bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic morphine induces premature mitosis of proliferating cells in the adult mouse subgranular zone
Authors: Mandyam Chitra D. , Norris Rebekah D. , Eisch Amelia J.
Published: May 2004

The birth of cells with neurogenic potential in the adult brain is assessed commonly by detection of exogenous S phase markers, such as bromodeoxyuridine (BrdU). Analysis of other phases of the cell cycle, however, can provide insight into how external factors, such as opiates, influence the cycling of newly born cells. To this end, we examined the expression of two endogenous cell cycle markers in relation to BrdU: proliferating cell nuclear antigen (PCNA) and phosphorylated histone H3 (pHisH3). Two hours after one intraperitoneal BrdU injection, BrdU‐, PCNA‐, and pHisH3‐immunoreactive (IR) cells exhibited similar distribution in the adult mouse subgranular zone (SGZ). Quantitative analysis within the SGZ revealed a relative abundance of cells labeled for PCNA > BrdU >> pHisH3. Similar to our reports in rat SGZ, chronic morphine treatment decreased BrdU‐ and PCNA‐IR cells in mouse SGZ by 28 and 38%, respectively. We also show that pHisH3‐IR cells are influenced by chronic morphine to a greater extent (58% decrease) than are BrdU‐ or PCNA‐IR cells. Cell cycle phase analysis of SGZ BrdU‐IR cells using triple labeling for BrdU, PCNA, and pHisH3 revealed premature mitosis in chronic morphine‐treated mice. These results suggest that morphine‐treated mice have a shorter Gap2/mitosis (G2/M) phase when compared to sham‐treated mice. These findings demonstrate the power of using a combination of exogenous and endogenous cell cycle markers and nuclear morphology to track proliferating cells through different phases of the cell cycle and to reveal the regulation of cell cycle phase by chronic morphine. © 2004 Wiley‐Liss, Inc.
Immunohistochemical localization of phosphorylated protein kinase R and phosphorylated eukaryotic initiation factor‐2α in the central nervous system of SJL mice with experimental allergic encephalomyelitis
Authors: Chakrabarty Anuradha , Danley Marsha M. , LeVine Steven M.
Published: May 2004

Inflammatory cells enter the CNS and target myelin in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE), a model of MS, and inflammation is thought to induce stress responses in the CNS. Protein kinase R (PKR) and eukaryotic initiation factor‐2α (eIF2α) undergo phosphorylation in response to stress, and the phosphorylated forms of these proteins play a key role in regulating protein synthesis. The objective of this study was to investigate the expression profile of phospho‐PKR and phospho‐eIF2α during the course of EAE in order to advance the understanding of the stress response in this disease. In control animals (no encephalitogen with no emulsion; no encephalitogen with emulsion) and in preclinical EAE animals, phospho‐PKR immunoreactivity was present in oligodendrocytes and some neurons, whereas, in EAE animals with active disease there was widespread labeling of inflammatory cells, and these cells were present during the recovery period of EAE, albeit to a lesser extent. Double‐labeling studies revealed that T cells and a few macrophages were phospho‐PKR+. Phospho‐eIF2α immunoreactivity was detected in some oligodendrocytes in hindbrain sections of control animals. In EAE animals with active disease, the number of labeled oligodendrocytes increased, and inflammatory T cells also were labeled. Insofar as phospho‐PKR activates nuclear factor‐κB, it may facilitate cytokines expression by T cells. Alternatively, phospho‐PKR and phospho‐eIF2α may promote apoptosis as a way to regulate T‐cell number in the CNS. The expression of phospho‐eIF2α in oligodendrocytes during EAE likely is involved with inhibition of protein translation, which is a protective mechanism used to promote cell survival in response to inflammation. © 2004 Wiley‐Liss, Inc.
Synthesis of retinal ganglion cell phospholipids is under control of an endogenous circadian clock: Daily variations in phospholipid‐synthesizing enzyme activities
Authors: Garbarino‐Pico E. , Carpentieri A.R. , Castagnet P.I. , Pasquaré S.J. , Giusto N.M. , Caputto B.L. , Guido M.E.
Published: May 2004

Retinal ganglion cells (RGCs) are major components of the vertebrate circadian system. They send information to the brain, synchronizing the entire organism to the light‐dark cycles. We recently reported that chicken RGCs display daily variations in the biosynthesis of glycerophospholipids in constant darkness (DD). It was unclear whether this rhythmicity was driven by this population itself or by other retinal cells. Here we show that RGCs present circadian oscillations in the labeling of [32P]phospholipids both in vivo in constant light (LL) and in cultures of immunopurified embryonic cells. In vivo, there was greater [32P]orthophosphate incorporation into total phospholipids during the subjective day. Phosphatidylinositol (PI) was the most 32P‐labeled lipid at all times examined, displaying maximal levels during the subjective day and dusk. In addition, a significant daily variation was found in the activity of distinct enzymes of the pathway of phospholipid biosynthesis and degradation, such as lysophospholipid acyltransferases (AT II), phosphatidate phosphohydrolase (PAP), and diacylglycerol lipase (DGL) in cell preparations obtained in DD, exhibiting differential but coordinated temporal profiles. Furthermore, cultures of immunopurified RGCs synchronized by medium exchange displayed a circadian fluctuation in the phospholipid labeling. The results demonstrate that chicken RGCs contain circadian oscillators capable of generating metabolic oscillations in the biosynthesis of phospholipids autonomously. © 2004 Wiley‐Liss, Inc.
Synaptosomal glutamate and GABA transport in patients with temporal lobe epilepsy
Authors: Hoogland G. , Spierenburg H.A. , van Veelen C.W.M. , van Rijen P.C. , van Huffelen A.C. , de Graan P.N.E.
Published: May 2004

