bluuebunny/crossref_metadata_2025 huggingface dataset:
Teaching of anatomy in a problem‐based curriculum at the Arabian Gulf University: The new face of the museum
Authors: Ganguly Pallab K. , Chakravarty Manoj , Latif Nasir A. , Osman Mirghani , Abu‐Hijleh Marwan
Published: March 2003

The College of Medicine and Medical Sciences of the Arabian Gulf University has an undergraduate medical curriculum that uses problem‐based learning as the principal teaching strategy. Teaching of anatomy comes at various places in the curriculum, and the anatomy museum serves as an important resource and engages the students in self‐directed learning. Although the museum had sufficient resource materials, the emphasis on individualized instruction and self‐directed learning in anatomy has resulted in the need for an effective approach and a reorganization of the facilities in the museum. Thus, we recently rearranged the museum to create 42 modules or stations (learning carrels) focusing on specific organ systems for self‐study by students. Computer‐assisted programs, videocassettes, ultrasound, and structured living anatomy sessions in the clinical professional skills program facilitated such an arrangement. An increased utilization by the students was observed in the reorganized museum. Thus, the museum can play an effective role in the study of anatomy through problem‐based integrated learning modules. Clin. Anat. 16:256–261, 2003. © 2003 Wiley‐Liss, Inc.
Olfactory ensheathing cells transplanted in lesioned spinal cord prevent loss of spinal cord parenchyma and promote functional recovery
Authors: Verdú Enrique , García‐Alías Guillermo , Forés Joaquim , López‐Vales Ruben , Navarro Xavier
Published: March 2003

We studied the effects of olfactory ensheathing cells (OECs) transplanted in a photochemical spinal cord injury in adult rats. After dorsal laminectomy at T8 vertebra, subjacent spinal cord was bathed with rose Bengal for 10 min and illuminated with visible light by means of an optic fiber connected to a halogen lamp for 2.5 min at maximal intensity of 8 kLux. Eight injured rats received a suspension of OECs in DMEM, and another eight rats received DMEM alone. Locomotor ability scored by the BBB scale, pain sensibility by the plantar algesimetry test, and motor‐ and somatosensory‐evoked potentials by electrophysiological techniques were evaluated for 3 months postsurgery. Finally, all rats were perfused with paraformaldehyde and transverse sections from the spinal cord segment at the lesion site were immunostained against GFAP. Area of the preserved spinal cord parenchyma was measured from the GFAP‐immunolabeled cord sections. The BBB score and the amplitude of motor‐ and somatosensory‐evoked potentials were higher in OECs‐transplanted rats than in DMEM‐injected animals throughout follow‐up, whereas the withdrawal response to heat noxious stimulus was lower in OEC‐ than in DMEM‐injected rats. The area of preserved spinal cord was significantly larger in OECs‐transplanted rats than in DMEM‐injected animals. These results indicate that OECs promote functional and morphological preservation of the spinal cord after photochemical injury. GLIA 42:275–286, 2003. © 2003 Wiley‐Liss, Inc.
Alumina slurry formulation intender for spray‐dried powder production
Authors: Filiatre C , Bertrand G , Coddet C , Foissy A
Published: March 2003

Ceramic powders are used to produce coatings using plasma spray processes. The powder granules are required to have a spherical shape, a mean diameter around 40 µm and, moreover, different densities of the powder must be possible. Alumina powders are obtained by spray drying of concentrated aqueous suspensions of particles (slurries). The suspension must contain high solids loading, be stable during the process and have a relatively low viscosity. The aim of this study was to determine how the properties of aqueous alumina slurries influence the characteristics of granules produced by spray drying. The effects of pH and additives (dispersant and binder) on settling and rheological properties of the alumina slurries were investigated. The curves recorded followed the Casson model in the observed range of shear rate. The Casson yield stress values, τc, and the viscosity values, η were determined and used to evaluate particles interaction in the slurries. The dependence of the yield stress and viscosity was measured as a function of polyacrylate dispersant and binder concentration at pH 4 and 9. The corresponding powders have been characterized on a morphological basis.

© 2003 Society of Chemical Industry
Surface charge, effective charge and dispersion/aggregation properties of nanoparticles
Authors: Pochard Isabelle , Boisvert Jean‐Philippe , Persello Jacques , Foissy Alain
Published: March 2003

A careful investigation of the relationship between surface properties and colloidal behaviour of nanometric particles in concentrated media has shed some light on the important parameters that must be controlled in order to improve the dispersion of mineral particles. Experimental methods such as rheology and osmometry reveal that the aggregation/dispersion process is not only a matter of electrostatics as stated by classical theories. In practice, the relationship between the surface charge and the state of dispersion is probably much less straightforward than generally assumed by the classical argument stating that the higher the surface charge, the higher the electrostatic repulsion between particles and the more dispersed the particles. Our results on model hematite and industrial TiO2 systems suggest that the state of dispersion is not always correlated to the magnitude of the surface charge, but seems to depend on the surface density of condensed monovalent counter‐ions. Accordingly, it is believed that the monovalent species present at the interface of mineral particles are deeply involved in the dispersion process of highly concentrated slurries. Much attention should be addressed to the presence of condensed species onto the surface and to their influence on the structure at the interface, in order to prepare better formulations involving (hydr)oxide particles in aqueous media.

