bluuebunny/crossref_metadata_2025 huggingface dataset:
Spawning pattern and batch fecundity of the European hake (Merluccius merluccius (Linnaeus, 1758)) in the western Mediterranean
Authors: Recasens Laura , Chiericoni Velia , Belcari Paola
Published: October 2008

The spawning cycle of the European hake (Merluccius merluccius, (Linnaeus, 1758)) was studied in two western Mediterranean areas, the Catalan Sea and the northern Tyrrhenian Sea, including observation of the monthly seasonal variation of the gonad maturity and the gonadosomatic index (GSI). The estimation of the maturity stages by GSI gave similar values in the two study areas: the spawning stage (IV) was easily distinguished from the other maturity stages and its range of variation showed a low overlap with stage III and no overlap with other stages. Although in both study areas active females were present during all the sampled months, the peak of reproductive activity was concentrated from February to May in the northern Tyrrhenian Sea but from August to December in the Catalan Sea, which was subjected to winter cascading events. Batch fecundity gave similar values in the Catalan and northern Tyrrhenian Seas: 204 and 202 eggs per gonad-free female gram, respectively. An asynchronous oocyte development is suggested for M. merluccius in the western Mediterranean.
First release of hatchery juveniles of the dusky grouper Epinephelus marginatus (Lowe, 1834) (Serranidae: Teleostei) at artificial reefs in the Mediterranean: results from a pilot study
Authors: La Mesa Gabriele , Longobardi Alessandro , Sacco Francesco , Marino Giovanna
Published: October 2008

A pilot experiment of stock enhancement based on the release of hatchery-reared juveniles of dusky grouper, Epinephelus marginatus, was carried out at two artificial reefs located 0.9 km offshore the south-western Sicilian coast (Central Mediterranean). The fish assemblages inhabiting the reefs were characterized using underwater visual census (UVC) surveys. Despite some differences in fish species richness, diversity and abundance, both artificial reefs provide suitable feeding resources and shelter opportunities for the settlement of dusky grouper juveniles. A total of 95 dusky grouper juveniles, which were 3 and 4 years old, were released. No stress-related effects on fish swimming or behaviour were observed during the step by step transportation to the sea-bottom at 20 m depth. After release, several groupers showed very low reactivity; freezing and schooling were the most common behaviours. The sighting rate after one month of UVC surveys was 15.7% and 20% at the two artificial reefs. No effect of fish size at release on grouper survival was observed. Some groupers were not recorded on the pyramid of release but elsewhere in the same artificial reef, which demonstrated their ability to move around the reef. The extent of dispersal of the released juveniles largely exceeded the area encompassed by the reefs, which was shown by recaptures of tagged groupers by local fishermen up to 13 km from the release site. This result provides a first insight into the potential of stock enhancement of hatchery reared dusky grouper juveniles for marine ranching and conservation purposes.
Comparison of the life cycles of two populations of the polychaete Pereinereis cf. cultrifera from the Bay of Algiers (Mediterranean Sea)
Authors: Rouabah Leila , Rouabah Abdelkader , Ferroudj Sana , Scaps Patrick
Published: October 2008

The benthic phases of the life cycles of two populations of the polychaete Pereinereis cultrifera from the Bay of Algiers were investigated using field surveys. We found no differences in the life cycle of the two populations. In the Bay of Algiers, P. cultrifera reproduces without epitokal modifications. The lifespan of the species probably does not exceed two years. The reproductive period spans most of the year but is more intense in spring from March to May when the sea-water temperature starts rising. A few mature individuals were collected at the end of summer and in winter. The oocytes take 9 to 12 months to mature and their diameter at maturity is approximately 200 µm.
XBT profilers for operational purposes: application and validation in real exercises
Authors: Machín Francisco , Emelianov Mikhail , Rodríguez Pablo , García-Ladona Emilio , Menéndez Javier , Salat Jordi
Published: October 2008

A methodology for recovering salinity from expendable bathythermograph (XBT) data is presented. The procedure exploits climatological relationships between temperature, salinity and depth to build regional characteristic curves by fitting a polynomial function that minimises both the variance of residuals and unknowns. Hence, salinity is computed and recovered as a function of temperature and depth. Empirical formula are provided to recover the salinity field from temperature-depth measurements for the Cantabrian Sea and Galician Area. The method is validated and applied in the context of two marine rescue exercises carried out in the Bay of Biscay close to the north coast of Spain and in the Finisterre region, where a series of XBT and conductivity-temperature-depth (CTD) profiles were acquired during fast samplings. The results agree reasonably well with independent data in terms of the spatial structure, with the largest errors in the upper 100 m of the ocean and at intermediate levels. The first diagnoses of the surface geostrophic velocity fields obtained through the salinity reconstruction are coherent and may help in rescue and safety operations during marine emergencies. Hence, we recommend that a technical unit should consider this kind of expandable sampling strategy with both XBT and XCTD data during marine emergencies, since it provides useful and comprehensive information rapidly with minimal interference by means of formal operations on board search and rescue ships.
Bycatch of crustacean and fish bottom trawl fisheries from southern Portugal (Algarve)
Authors: Esmeralda Costa Maria , Erzini Karim , Cerveira Borges Teresa
Published: October 2008

