bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel microencapsulation of neem (Azadirachta Indica A. Juss.) seed oil (NSO) in polyelectrolyte complex of κ‐carrageenan and chitosan
Authors: Devi Nirmala , Maji T. K. 
Published: April 2009

AbstractMicrocapsules containing neem (Azadirachta Indica A. Juss.) seed oil (NSO) were prepared by encapsulation of natural liquid pesticide NSO in a polyelectrolyte complex of κ‐carrageenan and chitosan. The optimum ratio between carrageenan and chitosan to form a stable polyelectrolyte complex was found as 1 : 0.36. The microencapsulation method for NSO loading was also optimized. SEM study demonstrated that the surface of the microcapsules became more irregular as oil loading increased. The release rates of NSO were studied by varying the percentage of oil loading, concentration of cross‐linking agent, and polymer concentration. Fourier transform infrared spectroscopy (FTIR) study confirmed the complex formation between κ‐carrageenan and chitosan. Differential scanning calorimetry (DSC) and FTIR study indicated the absence of any significant interaction between polyelectrolyte complex of κ‐carrageenan ‐chitosan and NSO. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of polymer glycols on micro‐aggregation structure and mechanical properties of spherulite size graded polyurethane elastomers
Authors: Kongpun Teerin , Kojio Ken , Furukawa Mutsuhisa 
Published: April 2009

AbstractSpherulite size graded polyurethane elastomers (PUEs) were prepared using a mold with a temperature gradient from different polymer glycols, 4,4′‐diphenylmethane diisocyanate (MDI) and a mixture of 1,4‐butanediol (BD), and 1,1,1‐trimethylol propane (TMP) as a curing agent by a prepolymer method. The used polymer glyocols were poly(oxytetramethylene)glycol (PTMG, Mn = 2000), poly(ethylene adipate)glycol (PEA, Mn = 2000), and poly(hexamethylene adipate)glycol (PHA, Mn = 2000). The effect of polyether and polyester glycols and the temperature gradient on the micro‐aggregation structure and mechanical properties were studied by polarized optical microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, micro‐hardness test, pulsed nuclear magnetic resonance spectroscopy, and tensile test. The prepared PUEs had spherulite size graded super‐structure. Spherulite sizes of the PUEs depended significantly on the temperature gradient of the mold. Spherulite of the PUEs in contact with the mold at low temperature was significantly smaller and more dense than that contacting the mold at high temperature. The spherulite diameter of PTMG‐, PEA‐, and PHA–PUEs changed from 12.6 to 16.3 μm, 8.4 to 15.6 μm, and 10.4 to 16.0 μm, respectively from the lower temperature side (LTS) toward the higher temperature side. In contrast, the number of spherulites became sparser toward the higher one. The glass transition temperature (Tg) of PTMG‐, PEA‐, and PHA‐based PUEs elevated from −55.3°C, −19.0°C and −33.8°C at the LTS to −48.6°C, −17.8°C and −32.8°C at the HTS, respectively. Tg of all PUEs exhibited elevation from the LTS toward the higher one. This result associated with the strong microphase separation of the LTS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and properties of liquid polycarbosilanes with hyperbranched structures
Authors: Huang Muhe , Fang Yunhui , Li Ran , Huang Tianhua , Yu Zhaoju , Xia Haiping 
Published: April 2009

AbstractLiquid polycarbosilanes substituted by unsaturated groups were prepared by a one‐pot synthesis with Cl2Si(CH3)CH2Cl, Cl3SiCH2Cl, and CH2CHCH2Cl (or HCCMgBr) as the starting materials. The as‐received polycarbosilanes were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance and were confirmed to have hyperbranched structures. The polymer yield, SiH content, side reaction, unsaturated group content, and polymer structure are affected by the amount of the starting materials in feed. The thermal properties of the polycarbosilanes were investigated by thermogarvimetric analysis. The ceramic yield of allyhydridopolycarbosilane is about 60% and that of ethynylhydridopolycarbosilane is over 75%, indicating that the liquid polycarbosilanes have great potential to be promising precursors to SiC. Moreover, the compositions of the polycarbosilanes and the final ceramics can be tailored by controlling the amount of the starting materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A stable porous superhydrophobic high‐density polyethylene surface prepared by adding ethanol in humid atmosphere
Authors: Yuan Zhiqing , Chen Hong , Tang Jianxin , Zhao Dejian 
Published: April 2009