© 2003 Society of Chemical Industry
Energetic yields in apatitic calcium phosphate compression: influence of the Ca/P molar ratio
Authors: Pontier Catherine , Viana Marylène , Champion Eric , Bernache‐Assollant Didier , Chulia Dominique
Published: March 2003

The chemical nature of tricalcium phosphate used as compression excipient is not well defined. It can vary between β‐tricalcium phosphate (Ca/P molar ratio = 1.50) and hydroxyapatite (Ca/P molar ratio = 1.67). The present study deals with the compression properties of calcium phosphates with different Ca/P molar ratios (1.50, 1.63 and 1.67) and two trading excipients elaborated by different manufacturing processes: TRI‐TAB® (granulated powder) and TRI‐CAFOS S® (spray‐dried powder). The compression properties are analyzed in terms of energetic compression yields deduced from the compression and rupture cycles. The results show that the proportions of friction and elasticity during apatitic calcium phosphate compression are the same, whatever the chemical nature and the manufacturing process of the material. The only property that differs greatly is the conversion of the energy into cohesion. In comparison with trading excipients, the synthesized apatitic calcium phosphate materials exhibit higher cohesion properties: the product with a Ca/P molar ratio of 1.63 is the most cohesive, the apatitic tricalcium phosphate converts to a smaller extent the compression energy into cohesion, whereas hydroxyapatite displays a similar compression ability as TRI‐TAB and TRI‐CAFOS S. This study shows the importance of the chemical nature on the compression properties of apatitic calcium phosphates, and the need to rationalize the physical grade as well as the chemistry of the commercialized materials. The elaboration process does not seem to influence the efficiency of the cohesion acquisition, but affects the flowability.

© 2003 Society of Chemical Industry
Encapsulation of an organic phthalocyanine blue pigment into polystyrene latex particles using a miniemulsion polymerization process
Authors: Lelu S , Novat C , Graillat C , Guyot A , Bourgeat‐Lami E
Published: March 2003

Aqueous dispersions of polystyrene latexes encapsulating a copper phthalocyanine blue pigment were formulated using the miniemulsion polymerization technique. The organic pigment was first suspended into the monomer phase, and the resulting oily suspension was subsequently converted into stable miniemulsion droplets using various types and concentrations of hydrophobe (costabilizer). The pigmented monomer emulsions were finally polymerized using potassium persulfate as the initiator. It was shown that the organic pigment could stabilize the miniemulsion droplets, and be thus satisfactorily encapsulated without introducing any other compound in the formulation. In a subsequent approach, the stability of the miniemulsion droplets was improved by using either hexadecane, hexadecanol or a polystyrene prepolymer as the hydrophobe. Dynamic light scattering and transmission electron microscopy measurements showed that the size and the morphology of the resulting pigmented polymer particles were greatly influenced by the presence of the costabilizer.

© 2003 Society of Chemical Industry
Hysteresis behaviour in temperature‐induced emulsion inversion
Authors: Márquez Laura , Graciaa Alain , Lachaise Jean , Salager Jean‐Louis , Zambrano Noelia
Published: March 2003

Emulsion inversion produced by a change in temperature usually takes place reversibly, ie at the same temperature whatever the direction of change. The present study indicates previously unreported hysteresis in a transitional inversion driven by a temperature variation in a non‐ionic system containing Tween surfactant mixtures. In both directions of the temperature variation, a delay is exhibited with respect to the standard phase inversion temperature of the equilibrated system. The width of the hysteresis region depends on the rate of temperature change. This behaviour, which does not happen in the presence of alcohol, is attributed to the presence of liquid crystals.

© 2003 Society of Chemical Industry
A rheological study of associating polymer–particle interactions in tricalcium silicate pastes
Authors: Rastoul Katy , Van Damme Henri , Lafuma Françoise , Lequeux François , Colombet Pierre , Mansoutre Sandrine , Pasquier Michel
Published: March 2003

Cement pastes are used in various conditions of fluidity. This leads to the necessary introduction of polymers in order to control the rheology and to stabilize the slurry against segregation. This work describes the influence of hydrophobically modified acrylate polyelectrolytes on the rheological behavior of a tricalcium silicate paste at a constant solid volume ratio Φ = 0.32.

© 2003 Society of Chemical Industry
A novel criterion for studying the phase equilibria of non‐ionic surfactant–triglyceride oil–water systems
Authors: Van Hecke Elisabeth , Catté Marianne , Poprawski Jérôme , Aubry Jean‐Marie , Salager Jean‐Louis
Published: March 2003

The formulation of macro‐ and microemulsions through the Hydrophilic Lipophilic Deviation (HLD) concept based on phase behaviour observations, has mostly been applied to mineral oils. The present research reports a similar approach using triglyceride‐based oils (seven vegetable oils and one pure triglyceride) and ethoxylated (nonylphenol and isotridecanol) surfactant systems. Formulation scans are carried out by varying the surfactant average degree of ethoxylation, eg the ethylene oxide number (EON), at 50 °C, 55 °C and 60 °C. Because these systems do not exhibit a Winsor III phase behaviour, the so‐called optimum formulation was detected for EON0.5, ie the EON value at which the surfactant partitions equally into the aqueous and the oil phases, which was found to coincide with the minimum stability of the emulsified systems. Experimental EON0.5 values ranged from 3.5 to 5.5 as temperature, oil nature and surfactant were altered.

