bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultraviolet‐B Radiation Effects on the Structure and Function of Lower Trophic Levels of the Marine Planktonic Food Web
Authors: Ferreyra Gustavo A. , Mostajir Behzad , Schloss Irene R. , Chatila Khaled , Ferrario Martha E. , Sargian Peggy , Roy Suzanne , Prod'homme Johann , Demers Serge 
Published: May 2006

ABSTRACTThe impact of UV‐B radiation (UVBR; 280–320 nm) on lower levels of a natural plankton assemblage (bacteria, phytoplankton and microzooplankton) from the St. Lawrence Estuary was studied during 9 days using several immersed outdoor mesocosms. Two exposure treatments were used in triplicate mesocosms: natural UVBR (N treatment, considered as the control treatment) and lamp‐enhanced UVBR (H treatment, simulating 60% depletion of the ozone layer). A phytoplankton bloom developed after day 3, but no significant differences were found between treatments during the entire experiment for phytoplankton biomass (chlorophyllaand cell carbon) nor for phytoplankton cell abundances from flow cytometry and optical microscopy of three phytoplankton size classes (picoplankton, nanoplankton and microplankton). In contrast, bacterial abundances showed significantly higher values in the H treatment, attributed to a decrease in predation pressure due to a dramatic reduction in ciliate biomass (∼ 70–80%) in the H treatment relative to the N treatment. The most abundant ciliate species wereStrombidiniumsp.,Prorodon ovumandTintinnopsissp.; all showed significantly lower abundances under the H treatment.P. ovumwas the less‐affected species (50% reduction in the H treatment compared with that of the N control), contrasting with ∼90% for the other ones. Total specific phytoplanktonic and bacterial production were not affected by enhanced UVBR. However, both the ratio of primary to bacterial biomass and production decreased markedly under the H treatment. In contrast, the ratio of phytoplankton to bacterial plus ciliate carbon biomass showed an opposite trend than the previous results, with higher values in the H treatment at the end of the experiment. These results are explained by the changes in the ciliate biomass and suggest that UVBR can alter the structure of the lower levels of the planktonic community by selectively affecting key species. On the other hand, linearity between particulate organic carbon (POC) and estimated planktonic carbon was lost during the postbloom period in both treatments. On the basis of previous studies, our results can be attributed to the aggregation of carbon released by cells to the water column in the form of transparent exopolymer particles (TEPs) under nutrient limiting conditions. Unexpectedly, POC during such a period was higher in the H treatment than in controls. We hypothesize a decrease in the ingestion of TEPs by ciliates, in coincidence with increased DOC release by phytoplankton cells under enhanced UVBR. The consequences of such results for the carbon cycle in the ocean are discussed.
Statins reduce human blood–brain barrier permeability and restrict leukocyte migration: Relevance to multiple sclerosis
Authors: Ifergan Igal , Wosik Karolina , Cayrol Romain , Kébir Hania , Auger Chantale , Bernard Monique , Bouthillier Alain , Moumdjian Robert , Duquette Pierre , Prat Alexandre 
Published: May 2006

AbstractObjectiveDysregulation of the blood–brain barrier (BBB) and transendothelial migration of immune cells are among the earliest central nervous system changes partaking in lesion formation in both multiple sclerosis (MS) and its early clinical form, the clinically isolated syndrome. Evidence for the anti‐inflammatory effects of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase inhibitors within the central nervous system arose from studies demonstrating that statins improve clinical signs in the animal model of MS and reduce the number of gadolinium‐enhancing lesions in MS.MethodsWe sought to describe the impact of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase inhibitor treatment on the physiology and immunology of human BBB‐derived endothelial cells (ECs).ResultsWe demonstrate that lovastatin and simvastatin induce a 50 to 60% reduction in the diffusion rates of bovine serum albumin and [14C]‐sucrose across human BBB‐ECs in vitro through abrogation of isoprenylation processes, but independent of the expression of the tight junction molecules occludin, VE‐cadherin, JAM‐1, zonula occluden‐1, and zonula occluden‐2. Simvastatin and lovastatin were equipotent in reducing BBB permeability in vitro, with median effective concentration (EC50) of 9.5 × 10−8 and 1.0 × 10−7M, respectively. We further demonstrate that lovastatin and simvastatin treatment of BBB‐ECs significantly restricts the migration of clinically isolated syndrome–derived and MS‐derived monocytes and lymphocytes across the human BBB in vitro, through a specific reduction in the secretion of the chemokines monocyte chemotactic protein‐1/CCL2 and interferon‐γ–inducible protein‐10/CXCL10 by BBB‐ECs.InterpretationOur data parallel the previously reported magnetic resonance imaging–based radiological findings and suggest an effect of statins that could be beneficial in early MS, restricting the diffusion of molecular tracers and the migration of immune cells across the human BBB. Ann Neurol 2006
Modeling of polymer/clay nanocomposite formation
Authors: Kim Younghoon , White James L. 
Published: May 2006

