bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenotypic and Genetic Heterogeneity in Congenital Generalized Lipodystrophy
Authors: Agarwal Anil K. , Simha Vinaya , Oral Elif Arioglu , Moran Stephanie A. , Gorden Phillip , O’Rahilly Stephen , Zaidi Zohra , Gurakan Figen , Arslanian Silva A. , Klar Aharon , Ricker Alyne , White Neil H. , Bindl Lutz , Herbst Karen , Kennel Kurt , Patel Shailesh B. , Al-Gazali Lihadh , Garg Abhimanyu 
Published: October 2003

Abstract
Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by near complete absence of adipose tissue from birth. Recently, mutations in 1-acylglycerol-3-phosphate O-acyltransferase 2 (AGPAT2) and Berardinelli-Seip congenital lipodystrophy 2 (BSCL2) genes were reported in pedigrees linked to chromosomes 9q34 and 11q13, respectively. There are limited data regarding phenotypic differences between the various subtypes of CGL. Furthermore, whether there are additional loci for CGL remains unknown. Therefore, we genotyped 45 pedigrees with CGL for AGPAT2 and BSCL2 loci and compared the phenotypes in the various subtypes. Twenty-six pedigrees harbored mutations, including seven novel variants, in the AGPAT2 gene, and 11 pedigrees harbored mutations in the BSCL2 gene, including five novel variants. Eight pedigrees had no substantial alterations in either gene. Of these, three informative pedigrees showed no linkage to markers spanning the AGPAT2 and BSCL2 loci, and in six of the affected subjects, the transcripts of AGPAT2 and BSCL2 were normal. All subtypes of CGL showed high prevalence of diabetes, hypertriglyceridemia, and acanthosis nigricans. However, patients with BSCL2 mutations had lower serum leptin levels, an earlier onset of diabetes, and higher prevalence of mild mental retardation compared with other subtypes. We conclude that besides AGPAT2 and BSCL2, there may be additional loci for CGL. The genetic heterogeneity in CGL patients is accompanied by phenotypic heterogeneity.
Polyethylene dispersions in bitumen: The effects of the polymer structural parameters
Authors: Yousefi Ali Akbar 
Published: October 2003

AbstractPolymer‐modified bitumens are very important to the transportation sector. Polyethylene is one of the most used polymers in bitumen modification. The effects of the structural parameters of polyethylene on its dispersion in bitumen and the performance of the resulting polymer‐modified bitumens were studied. With the addition of different polyethylenes to bitumen, the performance of bitumen at high temperatures increased as the polymer melt‐flow index (MFI) decreased. At low temperatures, the performance of bitumen decreased as the polyethylene MFI decreased. Furthermore, a decrease in the polyethylene MFI intensified its dispersion instability. At very low MFIs, the dispersions were unstable, even under the very high shear forces applied by a double mixer. Moreover, changes in the polyethylene MFI did not improve the dispersion stability at an elevated temperature (165°C). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3183–3190, 2003
Effect of stabilization on creep crack growth in high‐density polyethylene
Authors: Pinter G. , Lang R. W. 
Published: October 2003

AbstractPolyolefins, particularly polyethylene, are known to fail via crack initiation and crack propagation when exposed to multiaxial long‐term static stresses at elevated temperatures. Using concepts of linear elastic fracture mechanics, this article describes and discusses the effects of stabilization on the kinetics of creep crack growth (CCG) in high‐density polyethylene (PE‐HD) and the failure micromechanisms involved. As for the influence of stabilization, six PE‐HD formulations (two polymer types, each with three stabilizer systems) were investigated. CCG initiation times and CCG rates were determined at 60 and 80°C in distilled water as functions of the crack tip stress field characterized by the stress intensity factor. Although no influence of the stabilizer type was found in either polymer type for CCG initiation times and CCG rates at high crack speeds, significant effects of the added stabilizer type and concentration were detected for low CCG rates. The observed phenomena were explained in terms of local aging processes in the immediate vicinity of the crack tip, which were controlled by the presence and content of various stabilizers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3191–3207, 2003
Synthesis and characterization of poly(1,3‐thiazol‐2‐yl‐carbomoyl) methyl methacrylate: Its metal complexes and antimicrobial activity studies
Authors: Soykan Cengiz , Erol İbrahim , Kırbağ Sevda 
Published: October 2003

