bluuebunny/crossref_metadata_2025 huggingface dataset:
Human T‐lymphotropic virus type II and neurological disease
Authors: Araujo Abelardo , Hall William W.
Published: June 2004

Human T‐lymphotropic virus type I (HTLV‐I) and type II (HTLV‐II) are closely related retroviruses with similar biological properties and common modes of transmission. HTLV‐I infection is endemic in well‐defined geographic regions, and it is estimated that some 20 million individuals are infected worldwide. Although most infected individuals are asymptomatic carriers, some 2 to 5% will develop a chronic encephalomyelopathy, HTLV‐I–associated myelopathy/tropical spastic paraparesis (HAM/TSP). In contrast with HTLV‐I, the role of HTLV‐II in the development of neurological disorders is much less clear. HTLV‐II is endemic in many native Amerindian groups and epidemic in injecting drug users (IDUs) worldwide. To evaluate the role of HTLV‐II in neurological disease, we have critically reviewed all reported cases of HTLV‐II–associated disorders. This has confirmed that although rare infection is associated with a disorder clinically similar or identical to HAM/TSP. However, most reports that have attributed infection to a range of other neurological disorders are difficult to evaluate in that in many cases either the association appears to be fortuitous or the presentations were confounded by a background of concomitant human immunodeficiency virus–1 infection and/or active IDU. In view of the many HTLV‐II–infected individuals in urban areas of North America and Europe, neurologists should be aware of the potential clinical consequences of this infection.
Prevention of neuropathology in the mouse model of hurler syndrome
Authors: Desmaris Nathalie , Verot Lucie , Puech Jean Philippe , Caillaud Catherine , Vanier Marie Thérèse , Heard Jean Michel
Published: June 2004

A defect of the lysosomal enzyme α‐L‐iduronidase (IDUA) interrupts heparan and dermatan sulfate degradation and causes neuropathology in children with severe forms of mucopolysaccharidosis type I (MPSI, Hurler syndrome). Enzyme substitution therapy is beneficial but ineffective on the central nervous system. We could deliver the missing enzyme to virtually the entire brain of MPSI mice through a single injection of gene transfer vectors derived from adenoassociated virus serotype 2 (AAV2) or 5 (AAV5) coding for human IDUA. This result was reproducibly achieved with both vector types in 46 mice and persisted for at least 26 weeks. Success was more frequent, enzyme activity was higher, and corrected areas were broader with AAV5 than with AAV2 vectors. Treatment presumably reversed and certainly prevented the accumulation of GM2 and GM3 gangliosides, which presumably participates to neuropathology. Lysosomal distension, which already was present at the time of treatment, had disappeared from both brain hemispheres and was minimal in the cerebellum in mice analyzed 26 weeks after injection. This study shows that pathology associated with MPSI can be prevented in the entire mouse brain by a single AAV vector injection, providing a preliminary evaluation of the feasibility of gene therapy to stop neuropathology in Hurler syndrome. Ann Neurol 2004;56:68–76
Long‐term effect of motor cortical repetitive transcranial magnetic stimulation induces
Authors: Hayashi Takuya , Ohnishi Takashi , Okabe Shingo , Teramoto Noboru , Nonaka Yukio , Watabe Hiroshi , Imabayashi Etsuko , Ohta Yoichiro , Jino Hiroshi , Ejima Norimasa , Sawada Tohru , Iida Hidehiro , Matsuda Hiroshi , Ugawa Yoshikazu
Published: June 2004

Repetitive transcranial magnetic stimulation (rTMS) recently has been assessed as a noninvasive treatment modality for movement and psychiatric disorders, whereas the mechanism underlying the therapeutic effects is not fully understood. Studies in rodents showed lasting functional changes in some selected regions, such as limbic‐associated structures, but unfocused brain stimulation did not clarify the regional effects. To address the topographical and temporal profiles of the effects on glucose metabolism in primate brain, we performed rTMS and repeated 18F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) before, during, and up to 16 days after rTMS in anesthetized cynomologous monkeys. We delivered a total of 2,000 pulses of 5Hz‐rTMS over the right precentral gyrus using a small‐sized eight‐figured coil that induced a localized electrical field. Voxel‐based analysis in a standard space of the macaque brain showed statistically robust changes in FDG uptake: a decrease in the motor/premotor cortices and an increase in the limbic‐associated areas involving the anterior/posterior cingulate, and orbitofrontal cortices. Interestingly, these uptake changes continued for at least 8 days and the magnitude of the lasting effects in the limbic‐related areas was negatively correlated across subjects with those in the motor/premotor cortices. The results demonstrate that motor rTMS has a long‐term lasting effect on motor‐related regions and distant limbic‐related areas via functional connections.
Is benign rolandic epilepsy genetically determined?
Authors: Vadlamudi Lata , Harvey A. Simon , Connellan Mary M. , Milne Roger L. , Hopper John L. , Scheffer Ingrid E. , Berkovic Samuel F.
Published: June 2004

Benign rolandic epilepsy (BRE) is considered to be a genetically determined idiopathic partial epilepsy. We studied twins with BRE and compared the concordance with a twin sample of idiopathic generalized epilepsy (IGE). All eight BRE pairs (six monozygous [MZ], two dizygous [DZ]) were discordant. MZ pairwise concordance was 0 (95% confidence interval [CI], 0–0.4) for BRE compared with 0.7 (95% CI, 0.5–0.9) for 26 IGE MZ pairs. Our data suggest that conventional genetic influences in BRE are considerably less than for IGE, and other mechanisms need to be explored. Ann Neurol 2004;56:129–132
Heterogeneity of nemaline myopathy cases with skeletal muscle α‐actin gene mutations
Authors: Agrawal Pankaj B. , Strickland Corinne D. , Midgett Charles , Morales Ana , Newburger Daniel E. , Poulos Melisa A. , Tomczak Kinga K. , Ryan Monique M. , Iannaccone Susan T. , Crawford Tom O. , Laing Nigel G. , Beggs Alan H.
Published: June 2004