© 2003 Society of Chemical Industry
Novel bolaamphiphiles with saccharidic polar headgroups: synthesis and supramolecular self‐assemblies
Authors: Benvegnu T , Lecollinet G , Guilbot J , Roussel M , Brard M , Plusquellec D
Published: March 2003

Two series of novel sugar‐based bolaamphiphiles characterized by a tetraether‐type aliphatic linker or a linker composed of a single polymethylene chain were synthesized. Evaluation of their self‐assembling properties was performed using optical microscopy, freeze fracture electron microscopy and dynamic light scattering. Unsymmetrical phosphate derivatives spontaneously formed thermostable monolayered vesicles, whereas neutral glycolipids including a cyclopentane ring in the middle of the bridging chain, exhibited unusual two by two monolayer associations. Bipolar surfactants possessing a single polymethylene bridging chain were found to self‐organize into bilayered or monolayered vesicles, disks or fibres depending on the symmetrical or unsymmetrical structure of the lipids, the bridging chain length, the nature of the polar groups and also the structure of the spacers.

© 2003 Society of Chemical Industry
Formulation of aqueous concentrated alumina suspensions. Influence of a disaccharide: trehalose
Authors: Pagnoux Cécile , Poeydemenge Frédéric , Baumard Jean‐François
Published: March 2003

Trehalose, a disaccharide, is very well known to protect living cells efficiently from dehydration and has been tested in the formulation of aqueous alumina suspensions. It has been added into slurries stabilized with Tiron®, (HO)2C6H2(SO3Na)2, which permits a high state of dispersion by creating repulsive potential between particles. Trehalose added into such suspensions acts as a lubricant and enhances flowing properties of suspensions because of its strong interaction with water which breaks the hydrogen‐bonded network of the solvent. Trehalose addition is beneficial for carrying out shaping methods of alumina components by coagulation as it increases solid concentration in the suspension, which facilitates pouring the suspension into a mould. Unfortunately this addition hinders coagulation of particles.

© 2003 Society of Chemical Industry
Contribution of chitin derivatives to the modification of physicochemical properties of formulations
Authors: Desbrières J
Published: March 2003

Chitin was modified to obtain controlled amphiphilic polysaccharides which may be either cationic (chitosan) or anionic (carboxymethylchitin). The hydrophile–lipophile balance (HLB, also called hydrophilic–hydrophobic balance) was modified with respect to different parameters (pH, degrees of substitution of ionic or alkyl groups) and the rheological and tensioactive properties of formulations based on these polymers have been studied. The presence of hydrophobic groups and interactions among themselves allow these polymers to act as thickening or gelling agents with an improved temperature stability. The surface activity of anionic carboxymethylchitins can be improved either by the addition of a cationic surfactant which plays the role of counterion by electrostatic interaction (forming a surfactant–polyelectrolyte complex, SPEC) or by N‐alkylation. The SPECs are found to be more efficient than alkyl derivatives because the necessary surfactant concentration to reach tensioactive properties is much lower than its critical micellar concentration in the pure solution.

© 2003 Society of Chemical Industry
Solubilization in some anionic/cationic surfactant binary systems
Authors: Cui Zhenggang , Canselier Jean Paul
Published: March 2003

The solubilization behaviour of n‐heptane, toluene and octan‐1‐ol in anionic/cationic surfactant binary mixtures was studied. Triethanolammonium dodecylpolyoxyethylene sulfate (TADPS, containing ca 2 ethylene oxide units) was mixed with hexadecyltrimethylammonium bromide (CTABr), dodecylpyridinium chloride (DPCl) or hexadecylpyridinium chloride (CPCl). The synergism for solubilization in those mixtures depended on the polarity of the solubilizate, involving its location in micelles. For n‐heptane (non‐polar), a practically positive synergistic effect was observed and the maximum additive concentration (MAC) in the TADPS/CTABr system was well predicted by Nishikido's ideal model. For toluene (slightly polarizable), solubilized both in the core and palisade layer of the micelle, a practically positive synergism was noticed. For octan‐1‐ol (amphipathic) usually solubilized in the palisade layer or forming mixed micelles with surfactants, however, a negative synergistic effect was observed and the partition coefficient between micellar and aqueous phases in the TADPS/CTABr system was well predicted by Treiner's non‐ideal model. Copyright © 2003 Society of Chemical Industry
A simple automated method of quantitative characterization of foam behaviour
Authors: Lunkenheimer Klaus , Malysa Kazimierz
Published: March 2003

There are various methods available to measure foam stability. However, their main drawback is that their results are hardly comparable because definite boundary conditions are missing. One particular disadvantage is that there is no method which is applicable to systems of very low (transient or ‘wet’ foams) as well as of very high (metastable or ‘dry’ foams) foam stability. Here, we put forward a novel automatic, pneumatic method that is applicable to both systems. Its principle relies on the measurement of the foam produced by dispersing a definite amount of gas in a definite volume of solution at constant gas velocity. Foam and draining solution are determined simultaneously. This method has advantages over all other methods in several respects such as: (1) it represents a simple and definite procedure under well‐defined boundary conditions, (2) it is generally applicable to all kinds of foam, and (3) it provides new standard parameters for the quantitative characterization of foamability and foam stability. The standard parameters can be related to the basic adsorption properties and the structure of the surfactant. The method's capability is demonstrated with three different non‐ionic and ionic surfactants belonging to the wet (n‐octanoic acid) and dry foam systems (n‐nonyl‐α‐D‐glucopyranoside and sodium dodecylsulfate). Copyright © 2003 Society of Chemical Industry
The emergence of formulation engineering in emulsion making—transferring know‐how from research laboratory to plant
Authors: Salager Jean L , Antón Raquel E , Briceño María I , Choplin Lionel , Márquez Laura , Pizzino Aldo , Rodriguez María P
Published: March 2003

