bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of amphiphilic graft copolymers with hydrophobic poly(α-methylstyrene) backbone and hydrophilic poly(n-vinylpyrrolidone) side chains
Authors: Sebba Fatima Zohra , Kada Seghier Ould , Benaicha Mohamed , Nemiche Nerjesse 
Published: August 2014

AbstractIn this study, 2-oxopropylmethacrylate-terminated poly(N-vinyl-2- pyrrolidone) is produced by cationic polymerization using HClO4 as an initiator. Termination (end capping) step is accomplished using 2- hydroxypropylmethacrylate (2HPMA) and the polymer product has different chain lengths of molecular weight averages ranging from 672 to 3049 g/mol. The study also synthesised amphipathic graft copolymers having hydrophobic poly(α- methylstyrene) as a backbone chain and hydrophilic poly(N-vinyl-2-pyrrolidone) (PVP) as side chains of various lengths. The copolymer synthesis was accomplished by free radical copolymerization of ω-oxopropylmethacrylate PVP in the presence of α-methyl styrene initiated with benzoyl peroxide. Measurements of the dynamic viscosity of the polymer solution (20% weight of macromonomers in ethanol) show that the viscosity is proportional to the average molecular weights M̅n . However, a reverse behaviour of the viscosity variation with regard to M̅n is observed for graft copolymer samples. The viscosity variation with respect to the graft copolymer mass must be due to steric effects, which are strongly pronounced in grafted copolymer chains. Appearance of the number of side chains attached to poly(α-methylstyrene) backbone reveals that the grafting reaction has occurred with good efficiency.
Rheological properties of pectin, poly(vinyl alcohol) and their blends in aqueous solutions
Authors: Lewandowska Katarzyna , Dąbrowska Aldona , Kaczmarek Halina 
Published: August 2014

AbstractThe new blends composed of natural polysaccharide - pectin and synthetic water soluble polymer - poly(vinyl alcohol) (PVA) are attractive materials due to their biocompatibility, non-toxicity and biodegradability. In this work the rheological properties of aqueous solutions of pectin (PEC), poly(vinyl alcohol) and their mixtures at various weight ratios (70/30, 50/50, 30/70) have been investigated. Flow measurements were carried out using a rotary viscometer with concentric cylinder at different temperatures (20-70 ºC) and shear rates (24- 1234 s-1). The flow parameters and energy of activation have been calculated from the flow curves and Arrhenius plots, respectively. It was found that studied polymer solutions exhibited non-Newtonian behavior, moreover, the flow properties were dependent on the blend composition. The result show that practically there was no thixotropy in studied system but some interactions between PVA and pectin in water occurred.
Comparative study on the effects of galbanic acid, galbanic ferric salt and tetrabromo galbanic acid on photo-oxidative degradation of linear low density (LLDPE) films
Authors: Shahmir Marjan , Asempour Homa 
Published: August 2014

AbstractGalbanic acid (GA) is known as an effective photo-sensitizing agent in polyethylene. This paper reports the comparative studies on photo-oxidative degradation of LLDPE films in the presence of varying amounts of galbanic ferric salt (Fe-GA), tetrabromo galbanic acid (Br-GA), GA at the optimum concentration of 0.2% (w/w) and the pure polymer film, exposed to Ultra-Vitalux sun lamp. The degradation rate was monitored through the changes in mechanical properties (retained elongation at break and retained tensile strength) and also carbonyl index. The results obtained revealed that Fe-GA efficiency in enhancing oxidation rate of polymer upon UV exposure is remarkably much more than of GA. In contrast, Br-GA is responsible for initiating photo-oxidation of the polymer and has negligible effects on the rate of degradation. Based on the results obtained, it was proposed that the photo-activity of GA in the polymer arises from the C=C bond present in the side group attached to aromatic lacton rings of additive molecule, probably through its reaction with singlet oxygen and subsequent generation of hydroperoxide. This mechanism in combination with catalytic effect of iron (III) accounted for the higher effect of Fe-GA in accelerating photo-oxidation rate of the polymer
Poly(imide-amides) oligomers based on germarylene units containing amino acid moieties: synthesis, characterization and thermal analysis
Authors: Tagle Luis H. , Terraza Claudio A. , Yazigi Nicolás , López Luciano , Ortiz Pablo A. , Leiva Angel 
Published: August 2014