Nemaline myopathy (NM) is the most common of several congenital myopathies that present with skeletal muscle weakness and hypotonia. It is clinically heterogeneous and the diagnosis is confirmed by identification of nemaline bodies in affected muscles. The skeletal muscle α‐actin gene (ACTA1) is one of five genes for thin filament proteins identified so far as responsible for different forms of NM. We have screened the ACTA1 gene in a cohort of 109 unrelated patients with NM. Here, we describe clinical and pathological features associated with 29 ACTA1 mutations found in 38 individuals from 28 families. Although ACTA1 mutations cause a remarkably heterogeneous range of phenotypes, they were preferentially associated with severe clinical presentations (p < 0.0001). Most pathogenic ACTA1 mutations were missense changes with two instances of single base pair deletions. Most patients with ACTA1 mutations had no prior family history of neuromuscular disease (24/28). One severe case, caused by compound heterozygous recessive ACTA1 mutations, demonstrated increased α‐cardiac actin expression, suggesting that cardiac actin might partially compensate for ACTA1 abnormalities in the fetal/neonatal period. This cohort also includes the first instance of an ACTA1 mutation manifesting with adult‐onset disease and two pedigrees exhibiting potential incomplete penetrance. Overall, ACTA1 mutations are a common cause of NM, accounting for more than half of severe cases and 26% of all NM cases in this series. Ann Neurol 2004;56:86–96
Persistent NKH with transient or absent symptoms and a homozygous GLDC mutation
Authors: Korman Stanley H. , Boneh Avihu , Ichinohe Akiko , Kojima Kanako , Sato Kenichi , Ergaz Zivanit , Gomori John M. , Gutman Alisa , Kure Shigeo
Published: June 2004

Three of four nonketotic hyperglycinemia patients homozygous for a novel GLDC mutation (A802V) were treated by assisted respiration and/or sodium benzoate with or without ketamine and had transient neonatal or absent symptoms and normal developmental outcome, despite persisting biochemical evidence of nonketotic hyperglycinemia. This exceptional outcome may be related to the high residual activity of the mutant protein (32% of wild type) and therapeutic intervention during a critical period of heightened brain exposure and sensitivity to glycine. Ann Neurol 2004;56:139–143
MR molecular imaging of early endothelial activation in focal ischemia
Authors: Barber Philip A. , Foniok Tadeusz , Kirk David , Buchan Alastair M. , Laurent Sophie , Boutry Sébastien , Muller Robert N. , Hoyte Lisa , Tomanek Boguslaw , Tuor Ursula I.
Published: June 2004

Focal ischemia followed by reperfusion initiates a harmful P‐ and E‐selectin–mediated recruitment of leukocytes in brain microvasculature. In this study, we tested whether a novel magnetic resonance (MR) contrast agent (Gd‐DTPA‐sLex A), which is designed to bind to activated endothelium could be detected by MR imaging (MRI) in a focal stroke mouse model. MRIs (9.4T) of the brain were acquired 24 hours after transient middle cerebral artery occlusion. T1 maps were acquired repeatedly before and up to 1.5 hours after the intravenous injection of either Gd‐DTPA or Gd‐DTPA‐sLex A. Analysis of images included a pixel‐by‐pixel subtraction of T1 maps from the precontrast T1 maps and quantification of T1 within the ischemic area. After injection of Gd‐DTPA‐sLex A, T1 decreased compared with precontrast levels, and an interhemispheric difference between the pre–post contrast T1 developed within the stroke lesion at a mean time of 52 minutes after injection (p < 0.05). Animals injected with Gd‐DTPA did not exhibit changes in T1 signal intensity between regions of the ipsilateral and contralateral hemispheres, indicating that the reductions in T1 observed with Gd‐DTPA‐sLex A were unrelated to blood–brain barrier breakdown. Fluorescent‐labeled sLex A administered intravenously was observed to bind to the endothelium of injured but not control brain. The study suggests that the contrast agent Gd‐DTPA‐sLex A can be used to visualize early endothelial activation after transient focal ischemia in vivo with MRI. Ann Neurol 2004;56:116–120
High‐frequency oscillations recorded in human medial temporal lobe during sleep
Authors: Staba Richard J. , Wilson Charles L. , Bragin Anatol , Jhung Donald , Fried Itzhak , Engel Jerome
Published: June 2004

The presence of fast ripple oscillations (FRs, 200–500Hz) has been confirmed in rodent epilepsy models but has not been observed in nonepileptic rodents, suggesting that FRs are associated with epileptogenesis. Although studies in human epileptic patients have reported that both FRs and ripples (80–200Hz) chiefly occur during non–rapid eye movement sleep (NREM), and that ripple oscillations in human hippocampus resemble those found in nonprimate slow wave sleep, quantitative studies of these oscillations previously have not been conducted during polysomnographically defined sleep and waking states. Spontaneous FRs and ripples were detected using automated computer techniques in patients with medial temporal lobe epilepsy during sleep and waking, and results showed that the incidence of ripples, which are thought to represent normal activity in animal and human hippocampus, was similar between epileptogenic and nonepileptogenic temporal lobe, whereas rates of FR occurrence were significantly associated with epileptogenic areas. The generation of both FRs and ripples showed the highest rates of occurrence during NREM sleep. During REM sleep, ripple rates were lowest, whereas FR rates remained elevated and were equivalent to rates observed during waking. The predominance of FRs within the epileptogenic zone not only during NREM sleep, but also during epileptiform‐suppressing desynchronized episodes of waking and REM sleep supports the view that FRs are the product of pathological neuronal hypersynchronization associated with seizure‐generating areas. Ann Neurol 2004;56:108–115
Cover Picture: Angew. Chem. Int. Ed. 1/2003
Authors: Lin Hong , Danishefsky Samuel J.
Published: June 2004