As part of two research projects for analysing bycatch and discards, we quantified catch composition, catch rates, bycatch and discards in two important commercial bottom trawl fisheries (crustacean and fish trawls) off the southern coast of Portugal (Algarve). Stratified sampling by onboard observers took place from February 1999 to March 2001 and data were collected from 165 tows during 52 fishing trips. Commercial target species included crustaceans: blue and red shrimp (Aristeus antennatus), deep-water rose shrimp (Parapenaeus longirostris), Norway lobster (Nephrops norvegicus); and fishes: seabreams (Diplodus spp. and Pagellus spp.), horse mackerels (Trachurus spp.) and European hake (Merluccius merluccius). The trawl fisheries are characterised by considerable amounts of bycatch: 59.5% and 80.4% of the overall total catch for crustacean and fish trawlers respectively. A total of 255 species were identified, which belonged to 15 classes of organisms (137 vertebrates, 112 invertebrates and 6 algae). Crustacean trawlers had higher bycatch biodiversity. Bony fish (45.6% and 37.8%) followed by crustaceans (14.6% and 11.5%) were the dominant bycatch components of both crustacean and fish trawlers respectively. The influence of a number of factors (e.g. depth, fishing gear, tow duration and season) on bycatch and discards is discussed.
Water, Ultrapure
Authors: Hussey Dennis F. , Foutch Gary L. , Ward M. Andy
Published: October 2008

The article contains sections titled:

1.Introduction2.Definition2.1.Ionic Purity ‐ Conductivity and Resistivity2.2.Organic Purity2.3.Particulate Purity3.Technologies used for Ultrapure Water Processing3.1.Ion Exchange Resins3.1.1.Mixed‐Bed Ion Exchangers3.1.2.Homogeneous Beds3.2.Membranes3.2.1.Reverse Osmosis3.2.2.Ultrafiltration and Nanofiltration3.2.3.Electrodeionization3.3.Adsorption ‐ Activated Carbon Beds3.4.Degasification3.5.Clarifiers and Chemical Precipitators3.6.Chemical Chlorine Removal3.7.Ultraviolet Treatment3.8.Membrane Contactors3.9.Piping Materials, Gaskets4.Analysis4.1.Ion Chromatography4.2.pH Measurement4.3.Conductivity4.4.Ion‐Selective Electrodes4.5.Determination of Total Dissolved Solids4.6.Determination of Total Organic Carbon4.7.Particle Counters4.8.Colorimetric Analyzers for Silica and Phosphate4.9.Dissolved Oxygen Electrodes4.10.Capillary Electrophoresis4.11.ORP Chlorine Analyzers4.12.Nonvolatile Residue Monitors4.13.Use of On‐line Analyzers and Manually Collected Samples5.Applications5.1.Microelectronics Industry5.2.Pharmaceutical Industry5.3.Power Industry5.3.1.Nuclear Power Plants5.3.2.Fossil Fuel‐Fired Plants5.4.Chemical Industry5.4.1.Boiler Feedwater Make‐up5.4.2.Process Water6.Future Developments
Absorption, 2. Design of Systems and Equipment
Authors: Kriebel Manfred
Published: October 2008

The article contains sections titled:

1.

Design of Absorption Systems

1.1.

Methods of Absorption

1.2.

Methods of Desorption

1.3.

Absorption and Desorption Equipment

1.4.

Columns with Mass‐Transfer Plates

1.5.

Columns with Random Packing

1.6.

Columns with Structured Packing

1.7.

Columns with Special Internals

2.

Design of Absorption Equipment

2.1.

Physical Absorption in Plate Columns

2.2.

Chemisorption in Packed Columns

2.3.

Nonisothermal Absorption

3.

Design of Desorption Equipment

3.1.

Physical Desorption in Flash Columns

3.2.

Physical Desorption in Stripper Columns

3.3.

Physical Desorption in Reboiler Columns

3.4.

Chemical Desorption in Reboiler Columns
Enzymes, 4. Non‐food Application
Authors: Herbots Ivan , Kottwitz Beatrix , Reilly Peter J. , Antrim Richard L. , Burrows Heidi , Lenting Herman B. M. , Viikari Liisa , Suurnäkki Anna , Niku‐Paavola Marja‐Leena , Pere Jaakko , Buchert Johanna
Published: October 2008

The article contains sections titled:1.Enzymes in Household Detergents2.Enzymes in Automatic Dishwashing3.Enzymes in Grain Wet‐Milling4.Enzymes in Animal Feeds5.Enzymes in Textile Production6.Enzymes in Pulp and Paper Processing
Cover Picture: Mechanical Properties of Cast Ti‐6Al‐2Sn‐4Zr‐2Mo Lattice Block Structures (Adv. Eng. Mater. 10/2008)
Authors: Li Q. , Chen E. Y. , Bice D. R. , Dunand D. C.
Published: October 2008

Lattice block structure panels, consisting of two truss plates and a truss core, produced by investment casting of the high‐temperature titanium alloy Ti‐64 (Ti‐6Al‐4V) and Ti‐6242 (Ti‐6Al‐2Sn‐4Zr‐2Mo). These low‐density panels exhibit excellent compressive stiffness, strength, ductility and energy absorption at both ambient and elevated temperature and can be used for energy‐efficient aerospace transportation systems. More details can be found in the article by Qizhen Li, Edward, Y. Chen, Douglas, R. Bice, and David C. Dunand on page 939.
Humidity‐Compensating Sensor for Volatile Organic Compounds Using Stacked Porous Silicon Photonic Crystals
Authors: Ruminski Anne M. , Moore Matthew M. , Sailor Michael J.
Published: October 2008