AbstractA statistical thermodynamic modeling of the formation of polymer/clay intercalation and nanocomposites was developed. The key factor in determining intercalation was an exothermic heat of mixing between polymer chains and the organically modified silicate surface. This was found to agree with previous experimental results in the literature including halogenated polymers and acrylonitrile copolymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1657–1663, 2006
Preparation of biodegradable crosslinking agents and application in PVP hydrogel
Authors: Jiao Yanpeng , Liu Zonghua , Ding Shan , Li Lihua , Zhou Changren 
Published: May 2006

AbstractFirstly, biodegradable crosslinking agents (BCA) were synthesized by ring‐opening polymerization reaction of lactide, four kinds of which with different molecular weights were got by means of changing the ratio of DL‐lactide(LA) and glycerol(GL). Then a series of poly(N‐vinyl pyrrolidone) (PVP) hydrogels were prepared successfully by radical polymerization of BCA and N‐vinyl pyrrolidone(NVP). Both the ratio of NVP/BCA and the molecular weight of BCA were used to control the performance of PVP hydrogels, which were measured in terms of the ratio of swelling, contact angle, mechanical properties, and biodegradability in vitro. This study showed that increasing both the ratio of NVP/BCA and the molecular weight of BCA resulted in a low crosslinking density of the hydrogels. The crosslinking density played an important role in determining the properties of biodegradable PVP hydrogels. Both the ratio of NVP/BCA and the molecular weight of BCA contributed to high ratio of swelling. A smaller amount of crosslinking agent caused a lower contact angle, while the molecular weight of BCA had little effect on it. In terms of mechanics of hydrogels on both dry and wet conditions, tensile modulus decreased along with decreasing BCA, while the extension at break increased at the beginning and decreased at the end. In the end, measured by mass loss, biodegradability in vitro of hydrogels had two stages: an initial stage with approximately constant loss of mass (stage 1) followed by a stage with rapid mass loss (stage 2). Both increased content and molecular weight of BCA improved the degradation rate of the hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1515–1521, 2006
Waste polyvinyl chloride‐modified bitumen
Authors: Abdel‐Goad Mahmoud A‐Halim 
Published: May 2006

AbstractPolyvinyl chloride (PVC) pipe wastes have been employed as a soft filler up to a level of 11 wt % in making bituminous products for paving applications. The PVC wastes were homogenously mixed with bitumen in the molten state. The viscoelastic properties of the bitumen blends such as storage modulus, loss modulus, and dynamic viscosity were studied and compared with those of neat bitumen. These properties were studied using an ARES‐Rheometer (Rheometric Scientific, Co.) under nitrogen atmosphere. The results indicate that the incorporation of the waste PVC into bitumen enhances the dynamic mechanical moduli and viscosity of the bitumen. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1501–1505, 2006
Studies of poly(8‐hydroxy‐4‐azoquinolinephenol‐formaldehyde) and its metal complexes
Authors: Vijayalakshmi S. , Subramanian S. , Rajagopan S. , Kaliyappan T. 
Published: May 2006

