Escherichia coli possesses two homologous anaerobic C4-dicarboxylate membrane transporters (DcuA and DcuB) distinct from the aerobic dicarboxylate tr…

1994

The nucleotide sequences of two Escherichia coli genes, dcuA and dcuB (formerly designated genA and genF), have been shown to encode highly homologous products, M(r) 45,751 and 47,935 (434 and 446 amino acid residues) with 36% sequence identity (63% similarity). These proteins have a high proportion (approximately 61%) of hydrophobic residues and are probably members of a new group of integral inner membrane proteins. The locations of the dcu genes, one upstream of the aspartase gene (dcuA-aspA) and the other downstream of the anaerobic fumarase gene (fumB-dcuB), suggested that they may function in the anaerobic transport of C4-dicarboxylic acids. Growth tests and transport studies with mut…

Helium and CO2 soil gas emission from Santorini (Greece)

1994

Soil gas investigation is a useful tool to detect active faults. The sudden appearance of soil gas anomalies in zones of deep-reaching faults represents a promising potential precursor of earthquakes and volcanic eruptions. In volcanic areas the development of soil gas monitoring techniques is particularly important, as they can represent, together with remote sensing techniques, the only geochemical methods that can be safely applied during volcanic unrest, when it becomes impossible or too dangerous to sample crater fumaroles. A soil gas survey was carried out in June 1993 at the main island of Thera, in the Santorini volcanic complex. CO2 flux and CO2 and helium concentrations were measu…

Electrostatic contribution to the interaction of α, β poly (N-hydroxyethyl)-DL-aspartamide with sodium dodecylsulfate micelles

1994

The enthalpic effect due to the interaction between α, β poly(N-hydroxyethyl)-DL-aspartamide (PHEA) and sodium dodecylsulfate (SDS) in aqueous solutions as a function of the surfactant concentration was measured by the calorimetric technique at various NaCl concentrations. A marked influence of the added electrolyte on the PHEA-SDS interaction was observed. An analysis of the experimental enthalpies allows to estimate the electrostatic and the hydrophobic contributions to the enthalpy of interaction between PHEA and SDS micelles. The results were rationalized in terms of effects due to the screening of the charges residing on PHEA and SDS micelles.

Metal ion beams from an ECR ion source using volatile compounds

1994

Abstract A new MIVOC method (Metal Ions from Volatile Compounds) at an ECR ion source gives a means to produce highly charged metal ion beams at room temperature conditions. Chemical compounds containing metallic atoms are utilized. The compound has to fulfill the two basic requirements: Vapour pressure of the compound is relatively high at room temperature. Evaporation and diffusion of the compound into the source take place without dissociation of the molecule. Up to present metal ion beams from iron and nickel compounds have been produced. The maximum currents of 56Fe9+ and 58Ni10+ from natural elements were 23.9 μA and 18.7 μA, respectively. First measurements have demonstrated the abil…

Major histocompatibility complex class II binding site for streptococcal pyrogenic (erythrogenic) toxin A.

1994

Streptococcal pyrogenic exotoxin A (SPEA) is an important pathogenicity factor of group A streptococci. It is a member of the family of „superantigens” produced by Staphylococcus aureus and Streptococcus pyogenes and its T lymphocyte stimulating activity is involved into the pathogenesis of certain diseases caused by pyogenic streptococci. In this study we have produced and characterized recombinant SPEA molecules in Escherichia coli. These molecules are indistinguishable from natural SPEA in both T cell stimulatory and HLA class II binding activities. Human class II molecules are more efficient than mouse class II molecules in presenting SPEA to T cells. In binding tests to major histocomp…

Posttranslational processing of human alpha 2-HS glycoprotein (human fetuin). Evidence for the production of a phosphorylated single-chain form by he…

1994

alpha 2-HS glycoprotein (alpha 2-HS) is a major protein occurring in human blood and calciferous tissues. Due to extensive sequence identity, alpha 2-HS has been grouped with the fetuins, a family of proteins that occur in fetal plasma in high concentrations. Native alpha 2-HS undergoes a series of posttranslational modifications including proteolytic processing, multiple N-glycosylations and O-glycosylations, and sulfation of the carbohydrate side chains. Various two-chain forms of alpha 2-HS have been prepared from human plasma, however, the single-chain precursor has not yet been isolated. Here, we have studied the biosynthesis of alpha 2-HS by a human hepatoma cell line, HepG2. We demon…

Expression of nicotinic acetylcholine receptors in the rat superior cervical ganglion on mRNA and protein level.

