bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Solid State Properties of Novel Fluorescent Polyester Star Polymers
Authors: Klok Harm‐Anton , Becker Stefan , Schuch Falk , Pakula Tadeusz , Müllen Klaus
Published: December 2003

Two novel tetra‐ and hexahydroxy functionalized perylene chromophores have been used as initiators for the Sn(oct)2 catalyzed ring‐opening polymerization of different lactones. The arms of the resulting star polymers were comprised of either crystallizable poly(L‐lactide) or poly(ε‐caprolactone) arms or of amorphous poly[γ‐(tert‐amyl)‐ε‐caprolactone] chains. The star polymers were investigated by differential scanning calorimetry, X‐ray scattering and dynamic mechanical and optical spectroscopy. Whereas the thermal properties of the poly(ε‐caprolactone) stars were barely affected by the star topology, crystallization of the poly(L‐lactide) stars was strongly hindered by the star‐shaped architecture. Interestingly, for the amorphous poly[γ‐(tert‐amyl)‐ε‐caprolactone] stars a decrease in Tg with increasing chain length was found, reflecting the declining influence of the rigid perylene core on segmental mobility with increasing arm length. While the solid state and solution optical properties of high molar mass polyester stars were identical, the excitation and fluorescence emission spectra of spin‐coated films of the low molecular weight polymers revealed a red shift, pointing towards perylene – perylene interactions in these samples. The optical spectroscopy experiments suggested that arm length, rather than the number of arms, is the most important parameter determining encapsulation and preventing aggregation of the perylene core moieties in the solid state.

magnified image
Hydrophilic Poly(ether‐ester)s and Poly(ether‐ester‐amide)s Derived from Poly(ε‐caprolactone) and COCl Terminated PEG Macromers
Authors: Crisci Leonilda , Volpe Claudio Della , Maglio Giovanni , Nese Giuseppe , Palumbo Rosario , Rachiero Giovanni P. , Vignola Maria C.
Published: December 2003

A series of poly(ε‐caprolactone) (PCL)‐based multiblock poly(ether‐ester)s (PEE)s and poly(ether‐ester‐amide)s (PEEA)s were obtained from α,ω‐dihydroxy‐PCL ($\overline M _{\rm n}$ = 2–4 kDa) and COCl di‐terminated poly(ethylene oxide) (PEO) macromers (MAC) of different length ($\overline M _{\rm n}$ = 150, 300, 600, 1 000 Da). 4,7,10‐Trioxa‐1,13‐tridecanediamine was used in the synthesis of PEEAs. Bulk polycondensation processes were accomplished by one step (PEE) and two step (PEEA) procedures. PEEAs with PCL/MAC/Trioxy molar ratios 1:2:1 and 1:3:2 were investigated. The multiblock copolymer architecture was proved by 1H NMR and size exclusion chromatography (SEC) techniques. Unimodal molecular weight (MW) distributions and $\overline M _{\rm n}$ values in the range of 13.3–21.0 kDa (PEE) and 8.1–12.8 kDa (PEEA) were found. Crystalline PCL‐type phases were identified for both PEEAs and PEEs by X‐ray diffraction. The thermal transitions were investigated by differential scanning calorimetry (DSC). The Tm values (49.9–53.4 °C) reflect those of the PCL component while the Tg of PEEAs (−45 to −52 °C) are higher than those of the PEEs (−58 to −61 °C) or the macromers. The equilibrium water uptakes range from 1.0 to 18.4 wt.‐% (PEE) and from 4.4 to 8.8 wt.‐% (PEEA) depending on both the composition and length of the ethylene oxide sequences. A dependence of surface homogeneity on copolymer composition was found for PEEs by dynamic contact angle measurements.

The preparation of PEEAs and PEEs.

magnified image

The preparation of PEEAs and PEEs.
Laccase‐catalyzed Synthesis and Antioxidant Property of Poly(catechin)
Authors: Kurisawa Motoichi , Chung Joo Eun , Uyama Hiroshi , Kobayashi Shiro
Published: December 2003

Catechin was oxidatively polymerized by laccase in a mixture of a polar organic solvent and buffer to give a new class of flavonoid polymers. Myceliophthora laccase showed high catalytic activity for the polymerization. Using a mixed solvent of acetone and pH 5 acetate buffer efficiently produced the polymer. Under the selected conditions, DMF‐soluble polymers were obtained in good yields. Effects of reaction parameters on the yield, solubility, and molecular weight of the polymer have been systematically investigated. A radical species was detected in the polymer by ESR spectroscopy. The polymers showed greatly amplified superoxide scavenging activity and xanthine oxidase inhibitory activity compared with monomeric catechin.

Superoxide scavenging activity of poly(catechin)s, n = 3. ○: catechin, □: poly(catechin).

magnified image

Superoxide scavenging activity of poly(catechin)s, n = 3. ○: catechin, □: poly(catechin).
Synthesis and Characterization of β‐Cyclodextrin Based Functional Monomers and its Copolymers with N‐isopropylacrylamide
Authors: Liu Yu‐Yang , Fan Xiao‐Dong , Gao Lei
Published: December 2003

Two novel monovinyl β‐cyclodextrin (β‐CD) monomers are synthesized. Their chemical compositions are characterized by means of element analysis, NMR and FT‐IR spectroscopy. The results show that the synthesis techniques used are convenient and efficient. Using N‐isopropylacrylamide as a comonomer, two novel linear copolymers can also be synthesized.

