bluuebunny/crossref_metadata_2025_split huggingface dataset:
UV accelerated aging and aging resistance of dihydroxy poly(p‐phenylene benzobisoxazole) fibers
Authors: Zhang Tao , Jin Junhong , Yang Shenglin , Li Guang , Jiang Jianming 
Published: November 2009

AbstractBy introducing binary hydroxyl groups into poly(p‐phenylene benzoxazole) (PBO) macromolecular chains, we synthesized dihydroxy poly(p‐phenylene benzobisoxazole) (DHPBO) polymers and then prepared DHPBO fibers by dry‐jet wet‐spinning. Comparative studies were performed between intrinsic PBO fibers and DHPBO fibers. The effects of hydroxyl polar groups on improving the UV aging resistance of PBO fibers were investigated. With the introduction of hydroxyl groups, substantial changes in the chemical structures and surface morphologies of DHPBO fibers were observed. As proved by tensile testing and intrinsic viscosity measurement, the UV resistance of DHPBO fibers is obviously improved compared to that of intrinsic PBO fibers. XRD results indicate that the UV aging of these fibers occurs mainly on the surfaces of fibers. Based on these results, the mechanism of UV aging of PBO fibers was discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Sequence analysis of glycolide and p‐dioxanone copolymers
Authors: Rodríguez‐galán A. , Franco L. , Puiggalí J. 
Published: November 2009

AbstractLow and medium molecular weight copolymers constituted by glycolide and p‐dioxanone units have been synthesized by a ring‐opening polymerization. The p‐dioxanone monomer was obtained from (2‐hydroxyethoxy)acetate or by thermal depolymerization of poly(p‐dioxanone). 1H and 13C NMR spectra were highly sensitive to the chemical sequences, which were effectively assigned by considering the data from samples with different compositions, and the acquisition of heteronuclear 1H and 13C NMR‐correlated spectra. End groups were also identified, allowing methylene protons of sequences involving up to two glycolide units to be distinguished. These data seem basic to analyze degradation products or the influence of thermal treatments in chain microstructure. Glycolide/p‐dioxanone copolymers are an interesting system because changes on chemical sequences can easily occur due to a depolymerization reaction that eliminates p‐dioxanone residues. Furthermore, depending on the polymerization conditions, the occurrence of transesterification reactions may be highly significant. These reactions have a great impact in properties such as the melting temperature and can be easily quantified by NMR spectroscopy because of the occurrence of a new chemical sequence. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Study of amino ligands fixation to macroporous supports and their influence on albumin adsorption
Authors: Gomez Cesar G. , Strumia Miriam C. 
Published: November 2009

AbstractHeterogeneous networks of ethylene glycol dimethacrylate and 2‐hydroxyethyl methacrylate [poly(EGDMA‐co‐HEMA)] were synthesized by suspension polymerization using different EGDMA contents and agitation speeds. The networks were actived with epichlorhydrine (Ech) or 1,4‐butanediol diglycidyl ether (BDGE), and then hexamethylenediamine (HMDA) or ethylenediamine (EDA) were conjugated to the support by coupling reaction. Here, a higher alkyldiamine concentration and temperature, and a longer reaction time led to higher yields. Amino ligands of the support III were used to analyze their adsorption performance of bovine serum albumin (BSA) from the adsorption kinetic. A more external location of HMDA amino ligands into network led to get the maximum adsorption in a time shorter than that with EDA. Due to its bigger size, the HMDA molecule was attached mostly to the network surface between larger pores, which favored a faster protein adsorption. When derivatives containing BDGE were compared, the EDA ligand displayed a BSA retention higher than that with HMDA, because a shorter separation between the ammonium groups along the spacer arm yielded a stronger electrostatic attraction on the protein. Clearly, the balance obtained between the pores system and the reagents molecular structure used in the formation of Ech‐HMDA generated the most efficient BSA adsorption. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Synthesis and kinetic analysis of DPE controlled radical polymerization of MMA
Authors: Luo Ying‐Da , Chiu Wen‐Yen 
Published: November 2009