The Art of Synthesis and the beauty of Nature lure so many chemists into total synthesis. The cover picture shows yellow jasmine in full bloom, from which the poisonous alkaloid gelsemine was isolated. The formula of gelsemine and important intermediates from six total syntheses are overlaid on the photograph. From these syntheses, we can learn which strategies represent the fastest and/or most efficient routes to the target. More about this fascinating compound and organic synthesis at its best can be found in the Review by S. J. Danishefsky and H. Lin on pg. 36 ff.
Hadamard Transform Time‐of‐Flight Mass Spectrometry: More Signal, More of the Time
Authors: Zare Richard N. , Fernández Facundo M. , Kimmel Joel R.
Published: June 2004

Hadamard transform time‐of‐flight mass spectrometry (HT‐TOF MS) is a type of mass analysis that was developed to couple continuous ion sources to the inherently pulsed nature of time‐of‐flight measurements. Unlike conventional TOF MS, the Hadamard transform method offers a duty cycle of 50 %, with the possibility of extending it to 100 %. Because it is a multiplexing technique, the attainable signal‐to‐noise ratio (SNR) is also significantly higher than that of conventional TOF MS. This review covers the basic principles behind HT‐TOF MS. We illustrate, through examples, the source of the high‐duty cycle and the increase in SNR. These features translate to a mass spectral storage rate that is the fastest among similar instruments, which enables its use as a detector for high‐speed separations.
Gelsemine: A Thought‐Provoking Target for Total Synthesis
Authors: Lin Hong , Danishefsky Samuel J.
Published: June 2004

Gelsemine and 21‐oxogelsemine have been synthesized through several routes. This Review focuses on the comparison of the different strategies to assemble the bicyclo[3.2.1]octane core, to introduce the bridgehead quaternary C20 to form the pyrrolidine moiety, to construct the oxindole residue, and to close the tetrahydropyran ring en route to gelsemine.
Polymerization conversion and structure of magnesium methacrylate in ethylene–vinyl acetate rubber vulcanizates
Authors: Du Aihua , Peng Zonglin , Zhang Yong , Zhang Yinxi
Published: June 2004

Ethylene–vinyl acetate rubber (EVM) filled with magnesium methacrylate (MDMA) was cured with dicumyl peroxide (DCP). The experimental results showed that the mechanical properties of MDMA/EVM vulcanizates were superior to those of high‐abrasion furnace carbon black/EVM vulcanizates. The tensile strength of the MDMA/EVM vulcanizate could reach 22.5 MPa and the tear strength was 83.5 kN/m, whereas its elongation at break remained over 300%, even when the MDMA content was 50 phr. FTIR analysis confirmed that polymerization of MDMA occurred under the initiation of DCP, and the polymerization conversion of MDMA decreased with the increase of MDMA content. When the MDMA content increased from 10 to 50 phr, the conversion of MDMA in EVM decreased from 68 to 20%. SEM and TEM observations indicated that 20 μm particles of MDMA powder changed into about 20 nm particles during the curing process, and the finer particles dispersed evenly in the EVM vulcanizates. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2379–2384, 2004
The effect of paraffin on fiber dispersion and mechanical properties of polyolefin–sawdust composites
Authors: Viksne Armanda , Rence Ligita , Kalnins Martins , Bledzki Andzej K.
Published: June 2004

This article reports on the influence of the paraffin (PAR) on the wood fiber (WF) dispersion in different polyethylene (low‐density polyethylene, high‐density polyethylene, recycled polyethylene) matrices, as well as on the melt flow behavior and mechanical properties of WF‐reinforced polyethylene (PE) composites. In the presence of paraffin, the composites showed improved tensile and flexural strength and modulus, but lower impact strength and elongation at break. The extent of improvement in mechanical properties depends on paraffin content and type of polyethylene; the most effective paraffin was in LDPE‐based composites. Paraffin‐treated WF showed lower moisture absorption ability in comparison with unmodified wood fiber. The phase segregation process was investigated for PE/PAR blends by DSC method. It was shown that an increase of paraffin concentration in the PE/PAR blend leads to a decrease of PE melting temperature and an increase of paraffin melting temperature; it indicates a net exchange of material from paraffin towards polyethylene. However, generally both components of PE/PAR blends remain immiscible. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2385–2393, 2004
Natural rubber composites reinforced with sisal/oil palm hybrid fibers: Tensile and cure characteristics
Authors: Jacob Maya , Thomas Sabu , Varughese K. T.
Published: June 2004

