bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viscoelasticity of Asphalts Modified with SEBS Copolymers Functionalized with Various Amounts of Maleic Anhydride
Authors: Vargas M. A. , López N. N. , Cruz M. J. , Calderas F. , Manero O. 
Published: February 2011

Abstract
It is known that the microstructure of polymer-modified asphalts (PMA) depends strongly of the characteristics of the polymer. The modifier polymer improves the mechanical properties of pure asphalt when used in paved roads. In this work, asphalt is modified using reactive polymers obtained via functionalization of styrene-ethylene/butylene-styrene (SEBS) copolymers in solution using various amounts of benzoil peroxide (BPO) as initiator and maleic anhydride (MAH). The resulting functionalized copolymer (SEBS-g-MAH) with variable amounts of grafting (variable reactivity) is blended with the asphalt at small contents (2–4 wt. %). The amount of MAH grafting was determined by FTIR, 1HNMR, GPC, DSC and by titration with KOH, and this amount is readily correlated with the improvement of the mechanical properties and thermal stability of the asphalt. In addition, the limit of the polymer-asphalt compatibility is determined for these systems.
Recent Advances in Structural Characterization of Natural Rubber
Authors: Tanaka Yasuyuki , Tarachiwin Lucksanaporn 
Published: February 2011

Abstract
Structural characterization of rubber from Hevea brasiliensis (NR) has been carried out to elucidate the biosynthesis mechanism of rubber molecule as well as to find the relationship between physical properties characteristic of NR and its structure. Recent advances of structural studies have provided a series of new information on the structure of long-chain branching based on the result of selective decomposition of branch-points by chemical and enzymatic treatments as well as physical treatment such as polar solvent treatments and washing of NR latex by centrifugation in the presence of a surfactant. The measurement of the resulting rubber with NMR, FTIR, SEC and dilute solution viscosity provided confirming evidence that the initiating terminal (ω-terminal) with an unidentified functional group and phosphate terminal (α-terminal) form branch-points by hydrogen bond, ionic bond or micelle formation of phospholipids linked to both terminal groups. Based on these results, the origin of green properties characteristic of NR has been explained and a new mechanism of storage hardening has been proposed. The purification method by saponification of NR latex developed for the structural characterization has been applied to produce purified NR latex free from Type I allergic reaction. Instantaneous coagulation of saponified latex by the use of a flocculant and formic acid has provided solid saponified NR having good green and cured rubber properties.
Mixing, Curing and Reinforcement of NR/BR/EPDM Blends for Tire Sidewall Applications
Authors: Zhang H. , Datta R. N. , Talma A. G. , Noordermeer J. W. M. 
Published: February 2011

Abstract
Tire sidewalls generally consist of blends of natural rubber (NR) and butadiene rubber (BR), containing a high concentration of antiozonants to provide ozone resistance. However, the most widely used antiozonant, N-(1, 3-dimethyl-butyl)-N'-phenyl-p-phenylenediamine (6PPD), is a staining, toxic and environmentally unfriendly substance. Incorporation of Ethylene-Propylene-Diene rubber (EPDM) into NR/BR is a way of achieving non-staining ozone resistance. But blending of dissimilar rubbers is severely restricted due to viscosity mismatch, thermodynamic incompatibility, cure incompatibility and heterogeneous filler distribution. This chapter gives an overview of the various research approaches in the field of blending dissimilar rubbers so far, as well as the mechanism of ozone protection by incorporation of EPDM in tire sidewall applications.
Mechanistic Studies into the New Concept of Co-Agents for Scorch Delay and Property Improvement in Peroxide Vulcanization
Authors: Alvarez Grima M. M. , Eriksson J. G. , Talma A. G. , Datta R. N. , Noordermeer J. W. M. 
Published: February 2011

