bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical and surface properties of whey protein isolate coatings on plastic films as influenced by substrate, protein concentration, and plasticizer type
Authors: Hong Seok‐In , Han Jung H. , Krochta John M.
Published: February 2004

Composite film structures of common plastic polymers including polypropylene (PP) or poly(vinyl chloride) (PVC) with whey protein isolate (WPI) coatings may be obtained by a casting method. Optical and surface properties of the resulting WPI‐coated plastic films, as affected by protein concentration and plasticizer type, were investigated to examine the biopolymer coating effects on surface modification with polymeric substrates of opposite polarity. The measured properties involved specular gloss, color, contact angle, and critical surface energy. Regardless of the substrates, WPI‐coated films possessed excellent gloss and no color, as well as good adhesion between the coating and the substrate when an appropriate plasticizer was added to the coating formulations. The protein concentration did not significantly affect gloss of WPI‐coated plastic films. Among five plasticizers applied, sucrose conferred the most highly reflective and homogeneous surfaces to the coated films. The WPI coatings were very transparent and the coated films with various protein concentrations and plasticizers showed no noticeable changes in color. Experimental results suggest that WPI coatings formulated with a proper plasticizer can improve the visual characteristics of the polymeric substrate and enhance water wettability of the coated plastic films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 335–343, 2004
Synthesis and properties of polyurethane resins based on liquefied wood
Authors: Wei Yuping , Cheng Fa , Li Houping , Yu Jiugao
Published: February 2004

Three polyurethane resins were synthesized from liquefied wood and three diisocyanates, i.e., TDI, IPDI, and HDI. The liquefied wood was obtained by the liquefaction of benzylated wood wastes using Dibasic esters (DBE) as solvent with hydrochloric acid as catalyst for 3 h, at 80°C. The thermal stability and microphase morphology of polyurethane films were investigated by TG, DSC, WAXD, and SEM methods. The experimental results indicated that polyurethane resins from liquefied wood had higher thermal stability than traditional ones, and the special structure and the difference of chemical structure of diisocyanates resulted in the crytallinity and microphase separation of obtained polyurethanes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 351–356, 2004
Morphology and mechanical properties of layered silicate reinforced natural and polyurethane rubber blends produced by latex compounding
Authors: Varghese S. , Gatos K. G. , Apostolov A. A. , Karger‐Kocsis J.
Published: February 2004

Natural rubber (NR), polyurethane rubber (PUR), and NR/PUR‐based nanocomposites were produced from the related latices by adding a pristine synthetic layered silicate (LS; sodium fluorohectorite) in 10 parts per hundred parts rubber (phr). The dispersion of the LS latices in the composite was studied by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Further information on the rubber/LS interaction was received from Fourier transform infrared spectroscopy (FTIR) and dynamic mechanical thermal analysis (DMTA). Tensile and tear tests were used to characterize the performance of the rubber nanocomposites. It was found that LS is more compatible and thus better intercalated by PUR than by NR. Further, LS was preferably located in the PUR phase in the blends, which exhibited excellent mechanical properties despite the incompatibility between NR and PUR. Nano‐reinforcement was best reflected in stiffness‐ and strength‐related properties of the rubber composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 543–551, 2004
Permeability of semicrystalline polymers to toluene/methanol mixture
Authors: Gagnard Christelle , Germain Yves , Keraudren Patrick , Barrière Benoît
Published: February 2004

In this article, we analyze the effect of the alcohol content in gasoline on the permeability of four semicrystalline polymers used in automobile fuel systems. More specifically, we are interested in the methanol/toluene mixture as a “binary” model of a complex gasoline to understand the selectivity brought about, in front of these solvents, by the nature of the polymer. We developed a permeation cell coupled to a chromatograph to analyze the composition of escaping toluene and methanol. These experiments allow us to demonstrate the strong “positive synergy” that exists between the flows of the methanol and the toluene when they are mixed, compared to the flows of these solvents on their own. This phenomenon is notably highlighted on polymers of very different kinds (PA12, PVDF, HDPE, EVOH) and, in light of recent theoretical developments, we can consider that this property is general, because this “positive synergy” is a consequence of the evolution of the solubility of the mixture of solvents in the polymer film, and more particularly, of the highly positive value of the Flory‐Huggins interaction coefficient between methanol and toluene. These experimental data allow one to better understand and predict the permeability behavior of the polymers in front of complex gasolines. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 676–682, 2004
Reconfiguring control in library collection development: A conceptual framework for assessing the shift toward electronic collections
Authors: Covi Lisa M. , Cragin Melissa H.
Published: February 2004

Academic and special libraries are in the midst of a shift toward hybrid collections. This shift from collection ownership to an information access model supports the distributed nature of learning and work. However, unanticipated consequences of these changes are emerging. One confounding result is a visible pattern of discontinuities in collections, with unique features for electronic products. Patterns of discontinuities encountered included the occurrence of intermittent holes and unintentionally masked information. This has both immediate and long‐term implications for library users and services, and there are not yet coherent measures to assess these sorts of outcomes. A framework is required for the systematic evaluation of the effects of new systems such as bundled electronic resources. This research suggests that evaluating both use and non‐use of electronic collections will supplement other acquisitions and service measures to support long‐range planning and decision‐making.
One‐Step Synthesis of Hypoxanthine from Glycinamide and Diformylurea
Authors: Lagoja Irene M. , Herdewijn Piet
Published: February 2004

