bluuebunny/crossref_metadata_2025 huggingface dataset:
Coincident Linkage of Type 2 Diabetes, Metabolic Syndrome, and Measures of Cardiovascular Disease in a Genome Scan of the Diabetes Heart Study
Authors: Bowden Donald W. , Rudock Megan , Ziegler Julie , Lehtinen Allison B. , Xu Jianzhao , Wagenknecht Lynne E. , Herrington David , Rich Stephen S. , Freedman Barry I. , Carr J. Jeffrey , Langefeld Carl D.
Published: June 2006

Cardiovascular disease (CVD) is a major contributor to morbidity and mortality in type 2 diabetes, but the relationship between CVD and type 2 diabetes is not well understood. The Diabetes Heart Study is a study of type 2 diabetes–enriched families extensively phenotyped for measures of CVD, type 2 diabetes, and metabolic syndrome. A total of 977 Caucasian subjects from 358 pedigrees (575 type 2 diabetic relative pairs) with at least two individuals with type 2 diabetes and, where possible, unaffected siblings were included in a genome scan. Qualitative traits evaluated in this analysis are with or without the presence of coronary calcified plaque (CCP) and with or without carotid calcified plaque (CarCP) measured by electrocardiogram–gated helical computed tomography. In addition, prevalent CVD was measured using two definitions: CVD1, based on self-reported history of clinical CVD (393 subjects), and CVD2, defined as CVD1 and/or CCP >400 (606 subjects). These discrete traits (type 2 diabetes, metabolic syndrome, CVD1, CVD2, CCP, and CarCP) frequently coincide in the same individuals with concordance ranging from 42.9 to 99%. Multipoint nonparametric linkage analysis revealed evidence for coincident mapping of each trait (type 2 diabetes, metabolic syndrome, CVD1, CVD2, CCP, and CarCP) to three different genomic regions: a broad region on chromosome 3 (70–160 cM; logarithm of odds [LOD] scores ranging between 1.15 and 2.71), chromosome 4q31 (peak LOD 146 cM; LOD scores ranging between 0.90 and 2.41), and on chromosome 14p (peak LOD 23 cM; LOD scores ranging between 1.43 and 2.31). Ordered subset analysis (OSA) suggests that the linked chromosome 3 region consists of at least two separate loci on 3p and 3q. In addition, OSA based on lipid measures and other traits identify family subsets with significantly stronger evidence of linkage (e.g., CVD2 on chromosome 3 at 87 cM subsetting on low HDL with an initial LOD of 2.19 is maximized to an LOD of 7.04 in a subset of 25% of the families and CVD2 on chromosome 14 at 22 cM subsetting on high triglycerides with an initial LOD of 1.99 maximized to an LOD of 4.90 in 44% of the families). When subjects are defined as affected by the presence of each trait (type 2 diabetes, metabolic syndrome, CVD1, and CCP), significant evidence for linkage to the 3p locus is observed with a peak LOD of 4.13 at 87 cM. While the correlated nature of the traits makes it unclear whether these loci represent distinct type 2 diabetes, metabolic syndrome, or CVD loci or single loci with pleiotropic effects, the coincident linkage suggests that identification of the underlying genes may help clarify the relationship of diabetes, metabolic syndrome, and CVD.
ACE and ACE2 Activity in Diabetic Mice
Authors: Wysocki Jan , Ye Minghao , Soler Maria José , Gurley Susan B. , Xiao Hong D. , Bernstein Kenneth E. , Coffman Thomas M. , Chen Sheldon , Batlle Daniel
Published: June 2006

ACE-related carboxypeptidase (ACE2) may counterbalance the angiotensin (ANG) II–promoting effects of ACE in tissues where both enzymes are found. Alterations in renal ACE and ACE2 expression have been described in experimental models of diabetes, but ACE2 activity was not assessed in previous studies. We developed a microplate-based fluorometric method for the concurrent determination of ACE and ACE2 activity in tissue samples. Enzymatic activity (relative fluorescence unit [RFU] · μg protein−1 · h−1) was examined in ACE and ACE2 knockout mice and in two rodent models of diabetes, the db/db and streptozotocin (STZ)-induced diabetic mice. In kidney cortex, preparations consisting mainly of proximal tubules and cortical collecting tubules, ACE2 activity had a strong positive correlation with ACE2 protein expression (90-kDa band) in both knockout models and their respective wild-type littermates (r = 0.94, P < 0.01). ACE activity, likewise, had a strong positive correlation with renal cortex ACE protein expression (170-kDa band) (r = 0.838, P < 0.005). In renal cortex, ACE2 activity was increased in both models of diabetes (46.7 ± 4.4 vs. 22.0 ± 4.7 in db/db and db/m, respectively, P < 0.01, and 22.1 ± 2.8 vs. 13.1 ± 1.5 in STZ-induced diabetic versus untreated mice, respectively, P < 0.05). ACE2 mRNA levels in renal cortex from db/db and STZ-induced diabetic mice, by contrast, were not significantly different from their respective controls. In cardiac tissue, ACE2 activity was lower than in renal cortex, and there were no significant differences between diabetic and control mice (db/db 2.03 ± 0.23 vs. db/m 1.85 ± 0.10; STZ-induced diabetic 0.42 ± 0.04 vs. untreated 0.52 ± 0.07 mice). ACE2 activity in renal cortex correlated positively with ACE2 protein in db/db and db/m mice (r = 0.666, P < 0.005) as well as in STZ-induced diabetic and control mice (r = 0.621, P < 0.05) but not with ACE2 mRNA (r = −0.468 and r = −0.522, respectively). We conclude that in renal cortex from diabetic mice, ACE2 expression is increased at the posttranscriptional level. The availability of an assay for concurrent measurement of ACE and ACE2 activity should be helpful in the evaluation of kidney-specific alterations in the balance of these two carboxypeptidases, which are involved in the control of local ANG II formation and degradation.
Common Hepatic Nuclear Factor-4α Variants Are Associated With High Serum Lipid Levels and the Metabolic Syndrome
Authors: Weissglas-Volkov Daphna , Huertas-Vazquez Adriana , Suviolahti Elina , Lee Jenny , Plaisier Christopher , Canizales-Quinteros Samuel , Tusie-Luna Teresa , Aguilar-Salinas Carlos , Taskinen Marja-Riitta , Pajukanta Päivi
Published: June 2006

