bluuebunny/crossref_metadata_2025 huggingface dataset:
Probe Systems for W7‐X
Authors: Laux M. , Grigull P. , Greve H. , Reichert A. , Sachtleben J. , Ye M.
Published: June 2006

The new large stellarator W7‐X equipped with a divertor is currently under construction in the Greifswald branch of the Max‐Planck‐Institute for Plasma Physics. It is planned to begin the plasma operation with a variety of diagnostics to analyse the expected properties of the concept and explore the capabilities of the new machine. In the framework of divertor and edge plasma diagnostics a number of electrical probes will be exposed to monitor particle fluxes, electron temperatures and potentials in the vicinity of the divertor targets as well as up‐stream. W7‐X is intended to operate in quasi‐stationary regime with a large power input. The open island divertor has to handle the high particle fluxes and the peak power flux to the targets. Consequently, fast movable mechanisms are designed to cyclically expose and retract the probes. Four pneumatically driven arrays of single probe tips are planned for the horizontal and vertical parts of one upper and lower divertor module, respectively. The probe tips are designed to avoid the problem of shallow angles with the magnetic field, to tolerate the impinging power, to be adjustable in their radial position and exchangeable without dismounting the targets. Additionally, a small number of basically identical linear manipulators are planned for different locations around the stellarator with exchangeable diagnostic heads (fast moving probe, Mach probes, emissive probes, retarding field analysers, collector probes, etc). The main design problems of the probe systems and results from prototype tests are reported. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐Situ Method of Monitoring Argon Plasma Density Variation Using Current and Voltage of Flat Antenna in Inductively Coupled Plasma Source
Authors: Lee S.‐H. , Cho J.‐H. , Kim G.‐H.
Published: June 2006

The in‐situ monitoring method of plasma density variation in the inductively coupled plasma (ICP) source was developed with the air‐core transformer model using the current and voltage of antenna. The model was modified for the ICP generated by the flat antenna. The collision effect was also considered to obtain the skin depth and plasma impedance. Monitored plasma density was compared to the probe data taken at the center of chamber, showing the good agreement in the density variation with various powers of 100 to 1500 W and the argon operating pressures of 7 to 100 mTorr, respectively. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of Langmuir Probe and Laser Thomson Scattering Methods in the Electron Temperature Measurement in Divertor Simulator MAP‐II
Authors: Okamoto A. , Kado S. , Iida Y. , Tanaka S.
Published: June 2006

In order to investigate details of anomaly in the Langmuir probe current (I)‐voltage (V) characteristics, electron temperatures and densities are measured by both Langmuir probe and laser Thomson scattering methods. The electron densities measured with both methods show good agreement in hydrogen‐molecular assisted recombination (H2‐MAR) plasmas. On the other hand, the electron temperatures measured with Langmuir probe are overestimated compared with that obtained from the Thomson scattering spectrum in the H2‐MAR plasmas. Histogram of electron current deviated from its average shows that fluctuation appeared in the electron current becomes large and the histogram distorted in temperature‐overestimated condition, especially when the probe voltage is negatively biased. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurements of Directional Flow Using a Directional Langmuir Probe in Weakly Magnetized Plasmas
Authors: Shikama T. , Kado S. , Okamoto A. , Tanaka S.
Published: June 2006

Measurement of flow directed with respect to the magnetic field is performed using a directional Langmuir probe (DLP). A previously proposed practical formula for measurement of the Mach number under a weakly magnetized condition is modified for application to the directional flow field which consists of parallel and azimuthal flow components. The effect of density gradient caused by the rotational DLP measurement in the measurement of the radial profile of ion current angular distribution is modified. For the verification of the DLP measurement, parallel flow velocity is measured from the Doppler shift of HeII emission, while azimuthal flow velocity is calculated from E × B and diamagnetic drifts. It is revealed that this method provides plausible Mach numbers in the parallel and azimuthal directions with inclusion of the effect of density gradient. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurement of Reynolds Stress and Zonal Flows in a Tokamak Using Langmuir Probe Array
Authors: Xu G. S. , Wan B. N.
Published: June 2006

The Reynolds stress and zonal flows have been measured with several novel Langmuir probe array on the HT‐7 tokamak since the year 2002. Based on the original idea of the Reynolds stress triple tips array, we designed the forked probe and its improved generation, the farmer fork probe. And in order to measure the radial shearing rate of zonal flows, we designed the pyramid probe in 2003. Besides, an insert‐able magnetic probe was elaborated to measure the Maxwell stress in 2003. This paper addresses the technique aspects regarding this new application. Since the zonal flows dynamics is now widely believed crucial to plasma confinement physics, this opened up an important application field of Langmuir probe. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of Plasma Density and Temperature from Intensity Ratios of He I Emission Lines in Diversified Plasma Simulator (DiPS)
Authors: Jung Y. H. , Yoon J.‐S. , Yoo S. J. , Kim Y.‐W. , Lho T. , Lee B. , Do J.‐J. , Woo H.‐J. , Chung K.‐S.
Published: June 2006

The intensity ratios of He I emission lines are used to determine electron density and temperature in Diversified Plasma Simulator (DiPS). The HeI line ratios are measured by optical emission spectroscopy and are calculated using the collisional‐radiative equilibrium (CRE) model. The measured He I line ratios are 706.52 nm / 728.13 nm for electron temperature and 728.13 nm / 667.82 nm for electron density determination, respectively. The results obtained from the collisional‐radiative equilibrium model are crosschecked with those of electrical probe measurement. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Cationic (N‐Heterocyclic carbene)silver Complex as Catalyst for Bulk Ring‐Opening Polymerization ofL‐Lactides
Authors: Samantaray Manoja K. , Katiyar Vimal , Roy Dipankar , Pang Keliang , Nanavati Hemant , Stephen Raji , Sunoj Raghavan B. , Ghosh Prasenjit
Published: June 2006