Because of their easy availability and their relative chemical stability, urea, formic acid, and glycine might have played a role in the assembly process of nucleobases. In this paper, a short reaction path is described to prepare hypoxanthine starting from the above mentioned precursors. The formation of hypoxanthine has been verified by high‐resolution mass spectrometry with the 15N‐labelled urea as starting material, and HPLC analysis. The yield of this condensation reaction has been determined spectrophotometrically.
A Structure‐Information Approach to the Prediction of Biological Activities and Properties
Authors: Hall Lowell H.
Published: February 2004

The structure‐information approach to quantitative biological modeling and prediction is presented in contrast to the mechanism‐based approach. Basic structure information is developed from the chemical graph (connection table). The development, beginning with information explicit in the connection table (element identity and skeletal connections), leads to significant structure information useful for establishing sound models of a wide range of properties of interest in drug design. Skeletal branching patterns and valence state definition lead to relationships for valence‐state electronegativity and atom or group molar volumes. Based on these important aspects of molecules, both the electrotopological state (E‐State) and molecular‐connectivity structure descriptors (χ indices) are developed. A summary of QSAR models indicates the wide range of applicability of these structure descriptors and the predictive quality of QSAR models for protein binding, HIV‐1 protease inhibition, bloodbrain‐barrier partitioning, fish toxicity, carcinogenicity risk, structure space for similarity searching, and data mining. These models are independent of three‐dimensional structure information and are directly interpretable in terms of structure information useful to the drug‐design process.
Enhanced Fluorescence of Remote Functionalized Diaminodicyanoquinodimethanes in the Solid State and Fluorescence Switching in a Doped Polymer by Solvent Vapors
Authors: Jayanty S. , Radhakrishnan T. P.
Published: February 2004

Remote functionalized zwitterionic diaminodicyanoquinodimethanes are found to exhibit a dramatic enhancement of light emission in the solid state and when doped in polymer films, as compared to the solution state. Crystal structure analysis of prototypical molecules reveals the role of the remote functionality in the solid state molecular organization. Semiempirical quantum chemical computations provide a viable model to explain the interesting phenomenon of fluorescence enhancement as arising from the inhibition of geometry relaxation of the vertical excited state to a nonemitting state. The reversible switching of a doped polymer film fluorescence triggered by solvent vapors is demonstrated.
Lanthanum Endohedral Metallofulleropyrrolidines: Synthesis, Isolation, and EPR Characterization
Authors: Cao Baopeng , Wakahara Takatsugu , Maeda Yutaka , Han Aihong , Akasaka Takeshi , Kato Tatsuhisa , Kobayashi Kaoru , Nagase Shigeru
Published: February 2004

Lanthanum endohedral metallofulleropyrrolidines have been synthesized for the first time through addition of an azomethine ylide to La@C82‐A in toluene. It was found that the addition reaction is very efficient and, to some extent, regioselective. Two major endohedral metallofulleropyrrolidines, a monoadduct and a bisadduct of La@C82‐A with abundance ratio of ∼1:0.4, have been isolated by HPLC chromatography and characterized by mass spectrometry, UV/Vis‐NIR absorption, and EPR spectroscopy. The electronic structure of La@C82‐A has been modified slightly upon monoaddition and significantly upon bisaddition of the pyrrolidines.
Supramolecular Photomagnetic Materials: Photoinduced Dimerization of Ferrocene‐Based Polychlorotriphenylmethyl Radicals
Authors: Ratera Imma , Ruiz‐Molina Daniel , Vidal‐Gancedo José , Novoa Juan J. , Wurst Klaus , Letard Jean‐François , Rovira Concepció , Veciana Jaume
Published: February 2004

New ferrocenyl Schiff‐base polychlorotriphenylmethyl radicals have been synthesized and characterized. The imino group of one such radical undergoes an irreversible trans to cis structural isomerization induced by light. Such photoinduced isomerization has been monitored by UV/Vis and ESR spectroscopy and also monitored by HPLC. ESR frozen solution experiments at low temperature revealed that the cis isomer dimerizes, showing a strong antiferromagnetic interaction. Although numerous photochromic supramolecular systems have been described, such a photoinduced self‐assembly process represents the first example of a one‐way photoswitchable magnetic system in which a conversion between a doublet and a singlet ground state species is promoted by a photoinduced dimerization process driven by the formation of hydrogen bonds. DFT calculations on the minimized structure and on the rotational barriers have been performed to establish the origin of such behavior. The effect of the substituents and the media polarity on the photoisomerization of this imine chromophore have also been studied. It has been observed that the efficiency of the process is markedly dependent on the presence and characteristics of electron‐donor and electron‐acceptor substituents of the ferrocenyl Schiff‐base polychlorotriphenylmethyl radicals as well as on the polarity of the solvent.
Ti2: Accurate Determination of the Dissociation Energy from Matrix Resonance Raman Spectra and Chemical Interaction With Noble Gases
Authors: Himmel Hans‐Jörg , Bihlmeier Angela
Published: February 2004

