bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultramicrotomy of semiconductors and related materials
Authors: Glanvill S. R. 
Published: February 2005

AbstractUltramicrotomy has found novel application in materials research using transmission electron microscopy, for both analytical and high resolution work. Specimens 20–50 nm in thickness with lateral dimensions of up to 100 microns may routinely be prepared, with the additional advantage of precise area location for cross‐sectional samples from real devices (e.g., VLSI structures). Much of this work is possible through the availability of diamond knives with various included angles and lengths at reasonable cost. This paper reports on various applications of ultramicrotomy, in particular, lattice imaging of surfaces and interface regions from epilayers of II–VI compound semiconductors and related materials. Ultramicrotomed cross‐sections have enabled modern electron beam imaging, diffraction and analytical techniques to be brought to bear near surfaces and across interfaces of multilayer structures, yielding high spatial resolution information on crystallography, defect structure and composition. © 1995 Wiley‐Liss, Inc.
Gap junctions in the vertebrate retina
Authors: Cook Jeremy E. , Becker David L. 
Published: February 2005

AbstractThe vertebrate retina is a highly laminated assemblage of specialized neuronal types, many of which are coupled by gap junctions. With one interesting exception, gap junctions are not directly responsible for the ‘vertical’ transmission of visual information from photoreceptors through bipolar and ganglion cells to the brain. Instead, they mediate ‘lateral’ connections, coupling neurons of a single type or subtype into an extended, regular array or mosaic in the plane of the retina. Such mosaics have been studied by several microscopic techniques, but new evidence for their coupled nature has recently been obtained by intracellular injection of biotinylated tracers, which can pass through gap junctional assemblies that do not pass Lucifer Yellow. This evidence adds momentum to an existing paradigm shift towards a population‐based view of the retina, which can now be envisaged both as an array of semi‐autonomous vertical processing modules, each extending right through the retina, and as a multi‐layered stack of interacting planar mosaics, bearing some resemblance to a set of interleaved neural networks. Junctional conductance across mosaics of horizontal cells is known to be controlled dynamically with a circadian rhythm, and other dynamically‐regulated conductance changes are also likely to make important contributions to signal processing. The retina is an excellent system in which to study such changes because many aspects of its structure and function are already well understood. In this review, we summarize the microscopic appearance, coupling properties and functions of gap junctions for each cell type of the neural retina, the regulatory properties that could be provided by selective expression of different connexin proteins, and the evidence for gap junctional coupling in retinal development. © 1995 Wiley‐Liss, Inc.
Spatial organization of cardiac gap junctions can affect access resistance
Authors: Hall James E. , Gourdie Robert G. 
Published: February 2005

AbstractIn the heart, gap junctions electrically couple myocytes together. Electron‐ and light‐microscope‐based analyses have revealed that cardiac gap junctions show a variety of organizational patterns. At the level of gap‐junctional channel aggregates, freeze fracture has demonstrated diverse channel packing arrangements in the membranes of different myocardial tissues. Ultrastructural and immunohistochemical studies have shown variation and specialization in the 3‐dimensional spatial distribution of gap junctional contacts between different types of myocardial cells. Here, we estimate the access resistance of various configurations of gap junctions using physical principles and explore how certain of these specializations in gap‐junctional organization may influence access resistance, a potentially important determinant of electrical conductance between coupled myocardial cells. © 1995 Wiley‐Liss, Inc.
Oviduct during early pregnancy: Hormonal regulation and interactions with the fertilized ovum
Authors: Murray Mary K. , Desouza Mary M. , Messinger Susan M. 
Published: February 2005

AbstractThe cyclic fluctuations in circulating levels of 17β‐estradiol and progesterone that occur during the menstrual or estrous cycle are responsible for dramatic, cyclic changes in the epithelial lining and secretory status of the mammalian oviduct. The timely transition in the synthesis and release of oviduct proteins, due to the ovarian steroids, and their interactions with oocytes, sperm, and the fertilized ovum underscore key biological events during gamete interactions and early embryonic cleavage. The regulation of these secretory alterations during the first few days of pregnancy is discussed with respect to the influence of the ovarian steroids, their interactions with the embryo microenvironment, and the possible ways in which they may mediate the critical reproductive events of fertilization and embryo development. © 1995 Wiley‐Liss, Inc.
Method for jet polishing two‐phase materials
Authors: Witcomb M. J. , Dahmen U. 
Published: February 2005