One‐dimensional photonic crystals constructed from multilayered stacks of porous Si are used as sensors for gas‐phase volatile organic compounds (VOCs). The ability of a double‐stack structure to provide compensation for drift due to changing relative humidity (RH) is investigated. In this approach, two separate photonic crystals (dielectric stacks) are etched into a crystalline Si substrate, one on top of the other. The top stack is chemically modified to be hydrophobic (by hydrosilylation with dodecene) and the bottom stack is made hydrophilic (by hydrosilylation with undecylenic acid). It is shown that the optical spectrum of the double‐stack structure provides an effective means to discriminate VOCs from water vapor. In this approach, shifts in the peak frequencies from both photonic crystals are measured simultaneously. Because the two stacks respond differently to water and to VOC, the effect of changing humidity can be nulled by calculating the weighted difference between the two peak frequencies. Reliable determination of the concentration of VOC vapor in nitrogen over a range of RH values (25% < RH < 75%) is demonstrated. The ability of the double‐stack structure to discriminate between water vapor and VOCs is quantified for four different VOCs: toluene, dimethyl methylphosphonate (DMMP), heptane, and ethanol.
Novel PEGylated Nanoassemblies Made of Self‐Assembled Squalenoyl Nucleoside Analogues
Authors: Bekkara‐Aounallah Fawzia , Gref Ruxandra , Othman Mohammad , Reddy L. Harivardhan , Pili Barbara , Allain Vanessa , Bourgaux Claudie , Hillaireau Hervé , Lepêtre‐Mouelhi Sinda , Desmaële Didier , Nicolas Julien , Chafi Nafa , Couvreur Patrick
Published: October 2008

This study describes a new simple method to obtain high loading of anticancer or antiviral nucleoside analogues into “stealth” poly(ethylene glycol) (PEG)‐coated nanoassemblies. These nanodevices are obtained by co‐nanoprecipitation in water of (i) squalenoyl prodrugs obtained by the bioconjugation of the natural lipid squalene with either the anticancer drug gemcitabine (Gem‐Sq) or the antiviral drug deoxycytidine (ddC‐Sq) with (ii) a PEG derivative of either cholesterol (Chol‐PEG) or squalene (Sq‐PEG). It was found that both PEG derivatives (Chol‐PEG or Sq‐PEG) were efficiently incorporated in the resulting composite nanoassemblies (CNAs), as shown by radioactivity studies, Zeta potential determination, and size measurements. Optimal compositions were defined for each PEG derivative to ensure the best stability in water and in buffer solutions. X‐ray diffraction and electron microscopy investigations revealed that depending on the structure of the squalenoyl nucleoside analogue used (Gem‐Sq or ddC‐Sq), these nanoassemblies might be toroids or cubosomes. Following PEGylation, the Gem‐Sq nanoassemblies displayed superior in vitro anticancer activity on gemcitabine‐resistant leukemia L1210 10K cells than either their non‐PEGylated counterparts or gemcitabine alone.
Multiple congenital skull fractures as a presentation of Ehlers–Danlos syndrome type VIIC
Authors: Bar‐Yosef Omer , Polak‐Charcon Sylvie , Hoffman Chen , Feldman Zeev P. , Frydman Moshe , Kuint Jacob
Published: October 2008

We describe a newborn infant with multiple congenital skull fractures and intracranial hemorrhage. He also had multiple skin folds suggesting a connective tissue abnormality. Electron microscopy of the skin biopsy showed collagen abnormalities with a “hieroglyphic appearance.” The analysis of the synthesis of collagen in the cultured dermal fibroblasts demonstrated an accumulation of procollagen I. Molecular analysis found a nonsense mutation Q225X in ADAMTS2 gene, which encodes procollagen I N‐terminal proteinase. All these findings confirmed the diagnosis of Ehlers–Danlos syndrome type VIIC (MIM 225410). Family studies suggested a founder effect in Ashkenazi Jews originating from Belarus. Prenatal diagnosis in the subsequent pregnancy reassured the parents that the fetus was an unaffected carrier. © 2008 Wiley‐Liss, Inc.
Multivariate genomewide linkage scan of neurocognitive traits and ADHD symptoms: Suggestive linkage to 3q13
Authors: Doyle Alysa E. , Ferreira Manuel A.R. , Sklar Pamela B. , Lasky‐Su Jessica , Petty Carter , Fusillo Steven J. , Seidman Larry J. , Willcutt Erik G. , Smoller Jordan W. , Purcell Shaun , Biederman Joseph , Faraone Stephen V.
Published: October 2008

Family and twin studies suggest that a range of neurocognitive traits index the inherited liability to ADHD; however, the utility of such measures as endophenotypes in molecular genetic studies remains largely untested. The current article examined whether the inclusion of neurocognitive measures in a genomewide linkage analysis of ADHD could aid in identifying QTL linked to the behavioral symptoms of the condition. Data were from an affected sibling pair linkage study of DSM‐IV ADHD conducted at Massachusetts General Hospital. The sample included 1,212 individuals from 271 families. ADHD symptoms were assessed with the K‐SADS‐E. The neurocognitive battery included Wechsler Intelligence Scales subtests, the Stroop, the Wisconsin Card Sorting Test (WCST), the Rey‐Osterreith Complex Figure, a working memory CPT, the CVLT and WRAT‐III subscales. Evidence for linkage was assessed using a simulation‐based method that combines information from univariate analyses into the equivalent of a multivariate test. After correction for multiple trait testing, a region on chromosome 3q13 showed suggestive linkage to all neurocognitive traits examined and inattention symptoms of ADHD. The second highest peak occurred on 22q12 but showed linkage to a single subscale of the WCST. In univariate analysis, this region retained criteria for suggestive linkage to this measure after correction for multiple trait testing. Our primary findings raise the possibility that one or more genes on 3q13 influence neurocognitive functions and behavioral symptoms of inattention. Overall, these data support the utility of neurocognitive traits as ADHD endophenotypes, but also highlight their limited genetic overlap with the disorder. © 2008 Wiley‐Liss, Inc.
Specific gravity as an alternative to creatinine for estimating urine concentration in captive and wild chimpanzee (Pan troglodytes) Samples
Authors: Anestis Stephanie F. , Breakey Alicia A. , Beuerlein Melanie M. , Bribiescas Richard G.
Published: October 2008

