Structural dynamics in F1ATPase during the first reaction cycle of ATP hydrolysis

1991

Abstract The velocity of ATP hydrolysis, catalyzed by purified F 1 ATPase from Micrococcus luteus , was decelerated on decreasing the temperature. At 13′C one reaction cycle is completed after 20 s. Hydrolysis was triggered upon rapid mixing of the enzyme with ATP. During the first reaction cycle, succeeding structural alterations of the F 1 ATPase were traced by time resolved X-ray scattering. The scattering spectra obtained from consecutive intervals of 1 s, revealed the F 1 ATPase to pass a conformational state exhibiting an expanded (6%) molecular shape. The expanded state was observed between 45% and 65% of the time required to complete the reaction cycle. This pointx out a conformatio…

Association de Penicillium camemberti Geotrichum candidum. effets sur la qualité sensorielle de camemberts

1991

National audience

Afferent and efferent connections of the olfactory bulbs in the lizard Podarcis hispanica.

1991

The connections of the olfactory bulbs of Podarcis hispanica were studied by tract-tracing of injected horseradish peroxidase. Restricted injections into the main olfactory bulb (MOB) resulted in bilateral terminallike labeling in the medial part of the anterior olfactory nucleus (AON) and in the rostral septum, lateral cortex, nucleus of the lateral olfactory tract, and ventrolateral amygdaloid nucleus. Bilateral retrograde labeling was found in the rostral lateral cortex and in the medial and dorsolateral AON. Ipsilaterally the dorsal cortex, nucleus of the diagonal band, lateral preoptic area, and dorsolateral amygdala showed labeled cell bodies. Retrogradely labeled cells were also foun…

The neuro-B cell link of peptidergic innervation in the Bursa Fabricii

1991

The Bursa Fabricii, restricted to birds, specifically provides the microenvironment for B-cell maturation. The presence of nerve fibers containing immunopotent neuropeptides in immune organs opens interesting perspectives on the understanding of neuroimmune communication. As an organ for the development of only B-lymphocytes is not known in mammals, the contribution of a peptidergic innervation to the microenvironment of B-cells is not known. Therefore, we studied the peptidergic innervation of the Bursa Fabricii as an organ of B-cell maturation. Four different neuropeptides were found in nerve fibers of the Bursa Fabricii: tachykinins (TK), vasoactive intestinal peptide (VIP), galanin (GAL…

An Intercalibration Study of the Use of 4-Methylumbelliferyl-β-D-Glucuronide for the Specific Enumeration of Escherichia coli in Seawater and Marine …

1991

Summary A fluorogenic assay for the specific detection of Escherichia coli on the basis of its β-glucuronidase activity (MUG method) was applied to seawater and marine sediments with different contamination levels. The study was carried out in three Mediterranean areas (Malaga-Spain, Nice-France and Palermo-Sicily), using strictly standardized methods (membrane filtration), media (mFC and Chapman-TTC agars) and reagents, to evaluate statistically its sensitivity and specificity according to the origin and contamination of samples, the workers performing the tests and the selected culture media. The results obtained indicate that the MUG method is highly specific (94.5%) and sensitive (90.8%…

Collective excitations of 3He clusters

1991

Collective excitations of3He clusters are studied by treating the cluster as a quantum liquid drop. We have used the Random-Phase Approximation sum rules technique within a Density Functional Formalism. Results forL=2 to 10 surface modes and theL=0 volume mode are presented.

Well-posed nonlinear problems in integrated circuits modeling

1991

In this paper we study the problem (E) + (BC) + (IC) (see below) which represents a model for integrated circuits. We assume that the distributed parametersr(x) andc(x) are nonconstant, dielectric leakages depend on thex-coordinate as well as the voltage level, while the interconnecting multiport is nonlinear and possibly multivalued.

The response of metal clusters toq- andL-dependent external fields

1991

We have calculated the static polarizability and mean excitation energy of metal clusters submitted toq-andL-dependent external fields ofjL(qr)YL0(Ω) type. Use has been made of an Extended Random-Phase Approximation which includes exchange and correlation effects within a local model, and of the spherical jellium model to describe the neutralizing positive background.