Synthetic, theoretical, and catalysis studies of a cationic functionalized N‐heterocyclic carbene complex of silver, namely[{1‐isopropyl‐3‐(N‐phenylacetamido)imidazol‐2‐ylidene}2Ag]+Cl–(1b), is reported. Specifically,1bwas synthesized by the reaction of 1‐isopropyl‐3‐(N‐phenylacetamido)imidazolium chloride (1a) with Ag2O in 64 % yield;1awas synthesized by the alkylation reaction of 1‐isopropylimidazole withN‐phenyl chloroacetamide in 90 % yield. The molecular structure of1bwas determined by X‐ray diffraction studies and was found to be active for polymerization ofL‐lactide at elevated temperatures under solvent‐free melt conditions to give polylactide of moderate molecular weight with narrow molecular weight distribution. Density functional theory studies of the cationic species2b, derived from NHC silver complex1b, were employed to obtain an understanding of the structure, bonding, and electronic features of the molecule. Bonding in complex2bhas been probed with the help of charge decomposition analysis (CDA), the atoms in molecules (AIM) approach as well as natural bond orbital (NBO) methods. The Ag–NHC bond has been found to be more covalent with NHC acting as an effective σ‐donor. The π‐back‐bonding from the metal atom to the ligand was found to be negligible. It has been noticed that the imidazole rings remain nearly orthogonal with respect to each other, in contrast to the experimental geometry. Intramolecular hydrogen bonds as well as Ag···O interaction involving the carbonyl oxygen atoms have been identified as additional stabilizing factors contributing towards the lower energy conformer of2bcompared to the corresponding planar geometry.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of Ionic Liquid Functionalized SBA‐15 Mesoporous Materials as Heterogeneous Catalyst toward Knoevenagel Condensation under Solvent‐Free Conditions
Authors: Liu Yong , Peng Jiajian , Zhai Shangru , Li Jiayun , Mao Jianjiang , Li Meijiang , Qiu Huayu , Lai Guoqiao
Published: June 2006

1‐Methyl‐3‐propylimidazolium chloride (MPImCl) and 1‐propylpyridinium chloride (PPyCl) ionic liquid functionalized SBA‐15 mesoporous materials were synthesized and used as heterogeneous catalysts in Knoevenagel reactions with excellent yields and reusability. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
6‐Deoxy‐α‐L‐talopyranosides from Streptomyces sp.
Authors: Bitzer Jens , Zeeck Axel
Published: June 2006

Streptomyces sp. strain GöM1 was found to produce seven novel glycosides (2–8) containing the rare deoxysugar 6‐deoxy‐α‐L‐talose. The aglycones are small phenols, isovaleric acid or aromatic carboxylic acids. By precursor‐directed biosynthesis, the yields of the compounds could be increased significantly. Feeding of 4‐hydroxybenzoic acid led to the production of both acyl and aryl glycosides, and of compound 9 with both structural elements. Pyrrol‐2‐ylcarbonyl 6‐deoxy‐α‐L‐talopyranoside (6) shows remarkable growth inhibition of some parasites. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
New Way to Methylene‐2H‐azirines and Their Use as Powerful Intermediates for the Stereo‐ and Regioselective Synthesis of Compounds with Vinylamine Substructure
Authors: Fotsing Joseph Rodolph , Banert Klaus
Published: June 2006

New and relatively stable methylene‐2H‐azirines 1 have been prepared by photolysis of allenyl azides or from 2‐halo‐2H‐azirines by elimination of HX (X = halogen). The reaction of these methylene‐2H‐azirines with nucleophiles led to the highly stereo‐ and regio‐selective formation of novel 1‐aminovinyl derivatives with good to excellent yields. The trapping reactions of the less stable methylene‐2H‐azirines gave rise to similar results. Moreover, we were able to prove that the previous report on 2‐(phenylsulfonyl)acrylonitrile (9) was based on incorrect data. For this reason, the latter compound can be supposed to be firstly described in this paper. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
5‐aminoimidazole‐4‐carboxamide‐1‐beta‐4‐ribofuranoside attenuates experimental autoimmune encephalomyelitis via modulation of endothelial–monocyte interaction
Authors: Prasad Ratna , Giri Shailendra , Nath Narender , Singh Inderjit , Singh Avtar K.
Published: June 2006

Experimental autoimmune encephalomyelitis (EAE) is a model for studying multiple sclerosis (MS), a chronic demyelinating disorder of the CNS. 5‐Aminoimidazole‐4‐carboxamide ribonucleoside (AICAR), an activator of AMP‐activated protein kinase (AMPK), has been reported to show antiinflammatory and immunomodulatory effects in various models of inflammation. Recently, we have reported AICAR‐mediated attenuation of active and passive EAE in mouse model [Nath et al. (2005) J. Immunol. 175:566–574]. Here we used a rat model of acute EAE to show antiinflammatory effects of AICAR after daily treatment starting at onset of the disease. By maintaining the blood–brain barrier (BBB), AICAR‐administered animals showed lower clinical scores compared with untreated EAE animals. AICAR inhibited the infiltration of inflammatory cells across the BBB, resulting in lowered expression of proinflammatory mediators in the CNS and protection from severe demyelination. By using in vitro model of endothelial–leukocyte interaction, we showed that AICAR inhibited adhesion of monocytes to tumor necrosis factor‐α‐activated endothelial cells. One of the mechanisms of this action is through down‐regulation of expression of endothelial cell adhesion molecules via modulation of nuclear factor κB activation. The data suggest that AICAR attenuates EAE progression by limiting infiltration of leukocytes across the BBB, thereby controlling the consequent inflammatory reaction in the CNS. © 2006 Wiley‐Liss, Inc.
Decreased expression of brain‐derived neurotrophic factor in BDNF+/− mice is associated with enhanced recovery of motor performance and increased neuroblast number following experimental stroke
Authors: Nygren Josefine , Kokaia Merab , Wieloch Tadeusz
Published: June 2006