High‐affinity glutamate and GABA transporters found in the plasma membrane of neurons and glial cells terminate neurotransmission by rapidly removing extracellular transmitter. Impairment of transporter function has been implicated in the pathophysiologic mechanisms underlying epileptogenesis. We characterized glutamate and γ‐aminobutyric acid (GABA) transport in synaptosomes, isolated from neocortical and hippocampal biopsies of patients with temporal lobe epilepsy (TLE). We analyzed K+‐evoked release in the presence and absence of Ca2+ to determine vesicular and transporter‐mediated release, respectively. We also analyzed 3H‐glutamate and 3H‐GABA uptake, the effect of glutamate uptake inhibitors L‐trans‐pyrrolidine‐2,4‐dicarboxylic acid (tPDC) and DL‐threo‐β‐benzyloxyaspartate (TBOA), and GABA uptake inhibitor N‐(4,4‐diphenyl‐3‐butenyl)‐3‐piperidinecarboxylic acid (SK&F 89976‐A). Neocortical synaptosomes from TLE patients did not show vesicular glutamate release, strongly reduced transporter‐mediated release, and an increased basal release compared to that in rat synaptosomes. Furthermore, basal release was less sensitive to tPDC, and 3H‐glutamate uptake was reduced compared to that in rat synaptosomes. Vesicular GABA release from neocortical synaptosomes of TLE patients was reduced compared to that in rat synaptosomes, whereas transporter‐mediated release was hardly affected. Furthermore, basal GABA release was more than doubled, but neither basal nor stimulated release were increased by SK&F 89976‐A, which did significantly increase both types of GABA release in rat synaptosomes. Finally, 3H‐GABA uptake by synaptosomes from TLE patients was reduced significantly in hippocampus (0.19 ± 0.04%), compared to that in neocortex (0.32 ± 0.04%). Control experiments with human peritumoral cortical tissue suggest that impaired uptake of glutamate, but not of GABA, was caused in part by the hypoxic state of the biopsy. Our findings provide evidence for impaired function of glutamate and GABA transporters in human TLE. © 2004 Wiley‐Liss, Inc.
An experimental perspective on triggered gamma emission from nuclear isomers
Authors: Carroll J J
Published: May 2004

The study of triggered depopulation of nuclear isomers,
with accompanying gamma emission, is a rapidly-changing field that
is only now attaining some degree of maturity. Because isomer
decays via electromagnetic transitions are strongly inhibited, the
interaction of these levels with externally-produced photons
provides an important probe of nuclear structure. Also, since some
isomers may store large amounts of energy for long times, a number
of applications have been proposed, including the creation of a
gamma-ray laser. Early experiments conclusively demonstrated
triggering of the 1015-year isomer of 180Ta, but even a
partial correlation of the effect with known levels could only be
obtained recently. Investigations of triggering for the 31-year
isomer of 178Hf were initially guided just by systematics and
experiments are characterized by considerable controversy. Against
this background, the field of triggered gamma emission is entering
a new phase in which improved level data allow targeting of
specific potentially-useful transitions. This paper summarizes the
current state-of-the-art and discusses the changing nature of the
field.
Fully analytical simulation of Q-switched lasers
Authors: Hofer A , Graf Th , Lüthy W , Weber H P
Published: May 2004

The complete solution of the rate equations of a
Q-switched laser, a system of two nonlinear coupled differential
equations, is derived fully analytically with the aid of the
Lambert W-function. In contrast to numerical methods the
analytical solution allows to optimize the relevant laser
parameters very efficiently. As compared to numerical calculations
the analytical solutions lead to identical results and are
obtained much faster and in a very elegant way.
Modeling of step-like object images in scanning differential heterodyne microscope using rigorous diffraction theory
Authors: Akhmedzhanov I M , Baranov D V , Zolotov E M
Published: May 2004

A theory of the image formation for a scanning differential heterodyne microscope is presented using the rigorous diffraction theory for perfectly conducting arbitrary-surfaced object. Computed results are compared with experimental responses to a step-like object with the 0.35 μm height and the 0.3 μm transition. The superresolving object characterization is analyzed using a variation of step parameters. An enhancement of microscope sensitivity using an adjustment of the interval between probing spots and choosing the polarization state of probing beams is investigated. The responses obtained with the rigorous method and those obtained by means of the scalar diffraction theory are compared.
Birefringence-controlled anti-Stokes line emission from a microstructure
fiber
Authors: Hu Ming Lie , Wang Ching-yue , Chai Lu , Li Yanfeng , Dukel'skii K V , Khokhlov A V , Shevandin V S , Kondrat'ev Yu N , Zheltikov A M
Published: May 2004

Microstructure fibers with a specially designed form
birefringence are shown to be ideally suited for the creation of
highly efficient frequency-tunable sources of short pulses in the
visible range. We use unamplified 35-fs pulses of 820-nm Ti:
sapphire laser radiation to demonstrate efficient generation of an
intense anti-Stokes signal in an elliptical-core fused silica
microstructure fiber. The central wavelength of this anti-Stokes
signal can be switched between 490 and 510 nm by coupling the pump
pulses into the fast and slow modes of the microstructure fiber.
Near-field imaging of light diffraction out of slab waveguides
Authors: Volkov V S , Bozhevolnyi S I , Taillaert D
Published: May 2004

