showing 36 of ~574560 from 574555 documents
Electron transport chain in aerobically cultivated Zymomonas mobilis
1996
Respiratory chain composition and energy coupling in cytoplasmic membrane of Zymomonas mobilis was shown to depend on culture aeration. Aerobically grown cells contained mainly the non-energy-generating NADH dehydrogenase with kM for NADH 58 mM. In anaerobically cultivated bacteria, the energy-coupling NADH dehydrogenase complex with km for NADH 7 mM predominated. In aerobically cultivated Z. mobilis, CoQ content and absorption peaks of cytochromes at 554–556 nm and 525–528 nm were significantly increased. Energy-coupling site I, linked to the NADH:CoQ oxidoreductase complex, could be eliminated under sulfate-deficient cultivation conditions. For anaerobically grown cells this resulted in l…
Genetic variation in natural populations of the aphid Rhopalosiphum padi as revealed by maternally inherited markers
1996
A survey on 148 clones of the aphid Rhopalosiphum padi from 11 widespread localities has been carried out to study the genetic structure of populations of this species as revealed by mitochondrial DNA restriction site and length polymorphisms as well as by restriction site analysis of a maternally inherited plasmid carried by the aphid eubacterial endosymbiont Buchnera aphidicola. Our results support the existence in the area under study of two main aphid maternal lineages strikingly coincidental with the two main reproductive categories displayed by this species. Those aphid clones possessing an incomplete life cycle that lacks the sexual phase (anholocyclic or androcyclic clones) show mit…
Anisotropic Stick-slip friction of highly oriented thin films of poly(tetrafluoroethylene) at the molecular level
1996
Lateral force microscopy (LFM) studies of poly(tetrafluoroethylene) (PTFE) films with molecular resolution are reported. Thin PTFE layers with a high degree of orientation were obtained by pressing and sliding a block of polymer on a clean, heated muscovite mica substrate. LFM nanographs obtained on these films by scanning at directions between ca. 40 and 90° with respect to the film orientation direction, i.e. with respect to the direction of the polymer chains, showed a “stick-slip” type frictional motion of the LFM probe tip at the molecular level. The friction force observed at constant load decreased with decreasing scan angles. Chain-chain packing distances obtained by LFM and contact…
Membrane-penetrating Domain of Streptolysin O Identified by Cysteine Scanning Mutagenesis
1996
Streptolysin O (SLO), a polypeptide of 571 amino acids, belongs to a family of highly homologous toxins that bind to cell membranes containing cholesterol and then polymerize to form large transmembrane pores. A conserved region close to the C terminus contains the single cysteine residue of SLO and has been implicated in membrane binding, which has been the only clear assignment of function to a part of the sequence. We have used a cysteine-less active mutant of SLO to introduce single cysteine residues at 19 positions distributed throughout the sequence. The cysteines were derivatized with the polarity-sensitive fluorophore acrylodan, and the fluorescence emission of the label was examine…
Thermal behavior and spherulitic superstructures of SBC triblock copolymers based on polystyrene (S), polybutadiene (B) and a crystallizable poly(ɛ-c…
1996
The dynamic crystallization and the melting behavior of polystyrene-block-poly(e-caprolactone) (PS-b-PCL, short notation SC), polybutadiene-block-poly(e-caprolactone) (PB-b-PCL, BC) and polystyrene-block-polybutadiene-block-poly(e-caprolactone) (PS-b-PB-b-PCL, SBC) have been studied using differential scanning calorimetry. The copolymers with high molecular weight exhibit microphase separation into microphases consisting of polystyrene, polybutadiene and poly(e-caprolactone) and partial crystallization of the corresponding PCL block. The crystallization occurs at temperatures below the PS glass transition. Depending on the block copolymer composition, crystallization takes place through a c…
6th International Congress on Neuronal-Ceroid-Lipofuscinosis (NCL-96), June 8–11, 1996, Gustavelund, Finland
1996
Strange vesicles with a homogeneous content in spermatocytes and spermatids of a click beetle, Adelocera murina (Elateridae). A fine structure study
1996
Abstract The restructuring of primary spermatocytes of Adelocera murina, a click beetle, is described using electron microscopy of ultrathin sections. Emphasis is on spherical or rod-shaped cytoplasmic inclusions, invested by a unit membrane. The content of the inclusions is slightly more electron-dense than that of the surrounding cytoplasm and homogeneously textured in most cases. The inclusions are missing in spermatogonia but are abundant in prophase I through anaphase I spermatocytes. Their number declines in telophase I. Very similar elements are associated with the distal ends of the outgrowing flagella in metaphase I through telophase I spermatocytes and form the so-called flagellar…
The mean square nuclear charge radius of
1996
We report on a collinear laser spectroscopy measurement of the nuclear charge radius of (I = 3/2), yielding . Within the experimental accuracy, the N = 20 neutron shell closure has no influence on the charge radii of the calcium isotopes.
