bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron transfer at the solid liquid interface; new insights on the mechanism of formation of the grignard reagent
Authors: Chanon Michel , Négrel Jean Claude , Bodineau Nicolas , Mattalia Jean Marc , Péralez Eric , Goursot Annick
Published: March 2011

The strong inhibiting effect of trace quantities of selected compounds on the reaction between ultra fine particles of magnesium and alkyl halides in THF strongly suggests that the generally accepted linear mechanism should be replaced by a chain mechanism. The reactivity of batteries of free radical clocks centered on an aliphatic skeleton displays unexpected leaving group effects. Such effects could be rationalized according to a variety of mechanistic schemes. The main ones are: 1) coexistence of polar and electron transfer routes, 2) participation of solvated electrons in the mechanism, 3) gradient of reactivity starting from the magnesium surface to the bulk solution. A series of experiments aiming at a choice between these possibilities is described.
Recycling of cheap packaging waste versus expensive engineering materials
Authors: Karlsson Sigbritt , Albertsson Ann‐Christine
Published: March 2011

The economical incitement is larger for recycling of expensive engineering materials than for packaging plastics. It should, however, be possible also for municipal waste industry to profit from recycling of packaging waste. At present, municipal waste plants already sell sorted plastics fractions on the order basis. The degree of mixing of these plastic fractions is the key question to be solved in order to obtain a high‐quality product. The value of recycled HDPE fraction is lowered if it contains impurities of other polymers, e.g. PP, PS or PET because such impurities cause embrittlement. An addition of an impact modifier to contaminated HDPE was analyzed with respect to changes in morphology and mechanical properties. Oxidative stability of the polymer matrix decreased as a result of recycling, indicating decomposition of heat stabilizers, as shown for polyamide 66. The relation between expensive/cheap recycled plastics is discussed based on their long‐term properties.
The origin and role of structural inhomogeneities and impurities in material recycling of plastics
Authors: Pospíšil Jan , Horák Zdenêk , Kruliš Zdenêk , Nešpůrek Stanislav
Published: March 2011

Characteristics of aged polymers intended for material recycling are emphasized. Specific material properties of aged recyclates, containing new functional groups formed during processing and first‐life application (structural polymer inhomogeneities) and metallic compounds, pigments or compounds generated from additives (non‐polymeric impurities), are considered from the point of view of their influence on the aging resistance in the second‐life applications. Chemical transformations of the polymer matrix together with consumption of stabilizers deteriorate material properties of collected waste plastics in reprocessing and subsequent outdoor applications.
Polymer recycling: Thermodynamics and economics
Authors: Stein Richard S.
Published: March 2011

Polymer recycling must conform to thermodynamic laws and economic restrictions. The objective of polymer recycling is twofold: (1) the reduction of rubbish and the burden of waste polymers on the environment, and (2) the conservation of resources. The environmental burden should be considered as part of the cost for employing polymers. Polymer input to landfills can be reduced by source reduction, materials substitution, recycling, incineration, and/or degradation or reduction to low molecular weight compounds. While the value of separated polymers is considerably greater than that of commingled ones, the separation is often difficult and requires an energy investment for “demixing”. With present technology, this has not been justified for more than about 25% of the polymer waste feedstock. For the rest, energy recovery through incineration appears to be the thermodynamically and economically sensible route.
Purification and monolayer study of the thylacoid lipids of moss marchantia polymorpha
Authors: Zaitsev Sergei Yu. , Volchenkova Tatjana A. , Kalabina Nadezda A. , Schaefer Christian , Zubov Vitaly P.
Published: March 2011

The original lipid content of the thylakoid membranes of moss Marchantia polymorpha has been determined for the first time. In particular, the content of SQDG is almost 3 times higher than those for both of the other classes. The ratios for DGDG and MGDG are just a little bit lower than those for green algae, but almost 2 times less than those for plants. The distribution of unsaturated bonds has changed in C18 ‐residues of fatty acids. The total content of C18‐residues in thylacoid lipids have been almost the same but the content of C18:1, C18:2 and C18:3 are altered in the fractions of DGDG, PG and PE. The light stress produces only the quantitative, but no qualitative, changes of the thylakoid lipid composition. The properties of the thylakoid lipids and corresponding fatty acids in the monolayers at the liquid/gas interfaces have been studied. The changes in distribution of unsaturated bonds in C18 residues of fatty acids at light stress have been confirmed by Langmuir method.
A Raman confocal microspectroscopic study on azopolymer holographic diffraction gratings: Photo‐ and mass transport‐induced effects on the molecular orientation
Authors: Labarthet F. Lagugné , Buffeteau T. , Sourisseau C.
Published: March 2011

Using the confocal microspectrometric technique we have recorded various resonance enhanced polarized Raman spectra from the surface profile of a permanent holographic diffraction grating prepared by interfering two circularly contra‐rotating polarized laser beams on a thin amorphous copolymer film containing azobenzene moities (pDRIM‐co‐MMA). Different theoretical equations of the Raman scattering intensities, including a treatment taking account for the effect of the high numerical aperture objective, are thus derived. Calculations and simulations of these equations allow for the first time to extract the second  and fourth  coefficients of the chromophore orientation function in the various regions and to obtain the corresponding information entropy distribution functions. We then discuss both contributions of the photo‐ and mass transport‐ induced effects in the grating formation mechanisms and confirm the existence of a significant dye concentration gradient (δN/N = 5.1±1.1%) in between the top and bottom regions. All the results are consistent with the model of a viscoelastic flow of the polymer involving large pressure gradients and translational diffusion dynamics.
Water‐polysaccharides interactions during apples drying process
Authors: Barra G. , Di Matteo P. , Lamanna R. , Limone G. , Osséo L. Sesti , Vittoria V.
Published: March 2011

In this work the state of water in samples of a food (apple) during the drying process was analyzed.