1994

The expression of nicotinic acetylcholine receptors (nAChR) in the rat superior cervical ganglion was investigated by Western blotting, immunohistochemistry and non-radioactive in situ hybridization applying probes for the alpha 4-1 and beta 2 subunit mRNA. Immunoblot analysis of homogenized ganglia using the anti-nAChRs antibody WF6 revealed a labeled protein band of apparent molecular weight of 40 kDa which is typical for the alpha subunit of nAChRs. Applying double-labeling immunofluorescence with antibodies against tyrosine hydroxylase, nAChR-like molecules were identified in most postganglionic neurons and in a subpopulation of small intensely fluorescent (SIF) cells. alpha 4-1 and bet…

Pleomorphic pineocytoma with extensive neuronal differentiation: report of two cases

1994

Two pineal parenchymal tumors are presented, arising in a 54-year-old man and a 72-year-old woman; respectively. They showed isomorphic, cellular areas of small cells, often with characteristic pineocytomatous rosettes, and of medium-sized cells, as well as less cellular regions with highly pleomorphic, often ganglioid large cells. Immunohistochemistry disclosed extensive neuronal differentiation. There was intense positivity for neurofilament protein and microtubule-associated protein 2 in the pleomorphic areas and more variable expression in the isomorphic regions. Diffuse synaptophysin positivity was seen, accentuated along the borders of pleomorphic cells and in the rosettes, as well as…

The origin of the intrinsic 1.9 eV luminescence band in glassy SiO2

1994

Abstract The current controversy over the nature of the centers giving rise to the 1.9 eV photoluminescence (PL) band (the R-band), the suggested defect models and the relevant experimental data are briefly reviewed. The luminescence emission, excitation and polarization spectra of neutron-irradiated synthetic silica were studied between 6 and 300 K using site-selective dye-laser and Ar ion laser excitation. Resonant zero-phonon lines (ZPL) were observed below 80 K both in luminescence emission and excitation spectra in the 1.9–2.1 eV region. A vibration line in emission spectra 890 cm−1 below the ZPL energy is attributed to the symmetric stretching vibration of the silicon-non-bridging oxy…

General biological properties of antioxidant permeatoxins and their influence on natural and model membranes

1994

Determination of catecholamines in urine by micellar liquid chromatography with coulometric detection

1994

The determination of catecholamines by HPLC with a sodium dodecyl-sulphate (SDS), micellar mobile phase on a C18 column and with coulometric detection was studied. The eluate was conditioned at +0.25 and +0.00 V, and the current at −0.16V was recorded. A previously developed model which describes the chromatographic behaviour of solutes in HPLC with hybrid, micellar mobile phases was used to optimize the SDS and ethanol concentrations. A mobile phase of 0.15M SDS in a phosphate buffer of pH 3.4 and without ethanol is recommended. The limits of detection were 0.4–0.7 ng ml−1. The procedure was applied to the determination of unconjugated L-dopa, norepinephrine and dopamine in urine. Direct i…

Three-dimensional imaging of cardiac mass lesions by transesophageal echocardiographic computed tomography.

1994

Three-dimensional echocardiography is a new imaging technique that allows more realistic visualization of cardiac morphology. This study presents data about the diagnostic potentials of this technique concerning cardiac mass lesions, as well as its feasibility in clinical application. After the conventional investigation, multiple cross-sectional images were obtained during automatic forward advancement of a monoplane transducer mounted on a transesophageal probe. Three-dimensional reconstruction and volume determination were performed off line. Twenty-four patients were studied. In 14 cases results of echocardiographic computed tomography (echo-CT) were compared with those of monoplane/bip…

Precision Laser Spectroscopy of the Ground State Hyperfine Splitting of HydrogenlikeBi82+209

1994

The first direct observation of a hyperfine splitting in the optical regime is reported. The wavelength of the $M1$ transition between the $F=4$ and $F=5$ hyperfine levels of the ground state of hydrogenlike $^{209}\mathrm{Bi}^{82+}$ was measured to be ${\ensuremath{\lambda}}_{0}=243.87(4)$ nm by detection of laser induced fluorescence at the heavy-ion storage ring ESR at GSI. In addition, the lifetime of the laser excited $F=5$ sublevel was determined to be ${\ensuremath{\tau}}_{0}=0.351(16)$ ms. The method can be applied to a number of other nuclei and should allow a novel test of QED corrections in the previously unexplored combination of strong magnetic and electric fields in highly cha…

L'apport des restes animaux à l'analyse spatiale des sites fossoyés du second âge du Fer

1994

National audience

Correlated response of in vitro regeneration capacity from different source of explants inCucumis melo.

