bluuebunny/crossref_metadata_2025_split huggingface dataset:
First phase insulin release and glucose tolerance in children with Fanconi anemia after hematopoietic cell transplantation
Authors: Polgreen Lynda E. , Thomas William , MacMillan Margaret L. , Wagner John E. , Moran Antoinette , Petryk Anna 
Published: April 2009

AbstractBackgroundFanconi anemia (FA) is an autosomal and X‐linked recessive disease of chromosomal instability, which results in bone marrow failure. Children with FA have been shown to have an increased risk of diabetes mellitus (DM).ProcedureA cross‐sectional study of glucose and insulin metabolism was conducted in 17 children with FA who had undergone hematopoietic cell transplantation (HCT) at the University of Minnesota. First phase insulin release (FPIR) was determined by intravenous glucose tolerance test (IVGTT). Oral glucose tolerance test (OGTT), lipid panel, blood pressure, and medical history were reviewed for additional metabolic abnormalities.ResultsSeventeen FA participants, median age 11.3 (range 5.5–17.6) years, were evaluated. IVGTT identified three separate groups: low FPIR, normal FPIR, and high FPIR. Those with low FPIR were more likely to have low BMI, but had normal glucose levels. Those with high FPIR, had high BMI, elevated lipids, and body fat. One patient with normal FPIR had impaired glucose tolerance and another with normal FPIR had impaired fasting glucose. No participant was diagnosed with DM by fasting glucose, 2 hr glucose during OGTT, or hemoglobin A1C.ConclusionsThe majority of children with FA had normal glucose tolerance and normal beta‐cell function after HCT. Two small subsets of patients had lower than expected and higher than expected FPIR. The clinical significance of these differences is not yet known given the normal glucose tolerance and fasting glucose levels in these two groups. Pediatr Blood Cancer 2009;53:191–196. © 2009 Wiley‐Liss, Inc.
Tribological properties of LDPE + Boehmite composites
Authors: Brostow Witold , Datashvili Tea , Kao David , Too Jonathan 
Published: April 2009

AbstractTribological properties of composites of low density polyethylene (LDPE) reinforced with 1, 5, 10, 20 wt% micrometric Boehmite (B) and/or preheated Boehmite (HB) powders were studied in combination with two silane coupling agents (SCAs): vinyltri(2‐methoxyethoxy)‐silane (VTMES)‐SCA 972 and 3‐(trimethoxysilyl)‐propylmethacrylate (3MPS)‐SCA 989. When coupling agents are used, the samples not subjected to preheating provide higher yields of grafting and more bonds introduced on surfaces of Boehmite particles than heated ones. We have determined sliding wear by multiple scratching along the same groove using a micro scratch tester. Instantaneous penetration depth is lowered by the filler addition to LDPE. However, there is less viscoelastic recovery and the residual (healing) depths increase with increasing Boehmite concentration. Friction was determined using a pin‐on‐disk tribometer and also a moving sled friction device. Addition of 20 wt% untreated B and/or HB particles to LDPE matrix reduces friction. However, a more significant improvement of tribological properties results from incorporation of grafted particles; this occurs because of an increase of the filler/matrix interfacial adhesion. Surface morphology seen in scanning electron microscopy confirms this explanation. Friction values for all samples decrease along with the filler concentration increase. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Synthesis and characterization of short Grewia optiva fiber‐based polymer composites
Authors: Singha Amar S. , Thakur Vijay Kumar 
Published: April 2009

AbstractNatural fibers, such as Flax, Sisal, Hibiscus Sabdariffa, and Grewia optiva (GO) possess good reinforcing capability when properly compounded with polymers. These fibers are relatively inexpensive, easily available from renewable resources, and possess favorable values of specific strength and specific modulus. The mechanical performance of natural fiber‐reinforced polymers (FRPs) is often limited owing to a weak fiber‐ matrix interface. In contrast, urea–formaldehyde (UF) resins are well known to have a strong adhesion to most cellulose‐containing materials. This article deals with the synthesis of short G. optiva fiber‐reinforced UF polymer matrix‐based composites. G. optiva fiber‐reinforced UF composites processed by compression molding have been studied by evaluating their mechanical, physical, and chemical properties. This work reveals that mechanical properties such as: tensile strength, compressive strength, flexural strength, and wear resistance of the UF matrix increase up to 30% fiber loading and then decreases for higher loading when fibers are incorporated into the polymer matrix. Morphological and thermal studies of the matrix, fiber, and short FRP composites have also been carried out. The swelling, moisture absorbance, chemical resistance, and water uptake behavior of these composites have also been carried out at different intervals. The results obtained lay emphasis on the utilization of these fibers, as potential reinforcing materials in bio‐based polymer composites. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Effect of both silane‐grafted and ion‐exchanged organophilic clay in structural, thermal, and mechanical properties of unsaturated polyester nanocomposites
Authors: Şen Sinan 
Published: April 2009