A collection scanning near-field optical microscope
(SNOM) is used to image the propagating of light at
telecommunication wavelengths (1520-1570 nm) along photonic
crystal (PhC) slabs, which combine slab waveguides with in-plane
PhCs consisting of one- and two-dimensional gratings. The
efficient out-of-plane light diffraction is directly observed for
both 1D and 2D gratings (period 590 nm) fabricated on
silicon-on-insulator wafers and the corresponding SNOM images are
presented. Using the obtained SNOM images, we analyze light
intensity distributions along diffraction gratings measured at
different wavelengths and/or distances from the sample surface.
Production of exotic nuclear isomers in multi-nucleon transfer reactions
Authors: Regan P H , Valiente-Dobón J J , Wheldon C , Wu C Y , Smith J F , Macchiavelli A O , Cline D , Chakrawarthy R S , Chapman R , Cromaz M , Fallon P , Freeman S J , Görgen A , Gelletly W , Hayes A , Langdown S D , Lee I Y , Liang X , Pearson C J , Podolyák Zs , Teng R , Ward D , Warner D D , Yamamoto A D
Published: May 2004

This paper reports on recent work using multi-nucleon transfer reactions to populate metastable states in neutron-rich, rare-earth and transitional nuclei with A∼180-200. The use of a position sensitive gas-filled detector, CHICO, allowed the directions of the binary fragments to be measured, thereby enabling event-by-event Doppler corrections to be made for the prompt, in-beam transitions depopulating the nuclei of interest. By using the temporal calibration provided by (i) the measurement of the binary reaction fragments and (ii) the natural pulsing of the cyclotron beam, transitions from metastable states with lifetimes in the nano-to-microsecond regime could be identified. The complementarity of this technique with the novel use of relativistic projectile fragmentation reactions is outlined, together with potential future avenues for this research, with a particular emphasis on the population of exotic isomeric states at high angular momentum and excitation energy values.
Peroxidase‐Catalyzed Oxidative Polymerization of Phenol with a Nonionic Polymer Surfactant Template in Water
Authors: Kim Young‐Jin , Uyama Hiroshi , Kobayashi Shiro
Published: May 2004

Summary: Peroxidase‐catalyzed oxidative polymerization of phenol has been examined using the template, poly(ethylene glycol) monododecyl ether (PEGMDE), in water. The role of this template, which forms a complex with phenol in the polymerization, was verified by UV measurements. During the reaction, a complex of the resulting polymer and PEGMDE was precipitated in high yields. The amount and the PEG chain length of PEGMDE strongly affected the polyphenol yield. The unit molar ratio of polyphenol and PEG of the template was about 1:0.9. The presence of the PEGMDE template in the aqueous medium greatly improved the regioselectivity of the polymerization, yielding polyphenol with a phenylene unit content close to 90%. FT‐IR, DSC, and XRD analyses confirmed the formation of the miscible complex of polyphenol and PEGMDE by hydrogen‐bonding interactions.

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Polyelectrolyte Complex Films Derived from Polyethyleneoxide‐Maleic Acid Copolymer and Chitosan: Preparation and Characterization
Authors: Shin‐Ya Yoshitsune , Tsurushima Hideo , Tsurumi Taro , Kajiuchi Toshio , Leong Kam W.
Published: May 2004

Summary: Polyelectrolyte complex films were prepared with polyethyleneoxide‐maleic acid copolymer and chitosan using a casting/solvent evaporation method. The films were examined in terms of their IR spectra, surface and cross‐section morphologies, cytotoxicity, and swelling behavior at different pH levels. To assess the potential of these films as a biomedical device, the profiles of the release of model drug from the CS/PEOMA films were examined at pH 4.8. The surface morphology of the films was quite smooth and uniform, and the cross‐sectional morphology was dense and homogeneous. The swelling behaviors of CS/PEOMA films were found to depend on the pH of the solution as well as on the CS/PEOMA composition. Drug release from different CS/PEOMA films at pH 4.8 was found to be dependent on film composition. The results showed the potential applicability of CS/PEOMA film as a drug delivery vehicle.

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Na+ and Mg2+ Ion Effect on the Stability of a Poly I · Poly A · Poly I Triple Helix
Authors: Sorokin Victor A. , Valeev Vladimir A. , Andrus Elena A. , Gladchenko Galina O. , Blagoi Yuri P.
Published: May 2004

Summary: Differential UV spectroscopy was used to study the temperature dependence of the conformational equilibrium in aqueous poly I · poly A · poly I (A2I) solutions containing Na+ (0.1–2 M) and Mg2+ (10−5–0.005 M) ions. Over the whole range of the studied Na+ and Mg2+ concentrations, the heating‐induced destruction of the triple A2I helix is actually the A2I → A + I + I (3 → 1) transition. The rise of the transition temperature with increasing Na+ and Mg2+ contents is well described by Manning's and the “ligand” theories, which makes it possible to estimate the linear charge density on the single‐stranded poly I (ξ = 1.9 ± 0.1) and the Mg2+–A2I binding constant (K = 1 250 M−1 for the zero degree of binding). An analytical expression has been obtained, which correlates the constants of Mg2+ binding to three‐ and single‐stranded polynucleotides (K3 and K1, respectively) and the linear charge density on them. There are only minor distinctions between the K3 values for A2U and A2I because these polynucleotides have similar structures. The difference in the K1 values is also slight as single‐stranded poly U, poly I, and poly A have similar conformations.

Dependence of the conformational transition temperatures of two triple helices with changing Mg2+ concentration.