AbstractThe 1,1‐diphenylethene (DPE) controlled radical polymerization of methyl methacrylate was performed at 80 °C by using AIBN as an initiator and DPE as a control agent. It was found that the molecular weight of polymer remained constant with monomer conversion throughout the polymerization regardless of the amounts of DPE and initiator in formulation. To understand the result of constant molecular weight of living polymers in DPE controlled radical polymerization, a living kinetic model was established in this research to evaluate all the rate constants involved in the DPE mechanism. The rate constant k2, corresponding to the reactivation reaction of the DPE capped dormant chains, was found to be very small at 80 °C (1 × 10−5 s−1), that accounted for the result of constant molecular weight of polymers throughout the polymerization, analogous to a traditional free radical polymerization system that polymer chains were terminated by chain transfer. The polydispersity index (PDI) of living polymers was well controlled <1.5. The low PDI of obtained living polymers was due to the fact that the rate of growing chains capped by DPE was comparable with the rate of propagation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Functional and tuneable amino acid polymers prepared by RAFT polymerization
Authors: Evans Amanda C. , Skey Jared , Wright Megan , Qu Wenjun , Ondeck Courtney , Longbottom Deborah A. , O'Reilly Rachel K. 
Published: November 2009

AbstractWe report the application of reversible addition‐fragmentation chain transfer polymerization using a novel chain transfer agent toward the synthesis of a variety of copolymers containing proline‐derived monomeric units. This methodology enables ready access to a number of polymeric species with narrow molecular weight distributions, reliable functional unit incorporations, and high conversions. The methodology is also a facile approach to novel copolymeric species incorporating amino acids, which possess unique material properties and the potential for further organocatalytic application. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Synthesis of thermo‐responsive 4‐arm star‐shaped porphyrin‐centered poly(N,N‐diethylacrylamide) via reversible addition‐fragmentation chain transfer radical polymerization
Authors: Yusa Shin‐Ichi , Endo Tastuya , Ito Masanori 
Published: November 2009

AbstractTetrafunctional porphyrins‐containing trithiocarbonate groups were synthesized by an ordinary esterification method. This tetrafunctional porphyrin (TPP‐CTA) could be used as a chain transfer agent in a controlled reversible addition‐fragmentation chain transfer (RAFT) radical polymerization to prepare well‐defined 4‐arm star‐shaped polymers. N,N‐Diethylacrylamide was polymerized using TPP‐CTA in 1,4‐dioxane. Poly(N,N‐diethylacrylamide) (PDEA) is known to be a thermo‐responsive polymer, and exhibits a lower critical solution temperature (LCST) in water. The star‐shaped PDEA polymer (TPP‐PDEA) was therefore also thermo‐responsive, as expected. The LCST of this polymer depended on its concentration in water, as confirmed by turbidity, dynamic light scattering (DLS), static light scattering (SLS), and 1H NMR measurements. The porphyrin cores were compartmentalized in PDEA shells in aqueous media. Below the LCST, the fluorescence intensity of TPP‐PDEA was about six times larger than that of a water‐soluble low molecular weight porphyrin compound (TSPP), whose fluorescence intensity was independent of temperature. Above the LCST, the fluorescence intensity of TPP‐PDEA decreased, while the intensity was about three times higher than that of TSPP. These observations suggested that interpolymer aggregation occurred due to the hydrophobic interactions of the dehydrated PDEA arm chains above the LCST, with self‐quenching of the porphyrin moieties arising from these interactions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Synthesis of hyperbranched degradable polymers by atom transfer radical (Co)polymerization of inimers with ester or disulfide groups
Authors: Tsarevsky Nicolay V. , Huang Jinyu , Matyjaszewski Krzysztof 
Published: November 2009

AbstractDegradable hyperbranched polymers with multiple alkyl halide chain ends were synthesized by the atom transfer radical polymerization of inimers containing ester (2‐(2′‐bromopropionyloxy)ethyl acrylate) or disulfide (2‐(2′‐bromoisobutyryloxy)ethyl 2′′‐methacryloyloxyethyl disulfide) groups. Both the homo‐ and copolymerizations (with styrene in the former case and methyl methacrylate in the latter) were studied. The hyperbranched polymers derived from the ester‐type inimer were hydrolytically degradable under basic conditions, whereas those derived from the disulfide‐containing inimer could be efficiently degraded in the presence of reducing agents such as tributylphosphine. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Organic–inorganic hybrid brushes consisting of macrocyclic oligomeric silsesquioxane and poly(ε‐caprolactone): Synthesis, characterization, and supramolecular inclusion complexation with α‐cyclodextrin
Authors: Han Jin , Zheng Sixun 
Published: November 2009