The measurement of hormones in urine has become a widely used technique in primatology. Because urine concentration varies according to fluid intake, concentration must be measured in each sample collected, and hormone values are always expressed per unit of concentration. Traditionally, creatinine has been used as a concentration index, but some studies in humans have shown that creatinine varies among populations and even within and between individuals within a population, and that it begins to degrade after just one freeze–thaw cycle. In addition, creatinine measurement is relatively time‐consuming and expensive and creates hazardous waste. In this study, we tested the hypothesis that specific gravity, or the ratio of the density of a sample to that of water, is highly correlated with creatinine measurement in urine samples collected from captive chimpanzees at the New Iberia Research Center in Louisiana and wild chimpanzees at the Ngogo study site in the Kibale National Park, Uganda. We found that specific gravity and creatinine were highly correlated in both captive (N=124) and wild (N=13) chimpanzee samples, and that specific gravity measurement was robust to actual and simulated transport conditions and repeated freeze–thaw cycles. We recommend that researchers consider specific gravity measurement as a preferable alternative to creatinine measurement in their studies of primate endocrinology. Am. J. Primatol. 71:130–135, 2009. © 2008 Wiley‐Liss, Inc.
Studies on electro‐optical properties of polymer matrix/LC/SiO2 nanoparticles composites
Authors: Li Wenbo , Zhu Mengjun , Ding Xiaokang , Li Bofu , Huang Wei , Cao Hui , Yang Zhou , Yang Huai
Published: October 2008

Polymer‐dispersed liquid crystal (PDLC) films were prepared by ultraviolet light‐induced polymerization of photopolymerizable monomers in nematic liquid crystal (LC)/monomers/SiO2 nanoparticles composites, and the effect of SiO2 nanoparticles on the electro‐optical properties of PDLC films was studied. The observed effect showed that by the adjustment of the SiO2 nanoparticles content, the refractive index ratio of the LC and polymer could be modulated, and the electro‐optical properties of the polymer matrix/LC/SiO2 nanoparticles composites could be optimized. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effects of monomer structure on the morphology of polymer network and the electro‐optical property of reverse‐mode polymer‐stabilized cholesteric texture
Authors: Yin Yuhai , Li Wenbo , Cao Hui , Guo Jinbao , Li Bofu , He Simin , Ouyang Canbin , Cao Ming , Huang Hua , Yang Huai
Published: October 2008

The morphologies of the polymer networks in the polymer network/LC composite of reverse‐mode polymer‐stabilized cholesteric texture (PSCT) films was observed. The polymer network/LC composite was prepared from photopolymerization of the acrylate monomers, which had rod‐like rigid cores in monomer/LC mixture. The effects of the structure of the acrylate monomers on the morphology of polymer network were studied. The acrylate monomer without flexible pacers between the acrylate functional groups and the rigid core formed rice‐grain‐like polymer network with poor orientation. The acrylate monomer with flexible pacers formed fiber‐like polymer network with better orientation. Meanwhile, the effects of morphology of polymer network on the electro‐optical property of reverse‐mode PSCT films were also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Surface modification of cellulose filter paper by glycidyl methacrylate grafting for biomolecule immobilization: Influence of grafting parameters and urease immobilization
Authors: Tyagi Charu , Tomar Lomas Kumar , Singh Harpal
Published: October 2008

Graft copolymerization of glycidyl methacrylate (GMA) onto cellulose filter paper (CFP) was carried out by a free‐radical initiating process using ceric ammonium nitrate (CAN) as an initiator. Optimum conditions pertaining to different grafting percentages were evaluated as a function of monomer and initiator concentrations, polymerization time and temperature. CFP with various graft levels of GMA was characterized by fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis (TGA). Surface morphology of ungrafted and grafted CFP was evaluated by scanning electron microscopy (SEM). Attenuated total reflectance (ATR)‐FTIR spectral analysis provided the evidence of grafting of GMA onto CFP. The maximum grafting of 102% was achieved by using 4 × 10−3 molL−1 CAN and 5% of GMA (w/v) monomer at 60°C in 25 min. The CFP‐g‐GMA surfaces with different graft levels were evaluated as a support for immobilization of biomolecules. Urease was selected as the model enzyme to be covalently coupled through the surface epoxy groups of the CFP‐g‐GMA discs. Immobilized discs were further studied for urea estimation and their reusability. Although the highest degree of urease immobilization was observed at 100% (162‐μg urease/disc) graft level, the urease immobilized on discs with 70% (105‐μg urease/disc) graft level gave the maximum activity of the enzyme. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of polystyrene/poly(methyl methacrylate) core‐shell composite particles by suspension‐emulsion combined polymerization
Authors: Zhenqian Zhang , Yongzhong Bao , Zhiming Huang , Zhixue Weng
Published: October 2008

Suspension‐emulsion combined polymerization process, in which methyl methacrylate (MMA) emulsion polymerization constituents (EPC) were drop wise added to styrene (St) suspension polymerization system, was applied to prepare polystyrene/poly(methyl methacrylate) (PS/PMMA) composite particles. The influences of the feeding condition and the composition of EPC on the particle feature of the resulting composite polymer particles were investigated. It was found that PS/PMMA core‐shell composite particles with a narrow particle size distribution and a great size would be formed when the EPC was added at the viscous energy dominated particle formation stage of St suspension polymerization with a suitable feeding rate, whereas St‐MMA copolymer particles or PS/PMMA composite particles with imperfect core‐shell structure would be formed when the EPC was added at the earlier or later stage of St suspension polymerization, respectively. It was also showed that the EPC composition affected the composite particles formation process. The individual latex particles would exist in the final product when the concentrations of MMA monomer, sodium dodecyl sulfate emulsifier, and potassium persulfate initiator were great in the EPC. Considering the feature of St suspension polymerization and the morphology of PS/PMMA composite particles, the formation mechanism of PS/PMMA particles with core‐shell structure was proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polymethylsilsesquioxane and hydroxyl‐terminated polydimethylsiloxane composite: Vapor incubation before thermal curing
Authors: Li Yanfang , Yang Shuguang , Liu Haiyun , Li Xiaofeng , Dai Zhen , Zhao Ning , Xu Jian
Published: October 2008

