bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclosporine‐A delays the end‐plate degeneration in denerved rat muscles
Authors: Rodella Luigi , Bonaspetti Giovanni , Rezzani Rita , Borsani Elisa , Fenu Riccardo , Pazzaglia Ugo , Bianchi Rossella 
Published: October 2002

AbstractWhen an adult skeletal muscle is denervated, its end‐plates degenerate and their acethylcholinesterase (AChE) activity gradually decreases. However, if the proximal segment of the nerve is sutured to the distal segment, or if the nerve is implanted in a previous denerved muscle the axons regenerate and reconstitute new end‐plates over a variable period. This period depends on the time passed between the nerve cutting and the reimplantation suggesting that the degenerative processes are closely correlated to regeneration. It has been shown that cyclosporine‐A (CsA) is useful in nerve regeneration but their role in nerve degeneration is not well understand. We evaluated, using AChE histochemistry, the effects of CsA, on the degeneration of the end‐plates in an experimental model of gastrocnemius muscle denervation in the rat. CsA at a dose of 15 mg/kg/day did not cause any quantitative or qualitative alterations in the end‐plates on normal rat muscles. Moreover, our findings showed that CsA reduced the end‐plate degeneration and loss in the denerved rat muscles.
Tissue xanthine oxidase activity and nitric oxide levels after spinal cord ischemia/reperfusion injury in rabbits: comparison of caffeic acid phenethyl ester (CAPE) and methylprednisolone
Authors: Şahin Şemsettin , Söğüt Sadık , Özyurt Hüseyin , Uz Efkan , İlhan Atilla , Akyol Ömer 
Published: October 2002

AbstractCaffeic acid phenethyl ester exhibits antioxidant properties. This experimental study was designed to determine the effect of CAPE on nitric NO level and XO activity after reperfusion injury of spinal cord. New Zealand white rabbits were undergone aortic occlusion. CAPE, methylprednisolone or saline were injected intraperitoneally before surgical intervention. Animals were subjected to 21 min of crossclamp time. At the end of occlusion time, the clamps were removed and restoration of the blood flow was verified visually. Animals in sham group underwent a surgical procedure similar to the other groups but the aorta was not occluded. Spinal cord specimens were obtained to determine the tissue levels of NO and XO activity.Both XO activity and NO level in ischemia group were significantly higher than those of sham group (p = 0.0005 and 0.0003, respectively). MP and CAPE had no effect on XO activity after reperfusion. These two agents decreased NO levels nearly to that of sham group after reperfusion. There were no differences between MP and CAPE on reducing NO level. These results suggest that rabbits with ischemia‐reperfusion injury in spinal cord have increased cord concentrations of nitrite and nitrate that are indicative of endogenous overproduction of NO. CAPE may be regarded as an agent that protects spinal cord from ischemia‐reperfusion injury.
Mechanisms of bicuculline‐induced hypersensitivity of medullary dorsal horn neurons in rats
Authors: Nam Soon H. , Seo Jeong P. , J. Kim Young , Kim Hyun J. , Ju Jin S. , Ahn Dong K. 
Published: October 2002

AbstractThe purpose of the present study was to examine the responses of medullary dorsal horn neurons to microiontophoretic application of the γ‐aminobutyric acid (GABA)A receptor antagonist, bicuculline. The mechanisms of bicuculline‐induced hypersensitivity were also investigated. Extracellular recordings were made with the central barrel of a seven‐barrel micropipette. Microiontophoretic application of bicuculline greatly increased N‐methyl‐D‐aspartic acid (NMDA)‐evoked responses of medullary dorsal horn neurons. Bicuculline also increased the responses to both noxious pinching and brushing of cutaneous receptor fields. Both NMDA and non‐NMDA receptor antagonists blocked the facilitated responses to iontophoretic application of bicuculline. However, the mu and delta receptor agonists did not block the hypersensitivity produced by iontophoretic application of bicuculline. These results suggest that GABA modulates the synaptic transmission of both noxious and non‐noxious information in the trigeminal spinal sensory nuclei. Bicuculline‐induced hypersensitivity seems to be mediated by excitatory amino acid receptors and provides a mechanism for neuropathic pain.
Structures of X 34‐nylons in chain‐folded lamellae and gel‐spun fibers
Authors: Ehrenstein Moritz , Sikorski Pawel , Atkins Edward , Smith Paul 
Published: October 2002

