bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic structure and phenotypic variation in wild populations of the medicinal tetraploid species Bromelia antiacantha (Bromeliaceae)
Authors: Zanella Camila Martini , Bruxel Manuela , Paggi Gecele Matos , Goetze Márcia , Buttow Miriam Valli , Cidade Fernanda Witt , Bered Fernanda 
Published: August 2011

• Premise of the study: The patterns of genetic structure in plant populations are mainly related to the species life history and breeding system, and knowledge of these patterns is necessary for the management, use, and conservation of biological diversity. Polyploidy is considered an important mode of evolution in plants, but few studies have evaluated genetic structure of polyploid populations. We studied the patterns of genetic structure and morphological variation of Bromelia antiacantha (Bromeliaceae) populations, a polyploid terrestrial species.• Methods: Microsatellite markers and morphological analyses were used to explore patterns of genetic and morphological diversity in wild populations of B. antiacantha.• Key results: The results of our simple‐sequence repeat analyses supported that B. antiacantha is a polyploid species. The inbreeding coefficients were high and significant in all populations (FIS = 0.431), indicating homozygote excess. Bromelia antiacantha showed high levels of genetic differentiation among populations (FST = 0.224) and therefore was highly structured. High morphological variation was observed in fruit phenotypic traits in the populations studied.• Conclusions: The levels of genetic diversity and the pattern of the population's structure may be related to the low recruitment of seeds, clonal reproduction, and the population's colonization history. The genetic and morphological variability displayed in this study are important issues in planning the conservation and exploitation of this resource in a sustainable way.
De la visite médiatisée. Étude clinique
Authors: Boudarse Khalid , Dodelin Martine 
Published: August 2011

La visite médiatisée fait partie des outils utilisés par les professionnels du champ médico-social afin de permettre des contacts entre parent(s) et enfant(s). Contrairement à l’entretien et à l’observation, elle n’a pas de cadre de référence théorique et clinique précis. Comment donc concevoir un protocole et un cadre à la visite médiatisée ? Sur quelle conception de la relation d’aide pouvons-nous nous appuyer pour penser nos manières d’être et de travailler, pour penser les différents niveaux d’interactions qu’engagent les bénéficiaires des visites et pour saisir les transactions affectives et imaginaires que ces derniers nouent avec les professionnels que nous sommes ? C’est ce cadre spécifique de la VM que l’article interroge en s’appuyant sur l’exemple d’un dispositif mis en place pour restaurer le contact entre un père souffrant de psychose et sa petite fille, victime de violences paternelles quand elle était nourrisson.
The Smallest Pisot Element in the Field of Formal Power Series Over a Finite Field
Authors: Chandoul A. , Jellali M. , Mkaouar M. 
Published: August 2011

Abstract.Dufresnoy and Pisot characterized the smallest Pisot number of degree n ≥ 3 by giving explicitly its minimal polynomial. In this paper, we translate Dufresnoy and Pisot’s result to the Laurent series case. The aim of this paper is to prove that the minimal polynomial of the smallest Pisot element (SPE) of degree n in the field of formal power series over a finite field is given by P(Y) = Yn–XYn-1–αn where α is the least element of the finite field 픽q\{0} (as a finite total ordered set). We prove that the sequence of SPEs of degree n is decreasing and converges to αX: Finally, we show how to obtain explicit continued fraction expansion of the smallest Pisot element over a finite field.
Hair lead levels to evaluate the subclinical impact of lead on growth in Sardinian children (Italy)
Authors: Sanna Emanuele , Vallascas Elisabetta 
Published: August 2011