AbstractUnsaturated polyester (UPE) resin including styrene monomer was mixed with organophilic montmorillonite (MMT) clay and its crosslinking polymerization reaction was done in the presence of free‐radical initiator. MMT clay was modified with cetyl trimethly ammonium bromide and trimethoxy vinyl silane. The nanocomposites were characterized by X‐ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), thermogravimetric and dynamic mechanical analyses (TGA and DMA). The exfoliated nanocomposite structure was obtained when the MMT clay was modified in the presence of both modifiers, whereas individual modifications all resulted in intercalated structures. The exfoliated UPE nanocomposite exhibited better thermal and dynamic mechanical properties when compared with pure UPE and other composites, even with 3 wt% clay loading. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Synthesis and mechanical properties of polybenzimidazole nanocomposites reinforced by vapor grown carbon nanofibers
Authors: Zhang Li , Ni Qing‐Qing , Shiga Akihiko , Fu Yaqin , Natsuki Toshiaki 
Published: April 2009

AbstractPolybenzimidazole (PBI) nanocomposites containing 0.5–5 wt% vapor grown carbon nanofibers (VGNFs) were successfully synthesized by solvent evaporation method. Fracture morphology examination confirmed the uniform dispersion of VGNFs in the matrix. The mechanical properties of neat PBI and the nanocomposites were systematically measured by tensile test, dynamic mechanical analysis (DMA), hardness measurement, and friction test. Tensile tests revealed that Young's modulus increased by about 43.7% at 2 wt% VGNFs loading, and further modulus growth was observed at higher filler loadings. DMA studies showed that the nanocomposites have higher storage modulus than neat PBI in the temperature range of 30–350°C, holding storage modulus larger than 1.54 GPa below 300°C. Outstanding improvement of hardness was achieved for PBI upon incorporating 2 wt% of VGNFs. The results of friction test showed that coefficient of friction of PBI nanocomposites decreased with VGNFs content compared with neat PBI. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Liquid crystalline matrix polymers for aramid ballistic composites
Authors: de Ruijter C. , van der Zwaag S. , Stolze R. , Dingemans T.J. 
Published: April 2009

AbstractFive semi‐flexible thermotropic liquid crystalline (LC) polyesters and poly(ester‐amide)s were synthesized and used as matrix resins for Twaron™ aramid‐based ballistic fabrics. The ballistic performance was investigated as a function of the neat resin content. For the most successful liquid crystalline polyester system, the effect of blending with styrene‐ethylene‐butylene‐styrene (SEBS) and polyvinyl butyrate (PVB) rubber was also explored. The best neat resin V50 values were obtained for 20 wt% LC polyester (LCPE)‐Twaron™ composites, that is, 418 m.s−1, whereas SEBS/LCPE and PVB/LCPE modifications resulted in maximum V50 values of 460 and 466 m.s−1, respectively. It was found that the ballistic impact resistance is strongly influenced by the elastic modulus of the resin component and to a lesser extent to the level of adhesion between the resin and fabric. The effect of resin content, resin strength, elongation‐at‐break, and resin toughness on the ballistic impact resistance was found to be small. The best ballistic protection could be obtained when the Young's modulus of the LC resin was in the range of 0.01–1 GPa. This result seems to be in agreement with existing inter‐yarn friction models. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Kaolin–epoxy‐based nanocomposites: A complementary study of the epoxy curing by FTIR and fluorescence
Authors: Castrillo P.D. , Olmos D. , Torkelson J.M. , González‐Benito J. 
Published: April 2009