Synthesis route of monovinyl β‐CD monomers.

magnified image

Synthesis route of monovinyl β‐CD monomers.
2‐[(1‐Imidazolyl)formyloxy]ethyl Methacrylate as Selective Methacryloylating Agent: Kinetics of Reaction with Model Alcohols and Amines
Authors: Ranucci Elisabetta , Grigolini Michela , Ferruti Paolo
Published: December 2003

The kinetics of the coupling reactions of 2‐[(1‐imidazolyl)formyloxy]ethyl methacrylate (HEMA‐Im) with model primary and secondary alcohols and amines have been investigated both in the absence and in the presence of imidazole and triethylamine as catalysts. In the absence of added catalysts, alcohols either reacted very sluggishly or did not react at all with HEMA‐Im, but amines reacted completely in relatively short times. In the presence of catalysts, both primary and secondary alcohols underwent coupling reactions with HEMA‐Im, the former about ten times faster than the latter. Imidazole was a more effective catalyst than triethylamine. HEMA‐Im's ability to discriminate between amino and hydroxyl groups was tested with 4‐amino‐1‐butanol: the 1H NMR analysis of the reaction product confirmed 100% selectivity towards the amino group. It was therefore concluded that HEMA‐Im is a highly selective methacryloylating agent, with a synthetic potential for preparing multifunctional monomers and polymers.

Reaction curves for HEMA‐Im with EtOH and PriOH at 37 °C in the presence of imidazole (HEM5 and HEM6) and triethylamine (HEM7 and HEM8).

magnified image

Reaction curves for HEMA‐Im with EtOH and PriOH at 37 °C in the presence of imidazole (HEM5 and HEM6) and triethylamine (HEM7 and HEM8).
Linear Terpyridine‐Ruthenium(II) Poly(ethylene glycol) Coordination Polymers
Authors: Hofmeier Harald , Schmatloch Stefan , Wouters Daan , Schubert Ulrich S.
Published: December 2003

In the present contribution, we synthesized linear coordination polymers based on oligo(ethylene glycol)s as well as poly(ethylene glycol)s and terpyridine ruthenium(II) complexes. The reaction conditions, e.g., solvent, concentration, were varied to obtain well‐soluble, high molecular weight polymers. The resulting compounds were characterized by UV‐vis and NMR spectroscopy. The viscosity of the materials was also investigated with and without salt addition. Finally, the polymers were characterized with DSC and AFM. AFM revealed a lamellar morphology.

magnified image
Synthesis and Dielectric Study of New Liquid‐crystalline Polysiloxanes Presenting a Thioether Spacer
Authors: Gilles Paul‐Philippe , Milano Jean‐Claude , Vernet Jean‐Louis
Published: December 2003

Three new cyanobiphenyl polysiloxanes presenting long thioether spacers have been carried out. This type of spacer leads to very stable liquid‐crystalline polymers at room temperature and remove the crystallinity phenomenon. Dielectric analysis results show that the thioether spacer brings much more molecular flexibility to the system.

Example of an “interdigitated” structure observed by X‐ray analysis.

magnified image

Example of an “interdigitated” structure observed by X‐ray analysis.
Conformations of Highly Charged Dendronized Polymers in Aqueous Solutions of Varying Ionic Strength
Authors: Girbasova Nina , Aseyev Vladimir , Saratovsky Sergey , Moukhina Irina , Tenhu Heikki , Bilibin Alexander
Published: December 2003

Conformations of two linear, charged dendronized polymers in aqueous solutions of different ionic strengths have been studied by light scattering. Both polymers have a polyacrylic core. The repeating unit of the first of the polymers studied contains a residue of aspartic acid bound to a carboxylic group of the core by an amide group as a first‐generation dendron, whereas the second polymer contains second‐generation dendrons constructed of three molecules of aspartic acid. The dendritic polymers adopt different conformations depending on the generation. Polymers with first‐generation dendrons are flexible and their conformation is sensitive to salt. The polymers with dendrons of the second generation adopt a semi‐flexible rod conformation. Their conformation is not sensitive to salt but is determined by the bulkiness of the dendrons.

Polyacrylic polymers having a residue of aspartic acid as a first‐generation dendron (P1), and having a second‐generation dendron on the basis of aspartic acid (P2).

magnified image

Polyacrylic polymers having a residue of aspartic acid as a first‐generation dendron (P1), and having a second‐generation dendron on the basis of aspartic acid (P2).
Preparation of Positively and Negatively Charged Organic Colloids from a Single Precursor
Authors: Röder Thorsten , Kramer Thomas , Huber Klaus , Kitzerow Heinz‐S.
Published: December 2003

A synthetic route is presented for the preparation of electrically charged colloidal particles with either sign from the same precursor. In the first step, methyl methacrylate was copolymerized with ω‐bromoalkyl acrylate and a cross‐linker, leading to monodisperse, bromo‐functionalized colloids. Substitution of the bromo‐functions by either trimethylamine or Na2SO3 transformed the neutral precursors into positively or negatively charged particles, respectively. The charge density could be varied in two ways: (i) by varying the fraction of bromo‐functionalized monomers; (ii) by increasing the degree of substitution of the bromo‐functions. Derivation of the charged particles from the same precursor colloid made it easier to explain various interesting physical properties of the charged colloidal particles. Higher charge densities were achieved for the cationic colloids. If a threshold value for the charge density of 55 μC · cm−2 was surpassed, the particles showed a significant swelling in aqueous solution.