AbstractStructural studies and morphological features of a new family of linear, aliphatic even–even, X 34‐nylons, with X = 2, 4, 6, 8, 10, and 12, are investigated with X‐ray diffraction and electron microscopy. Solution‐grown crystals were obtained by isothermal crystallization from N,N‐dimethylformamide solutions. The thickness of lamellar‐like crystals was orders of magnitude less than the chain lengths of the polymer samples used, implying that the chains fold to form chain‐folded lamellae. The results bear a close resemblance, with the noticeable exception of 2 34‐nylon, to those reported for nylon 6 6 and other even–even nylon chain‐folded lamellar crystals. The basic structure of the straight‐stem lamellar core is similar to that of the classic nylon 6 6 triclinic α structure, and the chains tilt ≈42° relative to the lamellar normal. In the case of 2 34‐nylon, the structure resembles the 2 Y nylon series, and the chain tilt angle reduces to 36.6°. These combined results suggest that, even with a relatively low frequency of amide units along the backbone of these molecules, hydrogen bonding is still the dominant element in controlling the behavior, structure, and properties of these polymers. In addition, gels were prepared in concentrated sulfuric acid, and gel‐spun fibers were studied using X‐ray diffraction. The data are interpreted in terms of a modified nylon triclinic α structure that bears a resemblance to the structure of even–even nylons at elevated temperatures. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2685–2692, 2002
Components of microstrain in polyethylene
Authors: Brown Norman , Rabinowitz Stephen 
Published: October 2002

AbstractTensile microstrain was measured in high‐density polyethylene with a precision of 2 × 10−7 for strains up to 10−4 in the temperature range of 17–28 °C over a range of strain rates. The total strain was partitioned into three of the following components: (1) elastic, (2) amorphous, and (3) dislocation. Also, their respective dependence on stress was determined. Measurements of the area of the hysteresis loops gave the energy loss per cycle from which the frictional stress on the amorphous flow and the dislocations was determined. Although the amorphous strain originated at zero stress and was dependent on the temperature and strain rate, the dislocation motion was activated above acritical stress and independent of temperature and strain rate within the scope of these experiments. The viscosity of the amorphous flow was determined. The effect of 5 Mrd γ irradiation on the micro‐deformation behavior was not appreciable. About 80 Mrd reduced the amorphous flow by about 30% and increased the stress to activate the motions of the dislocations. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2693–2701, 2002
Effect of selected structural parameters of styrene–butadiene block copolymers on their compatibilization efficiency in polystyrene/polybutadiene blends
Authors: Horák Z. , Hlavatá D. , Hromádková J. , Kotek J. , Hašová V. , Mikešová J. , Pleska A. 
Published: October 2002

AbstractThe effects of the block length and block number of linear styrene–butadiene (S–B) block copolymers on their compatibilization efficiency in blending polystyrene with polybutadiene were studied. For this purpose, two sets of model S–B copolymers and both homopolymers were prepared by anionic polymerization. Diblocks, triblocks, or pentablocks of S–B copolymers were blended with these homopolymers, and the structures and some end‐use properties of the blends were determined. The supramolecular structure (determined by small‐angle X‐ray scattering), morphology (determined by transmission and scanning electron microscopy), and stress‐transfer characteristics (impact and tensile strengths) of the blends were chosen as criteria for the compatibilization efficiency of the copolymers used. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2612–2623, 2002
Direct formation of form I poly(1‐butene) single crystals from melt crystallization in ultrathin films
Authors: Zhang Bin , Yang Decai , Yan Shouke 
Published: October 2002