Mandibular incisor extraction: indications and long-term evaluation
1996
The extraction of a lower incisor constitutes a therapeutic alternative limited to certain occlusal situations, i.e. supernumerary incisors, tooth size anomalies (peg-shaped upper laterals), ectopic eruption and anterior crossbites. The effect of the extraction of a single incisor on the out of retention alignment of lower anterior teeth was studied in 26 treated cases. Initial (T1), final (T2) and 5-8 years out of retention (T3) dental casts were measured. Mean crowding at the start of treatment (T1 = 3.86 mm) relapsed out of retention (T3 = 1.49 mm), with a net mean improvement of 2.37 mm. Little's irregularity index at the start of treatment (T1 = 6.44) relapsed out of retention (T3 = 2.…
Treatment with the anti-tumor drugs, cis-platin and mafosfamide, does not affect the structure of prekinetochores in a human breast cancer cell line.…
1996
Abstract The goal of the present article was to determine whether a nuclear parameter, centromere structure of interphase cells, could serve as an indicator to assess cellular damage caused by anti-tumor drugs. These were cis-platin and mafosfamide, which are widely used for the management of solid tumors. To visualize the centromeres, we probed treated and untreated cells of a human breast cancer cell line, MX-1, with a human anti-centromere serum. The serum was obtained from a scleroderma patient and detects antigens associated with prekinetochores of the decondensed chromosomes. The DNA was simultaneously displayed by a specific fluorescent dye. The cells were grown on coverslips, incuba…
Modulational instability and critical regime in a highly birefringent fiber
1996
We report experimental observations of modulational instability of copropagating waves in a highly birefringent fiber for the normal dispersion regime. We first investigate carefully the system behavior by means of nonlinear Schr\"odinger equations and phase-matching conditions, and then, experimentally, we use two distinct techniques for observing MI (modulational instability) in the fiber; namely, the single-frequency copropagation, where two pump waves of identical frequency copropagate with orthogonal polarizations parallel to the two birefringence axes of the fiber, and the two-frequency copropagation, where the two polarized waves copropagate with different frequencies. In both cases …
Mean field behaviour of Sr1−xCaxTiO3
1996
A systematic analysis of the dielectric constant as a function of temperature in SrTiO 3 : Ca crystals with Ca content of 0.0020, 0.0032, 0.0055. 0.0058, and 0.0110 shows that the Barrett parameters are clearly modified by the Ca content. We have found for each Ca concentration the temperature below which the contribution of the Ca induced clusters becomes sizeable. The values obtained for the fitted parameters in the Barrett formula allow us to trace a boundary between the low-temperature quantum paraelectric and ferroelectric regimes.
Phylogeny and species limits in the Palaearctic chiffchaffPhylloscopus collybitacomplex: mitochondrial genetic differentiation and bioacoustic eviden…
1996
Nucleotide sequences of the mitochondrial cytochrome b gene (1041 bp), analysis of vocalizations and behavioural evidence from zones of contact were used to reassess the species limits and phylogenetic relationships at the species and subspecies levels in the Phylloscopus collybita complex. A new classification is proposed which recognizes four biological species. Phylloscopus brehmii (Iberia) and P. canariensis (Canary Islands) are genetically and bioacoustically highly distinct. There is no mitochondrial gene flow between them or with P. collybita. The Mountain Chiffchaff P. sindianus (with subspecies sindianus and Iorenzii) is equally distinct genetically from southwest Asian subspecies …
Molecular evolution of the metazoan protein kinase C multigene family
1996
Protein kinases C (PKCs) comprise closely related Ser/Thr kinases, ubiquitously present in animal tissues ; they respond to second messengers, e.g., Ca2+ and/or diacylglycerol, to express their activities. Two PKCs have been sequenced from Geodia cydonium, a member of the lowest multicellular animals, the sponges (Porifera). One sponge G. cydonium PKC, GCPKC1, belongs to the ''novel'' (Ca2+-independent) PKC (nPKC) subfamily while the second one, GCPKC2, has the hall-marks of the ''conventional'' (Ca2+-dependent) PKC (cPKC) subfamily. The alignment of the Ser/Thr catalytic kinase domains, of the predicted aa sequences for these cDNAs with respective segments from previously reported sequence…
Polymer microscopy, 2nd edition. by L. C. Sawyer, D. T. Grubb, Chapman & Hall, London 1996, xii, 397 pp., hardcover, £85.00, ISBN 0-412-60490-6
1996
Physiological activation of the IgH 3' enhancer in B lineage cells is not blocked by Pax-5.