AbstractPoly(8‐hydroxy‐4‐azoquinolinephenol‐formaldehyde) resin (8H4AQPF) was prepared by condensing 8‐hydroxy 4‐azoquinoline phenol with formaldehyde (1 : 1 mol ratio) in the presence of oxalic acid. Polychelates were obtained when the DMF solution of poly(8H4AQPF) containing a few drops of ammonia was treated with the aqueous solution of Cu(II) and Ni(II) ions. The polymeric resin and polymer–metal complexes were characterized with elemental analysis and spectral studies. The elemental analysis of the polymer–metal complexes suggested that the metal‐to‐ligand ratio was 1 : 2. The IR spectral data of the polychelates indicated that the metals were coordinated through the nitrogen and oxygen of the phenolic OH group. Diffuse reflectance spectra, electron paramagnetic resonance, and magnetic moment studies revealed that the polymer–metal complexes of the Cu(II) complexes were square planar and those of the Ni(II) complexes were octahedral. X‐ray diffraction studies revealed that the polymer metal complexes were crystalline. The thermal properties of the polymer and polymer–metal complexes were also examined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1506–1510, 2006
Synthesis of poly(ester sulfoimide) from dichlorocarbonylimide of disaccharindicarboxylic acid and aromatic diols
Authors: Aslanov T. A. , Salakhov M. S. , Efendiev A. A. 
Published: May 2006

AbstractA new chlorocarbonylimide of disaccharindicarboxylic acid was synthesized by condensation of imides of saccharin‐6‐carboxylic acid with alkyl‐ and alkylaryl bishalogenides. Poly(ester sulfoimide), soluble in organic solvents, was synthesized by polycondensation of chlorocarbonylimide with bisphenol. DTA and TGA investigations have shown that poly(ester sulfoimide)s were stable at temperatures up to 300°C–345°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1687–1691, 2006
Structure and properties of polymer–wood composites based on an aliphatic copolyamide and secondary polyethylenes
Authors: Mamunya Y. , Zanoaga M. , Myshak V. , Tanasa F. , Lebedev E. , Grigoras C. , Semynog V. 
Published: May 2006

AbstractComposite materials based on an aliphatic copolyamide and a secondary polyethylene, as thermoplastic matrices, and wood chips as filler were obtained and characterized. The influence of different factors (polymeric matrix type, fractional composition and geometrical characteristics of wood filler, processing parameters and ratio polymer/wood) on the properties of polymer–wood composites (PWCs) was studied. It was demonstrated that the packing factor F has an essential influence on the properties of PWCs: increasing F values determines an improvement in mechanical properties of these materials. Mechanical properties, thermal behaviour, morphological and diffusion characteristics of the analyzed composites were evaluated through specific methods and reported herein. Morphological and DSC data confirmed the presence of strong interface interactions between polymer and wood. The diffusion characteristics of PWCs showed that the diffusion coefficient D essentially depends on filler content in composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1700–1710, 2006
Surface‐modified polysulfone membranes: Aqueous phase oxidation via persulfate radical
Authors: Dal‐Cin Mauro M. , Guiver Michael D. , Striez Carolyn N. , Carlsson Dave J. , Kumar Ashwani 
Published: May 2006

AbstractPolysulfone (Udel P1800) ultrafiltration membranes were surface modified using potassium persulfate (K2S2O8) as a free radical source in the aqueous phase. The expected modification was hydrogen abstraction leading to hydroxylation at one or two sites on the isopropylidene linkage. Reaction time, K2S2O8 concentration, and temperature were optimized based on two criteria: (1) minimal change in pure water fluxes after surface modification and (2) reduction of adsorptive fouling with a pulp mill effluent. The pure water flux retention for an unmodified membrane was ∼20% after adsorptive fouling with the pulp mill effluent and was increased to 70% after reaction with K2S2O8. Angle‐resolved XPS indicated increased oxygen and a new carbon peak consistent with an aldehyde reaction occurring in the top 3.5 nm. NMR solution analysis was inconclusive because of the low sensitivity of the experiment. Further analysis of oxidation products was carried out on finely dispersed polymer. Fourier transform infrared, internal reflection spectroscopy suggested oxidation by the formation of an aldehyde which was further oxidized to carboxylic acid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1723–1730, 2006
Application of Fourier transform infrared spectroscopy in the study of interactions between PVC and plasticizers: PVC/plasticizer compatibility versus chemical structure of plasticizer
Authors: González N. , Fernández‐Berridi M. J. 
Published: May 2006

AbstractFourier transform infrared spectroscopy is applied in the study of interactions between PVC resin and plasticizers in flexible PVC systems. The comparison of the theoretical infrared spectra coming from the addition of the respective component infrared spectra with those of PVC/plasticizer experimental systems gives information about polymer/plasticizer interaction degree. In addition, solvation capacity of the plasticizer varies as a function of its chemical structure, giving rise to compatibility differences between the system components. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1731–1737, 2006
Synthesis, characterization, and pressure‐sensitive properties of butyl acrylate and methyl acrylate copolymers
Authors: Wang Chiliang , Wang Li , Chen Chang , Chen Tao , Jiang Guohua 
Published: May 2006