magnified image
Intra‐Molecular Energy Transfer Characteristics of Novel Oligo(thienylphenyl)amine Derivatives Having a Gradient Structure
Authors: Cho Jun‐Sang , Kojima Yojiro , Norifusa Sato , Higuchi Masayoshi , Yamamoto Kimihisa
Published: December 2003

Oligo(thienylphenyl)amine (TTPA) derivatives which have different thiophene units and potential gradient molecules were synthesized. From the investigation of steady‐state absorption and emission properties and the estimation of the free energy and the energy level of the oligomers, the energy transfer efficiency of the oligomers increased with increasing thiophene units, implying that the energy transfer mainly occurs through space due to a large area overlap existing between the absorption and the emission spectra of the oligomers. Furthermore, based on the calculated Rehm‐Weller equation (ΔGen and ΔGel) and energy diagrams of the oligomers, we found that 4TTPA (4), having a 4‐unit thiophene in the backbone, showed higher energy transfer efficiency compared to that of the others.

Molecular structures of TTPA oligomers.

magnified image

Molecular structures of TTPA oligomers.
Ternary Gels of a Polymer Blend and a Recycled Oil: Their Use as Bitumen Modifiers
Authors: Barral Marisol , Santamaría Anton , Peña Juan Jose , Eugenia Muñoz M.
Published: December 2003

A blend of random ethylene‐vinyl acetate copolymer (EVA) and triblock styrene‐butadiene‐styrene copolymer (SBS) was dissolved in a recycled engine oil to obtain ternary thermoreversible gels. As the temperature was increased, first a network associated with EVA disappeared, and a second one associated with SBS dominated, maintaining the elastic response of the system. The principal advantage of these ternary systems is that their mechanical properties and thermal stability are better than that of binary gels. These gels, made from waste, can be used as bitumen modifiers to obtain binders of improved properties and good stability, which are useful for road surfacing.

Temperature sweeps of elastic modulus performed at a frequency of 1 Hz.

magnified image

Temperature sweeps of elastic modulus performed at a frequency of 1 Hz.
Objective Evaluation of the Efficiency of Cellulase Finishing of Cotton Fabrics Dyed with Reactive Dyes
Authors: Betcheva Rossitza , Stamenova Maria , Boutris Costas , Tzanov Tzanko
Published: December 2003

This work evaluates the effect of cellulase finishing of dyed cotton fabrics. Fabric samples were dyed with reactive dyes possessing different reactive groups with or without metal atoms in their structures. Enzymatic treatments were carried out with total crude cellulase (TC), purified endoglugonase (EG) and cellobiohydrolase (CBH). The Kawabata system (KES) was used to evaluate the effect of enzymatic treatments depending on the pre‐existing dyes on the cotton fabric. Dyed samples differed significantly from the undyed samples in their physico‐mechanical characteristics after the cellulase application. It was found that the geometrical roughness of fabrics could provide a quantitative description of the influence of the reactive dye structure on the cellulase finishing efficiency.

Influence of reactive type group on the relative change of geometrical roughness of dyed fabrics.

magnified image

Influence of reactive type group on the relative change of geometrical roughness of dyed fabrics.
Disentangled State in Polymer Melts; a Route to Ultimate Physical and Mechanical Properties
Authors: Rastogi Sanjay , Kurelec Lada , Cuijpers Juul , Lippits Dirk , Wimmer Markus , Lemstra Piet J.
Published: December 2003

The role of entanglements in obtaining a homogeneous product of ultra high molecular weight polyethylene (UHMW‐PE) has been explored. Studies performed in this report show that a disentangled state before melting is a prerequisite to obtain homogeneous products of an intractable polymer like UHMW‐PE. The disentangled state is obtained directly from the reactor by controlling the polymerisation conditions or in the solid state when there is enhanced chain mobility along the c‐axis of a unit cell. The disentangled state is maintained in the melt over a period of time, invoking implications in polymer rheology. This approach is applicable to polymers in general. The homogeneous fully sintered UHMW‐PE, obtained for the first time, shows a considerable decrease in oxygen permeability, and increase in toughness and fatigue resistance. Such homogeneous products of UHMW‐PE are of beneficial in highly demanding applications, especially in knee‐prosthesis, where the polymer is used as an inlay between the human bone and a metal or ceramic part, which slides against the polyethylene component during normal gait.

Phase diagram for the extended chain crystals.

magnified image

Phase diagram for the extended chain crystals.
Effect of Copolymer Composition on the Dynamic Mechanical and Thermal Behaviour of Butyl Acrylate‐Acrylonitrile Copolymers
Authors: Suresh Kattimuttathu I. , Sitaramam Bhamidipalli S. , Raju Kothapally V. S. N.
Published: December 2003

This article reports data on the dynamic mechanical and thermal behaviour of butyl acrylate‐acrylonitrile copolymers and their variation with copolymer composition. The copolymers were prepared by emulsion polymerisation techniques, using potassium peroxodisulfate initiator at 80 ± 2 °C. Films were prepared from the latex by casting and analysed by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). For copolymer with 0.7 weight fraction of butyl acrylate the dynamic mechanical behaviour was identical to the synthetic rubber NBR (acrylonitrile‐butadiene rubber), such that the storage modulus shows a rapid decay with increasing temperature. The damping characteristics, as indicated by the tan δ value, increased as the weight fraction of butyl acrylate in the copolymer increased. The dynamic mechanical data has been analysed with the WLF‐Equation to study the time‐temperature relationship. The dynamic mechanical properties and glass transition data point to the formation of a copolymer, whose properties vary with acrylonitrile content. Thermogravimetric analysis revealed that weight loss occurring at a particular temperature decreases, along with the decomposition rate, with increase in acrylonitrile content. The activation energy (Ea) for the decomposition was calculated using the Coats & Redfern equation. When temperatures for 10% copolymer decomposition are compared from TGA data, the acrylonitrile rich copolymer starts decomposing at a lower temperature, but the rate of decomposition is slower and yields higher char yields.