AbstractPoly(1,3‐thiazol‐2‐yl‐carbomoyl) methyl methacrylate [poly(TCMMA)] is prepared in dimethyl sulfoxide using 2,2′‐azobisisobutyronitrile as an initiator at 60°C. Poly(TCMMA) is characterized by IR and 1H‐NMR spectroscopic techniques. Cadmium(II), copper(II), and nickel(II) chelates of poly(TCMMA) were synthesized. An elemental analysis of the polychelates suggests a metal/ligand ratio of 1:2. The polychelates are further characterized by IR and magnetic susceptibility measurements. The thermal properties of the polymer and metal chelates are also discussed. The molecular weights of the poly(TCMMA) are determined by the gel permeation chromatography technique. The antimicrobial activities of the polymer and metal chelates are tested against Staphylococcus aureus COWAN I (bacteria), Escherichia coli ATCC 25922 (bacteria), Listeria monocytogenes SCOTTA (bacteria), Bacillus subtilis LMG (bacteria), Enterobacter aeroginosa CCM 2531 (bacteria), Klebsiela pneumania FMCS (bacteria), Candida albicans CCM 314 (Mayo yeast), and Saccharamyces cerevisiae UGA 102 (Mayo yeast). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3244–3251, 2003
Structure and properties of fully aromatic thermotropic liquid‐crystalline copolyesters containing m‐hydroxybenzoic acid units
Authors: Yerlikaya Zekeriya , Aksoy Serpil , Bayramli Erdal 
Published: October 2003

AbstractA series of fully aromatic copolyesters based on p‐acetoxybenzoic acid (p‐ABA), hydroquinone diacetate (HQDA), terephthalic acid (TPA), and m‐acetoxybenzoic acid (m‐ABA) were prepared by a modified melt‐polycondensation reaction. The copolyesters were prepared in two series in which series I is based on a two monomer system (p‐ABA/m‐ABA) and series II is based on a three monomer system (HQDA/TPA/m‐ABA). The effect of different linear structures and kink moiety on the properties of the copolyesters were investigated systematically. The copolyesters were characterized by differential scanning calorimetry, thermogravimetric analysis, 1H‐NMR, polarized optical microscopy, X‐ray diffraction, and intrinsic viscosity measurements. It was found that the copolyesters exhibited nematic liquid‐crystalline phases when the content of linear (p‐ABA or HQDA/TPA) units was over 67 mol %. The melting or flow‐transition temperatures were decreased with an increase of the content of kink m‐ABA units. The copolyesters that contained p‐ABA as linear units had a significantly higher degree of crystallinity compared to the copolyesters that contain HQDA/TPA as the linear units, implying a higher blockiness in the polymer chains as a result of the higher reactivity of the p‐ABA units in the p‐ABA/m‐ABA system. All the copolyesters had poor solubility except the copolyesters containing at least 40 mol % of m‐ABA, which were soluble in a dichloromethane/trifloroacetic acid (70:30 v/v) mixture. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3260–3269, 2003
Energy absorption in glass‐reinforced continuous strand mat composites
Authors: Jacob George C. , Starbuck J. Michael , Simunovic Srdan , Fellers John F. 
Published: October 2003

AbstractA unique test fixture was developed for determining the energy‐absorbing mechanisms in automotive composite material systems. The objective of the test method was to quantify the energy absorption and identify the failure mechanisms associated with the observed frond formation in progressive crush testing of composite tubes by testing less costly composite plates under progressive crush load conditions. Quasi‐static progressive crush tests were performed on glass/polyurethane continuous strand mat (CSM) composite plate specimens. The effect of various test parameters on energy absorption was evaluated by varying the following parameters during testing: the loading rate, profile radius, and profile constraint condition. The experimental data in conjunction with the test observations were used to develop analytical models for predicting the crashworthiness of automotive composite structures. The crushing process and the load‐deflection curves were similar to the progressive crushing of tubes. Modification of the basic specimen geometry was required when testing material systems that have low axial stiffness to prevent a global buckling mode. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3222–3232, 2003
Mechanical properties of an epoxy resin toughened by polyester
Authors: Cao Youming , Shao Yuefeng , Sun Jun , Lin Shang'An 
Published: October 2003