Brain‐derived neurotrophic factor (BDNF) is involved in brain plasticity and neuronal survival. Generally, BDNF enhances synaptic activity and neurite growth, although the effect of BDNF on neuronal survival and brain plasticity following injury is equivocal. Housing rats in an enriched environment after experimental stroke enhances recovery of sensory‐motor function, which is associated with a decrease in the BDNF mRNA and protein levels. We used BDNF+/− mice and wild‐type littermate mice to investigate whether the decrease in the brain levels of BDNF affected motor function or infarct volume following transient occlusion of the middle cerebral artery (tMCAO) for 40 min. We found that the BDNF+/− mice had a significantly improved motor function on the rotating pole test 2 weeks after tMCAO compared with wild‐type mice. When intermittently exposed to an enriched environment following tMCAO, the wild‐type mice improved motor function to the same degree as BDNF+/− mice. There was no effect of BDNF reduction on infarct volume. Neurogenesis is induced following experimental stroke, and in the striatum of BDNF+/− mice significantly increased numbers of neuroblasts compared with wild‐type mice were seen, both in standard and in enriched conditions. We conclude that decreasing brain levels of BDNF enhances the recovery of function following experimental stroke. © 2006 Wiley‐Liss, Inc.
Ethanol exposure during embryogenesis decreases the radial glial progenitorpool and affects the generation of neurons and astrocytes
Authors: Rubert Gemma , Miñana Rosa , Pascual Maria , Guerri Consuelo
Published: June 2006

Prenatal ethanol exposure induces functional abnormalities during brain development affecting neurogenesis and gliogenesis. We have previously reported that alcohol exposure during embryogenesis disrupts radial glia (RG) and gliogenesis. Taking into account the new role of RG as neural progenitors, we have investigated whether ethanol affects RG as a neural stem cell. We found that in utero ethanol exposure impairs cell proliferation and decreases neurons and astrocytes generated in cultured RG and in embryonic cerebral cortex. Telencephalic cultures obtained at E12 from ethanol‐treated rats displayed a reduction in the proportion of actively dividing RG progenitors, as demonstrated by 5‐bromo‐2′‐deoxyuridine incorporation, and in the percentage of brain lipid binding protein‐positive RG. Consistently, neurosphere formation assay from E12 telencephalon showed a reduced number of multipotent progenitor cells in cultures isolated from ethanol‐treated rats in comparison with pair‐fed control group. Moreover, levels of activated Notch1 and fibroblast growth factor receptor 2, which regulate the maintenance of the progenitor state of RG, are decreased by prenatal ethanol exposure. These findings demonstrate that ethanol reduces the telencephalic RG progenitor pool and its transformation into neurons and astrocytes, which may contribute to an explanation of the defects in brain function often observed in fetal alcohol syndrome. © 2006 Wiley‐Liss, Inc.
Intraoperative passive kinematics of osteoarthritic knees before and after total knee arthroplasty
Authors: Siston Robert A. , Giori Nicholas J. , Goodman Stuart B. , Delp Scott L.
Published: June 2006

Total knee arthroplasty is a successful procedure to treat pain and functional disability due to osteoarthritis. However, precisely how a total knee arthroplasty changes the kinematics of an osteoarthritic knee is unknown. We used a surgical navigation system to measure normal passive kinematics from 7 embalmed cadaver lower extremities and in vivo intraoperative passive kinematics on 17 patients undergoing primary total knee arthroplasty to address two questions: How do the kinematics of knees with advanced osteoarthritis differ from normal knees?; and, Does posterior substituting total knee arthroplasty restore kinematics towards normal? Osteoarthritic knees displayed a decreased screw‐home motion and abnormal varus/valgus rotations between 10° and 90° of knee flexion when compared to normal knees. The anterior–posterior motion of the femur in osteoarthritic knees was not different than in normal knees. Following total knee arthroplasty, we found abnormal varus/valgus rotations in early flexion, a reduced screw‐home motion when compared to the osteoarthritic knees, and an abnormal anterior translation of the femur during the first 60° of flexion. Posterior substituting total knee arthroplasty does not appear to restore normal passive varus/valgus rotations or the screw motion and introduces an abnormal anterior translation of the femur during intraoperative evaluation. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1607–1614, 2006
Histological comparison of the dorsal ordinary muscles of wild and full‐cycle cultured Pacific bluefin tuna (Thunnus orientalis)
Authors: Nakamura Yoshi‐Nori , Ando Masashi , Seoka Manabu , Kawasaki Ken‐ichi , Tsukamasa Yasuyuki
Published: June 2006