UV‐visible and resonance Raman spectra of Ti2 isolated in Ar, Kr, and Xe matrices at temperatures of 10 K were measured by using the 514 nm line of an Ar ion laser. The data show that the Ti2 molecule interacts strongly with Xe, leading to a significant weakening of the TiTi bond strength. The f(TiTi) force constant decreases in the series Ar>Kr>Xe, from 232.8 Nm−1 in Ar and 225.5 Nm−1 in Kr to 199.7 Nm−1 in Xe. Additional experiments in an Ar matrix containing 2 % of Xe indicate the formation of a molecule of the formula Ti2Xe. Our spectra for Ti2 in an Ar matrix give evidence for several previously not observed members of the Stokes progression. The sum of experimental data allows for an improved estimation of the dissociation energy on the basis of a LeRoy–Bernstein–Lam analysis. A dissociation energy of 1.18 eV was derived from this analysis. The UV‐visible data give evidence of the vibrational levels of an excited state of Ti2.
Kompressionsverhalten und Fließkennwerte eines kohäsiven Kalksteinmehls im Mitteldruckbereich
Authors: Grossmann L. , Tomas J.
Published: February 2004

No abstracts.
Entwicklung einer nahezu idealen elektrostatischen Trennapparatur für Gas und Partikel
Authors: Asbach C. , Kuhlbusch T. A. J. , Fissan H.
Published: February 2004

No abstracts.
Verdrängungsströmung und Partikelverdrängung zwischen Mahlkugeln bzw. Mahlkugel und Wand
Authors: Mende G. , Bernotat S. , Schwedes J.
Published: February 2004

No abstracts.
Simulation der Aufschlusszerkleinerung eines Partikelverbundstoffes mittels der Diskrete‐Elemente‐Methode
Authors: Schubert W. , Khanal M. , Tomas J.
Published: February 2004

No abstracts.
Simulation des Ablöseverhaltens poröser Filterkuchen in der Oberflächenfiltration
Authors: Wien G. , Sonnenberg J.‐P. , Schmidt E.
Published: February 2004

No abstracts.
Antibodies to non‐bilayer phospholipid arrangements induce a murine autoimmune disease resembling human lupus
Authors: Baeza Isabel , Leyva Emma , Campos Begoña , Lara Mónica , Ibáñez Miguel , Farfán Norberto , Orozco Héctor , Flores‐Romo Leopoldo , Hernández‐Pando Rogelio , Wong Carlos
Published: February 2004

Antibodies recognizing non‐bilayer phospholipid arrangements (NPA) in membrane models and in cell membranes in vivo, triggered an autoimmune‐like disease in mice. This exhibited features similar to human lupus and was induced by injecting mice either with the H308 monoclonal antibody specific to NPA, with sera from mice which already had developed the autoimmune disease, or withliposomes treated with the NPA inductors chlorpromazine or procainamide; or with these NPA inductors alone. All these procedures revealed the involvement of antibodies to non‐bilayer phospholipids in inducing this autoimmune‐like disease. Unraveling the mechanisms of these antibodies might contribute to a better understanding of the molecular and immunological basis of autoimmune diseases like lupus and, hopefully, towards the development of better therapeutic strategies.
Introducing a mouse model for pre‐eclampsia: adoptive transfer of activated Th1 cells leads to pre‐eclampsia‐like symptoms exclusively in pregnant mice
Authors: Zenclussen Ana C. , Fest Stefan , Joachim Ricarda , Klapp Burghard F. , Arck Petra C.
Published: February 2004

Pre‐eclampsia (PE) is the most severe pregnancy‐related disease, leading to high maternal and fetal morbidity/mortality. Immunological imbalances associated with endothelial cell dysfunction have been hypothesized as a cause for the onset and perpetuation of PE. Valid and reliable animal models are urgently required to test this hypothesis and to better understand the mechanisms underlying PE. We developed a novel PE‐model by adoptively transferring activated BALB/c Th1‐like splenocytes into allogeneically pregnant BALB/c female mice during late gestation; the model mimicked the symptoms of PE, i.e. increased blood pressure and glomerulonephritis accompanied by proteinuria. Interestingly, these PE‐like symptoms were not detectable in non‐pregnant recipients of activated Th1‐like cells. Adoptive cell transfer adversely affected the outcome of pregnancy by increasing fetal rejection, with uterine immune cells showing an inflammatory profile. In conclusion, we have established a valid and reliable PE mouse model, which opens vast opportunities for therapeutic interventions.
Analysis of the activating receptors and cytolytic function of human natural killer cells undergoing in vivo differentiation after allogeneic bone marrow transplantation
Authors: Vitale Chiara , Chiossone Laura , Morreale Giuseppe , Lanino Edoardo , Cottalasso Francesca , Moretti Sara , Dini Giorgio , Moretta Lorenzo , Mingari Maria Cristina
Published: February 2004

Patients undergoing allogeneic bone marrow transplantation offer a unique system to analyze NK cell development in vivo. We analyzed NK cells from 23 such patients to assess the acquisition of activating receptors. Four patients displayed an immature NK cell surface phenotype at engraftment, as their cells were CD16–KIR– and NKG2D– but expressed low levels of NKp46, NKp30, 2B4 and NKG2A. These NK cells had particularly low cytolytic activity against the HLA‐class‐I– melanoma F01 cell line and the 721‐221 EBV‐infected B cell line. Moreover, cytoxicity was inhibited upon mAb‐mediated crosslinking of 2B4. Analysis of NK cells at day 30 after bone marrow transplantation revealed the occurrence of both phenotypic and functional maturation. These data are in agreement with a previous in vitro study showing that immature NK cell precursors express CD16, NKG2D and KIR only at a late stage of differentiation and also express inhibitory 2B4. Our present study allows a better understanding of the NK cell differentiation in vivo.
The chemokine receptor CCR7 controls lymph node‐dependent cytotoxic T cell priming in alloimmune responses
Authors: Höpken Uta E. , Droese Jana , Li Jian‐Ping , Joergensen Joanne , Breitfeld Dagmar , Zerwes Hans‐Günter , Lipp Martin
Published: February 2004

