bluuebunny/crossref_metadata_2025 huggingface dataset:
Limited response of peatland CH4 emissions to abrupt Atlantic Ocean circulation changes in glacial climates
Authors: Hopcroft P. O. , Valdes P. J. , Wania R. , Beerling D. J.
Published: June 2013

Abstract. Ice-core records show that abrupt Dansgaard-Oeschger climatic warming events of the last glacial period were accompanied by large increases in the atmospheric CH4 concentration (up to 200 ppbv). These abrupt changes are generally regarded as arising from the effects of changes in the Atlantic Ocean meridional overturning circulation and the resultant climatic impact on natural CH4 sources, in particular wetlands. We use two different ecosystem models of wetland CH4 emissions to simulate northern CH4 sources forced with coupled general circulation model simulations of five different time periods during the last glacial to investigate the potential influence of abrupt ocean circulation changes on atmospheric CH4 levels during D-O events. The simulated warming over Greenland of 7–9 °C in the different time-periods is at the lower end of the range of 11–15 °C derived from ice-cores, but is associated with strong impacts on the hydrological cycle, especially over the North Atlantic and Europe during winter. We find that although the sensitivity of CH4 emissions to the imposed climate varies significantly between the two ecosystem emissions models, the model simulations do not reproduce sufficient emission changes to satisfy ice-core observations of CH4 increases during abrupt events. This suggests that alternative scenarios of climatic change could be required to explain the abrupt glacial CH4 variations.
Numerical issues associated with compensating and competing processes in climate models: an example from ECHAM-HAM
Authors: Wan H. , Rasch P. J. , Zhang K. , Kazil J. , Leung L. R.
Published: June 2013

Abstract. The purpose of this paper is to draw attention to the need for appropriate numerical techniques to represent process interactions in climate models. In two versions of the ECHAM-HAM model, different time integration methods are used to solve the sulfuric acid (H2SO4) gas evolution equation, which lead to substantially different results in the H2SO4 gas concentration and the aerosol nucleation rate. Using convergence tests and sensitivity simulations performed with various time stepping schemes, it is confirmed that numerical errors in the second model version are significantly smaller than those in version one. The use of sequential operator splitting in combination with a long time step is identified as the main reason for the large systematic biases in the old model. The remaining errors of nucleation rate in version two, related to the competition between condensation and nucleation, have a clear impact on the simulated concentration of cloud condensation nuclei (CCN) in the lower troposphere. These errors can be significantly reduced by employing solvers that handle production, condensation and nucleation at the same time. Lessons learned in this work underline the need for more caution when treating multi-timescale problems involving compensating and competing processes, a common occurrence in current climate models.
Potential evaporation estimation through an unstressed surface energy balance and its sensitivity to climate change
Authors: Barella-Ortiz A. , Polcher J. , Tuzet A. , Laval K.
Published: June 2013

Abstract. Potential evaporation (ETP) is a basic input for hydrological and agronomic models, as well as a key variable in most actual evaporation estimations. It has been approached through several diffusive and energy balance methods, out of which the Penman–Monteith equation is recommended as the standard one. In order to deal with the diffusive approach, ETP must be estimated at a sub-diurnal frequency, as currently done in land surface models (LSM). This study presents an improved method, developed in the ORCHIDEE LSM, which consists in estimating ETP through an unstressed surface energy balance (USEB method). The results confirm the quality of the estimation which is currently implemented in the model (Milly, 1992). ETP has also been estimated using a reference equation (computed at a daily time step) provided by the Food and Agriculture Organization (FAO). First, a comparison for a reference period under current climate conditions, shows that both formulations differ, specially in arid areas. However, they supply similar values when FAO's assumption of neutral stability conditions is relaxed, by replacing FAO's aerodynamic resistance by the model's one. Furthermore, if the vapour pressure deficit (VPD) estimated for FAO's equation, is substituted by ORCHIDEE's VPD or its humidity gradient, the daily mean estimate is further improved. In a second step, ETP's sensitivity to climate change is assessed comparing trends in both formulations for the 21st Century. It is found that the USEB method shows a higher sensitivity. Both VPD and the model's humidity gradient, as well as the aerodynamic resistance have been identified as key parameters in governing ETP trends. Finally, the sensitivity study is extended to three empirical approximations based on temperature, net radiation and mass transfer (Hargreaves, Priestley–Taylor and Rohwer, respectively). The sensitivity of these methods is compared to the USEB method's one to test if simplified equations are able to reproduce the impact of climate change.
Joint analysis of infrasound and seismic signals by cross wavelet transform: detection of Mt. Etna explosive activity
Authors: Cannata A. , Montalto P. , Patanè D.
Published: June 2013

Abstract. The prompt detection of explosive volcanic activity is crucial since this kind of activity can release copious amounts of volcanic ash and gases into the atmosphere, causing severe dangers to aviation. In this work, we show how the joint analysis of seismic and infrasonic data by wavelet transform coherence (WTC) can be useful to detect explosive activity, significantly enhancing its recognition that is normally done by video cameras and thermal sensors. Indeed, the efficiency of these sensors can be reduced (or inhibited) in the case of poor visibility due to clouds or gas plumes. In particular, we calculated the root mean square (RMS) of seismic and infrasonic signals recorded at Mt. Etna during 2011. This interval was characterised by several episodes of lava fountains, accompanied by lava effusion, and minor strombolian activities. WTC analysis showed significantly high values of coherence between seismic and infrasonic RMS during explosive activity, with infrasonic and seismic series in phase with each other, hence proving to be sensitive to both weak and strong explosive activity. The WTC capability of automatically detecting explosive activity was compared with the potential of detection methods based on fixed thresholds of seismic and infrasonic RMS. Finally, we also calculated the cross correlation function between seismic and infrasonic signals, which showed that the wave types causing such seismo-acoustic relationship are mainly incident seismic and infrasonic waves, likely with a common source.
Integrated tsunami vulnerability and risk assessment: application to the coastal area of El Salvador
Authors: González-Riancho P. , Aguirre-Ayerbe I. , García-Aguilar O. , Medina R. , González M. , Aniel-Quiroga I. , Gutiérrez O. Q. , Álvarez-Gómez J. A. , Larreynaga J. , Gavidia F.
Published: June 2013

