bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of unidirectional permeability in asymmetric poly(DL‐lactic acid‐co‐glycolic acid) conduits on peripheral nerve regeneration: An in vitro and in vivo study
Authors: Chang Chen‐Jung , Hsu Shan‐hui , Yen Hung‐Jen , Chang Han , Hsu Shih‐Kuang
Published: April 2007

The high outflow permeability of the nerve conduit used to emit the drained waste generated from the traumatized host nerve stump is critical in peripheral nerve regeneration. Our earlier studies have established that asymmetric conduits fulfill the basic requirements for use as nerve guide conduits. In this study, the inflow characteristics of optimal nerve conduits were further examined using in vivo and in vitro trials. Various asymmetric poly(DL‐lactic acid‐co‐glycolic acid) (PLGA) conduits were controlled by modifying precipitation baths using 0, 20, and 95% isopropyl alcohol, with high‐porosity (permeability), medium‐porosity (high outflow and low inflow), and low‐porosity (permeability), respectively. In the in vitro trial, the Schwann cells and fibroblasts were seeded on either side of the asymmetric PLGA films in a newly designed coculture system that simulated the repaired nerve conduit environment. The results of the directional permeable films indicated the statistically significant proliferation of Schwann cells and the inhibition of the division of fibroblasts in lactate dehydrogenase release and inhibition of 3‐(4,5‐dimethylthiazol‐2‐yl)2,5‐diphenyl‐tetrazolium bromide (MTT) reduction, compared with the other films. In the in vivo trial, the PLGA conduits seeded with Schwann cells were implanted into 10 mm right sciatic nerve defects in rats. After 6 weeks, implanted conduits were harvested. Histological examination verified that directional permeable conduits had markedly more A‐type and B‐type myelin fibers in the midconduit and distal nerve. In this work, the directional transport characteristics were established as an extremely important factor to the design and development of optimal nerve guide conduits in peripheral nerve regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Quantum correction to the pair distribution function
Authors: Levashov V. A. , Billinge S. J. L. , Thorpe M. F.
Published: April 2007

We report a numerical technique that allows the quantum effects of zero‐point motion to be incorporated into Pair Distribution Functions calculated classically for molecules using Monte Carlo or Molecular Dynamics simulations. We establish the basis for this approximation using a diatomic molecule described by a Morse potential. The correction should significantly improve the agreement between modeled and experimental data, and facilitate conclusions about inter‐ and intra‐molecular motion and flexibility. We describe a similar approach to obtain the energy and the specific heat. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Nuclear localisation and pDNA condensation in non‐viral gene delivery
Authors: Collins Elizabeth , Birchall James C. , Williams Julie L. , Gumbleton Mark
Published: April 2007

Background

Non‐viral gene delivery vectors are multi‐component systems reflecting various functionalities required for effective cell transfection, including DNA condensation, promotion of cell membrane interactions and provision for subcellular targeting through endosomal escape and/or nuclear delivery. Elements mediating these functions will clearly display inter‐dependency. In this study we sought to explore the relationship within non‐viral vectors of condensation and nuclear localisation.

Methods

Binary, tertiary and quaternary vectors were prepared with combinations of pDNA, DOTAP lipid, the polycation peptide protamine and either SV40 nuclear localisation sequence peptide (‘SV40 NLS’) or a one amino acid substituted mutant of SV40 NLS (‘mutant sequence’). The efficiency of pDNA condensation was determined by gel electrophoresis and quantitative fluorescence spectroscopy. Transfection efficiency was examined in mammalian cells in vitro using standard methods, by electroporation to bypass the plasma membrane barrier and in cells arrested in G0/G1 cell cycle phase to examine the effect of cell division and nuclear membrane disruption.

Results

Small NLS peptide sequences, despite possessing a significant proportion of basic amino acids, display minimal pDNA‐condensing ability when compared to larger polycations such as protamine. In standard in vitro cell adherent transfection studies the predominant elements affording enhanced gene expression were effective pDNA condensation and lipid enhancement of cell membrane interactions. These features conversely hinder efficient gene expression in cells that have undergone electroporation. The benefit of SV40 NLS was only apparent when used in non‐dividing cell populations.

Conclusions

Whilst effective levels of non‐viral‐mediated gene expression generally rely on efficient condensation of pDNA and enhanced interactions with cellular membranes, non‐covalently associated NLS within a multi‐component non‐viral gene vector appears to contribute benefit in sustaining gene expression in non‐dividing cells. Copyright © 2007 John Wiley & Sons, Ltd.
Protein kinase C activity affects neurotransmitter release at polyinnervated neuromuscular synapses
Authors: Santafé M.M. , Garcia N. , Lanuza M.A. , Tomàs J.
Published: March 2007