Uniform properties of collections of convex bodies

1991

On Banaschewski functions in lattices

1991

hold for all x, y ~ X. We call such a function z a Banaschewski function or a B-function on X. A lattice L is a B-lattice or antitonely complemented, if there is a B-function defined on the whole lattice L. For instance, Boolean lattices as well as orthocomplemented lattices are B-lattices. On the other hand, a B-lattice is not necessarily Boolean or orthocomplemented, although a distributive B-lattice is a Boolean lattice. It is shown later that a matroid (geometric) lattice is also a B-lattice. Naturally, our results include the lemma of Banaschewski [ 1, Lemma 4], by which the lattice of the subspaces of a vector space is a B-lattice. It should be emphasized that a B-function is supposed…

Three-dimensional Hall effect accelerometer for recording head movements of freely moving laboratory animals

1991

A Hall effect device was constructed for a measurement of head movements in three spatial dimensions during classical conditioning experiments in cats. A Hall sensor was used to detect movements of a magnetic fragment floating in a small (15 x 15 mm) cube. The magnetic fragment was kept in the centre of the sealed cube with a thin coil spring which was filled with thin oil for damping excessive afteroscillations. A comparison of this device to a commercial accelerometer showed that the accuracy of the Hall device is sufficient for the movement recordings and that the device is sensitive also to slowly accelerating movements. The construction is compact and can be easily mounted, for example…

Surface-state electrons on a hydrogen film. 1. Annealing of the film

1991

We have investigated the surface of thin films (thickness ∼2 µm) of solid H2 between 1.5 and 4.2 K by measuring the ac conductivity of surface-state electrons (SSE). The films were prepared on a glass substrate by quench condensation at 1.5 K and were therefore initially strongly disordered. In fact the surface of the virgin films before any heat treatment was so rough that no current due to SSE could be observed. Annealing the films decreased the surface roughness and gave rise to a thermal-activation-type temperature dependence of the SSE conductivity. By proper heat treatment up to 8 K the activation energy could be reduced to 10kB.

N-benzoylindole-2,3-quinodimethane: Diels-Alder reactivity and synthetic applications for [b]annellated indoles

1991

Abstract The Diels-Alder reactivity of in situ generated N -benzoylindole-2,3-quinodimethane has been expanded considerably to include reactions with carbon- and hetero-dienophiles which furnish a variety of [ b ]annellated indoles as well as functionalized and annellated carbazoles. The frontier molecular orbital theory was found to be a useful model for the prediction of the experimental results under consideration of reactivity aspects.

“The Civil War and the Call for Southern Literature”

1991

International audience

Thyrotropin-releasing hormone has stimulatory effects on ventilation in humans

1991

Thyrotropin-releasing hormone (TRH) stimulates pituitary thyrotropin synthesis and release and also regulates autonomic nervous system functions by acting as a neuromodulator and neurotransmitter. In experimental animals a stimulation of ventilation by thyrotropin-releasing hormone was shown when applied at central nervous system sites that affect respiratory motor output. It was the goal of our study to investigate the respiratory properties of thyrotropin-releasing hormone on basal and stimulated (i.e. CO2-rebreathing) conditions following systemic thyrotropin-releasing hormone application in healthy humans. Thyrotropin-releasing hormone (200 micrograms, 400 micrograms intravenous) initia…

Light-induced ionic processes in optical oxide glasses

1991

Abstract The density of optical glasses is changed by the influence of light capable of generating color centers in these materials. Such defect generation is not only an electronic process, but an atomic displacement is also necessary. The strong localization of electronic and vibrational excitations in the glass network leads to the high efficiency of sub-threshold defect generation. Secondary ionic processes lead to the changes of basic glass properties (light refractive index, density, mechanical strength, etc.); thus, it is possible to use optical glasses as light detectors for appropriate wavelengths.

