bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of hexafluoroisopropylidene isophthalic polyesters and copolyesters and the relationship between their structure and gas transport properties
Authors: Loría‐Bastarrachea María I. , Aguilar‐Vega Manuel 
Published: November 2006

AbstractTwo aromatic polyesters and three copolyesters were synthesized by interfacial polycondensation using 4,4′‐(hexafluoroisopropylidene)diphenol (HFD) and two phthalic dichlorides, isophthaloyl dichloride (ISO) and 5‐tertbutyl‐isophthaloyl dichloride (TERT). The polymers obtained were soluble in common chlorinated solvents. The properties of these aromatic polyesters and copolyesters were characterized by FTIR, density, inherent viscosity, TGA, and DSC. Thermal properties such as glass transition temperature, onset of decomposition, and thermal stability of the homopolymer, poly(hexafluoroisopropilydene)5‐tertbutylisophthalate (HFD/TERT), were higher than those of homopolymer poly(hexafluoroisopropilydene)isophthalate (HFD/ISO). Thermal properties of the copolyesters HFD/TERT‐co‐HFD/ISO depend upon the amounts of the tertbutyl group HFD/TERT, present in the copolymer. Gas permeability coefficients of all polyarylates were measured at 35°C. The effect of different concentrations of the bulky tertbutyl group at the 5‐position in the isophthaloyl moiety on He, O2, N2, and CO2 permeability, diffusion, and solubility coefficients were determined. Gas permeability and diffusivity increase as the concentration of TERT moiety increases in the copolymers. The results indicate that polymers containing the largest amounts of the bulky lateral tertbutyl group show the highest gas permeability. The increment in gas permeability and diffusivity produces a decrease in selectivity, which is attributed to the effect of the large pendant tertbutyl groups in the aromatic polyesters and copolyesters, which decrease the chain packing efficiency and induce a larger fractional free volume. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2207–2216, 2007
Optical properties of colloidal crystalline arrays composed of hollow polystyrene spheres
Authors: Nakamura Hiroshi , Ishii Masahiko 
Published: November 2006

AbstractWe have evaluated the optical properties of close‐packed and non close‐packed colloidal crystalline arrays made of hollow polystyrene spheres. Close‐packed colloidal crystalline arrays were fabricated by simple evaporation of dispersions, whereas nonclose‐packed colloidal crystalline arrays were fabricated by exploiting electrostatic interactions between the spheres in aqueous dispersion. Optical properties of the arrays were estimated from angle‐resolved reflection spectra. The Bragg diffraction peak of the colloidal crystalline array made of hollow spheres was of shorter wavelength than in the case of solid spheres, not only for the close‐packed array but also for the nonclose‐packed array. These shifts were caused by a decrease in the effective refractive index neff with decreasing particle refractive index. We have found that this relationship could be explained by the simple equation neff = nparticleϕ+ nsolvent (1 − ϕ), where ϕ is the volume fraction of the particles, for both close‐packed and non close‐packed arrays. The current work suggests new possibilities for the creation of advanced colloidal crystals. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2364–2368, 2007
Crystallization and morphology of cholesterol end‐capped poly(ethylene glycol)
Authors: Qiu Yuan‐Jin , Xu Jun‐Ting , Xue Liang , Fan Zhi‐Qiang , Wu Zhong‐Hua 
Published: November 2006

AbstractCrystallization and morphology of polyethylene glycol with molecular weight Mn = 2000 (PEG2000) capped with cholesterol at one end (CS‐PEG2000) and at both ends (CS‐PEG2000‐CS) were investigated. It is found that the bulky cholesteryl end group can retard crystallization rate and decrease crystallinity of PEG, especially for CS‐PEG2000‐CS. Isothermal crystallization kinetics shows that the Avrami exponent of CS‐PEG2000 decreases as crystallization temperature (Tc). The Avrami exponent of CS‐PEG2000‐CS increases slightly with Tc, but it is lower than that of CS‐PEG2000. Compared to the perfect spherulite morphology of PEG2000, CS‐PEG2000 exhibits irregular and leaf‐like spherulite morphology, while only needle‐like crystals are observed in CS‐PEG2000‐CS. The linear growth rate of CS‐PEG2000 shows a stronger dependence on Tc than PEG2000. The cholesterol end group alters not only the free energy of the folding surface, but also the temperature range of crystallization regime. The small angle X‐ray scattering (SAXS) results show that lamellar structures are formed in all these three samples. By comparing the long periods obtained from SAXS with the theoretically calculated values, we find that the PEG chains are extended in PEG2000 and CS‐PEG2000, but they are once‐folded in CS‐PEG2000‐CS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2464–2471, 2007
Mechanical and tribological properties of glass–epoxy composites with and without graphite particulate filler
Authors: Suresha B. , Chandramohan G. , Renukappa N. M. , Siddaramaiah  
Published: November 2006

