bluuebunny/crossref_metadata_2025 huggingface dataset:
Genome‐wide scan for linkage to schizophrenia in a Spanish‐origin cohort from Costa Rica
Authors: DeLisi Lynn E. , Mesen Andrea , Rodriguez Carlos , Bertheau Arturo , LaPrade Beatrice , Llach Michelle , Riondet Silvina , Razi Kamran , Relja Margaret , Byerley William , Sherrington Robin
Published: October 2002

Genetic isolates have been useful cohorts in which to search for genes underlying disorders of unknown pathology. One such cohort is thought to exist in the Central Valley of Costa Rica surrounding the city of San Jose. Previous investigators identified a rare dominant gene for hereditary deafness in this population, and a suggestive linkage of severe bipolar psychosis has been reported in another study. Ninety‐nine families with at least one pair of siblings affected with schizophrenia or a schizophrenia‐spectrum diagnosis had clinical evaluations and DNA collected for genotyping. The Marshfield Medical Research Foundation (NHLBI) Mammalian Genotyping Service performed all genotyping using 404 short‐tandem repeat polymorphic markers (STRPs) spaced on average 10 cM apart. Data were analyzed using the nonparametric program, GeneHunterPlus. The population structure was investigated using the STRUCT program. No region was found with genome‐wide significance for linkage. Using a phenotype of schizophrenia plus schizoaffective disorder, the highest maximum likelihood score (MLS) observed was 1.78 (P < 0.004) at 176.6 cM from pter on chromosome 5q, an area previously implicated by some other groups. In addition, five regions on chromosomes 1p, 2p, 2q, 14p, and 8p had MLSs above 1.0. All other regions produced scores below 1.0. Population genetic analysis reveals no evidence for population substructure, for admixture with other populations, such as Amerindians, or for inbreeding in the parental generation. The latter casts some doubt on this population being an isolate, although there was evidence of inbreeding among the offspring. © 2002 Wiley‐Liss, Inc.
Further evidence for a fourth gene causing X‐linked pure spastic paraplegia
Authors: Starling A. , Rocco P. , Cambi F. , Hobson G.M. , Passos Bueno M.R. , Zatz M.
Published: October 2002

X‐linked hereditary spastic paraplegias (HSPs) present with two distinct phenotypes: pure and complicated. The pure form is characterized by slowly progressive weakness and spasticity of the lower limbs, whereas the complicated forms have additional features (optic neuropathy, retinopathy, extrapyramidal disturbance, dementia, epilepsy, ataxia, ichthyosis, mental retardation, and deafness). Three X‐linked loci have been identified for the complicated HSP, while mutations in the proteolipid gene (PLP) (locus SPG2) were implicated in both pure and complicated forms. The absence of identified mutations in the PLP gene in families with both complicated and pure HSP, linked to the SPG2 locus, suggests the existence of another gene in close proximity. We had previously reported a large pedigree with an X‐linked form of pure HSP affecting 24 males [Zatz et al., 1976: J Med Genet 13:217–222]. Here, we present the results of linkage analysis in 19 members of this Brazilian family with markers in or near the PLP locus. Positive LOD scores were obtained with markers at the PLP locus (Zmax = 2.41 at Theta = 0); however, no mutation was found in the coding region of PLP, the intron‐exon boundaries, or part of the promoter region. The possibility of a duplication of the PLP gene was also excluded. These results suggest either that there is another X‐linked gene in close proximity to the PLP gene or that a novel mutation in the noncoding regions of the PLP gene may cause the disease in this family. © 2002 Wiley‐Liss, Inc.
No evidence for a susceptibility locus for idiopathic generalized epilepsy on chromosome 18q21.1
Authors: Sander Thomas , Windemuth Christine , Schulz Herbert , Saar Kathrin , Gennaro Elena , Bianchi Amedeo , Zara Federico , Bulteau Christine , Kaminska Anna , Ville Dorothée , Cieuta Cécile , Prud'homme Jean‐François , Dulac Olivier , Bate Louise , Gardiner R. Mark , de Haan Gerrit‐Jan , Janssen Guus A.M.A.J. , Witte Jorine , Halley Dicky J.J. , Lindhout Dick , Wienker Thomas F. , Janz Dieter ,   European Consortium on the Genetics of Idiopathic Generalized Epilepsy
Published: October 2002

A recent genome‐wide scan showed strong evidence for a major locus for common syndromes of idiopathic generalized epilepsy (IGE) at the marker D18S474 on chromosome 18q21.1 (LOD score 4.5/5.2 multipoint/two‐point). The present replication study tested the presence of an IGE locus in the chromosomal region 18q21.1. Our linkage study included 130 multiplex families of probands with common IGE syndromes. Eleven microsatellite polymorphisms encompassing a candidate region of 30 cM on either side of the marker D18S474 were genotyped. The two‐point homogeneity LOD score for D18S474 showed strong evidence against linkage at the original linkage peak (Z = −18.86 at θm = f = 0.05), assuming a recessive mode of inheritance with 50% penetrance. Multipoint parametric heterogeneity LOD scores < −2 were obtained along the candidate region when proportions of linked families greater than 35% were assumed under recessive inheritance. Furthermore, non‐parametric multipoint linkage analyses showed no hint of linkage throughout the candidate region (P > 0.19). Accordingly, we failed to support evidence for a major IGE locus in the chromosomal region 18p11–18q23. If there is a susceptibility locus for IGE in this region then the size of the effect or the proportion of linked families is too small to detect linkage in the investigated family sample. © 2002 Wiley‐Liss, Inc.
Serpens endocrania symmetrica (SES): A new term and a possible clue for identifying intrathoracic disease in skeletal populations
Authors: Hershkovitz Israel , Greenwald Charles M. , Latimer Bruce , Jellema Lyman M. , Wish‐Baratz Susanne , Eshed Vered , Dutour Olivier , Rothschild Bruce M.
Published: October 2002