Effect of copolymer composition on the variation of tan δ (max) at a measuring frequency of 1 Hz.

magnified image

Effect of copolymer composition on the variation of tan δ (max) at a measuring frequency of 1 Hz.
Generalized approximation spaces and applications
Authors: Almira Jose Maria , Luther Uwe
Published: December 2003

In the paper we generalize the theory of classical approximation spaces to a much wider class of spaces which are defined with the help of best approximation errors. We also give some applications. For example, we show that generalized approximation spaces can be used to find natural (in some sense) domains of definition of unbounded operators. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Asymptotic completeness for functions of the Laplacian perturbed by potentials and obstacles
Authors: Giere Eckhard
Published: December 2003

In this paper we show with scattering theoretical methods the absence of the singular continuous spectrum for operators that are perturbations of functions of the Laplacian. We extend the semigroup criteria developed in [9] and apply the result to the case of the fractional Laplacian (−Δ)α/2 where α ∈ (0, 2). We prove weighted Lp estimates for the semigroups generated by H0 = (−Δ)α/2 and H0 + V . These estimates are used for the verification of the semigroup criteria. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Graded rings and equivariant sheaves on toric varieties
Authors: Perling Markus
Published: December 2003

In this note we derive a formalism for describing equivariant sheaves over toric varieties. This formalism is a generalization of a correspondence due to Klyachko, which states that equivariant vector bundles on toric varieties are equivalent to certain sets of filtrations of vector spaces. We systematically construct the theory from the point of view of graded ring theory and this way we clarify earlier constructions of Kaneyama and Klyachko. We also connect the formalism to the theory of fine‐graded modules over Cox' homogeneous coordinate ring of a toric variety. As an application we construct minimal resolutions of equivariant vector bundles of rank two on toric surfaces. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Absolute continuity of autophage measures on finite‐dimensional vector spaces
Authors: Raja C. R. E.
Published: December 2003

We consider a class of measures called autophage which was introduced and studied by Szekely for measures on the real line. We show that the autophage measures on finite‐dimensional vector spaces over real or Qp are infinitely divisible without nontrivial idempotent factors and are absolutely continuous with bounded continuous density. We also show that certain semistable measures on such vector spaces are absolutely continuous. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polynomial growth solutions of Sturm‐Liouville equations on a half‐line and their zero distribution
Authors: Shin Chang Eon , Tovbis Alexander , Zayed Ahmed I.
Published: December 2003

For α ∈ [0, 2π], consider the Sturm‐Liouville equation on the half line

y″(x) + (λ − q(x))y(x) = 0,  0 ≤ x < ∞,

with

y(0) = sinα,  y′(0) = −cosα.

For each λ > 0, denote by ϕ(x, λ) the solution of the above initial‐value problem. It is known that the condition xq(x) ∈ L1(ℝ+) is sufficient for ϕ(x, λ) to be uniformly bounded by a linear function in x for all x, λ ≥ 0; however, this condition is not necessary as the Bessel differential equation demonstrates. In this paper we extend this result to the borderline case in which q(x) = O(1/x2) as x → ∞. We show that if q(x) is continuously differentiable and q(x) = O(1/x2) as x → ∞, that is, xq(x) may not be integrable on ℝ+, then there exists a polynomial p(x) such that

|ϕ(x, λ)| ≤ p(x)  for any  x ∈ [0,∞) and λ ∈ [0,∞).

As a particular example, we consider the perturbed Bessel equation

where ν ∈ ℝ and h(x) = o(1/x2) as x → ∞. The technique, developed in the paper, allows us to find upper and lower bounds on the distance between consecutive zeroes xn, xn+1 of the solution v(x) of the perturbed Bessel equation, as well as the asymptotics of xn+1 − xn as n → ∞. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the Helical Backbone in the Behavior of a Simple Model for Dimeric Coiled‐Coil Proteins
Authors: Prieto Lidia , Rey Antonio
Published: December 2003

Using computer simulations as a tool for thought experiments, we investigate the influence of the helical backbone geometry in the association process and the final structures of a simple model which mimics parallel, two‐stranded coiled‐coil proteins. We define three types of helices: two of them have straight helical axes and 3.5 or 3.6 residues per helical turn; the third type presents a coiled helical axis, according to the canonical scheme defined by Crick. By using a Monte Carlo simulation algorithm, we observe that the three models exhibit different transition temperatures for the formation of the dimeric structure from two independent peptides, and a different behavior concerning the appearance of out‐of‐register structures. The energy minimized dimer structures present strong deviations from the correct association for straight helices with 3.6 residues/turn, especially for long peptides, deviations which are absent for the other two types when only the burial of hydrophobic residues is considered. A careful analysis of the energies for the out‐of‐register configurations and the contact maps reveals also differences between dimers resulting from the model with Crick parameterization and with 3.5 residues/turn. The results presented in this paper may be relevant for the design of simple models which use rigid α‐helices built from predicted elements of secondary structure.