The histological properties of the cephalad parts of the dorsal ordinary muscles (CD‐OMs) of wild (body weight 33.3 ± 0.9 kg, n = 3) and full‐cycle cultured (body weights 13.1 ± 2.6 (FC 1), 20.2 ± 1.0 (FC 2) and 28.5 ± 3.6 (FC 3) kg, n = 3 respectively) Pacific bluefin tuna were investigated. The CD‐OMs of FC 1–3 tuna showed low moisture content (P < 0.05) and high fat content (about six times more, P < 0.05) in comparison with wild fish. A large quantity of adipose tissue was observed in the wide spaces between muscle fibres in the CD‐OMs of FC 1‐3 tuna. The muscle fibre diameter of the CD‐OM of FC 3 tuna was significantly lower than that of wild fish (P < 0.05). Myofibrils in the CD‐OM of wild tuna were surrounded by a developed sarcoplasmic reticulum and mitochondria; however, there were many glycogen granules among the myofibrils and a large quantity of fat in the CD‐OM of full‐cycle cultured fish. In particular, the glycogen content of the CD‐OM of FC 3 tuna was significantly higher (about 50 times) than that of wild fish. These results indicate that feeding and exercise conditions affect the histological structure and metabolism of the bluefin tuna muscle. Copyright © 2006 Society of Chemical Industry
Starch but not protein digestibility is altered in pigs fed transgenic peas containing α‐amylase inhibitor
Authors: Collins Cherie L , Eason Paul J , Dunshea Frank R , Higgins Thomas JV , King Ray H
Published: June 2006

Eighteen individually housed boars were randomly allocated to one of three dietary treatments, an experimental wheat diet containing 989.4 g kg−1of a basal wheat diet, or this experimental wheat diet with 500 g kg−1of the basal wheat diet replaced with 500 g kg−1of either transgenic or non‐transgenic peas. The transgenic peas expressed the bean (Phaseolus vulgarisL.) α‐amylase inhibitor 1 gene. Diets containedn‐hexatriacontane (0.2 g kg−1) as an indigestible marker to allow the determination of nutrient digestibility at the terminal ileum. Pigs were offered 1.6 kg day−1for 15 days, after which they were anaesthetised, the ileal and faecal digesta collected and the pigs subsequently euthanased. The ileal dry matter and starch digestibilities of the experimental wheat, non‐transgenic and transgenic pea diets were 78.3, 74.2 and 45.8% and 95.9, 95.2 and 42.4%, respectively. The apparent nutrient digestibilities of the non‐transgenic and transgenic peas were determined by difference. The ileal dry matter digestibility was significantly reduced in the transgenic peas compared with the non‐transgenic peas (12.7 and 69.9%, respectively;P= 0.006), which was largely due to a reduced starch digestibility. The apparent crude protein digestibilities of the transgenic peas were similar to the non‐transgenic, being 79.7 and 78.5%, respectively. The amino acid digestibilities of the transgenic and non‐transgenic peas were also similar. Copyright © 2006 Society of Chemical Industry
Thermal, Rheological, and Mechanical Behaviors of LLDPE/PEMA/Clay Nanocomposites: Effect of Interaction Between Polymer, Compatibilizer, and Nanofiller
Authors: Zhang Mingqian , Sundararaj Uttandaraman
Published: June 2006

Summary: Linear low density polyethylene/maleic anhydride grafted polyethylene/montmorillonite clay (LLDPE/PEMA/clay) nanocomposites prepared using a co‐rotating twin screw extruder exhibit unique thermal, rheological, and mechanical behaviors. All the mechanical properties including ductility increase with clay loading. X‐ray diffraction analysis and TEM images reveal an intercalated clay structure for the LLDPE/PEMA/clay composite with 5% clay and an exfoliated structure for that with 2% clay. Differential scanning calorimetry shows that the addition of PEMA does not influence the melting temperature but favors the formation of more thin lamellas. Rheological characterization indicates that the LLDPE‐PEMA blend has similar rheological behavior to neat LLDPE, implying the two polymers are completely miscible. The composites exhibit significantly higher storage and loss modulus and complex viscosity at low frequencies, and the magnitude of all these properties increases with clay loading. Furthermore, the slopes of G′, G″, and complex viscosity versus frequency are similar for the composites of different phase morphologies, suggesting that the rheological behaviors of the composites depends more on clay loading than phase morphology. The enhanced miscibility between LLDPE and PEMA, and more importantly, interfacial interaction between clay, PEMA, and LLDPE, are responsible for the distinct improvement in all the mechanical properties of the composite, and in particular for the marked improvement in ductility.

Stress‐strain diagram for LLDPE, LLDPE/PEMA, and LLDPE/PEME‐clay nanocomposites.

magnified image

Stress‐strain diagram for LLDPE, LLDPE/PEMA, and LLDPE/PEME‐clay nanocomposites.
Use of Thermoplastic Starch in Continuous Pharmaceutical Process
Authors: Keszei Sándor , Szabó András , Marosi Gyürgy , Anna Péter , Nagy Sándor
Published: June 2006

Controlled release formulations of thermoplastic starch (TPS) matrix were prepared by extrusion granulation and injection molding of tablets. The compositions contained glycerol, water and on occasion urea plasticizers, glycerol‐monostearate; Ca‐stearate lubricants and Na‐benzoate drug representing component, in addition to the starch. The lubricants and especially the urea reduce the complex viscosity of the TPS considerably facilitating the injection molding process‐ability. DSC thermal analysis demonstrated, the urea is in a molecular dispersed form in the extruded granules and Raman microscopic mapping showed an under micron sized dispersion of Na‐benzoate in injection molded tablets. Both the extrusion and the injection molding processing resulted retard release character of the active component.
Structural Characteristics and Permeability of Ethyl Cellulose Films Containing Different Plasticizers
Authors: Fekete Rita , Marosi György , Fekete Pál , Dredán Judit , Marton Sylvia , Antal István
Published: June 2006