Low resolution NMR, differential scanning calorimetry (DSC) and sorption measurements were performed on differently dried samples.

It was possible to correlate the NMR proton relaxation time to the water activity aw=P/P0, in order to have an independent method for measuring this parameter. The calorimetric curves showed the thermal transitions of different water populations and the sorption measurements on dry apple gave the fraction of water tightly bond to the structure, which resulted about 30%.
Effect of polymer‐plasticizer interactions on the oxygen permeability of starch‐sorbitol‐water films
Authors: Gaudin S. , Lourdin D. , Le Botlan D. , Ilari J. L. , Forssell P. , Colonna P.
Published: March 2011

This study evaluated the oxygen permeability (O.P.) of starch‐sorbitol‐water films produced by casting. With a sorbitol content <20%, O.P. (0.15 10−16 cm2/s.Pa for 8.8% sorbitol) was lower than for other polymers classically used as oxygen barriers. With a sorbitol content >20%, O.P. (1.6 10−16 cm2/s.Pa for 24.9% sorbitol) was higher than for starch films without a plasticizer. These results were correlated with molecular mobility as determined by time‐domain NMR. Low and high O.P. corresponded respectively to a decrease and an increase of molecular mobility relative to sorbitol content.
Micro‐ and macro‐phase behavior in protein‐polyelectrolyte complexes
Authors: Mattison Kevin W. , Wang Yingfan , Grymonpré Kris , Dubin Paul L.
Published: March 2011

Negatively charged polyelectrolytes such as carboxymethylcellulose, pectin, and alginate are commonly present in food products. These polyelectrolytes serve a variety of functions such as controlling viscosity and stabilizing emulsions. Proteins are also present in many food formulations. Because of their high charge density, polyelectrolytes can be expected to interact with these proteins. Hence, an understanding of the parameters controlling protein‐polyelectrolyte interactions is useful.
Spatially resolved NMR in polymer science
Authors: Blümich Bernhard , Blümler Peter , Gasper Lothar , Guthausen Andreas , Göbbels Volker , Laukemper‐Ostendorf Simone , Unseld Klaus , Zimmer Gisela
Published: March 2011

Selected applications of spatially resolved NMR are presented, which demonstrate the use of the method for investigating applied topics relevant to polymer and materials science. Examples are given for imaging of rigid, soft, and fluid matter. They include characterization and interpretation of electrical aging in poly(ethylene), cross‐link density at the interface of covulcanized elastomer sheets, and cross‐filtration in hollow‐fiber filter modules. A novel NMR detector, the NMR‐MOUSE, has been developed for process and quality control by relaxation measurements. Its use for non‐destructive determination of the glass‐transition temperature by room temperature measurements on elastomer samples is demonstrated.
Materials analysis using confocal Raman microscopy
Authors: Sammon Chris , Hajatdoost Sohail , Eaton Peter , Mura Carine , Yarwood Jack
Published: March 2011

The recent development of Raman microscopes with high optical throughput and very sensitive CCD cameras has led to Raman spectroscopy again competing effectively with FTIR methods for materials analysis. Modern Raman instruments, designed to operate confocally without serious alignment or energy trade‐off problems, allow depth profiling of optically transparent polymers and polymer matrices to be routinely obtained with a spatial resolution of 1–2 μm. The use of such an instrument is illustrated by describing recent work on polymeric material problems including,

1 The distribution and redistribution of small molecules in polymeric matrices.

2 The monitoring of adhesion primer diffusion at a polymer/silica interface.

3 The determination of the extent of interdiffusion and interaction at a polymer/polymer interface.

4 A comparison of confocal and micotoming approaches to polymer laminate analysis.

The range of possible applications is increasing rapidly. It is clear that Raman microscopy will become a very important tool for future materials analysis, both in the polymer area and many other areas.
Perfectly branched and hyperbranched poly(ether amide)s
Authors: Huber Thomas , Voit Brigitte , Wolf Dieter
Published: March 2011

Poly(ether amide) dendrimer segments based on 5‐(2‐aminoethoxy)‐isophthalic acid have been synthesized using the convergent approach and mild reaction conditions. The monodendrons were combined to dendrimers via different core molecules and the resulting properties of the molecules were compared to those of the monodendrons. The melt polycondensation of the AB2 monomers with analog structure resulted first in undefined polymer structures. However, by thermal polyaddition reaction of suitable functionalized oxazoline monomers, well defined hyperbranched poly(ether amide)s with phenol terminal groups could be synthesized.
A new photobase generator containing oxime‐urethane group and its application
Authors: Chae Kyu Ho , Jang Du‐Jeon
Published: March 2011