1994

The variation among and within different populations of the regeneration ability from leaf, cotyledon and hypocotyl explants has been studied. A control population and two lines selected by their regeneration capacity from leaf explants were used. Significant differences among the plants of the control population,for the organogenic response, were detected. The regeneration capacity varies depending on the type of explant. Selection in order to improve the regeneration frequency from leaf explants also raises the organogenic response in the other explant types. This result suggests the presence of a partial common genetic system controlling the regeneration frequency of the diverse types of…

Quantum deformation of the Poincare supergroup and kappa -deformed superspace

1994

The classical $r$-matrix for $N=1$ superPoincar{\'e} algebra, given by Lukierski, Nowicki and Sobczyk is used to describe the graded Poisson structure on the $N=1$ Poincar{\'e} supergroup. The standard correspondence principle between the even (odd) Poisson brackets and (anti)commutators leads to the consistent quantum deformation of the superPoincar{\'e} group with the deformation parameter $q$ described by fundamental mass parameter $\kappa \quad (\kappa^{-1}=\ln{q})$. The $\kappa$-deformation of $N=1$ superspace as dual to the $\kappa$-deformed supersymmetry algebra is discussed.

Geometrical volume effects in the computation of the slope of the isgur-wise function

1994

We use a method recently suggested for evaluating the slope of the Isgur-Wise function, at the zero-recoil point, on the lattice. The computations are performed in the quenched approximation to lattice QCD, on a $24^3 \times 48$ lattice at $\beta=6.2$, using an $O(a)$-improved action for the fermions. We have found unexpectedly large finite-volume effects in such a calculation. These volume corrections turned out to be purely geometrical and independent of the dynamics of the system. After the study of these effects on a smaller volume and for different quark masses, we give approximate expressions that account for them. Using these approximations we find $\xi^\prime(1)=-1.7 \pm 0.2$ and $\…

DISORDERING MECHANISMS OF THE Cu(110) SURFACE

1994

We review recent theoretical work on the various disordering mechanisms of the Cu(110) surface. In these studies the properties of the surface, from the onset of enhanced anharmonicity in surface vibrations up to bulk melting point T M , have been studied using molecular dynamics and lattice-gas Monte Carlo methods with many-body interactions derived from the effective medium theory. Well after the onset of enhanced out-of-plane surface vibrations, clustering of surface defects is found to induce a roughening transition at T≈0.81T M , and surface premelting is found to occur at T≈0.97T M . These results suggest, that these transitions can both appear at Cu(110). The general picture of diso…

Synthese von Desoxy-Sialyl-Lewisx-Analoga, potentiellen Selectin-Antagonisten

1994

Control of single-electron tunneling by surface acoustic waves.

1994

Foreground Contributions to 0.2-2 Degree CMB Anisotropies

1994

We examine the extent to which galactic and extragalactic foregrounds can hamper the detection of primordial Cosmic Microwave Background (CMB) anisotropies. We limit our discussion to intermediate angular scales, $10^{\prime}\lsim \theta \lsim 2^{\circ}$, since many current as well as future experiments have been designed to map CMB anisotropies at these angular scales. In fact, scales of $\gsim 10^{\prime}$ are of crucial importance to test both the conditions in the early Universe and current theories of the gravitational collapse.

Three-jet production at LEP and the bottom quark mass

1994

We consider the possibility of extracting the bottom quark mass from LEP data. The inclusive decay rate for $\zbb +\cdots$ is obtained at order $\as$ by summing up the one-loop two-parton decay rate to the tree-level three-parton rate. We calculate the decay width of the $Z$-boson into two and three jets containing the $b$-quark including complete quark mass effects. In particular, we give analytic results for a slight modification of the JADE clustering algorithm. We also study the angular distribution with respect to the angle formed between the gluon and the quark jets, which has a strong dependence on the quark mass. The impact of higher order QCD corrections on these observables is bri…

Reconciling Cold Dark Matter with COBE/IRAS Plus Solar and Atmospheric Neutrino Data

1994

We present a model where an unstable MeV Majorana tau \neu can naturally reconcile the cold dark matter model (CDM) with cosmological observations of large and small scale density fluctuations and, simultaneously, with data on solar and atmospheric neutrinos. The solar \neu deficit is explained through long wavelength, so-called {\sl just-so} oscillations involving conversions of \ne into both \nm and a sterile species \ns, while atmospheric \neu data are explained through \nm to \ne conversions. Future long baseline \neu oscillation experiments, as well as some reactor experiments will test this hypothesis. The model is based on the spontaneous violation of a global lepton number symmetry …

Effect of vitamin B6 on lipid peroxidation associated with exhaustive exercise in male trained rats

1994

International audience

Measurement of the proton-antiproton total cross section at the SppS collider by a luminosity dependent method

1994

Abstract The proton-antiproton total cross section was measured at the center-of-mass energy of s = 541 GeV at the S p pS at CERN using a luminosity dependent method. The result σtot=63.0±2.1 mb is in agreement with the luminosity independent measurement performed earlier by the UA4 Collaboration.