Hermite interpolation: The barycentric approach

1991

The barycentric formulas for polynomial and rational Hermite interpolation are derived; an efficient algorithm for the computation of these interpolants is developed. Some new interpolation principles based on rational interpolation are discussed.

Evaluating the motivating environment in Finland compared to the United States—a survey

1991

A comparison was made of perceptions of IS personnel—especially of analysts, programmers and managers—on factors relating to motivation and goal setting in Finland and the United States. The JDS/DP, a modification of the job diagnostic survey instrument, was used to collect data in these locations. The survey covered a statistically unbiased and representative sample in both countries. The results indicated significant similarities between the two populations. Not only were individual characteristics of growth-need and social-need similar, but their perception of job-related variables were also quite similar. The only differences found were in the job satisfaction of technical experts and i…

Indecomposable modules over the Virasoro Lie algebra and a conjecture of V. Kac

1991

We consider a class of indecomposable modules over the Virasoro Lie algebra that we call bounded admissible modules. We get results concerning the center and the dimensions of the weight spaces. We prove that these modules always contain a submodule with one-dimensional weight spaces. From this follows the proof of a conjecture of V. Kac concerning the classification of simple admissible modules.

Characterisation of the glycosidic linkage by infrared and Raman spectroscopy in the C-H stretching region: α,α-trehalose and α,α-trehalose-2,3,4,6,6…

1991

Abstract I.r. and Raman spectra of solid α,α-trehalose and α,α-trehalose- 2,3,4,6,6-d 10 in the C-H and C-D stretching regions are recorded. The experimental data are reproduced satisfactorily by normal co-ordinate and i.r. absorption intensity calculations which take into account the specific interactions of each C-H hydrogen with nearby oxygen lone-pairs. The relevance of the region 2800–3000 cm −1 in α,α-trehalose- 2,3,4,6,6-d 10 for the study of the conformational properties of the inter-glycosidic linkage is discussed.

false

1991

Tracer diffusion coefficients D* of both components were measured in mixtures of polystyrene (PS) and polymethylstyrene (PMS), a random copolymer from 60 wt.-% of m-methylstyrene and 40 wt.-% of p-methylstyrene. The results are interpreted in terms of the free-volume theory which yields master curves even for “asymmetric” mixtures of oligomer and polymer chains, if D* is drawn versus the distance from the glass transition temperature, T–Tg. Whereas D* was measured by the forced Rayleigh scattering technique, we also studied photon correlation spectroscopy in these mixtures and observed “slow modes” with decay constants that correspond to diffusion coefficients 2–3 decades smaller than the i…

Die Perforation bei Morbus Crohn als Komplikation in der Schwangerschaft

1991

The manifestation of Crohn's disease with perforation in pregnancy has been described in one case only. In our case, a 25-year-old woman in the 28th week of pregnancy was admitted to our hospital with signs of an acute abdomen. Due to deterioration of the maternal and foetal situation, the child was delivered by a Caesarean section. Subsequently, exploration of the abdomen showed an ileum perforation with diffuse fibrinous peritonitis. In this case, the definitive diagnosis could not be made prior to laparotomy. The aim of surgical therapy in such cases should be the limited resection with end to end anastomosis. In diffuse peritonitis, discontinuous resection and secondary reconstruction a…

Calculation of the kaon B parameter using strictly local sum rules

1991

The kaon B-parameter is computed in the framework of strictly local QCD sum rules for a threepoint function involving pseudoscalar currents. As an application of these sum rules we derive a low energy formula for the B-parameter. We show that strictly local QCD sum rules yield more reliable results than other QCD sum rules, since they need less phenomenological information and do not suffer from stability problems. Our result for the B-parameter isB=0.74±0.17.