Abstract. Advances in the understanding and prediction of tsunami impacts allow the development of risk reduction strategies for tsunami-prone areas. This paper presents a methodological framework for the integrated tsunami vulnerability and risk assessment. It deals with the complexity and variability of coastal zones by means of (i) an integral approach to cover the entire risk related process, from the hazard, vulnerability and risk assessments to the final risk management; (ii) an integrated approach to combine and aggregate the information stemming from the different dimensions; and (iii) a dynamic and scale dependant approach to integrate the spatiotemporal variability considerations. This framework aims at establishing a clear connection to translate the vulnerability and risk assessment results into adequate target-oriented risk reduction measures, bridging the gap between science and management for the tsunami hazard. The framework is applicable to other types of hazards, having been successfully applied to climate change hazard.
Filosofía Ambiental Sudamericana
Authors: Rozzi Ricardo ,   Center for Environmental Philosophy, The University of North Texas
Published: June 2013

A comienzos del siglo XXI, América del Sur alberga la mayor biodiversidad del mundo para la mayoría de los grupos de plantas y animales, como también una variedad de movimientos en defensa del medio ambiente, que incluyen comunidades urbanas y rurales. La filosofía académica sudamericana, sin embargo, ha prestado escasa atención a este rico contexto biocultural. Para nutrir una filosofía ambiental regional emergente, identifico tres fuentes principales. Primero, una variedad de cosmovisiones y prácticas ecológicas, ancestrales y contemporáneas ofrecen un rico espectro biocultural de pensamiento ambiental de América del Sur que puede ser examinado y valorado a través del trabajo de la antropología cultural, la filosofía de la liberación, la pedagogía de la liberación, la teología de la liberación, el ecofeminismo y la conservación biocultural. En segundo lugar, en las universidades de América del Sur se han formado recientemente algunos grupos interdisciplinarios académicos en la investigación y enseñanza de la filosofía ambiental, con el apoyo del Programa de las Naciones Unidas del Medio Ambiente, o gracias a los intereses individuales de algunos investigadores. En tercer lugar, expresiones artisticas y movimientos sociales han demandado cada vez más la incorporación de valores ambientales en las políticas regionales y en los procesos de toma de decisiones. Estas tres fuentes pueden fomentar el diálogo intercultural, internacional y transdisciplinario para seguir desarrollando una filosofía ambiental sudamericana que brote desde su extraordinaria diversidad biocultural.
Le rôle des femmes dans la vie de jeunes pères vivant en contexte de vulnérabilité
Authors: Devault Annie , Denis Lorraine , Lacharité Carl , de Montigny Francine
Published: June 2013

Les hommes qui vivent en contexte d’exclusion sociale et économique et qui deviennent pères au début de l’âge adulte trouvent souvent dans cette transition la motivation pour se prendre en main malgré les obstacles inhérents à leur situation. La présente étude analyse le rôle des femmes dans l’entourage des pères, soit leur propre mère et la mère de leurs enfants. Les résultats vont dans le sens d’un renouvellement profond des rôles masculins et féminins. Ainsi, il est fréquent de constater que les mères des jeunes hommes agissent comme modèle parental et que les relations coparentales ne suivent pas un modèle traditionnel.
Protéger les enfants à l’aide des durées maximales d’hébergement : qu’en pensent les acteurs des centres jeunesse ?
Authors: Drapeau Sylvie , Saint-Jacques Marie-Christine , Poitras Karine , Turcotte Geneviève , Turcotte Daniel , Moisan Sylvie
Published: June 2013

Le présent article constitue un premier regard sur l’introduction de durées maximales d’hébergement dans la législation québécoise visant à protéger les enfants. Les résultats présentés sont, à quelques exceptions près, basés sur le point de vue des professionnels des centres jeunesse. Cent cinquante neuf personnes, provenant de trois centres jeunesse du Québec, ont été rencontrées lors d’entrevues individuelles ou de groupe. Le discours dominant chez le personnel des centres jeunesse reflète une grande adhésion au but poursuivi par l’introduction des durées maximales d’hébergement. Il est plus nuancé concernant l’impact sur les parents et l’application de cette modification dans la pratique.
Les enjeux de l’application des régimes de protection de la jeunesse aux familles autochtones
Authors: Guay Christiane , Grammond Sébastien
Published: June 2013