By using intracellular recording, we studied how protein kinase C (PKC) activity affected transmitter release in singly and dually innervated endplates of the Levator auris longus muscle of 5–6‐day‐old rats during axonal competition in the postnatal synaptic elimination period. In dually innervated fibers, a second endplate potential (EPP) may appear after the first one when the stimulation intensity is increased. The nerve terminals that generate the lowest and the highest EPP amplitudes are designated “small‐EPP generating ending” (SEGE) and “large‐EPP generating ending” (LEGE), respectively. Blocking PKC with calphostin C, staurosporine, or chelerythrine results in an increased release from SEGE (∼80%), whereas release from LEGE and from endings generating only one EPP (OEGE) is not significantly affected. Blocking PKC also leads to the recruitment of silent synapses (acetylcholine cannot be released before PKC inhibition). The mean number of functional axon terminals per synapse increases by ∼47%, and these are now designated the “recruited‐EPP generating endings” (REGE). This suggests that axonal PKC can modulate postnatal synaptic elimination by favoring the nerve terminal disconnection of certain weak axonal endings (REGE and SEGE). We conclude that a PKC‐mediated mechanism should occupy a pivotal place in neonatal synapse elimination, because functional axonal withdrawal can indeed be turned back by PKC block. © 2007 Wiley‐Liss, Inc.
Confocal Raman microscopy: how to correct depth profiles considering diffraction and refraction effects
Authors: Gallardo Alberto , Spells Stephen , Navarro Rodrigo , Reinecke Helmut
Published: April 2007

A new approach to obtain corrected depth profiles by confocal Raman microscopy, which considers diffraction and refraction effects is presented.

The problem of diffraction effects encountered intrinsically in the confocal configuration can be described using a linear Fredholm integral equation of the first kind, which correlates apparent and true Raman intensities with the depth resolution curve of the instrument. Refractive index differences between air and the polymer sample, which cause further errors in the obtained depth profile due to strong aberration effects have been considered. This has been carried out using an empirical variation of the depth resolution function, which is able to simulate the broadening of the depth of focus with depth and also the discrepancy between nominal and measured depth scales.

It is shown that considerable differences between apparent and corrected depth profiles exist at the surface and that these depend on the gradient of the profile and the depth resolution of the Raman microscope. Copyright © 2007 John Wiley & Sons, Ltd.
Formal strategic planning: annual raindance or wheel of success?
Authors: O'Regan Nicholas , Ghobadian Abby
Published: April 2007

The findings from the research presented in this paper indicate that strategic planning is now an established management tool with over half of all small and medium size enterprises (SMEs) engaging in formal strategic planning.

However, some SMEs fail to consider or include some vital components in their strategic plans, leading to the conclusion that many formal strategic plans are little more than a paper exercise.

From an operational perspective, formal strategic planning firms place a higher emphasis on the attributes of strategic planning. However, there are no significant differences on the barriers to strategy implementation in formal or non‐formal planning firms.

Copyright © 2007 John Wiley & Sons, Ltd.
Understanding mission command: a model for developing competitive advantage in a business context
Authors: Yardley Ivan , Kakabadse Andrew
Published: April 2007

Academic and business journals have extensively covered the requirements for the successful implementation of business strategies without arriving at a consensus as to how this objective should be achieved. In Nutt's (2002) 20‐year research on the decision‐making process he found that over 50% of the decisions made by corporate leaders failed. The author contends that failed or poor decisions are directly linked to the way those decisions are implemented and therefore implementation methodology has become a critical business issue.

This paper critically reviews the British Army's implementation methodology which has shown extensive versatility in such circumstances as the Gulf War, the firemen's strike, the foot and mouth crisis and a host of unexpected support operations. This work examines the British Army's definition of mission command, its historical background, the underpinning concepts and the potential utility of such an approach for the private sector. The authors argue that despite the British Army's training and terms of reference it has shown the flexibility and adaptability to achieve success in a volatile and diverse spectrum of tasks. At the heart of the organization's implementation process is mission command.

Copyright © 2007 John Wiley & Sons, Ltd.
Mass spectrometry for enzyme assays and inhibitor screening: An emerging application in pharmaceutical research
Authors: Greis Kenneth D.
Published: April 2007

Robust methods that monitor enzyme activity and inhibitor potency are crucial to drug discovery and development. Over the past 20 years, mass spectrometric methods have increasingly been used to measure enzyme activity and kinetics. However, for rapid screening of inhibitory compounds, various forms of fluorescence and chemiluminscence readout have continued to dominate the market. As the sensitivity, speed, and miniaturization of mass spectrometry methods continue to advance, opportunities to couple mass spectrometry with screening will continue to come to the forefront. To appreciate the tremendous potential for MS‐based screening assays, it becomes necessary to understand the current state of capabilities in this arena. Thus, this review is intended to capture how mass spectrometry for studying enzymes activity has progressed from simple qualitative questions (i.e., is the product detected?) to quantitative measures of enzyme activity and kinetics and then as a tool for rapidly screening inhibitory compounds as an alternative to current methods of high throughput drug screening. © 2007 Wiley Periodicals, Inc., Mass Spec Rev
Analytical strategies for identifying drug metabolites
Authors: Prakash Chandra , Shaffer Christopher L. , Nedderman Angus
Published: April 2007

