bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insulin-like growth factor-1 protects ischemic murine myocardium from ischemia/reperfusion associated injury
Authors: Davani Ehsan Y , Brumme Zabrina , Singhera Gurpreet K , Côté Hélène CF , Harrigan P Richard , Dorscheid Delbert R 
Published: October 2003

Abstract
Introduction
Ischemia/reperfusion occurs in myocardial infarction, cardiac dysfunction during sepsis, cardiac transplantation and coronary artery bypass grafting, and results in injury to the myocardium. Although reperfusion injury is related to the nature and duration of ischemia, it is also a separate entity that may jeopardize viable cells and ultimately may impair cardiac performance once ischemia is resolved and the organ heals.

Method
The present study was conducted in an ex vivo murine model of myocardial ischemia/reperfusion injury. After 20 min of ischemia, isolated hearts were perfused for up to 2 hours with solution (modified Kreb's) only, solution plus insulin-like growth factor (IGF)-1, or solution plus tumor necrosis factor (TNF)-α. Cardiac contractility was monitored continuously during this period of reperfusion.

Results
On the basis of histologic evidence, IGF-1 prevented reperfusion injury as compared with TNF-α; TNF-α increased perivascular interstitial edema and disrupted tissue lattice integrity, whereas IGF-1 maintained myocardial cellular integrity and did not increase edema. Also, there was a significant reduction in detectable creatine phosphokinase in the perfusate from IGF-1 treated hearts. By recording transduced pressures generated during the cardiac cycle, reperfusion with IGF-1 was accompanied by markedly improved cardiac performance as compared with reperfusion with TNF-α or modified Kreb's solution only. The histologic and functional improvement generated by IGF-1 was characterized by maintenance of the ratio of mitochondrial to nuclear DNA within heart tissue.

Conclusion
We conclude that IGF-1 protects ischemic myocardium from further reperfusion injury, and that this may involve mitochondria-dependent mechanisms.
Synthesis and characterization of side‐chain liquid‐crystalline ionomers containing quaternary ammonium salt groups
Authors: Tong Bin , Zhang Baoyan , Hu Jianshe , Dai Rongji , Deng Yulin 
Published: October 2003

AbstractA series of thermotropic side‐chain liquid‐crystalline ionomers (LCIs) containing 4‐(4‐alkoxybenzyloxy)‐4′‐allyloxybiphenyl (M) as mesogenic units and allyl triethylammonium bromide (ATAB) as nonmesogenic units were synthesized by graft copolymerization upon polymethylhydrosiloxane. The chemical structures of the polymers were confirmed by IR spectroscopy. DSC was used to measure the thermal properties of these polymers. The mesogenic properties were characterized by polarizing optical microscopy, DSC, and X‐ray diffraction. Homopolymers without ionic groups exhibit smectic and nematic mesophases. The nematic mesophases of the ionomers disappear and the mesomorphic temperature ranges decrease with increasing concentration of ionic units. The influence of the alkoxy chain length on clearing temperature (Tc) values of ionomers clearly shows an odd‐even effect, similar to that of other side‐chain liquid‐crystalline polymers. The mesomorphic temperature ranges increase with increasing alkoxy chain length when the number of alkoxy carbon is over 3. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2879–2886, 2003
Physicomechanical, optical, barrier, and WAXS studies of filled linear low‐density polyethylene films
Authors: Siddaramaiah  , Jeevananda T. , Jagadeesh K. S. , Somashekarappa H. , Somashekar R. 
Published: October 2003

AbstractLinear low‐density polyethylene (LLDPE) with different fillers such as silica, mica, and soy protein isolate were compounded using a single screw extruder and blown into films by a Konark blow‐film machine. The filled LLDPE films were characterized for physicomechanical and optical properties. Barrier properties such as water vapor transmission rate and oxygen transmission rate of the filled LLDPE films were also reported. Microcrystalline parameters such as crystal size (〈N〉) and lattice distortion (g in %) of the filled LLDPE films were estimated from the wide‐angle X‐ray scattering method using Hosemann's paracrystalline model. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2938–2944, 2003
Structure–property relationship of starch‐filled chain‐extended polyurethanes
Authors: Kendaganna Swamy B. K. , Siddaramaiah  
Published: October 2003