This paper describes a phenomenon in the endocranial plate, which we have termed “serpens endocrania symmetrica” (SES), and discusses its value as a diagnostic tool. The affected discolored bone area exhibits disruption of the endocranial surface, lending it a maze‐like appearance. Histological sections demonstrate that the process is limited to the most superficial portion of the endocranium, with no diploic and ectocranial involvement (sinus areas excepted). Adult skulls (n = 1,884) from the Hamann‐Todd collection (HTH), housed at the Cleveland Museum of Natural History, were utilized for the present study. SES was recognized in 32 of the 1,884 skulls studied (1.7%). The frequency of SES among individuals reported to have died from tuberculosis (TB) was 4.4%. The rate of SES in the non‐TB sample was only 0.53%. The locations were as follows: limited to sinus area, 28.1%; calvarium (excluding the sinuses), 46.9%; sinus + calvarium, 25.0%. SES was bilateral in 90.9% of cases. Twenty‐five of the 32 individuals (78.1%) with SES in the HTH collection had tuberculosis specifically listed as the cause of death. Six of the other 7 individuals had infections other than TB. In 29 of the 32 individuals with SES, infection involved structures within the thorax. As SES was also associated with another osteological phenomenon known to represent pulmonary disease, i.e., hypertrophic osteoarthropathy (HOA; 68.0% of SES individuals also had HOA), SES may be of diagnostic value in paleopathology for the recognition of intrathoracic disease, and perhaps tuberculosis. Am J Phys Anthropol 118:201–216, 2002. © 2002 Wiley‐Liss, Inc.
Brief communication: Haplogroup X confirmed in prehistoric North America
Authors: Malhi Ripan S. , Smith David Glenn
Published: October 2002

Haplogroup X represents approximately 3% of all modern Native North American mitochondrial lineages. Using RFLP and hypervariable segment I (HVSI) sequence analyses, we identified a prehistoric individual radiocarbon dated to 1,340 ± 40 years BP that is a member of haplogroup X, found near the Columbia River in Vantage, Washington. The presence of haplogroup X in prehistoric North America, along with recent findings of haplogroup X in southern Siberians, confirms the hypothesis that haplogroup X is a founding lineage. Am J Phys Anthropol 119:84–86, 2002. © 2002 Wiley‐Liss, Inc.
Sickle cell disease: The neurological complications
Authors: Prengler Mara , Pavlakis Steven G. , Prohovnik Isak , Adams Robert J.
Published: October 2002

The genetic cause of sickle cell disease has been known for decades, yet the reasons for its clinical variability are not fully understood. The neurological complications result from one point mutation that causes vasculopathy of both large and small vessels. Anemia and the resultant cerebral hyperemia produce conditions of hemodynamic insufficiency. Sickled cells adhere to the endothelium, contributing to a cascade of activated inflammatory cells and clotting factors, which result in a nidus for thrombus formation. Because the cerebrovascular reserve becomes exhausted, the capacity for compensatory cerebral mechanisms is severely limited. There is evidence of small‐vessel sludging, and a relative deficiency of nitric oxide in these vessels further reduces compensatory vasodilatation. Both clinical strokes and silent infarcts occur, affecting motor and cognitive function. New data suggest that, in addition to sickle cell disease, other factors, both environmental (eg, hypoxia and inflammation) and genetic (eg, mutations resulting in thrombogenesis), may contribute to a patient's stroke risk. The stroke risk is polygenic, and sickle cell disease can be considered a model for all cerebrovascular disease. This complex disease underscores the potential intellectual and practical distance between the determination of molecular genetics and effective clinical application and therapeutics.
Interaction of cognitive aging and memory deficits related to epilepsy surgery
Authors: Helmstaedter Christoph , Reuber Markus , Elger Christian C. E.
Published: October 2002

Temporal lobe epilepsy surgery can cause significant memory impairment. This study was intended to examine whether surgery also could affect prognosis of memory in older age. Age regression of verbal memory was examined in 187 patients (before and 1 year after left temporal lobe surgery) and 264 healthy controls. Eighty patients underwent selective amygdalohippocampectomy, and 107 patients underwent anterior two‐thirds temporal lobectomy. Amygdalohippocampectomy patients had mesiotemporal epilepsy; anterior two‐thirds temporal lobectomy patients had more extramesial or diffuse seizure onset zones. Memory was assessed by word list learning for its more mesial (consolidation/retrieval) and more neocortical (learning) aspects. Patients showed significant preoperative memory impairment. Independent of seizure outcome and surgical approach, surgery had significant negative effects on learning and consolidation/retrieval. In the amygdalohippocampectomy group, preoperative and postoperative age regressions of learning and consolidation/retrieval were not different from those of controls. In the anterior two‐thirds temporal lobectomy group, age regression of verbal learning became steeper after surgery, and consolidation/retrieval was negatively correlated with older age and later onset of epilepsy even before surgery. The data confirm that age regression of verbal memory in left temporal lobe epilepsy is similar to that in healthy controls. Both left anterior two‐thirds temporal lobectomy and amygdalohippocampectomy worsen verbal learning and memory and bring patients closer to cognitive disability. Particularly in anterior two‐thirds temporal lobectomy patients, surgery and reduced capacities for compensation cause acceleration of lifetime memory decline. The results support earlier and tailored epilepsy surgery and suggest that memory prognosis in older age should be considered if more extensive temporal resections would be inevitable.
The effects of alkaline earth dehydroabietate on the crystallization process of polypropylene
Authors: Li Chun‐Cheng , Zhang Dong , Li Zhen‐Yi
Published: October 2002