AbstractObjectives:The aim of this study was to determine if there are significant relationships between lead concentrations in children's hair and height, sitting height, and estimated leg length.Methods:We analyzed three samples collected at different times: 1998, 2002, 2007. The total sample consisted of 825 children between 11 and 14 years of age living in different municipalities of Sardinia (Italy). Inductively coupled plasma atomic emission spectrometry (1998), inductively coupled plasma atomic absorption spectrometry (2002), and inductively coupled mass spectrometry (2007) were used to measure the lead concentration in hair (PbH). Some AAS measurements were also performed on the 1998 and 2007 samples to check the reliability of the data.Results:The mean PbH is much higher in 1998 (5.84 μg/g) than in 2002 (1.49 μg/g) and 2007 (0.78 μg/g). Multivariate regression analysis of the three samples, controlling for age and sex, indicates a subclinical impact of lead on growth that differs according to the mean lead concentration in the hair. In fact, for 1998, the relationships between all three anthropometric variables and logPbH are significantly negative. For 2002, there are significant negative associations between height and estimated leg length and logPbH but not between sitting height and logPbH. For 2007, there are not significant associations between logPbH and anthropometric variables.Conclusions:Our results support the use of hair lead levels as a biomarker to assess the impact of subclinical lead on the physical growth of children, especially when the study area presents medium and/or high levels of lead pollution. Am. J. Hum. Biol., 2011. © 2011 Wiley‐Liss, Inc.
SLC9A9 mutations, gene expression, and protein–protein interactions in rat models of attention‐deficit/hyperactivity disorder
Authors: Zhang‐James Yanli , DasBanerjee Tania , Sagvolden Terje , Middleton Frank A. , Faraone Stephen V. 
Published: August 2011

AbstractSLC9A9 (solute carrier family 9, member 9, also known as Na+/H+ exchanger member (NHE9)) is a membrane protein that regulates the luminal pH of the recycling endosome, an essential organelle for synaptic transmission and plasticity. SLC9A9 has been implicated in human attention deficit hyperactivity disorder (ADHD) and in rat studies of hyperactivity. We examined the SLC9A9 gene sequence and expression profile in prefrontal cortex, dorsal striatum and hippocampus in two genetic rat models of ADHD. We report two mutations in a rat model of inattentive ADHD, the WKY/NCrl rat, which affect the interaction of SLC9A9 with calcineurin homologous protein (CHP). We observed an age‐dependent abnormal expression of SLC9A9 in brains of this inattentive model and in the Spontaneous Hypertensive Rat (SHR) model of ADHD. Our data suggest a novel mechanism whereby SLC9A9 sequence variants and abnormalities in gene expression could contribute to the ADHD‐like symptoms of rat models and possibly the pathophysiology of ADHD in humans. © 2011 Wiley‐Liss, Inc.
Electrocorticographic control of a prosthetic arm in paralyzed patients
Authors: Yanagisawa Takufumi , Hirata Masayuki , Saitoh Youichi , Kishima Haruhiko , Matsushita Kojiro , Goto Tetsu , Fukuma Ryohei , Yokoi Hiroshi , Kamitani Yukiyasu , Yoshimine Toshiki 
Published: August 2011

AbstractObjective:Paralyzed patients may benefit from restoration of movement afforded by prosthetics controlled by electrocorticography (ECoG). Although ECoG shows promising results in human volunteers, it is unclear whether ECoG signals recorded from chronically paralyzed patients provide sufficient motor information, and if they do, whether they can be applied to control a prosthetic.Methods:We recorded ECoG signals from sensorimotor cortices of 12 patients while they executed or attempted to execute 3 to 5 simple hand and elbow movements. Sensorimotor function was severely impaired in 3 patients due to peripheral nervous system lesion or amputation, moderately impaired due to central nervous system lesions sparing the cortex in 4 patients, and normal in 5 patients. Time frequency and decoding analyses were performed with the patients' ECoG signals.Results:In all patients, the high gamma power (80–150Hz) of the ECoG signals during movements was clearly responsive to movement types and provided the best information for classifying different movement types. The classification performance was significantly better than chance in all patients, although differences between ECoG power modulations during different movement types were significantly less in patients with severely impaired motor function. In the impaired patients, cortical representations tended to overlap each other. Finally, using the classification method in real time, a moderately impaired patient and 3 nonparalyzed patients successfully controlled a prosthetic arm.Interpretation:ECoG signals appear useful for prosthetic arm control and may provide clinically feasible motor restoration for patients with paralysis but no injury of the sensorimotor cortex. ANN NEUROL 2012;
Zwitterionic ring opening polymerization of lactide by metal free catalysts: Production of cyclic polymers
Authors: Prasad Aitha Vishwa , Stubbs Ludger Paul , Ma Zhun , Yinghuai Zhu 
Published: August 2011