AbstractChain‐extended polyurethane (PU) elastomers were prepared using castor oil with 4,4′‐methylene bis (phenyl isocyanate) (MDI) as a crosslinker and 4,4′‐diamino diphenyl sulphone (DDS) as an aromatic diamine chain extender. A series of starch‐filled (from 5 to 25% wt/wt) diamines chain‐extended PUs have been prepared. The starch‐filled PU composites were characterized for physico‐mechanical properties viz, density, surface hardness, tensile strength, and percentage elongation at break. Thermal stability of PU/starch have been carried out by using thermogravimetric analyzer (TGA). Thermal degradation process of PU/starch were found to proceed in three steps. TGA thermograms of PU/starch shows that all systems were stable upto 235°C, and maximum weight loss occur at temperature 558°C. The microcrystalline parameters such as crystal size (〈N〉) and lattice strain (g in %) of PU/starch have been established using wide‐angle X‐ray scattering (WAXS) method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2945–2954, 2003
Effect of different skin permeation enhancers on peel strength of an acrylic PSA
Authors: Taghizadeh S. M. , Lahootifard F. 
Published: October 2003

AbstractDifferent amounts of two skin permeation enhancers, Oleic acid (OA) and Propylene glycol (PG), were mixed thoroughly with solution of a commercial acrylic pressure sensitive adhesive (Duro‐Tak). Films with different adhesive layer thickness (30 and 60 μm) were prepared by casting of formulations with a film applicator on a PET 80‐μm film and drying of solvents. Peel test was done on different formulations according to ASTM D3330. Surface study and thermal analysis were used for explaining the results. It was shown that the effect of interfacial work of adhesion on peel strength was too low to be considered. PG had no significant effect on peel strength, which was related to effect of hydrogen bonds between PG and copolymer chains acting as crosslinks. OA decreased peel strength significantly, which is due to important changes in copolymer structure. These changes can be found by relatively sharp drop in Tg values. Adhesive–cohesive transition occurred in OA formulations as a result of OA crystals formation. OA migration to surface in concentrations of more than 10 (w/w %) was confirmed by results of DSC and surface study. In contrast with PG, doubling of thickness had no effect on peel strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2987–2991, 2003
Viable utilization of polycarbonate as a phosgene equivalent illustrated by reactions with alkanedithiols, mercaptoethanol, aminoethanethiol, and aminoethanol: A solution for the issue of carbon resource conservation
Authors: Hata Sohei , Goto Hiroko , Tanaka Saki , Oku Akira 
Published: October 2003

AbstractMethods for the chemical recycling of polycarbonate (PC) wastes in the forms of bisphenol A (BPA) and cyclic heterocarbonates, such as 1,3‐dithiolan‐2‐one (DTO), 1,3‐dithiane‐2‐one (DTA), and cyclic unsymmetric heterocarbonates, were investigated to prove that PC can be utilized as a phosgene equivalent for industrial purposes. Treatment of PC pellets or waste PC compact discs with 1,2‐ethanedithiol and a catalytic amount of base (e.g., 1.5 mol % NaOH) in dioxane for a short period at 40°C produced DTO and BPA, both in nearly quantitative yields. The reaction could also be carried out in DTO, which saved the use of conventional solvents. Other cyclic heterocarbonates, that is, DTA, 1,3‐oxathiolan‐2‐one, 1,3‐thiazolidine‐2‐one, and N‐methyl‐1,3‐oxazolidine‐2‐one, were prepared in high yields under analogous conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2959–2968, 2003
Synthesis and characterization of novel copolymers with acid‐labile ketal moieties derived from camphor
Authors: Liu Jui‐Hsiang , Wang Hung‐Yu 
Published: October 2003