The chemokine receptor CCR7 and its ligands regulate migration and colocalization of T cells and mature dendritic cells to and within secondary lymphoid organs. The requirement of CCR7 in efficient priming of allospecific cytotoxic CD8+ T cells is poorly characterized. Here, we demonstrate a role for CCR7 in the initiation of an alloimmune response and in the development of transplant rejection. Remarkably, in a model of acute allogeneic tumor rejection, CCR7–/– mice completely failed to reject subcutaneously injected MHC class I mismatched tumor cells and cytotoxic activity of allospecific T cells was severely compromised. When solid tumors derived from wild‐type mice were transplanted, recipient CCR7–/– mice were capable of rejecting the allografts. In contrast, tumor allografts transplanted from CCR7–/– donors onto CCR7–/– recipients showed allograft survival up to 28 days, suggesting a critical function of CCR7 on donor‐type passenger leukocytes in the initiation of cytotoxic CD8+ T cell responses. In a heterotopic heart transplantation model CCR7 deficiency resulted in significantly prolonged but not indefinite allograft survival. Additional prolongation of graft survival was observed when hearts from CCR7–/– mice were used as donor organs. Our results define a key role for CCR7 in allogeneic T cell priming within the context of draining lymph nodes.
Maintenance of memory CTL responses by T helper cells and CD40‐CD40 ligand: antibodies provide the key
Authors: Bachmann Martin F. , Hunziker Lukas , Zinkernagel Rolf M. , Storni Tazio , Kopf Manfred
Published: February 2004

Cytotoxic T lymphocytes (CTL) are essential for control of primary infections by many pathogens and in particular by non‐cytopathic viruses. It has been proposed that long‐term maintenance of CTL memory and control of lymphocytic choriomeningitis virus (LCMV) is dependent upon the presence of T helper cells and interaction of antigen‐presenting cells and CTL via CD40 and its ligand CD40L. However, we demonstrate here that CD40‐CD40L interaction maintains CTL memory by induction of virus‐specific antibodies. In fact, loss of CTL memory responses and spread of virus in mice lacking CD40 or its ligand is prevented by repetitive therapeutic injections of LCMV‐specific antibodies. This indicates that antibodies are essential for long‐term control of non‐cytopathic virus and to maintain protective memory. Transfer of neutralizing antibodies or induction of antibodies by therapeutic vaccination within weeks after infection may therefore prove beneficial for the treatment of chronic virus infections such as HIV, hepatitis B, and hepatitis C.

See accompanying article http://dx.doi.org/10.1002/eji.200324844
The Use of N‐Boc‐1,3‐Oxazolidines as Chiral Auxiliaries in Asymmetric Synthesis
Authors: Agami Claude , Couty François
Published: February 2004

This microreview presents the use of 1,3‐oxazolidines, prepared from enantiomerically pure β‐amino alcohols, as chiral inductors for the stereoselective transformation of adjacent prostereogenic C=C or C=O bonds. After a brief chronological presentation of the major advances in this field, a convenient synthesis of N‐Boc‐2‐acyl‐ and ‐2‐alkenyloxazolidines is presented, together with the use of these heterocycles in asymmetric synthesis. The important role played by the Boc group on the nitrogen of the heterocycle in these transformations is emphasized. In addition to its well known properties as a protecting group, this carbamate actively contributes to the efficiency of this chemistry. Thanks to its bulkiness and chelating properties, it contributes to an efficient stereodifferentiation of the close prostereogenic moiety, but can also directly react with this moiety either as an electrophile or as a nucleophile. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Selenobenzophenones and Diazoalkanes: Isolation of Tetraarylethylenes by the Reaction of Benzophenone Hydrazones with Diselenium Dibromide
Authors: Okuma Kentaro , Kojima Kazuki , Oyama Kosuke , Kubo Kento , Shioji Kosei
Published: February 2004

The reaction of selenobenzophenones with diazomethane afforded the corresponding diarylethylenes and symmetrical olefins. The reaction with diaryldiazomethanes gave three different types of tetraarylethylenes. This reaction proceeded through 1,3,4‐selenadiazoline intermediates, and retrocyclization was observed. The formation of 1,3,4‐selendiazolines was independently confirmed by the reaction of benzophenone hydrazones with diselenium dibromide, which afforded tetraarylethylenes in good yields. This method is applicable to the two‐step synthesis of tetraarylethylenes from benzophenones. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A New Class of Enehydroxylamino Ketones − (R)‐2‐(1‐Hydroxy‐4,4,5,5‐tetraalkylimidazolidin‐2‐ylidene)ethanones: Synthesis and Reactions
Authors: Reznikov Vladimir A. , Roshchupkina Galina I. , Mazhukin Dmitrii G. , Petrov Pavel A. , Popov Sergei A. , Fokin Sergey V. , Romanenko Galina V. , Rybalova Tatjana V. , Gatilov Yuri V. , Shvedenkov Yuri G. , Irtegova Irina G. , Shundrin Leonid A. , Ovcharenko Victor I.
Published: February 2004