Le régime provincial de protection de la jeunesse tend à marginaliser les conceptions autochtones de la famille, qui sont souvent fondées sur le rôle de la famille élargie et des formes d’adoption coutumières propres à chaque communauté. En effet, les intervenants sociaux et les tribunaux prennent généralement des décisions en se fondant sur leurs propres références culturelles, ce qui les conduit à méconnaître les conceptions autochtones de la famille. Les directives données par le législateur de tenir compte de la culture autochtone ont eu peu d’effet pratique. Seule l’autonomie gouvernementale des peuples autochtones en matière de protection de la jeunesse paraît pouvoir changer la donne.
Deux mères, un donneur et des enfants. Motivations des actrices et acteurs quant à l’établissement de la famille lesboparentale avec donneur connu
Authors: Côté1 Isabel
Published: June 2013

L’une des pratiques familiales émergentes méconnue est la famille homoparentale. Bien qu’elle soit l’objet de recherche depuis plusieurs années, il reste un important travail de production de savoirs sur cette dynamique familiale. Cet article présente une partie des résultats d’une recherche portant sur un type spécifique de famille homoparentale, soit la famille lesboparentale dont les enfants sont nés d’un donneur de sperme connu. Plus précisément, dans cet article, nous analyserons les motivations des mères à avoir leurs enfants avec un donneur connu et les raisons qui ont amené les donneurs à collaborer à l’établissement du projet parental du couple lesbien.
L’art communautaire, un espace pour construire la reconnaissance sociale des femmes criminalisées au Québec ?1
Authors: Leduc2 Véronique
Published: June 2013

L’importance des stratégies communautaires dans l’intervention auprès des femmes criminalisées est reconnue par nombre d’acteurs sociaux, y compris les Services correctionnels. Des auteurs ont également démontré, d’une part, que la reconnaissance sociale est fondamentale à la justice sociale et, d’autre part, que l’art communautaire permet une prise de pouvoir favorisant la reconnaissance et la transformation sociale. L’article présente une synthèse des résultats d’une recherche auprès de participantes à un projet d’art communautaire en milieu carcéral féminin, afin de saisir en quoi ce dernier fut un espace de construction de leur reconnaissance sociale.
Les réponses sociales au travail du sexe des femmes : quelle place pour le renouvellement démocratique des interventions sociales ?
Authors: Bédard Amélie
Published: June 2013

Le but de cet essai critique est de faire la démonstration que le travail du sexe des femmes est traversé par des enjeux grandement diversifiés qui ont un impact sur les représentations sociales véhiculées à l’égard des femmes. Il adopte une perspective d’analyse constructiviste-foucaldienne afin d’illustrer l’institutionnalisation des normes sur la sexualité des femmes. Le texte démontre comment la prostitution féminine constitue une construction sociale. Puis il illustre le débat politique qui entoure la question et au sein duquel différents courants de pensées féministes et modèles de régulation ont émergé. Finalement, il aborde la prostitution des femmes en tant qu’objet d’intervention en travail social.
First Experience Using 4‐Dimensional Hysterosalpingo‐Contrast Sonography With SonoVue for Assessing Fallopian Tube Patency
Authors: He Yanni , Geng Qiang , Liu Hongmei , Han Xiaohua
Published: June 2013

This study was conducted to describe our first experience using transvaginal 4‐dimensional (4D) hysterosalpingo‐contrast sonography with SonoVue (Bracco International BV, Amsterdam, the Netherlands) for diagnosis of fallopian tube patency. The study was prospective and conducted in a university hospital setting. The sonographic procedures included 2‐dimensional transvaginal sonography for evaluating uterine and ovarian mobility, observing intubation, and determining the initial plane and 4D hysterosalpingo‐contrast sonography for observing periovarian and pelvic diffusion. Ninety‐six outpatients visiting infertility clinics underwent 4D hysterosalpingo‐contrast sonography. All patients finished the examination successfully. A total of 192 fallopian tubes were assessed, of which 95 (49.5%) were classified as type A (the tube was patent, and the contrast agent flowed smoothly through it), 72 (37.5%) as type B (the tube was patent, but the contrast agent did not flow smoothly inside it), and 25 (13.0%) as type C (blocked). Sixteen patients underwent laparoscopy or laparoscopy combined with hysteroscopy; 28 tubes (87.5%) were concordant with laparoscopy. The sensitivity, specificity, positive predictive value, negative predictive value, and Youden index for 4D hysterosalpingo‐contrast sonography versus laparoscopy were 81.8%, 90.5%, 81.8%, 90.5%, and 0.72 respectively. In total, 92.7% of patients did not require a hospital stay after 4D hysterosalpingo‐contrast sonography, and none need resuscitation. The others stayed in the hospital for clinical observation because of a severe vasovagal reaction or severe pain but received only bed rest without any medical treatment. Forty patients (41.7%) felt slight pain; 39 (40.6%) felt moderate pain; and 15 (15.6%) had a vasovagal reaction. No procedure or postprocedure complications occurred in any patient. In conclusion, 4D hysterosalpingo‐contrast sonography with SonoVue is an available screening method for assessment of tubal patency and is tolerable for most patients.
Hyperreactio Luteinalis (Enlarged Ovaries) During the Second and Third Trimesters of Pregnancy
Authors: Lynn Karen N. , Steinkeler Jill A. , Wilkins-Haug Louise E. , Benson Carol B.
Published: June 2013

The objective of this series was to assess sonographic and clinical findings in patients with hyperreactio luteinalis (HL; enlarged ovaries). We retrospectively identified 31 patients with HL and collected data including gestational age, maximum ovarian size, and pregnancy outcomes. Hyperreactio luteinalis was detected at a mean gestational age of 21.6 weeks, reaching average maximum ovarian volumes of 417 and 359 mL on the right and left, respectively. After the first trimester, HL appears to be associated with multiple gestations, twin‐twin transfusion syndrome, gestational trophoblastic disease, and Beckwith‐Wiedemann syndrome. When HL is present, maternal complications such as preeclampsia are common, and preterm delivery often results.
Premature Closure or Restriction of the Foramen Ovale
Authors: Li Yi-Dan , Li Zhi-An , He Yi-Hua
Published: June 2013