Natural rubber was reinforced with untreated sisal and oil palm fibers chopped to different fiber lengths. The influence of fiber length on the mechanical properties of the hybrid composites was determined. Increasing the fiber length resulted in a decrease in the properties. The effects of concentration on the rubber composites reinforced with sisal/oil palm hybrid fibers were studied. Increasing the concentration of fibers resulted in a reduction in the tensile strength properties and tear strength but an increase in the modulus of the composites. Fiber breakage analysis was evaluated. The vulcanization parameters, processability characteristics, and stress–strain properties of these composites were analyzed. The extent of fiber alignment and the strength of the fiber–rubber interface adhesion were analyzed from the anisotropic swelling measurements. Scanning electron microscopy studies were performed to analyze the fiber/matrix interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2305–2312, 2004
Properties of water‐blown rigid polyurethane foams with reactivity of raw materials
Authors: Seo W. J. , Park J. H. , Sung Y. T. , Hwang D. H. , Kim W. N. , Lee H. S.
Published: June 2004

Rigid polyurethane foams (PUFs) were prepared from polymeric 4,4‐diphenylmethane diisocyanate (PMDI; having functionality of 2.9), polyether polyols, silicone surfactant, amine catalysts, and distilled water. The effects of reactivity on the properties such as density, compressive and flexural strength, and glass‐transition temperature (Tg) of the PUF samples were studied. The kinetic rate of forming the PUF samples was increased with the catalyst and water content. With increasing OH value and functionality of the polyols, the density and compressive strength of the PUF samples also increased. For the PUF samples synthesized with polyols having high functionality (>5), the flexural strength of the PUF samples decreased with the functionality of the polyols. With increasing OH value and functionality of the polyols, the Tg of the PUF increased because of an increase in the degree of crosslinking of the PUF samples. The Tg value and compressive strength of the PUF samples were observed to increase with the NCO index. From this result, it was suggested that the increase in the Tg value and compressive strength of the PUF samples may be attributable to the additional crosslinks that arose from allophonate and biuret formation by the supplementary reactions of excess PMDI. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2334–2342, 2004
Kinetics of a thermooxidative degradation of polyethylene: Fractal analysis
Authors: Kozlov G. V. , Shustov G. B. , Zaikov G. E.
Published: June 2004

It is shown that kinetics of polyethylene thermooxidative degradation is influenced by both spatial and temporary (energetic) disorder of structure. Thus, the theorem of subordination is carried out (i.e., the multiplicative behavior of exponents describing these kinds of disorder is observed). As heat aging is usually carried out at rather high temperatures, this circumstance leads in an increase of contribution of temporary (energetic) disorder. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2348–2351, 2004
A scaling analysis of a friction processes of polyarylate
Authors: Kozlov G. V. , Burya A. I. , Zaikov G. E.
Published: June 2004

The obtained data infer the applicability and usefulness of the scaling approach and fractal analysis for the description of friction and wearing processes of polymers. The scaling nature of the relationships used for the description of the above‐mentioned processes is confirmed. Shown within the framework of the fractal analysis is the interdependence between the structure of polymer and parameters involved in these relationships, which were considered previously as empirical. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2352–2355, 2004
Ultrasonically irradiated emulsion copolymerization of styrene and surfmer
Authors: Zhang Jingzhi , Cao Ya
Published: June 2004

The nonionic surfmer AREO7 was first used in the ultrasonically irradiated emulsion polymerization of styrene. The added AREO7 could improve the emulsion solid content. Through FTIR, GC‐MS, and DSC studies, it was found that the polymer produced was the copolymer of styrene and AREO7. The copolymer latics polymerized in proper conditions displayed nanoparticles. When AREO7 concentration increased, there were more nanostructured copolymer gels, in which AREO7 molecules form an amphiphilic network, whereas polystyrene was located in hydrophobic droplet. The latics had a structured morphology that the AREO7 units were mainly on the surface of particles. The glass transition temperature (Tg) of copolymers decreased with the increase of AREO7 composition in copolymers. Freeze–thaw test showed that the freeze–thaw stability of the copolymer emulsion was improved greatly because of the increasing composition of AREO7 in copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2356–2362, 2004
Morphologies and mechanical properties of polylactide blends with medium chain length poly(3‐hydroxyalkanoate) and chemically modified poly(3‐hydroxyalkanoate)
Authors: Takagi Yasuo , Yasuda Ryou , Yamaoka Michimasa , Yamane Tsuneo
Published: June 2004

Blends of bacterial poly(3‐hydoroxyalkanoate) (PHA) with a medium‐length side chain and polylactide (PLA), and blends of the chemically modified PHA (ePHA) with PLA, were prepared. The morphologies, some physical properties, and thermal behavior of the blends based on PLA were investigated by electron microscopies, testing machines, and a differential scanning calorimeter, respectively. A blend of uncrystallized rubbery second components, PHA and ePHA, produced an increase in the impact toughness of the PLA blends in contrast to a decrease in the tensile strength value. PHA, especially, with an inserted epoxy group side chain was more effective in improving the morphology and the physical properties than PHA. The ePHA particles existed in the PLA domain as a dispersed phase having a size of 0.1–1 μm. The results of the biodegradation test demonstrated that the PLA blends still maintained their biodegradability and were more accessible to hydrolysis and microbial attack, resulting in a greater weight loss than the pure PLA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2363–2369, 2004
Preparation of conductive polyaniline‐sulfonated EPDM ionomer composites from in situ emulsion polymerization and study of their properties
Authors: Xie Hong‐Quan , Pu Qing‐Lin , Xie Dong
Published: June 2004