Abstract
In previous studies a new concept of a peroxide cure system for rubber has been reported where scorch safety and mechanical properties are improved at the same time. This new system consists of the use of a combination of a peroxide, a bismaleimide type co-agent and a sulfur spender for the cure of saturated or low-unsaturated rubber. Several mechanical properties have been studied and were found to be improved by using this curing system, such as tensile strength, moduli, compression set and aging. The present paper deals with the understanding of the reported phenomena. Mechanistic studies have been performed with the aim of comprehending the chemistry that takes place during peroxide vulcanization in the presence of a maleimide co-agent and a sulfur spender. From Nuclear Magnetic Resonance and Infrared analysis the loss of the maleimide unsaturation from the co-agent was observed, due to reaction with the sulfur spender. This reaction already takes place at room temperature, thus previous to peroxide decomposition. Further, Model Compound Vulcanization studies were performed using 3-methylpentane as representative model for the saturated rubber backbone. The reaction products of the peroxide vulcanization of 3-methylpentane in the presence of a maleimide type co-agent and a sulfur donor have been analyzed by means of Liquid Chromatography-Mass Spectrometry. Several reaction products have been identified and a reaction mechanism that explains the scorch delay and the property improvement by the new cure system is proposed.
Pelletizing
Authors: Todd Baker D. B. 
Published: February 2011

Abstract
In the production of thermoplastics, the primary products frequently leave the manufacturing facility in the form of pellets. Incorporation of antioxidants, stabilizers, colors, fillers, reinforcing agents, and other additives requires that the polymer be in the melt stage to assure uniform distribution. After incorporation the melt is pelletized into uniform sizes and shapes to facilitate handling.
Casting
Authors: Harbison William C. 
Published: February 2011

AbstractCasting is the process whereby a liquid is poured into a mold and allowed to react, cure, or harden to form a rigid object that reproduces the mold cavity. Many resin systems may be utilized in this process, eg, acrylic, diethylene glycol bis(allyl carbonate), epoxy, phenol–formaldehyde, polystyrene, polysulfide, and silicone. Methyl methacrylate is the principle monomer used in the casting, or bulk polymerization, of acrylic plastics.
Specific Near‐IR Absorption Imaging of Glioblastomas Using Integrin‐Targeting Gold Nanorods
Authors: Choi Jihye , Yang Jaemoon , Park Joseph , Kim Eunjung , Suh Jin‐Suck , Huh Yong‐Min , Haam Seungjoo 
Published: February 2011

AbstractMolecular imaging using nanoprobes with high resolution and low toxicity is essential in early cancer detection. Here we introduce a new class of smart imaging probes employing PEGylated gold nanorods (GNRs) conjugated to cRGD for specific optical imaging of αvβ3 integrins from glioblastoma. GNRs exhibiting an optical resonance peak in the near‐infrared (NIR) region were synthesized using the seed‐mediated growth method. CTAB (cetyl trimethylammonium bromide) bilayer on the GNRs was replaced with a biocompatible stabilizer, heterobifunctional polyethyleneglycol (COOH‐PEG‐SH). Further, the carboxylated GNRs (PGNRs; PEG‐coated GNRs) were functionalized with cRGD using EDC‐NHS chemistry to formulate cRGD‐conjugated GNRs (cRGD‐PGNRs) for αvβ3 integrins. In order to assess the potential of the cRGD‐PGNRs as a targeted imaging probe, we investigated their optical properties, biocompatibility, colloidal stability and in vitro/in vivo binding affinities for cancer cells. Consequently, cRGD‐PGNRs demonstrated excellent tumor targeting ability with no cytotoxicity, as well as sufficient cellular uptake due to stable and prolonged blood circulation of cRGD‐PGNRs.
Self‐Tuning the Carrier Concentration of PbTe/Ag2Te Composites with Excess Ag for High Thermoelectric Performance
Authors: Pei Yanzhong , May Andrew F. , Snyder G. Jeffrey 
Published: February 2011

AbstractThermoelectric materials can be optimized by tuning the carrier concentration with chemical doping. However, because the optimum dopant concentration typically increases with temperature, the optimum efficiency can not normally be achieved for a uniform material in a temperature gradient. Here, we show Ag‐doped PbTe/Ag2Te composites exhibit high thermoelectric performance (∼50% greater than La‐doped composites) because of a temperature induced gradient in the doping concentration caused by the temperature‐dependent solubility of Ag in the PbTe matrix. This demonstrates a new mechanism to achieve a higher thermoelectric efficiency afforded by a given material system, and should be applicable to other thermoelectric materials.
Another case of multiple juxtasutural hyperostoses, cervical exostoses, and fatty infiltration of myocardium
Authors: Kannu Peter , Perry David , Rees Martin , O'Donnell Clare , Aftimos Salim 
Published: February 2011