Les détecteurs de gaz en utilisation quantitative

1994

National audience

Flavour sensors: the PPM barrier is broken

1994

National audience

Compact dielectric reflective elements II Multichannel filter of closely spaced spectral bands

1994

The optical design of an interference wedge filter providing the simultaneous separation of a number of closely spaced spectral bands is studied. Multiple reflections of the incident collimated beam within the wedge are initiated, each of them characterized by a different angle of incidence and consequently by specific spectral parameters of the transmitted band. Model calculations based on the measured angular dependences of filter transmission parameters have been performed. The design is proposed for applications in optical communications (wavelength division demultiplexing), analytical spectroscopy (minipolychromators), color analysis, and similar areas.

Platelet aggregation, ATP release and cytoplasmic Ca2+ movement: the effects of cloricromene.

1994

A placebo-controlled, double-blind, randomized, cross-over study was performed in 24 healthy volunteers. 12 volunteers received Cloricromene (100mg gastroresistant capsules twice a day) for 7 days, the other volunteers received identical placebo capsules. Subsequently, after a 7-day wash-out period, at day 15, each subject received the other treatment. Blood samples were taken on days 1 and 15 (1st day of each treatment) as well as on days 7 and 21 (7th day of each treatment) before the morning drug administration and 2 and 4 hours later. Platelet aggregation and ATP secretion were studied in whole blood (WB) using ADP and collagen as stimulating agents. Ca2+ fluxes were studied in aequorin…

Three-Dimensional Surface Display in Blood Pool Gated SPECT

1994

In 14 patients (4 in good health and 10 with coronary heart disease) a blood pool gated single photon emission computed tomography (SPECT) was executed. The transaxial slices of the cardiac blood pool were reconstructed. A three-dimensional surface display was employed for the analysis of the tomographic data. A fixed distance, a fixed threshold (50%), and some different planes of view were employed. The test permitted visualiza tion of the ventricular and the atrial movements in all patients. The right ventricle was clearly seen in the right anterior oblique plane of view. The aortic beating was seen. In normal patients the left ventricle, clearly seen in left anterior oblique plane, shra…

Geodesics on spaces of almost hermitian structures

1994

A natural metric on the space of all almost hermitian structures on a given manifold is investigated.

Are morphology and composition of gallstones related? An x-ray diffraction study

1994

Abstract An x-ray diffractometric technique was used to study the crystalline composition of gallstones removed during surgery from 106 patients. Monohydrate cholesterol was found in the stones of 70 (66%) patients, either alone (33%) or in association with calcium salts (33%). The anhydrous form of cholesterol was found in the stones of 28 (26%) patients, either alone (10%) or in association with calcium salts (16%). These salts (vaterite, aragonite, and calcite) were found in 50% of cases in varying amounts (from 12% to 15% of the stone weight). Eight stones contained no cholesterol: 4 showed an amorphous pattern and 4 were composed of calcium carbonate salts. In 7 of 8 patients with bile…

The real part of the elastic-scattering amplitude at the $$S\bar ppS$$ and predictions at LHC and SSCand predictions at LHC and SSC

1994

A precise measurement of\(\bar pp\) elastic scattering in the Coulomb strong-interaction interference region was performed at the CERN\(S\bar ppS\) Collider at a centre-of-mass energy of 541 GeV. The ratio of the real-to-imaginary part of the forward elastic-scattering amplitude was found to be ρ=0.135±0.015. The slope of the exponential fall-off of the strong-interaction part was also measured to beb=15.5±0.1 GeV−2. Using this new result, an overall fit to the data on the total cross-section and on the real part for\(\bar pp\) and pp was performed using dispersion relations. Numerical predictions are presented for total cross-sections at LHC and SSC energies.

Abstracts from the sixth meeting of the international association of pancreatology, November 2–4, 1994, Chicago, IL

1994

Diterpenoids fromStachys mucronata

1994

Structural mannoproteins released by β-elimination fromCandida albicanscell walls

1994

Abstract Mild alkaline solutions (β-elimination), after removing the non-covalently bonded wall materials by hot SDS, released 13% and 26% of remaining wall proteins from mycelial and yeast cells of Candida albicans, respectively. When the β-elimination was carried out after digestion of the walls with chitinase, four-fold more proteinaceous materials were released from mycelium and a similar amount in yeast walls. The solubilized materials were shown to be highly polydisperse, and endo-glycosidase H reduced their polydispersity and molecular masses, revealing different electrophoretic patterns in yeast and mycelial cell walls. The solubilized mycelial proteins carried N-glycosidic sugar ch…