The composites of polyaniline (PAn) and zinc sulfonated ethylene–propylene–diene rubber (EPDM) ionomer were made by polymerization of aniline in the presence of the ionomer by using a direct, one‐step in situ emulsion polymerization technique. The ionomers were prepared by sulfonation of EPDM rubber with acetyl sulfate in petroleum ether, followed by neutralization with zinc acetate solution. The ionomers with sulfonate contents of 10, 24, and 42 mmol SO3H/100 g were used for preparation of PAn/ionomer composites. The in situ polymerization of aniline was carried out in an emulsion comprising water and xylene containing the ionomer in the presence of dodecyl benzene sulfonic acid, acting as both a surfactant and a dopant for PAn. The composite was characterized by IR and WAXD. The composite obtained can be processed by melt method. The conductivity of the composite with lower sulfonate content was higher than that with higher sulfonate content. Conductivity of the composites exhibits a percolation threshold at about 13 wt % PAn. When the sulfonated content is 10 or 24 mmol SO3H/100 g and PAn content is 4–10 wt %, the composites behave as a thermoplastic elastomers with high ultimate elongation and low permanent set. The conductivity of the composite after secondary doping with m‐cresol is higher than the composite before secondary doping by about one order. Addition of zinc stearate as an ionic plasticizer lowers both the conductivity and the mechanical strength of the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2211–2217, 2004
Adhesive properties of epoxy resin modified by end‐functionalized liquid polybutadiene
Authors: Barcia Fabio L. , Soares Bluma G. , Sampaio Eduardo
Published: June 2004

Adhesive properties of epoxy resin networks modified with different functionalized liquid polybutadiene were evaluated by using aluminum adherent. The end‐functionalized polybutadiene rubbers were hydroxyl‐ (HTPB), carboxyl‐ (CTPB), and isocyanate‐terminated polybutadiene (NCOTPB). The adhesive properties depend upon the morphology and the degree of interaction between the rubber–epoxy system. The most effective adhesive for Al–Al joint in both butt and single‐lap shear testing was epoxy resin–NCOTPB system. This system presents stronger rubber–epoxy interactions and a higher degree of rubber particle dispersion with particle size diameter in the nanoscale range. These characteristics were not important for improving the toughness of the bulk network but are fundamental for the improvement of adhesive strength. The effect of the pretreatment of the aluminum surface on the roughness was also evaluated by using profilometry analysis. The type of failure was also investigated by analyzing the adhered surfaces after fracture by scanning electron microscopy and profilometry. A proportion of cohesion failure higher than 90% was observed in all systems. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2370–2378, 2004
Polymeric proton conducting systems based on commercial elastomers. II. Synthesis and microstructural characterization of films based on HSBR/EPDM/PP/PS/silica
Authors: Escribano P. G. , Nacher A. , Del Rio C. , González L. , Acosta J. L.
Published: June 2004

This article reports on the synthesis and structural characterization of films containing hydrogenated poly(butadiene‐styrene) block copolymer/ethylene‐propylene terpolymer/polypropylene, hydrogenated poly(butadiene‐styrene) block copolymer/ethylene‐propylene terpolymer/polystyrene, and hydrogenated poly(butadiene‐styrene block copolymer/ethylene‐propylene terpolymer/silica) crosslinked with peroxides and heterogeneously sulfonated. Sulfonation of the different polymeric systems gives rise to materials with high proton conductivity and great dimensional stability, suited for application in a variety of electronic devices. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2394–2402, 2004
Effect of the monomer ratio on the properties of poly(methyl methacrylate butyl acrylate) latex‐modified mortars
Authors: Pei Meishan , Wu Yue , Kim Wanki , Hyung Wongil , Soh Yangseob
Published: June 2004

This article deals with the effect of the monomer ratio on the typical properties of polymer‐modified mortars with poly(methyl methacrylate butyl acrylate) latices. Polymer‐modified mortars, with methyl methacrylate/butyl acrylate copolymer latices of various methyl methacrylate/butyl acrylate ratios, were prepared with different polymer/cement ratios and were tested for their workability, air content, compressive strength, flexural strength, and water absorption. On the basis of the test results, the effects of the monomer ratio and polymer/cement ratio on the typical properties were examined. The properties of the latex‐modified mortars were affected to a great extent by both the monomer ratio and polymer/cement ratio. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2403–2409, 2004
Improved mechanical properties of shape‐memory polyurethane block copolymers through the control of the soft‐segment arrangement
Authors: Cho Jae Whan , Jung Yong Chae , Chung Yong‐Chan , Chun Byoung Chul
Published: June 2004

High‐performance shape‐memory polyurethane block copolymers, prepared with two types of poly(tetramethylene glycol) (PTMG) used as soft segments, were investigated for their mechanical properties. Copolymers with a random or block soft‐segment arrangement had higher stresses at break and elongations at break than those with only one kind of PTMG. Random copolymers with fewer interchain interactions showed higher elongation than block copolymers. All the copolymers had shape‐recovery ratios higher than 80%. In dynamic mechanical testing, the glass‐transition behavior clearly depended on the soft‐segment arrangement: random copolymers had only one glass‐transition peak, whereas block copolymers showed two separate glass‐transition peaks. Overall, the control of the soft‐segment arrangement plays a vital role in the development of high‐performance shape‐memory polyurethane. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2410–2415, 2004
Synthesis of dextran dicarboxylic acid and investigation of its complexes with metal ions in aqueous solutions
Authors: Şenöz Hülya , Güner Alı , Tunoğlu Nazan
Published: June 2004

Dextran dicarboxylic acid was successfully synthesized by the direct oxidation of dextran with sodium chlorite and its characterization was realized by means of IR and NMR spectrometers. Viscometric measurements were done by metal–polymer complexes with Cu(II), Ni(II), and Cd(II) in aqueous solution at 25°C and Ni(II) was found to be the most effective ion in decreasing the viscosity of the polymer solution than the other two metal ions, whereas Cd(II) was the least effective cation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2262–2265, 2004
Preparation and characterization of SMA(SAN)/silica hybrids derived from water glass
Authors: Shen Liang , Zhong Wei , Wang Haitao , Du Qiangguo , Yang Yuliang
Published: June 2004