With the dramatic increase in the number of new chemical entities (NCEs) arising from combinatorial chemistry and modern high‐throughput bioassays, novel bioanalytical techniques are required for the rapid determination of the metabolic stability and metabolites of these NCEs. Knowledge of the metabolic site(s) of the NCEs in early drug discovery is essential for selecting compounds with favorable pharmacokinetic credentials and aiding medicinal chemists in modifying metabolic “soft spots”. In development, elucidation of biotransformation pathways of a drug candidate by identifying its circulatory and excretory metabolites is vitally important to understand its physiological effects. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have played an invaluable role in the structural characterization and quantification of drug metabolites. Indeed, liquid chromatography (LC) coupled with atmospheric pressure ionization (API) MS has now become the most powerful tool for the rapid detection, structure elucidation, and quantification of drug‐derived material within various biological fluids. Often, however, MS alone is insufficient to identify the exact position of oxidation, to differentiate isomers, or to provide the precise structure of unusual and/or unstable metabolites. In addition, an excess of endogenous material in biological samples often suppress the ionization of drug‐related material complicating metabolite identification by MS. In these cases, multiple analytical and wet chemistry techniques, such as LC‐NMR, enzymatic hydrolysis, chemical derivatization, and hydrogen/deuterium‐exchange (H/D‐exchange) combined with MS are used to characterize the novel and isomeric metabolites of drug candidates. This review describes sample preparation and introduction strategies to minimize ion suppression by biological matrices for metabolite identification studies, the application of various LC‐tandem MS (LC‐MS/MS) techniques for the rapid quantification and identification of drug metabolites, and future trends in this field. © 2007 Wiley Periodicals, Inc., Mass Spec Rev
Proteomics in neurosciences
Authors: Drabik Anna , Bierczynska‐Krzysik Anna , Bodzon‐Kulakowska Anna , Suder Piotr , Kotlinska Jolanta , Silberring Jerzy
Published: April 2007

This review provides an outline of the most important proteomic applications in the study of neurodegenerative disorders including Alzheimer's (AD), Parkinson's (PD), Huntington's (HD), and prion diseases, and also discusses advances in cancer and addiction. One of the scopes is to illustrate the potential of proteomics in the biomarkers discovery of these diseases. Finally, this article comments the advantages and drawbacks of the most commonly used techniques and methods for samples preparation. © 2007 Wiley Periodicals, Inc., Mass Spec Rev
Bifurcation of periodic orbits in coupled chemical reactors II
Authors: Friedli A. , Kirchgraber U. , Waldvogel J. , Hagedorn P.
Published: March 2007

In this part of the paper we deal with computational aspects of the bifurcation problem introduced in Part I, cf. [1]. It follows from Section 3 that the bifurcation behaviour is essentially determined by the expression KP(Ω) – ∧β, where β is some constant which was assumed to be nonzero, while P(Ω) is some 2π‐periodic function which was implicitly defined in Section 2. In Section 4 we first derive easily computable expressions for P(Ω) and β from the definitions of Section 2. Secondly we offer a direct, although formal, derivation for these quantities. In Section 5 we briefly show how P(Ω). β can actually be computed by means of a high speed computer and discuss a number of examples. In Section 6 finally we give some asymptotic results for systems depending on an additional parameter.
Approximation of the signorini problem with friction, obeying the coulomb law
Authors: Haslinger J. , Nedlec J.C.
Published: March 2007

The approximation of the Signorini problem with friction by mixed finite element method is studied. The relation between the continuous case and its finite dimensional discretization is analyzed.
An approximation method for the cauchy problem to the three‐dimensional equation of vorticity transport
Authors: Hebeker F.‐K. , Martensen E.
Published: March 2007

The vorticity problem (V0) is shown to have (at least) locally in time a unique classical solution. For numerical purposes global solvability is desired. So by suitable operations we proceed to a family of modified vorticity problems (Vϵ), ϵ > 0, possessing a unique classical solution globally in time.

For (Vϵ) a constructive approximation method is introduced. This procedure yields a sequence (ω) of approximate vorticity fields, converging to the global solution of (Vϵ) and to the local solution of (V0).
Periodic motions of a string vibrating against a fixed point‐mass obstacle: II
Authors: Cabannes H. , Neunzert H.
Published: March 2007

A string fixed at both ends A and B, can oscillate in a plane which there is a fixed point obstacle, placed in the middle of the line AB. The string is initially at rest with a prescribed shape, symmetric with respect to the normal mid‐plane of the segment AB. Using results established before [9] we find new periodic motions.
Stabilization and regularization for solutions of an ill posed problem for the wave equation
Authors: Levine H. A. , Vessella S. , Payne L. E.
Published: March 2007

In this paper we study the problem of finding u: [O, T] → D(A), D(A) ⊆ H, H a Hibert space such that:

magnified image

Is a linear positive, self‐adjoint operator with a compact inverse. The problem is well known to be illposed because uniqueness and existence generally fail. We restore the stability with an a priori bound on ∥ du(0)/dt ∥ for some particular values of T.
A justification of the one‐dimensional linear model of elastic beam
Authors: Tutek Z. , Aganović I. , Nedelec J.‐C.
Published: March 2007

In this paper we prove that the one‐dimensional model of elastic beam is an approximation to the three‐dimensional linear theory of elasticity.
On the approximation method of solving integral equations in diffusion problems
Authors: Bobula E. , Twardowska K. , Piskorek A.
Published: March 2007

In this paper we consider the one‐dimensional problem of heat or mass transport in the system with moving ends. We show that without solving the heat transfer equation, the heat flux flowing out from the system can be found when temperature on the boundary of this system is known. We make use of the Banach contraction theorem for appropriate integral equations. Our method also enables us to find the distribution of temperature in the whole domain that forms the physical system.
Pyrazolo[1,5‐a]pyrimidines. A combined multinuclear magnetic resonance (1H, 13C, 15N, 19F) and DFT approach to their structural assignment
Authors: Sanz Dionisia , Claramunt Rosa M. , Saini Anil , Kumar Vinod , Aggarwal Ranjana , Singh Shiv P. , Alkorta Ibon , Elguero José
Published: April 2007