Three approaches to the synthesis of (R)‐2‐(1‐hydroxy‐4,4,5,5‐tetraalkylimidazolidin‐2‐ylidene)ethanones 1 are described: (a) condensation of 1,2‐bishydroxylamines with β‐ketoaldehyde synthons, (b) treatment of metallated 1‐hydroxy‐2‐methyl‐4,5‐dihydroimidazoles with esters, and (c) 1,3‐dipolar cycloaddition between 1‐hydroxy‐4,5‐dihydroimidazole‐3‐oxide and DMAD. The reactivity of 1 with electrophiles has been studied. The exocyclic methylene (enamine) carbon atom is shown to be the major site of electrophilic attack. Synthesized chloro‐substituted 1‐hydroxy‐2‐acetylideneimidazolidines react with sodium cyanide to form the corresponding nitriles. Oxidation of these nitriles occurs with formation of persistent vinyl nitroxides, which are of interest as potential paramagnetic ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
An Experimental and Mechanistic Investigation of the Complexities Arising During Inhibition of the BriggsRauscher Reaction by Antioxidants
Authors: Cervellati Rinaldo , Höner Kerstin , Furrow Stanley D. , Mazzanti Francesco , Costa Stefano
Published: February 2004

A method to determine the relative antioxidant capacity of radical scavengers based on the inhibition of the oscillations of the BriggsRauscher (BR) oscillating reaction was previously reported. A semiquantitative mechanistic interpretation of the inhibitory effects required two steps to obtain simulated inhibition times in very good agreement with the experimental ones. The first step is inhibitory, involving H‐atom transfer from antioxidant to the HOO. radical; the second step is a first‐order degradation of the antioxidant to unspecified products. Since the degradation may be due to oxidation and/or iodination of the antioxidant, we studied the kinetics of the subsystems IO$\rm{_{3}^{-}}$(H+)+antioxidant and I2(H+)+antioxidant. We used 2,5‐ and 2,6‐dihydroxybenzoic acids, caffeic acid (=3‐(3,4‐dihydroxyphenyl)prop‐2‐enoic acid), ferulic acid (=3‐(4‐hydroxy‐3‐methoxyphenyl)prop‐2‐enoic acid), pyrocatechol (=benzene‐1,2‐diol), and hydroquinone (=benzene‐1,4‐diol) as antioxidants. Spectra in the wavelength range 500–250 nm were repeated at given time intervals to follow the peaks of the iodine and oxidation products, which were mainly quinones. For the iodination of the above diphenols (=benzenediol derivatives) the substitution and/or addition reactions with I2 or HOI were found to be relatively slow compared to oxidation by IO$\rm{_{3}^{-}}$. Approximate rate constants for oxidation were obtained on the basis of a reasonable kinetic model by using a suitable numerical integration program. Although these complexities can arise also in the completely inhibited BR oscillator, we believe that the inhibitory effects are due to the HOO. scavenging action by diphenols or by quinones since HOO. radicals are also potential reducing agents. We propose two steps that could maintain a small reservoir of diphenol, while both quinone and diphenol deplete HOO. radicals. In short, the complexities do not affect the method for monitoring the relative activity of antioxidants based on the BR oscillating reaction. The effects of temperature on the inverse of the oscillatory time in the BR‐uninhibited system, on the inverse of inhibition times, and on the time length of the resumed oscillations for four antioxidants were also investigated. Apparent average activation energies were obtained.
Bauhinoxepins A and B: New Antimycobacterial Dibenzo[b,f]oxepins from Bauhinia saccocalyx
Authors: Kittakoop Prasat , Nopichai Sombat , Thongon Nuntawan , Charoenchai Panarat , Thebtaranonth Yodhathai
Published: February 2004

Two new antimycobacterial dibenzo[b,f]oxepins, bauhinoxepins A (=3,3,5‐trimethylbenzo[b]pyrano[g][1]benzoxepin‐6,11‐diol; 1) and B (=6‐methoxy‐7‐methyl‐2‐(3‐methylbut‐2‐enyl)dibenzo[b,f]oxepine‐1,8‐diol; 2), were isolated from the roots of Bauhinia saccocalyx, and their structures were elucidated by analysis of spectroscopic data. Bauhinoxepins A and B exhibited antimycobacterial activities with respective minimum‐inhibitory concentrations (MIC) of 6.25 and 12.5 μg/ml. They were inactive (at 20 μg/ml) against the malarial parasite, and also inactive (at 20 μg/ml) towards the Vero, KB, and BC cell lines.
Community health, community involvement, and community empowerment: Too much to expect?
Authors: Baillie Lynne , Broughton Sandra , Bassett‐Smith Joan , Aasen Wendy , Oostindie Madeleine , Marino Betty Anne , Hewitt Ken
Published: February 2004