AbstractThe morphologies and crystalline structures of melt‐crystallized ultrathin isotactic poly(1‐butene) films have been studied with transmission electron microscopy and electron diffraction. It is demonstrated that a bypass of form II crystallization can be achieved with an increase in its crystallization temperature. Electron microscopy observations show that melt‐grown isotactic poly(1‐butene) single crystals have a well‐shaped hexagonal form, whereas form I crystals converted from form II display the morphologies of their tetragonal precursors. Electron diffraction results indicate that, instead of the twinned hexagonal pattern of the converted form I crystal, the directly formed form I single crystals exhibit an untwinned hexagonal pattern. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2641–2645, 2002
Crystalline structure and morphology of biaxially oriented polyamide‐11 films
Authors: Rhee Sangkeun , White James L. 
Published: October 2002

AbstractThe effect of the uniaxial and biaxial stretching and subsequent solution annealing of extrusion‐cast polyamide‐11 films on the crystalline structure and morphology was investigated with differential scanning calorimetry, wide‐angle X‐ray diffraction (WAXD), Fourier transform infrared spectroscopy, and small‐angle X‐ray scattering (SAXS). The extrusion‐cast polyamide‐11 films exhibited elevations in the glass‐transition and cold‐crystallization temperatures with a constant crystallinity and a constant melting point during aging under room conditions (20–26 °C and 20–31% relative humidity). WAXD and SAXS suggested that chain‐folded lamellae of coexisting α‐ and β‐crystals existed in all the stretched polyamide‐11 films. WAXD pole figures indicated that hydrogen bonds in the hydrogen‐bonded sheets of these two crystalline forms apparently formed between antiparallel chain molecules. The unit cell parameters [a = 9.52 Å, b = 5.35 Å, c = 14.90 Å (chain axis), α = 48.5°, β = 90°, and γ = 74.7° for a triclinic α form and a = 9.52 Å, b = 14.90 Å (chain axis), c = 4.00 Å, α = 90°, β = 67.5°, and γ = 90° for a monoclinic β form] for polyamide‐11 crystals were proposed according to the results of this study and the results of previous investigators. The unit cell parameters of the stretched extrusion‐cast polyamide‐11 films varied, depending on the stretching conditions (the stretch temperature and stretch ratio). As the stretch temperature and stretch ratio were increased, the crystal became more similar to the form described previously and was accompanied by an increase in the long spacing of crystalline lamellae. Annealing the stretched films in a boiling 20% formic acid solution made slightly more perfected crystals. The hydrogen‐bonding α(010) + β(002) planes, which are nearly parallel to both amide group planes and zigzag methylene sequence planes of the biaxially stretched films were found to be parallel to the film surface. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2624–2640, 2002
Nonatomic solvent‐driven voronoi tessellation of proteins: An open tool to analyze protein folds
Authors: Angelov Borislav , Sadoc Jean‐François , Jullien Rémi , Soyer Alain , Mornon Jean‐Paul , Chomilier Jacques 
Published: October 2002

AbstractA three‐dimensional Voronoi tessellation of folded proteins is used to analyze geometrical and topological properties of a set of proteins. To each amino acid is associated a central point surrounded by a Voronoi cell. Voronoi cells describe the packing of the amino acids. Special attention is given to reproduction of the protein surface. Once the Voronoi cells are built, a lot of tools from geometrical analysis can be applied to investigate the protein structure; volume of cells, number of faces per cell, and number of sides per face are the usual signatures of the protein structure. A distinct difference between faces related to primary, secondary, and tertiary structures has been observed. Faces threaded by the main‐chain have on average more than six edges, whereas those related to helical packing of the amino acid chain have less than five edges. The faces on the protein surface have on average five edges within 1% error. The average number of faces on the protein surface for a given type of amino acid brings a new point of view in the characterization of the exposition to the solvent and the classification of amino acid as hydrophilic or hydrophobic. It may be a convenient tool for model validation. Proteins 2002;49:446–456. © 2002 Wiley‐Liss, Inc.
Data mining the protein data bank: Residue interactions
Authors: Oldfield T.J. 
Published: October 2002