In this article, the influence of alkaline earth dehydroabietates, which were prepared from Na‐dehydroabietate, on crystallization of polypropylene (PP) from the melt state was studied by differential scanning calorimetry and polarization microscopy. It was found that magnesium dehydroabietate could improve mechanical properties and crystallization temperatures of PP and also decrease the size of spherulites. Kinetic analysis of PP isothermal crystallization showed that magnesium dehydroabietate decreased the fold surface energy of the developing crystals of PP and promoted the nucleation and crystallization of PP. However, calcium dehydroabietate increased the fold surface energy of the developing crystals of PP, but had no nucleation effect on PP. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2644–2651, 2002
Investigation of loading and release in PVA‐based hydrogels
Authors: Ruiz J. , Mantecón A. , Cádiz V.
Published: October 2002

We used Methylene Blue (MB) and Methyl Orange (MO) as model drugs to investigate the controlled release behavior of hydrogels from poly(vinyl alcohol) crosslinked with ethylenediaminetetraacetic dianhydride. The cationic or anionic character of these compounds and the molecular weight between crosslinks of the hydrogel and the concentration of ionizable groups in the hydrogel greatly affected the loading and release of the drugs. MB loading was favored, therefore, by a higher content of negative charges in the hydrogel, although this implied a greater degree of crosslinking and, therefore, a lower mesh size. On the other hand, the overall loading of negative MO, favored by a higher mesh size, was very low because of unfavorable interactions with the electrolyte charges. Release studies showed that one of the parameters that most affected the drug release behavior of these hydrogels was the pH of the solution. MB and MO were not completely released, even at pH 1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1644– 1651, 2002.
The leaching kinetics of acetone in an acetone‐polyurethane adhesive waste
Authors: Font R. , Sabater M. C. , Martínez M. A.
Published: October 2002

This work consists of the study of the extraction of solvent (acetone) from a polymeric (polyurethane) substrate during a leaching process. Total organic carbon (T.O.C.) is the main contaminant parameter in the leaching of these systems due to the solution of the acetone which is practically totally extracted from the polymeric system. During the leaching process, the water (polar) diffuses across the holes formed between the chains of polyurethane reacting at the same time with the isocyanate groups at the end of the chains, causing the reticulation or crosslinking of the polymer. On the basis of the experimental results, the amount of acetone diffused versus time in plane sheet systems was studied. A diffusion model based on the Fickian law was developed considering two stages. In the first stage, the water diffuses into the system across the polyurethane chains causing the reticulation of the polymer and dissolving the acetone. In the second stage, the diffusion of acetone in water, which occupies the holes or spaces between the reticulated polymer, takes place. The diffusion kinetics in these kinds of systems are similar to the diffusion kinetics in a rigid solid, considering an effective diffusivity of the acetone through the system. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1945–1955, 2002
Curing and combustion properties of a PU‐coating system with UV‐reactive phosphazene
Authors: Huang Woei‐Kae , Chen Kwei‐Ju , Yeh Jen‐Taut , Chen Kan‐Nan
Published: October 2002

A UV‐curable polyurethane (PU)‐coating system containing phosphorus is formulated by the combination of photoinitiator, PU acrylate oligomer, and UV‐reactive phosphazene monomer. PU acrylate oligomer is prepared by the addition of 2‐hydroxyethylmethacrylate (HEMA) to NCO‐terminated PU prepolymer. UV‐reactive phosphazene monomer is derived from the HEMA substitution reaction to hexachlorocyclotriphosphazene (NPCl2)3. The curing reaction of this PU‐coating system is carried out by UV irradiation. The resultant UV‐cured PU‐coated films demonstrated better performance properties than those of original UV‐cured PU acrylate (UV‐PU) without UV‐reactive phosphazene monomer. Furthermore, their thermal properties are investigated by a thermogravimetric analyzer and a dynamic mechanical thermal analyzer, respectively. The combustion behaviors of these UV‐cured PU‐coated films are evaluated by the measurements of a limiting oxygen index and a cone calorimeter. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1980–1991, 2002
Surface modification of poly‐L‐lactide by photografting of hydrophilic polymers towards improving its hydrophilicity
Authors: Ma Zuwei , Gao Changyou , Yuan Jun , Ji Jian , Gong Yihong , Shen Jiacong
Published: October 2002