Hepatic nuclear factor-4α (HNF-4α), a transcription factor involved in the regulation of serum lipid and glucose levels, has recently been associated with type 2 diabetes. The HNF-4α gene (HNF4A) resides on chromosome 20q12-q13.1, which, in addition to type 2 diabetes, has also previously been linked to high triglycerides in Finnish familial combined hyperlipidemia (FCHL) families. FCHL, characterized by elevated levels of serum total cholesterol, triglycerides, or both, is a common dyslipidemia observed in up to 20% of patients with premature coronary heart disease. Considering the clear phenotypic overlap between type 2 diabetes and FCHL, both predisposing to high serum triglycerides and glucose intolerance, we tested this gene for association in dyslipidemic families originating from two distinct populations, Finnish and Mexican, and comprising 1,447 subjects. Our data show that common HNF4A variants and haplotypes are associated with elevated serum lipid levels and the metabolic syndrome (P = 0.008–0.04), as well as with elevated glucose parameters (P = 0.008–0.03), using family-based association analysis. Importantly, both Finnish and Mexican families shared two common lipid-associated HNF4A haplotypes (P = 0.005 for total cholesterol and 0.006 for triglycerides). In conclusion, we show for the first time that common HNF4A variants are associated with high serum lipid levels and the metabolic syndrome.
Plasma Interleukin-6 Levels Are Independently Associated With Insulin Secretion in a Cohort of Italian-Caucasian Nondiabetic Subjects
Authors: Andreozzi Francesco , Laratta Emanuela , Cardellini Marina , Marini Maria A. , Lauro Renato , Hribal Marta L. , Perticone Francesco , Sesti Giorgio
Published: June 2006

We have investigated the relationships between plasma interleukin-6 (IL-6) levels and insulin sensitivity and insulin secretion in a cohort of Italian-Caucasian glucose-tolerant subjects. Insulin sensitivity was assessed by euglycemic-hyperinsulinemic clamp, and first-phase insulin secretion was measured by intravenous glucose tolerance test. Fasting plasma IL-6 concentration was negatively correlated with the rate of insulin-stimulated glucose disposal (M) (P = 0.001). The correlation remained statistically significant, while attenuated, after adjusting for sex, age, and BMI (P < 0.03); after an additional adjustment for free fatty acids (FFAs), a further attenuation was observed, but statistical significance was maintained (P < 0.044). Fasting plasma IL-6 concentration was positively correlated with first-phase insulin secretion assessed as acute insulin response (AIR) (P = 0.001). The correlation remained significant after adjusting for sex, age, and BMI (P = 0.003). To estimate the independent contribution of plasma IL-6 levels to AIR, we carried out forward stepwise linear regression analysis in a model that included sex, age, BMI, waist-to-hip ratio, FFAs, and insulin-stimulated glucose disposal. Only insulin sensitivity and plasma IL-6 concentration were independently associated with AIR, accounting, respectively, for 19.0 and 5.2% of its variation. These data indicate that IL-6 is associated in a reciprocal manner with the two pathophysiological components of type 2 diabetes, i.e., insulin resistance and insulin secretion.
Mitochondrial Reactive Oxygen Species Are Required for Hypothalamic Glucose Sensing
Authors: Leloup Corinne , Magnan Christophe , Benani Alexandre , Bonnet Emilie , Alquier Thierry , Offer Géraldine , Carriere Audrey , Périquet Alain , Fernandez Yvette , Ktorza Alain , Casteilla Louis , Pénicaud Luc
Published: June 2006

The physiological signaling mechanisms that link glucose sensing to the electrical activity in metabolism-regulating hypothalamus are still controversial. Although ATP production was considered the main metabolic signal, recent studies show that the glucose-stimulated signaling in neurons is not totally dependent on this production. Here, we examined whether mitochondrial reactive oxygen species (mROS), which are physiologically generated depending on glucose metabolism, may act as physiological sensors to monitor the glucose-sensing response. Transient increase from 5 to 20 mmol/l glucose stimulates reactive oxygen species (ROS) generation on hypothalamic slices ex vivo, which is reversed by adding antioxidants, suggesting that hypothalamic cells generate ROS to rapidly increase glucose level. Furthermore, in vivo, data demonstrate that both the glucose-induced increased neuronal activity in arcuate nucleus and the subsequent nervous-mediated insulin release might be mimicked by the mitochondrial complex blockers antimycin and rotenone, which generate mROS. Adding antioxidants such as trolox and catalase or the uncoupler carbonyl cyanide m-chlorophenylhydrazone in order to lower mROS during glucose stimulation completely reverses both parameters. In conclusion, the results presented here clearly show that the brain glucose-sensing mechanism involved mROS signaling. We propose that this mROS production plays a key role in brain metabolic signaling.
A Choline-Deficient Diet Exacerbates Fatty Liver but Attenuates Insulin Resistance and Glucose Intolerance in Mice Fed a High-Fat Diet
Authors: Raubenheimer Peter J. , Nyirenda Moffat J. , Walker Brian R.
Published: June 2006