AbstractA stable porous superhydrophobic high‐density polyethylene (HDPE) surface with water contact angle of 160.0 ± 1.9° and sliding angle of 2.0 ± 1.6° was obtained by adding ethanol in humid atmosphere at 5°C. Soaked in water with temperatures ranging from 5 to 50°C for 15 days, even suffering compressive forces, and the water contact angles were still higher than 150°. After water flowed through the surface continuously for 30 min, even water droplets with a diameter of 4 mm dropped onto the HDPE surface from 30 cm high for 10 min, the water contact angles were also higher than 150°. A brief explanation to the formation of the porous superhydrophobic HDPE surface was put forward. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Viscoelastic behavior of rubber under a complex loading
Authors: Suphadon N. , Thomas A. G. , Busfield J. J. C. 
Published: April 2009

AbstractIn the literature, the loss factor of an elastomer, expressed as tan δ, has been reported to decrease with strain. This has been interpreted as a lowering of the internal viscosity due to chain orientation under strain. This contrasts with experimental findings showing that up to large strains, loss modulus does not change with strain. These experiments show that, as measured, tan δ does decrease with strain. However, a simple analysis shows that this effect is due to geometric changes alone and that the essential viscoelastic behavior, expressed as the loss modulus, is constant with strain up to an extension of about 2 for the simple unfilled compounds investigated here. This article also shows that the prestrain does not induce any significant anisotropy in the loss modulus, at least up to an extension ratio of 2. This was measured by the stretching of a rubber sample by simple extension and then the subjection of the sample to free vibrations in either torsion or tension. By the measurement of the damping in this way, the anisotropy induced by the pre‐extension was measured. The experiments in this work were all conducted on unfilled natural rubber or styrene–butadiene rubber compounds, with 2 different natural rubber compounds being used to investigate the effect of the crosslink density. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation, morphologies, and properties of positively charged quaternized poly(phthalazinone ether sulfone ketone) nanofiltration membranes
Authors: Yan Chun , Zhang Shouhai , Liu Cheng , Yang Daling , Yang Fajie , Jian Xigao 
Published: April 2009

AbstractPositively charged quaternized poly(phthalazinone ether sulfone ketone) (QAPPESK) nanofiltration (NF) membranes were prepared from chloromethylated poly(phthalazinone ether sulfone ketone) by the dye/wet phase inversion method with N‐methyl‐2‐pyrrolidone (NMP) and N,N‐dimethylacetamide (DMAc) as solvents. The effects of the ratio of NMP to DMAc, the evaporation time, the evaporation temperature, and the coagulation temperature on membrane performance were evaluated by the orthogonal design method. The results showed that the optimal preparation conditions were an NMP/DMAc ratio of 2/8, an evaporation time of 5 min at 70°C, and a coagulation temperature lower than 5°C. The effects of the additive type and concentration on the QAPPESK NF membrane cross‐section morphology and performance were investigated in detail. Furthermore, QAPPESK NF membranes exhibited good thermal stability with stable membrane performance for 120 h at 60°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polyimide–polydimethylsiloxane copolymers for low‐dielectric‐constant and moisture‐resistance applications
Authors: Xi Kai , Meng Zhen , Heng Liang , Ge Renjie , He Hui , Yu Xuehai , Jia Xudong 
Published: April 2009

AbstractNovel, randomly coupled, soluble, segmented polyimide–polydimethylsiloxane (PI–PDMS) copolymers were prepared from aminoalkyl‐terminated polydimethylsiloxane (At–PDMS), 4,4′‐oxydianiline diamine, pyromellitic dianhydride, and 4,4′‐diphenylmethane diisocyanate (MDI). When At–PDMS was introduced into the polyimide chain, the polyimide copolymers exhibited lower dielectric constants and better moisture resistance and mechanical properties. The reductions in the dielectric constant of the PI–PDMS copolymers could be attributed to the incorporation of polydimethylsiloxane (PDMS) into the polyimide chain and the nanopores in the film generated by carbon dioxide evolvement during the reaction. The lowest dielectric constant was 2.58 with 25 wt % PDMS and 5 wt % MDI. In addition, the water contact angles of the resultant copolymers increased from 51 to 109° when the contents of PDMS increased from 0 to 25 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Sensitivity analysis of the moments of the profit on an Income Protection Policy
Authors: Cordeiro Isabel Maria , Magalhães Pedro Manuel 
Published: April 2009