AbstractNovel diastereomeric acrylic ketal monomers derived from (+)‐camphor and (±)‐camphor were synthesized. To investigate the applications of the camphor derivatives on positive‐tone photoresists, the acrylic ketal monomers were copolymerized with methyl methacrylate, methacrylic acid, and n‐butyl methacrylate. The optical activities of the chiral monomers and polymers were all evaluated. After UV irradiation and postexposure baking, the optical activity of the polymers decreased because of the decomposition of the acid‐labile pendant chiral groups. The existence of alicyclic camphyl groups increased the etching resistance of the photoresists. The thermogravimetric properties of the copolymers, the exposure curves, the lithographic evaluation of the positive‐tone photoresists, and the effects of alicyclic groups on the plasma etching resistance of the copolymers were all investigated. A resolution of a line‐and‐space pattern of 0.3 μm was achieved. Acid‐catalyzed dehydration crosslinking was also found in this system. Sufficient UV irradiation and heat treatment could cause the acid‐catalyzed dehydration crosslinking of pendant carboxyl groups and thereby increase the efficiency of the thermal resistance of the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2969–2978, 2003
Effect of gas channel design on the molding window of gas‐assisted‐injection‐molded polystyrene parts
Authors: Chien Rean Der , Chen Shia‐Chung , Lin Ming‐Chung , Lee Ping‐Hui , Chen Chun‐Sheng 
Published: October 2003

AbstractGas channel design plays a dominant role in determining the successful application of gas‐assisted injection molding. Although empirical guidelines for gas channel design have been proposed by the various equipment suppliers, quantitative criteria based on well‐designed experiments have not been reported yet. In this study, transparent polystyrene plates designed with semicircular gas channels of different radii and with rectangular gas channels of different width‐to‐height ratios were gas‐assisted‐injection‐molded to investigate the geometrical effects on gas penetration with various plate thicknesses. Plate parts designed with gas channels having four different types of cross sections but with the same section area were also examined. Molding windows and criteria for gas penetration were properly chosen so that the design rule could be defined quantitatively. The moldability index was also classified into five levels (excellent, good, fair, poor, and bad) based on the relative areas of the molding windows. From a plot of the moldability index versus the ratio of the equivalent gas channel radius to the plate thickness, we found that the ratio should be approximately greater than 2 for an appropriate molding window (fair moldability index) to be obtained. The dimensional ratio of the width to the height for rectangular gas channels also affected the moldability index under the same equivalent radius. Meanwhile, for four gas channel designs, both gas channel designs attached to the top rib provided better moldability than the other designs. This investigation offers part designers preliminary quantitative design and molding guidelines for choosing an effective gas channel design that allows the parts to be molded under an appropriate molding window so that the uncertainty in both simulation and process control can be overcame. Furthermore, this study provides a methodology for the establishment of quantitative gas channel design guidelines. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2979–2986, 2003
Modeling shear thickening in dilute polymer solutions: Temperature, concentration, and molecular weight dependencies
Authors: Jiang B. , Keffer D. J. , Edwards B. J. , Allred J. N. 
Published: October 2003

AbstractThe Two Coupled Maxwell Modes (TCMM) Model is applied to give quantitative descriptions of shear‐thickening behavior, which can be observed under certain conditions for high molecular weight polymers dissolved in low viscosity solvents. The TCMM Model is written in terms of five parameters representing the relaxation time of each mode, the concentration of each mode, and a coupling parameter between the two modes. Using all of the available experimental data for steady‐shear viscosity and dichroism we found in the literature, we performed a full parameterization of these five quantities. Furthermore, from this parameterization we can describe the functional dependencies of the relaxation times, modal concentrations, and coupling parameter as functions of temperature, concentration, and molecular weight of the polymer. These functional dependencies are explained in light of the underlying physics imbedded in the TCMM Model. We demonstrate that by optimizing to only the viscosity data, we were able to obtain the same relaxation times, modal concentrations, and coupling parameter as using both the viscosity and dichroism data. This is useful because typically the experimental dichroism data is not available. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2997–3011, 2003
Curing kinetics and chemorheology of epoxy/anhydride system
Authors: Ivankovic M. , Incarnato L. , Kenny J. M. , Nicolais L. 
Published: October 2003

AbstractThe curing kinetics and chemorheology of a low‐viscosity laminating system, based on a bisphenol A epoxy resin, an anhydride curing agent, and a heterocyclic amine accelerator, are investigated. The curing kinetics are studied in both dynamic and isothermal conditions by means of differential scanning calorimetry. The steady shear and dynamic viscosity are measured throughout the epoxy/anhydride cure. The curing kinetics of the thermoset system is described by a modified Kamal kinetic model, accounting for the diffusion‐control effect. A chemorheological model that describes the system viscosity as a function of temperature and conversion is proposed. This model is a combination of the Williams–Landel–Ferry equation and a conversion term originally used by Castro and Macosko. A good agreement between the predicted and experimental results is obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3012–3019, 2003
Solution and solid state nuclear magnetic resonance investigation of poly(methylmethacrylate)/ poly(ethylene oxide) blends
Authors: Diniz Teresinha M. F. F , Tavares Maria I. B. 
Published: October 2003