AbstractWe report on an individual affected by multiple juxtasutural cranial hyperostoses who later developed cervical spine hyperostoses with associated fusion anomalies. The propositus was not affected by a disorder of generalized overgrowth. An echocardiogram revealed areas of abnormal signal within the myocardium which were consistent with fatty infiltration on magnetic resonance imaging of the heart. We compare our case with a few previously reported cases that share phenotypic similarities but differ in some other clinical aspects. It is possible that these patients represent a phenotypic continuum resulting from a somatic mutation in an unknown gene. © 2011 Wiley‐Liss, Inc.
Hajdu–Cheney syndrome with severe dural ectasia
Authors: Avela Kristiina , Valanne Leena , Helenius Ilkka , Mäkitie Outi 
Published: February 2011

AbstractHajdu–Cheney syndrome (HCS) is an autosomal dominant condition comprising osteolysis of the terminal phalanges, characteristic craniofacial abnormalities, dental anomalies, and proportionate short stature. The clinical and radiological findings develop and progress with age. Here, we report on a HCS patient with severe scoliosis and exceptionally massive dural ectasia. Congenital scoliosis and dural ectasia have not been reported previously in HCS. © 2011 Wiley‐Liss, Inc.
Variable expression of neurofibromatosis 1 in monozygotic twins
Authors: Rieley Margaret B. , Stevenson David A. , Viskochil David H. , Tinkle Brad T. , Martin Lisa J. , Schorry Elizabeth K. 
Published: February 2011

AbstractNeurofibromatosis 1 (NF1) is a common autosomal dominant disorder with high penetrance but extreme variability of expression. Monozygotic (MZ) twins with NF1 who have phenotypic discordances are a useful tool in evaluating which traits are influenced by non‐hereditary influences such as second hit somatic events, environmental agents, epigenetic modification, or post‐zygotic mutations. We evaluated nine sets of MZ twins and one set of MZ triplets, ages 4–18 years, for NF1 features and calculated probandwise concordance (PC) for each feature. MZ twins were highly concordant in numbers of café‐au‐lait spots (PC = 0.89) and cutaneous neurofibromas. IQ scores were within 10 points for all twin pairs tested, and similar patterns of learning disabilities and speech disorders were observed. Twin pairs showed significant discordance for tumors, particularly plexiform neurofibromas (PC = 0.40) and malignant peripheral nerves sheath tumors (MPNST), as expected if post‐natal second‐hit events were contributing to these features. One set of twins was concordant for multiple, large paraspinal neurofibromas, suggesting that there may be more hereditary factors involved in production of paraspinal neurofibromas. Four sets were concordant for pectus deformities of the chest (PC = 0.80). Three sets of twins were discordant for scoliosis (PC = 0.40); an additional set was concordant for scoliosis but differed in presence of dystrophic features and need for surgery. Our data suggest there are additional non‐hereditary factors modifying the NF1 phenotype and causing discordancies between MZ twins. Future studies may focus on differences in epigenetic changes or somatic mosaicism which have been documented for other disease genes in MZ twins. © 2011 Wiley‐Liss, Inc.
Genetic dosage compensation in a family with velo‐cardio‐facial/DiGeorge/22q11.2 deletion syndrome
Authors: Alkalay Avishai A. , Guo Tingwei , Montagna Cristina , Digilio M. Cristina , Dallapiccola Bruno , Marino Bruno , Morrow Bernice 
Published: February 2011