Photochemical base formation from oxime‐urethane derivatives was observed via pH changes, GC and HPLC analysis, and laser flash photolysis study. Photolysis of these derivatives results in the formation of amines which induce cross‐linking of poly(glycidyl methacrylate) (PGMA) upon heating. Photocross‐linking reaction of the copolymers, containing epoxy and oxime‐urethane groups, were studied by measuring the insoluble fraction of copolymer films under various reaction conditions. Thermal cross‐linking reaction of the copolymer was catalysed by the photogenerated pendant amines. The copolymer containing oxime‐urethane groups which photogenerate aromatic amines can be utilized as an image recording material.
Structure and dynamics of silk fibroin studied with 13C, 15N and 2H solid state NMR
Authors: Asakura Tetsuo , Demura Makoto
Published: March 2011

[1‐13C]Gly, L‐[1‐13C]Ala, [15N]Gly, L‐[15N]Ala, [2,2‐2H2]Gly, L‐[3,3‐2H2]Ser and [3,3,3‐2H3]Ala labeled silk fibroin fibers from Bombyx mori and Samia cynthia ricini silkworms were prepared in order to analyze structure of backbone and dynamics of side chain. The torsion angles ϕ and Ψ were determined from the angular dependent 13C and 15N solid state NMR spectra for uniaxially oriented fiber samples. In addition, the characteristic side chain dynamics of Ser residue determined from solid state 2H NMR measurements was compared with those of Ala and Gly residues.
Hyperbranched aramids by direct polyamidation of two reactant systems: Synthesis and properties
Authors: Russo Saverio , Boulares Alya , Da Rin Andrea , Mariani Alberto , Cosulich Maria Elisabetta
Published: March 2011

Some A2 + B3 and A3 + B3 reagent pairs have been used for the direct polyamidation reaction leading, besides the network formation, to hyperbranched aramid structures. Depending on the chosen experimental conditions, variable amounts of a sol fraction having close similarities with the hyperbranched aramid structures derived from the polyamidation of AB2 monomers, have indeed been obtained. Solubility of the sol fraction in various organic solvents, as well as its thermal properties and its capability of enzyme fixation, have been determined for the various systems under investigation. Future developments are envisaged.
The diffusion of alcohols and water in polyamide 11: A study by fourier‐transform near‐infrared spectroscopy
Authors: Wu Peiyi , Siesler Heinz W.
Published: March 2011

The diffusion of different deuterium‐labeled (OD) low‐molecular‐weight alcohols and D2O in polyamide 11 (PA11) has been investigated by monitoring the NH/ND‐exchange in the polymer by Fourier‐Transform near‐infrared (FTNIR) spectroscopy. The results demonstrate that the diffusion process of the different penetrants is strongly controlled by their molecular structure and geometry. To characterize this phenomenon quantitatively, the diffusion coefficients for the different deuteration agents have been determined for PA11. Furthermore, it could be shown that with this technique the less ordered regions of the polymer can be separated spectroscopically from the crystalline domains which are not accessible for the isotopically labeled diffusants.
Degradation of oligo(lactone) branches linked to poly(methacrylate) networks
Authors: Seidel Peter , Sandner Barbara , Gopp Udo , Schöch Martin , Steurich Simone , Santerre J. Paul
Published: March 2011

Partially resorbable composite materials were developed for bone applications and were prepared by crosslinking copolymerization of oligo(lactone) macromonomers with selected comonomers in the presence of hydroxy apatite. The composites were incubated in aqueous solution of different pH and electrolyte content over a period up to 300 days. The percentage of the released hydroxycarboxylic acid from the oligo(lactone) branches was determined by the titration or by high performance liquid chromatography (HPLC). A catalytic influence of cholesterol esterase (CE) on the hydrolysis of the materials was observed. Determination of CE activity in the presence of the different composite materials showed that the half‐life time of CE was the lowest in the presence of the material undergoing the fastest degradation. After degradation the composite materials have preserved their coherence and have shown higher glass transition temperatures in the dried state than the materials before degradation.
Kinetics and mechanism of biodegradation of (co)polyglycolide sutures
Authors: Belenkaya Bronislava G. , Sakharova Valentina I. , Sinevich Eugene A. , Belousov Sergej I. , Kuptsov Albert H. , Chvalun Sergei N.
Published: March 2011

Biodegradation in vivo of modified and unmodified PG (polyglycolide) and PGL (copolymer glycolide — L — lactide) monofilament sutures were studied using 1H‐ NMR, wide and small angle X‐ray scattering, differential scanning calorimetry (DSC), electron microscopy (EM), Fourier transform (FT) Raman spectroscopy methods. It was found that the process includes a steady‐state and accelerated stages of biodegradation. The suture biostability depends on polymer morphology changing widely over the suture draw ratio. The modification of polymer chain results in an increase in suture useful lifetime without significant changes of complete polymer degradation time. It was also established the important role of weak intermolecular hydrogen bonds such as CH–‐O=C in the suture stability.
New catalysis for fast bulk ring‐opening polymerization of lactide monomers
Authors: Degée Philippe , Dubois Philippe , Jérǒme Robert , Jacobsen Sven , Fritz Hans‐Gerhard
Published: March 2011