AbstractIt is well known that nuclear magnetic resonance spectroscopy (NMR) is a powerful method to characterize blends compatibility at the molecular level. In this work binary blends formed by poly(methylmethacrylate)/poly(ethylene oxide), PMMA/PEO, were investigated by different solution and solid state NMR techniques to obtain information on blends homogeneity and compatibility. It was characterized that the values of T1Hρ obtained by variable contact time and delayed contact time experiments, for each composition, were distinct and this fact suggests that regions with different molecular mobilities exist, as a consequence of blending interaction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2955–2958, 2003
Characterization of epoxy foams
Authors: Stefani P. M. , Barchi A. Tejeira , Sabugal J. , Vazquez A. 
Published: October 2003

AbstractEpoxy foams were prepared from the commercial system (LY 5054 epoxy resin, HY 5054 amine as curing agent, and DY 5054 siloxane as foaming agent) supplied by Ciba‐Geigy. From the differential scanning calorimeter results the optimal epoxy–amine ratio was determined. A maximum Tg∞ value of 85°C was found for an epoxy–amine ratio of 100:35 by weight. In this system, the siloxane reacts with the amine releasing hydrogen that acts as the real foaming agent. The density decreased from 490 to 215 kg/m3 as the epoxy:blowing agent ratio increased from 100:1 to 100:3 by weight of the reactive mixture. Under the synthesizing conditions, the glass transition temperature (Tg∞) of the foam did not vary significantly as the blowing agent increased. The modulus and compressive strength of the foam exhibited a power‐law dependence with respect to density of the form: E∝(ρ)n, where n=1.8. Scanning electron microscopy analysis verified that the foam have a closed cell structure. The relation between composition, final morphology, density, and properties of the foam was analyzed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2992–2996, 2003
Poly(ether ether ketone)/poly(aryl ether sulfone) blends: Relationships between morphology and mechanical properties
Authors: Nandan Bhanu , Kandpal L. D. , Mathur G. N. 
Published: October 2003

AbstractMechanical properties such as the tensile modulus, yield (break) strength, and elongation to break (or yield) are measured for multiphase poly(ether ether ketone) (PEEK)/poly(aryl ether sulfone) (PES) blends. Specimens with three different levels of thermal histories (quenched, as‐molded, and annealed) are prepared in order to study their effects on the mechanical properties of PEEK/PES blends. Synergistic behavior is observed in the tensile modulus and tensile strength of the blends in almost the whole range of compositions. The ductility of quenched blends measured as the elongation to break (yield) shows an unexpected synergistic behavior in the blend containing 90 wt % PEEK, although a negative deviation from additive behavior is observed in the rest of the compositions. A ductile–brittle transition is observed between 50 and 75 wt % PEEK in the blend. The ductile–brittle transition in as‐molded blends shifts to 75–90 wt % PEEK. Annealed blends show predominantly brittle behavior in the whole composition range. The experimental data are further correlated with the theoretically predicted results based on various composite models. Although the prediction based on these equations fails to fit the experimental data in the whole composition range, the simplex equations that are normally used for blends showing synergistic behavior produced a reasonable fit to the experimental data. The mechanical properties obtained for different blend compositions are further correlated with their morphology as observed by scanning electron microscopy. Morphological observation shows a two‐phase morphology in PES‐rich blends, which is an interlocked morphology in which the disperse phase is not clearly visible in PEEK‐rich blends, and a cocontinuous type of morphology for a 50/50 composition. Considerable permanent deformation of both the disperse and matrix phase, especially in the case of quenched tensile specimens, demonstrates the remarkable adhesion present between the two phases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2887–2905, 2003
Crystallization and melting behavior of poly(ether ether ketone)/poly(aryl ether sulfone) blends
Authors: Nandan Bhanu , Kandpal L. D. , Mathur G. N. 
Published: October 2003