AbstractThis work is focused on the study of the effect exerted by the presence of kaolin on the cure reaction of an epoxy‐based polymer, discussing the influence of different kaolin pretreatments. During the last few years, the interest on polymer matrix nanocomposite materials has sharply increased because generally they show improved properties when compared with those of the neat polymer (without filler). Among this sort of materials, polymer clay nanocomposites have been widely studied. However, there are not many works about kaolin‐based composites. Although several techniques have been used to monitor the cure process in epoxy‐based composites such as Fourier transform infrared spectroscopy (FTIR) or differential scanning calorimetry, only the use of the fluorescent response from a fluorophore seems to be adequate to monitor the reaction exactly at the interfaces at a molecular scale. In this work, FTIR and fluorimetry were used to monitor the cure reaction of the different composite systems at different curing temperatures. The analysis of FTIR experiments revealed that the presence of the reinforcement clay affects the extent of the cure reaction depending on the nature of its surface. On the other hand, the use of a fluorescent molecule chemically bonded to the reinforcement allows studying the curing exactly at the interface. Finally, with the collected data, a kinetic analysis was done and the results obtained were compared in terms of the technique used and the information source (interface or bulk). At the interface, the activation energy for the epoxy reaction is lower than that carried out in the bulk indicating that the reaction at the interface proceeds via a particular mechanism for which the reaction is favored. It seems that a higher amount of hydroxyl groups is capable of catalyzing the cure reaction. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Toughening of polyamide 11 via addition of crystallizable polyethylene derivatives
Authors: Zhou Chengjuan , Wang Ke , Fu Qiang 
Published: April 2009

AbstractBACKGROUND: Conventional rubber‐like toughening modifiers are soft and amorphous, and when used to toughen polyamide 11 (PA11) they commonly induce a decrease in the tensile strength and modulus. In this study, crystallizable polyethylene (PE) derivatives, i.e. linear low‐density polyethylene (LLDPE) and maleic anhydride‐grafted polyethylene (PE‐g‐MA), were adopted to toughen PA11.RESULTS: Compared to pure PA11, a highest improvement by a factor of eight in the impact toughness was achieved; also, the tensile strength and modulus could be maintained at a relatively high level. PE‐g‐MA acted as a compatibilizer for PA11 and LLDPE, bringing strong interfacial adherence, and especially a domain‐in‐domain morphology observed in PA11/PE‐g‐MA/LLDPE (70/10/20 by weight) blends. The observation that PA11 was toughened by the crystallizable PE derivatives is discussed in depth, based on the combined effect of surface crystallization of LLDPE on pre‐formed PA11 crystallites and interfacial compatiblization between PA11 and PE‐g‐MA.CONCLUSION: The crystallizable PE derivatives LLDPE and PE‐g‐MA were shown to be effective toughening modifiers for the proportions PA11/PE‐g‐MA/LLDPE 70/10/20 (by weight), which is considered to be an optimum composition: special domain‐in‐domain morphology was observed indicating a good dispersion of PE in the PA11 matrix and strong interfacial adherence between PE phase and PA11 phase. The reason why strength and modulus were maintained at a high level in the as‐prepared blends was attributed to the existence of rigid crystalline domains in PE. Copyright © 2009 Society of Chemical Industry
Relationship vulnerabilities during breast cancer: patient and partner perspectives
Authors: Fergus Karen D. , Gray Ross E. 
Published: April 2009

