bluuebunny/crossref_metadata_2025_split huggingface dataset:
A hyperbranched, rotaxane‐type mechanically interlocked polymer
Authors: Li Shijun , Zheng Bo , Chen Jianzhuang , Dong Shengyi , Ma Zhi , Huang Feihe , Gibson Harry W. 
Published: August 2010

AbstractBased on the dibenzo‐24‐crown‐8/1,2‐bis(pyridinium)ethane recognition motif, a hyperbranched mechanically interlocked polymer was prepared by polyesterification of an easily available dynamic trifunctional AB2 pseudorotaxane monomer. It was characterized by various techniques including 1H NMR, COSY, NOESY, GPC, viscosity, TGA, dynamic laser light scattering, AFM, and SEM. Its GPC Mn was determined to be 191 kDa with polydispersity 1.7 and its hydrodynamic diameter in a dilute solution in acetone was about 70 nm. This measured Mn value corresponds to about 93 repeating units. The study reported here presents not only a new polymer topology but also a novel and convenient way to prepare mechanically interlocked polymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4067–4073, 2010
Mesoglobules of random copolyethers as templates for nanoparticles
Authors: Trzebicka Barbara , Weda Paweł , Utrata‐Wesołek Alicja , Dworak Andrzej , Tsvetanov Christo 
Published: August 2010

AbstractAn approach to nanoparticles based upon the thermosensitivity of a copolyether is described. Two thermosensitive copolymers of glycidol with molar masses of 800,000 g/mol randomly substituted with ethyl isocyanate (28 and 35% substitution) were used to obtain mesoglobules. The effects of copolymer concentration and of the presence of surfactants (sodium dodecyl sulfate and hexadecyltrimethylammonium bromide) on the size of the mesoglobules formed were investigated. The obtained mesoglobules were monomodal and of narrowly distributed diameters, as shown by dynamic light scattering and atomic force microscopy measurements. The radical nucleated copolymerization of N‐isopropylacrylamide with N,N′‐methylenebisacrylamide as a crosslinker was performed in the presence of the mesoglobules. Nanoparticles of monomodal size distribution and low dispersity were obtained. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4074–4083, 2010
The synthesis of water‐soluble PHEMA via ARGET ATRP in protic media
Authors: Paterson Stefan M. , Brown David H. , Chirila Traian V. , Keen Imelda , Whittaker Andrew K. , Baker Murray V. 
Published: August 2010

Abstract2‐Hydroxyethyl methacrylate has been polymerized in methanol using activators regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP), to produce water‐soluble poly(2‐hydroxyethyl methacrylate) (PHEMA). The various parameters that determine control of the living polymerization have been explored. Using the Cu(II)/TPMA catalyst system (TPMA = tris(2‐pyridylmethyl)amine), controlled polymerization was achieved with Cu concentrations as low as 50 ppm relative to HEMA, with a [TPMA]/[Cu(II)] ratio of 5. Use of hydrazine as the reducing agent generally gave better control of polymerization than use of ascorbic acid. The polymerization conditions were tolerant of small amounts of air, and colorless polymers were easily isolated by simple precipitation and washing steps. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4084–4092, 2010
Amphiphilic silicones prepared from branched PEO‐silanes with siloxane tethers
Authors: Murthy Ranjini , Bailey Brennan M. , Valentin‐Rodriguez Celimar , Ivanisevic Albena , Grunlan Melissa A. 
Published: August 2010

AbstractAmphiphilic silicones were prepared by the covalent incorporation of branched polyethylene oxide (PEO) via a siloxane tether. This was achieved by using six novel branched PEO‐silanes with varying siloxane tether lengths and PEO molecular weight (Mn). Each PEO‐silane was crosslinked via acid‐catalyzed sol–gel condensation with α,ω‐bis(Si‐OH)polydimethylsiloxane (PDMS) (Mn = 3000 g/mol) to yield six amphiphilic silicone films. Film surface hydrophilicity increased with siloxane tether length, particularly after exposure to an aqueous environment, indicating that the PEO segments were more readily driven to the surface. This effect was more pronounced for films prepared with PEO‐silanes containing lower Mn PEO segments. AFM was used to study surface reconstruction of films upon exposure to an aqueous environment. Adsorption of bovine serum albumin (BSA) and human fibrinogen (HF) proteins decreased with siloxane tether length, particularly after first exposing films to an aqueous environment. For a given siloxane tether length, relatively less BSA adsorbed onto films prepared with PEO‐silanes with lower Mn PEO segments whereas less HF adsorbed onto films prepared with PEO‐silanes with higher Mn PEO segments. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4108–4119, 2010
Hierarchical structure in polymer‐based drug delivery systems as probed by calorimetric measurements
Authors: Valot Pascale , Sintes‐Zydowicz Nathalie , Nedelec Jean‐Marie , Baba Mohamed 
Published: August 2010