Premature closure or restriction of the foramen ovale may occur at any time during pregnancy and may be due to various causes. We describe 2 patients with premature closure or restriction of the foramen ovale during the third trimester. In both patients the foramen ovale was detected by directional enhanced flow imaging technology (DeFLOW; Hitachi‐Aloka Medical, Ltd, Tokyo, Japan), a novel method of imaging blood flow dynamics. Our findings indicate that D‐eFLOW can display blood flow information with higher sensitivity and resolution than conventional methods, helping obstetricians and pregnant women make timely decisions about delivery.
Cesarean Scar Pregnancy
Authors: Uysal Fatma , Uysal Ahmet , Adam Gürhan
Published: June 2013

Cesarean scar pregnancy is a very rare form of pregnancy and a life‐threatening situation. It has become an important and serious problem over the last 10 years, as a result of the worldwide increase in cesarean births. In this retrospective series, the diagnosis of cesarean scar pregnancy, management, treatment methods, risk factors, and possibility of subsequent normal pregnancy are discussed, and case descriptions are presented.
Controlled Planar Alignment of Discotic Liquid Crystals in Microchannels Made Using SU8 Photoresist
Authors: Cattle James , Bao Peng , Bramble Jonathan P. , Bushby Richard J. , Evans Stephen D. , Lydon John E. , Tate Daniel J.
Published: June 2013

A range of triphenylene and phthalocyanine‐based discotic liquid crystals (DLCs) can be aligned within micrometer‐scale channels formed from SU8 patterned on silicon or glass surfaces. The channels can be filled with the DLC in its isotropic phase using capillary action. Alignment occurs spontaneously as the sample is slowly cooled into the Colh phase. Whilst all of these DLCs align with the columns perpendicular to the surface when they are ‘sandwiched’ between glass slides, in these channels, the DLC aligns with the column director parallel to the surface. It is also constrained to lie across the channels. The same alignment occurs when these DLCs are confined between SU8‐topped interdigitated gold electrodes where it gives the optimum orientation for electrode‐to‐electrode conduction. The quality of the alignment depends on the particular liquid crystal used and on the width of the channel. For the Colr phase of octaoctylphthalocyanine there is additional epitaxial control over the orientation of the lattice such that the a/c face of the lattice is parallel to the surface. This is an important prerequisite for creating a bistable display device that switches by virtue of changing the direction of the tilt of the discs.
Predicting Contact Angle of Electrospun PAN Nanofiber Mat Using Artificial Neural Network and Response Surface Methodology
Authors: Moghadam Bentolhoda Hadavi , Hasanzadeh Mahdi
Published: June 2013

In this work, the simultaneous effects of four electrospinning parameters, including solution concentration (wt%), applied voltage (kV), tip to collector distance (cm), and volume flow rate (mL/h), on contact angle (CA) of polyacrylonitrile nanofiber mat are studied. To optimize and predict the CA of electrospun fiber mat, response surface methodology (RSM) and artificial neural network (ANN) are employed and a quantitative relationship between processing variables and CA of the electrospun fibers is established. It is found that the solution concentration is the most important factor impacting the CA of electrospun fiber mat. The obtained results demonstrated that both the proposed models are highly effective in estimating the CA of electrospun fiber mat. However, more accurate results are obtained by the ANN model as compared to the RSM model. In the ANN model, the determination coefficient (R2) and relative error between actual and predicted response are obtained as 0.965 and 5.94%, respectively. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21365; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21365
Minor‐phase particles evolution in a polyethylene/ethylene–propylene copolymer (80/20) blend across mixing: Breakup and coalescence
Authors: Chen Xu‐Huang , Yu Peng , Kostromin Sergei , Bronnikov Sergei
Published: June 2013

On the basis of an online sampling microscopy method, the morphological evolution of a metallocene polyethylene/metallocene ethylene–propylene copolymer system (80/20 vol %) across various mixing regimes was investigated and treated statistically. The size distributions of the minor‐phase metallocene ethylene–propylene (mEP) droplets were described with principles of irreversible thermodynamics. Such an approach allowed us to find two superimposed statistical ensembles involving primary (broken) and secondary (coalesced) mEP particles. The mean size and relative number of both broken and coalesced mEP particles were calculated. The evolution of these characteristics across melt mixing, static coalescence, and flow‐driven coalescence was analyzed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3421–3431, 2013
Ion‐conductivity study and anomalous diffusion analysis of plasticized gelatin films
Authors: Basu Tania , Middya T. R. , Tarafdar Sujata
Published: June 2013

In this article, we report a study on ion conduction in gelatin films with different concentrations of glycerol as a plasticizer; these films might be a candidate for electrolyte materials in solid polymer batteries. The ion conductivity was appreciable, showing a maximum of about 9.14 × 10−3 S/m at room temperature without the addition of any ionic salt. Analysis of the impedance measurements was done with a model based on material properties instead of the usual equivalent circuit formalism, where circuit elements are difficult to interpret. Generalized calculus was used to model the anomalous diffusion in the system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3018–3024, 2013
Synthesis, characterization, and fluorescence properties of aniline‐g‐poly(styrene‐co‐maleic anhydride) and its lanthanide complexes
Authors: Liu Min , Yin Handi , Yang Ying , Huang Yong
Published: June 2013