AbstractThe protein databank contains a vast wealth of structural and functional information. The analysis of this macromolecular information has been the subject of considerable work in order to advance knowledge beyond the collection of molecular coordinates. This article presents a method that determines local structural information within proteins using mathematical data mining techniques. The mine program described returns many known configurations of residues such as the catalytic triad, metal binding sites and the N‐linked glycosylation site; as well as many other multiple residue interactions not previously categorized. Because mathematical constructs are used as targets, this method can identify new information not previously known, and also provide unbiased results of typical structure and their expected deviations. Because the results are defined mathematically, they cannot indicate the biological implications of the results. Therefore two support programs are described that provide insight into the biological context for the mine results. The first allows a weighted RMSD search between a template set of coordinates and a list of PDB files, and the second allows the labeling of a protein with the template results from mining to aid in the classification of this protein. Proteins 2002;49:510–528. © 2002 Wiley‐Liss, Inc.
Solution structure of the DNA‐binding domain of interleukin enhancer binding factor 1 (FOXK1a)
Authors: Liu Pei‐Phen , Chen Yen‐Chin , Li Ching , Hsieh Yu‐Huei , Chen Shu‐Wan , Chen Shu‐Huei , Jeng Wen‐Yih , Chuang Woei‐Jer 
Published: October 2002

AbstractInterleukin enhancer binding factor (ILF) binds to the interleukin‐2 (IL‐2) promoter and regulates IL‐2 gene expression. In this study, the 3D structure of the DNA‐binding domain of ILF was determined by multidimensional NMR spectroscopy. NMR structure analysis revealed that the DNA‐binding domain of ILF is a new member of the winged helix/forkhead family, and that its wing 2 contains an extra α‐helix. This is the first study to report the presence of a C‐terminal α‐helix in place of a typical wing 2 in a member of this family. This structural difference may be responsible for the different DNA‐binding specificity of ILF compared to other winged helix/forkhead proteins. Our deletion studies of the fragments of ILF also suggest that the C‐terminal region plays a regulatory role in DNA binding. Proteins 2002;49:543–553. © 2002 Wiley‐Liss, Inc.
Origins of protein denatured state compactness and hydrophobic clustering in aqueous urea: Inferences from nonpolar potentials of mean force
Authors: Shimizu Seishi , Chan Hue Sun 
Published: October 2002

AbstractFree energies of pairwise hydrophobic association are simulated in aqueous solutions of urea at concentrations ranging from 0–8 M. Consistent with the expectation that hydrophobic interactions are weakened by urea, the association of relatively large nonpolar solutes is destabilized by urea. However, the association of two small methane‐sized nonpolar solutes in water has the opposite tendency of being slightly strengthened by the addition of urea. Such size effects and the dependence of urea‐induced stability changes on the configuration of nonpolar solutes are not predicted by solvent accessible surface area approaches based on energetic parameters derived from bulk‐phase solubilities of model compounds. Thus, to understand hydrophobic interactions in proteins, it is not sufficient to rely solely on transfer experiment data that effectively characterize a single nonpolar solute in an aqueous environment but not the solvent‐mediated interactions among two or more nonpolar solutes. We find that the m‐values for the rate of change of two‐methane association free energy with respect to urea concentration is a dramatically nonmonotonic function of the spatial separation between the two methanes, with a distance‐dependent profile similar to the corresponding two‐methane heat capacity of association in pure water. Our results rationalize the persistence of residual hydrophobic contacts in some proteins at high urea concentrations and explain why the heat capacity signature (ΔCP) of a compact denatured state can be similar to ΔCP values calculated by assuming an open random‐coil‐like unfolded state. Proteins 2002;49:560–566. © 2002 Wiley‐Liss, Inc.
An intervention study to enhance girls' interest, self‐concept, and achievement in physics classes
Authors: Häussler Peter , Hoffmann Lore 
Published: October 2002

AbstractMany interest studies have shown the decline of students' interest in physics during secondary education, particularly among girls. Research into physics‐related interests of students suggests applying different measures to reduce or reverse that trend such as: (a) suggesting curricular changes that do justice to the specific interests and experiences of girls, (b) improving the ability of teachers to support girls in the development of a positive physics related self‐concept, and (c) changing to an organizational setting that gives girls a better chance to improve their self‐concept about physics. The purpose of this study was to examine whether these hypothetically effective measures lead to an improvement of the situation for girls when implemented in the physics classroom. The intervention took a whole school year of some 60 one‐hour lessons and comprised 12 experimental and 7 control classes of seventh graders (age about 13). Their immediate and long‐term achievements, as well as their change of interest in physics, their subjectively experienced competence, and their physics‐related self‐concept were assessed by written tests at various stages of the intervention. The intervention proved successful and significantly improved most of these indicators for girls (and boys) in the experimental group. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 870–888, 2002
Analysis of students' assessments in middle school curriculum materials: Aiming precisely at benchmarks and standards
Authors: Stern, Luli , Ahlgren Andrew 
Published: October 2002