AbstractThermoporosimetry (TPM), a differential scanning calorimetry technique that relies on the shift of transition temperatures caused by the confinement of liquids, was applied to elucidate the complex morphology of drug‐loaded polymeric microcapsules prepared by the emulsion solvent evaporation method. For the very first time, TPM has been applied simultaneously with two liquids as structural probes. It was found that Miglyol, which dissolves the selected drug (Ibuprofen), is confined inside vesicles having a mean radius of 26.3 nm, whereas water, which is the continuous phase, is trapped inside a swollen polymeric network of Eudragit with an average mesh radius of 1.7 nm. A proposed hierarchical structure is given, which predicts that Eudragit microcapsules are formed from a collection of inert oil vesicles partitioned by polymeric Eudragit membranes swollen by water. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1939–1945, 2010
Crystallization kinetics of polymer brushes with poly(ethylene oxide) side chains
Authors: Zheng Ying , Bruening Merlin L. , Baker Gregory L. 
Published: August 2010

AbstractIsothermal crystallization rates of semicrystalline poly(methoxypoly(ethylene glycol) methacrylate) brushes on gold‐coated substrates were measured by polarized optical microscopy. Growth rates for crystal radii, which were essentially constant for each film, initially increased with film thickness and then leveled off for film thicknesses >300 nm. Avrami–Evans theory suggests that the spherulites exhibit one‐dimensional growth with heterogeneous nucleation. Compared with physisorbed analogs, polymer brushes crystallized slower due to the restriction of chain mobility. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1955–1959, 2010
Near‐infrared spectroscopy for the quantitative determination of mass transfer and water absorption kinetics by a polymer solution
Authors: Pochat‐Bohatier Céline , Werapun Warit , Bouyer Denis , Chinpa Watchanida , Deratani André 
Published: August 2010

AbstractThis article reports a new method to quantify the water absorption kinetics and the mass transfer in a polymer solution by using near‐infrared (NIR) spectroscopy and partial least‐squares (PLS) models, while it is exposed to a humid atmosphere. Polymer solutions used in this study were made with highly polar solvents exhibiting both a high affinity for water and a low volatility such as dimethylformamide, dimethylacetamide, and N‐methylpyrrolidone. Poly(ethersulfone) and poly(etherimide) were chosen as polymer models as the method could provide useful information for coating process and membrane fabrication monitoring. Whereas gravimetric kinetics yield data on the overall mass transfer, including both water absorption and solvent evaporation, in situ analyses using NIR can quantify separately the solvent and nonsolvent concentration change in the polymer solution. Quantitative models were developed using PLS regression to predict the local water, polymer, and solvent weight fractions in the polymer solution. The method was proved to be suitable for the different studied systems and allowed to infer mass transfers until the onset of the phase separation process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1960–1969, 2010
Protein resistance of polyurethane with hydrophilic and hydrophobic soft segments
Authors: Ma Chunfeng , Zhou Guoying , Zhang Guangzhao 
Published: August 2010

AbstractPolyurethane (PU) containing poly(propylene glycol) (PPG) or poly(tetramethylene oxide) (PTMG) soft segments have been prepared by two‐step condensation polymerization. The former (PPG‐PU) with a lower critical solution temperature (LCST) at ∼21 °C can change from hydrophilic to hydrophobic, whereas the latter (PTMG‐PU) is hydrophobic at a temperature above 0 °C. The adsorption of fibrinogen, bovine serum albumin, or lysozyme on such a PU surface in aqueous solution has been investigated by use of quartz crystal microbalance with dissipation (QCM‐D) and surface plasmon resonance (SPR) in real time. PPG‐PU surface exhibits protein resistance at a temperature below the LCST of PPG, but it significantly adsorbs proteins at a temperature above the LCST. On the other hand, the hydrophobic PTMG‐PU surface adsorb the proteins at any temperatures investigated, in contrast with the hydrated poly(ethylene glycol) exhibiting excellent protein resistance. The hydration and dehydration of the polymers at different temperatures were confirmed by Raman spectroscopy. Our study demonstrates that the protein resistance of polymers is determined by their hydration. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1987–1993, 2010
New simple method of measuring the surface glass transition temperature of polymers
Authors: Boiko Yuri M. 
Published: August 2010