AbstractCytogenetic studies of a male child carrying the 22q11.2 deletion common in patients with velo‐cardio‐facial/DiGeorge syndrome showed an unexpected rearrangement of the 22q11.2 region in his normal appearing mother. The mother carried a 3 Mb deletion on one copy and a reciprocal, similar sized duplication on the other copy of chromosome 22q11.2 as shown by fluorescence in situ hybridization and array comparative genome hybridization analyses. The most parsimonious mechanism for the rearrangement is a mitotic non‐allelic homologous recombination event in a cell in the early embryo soon after fertilization. The normal phenotype of the mother can be explained by the theory of genetic dosage compensation. This is the second documented case of such an event for this or any genomic disorder. This finding helps to reinforce this phenomenon in a human model, and has significant implications for recurrence risks for the dose‐compensated mother. © 2011 Wiley‐Liss, Inc.
Descriptive study of nonsyndromic atrioventricular septal defects in the National Birth Defects Prevention Study, 1997–2005
Authors: Hartman Robert J. , Riehle‐Colarusso Tiffany , Lin Angela , Frías Jaime L. , Patel Sonali S. , Duwe Kara , Correa Adolfo , Rasmussen Sonja A. ,   The National Birth Defects Prevention Study
Published: February 2011

AbstractNonsyndromic atrioventricular septal defects (AVSDs) are serious congenital heart defects for which information on prevalence and descriptive characteristics based on large, geographically, and ethnically diverse populations has been limited. To describe the birth prevalence and phenotype of nonsyndromic AVSDs, we used data from the National Birth Defects Prevention Study (NBDPS), a multisite, population‐based case–control study aimed at identifying genetic and environmental risk factors for birth defects. For this analysis, infants born during the period 1997–2005 and meeting the NBDPS case definition for AVSDs were included. Infants with an AVSD associated with recognized or strongly suspected chromosomal abnormalities or single‐gene disorders (syndromic case infants) were excluded. We identified 302 infants with a nonsyndromic AVSD for a birth prevalence of 0.83/10,000 livebirths. Over 20% of infants with an AVSD had an additional major birth defect, with gastrointestinal, renal or urinary, and central nervous system defects being the most common. A lower prevalence of AVSDs was seen among infants born to Hispanic mothers compared with those born to non‐Hispanic White mothers [prevalence ratio = 0.63 (95% confidence interval: 0.46–0.86)]. Understanding the prevalence of nonsyndromic AVSDs, demographic factors associated with their occurrence, and associated defects could help guide clinical care, as well as contribute to a better understanding of pathogenesis. © 2011 Wiley‐Liss, Inc.
Carnitine and coenzyme Q10 levels in individuals with Prader–Willi syndrome
Authors: Miller Jennifer L. , Lynn Christy H. , Shuster Jonathan , Driscoll Daniel J. 
Published: February 2011

AbstractCarnitine deficiency or coenzyme Q10 (CoQ10) deficiency may present with hypotonia, poor growth, easy fatigability, and apnea. This constellation of findings can also be seen in individuals with Prader–Willi syndrome (PWS). Animal studies indicate that increased fat mass due to obesity negatively correlates with both carnitine and CoQ10 levels in skeletal muscle. Increased body fat and obesity are characteristic of individuals with PWS. Currently, there is no documentation of serum carnitine levels, and only one study investigating plasma CoQ10 levels, in individuals with PWS. Fasting serum carnitine and plasma CoQ10 levels were measured in 40 individuals with molecularly confirmed PWS (ages 1–27 years; 19 F/21 M), 11 individuals with early‐onset morbid obesity of unknown etiology (ages 3–13 years; 5 F/6 M), and 35 control siblings from both groups (ages 1–24 years; 19 F/16 M). There were no significant differences among the three groups in either total carnitine, free carnitine, or CoQ10 levels. However, individuals with PWS had higher serum levels of carnitine esters (P = 0.013) and higher ester‐to‐free carnitine ratios (P = 0.0096) than controls suggesting a possible underlying impairment of peripheral carnitine utilization and mitochondrial energy metabolism in some individuals with PWS. Serum sampling identified no significant differences in total and free carnitine or CoQ10 levels between individuals with PWS, obese individuals, and sibling control groups. Muscle biopsy or measurement in leukocytes or cultured skin fibroblasts could be a better method to identify abnormalities in carnitine and CoQ10 metabolism in individuals with PWS than peripheral blood sampling. © 2011 Wiley‐Liss, Inc.
Eye‐tracking with nonhuman primates is now more accessible than ever before
Authors: Machado Christopher J. , Nelson Eric E. 
Published: February 2011

