bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ageing studies on some titania gels
Authors: Ragai Jehane 
Published: July 2010

AbstractHydrous titania gels, precipitated from titanous chloride and aged in different aqueous media have different textural, thermal and structural properties as demonstrated by nitrogen adsorption, differential thermal analysis, X‐ray diffraction and scanning electron microscopy studies. Ageing in ammonia leads to the development of microporosity, whereas ageing in water causes an extension of the pore system in the primary particles with little change in the surface texture. Heat‐treatment of the precipitated gels prior to ageing seems to afford a certain stability to the primary particle by allowing hydroxo and oxo bridges to be formed, thus leading to the formation of a more rigid structure. The nature of the ageing medium and its effect on the inner coordination sphere of the titanium ions are important parameters affecting the textural and thermal behaviours of the titania gels.
A simplified model for the correlation of vapour‐liquid equilibrium in the CO2‐NH3‐H2O system
Authors: Paunović Ratomir , Petkovska Menka , Krnić Zoran , Ćirić‐Matijević Gordana 
Published: July 2010

AbstractA new simplified VLE model of the CO2‐NH3‐H2O system under conditions of the distillation and absorption steps of the recycle urea process is developed. For the gaseous phase the virial state equation is adopted and the component activity coefficients are approximated by a simple linear expression. The resulting equations for the equilibrium constants of the physical and chemical equilibria are fitted to experimental values (in the literature) within the temperature range of 307 to 414 K and within the pressure range of 2 to 40 bar. Tests of the model on the experimental data are presented as well as the comparisons with other published simplified VLE models of the system.
Bioactivity of antifouling paints based on organotin toxicants
Authors: Benítez Juan Carlos , Giúdice Carlos A. , Rascio Vicente J. D. 
Published: July 2010

AbstractThis paper discusses the bioactivity of antifouling paints based on organotin toxicants, such as tributyltin fluoride (TBTF) and triphenyltin fluoride (TPTF). These compounds were used alone or mixed as the main toxicant in formulations. The use of TPTF or mixtures of TPTF and TBTF, with vinyl binders, led to paints with satisfactory bioactivity during a 24 months immersion period. With the same binders, TBTF alone provided only 12 months of antifouling protection. The correlation coefficients calculated from the fouling attachment values and the rosin content in the binder showed that the bioactivity of the tested formulations depended on the solubility of the toxicant in sea water and on the composition and solubility of the binders.
The growth behaviour of Azotobacter chroococcum in association with some microorganisms in the soil
Authors: Elwan S. H. , El‐Naggar M. R. 
Published: July 2010

AbstractAn investigation was made on the role of microorganisms in affecting the growth behaviour of Azotobacter in the soil. Azotobacter chroococcum, Bacillus licheniformis, B. megaterium, Pseudomonas striata, Aspergillus niger, A. terreus, A. flavus, A. sydowi, A. nidulans, Fusarium sp., and Helminthosporium sp. were isolated from a sandy neutral soil. This soil was sterilized, one lot was kept as such, and another was supplemented with glucose and potassium phosphates. Azotobacter chroococcum was inoculated alone or in association with any of the above microorganisms. Counts of Azotobacter were made weekly during 14 weeks on nitrogen‐free agar plates.The results indicated the importance of the microbiological factor in affecting the growth behaviour of Azotobacter in the soil. A general pattern was observed showing a great decline for one week followed by a progressive increase more in non‐supplemented than in supplemented soils. In case of A. niger, however, a tendency of a decline was observed in the last 2 weeks.The discussion showed that the variation of the microflora of different soils or the nonstationary microbial balance of a soil may contribute to the controversy of the results of the investigations of Azotobacter behaviour in the soil.
Beziehungen zwischen Carboxin‐Resistenz und glykolytischer Potenz bei Pilzen
Authors: Ritter G. , Kluge E. , Lyr H. 
Published: July 2010

83 fungal species were tested for their correlation between carboxin sensitivity and glycolytic ability regarding the taxonomic position of the test fungi.Besides basidiomycetes the ascomycetous orders Helotiales, Sordariales, Chaetomiales, and Dothiorales showed carboxin sensitivity which was coupled with lacking fermentation and acid production while carboxin resistant taxa as a rule behaved vice versa. Furthermore, hexose monophosphate participation was high and phosphofructokinase activity was low in carboxin sensitive fungi.It is concluded that response to carboxin and glucose metabolism are coupled characters but without strict causal connection. In yeast‐like fungi carboxin sensitivity may indicate their taxonomic position within the basidiomycetes.
Salt stimulated respiration and ion transport of Chlorella fusca
Authors: Löppert H. G. 
Published: July 2010