The effect of different type of plasticizers was investigated in ethyl cellulose as coating polymer for manufacturing coated pellets of modified release containing a water soluble model drug. Scanning electron microscopic image analysis (SEM), differential scanning calorimetry (DSC), X‐ray photoelectron spectroscopic chemical surface analysis (XPS) were used to study the films, and the dissolution profiles of coated pellets were evaluated. The effect of the different plasticizers and coating levels on the first order dissolution rate constant is determined by statistical experimental design. Correlation was found between the dissolution rate constant and the structural characteristics of the coating layer containing different plasticizers. Partial segregation of the plasticizers was detected especially on the surface of the films, which is in correlation with the differences in the glass transition temperatures. PEG 400 is found to be compatible enough to form continuous, durable EC coating at 5% concentration level, which gave the slowest dissolution.
Drug Release Study of Systems Containing the Tragacanth and Collagen Composite: Release Characterization and Viscoelastic Measurements
Authors: Kaffashi B. , Zandieh A. , Khadiv‐Parsi P.
Published: June 2006

The kinetics of water penetration and pentoxifilline release from both Tragacanth gum and Tragacanth/Collagen matrices has been examined in pure deionised water. The rheological oscillatory measurements of their gel layer obtained by swelling of the imprinted pentoxifilline‐filled polymer matrix with water have been performed. To qualify a polymer for application in drug formulation, appropriate gel stiffness is required. The aqueous solution of Tragacanth does not seem to acquire the actual strength that a hydrogel must retain for this purpose. Thus, along with Tragacanth, gelatin, CaCl2 and 1, 8 octandiamine curing agent were individually blended in a mixture with Tragacanth gum to improve the gel behavior and drug delivery of the system. The strength of the gel at the body temperature (37 °C) was studied using a cone and plate rheometer. It was found that gelatin could enhance the gel strength of Tragacanth by forming a porous composite. The drug release to an aqueous solution at room temperature was analyzed to be slower for a composite of 1:2 Tragacanth/Collagen.
A Novel Transparent Polyacetylene Bearing a Triphenylamine Moiety Prepared with a [Rh(norbornadiene)Cl]2 Catalyst
Authors: Miyasaka Atsushi , Nakamura Minoru , Mawatari Yasuteru , Orito Kazuhiko , Tabata Masayoshi
Published: June 2006

Novel soluble polyacetylenes having a triphenylamine moiety were synthesized by a [Rh(norbornadiene)Cl]2 catalyst under quite mild conditions in fairly high yields. The obtained polymer showed to have trans‐transoid sequence as the major main‐chain structure which was generated through the so‐called cis‐to‐trans isomerization was already induced even during the polymerization. The HCl doping of the polymer was resulted in the formation of the oxidized polymer where the so‐called polaron or bipolaron was produced. In addition, we found that in the case of the pristine polymer unpaired electrons mainly localized on the triphenylamine moiety as the side chain. On the other hand, after the doping the unpaired electron delocalized on the main chain of the polymer.
Comparative Study on the Collapse Transition of Poly(N‐isopropylacrylamide) Gels and Magnetic Nanoparticles Loaded Poly(N‐isopropylacrylamide) Gels
Authors: Filipcsei Genovéva , Szilágyi András , Csetneki Ildikó , Zrínyi Miklós
Published: June 2006

A novel polymer gel exhibiting simultaneous temperature and magnetic field sensitivity has been prepared and studied. Poly(N‐isopropylacrylamide) (PNIPA) and magnetic nanoparticles (magnetite, Fe3O4) loaded PNIPA gel beads with mm size and monolith gels with cm size were prepared. The dependence of swelling degree on the temperature has been studied. The effects of cross‐linking density and the presence of magnetic nanoparticles on the equilibrium swelling degree as well as on the collapse transition have been investigated. Swelling kinetic measurements were also made. By comparing the equilibrium swelling properties of PNIPA and magnetite loaded PNIPA gels it was found that the built in magnetic nanoparticles do not modify the temperature sensitivity of these gels. Within the experimental accuracy the temperature of the collapse transition was not sensitive to the presence of magnetic particles. We have compared the swelling behaviour of mm size gel beads to the cm size monolith gels in order to study the influence of surface skin layer on the swelling equilibrium. It was established that the extent of surface skin formation was decreased by the presence of magnetic particles.
Statistical Modeling of Unidirectional Fibrous Structures
Authors: Vas László M.
Published: June 2006

Some textiles such as slivers, rovings, yarns, and highly oriented polymer fibers as well as the reinforcing structure of unidirectional composites have a kind of unidirectional or quasi‐unidirectional fibrous structures. The statistical properties of their structure and strength can be modeled by using idealized fiber bundles as model elements. In this study the tensile test process of unidirectional short fiber structures is modeled for different damage types using the instantaneous fracture model and special idealized fiber bundles for gradual damages such as fiber breakage and fiber slippage. Constant fiber length and exponential fiber length distribution as extreme cases of the Erlang distributions were used for analysis. In case of exponential fiber length distribution and constant fiber breaking strain simple analytical relationships between the mean tensile strength and the fiber length were derived and compared to those for constant fiber length and written in a general form which is valid for all the damage modes discussed. The convex linear combination of the solutions for exponential fiber length distribution and constant fiber length was proposed to use for cases when the variation coefficient of the fiber length is between 0 and 1. The practical applicability of the results was demonstrated by identifying the relationship between the mean tensile strength and the average molecule mass of polypropylene fibers that made it possible to estimate the critical molecule mass and the tensile strength of the molecules without further measurements.
Curing and Physical Properties of Natural Rubber/Wood Flour Composites
Authors: Ichazo Miren Nekane , Hernández Marianela , Albano Carmen , González Jeanette
Published: June 2006

