age, sex, AISmax, comorbidity, and geographic region (northeast, midwest, south, west).ResultsHospital and 30‐day mortality were both higher with male sex and increased age, AISmax, or Charlson score. Adjusted hospital mortality was highest in the northeast and south, but 30‐day adjusted mortality was lowest in the same two regions.ConclusionsRegional differences in risk‐adjusted hospital survival for older patients with injuries are different from regional differences in 30‐day survival. Hospital mortality as an outcome for older injured patients should be interpreted cautiously.