AbstractThe epoxy resins were toughened by 4–24 phr polyester with average molecular weight 1.9×104 g/mol in this investigation. The mechanical properties were examined and dynamic mechanics analyses were performed for the epoxy resins before and after the modification. The toughening mechanism of polyester to epoxy resin is discussed in light of the scanning electronic microscopy observation of the fracture surfaces. The results showed that the impact strength and tensile strength of the modified epoxy resin were remarkably greater than those of the unmodified cured epoxy resin. The most suitable composition for the modified epoxy resin was the addition of 16 phr polyester, which led to 138 and 46% increments in the impact strength and the tensile strength, respectively. And the mechanical properties depended greatly on the congregating state of polyester added. The polyester dispersing in the epoxy matrix was amorphous when its addition was less than or equal to 12 phr, and was sphere crystals when the addition was over 16 phr. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3384–3389, 2003
Influence of previous annealing on first stage of degradation of blends of low‐density polyethylene and Mater‐Bi AF05H aged in soil: Comparative thermal analysis study
Authors: Vallés‐Lluch A. , Contat‐Rodrigo L. , Ribes‐Greus A. 
Published: October 2003

AbstractSamples of low‐density polyethylene (LDPE) filled with a commercial biodegradable material (Mater‐Bi AF05H) were subjected to an accelerated soil burial test in a culture oven. In addition, another series of these blends was subjected to thermal treatment and afterward buried in soil under the same conditions. Comparative studies of the changes in the thermal stability and the structural and morphological properties of the samples were carried out by means of differential scanning calorimetry, dynamic mechanical thermal analysis, and thermogravimetric analysis. The morphological properties under study were the melting temperature, the crystalline content, and the lamellar thickness distribution. The αI relaxation zone of the mechanical spectra was characterized in terms of tan δ, whereas the αII and relaxation zones were characterized in terms of E″ according to the Fuoss–Kirkwood equation and with the help of a deconvolution method. Finally, the kinetics of each thermodegradation process was studied using the Broido integral method. The Mater‐Bi hindered the uniform growth of crystallites in PE and facilitate molecular motions, but the thermal treatment seemed to rearrange the crystallites in the crystalline phase of PE and promote segregation of the crystallite sizes. These molecular reorganizations affected the degradation process so that the degradation of the polymeric matrix seemed to be obstructed by the annealing during the first 120 days of aging in soil and only the Mater‐Bi degradation could be observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3359–3373, 2003
Studies on novel binary accelerator system in sulfur vulcanization of natural rubber
Authors: Marykutty C. V. , Mathew G. , Mathew E. J. , Thomas Sabu 
Published: October 2003

AbstractThe synergistic activity of binary accelerator systems in rubber vulcanization is well known. Binary accelerator systems are being widely used in industry and are becoming increasingly popular because of the fact that such mixed systems can effectively prevent prevulcanization, permit the vulcanization to be carried out at a lower temperature in a shorter time, and produce a vulcanizate with superior mechanical properties compared to those of a stock cured with a single accelerator. Thiourea and its derivatives are important secondary accelerators in this context. It is suggested that thiourea containing binary accelerator systems cause rubber vulcanization to proceed by a nucleophilic reaction mechanism. In the present study 1‐phenyl‐5‐ortho, ‐meta, and ‐para‐tolyl derivatives of 2,4‐dithiobiurets, which are more nucleophilic than thiourea and vary in their nucleophilic reactivity, are used as secondary accelerators along with 2‐morpholinothiobenzothiazole in the vulcanization of natural rubber. The results show an appreciable reduction in the cure time for the mixes containing the dithiobiurets compared to the reference mix. These results are indicative of a nucleophilic reaction mechanism in the vulcanization reaction under consideration. These vulcanizates also demonstrate comparatively better tensile properties and good retention of these properties after aging. An attempt is also made to correlate the variation in physical properties to chemical crosslink formation in the various vulcanizates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3173–3182, 2003
Morphology and stress relaxation in oriented polyolefin shrink films
Authors: Bobovitch Arthur , Gutman Emmanuel , Henning Sven , Michler Goerg H. 
Published: October 2003