AbstractThe crystallization and melting behavior of poly(ether ether ketone) (PEEK) in blends with poly(aryl ether sulfone) (PES) prepared by melt mixing are investigated by differential scanning calorimetry (DSC) and wide‐angle X‐ray scattering (WAXS). The presence of PES is found to have a notable influence on the crystallization behavior of PEEK, especially when present in low concentrations in the PEEK/PES blends. The PEEK crystallization kinetics is retarded in the presence of PES from the melt and in the rubbery state. An analysis of the melt crystallization exotherm shows a slower rate of nucleation and a wider crystallite size distribution of PEEK in the presence of PES, except at low concentrations of PES, where, because of higher miscibility and the tendency of PES to form ordered structures under suitable conditions, a significantly opposite result is observed. The cold crystallization temperature of the blends at low PES concentration is higher then that of pure PEEK, whereas at a higher PES concentration little change is observed. In addition, the decrease in heat of cold crystallization and melting, which is more prevalent in PEEK‐rich compositions than in pure PEEK, shows the reduction in the degree of crystallinity because of the dilution effect of PES. Isothermal cold crystallization studies show that the cold crystallization from the amorphous glass occurs in two stages, corresponding to the mobilization of the PEEK‐rich and PES‐rich phases. The slower rate of crystallization of the PEEK‐rich phase, even in compositions where a pure PEEK phase is observed, indicates that the presence of the immobile PES‐rich phase has a constraining influence on the crystallization of the PEEK‐rich phase, possibly because of the distribution of individual PEEK chains across the two phases. The various crystallization parameters obtained from WAXS analysis show that the basic crystal structure of PEEK remains unaffected in the blend. Further, the slight melting point depression of PEEK at low concentrations of PES, apart from several other morphological reasons, may be due to some specific interactions between the component homopolymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2906–2918, 2003
Preparation and properties of transparent cellulose hydrogels
Authors: Saito Hidenao , Sakurai Akihiko , Sakakibara Mikio , Saga Hiroshi 
Published: October 2003

AbstractHighly transparent cellulose hydrogels with physical crosslinkage were prepared from nonaqueous organic cellulose solutions and viscose by coagulating and regenerating cellulose in an aqueous solution containing a water‐miscible organic solvent. Nonaqueous organic cellulose solutions used were LiCl/dimethylacetamide, paraformaldehyde/dimethyl sulfoxide, and triethylammonium chloride/dimethyl sulfoxide. Preparation conditions and physical properties of the transparent cellulose hydrogels were studied. The transparency of the cellulose hydrogels depended on the composition of the aqueous solution containing the organic solvent. Furthermore, transparent cellulose hydrogels from viscose showed high tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3020–3025, 2003
Impact modification of poly(ethylene terephthalate)
Authors: Chapleau N. , Huneault M. A. 
Published: October 2003

AbstractThe tensile and impact resistance of impact‐modified poly(ethylene terephthalate) (PET) is investigated. The impact modifiers are polyolefin‐based elastomers or elastomer blends containing glycidyl methacrylate moieties to improve the adhesion with the polyester. The tensile properties are measured on injection molded specimens at room temperature while the Izod impact strength is measured from −40 to 20°C. The blend morphology is observed by scanning electron microscopy and the dispersed phase average diameter is determined by image analysis. The relation between the impact resistance and the phase morphology is discussed, and the critical ligament size for PET is determined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2919–2932, 2003
Antimicrobial effect of monomers and polymers with azole moieties
Authors: Moon Woong‐Sig , Chung Kyoo‐Hyun , Seol Du Jin , Park Eun‐Soo , Shim Jae‐Hun , Kim Mal‐Nam , Yoon Jin‐San 
Published: October 2003

AbstractFive monomers with azole moieties were synthesized and their antimicrobial activities were investigated. The antimicrobial activity of the monomers was evaluated by the halo zone test method. The results strongly depended on the chemical structure of the group attached to the azole moieties. Polymers with (benzimidazol‐2‐yl)thio groups and with (5‐methyl‐1,3,4‐thiadiazol‐2‐yl)thio groups were synthesized. The shake flask test showed that the two polymers possessed excellent antimicrobial activity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2933–2937, 2003