Natural rubber based composites were prepared by incorporating Wood flour of two different particle size ranges (250–300 µm) and (300–425 µm) and concentrations (15 and 30 phr) into the matrix, using a Banbury® internal mixer according to a base formulation. Curing characteristics of the samples were studied. Influence of particle size and loading of filler on the properties of the composites was analyzed. Results obtained show that the addition of wood flour to natural rubber increased scorch time and curing time and caused improvement in modulus at 300% strain and in tear properties. However, it decreased tensile strength and elongation at break. The particle size range of 300–425 µm was found to offer the best overall balance of mechanical and dynamic properties (tan δ and viscous torque). Swelling behavior of the composites in toluene was also analyzed in order to determine the rubber volume fraction and crosslinking density. Composites with the bigger particle size wood flour were found to have greater crosslinking density than the ones with smaller particle size, fact that could possibly indicate a better rubber‐filler interaction in the former. Major percentage of filler increased slightly this interaction. Water absorption behavior of the composites with wood flour reached a maximum of 12% w/w when 30 phr of filler were incorporated; nonetheless, particle size did not affect this property. The ageing study in presence of air at 70 °C revealed that natural rubber composites with wood flour maintained the same classification cell with temperature as the pure rubber. A compound with 30 phr of carbon black was prepared for comparative purposes. Results obtained were as expected. Scorch time decreased and higher values of modulus at 300% strain and tensile strength were achieved, due to strongest interaction between filler and elastomer.
Development of Hemp Fibre – PP Nonwoven Composites
Authors: Hargitai Hajnalka , Rácz Ilona , Anandjiwala Rajesh
Published: June 2006

Summary:
Nonwoven mats from hemp and polypropylene fibres in various proportions were produced and hot pressed to make composite material. The effect of hemp fibre content and anisotropy in nonwoven mats resulting from the carding technology were examined on the basis of the three‐point bending, tensile and impact properties of the resultant composite materials. Because of the hydrophilic nature and poor dimensional stability of cellulosic fibres due to swelling, the effect of water sorption on mechanical performances was also investigated. Optimal mechanical properties were achieved in composites made from 40–50% of hemp fibre by weight. As it was expected, better mechanical properties were found in the specimens cut from the composite sheets parallel to the direction of carding. A strong decrease in three point bending properties was noticed after immersing the composite samples in distilled water for 19 days, while the impact strength increased. Double carding of raw materials resulted in a decreased anisotropy in composite material.
Physical Properties of the Biodegradable Polymer Compositions Containing Natural Polyesters and their Synthetic Analogues
Authors: Dacko Piotr , Kowalczuk Marek , Janeczek Henryk , Sobota Michal
Published: June 2006

The thermal, mechanical and thermo‐mechanical properties of polymer compositions, containing synthetic biodegradable polymers i.e. polylacide (PLA) and aliphatic‐aromatic copolyester (BTA), natural biopolyester n‐PHB and its synthetic atactic analog (a‐PHB) were investigated. Thermal properties of the polymer compositions were studied by means of DSC . The compositions of various polymer weight ratio were tested. Compositions containing BTA and n‐PHB create polyphase systems, what was confirmed by DSC. In this case the two Tg and two Tm values were observed. Polymer compositions containing PLA and BTA showed different behaviours. At the BTA content up to 30 weight % only one Tg and one Tm were indicated. At the increase of the BTA content to 50% weight and above, the two Tg, and two Tm were observed. Mixtures of BTA with n‐PHB, PLA and with a‐PHB show considerably greater values of the strain (ε) in comparison with initial polymers (n‐PHB, PLA). It was found that in contrary to mixtures containing PLA, at the BTA content in the mixture with n‐PHB above 50% of weights increases not only the strain, but also the stress at break (σ). Strong increase of the ε value in PLA/a‐PHB mixtures with the content of a‐PHB above 30% of weights were observed.
Absorbency Behaviour of Vertically Positioned Nonwoven Glass Fiber Mats in Case of Two Different Resin Viscosities
Authors: Gombos Zoltán , Nagy Veronika , Koštáková Eva , Vas László Mihály
Published: June 2006

The resin absorbency of vertically positioned chopped strand mat samples was examined as a function of time with a microtensiometer type Krüss K12. With the help of a theoretical model the results of this measurement can be interpreted and evaluated. The samples of different structure (mats bonded with powder or emulsion) were compared and the impact of resin viscosity was studied and conclusions were drawn about the pore and capillary sizes in the mats. The results verified the applicability of the method and revealed the typical pore characteristics of mats and this way estimations can be made on the properties of composites.
Construction of Pre‐Deformed Shapes for Rapid Tooling in Injection Molding
Authors: Kovács József Gábor
Published: June 2006