Multinuclear magnetic resonance spectroscopy together with GIAO‐DFT calculations allowed establishment of the structure of the products obtained by condensation of 3(5)‐amino‐4‐phenyl‐1H‐pyrazole and β‐dicarbonyl compounds bearing a trifluoromethyl group. They are 3‐phenyl‐5‐(R)‐7‐trifluoromethylpyrazolo[1,5‐a]pyrimidines. Copyright © 2007 John Wiley & Sons, Ltd.
Satoyoshi syndrome has antibody against brain and gastrointestinal tissue
Authors: Matsuura Eiji , Matsuyama Wataru , Sameshima Tomoyuki , Arimura Kimiyoshi
Published: April 2007

Satoyoshi syndrome is a rare postnatal disorder with muscle spasms, alopecia, and diarrhea of unknown etiology. Nutritional deficiency seems to influence lifespan. We present a patient with this syndrome having a unique “mesh‐like” mucosal change radiographically and white granules endoscopically in the gastrointestinal tract. A common antibody against brain, stomach, and duodenal tissue, according to Western blot analysis, was detected in the sera of two patients with this syndrome. These findings suggest that Satoyoshi syndrome is a systemic autoimmune disease involving the nervous, endocrine, and gastrointestinal systems. Muscle Nerve, 2007
Adaptive finite element methods for hydrodynamic lubrication with cavitation
Authors: Nilsson Bertil , Hansbo Peter
Published: April 2007

We present an adaptive finite element method for a cavitation model based on Reynolds' equation. A posteriori error estimates and adaptive algorithms are discussed, and numerical examples illustrating the theory are supplied. Copyright © 2007 John Wiley & Sons, Ltd.
Investigation of a changing range genetic algorithm in noisy environments
Authors: Amirjanov Adil
Published: April 2007

This paper analyses the effect of noise on the performance of a changing range genetic algorithm (CRGA). CRGA adaptively shifts and shrinks the size of the search space of the feasible region by employing feasible and infeasible solutions in the population to reach the global optimum. An additional modification of CRGA was introduced to reduce the effects of noise on the performance of the algorithm. Several test cases demonstrated the ability of the improved CRGA to deal with an additive noise. Copyright © 2007 John Wiley & Sons, Ltd.
Efficient 3D‐finite element formulation for thin mechanical and piezoelectric structures
Authors: Braess Dietrich , Kaltenbacher Manfred
Published: April 2007

It is the aim to compute efficiently the deformations of the mechanical structures that are excited or damped by piezoelectric actuators. They are treated as 3D structures to have much flexibility. Special design of the finite element concept is required since the structures are thin walled and locking effects have to be avoided. Although the computations are performed in the framework of 3D elasticity, we use ideas from modern plate elements and mixed methods. Copyright © 2007 John Wiley & Sons, Ltd.
Nonconforming spline collocation methods in irregular domains
Authors: Sun Weiwei , Wu Jiming , Zhang Xiaoping
Published: March 2007

This article studies a class of nonconforming spline collocation methods for solving elliptic PDEs in an irregular region with either triangular or quadrilateral partition. In the methods, classical Gaussian points are used as matching points and the special quadrature points in a triangle or quadrilateral element are used as collocation points. The solution and its normal derivative are imposed to be continuous at the marching points. The authors present theoretically the existence and uniqueness of the numerical solution as well as the optimal error estimate in H1‐norm for a spline collocation method with rectangular elements. Numerical results confirm the theoretical analysis and illustrate the high‐order accuracy and some superconvergence features of methods. Finally the authors apply the methods for solving two physical problems in compressible flow and linear elasticity, respectively. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007
Pressure projection stabilizations for Galerkin approximations of Stokes' and Darcy's problem
Authors: Burman Erik
Published: March 2007

In this study, we consider some recent stabilization techniques for the Stokes' problem and show that they are instances of the framework proposed by Brezzi and Fortin in “A minimal stabilisation procedure for mixed finite element methods” (Numer Math 89, (2001) 457). We also propose an analysis for Taylor‐Hood elements with discontinuous pressures stabilized using penalization of the interelement pressure jumps. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007
Control of particle size in the formation of polymer latices
Authors: Goodwin James W. , Ottewill Ronald H. , Pelton Robert , Vianello Givvanni , Yates David E.
Published: April 2007

A brief survey is given of the methods which can be used to produce polymer latices with a narrow size distribution. The factors which control both the particle size and the nature of the chemical groupings on the latex particle surface are discussed for latices prepared without the addition of an emulsifier. In particular, it is demonstrated experimentally that the ionic strength of the aqueous phase plays a major role in controlling particle size and that the free radicals produced by thermal decomposition of the initiator become incorporated as end‐groups on the polymer chains and hence form the surface groups on the particle. A theoretical explanation is given which indicates the reasons for the importance of ionic strength in controlling particle size.
The Thermal Decomposition of some Dialkyl Dicarbanilates
Authors: Jiricny Josef , Reese Colin B.
Published: April 2007