AbstractA lap‐shear joint mechanical testing method has been probed to measure the surface glass transition temperature (T) of the thick bulk films of high‐molecular‐weight polymers. As T, the temperature transition “occurrence of autoadhesion–nonoccurrence of autoadhesion” has been proposed. The influence of chain flexibility, of molecular architecture, of polymer morphology, and of chain ends concentration on the T has been investigated. The correlation between the reduction in T with respect to the glass transition temperature of the bulk (T) and the intensity of the intermolecular interaction in the polymer bulk in amorphous polymers has been found. The effect of surface roughness on T has been discussed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2012–2021, 2010
Neutralization phenomena observed with secondary ions originating from inner‐shell excitation
Authors: Wittmaack Klaus 
Published: August 2010

AbstractThe observation of comparatively high yields of low‐energy secondary ions, ejected from clean ion‐bombarded solids, has been a long‐standing miracle. The measured velocity dependence of the ionization probability is at variance with the predicted exponential velocity dependence. It has been proposed that the recorded high yields are due to electronic excitations initiated by the collision cascade. Here, the issue is addressed by exploring energy spectra of ions generated by inner shell electron promotion during energetic collisions. Using new experimental results and literature data, ionization probabilities were determined using two different approaches. The evaluated data suggest that doubly charged ions of Mg, Al and Si (and possibly, Ca) can escape neutralization, presumably as a consequence of Auger deexcitation taking place at sufficiently large distances from the surface. The ion fractions for Sc, Ti, V and Cr are in accordance with an exponential velocity dependence at energies > 300 eV, but approach a constant level at low energies. Given the fact that the electronic‐excitation model does not apply in the case of ionization by electron promotion, it is suggested that the unusually high ionization probabilities observed at low energies are due to suppressed neutralization. The idea is that in a small fraction of impact events the collision cascade may generate a very high perturbation of the surface (‘dynamic randomization’) so that a well‐defined band structure may not exist, locally and for a short period of time. In these rare cases, the conduction electrons required for neutralization are not available. Copyright © 2010 John Wiley & Sons, Ltd.
Loss of Bright/ARID3a Function Promotes Developmental Plasticity
Authors: An Guangyu , Miner Cathrine A. , Nixon Jamee C. , Kincade Paul W. , Bryant James , Tucker Philip W. , Webb Carol F. 
Published: August 2010

AbstractB-cell regulator of immunoglobulin heavy chain transcription (Bright)/ARID3a, an A+T-rich interaction domain protein, was originally discovered in B lymphocyte lineage cells. However, expression patterns and high lethality levels in knockout mice suggested that it had additional functions. Three independent lines of evidence show that functional inhibition of Bright results in increased developmental plasticity. Bright-deficient cells from two mouse models expressed a number of pluripotency-associated gene products, expanded indefinitely, and spontaneously differentiated into cells of multiple lineages. Furthermore, direct knockdown of human Bright resulted in colonies capable of expressing multiple lineage markers. These data suggest that repression of this single molecule confers adult somatic cells with new developmental options.
Simultaneous LC‐MS/MS determination of phenylbutyrate, phenylacetate benzoate and their corresponding metabolites phenylacetylglutamine and hippurate in blood and urine
Authors: Laryea Maurice D. , Herebian Diran , Meissner Thomas , Mayatepek Ertan 
Published: August 2010

AbstractInborn errors of urea metabolism result in hyperammonemia. Treatment of urea cycle disorders can effectively lower plasma ammonium levels and results in survival in the majority of patients. Available medications for treating urea cycle disorders include sodium benzoate (BA), sodium phenylacetate (PAA), and sodium phenylbutyrate (PBA) and are given to provide alternate routes for disposition of waste nitrogen excretion. In this study, we develop and validate a liquid chromatography tandem mass spectrometry (LC‐MS/MS) method for simultaneous determination of benzoic acid, phenylacetic acid, phenylbutyric acid, phenylacetylglutamine, and hippuric acid in plasma and urine from children with inborn errors of urea synthesis. Plasma extracts and diluted urine samples were injected on a reverse‐phase column and identified and quantified by selected reaction monitoring (SRM) in negative ion mode. Deuterated analogues served as internal standards. Analysis time was 7 min. Assay precision, accuracy, and linearity and sample stability were determined using enriched samples. Quantification limits of the method were 100 ng/ml (0.3–0.8 μmol/L) for all analytes, and recoveries were >90%. Inter‐ and intraday relative standard deviations were <10%. Our newly developed LC‐MS/MS represents a robust, sensitive, and rapid method that allows simultaneous determination of the five compounds in plasma and urine.
Changes in gene expression after phencyclidine administration in developing rats: a potential animal model for schizophrenia
Authors: Liu F. , Zou X. , Sadovova N. , Zhang X. , Shi L. , Guo L. , Qian F. , Wen Z. , Patterson T.A. , Hanig J.P. , Paule M.G. , Slikker W. , Wang C. 
Published: August 2010