The major issues in the development of injection molding technology include the progress in CAE and the developments in tool design methodology such as rapid tooling. The applicability of rapid tooling in injection molding was examined using unbalanced cooling to analyze the warpage and shrinkage. Moldflow Plastics Insight simulation software was used for the deformation calculations with different mold thermal conductivities. It can be concluded that the decreasing mold thermal conductivity will dramatically increase the volumetric shrinkage and the warpage as well. Because of these effects, it is of fundamental importance to compensate for the shrinkage and warpage, so in the paper a new design methodology is suggested for rapid tooling, which is based on the pre‐deformed model.
Aromatic Polyamides Containing Pendent Acetoxybenzamide Groups
Authors: Sava Ion , Bruma Maria
Published: June 2006

Polycondensation reaction of 5‐(4‐acetoxy‐benzamide) isophthaloylchloride with different aromatic diamines gave a series of polyisophthalamides with good solubility in organic solvents. These polymers showed good thermal stability with initial decomposition temperature above 300 °C and glass transition temperature in the range of 220–335 °C. Thin, flexible, transparent films were cast from solutions, having good electroinsulating properties.
Interaction of Maleic Acid Copolymers with Collagen
Authors: Anghelescu‐Dogaru Adina Graziella , Chitanu Gabrielle Charlotte , Tenhu Heikki
Published: June 2006

One of the present trends to increase the efficiency of the chrome tanning process is the use of chemicals which change the affinity and induce a better binding of the chromium ions in the hides. Recently, some anionic polyelectrolytes based on poly(acrylic acid) or maleic acid copolymers were developed as additives in the chrome tanning. The effect of polyelectrolytes could be explained by their interaction with the collagen from hide. In our work four maleic acid copolymer/collagen systems were investigated by turbidimetric, conductometric and potentiometric titrations. The interaction between the two macromolecular compounds was clearly evidenced, and its dependence on the chemical structure of the maleic acid copolymer and on the amount of added chromium ions was studied. Homogeneous systems or turbid dispersions were observed depending on the hydrophilic or hydrophobic character of the maleic copolymer, on the [CH]/[MP] ratio, and on the concentration of the chromium ions.
Structural Changes in Drawn Poly(L‐lactide)/Clay Hybrid Films
Authors: Ninomiya Naoya , Fujimori Atsuhiro , Masuko Toru
Published: June 2006

The films composed of poly(L‐lactide)(PLLA)/organoclay hybrids (PLACHs) have been prepared via a melt‐compounding process, in which the organoclay paticles are uniformly dispersed in the PLLA matrix. The changes in PLLA crystal orientation for the uniaxially drawn films were studied by differential scanning calorimetry, X‐ray diffractometry and transmission electron microscopy. Additionally, temperature dependence of the mechanical properties for these drawn films were examined by a dynamic viscoelastometer. After drawing the quenched PLACHs film at 90 °C, the orientation and crystallinity of PLLA crystal increased rapidly with increasing drawing ratio (λ) in the range more than 3 times. At the higher λ, the organoclay platelet particles in the PLACHs became parallel to the draw direction. The mechanical properties of drawn PLACHs were strongly dependent on both clay concentration and λ.
Entries in the Leiden Duchenne muscular dystrophy mutation database: An overview of mutation types and paradoxical cases that confirm the reading‐frame rule
Authors: Aartsma‐Rus Annemieke , Van Deutekom Judith C. T. , Fokkema Ivo F. , Van Ommen Gert‐Jan B. , Den Dunnen Johan T.
Published: June 2006

The severe Duchenne and milder Becker muscular dystrophy are both caused by mutations in the DMD gene. This gene codes for dystrophin, a protein important for maintaining the stability of muscle‐fiber membranes. In 1988, Monaco and colleagues postulated an explanation for the phenotypic difference between Duchenne and Becker patients in the reading‐frame rule: In Duchenne patients, mutations induce a shift in the reading frame leading to prematurely truncated, dysfunctional dystrophins. In Becker patients, in‐frame mutations allow the synthesis of internally deleted, but largely functional dystrophins. Currently, over 4700 mutations have been reported in the Leiden DMD mutation database, of which 91% are in agreement with this rule. In this study we provide an update of the mutational variability in the DMD gene, particularly focusing on genotype–phenotype correlations and mutations that appear to be exceptions to the reading‐frame rule. Muscle Nerve, 2006
Stretch‐induced force deficits in murine extensor digitorum longus muscles after cardiotoxin injection
Authors: Markert Chad , Petroski Gregory F. , Childers Charles K. , McDonald Kerry S. , Childers Martin K.
Published: June 2006

A leftward shift in a muscle's length–tension relationship is thought to impair myofilament overlap. We hypothesized that left‐shifted muscles would incur greater eccentric contraction–induced damage compared to controls. We evaluated contractile properties and force deficits in regenerating murine extensor digitorum longus (EDL) muscles 7, 14, and 21 days after cardiotoxin (CTX) injection. Specific tension recovered to control values by 21 days. CTX‐injected muscles demonstrated left‐shifted length–tension curves and incurred greater contraction‐induced force deficits than controls (P < 0.001) on day 7. We speculate that increased contraction‐induced damage in 7‐day CTX‐injected muscles results from changes in myofilament overlap that occurs during early regeneration. Muscle Nerve, 2006
CAV3 gene mutation analysis in patients with idiopathic hyper‐CK‐emia
Authors: Reijneveld Jaap C. , Ginjaar Ieke B. , Frankhuizen Wendy S. , Notermans Nicolette C.
Published: June 2006