1996
The mouse 3' enhancer contains a high-affinity binding site for the paired box protein Pax-5. Here, we demonstrate by genomic footprinting that the rat 3' enhancer contains a low-affinity binding site for Pax-5, which is occupied in activated splenic B cells. Thus, binding of Pax-5 to the IgH 3' enhancer appears to be evolutionarily conserved in rodents. Analysis of Pax-5 expression in primary B cells demonstrates that Pax-5 remains expressed after 4 days of lipopolysaccharide (LPS) induction, but is down-regulated in 5-day stimulated cells. Similarly, the expression of Pax-5 is down-regulated in vivo in activated large splenocytes, in contrast to small resting cells. Multimerization of the…
Effect of Soluble Interleukin-6 Receptor on Interleukin-6 Synthesis in Human Skin Fibroblasts
1996
Abstract In this study the ability of soluble interleukin-6 receptor (sIL-6R) to stimulate interleukin-6 (IL-6) synthesis in human fibroblasts is described. It was found that sIL-6R, in combination with endogenous or exogenous IL-6, markedly upregulated IL-6 synthesis. These data suggest that increased IL-6 production after stimulation by either interleukin-1 or tumor necrosis factor-α would result in complex formation with sIL-6R, rapid uptake, and further synthesis of this cytokine. Furthermore, it would explain the decrease in sIL-6R plasma levels observed in patients suffering from sepsis.
Selective approach to the treatment of oesophageal cancer
1996
Abstract Between September 1985 and December 1994, 322 patients with oesophageal cancer were treated. Of the 190 patients who underwent operation, 173 had an oesophageal resection; in 124 this was performed as an abdominothoracic resection and in 49 by the transhiatal approach. The assessment of radicality after histological examination revealed a curative (R0) resection in 121 patients (70 per cent) and a palliative (R1-R2) resection in 52 (30 per cent). Prognosis was correlated with the extent of mediastinal lymph node dissection. In 77 patients with stage pT1–3 pN0–1 pM0 the 5-year survival rate was 40 per cent after abdominothoracic resection with two-field lymph node dissection and zer…
Two fungal lanostane derivatives as phospholipase A2 inhibitors.
1996
The hydroalcoholic extract of Poria cocos and two lanostane derivatives isolated from it, pachymic acid (1) and dehydrotumulosic acid (2), were active as inhibitors of phospholipase A2 from snake venom when a polarographic method was used. Dehydrotumulosic acid exhibited an IC50 of 0.845 mM. These two compounds are structurally related to certain triterpenoids from Ganoderma and Schinus that have previously been described as competitive inhibitors of phospholipase A2. These comprise a new group of natural potential antiinflammatory agents due to their interaction with that enzyme.
Tolerancia y Derecho. ¿Tiene sentido hablar de tolerancia como principio jurídico?