A composite film of polymethylsilsesquioxane (PMSQ) and hydroxyl‐terminated polydimethylsiloxane (PDMS) was prepared by incubating PMSQ prepolymer and PDMS solution in a vapor environment before thermal curing. Vapor incubation has a significant influence on the morphology and properties of the cured composite, and the vapor incubation was conducted under three different conditions, i.e., acidic, neutral, and basic. In the acidic vapor of a pH rather lower than the isoelectric point (IEP) of the silanol, the reaction between PMSQ and PDMS through silanol condensation was promoted by the protonation of silanol. PDMS rubber particles with a domain size of about 100 nm were formed in PMSQ matrix, and the flexible modulus of the film was improved. While, the morphology of the resultant film was smooth and uniform after incubation in a neutral water vapor. The basic vapor facilitated the gelation of composite due to high pH inducing more rapid silanol condensation in PMSQ than phase separation. Moreover, excellent optical transparency, insulation, and thermal stability of the composite were also retained after the PDMS incorporation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Long‐term investigation on hydrolytic degradation and morphology of poly(ethylene glycol terephthalate)‐b‐poly(butylene terephthalate) copolymer films
Authors: Zhang Aiying , Feng Zengguo , Xie Zhiguo
Published: October 2008

Poly(ethylene glycol terephthalate)‐b‐Poly(butylene terephthalate) copolymer (PEGT‐b‐PBT) films with different copolymer compositions were incubated in phosphate buffered saline under pH 7.4 at 37°C to study hydrolytic degradation and morphology up to 300 days. With the fall of intrinsic viscosity and mass of degraded films, SEM micrographs show that a set of particular and highly interconnected porous morphologies closely related to the content of PBT hard segments in copolymer is developed. Moreover, the variation in PBT crystallinity for copolymer films with weight ratio of 70/30 fluctuates with the development of degradation profiles, and PEGT content for copolymer films with weight ratio of 80/20 and 70/30 gradually decreases. The hydrolytic experiments demonstrate that the degradation of PEGT‐b‐PBT copolymer results from the cleavage of ester bonds between hydrophilic PEG and terephthalate. At the beginning period of degradation, PEGT‐b‐PBT copolymer films follow a typical mechanism of bulk degradation, and then undergo both bulk degradation and surface erosion, all of which finally generate the particular porous morphologies for copolymer films. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Controlling degradation and physical properties of chemical sand fixing agent‐poly(aspartic acid) by crosslinking density and composites
Authors: Yang Jun , Wang Fang , Tan Tianwei
Published: October 2008

Poly(aspartic acid) (PASP) hydrogel crosslinked with 1,6‐ hexamethylene diamine was applied as sand fixing agent. The effect of crosslinking density of sand fixing agent on sand fixing property was studied. The relations between the degradation time and crosslinking density, sand fixing property, molecular weight, and mass loss were measured. It was found that the sand fixing property relied on the PASP crosslinking density and degradation time. The crust attained the maximal mechanical strength when the PASP crosslinking agent concentration was 0.0325 mol/L and the PASP hydrogel mass loss was 97.9% after 18 days. The composites added into PASP could increase mechanical property and prolong the degradation time when compared with the control. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of poly(ethylene succinate) and its copolyesters containing minor amounts of butylene succinate
Authors: Chen Chi‐He , Lu Hsin‐Ying , Chen Ming , Peng Jyun‐Siang , Tsai Chia‐Jung , Yang Chao‐Sen
Published: October 2008

Poly(ethylene succinate) (PES) and its copolyesters that contain 7, 10, or 48 mol % butylene succinate (BS) were synthesized through a direct polycondensation reaction with titanium tetraisopropoxide as the catalyst. Measurements of intrinsic viscosity (1.08–1.27 dL/g) proved the success of the preparation of polyesters with high molecular weights. The compositions and the sequence distributions of the copolyesters were determined from 1H and 13C NMR spectra. The distributions of ethylene succinate and BS units were found to be random. Their thermal properties were elucidated using a differential scanning calorimeter (DSC) and a thermogravimetric analyzer. No significant difference exists among the thermal stabilities of these polyesters. All of the copolymers exhibit a single glass transition temperature. Wide‐angle X‐ray diffractograms (WAXD) were obtained from polyesters that were crystallized isothermally. The DSC thermograms and WAXD patterns indicate that the incorporation of BS units into PES significantly inhibits the crystallization behavior of PES. The heat of fusion of ideal PES crystals is 163 J/g, as determined by the depression of the melting point of PES crystals in acetophenone. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Hydrodynamic properties of aqueous dextran solutions
Authors: Xu Xuelin , Li Hangquan , Zhang Zhengdong , Qi Xin
Published: October 2008