As caveolin‐3 deficiencies may explain persistent hyper‐CK‐emia, we performed CAV3 gene mutation analysis and immunohistochemistry for caveolin‐3 in 31 patients with idiopathic hyper‐CK‐emia. In 2 of 29 patients who donated blood, variants in the CAV3 gene were detected. Although immunohistochemical analysis strongly suggested that caveolin‐3 was properly localized in the muscle tissue of the two affected patients, it may not function normally and could thus explain their persistent hyper‐CK‐emia. Our findings contribute to the clarification of unexplained persistent hyper‐CK‐emia, but further research is needed before CAV3 gene mutation analysis becomes part of the routine evaluation of these patients. Muscle Nerve, 2006
Structural properties of network revenue management models: An economic perspective
Authors: Morton Alec
Published: June 2006

Many revenue management problems have a network aspect. In this paper, we argue that a network can be thought of as a system of substitutable and complementary products, and the value of a revenue management model should be supermodular or submodular in the availability of two resources as the resources are economic substitutes or complements. We demonstrate that this is true in the case of a two‐resource dynamic stochastic revenue management model and show how this applies for multi‐resource deterministic static revenue management models. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Autonomic self‐organization architecture for wireless sensor communications
Authors: Chen Jiann‐Liang , Lu Hsi‐Feng , Lee Chien‐An
Published: June 2006

Wireless sensor nodes may be spread over large areas and long distances, and require multi‐hop communications between nodes, making direct management numerous wireless sensor nodes inefficient. Hierarchical management can be adopted to control several nodes. Effectively controlling the top‐level nodes can decrease the costs of managing nodes and of the communication among them. The lower‐level nodes are controlled and organized with the higher‐level nodes. This study presents an algorithm for self‐organization mechanism of higher‐level nodes, contesting member nodes by multi‐hop to form hierarchical clusters, and applying the ‘20/80 rule’ to determine the ratio of headers to member nodes. Furthermore, the broadcast tree is constructed with the minimum number of hops. Simulation results indicate that the mechanism has a 6–22% lower cover loss than other approaches. The average delay of the minimum hop count approach is 0.22–1.57ms less than that of free hop count approach. The simulation also reveals the influence of 20/80 rule on cluster formation between sensor nodes. Copyright © 2006 John Wiley & Sons, Ltd.
Safety of medications prescribed before and during early pregnancy in a cohort of 81 975 mothers from the UK General Practice Research Database
Authors: Hardy Janet R. , Leaderer Brian P. , Holford Theodore R. , Hall Gillian C. , Bracken Michael B.
Published: June 2006

Purpose

To demonstrate a linkage methodology for mother and baby automated medical records, and describe frequency, type, and pregnancy risk level of medications prescribed during pregnancy in a GPRD cohort, 1991–1999.

Methods

We linked records using a two‐stage algorithm and selected pairs with ≥7 months prenatal records and ≥2 records in baby's first year of life. Periods of interest were: 90 days prior to a woman's earliest identified pregnancy record (Period I), and this record plus 70 days (Period II, approximate early pregnancy). Medications were classified using the British National Formulary and US Food and Drug Administration Pregnancy Risk Categories.

Results

We achieved over 80% record linkage and defined a cohort of 81 975. Sixty‐five per cent of mothers had ≥1 prescription during both periods combined. Most frequent medications in Period I were anti‐bacterial, contraceptive, topical steroid, and bronchodilator. In Period II, they were folic acid, anti‐bacterial, antacid, and gynecological anti‐infective. In Period I, 4% were FDA category A (considered safest), 34% B, and 49% C and D combined. By Period II, prescription of category A medications increased (folic acid, iron) while other categories declined. Category X medications, with potential teratogenic risk that outweighs maternal benefit, were prescribed to 5714 (7%) women in Period I, and 501 (0.6%) women in Period II (46% progesterone).

Conclusions

One in every 164 women received a category X prescription in early pregnancy. The visit when pregnancy is first medically recognized represents an opportunity to review prescribed medications in light of contraindication and/or fetal risk. Copyright © 2006 John Wiley & Sons, Ltd.
Proteomic characterization of human serum proteins associated with the fat‐derived hormone adiponectin
Authors: Wang Yu , Xu Lance Yi , Lam Karen S. L. , Lu Gang , Cooper Garth J. S. , Xu Aimin
Published: June 2006

Adiponectin is a fat cell‐secreted hormone with antidiabetic and anti‐inflammatory activities. The reduced adiponectin levels are associated with obesity‐related metabolic syndrome. Replenishment of this hormone into animal models can improve insulin sensitivity, decrease blood glucose and lipid levels, and prevent the development of atherosclerosis and fatty liver injury. Despite these findings, the underlying molecular mechanisms remain largely unknown. Here, we have used affinity chromatography to purify the protein complexes that are associated with adiponectin in human serum. The nature of these adiponectin‐binding proteins was analyzed by MS/MS. Eight proteins from the adiponectin‐containing protein mixtures have been identified. Many of them, including thrombospondin‐1 (TSP‐1), histidine‐rich glycoprotein, kininogen 1, and alpha 2 macroglobulin (alpha2M), are well‐known glycoproteins involved in the regulation of inflammation, angiogenesis, and tissue remodeling. Coimmunoprecipitation and radioligand competitive‐binding assays confirmed the direct interactions between adiponectin and alpha2M, or TSP‐1. Moreover, these specific bindings were also detected in the serum samples derived from both healthy human subjects and patients with type 2 diabetes. In summary, our study demonstrated that, in the circulation, adiponectin forms protein complexes with other serum proteins. These proteins might serve as the physiological‐binding partners of adiponectin and regulate its bioavailability and biological activities.