AbstractMorphology and stress relaxation of oriented polyolefin films has been studied. The influence of orientation on morphology of the films has been investigated using X‐ray, DSC, and TEM. The relaxation time spectrum of oriented films has been investigated. It was shown that relaxation time spectrum of composite film can be predicted if one knows the relaxation time spectrum of each component in the film. An influence of irradiation on relaxation behavior of polyethylene film was shown as well. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3424–3429, 2003
Preparation and properties of cellulose/chitin blend fiber
Authors: Pang Feng‐Jian , He Chun‐Ju , Wang Qing‐Rui 
Published: October 2003

AbstractThe blend solution of cellulose xanthate with chitin xanthate has excellent filtering property as an ordinary cellulose viscose. The SEM photos show that the fiber surface becomes coarse with increasing chitin content. The X‐ray diffraction shows that the addition of chitin interferes with the crystallization of cellulose. The dry and wet strength and density of blend fibers decrease with increasing chitin content. The hygroscopicity of the blend staples decreases with increasing chitin content, and there exists a minimum at 3.85% chitin mass percent, while the accessibility shows the same tendency. The fiber prepared has effective bacteriostatic effects on Staphylococcus aureus, Escherchia coli, etc., and the bacteriostastic rate increases with increasing chitin content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3430–3436, 2003
Kinetics and thermodynamics of hydrolytic depolymerization of poly(ethylene terephthalate) at high pressure and temperature
Authors: Mishra S. , Zope V. S. , Goje A. S. 
Published: October 2003

AbstractHydrolytic depolymerization of PET (polyethylene terephthalate) waste in excess of water was studied using a 0.5‐L stirred high‐pressure autoclave at temperatures of 100, 150, 200, and 250°C and at 200, 300, 400, 500, 700, and 800 psi (pounds per square inch) pressure. Velocity constants of hydrolysis were calculated from the experimental data obtained. Maximum depolymerization (91.38%) of PET into monomer was obtained at 250°C and 800 psi. pressure. However, the maximum rate of reaction was recorded at 200°C and 500 psi temperature and pressure, respectively. The energy of activation and frequency factor were calculated, as 64.13 KJ/g mol and 7.336 × 104 min−1, respectively, for higher pressure and temperature conditions. It was also reported that the hydrolytic depolymerization is first order with the velocity constant 1.773 × 10−2 min−1 at 250°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3305–3309, 2003
Glycolytic aminolysis of poly(ethylene terephthalate) waste for recovery of value‐added comonomer at atmospheric pressure
Authors: Goje A. S. , Thakur S. A. , Patil Tushar M. , Mishra S. 
Published: October 2003

AbstractReaction of poly(ethylene terephthalate) waste (PETW) powder with ethylene glycol (EG) using 0.003 mol lead acetate as a catalyst was carried out in a batch reactor at 470 K under atmospheric pressure. Reactions were undertaken with various particle sizes ranging from 50 to 512.5 μm and reaction times ranging from 10 to 60 min at 10‐min intervals. A low molecular weight product of PETW was obtained using this reaction. Then hydrazine monohydrate, chlorobenzene, and cyclohexylamine (CHA) were introduced to convert the low molecular weight product of PETW into terephthalohydrazide (TPHD). To increase the PETW conversion rate, an external catalyst (lead acetate) was introduced during the reaction. The reaction product was deposited onto the surface of unreacted PETW that was removed from the surface by introducing dimethyl sulfoxide. To accelerate the reaction rate CHA was introduced during the second stage of reaction, which has industrial significance. Depolymerization of PETW was proportional to the reaction time and inversely proportional to the particle size of PETW. Analyses of value‐added products (TPHD and EG) as well as PETW were undertaken. A kinetic model was developed and experimental data were simulated consistent with the model. A thermodynamic study was undertaken because this is required during the transfer of laboratory data through the pilot plant for commercialization. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3437–3444, 2003
Miscibility in crystalline polymer blends: Isotactic polypropylene and linear low‐density polyethylene
Authors: Gorrasi Giuliana , Pucciariello Rachele , Villani Vincenzo , Vittoria Vittoria , Belviso Sandra 
Published: October 2003