Poly‐L‐lactide (PLLA) has been used to prepare scaffolds to guide tissue regeneration in tissue engineering research. However, one of the limitations to the use of PLLA as an ideal biomaterial is its high hydrophobicity. To improve the hydrophilicity of PLLA, hydrophilic polymers were grafted onto PLLA membrane surfaces through the combination of photooxidization in hydrogen peroxide and subsequent ultraviolet (UV)‐induced grafting copolymerization in the monomer solution. Three kinds of modified PLLA membranes (i.e., PLLA‐g‐polyhydroxyethyl methacrylate, PLLA‐g‐polyacrylamide, and PLLA‐g‐polymethacrylic acid) were obtained, resulting in the more wettable PLLA membranes. The occurrence of the grafting polymerization was confirmed by attenuated total reflectance infrared spectroscopy (ATR‐IR) and X‐ray photoelectron spectroscopy (XPS) analysis. Surface morphology of the modified PLLA membranes was studied by scan electronic microscopy (SEM). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2163–2171, 2002
The conductivity behavior of multi‐component epoxy, metal particle, carbon black, carbon fibril composites
Authors: Jia W. , Tchoudakov R. , Joseph R. , Narkis M. , Siegmann A.
Published: October 2002

Following the previous studies of epoxy/silver conductive composites, a detailed investigation of the influence of ethylene glycol on the resulting resistivity of various composites was carried out. Ethylene glycol was found to have a catalytic effect on the curing process of the epoxy resin, verified by differential scanning calorimetry studies. The accelerated curing process diminishes settling of the metal particles and therefore results in better and more uniform conductivities. High temperature curing of the composites was found to have a similar effect on the conductivity. The conductivity behavior of some other composites, such as epoxy/nickel, epoxy/nickel/carbon fibrils, and epoxy/carbon black/carbon fibrils, were also studied. The structure–property relations were better understood through scanning electron microscopy observations. Silver and nickel particles were found to perform differently in the cured epoxy, showing different percolation concentrations and conductivity levels. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1706–1713, 2002
On the thermal degradation of poly(styrene sulfones). VII. Evaluations of poly(styrene sulfone) thermal stability using invariant kinetic parameters
Authors: Yang Mu‐Hoe
Published: October 2002

The thermal degradation behavior of poly(styrene sulfone) was investigated by thermogravimetric analysis (TGA) measurement. This study described its thermal stability by applying the invariant kinetic parameter (IKP) method. The thermogravimetric and differential thermogravimetric analyses of different compositions of poly(styrene sulfones) were carried out over the temperature range 100–500°C under nitrogen. The kinetic parameters (preexponential factor and activation energy) of thermal decomposition of poly(styrene sulfone) can be obtained by dynamic measurement of TGA. The IKP method assumes that the kinetic parameters are independent of the experimental conditions. These parameters are computed without any hypothesis on the form of the kinetic degradation function. Invariant activation energies of the degradation of poly(styrene sulfone) show that the thermal stability decreases as the SO2 content of poly(styrene sulfone) increases due to the thermal instability of the CS bond. The relation equation, Eainv = 237.0 − 290.5XSO2, where XSO2 is the molecular fraction of SO2, was obtained to describe the effect of sulfur dioxide on the thermal stability of poly(styrene sulfone). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1698–1705, 2002
Radiation effects on HDPE/EVA blends
Authors: Dalai Siqin , Wenxiu Chen
Published: October 2002

In this article, we discuss the radiation effects of high‐density polyethylene (HDPE)/ethylene–vinyl acetate (EVA) copolymer blends. In comparison with the low‐density polyethylene/EVA blends, the EVA content in the HDPE/EVA blends had a lower enhancement effect on radiation crosslinking by γ‐ray irradiation in air. The phenomenon is discussed with the compatibility, morphology, and thermal properties of HDPE/EVA blends. The HDPE/EVA blends were partly compatible in the amorphous region, and radiation crosslinking of the HDPE/EVA blend was less significant, although increasing the amorphous region's content of the HDPE/EVA blends and the vinyl acetate content of EVA were beneficial to radiation crosslinking. The good compatibility was a prerequisite for the enhancement effect of EVA on the radiation crosslinking of the polyethylene/EVA copolymer. The radiation crosslinking and the degradation mechanism of HDPE/EVA blends were examined quantitatively by a novel method, the step analysis process of irradiated HDPE/EVA blends with a thermal gravimetric analysis technique. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 553–558, 2002
Kinetics of polymerization and particle stabilization mechanism on dispersion copolymerization of styrene and divinylbenzene
Authors: Zhang Hong Tao , Huang Jin Xia , Jiang Bing Bing
Published: October 2002

Monodisperse highly crosslinked microspheres were prepared by dispersion copolymerization of styrene and divinylbenzene in an ethanol/water medium using poly(N‐vinylpyrrolidone) (PVP) as the stabilizer. The locus of polymerization and growth of particles were investigated. The polymerization kinetics, average particle diameter (Dn), polydispersity index (PDI), and numbers of particles (Np) were presented. When the initial styrene concentration is below 20%, the results indicate that the polymerization occurs in the particles, and the particles grow to their final size by the diffusion of monomer and oligomer into the existing particles. The polymerization rate can be described by the equation Rp = k[l]0.87 ([St]1.91 + [DVB]0.09) (1 + [PVP]0.01) exp(− 45.35/RT). The data from infrared spectroscopy demonstrated that the graft stabilizer was present. The dissolution experiments show that the crosslinking reaction occurred irregularly in batch dispersion polymerization. Using the postaddition approach, up to 3% divenylbenzene (DVB) was successfully incorporated in the synthesis of coagulum‐free substance, and monodisperse crosslinked 5 μ m microspheres with a superior resistance to solvents have been prepared. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2230–2238, 2002
Influence of synergists: The influence of hydroperoxide decomposers on phenolic inhibitors consumption in oxidized polypropylene
Authors: Shanina E. L. , Zaikov G. E. , Fazlieva L. K. , Bukharov S. V. , Mukmeneva N. A.
Published: October 2002