AbstractAssessment influences every level of the education system and is one of the most crucial catalysts for reform in science curriculum and instruction. Teachers, administrators, and others who choose, assemble, or develop assessments face the difficulty of judging whether tasks are truly aligned with national or state standards and whether they are effective in revealing what students actually know. Project 2061 of the American Association for the Advancement of Science has developed and field‐tested a procedure for analyzing curriculum materials, including their assessments, in terms of how well they are likely to contribute to the attainment of benchmarks and standards. With respect to assessment in curriculum materials, this procedure evaluates whether this assessment has the potential to reveal whether students have attained specific ideas in benchmarks and standards and whether information gained from students' responses can be used to inform subsequent instruction. Using this procedure, Project 2061 had produced a database of analytical reports on nine widely used science middle school curriculum materials. The analysis of assessments included in these materials shows that whereas currently available materials devote significant sections in their instruction to ideas included in national standards documents, students are typically not assessed on these ideas. The analysis results described in the report point to strengths and limitations of these widely used assessments and identify a range of good and poor assessment tasks that can shed light on important characteristics of good assessment. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 889–910, 2002
Simultaneous determination of potassium and rubidium content in yeast
Authors: Mulet Jose M. , Serrano Ramón 
Published: October 2002

AbstractRubidium is widely used as a potassium analogue in transport studies in yeast and other organisms. As rubidium (potassium) uptake is modulated by the internal potassium concentration, it is often necessary to determine both Rb+ and K+ concentrations in the same cell extract. Current methods based on atomic absorption/emission spectroscopy require separate analysis for each cation. Alternatively, unsafe radioactive isotopes can be used. Here we report a convenient, non‐radioactive, HPLC/conductivity‐based method that allows a complete analysis of both cations with a single injection from a cell extract. The increase in Rb+ uptake during K+ starvation in yeast is easily demonstrated with this method. Copyright © 2002 John Wiley & Sons, Ltd.
Proteins interacting with Lin1p, a putative link between chromosome segregation, mRNA splicing and DNA replication in Saccharomyces cerevisiae
Authors: Bialkowska Agnieszka , Kurlandzka Anna 
Published: October 2002

AbstractProteins involved in chromosome segregation during mitosis are likely to participate in other cell cycle‐coordinated processes. Using a two‐hybrid screen we identified a novel nuclear protein, Lin1, interacting with Irr1p/Scc3p, a component of the cohesin complex. The second round of two‐hybrid assay with Lin1p as the bait resulted in the identification of six proteins: Prp8, Slx5, Siz2, Wss1, Rfc1 and YIL149w. These proteins have previously been shown to participate in mRNA splicing, DNA replication, chromosome condensation, chromatid separation and alternative cohesion. We propose that Lin1p may constitute a link among these processes. Copyright © 2002 John Wiley & Sons, Ltd.
About town: The city and the female reader, 1860–1900
Authors: Caesar Ann Hallamore 
Published: October 2002

SummaryThe period after Italian Unification saw a marked increase in the volume of publications, magazines and books intended specifically for a female readership which was made up of girls and married women. It also saw the rise of the professional woman writer and journalist. Drawing on two of the most popular genres, the novel (in particular the domestic novel) and conduct literature, this article examines their representations of the city and urban life. It notes that while the physical transformation of major towns and cities was bringing in its wake far-reaching changes to the experience of urban life, the literature for women treats the city as an almost entirely abstract entity with few distinctive characteristics. Instead, the focus of these writings is on the drawing up of rulebooks designed to enable women to negotiate urban life without bringing opprobrium to bear on themselves or their families