AbstractRespiration has been measured in the dark before and after addition of salts to suspensions of Chlorella in distilled water. An immediate and marked, but transient, increase in oxygen uptake rate was observed with several alkali (Na, K, Rb) and heavy metal (Zn, Ce) salts. Comparison of this salt stimulated respiration (S.S.R.) with ion flux rates showed that, in contrast to higher plant cells, with Chlorella no simple relationship exists between S.S.R. and rate of salt uptake. An osmotic effect and direct action of salts with mitochondrial electron transport were excluded as causes of S.S.R. More likely, salt stimulated ATP hydrolysis at the plasmalemma acts upon electron flow to oxygen via respiratory control.
Biochemical studies on sporulation in blue‐green algae II. Factors affecting glycogen accumulation
Authors: Kanta Swarn , Sarma T. A. 
Published: July 2010

AbstractInorganic nitrogen sources like nitrate, nitrite enhanced sporulation and glycogen accumulation in Anabaena sp. but ammonium chloride neither influenced sporulation nor glycogen accumulation. Acetate and citrate also stimulated early sporulation and glycogen level was higher over nitrogen free control. Nitrogen and carbon sources in combination proved to be useful in inducing early sporulation and increased content of glycogen. Phosphate and calcium also affected glycogen accumulation significantly, although, the sporulation was found to be of the same order as in nitrogen free medium. Sulphate initiated early sporulation, the mechanism of which is not known.
Determination of a control function in three‐dimensional parabolic equations by Legendre pseudospectral method
Authors: Shamsi M. , Dehghan Mehdi 
Published: July 2010

AbstractA Legendre pseudospectral method is proposed for solving approximately an inverse problem of determining an unknown control parameter p(t) which is the coefficient of the solution u(x, y, z, t) in a diffusion equation in a three‐dimensional region. The diffusion equation is to be solved subject to suitably prescribed initial‐boundary conditions. The presence of the unknown coefficient p(t) requires an extra condition. This extra condition considered as the integral overspecification over the spacial domain. For discretizing the problem, after homogenization of the boundary conditions, we apply the Legendre pseudospectral method in a matrix based manner. As a results a system of nonlinear differential algebraic equations is generated. Then by using suitable transformation, the problem will be converted to a homogeneous time varying system of linear ordinary differential equations. Also a pseudospectral method for efficient solving of the resulted system of ordinary differential equations is proposed. The solution of this system gives the approximation to values of u and p. The matrix based structure of the present method makes it easy to implement. Numerical experiments are presented to demonstrate the accuracy and the efficiency of the proposed computational procedure. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 74‐93, 2012
Synthesis and characterization of thermoresponsive poly(ethylene glycol)‐based hydrogels and their magnetic nanocomposites
Authors: Meenach Samantha A. , Anderson Kimberly W. , Hilt J. Zach 
Published: July 2010

AbstractTemperature‐responsive hydrogels are one of the most widely studied types of stimuli‐responsive hydrogel systems. Their ability to transition between their swollen and collapsed states makes them attractive for controlled drug delivery, microfluidic devices, and biosensor applications. Recent work has shown that poly(ethylene glycol) (PEG) methacrylate polymers are temperature‐responsive and exhibit a wide range of lower critical solution temperatures based on the length of ethylene glycol units in the macromer chain. The addition of iron oxide nanoparticles into the hydrogel matrix can provide the ability to remotely heat the gels upon exposure to an alternating magnetic field (AMF). In this work, diethylene glycol (n = 2) methyl ether methacrylate and PEG (n = 4.5) methyl ether methacrylate copolymers were polymerized into hydrogels with 5 mol % PEG 600 (n = 13.6) dimethacrylate as the crosslinker along with 5 wt % iron oxide nanoparticles. Volumetric swelling studies were completed from 22 to 80 °C and confirmed the temperature‐responsive nature of the hydrogel systems. The ability of the gels to collapse in response to rapid temperature changes when exposed to an AMF was demonstrated showing their potential use in biomedical applications such as controlled drug delivery and hyperthermia therapy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3229–3235, 2010
Thiol‐isocyanate‐acrylate ternary networks by selective thiol‐click chemistry
Authors: Matsushima Hironori , Shin Junghwan , Bowman Christopher N. , Hoyle Charles E. 
Published: July 2010