AbstractOrganic–inorganic hybrid brushes comprised of macrocyclic oligomeric silsesquioxane (MOSS) and poly(ε‐caprolactone) (PCL) were synthesized via the ring‐opening polymerization of ε‐caprolactone (CL) with cis‐hexa[(phenyl) (2‐hydroxyethylthioethyldimethylsiloxy)]cyclohexasiloxane as the initiator. The MOSS macromer bearing hydroxyl groups was synthesized via the thiol‐ene radical addition reaction between cis‐hexa[(phenyl)(vinyldimethylsiloxy)]cyclohexasiloxane and β‐mercaptoethanol. The organic–inorganic PCL cyclic brushes were characterized by means of nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). These MOSS–PCL brushes were then used to prepare the supramolecular inclusion complexes with α‐cyclodextrin (α‐CD). The X‐ray diffraction (XRD) indicates that the organic–inorganic inclusion complexes (ICs) have a channel‐type crystalline structure. It is noted that the molar ratios of CL unit to α‐CD for the organic–inorganic ICs are quite dependent on the lengths of the PCL chains bonded to the silsesquioxane macrocycle. While the PCL chains were short, the efficiency of inclusion complexation was significantly decreased. The decreased efficiency could be attributed to the repulsion of the adjacent PCL chains bonded to the silsesquioxane macrocycle and the restriction of the bulky silsesquioxane macrocycle on the motion of PCL chains; this effect is pronounced with decreasing the length of the PCL chains. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Importance measures for modular software with uncertain parameters
Authors: Fiondella Lance N. , Gokhale Swapna S. 
Published: November 2009

AbstractImportance measures provide a sense of the relative priorities of components and can be used to guide the allocation of resources for cost‐effective improvement of system reliability starting from the early phases. Uncertainties in model parameters, prevalent in the early phases, can introduce errors into these measures, and hence, importance assessment must account for these parametric uncertainties. In this paper, a framework for importance assessment of a software system within the context of its architecture is proposed. The framework includes two methods; the first one systematically quantifies the confidence intervals in the model parameters, and the second one offers an analytical approach for importance analysis. The two methods in conjunction address the issue of importance assessment in the face of parametric uncertainties. Illustration of the framework using a banking application demonstrates the value and benefits of the methodology. Copyright © 2009 John Wiley & Sons, Ltd.
Does the prospect theory also hold for power traders? Empirical evidence from a Swiss energy company
Authors: Kalayci Erkan , Basdas Ulkem 
Published: November 2009

AbstractCurrently, a great deal of empirical research has been done to test and verify Kahneman and Tversky's (1979) prospect theory. Nevertheless, the research only addresses private or institutional investors in the financial industry and has neglected specific tests in the real sector. In this paper, our goal is to examine whether the implications of prospect theory and the house money effect also hold for the power traders in the energy sector. The results show that the reflection and house money effects do not hold. Our results indicate the possible influence of the recent global crisis on prospect theory.
ON LEGENDRE CURVES IN CONTACT PSEUDO-HERMITIAN 3-MANIFOLDS
Authors: LEE JI-EUN 
Published: November 2009

AbstractWe find necessary and sufficient conditions for a Legendre curve in a Sasakian manifold to have: (i) a pseudo-Hermitian parallel mean curvature vector field; (ii) a pseudo-Hermitian proper mean curvature vector field in the normal bundle.
Effect of dark chocolate on plasma epicatechin levels, DNA resistance to oxidative stress and total antioxidant activity in healthy subjects
Authors: Spadafranca A. , Martinez Conesa C. , Sirini S. , Testolin G. 
Published: November 2009