The hydrodynamic performance of aqueous dextran solutions, including the rheological and thixotropic properties, were investigated. Three kinds of dextrans with different molecular weights were employed to examine the effects of the molecular weight, concentration, temperature, and so forth on the hydrodynamic properties of aqueous dextran solutions. The results showed that an aqueous solution of a dextran with a high molecular weight of 5.223 × 105 at a high concentration of 30 wt % had pseudoplastic properties, in contrast to the conclusions of other researchers finding that aqueous dextran solutions were Newtonian liquids. The viscosity of the aqueous dextran solutions decreased with temperature, and the activation energy was calculated to be 16,849.2 J/mol with a 10 wt % dextran (weight‐average molecular weight = 5.223 × 105) solution. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Investigation of styrene‐assisted free‐radical grafting of glycidyl methacrylate onto high‐density polyethylene using response surface method
Authors: Saeb M. R. , Garmabi H.
Published: October 2008

In this study, the free‐radical grafting of glycidyl methacrylate (GMA) onto high‐density polyethylene (HDPE) in the presence of styrene, as a comonomer, is investigated using a Brabender internal mixer. To optimize grafting level of GMA onto HDPE, response surface method (RSM) was exploited. Using RSM method of experimental design, it was possible to investigate the individual effects of various variables including dicumyl peroxide (DCP) concentration, GMA content, as well as reaction time, and their interactions on grafting efficiency. The fitted quadratic model obtained from statistical analysis is expressed by an approximating function to investigate the final torque as a responding variable over the experimental range of the independent variables. The grafting yield of GMA onto HDPE for the prepared samples was determined using titration/back‐titration technique and Fourier transform infrared spectroscopy (FTIR). According to the torque–time diagrams, increasing the DCP content led to an increase in GMA grafting yield. Also, it was found that the reaction time imparts minor effect on the final processing torque, and there exists an interaction between DCP and GMA content. The results of melt flow index (MFI) test showed that increasing the reaction time at constant DCP and GMA content enhances the MFI values of the samples, due to the more probability of chain scission phenomenon. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Development of antimicrobial membranes via the surface tethering of chitosan
Authors: Nigmatullin R. , Konovalova V. , Pobigay G.
Published: October 2008

To render the surface of ultrafiltration membranes biocidal, cellulose membranes were modified with chitosan, a naturally occurring polycationic biocide. Through the use of chitosans of different molecular weights and membranes with different pore sizes, the alteration of the morphological structure of tethered chitosan layers was achieved. The importance of such structural differences in the antimicrobial activity of the prepared membranes against gram‐positive Staphylococcus aureus and gram‐negative Escherichia coli was studied. The antimicrobial efficiency improved with the use of chitosans with higher molecular weights and membranes with smaller pore sizes. This suggested that the surface location of the grafted chitosan chains was more preferential for a higher antimicrobial activity of the surface. Membranes modified with chitosan showed higher antimicrobial efficiency against gram‐positive S. aureus than against gram‐negative E. coli. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Bulk prepolymerization of styrene in the presence of polybutadiene: Determination of grafting efficiency by size exclusion chromatography combined with a new extended model
Authors: Casis Natalia , Estenoz Diana A. , Vega Jorge R. , Meira Gregorio R.
Published: October 2008

The bulk prepolymerization of styrene in the presence of polybutadiene for the production of high‐impact polystyrene is analyzed and compared with an equivalent solution reaction described by Estenoz et al. in 1999. The heterogeneous model reported by Casis et al. in 2006 is extended to predict the bivariate distributions of the graft copolymer topologies; each topology is characterized by the number of trifunctional branching points per molecule. The developed model assumes polymerization in two phases and requires the adjustment of a single kinetic parameter. Grafting efficiencies determined by solvent extraction/gravimetry are compared with determinations obtained by the deconvolution of size exclusion chromatograms of the total polymer. The chromatographic technique is fast and simple, but it requires a representative polymerization/fractionation model. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Using modulated‐temperature differential scanning calorimetry to study interphases in blends of styrene–butadiene and polybutadiene rubbers filled with a silanized silica nanofiller
Authors: Ostad‐Movahed S. , Ansarifar A. , Song M.
Published: October 2008

Polybutadiene and styrene–butadiene rubber compounds containing a high loading of a precipitated silica nanofiller were prepared. The silica surfaces were pretreated with bis(3‐triethoxysilylpropyl) tetrasulfide to prevent the silica from interfering with the reaction mechanism of sulfur cure in the rubber. The rubber compounds were mixed together for different times and at different temperatures to produce styrene–butadiene rubber/polybutadiene rubber blends. The mass fraction and composition of the interphase in the blends were subsequently determined with modulated‐temperature differential scanning calorimetry. At 60–65°C, the mass fraction of the interphase in the blend increased after the rubbers were mixed together for 10 min, and then it decreased significantly when the mixing time was increased to 20 min. When the two rubbers were mixed together for 7 min at 60–105°C, the mass fraction of the interphase in the blend increased slightly because of a higher mixing temperature. The composition of the interphase in the blend also changed with the mixing time and mixing temperature. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Application of the group contribution approach to Nafion swelling
Authors: Randová Alena , Bartovská Lidmila , Hovorka Štěpán , Poloncarzová Magda , Kolská Zdeňka , Izák Pavel
Published: October 2008

The anisotropic swelling of Nafion 112 membrane in pure organic liquids was monitored by an optical method. The findings were used as a basis for application of the group contribution method to the relative expansion in equilibrium. From a total of 38 organic liquids under study, 26 were selected as an evaluational set from which the group and structural group contributions were assigned. The remaining 12 compounds were used as the testing set. Value of ±1.5% in relative expansions was determined to be the experimental error. Maximum differences between the experimental and calculated relative expansions in both sets did not exceed the value of ±3%. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Structure and properties of soy protein films plasticized with hydroxyamine
Authors: Tian Huafeng , Liu Dagang , Zhang Lina
Published: October 2008