1996
Micropropagation of globe artichoke (Cynara scolymus L.) from underground dormant buds (“ovoli”)
1996
Side shoots excised from underground dormant buds ofCynara scolymus L. were used as primary explants to establishin vitro cultures. A 3×3 factorial experiment with all possible combinations of three concentrations (0.5, 1.0, 2.0 mg/liter or 2.22, 4.44, 8.88 μM) ofN 6-benzyladenine (BA) and three concentrations (0, 0.1, 0.2 mg/liter or 0, 0.54, 1.07 μM) of 1-naphthaleneacetic acid (NAA) was used to determine the optimum growth regulator combination for shoot multiplication. The highest rate of axillary shoots was induced on Murashige and Skoog agar medium supplemented with 0 mg NAA/liter and 1.0 mg BA/liter (4.44 μM). Other cytokinins tested (kinetin, zeatin, and 2-isopentenyl-adenine were l…
Childhood Family Problems and Current Psychiatric Problems among Young Violent and Property Offenders
1996
The main objective was to examine whether young property and violent offenders would differ from each other in the prevalence of childhood abuse and neglect experiences, prevalence of various early family problems, and prevalence of disruptive behavior disorders, depression, and substance use.Childhood abuse and neglect assessments and family problems were based on interview, questionnaire, and file data. Psychiatric diagnoses were made on the basis of a structured clinical interview.There were no statistically significant differences in the prevalence of childhood physical or psychological abuse, or neglect between the groups. According to the files, physical abuse was experienced by 57.5%…
Polyalthidin: New Prenylated Benzopyran Inhibitor of the Mammalian Mitochondrial Respiratory Chain
1996
Polyalthidin (3), a new benzopyran derivative, was isolated from the stem bark of Polyalthia cerasoides. Its structure was established on the basis of chemical and spectral evidence. Polyalthidin has showed potent biological activity as an inhibitor of the mammalian mitochondrial respiratory chain.
Torsional effects on the molecular polarizabilities of the benzothiazole (A)-benzobisthiazole (B) oligomer A-B13-A
1996
Abstract We outline a method for the calculation of multipole moments and molecular dipole-dipole ( ), dipole-quadrupole ( ), and quadrupole-quadrupole ( ) polarizabilities, which we have successfully applied to benzothiazole (A)-benzobisthiazole (B) oligomer A-B13-A. Three model rotational isomers have been characterized: (1) the fully planar (000) rotational isomer; (2) a conformation with each unit rotated 10° in the alternate direction (+−+), and (3) a rotational isomer with each unit rotated 10° in the same direction (+++). The dipole moment, μ , is smaller for isomers 000 and +−+ than for isomer +++. The calculation of , , and has been performed by use of the interacting induced dipol…
Adaptive Lung Ventilation (ALV) Evaluierung eines neuen closed loop-gesteuerten Beatmungsalgorithmus bei Eingriffen in �berstreckter Seitenlage
1996
The lateral decubitus position is the standard position for nephrectomies. There is a lack of data about the effects of this extreme position upon respiratory mechanics and gas exchange. In 20 patients undergoing surgery in the nephrectomy position, we compared a new closed-loop-controlled ventilation algorithm, adaptive lung ventilation (ALV), which adapts the breathing pattern automatically, to the respiratory mechanics with conventionally controlled mandatory ventilation (CMV). The aims of our study were (1) to describe positioning effects on respiratory mechanics and gas exchange, (2) to compare ventilatory parameters selected by the ALV controller with traditional settings of CMV, and …
Dynamic heterogeneity in supercooled ortho-terphenyl studied by multidimensional deuteron NMR
1996
Using deuteron NMR, we have studied molecular reorientation rates and rate exchange processes in supercooled ortho-terphenyl. We monitor the re-equilibration of differently selected subensembles through four-time stimulated echo experiments. A comparison of the two-time with the four-time echoes suggests that the characteristic time scales for reorientation and dynamical exchange are relatively similar. The four-time correlation functions were described using various multi-state rate exchange models.