The influence of sulphur‐ and phosphorum‐containing substances (hydroperoxide decomposers) on the kinetics of the consumption of two phenolic antioxidants in polypropylene (PP) was studied. The induction periods of PP autoxidation at 130°C were measured in the presence of inhibiting compositions that consisted of phenolic inhibitors and decomposers of hydroperoxide. Obtained results indicated that the influence of the hydroperoxide decomposer became significant when the concentration of the phenolic antioxidant became close to critical value. It also was shown that the efficiency of the hydroperoxide decomposer significantly depended on the mechanism of the transformation of the phenolic inhibitor; and first of all on the nature of its transformation products. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2239–2243, 2002
Synthesis and investigation of oligosiloxanes containing γ‐trimethylsiloxy‐propyl or γ‐hydroxy‐propyl groups
Authors: Zhu Qingzeng , Feng Shengyu , Chen Jianhua
Published: October 2002

Oligosiloxanes having different distributions of SiH groups were prepared, and the addition of SiH bonds to CC double bounds of trimethyl(2‐propenyloxy)silane was utilized to obtain oligosiloxanes having different distributions of γ‐trimethylsiloxy‐propyl or γ‐hydroxy‐propyl groups as substituents. The oligosiloxanes were characterized by IR and 1H‐NMR spectroscopy. Viscosity was studied to investigate the effects of the substituents. Differential scanning calorimetry (DSC) was used to investigate the thermal behaviour of these oligosiloxanes. It was found that they are completely amorphous materials and, hence, show only a glass transition. We found that the viscosities and glass transition temperatures of these materials increased with the increasing of the number of substituents. Hydrogen bonds have a considerable influence on the increase of the viscosities and glass transition temperatures of oligosiloxanes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2431–2435, 2002
Controlled release of biocides in solid wood. II. Efficacy against Trametes versicolor and Gloeophyllum trabeum wood decay fungi
Authors: Liu Y. , Laks P. , Heiden P.
Published: October 2002

Biocide‐containing nanoparticles were suspended in water to prepare wood treating suspensions able to deliver up to 0.8 kg biocide/m3 of wood. The nanoparticle preparation method was versatile, and three fungicides (tebuconazole, chlorothalonil, and KATHON 930) and one insecticide (chlorpyrifos) were incorporated into the nanoparticles with little customization of the preparative method. Greater customization was required when the polymer matrix was changed, but the method was generally robust; nanoparticles could be prepared from several different polymers, copolymers, and polymer blends. The median nanoparticle size increased as the matrix hydrophobicity increased. Nanoparticles were quantitatively delivered into birch and southern yellow pine (SYP) at low suspension loadings, but the delivery efficiency decreased with increased suspension loading and with increased matrix hydrophobicity. The delivery efficiency was also less for birch than for SYP. Undelivered nanoparticles were found to have undergone aggregation. Greater aggregation occurred in the more hydrophobic formulations than in the hydrophilic formulations. High biological efficacy was found for all the biocides tested. Nanoparticle‐treated birch was exposed to Trametes versicolor for 55 days and some protection was afforded, even at biocide loading levels of only 0.1 kg/m3. At the highest loadings (∼0.6 kg/m3) the weight loss after exposure to T. versicolor was generally ∼10% for most formulations. The SYP was treated with KATHON 930 in polyvinylpyridine. At levels of 0.1 kg of biocide/m3 of wood less than 5% of the SYP mass was lost after 50 days of exposure to Gloeophyllum trabeum. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 608–614, 2002
Diffusion behavior of hexane in diamine chain‐extended hydroxyterminated polybutadiene based polyurethanes
Authors: Gupta Tarakranjan , Adhikari Basudam
Published: October 2002

A new method of edge correction has been formulated to calculate the near true diffusion coefficient of hexane in thin polyurethane and polyurethaneurea sheets. The method involves the calculation of time‐average thickness during the diffusion of hexane in hydroxyterminated polybutadiene‐based polyurethane and polyurethaneurea sheets. The precision of the method has been tested by the iteration of data. The diffusion coefficient increases with the increase of diamine chain extender in polyurethaneureas. The variation of activation parameters and enthalpy of diffusion of hexane with diamine chain extender in polyurethaneurea also have been studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 90–97, 2002
Characterization and properties of sPS/PET/SsPS‐K engineering plastic alloys
Authors: Wang Jin , Zhu Fangming , Li Huaming , Lin Shang'an
Published: October 2002