AbstractA two‐stage jet polishing technique is described which, utilising the effects of the characteristic current‐voltage behaviour of electropolishing solutions, can produce excellent TEM foils of relatively coarse two‐phase materials. © 1995 Wiley‐Liss, Inc.
Mammalian parathyroids: Morphological and functional implications
Authors: Wild Peter , Setoguti Takao 
Published: February 2005

AbstractFixation with aldehydes is achieved either by immersion or perfusion. The parenchyma of parathyroid glands fixed by immersion consists of dark cells containing a lot of membranes of those organelles which are concerned with hormone secretion, light cells which are poor in these organelles, intermediate forms between the two, and multinuclear syncytial cells. They have been attributed to represent different functional stages of secretory activity, the dark cell being in an active form, the light cell in a resting form. Studies of the parathyroids of mice, rats, rabbits, cats, dogs, pigs, cattle, sheep, goats, and horses employing various fixation protocols clearly demonstrate that light cell variants and multinuclear syncytial cells are formed during improper immersion fixation as a result of membrane disintegration. Parathyroids fixed by perfusion or by immersion in an appropriate fixation medium comprise only one cell type which correspond to the dark chief cell. Parathyroid cells are polar cells bearing some of the rough endoplasmic reticulum in the basal pole, the rest of it, the Golgi complex, and secretory granules in the apical pole. The secretory product is released by exocytosis at the apicolateral domain of the plasma membrane into the intercellular space. Secretory activity can be altered experimentally, leading to drastic changes in the amount of cell membrane related to hormone synthesis, intracellular transport, exocytic release, and secretion coupled membrane retrieval. The sensitive reaction of parathyroid cells to both the mode of fixation and to fixation media demands careful evaluation of the fixation protocol. This and the polarity of parathyroid ceils have to be borne in mind for estimating secretory activity on the basis of morphological criteria. © 1995 Wiley‐Liss, Inc.
Computer networked scanning electron microscope for teaching, research, and industry applications
Authors: Scott Chumbley L. , Meyer Mitch , Fredrickson Kjell , Laabs Fran 
Published: February 2005

AbstractA laboratory designed for teaching the operation of a scanning electron microscope (SEM) has been developed. The laboratory makes use of a computer network to allow remote operation of the SEM. Movable teaching stations, consisting of a computer, TV monitor, and joystick control, enable students to view the image on the SEM screen, move the sample, control the basic operating parameters of the microscope, and acquire X‐ray spectra. Images can also be stored on the computers for image analysis or incorporation into reports. The great advantage of the system is that it has been designed to be flexible enough to allow operation from any location that has access to the Internet. The system is relatively inexpensive and uses nonproprietary computer technology available at any computer store. While the laboratory has been designed for teaching, the concept of a multiuser SEM facility that is inexpensive and easy to install should have applications in both industrial and research settings. © 1995 Wiley‐Liss, Inc.
Arc reversal in nonhamiltonian circulant oriented graphs
Authors: Jirásek Jozef 
Published: February 2005

AbstractLocke and Witte described infinite families of nonhamiltonian circulant oriented graphs. We show that for infinitely many of them the reversal of any arc produces a hamiltonian cycle. This solves an open problem stated by Thomassen in 1987. We also use these graphs to construct counterexamples to Ádám's conjecture on arc reversal. One of them is a counterexample with the smallest known number of vertices. © 2005 Wiley Periodicals, Inc. J Graph Theory 49: 59–68, 2005
2‐factors with prescribed and proscribed edges
Authors: Aldred R. E. L. , Holton D. A. , Sheehan J. 
Published: February 2005

AbstractLet G be a finite k‐edge‐connected simple graph. We consider when a set of independent edges can be extended to a 2‐factor such that this 2‐factor avoids a fixed set of independent edges. A complete characterization is provided in those cases, where this is feasible. © 2005 Wiley Periodicals, Inc. J Graph Theory 49: 48–58, 2005
Biosynthesis of Polyhydroxyalkanoate (PHA) Copolymer from Fructose Using Wild‐Type and Laboratory‐Evolved PHA Synthases
Authors: Tsuge Takeharu , Yano Kotaro , Imazu Shin‐ichi , Numata Keiji , Kikkawa Yoshihiro , Abe Hideki , Taguchi Seiichi , Doi Yoshiharu 
Published: February 2005