The ring‐opening polymerization of lactides has been studied in bulk using either 2‐ethylhexanoic acid tin(II) salt, Sn(Oct)2, or aluminum triisopropoxide, Al(OiPr)3, as the initiator over a wide range of temperature and monomer‐to‐initiator molar ratio. A high increase in the bulk polymerization rate has been observed when the initiator was added with an equimolar amount of a Lewis base, such as triphenylphosphine (P(φ)3) and 4‐picoline (C6H7N) added to Sn(Oct)2 and Al(OiPr)3, respectively. Melt stable polylactides of high molecular weight and reasonably narrow molecular weight distribution have been accordingly prepared. The use of the Sn(Oct)2.P(φ)3 equimolar combination has allowed for reaching an acceptable balance between propagation and depolymerization rates, so that the polymerization is fast enough to be performed through a continuous single‐stage process in a twin‐screw extruder. A global activation mechanism is proposed and discussed by comparison with both investigated initiation systems.
Degradation of polyethylene containing ferric salt and starch
Authors: Gao Jianping , Wang Shaomin , Yu Jiugao , Lin Tong , Wang Xiaodong
Published: March 2011

The degradation of polyethylene containing four different ferric salts was compared, using remaining percentage elongation at break as a parameter; and the degradation process was also evaluated with carbonyl index, or with the formation and concentration of hydroperoxide groups. Starch can act as a synergist during the photodegradation of ferric contained PE film. X‐ray photoelectroscopy analysis shows that part of ferric ions turned into ferrous ions during the degradation process because of the redox reaction of ferric ions with oxygen. When stabilizer was added, the changes from ferric ions to ferrous ions decreased. If the PE samples were exposed to high pressure mercury lamp in the atmosphere of nitrogen gas, the absorption peaks of carbonyl group was not found in IR spectra after several days exposure.
Conformational changes in proteins at interfaces: From solution to the interface, and back
Authors: Norde Willem , Giacomelli Carla E.
Published: March 2011

After adsorption, polymer molecules, including proteins, undergo conformational relaxation. It involves a certain degree of spreading of the polymer molecule over the sorbent surface. Adsorption kinetics experiments reveal that the characteristic time of spreading is much longer for globular proteins than for highly flexible polymers. Based on differential scanning calorimetry it is concluded that the degree of spreading of protein molecules decreases with increasing rate of covering the surface with the protein. It is furthermore inferred that the relaxation does not proceed gradually but rather in steps. According to circular dichroism spectra the relaxed protein molecules still contain a large fraction of ordered structure. As a rule, protein molecules that, by homomolecular exchange, are released from the surface re‐adopt their original structure; however, an exception to this rule is reported.
Intra‐ and inter‐chain fluctuations in entangled polymer melts in bulk and confined to pore channels
Authors: Kimmich Rainer , Fatkullin Nail , Seitter Ralf‐Oliver , Fischer Elmar , Beginn Uwe , Möller Martin
Published: March 2011

It is known that topological restraints by “chain entanglements” severely affect chain dynamics in polymer melts. In this field‐cycling NMR relaxometry and fringe‐field NMR diffusometry study, melts of linear polymers in bulk and confined to pores in a solid matrix are compared. The diameter of the pore channels was 10 nm. It is shown that the dynamics of chains in bulk dramatically deviate from those observed under pore constraints. In the latter case, one of the most indicative signatures of the reptation model is verified 28 years after its prediction by de Gennes: The frequency and molecular mass dependencies of the spin‐lattice relaxation time obey the power law T! ∝ M0 v3/4 on a time scale shorter than the longest Rouse relaxation time τR. The mean squared segment displacement in the pores was also found to be compatible to the reptation law < r2>∝ M−1/2t1/2 predicted for τR < t < τd, where τd is the so‐called disengagement time. Contrary to these findings, bulk melts of entangled polymers show frequency and molecular mass dependencies significantly different from what one expects on the basis of the reptation model. The data can however be described with the aid of the renormalized Rouse theory.
Ion aggregation in polymer gels
Authors: Philippova Olga E. , Khokhlov Alexei R.
Published: March 2011

This brief review deals with our early experimental studies of ion aggregation in polymer gels proceeding via the condensation of counterions on the oppositely charged monomer units of the network with the formation of ion pairs and their clustering into multiplets. The two particular cases of the emergence of ion aggregates are considered: (a) for monovalent counterions in media of low polarity and (b) for multivalent counterions in water.
Load separation principle in determination of J‐R curve for ductile polymers: Suitability of different material deformation functions used in the normalization method
Authors: Bernal Celina , Rink Marta , Frontini Patricia
Published: March 2011