Copolymers of aniline‐g‐poly(styrene‐co‐maleic anhydride) (AP/SMA) and its lanthanide(III) (Ln) ion complexes [Ln–AP/SMA (where Ln = La, Eu, Tb, or Yb)] were synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy, 1H‐NMR analysis, thermogravimetry–differential thermal analysis, and differential scanning calorimetry. At room temperature, the fluorescence spectra showed that the AP/SMA polymer had a strong, broad emission band at 300–550 nm (maximum wavelength = 381 nm) under excitation at 293 nm. Moreover, the respective characteristic emissions of Eu(III) and Tb(III) ions were observed in their Ln(III) complexes. Both the Eu(III) complexes and Tb(III) complexes showed excellent solvent resistance, good thermal stability, high quantum yield, and a long fluorescent lifetime. Therefore, the AP/SMA polymer and the fluorescent Ln–AP/SMA complexes have a promising future in applications of fluorescence materials. In addition, the reaction spontaneously reached equilibrium only after 5 min in the water phase; this showed that AP/SMA has good application prospects in the adsorption of Ln ions. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3432–3439, 2013
Characterization of the viscoelastic behavior of the pure bitumen grades 10/20 and 35/50 with macroindentation and finite element computation
Authors: Hamzaoui Rabah , Guessasma Sofiane , Bennabi Abdelkrim
Published: June 2013

In this article, we present an identification procedure that allows the determination of the viscoelasticity behavior of different grades of pure bitumen (bitumen 35/50 and bitumen 10/20). The procedure required in the first stage a mechanical response based on macroindentation experiments with a cylindrical indenter. A finite element simulation was performed in the second stage to compute the mechanical response corresponding to a viscoelasticity model described by three mechanical parameters. The comparison between the experimental and numerical responses showed a perfect matching. In addition, the identification procedure helped to discriminate between different bitumens characterized by different asphaltene and maltene contents. Finally, the developed procedure could be used as an efficient tool to characterize the mechanical behavior of the viscoelastic materials, thanks to the quantified relationship between the viscoleastic parameters and the force–penetration response. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3440–3450, 2013
Development of polylactide open‐cell foams with bimodal structure for high‐acoustic absorption
Authors: Mosanenzadeh Shahrzad Ghaffari , Naguib Hani E. , Park Chul B. , Atalla Noureddine
Published: June 2013

In this study, a highly porous and interconnected foam structure was fabricated using compression molding combined with particulate‐leaching technique. The foamed structures were fabricated with polylactide (PLA) and polyethylene glycol (PEG) with salt as the particulate. The pore size of the foam structure is controlled by the particulates size and higher interconnectivity is achieved by the co‐continuous blending morphology of the PLA matrix with the water‐soluble PEG. PLA is a fully bio‐based thermoplastic polymer and is derived from renewable resources, such as cornstarch or sugarcanes. PEG is also fully biodegradable polymer produced from ethylene. Fabricated foams were characterized for cellular, acoustic, and mechanical properties. The acoustic performance of the foams was studied by measuring the normal incident absorption coefficient in accordance with the ASTM E1050 standard. The results show open porosity as high as 88% was achieved and the effect of water‐soluble polymer on cellular properties and acoustic and mechanical performance of the foams was studied. As a result of the secondary porous structure formed into cell walls by water soluble polymer, the overall absorption of fabricated PLA foams was increased to above 90% while the average absorption of the foams remained unchanged. In addition, the resulting acoustic foams are benign and environmentally friendly. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39518.
Synthesis of wheat straw composite superabsorbent
Authors: Wan Tao , Huang Runqiu , Zhao Qihua , Xiong Lei , Qin Lili , Tan Xuemei , Cai Guojun
Published: June 2013

A novel wheat straw composite superabsorbent was prepared by graft polymerization with acrylic acid (AA), acrylamide (AM), and maleic anhydride‐modified wheat straw in aqueous solution, using N,N‐methylene‐bis‐acrylamide (MBA) as a cross‐linker and ammonium persulfate (APS) and sodium bisulfite (SBS) as redox initiators. Factors influencing the degree of carboxylation, such as reaction time, reaction temperature, and the amount of maleic anhydride, were investigated. Morphologies and structure of the wheat straw composite superabsorbent were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and X‐ray diffraction (XRD). Water absorption of wheat straw composite superabsorbent was rapid, requiring 13.1 min to reach 63% of equilibrium absorbency (781 g/g). FTIR spectra indicate that maleic anhydride has been reacted onto the wheat straw backbone and the structure of wheat straw graft copolymer is formed. SEM data show that the fibrous morphology of wheat straw disappears and gel aggregates with many large microporous holes are formed after wheat straw graft modification. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3404–3410, 2013
Biocomposite membranes of sodium alginate and silk fibroin fibers for biomedical applications
Authors: de Moraes Mariana Agostini , Beppu Marisa Masumi
Published: June 2013