The thermal decomposition at 300 C of five dicarbanilates derived from 4,4 '— diphenylmethane diisocyanate (MDI) was studied in an attempt to elucidate the low‐temperature decomposition mechanism of rigid MDI‐based polyurethane foams. The dicarbanilates of primary and secondary alcohols decomposed via normal fission of the urethane linkages, whereas those of tertiary alcohols yielded 4,4′—diphenylmethane diamine (MDA), carbon dioxide and the appropriate olefin via abnormal fission of the carbanilates.
Gelation and Crystallisation of Nylon‐6 from Dilute Solution
Authors: Stamhuis Jan E. , Pennings Albert J.
Published: April 2007

Dilute solutions of nylon‐6 in benzyl alcohol transform to heavy transparant gels upon cooling, in contrast to the solutions in 1,4‐butanediol, which yield flaky precipitates in a similar concentration range.

Differential scanning calorimetry and electron microscopy indicate that the gels are composed of an interlacement of thin fibrillar crystals with constant lateral dimensions partially aggregated in larger ribbons. On the other hand, a sheaflike morphology, characterised by strongly tapered and corrugated lath shaped crystals, developed in 1, 4‐butanediol. The crystals from both solvents have the monoclinic α‐structure with the hydrogen bonds parallel to the long axis and the chains perpendicular to the growth direction.

The difference in morphology of the present crystals is explained by specific interaction of the benzyl alcohol and 1,4‐butanediol molecules on the growing crystal faces in the laterial as well as the H‐bond direction.
Preclinical Evaluation of Polymer Membranes and Coatings
Authors: Courtney James M.
Published: April 2007

In vitro testing for in vivo purposes is considered with reference to the preclinical evaluation of polymers used as membranes in haemodialysis and polymers used to coat activated carbon granules for haemoperfusion. The respective roles of the polymer membrane and polymer coating are contrasted.

The design of haemodialysis membranes and the assessment of dialysis, ultrafiltration and mechanical properties and blood compatibility are examined. Blood compatibility assessment is described in terms of a procedure for estimating platelet retention.

The selection of polymer coatings for activated carbon granules is considered. The in vitro testing of coatings is described by reference to techniques for estimating the influence of a polymer coating on solute removal rates by adsorption, the generation of fine carbon particles and blood compatibility.
Light scattering characterisation of polymers I. An extension of the zimm plot
Authors: Suzuki Hidematsu
Published: April 2007

A new method is proposed for extrapolating light‐scattering data to the zero angle of scattering. Essentially the method consists of iterative extrapolations by use of the regression method as a subroutine, and it applies in general to the data obtained at low polymer concentrations and at low angles of scattering. Light‐scattering results on high molecular weight linear polystyrene in benzene were successfully analysed with the method. In comparison with other published methods, the strong points and limitations of the method are discussed.
Elastomer adhesives
Authors: Welch Malcolm J.
Published: April 2007

Some information about the general and specific aspects of polychloroprene contact adhesive composition is given. Reference is made to application viscosity, the chemical and specific adhesive purpose of ingredients and performance related to composition and the method of stress. Some preliminary results, about the study of methods for determining how adhesive films form from complex mixtures are included.
The science of acrylic adhesives
Authors: Lees William A.
Published: April 2007

The paper reviews the major developments published in the Patent literature over the last thirty years insofar as these reflect the evolution of the so‐called anaerobic and cyanoacrylate adhesives and the recent introduction of the ‘toughened’ acrylic adhesives.

Reaction mechanisms are postulated and the problems of formulation and production discussed in detail together with the performance characteristics of the individual adhesive types.
Studies on the rigidity of gelatine gels
Authors: Tar Ildikó , Wolfram Ervin
Published: April 2007

Gelatine gel samples formed in contact with phases of various polarity such as glass, plexiglass (PMMA) and air have been studied by a Röth‐type micro‐penetrometer. The experimental results showed that the penetrability of the gels was significantly effected by the adjacent phase. Comparing the data with those found on a freshly cut surface representing the bulk of the gel it can be assumed that the differences are caused by different orientation of the gelatine molecules in the penetrated region. In order to prove this assumption gels containing sodium chloride, sodium sulphate and sodium dodecyl sulphate, respectively were prepared. It has been shown that the rigidity of the gel/air surface and that of the bulk was effected similarly but not equally by the salts.

In order to learn the processes occurring in presence of the above mentioned cosolutes turbidity measurements were carried out on all samples using a Pulfrich nephelometer.
Polymers with mesogenic elements and flexible spacers in the main chain: Aromatic‐aliphatic polyesters
Authors: Meurisse P. , Noel C. , Monnerie L. , Fayolle B.
Published: April 2007

A new series of aromatic‐aliphatic polyesters of general structure:

magnified image

R1 = terphenyl, biphenyl, stilbene

R2 = (CH2)n;  CH2C(Me)2CH2;CH2;C(Et)2CH2; (CH2CH2O)n CH2CH2 has been synthesised. The existence of thermotrpic liquid crystalline phases has been shown by polarised light microscopy. The texture observations have suggested the existence of nematic, SA or/and SC phases depending on the chemical structure. The temperature of transition between the phases and, as a consequence, the range of mesomorphism are highly dependent upon the chemical structure. The clearing point is high, even for the longest aliphatic group, while the melting point is depressed.
Preparation of lithium and sodium phosphate‐polyphenylphosphonate hybrid glasses
Authors: Currell Brian R. , Grzeskowiak Roman , Lynn Michael E.
Published: April 2007