Liver fat accumulation is proposed to link obesity and insulin resistance. To dissect the role of liver fat in the insulin resistance of diet-induced obesity, we altered liver fat using a choline-deficient diet. C57Bl/6 mice were fed a low-fat (10% of calories) or high-fat (45% of calories) diet for 8 weeks; during the final 4 weeks, diets were either choline deficient or choline supplemented. In choline replete animals, high-fat feeding induced weight gain, elevated liver triglycerides (171%), hyperinsulinemia, and glucose intolerance. Choline deficiency did not affect body or adipose depot weights but amplified liver fat accumulation with high-fat diet (281%, P < 0.01). However, choline deficiency lowered fasting plasma insulin (from 983 ± 175 to 433 ± 36 pmol/l, P < 0.01) and improved glucose tolerance on a high-fat diet. In mice on 30% fat diet, choline deficiency increased liver mRNA levels of the rate-limiting enzyme in phosphatidylcholine synthesis and of enzymes involved in free fatty acid esterification, without affecting those of de novo lipogenesis or fatty acid oxidation. We conclude that liver fat accumulation per se does not cause insulin resistance during high-fat feeding and that choline deficiency may shunt potentially toxic free fatty acids toward innocuous storage triglyceride in the liver.
DNA‐Assisted Monolayer Immobilization of 2D Opaline Arrays
Authors: Kim S. , Yang B. , Hou S. , Lee J. , Papadimitrakopoulos F.
Published: June 2006

DNA supramolecular recognition is employed for the immobilization of 2D photonic crystals of monodisperse colloidal microspheres. Amine‐terminated DNA oligomers are covalently attached to carboxy‐decorated microspheres and substrates while preserving their colloidal stability and organization properties. Following a capillary‐force‐assisted organization of DNA‐decorated microspheres into close‐packed 2D opaline arrays, the first monolayer is immobilized by DNA hybridization. Various parameters affecting the long‐range order of such opaline arrays are investigated, including surface hydrophobicity and the relative strengths of the specific versus nonspecific interactions. The type and concentration of salt and the process temperature are also optimized for the hybridization between microspheres and substrate. The selective removal of non‐specifically bound multilayers is accomplished by carefully passing an air/liquid interface over these arrays. DNA hybridization was found to play an important role in immobilizing the first monolayer of 2D opaline arrays while preserving its long‐range order, with an approximate binding strength three times higher than that of non‐specific interactions.
Inside Front Cover: Photonic Crystal Structures as a Basis for a Three‐Dimensionally Interpenetrating Electrochemical‐Cell System (Adv. Mater. 13/2006)
Authors: Ergang N. S. , Lytle J. C. , Lee K. T. , Oh S. M. , Smyrl W. H. , Stein A.
Published: June 2006

The inside cover shows an SEM image of a 3D‐interpenetrating electrochemical cell with submicrometer features, as reported by Stein and coworkers on p. 1750. The pores of an inverse‐opal carbon electrode are coated with a conformal layer of a polymer separator and infiltrated with vanadia to form the opposite electrode after lithiation. The idealized scheme illustrates lithium‐ion transport between the electrodes through the polymer membrane.
In‐situ measurements of temperature distributions in a microwave‐heated cavity
Authors: Finegan Timothy , Laibinis Paul E. , Hatton T. Alan
Published: June 2006

The application of microwave heating technology to chemical processes outside of the food industries has been limited by an incomplete understanding of the temperature distributions formed within a microwave‐heated cavity. A fluorescence‐based optical method of thermometry is described for the in situ measurement of temperature distributions during microwave heating processes. Highly nonuniform, two‐dimensional (2‐D) temperature‐distribution profiles were measured by resolving spatial variations in the fluorescence response of a temperature sensitive dye, Rhodamine B. The dye was excited by illuminating a slice within the sample cell using a planar expanded laser beam. Significant variations in the heating profiles of water and of salt (NaCl) solutions of different concentrations were observed, consistent with the influence of salt concentration on the dielectric properties of the solutions. The experimentally observed spatial variations in temperature before the onset of convection were in good agreement with predictions using a simple model to describe the electric field distributions in the microwave cavity. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Commensalistic cultures with kinetic feedback—Static and dynamic behavior
Authors: Parulekar Satish J. , Ingle Parag A.
Published: June 2006

Steady state and dynamic behavior of continuous mixed cultures of two cell species with commensalistic interaction and kinetic feedback is investigated. The generation of the substrate required for growth of the host cell species from a primary resource is catalyzed by extracellular enzymes produced by the cell species, providing thereby, a kinetic feedback. The steady states are divided into three types. For the form of kinetics considered, the reactor can operate at up to seven steady states, including up to four steady states in which the cell species coexist. Conditions for admissibility and stability of different steady states are derived analytically. Admissibility of cyclic states is investigated. The specific example considered pertains to anaerobic digestion of complex insoluble organics by acid generating and methane generating bacteria. For a specific kinetic parameter set, the operating parameter space is divided into multiple regions based on admissibility of various steady states and dynamic characteristics. Startup policies to reach desired steady states are discussed. © 2006 American Institute of Chemical Engineers AIChE J, 2006
The Italian surveillance system for occupational cancers: Characteristics, initial results, and future prospects
Authors: Crosignani Paolo , Massari Stefania , Audisio Roberto , Amendola Plinio , Cavuto Silvio , Scaburri Alessandra , Zambon Paola , Nedoclan Giovanni , Stracci Fabrizio , Pannelli Franco , Vercelli Marina , Miligi Lucia , Imbriani Marcello , Berrino Franco
Published: June 2006

Background

Occupational cancer monitoring is important for cancer prevention and public health protection. A surveillance system for identifying occupational cancer risks and cancer cases in Italy that are likely to be of occupational origin using information available in the Italian Social Security archives was created and assessed. Persons employed in the private sector, the employing company, its industrial sector, and years of employment are available in these archives.