AbstractTailor made N‐heterocyclic carbene (NHC) catalyst precursors namely (+) and (−) 1‐methyl‐3‐menthoxymethyl imidazolium chloride have been synthesized in high yield with a literature modified procedure. A reaction of catalyst precursor with potassium tert butoxide in situ generates the NHC catalyst. The zwitterionic ring opening polymerization of lactide (LA) mediated by a catalytic system composed of NHC catalyst at 25°C under argon atmosphere led to a cyclic poly(lactide) of a high molecular weight with a narrow molecular weight distribution. The cyclic poly(lactide) was characterized by NMR spectroscopy, Gel Permeation Chromatography (GPC) and Matrix‐assisted laser desorption ionization‐time of flight mass spectrometry (MALDI‐TOF MS). The NHC catalysts are active for lactide polymerization in the presence of air and elevated temperatures at 55°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Dielectric relaxation and Schottky conduction of IR laser irradiated Makrofol‐DE polycarbonate
Authors: Hanafy Taha A. 
Published: August 2011

AbstractThe effect of IR laser pulses on the dielectric properties, X‐ray diffraction, Fourier transform infrared spectroscopy (FTIR), and I–V characteristics of Makrofol‐DE 1‐1 CC polycarbonate has been investigated in the temperature and frequency ranges of 300–375K and 10 kHz–4 MHz, respectively. IR laser fluencies are set from 0.47 to 7.07 J/cm2. Three relaxation processes namely, α, β, and γ have been obtained. The first process is due to the micro Brownian motion of the segmental parts of the main chain. The second process was assigned to the local motion of the dipoles within the crystalline phases of the sample. The third one was attributed to the crank shaft motion along the main chains of the Makrofol. X‐ray diffraction and FTIR spectroscopy have revealed that the irradiation of Makrofol at the fluence range 0.94–7.07 J/cm2 causes crosslinking formation inside the sample. Reduction in crystallinity of Makrofol at higher IR laser doses is due to the crosslinking formation taking place within polymer matrix. At higher voltage, the conduction mechanism of Makrofol‐DE was identified as Shottky type. The attained results suggested strongly the applicability of Makrofol‐DE in IR laser pulses dosimetry. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Quantitative determination of degree of conversion in photocured poly(urethane‐dimethacrylate)s by Fourier transform infrared spectroscopy
Authors: Barszczewska‐Rybarek Izabela M. 
Published: August 2011

AbstractIn this work, infrared spectroscopy was used to characterize the degree of double bonds conversion (DC) in six series of poly(urethane‐dimethacrylate)s, derived from dicarbamates of oligoethylene glycols monomethacrylates and aliphatic, cycloaliphatic and aromatic diisocyanates. To evaluate the degree of conversion in polymers devoid of aromatic moieties, two methods of calculation have been proposed: internal band ratio method, with carbonyl stretching vibrations as a standard, and a method involving the direct observation of the decrease in the intensity of CC stretching band. The validity of these methods has been checked on polymers with aromatic structures, by comparing the results with those obtained by the internal band ratio method applying an aromatic band as a reference. A good correlation between the degree of conversion from two internal standard methods, using aromatic band and carbonyl band as references, was obtained. It was shown that the degree of conversion increases as the number of oxyethylene units increases. Polymerization of monomers with aliphatic cores resulted in higher DC values, while those with cycloaliphatic and aromatic cores—resulted in lower DC values. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Nanosilica filled poly(glycerol‐sebacate‐citrate) elastomers with improved mechanical properties, adjustable degradability, and better biocompatibility
Authors: Wu Yan , Shi Rui , Chen Dafu , Zhang Liqun , Tian Wei 
Published: August 2011