The interaction of phenylphosphonic dichloride and sodium or lithium phosphate gives glassy polymers which are hybrids of lithium and sodium metaphosphate glasses and polyphenylphosphonates. Tg's increases as the proportion of the alkali metal incorporated in the polymer increases. Reaction is most conveniently carried out by heating in chloroform under reflux. Polymers were prepared with up to 1 in 5 of the phosphorus atoms associated with Li+and up to 1 in 6 associated with Na+. Glasses could also be formed by reaction in the absence of solvent but difficulty was experienced in the complete removal of hydrogen chloride.
Preparation of monodisperse polymer samples by solubility difference method
Authors: Kamide Kenji , Miyazaki Yukio , Abe Tatsuyuki
Published: April 2007

An attempt was made to prepare the polymer fractions having extremely sharp molecular weight distribution (MWD), by using a successive solutional fractionation (SSF) method, in which a polymer‐lean phase was separated as a fraction from a polymer‐rich phase. For this purpose a large‐scale preparative SSF apparatus was constructed. Atactic polystyrene (PS) high‐density polyethylene (PE), and cellulose di‐ and tri‐acetates (CDA and CTA) were fractionated by SSF. The fractions isolated from a quasi‐binary mixture (polymer/solvent system) have the same MWD as that predicted by the computer simulation technique. Even under the conventional fractionation conditions (initial polymer volume fraction vop = ∼ 0.01, total number of fractions nt = 10 ∼ 20) the fractions with the ratio of the weight to number‐average molecular weight Mw/Mn less than 1.1 for PS, 1.2 for PE, 1.3 for CDA and 1.4 for CTA were obtained, with exception of a few initial fractions. The advantage of the SSF method was clarified over the conventional preparative methods such as gel permeation chromatography and the column fractionation method.
The N‐ and C‐termini of the human Nogo molecules are intrinsically unstructured: Bioinformatics, CD, NMR characterization, and functional implications
Authors: Li Minfen , Song Jianxing
Published: March 2007

RTN4 or Nogo proteins are composed of three alternative splice forms, namely 1192‐residue Nogo‐A, 373‐residue Nogo‐B, and 199‐residue Nogo‐C. Nogo proteins have received intense attentions because they have been implicated in a variety of critical cellular processes including CNS neuronal regeneration, vascular remodeling, apoptosis, interaction with β‐amyloid protein converting enzyme, and generation/maintenance of the tubular network of the endoplasmic reticulum (ER). Despite their significantly‐different N‐terminal lengths, they share a conserved C‐terminal reticulon‐homology domain consisting of two transmembrane fragments, a 66‐residue extracellular loop Nogo‐66 and a 38‐residue C‐tail carrying ER retention motif. Nogo‐A owns the largest N‐terminus with 1016 residues while the Nogo‐B has an N‐terminus almost identical to the first 200 residues of Nogo‐A. So far, except for our previous determination of the Nogo‐66 solution structure, no structural characterization of the other Nogo regions has been reported. In the present study, we initiated a systematically investigation of structural properties of Nogo molecules by a combined use of bioinformatics, CD, and NMR spectroscopy. The results led to two striking findings: (1) in agreement with bioinformatics prediction, the N‐ and C‐termini of Nogo‐B were experimentally demonstrated to be intrinsically unstructured by CD, two‐dimensional 1H 15N NMR HSQC, hydrogen exchange, and 15N heteronuclear NOE characterization. (2) Further studies showed that the 1016‐residue N‐terminus of Nogo‐A was again highly disordered. Therefore, it appears that being intrinsically‐unstructured allows Nogo molecules to serve as double‐faceted functional players, with one set of functions involved in cellular signaling processes essential for CNS neuronal regeneration, vascular remodeling, apoptosis and so forth and with another in generating/maintaining membrane‐related structures. We propose that this mechanism may represent a general strategy to place the formation/maintenance of membrane‐related structures under the direct regulation of the cellular signaling. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Effect of thermal annealing and nitrogen content on amorphous silicon thin‐film crystallization
Authors: Bouridah H. , Mansour F. , Mahamdi R. , Bounar N. , Temple‐Boyer P.
Published: April 2007

We study the influence of high‐temperature annealing (1100–1200 °C) on the crystallization of nitrogen‐doped silicon films deposited by LPCVD (low‐pressure chemical vapor deposition) at low temperature (465 °C) from disilane Si2H6 and ammonia NH3. Scanning electron microscopy (SEM) and X‐ray diffraction, studies of films are used to analyze crystallinity evolution and grain orientations. Results show the transformation of films deposited in amorphous phase to a typically polycrystalline structure after high‐temperature annealing with a large grain size exceeding 1 μm. The structural properties are strongly influenced by the annealing conditions and the nitrogen ratio in each film. It is shown that the film crystallinity increases with the duration of annealing, and that the nitrogen content inhibits the crystallization phenomena. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐compensation processes in CdTe〈In〉 crystals
Authors: Fochuk P. , Verzhak Ye. , Panchuk O.
Published: April 2007