AbstractFour oligomeric poly(imido-amides) (PIAs) were obtained from dicarboxylic acids, derived from two dianhydrides containing a Ge atom and the amino acids glycine or L-alanine, which reacted with the diamine bis(4- aminophenyl)-diphenylgermane, in order to obtain the PIAs containing two Ge atoms in the main chain. PIAs which contain Me/Me or Ph/Ph on the Ge atom of the dicarboxylic acids moiety, were characterized by IR and 1H and 13C NMR, and elemental analysis. The yields were over 60% with the exception of PIA-II, and the low inh values are indicative of low molecular weight species. Tg and the thermal stability were evaluated by DSC and thermogravimetry respectively. When Lalanine was included in the dicarboxylic acid, it was possible to see lower values of Tg with respect to those with glycine, due to the higher flexibility of the methyl side groups. When phenyl groups are bonded to the Ge atom of the dicarboxylic acid, also there is a decrease of the Tg in front of those with methyl groups, due to that the increase of the volume of the side groups affects negatively the free rotation of the polymeric chain. The TDT values were obtained by dynamic thermogravimetry, and show that these PIAs are not thermally stables materials, because the 10% of weight loss is lower than 400 ºC, with the exception of PIA-IV, in which the value is 403 ºC. The low thermal stability can be due to that the dicarboxylic acids are of aliphatic nature. On the other hand, there was not a clear tendency about the influence of the nature of the amino acid and the groups, methyl or phenyl, bonded to the Ge atom in the dicarboxylic acids.
Physical and mechanical properties of rigid polyurethane foams modified with polystyrene beads
Authors: Malewska Elżbieta , Sabanowska Anna , Polaczek Jerzy , Prociak Aleksander 
Published: August 2014

AbstractThis study presents a method of obtaining porous materials based on the rigid polyurethane foam (RPURF) as the matrix and containing thermoplastic polystyrene beads (EPS) as the fillers. In RPURF-EPS composites, the compact EPS were expanded after heating above a glass transition temperature of the EPS and gas vapouring incorporated inside the EPS, by using heat of exothermic reaction of polyol with isocyanate. The thermal conductivity, compressive strength, core density and cell structure of the new materials were investigated
Powder X-ray diffraction and thermal decomposition correlation studies of nano-crystalline styrene-maleic anhydride graft copolymer-ZnO composites
Authors: Kaur Inderjeet , Singh Bikram , Bhatt Parveen , Bhatt Sarvjeet S. 
Published: August 2014

AbstractNano-crystalline (nc) polymer-ZnO composite material has been successfully synthesized by treating styrene-maleic anhydride (SMA) and its graft copolymers with acrylic acid, (AAc), and acrylamide, (AAm), synthesized by chemical method with different wt% ratios of nZnO (40 nm), prepared indigenously in our laboratory, to yield polymer-ZnO nano-composite material. Characterization of SMA, grafted SMA, nc-SMA-ZnO, nc-grafted SMA-ZnO composites was carried out by X-ray diffraction and thermo-gravimetric analysis. Both the studies show an interesting correlation between X-ray and thermal data. XRD pattern of SMA copolymer shows it to be amorphous, while SMA-g-poly(AAc) and SMA-gpoly( AAm) graft copolymers show crystalline orthorhombic structure having (102) orientation with particle size of nano dimensions (44 and 40 nm respectively). Addition of nZnO to nc-SMA-g-poly(AAc) and nc-SMA-g-poly(AAm) shows appreciation in the crystalline behavior with increased intensity of the peaks in the XRD patterns. Thermo-gravimetric analysis (TGA) of SMA shows single stage decomposition with regular loss of weight while nc-SMA-g-poly(AAc) and nc-SMAg- poly(AAm) graft copolymers respectively show an abrupt weight loss up to 25% and 45% at 121.370C and thereafter proceeds with regular decomposition. However, the corresponding composite of SMA with nZnO (10 wt%) shows an abrupt weight loss of 50% similar to grafted SMA while the ZnO embedded composites of AAc and AAm grafted SMA lose 95% of the weight abruptly at the same temperature i.e.121.37 °C. The increased abrupt loss in nZnO- SMA and nZnO-nc-SMA grafted composite is correlated to the increased crystallinity upon addition of nZnO particles to the polymer system. Because of the spontaneous thermal decomposition and release of large amount of heat energy, the newly synthesized nano-composite polymer material can find use as high energy material
Synthesis and solution properties of a meta-linked anionic poly(phenylene ethynylene) conjugated polyelectrolyte
Authors: Liu Kuan , Li Yang , Yang Mujie 
Published: August 2014