All variables capable of altering the physico‐chemical formulation, including temperature, are included in a generalized concept known as the hydrophilic–lipophilic deviation (HLD), which measures the departure from the reference state at which the surfactant–oil–water system exhibits Winsor III three‐phase behaviour. The general phenomenology representing the emulsion properties (type, stability, viscosity, drop size) can be qualitatively charted in a three‐dimensional map, where each region exhibits definite features. Travelling across the map from one region to another corresponds to modifications in formulation, composition and stirring along a path which can describe the protocol of change in an industrial process dealing with emulsion making, inversion or reworking. Six different path cases, labelled as unit operations, emerge from a systematic categorizing, and allow the interpretation of complex industrial processes such as crude oil dehydration, or the manufacturing of paint, cosmetics or heavy hydrocarbon emulsions.

© 2003 Society of Chemical Industry
Micro‐encapsulation by complex coacervation: influence of surfactant
Authors: Mayya K S , Bhattacharyya A , Argillier J‐F
Published: March 2003

Paraffin oil has been encapsulated using complex coacervation of gelatin and Arabic gum in the presence of a surfactant. Addition of an oppositely charged surfactant to a polyelectrolyte markedly increases the yield of the process. We report a two‐layer encapsulation of paraffin oil, based on a primary layer of interface active polyelectrolyte–surfactant complex, followed by a second layer of the conjugate polyelectrolyte–polyelectrolyte complex. Surfactant concentration has been found to be a crucial parameter to obtain good quality microcapsules and optimal yield. This confirms the importance of formulation aspects when looking for optimization of these techniques of micro‐encapsulation.

© 2003 Society of Chemical Industry
Monomolecular condensation of DNA by cationic detergents
Authors: Dauty Emmanuel , Behr Jean‐Paul
Published: March 2003

Controlling the size of condensed DNA particles is a key determinant for their diffusion in vivo as well as for gene delivery to target cells. Towards this goal, DNA molecules were compacted individually by cationic thiol‐detergents into discrete nanometric entities. These particles were then stabilized by air‐induced dimerization of the detergent into a disulfide lipid on the template DNA. Using a tetradecane–cysteine–ornithine (C14COrn) detergent, a solution of 5.5 Kb plasmid DNA was thus converted into a monodisperse population of 35‐nm particles. The stability of the complexes, as well as their size, morphology and transfection efficiencies were investigated. Surprisingly, the electrophoretic mobility of the quasi‐neutral condensed DNA was found higher than that of the extended DNA polyanion. The diameters of particles resulting from the condensation of DNA of various sizes was measured by dynamic light scattering and found to vary as the cubic root of the DNA size. In an attempt to extend their biodistribution and to target tumour cells, we have prepared folate–poly(ethylene oxide)‐coated particles that were shown to bind to the cell‐surface folate receptor. Copyright © 2003 Society of Chemical Industry
Formulation of solid products: two‐component tablets with a disintegrating agent
Authors: Hutin S , Accart P , Oulahna D , Dodds JA
Published: March 2003

The formulation of binary tablets containing an insoluble powder and a disintegrating agent is examined from the point of view of the particle packing theory in terms of the relative size and proportion of the two components. A relationship is found between the overall porosity and the crush resistance, and between the contacts between particles and the disintegration time. Tablets made with an industrial tablet press for three different systems, caffeine–starch, cocoa–ultrafine sugar and cocoa–icing sugar, were tested for crush resistance and disintegration time. The results followed the theoretical predictions. Copyright © 2003 Society of Chemical Industry
Amphiphilic polyelectrolyte for stabilization of multiple emulsions
Authors: Michaut Fanny , Hébraud Pascal , Perrin Patrick
Published: March 2003

Multiple emulsions are complex thermodynamically unstable systems where both types of emulsion coexist. We investigated the stability behaviour of water‐in‐oil‐in‐water (W/O/W) emulsions formulated with a hydrophobically modified poly(sodium acrylate) emulsifier at the outer interface and a monomeric surfactant (span 80) at the inner interface. Their stability was tested through release kinetics of a marker (NaCl) initially encapsulated in the aqueous droplets, and by rheology. Slow release rates and remarkably long shelf‐life were obtained compared to typical multiple emulsions stabilized by two commonly used surfactants (span 80 and tween 20). In addition, we prepared stable highly concentrated multiple emulsions. Their rheological behaviour indicated that the internal interface was essentially covered with span 80. Thus, transportation of the polymer across the oil phase is limited, which in turn explains, at least partially, the stability improvement in the presence of the polymeric emulsifier. Finally, the long lifetime of the emulsions allowed study by diffusing wave spectroscopy of the interactions between the droplets and the globule surface which are important for understanding the destruction mechanisms of multiple emulsions.