The load separation principle states that the load, P, can be represented as the multiplication of two independent functions: A crack geometry function, G(a), and a material deformation function, H(v). The principle constitutes the theoretical basis for the single‐specimen J‐integral experiment and the incremental calculation of J‐integral crack growth resistance (J‐R) curves. The normalization method is a new method, which assumes load separation and uses characteristic deformation properties of materials to relate load, displacement and crack length in a functional form. From the deformation material function or “material key curve”, J‐R curve can be developed from a single precracking experiment. This investigation deals with the applicability of the load separation criterion to evaluation of ductile fracture mechanics parameters in rubber‐modified polystyrene, polypropylene, rubber‐modified PMMA, ABS resin and high‐density polyethylene in the bending configuration. Different mathematical relationships for the deformation function (power law function, LMN function and combined power law straight line relationship) have been proposed and compared. The resulting J‐R curves are in good agreement with those obtained by the traditional multiple‐specimen technique. The results presented here imply that the use of a single load‐displacement method for evaluation of J‐integrals for ductile polymers is possible and hence also the normalization method can be used for evaluation of J‐R curves from a single‐test record.
Sequences distribution of poly(ethylene terephthalate‐isophthalate) copolymers: Experimental TREF study and numerical simulation
Authors: Lodefier Philippe , Daoust Daniel , Jonas Alain M. , Legras Roger
Published: March 2011

The fractionation of a statistical copolyester made of poly(ethylene terephthalate‐ isophthalate) has been performed using Temperature Rising Elution Fractionation (TREF). TREF fractions were analyzed by size exclusion chromatography, thermal analysis, 1H‐nuclear magnetic resonance and small angle X‐Ray diffractometry. Results show that the fractions exhibit both interchain and intrachain defect distribution. As the intrachain defect distribution can not be determined by experimental techniques, a computer simulation based on the determination of terephthalic sequences length in a virtual polymeric distribution was performed. The simulated chains were constructed using a stochastic process. The analysis of the results obtained on the distribution of the simulated sequences in the polymer correlates quantitatively well between the new fractionation mechanism proposed for copolyesters and the experimental results.
Effect of the corona treatment and of the 1,4‐cyclohexanedimethanol on the surface characteristics of the poly(ethylene terephthalate) film
Authors: Pinto Georgia Vieira De Vasconcelos Vilaça , De Abreu César Augusto Moraes , Knoechelmann Augusto , De Almeida Yêda Medeiros Bastos
Published: March 2011

Several techniques have been applied for the characterization of three PET films surfaces: homopolymer PET film, corona treated PET film and a poly(ethylene terephthalate‐co‐1,4‐cyclohexanedimethanol) film. The objective of this work is to investigate and to apply precise and mutually complementary techniques which give detailled information about theses surfaces, as there are few papers with global and conclusive results. The film surfaces were investigated to support the development of new products and envisage new apllications to the existent films.

Scanning electron micrographs, attenuated total reflection Fourier transform infrared spectroscopy (FTIR‐ATR) and multiple internal reflection Fourier transform infrared spectroscopy (FTIR‐MIR) spectra show that the chemical composition, topography and surface roughness of the films are different. The corona‐treated PET film shows high surface tension value due to the major contribution on the polar groups and oxidation level acquired. The copolyester film is much less crystalline than the other films analyzed, as demonstrated by refractive index measurements and X‐ray photoelectron spectroscopy (XPS). The amorphous structures obtained and the high tension level of the corona‐treated films provide a better understanding of the adhesion phenomena.

In view of results obtained, one can assume that corona treated films owing to its higher surface tension and films with CHDM owing to its surface amorphization should provide manufacturing industries better processing conditions than films without surface treatment and also higher levels of adhesion to paints and coatings.
“Theory of mind” is impaired in Huntington's disease
Authors: Brüne Martin , Blank Karina , Witthaus Henning , Saft Carsten
Published: March 2011

Background:

Huntington's disease (HD) is an autosomal dominant degenerative brain disorder that is characterized by motor, cognitive, and affective symptoms. There is, to some, degree, phenomenological overlap with schizophrenia. Schizophrenia patients are frequently impaired in “theory of mind” (ToM), that is, the ability to reflect on the mental states of self and others, with mixed evidence for a ToM deficit in HD.

Methods:

We examined ToM and neurocognitive functioning in 25 patients diagnosed with HD. For comparison, 25 patients with schizophrenia and 25 healthy controls, matched for age and gender, were included.

Results:

Patients with HD were impaired in ToM relative to controls. The pattern of neurocognitive deficits including ToM strikingly resembled the one found in schizophrenia, suggesting a selectively impaired ToM. In contrast to previous schizophrenia research, ToM was not associated with functional measures on the Unified Huntington's Disease Rating Scale (UHDRS).