AbstractThe objectives of this research article is to evaluate the mechanical and tribological properties of glass‐fiber‐reinforced epoxy (G–E) composites with and without graphite particulate filler. The laminates were fabricated by a dry hand layup technique. The mechanical properties, including tensile strength, tensile modulus, elongation at break, and surface hardness, were investigated in accordance with ASTM standards. From the experimental investigation, we found that the tensile strength and dimensional stability of the G–E composite increased with increasing graphite content. The effect of filler content (0–7.5 wt %) and sliding distance on the friction and wear behavior of the graphite‐filled G–E composite systems were studied. Also, conventional weighing, determination of the coefficient of friction, and examination of the worn surface morphological features by scanning electron microscopy (SEM) were done. A marginal increase in the coefficient of friction with sliding distance for the unfilled composites was noticed, but a slight reduction was noticed for the graphite‐filled composites. The 7.5% graphite‐filled G–E composite showed a lower friction coefficient for the sliding distances used. The wear loss of the composites decreased with increasing weight fraction of graphite filler and increased with increasing sliding distance. Failure mechanisms of the worn surfaces of the filled composites were established with SEM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2472–2480, 2007
Injection‐molded short hemp fiber/glass fiber‐reinforced polypropylene hybrid composites—Mechanical, water absorption and thermal properties
Authors: Panthapulakkal Suhara , Sain Mohini 
Published: November 2006

AbstractNatural fiber‐based thermoplastic composites are generally lower in strength performance compared to thermoset composites. However, they have the advantage of design flexibility and recycling possibilities. Hybridization with small amounts of synthetic fibers makes these natural fiber composites more suitable for technical applications such as automotive interior parts. Hemp fiber is one of the important lignocellulosic bast fiber and has been used as reinforcement for industrial applications. This study focused on the performance of injection‐molded short hemp fiber and hemp/glass fiber hybrid polypropylene composites. Results showed that hybridization with glass fiber enhanced the performance properties. A value of 101 MPa for flexural strength and 5.5 GPa for the flexural modulus is achieved from a hybrid composite containing 25 wt % of hemp and 15 wt % of glass. Notched Izod impact strength of the hybrid composites exhibited great enhancement (34%). Analysis of fiber length distribution in the composite and fracture surface was performed to study the fiber breakage and fracture mechanism. Thermal properties and resistance to water absorption properties of the hemp fiber composites were improved by hybridization with glass fibers. Overall studies indicated that the short hemp/glass fiber hybrid polypropylene composites are promising candidates for structural applications where high stiffness and thermal resistance is required. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2432–2441, 2007
A Method of Orthogonal Oligosaccharide Synthesis Leading to a Combinatorial Library Based on Stationary Solid‐Phase Reaction
Authors: Ako Takuro , Daikoku Shusaku , Ohtsuka Isao , Kato Rumiko , Kanie Osamu 
Published: November 2006

AbstractA new, efficient synthesis of oligosaccharides, which involves solid‐phase reactions without mixing in combination with an orthogonal‐glycosylation strategy, is described. Despite a great deal of biological interest, the combinatorial chemistry of oligosaccharides is an extremely difficult subject. The problems include 1) lengthy synthetic protocols required for the synthesis and 2) the variety of glycosylation conditions necessary for individual reactions. These issues were addressed and solved by using the orthogonal‐coupling protocol and the application of a temperature gradient to provide appropriate conditions for individual reactions. Furthermore, we succeeded in carrying out solid‐phase reactions with neither mechanical mixing nor flow. In this report, the synthesis of a series of trisaccharides, namely, α/β‐L‐Fuc‐(1→6)‐α/β‐D‐Gal‐(1→2/3/4/6)‐α/β‐D‐Glc‐octyl, is reported to demonstrate the eligibility of the synthetic method in combinatorial chemistry.
Triphalangeal thumb in association with split hand/foot: A phenotypic marker for SHFM3?
Authors: Elliott Alison M. , Reed Martin H. , Evans Jane A. 
Published: November 2006