Methods

A method to find known occupational hazards was first tested using a case‐control approach. Cases were from six Italian cancer registries (CRs) and controls were sampled from source populations and as “exposure” the economic sector of the employing company was used. The potential of using hospital discharge records as case sources was subsequently assessed: these cover larger populations and are available more quickly than CR case series.

Results

In the CR‐based study many known occupational cancer risks related to specific industrial sectors were identified. By using cases from hospital discharge records many industries at risk were identified, as well as cases of recent diagnosis likely to be of occupational origin. However, for some industrial sectors (e.g., the chemical industry) the approach was unable to detect any excess risk. Furthermore, information on employees in important areas like agriculture, self‐employment, and the public sector is not available in the Social Security archives.

Conclusions

This approach appears to be a promising low‐cost method for occupational cancer surveillance, at least for some industries, and can be easily implemented in other countries. Am. J. Ind. Med. 2006. © 2006 Wiley‐Liss, Inc.
Asymmetrische heterogene Katalyse
Authors: Heitbaum Maja , Glorius Frank , Escher Iris
Published: June 2006

Knapper werdende Rohstoffe und ein zunehmender Bedarf an enantiomerenreinen Verbindungen machen die Katalyse und insbesondere die heterogene asymmetrische Katalyse zu einer Schlüsseltechnologie. Von den Anfängen, der Verwendung chiraler Biopolymere wie Seide als Träger für Metallkatalysatoren, zu den modernen Forschungsfeldern hat sich das Gebiet rasant entwickelt. Mesoporöse Träger, nichtkovalente Immobilisierung, metall‐organische Katalysatoren, chirale Modifikatoren: viele Gebiete sind im Aufbruch. Dass hierbei von den Katalysatoren mehr geleistet wird, als nur leichte Abtrennung und Wiederverwendung zu ermöglichen, zeigt dieser Aufsatz. So können z. B. bessere Aktivitäten und Selektivitäten als bei der homogenen Katalyse und zudem neuartige, effiziente Reaktionsmechanismen erhalten werden. Besonders spektakulär ist aber der Ausblick auf hochgeordnete metall‐organische Katalysatoren, die “rational” entwickelt, synthetisiert und strukturell eindeutig charakterisiert werden können, um maßgeschneiderte Katalysatoren zu erhalten.
Characterization and possible agricultural application of polyacrylamide/sodium alginate crosslinked hydrogels prepared by ionizing radiation
Authors: Abd El‐Rehim Hassan A.
Published: June 2006

Polyacrylamide/sodium alginate (PAAm/Na‐alginate) crosslinked copolymers were prepared by using electron beam irradiation. The gel content and the swelling behavior of the obtained copolymers were investigated. The thermal and morphological properties of the prepared copolymers were studied using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The thermal stability of PAAm significantly changed when mixed with Na‐alginate. The addition of PAAm/Na‐alginate copolymer in small quantities to sandy soil increased its ability to retain water. The growth and other responses of the faba bean plant cultivated in a soil treated with PAAm and PAAm/Na‐alginate copolymer were investigated. The growth of the bean plant cultivated in a soil containing PAAm/Na‐alginate was better than that cultivated in soil treated with PAAm. The most significant difference between the PAAm and its alginate copolymer is that the latter partially undergoes radiolytic and enzymatic degradation to produce oligo‐alginate, which acts as a plant growth promoter. The increase in faba bean plant performance by using PAAm/Na‐alginate copolymer suggested its possible use in the agriculture field as a soil conditioner, providing the plant with water as well as oligo‐alginate growth promoter. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3572–3580, 2006
Preparation of ion exchange membranes by preirradiation induced grafting of styrene/divinylbenzene into crosslinked PTFE films and successive sulfonation
Authors: Li Jingye , Ichizuri Shogo , Asano Saneto , Mutou Fumihiro , Ikeda Shigetoshi , Iida Minoru , Miura Takaharu , Oshima Akihiro , Tabata Yoneho , Washio Masakazu
Published: June 2006

Ion exchange membranes (IEMs) were prepared by preirradiation induced grafting of styrene with or without divinylbenzene (DVB) into crosslinked polytetrafluoroethylene (RX‐PTFE) films and successively sulfonated by chlorosulfonic acid. The effects of the DVB concentration and solvent on the kinetic of the graft polymerization were studied. The ion exchange capacity (IEC) values of the prepared membranes ranging from 1.5 to 2.8 mequiv/g were obtained. The degree of swelling increased with the increase in the degree of grafting, while higher crosslinking density of both the RX‐PTFE matrices and the grafts suppressed the degree of swelling. The chemical stabilities of the IEMs were tested by recording the weight of the membranes being soaked in hot H2O2 solutions. The weight‐time curves of the prepared membranes showed one‐step quick decrease due to the decomposition of the poly(styrene‐sulfonic acid) (PSSA) grafts. Higher crosslinking density in both the RX‐PTFE matrices and the grafts improved the chemical stability of the IEMs. The ionic conductivity of the IEMs increases with the increase in the IEC values. The IEMs with IEC values higher than 2.2 mequiv/g hold the higher ionic conductivity than that of Nafion® 112 membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3587–3599, 2006
Structure and properties of composite films prepared from cellulose and nanocrystalline titanium dioxide particles
Authors: Zhou Jinping , Liu Shilin , Qi Jianing , Zhang Lina
Published: June 2006