AbstractModified nano‐fumed silica (mn‐silica)/poly(glycerol‐sebacate‐citrate), in which mn‐silica loadings varied from 0 to 20 phr, were prepared by in situ polymerization and surface modification. The influence of mn‐silica loadings on the structure and properties of the composites was studied. Scanning electron microscope (SEM) and transmission electron microscope (TEM) photos showed that the mn‐silica dispersed well as nano‐scale network in the matrix, and exhibited good interfacial bonding with the matrix. The mn‐silica filled composites exhibited excellent comprehensive properties relative to the unfilled elastomers. Specially, the tensile strength improved from 0.9 MPa to 5.3 MPa. Results of the in vitro degradation test suggested that mn‐silica loading could adjust the degradation rate of the composites in simulated body fluid solution. The MTT colorimetry with L929 cells substantiated that the introduction of mn‐silica weakened the cytotoxicity of elastomers and made the composites accepted as qualified biomedical materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Simulation of crystallization kinetics and morphology during nonisothermal crystallization in short fiber reinforced composites
Authors: Ruan Chunlei , Ouyang Jie 
Published: August 2011

AbstractComputer simulation for the nonisothermal crystallization of short fiber reinforced composites is presented. The pixel coloring technique is implemented to the study of crystal morphology evolution as well as the crystallization kinetics. A parametric study is used to explore the influences of thermal conditions and fibers on the crystallization in the reinforced system. We particularly focus on the roles of cooling rate, initial temperature, nucleation density on fibers, fiber content, fiber length, and fiber diameter. The results indicate that cooling rate is a significant factor to the crystallization kinetics as well as the morphology. The initial temperature only affects the crystallization kinetics and has minor impact on the morphology. The additional fibers have a dual effect on the crystallization. They depress the crystallization rate by hindering the spherulitic growth and accelerate the crystallization rate by providing nucleation sites. The constraining effect is mainly dependent on fiber content, whereas the enhancing effect is mainly determined by fiber surface and fiber nucleation density as well as surface nucleation mode. Present results are hoping to give more insight about the crystallization in short fiber reinforced composites and be more helpful to the industrial application. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of dendritic polyaniline nanofibers by using soft template of sodium alginate
Authors: Bhowmick Biplab , Bain Mrinal Kanti , Maity Dipanwita , Bera Nirmal Kumar , Mondal Dibyendu , Mollick Md. Masud Rahaman , Maiti Prabir Kumar , Chattopadhyay Dipankar 
Published: August 2011

AbstractHighly crystallized polyaniline (PANI) nanofibers were synthesized by oxidative polymerization of aniline in the presence of sodium alginate as a soft template in HCl and ammonium peroxydisulfate (APS) acting as an oxidizing agent. Sodium alginate, in presence of a protonic acid like HCl, formed hydrogen bonds with anilium ions or oligomers. The formed hydrogen bonds provide the driving force to form PANI nanofibers. The nanofibers were separated from the alginate gel by degelling with ammonium hydroxide and during degelling emeraldine salt was converted into emeraldine base form. The polymerized PANI was characterized using ultraviolet (UV)–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and scanning electron microscopy (SEM). UV and FTIR spectra showed that the presence of sodium alginate had no effect on the electronic state and backbone structures of the resulting PANI products. It was evident from the XRD analysis that the obtained PANI nanofibers exhibit higher crystalline order. SEM micrographs showed that PANI nanofibers were just like a mat of interwoven twisted nanofibers. After magnification of the SEM image, it was found that most of the nanofibers were interconnected to form ramose structures rather than isolated nanofibers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of NBR on epoxy/glass prepregs properties
Authors: Galledari Nasim Abuali , Beheshty Mohammad Hosain , Barmar Mohammad 
Published: August 2011

AbstractSolid acrylonitrile‐butadiene rubber (NBR) was used in epoxy resin for toughening and also for increasing the tack of epoxy/glass prepregs. The NBR used in this study was a rubber with 33% acrylonitrile content. The changes in thermal and mechanical properties such as glass transition temperature (Tg), curing characteristics and lap‐shear strength have been studied. For this purpose, three types of prepregs with two levels of NBR content of 3 and 5%, were prepared. Prepregs were made by solvent type impregnation apparatus. In this method, resin impregnates satin textile glass fiber under the controlled and constant condition of line speed and oven temperature. Prepregs were B‐staged for about 3%. The cure characterization, Tg and flow behavior were evaluated using differential scanning calorimetry and rheological analysis. Results showed that increasing the rubber content caused the following effects: (a) delay in gel time of prepregs, (b) increase in activation energy of prepregs, and (c) decrease in total heat of curing reaction. It is interesting that NBR increased the tack of epoxy/glass prepreg but, had no effect on its resin flow behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Melt processability of polytetrafluoroethylene: Effect of melt treatment on tensile deformation mechanism
Authors: Li Min , Zhang Wei , Wang Chaosheng , Wang Huaping 
Published: August 2011