AbstractBACKGROUND: At least five distinct loci have been implicated in split hand foot malformation (SHFM). Establishing genotype/phenotype correlations at the chromosomal level may elucidate responsible developmental genes and improve patient management. In our analysis of previously published genetically mapped SHFM cases, preaxial hand involvement was a significant discriminating variable, most commonly seen at the SHFM3 locus (OMIM 600095) at 10q24. Of the 47 SHFM3 patients analyzed, 15 (31.9%) had triphalangeal thumb (TPT), a limb finding not reported at any other locus. METHODS: The association of TPT/split foot, in particular, prompted us to review the literature for similar cases. RESULTS: We ascertained a number of unmapped familial and sporadic cases with TPT/split foot, including a group of patients with triphalangeal thumb‐brachyectrodactyly syndrome. Certain trends were similar in both SHFM3 and these unmapped literature cases. With respect to gender, 7/12 (58%) of mapped SHFM3 cases with TPT/split foot were male whereas 5/12 (42%) were female, compared with 22/50 (44%) males and 28/50 (56%) females among unmapped cases (P = 0.3715). Individuals in both groups usually had bilateral involvement, with 67 and 60% showing bilateral TPT among mapped and literature cases, respectively (P = 0.6714). Bilateral involvement of the feet was even more striking (83% of SHFM3 patients and 96% of literature cases; P = 0.0808). CONCLUSIONS: Patients with TPT/split foot may in fact represent SHFM3 cases and should be evaluated for genomic rearrangements at 10q24. TPT may be identified only by radiographic analysis, emphasizing the importance of imaging these patients and their family members. Birth Defects Research (Part A) 2007. © 2006 Wiley‐Liss, Inc.
Configurations of Nickel–Cyclam Antiviral Complexes and Protein Recognition
Authors: Hunter Tina M. , McNae Iain W. , Simpson Daniel P. , Smith Alison M. , Moggach Stephen , White Fraser , Walkinshaw Malcolm D. , Parsons Simon , Sadler Peter J. 
Published: November 2006

AbstractNickel(II)–xylylbicyclam is a potent anti‐HIV agent and binds strongly to the CXCR4 co‐receptor. We have investigated configurational equilibria of NiII–cyclam derivatives, since these are important for receptor recognition. Crystallographic studies show that bothtransandcisconfigurations are readily formed: [Ni(cyclam)(OAc)2]⋅H2O adopts thetrans‐III configuration with axial monodentate acetates, as does [Ni(benzylcyclam)(NO3)2] with axial nitrate ligands, whereas [Ni(benzylcyclam)(OAc)](OAc)⋅2 H2O has an unusual foldedcis‐V configuration with NiIIcoordination to bidentate acetate. UV/Vis and NMR studies show that the octahedraltrans‐III configuration slowly converts to square‐planartrans‐I in aqueous solution. For NiII–xylylbicyclam, a mixture ofcis‐V andtrans‐I configurations was detected in solution. X‐ray diffraction studies showed that crystals of lysozyme soaked in NiII–cyclam or NiII2–xylylbicyclam contain two major binding sites, one involving NiIIcoordination to Asp101 and hydrophobic interactions between the cyclam ring and Trp62 and Trp63, and the second hydrophobic interactions with Trp123. For NiII–cyclam bound to Asp101, thecis‐V configuration predominates.
The burden of fatigue and quality of life in myeloproliferative disorders (MPDs)
Authors: Mesa Ruben A. , Niblack Joyce , Wadleigh Martha , Verstovsek Srdan , Camoriano John , Barnes Sunni , Tan Angelina D. , Atherton Pamela J. , Sloan Jeff A. , Tefferi Ayalew 
Published: November 2006

AbstractBACKGROUND.Few objective data exist on the burden of fatigue and other constitutional symptoms in patients with myeloproliferative disorders (MPD).METHODS.The authors used validated instruments of fatigue and physical activity assessment during an Internet‐based symptom survey of 1179 MPD patients (median age, 56 years; 41.4% men).RESULTS.The frequency of self‐reporting was 80.7% for fatigue, which was substantially higher than that of pruritus (52.2%), night sweats (49.2%), bone pain (43.9%), fever (13.7%), and weight loss (13.1%). In the majority of patients, these symptoms restricted participation in both social functions and physical activity. In addition, 34.5% of patients needed assistance with activities of daily living, and 11.2% reported MPD‐associated medical disability. As expected, the presence of myelofibrosis, anemia, splenomegaly, or other features associated with advanced disease favored a higher degree of fatigue. However, fatigue remained the major complaint also in polycythemia vera (84.9%) and essential thrombocythemia (72.4%); these figures were significantly higher than those of published controls (P < .0001).CONCLUSIONS.The current study identifies fatigue as the major contributor to poor quality of life in MPD, provides baseline information on constitutional symptoms, and underscores the need for the incorporation of quality of life assessment in clinical trials. Cancer 2007. © 2006 American Cancer Society.
Adult neurogenesis: A common strategy across diverse species
Authors: Sullivan Jeremy M. , Benton Jeanne L. , Sandeman David C. , Beltz Barbara S. 
Published: November 2006