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Dependence of the conformational transition temperatures of two triple helices with changing Mg2+ concentration.
Synthesis and Characterization of Epoxidized Styrene‐Butadiene Block Copolymers as Templates for Nanostructured Thermosets
Authors: Serrano Elena , Larrañaga Maider , Remiro Pedro M. , Mondragon Iñaki , Carrasco Pedro M. , Pomposo Jose A. , Mecerreyes David
Published: May 2004

Summary: A wide range of epoxidized styrene‐block‐butadiene block copolymers were synthesized using hydrogen peroxide in the presence of an in situ prepared methyltrioctylammoniumtetrakis(diperoxotungstate)phosphate as the catalyst system in a water/dichloroethane biphasic system. 1H NMR and FT‐IR spectra revealed that the epoxidation procedure led mainly to 1,4‐epoxidized butadiene units. GPC analysis showed that epoxidation changed the copolymer architecture into stars with fewer arms. The copolymers showed two glass transition temperatures in accordance with the phase separation for block copolymers and, as revealed in AFM images, the self‐assembly takes place on a nanometer scale. Moreover, epoxidized styrene‐butadiene (SB) copolymers showed improved miscibility with epoxy monomers leading to self‐assembled nanostructures in the uncured state. This allows them to be used as templates for nanostructured resins.

TM‐AFM phase images for: a) 40 mol‐% epoxidized copolymer (scale bar = 300 nm); b) uncured blend containing 50 wt.‐% DGEBA in 50 mol‐% epoxidized copolymer (scale bar = 1 μm), after annealing at 80 °C in vacuum for 3 h.

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TM‐AFM phase images for: a) 40 mol‐% epoxidized copolymer (scale bar = 300 nm); b) uncured blend containing 50 wt.‐% DGEBA in 50 mol‐% epoxidized copolymer (scale bar = 1 μm), after annealing at 80 °C in vacuum for 3 h.
Immiscible Poly(L‐lactide)/Poly(ε‐caprolactone) Blends: Influence of the Addition of a Poly(L‐lactide)‐Poly(oxyethylene) Block Copolymer on Thermal Behavior and Morphology
Authors: Maglio Giovanni , Malinconico Mario , Migliozzi Anna , Groeninckx Gabriel
Published: May 2004

Summary: A binary blend of poly (L‐lactide) (PLLA) and poly(ε‐caprolactone) (PCL) of composition 70:30 by weight was prepared using a twin screw miniextruder and investigated by differential scanning calorimetry (DSC), optical microscopy and scanning electron microscopy (SEM). Ternary 70:30:2 blends were also obtained by adding either a diblock copolymer of PLLA and poly(oxyethylene) (PEO) or a triblock PLLA‐PCL‐PLLA copolymer as a third component. Optical microscopy revealed that the domain size of dispersed PCL domains is reduced by one order of magnitude in the presence of both copolymers. SEM confirmed the strong reduction in particle size upon the addition of the copolymers, with an indication of an enhanced emulsifying effect in the case of the PLLA‐PEO copolymer. These results are analyzed on the basis of solubility parameters of the blend components.

Optical micrograph of M3EG2 blend melt quenched at 125 °C.

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Optical micrograph of M3EG2 blend melt quenched at 125 °C.
Synthesis of Poly(ester‐anhydrides) Based on Different Polyester Precursors
Authors: Korhonen Harri , Helminen Antti O. , Seppälä Jukka V.
Published: May 2004

Summary: Poly(ester‐anhydrides) were synthesised from poly(L‐lactide), poly(D,L‐lactide), and poly(ε‐caprolactone) prepolymers prepared by ring‐opening polymerisation of cyclic esters in the presence of 1,4‐butanediol or ricinoleic acid as co‐initiator. The hydroxyl group end functionality of the prepolymers was converted to carboxylic acid functionality by reaction with succinic anhydride, and the polyester precursors were coupled by melt polycondensation to give poly(ester‐anhydrides). 1,4‐Butanediol was used as co‐initiator to study the properties of poly(ester‐anhydrides) prepared from different monomers, whereas ricinoleic acid was used as co‐initiator to introduce a hydrophobic fatty acid moiety to the polyester precursor. In hydrolysis tests, the poly(ester‐anhydrides) showed a two‐stage degradation comprising a rapid hydrolysis of anhydride linkages within three days, followed by the slower hydrolysis of the remaining polyester oligomer. Weight loss of the poly(ester‐anhydrides) depended most importantly on molecular weight and thermal properties of the polyester precursors; thus, poly(ester‐anhydrides) prepared from low molecular weight prepolymers having thermal transitions below 37 °C showed very fast weight loss.

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Mechanical Behavior and Fracture Toughness of Poly(L‐lactic acid)‐Natural Fiber Composites Modified with Hyperbranched Polymers
Authors: Wong Susan , Shanks Robert A. , Hodzic Alma
Published: May 2004

Summary: The use of hyperbranched polymers (HBP) with hydroxy functionality as modifiers for poly(L‐lactic acid) (PLLA)‐flax fiber composites is presented. HBP concentrations were varied from 0 to 50% v/v and the static and dynamic tensile properties were investigated along with interlaminar fracture toughness. Upon addition of HBP, the tensile modulus and dynamic storage modulus (E′) both diminished, although a greater decline was noticed in the static modulus. The elongation of the composites with HBP showed a pronounced increase as large as 314% at 50% v/v HBP. The loss factor (tan δ) indicated a lowering of the glass transition temperature (Tg) due to a change in crystal morphology from large, mixed perfection spherulites to finer, smaller spherulites. The change in Tg could have also resulted from some of the HBP being miscible in the amorphous phase, which caused a plasticizing effect of the PLLA. The interlaminar fracture toughness measured as the critical strain energy release rate (GIC) was significantly influenced by HBP. At 10% v/v HBP, GIC was at least double that of the unmodified composite and a rise as great as 250% was achieved with 50% v/v. The main factor contributing to high fracture toughness in this study was better wetting of the fibers by the matrix when the HBP was present. With improved ductility of the matrix, it caused ductile tearing along the fiber‐matrix interface during crack propagation.