AbstractHuman and nonhuman primates rely almost exclusively on vision for social communication. Therefore, tracking eye movements and examining visual scan paths can provide a wealth of information about many aspects of primate social information processing. Although eye‐tracking techniques have been utilized with humans for some time, similar studies in nonhuman primates have been less frequent over recent decades. This has largely been owing to the need for invasive manipulations, such as the surgical implantation of devices to limit head movement, which may not be possible in some laboratories or at some universities, or may not be congruent with some experimental aims (i.e., longitudinal studies). It is important for all nonhuman primate researchers interested in visual information processing or operant behavior to realize that such invasive procedures are no longer necessary. Here, we briefly describe new methods for fully noninvasive video eye‐tracking with adult rhesus monkeys (Macaca mulatta). We also describe training protocols that require only ∼30 days to accomplish and quality control measures that promote reliable data collection. It is our hope that this brief overview will reacquaint nonhuman primate researchers with the benefits of eye‐tracking and promote expanded use of this powerful methodology. Am. J. Primatol. 73: 562–569, 2011. © 2011 Wiley‐Liss, Inc.
Brain alkalosis causes birth asphyxia seizures, suggesting therapeutic strategy
Authors: Helmy Mohamed M. , Tolner Else A. , Vanhatalo Sampsa , Voipio Juha , Kaila Kai 
Published: February 2011

AbstractObjective:The mechanisms whereby birth asphyxia leads to generation of seizures remain unidentified. To study the possible role of brain pH changes, we used a rodent model that mimics the alterations in systemic CO2 and O2 levels during and after intrapartum birth asphyxia.Methods:Neonatal rat pups were exposed for 1 hour to hypercapnia (20% CO2 in the inhaled gas), hypoxia (9% O2), or both (asphyxic conditions). CO2 levels of 10% and 5% were used for graded restoration of normocapnia. Seizures were characterized behaviorally and utilizing intracranial electroencephalography. Brain pH and oxygen were measured with intracortical microelectrodes, and blood pH, ionized calcium, carbon dioxide, oxygen, and lactate with a clinical device. The impact of the postexposure changes in brain pH on seizure burden was assessed during 2 hours after restoration of normoxia and normocapnia. N‐methyl‐isobutyl‐amiloride, an inhibitor of Na+/H+ exchange, was given intraperitoneally.Results:Whereas hypercapnia or hypoxia alone did not result in an appreciable postexposure seizure burden, recovery from asphyxic conditions was followed by a large seizure burden that was tightly paralleled by a rise in brain pH, but no change in brain oxygenation. By graded restoration of normocapnia after asphyxia, the alkaline shift in brain pH and the seizure burden were strongly suppressed. The seizures were virtually blocked by preapplication of N‐methyl‐isobutyl‐amiloride.Interpretation:Our data indicate that brain alkalosis after recovery from birth asphyxia plays a key role in the triggering of seizures. We question the current practice of rapid restoration of normocapnia in the immediate postasphyxic period, and suggest a novel therapeutic strategy based on graded restoration of normocapnia. Ann Neurol 2011
Transition to adult care for children with chronic neurological disorders
Authors: Camfield Peter , Camfield Carol 
Published: February 2011

AbstractChronic neurological disorders in children have significant effects on adult medical and social function. Transition and then formal transfer of care from pediatric to adult services is a complex process, although there are virtually no objective data to inform physicians about the most effective approach. Some neurological disorders that start in children are a danger to society if poorly treated in adulthood, some disorders that were previously lethal in childhood now permit survival well into adulthood, and others are static in childhood but progressive in adulthood. Some disorders remit or are cured in childhood but continue to have serious comorbidity in adulthood, whereas others are similar and persistent in children and adults. Maturity, provision of information, and cognitive problems are confounders. We discuss several models of transition/transfer but prefer a joint pediatric/adult transition clinic. We make a series of suggestions about how to improve the transition/transfer process with the hope of better medical and social adult outcome for children with neurological disorders. ANN NEUROL 2011