AbstractButyl acrylate and methyl acrylate copolymers were prepared and evaluated as pressure‐sensitive adhesives. The effects of polymerization conditions such as the temperature, time, amounts of the monomers, and feeding method on the molecular weight, molecular weight distribution, and composition of the resultant copolymers were investigated. The adhesive properties were evaluated in terms of the viscosity, peel strength, and hold time. The best molar ratio of methyl acrylate in the copolymer was 0.466 for pressure‐sensitive adhesives. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1535–1542, 2006
Catalytic effect of 2,2′‐diallyl bisphenol A on thermal curing of cyanate esters
Authors: Koh Henry C. Y. , Dai Jie , Tan Eileen , Liang Weirong 
Published: May 2006

AbstractCyanate esters are a class of thermal resistant polymers widely used as thermal resistant and electrical insulating materials for electric devices and structural composite applications. In this article, the effect of 2,2′‐diallyl bisphenol A (DBA) on catalyzing the thermal curing of cyanate ester resins was studied. The curing behavior, thermal resistance, and thermal mechanical properties of these DBA catalyzed cyanate ester resins were characterized. The results show that DBA is especially suitable for catalyzing the polymerization of the novolac cyanate ester resin (HF‐5), as it acts as both the curing catalyst through depressing the exothermic peak temperature (Texo) by nearly 100°C and the toughening agent of the novolac cyanate ester resin by slightly reducing the elastic modulus at the glassy state. The thermogravimetric analysis and dynamic mechanical thermal analysis show that the 5 wt % DBA‐catalyzed novolac cyanate ester resin exhibits good thermal resistance with Td5 of 410°C and the char yield at 900°C of 58% and can retain its mechanical strength up to 250°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1775–1786, 2006
1‐(bromoacetyl)pyrene and its arsonium salt as novel photoinitiators for styrene polymerization
Authors: Mishra Anuradha , Daswal Swati 
Published: May 2006

AbstractThe photopolymerization of styrene (Sty) in DMSO induced by pyrene (Py), 1‐Acetylpyrene (AP), 1‐(Bromoacetyl) pyrene (BP), and 1‐Acetylpyrene triphenyl arsonium bromide (APAS) has been investigated. Under all conditions employed, Py was completely ineffective. Incorporation of a chromophoric (COCH3) moiety introduces photoinitiating activity into Py. It was observed that introduction of Br into AP markedly accelerated the rate of UV irradiation‐induced polymerization. BP was further modified to its arsonium salt (APAS). The kinetics and mechanism of polymerization using BP and APAS as initiators have been investigated in detail. The polymerization with BP followed nonideal kinetics (Rp ∝ [BP]0.8 [Sty]1.1) with respect to initiator concentration whereas ideal kinetics (Rp ∝ [APAS]0.48 [Sty]1.1) was observed when APAS was used as initiator. Degradative transfer is thought to be mainly responsible for this unusual kinetic behavior for BP–Sty system. The kinetic data proved that BP was more effective and faster initiator than APAS. In both the cases, the mechanism of polymerization was free radical as evident by inhibiting the effect of hydroquinone and ESR studies. IR and NMR spectra showed the atactic nature of polystyrene. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1793–1798, 2006
Dynamic mechanical and thermal properties of plasticized poly(lactic acid)
Authors: Ren Zhongjie , Dong Lisong , Yang Yuming 
Published: May 2006