Conclusions:

The present study shows that patients with HD have deficits in ToM similar to schizophrenia. The association of impaired ToM with function needs to be established in future studies using rating scales that more specifically address interpersonal problems. © 2011 Movement Disorder Society
Parkinson's syndrome and Parkinson's disease in mitochondrial disorders
Authors: Finsterer Josef
Published: March 2011

In the majority of cases, mitochondrial disorders are multisystem conditions that most frequently affect the skeletal muscle, followed by the central nervous system. One of the clinical manifestations of central nervous system involvement is Parkinson's syndrome (PS). Evidence for an association of mitochondrial defects with PS comes from mitochondrial disorder patients who have developed Parkinson's syndrome and from Parkinson's syndrome patients who have developed a mitochondrial disorder. In addition, there are a number of patients with Parkinson's syndrome or Parkinson's disease (PD) who later develop subclinical immunohistological or biochemical indications of mitochondrial defects or accumulates mitochondrial DNA mutations within various cerebral regions. There are also Parkinson's syndrome patients who present with elevated cerebrospinal‐fluid lactate by magnetic resonance spectroscopy. Furthermore, it has been shown that mutations in genes causing PD, such as PINK1, parkin, DJ1, alpha‐synuclein, and LRRK2, also cause mitochondrial dysfunction, which is one of the reasons why they are called mitochondrial nigropathies. Parkinson's syndrome in patients with a mitochondrial disorder may also result from oxidative stress or exogenous toxins. Treatment of mitochondrial Parkinson's syndrome is not at variance with the treatment of Parkinson's syndrome due to other causes, but because of the multisystem nature of mitochondrial disorders, mitochondrial Parkinson's syndrome requires additional therapeutic support. © 2011 Movement Disorder Society
Kinetic Analysis of Nanocomposites Prepared in situ Consisting of an Aliphatic Biodegradable Polyester and Fumed Silica Nanoparticles
Authors: Kostoglou Margaritis , Bikiaris Dimitrios
Published: March 2011

PPSu/fumed silica nanocomposites are prepared by in situ polymerization using 0.25, 0.5, 1, and 2.5 wt.‐% SiO2. The SiO2 content affects both esterification and polycondensation reactions directly. By increasing the SiO2 content in esterification, the rate of water production decreases. The reaction between PPSu and silanol groups of SiO2 is confirmed by XPS analysis. A quantitative model is developed to describe the influence of the SiO2 particles on the water production rate during esterification. The main reason for this is the adsorption of the produced water on the particles. The rate of adsorption/desorption processes is assumed to be comparable to the water evaporation rate in order to reproduce the experimental water production curves.

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Water sorption characteristics of poly(2‐hydroxyethyl acrylate)/silica nanocomposite hydrogels
Authors: Pandis Christos , Spanoudaki Anna , Kyritsis Apostolos , Pissis Polycarpos , Hernández José Carlos Rodríguez , Gómez Ribelles Jose Luis , Monleón Pradas Manuel
Published: March 2011

Water sorption in hydrogels based on nanocomposites of poly(2‐hydroxyethyl acrylate) (PHEA) and silica, prepared by simultaneous polymerization and sol‐gel process, were studied gravimetrically over wide ranges of silica content, both below and above the percolation threshold of about 15% wt for the formation of a continuous inorganic network interpenetrated with the organic network. Measurements were performed at room temperature from the vapor phase, both at equilibrium and dynamic, for selected values of water activity αw between 0 and 0.95, and from the liquid phase. In the nanocomposite hydrogels, the overall water uptake from the vapor phase is practically the same as in pure PHEA below the percolation threshold, whereas it is reduced above the percolation threshold, in particular at high αw values where swelling becomes significant. Water clustering sets in at around 14 vol % (10 wt %) of water independently of composition, whereas the mean value of water molecules in a cluster decreases at high silica contents. In immersion experiments water uptake decreases as silica content increases to the percolation threshold of about 15 wt % and is then almost independent of composition. A scheme is proposed, which explains these results in terms of the existence of micelles, where a number of hydrophilic hydroxy groups are linked together, and their disentaglement by immersion into water. Diffusion coefficients of water depend on water content and are reduced on addition of silica above the percolation threshold. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
GSTpi modulates JNK activity through a direct interaction with JNK substrate, ATF2
Authors: Thévenin Anastasia F. , Zony Chati L. , Bahnson Brian J. , Colman Roberta F.
Published: March 2011

Human GSTpi, an important detoxification enzyme, has been shown to modulate the activity of JNKs by inhibiting apoptosis and by causing cell proliferation and tumor growth. In this work, we describe a detailed analysis of the interaction in vitro between GSTpi and JNK isoforms (both in their inactive and active, phosphorylated forms). The ability of active JNK1 or JNK2 to phosphorylate their substrate, ATF2, is inhibited by two naturally occurring GSTpi haplotypes (Ile105/Ala114, WT or haplotype A, and Val105/Val114, haplotype C). Haplotype C of GSTpi is a more potent inhibitor of JNK activity than haplotype A, yielding 75–80% and 25–45% inhibition, respectively. We show that GSTpi is not a substrate of JNK, as was earlier suggested by others. Through binding studies, we demonstrate that the interaction between GSTpi and phosphorylated, active JNKs is isoform specific, with JNK1 being the preferred isoform. In contrast, GSTpi does not interact with unphosphorylated, inactive JNKs unless a JNK substrate, ATF2, is present. We also demonstrate, for the first time, a direct interaction: between GSTpi and ATF2. GSTpi binds with similar affinity to active JNK + ATF2 and to ATF2 alone. Direct binding experiments between ATF2 and GSTpi, either alone or in the presence of glutathione analogs or phosphorylated ATF2, indicate that the xenobiotic portion of the GSTpi active site and the JNK binding domain of ATF2 are involved in this interaction. Competition between GSTpi and active JNK for the substrate ATF2 may be responsible for the inhibition of JNK catalysis by GSTpi.
Probing the different chaperone activities of the bacterial HSP70‐HSP40 system using a thermolabile luciferase substrate
Authors: Sharma Sandeep K. , De Los Rios Paolo , Goloubinoff Pierre
Published: March 2011