AbstractAdult neurogenesis, the generation of new neurons from adult precursor cells, occurs in the brains of a phylogenetically diverse array of animals. In the higher (amniotic) vertebrates, these precursor cells are glial cells that reside within specialized regions, known as neurogenic niches, the elements of which both support and regulate neurogenesis. The in vivo identity and location of the precursor cells responsible for adult neurogenesis in nonvertebrate taxa, however, remain largely unknown. Among the invertebrates, adult neurogenesis has been particularly well characterized in freshwater crayfish (Arthropoda, Crustacea), although the identity of the precursor cells sustaining continuous neuronal proliferation in these animals has yet to be established. Here we provide evidence suggesting that, as in the higher vertebrates, the precursor cells maintaining adult neurogenesis in the crayfish Procambarus clarkii are glial cells. These precursor cells reside within a specialized region, or niche, on the ventral surface of the brain, and their progeny migrate from this niche along glial fibers and then proliferate to form new neurons in the central olfactory pathway. The niche in which these precursor cells reside has many features in common with the neurogenic niches of higher vertebrates. These commonalities include: glial cells functioning as both precursor and support cells, directed migration, close association with the brain vasculature, and specialized basal laminae. The cellular machinery maintaining adult neurogenesis appears, therefore, to be shared by widely disparate taxa. These extensive structural and functional parallels suggest a common strategy for the generation of new neurons in adult brains. J. Comp. Neurol. 500:574–584, 2007. © 2006 Wiley‐Liss, Inc.
Effect of energy transfer conditions on the chemical degradation of frying oil
Authors: Achir Nawel , Kara Wassila , Chipeaux Christophe , Trezzani Isabelle , Cuvelier Marie Elisabeth 
Published: November 2006

AbstractThe effects of temperature, heating time (continuous or discontinuous mode), and water steam on sunflower oil deterioration have been investigated. Oil was heated at three temperatures, 120, 150, and 190 °C, during a total period of 60 h to achieve a wide range of degradation degrees. At 190 °C, 9 h of discontinuous heating were achieved, and oil degradation was compared to the previous treatment. Water steam treatment was investigated at two oil temperatures, 120 and 150 °C, by frying food model samples that provided a vapor flow of 1.2 g/min during about 30 h. Energy consumptions of the fryers have been measured for each experiment. Thermooxidative degradation of heated oils was evaluated by the measurement of conjugated dienes, viscosity and total polar compounds. All these indicators showed that for the same heating time, oil degradation was more important at 190 °C, and most of all for an intermittent heating. However, the results showed a good correlation between oil degradation and the fryer energy consumption for all the heating experiments, continuous or discontinuous. The presence of water seemed to modify this correlation. These results highlight the complexity of oil degradation during frying, depending on oil temperature, heating mode and presence of water, which can be expressed in energy consumption.
Bound volatile compounds and essential oil from the fruit of Maclura pomifera (Raf.) Schneid. (osage orange)
Authors: Jerkovic Igor , Mastelic Josip , Marijanovic Zvonimir 
Published: November 2006

AbstractThe bound and free volatile compounds from Maclura pomifera (Raf.) Schneid. (osage orange fruit) have been studied by GC and GC–MS. The free volatiles amounted to 230 mg/kg and the content of bound volatiles was 10 mg/kg. Identified compounds consist of aliphatic constituents (free, 28.3%; bound, 27.6%), phenylpropane derivatives along with related compounds (free, 5.1%; bound, 36.0%), monoterpenes along with sesquiterpenes (free, 54.9%; bound, 15.5%) and other compounds (bound, 1.6%). In total, 39 bound volatiles were identified, with eugenol (9.9%) and p‐cresol (9.6%) being the major components. As far as we know, this is the first report on bound volatiles of osage orange fruit and 12 compounds were established to be identical by comparison with the free volatiles. The principal constituents of the essential oil were elemol (19.2%), 1‐dodecanol (9.7%), trans‐caryophyllene (5.6%) and n‐hexyl hexanoate (5.4%). Copyright © 2006 John Wiley & Sons, Ltd.
Simple methods for assessing haplotype‐environment interactions in case‐only and case‐control studies
Authors: Kwee L.C. , Epstein M.P. , Manatunga A.K. , Duncan R. , Allen A.S. , Satten G.A. 
Published: November 2006