The compatibility, crystallization behavior, and mechanical properties of syndiotactic polystyrene (sPS)/polyester (PET)/potassium salt of sulfonated syndiotactic polystyrene (SsPS‐K) were investigated. DMA results showed that all the alloys showed one Tg and the half‐peak width of the sPS/PET/SsPS‐K alloys became narrower compared with that of sPS/PET alloys, which decreased with an increasing content of the SsPS‐K ionomer. The results of DSC showed that the Tm of sPS and PET of the alloys was similar to those of the pure materials and did not change with the content of the SsPS‐K ionomer, while the initial crystallization temperature (T0) and crystallization temperature at peak (Tp) increased. The crystallization velocity of PET increased with an increasing content of SsPS‐K. The TMA results showed that the alloys could retain the perfect heat proof property of sPS. SEM micrographs showed that the addition of SsPS‐K could reduce the PET domain dimension and enhance the adhesion between the PET domains and the matrix. With an increasing content of SsPS‐K, the PET domain dimension was reduced continuously and dispersed more evenly. The ternary alloys had better mechanical properties and significantly higher unnotched Izod impact strength than those of the alloys without SsPS‐K. When the weight ratio of sPS/PET/SsPS‐K was 85/15/4, the impact strength reached a maximum of 11.5 kJ/m2, which was about three times that of pure sPS, and still had a higher tensile strength, flexural strength, and storage modulus, which were 38.8, 54.2, and 1.55 × 104 MPa, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 656–661, 2002
Development of a poly(N‐vinyl‐2‐pyrrolidone)/poly (ethylene glycol) hydrogel membrane reinforced with methyl methacrylate‐grafted polypropylene fibers for possible use as wound dressing
Authors: Lopérgolo L. C. , Lugão A. B. , Catalaini L. H.
Published: October 2002

A hydrogel is a polymeric material that exhibits the ability to swell in water and retains a significant fraction of water within its structure, but does not dissolve in water. One of the major problems in the application of these materials is their relatively poor mechanical strength, attributed to the high degree of hydration of the gel. This work was directed to the study of the interactions between hydrophobic and hydrophilized fibers, with the objective of optimization of the mechanical properties of poly(N‐vinyl‐2‐pyrrolidone) membranes. The membranes were prepared by electron‐beam irradiation of an aqueous polymer solution. A nonwoven cloth made of polypropylene matted fiber, grafted with methyl methacrylate, was employed as a reinforcement. The changes in the main properties of the membranes, such as the gel content, swelling characteristics, cytotoxicity, and mechanical behavior, were investigated. The results showed an increase of 800% in tensile strength, without changes in the swelling and cytotoxicity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 662–666, 2002
Synthesis and characterization of polyacrylamide‐grafted sodium alginate copolymeric membranes and their use in pervaporation separation of water and tetrahydrofuran mixtures
Authors: Kurkuri Mahaveer D. , Kumbar Sangamesh G. , Aminabhavi Tejraj M.
Published: October 2002

Polyacrylamide‐grafted sodium alginate (PAAm‐g‐Na‐Alg) copolymeric membranes have been prepared, characterized, and used in the pervaporation separation of 10–80 mass % water‐containing tetrahydrofuran mixtures. Totally three membranes were prepared: (1) neat Na‐Alg with 10 mass % of polyethylene glycol (PEG) and 5 mass % of polyvinyl alcohol (PVA), (2) 46 % grafted PAAm‐g‐Na‐Alg membrane containing 10 mass % of PEG and 5 mass % of PVA, and (3) 93 % grafted PAAm‐g‐Na‐Alg membrane containing 10 mass % of PEG and 5 mass % of PVA. Using the transport data, important parameters like permeation flux, selectivity, pervaporation separation index, swelling index, and diffusion coefficient have been calculated at 30°C. Diffusion coefficients were also calculated from sorption gravimetric data of water–tetrahydrofuran mixtures using Fick's equation. Arrhenius activation parameters for the transport processes were calculated for 10 mass % of water in the feed mixture using flux and diffusion data obtained at 30, 35, and 40°C. The separation selectivity of the membranes ranged between 216 and 591. The highest permeation flux of 0.677 kg/m2 h was observed for 93% grafted membrane at 80 mass % of water in the feed mixture. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 272–281, 2002
Water/ethanol pervaporation performance of asymmetric polyelectrolyte complex membrane constructed by the diffusion of poly(acrylic acid) in chitosan membrane
Authors: Iwatsubo Takashi , Kusumocahyo Samuel P. , Shinbo Toshio
Published: October 2002

Asymmetric polyelectrolyte complex (PEC) membranes composed of chitosan membrane and absorbed poly(acrylic acid) (PAA) were constructed. Absorption and therefore PEC formation were performed by bringing a chitosan membrane into contact with a PAA aqueous solution. The mean molecular weight (MW) of PAA employed was 5,000, 25,000 or 250,000. Absorption of PAA and asymmetry of PEC membranes were confirmed and evaluated by Fourier transform infrared (FTIR) spectra and electron spectroscopy for chemical analysis (ESCA). The absorption quantity of PAA decreased while the water selectivity of the PEC membrane increased with an increase in the MW of constituent PAA. In a pervaporation experiment, the water selectivity of the membrane was so high that no ethanol was detected by gas chromatography (GC). Such selectivity was attained by just a small quantity of PEC formation at the surface of the chitosan membrane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 265–271, 2002
Structure development during dry–jet–wet spinning of acrylonitrile/vinyl acids and acrylonitrile/methyl acrylate copolymers
Authors: Bajaj P. , Sreekumar T. V. , Sen K.
Published: October 2002