During mild heat–stress, a native thermolabile polypeptide may partially unfold and transiently expose water‐avoiding hydrophobic segments that readily tend to associate into a stable misfolded species, rich in intra‐molecular non‐native beta‐sheet structures. When the concentration of the heat‐unfolded intermediates is elevated, the exposed hydrophobic segments tend to associate with other molecules into large stable insoluble complexes, also called “aggregates.” In mammalian cells, stress‐ and mutation‐induced protein misfolding and aggregation may cause degenerative diseases and aging. Young cells, however, effectively counteract toxic protein misfolding with a potent network of molecular chaperones that bind hydrophobic surfaces and actively unfold otherwise stable misfolded and aggregated polypeptides. Here, we followed the behavior of a purified, initially mostly native thermolabile luciferase mutant, in the presence or absence of the Escherichia coli DnaK‐DnaJ‐GrpE chaperones and/or of ATP, at 22°C or under mild heat–stress. We concomitantly measured luciferase enzymatic activity, Thioflavin‐T fluorescence, and light‐scattering to assess the effects of temperature and chaperones on the formation, respectively, of native, unfolded, misfolded, and/or of aggregated species. During mild heat‐denaturation, DnaK‐DnaJ‐GrpE+ATP best maintained, although transiently, high luciferase activity and best prevented heat‐induced misfolding and aggregation. In contrast, the ATP‐less DnaK and DnaJ did not maintain optimal luciferase activity and were less effective at preventing luciferase misfolding and aggregation. We present a model accounting for the experimental data, where native, unfolded, misfolded, and aggregated species spontaneously inter‐convert, and in which DnaK‐DnaJ‐GrpE+ATP specifically convert stable misfolded species into unstable unfolded intermediates. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Moisture transport in midlatitude cyclones
Authors: Boutle I. A. , Belcher S. E. , Plant R. S.
Published: March 2011

We discuss how synoptic‐scale variability controls the transport of atmospheric water vapour by midlatitude cyclones. Idealized simulations are used to investigate quantitatively which factors determine the magnitude of cyclone moisture transport. It is demonstrated that large‐scale ascent on the warm conveyor belt and shallow cumulus convection are equally important for ventilating moisture from the boundary layer into the free troposphere, and that ventilated moisture can be transported large distances eastwards and polewards by the cyclone, before being returned to the surface as precipitation.

The initial relative humidity is shown to have little effect on the ability of the cyclone to transport moisture, whilst the absolute temperature and meridional temperature gradient provide much stronger controls. Scaling arguments are presented to quantify the dependence of moisture transport on large‐scale and boundary‐layer parameters. It is shown that ventilation by shallow convection and warm‐conveyor‐belt advection vary in the same way with changes to large‐scale parameters. However, shallow convective ventilation has a much stronger dependence on boundary‐layer parameters than warm‐conveyor‐belt ventilation. Copyright © 2011 Royal Meteorological Society
Investigations of hyperfine structure and isotope shift predictions in Hf II
Authors: Bouazza Safa
Published: March 2011

The fine structure of the even‐parity low configurations of singly ionized hafnium has been reanalyzed by simultaneous parameterization of the one‐ and two‐body interactions for the model space (5d + 6s)3. Using the calculated eigenfunctions, the magnetic‐dipole A hyperfine constants for the whole 37 existing levels of the model space were predicted and compared partially with those obtained using relativistic configuration‐interaction approach. Moreover, combined with experimental data, previously given in the literature, and pseudo‐relativistic Hartree–Fock estimates, the field shifts (FSs) and specific mass shifts (SMSs) of numerous configurations are deduced: FS(5d16s2) = 2265 MHz, FS(5d3) = −1958 MHz, FS(5d16p2) = −1696 MHz, FS(6s26p1) = 3135 MHz, and SMS(5d16s2) = −78 MHz, SMS(5d3) = 64 MHz, SMS(6s26p1) = −228 MHz, referred to 5d26s for the pair 178Hf–180Hf. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Definition of an isodesmicity index from G3B3 energy components
Authors: Lories Xavier , Vandooren Jacques , Peeters Daniel
Published: March 2011

In this work, we define an isodesmicity index, which allows the evaluation of the conservation of the error within a given bond conserving reaction. This index is reaction‐specific and, therefore, does not rely on the nature of the reference systems. Several aspects of the index are tested, to verify that this measurement shows the desired behavior. The index is a tool, which should allow the user to establish the “best” bond conserving process for, for instance, the determination of a heat of formation. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
The lowest order relativistic corrections for the hydrogen molecule
Authors: Datta Sumita , Alexander S. A. , Coldwell R. L.
Published: March 2011