AbstractIt is widely accepted that the melt processibility of polytetrafluoroethylene (PTFE) is poor. In this article, a high‐molecular‐weight PTFE was extruded smoothly with a modified die; and critical shear rate could be raised to 4 s−1, using a die with L/D (length to diameter) ratio of 200. Meanwhile, we compared the current PTFE fiber spinning method with melt spinning to investigate the effects of high‐temperature treatment on the drawability of PTFE and found that the processing sequence could play a key role. The deformation imposed before or after the high‐temperature treatment could determine whether the fibrillation can be achieved continuously and effectively. Based on the experiment phenomenon, together with the results of differential scanning calorimetry, X‐ray diffraction, and scanning electron microscopy characterization, we proposed a model to describe the submicron structural change of PTFE during extension. From this model, the fundamental mechanism for the poor melt processibility of PTFE was elucidated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Compression wood as a source of reinforcing filler for thermoplastic composites
Authors: Buyuksari Umit , Ayrilmis Nadir , Akbulut Turgay 
Published: August 2011

AbstractCompression wood (CW) is a reaction wood formed in gymnosperms in response to various growth stresses. Many of the anatomical, chemical, physical, and mechanical properties of CW differ distinctly from those of normal wood. Because of different properties, the CW is much less desirable than normal wood. This study was conducted to investigate the suitability of CW flour obtained from black pine (Pinus nigra Arnold) in the manufacture of wood plastic composite (WPC). Polypropylene (PP) and CW flour were compounded into pellets by twin‐screw extrusion, and the test specimens were prepared by injection molding. WPCs were manufactured using various weight percentages of CW flour/PP and maleic anhydride‐grafted PP (MAPP). Water absorption (WA), modulus of rupture (MOR), and modulus of elasticity (MOE) values were measured. The results showed that increasing of the CW percentage in the WPC increased WA, MOR, and MOE values. Using MAPP in the mixture improved water resistance and flexural properties. CW flour of black pine can be used for the manufacturing of WPC as a reinforcing filler. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis, characterization, and degradation investigation of water‐soluble β‐cyclodextrin‐based epoxy resins
Authors: Kang Nianjun , Du Zhongjie , Li Hangquan , Zhang Chen , Zhao Zhehan 
Published: August 2011

AbstractA series of β‐cyclodextrin‐based epoxy resins were synthesized with different epoxy equivalent weights. Their chemical structures were characterized with Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance Spectroscopy (NMR) examination. These epoxy resins were cured using L‐arginine as a curing agent, and the degradation behavior of the cured resins was evaluated under different acidic buffer solutions at 37°C. The degradable behavior of such epoxy resins suggested potential applications as environment friendly materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Temperature effect on the swelling of PAAm‐κ‐carrageenan composites
Authors: Evingür G. Akın , Pekcan Ö. 
Published: August 2011

AbstractThe steady‐state fluorescence (SSF) technique was used for studying swelling of disc‐shaped polyacrylamide (PAAm)‐κ‐carrageenan (κC) composites which were prepared by free‐radical crosslinking copolymerization at 80°C. Pyranine was introduced as a fluorescence probe during polymerization. Swelling experiments were performed in water at various temperatures by real‐time monitoring of the pyranine (Py) fluorescence intensity, I which decreased as swelling proceeded. Stern–Volmer equation is modified for low quenching efficiencies to interpret the behavior of Py intensity during the swelling of PAAm‐κC composites. The Li‐Tanaka equation was used to determine the swelling time constants, τ1, and cooperative diffusion coefficients, D0, from fluorescence intensity, weight, and volume variations of the composites at various temperatures. It was observed that τ1 first decreased up to 40°C and then increased; naturally, D0 increased up to 40°C and then decrease for all κC content gels. Swelling activation energies, ΔE, were measured for the swelling composites, which are found to be exothermic and endothermic in between 30–40 and 40–60°C, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012