© 2003 Society of Chemical Industry
New regioselective synthesis of metalinked aromatic polyketones from metasubstituted bis(arylsilane)s and aromatic dicarboxylic acid chlorides
Authors: Takeuchi Hisashi , Kakimoto Masa‐Aki , Imai Yoshio
Published: March 2003

A new regioselective synthesis of metalinked aromatic polyketones was achieved for the first time. New metaconnected aromatic polyketones with inherent viscosities of up to 0.49 dL/g were regioselectively synthesized by the solution polycondensation of metasubstituted bis(arylsilane)s with aromatic dicarboxylic acid chlorides in the presence of aluminum chloride in 1,2‐dichloroethane along with the elimination of chlorotrimethylsilane. The polycondensation proceeded through aromatic electrophilic ipso‐substitution. The metalinked aromatic polyketones had considerably lower glass‐transition temperatures and 10% weight‐loss temperatures than those of their counterpart paracatenated aromatic polyketones. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1428–1434, 2003
Synthesis and characterization of novel poly(ester‐carbonate)s by copolymerization of trans‐4‐hydroxy‐L‐proline with cyclic carbonate
Authors: Lee Ren‐Shen , Lin Tz‐Feng , Yang Jen‐Ming
Published: March 2003

The melt ring‐opening/condensation reaction of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L‐proline (N‐CBz‐Hpr) with cyclic carbonate [trimethylene carbonate (tri‐MC) or tetramethylene carbonate (tetra‐MC)] at a wide range of molar fractions in the feed produced new degradable poly(ester‐carbonate)s. The influence of reaction conditions such as polymerization time and temperature on the yield and inherent viscosity of the copolymers was investigated. The polymerizations were carried out in bulk at 140 °C with 1.5 wt % stannous octoate as a catalyst for 30 h. The poly(ester‐carbonate)s obtained were characterized by Fourier transform infrared spectroscopy, 1H NMR, differential scanning calorimetry, gel permeation chromatography, and Ubbelohde viscometry. The copolymers synthesized exhibited moderate molecular weights with rather narrow molecular weight distributions. The values of the glass‐transition temperature (Tg) of the copolymers depend on the molar fractions of cyclic carbonate. For the poly(N‐CBz‐Hpr‐co‐tri‐MC) system, with a decreased tri‐MC content from 93 to 16 mol %, the Tg increased from −10 to 60 °C. Similarly, for the poly(N‐CBz‐Hpr‐co‐tetra‐MC) system, when the tetra‐MC content decreased from 80 to 8 mol %, the Tg increased from −18 to 52 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐tri‐MC) Tg and the compositions was in approximation with the Fox equation. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐tri‐MC)s was evaluated from weight‐loss measurements. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1435–1443, 2003
Polymerization of 1,3‐dienes with functional groups. II. Free‐radical polymerization of N‐(2‐methylene‐3‐butenoyl)piperidine
Authors: Yaegashi Takayuki , Takeshita Hiroki , Takenaka Katsuhiko , Shiomi Tomoo
Published: March 2003

The free‐radical homopolymerization and copolymerization behavior of N‐(2‐methylene‐3‐butenoyl)piperidine was investigated. When the monomer was heated in bulk at 60 °C for 25 h without an initiator, about 30% of the monomer was consumed by the thermal polymerization and the Diels–Alder reaction. No such side reaction was observed when the polymerization was carried out in a benzene solution with 1 mol % 2,2′‐azobisisobutylonitrile (AIBN) as an initiator. The polymerization rate equation was found to be Rp ∝ [AIBN]0.507[M]1.04, and the overall activation energy of polymerization was calculated to be 89.5 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4‐structure that included both 1,4‐E and 1,4‐Z configurations. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were carried out in benzene solutions at 60 °C with AIBN as an initiator. In the copolymerization with styrene, the monomer reactivity ratios were r1 = 6.10 and r2 = 0.03, and the Q and e values were calculated to be 10.8 and 0.45, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1545–1552, 2003
Synthesis and characterization of mesogen‐jacketed liquid‐crystal polymers based on 2,5‐bis(4′‐alkoxyphenyl)styrene
Authors: Yu Zhenning , Tu Huilin , Wan Xinhua , Chen Xiaofang , Zhou Qi‐Feng
Published: March 2003

A series of novel mesogen‐jacketed liquid‐crystal polymers, poly[2,5‐bis(4′‐alkoxyphenyl)‐styrene] (P‐n, n = 1–11), were prepared via free‐radical polymerization of newly synthesized monomers, 2,5‐bis(4′‐alkoxyphenyl)styrene (M‐n, n = 1–11). The influence of the alkoxy tail length on the liquid‐crystalline behaviors of the monomers and the polymers was investigated with differential scanning calorimetry (DSC), thermogravimetry, polarized optical microscopy (POM), and wide‐angle X‐ray diffraction (WAXD). The monomers with n = 1–4, 9, and 11 were monotropic nematic liquid crystals. All other monomers exhibited enantiotropic nematic properties. Their melting points (Tm's) decreased first as n increased to 6, after which Tm increased slightly at longer spacer lengths. The isotropic–nematic transition temperatures decreased regularly with increasing n values in an odd–even way. The glass‐transition temperatures (Tg's) of the polymers first decreased as the tail lengths increased and then leveled off when n ≥ 7. All polymers were thermally stable and entered the mesophase at a temperature above Tg. Upon further heating, no mesophase‐to‐isotropic melt transition was observed before the polymers decomposed. WAXD studies indicated that an irreversible order–order transition for the polymers with short tails (n ≤ 5) and a reversible order–order transition for those with elongated tails (n ≥ 6) occurred at a temperature much higher than Tg. However, such a transition could not be identified by POM and could be detected by DSC only on heating scans for the polymers with long tails (n ≥ 7). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1454–1464, 2003
Dimeric liquid‐crystalline epoxyimine monomers: Influence of dipolar moments on mesomorphic behavior and the formation of liquid‐crystalline thermosets
Authors: Ribera David , Serra Angels , Mantecón Ana
Published: March 2003