We have calculated the lowest order relativistic corrections for the X 1Σ, B1Σ, a3Σ, b3Σ, I1Πg, C1Πu, i3Πg, c3Πu, J1Δg, and j3Δg states of the hydrogen molecule using variational Monte Carlo methods and compact, explicitly correlated trial wavefunctions. Our values are in good agreement with earlier calculations on the X1Σ and B1Σ states. For the other states, our work provides the first estimate of these properties. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Sustained treatment: Implications for treatment timescales associated with source‐depletion technologies
Authors: Adamson David T. , McGuire Travis M. , Newell Charles J. , Stroo Hans
Published: March 2011

Sustained treatment is an emerging concept used to describe enhancements in attenuation capacity after the conclusion of the active treatment period for a given source‐depletion technology. The term includes mechanisms that lead to contaminant transformation or destruction over extended periods of time, such as endogenous biomass decay, slow diffusion of remedial amendments from low‐permeability zones, and the formation of reactive mineral species. This “value‐added” treatment continues after the end of capital expenditures at a site, and it provides additional insight in determining if monitored natural attenuation is a viable long‐term option for a site. This article identifies several sustained treatment mechanisms, examines technology‐specific factors that contribute to sustained treatment, and explores the potential timescales of sustained treatment relative to active treatment. As demonstrated in post‐treatment site data obtained during a comprehensive source‐depletion technology performance survey, enhanced bioremediation is the most promising in promoting sustained treatment, and this beneficial effect can extend for several years due to factors such as slow biomass decay. There is little evidence that other commonly used technologies (thermal treatment, in situ chemical oxidation, surfactant‐enhanced remediation, or cosolvent flushing) result in any significant sustained treatment. An exception would be a cosolvent flushing project where large quantities of biodegradable cosolvent are left in the subsurface at the end of the project, which could result in sustained long‐term dechlorination activity. In the case of in situ chemical oxidation, factors that contribute to a higher incidence of concentration rebound mask any potential sustained treatment effects. © 2011 Wiley Periodicals, Inc.
Field study of biostimulation and bioaugmentation for remediation of tetrachloroethene in groundwater
Authors: Santharam Sathishkumar , Ibbini Jwan , Davis Lawrence C. , Erickson Larry E.
Published: March 2011

A pilot field study was conducted for remediation of a tetrachloroethene (PCE)‐contaminated site in Manhattan, Kansas. Prior to the pilot study, the PCE concentration in groundwater at the pilot‐study area was about 15 mg/L (91 µM). Nutrient solution comprising soy oil methyl esters (SOME), lactate, and yeast extract was added in the pilot‐study area for biostimulation on August 18, 2005 (day 0). Potassium bromide (KBr) was added in the nutrient solution as a tracer. PCE was converted to dichloroethene (DCE) under these conditions. KB‐1, a consortium of Dehalococcoides, and a second dose of nutrient solution were added on day 56. After addition of KB‐1, both PCE and DCE concentrations decreased. Nutrients were again injected on day 197 (with KBr). On day 348, cheese whey was injected. Soluble nutrients and KB‐1 migrated downstream, affecting PCE and DCE concentrations at downgradient wells; however, KB‐1 moved slower than the aqueous phase. The total chlorinated ethenes (CEs) decreased by about 80 percent in the pilot‐study area due to bioremediation. Biodegradation of CEs continued for several months after the addition of nutrients. A portion of the insoluble SOME was retained in the vicinity of the injection wells and provided a long‐time source of nutrients and electron donors that supported degradation of PCE. A mixture of SOME and soluble substrates worked effectively in this study. © 2011 Wiley Periodicals, Inc.
Building capacity for community‐based brownfields remediation and redevelopment: An innovative technical assistance model
Authors: Lowrie Karen W. , Solitare Laura , Himmelfarb Katie
Published: March 2011

Thousands of unaddressed brownfields sites remain in our nation's poorest urban neighborhoods, despite almost two decades of federal and state attention to cleaning up and redeveloping these sites. Many of these neighborhoods have active community‐based organizations (CBOs) whose mission it is to improve the quality of life for disadvantaged residents whose lives are negatively impacted by these decaying, contaminated properties. Under the assumption that greater involvement of community organizations, specifically community development corporations (CDCs), would help to spur increased attention to and progress toward remediating these sites, we developed a pilot technical assistance program to build CDC capacity to facilitate or actually undertake brownfields redevelopment projects. This article describes the process of development and the program's content and structure and evaluates the program based on a pilot test conducted with two CDCs in a major US city. Future prospects for expansion of this type of program are discussed. © 2011 Wiley Periodicals, Inc.
Public preferences for environmental management practices at DOE's nuclear waste sites
Authors: Greenberg Michael , Mayer Henry , Powers Charles
Published: March 2011

Residents who lived within 50 miles of one of six major US Department of Energy nuclear waste sites were asked in 2005 and again in 2010 to rate environmental management options. Respondents expressed strong preference for continuously sampling the air and water, monitoring worker health, and providing training and equipment to local responders. They strongly supported some site restrictions, such as making sure that the federal government owns the site until no more hazards are present, keeping visitors and recreational users off the site, and requiring government officials to report information to community representatives. The public was much more equivocal about other options, such as restricting new nuclear‐related activities and requiring site managers to live near sites. The authors summarize factors that lead to these public preferences and discuss five population types encountered at these and perhaps other waste management sites. © 2011 Wiley Periodicals, Inc.