ESEM photograph of propagation region of the interlaminar fracture toughness specimens with 30% v/v of HBP.

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ESEM photograph of propagation region of the interlaminar fracture toughness specimens with 30% v/v of HBP.
Phenolic Hyperbranched Polymers as Additives in Cationic Photopolymerization of Epoxy Systems
Authors: Sangermano Marco , Priola Aldo , Malucelli Giulio , Bongiovanni Roberta , Quaglia Andrea , Voit Brigitte , Ziemer Antje
Published: May 2004

Summary: A phenolic group containing hyperbranched polyester (HBP) was synthesized and employed as chain transfer agent in cationic photopolymerization of a biscycloaliphatic epoxy monomer (CE). The epoxy group conversion increases by increasing the amount of HBP in the photocurable resin, due to a chain transfer reaction involving the phenolic‐OH groups. HBP acts as a plasticizer inducing decrease of the Tg values together with an increase of the toughness properties. Meanwhile gel content increases together with the E′ values. By increasing the amount of HBP in the photocurable resin an increase of the density is evident indicating a decrease of free volume. Therefore an improvement of the gas barrier properties might be expected; at the same time an increase of the thermal stability is evident.

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Physical and Mechanical Interfacial Properties of Epoxy Copolymers Initiated by Latent Thermal Catalysts
Authors: Park Soo‐Jin , Kang Jun‐Gil , Kwon Soo‐Han
Published: May 2004

Summary: The epoxy copolymers containing sulfone groups, diglycidyl ether of bisphenol‐A – Bisphenol‐S (DGEBA‐S) were synthesized by a hot‐melt method. The thermal properties of the epoxy systems initiated by two cationic latent catalysts, i.e., N‐benzylpyrazinium hexafluoroantimonate (BPH) and N‐benzylquinoxalinium hexafluoroantimonate (BQH), were investigated by using a dynamic DSC, DMA, and TGA. The mechanical properties were measured by single‐edge‐notched (SEN) beam fracture toughness tests. As a result, the thermal stability and mechanical interfacial properties of the DGEBA‐S/catalyst system were found to be higher than those of the DGEBA/catalyst. This was probably due to the fact that the introduction of sulfone groups with a polar nature to the main chain of the epoxy resins led to an improvement of thermal stability and toughness of the cured epoxy copolymers.

Conversion of the epoxy/catalyst systems as a function of curing temperature.

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Conversion of the epoxy/catalyst systems as a function of curing temperature.
Large Scale Fractionation of Macromolecules
Authors: Eckelt John , Haase Tanja , Loske Stefan , Wolf Bernhard A.
Published: May 2004

Summary: Access to sufficiently large amounts of material with adequate molecular and chemical uniformity from polydisperse natural products or synthetic materials has been a long‐standing challenge to polymer scientists. We have developed a broadly applicable preparative fractionation method consisting of a special kind of continuous extraction removing the easier soluble components from the initial product. It is rendered possible by the use of spinning nozzles through which a concentrated polymer solution is pressed into a liquid of tailored thermodynamic quality. The initially produced jets of the source phase disintegrate rapidly into minute droplets of typically 50 μm diameter. This efficient subdivision provides the large surfaces and short routs of transport required for successful fractionation. Thus the pronounced kinetic hindrances resulting from the high viscosities of reasonable concentrated polymer solutions can be overcome. We portray the principal features of continuous spin fractionation and present two examples of practical importance.

Functional principle of ‘continuous spin fractionation’ (CSF).

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Functional principle of ‘continuous spin fractionation’ (CSF).
The Estimation of the Molecular Weight of Polytetrafluoroethylene Based on the Heat of Crystallisation. A Comment on Suwa's Equation
Authors: Lappan Uwe , Geißler Uwe , Häußler Liane , Pompe Gisela , Scheler Ulrich
Published: May 2004

Summary: The influence of number‐average molecular weight $\overline M _{\rm n}$ ranging from 1.4 · 104 to 1.2 · 106 g/mol on the thermal behaviour of polytetrafluoroethylene (PTFE) has been studied. Samples have been prepared by radiation‐induced degradation of commercial PTFE. The molecular weight $\overline M _{\rm n}$ has been calculated using end‐group concentration determined by infrared (IR) spectroscopy and 19F solid‐state nuclear magnetic resonance (NMR) spectroscopy. Melting and crystallisation heats were investigated by differential scanning calorimetry (DSC). The results have been discussed with respect to quantitative relationships between number‐average molecular weight and heat of crystallisation of PTFE described in the literature. The molecular weight calculated from Suwa's equation, which is often used in the literature, has been found to be too low.

Concentration of end‐groups and the molecular weight of PTFE versus the irradiation dose.

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Concentration of end‐groups and the molecular weight of PTFE versus the irradiation dose.
A New Approach to the Evaluation of Stabilizer Efficiency Under Photo‐Ageing
Authors: Kumar Ashustosh , Commereuc Sophie , Verney Vincent , Lajoie Pierre , Lacoste Jacques
Published: May 2004

Summary: Elastomers are very sensitive to oxidative degradation due to the combined effect of light and oxygen. Hence, we investigate the impact of stabilizers on the evolution of molecular structure of elastomers through photo‐oxidation. While a dual processes is generally reported to describe photo‐oxidation of elastomers (oxidation by‐products formation and crosslinking), the aim of the current study is to provide a complete characterization of the efficiency of additives taking into account the dual processes: chemical changes (formation of photoproducts) and molecular structure changes (crosslinking). This work gives new insights about relationships between chemical changes and physical properties evolution of the material through ageing. We conclude that the two phenomenon are correlated to the primary peroxidation reaction and a dual efficiency does not exist for any additive.