Composite films were successfully prepared from cellulose and two kinds of nanocrystalline TiO2 particles in a NaOH/urea aqueous solution (7.5 : 11 in wt %) by coagulation with H2SO4 solution. The structure, morphology, and properties of the films were characterized by transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, TGA, tensile testing, UV–vis spectroscopy, and antibacterial test. The results indicated that TiO2 particles in a cellulose matrix maintained the original nanocrystalline structure and properties. TiO2(I) (anatase) and TiO2(II) (the mixture of anatase and rutile) particles exhibited a certain miscibility with cellulose. The tensile strength of two kinds of composite films was higher than 70 and 75 MPa, when the content of TiO2(I) and TiO2(II) was 4 and 11 wt %, respectively. The cellulose composite films containing nanocrystalline TiO2 particles displayed distinct antibacterial abilities and excellent UV absorption. This work provides a potential way for preparing functional composite materials from cellulose and inorganic nanoparticles in a NaOH/urea aqueous solution, without a destruction of the structure and properties of the particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3600–3608, 2006
The preparation and physical properties of UP/montmorillonite nanocomposite by UV radiation curing
Authors: Kim Ho‐Gyum , Han Dong‐Hee , Lim Jeong‐Cheol , Oh Dae‐Hee , Min Kyung‐Eun
Published: June 2006

This article describes the preparation and properties of unsaturated polyester (UP)/montmorillonite (MMT) nanocomposite by UV radiation. Benzildimethylketal and 1‐hydroxy cyclohexyl phenyl ketone (HCPK) as a photoinitiator in UP were photolyzed under nitrogen condition. Analysis of X‐ray diffraction patterns of the composites shows that the interlayer spacing of MMT is substantially increased. The type and amount of photoinitiator affects the level of improvement in mechanical properties, and our results suggest that HCPK is a more efficient photoinitiator of UP curing reaction. The interaction between photoinitiators and MMT should be considered to acquire the reinforcement effect of the dispersed MMT nanolayers. The properties of nanocomposite are dependent upon the amount of MMT. The effect of MMT concentration on thermal and dielectric properties is also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3609–3615, 2006
Barrier properties of chlorobutyl nanoclay composites
Authors: Sridhar V. , Tripathy D. K.
Published: June 2006

Elastomeric materials are used as barriers to protect workers against exposure to chemicals. The effectiveness of a polymer as a chemical protective material depends on the rate of permeation of chemicals through it. The permeation rate is dependent on the type and amount of fillers added into the polymer matrix. In this study, Chlorobutyl nanoclay composites were prepared by addition of organically modified and unmodified nanoclays at different filler loadings. The nanocomposites were swollen in three solvents of varying cohesive energy density until equilibrium and desorption experiments were carried out. The data obtained from desorption experiments was used to determine the diffusion coefficients. The concentration‐dependent diffusion coeffecient (D) was calculated at high and low concentration regions and it was found that D is one‐order less in lower concentration region than in the higher concentration range. The aspect ratio of the nanoclay fillers in the composite was calculated by assuming square and disc shapes and it was found to vary with the type of solvent and the used and filler loading. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3630–3637, 2006
Preparation and characterization of organic–inorganic hybrid composites based on multiepoxy silsesquioxane and cyanate resin
Authors: Lu Tingli , Liang Guozheng , Guo Zhian
Published: June 2006

A multiepoxy cubic silsesquioxane was prepared by the hydrolysis and polycondensation of trifunctional monomer (γ‐glycidoxypropyl)trimethoxysilane in a solvent mixture of methyl isobutyl ketone and anhydrous ethanol with a tetraethyl ammonium hydroxide aqueous solution acting as the catalyst, and it was successfully introduced into a cyanate resin and formed highly crosslinked organic–inorganic hybrid composites on a molecular level via a mutual cure reaction. The properties of the multiepoxy cubic silsesquioxane/bisphenol A dicyanate ester resin composites were investigated, and the results showed that introducing the cubic silsesquioxane unit into the cyanate resin successfully modified the local structure of the molecule, made the chain more rigid, restricted the chain mobility, and eventually improved the thermal stability and flame retardancy of the resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3652–3658, 2006
Synthesis of well‐defined poly(methyl methacrylate) nanoparticles by reverse atom transfer radical polymerization in a microemulsion
Authors: Kai Pan , Yi Dan
Published: June 2006

Well‐defined poly(methyl methacrylate) (PMMA) with an α‐isobutyronitrile group and an ω‐bromine atom as the end groups was synthesized by the microemulsion polymerization of methyl methacrylate (MMA) at 70°C with a 2,2′‐azobisisobutyronitrile/CuBr2/2,2′‐bipyridine system. The conversion of the polymerization reached 81.9%. The viscosity‐average molecular weight of PMMA was high (380,000), and the polydispersity index was 1.58. The polymerization of MMA exhibited some controlled radical polymerization characteristics. The mechanism of controlled polymerization was studied. The presence of hydrogen and bromine atoms as end groups of the obtained PMMA was determined by 1H‐NMR spectroscopy. The shape and size of the final polymer particles were analyzed by scanning probe microscopy, and the diameters of the obtained particles were usually in the range of 60–100 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3670–3676, 2006
Investigation of sensing effects of polystyrene‐graft‐polyaniline for cyanide compounds
Authors: Hosseini S. Hossein
Published: June 2006