Poly(styrene‐co‐maleic anhydride) (SMA)/silica and poly(styrene‐co‐acrylonitrile) (SAN)/silica hybrids were prepared via a sol‐gel route by using silicic acid oligomer (SAO) from water glass in this article. This convenient route is different from the traditional one from tetraethoxysilane (TEOS). The polycondensation behavior of the SAO and the aggregation behavior of the silica particles in the hybrids were investigated. The prepared SMA(SAN)/silica hybrids were characterized by infrared spectroscopy, dynamic light scattering, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The results showed that the particle size of silica in hybrids increased with increasing silica loading and decreased dramatically by adding the coupling agents. The decomposition temperature and the glass‐transition temperature of the hybrids were higher than the precursory polymers. The mechanical properties of blends of acrylonitrile‐butadiene‐styrene copolymers (ABS) resin with the hybrids were also tested and the results indicated that the well‐dispersed silica particles in the hybrids indeed reinforced the blends. Some nanocomposites based on ABS were prepared in this way. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2289–2296, 2004
Bone cell viability on collagen immobilized poly(3‐hydroxybutrate‐co‐3‐hydroxyvalerate) membrane: Effect of surface chemistry
Authors: Tesema Y. , Raghavan D. , Stubbs J.
Published: June 2004

The effect of surface chemistry on proliferation and morphology of bone cells cultured on surface modified poly(3‐hydroxybutrate‐co‐3‐hydroxyvalerate) (PHBV) and untreated PHBV was evaluated. The surface of cast PHBV film was physically and chemically immobilized with collagen. For preparing chemically immobilized collagen surface, PHBV film was ozone treated followed by grafting of PMAA chains and the immobilization of collagen. The surface roughness and hydrophilicity of PHBV film were determined by atomic force microscopy (AFM) and contact angle measurements, respectively. It was found that the duration of ozone exposure and monomer concentration used for grafting PMMA chains influenced the amount of collagen immobilized. The cell proliferation on PHBV surfaces with chemically and physically immobilized collagen was compared with untreated PHBV using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay. The bone cell activity on chemically and physically immobilized collagen PHBV films was found to be 246 and 107% for UMR‐106 and 68 and 9% for MC3T3 cell lines, respectively. Although the results are very preliminary, the chemically grafted collagen on PHBV surface provided a favorable matrix for cell proliferation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2445–2453, 2004
Method for induction time determination using data obtained from isothermal crystallization experiment monitored by DSC
Authors: Šipušić J. , Kurajica S. , Bezjak A.
Published: June 2004

Previously introduced method for transforming kinetic function expression was applied on the differential form of isothermal Johnson–Mehl–Avrami (JMA) nucleation and growth equation, to determine the duration of the induction period, τ. The assisting function φ = tm was used to obtain a new equation, which enables determination of the induction time, τ, along with the Avrami parameter, n. The procedure was tested using a developed computer program on simulated data, experimental poly(ethylene‐terephtalate) (PET) cold crystallization data, and poly(ester‐urethane) polycaprolactone‐diol polymer (PEU) crystallization data obtained from literature. The test results show the validity of developed equations and their applicability for the determination of kinetic parameters, particularly the induction time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2454–2458, 2004
Filamentous green algae additions to isocyanate based foams
Authors: Johnson M. , Shivkumar S.
Published: June 2004

Filamentous green algae, Cladophora glomerata, obtained from rivers and streams in California was used as a filler in isocyanate‐based foams. Up to 40 wt % dried and chopped algal fibers were added to the isocyanate–polyol mix. The algal fibers and foam samples were examined by scanning electron microscopy. The effective hydroxyl number of the algae and the tensile and compressive properties of the composite foam were measured. The results indicate that foams with a uniform cell size were obtained for algal fiber lengths between 500 and 600 μm. Peak mechanical properties were obtained for algae concentrations between 5 and 10 wt %. The elastic modulus of the foam follows a power law relationship with density, with an exponent of 1.6. The overall hydroxyl number for the algae is around 300. The hydroxyl groups in the algae can serve as efficient sites for reactions with isocyanate and hence algae fibers can act as reinforcing fillers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2469–2477, 2004
Mechanical properties of biorenewable fiber/plastic composites
Authors: Julson James L. , Subbarao Gurram , Stokke D. D. , Gieselman Heath H. , Muthukumarappan K.
Published: June 2004

Plastic fiber composites, consisting of polypropylene (PP) or polyethylene (PE), and pinewood, big blue stem (BBS), soybean hulls, or distillers dried grain and solubles (DDGS), were prepared by extrusion. Young's modulus, tensile and flexural strengths, melt flow, shrinkage, and impact energy, with respect to the type, amount, and size of fiber on composites, were evaluated. Young's moduli under tensile load of wood, BBS, and soybean‐hull fiber composites, compared with those of pure plastic controls, were either comparable or higher. Tensile strength significantly decreased for all the PP/fiber composites when compared with that of the control. Strength of BBS fiber composites was higher than or comparable to that of wood. When natural fibers were added there was a significant decrease in the melt flow index for both plastic/fiber composites. There was no significant difference in the shrinkage of all fiber/plastic composites compared to that of controls. BBS/PE plastic composites resulted in higher notched impact strength than that of wood or soybean‐hull fiber composites. There was significant reduction in the unnotched impact strength compared to that of controls. BBS has the potential to be used as reinforcing materials for low‐cost composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2484–2493, 2004
Porous magnetic chelator support for albumin adsorption by immobilized metal affinity separation
Authors: Odabašı Mehmet , Uzun Lokman , Denizli Adil
Published: June 2004