AbstractRepeated administration of phencyclidine (PCP), anN‐methyl‐d‐aspartate (NMDA) receptor antagonist, during development, may result in neuronal damage that leads to behavioral deficits in adulthood. The present study examined the potential neurotoxic effects of PCP exposure (10 mg/kg) in rats on postnatal days (PNDs) 7, 9 and 11 and the possible underlying mechanism(s) for neurotoxicity. Brain tissue was harvested for RNA extraction and morphological assessments. RNA was collected from the frontal cortex for DNA microarray analysis and quantitative RT‐PCR. Gene expression profiling was determined using Illumina Rat Ref‐12 Expression BeadChips containing 22,226 probes. Based on criteria of a fold‐change greater than 1.4 and aP‐value less than 0.05, 19 genes including NMDAR1 (N‐methyl‐d‐aspartate receptor) and four pro‐apoptotic genes were up‐regulated, and 25 genes including four anti‐apoptotic genes were down‐regulated, in the PCP‐treated group. In addition, the schizophrenia‐relevant genes, Bdnf (Brain‐derived neurotrophic factor) and Bhlhb2 (basic helix‐loop‐helix domain containing, class B, 2), were significantly different between the PCP and the control groups. Quantitative RT‐PCR confirmed the microarray results. Elevated neuronal cell death was further confirmed using Fluoro‐Jade C staining. These findings support the hypothesis that neurodegeneration caused by PCP occurs, at least in part, through the up‐regulation of NMDA receptors, which makes neurons possessing these receptors more vulnerable to endogenous glutamate. The changes in schizophrenia‐relevant genes after repeated PCP exposure during development may provide important information concerning the validation of an animal model for this disorder.
Automation of Human IgG, Glucose, Lactate, and Oxygen Assays on Biomek NXP Span-8 Automation Workstation and PARADIGM Detection Platform
Authors: Liu Li , Zhang Ruth , Pajak Laura 
Published: August 2010

When optimizing cell culture media for therapeutic antibody production cell lines, it is very important to monitor parameters such as IgG concentration, glucose and lactate levels, and oxygen consumption in culture medium in an automated high-throughput manner to ensure the desirable growth conditions. In this report, assays for measuring human IgG, glucose, and lactate concentrations, and oxygen consumption were automated using the Biomek NXP Span-8 workstation, and analyzed on the PARADIGM Detection Platform. The human-IgG homogeneous time-resolved fluorescence (HTRF) (All trademarks are the property of their respective owners.) assay from Cisbio Inc. (Cisbio US, Bedford, MA) was automated in a 384-well plate format and detected on the PARADIGM with a HTRF Detection Cartridge. Glucose and lactate assays were automated in a 96-well plate format and detected on the PARADIGM with a Fluorescence Intensity Cartridge. Oxygen consumption was determined by the 96-well calibration-free OxoPlate (All trademarks are the property of their respective owners.) (PreSens Inc., PreSens - Precision Sensing GmbH, Regensburg, Germany) and detected by the PARADIGM with a MultiMode Detection Cartridge. The data for human IgG, glucose, lactate, and oxygen consumption assays automated on the Biomek NXP demonstrate the accuracy and precision obtained using the automated protocols on the PARADIGM Detection Platform, with the user-friendly and assay-specific cartridges for easy, quick, and accurate detection. Using this as a model, one would be able to adapt these approaches to high-throughput media optimization and cell monitoring.
Web‐based application to project the burden of Alzheimer's disease
Authors: Colantuoni Elizabeth , Surplus Greg , Hackman Andre , Arrighi H. Michael , Brookmeyer Ron 
Published: August 2010