Kinetic curves of carbonylated by‐products formation upon photooxidation of stabilized EPDM films comparing with a unstabilized reference.

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Kinetic curves of carbonylated by‐products formation upon photooxidation of stabilized EPDM films comparing with a unstabilized reference.
Essential Work of Fracture Parameters of in‐situ Microfibrillar Poly(ethylene terephthalate)/Polyethylene Blend: Influences of Blend Composition
Authors: Li Zhong‐Ming , Yang Wei , Huang Rui , Fang Xiang‐Ping , Yang Ming‐Bo
Published: May 2004

Summary: An in‐situ microfibrillar blend based on poly(ethylene terephthalate) (PET) and polyethylene (PE) was fabricated through slit die extrusion, hot‐stretching and quenching. The morphology of the PET in‐situ microfibers, which were observed after the matrix was etched away, appears to be dependent on the blend composition at a fixed hot stretch ratio. The well‐defined in‐situ fibers were generated at the PET concentrations ranging from 15 to 25 wt.‐%. The fracture toughness of the microfibrillar blend was evaluated using deeply double‐edge notched tension (DDENT) specimens according to the essential work of fracture procedure. Initially, the increase of PET concentration makes we rise. At 15 wt.‐% of PET concentration there exists a maximum we. Further increase of PET microfibers causes a rapid decrease of we. On the other hand, incorporation of PET microfibers at a low concentration to PE makes wp rise slightly. As it exceeds 10 wt.‐%, wp decreases substantially. It was believed that the characteristics of the PET microfibers were responsible for the fracture behaviors of the microfibrillar blend.

Morphology of PET microfibers in the PET/PE microfibrillar blend in which the matrix PE was etched away by hot xylene.

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Morphology of PET microfibers in the PET/PE microfibrillar blend in which the matrix PE was etched away by hot xylene.
On the Navier‐Stokes equation with boundary conditions based on vorticity
Authors: Bellout Hamid , Neustupa Jiří , Penel Patrick
Published: May 2004

We treat the Stokes and the Navier‐Stokes equation with the conditions curlku · n = 0 (k = 0, 1, 2) on the boundary of the flow field. The approach is based on a spectral analysis and properties of operator curl. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exterior stationary Navier‐Stokes flows in 3D with non‐zero velocity at infinity: approximation by flows in bounded domains
Authors: Deuring Paul , Kračmar Stanislav
Published: May 2004

We consider stationary incompressible Navier‐Stokes flows in an exterior domain ℝ3\$ \bar \Omega $, where Ω ⊂ ℝ3 is bounded and open. Under the assumption that the velocity at infinity is non‐zero, we present a variational problem in BR\$ \bar \Omega $ such that a solution of this variational problem approximates the given exterior flow. The error associated with this approximation is estimated in terms of R, among other quantities. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solutions of the Navier‐Stokes initial value problem in weighted Lq‐spaces
Authors: Fröhlich Andreas
Published: May 2004

The problem of strong solvability of the nonstationary Navier‐Stokes equations is considered in weighted Lq‐spaces Lqω(Ω), where the domain Ω ⊂ ℝn is the half space ℝn+ or a bounded domain with boundary of class C1,1 and the weight ω belongs to the Muckenhoupt class Aq. We give general conditions on the weight function ensuring the existence of a unique strong solution at least locally in time. In particular, these conditions admit weight functions ω ∈ Aq, which become singular at the boundary or, in the case Ω = ℝn+, grow for |x| →∞. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biorthogonal wavelet bases for the boundary element method
Authors: Harbrecht Helmut , Schneiderd Reinhold
Published: May 2004

As shown by Dahmen, Harbrecht and Schneider [7, 23, 32], the fully discrete wavelet Galerkin scheme for boundary integral equations scales linearly with the number of unknowns without compromising the accuracy of the underlying Galerkin scheme. The supposition is a wavelet basis with a sufficiently large number of vanishing moments. In this paper we present several constructions of appropriate wavelet bases on manifolds based on the biorthogonal spline wavelets of A. Cohen, I. Daubechies and J.‐C. Feauveau [4]. By numerical experiments we demonstrate that it is worthwhile to spent effort on their construction to increase the performance of the wavelet Galerkin scheme considerably. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a class of nonlinear cross‐correlation equations
Authors: v. Wolfersdorf Lothar , Wegert Elias
Published: May 2004

Nonlinear cross‐correlation equations in finite and semi‐infinite intervals are studied by means of Fourier transform and Cauchy integral techniques. The equations are reduced to a bilinear conjugacy problem for two analytic functions on the real axis which can be solved in explicit form.

In particular, Engibaryan's equations from nonlinear factorization theory of Wiener‐Hopf integral equations are treated in more complete manner than in the previous literature. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cover Picture: Macromol. Rapid Commun. 9/2004
Authors: Kohli Neeraj , Dvornic Petar R. , Kaganove Steven N. , Worden Robert M. , Lee Ilsoon
Published: May 2004

Cover: The picture shows multiple levels of structural order within micropatterned arrays of cross‐linkable, amphiphilic, dendrimer multilayers. The microcontact printing method allowed the film thickness of the nanostructured dendrimer arrays to be controlled.