The Primary Prevention of Cancer Program at the British Columbia Cancer Agency Centre for the Southern Interior (BCCA‐CSI), known as the Waddell Project, is now five years old and currently is in partnership with fourteen regional communities. Each of these communities has a range of community‐developed programs currently in place. The driving force behind the Waddell Project comes from the belief that emancipatory change is central to community health. That is, only those communities that are capable of challenging, questioning, and creating change can make the cancer‐prevention decisions that are relevant, useful, and sustainable within the context of the daily lives of their members. The resulting model for the project was influenced by Habermas's Theory of Communicative Action, from which are derived the project's guiding concepts of equality, negotiated content, collaborative process, inclusion of critique, importance of action, and mutual accountability. In this article, these concepts are revisited from the unique contexts and perspectives of the collaborating participants. Implications would suggest that the processes adopted to support empowered community engagement in cancer prevention are, in many ways, more beneficial than the implementation of the resulting initiative itself. Furthermore, it would seem that, rather than funding, it is prolonged and supportive commitment that is the most crucial factor for facilitating emancipatory change in community health. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 217–228, 2004.
Empowerment and public policy: An exploration of the implications of Section 115 of the Personal Responsibility and Work Opportunity Act
Authors: Kubiak Sheryl Pimlott , Siefert Kristine , Boyd Carol J.
Published: February 2004

The ability of individuals to gain mastery over their environment is considered empowerment. However, empowerment often is assessed without attention to the historical, social, or political context the individual is embedded within. This context often is contingent upon social policies that enhance or limit the choices an individual has to behave in ways constructed as efficacious. One example of such a policy is Section 115 of the Personal Responsibility and Work Opportunity Act of 1996, which mandated a lifetime ban on welfare benefits to individuals convicted of a drug‐related felony. This study examines the policy's implications from the perspective of empowerment. Specifically, we explore the characteristics of those targeted by the policy and what the denial of welfare benefits is likely to mean for this group. Using the sequential application of case study and survey methods, we first reviewed 250 court files of female drug offenders in one midwestern county, finding that most who were convicted of a drug felony received sentences of community probation, predominantly for use and possession. Second, we conducted face‐to‐face interviews with a subsample of 52 drug‐convicted women who otherwise were eligible for welfare benefits and compared them with the general welfare‐to‐work population. The women in our sample had more severe barriers to self‐sufficiency, including less education, higher rates of domestic violence, higher likelihood of recent major depression, and substantially higher rates of post‐traumatic stress disorder. Our findings suggest that the current national policy of denying welfare benefits based on a felony conviction status is unlikely to deter drug use or promote self‐efficacy unless accompanied by effective mental‐health services, help with employment, and supports to ensure a safe living environment. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 127–143, 2004.
Numerical effects in the simulation of Ginzburg–Landau models for superconductivity
Authors: Richardson Walter B. , Pardhanani Anand L. , Carey Graham F. , Ardelea Alexandre
Published: February 2004

Inadequate spatial mesh resolution for simulation of the time‐dependent Ginzburg–Landau equations is shown to give rise to spurious solutions. Phenomenological studies to examine the effect of the physical parameters and boundary conditions in 2D and 3D are presented to illustrate the solution structure and to highlight non‐linear effects related to evolving vortex patterns. We illustrate and explore this issue further by considering a related simplified model in which the number of vortices is equal to the ‘winding number’ that is associated with the applied boundary conditions. Using this model we demonstrate that the solution structure is non‐unique for several values of winding number. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and properties of novel sulfonated polyimides from 2,2′‐bis(4‐aminophenoxy)biphenyl‐5,5′‐disulfonic acid
Authors: Guo Xiaoxia , Fang Jianhua , Tanaka Kazuhiro , Kita Hidetoshi , Okamoto Ken‐ichi
Published: February 2004

Novel sulfonated polyimides (SPIs) were prepared from 1,4,5,8‐naphthalenetetracarboxylic dianhydride (NTDA), 2,2′‐bis(4‐aminophenoxy)biphenyl‐5,5′‐disulfonic acid (oBAPBDS) with nonlinear configuration, and common nonsulfonated diamines. Water uptake (WU) in liquid and vapor, water stability, and proton conductivity σ of the resulting SPI membranes were investigated. They were soluble in m‐cresol and dimethylsulfoxide, and their WUs in liquid were much larger than those of the SPIs from other sulfonated diamines with linear configuration such as 4,4′‐bis(4‐aminophenoxy)biphenyl‐3,3′‐disulfonic acid (BAPBDS). NTDA‐oBAPBDS membrane was soluble in water at room temperature, whereas all the oBAPBDS‐based copolyimide membranes were insoluble in water and maintained mechanical strength after being soaked in distilled water at 80 °C for 40–1000 h. This much improved water stability was due to the enhanced solubility stability of membrane toward water. The water vapor sorption isotherms were rather similar between the SPIs with the nonlinear and linear configurations of sulfonated diamine moieties. The present SPIs with IECs of 1.8–2.6 meq/g, including NTDA‐BAPBDS, showed reasonably high proton conductivities under the highly humid conditions and roughly fell on the same σ–WU relation line. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1432–1440, 2004
Facile synthetic route to polymerizable hindered amine light stabilizers for transition‐metal‐catalyzed olefin copolymerization
Authors: Auer M. , Nicolas R. , Vesterinen A. , Luttikhedde H. , Wilén C.‐E.
Published: February 2004

This work describes a facile method by which a polymerizable hindered amine light stabilizer, 4‐(10‐undecylidene)‐2,2,6,6‐tetramethylpiperidine, was prepared in a single‐step procedure by means of a Wittig reaction. The monomer was successfully copolymerized with ethylene with a rac‐[dimethylsilylenebis(4,5,6,7‐tetrahydro‐1‐indenyl)]zirconium dichloride/methylalumoxane catalyst system. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1350–1355, 2004
Influence of interfaces on the rates of crosslinking in poly(dimethyl siloxane) coatings
Authors: Simpson T. R. E. , Tabatabaian Z. , Jeynes C. , Parbhoo B. , Keddie J. L.
Published: February 2004