AbstractObjective: Close interpersonal relationships play a crucial role in a woman's adjustment to breast cancer. To date, the literature has focused primarily on characteristics or behaviors of the well spouse that influence a woman's adaptation to the illness. The present qualitative investigation extended this literature by adopting an interactional perspective based on the underlying assumption that relationship partners' coping and distress is mutually influential. The focus of the analysis was patient and partner perceptions of relationship strife or tension over the course of the illness based on the notion that such interactions may be as or more harmful to relationships than supportive exchanges are helpful.Method: Nineteen women (at different stages of the illness) and eleven male spouses were interviewed about their experiences in relation to breast cancer. Nine of the men and nine of the women were relationship partners. Interview text was subjected to a thematic analysis and informed by grounded theory principles.Results: Two higher‐order categories of Personal Characteristics (both patient and partner) and Relationship Dynamics that impeded couple adjustment defined the overall theme of Relationship Vulnerabilities.Conclusions: Findings from this study are situated within a broader developmental framework wherein breast cancer is considered a catastrophic life event that challenges the assimilation and accommodation processes of both partners in the relationship. For couples that are able to overcome the relationship challenges associated with the illness, there is the potential for mutual growth, and a deepening and strengthening of the relationship. Implications for clinical practice are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Personality variables are associated with colorectal cancer patients' quality of life independent of psychological distress and disease severity
Authors: Paika Vassiliki , Almyroudi Augoustina , Tomenson Barbara , Creed Francis , Kampletsas Eleftherios O. , Siafaka Vassiliki , Gkika Styliani , Mavreas Venetsanos , Pavlidis Nicholas , Hyphantis Thomas 
Published: April 2009

AbstractObjective: The aim of the present study was to test whether psychological distress and personality variables are independently associated with health‐related quality of life (HRQOL) in colorectal cancer patients, after adjusting for age, gender, education and disease severity.Methods: In a cross‐sectional study of 162 colorectal cancer patients (response rate 65.6%), the following self‐report instruments were administered: the Symptom Distress Checklist‐90‐R, the Sense of Coherence scale, the Life Style Index and the Hostility and Direction of Hostility Questionnaire. The outcome measures were the four components of the WHO Quality of Life Instrument, Short Form. We used hierarchical regressions to determine whether psychological distress mediates the relationship of personality and disease parameters with HRQOL.Results: The overall proportion of the variance in the four components of HRQOL explained by our regression models ranged from 28.1 to 44.4%. Psychological distress was an independent correlate of HRQOL, associated with physical (p<0005), mental (p<0.05) and social relationships HRQOL (p<0.02). Personality variables were associated with HRQOL independent of psychological distress and disease severity. Sense of coherence and denial defense were positively associated with all aspects of HRQOL independent of psychological distress and disease parameters (p‐values ranging fromp<0.05 top<0.0005). Hostility (p<0.01) and repression defense (p=0.024) were also independently but negatively associated with physical HRQOL.Conclusions: In colorectal cancer patients, psychological distress is associated with HRQOL independent of disease parameters but personality variables are also associated with HRQOL independent of disease severity and psychological distress, and this could be relevant to psychological interventions. Copyright © 2009 John Wiley & Sons, Ltd.
Biophysical studies support a predicted superhelical structure with armadillo repeats for Ric‐8
Authors: Figueroa Maximiliano , Victoria Hinrichs María , Bunster Marta , Babbitt Patricia , Martinez‐Oyanedel José , Olate Juan 
Published: April 2009

AbstractRic‐8 is a highly conserved cytosolic protein (MW 63 KDa) initially identified in C. elegans as an essential factor in neurotransmitter release and asymmetric cell division. Two different isoforms have been described in mammals, Ric‐8A and Ric‐8B; each possess guanine nucleotide exchange activity (GEF) on heterotrimeric G‐proteins, but with different Gα subunits specificities. To gain insight on the mechanisms involved in Ric‐8 cellular functions it is essential to obtain some information about its structure. Therefore, the aim of this work was to create a structural model for Ric‐8. In this case, it was not possible to construct a model based on comparison with a template structure because Ric‐8 does not present sequence similarity with any other protein. Consequently, different bioinformatics approaches that include protein folding and structure prediction were used. The Ric‐8 structural model is composed of 10 armadillo folding motifs, organized in a right‐twisted α‐alpha super helix. In order to validate the structural model, a His‐tag fusion construct of Ric‐8 was expressed in E. coli, purified by affinity and anion exchange chromatography and subjected to circular dichroism analysis (CD) and thermostability studies. Ric‐8 is approximately 80% alpha helix, with a Tm of 43.1°C, consistent with an armadillo‐type structure such as α‐importin, a protein composed of 10 armadillo repeats. The proposed structural model for Ric‐8 is intriguing because armadillo proteins are known to interact with multiple partners and participate in diverse cellular functions. These results open the possibility of finding new protein partners for Ric‐8 with new cellular functions.
Racemic crystallography of synthetic protein enantiomers used to determine the X‐ray structure of plectasin by direct methods
Authors: Mandal Kalyaneswar , Pentelute Brad L. , Tereshko Valentina , Thammavongsa Vilasak , Schneewind Olaf , Kossiakoff Anthony A. , Kent Stephen B. H. 
Published: April 2009