Polyaniline and its derivatives have high antioxidative stability and are considered to belong to the most useful conductive polymers for practical application. In this work, we have linked 1,4‐phenylenediamine to poly(styrene‐co‐chloromethylstyrene) and prepared poly(styrene‐co‐p‐aminoanilinemethylstyrene), poly(S‐co‐PAAMS). Polystyrene‐graft‐polyaniline, (PS‐g‐PANi), has been synthesized by adding solution of ammonium persulfate and p‐toluenesufonic acid in water. The conductivity of these polymers was measured by the four‐point probe method. The copolymers produced exhibit electrical conductivity comparable to that of polyaniline. PS‐g‐PANi was also exposed to some cyanide compounds such as hydrocyanic acid (Hydrogen cyanide‐HC), ethanedinitrile (Cyanogen‐CY), cyanogen chloride (Chlorocyan‐CC), and cyanogen bromide (Bromocyan‐BC). The cyanide compounds are classified as blood agents groups, in terms of chemical warfare agents standards. First, we prepared different concentration of blood agents at 50, 100, and 150 ppm and exposed them on PS‐g‐PANi for 2 min. Second, we have drawing conductivity change curves versus time and produced optimum conductivity versus time taken. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3920–3926, 2006
Preparation and properties of poly(silicone‐co‐acrylate)/montmorillonite nanocomposite emulsion
Authors: Feng Xiaoping , Zhong Anyong , Chen Deben
Published: June 2006

Poly (silicone‐co‐acrylate)/montmorillonite nanocomposite emulsion were prepared by in situ intercalative emulsion polymerization of acrylate and organosilicone, in the presence of organic modified montmorillonite (OMMT) with different OMMT contents (0, 0.5, 1, 1.5, and 2 wt %). The nanocomposite emulsions were characterized with X‐ray diffraction (XRD), laser light scattering, fourier transform infrared (FTIR), rheological measurements, surface tension, drying speed, and water absorption property. Results showed that OMMT could improve the properties of emulsion, in other words, the properties of nanocomposite emulsion were better when compared with those of the silicone–acrylate emulsion. The properties of nanocomposite emulsion containing 1 wt % OMMT was the best one, and obtained the following advantages: smaller particle size, faster drying speed, shorter curing time, smaller surface tension, bigger apparent viscosity, and improved resistant water by the incorporation of OMMT. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3963–3970, 2006
Miscibility in binary blends of aromatic and alicyclic polyamides
Authors: Endo Masahiro , Morishima Yasuyuki , Yano Shinichi , Tadano Kenji , Murata Yukinobu , Tsunashima Kenji
Published: June 2006

Miscibility was studied for four polyamide blends of 6I/6T [copolymer consisting of 1,6‐hexamethylene diamine and isophthalic acid (6I) (70 wt %) and terephthalic acid (6T) (30 wt %)] with MXD6 (polyamide of m‐xylenediamine and adipic acid), BAC6 (polyamide of 1,3‐bis(aminomethyl)cyclohexane and adipic acid), TR55 (copolymer consisting of nylon 11 (30 wt %), and polyamide of bis(3‐methyl, 4‐aminocyclohexyl)methane (30 wt %) and isophthalic acid (70 wt %), and CX7323 (polyamide of bis(4‐aminocyclohexyl)methane and dodecanedicarboxylic acid), using differential scanning calorimetry, X‐ray diffraction method, and electronmicroscopic observation. In quenched MXD6/(6I/6T) and BAC6/(6I/6T) blends, MXD6 and BAC6 components were miscible to 6I/6T, but TR55 and CX7323 components were completely phase‐separated from 6I/6T. Interestingly on electronmicroscopic observations, TR55 and CX7323 components were seen as droplets in 6I/6T medium when the content is low, but when 50 wt %, a layered structure was constructed with 6I/6T, reminiscent of morphological structure in block copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3971–3978, 2006
Efficiency of short fibers in filling polymer composites
Authors: Kozlov G. V. , Burya A. I. , Zaikov G. E.
Published: June 2006

The present study showed that in carbon plastics the structure of a short‐fiber system (network) can be described by the effective degree of volume filling or by the fractal dimension of the system. Using the effective degree of filling, synergetic behavior was found, and the filler efficiency of the carbon plastics was characterized within the framework of the fractal model of reinforcement. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3979–3982, 2006
Controlled grafting of polymer brushes on poly(vinylidene fluoride) films by surface‐initiated atom transfer radical polymerization
Authors: Liu Dongmei , Chen Yiwang , Zhang Ning , He Xiaohui
Published: June 2006

Controlled grafting of well‐defined polymer brushes on the poly(vinylidene fluoride) (PVDF) films was carried out by the surface‐initiated atom transfer radical polymerization (ATRP). Surface‐initiators were immobilized on the PVDF films by surface hydroxylation and esterification of the hydroxyl groups covalently linked to the surface with 2‐bromoisobutyrate bromide. Homopolymer brushes of methyl methacrylate (MMA) and poly(ethylene glycol) monomethacrylate (PEGMA) were prepared by ATRP from the α‐bromoester‐functionalized PVDF surface. The chemical composition of the graft‐functionalized PVDF surfaces was characterized by X‐ray photoelectron spectroscopy (XPS) and attenuated total reflectance (ATR)–FTIR spectroscopy. Kinetics study revealed a linear increase in the graft concentration of PMMA and PEGMA with the reaction time, indicating that the chain growth from the surface was consistent with a “controlled” or “living” process. The “living” chain ends were used as the macroinitiator for the synthesis of diblock copolymer brushes. Water contact angles on PVDF films were reduced by surface grafting of PEGMA and MMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3704–3712, 2006
Graft polymerization of octafluoropentyl acrylate on polycaproamide thread
Authors: Storozhakova N. A. , Korotkikh V. A. , Rakhimov A. I. , Danilenko T. I.
Published: June 2006