Dark chocolate (DC) may be cardioprotective by antioxidant properties of flavonoids. We investigated the effect of DC (860 mg polyphenols, of which 58 mg epicatechin) compared with white chocolate (WC; 5 mg polyphenols, undetectable epicatechin) on plasma epicatechin levels, mononuclear blood cells (MNBC) DNA damage and plasma total antioxidant activity (TAA). Twenty healthy subjects followed a balanced diet (55 % of energy from carbohydrates, 30 % from fat and 1 g protein/kg body weight) for 4 weeks. Since the 14th day until the 27th day, they introduced daily 45 g of either WC (n10) or DC (n10). Whole experimental period was standardised in antioxidant intake. Blood samples were collected at T0, after 2 weeks (T14), 2 h and 22 h after the first chocolate intake (T14+2 hand T14+22 h), and at 27th day, before chocolate intake (T27), 2 h and 22 h after (T27+2 hand T27+22 h). Samples, except for T14+2 hand T27+2 h, were fasting collected. Detectable epicatechin levels were observed exclusively 2 h after DC intake (T14+2 h = 0·362 (se0·052) μmol/l and T27+2 h = 0·369 (se0·041) μmol/l); at the same times corresponded lower MNBC DNA damages (T14+2 h = − 19·4 (se3·4) %v.T14,P < 0·05; T27+2 h = − 24 (se7·4) %v.T27,P < 0·05; T14+2 hv.T27+2 h,P = 0·7). Both effects were no longer evident after 22 h. No effect was observed on TAA. WC did not affect any variable. DC may transiently improve DNA resistance to oxidative stress, probably for flavonoid kinetics.
Changing the zinc:iron ratio in a cereal-based nutritional supplement has no effect on percent absorption of iron and zinc in Sri Lankan children
Authors: Hettiarachchi Manjula , Liyanage Chandrani , Hilmers David , Griffin Ian , Abrams Steven A. 
Published: November 2009

The Thriposha programme is a community-level nutrition intervention in Sri Lanka that provides a combination of energy, protein and micronutrients as a ‘ready-to-eat’ cereal-based food. We measured the bioavailability of Fe and Zn from Thriposha formula at two different molar ratios of Zn:Fe in order to determine the effect on Fe and Zn absorption. Children 4–7 years (n53) were given a meal prepared with 50 g Thriposha containing 1·5 mg Zn as zinc sulphate and either 9 mg (high Fe concentration (HiFe)) or 4·5 mg (low Fe concentration (LoFe)) Fe as ferrous fumarate. Zn and Fe percent absorption were measured using stable isotopes by tracer:tracee ratio and by incorporation of erythrocytes, respectively. Percent Fe absorption from the two meals was similar (6·6 % (4·8)v. 4·8 % (2·6);P = 0·15), but total Fe absorption was significantly higher from the HiFe meal (0·59 (0·43) mg) than the LoFe meal (0·20 (0·12) mg;P = 0·01). There was no significant difference between the two groups in Zn absorption (10·7 % (0·9)v. 8·8 % (1·4),P = 0·13, respectively). Decreasing the amount of Fe in Thriposha did not cause a significant change in the percent absorption of Fe and Zn, but significantly lowered the total amount of absorbed Fe. These results demonstrate the utility of maintaining a higher Fe content in this supplement. Further studies to increase Zn content are warranted while maintaining a HiFe.
Childhood overweight and obesity among Kenyan pre-school children: association with maternal and early child nutritional factors
Authors: Gewa Constance A 
Published: November 2009

AbstractObjectiveTo report on the prevalence of overweight and obesity among pre-school children in Kenya and examine the associations between childhood overweight and selected maternal and child-related factors.DesignDemographic Health Survey data, multistage stratified cluster sampling methodology.SettingRural and urban areas of Kenya.SubjectsA total of 1495 children between the ages of 3 and 5 years in Kenya.ResultsOver 30 % of the children were stunted, approximately 16 % were underweight, 4 % were wasted, approximately 18 % were overweight and 4 % were obese; 8 % were both overweight/obese and stunted. Maternal overweight and obesity, higher levels of maternal education, being a large or very large child at birth, and being stunted were each associated with higher odds of overweight and obesity among Kenyan children. Older children and large household size were each associated with lower odds of overweight and obesity among Kenyan children.ConclusionsThe analysis demonstrates the presence of under- and overnutrition among Kenyan pre-school children and the importance of focusing on expanding efforts to prevent and treat malnutrition within this population. It also identifies some of the modifiable factors that can be targeted in these efforts.
ARH: predicting splice variants from genome-wide data with modified entropy
Authors: Rasche Axel , Herwig Ralf 
Published: November 2009

Abstract
Motivation: Exon arrays allow the quantitative study of alternative splicing (AS) on a genome-wide scale. A variety of splicing prediction methods has been proposed for Affymetrix exon arrays mainly focusing on geometric correlation measures or analysis of variance. In this article, we introduce an information theoretic concept that is based on modification of the well-known entropy function.
Results: We have developed an AS robust prediction method based on entropy (ARH). We can show that this measure copes with bias inherent in the analysis of AS such as the dependency of prediction performance on the number of exons or variable exon expression. In order to judge the performance of ARH, we have compared it with eight existing splicing prediction methods using experimental benchmark data and demonstrate that ARH is a well-performing new method for the prediction of splice variants.
Availability and Implementation: ARH is implemented in R and provided in the Supplementary Material.
Contact: rasche@molgen.mpg.de
Supplementary information: Supplementary data are available at Bioinformatics online.
Modeling the interplay of single-stranded binding proteins and nucleic acid secondary structure
Authors: Forties Robert A. , Bundschuh Ralf 
Published: November 2009