Top views of the helical models used in this work.

image

Top views of the helical models used in this work.
Inverse problem for a perturbed stratified strip in two dimensions
Authors: Cristofol Michel , Gaitan Patricia
Published: December 2003

We consider the divergence form elliptic operator A=−∇x,z·(c2(x,z) ∇x,z) in the strip Ω=ℝ× [0,H]. The velocity c(x,z) describes the multistratification of Ω: a horizontal stratification with a compact perturbation K, the velocity in K is a L∞(K) function. We suppose that the position of the perturbation is known and we prove uniqueness for identification of the perturbation from one generalized eigenfunction pattern in the neighbourhood of K. Copyright © 2004 John Wiley & Sons, Ltd.
Sufficient conditions of non‐uniqueness for the Coulomb friction problem
Authors: Hassani Riad , Hild Patrick , Ionescu Ioan
Published: December 2003

We consider the Signorini problem with Coulomb friction in elasticity. Sufficient conditions of non‐uniqueness are obtained for the continuous model. These conditions are linked to the existence of real eigenvalues of an operator in a Hilbert space. We prove that, under appropriate conditions, real eigenvalues exist for a non‐local Coulomb friction model. Finite element approximation of the eigenvalue problem is considered and numerical experiments are performed. Copyright © 2003 John Wiley & Sons, Ltd.
Galerkin method for optimal control of second‐order evolution equations
Authors: Dȩbińska‐Nagórska Anna , Just Andrzej , Stempień Zdzisaw
Published: December 2003

This paper presents the Galerkin approximation of the optimization problem of a system governed by non‐linear second‐order evolution equation where a non‐linear operator depends on derivative of the state of the system. The control is acting on a non‐linear equation. After giving some results on the existence of optimal control we shall prove the existence of the weak and strong condensation points of a set of solutions of the approximate optimization problems. Each of these points is a solution of the initial optimization problem. Finally we shall give a simple example using the obtained results. Copyright © 2004 John Wiley & Sons, Ltd.
Capacitation of mammalian spermatozoa in vivo, with a specific focus on events in the fallopian tubes
Authors: Hunter R.H.F. , Rodriguez‐Martinez H.
Published: December 2003

This essay argues strongly that for those sperm cells involved in fertilisation, the process of capacitation represents an active and specific coordination within succeeding regions of the female tract and one whose completion is synchronised with the events of ovulation. Observations on the time‐course of capacitation when spermatozoa are first exposed to the uterus and then progress to the Fallopian tubes indicate a synergistic influence of these adjoining portions of the female tract on the rate of capacitation. Three concepts on the control of capacitation are introduced to emphasise the importance of integration in vivo, namely that (1) completion of capacitation is a peri‐ovulatory event, (2) suppression of completion of capacitation is an essential storage strategy during a long pre‐ovulatory interval, and (3) the process of capacitation comes under the influence of local and systemic ovarian control mechanisms, especially the secretion of progesterone from Graafian follicles soon to ovulate. The last would act to coordinate the final maturation and meeting of male and female gametes. Despite the preceding points, the requirement for such integrated in vivo programming of sperm cell maturation can clearly be overridden in systems of culture. The most reasonable interpretation here would be that a microdrop of culture medium containing eggs, follicular cells and components of follicular fluid would to a considerable extent represent a post‐ovulatory environment. Within such a preparation, there would be leaching of the sperm surface among the relatively vast and heterogeneous population of cells, and a proportion of spermatozoa could then respond to ‘post‐ovulatory signals’, not least to molecular influences of the zona pellucida and vitelline products for completion of capacitation. Nonetheless, a physiologically meaningful interpretation of capacitation calls for a stepwise analysis of the dynamic interactions between sperm cell and female tract at successive stages between the uterus and ampullary‐isthmic junction. Mol. Reprod. Dev. 67:243–250, 2004. © 2004 Wiley‐Liss, Inc.
Activity of an enzyme converting single‐chain tissue‐type plasminogen activator to the two‐chain form in preovulatory human follicular fluid
Authors: Ohnishi Junji , Yokota Jyunko , Rajapakse R.G.S.C. , Ohnishi Eriko , Kudo Takayuki , Wada Shin‐Ichiro , Takahashi Takayuki
Published: December 2003

The biological role of the tissue‐type plasminogen activator (tPA)/plasmin system has long been implicated in ovarian function. We have recently shown that the follicular fluid of human ovaries contains an α2‐macroglobulin/protease complex capable of converting single‐chain (sc) tPA to the two‐chain (tc) enzyme tPA, suggesting the occurrence of its corresponding enzyme in a free form in the fluid. The aim of the current study is therefore to gain further information about the putative sctPA‐converting enzyme present in follicular fluid. Incubation of human recombinant sctPA with the fluid brought about the production of tctPA. It was also demonstrated that tctPA production resulted in the activation of endogenous fluid plasminogen. Production of tctPA and plasmin both was strongly inhibited by aprotinin, suggesting that the enzyme is a serine protease. The sctPA‐converting enzyme was partially purified from the fluid by column chromatographies. The enzyme preferably hydrolyzed synthetic peptide substrates containing arginine at the P1 position. The enzyme preparation had a protease inhibitor profile similar to that observed with the crude fluid sample. These results clearly demonstrated that follicular fluid contains an enzyme capable of efficiently converting sctPA to tctPA. Discovery of this sctPA‐converting enzyme strongly suggests that the tPA/plasmin system in the preovulatory follicle of human ovaries is operated through the proteolytic conversion of sctPA to tctPA rather than being regulated by a fibrin‐dependent mechanism. Mol. Reprod. Dev. 67:178–185, 2004. © 2004 Wiley‐Liss, Inc.
Mitochondrial DNA heteroplasmy in calves cloned by using adult somatic cell
Authors: Han Zhi‐Ming , Chen Da‐Yuan , Li Jin‐Song , Sun Qing‐Yuan , Wan Qiu‐Hong , Kou Zhao‐Hui , Rao Gang , Lei Lei , Liu Zhong‐Hua , Fang Sheng‐Guo
Published: December 2003