Compared effects of synthetic and natural bile acid surfactants on xenobiotic absorption I. Studies with polysorbate and taurocholate in rat colon

1991

Some expected differences between synthetic and natural bile acid surfactants relative to their influences on xenobiotic absorption are briefly outlined on the basis of literature data. Then, experimental work is presented which shows that these differences exist and that they can be even more relevant than suspected. Absorption tests were developed in rat colon in situ with polysorbate (synthetic) and sodium taurocholate (natural) surfactants, using a homologous series of phenylalkylcarboxylic acids as test compounds. At the critical micelle concentration (CMC), the two previously reported actions of synthetic surfactants on xenobiotic absorption (i.e. the increase in absorbing membrane po…

Candida albicans mycelial wall structure: supramolecular complexes released by zymolyase, chitinase and beta-mercaptoethanol.

1991

Different techniques released from the wall of Candida albicans mycelial cells high molecular weight mannoprotein materials with different levels of complexity. SDS solubilized among others one protein of 180 kDa which reacted with a monoclonal antibody (MAb) specific of a O-glycosylated protein secreted by regenerating mycelial protoplasts [Elorza et al. (1989) Biochem Biophys Res Commun 162:1118-1125]. Zymolyase, chitinase and beta-mercaptoethanol, released different types of high molecular highly polydisperse mannoprotein materials (greater than 180 kDa) that also reacted with the same MAb. These materials had N-glycosidically linked sugar chains, in addition to the O-glycosidically bond…

Der Effekt von Neostigmin an der motorischen Endplatte beim Intermediärsyndrom der Alkylphosphatvergiftung

1991

A patient with severe organophosphate intoxication received Neostigmine 1 mg IV during the intermediate syndrome. This dose resulted clinically and neurophysiologically in a marked deterioration of neuro-muscular transmission. This effect of neostigmine on the neuromuscular block during the intermediate syndrome (deterioration) differs from its effect on a similar pattern (improvement), which is seen in the delayed neuropathy following organophosphate exposure. The administration of therapeutic doses of cholinesterase inhibitors in patients with a reduced safety margin due to inhibition of endplate acetylcholinesterase may be dangerous.

Significant correlations between certain spectra of atmospherics and different biological and pathological parameters.

1991

Atmospherics are very short naturally occurring electromagnetic impulses of between 4 and 50 kHz. In this review we summarize our results concerning the correlations between certain spectra of atmospherics and several biological and pathological parameters.

Früh- und Spätergebnisse der perkutanen transluminalen Angioplastie (PTA) beim Diabetiker

1991

Results of 127 iliac and femoropopliteal transluminal angioplasties in 97 diabetic patients are presented. Patients who had undergone iliac (n = 70), femoral (n = 41), and popliteal (n = 16) angioplasties for stenoses up to 15 cm long were followed up for 6-60 months. In diabetic patients presenting with only claudication or adequate runoff, the 5-year iliac patency rate was 76% and the femoral patency rate was 60%; these results were comparable with those found in non-diabetic patients. For limb salvage, 3-year patency rates were 66% for iliac, 37% for femoral, and 37% for popliteal angioplasties, and 5-year patency rates were 29% for iliac, 7% for femoral, and 0% for popliteal angioplasti…

Multinuclear magnetic resonance study of 1,3,3-trimethylbicyclo [2.2.1]heptan-2-one (fenchone) oxime, its five monochloro derivatives and a dehydroch…

1991

Fenchone oxime, 5-exo-chlorofenchone oxime, 6-exo-chlorofenchone oxime, 7-anti-chlorofenchone oxime, 8-chlorofenchone oxime, 9-chlorofenchone oxime and a dehydrochlorination product of 10-chlorofenchone oxime were synthesized from fenchone and the corresponding chlorofenchones. The 1H, 13C and 17O NMR spectra of the oximes and the dehydrochlorination product were recorded. The NMR data were compared with the corresponding parameters obtained earlier for fenchone and monochlorofenchones in order to determine the differences between the carbonyl and oxime substituents from the NMR spectroscopic point of view, and to assign the stereochemistry of the oxime group. This stereochemistry could not…

Simulation of Dense Polymer Systems in Two and Three Dimensions

1991

Dense polymer systems are modeled by self- and mutually avoiding walks on lattices. Both simple models where the step length is one lattice spacing and more complicated models where the step length is distinctly longer and may fluctuate (“bond fluctuation model”) are discussed, and it is shown that the computer simulation of such models gives useful insight to understand the thermodynamic phase behavior and the relaxational dynamics of dense polymer solutions and polymer melts. The huge demands in computing power needed for a successful simulation of such systems can be covered by parallel computers such as the multitransputer facility of the University of Mainz.