We examine some of the structural aspects that influence the mesomorphic behavior of liquid‐crystalline dimeric epoxy resins with imine groups in the mesogens. We synthesized two new series of monomers and compared them with previously synthesized monomers. Compared with previously studied series, the imine group in the new monomers is oriented differently with respect to the ether and ester groups linked to the end of the mesogenic unit. Our results confirmed the importance of polarization of the mesogenic groups and the presence of an ester group in the inner position in the formation of smectic mesophases. By curing with primary and tertiary amines, we demonstrate that these two requirements are necessary if liquid‐crystalline thermosets are to be obtained with different degrees of order. These studies were carried out with differential scanning calorimetry, polarized optical microscopy, and X‐ray diffraction. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1465–1477, 2003
Polypropylene fractions produced by binary metallocene catalysts
Authors: Marques Maria de Fátima V. , Chaves Érica Gervasoni
Published: March 2003

Because of the great economic interest in propylene‐based polymers and the possibility of designing materials with desired properties with metallocene catalyst mixtures, we investigated the characteristics of polypropylenes produced by mixtures of SiMe2Ind2ZrCl2: dimethylsilane‐bis(indenyl) zirconocene (1) and Et(Flu)(Cp)ZrCl2: ethylidene (fluorenyl cyclopentadienyl) zirconocene (2) in different proportions. The polymers were fractionated with solvents, and the fractions were characterized. We observed that the polymers produced by the different mixed systems showed lower weight‐average molecular weights and only slightly broader molecular weight distributions than polypropylenes synthesized by the individual catalysts. We concluded that catalyst 1 acted independently of catalyst 2, producing polymers with the same isotacticity. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1478–1485, 2003
Highly stable rigid main‐chain nonlinear optical polymers with nematic phase: Effect of liquid‐crystalline phase on nonlinear optical response
Authors: Sandhya K. Y. , Pillai C. K. S. , Sato Masataka , Tsutsumi Naoto
Published: March 2003

Nonlinear optical (NLO) rigid main‐chain polyesters containing azobenzene mesogens with high thermal and temporal stabilities were synthesized from derivatives of hydroxyphenylazobenzoic acid. The NLO properties of the homopolymer, poly[4‐(4‐hydroxy‐3‐methyl phenyl)azo]benzoic acid, and copolymers of 4‐[(4‐hydroxy‐3‐methylphenyl)azo]benzoic acid, 4‐[(4‐hydroxy‐2‐methylphenyl)azo]benzoic acid, and 4‐[(4‐hydroxy‐2‐pentadecyl phenyl)azo]benzoic acid (PSCpHBA) with p‐HBA were measured by the Maker fringe technique. The thermal and liquid‐crystalline (LC) phase behaviors of the polymers were examined by differential scanning calorimetry, a thermal‐stimulated polarization current, and polarized light microscopy. The polymers except PSCpHBA exhibited nematic‐threaded and Schlieren textures. The LC orientations give rise to an enhanced NLO response. The polymers had high thermal and temporal stabilities for second‐harmonic generation activity because of their rigid aromatic backbone. This study suggests that the rigid aromatic main chain exhibiting an LC phase is a promising simple method to synthesize highly stable NLO polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1527–1535, 2003
New liquid‐crystalline thermosets from liquid‐crystalline bisazomethynic epoxy resins with naphthylene disruptors in the central core
Authors: Castell P. , Serra A. , Galià M.
Published: March 2003

We synthesized novel epoxy‐terminated monomers on the basis of imine groups with spacers of different lengths between mesogens and reactive groups and examined their mesogenic properties. Their reaction with primary aromatic diamines and tertiary amines was carried out to investigate the formation of liquid‐crystalline thermosets. We explored how the curing conditions and the structures of the monomers and amines affected the formation of ordered networks. The special symmetry of a 1,5‐disubstituted naphthalene unit in the central core led to nematic mesophases in the pure liquid‐crystalline epoxy resins, and thermosets with locked nematic textures were obtained in all cases, regardless of the length of the spacer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1536–1544, 2003
Educational achievement, employment and living situation in long‐term young adult survivors of childhood cancer in the Netherlands
Authors: Langeveld N.E. , Ubbink M.C. , Last B.F. , Grootenhuis M.A. , VoÛte P.A. , de Haan R.J.
Published: March 2003

This paper investigated educational achievement, employment status, living situation, marital status and offspring in 500 Dutch long‐term young adults survivors of childhood cancer (age range, 16–49 years, 47% female). The results were compared with a reference group of 1092 persons with no history of cancer (age range, 15–33 years, 55% female). The impact of demographic and medical characteristics on psychosocial adjustment was studied. All participants completed a self–report questionnaire. The results showed that, although many survivors are functioning well and leading normal lives, a subgroup of survivors were less likely to complete high‐school, to attain an advanced graduate degree, to follow normal elementary or secondary school and had to be enrolled more often on learning disabled programs. The percentage of employed survivors was lower than the percentage of employed controls in the comparison group, but more survivors were student or homemaker. Survivors had lower rates of marriage and parenthood, and worried more about their fertility and the risk of their children having cancer. Survivors, especially males, lived more often with their parents. Cranial irradiation dose ≤25 Gy was an important independent prognostic factor of lower educational achievement. Survivors with a history of brain/CNS tumours had a higher risk of being single than survivors with a diagnosis of leukaemia/non‐Hodgkin lymphoma. These results indicate that important aspects of life are affected in a substantial number of persons who have been diagnosed with cancer during childhood or adolescence. Copyright © 2002 John Wiley & Sons, Ltd.
Caregiver and patient marital satisfaction and affect following hematopoietic stem cell transplantation: a prospective, longitudinal investigation
Authors: Langer Shelby , Abrams Janet , Syrjala Karen
Published: March 2003