AbstractA meta-linked anionic conjugated polyelectrolyte m-PPYPE-SO3Na was synthesized and characterized by UV-vis, FT-IR, and photoluminescence spectroscopy. It is brown solid readily soluble in water and methanol. The UV-vis absorption spectra of the polymer show strong absorption bands, which correspond to the π-π* transition of π-conjugated segments. Fluorescence spectra in different solvents show that this kind of polymer has solvent-dependency. It was found that the existence of polymer-type surfactant significantly increased the intensity of fluorescence of the polymer. The fluorescence of the polymer in water solution could be effectively quenched by methyl viologen. Linear fit of the quenching plots affords Stern-Volmer constants (Ksv) of 5.65×105M-1 for intrinsic fluorescence emission of the polymer m-PPYPE-SO3Na and this revealed its good fluorescence sensitivity.
Polymers containing phtalimidoalkyl groups in the side chains. effect of the alkyl groups in monolayers at the airwater interface
Authors: Gargallo Ligia , Leiva Angel , González Alvaro , Alegría Luz , Sandoval Claudia , Radic Deodato 
Published: August 2014

AbstractSurface activity of poly(methacrylate)s containing phthalimidoalkyl groups was studied. Surface pressure-area isotherms ( -A) at the air-water interface were determined. These polymers form stable and condensed monolayers. The monolayers are more condensed and the limiting surface area A0 values decrease when the number of the methylene groups in the lateral chains increases. Surface pressure variation at the semidilute region of the monolayers was expressed in terms of the scaling laws as power function of the surface concentration. The static elasticity εo and the exponent of the excluded volume υ were determined. The hydrophobicity degree of polymers was estimated from the determination of the total surface free energy values by wettability measurements. Molecular dynamic simulation (MDS) was performed in order to explain the experimental behavior of polymers at the air-water interface.
Significantly enhanced dielectric response in composite of P(VDF-TrFE) and modified multi-walled carbon-nanotubes
Authors: Wang Jingwen , Wei Nan , Wang Fang , Wu Congcong , Li Shuqin 
Published: August 2014

AbstractTo develop a high dielectric constant composite of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and multi-walled carbon-nanotubes (MWCNTs) with desirable homogeneity, MWCNTs were treated with a nitro-sulfuric acid by ultrasonication. Improvement of the dispersibility of chemically modified MWCNTs (a-MWCNTs) in polymer matrix, in comparison with that of unmodified MWCNTs in P(VDF-TrFE), was confirmed by field emission scanning electron microscopy (FESEM)-observed morphologies. Electric behavior of the composites with different volume fraction of dispersed carbon nanotubes phase can be described mainly by percolation theory. The percolation threshold (fc) of composites with a-MWCNTs (fc=0.0308) is larger than that of composites with MWCNTs (fc=0.0216) due to better dispersion of a-MWCNTs in polymer matrix and the reduction of aspect ratio of a-MWCNTs occurred in the modification procedure. The composite with 2.98 vol% (a volume fraction close to the percolation threshold) of a-MWCNTs has a dielectric constant of 592 at 100Hz and room temperature. The composite remains very flexible with an elastic modulus close to that of the parent copolymer.
Aqueous AGET ATRP of sodium 2-acrylamido-2-methyl-N-propane sulfonate yielding strong anionic comb polyelectrolytes
Authors: Tolstov Alexander , Gromadzki Daniel , Netopilík Miloš , Makuška Ričardas 
Published: August 2014

AbstractAnionic comb polyelectrolytes containing 2-acrylamido-2-methyl-Npropane sulfonate groups both in the mainchain and in the grafts were prepared by activators generated by electron transfer atom transfer radical polymerization (AGET ATRP). The synthetic route included AGET ATRP copolymerization of 2- acrylamido-2-methyl-N-propanesulfonic acid (AMPS) and 2-hydroxyethyl acrylate (HEA) followed by modification of HEA units in the copolymers by 2- bromoisobutyryl bromide yielding macroinitiators which served for “grafting from” AGET ATRP of AMPS. Composition of the final and intermediate products was determined by 1H-NMR spectroscopy, and molecular weight and polydispersity of the resulting polyelectrolytes were estimated by size exclusion chromatography (SEC). Anionic comb polyelectrolytes with relatively low density of the grafts (5 - 7 grafting sites per 100 monomeric units of the mainchain) and relatively short side chains (9 or 25 AMPS units) were synthesized and characterized.
The synthesis and characterization of the polyurethanes with antimicrobial properties
Authors: Borcan Florin , Bolcu Constantin , Filimon Nicoleta , Bandur Geza 
Published: August 2014