High temperature equilibrium in situ in CdTe〈In〉 single crystals in a wide range of temperature (700–1200 K) and dopant content (6 × 1016∼1020 at/cm3) was studied. Self‐compensation processes, which occur at these conditions, were modelled using quasichemical defect reaction theory. During heating the self‐compensation degree passed through a minimum under Cd saturation and increased under Te saturation. The annealing under Te saturation allowed obtaining high resistive material of both conductivity types. The lowest charge carrier density was equal to ∼3 × 109 cm–3 and the self‐compensation degree reached 100%. Point defect structure modelling showed a good agreement for both high temperature equilibrium and quenched state. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase transitions in ZnTe co‐doped with Mg and oxygen
Authors: Elyukhin V. A. , Sorokina L. P. , Rodriguez de Santiago M.
Published: April 2007

Self‐assembling of 1O4Mg tetrahedral clusters in ZnTe isoelectronically co‐doped with Mg and oxygen in the ultra dilute oxygen impurity limit is described by a phase diagram. The occurrence of 1O4Mg clusters is a result of the second‐order transition. The final stage of self‐assembling when all oxygen impurities are in 1O4Mg clusters has to be reached also as a result of the second‐order transition at the temperature close to the temperature of the occurrence of these clusters. The conditions of these phase transitions are obtained. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of parsley (Petroselinum crispum (Mill.) Nym. ex A.W. Hill, Apiaceae) extracts on some biochemical parameters of oxidative stress in mice treated with CCl4
Authors: Popović Mira , Kaurinović Biljana , Jakovljević Vida , Mimica‐Dukic Neda , Bursać Marija
Published: April 2007

The in vitro and in vivo antioxidant activity of different extracts of leaves and root of parsley (Petroselinum crispum (Mill.) Nym. ex A.W. Hill, Apiaceae) were studied. Free radical scavenging capacity (RSC) was evaluated measuring the scavenging activity on the 2,2‐diphenyl‐1‐picrylhydrazil (DPPH) and OH radicals. Also, the effects on lipid peroxidation (LP) were evaluated. The results obtained showed that all examined extracts act as good scavengers of DPPH and OH radicals and reduce the intensity of LP. The in vivo effects were evaluated on some antioxidant systems (activities of LPx, GSH‐Px, Px, CAT and XOD, and GSH content) in the mice liver and blood after treatment with the examined parsley extracts, or in combination with carbon tetrachloride (CCl4). On the basis of the results obtained it can be concluded that the examined extracts exhibited a certain protective effect. However, combined treatments with CCl4 and the examined extracts showed both positive and negative synergism, inducing or suppressing the influence of CCl4 alone. Copyright © 2007 John Wiley & Sons, Ltd.
Antinociceptive and antipyretic activities of the Zizyphus oxyphylla Edgew. leaves
Authors: Nisar M. , Adzu B. , Inamullah K. , Bashir A. , Ihsan A. , Gilani A. H.
Published: April 2007

A methanol extract of Zizyphus oxyphylla Edgew leaves has been investigated for its analgesic and antipyretic activities in Adult Wistar and Swiss albino mice of either sex at 50, 100 and 200 mg/kg orally. The extract demonstrated marked antipyretic activity against Brewer's yeast‐induced pyrexia in rats. The extract demonstrated significant peripheral analgesic effect in the acetic acid‐induced writhing test in mice. The phytochemical tests revealed that the extract contained alkaloids, anthraquinones, flavonoids, glycosides, phenols, resins, saponins and tannins using standard procedures. In conclusion, the present study suggests that the methanol extract of Zizyphus oxyphylla Edgew leaves possesses potent antipyretic and antinociceptive activities and thus validates its use in the treatment of pain and fever. Copyright © 2007 John Wiley & Sons, Ltd.
Convective Available Potential Energy (CAPE) in mixed phase cloud conditions
Authors: Früh B. , Wirth V.
Published: April 2007

An approximate but pragmatic approach is presented to define Convective Available Potential Energy (CAPE) in mixed phase cloud conditions. The underlying process calls for mixed (i.e. liquid and ice) phase parcels and assumes the liquid fraction to be a unique function of temperature. The approach is meant to represent average conditions. Differences between this and more traditional approaches are quantified and discussed for mean tropical conditions.

Generally freezing increases parcel temperature and, hence, buoyancy. If freezing occurs isobarically (as was often assumed in the past), all water changes phase at a single level resulting in a discontinuity in buoyancy at that level. By contrast, the mixed phase parcel process implies a continuous phase transition in a finite range of temperatures Tfs ≥ T ≥ Tfe, leading to a gradual change of buoyancy with altitude and preventing any temperature inversion. The details of this gradual change depend on the choice of the specified temperature range [Tfs, Tfe]. High in the troposphere, where all water is frozen irrespective of the details, the differences between the buoyancy profiles are small (but finite).