Biocomposite membranes from biodegradable and biocompatible natural polymers were prepared from sodium alginate solution reinforced with silk fibroin fibers in several fiber content by casting and solvent evaporation. The properties of these biocomposites were investigated by scanning electron microscopy, swelling test, water vapor transmission, mechanical and thermal analyses, and cytotoxicity test. A biocomposite with uniform fiber dispersion and good fiber–matrix interaction was obtained through the incorporation of fibroin fibers in the alginate membrane, even though the fibers were used without any surface treatment to enhance the interfacial adhesion. The incorporation of fibroin fibers improved the tensile strength and also provided a new property to the alginate, that is, the resistance to tear. Moreover, the use of silk fibroin fibers in polymeric composites can result in a material with adequate characteristics for application in the biomaterial field, especially as wound dressings, because of its nontoxic effect to cells, flexibility, and resistance to tear. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3451–3457, 2013
Modeling of the atom transfer radical polymerization for preparing novel fluorosilicone diblock copolymers in a semi‐batch reactor
Authors: Huang Yao , Zhou Yin‐Ning , Zhang Qing , Luo Zheng‐Hong
Published: June 2013

To investigate the process for the preparation of well‐defined poly‐dimethylsiloxane‐b−2,2,3,3,4,4,4‐heptafluorobutylmetharylate block copolymers via a macroinitiator initiated atom transfer radical polymerization (ATRP), a model for the batch and semi‐batch ATRP process was presented based on the method of moments. The ATRP mechanism, the diffusion limitation, and the reactor choice were considered in the model. Besides, the polymer molecular weight, monomer conversion, and polymer polydispersity index as a function of polymerization time were described by this model. The model was validated by comparing simulated results with experimental data and was also used to investigate the effects of diffusion limitation and reactor choice (i.e., batch and semi‐batch reactors). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3473–3481, 2013
Stereoselective partitioning of organic substrates by thermoresponsive polymers in aqueous phases
Authors: Uemukai Toru , Torisaki Masashi , Hamanaka Takahiro , Ishifune Manabu
Published: June 2013

Partitioning of organic substrates by thermoresponsive polymer having N‐acryloylaminoalcohol moieties in aqueous phase has been studied. Thermoresponsive polymers, such as poly(N‐isopropylacrylamide) (PNIPAAm) and poly(NIPAAm‐co‐N‐acryloyl‐(±)‐alaninol) (poly(NIPAAm‐co‐HIPAAm)), were found to concentrate several organic substrates into the hydrophobic field generated during their phase transition. The amount of the substrates recoverd from the polymer phase mainly depended on the hydrophobicity of the substrates. Aqueous solutions of PNIPAAm (lower critical solution temperature, LCST = 33°C) and poly(NIPAAm‐co‐HIPAAm) (LSCT = 41°C) containing 1‐phenylethanol showed LCSTs at 22°C and 33°C, respectively. The changes of LCSTs indicate that specific interactions such as hydrogen bonding between the side chain functionalities of the polymers and the substrates influence the phase transition behavior. Moreover, new optically active polymers having chiral aminoalcohol moieties have been synthesized by copolymerizations of NIPAAm with N‐acryloylaminoalcohols such as N‐acryloyl‐(S)‐alaninol and N‐acryloyl‐(S)‐prolinol. The (R)/(S) ratio of 1‐phenylethanol recovered from poly(NIPAAm‐co‐N‐acryloyl‐(S)‐alaninol) and poly(NIPAAm‐co‐N‐acryloyl‐(S)‐prolinol) were determined to be 75/25 and 68/32, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3458–3464, 2013
Effect of aromatic additives with various alkyl groups on orientation birefringence of cellulose acetate propionate
Authors: Nobukawa Shogo , Aoki Yoshihiko , Yoshimura Hiroshi , Tachikawa Yutaka , Yamaguchi Masayuki
Published: June 2013

Orientation birefringence and its wavelength dispersion in blends of cellulose acetate propionate (CAP) and aromatic additive molecules having various alkyl chains were investigated, in order to evaluate the effect of the chemical structure on the optical properties. We found that the additive improved the orientation birefringence of CAP, meaning that the additive orientation is parallel to CAP chains via the “nematic interaction (NI)” reflecting the intermolecular orientation correlation. The NI strength was evaluated by using a theory concerning the molecular orientation. The result demonstrates that the alkyl chain length in the additive molecule strongly affects the orientation correlation. Although the intrinsic birefringence monotonically decreases with the alkyl chain length, the NI strength shows the highest value between the additive with propionyl group and CAP. From the result, the contribution of birefringence from the aromatic molecule, which is determined by the intrinsic birefringence and orientation function, needs to be considered to design the optical films with high performances. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3465–3472, 2013
Structure, properties, and mechanism of reactive compatibilization of epoxy to polyphenylene sulfide/polyamide elastomer
Authors: Gui Hao , Zhou Tao , Li Lin , Zhou Ting , Liu Feiwei , Zhan Yanhui , Zhang Aimin
Published: June 2013

In this article, the structure, properties, and mechanism of reactive compatibilization of epoxy (EP) to polyphenylene sulfide (PPS)/polyamide elastomer (PAe) were investigated in detail. A PPS/PAe/EP ternary system was successfully prepared via reactive extrusion. Its mechanical and rheological properties were greatly improved compared with those of conventional PPS/PAe binary system. The addition of EP to PPS/PAe blend induced a series of chemical reactions. The chain‐extended reaction of PPS was verified by high pressure capillary rheometer. The grafting reaction of PPS with PAe was testified by FTIR. The curing reaction of EP was proposed to explain the decreasing of the mechanical properties in PPS/PAe/EP ternary blend when it contained a high content of EP. Additionally, a toughened model was also proposed in PPS/PAe/EP ternary system. The improvement of toughness was attributed to the activation of matrix molecules in the shear band region. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3411–3420, 2013
The Dynamics of Lysozyme from Bacteriophage Lambda in Solution Probed by NMR and MD Simulations
Authors: Smith Lorna J. , Bowen Alice M. , Di Paolo Alexandre , Matagne André , Redfield Christina
Published: June 2013