We have determined with infrared spectroscopic ellipsometry how the nature of the interface between a thin poly(dimethyl siloxane) (PDMS) coating and its substrate affects the rate of PDMS crosslinking reactions. Reactions between vinyl (CHCH2) end groups on PDMS and silyl (SiH) groups in a crosslinker (hydrosilylation) and between SiH groups and silanol (SiOH) groups, during the so‐called postcure crosslinking stage, have been probed in situ. The overall consumption of SiH follows first‐order reaction kinetics. The first‐order reaction coefficient (k1) for the hydrosilylation crosslinking reaction is the same for coatings on three different substrates: native oxide on silicon (SiO2/Si), polystyrene (PS), and poly(ethylene terephthalate). For the slower postcure reactions, however, the rate of SiH consumption depends on the substrate. In 2.5‐μm PDMS coatings on PS, k1 is about seven times greater than k1 in the same coating on SiO2/Si. In PDMS coatings on a PDMS substrate, when the effect of the interface is thus minimal, k1 is 16 times higher than on SiO2/Si. The dependence of k1 on the type of interface is probably the result of the interfacial segregation and complexation of the Pt catalyst for the postcure reactions. We propose that polar surfaces more strongly attract Pt and form complexes that inhibit the postcure reactions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1421–1431, 2004
Anomalous penetrant diffusion as a probe of the local structure in a blend of poly(ethylene oxide) and poly(methyl methacrylate)
Authors: Cao Haihui , Lin Guoxing , Jones Alan A.
Published: February 2004

Pulse field gradient (PFG) NMR measurements have been made to study the diffusion of diethyl ether in blends of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA). The blends have 10–30 wt % PEO, a composition range within which these materials are amorphous glasses. The diffusion of diethyl ether through the blends is quite rapid, with diffusion constants in the range of 10−7to 10−8cm2/s. In PFG NMR experiments, the apparent diffusion constant depends on the timescale over which diffusion is observed. The values decrease to a plateau as the time increases, this being the signature of tortuous diffusion. Tortuous diffusion is usually observed in heterogeneous systems in which there are regions that support fast diffusion and regions that support slow diffusion or act as barriers. In these blends, PEO is known to undergo rapid segmental motion typical of a rubbery state well below the glass transition, whereas the segmental motion of PMMA is slower by many orders of magnitude. Mobile PEO provides a pathway for the diffusion of structurally similar diethyl ether, whereas solid‐like PMMA acts as a barrier. The size of the domains can be estimated either from a lattice model or from equations for tortuous diffusion. Micrometer sizes are indicated that are unexpectedly large, given the size of the polymer chains and the size of the concentration fluctuations, both of which are thought to be in the tens of nanometers. The lattice model and the equations for tortuous diffusion assume a random dispersion of impenetrable or less penetrable objects. This may not be the appropriate morphology for the diffusion pathway. Recently, large sizes have been indicated by PFG NMR experiments, in which a penetrant is thought to diffuse in a curvilinear fashion. In these blends, the pathway for diethyl ether is along the PEO backbone. A plot of the logarithm of the mean‐square displacement versus the logarithm of time has a slope of about 0.6, close to the value of 0.5 for pure curvilinear diffusion. Exponents with values in this range can also be associated with diffusion in a fractal space, which, in this situation, still consists of mobile PEO. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1053–1067, 2004
Properties of antimicrobial plastics containing traditional food preservatives
Authors: Vartiainen Jari , Skytta Eija , Enqvist Jouni , Ahvenainen Raija
Published: February 2004

Traditional food preservatives, sodium benzoate, sodium nitrite, potassium sorbate and sodium lactate, were incorporated into synthetic plastics, low‐density polyethylene (LDPE), poly(maleic acid‐co‐olefine), polystyrene (PS) and polyethylene terephthalate (PET), aimed at producing antimicrobial packaging material for foodstuffs. The study was undertaken on plaques (thickness 2 mm) and films (thickness 70–120 µm), whose antimicrobial test results clearly differed. Plaques containing 15% sodium nitrite inhibited both Aspergillus niger and Bacillus subtilis, whereas the same concentration of sodium benzoate and potassium sorbate had activity only against B. subtilis. Sodium lactate‐containing samples did not have any antimicrobial activity and none of the samples inhibited Escherichia coli. Antimicrobial substances added into PS and PET produced the strongest activities; however, due to the brittle structure of these materials, they were not tested further. Thus, more thorough tests for antimicrobial activity, migration and oxygen and water vapour permeability were carried out using LDPE films with 2.5–15% sodium benzoate and sodium nitrite. The effects of both substances on permeability properties were negligible. Although the total migration into food simulants measured from the films in many cases exceeded the limit value of 10 mg/dm2, no antimicrobial activity was observed. Copyright © 2003 John Wiley & Sons, Ltd.
Neuromuscular quadriceps dysfunction prior to osteoarthritis of the knee
Authors: Becker Roland , Berth Alexander , Nehring Markus , Awiszus Friedemann
Published: February 2004