Adult somatic cell cloned calves were produced by somatic cell nuclear transfer prepared by fusion of cultured ear fibroblast from a Holstein cow into enucleated oocytes of Luxi Yellow cow. In order to determinate the source of mitochondrial DNA of cloned calves, we designed the breed‐specific PCR primers by aligning the known D‐loop sequences of Bos taurus and analyzed the displacement loop sequences of five live cloned calves by breed‐specific primers PCR. The results demonstrated that mtDNA originated from Holstein breed and that from Luxi breed co‐exist in all five live calves. Mol. Reprod. Dev. 67:207–214, 2004. © 2004 Wiley‐Liss, Inc.
Intracarpal steroid injection is safe and effective for short‐term management of carpal tunnel syndrome
Authors: Armstrong Timothy , Devor William , Borschel Laura , Contreras Richard
Published: December 2003

A double‐blinded placebo‐controlled trial was performed to evaluate the use of steroid injections beneath the transverse carpal ligament in the treatment of carpal tunnel syndrome (CTS) refractory to nonsurgical therapy. Forty‐three patients received 6 mg betamethasone and lidocaine and 38 patients received 1 ml saline placebo and lidocaine. The primary outcome measure was satisfaction with symptom relief. Thirty patients (70%) in the steroid‐treated group were satisfied or highly satisfied compared with 13 (34%) of placebo‐treated patients (P < 0.001). Patients receiving steroids also showed significant improvement in median nerve conduction parameters and scores on validated symptom/function questionnaires. Forty‐six patients were treated with serial injections for recurrent CTS symptoms. After 18 months, 17 patients reported adequate symptom relief with steroid injection, and 18 patients with unsatisfactory symptom relief were referred for carpal tunnel release surgery. We conclude that although steroid injections are safe and effective for temporary relief of CTS, most patients will eventually require surgery for long‐term control of their symptoms. Muscle Nerve 29: 82–88, 2003
Enhanced neuromuscular transmission efficacy in overloaded rat plantaris muscle
Authors: Argaw Anteneh , Desaulniers Patrice , Gardiner Phillip F.
Published: December 2003

To better understand the effect of muscle hypertrophy on the physiological properties of transmitter release, we investigated neuromuscular transmission (NMT) efficacy in overloaded rat plantaris muscle in situ. In the overload group, following bilateral tenotomy of plantaris synergists, rats were confined to wheel‐cages. Age‐matched rats in the control group were confined to plastic cages. During the terminal experiment, muscle action potentials were blocked using μ‐conotoxin, and full‐sized endplate potentials (EPPs) were recorded at 25, 50, and 75 HZ to determine their amplitude rundown. Quantal contents for the control and overload groups were 37.0 and 74.3, respectively (P <0.01). There was a significant group difference in EPP amplitude rundown at all frequencies examined, with increased rundown occurring in the overload group (P < 0.01). Cumulative quantal release was 139% and 153% higher in the overload group at 25 and 50 HZ, respectively (P < 0.05). Together, these data suggest the safety factor for NMT is increased by neuromuscular overload. Furthermore, these findings support and supplement previously reported activity‐dependent improvements in NMT efficacy that are probably mediated via presynaptic adaptations. Muscle Nerve 29: 89–96, 2004
Assessment of pelvic organ descent by use of functional cine‐MRI: Which reference line should be used?
Authors: Lienemann Andreas , Sprenger Dorothée , Janßen Udo , Grosch Eva , Pellengahr Christoph , Anthuber Christoph
Published: December 2003

Background and Aims

So far there is no agreement between clinical and radiological measurements and reference points for the quantification of pelvic organ descent in women. The aim of this study was to find out which of three reference lines on functional cine‐magnetic resonance imaging (MRI) correlates best with the respective clinical diagnoses.

Methods

We retrospectively evaluated the functional cine‐MRI studies of 41 asymptomatic volunteers. Our golden standard was the results of the clinical examination using the International Continence Society (ICS)‐score. On MRI, we measured the distance of the bladder‐neck, distal edge of cervix/posterior fornix, and the most ventrocaudal point of the ventral rectal wall, respectively, to the pubococcygeal line (PCL), the horizontal tangent of the inferior rim of the pubic bone, and the line drawn through the long axis of the pubic bone. The results were correlated with the respective clinical findings using descriptive analysis alone.

Results

The volunteers either showed a Stage 0 (16 cases), Stage I (12 cases), or a Stage II (13 cases) organ descent on clinical examination with 10 women (24.4%) having a pathological ICS‐score in the anterior, 15 women (36.1%) in the superior, and 4 women (9.8%) in the posterior compartment. On functional MRI the best correlation with the clinical results was achieved using the PCL for the anterior compartment (22.0%), the PCL with an offset of +3 cm for the superior (36.6%), and the hymenal line (HL) for the posterior compartment (9.8%).