AbstractThe phase behavior and the crystallization kinetics of blends composed of isotactic polypropylene (iPP) and linear low‐density polyethylene (LLDPE) were investigated by differential scanning calorimetry. The phase behavior indicates the formation of separate crystals of iPP and LLDPE at each investigated blend composition. The crystallization trace reveals that iPP crystallizes in its normal range of temperatures (i.e., at temperatures higher than that of LLDPE), when its content in the blend is higher than 25% by weight. In the blend whose iPP content is as high as 25%, at least a portion of iPP crystallizes at temperatures lower than that of LLDPE. This behavior has been proposed by Bassett to be attributed to a change in the kind of nucleation from heterogeneous to homogeneous. From the Avrami analysis of the isothermal crystallization of iPP in the presence of molten LLDPE, n values close to 2 are always obtained. According to our previously proposed interpretation of the Avrami coefficient, it can be related to the crystallite fractal dimension, through d = n + 1, which gives values close to 3, according to the spherulitic observed morphology. The kinetics parameter, i.e., the half‐time of crystallization, and the kinetic constant k show that a decrease in the overall rate of crystallization of iPP occurs on blending. Optical microscopy photographs, taken during the cooling of the samples from the melt, confirm the above results and show increasingly less resolved spherulite texture on increasing LLDPE content in the blend. The diffusion parameters evaluated for the neat polymers and for the blends in dichloromethane, which give information on the miscibility in the amorphous state, show that the diffusional behavior of the blends is governed by iPP, suggesting a two‐phase amorphous state. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3338–3346, 2003
Synthesis and characterization of proton‐conducting copolymers on the basis of vinylpyrrolidone and acrylamido sulfonic acid
Authors: Bozkurt A. , Ekinci Ö. , Meyer W. H. 
Published: October 2003

AbstractFree‐radical copolymerizations of 1‐vinyl‐2‐pyrrolidone with 2‐acrylamido‐2‐methyl propane sulfonic acid at different feed ratios were investigated. The copolymers were characterized by 1H‐NMR, 13C‐NMR, and FTIR. The copolymer composition was determined from the elemental analysis. The molecular weights (Mw, Mn) and dispersities of the copolymers were determined by gel permeation chromatography. Thermogravimetric analysis indicated that copolymers are stable at least up to 200°C. Temperature dependency of the alternating current (ac) conductivities was investigated by means of impedance spectroscopy. The direct current (dc) conductivities of the samples were obtained from the ac conductivity data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3347–3353, 2003
Contribution of connexin26 to electrical feedback inhibition in the turtle retina
Authors: Pottek Mark , Hoppenstedt Werner , Janssen‐Bienhold Ulrike , Schultz Konrad , Perlman Ido , Weiler Reto 
Published: October 2003

AbstractThe first synaptic integration in the neuronal cascade of vision in vertebrates includes a feedback from horizontal cells to cones by a mechanism yet not fully understood. Recent observations in teleosts suggested an electrical feedback mechanism mediated by connexin26 (Cx26) hemichannels at the terminal dendrites of horizontal cells. By using reverse transcription‐polymerase chain reaction and immunoblotting from retinal homogenate, we detected Cx26 mRNA transcripts in the turtle retina and demonstrated that they were translated into protein. Cx26 immunoreactivity was especially prominent in the outer plexiform layer. Subcellularly, immunoreactivity was located mainly between horizontal cell axon terminals and in horizontal cell dendrites forming the lateral elements at the ribbon synaptic complex of the cone pedicle. The label was confined to the horizontal cell membrane flanking the ribbon and was not found on the opposing photoreceptor membrane. No gap junctions at this location are known, so immunosignaling suggested the presence of hemichannels. Their relevance to the feedback mechanism was investigated by intracellular recordings from horizontal cells during application of the hemichannel blocker carbenoxolone. Carbenoxolone hyperpolarized the dark membrane potential by about 25 mV, decreased the amplitudes of responses to full‐field light flashes, and suppressed the feedback‐induced depolarizing inflexion in the response profile. These physiological findings are compatible with the involvement of hemichannels in the feedback between horizontal cells and cones and support the anatomical findings. Together, these data suggest the presence of an electrical feedback mechanism in the turtle retina, which therefore might be a common mechanism at the first visual synapse in vertebrates. J. Comp. Neurol. 466:468–477, 2003. © 2003 Wiley‐Liss, Inc.