AbstractSummary: Eleven laboratory‐evolved polyhydroxyalkanoate (PHA) synthases which originated from Pseudomonas sp. 61‐3 enzyme (PhaC1Ps), together with the wild‐type enzyme, were applied for PHA synthesis from fructose using Ralstonia eutropha PHB‐4 as a host strain. The evolved PhaC1Ps mutants had amino acid substitution(s) at position 325 and/or position 481. In these mutants, serine‐325 (S325) was replaced by cysteine (C) or threonine (T), while glutamine‐481 (Q481) was replaced by lysine (K), methionine (M) or arginine (R). All recombinant strains harboring the genes of the evolved PhaC1Ps mutants produced a significantly increased amount of PHA (55–68 wt.‐%) compared with the one harboring the wild‐type gene (49 wt.‐%). Particularly, those evolved PhaC1Ps mutants having multiple amino acid substitutions showed higher activities for PHA synthesis. Characterization of the PHA by NMR spectroscopy revealed that they were copolymers consisting of (R)‐3‐hydroxybutyrate (98–99 mol‐%) and medium‐chain‐length comonomers (1–2 mol‐%). This study also confirmed that amino acid substitution at position 481 in PhaC1Ps led to an increasing molecular weight of PHA. The number‐average molecular weight ($\overline M _{\rm n}$) of PHA ($\overline M _{\rm n}$ = 240 000) synthesized by the evolved PhaC1Ps (Q481K) mutant was 4.6‐fold greater than that ($\overline M _{\rm n}$ = 52 000) synthesized by the wild‐type enzyme.PHA content in recombinant R. eutropha PHB‐4 expressing the wild‐type or the laboratory‐evolved PHA synthase.magnified imagePHA content in recombinant R. eutropha PHB‐4 expressing the wild‐type or the laboratory‐evolved PHA synthase.
Cover: Macromol. Mater. Eng. 2/2005
Authors: Pfister Andreas , Walz Uwe , Laib Andres , Mülhaupt Rolf 
Published: February 2005

Cover: For the first time zinc polycarboxylate ionomers have been used successfully as a powder material for the rapid prototyping technology 3D Printing™. The resulting 3D models show water resistance, which is rather unique with respect to the conventional materials which are processed using the ZCorporation 3D printers or the Deskmodeler™. Advantageous are also the increased mechanical and dimensional stability of the 3D models printed by means of these new materials.Further details can be found in the Full Paper by A. Pfister, U. Walz, A. Laib, and R. Mülhaupt* on page 99.
Synthesis of a Novel ABC Triblock Copolymer with a Rigid‐Rod Block via Atom Transfer Radical Polymerization
Authors: Zhang Hailiang , Sun Xiaoyi , Wang Xiayu , Zhou Qi‐Feng 
Published: February 2005

AbstractSummary: A novel ABC triblock copolymer with a rigid‐rod block was synthesized by atom transfer radical polymerization (ATRP). First, a poly(ethylene oxide) (PEO)‐Br macroinitiator was synthesized by esterification of PEO with 2‐bromoisobutyryl bromide, which was subsequently used in the preparation of a poly(ethylene oxide)‐block‐poly(methyl methacrylate) (PEO‐b‐PMMA) diblock copolymer by ATRP. A poly(ethylene oxide)‐block‐poly(methyl methacrylate)‐block‐poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene} (PEO‐b‐PMMA‐b‐PMPCS) triblock copolymer was then synthesized by ATRP using PEO‐b‐PMMA as a macroinitiator.ABC triblock copolymer with a rigid‐rod block.magnified imageABC triblock copolymer with a rigid‐rod block.
Glass Transition Temperature Depression at the Percolation Threshold in Carbon Nanotube–Epoxy Resin and Polypyrrole–Epoxy Resin Composites
Authors: Barrau Sophie , Demont Philippe , Maraval Céline , Bernes Alain , Lacabanne Colette 
Published: February 2005