Decreased maximal quadriceps strength and voluntary activation has been observed in patients with osteoarthritis in previous studies, but those results do not allow any conclusions to be drawn as to whether quadriceps dysfunction precedes or follows osteoarthritis. Thirty‐two patients (group a) who underwent partial meniscectomy 48 ± 9 month prior to the study were matched according to their weight and body mass index with a control group (group b). The twitch interpolation technique was used to determine maximal voluntary contraction (MVC) and voluntary activation (VA) of the quadriceps muscle of both legs. Subjective assessment of the knee was performed using the Lysholm‐Score. AP and lateral X‐rays of the operated knee were obtained. None of the participants showed any evidence of characteristic radiological or clinical signs for osteoarthritis. A significantly lower MVC was noticed in both the affected and the contralateral knee of group a in comparison to group b (p < 0.01). The VA in group a yielded 80.9 ± 15.4% for the injured side and 83.1 ± 11.5% for the contralateral side, with no statistical difference (p = 0.18). The VA in group b was 89.4 ± 5.8% for the right side and 88 ± 6.8% for the left side both being significantly higher in comparison to group a.

This study has shown, that patients following meniscus resection present with bilateral quadriceps weakness as already described in patients with manifest osteoarthritis. The authors hypothesise that muscle dysfunction may be an etiologic factor underlying the pathologic changes of osteoarthritis. Whether muscle dysfunction occurs also at other sites, e.g. in the upper extremity, remains unclear but would be of interest in order to detect a generalized neuromuscular dysfunction. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Social Networks and Homelessness Among Women Heads of Household
Authors: Toohey Siobhan M. , Shinn Marybeth , Weitzman Beth C.
Published: February 2004

To examine possible bidirectional relationships between homelessness and deficient social networks, we compared the networks of 251 mothers before, and approximately 5 years after, their families entered shelters with networks of 291 consistently housed poor mothers. At Time 1, more women on the verge of homelessness than housed women reported that they had mothers, grandmothers, friends, and relatives but fewer believed these network members were housing resources. At Time 2, after homeless women were rehoused, these network differences between consistently housed and formerly homeless women had largely disappeared. Contrary to prior research findings, formerly homeless mothers did not report smaller networks, more children or fewer partners. However, formerly homeless women did report fewer positive functions. Because of city policies, homeless mothers were frequently rehoused far from network members.
Asking, Witnessing, Interpreting, Knowing: Conducting Qualitative Research in Community Psychology
Authors: Stein Catherine H. , Mankowski Eric S.
Published: February 2004

We present a framework to describe the process of conducting community‐based qualitative research. Qualitative research activities are presented as a series of interrelated acts called asking, witnessing, interpreting, and knowing. Each act in the research process is described in terms of current qualitative research practices, and illustrated with examples from our own research projects on families with schizophrenia and men's mutual support and batterer intervention groups. We critically examine the assumption that qualitative research serves to reveal or amplify the voices of participants. We examine connections between qualitative research and social change and describe the use of qualitative research to not only empower marginalized groups, but also to critique and transform privileged groups. The framework is intended to help community researchers to more fully conceptualize, understand, and engage in the practice of qualitative research.
Adolescent Coping and Neighborhood Violence: Perceptions, Exposure, and Urban Youths' Efforts to Deal with Danger
Authors: Rasmussen Andrew , Aber Mark S. , Bhana Arvinkumar
Published: February 2004

Neighborhood violence is a persistent source of danger, stress, and other adverse outcomes for urban youth. We examined how 140 African American and Latino adolescents coped with neighborhood danger in low, medium, and high crime neighborhoods throughout Chicago. Participants reported using a range of coping strategies (measured via a modified version of the Ways of Coping Scale; R. S. Lazarus & S. Folkman, 1984). In low and medium crime rate areas, using confrontive strategies was significantly correlated with increased exposure to violence, and no strategies were associated with perceptions of safety. Coping strategies were associated with perceived safety to a substantial degree only in high crime neighborhoods, and none were associated with exposure to violence. A k means cluster analysis identified groups that differed in coping profiles and varied in rates of exposure to violence. Moderating effects of gender, ethnicity, and neighborhood were found for both person level and variable level analyses.
Uncertainties in global terrestrial biosphere modeling: 1. A comprehensive sensitivity analysis with a new photosynthesis and energy balance scheme
Authors: Knorr Wolfgang , Heimann Martin
Published: February 2004

Modeling the terrestrial biosphere's carbon exchanges constitutes a key tool for investigation of the global carbon cycle, which has lead to the recent development of numerous terrestrial biosphere models. However, as demonstrated by recent intercomparison studies, results of plant carbon uptake, expressed as net primary productivity (NPP), still diverge to a large degree. Here, we address the question of uncertainty by conducting a series of sensitivity tests with a single, process‐based model, the Biosphere Energy‐Transfer Hydrology (BETHY) scheme. We calculate NPP globally for a standard model setup and various alternative model setups representing either changes in modeling strategy or approximate uncertainties of the most important model parameters. The results show that estimated uncertainties of many process parameters are still too large for reliable predictions of global NPP. The largest uncertainties come from plant respiration, photosynthesis and soil water storage. The surface radiation balance and day‐to‐day variations in weather, often not included into terrestrial vegetation models, are also found to contribute significantly to overall uncertainties, while stomatal behavior, the aerodynamic coupling of vegetation and atmosphere, and the choice of the vegetation map turn out to be relatively unimportant. A further comparison with field measurements of NPP suggests that such data are too unreliable for validating biosphere model predictions. We conclude that the inherent uncertainties in process‐oriented biosphere modeling are able to explain the discrepancies that have occurred when comparing the results of different models.