15N NMR relaxation studies, analyses of NMR data to include chemical shifts, residual dipolar couplings (RDC), NOEs and HN–Hα coupling constants, and molecular dynamics (MD) simulations have been used to characterise the behaviour of lysozyme from bacteriophage lambda (λ lysozyme) in solution. The lower and upper lip regions in λ lysozyme (residues 51–60 and 128–141, respectively) show reduced 1H–15N order parameters indicating mobility on a picosecond timescale. In addition, residues in the lower and upper lips also show exchange contributions to T2 indicative of slower timescale motions. The chemical shift, RDC, coupling constant and NOE data for λ lysozyme indicate that two fluctuating β‐strands (β3 and β4) are populated in the lower lip region while the N terminus of helix α6 (residues 136–139) forms dynamic helical turns in the upper lip region. This behaviour is confirmed by MD simulations that show hydrogen bonds, indicative of the β‐sheet and helical secondary structure in the lip regions, with populations of 40–60 %. Thus in solution λ lysozyme adopts a conformational ensemble that will contain both the open and closed forms observed in the crystal structures of the protein.
Quellungsexperimente mit Superabsorber‐Polymeren
Authors: Granz Jessica , Maulbetsch Christoph
Published: June 2013

Die Quellungskinetik von Superabsorbern‐Polymeren (SAP) kann auf verschiedene Weise gemessen werden. Wir haben drei in der Literatur beschriebene Methoden auf ihre Verwendbarkeit im Chemieunterricht getestet. Die verschiedenen Methoden ergeben alle vergleichbare Sättigungsfunktionen für die Quellung und können zur Charakterisierung von SAP oder als einfache Beispiele in der Kinetik eingesetzt werden.

Swelling kinetics of superabsorbent polymers (SAP) can be measured by different experimental techniques. Three of these methods (filter, tea bag weight method and VIS spectrometry) were checked for their usefulness as experiments in chemistry classes. All experiments reproducibly yielded a saturation function for the swelling kinetics and can either be used to characterize SAP or to demonstrate simple kinetics.
Higher homocysteine and lower betaine increase the risk of microangiopathy in patients with diabetes mellitus carrying the GG genotype of PEMT G774C
Authors: Chen Li , Chen Yan‐ming , Wang Li‐jun , Wei Jun , Tan Yao‐zong , Zhou Jing‐ya , Yang Yang , Chen Yu‐ming , Ling Wen‐hua , Zhu Hui‐lian
Published: June 2013

Background

Diabetes represents one of the greatest medical and socioeconomic threats worldwide. The pathogenesis involved is complicated. The effect of methyl donors and genetic polymorphisms in metabolic enzymes on the risk of microangiopathy in patients with diabetes is not well understood. This study investigates the association of homocysteine, choline and betaine levels and phosphatidylethanolamine N‐methyltransferase (PEMT) G774C (rs12325817) genotypes with the risk of diabetes and its related microangiopathic complications.

Methods

Between January 2009 and June 2010, 184 diabetic patients and 188 non‐diabetic control subjects were enrolled in the hospital‐based case‐control study. Serum concentrations of betaine and choline were determined by high‐performance liquid chromatography (HPLC)–mass spectrometry. Serum concentrations of homocysteine were assayed using HPLC. PEMT gene mutations were detected by polymerase chain reaction and restriction fragment length polymorphism.

Results

After adjustment for potential confounders, serum total homocysteine had a significant dose‐dependent positive association, and serum choline had an inverse association with the risks of diabetes and its microangiopathic complications (both p < 0.001). Although serum betaine was not associated with the risk of diabetes, it had a significant inverse association with diabetic microangiopathy. Compared with GG genotype, the CC genotype of PEMT G774C was associated with a decreased risk of diabetes (OR 0.559, 95% CI 0.338, 0.926) and its microangiopathy (OR 0.452, 95% CI 0.218, 0.937).

Conclusion

The GG genotype of the PEMT G774C polymorphism, higher levels of serum homocysteine and lower levels of serum betaine are associated with an increased risk of microangiopathy in patients with diabetes. Copyright © 2013 John Wiley & Sons, Ltd.
The First Combined Experimental and Theoretical Evaluation of Tetravalent Cation Conduction in a Solid
Authors: Nunotani Naoyoshi , Tamura Shinji , Imanaka Nobuhito
Published: June 2013

Tetravalent tellurium ion conduction in solids has been demonstrated in α‐Te2MoO7 by both experimental and theoretical means for the first time. Although it has been commonly considered that the Te4+ ion will not conduct appreciably in solids due to its high valency, such conduction can be successfully achieved in solid α‐Te2MoO7, which has a 2D layered structure conducive to ion migration. The measured Te4+ ion conductivity in solid α‐Te2MoO7 (1.0 × 10–2 S cm–1 at 530 °C) reaches the threshold required for practical applications. Evidence for Te4+ ion conduction in α‐Te2MoO7 is provided both directly by DC electrolysis results and theoretically by MEM analysis.
A Family of Homologous Heterospin Complexes Based on Lanthanides and Biradical Ligands
Authors: Tian Li , Sun Ya‐Qiu , Na Bo , Cheng Peng
Published: June 2013