Two kinds of transparent films of soy protein were successfully prepared by plasticizing with diethanolamine (DEA) and triethanolamin (TEA). The films were hot pressed at 140°C and 20 MPa, and characterized with Fourier transform infrared spectroscopy, scanning electron microscope, ultraviolet–visible spectrometer, differential scanning calorimetry (DSC), thermogravimetric analysis, and tensile testing. The results indicated that films with triethanolamine plasticizers possessed better optical transmittance (more than 80% at 800 nm) than those with diethanolamine and glycerol. All of the sheets exhibited only one Tg in DSC curves. Moreover, the soy protein plastics with TEA had higher thermal stability and mechanical properties, as well as lower water uptake than those with DEA and glycerol, as a result of the strong interaction between TEA and protein molecules. The soy protein materials will be promising for the application in the fields of package and container, substituting for the nongreen polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of brush copolymers based on methoxy poly(ethylene glycol) and poly(ε‐caprolactone)
Authors: Bajgai Madhab Prasad , Aryal Santosh , Parajuli Daman Chandra , Khil Myung‐Seob , Lee Duck Rae , Kim Hak Yong
Published: October 2008

Brush copolymers composed of methoxy poly(ethylene glycol) (MPEG) and poly(ε‐caprolactone) (PCL) have been synthesized by the ring‐opening polymerization of ε‐caprolactone initiated by hydroxyl function of thermally esterified MPEG‐citrate in presence of stannous octoate. Citric acid (CA) acts as spacer between brush‐like MPEG and the long chain of PCL. Existence of hydrophobic domains as cores of the micelles were characterized by 1H NMR spectroscopy and further confirmed with fluorescence technique using pyrene as a probe. Critical micelle concentration (CMC) of the synthesized copolymer decreased from 0.019 to 0.0031 mg/mL on increasing the fraction of PCL. Along with the physicochemical study, the brush copolymers were explored for the preparation of nanoparticles by nanoprecipitation technique. The morphology and geometry of micelles were investigated by using DLS, AFM, and TEM. Hydrodyanamic dimensions of micelles were around 118 and 178 nm with the core size of 8–10 nm, which further aggregated to form secondary micelle of 60–90 nm. Such assembled polymeric micelles with its flexible dendritic MPEG corona could hold a promise for the immobilization (encapsulation) of hydrophobic drugs and subsequently promote sustained release so that it can be a good vehicle for anti‐cancer drug deliverance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
High yield synthesis of diverse well‐defined end‐functionalized polymers by combination of anionic polymerization and “click” chemistry
Authors: Ho Chun‐Chih , Dai Chi‐An , Su Wei‐Fang
Published: October 2008

Well‐defined poly(methyl methacrylate) (Mn = 3630 g mol−1, PDI = 1.06) with a primary benzylic bromide prepared using anionic polymerization was successfully transformed into diverse end‐functionalities (ω‐carboxyl, ω‐hydroxy, ω‐methyl‐vinyl, ω‐trimethylsilane, and ω‐glycidyl‐ether) via “click” reaction. The bromine end‐terminated poly(methyl methacrylate) was first substituted by an azide function and sequentially was reacted with various functional alkynes (propiolic acid, propargyl alcohol, 2‐methyl‐1‐buten‐3‐yne, propargyl trimethylsilane, and propargyl glycidylether). In all the cases, 1H‐NMR, 13C NMR, FT‐IR, and GPC measurements show qualitative and quantitative transformation of the chain‐end poly(methyl methacrylate) into the desired functionalities with high conversion (above 99%). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Novel biodegradable amphiphilic poly(ε‐caprolactone)/poly(N‐vinylpyrrolidone) blends via successive in situ polymerizations
Authors: Xing Zhimin , Xie Tingxiu , Yang Guisheng
Published: October 2008

In this study, biodegradable blends of poly(ε‐caprolactone) (PCL) and poly(N‐vinylpyrrolidone) (PVP) were prepared by a new strategy in the following steps: (1) free radical polymerization of N‐vinyl‐2‐pyrrolidone (NVP) in ε‐caprolactone (CL); (2) ring‐opening polymerization of ε‐caprolactone in the presence of PVP to obtain the target blends. The structure of the blends was confirmed by FTIR and 1H NMR, and the molecular weight of PCL and PVP were determined by GPC. SEM study revealed that this polymerization method could decrease the disperse phase size and improve the interphase when compared with solution‐blending method. The phase inversion occurred when PVP content was 15–20 wt %. Subsequently, the PCL sphere dispersed in PVP matrix and its size decreased with the increase of PVP content. The contact angle results showed that PVP has a profound effect on hydrophilic properties of PCL/PVP blends. PCL/PVP blends are believed to be promising for drug delivery, cell therapy, and other biomedical applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Comparison of micelles formed by amphiphilic poly(ethylene glycol)‐b‐poly(trimethylene carbonate) star block copolymers
Authors: Kim Byung Soo , Oh Jae Min , Cho Jae Song , Lee Sang Hyo , Lee Bong , Khang Gilson , Lee Hai Bang , Kim Moon Suk
Published: October 2008

In this article, we describe the synthesis and solution properties of PEG‐b‐PTMC star block copolymers via ring‐opening polymerization (ROP) of trimethylene carbonate (TMC) monomer initiated at the hydroxyl end group of the core PEG using HCl Et2O as a monomer activator. The ROP of TMC was performed to synthesize PEG‐b‐PTMC star block copolymers with one, two, four, and eight arms. The PEG‐b‐PTMC star block copolymers with same ratio of between hydrophobic PTMC and hydrophilic PEG segments were obtained in quantitative yield and exhibited monomodal GPC curves. The amphiphilic PEG‐b‐PTMC star block copolymers formed spherical micelles with a core–shell structure in an aqueous phase. The mean hydrodynamic diameters of the micelles increased from 17 to 194 nm with increasing arm number. As arm number increased, the critical micelle concentration (CMC) of the PEG‐b‐PTMC star block copolymers increased from 3.1 × 10−3 to 21.1 × 10−3 mg/mL but the partition equilibrium constant, which is an indicator of the hydrophobicity of the micelles of the PEG‐b‐PTMC star block copolymers in aqueous media, decreased from 4.44 × 104 to 1.34 × 104. In conclusion, we confirmed that the PEG‐b‐PTMC star block copolymers form micelles and, hence, may be potential hydrophobic drug delivery vehicles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polypropylene cellulose‐based composites: The effect of bagasse reinforcement and polybutadiene isocyanate treatment on the mechanical properties
Authors: Ashori Alireza , Nourbakhsh Amir
Published: October 2008