The process of stem cell transplantation (SCT) is both intra and inter dependent; like patients, spousal caregivers (CGs) are affected by the experience. Few empirical investigations have focused on the needs of CGs or dyadic differences over the course of adaptation—the foci of the present study. SCT recipients and spousal CGs (n=131 dyads) completed the Profile of Mood States (POMS) and the Dyadic Adjustment Scale at three time points: pre‐transplant, 6 months post‐transplant and 1 year post‐transplant. A separate, non‐medical group completed the POMS as a normative sample. CGs reported higher levels of depression and anxiety as compared to patients and non‐medical norms. With respect to marital satisfaction, couples were matched in their perceptions of the relationship prior to transplantation but grew mismatched over time. Six months and 1 year post‐transplant, CGs reported lower levels of marital satisfaction relative to their patient counterparts. Counter to prediction, change in CG marital satisfaction (from pre‐transplant to 1 year post‐transplant) was predicted only by CG gender, not patient physical, nor psychosocial characteristics. Findings offer implications for person‐specific and relationship‐protective interventions. Copyright © 2002 John Wiley & Sons, Ltd.
Induction and characterization of a novel amine oxidase from the yeast Kluyveromyces marxianus
Authors: Corpillo Davide , Valetti Francesca , Giuffrida Maria Gabriella , Conti Amedeo , Rossi Antonello , Finazzi‐Agrò Alessandro , Giunta Carlo
Published: March 2003

An amine oxidase from the yeast Kluyveromyces marxianus was induced, purified and completely characterized; it was shown to belong to the class of copper‐containing amine oxidases (E.C. 1.4.3.6). The enzyme was induced by putrescine and, very strongly, by copper(II); structural–functional characterization of the enzyme was performed, including determination of molecular weight, glycosylation, copper and TPQ content, isoelectric point, KM and kCAT (with benzylamine as substrate), pH, temperature and ionic strength effect on catalysis, substrate and inhibitor specificity. A 700 bp clone was isolated containing the cDNA that encodes for the C‐terminus of the enzyme; the amino acid sequence deduced (the first available for a benzylamine oxidase from yeast) was compared to that of other copper amine oxidases from microorganisms and higher organisms. From the results obtained, the putrescine/benzylamine oxidase from Kluyveromyces marxianus was found to have a good homology with other enzymes of this class from microorganisms, and particularly with AO I from Aspergillus niger. Nonetheless, some features resulted closer to those of animal amine oxidases and histaminases. Some potential biotechnological applications are proposed. The cDNA Accession No. is AJ320485. Copyright © 2003 John Wiley & Sons, Ltd.
The Escherichia coli RecA protein complements recombination defective phenotype of the Saccharomyces cerevisiae rad52 mutant cells
Authors: Dudáš Andrej , Marková Eva , Vlasáková Danuša , Kolman Ada , Bartošová Zdena , Brozmanová Jela , Chovanec Miroslav
Published: March 2003

The Saccharomyces cerevisiae rad52 mutants are sensitive to many DNA damaging agents, mainly to those that induce DNA double‐strand breaks (DSBs). In the yeast, DSBs are repaired primarily by homologous recombination (HR). Since almost all HR events are significantly reduced in the rad52 mutant cells, the Rad52 protein is believed to be a key component of HR in S. cerevisiae. Similarly to the S. cerevisiae Rad52 protein, RecA is the main HR protein in Escherichia coli. To address the question of whether the E. coli RecA protein can rescue HR defective phenotype of the rad52 mutants of S. cerevisiae, the recA gene was introduced into the wild‐type and rad52 mutant cells. Cell survival and DSBs induction and repair were studied in the RecA‐expressing wild‐type and rad52 mutant cells after exposure to ionizing radiation (IR) and methyl methanesulphonate (MMS). Here, we show that expression of the E. coli RecA protein partially complemented sensitivity and fully complemented DSB repair defect of the rad52 mutant cells after exposure to IR and MMS. We suggest that in the absence of Rad52, when all endogenous HR mechanisms are knocked out in S. cerevisiae, the heterologous E. coli RecA protein itself presumably takes over the broken DNA. Copyright © 2003 John Wiley & Sons, Ltd.
trans‐Complementation assay establishes the role of proregion hydrophobic amino acid residues in the biosynthesis of Saccharomyces cerevisiae Kex2p endoprotease
Authors: Lesage Guillaume , Guimond Julie , Boileau Guy
Published: March 2003

The proregion of Saccharomyces cerevisiae endoprotease Kex2p is essential for the biosynthesis of an active enzyme. It has been suggested that the proregion acts in the endoplasmic reticulum to catalyse folding of the enzyme. To identify amino acid residues important for proregion function, we used an in vivo system in which the Kex2p proregion can act in trans to activate a Kex2p enzyme synthesized without its proregion. Activation of Kex2p by wild‐type and mutated proregions revealed the essential role of hydrophobic residues F37, V39 and F70 in enzyme activation. Further exploration of the role of these residues by in vitro inhibition of Kex2p activity by its proregion indicated that they are essential to form the proregion/enzyme bimolecular complex. In contrast, basic residues K108 and R109, located in the C‐terminus of the proregion, are not involved in complex formation but are necessary for the biosynthesis of an active enzyme. Copyright © 2003 John Wiley & Sons, Ltd.
Removal of domain D2 or D3 of the human urokinase receptor does not affect ligand affinity
Authors: Riittinen Leena , Limongi Paola , Crippa Massimo P. , Conese Massimo , Hernandez-Marrero Luciano , Fazioli Francesca , Blasi Francesco
Published: April 2003