Conclusions

Organ descent on functional cine‐MRI cannot be described using only one reference line. In order to optimize clinical exploitation of functional MRI of the pelvic floor a consensus regarding imaging protocols and evaluation criteria should be aimed for. Neurourol. Urodynam. 23:33–37, 2004. © 2003 Wiley‐Liss, Inc.
Design, analysis, and synthesis of generalized single step single solve and optimal algorithms for structural dynamics
Authors: Zhou X. , Tamma K. K.
Published: December 2003

The primary objectives of the present exposition are to: (i) provide a generalized unified mathematical framework and setting leading to the unique design of computational algorithms for structural dynamic problems encompassing the broad scope of linear multi‐step (LMS) methods and within the limitation of the Dahlquist barrier theorem (Reference [3], G. Dahlquist, BIT 1963; 3: 27), and also leading to new designs of numerically dissipative methods with optimal algorithmic attributes that cannot be obtained employing existing frameworks in the literature, (ii) provide a meaningful characterization of various numerical dissipative/non‐dissipative time integration algorithms both new and existing in the literature based on the overshoot behavior of algorithms leading to the notion of algorithms by design, (iii) provide design guidelines on selection of algorithms for structural dynamic analysis within the scope of LMS methods. For structural dynamics problems, first the so‐called linear multi‐step methods (LMS) are proven to be spectrally identical to a newly developed family of generalized single step single solve (GSSSS) algorithms. The design, synthesis and analysis of the unified framework of computational algorithms based on the overshooting behavior, and additional algorithmic properties such as second‐order accuracy, and unconditional stability with numerical dissipative features yields three sub‐classes of practical computational algorithms: (i) zero‐order displacement and velocity overshoot (U0‐V0) algorithms; (ii) zero‐order displacement and first‐order velocity overshoot (U0‐V1) algorithms; and (iii) first‐order displacement and zero‐order velocity overshoot (U1‐V0) algorithms (the remainder involving high‐orders of overshooting behavior are not considered to be competitive from practical considerations). Within each sub‐class of algorithms, further distinction is made between the design leading to optimal numerical dissipative and dispersive algorithms, the continuous acceleration algorithms and the discontinuous acceleration algorithms that are subsets, and correspond to the designed placement of the spurious root at the low‐frequency limit or the high‐frequency limit, respectively. The conclusion and design guidelines demonstrating that the U0‐V1 algorithms are only suitable for given initial velocity problems, the U1‐V0 algorithms are only suitable for given initial displacement problems, and the U0‐V0 algorithms are ideal for either or both cases of given initial displacement and initial velocity problems are finally drawn. For the first time, the design leading to optimal algorithms in the context of a generalized single step single solve framework and within the limitation of the Dahlquist barrier that maintains second‐order accuracy and unconditional stability with/without numerically dissipative features is described for structural dynamics computations; thereby, providing closure to the class of LMS methods. Copyright © 2003 John Wiley & Sons, Ltd.
Finite element of slender beams in finite transformations: a geometrically exact approach
Authors: Boyer Frédéric , Primault Dominique
Published: December 2003

This article is devoted to the modelling of thin beams undergoing finite deformations essentially due to bending and torsion and to their numerical resolution by the finite element method. The solution proposed here differs from the approaches usually implemented to treat thin beams, as it can be qualified as ‘geometrically exact’. Two numerical models are proposed. The first one is a non‐linear Euler–Bernoulli model while the second one is a non‐linear Rayleigh model. The finite element method is tested on several numerical examples in statics and dynamics, and validated through comparison with analytical solutions, experimental observations and the geometrically exact approach of the Reissner beam theory initiated by Simo. The numerical result shows that this approach is a good alternative to the modelling of non‐linear beams, especially in statics. Copyright © 2003 John Wiley & Sons, Ltd.
An adaptive penalty scheme for genetic algorithms in structural optimization
Authors: Lemonge Afonso C. C. , Barbosa Helio J. C.
Published: December 2003

A parameter‐less adaptive penalty scheme for genetic algorithms applied to constrained optimization problems is proposed. Using feedback from the evolutionary process the procedure automatically defines a penalty parameter for each constraint. The user is thus relieved from the burden of having to determine sensitive parameter(s) when dealing with every new constrained optimization problem. The procedure is shown to be effective and robust when applied to test problems from the evolutionary computation literature as well as several optimization problems from the structural engineering literature. Copyright © 2003 John Wiley & Sons, Ltd.
An ellipsoidal particle–finite element method for hypervelocity impact simulation
Authors: Shivarama Ravishankar , Fahrenthold Eric P.
Published: December 2003

A number of coupled particle–element and hybrid particle–element methods have been developed for the simulation of hypervelocity impact problems to avoid certain disadvantages associated with the use of pure continuum‐based or pure particle‐based methods. To date these methods have employed spherical particles. In recent work a hybrid formulation has been extended to the ellipsoidal particle case. A model formulation approach based on Lagrange's equations, with particle entropies serving as generalized coordinates, avoids the angular momentum conservation problems which have been reported with ellipsoidal smooth particle hydrodynamics models. Copyright © 2003 John Wiley & Sons, Ltd.
Immunohistochemical analysis of the IL‐6 family of cytokines and their receptors in benign, hyperplasic, and malignant human prostate
Authors: Royuela Mar , Ricote Monica , Parsons Melanie S , García‐Tuñón Ignacio , Paniagua Ricardo , De Miguel Maria P
Published: December 2003