AbstractThiol‐isocyanate‐acrylate ternary networks were formed by the combination of thiol‐isocyanate coupling, thiol‐acrylate Michael addition, and acrylate homopolymerization. This hybrid polymerization reaction sequence was preferentially controlled by using phosphine catalyst systems in combination with photolysis. The reaction kinetics of the phosphine/acrylate thiol‐isocyanate coupling reactions were systematically investigated by evaluating model, small molecule reactions. The thiol‐isocyanate reaction was completed within 1 min while the thiol‐acrylate Michael addition reaction required ∼10 min. Both thiol‐isocyanate coupling and thiol‐acrylate Michael addition reactions involving two‐step anionic processes were found to be both quantitative and efficient. However, the thiol‐isocyanate coupling reaction was much more rapid than the thiol‐acrylate Michael addition, promoting initial selectivity of the thiol‐isocyanate reaction in a medium containing thiol, isocyanate, and acrylate functional groups. Films were prepared from thiol‐isocyanate‐acrylate ternary mixtures using 2‐acryloyloxyethylisocyanate and di‐, tri‐, and tetra‐functional thiols. The sequential thiol‐isocyanate, thiol‐acrylate, and acrylate homopolymerization reactions were monitored by infrared spectroscopy during film formation, whereas thermal and mechanical properties of the films were evaluated as a function of the chemical composition following polymerization. The results indicate that the network structures and material properties are tunable over a wide range of properties (Tg ∼ 14–100 °C, FWHM ∼ 8–46 °C), while maintaining nearly quantitative reactions, simply by controlling the component compositions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3255–3264, 2010
Thermal stability of porous it‐PMMA thin film obtained by the extraction of st‐PMAA from it‐PMMA/st‐PMAA stereocomplex with layer‐by‐layer assembly on a substrate
Authors: Ajiro Hiroharu , Maegawa Masumi , Akashi Mitsuru 
Published: July 2010

AbstractThe functionality of porous isotactic (it) poly(methyl methacrylate) (PMMA) thin films, which were previously developed by the selective extraction of syndiotactic (st) poly(methacrylic acid) (PMAA) from the it‐PMMA/st‐PMAA stereocomplex thin film on a substrate using the layer‐by‐layer assembly method was investigated after thermal treatment (70, 80, and 90 °C) in water for 4 h. Quartz crystal microbalance analysis and infrared spectra measurements revealed that the st‐PMAA incorporation ability of the porous it‐PMMA thin film decreased in order at 80 and 90 °C, while there was no decrease observed at 70 °C. X‐ray diffraction analysis also supported the thermal stability of the porosity at 70 °C, whereas two it‐PMMA crystalline peaks (2θ = 9° and 14°) were generated during heating at 90 °C. The loss of the functionality of the it‐PMMA thin film was thus shown to be due to crystallization, which was caused by the increase in polymer‐chain mobility during the heating process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3265–3270, 2010
Synthesis of polymer microspheres functionalized with chiral ligand by precipitation polymerization and their application to asymmetric transfer hydrogenation
Authors: Haraguchi Naoki , Nishiyama Akihiro , Itsuno Shinichi 
Published: July 2010

AbstractMonodisperse, crosslinked poly(divinylbenzene) and poly(methacrylic acid‐co‐ethylene glycol dimethacrylate) microspheres with (1R,2R)‐N1‐toluenesulfonyl‐1,2‐diphenylethylene‐1,2‐diamine ((R,R)‐TsDPEN) moiety were successfully prepared by precipitation polymerization. Introduction site of the (R,R)‐TsDPEN moiety into the polymer microspheres could be controlled by changing the order of addition of the corresponding monomers. The functionalized polymer microspheres were applied to asymmetric transfer hydrogenation of ketone and imine. Polymer microsphere‐supported chiral catalysts showed good reactivity and enantioselectivity in the catalytic asymmetric transfer hydrogenations. Chiral secondary alcohol was quantitatively obtained with 94% ee in the asymmetric transfer hydrogenation of acetophenone in water. We also found that introduction site of the chiral catalyst and hydrophobicity of the microspheres, as well as degree of the crosslinking, affected the yield and enantioselectivity of chiral product in this reaction. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3340–3349, 2010
Synthesis, characterization, and properties of amphiphilic chitosan copolymers with mixed side chains by click chemistry
Authors: Yuan Weizhong , Zhao Zhengda , Gu Shuying , Ren Jie 
Published: July 2010