Dry–jet–wet spinning of three copolymers, poly(acrylonitrile/methyl acrylate), poly(acrylonitrile/methacrylic acid), and poly(acrylonitrile/itaconic acid), was performed with a dimethylformamide/water (60:40 v/v) coagulation bath at different temperatures (10–40°C). The fibers were stretched to different levels (1.1–6×) in boiling water, collapsed, and annealed over a heater plate at 130°C. The effects of the polymer composition, coagulation bath temperature, and draw ratio on the cross‐sectional morphology, structure, and tensile properties are reported. The cross‐sectional shape of the gel fibers underwent a transition from a kidney shape to an oval shape, and macrovoids began to appear at higher temperatures. However, F(AN/IA) gel fibers changed from a kidney shape to an irregular shoe type with a gel network of interconnected polymer fibrils. For F(AN/MAA) gel fibers, the diameter increased from 45 to 67 μm when the coagulation bath temperature was increased from 10 to 40°C, and the denier value decreased from 17.5 to 14.3 den/filament. The strength, modulus, and elongation at break decreased with an increase in the coagulation bath temperature. For F(AN/MAA) fibers coagulated at 10°C in a spin bath, the strength increased from 0.43 to 2.213 g/den, the modulus increased from 27 to 76 g/den, and the density increased from 1.177 to 1.196 g cm−3 when the gel fibers were drawn to 6×. However, 6× drawn F(AN/MA) fibers had a higher strength (3.1 g/den) and elongation (14.6%) in a 40°C coagulation bath. F(AN/IA) fibers could be drawn only to a draw ratio of 4× instead of the 6× draw ratio for F(AN/MAA) and F(AN/MA) fibers. Therefore, the final F(AN/IA) fibers exhibited poor mechanical properties (tenacity = 0.81 g/den, modulus = 22 g/den, and elongation at break = 8%). The crystallinity did not change significantly (χc = 61–63%) with the draw ratio, but the crystal size increased from 22.9 to 43.4 Å and orientation factor from 0.41 to 0.78. The dichroic ratio, measured with Fourier transform infrared, decreased with an increase in the draw ratio, but the sonic modulus and crystalline orientation values increased with an increase in the draw ratio. Thermomechanical data show a maximum physical shrinkage of 51.7% for 6× drawn F(AN/MA) and a minimum physical shrinkage of 30.5% for 4× drawn F(AN/IA) fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 773–787, 2002
Starch derivatives of a high degree of functionalization. VI. Multistep carboxymethylation
Authors: Lazik W. , Heinze Th. , Pfeiffer K. , Albrecht G. , Mischnick P.
Published: October 2002

For the first time, carboxymethyl starch (CMS) samples with a very high degree of substitution (DSCM = 2.1) were synthesized by multistep carboxymethylation under heterogeneous reaction conditions in methanol/water with sodium hydroxide and monochloroacetic acid as an etherifying agent. The stepwise increase in the total DSCM value gradually decreased with an increasing DSCM value of the starting polymer. The determination of the functionalization pattern of CMS by 1H‐NMR spectroscopy after chain degradation indicated a high preference for 2‐O‐substitution. The distribution of the carboxymethyl functions was in the order O‐2 ≫ O‐6 > O‐3. A detailed analysis of the depolymerized sample by means of high‐performance liquid chromatography and capillary electrophoresis revealed a monomer composition that was in very good agreement with the statistical model of Spurlin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 743–752, 2002
Degradation studies of LDPE–Mater‐Bi blends annealed and aged in soil
Authors: Vallés‐Lluch A. , Contat‐Rodrigo L. , Ribes‐Greus A.
Published: October 2002

Blends of low‐density polyethylene (LDPE) and a commercial biodegradable material commonly used as an additive, Mater‐Bi AF05H, were subjected to thermal treatment followed by an accelerated soil burial test in a culture oven. The effect of the degradation process on the structural and morphological properties of the samples was studied by differential scanning calorimetry and dynamic mechanical thermal analysis. The morphological properties studied in this work 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 and the αII and β relaxations were characterized in terms of E″ according to the Fuoss–Kirkwood equation and using a deconvolution method. It was found that the thermal treatment rearranges the crystallites in the crystalline phase and promotes a segregation of the crystallite sizes. However, the annealing seems rather to hinder than to improve the degradation of the samples. Moreover, the degradation process in the blends apparently starts in the Mater‐Bi. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 405–413, 2002
Effect of PMR‐POI on the melt behavior and isothermal crystallization of poly(phenylene sulfide)
Authors: Lai Mingfang , Yang Huili , Luan Yucheng , Yang Yuming , Liu Jingjiang
Published: October 2002

The crystallization behavior of neat PPS and PPS in blends with PMR‐POI prepared by melt mixing were investigated by differential scanning calorimetry (DSC). It was found that POI was an effective nucleation agent of the crystallization for PPS. The enthalpy of crystallization of PPS in the blends increased compared with that of neat PPS. During isothermal crystallization from melt, the dependence of relative degree of crystallinity on time was described by the Avrami equation. It has been shown that the addition of POI causes an increase in the overall crystallization rate of PPS; it also changed the mechanism of nucleation of the PHB crystals from homogeneous nucleation to heterogeneous nucleation. The equilibrium melting temperature of PPS and PPS/POI blends were determined. The analysis of kinetic data according to nucleation theories shows that the increase in crystallization rate of PPS in the composite is due to the decrease in surface energy of the extremity surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 436–442, 2002
Claudin localization in cilia of the retinal pigment epithelium
Authors: Nishiyama Kazutoshi , Sakaguchi Hirokazu , Hu Jane G. , Bok Dean , Hollyfield Joe G.
Published: October 2002