Further details can be found in the Communication by N. Kohli, P. R. Dvornic, S. N. Kaganove, R. M. Worden, and I. Lee* on page 935.
Application of Fourier transform ion cyclotron resonance mass spectrometry to oligosaccharides
Authors: Park Youmie , Lebrilla Carlito B.
Published: May 2004

The application of Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) to the structural elucidation of oligosaccharides is described. This review covers the analyses of oligosaccharides in the context of the unique features of FTICR MS and the improvements in instrumentation that make it possible to study this class of compounds. It consists of work performed initially to understand the fundamental aspects of oligosaccharide ionization and unimolecular fragmentation. More recent investigation includes the application of the technique to samples of direct biological origin. Chemical and enzymatic degradation methods in conjunction with mass spectrometry (MS) and the use front‐end methods with FTICR MS are also discussed. The current applications including the characterization of bacterial lipooligosaccharides and phosporylated carbohydrates are described. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:232–264, 2005
Non‐subtype‐selective opioid receptor antagonism in treatment of levodopa‐induced motor complications in Parkinson's disease
Authors: Fox Susan , Silverdale Montague , Kellett Mark , Davies Rhys , Steiger Malcolm , Fletcher Nicholas , Crossman Alan , Brotchie Jonathan
Published: May 2004

Opioid peptide transmission is enhanced in the striatum of animal models and Parkinson's disease (PD) patients with levodopa‐induced motor complications. Opioid receptor antagonists reduce levodopa‐induced dyskinesia in primate models of PD; however, clinical trials to date have been inconclusive. A double‐blind, placebo controlled, crossover design study in 14 patients with PD experiencing motor fluctuations was carried out, using the non‐subtype‐selective opioid receptor antagonist naloxone. Naloxone did not reduce levodopa‐induced dyskinesia. The duration of action of levodopa was increased significantly by 17.5%. Non‐subtype‐selective opioid receptor antagonism may prove useful in the treatment of levodopa‐related wearing‐off in PD but not in dyskinesia. © 2003 Movement Disorder Society
Mitochondrial complex I and IV activities in leukocytes from patients with parkin mutations
Authors: Müftüoglu Meltem , Elibol Bülent , Dalmızrak Özlem , Ercan Ayse , Kulaksız Gülnihal , Ögüs Hamdi , Dalkara Turgay , Özer Nazmi
Published: May 2004

The parkin protein functions as a RING‐type ubiquitin protein ligase. Considering the possibility that impaired ubiquitin‐proteosomal system activity may impair antioxidant defenses and enhance oxidative stress, we have investigated the activity of mitochondrial respiratory enzymes in patients with parkin gene mutations. A significant decrease in the leukocyte complex I activity was found both in patients with parkin mutations (62.5%) and idiopathic PD (64.5%) compared with age‐matched controls (P < 0.001). Complex IV activity was also decreased significantly in idiopathic PD patients (60%), but no difference was detected between controls and patients with parkin mutations. © 2003 Movement Disorder Society
Computed tomographically‐controlled injection of botulinum toxin into the longus colli muscle in severe anterocollis
Authors: Herting Birgit , Wunderlich Silke , Glöckler Theresa , Bendszus Martin , Mucha Dirk , Reichmann Heinz , Naumann Markus
Published: May 2004

We report on a 44‐year‐old man who suffered from severe anterocollis. Repeated computed tomographically controlled injections of botulinum toxin into the right longus colli muscle allowed a precise location of the needle and injection of the toxin, leading to clear improvement of symptoms. © 2003 Movement Disorder Society
Unilateral deep brain stimulation of the internal globus pallidus alleviates tardive dyskinesia
Authors: Schrader Christoph , Peschel Thomas , Petermeyer Michael , Dengler Reinhard , Hellwig Dieter
Published: May 2004

We describe a patient with fluspirilene‐induced tardive dyskinesia of the choreiform oro‐facial‐laryngeal type resistant to various conservative approaches for 7 years who underwent deep brain stimulation of the internal pallidal globe. We found immediate and marked suppression of her perioral involuntary movements with unilateral stimulation at 60 Hz. © 2003 Movement Disorder Society
Verb and noun generation tasks in Huntington's disease
Authors: Péran Patrice , Démonet Jean‐François , Pernet Cyril , Cardebat Dominique
Published: May 2004

We compared noun‐ and verb‐generation tasks in a demented group (n = 9, Dementia Rating Scale ≤ 129) and in a non‐demented group (n = 17, Dementia Rating Scale > 129) of Huntington's disease (HD) patients compared to 26 matched normal subjects. We did not find a specific deficit for verb production in non‐demented patients who had a performance similar to but weaker than that of the controls across the four tasks. The profile of results was different in the demented group because, apart from a global deficit whatever the task in comparison with both non‐demented and control groups, the demented patients exhibited increased difficulties in the two tasks implying verb production. The deficit of verb production observed in demented HD patients is discussed in relation to the damage to the motor loop in HD patients at later stages of disease. © 2003 Movement Disorder Society
Grip force abnormalities in de novo Parkinson's disease
Authors: Fellows Stuart J. , Noth Johannes
Published: May 2004

In recent years it has been shown that a variety of movement disorders are associated with abnormalities of the fine motor control of the hand. In Parkinson's disease (PD), these changes consist of a slowing of the rate of grip force development and the use of abnormally large grip forces both during lifting and static holding of an object. It has been suggested, however, that these changes are a direct effect of the patient's levodopa medication or associated with levodopa induced dyskinesias. Accordingly, we examined the performance of de novo Parkinson patients in a precision lifting task. All patients (n = 6) were newly diagnosed and showed rigidity, bradykinesia, or both, but were unaffected by tremor or dyskinesia. None of the patients had received antiparkinson medication. Grip force was abnormally high in both the lifting and hold phases. This exaggeration was equal in magnitude to that observed previously in medicated patients. Thus we conclude that the abnormalities in grip force observed here are intrinsic features of PD and not the result of dopamine medication or its side effects. © 2004 Movement Disorder Society
Arg(184)his mutant GTP cyclohydrolase I, causing recessive hyperphenylalaninemia, is responsible for dopa‐responsive dystonia with parkinsonism: A case report
Authors: Kikuchi Akio , Takeda Atsushi , Fujihara Kazuo , Kimpara Teiko , Shiga Yusei , Tanji Hiroaki , Nagai Makiko , Ichinose Hiroshi , Urano Fumi , Okamura Nobuyuki , Arai Hiroyuki , Itoyama Yasuto
Published: May 2004