Magnetic poly(2‐hydroxyethylmethacrylate) (mPHEMA) beads are modified by iminodiacetic acid (IDA) to implify the reactive groups and subsequent binding of Cu2+ ions to form metal chelate. mPHEMA beads, in the size range of 80–120 μm, were produced by a modified suspension polymerization technique. mPHEMA beads were characterized by swelling tests, electron spin resonance (ESR), FTIR, and scanning electron microscopy (SEM). Important results obtained in this study are as follows. The swelling ratio of mPHEMA beads was 34%. The presence of magnetite particles in the polymeric structure was confirmed by ESR. FTIR data confirmed that the magnetic polymer beads were modified with functional groups IDA. The mPHEMA beads have a spherical shape and porous structure. The effect of pH and concentration of human serum albumin (HSA), on the adsorption of HSA to the metal‐chelated magnetic beads, were examined in a batch reactor. Most importantly, the magnetic beads had little nonspecific adsorption for HSA (0.5 mg/g) before introducing IDA groups. Cu2+ chelation increased the HSA adsorption up to 28.4 mg/g. Adsorption behavior can be described at least approximately with the Langmuir equation. Regeneration of the metal‐chelated magnetic beads was easily performed with 1.0M NaSCN, pH 8.0, followed by washing with distilled water and reloading with Cu2+. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2501–2510, 2004
Selecting areas to protect the biodiversity of aquatic ecosystems in a semiarid Mediterranean region using water beetles
Authors: Sánchez‐Fernández D. , Abellán P. , Velasco J. , Millán A.
Published: June 2004

In this work, carried out in the province of Murcia, a representative semi‐arid area of the Iberian Peninsula, water beetles were used as indicators to identify the aquatic ecosystems with the highest interest for conservation. For that purpose, an iterative algorithm of complementarity based on the richness of aquatic Coleoptera was applied. ‘Complementarity’ refers to the degree to which an area, or set of areas, contributes otherwise unrepresented attributes to a set of areas. This principle was used to maximize the number of species represented within a given number of areas.

Only the species subsets whose taxonomic status, presence and distribution in the study area are well known were used. In total, 146 species were included, of which 12 are Iberian endemics and 32 are rare species (found only in one grid cell in the study area).

The highest correlation was generally shown by species richness with endemic, rare and vulnerable species richness. Thus, basing conservation strategies on species richness appears to be an effective protocol.

To preserve the highest degree of biodiversity in the aquatic ecosystems of the study area, the following need to be protected: (a) headwater streams in the north west of the province; (b) the uppermost reaches of the Segura River; (c) hypersaline and coastal ramblas; (d) rock pools and coastal ponds.

The present network of Protected Natural Spaces in the study area does not include many of the aquatic ecosystems shown to have the highest biodiversity of beetles. However, the future European ‘Natura 2000’ network will protect the 10 grid cells of highest aquatic biodiverstity, or at least part of them.

Copyright © 2004 John Wiley & Sons, Ltd.
A digenic cause of cleft lip in A‐strain mice and definition of candidate genes for the two loci
Authors: Juriloff Diana M. , Harris Muriel J. , Dewell Sarah L.
Published: June 2004

BACKGROUND

Nonsyndromic cleft lip with or without cleft palate, CL(P), is a common human birth defect with a complex unknown genetic cause. The mouse model is the “A/∼” strains. Our previous studies mapped two loci:clf1on Chr11 andclf2on Chr13—with a strong genetic maternal effect on the level of risk. Here we test the hypothesis that CL(P) is digenic and identify candidate genes forclf1andclf2.

METHODS

We observed E14 CL(P) frequencies in backcross (BC1) embryos from a new cross of A/WySn to AXB‐4/Pgn and from test crosses of three new “congenic RI” lines. Using new polymorphic markers from genes and our mapping panels of segregants and RI strains, we identified the candidate genes forclf1andclf2. We sequenced the coding region ofPtchin A/WySn cDNA.

RESULTS

Seventy new BC1 CL(P) segregants (4%) were obtained, as predicted. All three new congenic RI lines homozygous for bothclf1andclf2had A/WySn‐level CL(P) frequencies (10–30%) in test crosses. Theclf1region contains 10 known genes (Arf2,Cdc27,Crhr1,Gosr2,Itgb3,Mapt,Myl4,Nsf,Wnt3, andWnt9b). Theclf2region contains 17 known genes with human orthologs. Both regions contain additional potential genes. No causal mutation inPtchcoding sequence was found.