AbstractSummary: The glass transition temperatures of conducting composites, obtained by blending carbon nanotubes (CNTs) or polypyrrole (PPy) particles with epoxy resin, were investigated by using both differential scanning calorimetry (DSC) and dynamical mechanical thermal analysis (DMTA). For both composites, dc and ac conductivity measurements revealed an electrical percolation threshold at which the glass transition temperature and mechanical modulus of the composites pass through a minimum.DC conductivity, σdc, as a function of the conducting filler concentration of the CNT– (▪) and PPy– (○) epoxy resin composites.magnified imageDC conductivity, σdc, as a function of the conducting filler concentration of the CNT– (▪) and PPy– (○) epoxy resin composites.
Diffusion Interface Technique for Determination of Initial Polymerization Kinetics
Authors: Skoumal Miroslav , Cejpek Igor , Cheng Chung Ping 
Published: February 2005

AbstractSummary: A new procedure for the investigation of initial kinetics in a slurry olefin polymerization with a Ziegler‐Natta catalyst has been developed. It is based on the accurate timing of short polymerizations that result from the immediate start of a reaction between a catalyst separated in an oil phase and the remaining components of the system upon their being mixed together. The polymer samples are suitable for 13C NMR analysis and the number of active sites could be calculated.Schematic illustration of the oil (catalyst)/heptane (monomer‐cocatalyst) diffusion interface.magnified imageSchematic illustration of the oil (catalyst)/heptane (monomer‐cocatalyst) diffusion interface.
Corticobasal syndrome with novel argyrophilic glial inclusions
Authors: Rippon Gregory A. , Staugaitis S.M. , Chin Steven S.M. , Goldman James E. , Marder K. 
Published: February 2005

AbstractA 42‐year‐old, left‐handed woman first noted impaired dexterity of the dominant hand, soon followed by dysarthria and cognitive decline. Over a 4‐year period, she developed severe left‐sided apraxia with eventual neglect of the left arm and progressive extrapyramidal signs. Cognitive testing showed progressive executive, visuospatial, fluency, and naming impairment with relative preservation of memory. Single‐photon emission computed tomography demonstrated asymmetric right posterior frontal and superior parietal hypoperfusion. The clinical impression was corticobasal degeneration. At autopsy, severe atrophy was seen in the perirolandic and frontal regions. There was marked neuronal loss and gliosis in the posterior frontal and precentral regions and less severe pathology in prefrontal, temporal, and parietal areas. Mild to moderate gliosis and neuronal loss were also seen in the putamen, globus pallidus, subthalamic, and dentate nuclei. Gallyas silver stain revealed numerous inclusions adjacent to oligodendrocyte nuclei in white and gray matter of affected cortical and subcortical regions. The gracile inclusions were wavy, slender, and stained positively with antibodies to ubiquitin and αB‐crystallin but not to microtubule‐associated proteins (tau, MAP1B, MAP2), tubulin, neurofilaments, glial fibrillary acidic protein, or α‐synuclein. The argyrophilic inclusions identified in this case are distinct from those previously described in neurodegenerative diseases. © 2005 Movement Disorder Society
End‐of‐dose akinesia after a single intravenous infusion of the dopaminergic agonist piribedil in Parkinson's disease patients: A pharmacokinetic/pharmacodynamic, randomized, double‐blind study
Authors: Simon Nicolas , Micallef Joëlle , Reynier Jean‐Charles , Lesourd Monique , Witjas Tatiana , Alicherif André , Azulay Jean‐Philippe , Blin Olivier 
Published: February 2005

AbstractThis randomized, double‐blind trial was designed to define the possible relationship between piribedil plasma concentrations and the decrease of the Unified Parkinson's Disease Rating Scale (UPDRS) motor score or the switch from off to on state after single intravenous infusion. Ten fluctuating patients with idiopathic Parkinson's disease (PD) received escalating doses of piribedil (2–16 mg) and placebo. Starting from 2 mg, piribedil was effective in reducing the motor deficit (UPDRS, motor score) including akinesia at the first evaluation time point of 15 minutes, and in reversing off state of 7 of 10 patients. The doses were equally effective, although the effect was more sustained with the highest dose of 16 mg. Piribedil was well tolerated up to a 16‐mg dose and pharmacokinetics were linear up to the 16‐mg dose. Plasma levels of piribedil were not correlated to the motor score improvement or switch from off→on. In conclusion, a short single infusion of piribedil at 2 to 16 mg was safe and effective in improving motor symptoms, including akinesia, of fluctuating PD patients. © 2005 Movement Disorder Society
Adult‐onset neuronal ceroid lipofuscinosis type B in an African‐American
Authors: Ivan Cristina S. , Saint‐Hilaire Marie H. , Christensen Thomas G. , Milunsky Jeff M. 
Published: February 2005