Investigations of TiO2 films deposited by different techniques

1991

High refractive TiO2 films deposited by reactive electron beam evaporation, reactive ion plating and dip coating have been characterized by optical spectroscopy, electron spectroscopy for chemical analysis, Rutherford backscattering spectroscopy, nuclear reaction analysis and Raman spectroscopy. The spectral refractive index n exhibits a strong dependence on the deposition conditions. These findings will be connected to variations in density, stoichiometry, hydrogen content (H2O) and binding structure of the layers. A strong correlation is found between optical quantities and microscopic properties of TiO2 films.

Quantum Monte Carlo Simulations of Models Related to High-Tc Superconductivity on a Transputer Network

1991

Much of the insight into the low temperature behaviour of two-dimensional quantum antiferromagnets has been recently obtained by extensive Monte Carlo. These models are relevant in the study of the magnetic behaviour of high Tc compounds containing copper-oxide layers. While of little technical importance, the physical properties of these models are certainly important for the understanding of the new type of behaviour that leads to superconductivity under certain conditions.

Correlations of female steroid hormone receptors with histologic features in meningiomas.

1991

A series of 39 samples were obtained from meningiomas in 28 patients in order to investigate the relationships of the oestrogen receptor (OER) and progesterone receptor (PR) with the tumoural subtype and some histological features. Twenty-one samples were positive (greater than 10 fmole/mg protein), 7 were OER-PR-negative, and 1 was positive in both receptors. Twenty-two samples were considered as syncitial, 7 transitional, 7 fibroblastic and 3 angioblastic. The histological subtype was not found to be significantly related to the presence or absence of PR. Relations were not observed between the progestin receptor and the following histological parameters: cellular pattern, cell density, n…

Analysis of the polypeptide composition of the cell walls of Neurospora crassa. Similarities with the proteinaceous material secreted by the slime va…

1991

The polypeptide composition of cell walls from the wild-type strain of Neurospora crassa is compared with that of the proteinaceous extracellular coat (PEM) secreted by the slime strain of this fungus. Analyses included determination of the polypeptide pattern by polyacrylamide gel electrophoresis and blotting followed by staining with Concanavalin A and antibodies raised against the overall antigenic components present in either (whole cell walls or PEM) structure. A complex protein assortment was found associated to the walls of the wild type strain. The similarities observed between the polypeptide patterns of the cell walls and PEM, in addition to the immunological cross-reactivity exhi…

Precipitation of slightly soluble silver salts in reversed AOT micelles: Calorimetric investigation

1991

The enthalpies of precipitation, of AgCl, Agl, Ag2S and silver tetraphenylborate (AgTPB) in water containing reversed sodium bis(2-ethylhexyl) sulfosuccinate (AOT) micelles as a function of the molar concentration ratio R (R=[water]/[AOT]) at various concentrations of AOT and reagent salts, were measured by a calorimetric technique. The molar enthalpies of precipitation are independent of the surfactant concentration but are dependent on the concentration of the reagent salts and the R value. The molar enthalpies for the same processes in bulk water are not approached even at the highest R value. Effects due to the smallness of the microcrystals and to the interactions between ions and mice…

Diethylene glycol (DEG)-associated myocardial changes: a pilot investigation of chronic intoxication in guinea-pigs.

1991

The myocardium of guinea pigs fed on sublethal doses of diethylene glycol (DEG) over a period of 2–11 days was examined for microscopical and ultrastructural changes. Coagulative myocytolysis and loss of myofibrils, not observed in the controls, was patchily distributed throughout the myocardium. The accompanying ultrastructural features included swelling, pleomorphism and hyperplasia of mitochondria with an associated distension of the interfibrillary spaces and a displacement, distortion and rupture of adjacent myofibrils.