AbstractThe main purpose of this paper is to perform a sensitivity analysis where we quantify and analyse the effects on the mean of the profit on an Income Protection policy and two risk measures of changing the values of the transition intensities. All the calculations carried out are based on a multiple state model for Income Protection proposed in Continuous Mortality Investigation Committee (Continuous Mortality Investigation Reports 1991; 12). Within this model, we derive a formula for the mean of the profit, which enables to evaluate it more efficiently. In order to calculate the two risk measures we use the numerical algorithms for the calculation of the moments of the profit proposed by Waters (Insurance: Mathematics and Economics 1990; 9:101–113). We carry out the sensitivity analysis considering two different situations: in the first situation, we update the premium rates used to calculate the moments of the profit, according to the changes in the values of the transition intensities; in the second one, we do not update the premium rates. Both analyses are of practical interest to insurance companies selling Income Protection policies. Copyright © 2009 John Wiley & Sons, Ltd.
Field optimization and CCD data simulation for the antarctic International Concordia Explorer Telescope (ICE‐T)
Authors: Fügner D. , Fuhrmann C. , Strassmeier K.G. 
Published: April 2009

AbstractWe performed extensive data simulations for the planned ultra‐wide‐field, high‐precision photometric telescope ICE‐T (International Concordia Explorer Telescope). ICE‐T consists of two 60 cm‐aperture Schmidt telescopes with a joint field of view simultaneously in two photometric bandpasses. Two CCD cameras, each with a single 10.3k × 10.3k thinned back‐illuminated device, would image a sky field of 65 square degrees. Given a location of the telescope at Dome C on the East Antarctic Plateau, we searched for the star fields that best exploit the technical capabilities of the instrument and the site. We considered the effects of diurnal air mass and refraction variations, solar and lunar interference, interstellar absorption, overexposing of bright stars and ghosts, crowding by background stars, and the ratio of dwarf to giant stars in the field. Using NOMAD, SSA, Tycho‐2 and 2MASS‐based stellar positions and BVIJH magnitudes for these fields, we simulated the effects of the telescope's point‐spread‐function, the integration, and the co‐addition times. Simulations of transit light curves are presented for the selected star fields and convolved with the expected instrumental characteristics. For the brightest stars, we showed that ICE‐T should be capable of detecting a 2 REarth Super Earth around a G2 solar‐type star, as well as an Earth around an M0‐star – if these targets were as abundant as hot Jupiters. Simultaneously, the telescope would monitor the host star's surface activity in an astrophysically interpretable manner (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recent observations of AB Dor and interpretation
Authors: Budding E. , Erdem A. , Innis J.L. , Oláh K. , Slee O.B. 
Published: April 2009

AbstractWe use minimal empirical modelling techniques to interpret recent (2006–2007) photometry and spectroscopy of AB Dor. We compare, in particular, broadband (B and V) maculation effects with emission features in high‐resolution Ca II K‐line spectroscopy. We also compare emission effects in the Ca II Kand Hα lines observed at different rotational phases. We refer to a broader multiwavelength campaign, of which these optical data were a part, involving X‐ray and microwave observations to be published later. The broadband light curves are characterized by one outstanding macula, whereas the emission lines suggest 4 possible main chromospheric activity sites (‘faculae’). These appear at a similar latitude and with comparable size to the main umbra, but there are significant displacements in longitude. However, one strong facular concentration near phase zero may have a physical relationship to the main macula. The derived longitudes of these features would have been affected by differential rotation operating over the several months between the spectroscopic and photometric observations, but the difference of at least ∼30° between facula and umbra appears too great to allow their coincidence. The possibility of a large bipolar surface structure is considered, keeping in mind the bipolar character of solar activity centres: the activity of rapidly rotating cool stars being generally compared with that of the Sun, scaled up by a few orders of magnitude. Observed microwave activity may link to this same main photospheric and chromospheric centre picked up by the optical analysis. Characterization of macular and facular contributions in stellar activity sites would be improved with a closer timing of observations and higher signal to noise ratios in emission line data (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The solar observations at Armagh Observatory in 1795–1797
Authors: Arlt R. 
Published: April 2009