AbstractWe describe the use of racemic crystallography to determine the X‐ray structure of the natural product plectasin, a potent antimicrobial protein recently isolated from fungus. The protein enantiomers L‐plectasin and D‐plectasin were prepared by total chemical synthesis; interestingly, L‐plectasin showed the expected antimicrobial activity, while D‐plectasin was devoid of such activity. The mirror image proteins were then used for racemic crystallization. Synchrotron X‐ray diffraction data were collected to atomic resolution from a racemic plectasin crystal; the racemate crystallized in the achiral centrosymmetric space group P1 with one L‐plectasin molecule and one D‐plectasin molecule forming the unit cell. Dimer‐like intermolecular interactions between the protein enantiomers were observed, which may account for the observed extremely low solvent content (13%–15%) and more highly ordered nature of the racemic crystals. The structure of the plectasin molecule was well defined for all 40 amino acids and was generally similar to the previously determined NMR structure, suggesting minimal impact of the crystal packing on the plectasin conformation.
Advances in self‐assembled SiGe islands and nanostructures
Authors: Baribeau J.‐M. , Wu X. 
Published: April 2009

AbstractWe review aspects in the growth and characterization of Si1–xGex islands and Ge dots on (001) Si. We discuss the mechanisms that lead to dot formation and their shape evolution with Ge coverage. We discuss recent progress in the determination of their composition and strain. We review various approaches currently being investigated to engineer Si1–xGex quantum dots and in particular control their size, density and spatial distribution. For example, we show how C pre‐deposition on Si (001) can influence nucleation and growth of Ge islands. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence of core‐shell CdSe/ZnS quantum dots of different sizes
Authors: Torchynska T. V. , Douda J. , Sierra R. Peña 
Published: April 2009

AbstractThis paper presents the results of peculiarity analysis in PL spectra of CdSe/ZnS QDs of different sizes. Commercially available CdSe/ZnS core/shell QDs characterized by emission at 525 nm (2.36 eV), 560 nm (2.22 eV), 605 nm (2.05 eV) and 640 nm (1.94 eV) have been studied. PL spectra were measured at excitation by a He‐Cd laser with the light wavelength of 325 nm at the temperatures 10 and 300K. PL spectra of different size QDs can be presented as a superposition of 3 elementary PL bands: (i) PL band deals with ground state exciton emission in a CdSe core and (ii) two PL bands (2.37 and 2.68 eV) assigned to the electron‐hole recombination via interface defects. The spectral positions of defect‐related PL bands did not change versus temperature or QD size. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microscopic local bonding and optically‐induced switching for Ge2Sb2Te5 alloys: A tale of four pseudo‐binary and three binary tie‐lines in Ge‐Sb‐Te phase field
Authors: Lucovsky G. , Baker D. A. , Washington J. P. , Paesler M. A. 
Published: April 2009

AbstractGe2Sb2Te5 (GST‐225) has emerged as an active medium for applications in reversible, ReWritable (RW) optical memory discs. Many studies have focused on the properties of this alloy, relative to the other GST compositions on tie‐lines in the Ge‐Sb‐Te ternary phase field; (i) Sb2Te to GeTe2: (ii) Sb2Te3: to GeTe; (iii) GeSb to Te: and (iv) the truncated tie‐line from GST‐124 to Sb. This article focuses instead on the binary atomic join‐lines, Te‐Ge, Ge‐Sb and Sb‐Te, that comprise the perimeter of the Ge‐Sb‐Te ternary diagram. Three eutectic compositions, one on each perimeter segment: (i) Ge12Sb88; (ii) Te25Sb75; and (iii) Ge17Te83 have been identified. Focussing on the significance of these eutectic compositions, and (i) building on previous publications from our group, and (ii) relying on two recently published articles, a new model for the RW properties of GST‐22T has been proposed. Finally comparisons are made between GST and AIST RW films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)