CAPE is very sensitive to the treatment of the freezing process. Isobaric freezing at a relatively high temperature (e.g. − 5 °C) in a reversible process may increase CAPE by a factor of 2 to 3, and this increase is similar in magnitude to the difference between the pseudo‐adiabatic and the reversible processes for pure water parcels. Both of these processes are considered less realistic than the reversible mixed phase process with continuous freezing over a broad temperature range [Tfs, Tfe] = [−5 °C, − 40 °C]; the corresponding CAPE lies about half way between the reversible and irreversible pure water processes. For clouds with finite precipitation efficiency the effect of freezing is less pronounced than for reversible conditions. Copyright © 2007 Royal Meteorological Society
Hydrogen‐bond interactions in THF–H2O–HF: A theoretical study
Authors: Sahu Prabhat K. , Lee Shyi‐Long
Published: March 2007

The electronic structure calculations for the hydrogen‐bond interactions of tetrahydrofuran (THF), water (H2O), and hydrogen fluoride (HF) have been reported using density functional theory (DFT) method. Three different stable clusters that result from strong intermolecular interactions of the ternary THF/H2O/HF system have been considered: (I) THF–H2O–HF, (II) THF–HF–H2O, and (III) H2O–THF–HF. The optimized geometries, vibrational frequencies, and interactions of these hydrogen‐bonded van der Waals systems are reported. Moreover, a quantitative account on the roles of hydrogen bond cooperativity on the three different stable structures has been analyzed through energy decomposition scheme at MP2/aug‐cc‐pVDZ//B3LYP/aug‐cc‐pVDZ. The BSSE‐corrected total binding energy sequence for these structures are found as 19.58 kcal/mol >19.16 kcal/mol > 16.72 lcal/mol for II > I > III, respectively. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
The effect of tea tree oil and antifungal agents on a reporter for yeast cell integrity signalling
Authors: Straede Andrea , Corran Andy , Bundy James , Heinisch Jürgen J.
Published: April 2007

Cell integrity in Saccharomyces cerevisiae is ensured by a rigid cell wall whose synthesis is controlled by a highly conserved MAP kinase signal transduction cascade. Stress at the cell surface is detected by a set of sensors and ultimately transmitted through this cascade to the transcription factor Rlm1, which governs expression of many genes encoding enzymes of cell wall biosynthesis. We here report on a number of versatile reporter constructs which link activation of a hybrid, Rlm1–lexA, by the MAP kinase Mpk1/Slt2 to the expression of the bacterial lacZ gene. This system was adapted to automated microwell screening and shown to be activated by a number of compounds inhibiting cell wall biosynthesis or interfering with plasma membrane function. In addition, we tested tea tree oil and two of its purified constituents (α‐terpineol, terpinen‐4‐ol) for their effects on growth and on cell integrity signalling using such reporter strains. Tea tree oil was found to inhibit growth of wild‐type and slg1/wsc1 mutant cells at a threshold of approximately 0.1% v/v, with the purified compounds acting already at half these concentrations. A mid2 deletion displayed hyper‐resistance. Tea tree oil also induces the signalling pathway in a dose‐dependent manner. Copyright © 2007 John Wiley & Sons, Ltd.
Trans‐isomerization of oleic acid and potassium oleate by ionizing radiation
Authors: Pan Huo‐Ping , Goldblith Samuel A. , Proctor Bernard E.
Published: April 2007

The oleic acid of IV 89.2 was irradiated with cathode rays at doses of 15 × 106 to 70 × 106 rep and was found to have beentrans‐isomerized from 2.5% at 45 × 106 rep to 9.4% at 70 × 106 rep; the oleic acid of IV 89.8 irradiated at doses of 13.4 × 106 to 401.6 × 106 rep and was found to have beentrans‐isomerized to 4.9% at 187.4 × 106 rep and to 14.6% at 401.6%.

Thetrans‐isomerization was independent of oxygen.

Aqueous solutions of potassium oleate at 1% concentration were irradiated with doses from 1 × 106 rep to 5 × 106 rep. The oleic acid recovered from the irradiated solutions was found to have beentrans‐isomerized from 8.1% at 1 × 106 rep to 1.9% at 5 × 106 rep; the oleic acid recovered from the 2.5% solutions was found to have beentrans‐isomerized to 8.3% at 5 × 106 rep, 11.9% at 10 × 106 rep, and 0.1% at 30 × 106 rep.

A modified “baseline” technique in infrared spectrophotometric analysis is described.
Laboratory extraction of cottonseed with various petroleum hydrocarbons
Authors: Ayers A. L. , Dooley J. J.
Published: March 2007

Solvent extraction of cottonseed with various hydrocarbons in the C5 to C7 range was studied to determine comparative yields and quality of oil produced with pure and commercial hydrocarbon solvents. The solvents used were Pure Grade (minimum 99 mol per cent purity) isopentane, normal pentane, cyclohexane, normal heptane, and benzene; Technical Grade (minimum 95 mol per cent purity) neohexane, diisopropyl, 2‐methylpentane, 3‐methylpentane, normal hexane, methylcyclopentane, and a 90 mol per cent cyclopentane; and Commercial Grade normal pentane, isohexanes, normal hexane, isoheptanes, and normal heptane.

The effects of precooking the seeds and of the inclusion of hulls on yield and color of extracted oil were determined. Yields and colors of crude oils from cottonseed with both high and intermediate free fatty acid content were studied, and characteristics of the oils determined and compared. Refining losses, refined colors, and bleach colors of oils extracted with various hydrocarbons were compared. Color comparisons were made with a Gardner Color Comparator and a Fisher Electrophotometer. Other test methods used were modifications of official A.O.C.S. methods adapted to small samples. In general normal paraffins and isoparaffins were found to have some advantages over cyclic hydrocarbons.