AbstractThis article reports on solar observations by J.A. Hamilton and W. Gimingham at Armagh Observatory made in 1795–1797. A number of sunspot positions were obtained from the original observing notes, mostly from micrometer measurements. The period is particularly interesting for the understanding of the onset of the Dalton minimum and a possible minor cycle between the Cycles 4 and 5. For the same period, sunspot positions recorded by Staudacher were measured and published in an earlier paper (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new spectrofluorimetric method for determination of trace amounts histamine in human urine and serum
Authors: Peng Qian , He Jixiang , Jiang Chongqiu 
Published: April 2009

AbstractA new spectrofluorimetric method was developed for the determination of trace amounts of histamine in human urine and serum samples. In NaAc–HAc buffer solution of pH 4.0, histamine can react with the acetylacetone–formaldehyde system to produce a fluorescent derivative which emits yellow‐green fluorescence at 476 nm, according to the Hantzsch reaction, and the enhanced fluorescence intensity is in proportion to the concentration of histamine. Optimum conditions for the determination of histamine were also investigated. The dynamic range and detection limit for the determination of histamine is 5.96 × 10–8–1.50 × 10–5 mol/L and 4.35 × 10–8mol/L, respectively. This method is practical and can be successfully applied to determination of histamine in human urine and serum samples. A proposal of the reaction pathway is suggested. Copyright © 2009 John Wiley & Sons, Ltd.
A simple and fast detection technique for arsenic speciation based on high‐efficiency photooxidation and gas‐phase chemiluminescence detection
Authors: Xue Junhai , Zhu Zhenli , Zhang Sichun , Zhang Xinrong 
Published: April 2009

AbstractHigh‐efficiency photooxidation (HEPO) and gas phase chemiluminescence detection (CL) combined with high‐performance liquid chromatography (HPLC) and hydride generation were developed for speciation of As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). After chromatography separation, the arsenic species were passed through HEPO which performed efficient photooxidation and converted MMA and DMA to As(V) in several seconds. Then the reaction of ozone and arsine upon hydride generation produced a CL signal as the analytical parameter. The total analytical process was completed within 10 min. The effects of operational parameters such as the concentrations of hydrochloric acid and NaBH4 solution, carrier gas flow and air gas flow for ozone generation were investigated. Detection limits were 3.7, 10.3, 10.2 and 10.0 µg/L for As(III), As(V), MMA and DMA, respectively. The recoveries of the four arsenic species in human urine sample ranged from 87 to 94%. Copyright © 2009 John Wiley & Sons, Ltd.
A highly sensitive fluorescent probe for tiopronin based on the cleavage of 2, 4‐dinitrobenzenesulfonate
Authors: Wang Liping , Yang Xiao‐Feng , Xu Hongmei , Zhao Minglei 
Published: April 2009

AbstractA highly sensitive fluorogenic probe for tiopronin was proposed. 2,4‐Dinitrobenzenesulfonyl‐fluorescein (I) is an almost nonfluorescent compound. Upon mixing with tiopronin in aqueous solution, the 2,4‐dinitrobenzenesulfonyl group of I was efficiently removed and its parent dye fluorescein was released, hence leading to dramatic increases in both fluorescence and absorbance of the reaction mixture. Under optimal conditions, the fluorescence increase is linear with tiopronin concentration in the range 5.0–600 ng mL−1, with a detection limit of 1.5 ng mL−1 (3σ). The proposed method has been successfully applied to tiopronin determination in pharmaceutical preparations and in spiked human urine samples. Copyright © 2009 John Wiley & Sons, Ltd.
Soft‐modeling based spectrofluorimetric study of simultaneous equilibria
Authors: Abdollahi H. , Sajjadi S. M. 
Published: April 2009

AbstractA two‐way soft resolution method will fail when applied to a simultaneous equilibria system due to rank deficiency in its concentration profiles. Increasing the dimensionality of measurements from two‐way to three‐way data can be used to overcome this problem. Simultaneous dissociation of two weak acids is considered as a model for simultaneous equilibria. Three‐way data obtained from excitation–emission spectrofluorimetric monitoring of a pH‐metric titration is analyzed using a proper combination of well‐known soft‐modeling methods. Multivariate curve resolution‐alternating least squares is used for calculating the excitation and emission spectral profiles of involved species and rank annihilation factor analysis for obtaining the contribution of each species in measured excitation–emission matrices at different pHs. The results of simulated and real simultaneous acids dissociation equilibria showed that the proposed combined method performs well even in situation when the equilibrium constants are close to each other. The applicability of method for study of an acidic dissociation is also shown. Copyright © 2009 John Wiley & Sons, Ltd.
Sticky PCR: A PCR‐based protocol for targeted protein engineering
Authors: Yamabhai Montarop 
Published: April 2009