AbstractWe describe a rare case of adult‐onset neuronal ceroid lipofuscinosis (NCL) type B with probable autosomal dominant inheritance, exhibiting behavioral and cognitive abnormalities and extrapyramidal findings. Ultrastructural examination revealed abundant fingerprint profiles in several cell types. To our knowledge, this is the first reported case of an African‐American with adult‐onset NCL. © 2005 Movement Disorder Society
Endometrial expression of progesterone receptor and uteroglobin genes during early pregnancy in the rabbit
Authors: Gutierrez‐Sagal Ruben , Perez‐Palacios Gregorio , Langley Elizabeth , Pasapera Ana Maria , Castro Ivone , Cerbón Marco Antonio 
Published: February 2005

AbstractThe progesterone receptor (PR) plays a pivotal role in the maturation process of the secretory endometrium, implantation and maintenance of pregnancy in rabbits. To determine the dynamics of PR gene expression and its physiological significance, the endometrial expression of PR and PR mRNA were evaluated and compared with the expression of the progesterone‐regulated uteroglobin (UG) gene during 0–5 days post‐coitus in rabbits. The results of immunoblot experiments indicated the presence of PR in endometrial cell extracts from days 1–4 of pregnancy with maximum PR immunostaining on day 2, followed by a marked diminution until its complete disappearance on day 5. When endometrial PR mRNA content was assessed by Northern blots, the results were similar to those of PR immunostaining, with maximal concentrations on the second day after mating. However, PR mRNA levels were still high on day 3, despite the concomitant decrease in immunostainable PR. Endometrial UG gene expression, on the other hand, exhibited a different time sequence. Thus, the UG content in uterine flushings progressively increased from day 3 after mating, reaching maximal levels on the fifth day. The endometrial UG mRNA content presented a similar profile, as its maximum concentration occurred on days 4–5. The overall results indicate that endometrial PR is down‐regulated at both the mRNA and protein levels, possibly by endogenous progesterone during early pregnancy. The striking observation that maximal expression of endometrial UG gene products occurred when PR and its mRNA are no longer detectable suggests an important role for this progesterone‐binding uterine protein during the preimplantation period. © 1993 Wiley‐Liss, Inc.
Successful vitrification of bovine blastocysts, derived by in vitro maturation and fertilization
Authors: Tachikawa S. , Otoi T. , Kondo S. , Machida T. , Kasai M. 
Published: February 2005

AbstractBovine blastocysts were produced through maturation, fertilization, and development in vitro. For vitrification, solutions designated EFS, GFS, and PFS were prepared; these were 40% ethylene glycol, 40% glycerol, and 40% propylene glycol, respectively, diluted in modified phosphate‐buffered saline (PBS) containing 30% Ficoll + 0.5 M sucrose. The embryos were exposed to the solutions in one step at room temperature, kept in the solutions for various times, vitrified in liquid nitrogen, and warmed rapidly. When the embryos were vitrified in EFS solution after 1 or 2 min exposure, the postwarming survival rate, assessed by the reexpansion of the blastocoel, was 74–77%. However, when the exposure time was extended to 3 min or longer, this rate dropped to 7–0%. This reduction was attributed to the toxicity of ethylene glycol. Of the embryos vitrified in GFS solution, 53% survived when they were cooled after 1 min exposure; as the duration of the exposure increased, the survival rate increased, reaching a peak (72%) at 4 min. The rate then decreased gradually with exposure time. In PFS solution, embryos surviving after vitrification were recovered only with 1 min exposure (33%), reflecting the high toxicity of propylene glycol. After vitrification in EFS or GFS solution, two embryos were nonsurgically transferred into each of 14 recipient animals. Of the 14 recipients, ten (71%) became pregnant; two resulted in early stillbirths, four recipients delivered twins (four alive and four stillborn), and two delivered single live calves, demonstrating the effectiveness of this simple vitrification method for the cryopreservation of in‐vitro‐produced bovine blastocysts. © 1993 Wiley‐Liss, Inc.