Octafluoropentyl acrylate [H(CF2CF2)2CH2‐ C(O)CHCH2] and polycaproamide (PA‐6) thread were copolymerized with a tert‐butyl hydroperoxide initiator. The fluorine content of the thread was 0.87–1.33% after copolymerization. The creation of ester polyfluorinated alkyl groups on the end of the polyamide macromolecules by the homolytical substitution of hydrogen atoms in the α‐CH2 group of the HNCH2(CH2)4C(O) chain led to an increase in the tensile strength of the PA‐6 thread. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4028–4029, 2006
The dependence of diffusivity of hydrocarbons in polyvyniltrimethylsilane on molecular mobility level
Authors: Khalikov R. M. , Kozlov G. V. , Zaikov G. E.
Published: June 2006

It is shown that the diffusivity value of various gases in polyvinyltrimethylsilane is controlled by two factors: molecular mobility level, characterized by fractal dimension of chain part between entanglements, and the size of gas‐penetrant molecule. Very strong power dependence of diffusivity on both these factors, explaining very large variation of diffusivity for limited interval of mentioned dimension, is obtained. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4048–4050, 2006
Statistical properties of interparticle/void distance for amorphous plastics toughening
Authors: Kim Nam Ho , Kim Ho Sung
Published: June 2006

Statistical properties of interparticle/void distance (ID) for various particle/void and dispersion types are studied in relation with toughening of plastics using computer‐generated three‐dimensional models. Particle/void size groups adopted were either of constant diameter or of log‐normal distribution. Particles/voids were dispersed at uniform‐random or flocculated with multiple clusters. It was found that IDs are (a) of approximately Gaussian distribution for particles/voids of either a constant diameter or a log‐normal distribution, when they are dispersed at uniform‐random, but (b) not of Gaussian distribution for particle/void sizes of bimodal log‐normal distribution, nor for flocculated log‐normal distribution of particles/voids dispersed with multiple clusters. It was also found that the degree of ID uniformity for a single group of log‐normally sized particles/voids is not sensitive to standard deviation of particle/void size. Mixing effect on ID properties using two groups of log‐normally distributed particles/voids with similar mean particle/void diameters was simulated. It was found that, when a significant amount (36 vol %) of particles/voids of a small mean and standard deviation of ID was mixed with a group of particles/voids of a large mean and standard deviation of ID, mean and standard deviation of ID for the mixture were not substantially lower than those of the group of particles/voids of the large mean and standard deviation of ID. It was also found that the degree of ID uniformity for the mixture of the two groups was lower than those of individual groups, indicating that the mixing has deleterious effect on toughening. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4256–4262, 2006
Dynamic properties of rubber vibration isolators and antivibration performance of a nanoclay‐modified silicone/poly(propylene oxide)–poly(ethylene oxide) copolymer with 20 wt % LiClO4 blend system
Authors: Chiu Hsien‐Tang , Wu Jyh‐Horng , Shong Zhi‐Jian
Published: June 2006

This research explores the interlayer effect, hysteresis behavior, and dynamic antivibration properties of a poly(propylene oxide)–poly(ethylene oxide) copolymer with 20 wt % LiClO4 (PEL) for modified silicone [silicone/polymer electrolyte (SP)] blends with clay and organoclay in various amounts. The results show that the polymer chains of PEL expand the clay gallery distance from 1.21 to 1.84 nm. Clay, after it has been organically modified, is added to SP blends, and its gallery spacing shortens from 2 to 1.7 nm. From the compression hysteresis results, along with the increased content of unmodified clay, the antivibration performance of the blends is elevated. In the dynamic antivibration testing results, along with the addition of clay and organoclay, the dynamic ratio of the blends is decreased; thus, in the vibration isolation performance, there is evidence of an elevated effect. On the other hand, after the clay is modified with ammonium salt, its vibration isolation effect is not better than that of the unmodified clay. In terms of the formulation of the nanocomposites, when the concentration of the clay is less than 4 wt %, it has a better effect on the vibration isolation and antivibration effect of SP blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3713–3720, 2006
Investigating nonlinear viscoelastic properties of molten carbon black/poly(ethylene‐co‐butyl acrylate) composites, using fourier transform rheometry and other test techniques
Authors: Leblanc Jean L. , Jäger Karl‐Michel
Published: June 2006

A series of molten carbon black (CB)/poly(ethylene‐co‐butyl acrylate) (EBA) composites were investigated through Fourier transform (FT) rheometry and other techniques. Filler loadings were above the critical percolation value, and consequently, strongly nonlinear viscoelastic properties were observed, with, in addition, an unusual complexity of carbon black effects when compared with other systems, for instance filled elastomers. FT rheometry appears particularly sensitive to such a complexity with typical variations of torque harmonics, as dynamic torsional strain is increased at constant frequency and temperature. How CB particles are distributed in the material appears as the key to understand experimental results. Indeed, in CB–EBA composites, filler particles concentrate in amorphous regions of the polymer, which are also butyl acrylate (BA)‐rich regions. At room temperature, such composites are basically dual‐phase systems: ethylene segments (PE)‐rich crystallites and CB‐rich amorphous BA regions. Solid‐state mechanical properties reflect this morphology. As temperature increases, crystallites melt down allowing a pseudofluid state to be eventually reached but the dual‐phase morphology is essentially kept. It follows that, under increasing (dynamic) strain, such complex dual‐phase molten systems exhibit a response that initially reflects a contribution from PE‐rich regions, easier to deform than CB‐rich amorphous BA regions, before the expected response of the filled BA phase is observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4071–4082, 2006
Synthesis of cassava starch‐g‐poly(methyl methacrylate) copolymers with benzoyl peroxide as an initiator
Authors: Pimpan V. , Thothong P.
Published: June 2006