Interleukin‐6 (IL‐6) and its receptor have been implicated in prostate cancer progression. Because other members of the IL‐6 family such as leukaemia inhibitory factor (LIF) and oncostatin M (OSM) share gp130, the signal transduction subunit of their receptors, interpretation of the data without considering the expression of these cytokines and their specific receptor subunits could be misleading. The immunohistochemical pattern of the IL‐6 family and their receptor subunits in normal prostate, benign prostatic hyperplasia (BPH), and prostatic carcinoma (PC) was investigated. In normal prostates, gp130 and OSMRα were detected exclusively in the stroma and LIFRβ was very scarce. While IL‐6 was scarcely immunolocalized to the basal cells of the epithelium, OSM was detected in the stroma and LIF in both the epithelium and the stroma. This suggests an autocrine role for this family of cytokines in the stroma of normal prostates. In BPH, gp130 and OSMRα were detected both in the epithelium and in the stroma, whereas LIFRβ was localized only to the epithelium. IL‐6 localized preferentially to the epithelium, OSM to the stroma, and LIF to both compartments. Therefore, in addition to the autocrine role in the stroma, IL‐6 and OSM may play a paracrine role from the stroma to the epithelium in BPH. In PC, gp130 and OSMRα were detected both in the epithelium and in the stroma, increasing with rising Gleason grade, whereas LIFRβ was localized exclusively to the epithelium of low Gleason grade carcinomas. IL‐6, LIF, and OSM localized in all cell types, with immunostaining increasing with Gleason grade. These data suggest an autocrine role for these cytokines in the epithelial cells of PC. The distinct pattern of expression of LIFRβ exclusively in low Gleason grade carcinomas makes LIFRβ a candidate for malignancy diagnosis. The role of OSM mainly in high Gleason grade carcinomas makes OSM a putative target for prostate cancer therapy. Copyright © 2003 John Wiley & Sons, Ltd.
Differential Eµ enhancer activity and expression of BOB.1/OBF.1, Oct2, PU.1, and immunoglobulin in reactive B‐cell populations, B‐cell non‐Hodgkin lymphomas, and Hodgkin lymphomas
Authors: Loddenkemper Christoph , Anagnostopoulos Ioannis , Hummel Michael , Jöhrens‐Leder Korinna , Foss Hans‐Dieter , Jundt Franziska , Wirth Thomas , Dörken Bernd , Stein Harald
Published: December 2003

It has previously been demonstrated that in cultured and in situ tumour cells of classical Hodgkin lymphoma (cHL), the immunoglobulin (Ig) promoter is inactive and its transcription factors Oct2 and/or BOB.1/OBF.1 are down‐regulated. In this study, the analysis of these transcription factors has been extended to a broad spectrum of B‐cell malignancies and the findings have been related to the situation in normal B‐cells of various differentiation stages and to the expression of Ig. Furthermore, an additional Ig transcription factor, PU.1, recently described to be absent from cHL, and a further regulatory element of the Ig gene, the intronic Eµ enhancer, have been studied. BOB.1/OBF.1 and Oct2 were present in all B‐cells expressing Ig, whereas PU.1 proved to be absent from late B‐cell differentiation stages and from a subset of germinal centre B‐cells. Interestingly, there were several normal (eg germinal centre centroblasts and monocytoid B‐cells) and malignant B‐cell populations (eg a proportion of diffuse large B‐cell lymphomas, DLBCLs) that were Ig‐negative, despite their BOB.1/OBF.1 and Oct2 expression. This study further shows that absence of PU.1 alone, as well as inactivation of the intronic Eµ enhancer, is not sufficient to down‐regulate Ig transcription. Taken together, the simultaneous absence of PU.1, Oct2, and/or BOB.1/OBF.1 is unique to Hodgkin and Reed–Sternberg (HRS) cells and cannot be detected in normal B‐cell subsets or B‐cell non‐Hodgkin lymphomas (B‐NHLs). This supports the concept that the down‐regulation of Ig in cHL does not reflect a physiological situation, but a defect probably closely linked to the pathogenesis of cHL. Copyright © 2004 John Wiley & Sons, Ltd.
Differential expression of the calcium sensing receptor and combined loss of chromosomes 1q and 11q in parathyroid carcinoma
Authors: Haven Carola J , van Puijenbroek Marjo , Karperien Marcel , Fleuren Gert‐Jan , Morreau Hans
Published: December 2003

Malignant transformation of parathyroid tumours is rare. Nevertheless, this small subset of malignant tumours often creates diagnostic and therapeutic problems. In this work, the morphological characteristics of 26 primary parathyroid carcinomas and seven metastases have been studied. Furthermore, immunohistochemical expression profiles for the calcium sensing receptor (CASR), cyclin D1 (CCND1), and Ki‐67 were determined for parathyroid carcinomas and compared with adenomas and hyperplasias using a tissue microarray. Loss of heterozygosity (LOH) of the chromosome 1q region containing the HRPT2 gene and chromosome 11q (MEN1) was determined in the carcinomas. In contrast to the adenomas and hyperplasias, 31% of carcinomas demonstrated down‐regulation of CASR. A significant correlation was found between CASR expression and the Ki‐67 proliferation index. Chromosome 1q and chromosome 11q LOH were found in 12 of 22 (55%) and 11 of 22 (50%) carcinomas tested, respectively. Combined 1q and 11q LOH was seen in 8 of 22 (36%) carcinomas, in contrast to the low percentage of LOH reported in both regions in adenomas. In conclusion, this study demonstrates that combined 1q and 11q LOH in parathyroid tumours is suggestive of malignant behaviour. Strong down‐regulation of the CASR protein is seen in a proportion of parathyroid carcinomas with a high proliferation index. Copyright © 2004 John Wiley & Sons, Ltd.