AbstractThis article describes a simple but powerful PCR‐based protocol for the generation of cohesive ends on linear DNA fragments, permitting the precise engineering of DNA constructs for a variety of applications. These include the introduction of deletion mutations, domain swapping, creating hybrid DNA fusions, or targeted protein engineering. This novel method can also facilitate the cloning of large or complex DNA fragments into a relevant cloning vector independent of the use of internal restriction endonuclease sites. The protocol involves the amplification of the required fragments by polymerase chain reaction through the use of two sets of overlapping desalted oligonucleotide primers. The subsequent mixing, denaturation and re‐annealing of these products present correct cohesive terminal ends for ligation. There is no requirement for special vectors, enzymes or bases, suggesting that this protocol provides a unique way of engineering constructs in a rapid and cost‐effective way for specific applications, such as precise deletion or swapping of various domains of the epidermal growth factor receptor to determine their role in membrane localization.
Regulatory effects of oxygen transfer on overexpression of recombinant benzaldehyde lyase production by Escherichia coli BL21 (DE3)
Authors: Kaya‐Çeliker Hande , Angardi Vahideh , Çalık Pınar 
Published: April 2009

AbstractEffects of oxygen transfer (OT) on benzaldehyde lyase (BAL) production by recombinant E. coli BL21 (DE3) pLySs were investigated at an air‐inlet rate of QO/VR = 0.5 vvm and agitation rates of N = 250, 500, 625, and 750/min; and at constant dissolved oxygen (DO) concentrations of CDO = 0.04 and 0.08 mol/m3, on a glucose based defined medium. The highest cell concentration (CX = 3.0 kg/m3) and volumetric BAL activity (A = 1095 U/cm3) were obtained at CDO = 0.08 mol/m3. KLa increased with agitation rate and decreased with CX. The highest KLa (= 0.039 s(1) was obtained at QO/VR = 0.5 vvm and N = 750/min. Damköhler number increased with decrease in agitation rate and increase in CX, while the effectiveness factor was inversely proportional to CX. The specific growth rate and the yield coefficients decreased with cultivation time and higher values were obtained in higher agitation rates. Oxygen consumption and glucose consumption for maintenance were changed proportionally and inverse proportionally with the BAL production, respectively.
Probing active‐site residues of pyranose 2‐oxidase from Trametes multicolor by semi‐rational protein design
Authors: Salaheddin Clara , Spadiut Oliver , Ludwig Roland , Tan Tien‐Chye , Divne Christina , Haltrich Dietmar , Peterbauer Clemens 
Published: April 2009

AbstractD‐Tagatose is a sweetener with low caloric and non‐glycemic characteristics. It can be produced by an enzymatic oxidation of D‐galactose specifically at C2 followed by chemical hydrogenation. Pyranose 2‐oxidase (P2Ox) from Trametes multicolor catalyzes the oxidation of many aldopyranoses to their corresponding 2‐keto derivatives. Since D‐galactose is not the preferred substrate of P2Ox, semi‐rational design was employed to improve the catalytic efficiency with this poor substrate. Saturation mutagenesis was applied on all positions in the active site of the enzyme, resulting in a library of mutants, which were screened for improved activity in a 96‐well microtiter plate format. Mutants with higher activity than wild‐type P2Ox were chosen for further kinetic investigations. Variant V546C was found to show a 2.5‐fold increase of kcat with both D‐glucose and D‐galactose when oxygen was used as electron acceptor. Because of weak substrate binding, however, kcat/KM is lower for both sugar substrates compared to wild‐type TmP2Ox. Furthermore, variants at position T169, i.e., T169S and T169N, showed an improvement of the catalytic characteristics of P2Ox with D‐galactose. Batch conversion experiments of D‐galactose to 2‐keto‐D‐galactose were performed with wild‐type TmP2O as well as with variants T169S, T169N, V546C and V546C/T169N to corroborate the kinetic properties determined by Michaelis‐Menten kinetics.