AbstractNovel amphiphilic chitosan copolymers with mixed side chains of poly(ε‐caprolactone) and poly(ethylene oxide) (CS‐g‐PCL/PEO) were successfully synthesized by “graft to” approach via click chemistry. The melting and crystallization behaviors and crystalline morphology of CS‐g‐PCL/PEO copolymers can be adjusted by the alteration of the feed ratio of PCL and PEO segments. CS‐g‐PCL/PEO copolymers revealed crystalline morphology different from that of linear alkynyl PCL and alkynyl PEO due to the influence of brush structure of copolymers and the mutual influence of PCL and PEO segments. The hydrophilicity of the CS copolymers can be improved and adjusted by the alteration of the composition of PCL and PEO segments. Moreover, the CS copolymers can self‐assemble into spherical micelles in aqueous solution. Investigation shows that the size of the CS copolymer micelles increased with the increase of the content of hydrophobic PCL segments in copolymers, which indicated that the micellar behavior of the copolymers can be controlled by the adjustment of the ratio of PCL and PEO segments in copolymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3476–3486, 2010
Thermoelasticity and conformational behavior of polyethylene and ethylene‐propylene copolymers
Authors: Opschoor A. , Prins W. 
Published: July 2010

AbstractForce‐temperature measurements at constant length and pressure are reported for amorphous, crosslinked networks of polyethylene and some ethylene‐propylene copolymers. The ratio of the energy contribution to the total tension, fe/f, calculated from these measurements and thermal expansion data, was found to depend strongly on the extension ratio as well as on the crosslink density. In current theory fe/fT is equal to the temperature coefficient of the unperturbed mean‐square end‐to‐end distance of the polymer chain in the network (d In (r02)/dT). The experimentally found nonconstancy of the fe/f makes it impossible to calculate a single value of d In (r20)/dT) for comparison with our a priori calculations of this quantity. These findings are at variance with previously published data of Flory, Ciferri, and Hoeve. Possibly, stress‐induced crystallization or, more generally, stress‐dependent intermolecular forces may play a role in thermoelas‐ticity studies under certain circumstances, in spite of the reversibility of the temperature cycles.
The decomposition mechanisms of xanthates of model compounds for cellulose. I. Xanthates of primary, secondary, and tertiary alcohols
Authors: Joedodibroto Roehjati , Rånby Bengt 
Published: July 2010

AbstractXanthates of methanol, ethanol, isopropanol and t‐butyl alcohol were prepared and purified. The decomposition of these xanthates in aqueous alkali solutions (NaOH and KOH) at different temperatures was studied by UV spectrophotometry at 300‐303 nm. The methyl, ethyl, and isopropyl xanthates decomposed without salt effect and showed increasing stability in this order. They appeared to decompose by a bimolecular reaction (addition of a hydroxyl ion to the xanthate group) according to an Sn2 mechanism. The t‐butyl xanthate decomposed at a much faster rate and with salt effect, apparently by a monomolecular reaction (dissociation of the xanthate to a t‐butyl carbonium ion and a dithiocarbonate ion) according to an Sn1 mechanism. The decomposition behavior of these model xanthates cannot explain the previous findings that xanthates of primary alcohols (e.g. on cellulose chains) are more stable than xanthates of secondary alcohols.
Fracture of polymers in biaxial and triaxial tension
Authors: Smith Thor L. 
Published: July 2010