Graft copolymers of cassava starch and methyl methacrylate (MMA) were synthesized by free‐radical polymerization with benzoyl peroxide (BPO) as an initiator in an aqueous medium at 80°C. The formation of graft copolymers was confirmed by analysis of the obtained products with Fourier transform infrared spectroscopy and scanning electron microscopy. The effects of the amount of cassava starch, the amount of MMA monomer, the amount of BPO, and the reaction time on the grafting characteristics were studied. The optimum condition for grafting were obtained when 5 g of cassava starch, 5 g of MMA, 0.1 g of BPO, and a reaction time of 3 h were used. These condition provided a graft copolymer with 25.00% add‐on, 81.40% monomer conversion, 54.30% homopoly(methyl methacrylate) formed, 45.70% grafting efficiency, 37.20% grafting ratio, and 95.54% yield. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4083–4089, 2006
Effect of the processing methods on the performance of polylactide films: Thermocompression versus solvent casting
Authors: Rhim Jong‐Whan , Mohanty Amar K. , Singh Sher P. , Ng Perry K. W.
Published: June 2006

Polylactide (PLA) films were prepared by the thermocompression and solvent‐casting methods, and selected properties, such as the mechanical, water‐vapor‐barrier, thermal, and thermomechanical properties, were tested. The solvent‐cast films contained 13.7% solvent, which functioned as a plasticizer, as evidenced by the results of the measurements of dry matter and thermogravimetric analysis as well as dynamic mechanical analysis. The PLA films prepared by the thermocompression method were strong and brittle, with maximum tensile strength (σmax) and maximum elongation at break (ϵmax) values of 44.0 ± 2.2 MPa and 3.0 ± 0.1%, respectively; however, the solvent‐cast films were more ductile, with σmax and ϵmax values of 16.6 ± 1.0 MPa and 203.4 ± 20.8%, respectively. The water vapor permeability of the PLA films was lower than that of plastic films such as low‐density polyethylene and high‐density polyethylene but higher than that of commonly used biopolymer films. In addition, both types of tested PLA films were water‐resistant and not soluble in water. The thermocompressed films showed higher thermal stability than the solvent‐cast films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3736–3742, 2006
Synthesis, characterization, and application of new low‐cost ion exchangers
Authors: Kannan N. , Seenivasan R. K.
Published: June 2006

This paper represents a simple method for preparing and characterizing of low‐cost ion exchangers of sulfonated carbon prepared fromTerminalia Chebula‐Retz., (family–combretaceae) as a source of cheap plant material blended with phenol‐formaldehyde as a crosslinking agent. The prepared ion exchange resins (IERs) are characterized by infrared (IR) spectral and thermal studies. All the important physicochemical properties of the ion exchangers have been determined. The synthesized resins have cation exchange capacity upto 1.84 mmol g−1. The rational thermodynamic equilibrium constant (lnK) are calculated for H+and Zn2+exchanges on the resin having various amount of sulfonatedTerminalia ChebulaRetz. carbon (STCC). The thermodynamic parameters were calculated, and suitable explanations are given. It is concluded from the present study that PFR sample could be blended with 20% (w/w) of STCC, without affecting its physicochemical, spectral, and thermal properties. Hence blending with STCC will definitely lower the cost of the ion exchange resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4104–4113, 2006
Interfacially initiated microemulsion copolymerization: One‐stage preparation of poly(n‐butyl methacrylate)–poly(N‐vinyl pyrrolidone) core–shell nanoparticles
Authors: He Wei‐Dong , Zheng Cheng , Ye Fang‐Mao , Wang Yan‐Mei , Liu Wei‐Jun
Published: June 2006

Interfacially initiated microemulsion copolymerizations of n‐butyl methacrylate (BMA) and N‐vinyl pyrrolidone (NVP) by the redox initiation couple of benzoyl peroxide and ferrous sulfate were carried out with Tween 80 and n‐butanol as the surfactant and cosurfactant, respectively. Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy were recorded to analyze the chemical composition of the latex particles. Transmission electron microscopy was used to observe the particle morphology and dynamic light scattering to determine the particle size. The results demonstrated that interfacially initiated microemulsion polymerization prompted the copolymerization of the water‐soluble NVP monomer with the oil‐soluble BMA monomer to form core–shell nanoparticles. The influence of the surfactant concentration, BMA amount, and temperature on the particle size and polymerization rate was investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3751–3757, 2006
Differential adsorption of heavy metal ions by cotton stalk cation‐exchangers containing multiple functional groups
Authors: Nada A. M. A. , El‐Wakil N. A. , Hassan M. L. , Adel A. M.
Published: June 2006

Esterification of cotton stalks with chlorosulfonic acid, phosphorus oxychloride, and their mixture was carried out with the aim to prepare cation exchangers for the removal of heavy metal ions from industrial waste water. Elemental analysis, Fourier transform infrared (FTIR) analysis, and sodium ions binding capacity were used to prove the occurrence of the esterification. The efficiency of the prepared cation exchangers to remove some heavy metal ions (strontium, arsenic, copper, and nickel) at different metal ion concentration, pH, contact time, and temperature was studied. The results showed that cotton stalks that contain both phosphate and sulfonate groups (phosphosulfonated cotton stalks) showed higher adsorption of the different heavy metal ions than cotton stalks containing sulfonate or phosphate on a separate basis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4124–4132, 2006