Using bagasse fiber as the reinforcing filler and polypropylene as the thermoplastic matrix polymer, a reinforced composite was prepared, and its mechanical properties examined as a function of the amount of compatibilizing agents used. In the sample preparation, four levels of fiber loading (10, 20, 30, and 40 wt %), three levels of polybutadiene isocyanate (PBNCO) content (0, 2, and 4 wt %) and two levels of maleated polypropylenes (MAPP) content (0 and 3 wt %) as compatibilizing agents were used. The tensile properties of the composites improved as the fiber loading and the compatibilizing agents increased, but the impact strength was significantly decreased. The mechanical study revealed that the positive effect of compatibilizing agents on interfacial bonding. The composites treated with PBNCO showed superior tensile and impact properties than those without treatment. The findings indicated that bagasse as agro‐waste material is a valuable renewable natural resource for composite production and could be utilized as a substitute for wood in composite industries. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Magnetic and optical properties of poly(vinylidene difluoride)/Fe3O4 nanocomposite prepared by coprecipitation approach
Authors: Xu Chunhua , Ouyang Chunfa , Jia Runping , Li Yongsheng , Wang Xia
Published: October 2008

Poly(vinylidene difluoride) (PVDF)/Fe3O4 magnetic nanocomposite was prepared by a simple coprecipitation method, and was characterized by scanning electron microscope (SEM), X‐ray diffraction (XRD), vibrating sample magnetometer (VSM), and ultraviolet visible spectroscopy (UV‐Vis). The SEM images showed that Fe3O4 nanoparticles were dispersed in the PVDF matrix as some aggregates with the sizes of 50 nm–2 μm, and the XRD curves showed the incorporation of the Fe3O4 nanoparticles in PVDF matrices and the decrease of the crystallinity of the PVDF. VSM results showed that the saturation magnetization (Ms) and remnant magnetization (Mr) of the PVDF/Fe3O4 nanocomposite increased with the increase of the Fe3O4 content, and that Ms and Mr along the parallel direction were higher than those along the perpendicular direction at the same Fe3O4 content. The coercive force (Hc) of the nanocomposite was independent of the Fe3O4 content and approximately equal along the parallel and perpendicular direction at the same Fe3O4 content. The optical band gap (Eg) of the PVDF/Fe3O4 nanocomposite was influenced by the Fe3O4 content, and decreased by 0.75 eV compared with that of pure PVDF when the Fe3O4 content was 3 wt %. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Design and Synthesis of Novel Benzopyran‐2‐one Derivatives of Expected Antimicrobial Activity through DNA Gyrase‐B Inhibition
Authors: Hassan Ghaneya S. , Farag Nahla A. , Hegazy Gehan H. , Arafa Reem K.
Published: October 2008

In an attempt to find a new class of antibacterial agents, we have synthesized thirty new coumarin (2H‐benzopyran‐2‐one) analogues. These derivatives include substituted azetidin‐2‐ones (β‐lactam) 3a–f, pyrrolidin‐2‐ones 4a–f, 2H‐1,3,4‐oxadiazoles 5a–f, and thiazolidin‐4‐ones 6a–f attached to 4‐phenyl‐2H‐benzopyran‐2‐one through an oxyacetamido or an oxymethyl bridge. The target compounds were synthesized starting from 2‐oxo‐4‐phenyl‐2H‐benzo[b]pyran‐7‐yl‐oxyacetic acid hydrazides 2a–f. The new compounds were evaluated as DNA gyrase‐B inhibitors through molecular modeling and docking techniques using the Molsoft ICM 3.4‐8C program. The synthesized compounds were also screened for antibacterial activity against four different species of Gram‐positive and Gram‐negative bacteria; as well as screening against C. albicans for antifungal activity. The molecular modeling data were in accordance with the antimicrobial screening results.
Synthesis of Novel Substituted 7‐(Benzylideneamino)‐4‐Methyl‐2H‐Chromen‐2‐one Derivatives as Anti‐inflammatory and Analgesic Agents
Authors: Ronad Pradeepkumar , Dharbamalla Satyanarayana , Hunshal Rajesh , Maddi Veeresh
Published: October 2008

A series of novel Schiff' base‐containing a 7‐amino‐4‐methylcoumarin moiety have been synthesized III a–l, characterized by spectroscopic data and studied for their anti‐inflammatory and analgesic activity. The results of the anti‐inflammatory and analgesic activity evaluation of 7‐(substituted benzylideneamino)‐4‐methyl‐2H‐chromen‐2‐one derivatives III a–l proved to be comparable or more potent with respect to the reference drugs. In particular, compounds 7‐(4‐chlorobenzylideneamino)‐4‐methyl‐2H‐chromen‐2‐one III f, 7‐(2,4‐dichlorobenzylideneamino)‐4‐methyl‐2H‐chromen‐2‐one III g and 7‐(4‐bromobenzylideneamino)‐4‐methyl‐2H‐chromen‐2‐one III h exhibited potent anti‐inflammatory and analgesic activity.