AbstractIn this experimental research, thin polyurethane films containing reactive functional groups (hydroxyl and amino groups) were synthesized. The raw materials used in the synthesis are: a hydroxyl component (Elastoflex W5516/115) and an isocyanate component (semiprepolimer type) based on 4,4'- diphenylmethane-diisocyanate (MDI) or toluene-2,4-diisocyanate (TDI). Two different antibiotics were adsorbed on these films: amikacin and ceftazidime which formed physical bonds with the polyurethane matrix. The films were characterized by SEM, DMA and a culture of Escherichia coli and a counting room was used in order to determine the antimicrobial efficiency.
Tobacco use among adolescents in Riyadh Saudi Arabia
Authors: Al-Makadma AbdulKarim S. , Moynihan Melissa , Dobson Sarah , Saewyc Elizabeth 
Published: August 2014

Abstract
Background: Initiation of smoking behavior during adolescence is associated with negative health outcomes. Understanding initiation of smoking behavior in adolescents in relation to other behavioral, health, and environmental factors is essential for effective behavioral modification.
Objective: The aim of this study was to describe tobacco use behaviors among adolescents in Riyadh, Saudi Arabia, and related demographic and social factors.
Subjects: A total of 1430 students aged 14–19 from high schools across the city of Riyadh participated in the study.
Methods: A comprehensive adolescent health survey was administered to students in high school classrooms across Riyadh. Data were analyzed primarily via contingency tables with χ2-tests.
Results: One in five students reported having ever smoked cigarettes, with a significantly higher proportion of boys than girls reporting tobacco use. Students who smoked had significantly lower school connectedness compared with those who never smoked. Tobacco use by family members was common, and students with at least one family member who smoked were significantly more likely to use tobacco themselves.
Conclusion: Improving school connectedness among students by fostering supportive and safe school environments could be a potential strategy for reducing adolescent smoking. Reducing smoking in the general population and educating families about being better role models for youth are also critical.
Growth impairment and growth hormone-IGF-1 axis in infantile anorexia nervosa
Authors: Ghione Silvia , Maestro Sandra , Dati Eleonora , Silvestri Virginia , Baroncelli Giampiero I. , Bertelloni Silvano 
Published: August 2014

AbstractInfantile anorexia nervosa (AN) is a specific eating disorder of prepubertal children. Poor data are available on growth hormone (GH)-insulin-like growth factor 1 (IGF-1) axis in this disorder.We report on a boy (4.5 years) with progressive growth impairment. At psychiatric assessment (DC: 0-3 R, AXIS I), he fulfilled all required criteria for diagnosis of infantile AN. Endocrine evaluation suggested impaired peripheral response to GH (high GH and low IGF-1 levels), likely related to energy deficiency.Auxological evaluation was shown as raw data and SDS using Italian reference values. GH secretion was assessed by arginine provocative test; IGFI generation test was done administering recombinant GH (0.05 mg/kg/day for four days). Psychiatric assessment was performed according to the DC:0-3R protocol.Impaired GH-IGF-1 axis may be involved in growth delay of children with infantile AN. A strict collaboration between endocrine pediatricians and child psychiatrists is advisable in the assessment of poor growing children without recognizable organic causes, showing normal/high GH levels and low IGF-1 values.
Texttheorie und textlinguistische Annotation von Korpora: Bemerkungen zur Rhetorical Structure Theory
Authors: Fritz Gerd 
Published: August 2014