Abstract
Motivation: There are many important proteins which bind single-stranded nucleic acids, such as the nucleocapsid protein in HIV and the RecA DNA repair protein in bacteria. The presence of such proteins can strongly alter the secondary structure of the nucleic acid molecules. Therefore, accurate modeling of the interaction between single-stranded nucleic acids and such proteins is essential to fully understand many biological processes.
Results: We develop a model for predicting nucleic acid secondary structure in the presence of single-stranded binding proteins, and implement it as an extension of the Vienna RNA Package. All parameters needed to model nucleic acid secondary structures in the absence of proteins have been previously determined. This leaves the footprint and sequence-dependent binding affinity of the protein as adjustable parameters of our model. Using this model we are able to predict the probability of the protein binding at any position in the nucleic acid sequence, the impact of the protein on nucleic acid base pairing, the end-to-end distance distribution for the nucleic acid and FRET distributions for fluorophores attached to the nucleic acid.
Availability: Source code for our modified version of the Vienna RNA package is freely available at http://bioserv.mps.ohio-state.edu/Vienna+P, implemented in C and running on Linux.
Contact: bundschuh@mps.ohio-state.edu
First Report of a Root and Crown Disease Caused by Rhizoctonia solani on Centaurea stoebe in Russia
Authors: Caesar A. J. , Lartey R. T. , Caesar-TonThat T. 
Published: November 2009

Spotted knapweed (SKW), Centaurea stoebe L., is a nonindigenous species that is invasive over large areas in the United States, especially in the west. It has been estimated that infestations of SKW cause $42 million in direct and indirect economic losses annually (2), and the weed could potentially invade 13.6 million ha of rangeland in Montana alone. Extensive efforts toward the control of SKW have included the release of 12 insects for biological control, four of which attack the crowns and roots of this short-lived perennial. To focus efforts to select potential soilborne pathogens, which could be applied in combination with insects, we conducted a survey for plant pathogens in the native range of SKW associated with damage caused by any root-attacking insects. Stunted and chlorotic SKW plants, which were colonized by larvae of Cyphocleonus spp., were found in June 1994 near the Novomar'evskaya Botanical Sanctuary (45°08′49.87″N, 41°51′02.05″E) in the Caucasus Region of Russia. A nonsporulating multinucleate fungus was isolated from the lower stem, crown, and upper root tissue of one such plant. Colonies growing on potato dextrose agar and Ko and Hora media were examined microscopically and identified as Rhizoctonia solani by the occurrence of robust, thick-walled, golden hyphae with right-angled branching and constrictions at the branch points. The anastomosis grouping of the one isolate was determined to be AG 2-2 IIIB after pairing it on water agar with 11 AG tester isolates representing all subgroups of AG 1 to AG 5. The hyphal diameter at the obvious point of anastomosis was reduced and cell death of adjacent cells was observed. In 2007, pathogenicity was determined by planting 12-week-old seedlings of SKW, one per pot, into 20 15-cm-diameter pots of a steamed greenhouse soil mix composed of sphagnum peat, sand, and Bozeman silt loam (1:1:1, vol/vol), pH 6.6, infested with R. solani-colonized barley grain that had been dried and milled. An inoculum level of 8 CFU/g of air-dried soil was determined by most probable number calculations from fourfold dilutions of infested soil. Controls were planted into noninfested soil. In both greenhouse tests, the isolate caused either mortality or a 93% mean fresh weight reduction of surviving plants, relative to the controls, after 8 months. R. solani was reisolated from necrotic root and crown tissue of dead and stunted plants but not from the controls. To our knowledge, this is the first report of R. solani occurring on SKW in Europe. The characterization and pathogenicity of Fusarium spp. isolated from insect-colonized roots of SKW in Europe was reported previously (1). References: (1) A. J. Caesar et al. BioControl 47:217. (2) S. A. Hirsch and J. A. Leitch, North Dakota Agricultural Economics Report No. 355. NDSU, Fargo. 1996.