AbstractThe blends of low molecular weight triacetin (TAC) and oligomeric poly(1,3‐butylene glycol adipate) (PBGA) were used as multiple plasticizers to lubricate poly(lactic acid) (PLA) in this study. The thermal and mechanical properties of plasticized polymers were investigated by means of dynamic mechanical analysis and differential scanning calorimetry. Atomic force microscopy (AFM) was used to analyze the morphologies of the blends. Multiple plasticizers were effective in lowering the glass transition temperature (Tg) and the melting temperature (Tm) of PLA. Moreover, crystallinity of PLA increased with increasing the content of multiple plasticizers. Tensile strength of the blends decreased following the increasing of the plasticizers, but increased in elongation at break. AFM topographic images showed that the multiple plasticizers dispersed between interfibrillar regions. Moreover, the fibrillar crystallite formed the quasicrosslinkings, which is another cause for the increase in elongation at break. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1583–1590, 2006
Modification of polyethersulphone induced by high energy proton, C+, and Ne6+ ions: A spectroscopic study
Authors: Vinodh Kumar S. , Ghadei B. , Jal P. K. , Dey K. , Krishna J. B. M. , Saha A. 
Published: May 2006

AbstractPolyethersulphone (PES) was irradiated with 4 MeV proton, 3.6 MeV C+, and 145 MeV Ne6+ ions at different ion fluences. The linear energy transfer dependence on ion‐induced spectral changes was analyzed by ultraviolet–visible, Fourier transform infrared spectroscopy and fluorescence spectroscopy. The gradual red shift with the increase in optical absorption was observed in the region of 350–500 nm for proton and 400–800 nm for C+ and Ne6+ ions irradiated PES. The gradual shift in absorption may be attributed to the formation of carbonaceous clusters. The gradual decrease in optical band gap indicates increase in cluster sizes. When PES was irradiated with protons, loss in fluorescence emission intensity at 440 nm was observed, although there was no change in spectral shape. In contrast, C+ and Ne6+ ion irradiated PES showed blue shift with concomitant loss in intensity and the formation of new peak at 575 nm. In fact, heavier ions are found to be more effective in inducing physicochemical modifications in PES. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1591–1597, 2006
ATRP of acrylonitrile catalyzed by FeCl2/succinic acid under microwave irradiation
Authors: Hou Chen , Qu Rongjun , Ji Chunnuan , Wang Chunhua , Sun Changmei 
Published: May 2006

AbstractA single‐pot atom‐transfer radical polymerization (ATRP) under microwave irradiation was first used to successfully synthesize polyacrylonitrile. This was achieved by using FeCl2/succinic acid as the catalyst and 2‐chloropropionitrile as the initiator. Using the same experimental conditions, the apparent rate constant under microwave irradiation was found to be higher than that under conventional heating. The FeCl2/succinic acid ratio of 1 : 2 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. When FeCl2 was replaced with CuCl, ATRP of AN does not show an obvious living characteristics. To demonstrate the active nature of the polymer chain end, the polymers were used as macroinitiators to proceed the chain‐extension polymerization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1598–1601, 2006
Partial exfoliation and layer expansion of vermiculite layer in solid state by solid state shear milling (S3M) method
Authors: Shao Weiguo , Wang Qi 
Published: May 2006

AbstractA new method, solid state shear milling (S3M), was reported for realizing the exfoliation and layer expansion of vermiculite layer in solid state by using pan‐mill equipment, which can exert fairly strong squeezing force and shearing force on milled materials. The mechanism was discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1806–1809, 2006
Modeling heat and degree of gelation for methyl cellulose hydrogels with NaCl additives
Authors: Joshi S. C. , Lam Y. C. 
Published: May 2006

AbstractMethyl cellulose (MC) hydrogels are thermoreversible physical hydrogels and their gelation is an endothermic process. A model consisting of a generalized expression for two bell‐shape curves was formulated to describe and capture enthalpy changes that take place during the gelation of an aqueous solution of MC, SM4000, in the presence of sodium chloride, NaCl, in different concentrations. The procedure followed in obtaining the necessary constants for the model using the differential scanning calorimetric (DSC) measurements is elaborated. The developed model described the salt‐out effects of NaCl in various % on the MC gelation very well. One of the two bell‐shape curves mapped most part of the DSC thermograms. The secondary bell‐shape curves portrayed the minor enthalpy changes. The possible mechanisms and molecular bonding processes driven by the energy represented by the area under these two individual curves are discussed. Subsequently, a sigmoidal growth model for the degree of gelation was introduced, and its development is explained in the paper. The import of various constants for these two models, the bell‐shape curves and the sigmoidal growth models, in terms of gelation kinetics is identified. The need for a specific term of the sigmoidal model for depicting the effect of the salt additive onto the gelation is recognized. The comparison between the results obtained using these two models is discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1620–1629, 2006