We describe a 54‐year‐old man with dominant adult‐onset dopa‐responsive dystonia (DRD) with parkinsonism caused by an Arg184His mutation in guanosine 5′‐triphosphate cyclohydrolase I (GCH‐I). This is the first mutation in the GCH‐I gene that has been proven to be responsible for both recessive and dominant phenotypes. © 2004 Movement Disorder Society
Cerebrospinal fluid analysis differentiates multiple system atrophy from Parkinson's disease
Authors: Abdo W. Farid , De Jong Daniëlle , Hendriks Jan C.M. , Horstink Martin W.I.M. , Kremer Berry P.H. , Bloem Bastiaan R. , Verbeek Marcel M.
Published: May 2004

We investigated whether cerebrospinal fluid (CSF) analysis discriminates between idiopathic Parkinson's disease (PD; n = 35) and multiple system atrophy (MSA; n = 30). The median CSF concentration of the neurotransmitter metabolites 5‐hydroxyindolacetic acid (5‐HIAA) and 3‐methoxy‐4‐hydroxyphenylethyleneglycol (MHPG) was reduced significantly (49‐70%) in MSA compared to PD. In contrast, several brain‐specific proteins (tau, neuron‐specific enolase, myelin basic protein) were elevated (130–230%) in MSA compared with those in PD. A combination of CSF tau and MHPG discriminated PD from MSA (adjusted odds ratios: tau, 27.2; MHPG, 0.14). Our data suggest that the more progressive and widespread neurodegenerative nature of MSA, as compared with PD, is reflected in the composition of CSF. We propose that CSF analysis may become part of the diagnostic work‐up of patients with parkinsonian syndromes. © 2003 Movement Disorder Society
Senile chorea treated by deep brain stimulation—A clinical, neurophysiological and functional imaging study
Authors: Yianni John , Nandi Dipankar , Bradley Kevin , Soper Nigel , Gregory Ralph , Joint Carole , Stein John , Scott Richard , Aziz Tipu
Published: May 2004

We report on a patient with senile chorea, treated with deep brain stimulation of the left globus pallidus internus and subsequently the left ventralis oralis posterior nucleus of the thalamus. Deep brain field potential recordings and functional imaging using single photon emission tomography enabled us to suggest pathophysiological mechanisms for the symptoms. © 2004 Movement Disorder Society
Propriospinal myoclonus after treatment with ciprofloxacin
Authors: Post Bart , Koelman Johannes H.T.M. , Tijssen Marina A.J.
Published: May 2004

The clinical and electrophysiological features of a truncal myoclonus in a 55‐year‐old man are described. The electromyographic characteristics point toward propriospinal myoclonus. It is suggested that a myoclonic generator was released after use of ciprofloxacin, by antagonising the γ‐aminobutyric acid metabolism. © 2004 Movement Disorder Society
Severe resting clonus caused by thyrotoxicosis in a 16‐year‐old girl with hereditary spastic paraparesis: A case report
Authors: Sanger Terence D.
Published: May 2004

A 16‐year‐old girl with a history of hereditary spastic paraparesis developed the subacute onset of severe clonus and new upper‐extremity spasticity due to thyrotoxicosis. This case demonstrates the ability of hyperthyroid states to worsen symptoms of spasticity in a child with an underlying spastic disorder. It also demonstrates the importance of investigating for common systemic diseases as a cause of movement disorders even in children with underlying known genetic disorders. © 2004 Movement Disorder Society
Status dissociatus after surgery for tegmental ponto‐mesencephalic cavernoma: A state‐dependent disorder of motor control during sleep
Authors: Provini Federica , Vetrugno Roberto , Pastorelli Francesca , Lombardi Carolina , Plazzi Giuseppe , Marliani Anna Federica , Lugaresi Elio , Montagna Pasquale
Published: May 2004

After surgery for a tegmental ponto‐mesencephalic cavernoma, a patient developed sleep‐related excessive fragmentary myoclonus, diffuse myoclonic jerks, simple quasipurposeful movements of the limbs, and rapid eye movement (REM) sleep behaviour disorder as motor features of status dissociatus, a condition in which elements of one state of being (wake, NREM and REM sleep) pathologically intrude into another. © 2004 Movement Disorder Society
Deep brain stimulation in myoclonus–dystonia syndrome
Authors: Cif Laura , Valente Enza Maria , Hemm Simone , Coubes Christine , Vayssiere Nathalie , Serrat Stéphanie , Di Giorgio Annalisa , Coubes Philippe
Published: May 2004

Myoclonus–dystonia syndrome (MDS) is an autosomal dominant disorder characterized by bilateral myoclonic jerks. An 8‐year‐old boy presenting with early onset, medically intractable, MDS due to a mutation in the ϵ‐sarcoglycan gene (SGCE) underwent chronic bilateral stimulation of the globus pallidus internus, which eliminates both myoclonus and dystonia. We conclude that deep brain stimulation can be an effective and safe treatment for MDS. © 2004 Movement Disorder Society