Using immunocytochemistry and confocal microscopy we demonstrate that claudin‐immunoreactivity is a novel marker for retinal pigment epithelial cilia. Claudin‐immunoreactivity obtained by polyclonal anti‐claudin 1 antibody, which could crossreact with claudin 3, was colocalized with acetylated tubulin‐immunoreactivity in cultured human retinal pigment epithelial cells. Claudin‐immunoreactivity associated with the retinal pigment epithelium (RPE) cilia was more intense than was claudin‐immunoreactivity in the junctional complex. Approximately two‐thirds of the RPE cells in the rat contain cilia that are immunoreactive with acetylated tubulin on postnatal day 1, and a significant portion of these cilia label with the anti‐claudin 1 antibody. Cilia decrease in frequency over subsequent postnatal days, and are absent by postnatal day 30. As RPE cilia decrease in number during postnatal rat development, claudin‐immunoreactivity is lost earlier than acetylated tubulin, suggesting that the loss of claudin may initiate RPE cilium degeneration. Claudin‐immunoreactivity was not evident in cilia of photoreceptor cells, epithelia of nasal mucosa, small intestine, or colon, suggesting that claudin may be a unique molecule in RPE cilia. These data suggest that cilia of the RPE, unlike cilia on other cell types, contain claudin, and that this molecule may play an important and specific role in the function and/or maintenance of RPE cilia. Anat Rec 267:196–203, 2002. © 2002 Wiley‐Liss, Inc.
Morphological characteristics of the vomeronasal organ of the newborn Asian elephant (Elephas maximus)
Authors: Johnson Edward W. , Rasmussen Lel
Published: October 2002

The 6‐week‐old Asian elephant (Elephas maximus) has a well‐documented precocious flehmen response to pheromones, suggesting that the pheromone‐detecting vomeronasal organ (VNO) is functional very early in the life of this species. To further document this, the VNOs of two newborn elephants were examined in situ and analyzed by light microscopy (LM) to ascertain their structural maturity at birth. A tubular, cartilage‐encased VNO was located along the anterior base of each side of the nasal septum. Its rostral end was connected to a duct to the roof of the mouth; the caudal end was attached to a well‐defined vomeronasal nerve projecting toward the brain. LM revealed distinctive differences in the mucosae bordering the horseshoe‐shaped lumen: a concave, sensory mucosa, and a convex, nonsensory mucosa. Small groups of receptor neurons were observed among ciliated columnar cells in the sensory epithelium. Numerous unmyelinated nerve bundles and blood vessels filled the underlying lamina propria (LP) and a small section of the vomeronasal nerve was conspicuous at one edge. The nonsensory mucosa manifested a thinner epithelium that principally consisted of ciliated columnar cells, some of which showed a granular cytoplasm, and a conspicuous row of basal cells. The LP was replete with acinar glands and ducts that opened into the lumen. This study shows that the VNO of the newborn elephant has reached an advanced stage of structural maturity, closely resembling that of the adult. Its composition supports the view that flehmen at 6 weeks delivers pheromones to a functional VNO. Anat Rec 267:252–259, 2002. © 2002 Wiley‐Liss, Inc.
Material properties of the inner and outer cortical tables of the human parietal bone
Authors: Peterson Jill , Dechow Paul C.
Published: October 2002

Even though the cranial vault functions as protection for the brain and as a support structure for facial and masticatory functions, little is known about its mechanical properties or their variations. The cranial vault bone is interesting because of its maintenance in spite of low functional strains, and because calvarial bone cells are often used in cell culture studies. We measured thickness, density, and ash weight, and ultrasonically determined elastic properties throughout the cortices of 10 human parietal bones. The results are unique for studies of the cranial vault because: 1) measurements focused specifically on the cortical components, 2) the orientations of the axes of maximum stiffness were determined before measurement of elastic properties, and 3) two related measurements (bone density and percent ash weight) were compared. Results showed that the periosteal cortical plate (outer table) and the endosteal cortical plate (inner table) had significant differences in material properties. The outer table was on average thicker, denser, and stiffer than the inner table, which had a higher ash weight percentage. Within each table there were significant differences in thicknesses, ash weight percentages, and E2/E3 anisotropies among sites. Few sites on either table had significant orientations of the axes of maximum stiffness. Despite this apparent randomness in orientation, almost all sites exhibited anisotropies equivalent to other parts of the skeleton. Anat Rec 268:7–15, 2002. © 2002 Wiley‐Liss, Inc.
Analysis of involvement of the 3′‐untranslated regions in regulating mRNA stability for vitellogenin, cyanoprotein α, and cyanoprotein β from the bean bug, Riptortus clavatus
Authors: Wojtasek Hubert , Miura Ken , Shinoda Tetsuro , Chinzei Yasuo
Published: October 2002

The degradation of the 3′‐untranslated regions (UTRs) of vitellogenin, cyanoprotein α, and cyanoprotein β from the bean bug, Riptortus clavatus, was analyzed in vitro. The degradation pattern was similar for all three RNAs, with a high degradation rate in non‐diapausing adult insects and no degradation in the fifth instar nymphs and in diapausing adults, and was not correlated with the expression levels of these three proteins. Proteins binding to the 3′‐UTRs were detected in polysomal and cytosolic extracts. These factors, however, were present in all developmental stages. The abundance of the polysomal factor showed little variation, but the cytosolic factor was enriched in adult insects. Cross‐competition experiments demonstrated that the same factors bound to all three RNAs with similar affinity. The pattern of degradation, presence of the binding factors in all stages, and their inability to distinguish between the target sequences indicate that the 3′‐UTRs do not participate in controlling the expression of these three proteins. Arch. Insect Biochem. Physiol. 51:27–36, 2002. © 2002 Wiley‐Liss, Inc.