AbstractMacroscopic fracture is preceded by localized deformation and rupture processes that depend on the state of combined stress (i.e., on the stress state) and other test conditions as well as on polymer structure and morphology. To illustrate the effect of stress state on the mode of fracture initiation and crack growth, data obtained on elastomers in triaxial tension are reviewed along with those for an unfilled styrenebutadiene rubber vulcanizate in simple tension, equal biaxial tension, and under the biaxial tensile conditions that give a pure shear deformation. The behavior of plastics, including the dependence of the strength of a notched specimen on its thickness, is briefly considered.
Structural changes of drawn polyacrylonitrile during annealing
Authors: Hinrichsen Georg 
Published: July 2010

AbstractFibers and solvent‐cast films of polyacrylonitrile have been investigated by x‐ray small‐angle and wide‐angle measurements and dynamic‐mechanical analysis. It has been found that the structure of this polymer is better described by a two‐phase model consisting of more and less ordered regions. By the aid of x‐ray methods, transition temperatures have been observed; there are indications that the molecules within the ordered regions are responsible for motion mechanisms. By annealing, the colloidal structure and thereby the mechanical behavior is influenced.
RAMEA: how to support regional policies towards sustainable development
Authors: Sansoni Michele , Bonazzi Elisa , Goralczyk Malgorzata , Stauvermann Peter J. 
Published: July 2010

AbstractA Regional Accounting Matrix including Environmental Accounts (RAMEA) is the Regional version of a ‘National Accounting Matrix including Environmental Accounts’ (NAMEA), an environmental accounting system that combines economic and environmental accounts into a single framework, which is useful for the evaluation and comparison of the integrated economic–environmental–social performance of regions. Presenting the first results of compiling and applying a RAMEA in three European regions: Emilia‐Romagna (Italy), Noord‐Brabant (the Netherlands) and Małopolska (Poland), this paper analyses the difficulties in achieving internationally comparable regional models. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
Hearing loss in Pompe disease revisited: results from a study of 24 children
Authors: van Capelle Carine I. , Goedegebure Andre , Homans Nienke C. , Hoeve Hans L. J. , Reuser Arnold J. , van der Ploeg Ans T. 
Published: July 2010

AbstractLittle information is available regarding the auditory function in Pompe patients. Hearing loss has been reported in classic infantile patients, but it is still unknown whether central nervous system involvement interferes with auditory function and whether enzyme replacement therapy can improve hearing. Auditory function has not been studied in children with milder forms of the disease. We analyzed repetitive auditory brainstem response measurements and pure tone audiometry in 24 children with Pompe disease. Only 1 of 13 patients with milder phenotypes showed recurrent conductive hearing loss, while 10 out of 11 classic infantile patients had sensorineural hearing defects. These patients also had a high prevalence of conductive hearing loss. Five patients showed evidence of mild retrocochlear pathology, suggestive of glycogen accumulation in the central nervous system. Hearing loss persisted during therapy in all patients. The results emphasize the need for careful monitoring of auditory function in classic infantile Pompe patients, and for early implementation of hearing aids to protect speech and language development.
Conservation study of Myrsine seguinii in Japan: current distribution explained by past land use and prediction of distribution by land use‐planning simulation
Authors: Vega Luis A. , Koike Fumito , Suzuki Makoto 
Published: July 2010

AbstractThe causes of the current distribution of a warm temperate tree Myrsine seguinii population were studied from topographic, geographical, and historical perspectives, and future land management to conserve this species. The study site is the Tokyo University forest located in Chiba Prefecture, at the northern distribution limit of this species. Presence and absence of individuals was surveyed in 10 × 10 m plots along the census line, making a total of 9,697 plots. The current distribution was modeled by multivariate logistic regression using environmental variables determined based on 10‐m mesh digital elevation model (elevation, slope, solar radiation, topographic wetness index, surface curvature), 1‐km mesh climatic information, and current (2005) and historic (1900) land‐use maps. It was clarified that the current distribution area coincides with a Pinus densiflora forest present by the end of the 19th‐century Meiji era, where 88.6% of individuals of M. seguinii were found. Inland suitable areas show small patches distributed among the ridges and mountainsides facing south, decreasing as the average monthly minimum winter temperature decreases. Simulated scenarios showed that in the future the potential distribution area of the studied species would decrease in the case of a complete coverage of Cryptomeria or Chamaecyparis plantation, and the case of evergreen broadleaf forest coverage would be better than these plantations. The strong effect of past land use suggests vulnerability and difficulty in the rapid recovery of M. seguinii population from human disturbance.