Abstract
The present article contributes to the discussion of methods of corpus studies in the field of text and discourse analysis. Starting with a brief overview of bottom-up and top-down methods of corpus analysis, the article focuses on a critical examination of Rhetorical Structure Theory (RST), a framework for describing natural text that has been widely used for the annotation of texts, especially in the field of computational linguistics. This critical assessment, which is based on an action-theoretic theory of text organization, is, at the same time, used as a means of discussing some quality criteria for textual analysis. After a brief introduction to basic tenets of RST, the article discusses various features of this framework that appear problematic from a theoretical point of view and that tend to cause difficulties for practical analysis. The problems connected to these features include problems of granularity associated with the “classic” set of “rhetorical relations” as well as problems connected to the adjacency and nuclearity conditions. Furthermore it is shown that RST lacks adequate instruments for the description of the topic structure of texts and aspects of linearity and the dynamics of texts, e.g. the discontinuity of functional and thematic elements. The final section of the paper summarizes the results of this critical analysis, briefly reflecting on conceptions of multi-level annotation and suggesting some further steps in the corpus-based analysis of textual organization.
PI3P phosphatase activity is required for autophagosome maturation and autolysosome formation
Authors: Wu Yanwei , Cheng Shiya , Zhao Hongyu , Zou Wei , Yoshina Sawako , Mitani Shohei , Zhang Hong , Wang Xiaochen 
Published: August 2014

AbstractAutophagosome formation is promoted by the PI3 kinase complex and negatively regulated by myotubularin phosphatases, indicating that regulation of local phosphatidylinositol 3‐phosphate (PtdIns3P) levels is important for this early phase of autophagy. Here, we show that the Caenorhabditis elegans myotubularin phosphatase MTM‐3 catalyzes PtdIns3P turnover late in autophagy. MTM‐3 acts downstream of the ATG‐2/EPG‐6 complex and upstream of EPG‐5 to promote autophagosome maturation into autolysosomes. MTM‐3 is recruited to autophagosomes by PtdIns3P, and loss of MTM‐3 causes increased autophagic association of ATG‐18 in a PtdIns3P‐dependent manner. Our data reveal critical roles of PtdIns3P turnover in autophagosome maturation and/or autolysosome formation.
A Review and Framework for Categorizing Current Research and Development in Health Related Geographical Information Systems (GIS) Studies
Authors: Nøhr C. , Sørensen E. M. , Gudes O. , Geraghty E. M. , Shaw N. T. , Bivona-Tellez C. , Lyseen A. K. ,   the IMIA Health GIS Working Group
Published: August 2014

Summary
Objectives: The application of GIS in health science has increased over the last decade and new innovative application areas have emerged. This study reviews the literature and builds a framework to provide a conceptual overview of the domain, and to promote strategic planning for further research of GIS in health.
Method: The framework is based on literature from the library databases Scopus and Web of Science. The articles were identified based on keywords and initially selected for further study based on titles and abstracts. A grounded theory-inspired method was applied to categorize the selected articles in main focus areas. Subsequent frequency analysis was performed on the identified articles in areas of infectious and non-infectious diseases and continent of origin.
Results: A total of 865 articles were included. Four conceptual domains within GIS in health sciences comprise the framework: spatial analysis of disease, spatial analysis of health service planning, public health, health technologies and tools. Frequency analysis by disease status and location show that malaria and schistosomiasis are the most commonly analyzed infectious diseases where cancer and asthma are the most frequently analyzed non-infectious diseases. Across categories, articles from North America predominate, and in the category of spatial analysis of diseases an equal number of studies concern Asia.
Conclusion: Spatial analysis of diseases and health service planning are well-established research areas. The development of future technologies and new application areas for GIS and data-gathering technologies such as GPS, smartphones, remote sensing etc. will be nudging the research in GIS and health.
Big Data, Smart Homes and Ambient Assisted Living
Authors: Wass S. , Vimarlund V. 
Published: August 2014

Summary
Objectives: To discuss how current research in the area of smart homes and ambient assisted living will be influenced by the use of big data.
Methods: A scoping review of literature published in scientific journals and conference proceedings was performed, focusing on smart homes, ambient assisted living and big data over the years 2011-2014.
Results: The health and social care market has lagged behind other markets when it comes to the introduction of innovative IT solutions and the market faces a number of challenges as the use of big data will increase. First, there is a need for a sustainable and trustful information chain where the needed information can be transferred from all producers to all consumers in a structured way. Second, there is a need for big data strategies and policies to manage the new situation where information is handled and transferred independently of the place of the expertise. Finally, there is a possibility to develop new and innovative business models for a market that supports cloud computing, social media, crowdsourcing etc.
Conclusions: The interdisciplinary area of big data, smart homes and ambient assisted living is no longer only of interest for IT developers, it is also of interest for decision makers as customers make more informed choices among today’s services. In the future it will be of importance to make information usable for managers and improve decision making, tailor smart home services based on big data, develop new business models, increase competition and identify policies to ensure privacy, security and liability.