BackgroundHealth care planning and research would benefit from tools that enable researchers to project the future burden of Alzheimer's disease (AD) and evaluate the effect of potential interventions.MethodsWe created a web‐based application of the AD prevalence model developed by Brookmeyer et al (Am J Public Health 1998;88:1337–42; Alzheimers Dement 2007;3:186–91). The user defines the disease parameters and any interventions that may either reduce risk or slow disease progression. We expanded the parameters to include the cost and weights for disability‐adjusted life years.ApplicationThe secure, web‐based application generates detailed AD projections for each calendar year to 2050, and allows users to create personal accounts for them to save, retrieve, and modify the input parameters. The flexibility of the application is illustrated with a forecast for the state of Maryland, USA.ConclusionsThe application generates AD burden projections, costs, and disability‐adjusted life years, along with changes associated with potential interventions.
The inhibitory effect of genistein on hepatic steatosis is linked to visceral adipocyte metabolism in mice with diet-induced non-alcoholic fatty liver disease
Authors: Kim Mi-Hyun , Kang Kyung-Sun , Lee Yeon-Sook 
Published: August 2010

Non-alcoholic fatty liver disease (NAFLD) has been deeply associated with visceral adiposity, adipose tissue inflammation and a variety of adipocytokines. We reported previously that genistein inhibited NAFLD by enhancing fatty acid catabolism. However, this molecular approach focused on hepatic metabolism. Thus, we have attempted to determine whether this anti-steatotic effect of genistein is linked to visceral adipocyte metabolism. C57BL/6J mice were fed on normal-fat (NF) diet, high-fat (HF) diet and HF diet supplemented with genistein (1, 2 and 4 g/kg diet) for 12 weeks. Mice fed on the HF diet gained body weight, exhibited increased visceral fat mass and elevated levels of serum and liver lipids, and developed NAFLD, unlike what was observed in mice fed on the NF diet. However, genistein supplementation (2 and 4 g/kg diet) normalised these alternations. In the linear regression analysis, visceral fat (R0·77) and TNFα (R0·62) were strongly correlated with NAFLD among other NAFLD-related parameters. Genistein supplementation suppressed the hypertrophy of adipocytes via the up-regulation of genes involved in fatty acid β-oxidation, including PPARα, 5′-AMP-activated protein kinase and very long-chain acyl CoA dehydrogenase, as well as through the down-regulation of genes associated with adipogenesis or lipogenesis, including liver X receptor-α, sterol-regulatory element-binding protein-1c, PPARγ, retinoid X receptor-α and acetyl CoA carboxylase 2. Moreover, genistein supplementation augmented an anti-steatohepatitic adiponectin TNF and reduced a steatohepatitic TNFα. Collectively, these findings show that genistein may prevent NAFLD via the regulation of visceral adipocyte metabolism and adipocytokines.
Effect of dietary fibre mixture on growth and intestinal iron absorption in rats recovering from iron-deficiency anaemia
Authors: Koester Weber Thabata , de Cássia Freitas Karine , Amancio Olga Maria Silvério , Morais Mauro Batista de 
Published: August 2010

There is concern regarding the possible negative effects of ingestion of dietary fibre on growth and intestinal Fe absorption in infants. The aim of the present study was to compare the effect of a fibre mixture on the growth and the intestinal absorption of Fe in rats with Fe-deficiency anaemia with that of a diet without fibres. Faecal weight and caecal pH were also evaluated. According to the Hb depletion–repletion model, twenty-two male weaned Wistar rats were fed the AIN93-G diet without Fe until Fe-deficiency anaemia was induced with Hb < 70 g/l. The anaemic rats were divided into two groups: (1) fibre mixture group – fed 100 g of fibre mixture/kg of diet (soya polysaccharide, inulin, resistant starch, Arabic gum, fructo-oligossaccharide and cellulose) (n 11); (2) control group – fed without fibres (n 11). All diets had 157 mg of ferric citrate (30 mg of elemental Fe) added to lead to recovery from anaemia. Fe intestinal absorption was measured by Hb repletion efficiency (HRE) and apparent Fe intestinal absorption. The HRE was 44·8 (sd 9·5) % in the fibre mixture group and 43·0 (sd 9·5) % in the control group (P = 0·664). The apparent Fe absorption was 46·2 (sd 16·5) and 47·2 (sd 10·2) % (P = 0·861) in the fibre mixture and control groups, respectively. The faecal weight median was 6·17 g in the fibre mixture group and 2·11 g in the control group (P < 0·001). The caecal pH was in the same order: 6·11 (sd 0·59) and 7·07 (sd 0·34) (P < 0·001). Both the groups consumed similar quantities of diet, and growth was similar in both the groups. The fibre mixture had no influence either on growth or on Fe intestinal absorption in rats recovering from anaemia. This mixture favoured an increase in faecal weight and a decrease in caecal pH.