The main ligand‐binding determinant of the human urokinase receptor (uPAR) is located in the amino terminal domain D1, but when isolated this domain presents a 1500 fold lower affinity than the intact three‐domain uPAR (D1D2D3) [1]. uPAR mutants missing either domain 2 (D1HD3) or domain 3 (D1D2) were expressed in murine LB6 cells and showed to be properly GPI‐anchored to the cell surface. Binding assays with [125I]ATF demonstrated that these mutants possessed a normal (D1D2) or slightly reduced (D1HD3) affinity, indicating that a high ligand‐affinity may be achieved by a combination of D1 with domain D2 or D3.
Absence of γ‐sarcoglycan (35 DAG) in autosomal recessive muscular dystrophy linked to chromosome 13q12
Authors: Jung Daniel , Leturcq France , Sunada Yoshihide , Duclos Franck , Tomé Fernando M.S. , Moomaw Carolyn , Merlini Luciano , Azibi Kemal , Chaouch Malika , Slaughter Clive , Fardeau Michel , Kaplan Jean-Claude , Campbell Kevin P.
Published: April 2003

We have partially sequenced rabbit skeletal muscle γ‐sarcoglycan an integral component of the dystrophin‐glycoprotein complex. Specific antibodies were produced against a γ‐sarcoglycan peptide and used to examine the expression of γ‐sarcoglycan in skeletal muscle of patients with severe childhood autosomal muscular dystrophy linked to chromosome 13q12 (SCARMD). We show by immunofluorescence and Western blotting that in skeletal muscle from these patients γ‐sarcoglycan is completely absent and α‐ and β‐sarcoglycan are greatly reduced in abundance, whereas other components of the DGC are preserved. In addition, we show that in normal muscle α‐, β‐, and γ‐sarcoglycan constitute a tightly associated sarcolemma complex which can not be disrupted by SDS treatment.
Inactivation of tissue inhibitor of metalloproteinase‐1 by peroxynitrite
Authors: Frears Emma R. , Zhang Zhi , Blake David R. , O'Connell James P. , Winyard Paul G.
Published: April 2003

Peroxynitrate (ONOO−) has recently been implicated in connective tissue destruction in vivo. We have studied the effect of ONOO− on the activity of tissue inhibitor of metalloproteinase‐1 (TIMP‐1) in vitro. The inactivation of TIMP‐1 by ONOO− was dose dependent with 50 μM ONOO− reducing the inhibitory activity of TIMP‐1 towards gelatinase‐A by 50%. High concentrations of ONOO− (500 μM‐5 mM) caused protein fragmentation whilst lower concentrations (<250 μM) inactivated TIMP‐1 without altering the molecular weight. Inactivation could be blocked by ONOO− scavengers but not by hydroxyl radical scavengers. Our results show that ONOO− is capable of inactivating TIMP‐1, a process which could potentiate metalloproteinase‐mediated tissue breakdown.
Novel 28‐kDa secretory protein from rat olfactory epithelium
Authors: Peshenko I.V. , Novoselov V.I. , Evdokimov V.A. , Nikolaev Yu.V. , Shuvaeva T.M. , Lipkin V.M. , Fesenko E.E.
Published: April 2003

We have isolated a novel secretory 28‐kDa protein which is an abundant component of the rat olfactory mucosa. The partial sequence of the 28‐kDa protein has been determined. The amino acid sequence of the 28‐kDa protein is similar to that of non‐selenium glutathione peroxidase from bovine ciliary body. The 28‐kDa protein catalyzed decomposition of the hydrogen peroxide as well as organic hydroperoxides by reduced glutathion and seems to be a member of the glutathion peroxidases family.
Ascorbate synthesis‐dependent glutathione consumption in mouse liver
Authors: Bánhegyi Gábor , Csala Miklós , Braun László , Garzó Tamás , Mandl József
Published: April 2003

Ascorbate synthesis causes glutathione consumption in the liver. Addition of gulonolactone resulted in an increase of ascorbate production in isolated murine hepatocytes. At the same time, a decrease in reduced glutathione (GSH) level was observed. In hepatic microsomal membranes, ascorbate synthesis stimulated by gulonolactone caused an almost equimolar consumption of GSH. This effect could be counteracted by the addition of catalase or mercaptosuccinate, indicating the role of hydrogen peroxide formed during ascorbate synthesis in the depletion of GSH. The observed phenomenon may be one of the reasons why the evolutionary loss of ascorbate synthesis could be advantageous.
Expression of porin from Rhodopseudomonas blastica in Escherichia coli inclusion bodies and folding into exact native structure
Authors: Schmid Benedikt , Krömer Markus , Schulz Georg E.
Published: April 2003

The homotrimeric membrane channel porin from Rhodopseudomonas blastica was expressed without signal sequence in Escherichia coli. The protein assembled in inclusion bodies in the cytosol, from which it could be recovered using urea and detergents. After purification by anion‐exchange chromatography, the protein crystallized under wild‐type conditions. The X‐ray structure was determined at 2.2 Å resolution, and a comparison with the known wild‐type structure showed that the recombinant porin is identical at the atomic level. The method yields porin and designed mutants thereof in 100 mg amounts, allowing for detailed functional and mechanistic studies.