CONCLUSIONS

In A‐strain mice, nonsyndromic CL(P) is digenic, suggesting that nonsyndromic human CL(P) may also be digenic. The orthologous human genes are on 17q (clf1) and 9q, 8q and 5p (clf2), and good candidate genes areWNT3orWNT9B(17q), andPTCH(9q) orMTRR(5p). Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
The interaction of water molecules with purple membrane suspension using 2H double‐quantum filter, 1H and 2H diffusion nuclear magnetic resonance
Authors: Frish Limor , Friedman Noga , Sheves Mordechai , Cohen Yoram
Published: June 2004

Bacteriorhodopsin is a membrane protein of the purple membrane (PM) of Halobacterium salinarum, which is isolated as sheets of highly organized two‐dimensional hexagonal microcrystals and for which water molecules play a crucial role that affects its function as a proton pump. In this paper we used single‐ and double‐quantum 2H NMR as well as 1H and 2H diffusion NMR to characterize the interaction of water molecules with the PM in D2O suspensions. We found that, under the influence of a strong magnetic field on a concentrated PM sample (0.61 mM), the PM sheets affect the entire water population and a residual quadrupolar splitting (υq ∼5.5 Hz, 298 K, at 11.7 T) is observed for the D2O molecules. We found that the residual quadrupolar coupling, the creation time in which a maximal DQF signal was obtained (τmax), and the relative intensity of the 2H DQF spectrum of the water molecules in the PM samples (referred to herein as NMR order parameters) are very sensitive to temperature, dilution, and chemical modifications of the PM. In concentrated PM samples in D2O, these NMR parameters seem to reflect the relative organization of the PM. Interestingly, we have observed that some of these parameters are sensitive to the efficiency of the trimer packing, as concluded from the apo‐membrane behavior. The data for dionized blue membrane, partially delipidated sample, and detergent‐treated PM show that these D2O NMR order parameters, which are magnetic field dependent, are sensitive to the structural integrity of the PM. In addition, we revealed that heating the PM sample inside or outside the NMR magnet has, after cooling, a different effect on the NMR characteristics of the water molecules in the concentrated PM suspensions. The difference in the D2O NMR order parameters for the PM samples, which were heated and cooled in the presence and in the absence of a strong magnetic field, corroborates the conclusions that the above D2O order parameters are indirect reflections of both microscopic and macroscopic order of the PM samples. In addition, 1H NMR diffusion measurements showed that at least three distinct water populations could be identified, based on their diffusion coefficients. These water populations seem to correlate with different water populations previously reported for the PM system. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Process development for degradation of phenol by Pseudomonas putida in hollow‐fiber membrane bioreactors
Authors: Chung Tsuey‐Ping , Wu Pei‐Chen , Juang Ruey‐Shin
Published: June 2004

The degradation of phenol (100‐2800 mg/L) by cells Pseudomonas putida CCRC14365 in an extractive hollow‐fiber membrane bioreactor (HFMBR) was studied, in which the polypropylene fibers were prewetted with ethanol. The effects of flow velocity, the concentrations of phenol, and the added dispersive agent tetrasodium pyrophosphate on phenol degradation and cell growth were examined. It was shown that about 10% of phenol was sorbed on the fibers at the beginning of the degradation process. The cells P. putida fully degraded 2000 mg/L of phenol within 73 h when the cells were immobilized and separated by the fibers. Even at a level of 2800 mg/L, phenol could be degraded more than 90% after 95‐h operation. At low phenol levels (< 400 mg/L) where substrate inhibition was not severe, it was more advantageous to treat the solution in a suspended system. At higher phenol levels (> 1000 mg/L), however, such HFMBR‐immobilized cells could degrade phenol to a tolerable concentration with weak substrate‐inhibition effect, and the degradation that followed could be completed by suspended cultures due to their larger degradation rate. The process development in an HFMBR system was also discussed. © 2004 Wiley Periodicals, Inc.
Gelation conditions and transport properties of hollow calcium alginate capsules
Authors: Chai Yi , Mei Le‐He , Wu Guo‐Liang , Lin Dong‐Qiang , Yao Shan‐Jing
Published: June 2004

The diameter, membrane thickness, and compression intensity of hollow Ca‐alginate capsules were measured at different gelation conditions, such as the reactant concentration, dropping velocity, and gelation time. The optimum operation conditions for preparing capsules were determined at 100 g/L CaCl2, 10 g/L sodium alginate (Na‐alginate), a dropping velocity of 150 droplets/min, and a gelation time of 10 min. Diffusion of some saccharide and amino acid from bulk solution into capsules was investigated, and the diffusion coefficients were calculated by the developed mathematical model. All the tested substances can diffuse easily into the capsules. The combined diffusion coefficients of the capsule Dm are 92–99% as large as their diffusion coefficients in pure water, while the diffusion coefficients in the capsule membrane D1 are 60–95% as large as those. By employing polyethylene glycol (PEG) and bovine serum albumin (fraction V) (BSA(V)), the molecular weight cut‐off of the capsule was determined. For linear macromolecules, hollow Ca‐alginate capsules have a molecular weight cut‐off of 4,000. No diffusion of BSA(V) into the capsules was observed. © 2004 Wiley Periodicals, Inc.
Marine Darwinfinken und schwarze Pilze
Authors: Kaselowsky Jürgen , Hamamoto Makiko , Nagahama Takahiko , Scholz Joachim , Sterflinger Katja
Published: June 2004

Von der Tiefsee, die ein größeres Areal einnimmt als sämtliche Kontinente der Erde, ist eine Fläche erforscht, die nicht einmal halb so groß ist wie die Stadt Venedig. Zu den zahlreichen nur wenig oder noch gänzlich unbekannten Organismen zählen auch die Bryozoen (Moostierchen) und die häufig auf ihnen wachsenden Pilze.
Meilenstein der Molekularbiologie: Das „Avery‐Experiment”︁
Authors: Scherr Michaela , Scherr Dietmar
Published: June 2004

Die Experimente von T. O. Avery bestätigten 1943/44 die transformierenden Eigenschaften von DNA. Wir beschreiben hier ein einfaches Experiment für die Schule, um Bakterien mit Plasmiden zu transformieren und das transformierende Prinzip zu beobachten. Es ermöglicht den Schülerinnen und Schülern ein grundlegendes Verständnis der modernen molekularen Genetik.