Four complexes based on rare earth biradicals [Ln(hfac)3(NITPhmbis)2]2 {Ln = La (1), Nd (2), Gd (3), Tb (4); hfac = hexafluoroacetylacetone; NITPhmbis = [1,3‐bis(1′‐oxyl‐3′‐oxido‐4′,4′,5′,5′‐tetramethyl‐4,5‐hydro‐1H‐imidazol‐2‐yl)benzene]} were successfully synthesized under appropriate conditions. Single‐crystal structures show that 1 is a mononuclear two spin complex and 2–4 are mononuclear three spin complexes, in which a NITPhmbis molecule acts as a bidentate ligand with one coordinated lanthanide ion. The four complexes are isomorphous, the coordination number around the lanthanide ion is eight, and the polyhedron is a 4,4‐bicappped trigonal prism. For lanthanum(III) complex 1, the temperature dependence of the magnetic susceptibility indicates that weakly antiferromagnetically coupled radicals exist (Jrad–rad = –1.2 cm–1). In the case of neodymium(III) complex 2, its magnetic behavior gives antiferromagnetic NdIII–radical interactions, whereas for complexes 3 and 4, static magnetic properties show that the GdIII and TbIII ions interact ferromagnetically with the radical. The dynamic magnetic properties of 4 were also measured, and 4 was found to exhibit slow relaxation of the magnetization at low temperature.
Forecasting Call Centre Arrivals
Authors: Millán‒Ruiz David , Hidalgo J. Ignacio
Published: June 2013

This article presents a novel neural network‒based approach to the intra‒day forecasting of call arrivals in call centres. We apply the method to individual time series of arrivals for different customer call groups. To train the model, we use historical call data from three months and, for each day, we aggregate the call volume in 288 intervals of 5 minutes. With these data, our method can be used for predicting the call volume in the next 5‒minute interval using either previous real data or previous predictions to iteratively produce multi‒step‒ahead forecasts. We compare our approach with other conventional forecasting techniques. Experimental results provide factual evidence in favour of our approach. Copyright © 2013 John Wiley & Sons, Ltd.
Orographic precipitation in valley network headwaters: Constraints on the ancient Martian atmosphere
Authors: Scanlon Kathleen E. , Head James W. , Madeleine Jean‐Baptiste , Wordsworth Robin D. , Forget François
Published: June 2013

We examine the Martian valley networks in the framework of topographic influences on precipitation. We use an analytical model and the Laboratoire de Météorologie Dynamique (LMD) early Mars global circulation model (GCM) to explore the local‐scale distribution of orographically forced precipitation as a function of atmospheric pressure. In simulations with 500 mbar and 1 bar CO2 atmospheres, orographic lifting results in enhanced snowfall upslope of the observed valley network tributaries. Our framework also suggests that a 2 bar atmosphere cannot create the observed valley pattern at the highest‐relief valley network, Warrego Valles. As in previous work, the GCM does not generate temperatures warm enough for rain or significant snowmelt in the highlands with CO2 greenhouse warming alone. Thus while transient periods of unusual warming are still required to melt the deposits and carve the valleys, our model predicts snow deposition in the correct locations.
Exploring hydroclimatic change disparity via the Budyko framework
Authors: van der Velde Ype , Vercauteren Nikki , Jaramillo Fernando , Dekker Stefan C. , Destouni Georgia , Lyon Steve W.
Published: June 2013

The Budyko framework characterizes landscape water cycles as a function of climate. We used this framework to identify regions with contrasting hydroclimatic change during the past 50 years in Sweden. This analysis revealed three distinct regions: the mountains, the forests, and the areas with agriculture. Each region responded markedly different to recent climate and anthropogenic changes, and within each region, we identified the most sensitive subregions. These results highlight the need for regional differentiation in climate change adaptation strategies to protect vulnerable ecosystems and freshwater resources. Further, the Budyko curve moved systematically towards its water and energy limits, indicating augmentation of the water cycle driven by changing vegetation, climate and human interactions. This finding challenges the steady state assumption of the Budyko curve and therefore its ability to predict future water cycles. Copyright © 2013 John Wiley & Sons, Ltd.
Influence of pig manure biochar mineral content on Cr(III) sorption capacity
Authors: Wnetrzak Renata , Leahy J.J. , Chojnacka Katarzyna W. , Saeid Agnieszka , Novotny Etelvino , Jensen Lars Stoumann , Kwapinski Witold
Published: June 2013

BACKGROUND

The adsorption of Cr(III) ions on various pig manure biochar (BC) samples was investigated to determine the effect of operating conditions (initial pH, sorbate and sorbent concentrations) on sorptive capacity. The BC samples with higher sorption capacity showed high surface area and were rich in alkaline metals whose concentration was measured by ICP‐OES.

RESULTS

For BCs from anaerobically and chemically pretreated feedstock greater ΔpH changes and higher maximum capacity were noted during Cr(III) adsorption than for BC from mechanically pretreated samples, due to a higher ion exchange capacity. The maximum Cr(III) uptake of 102 mg g‐1 for the BC sample was achieved at c0 = 300 mg dm‐3 and pH = 5. It was also observed that the high ash content effectively lowered the surface area of BCs; however all BCs investigated contained a low level of toxic metals.

CONCLUSIONS

The data indicate that both the technology used for separation of the manure and pyrolysis temperature had a significant influence on the physical and chemical properties of the BC and affected its sorption capacity. In addition, compared with other sorbents pig manure BC has one of the best Cr(III) sorption capacities. © 2013 Society of Chemical Industry