Un analisis de los gasto privados de educacion en Espana en 1991
1996
Référence interne : 96098
Lumbar Disc Degeneration and Sagittal Flexibility
1996
It is uncertain whether intervertebral disc degeneration is associated with reduced or increased flexibility, although lumbar flexibility is known to reduce with advancing age. This cross-sectional study of 214 middle-aged men attempted to determine the influence on lumbar sagittal flexibility from intervertebral disc degeneration parameters measured from magnetic resonance images (disc height, signal intensity, bulging, osteophytes). Multivariate analyses showed that a reduced extent of lumbar flexibility could be accounted for by the combined effect of decreasing disc height together with increasing age, weight, and back pain frequency. Although it remains possible that single degenerate …
Bewegungen der Kiefergelenke w�hrend der endotrachealen Intubation
1996
Zwischen der Funktion der Kiefergelenke und der Intubation besteht eine wechselseitige Beziehung: Dysfunktionen konnen ein Intubationshindernis darstellen. Die Intubation kann umgekehrt auch zu Funktionsstorungen im orofazialen System fuhren oder Ausloser akuter Kiefergelenkbeschwerden sein. Eine Aussage zu der nach Aufhebung der physiologischen Schutzmechanismen moglicherweise veranderten Motilitat war bislang nicht moglich. Die Arbeit beschreibt die Anwendung einer Methode zur Erfassung der Kiefergelenkbewegungen sowie typische Befunde wahrend der Intubation. Das Prinzip der elektronischen Achsiographie wurde dahingehend modifiziert, das der Vergleich einer aktiven Mundoffnungsbewegung mi…
Role of sinusoidal endothelial cells of the liver in concanavalin A-induced hepatic injury in mice
1996
CD4+ T lymphocytes have been identified as being responsible for organ damage in the murine model of experimental liver injury induced by intravenous injection of concanavalin A (Con A). Liver sinusoidal endothelial cells (SEC) and Kupffer's cells (KC) are among the first cells that come into contact with lymphocytes in the liver sinusoid. We aimed to investigate the respective role of these cell populations in the initial steps of T-cell-mediated liver injury in Con A-induced hepatitis. By electron microscopy, we could show that intravenously applied Con A bound predominantly to SEC but not to KC. KC depletion by gadolinium chloride treatment of mice did not result in protection from liver…
Quantum extensions of semigroups generated by Bessel processes
1996
We construct a quantum extension of the Markov semigroup of the classical Bessel process of orderv≥1 to the noncommutative von Neumann algebra s(L2(0, +∞)) of bounded operators onL2(0, +∞).
First observation of nonyrast levels inZr103and level systematics ofN= 63 Sr, Zr, and Mo isotones
1996
The {beta} decay of the very-neutron-rich nucleus {sup 103}Y has been studied at the isotope separator IGISOL, allowing for the first time the observation of nonyrast levels in its daughter {sub 40}{sup 103}Zr{sub 63}. The level structure is similar to that of its isotones {sup 101}Sr and {sup 105}Mo, suggesting a large ground-state deformation of {beta}{approx_equal} 0.4. Level systematics allows for new level assignments in both {sup 103}Zr and {sup 105}Mo. {copyright} {ital 1996 The American Physical Society.}
Heat and mass flows coupled with stress in a continuous medium
1996
Abstract The present paper is concerned with the formulation of the generalization of theories describing heat and mass flows in a continuous medium. The considerations are based on the non-equilibrium thermodynamics. As a result the fundamental equations for the mass and heat fluxes and for the thermodynamic and mechanical fields, are obtained and the corresponding set of differential equations is formulated. Certain differences are pointed out between the general theories presented here and the thermodiffusion theory and the theory of mixtures. A thermodynamic variational principle is constructed. All the investigations concern only flows with a single temperature field. Copyright © 1996 …
Effect of landscape structure on common vole (Microtus arvalis) distribution and abundance at several space scales
1996
This paper aims to answer the following question: are the fluctuations of abundance of Common Vole (Microtus arvalis) specific to different types of landscapes? The research was carried out in landscapes where grassland was dominant. The sampling method was based upon a partition in both landscape types and landscape units. Tracking of vole indices was used to evaluate their relative abundance. Six landscape transects were sampled during two successive years. Results show that population variation and diffusion of demographic states are closely related to landscape types. The possible causes of this are discussed. The landscape units can be used as global variables to assess outbreak risk a…
Distribution of soil animals in patchily contaminated soil
1996
Abstract Distribution of soil animals with respect to patchy chemical contamination was studied in microcosms containing reconstituted coniferous forest floor. Soil materials were defaunated and soil organisms were reinoculated into a mesh basket in the centre of each microcosm. Part of the humus layer was contaminated with three concentrations of sodiumpentachlorophenate (0, 50 or 500 mg PCP kg −1 of dry humus) and put into mesh baskets (two per concentration) around the central patch. No differences in dispersion ability from the reinoculated patch were found between microarthropod species. PCP decreased microbial biomass in the humus. Numbers of collembolans were significantly lower in t…