AbstractFor investigating haplotype‐environment interactions in case‐control studies, one can implement statistical methods based either on a retrospective likelihood (modeling the probability of haplotype and environment conditional on disease status) or a prospective likelihood (modeling the probability of disease status conditional on haplotype and environment). Retrospective approaches are generally more powerful than prospective approaches, but require an explicit model of the joint distribution of haplotype and environmental factors in the sample with the latter being particularly unattractive to specify. To resolve this issue, we propose a number of simple retrospective procedures for haplotype‐environment interaction analysis that do not require explicit modeling of environmental covariates in the sample. We first consider a cases‐only procedure, followed by a simple likelihood for case‐control data that is proportional to the full‐retrospective likelihood. Finally, we consider a retrospective procedure for inference on haplotype‐environment interaction effects in matched or finely‐stratified case‐control studies. Our methods are based on the assumptions that haplotypes and environmental covariates are independent in the target population and that disease is rare. We illustrate our approaches using case‐control data from the Finland‐United States Investigation of Non‐Insulin Dependent Diabetes Mellitus (FUSION) genetic study and simulated data. Genet. Epidemiol. © 2006 Wiley‐Liss, Inc.
Glutamate activates c‐fos in glial cells via a novel mechanism involving the glutamate receptor subtype mGlu5 and the transcriptional repressor DREAM
Authors: Edling Ylva , Ingelman‐Sundberg Magnus , Simi Anastasia 
Published: November 2006

AbstractActivation of c‐fos in brain is related to coupling of neuronal activity to gene expression, but also to pathological conditions such as seizures or excitotoxicity‐induced cell death. Glutamate activates c‐fos in neurons through the calcium‐dependent phosphorylation of CREB by ERK and/or CaMKIV kinase pathways downstream NMDA‐receptors. In glial cells, however, the activation of c‐fos by glutamate is poorly understood. Because glial cells actively modulate neuronal excitability and the brain's response to injury, we studied the mechanisms by which glutamate activates c‐fos in rat cortical glial cells. Glutamate potently induced c‐fos mRNA in a calcium‐dependent manner, as demonstrated by using the calcium chelator BAPTA‐AM. Glutamate‐induced c‐fos mRNA expression was not sensitive to inhibitors of ERK, p38MAPK, or CaMK pathways, indicating that glial c‐fos is activated by a distinct mechanism. Thapsigargin abolished the glutamate effect on c‐fos mRNA, indicating ER calcium mobilization. Additionally, glutamate induction of c‐fos mRNA was sensitive to the mGluR5 antagonist MPEP but not the NMDA‐R antagonist MK‐801. In luciferase reporter assays, DRE, which actively represses c‐fos by binding the calcium‐binding transcriptional repressor DREAM, was activated by glutamate, whereas SRE and CRE were not. Finally, glutamate caused the nuclear export of DREAM in astrocytes, and transfection of astrocytes with a mutant variant of DREAM that constitutively binds DNA inhibited glutamate‐induced c‐Fos expression. These findings are in sharp contrast to the mechanism described in neurons and suggest a novel pathway activated by glutamate in glial cells that employs mGluR5, ER calcium, and the derepression of c‐fos at the DRE. © 2006 Wiley‐Liss, Inc.
High‐involvement work practices and analysts' forecasts of corporate earnings
Authors: Benson George S. , Young Susan M. , Lawler III Edward E. 
Published: November 2006

AbstractResearch has shown that high‐involvement work practices are positively related to corporate financial performance. However, it is unknown if investors are able to use information on high‐involvement practices to predict the performance of specific companies. In this study, we examine earnings forecasts for a sample of Fortune 1000 firms and find professional stock analysts consistently underestimated the earnings of firms that made greater use of high‐involvement practices during the 1990s. Based on data collected from newspaper articles and annual reports, we argue that these lower estimates resulted from a lack of information on innovative HR practices. Recommendations to managers for disseminating information on and leveraging highinvolvement HR practices are discussed. © 2006 Wiley Periodicals, Inc.