X-ray-absorption study of rheniumL3andL1edges inReO3: Multiple-scattering approach

1993

We present ab initio calculations of x-ray-absorption fine structure for the Re L 3 and L 1 edges in crystalline ReO 3 based on an exact curved-wave multiple-scattering approach. Good agreement between theoretical and experimental data has been found for both edges. We show that, as expected, the contribution of multiple-scattering signals from linear chains, like Re-O-Re and O-Re-O, is very large both in the L 3 - and L 1 -edge spectra due to the strong focusing effect caused by the middle atom

Simultaneous substitution of bridging acetate groups and reversible RhC bond cleavage in [Rh2(O2CCH3)3-{(C6H4)PPh2}(HO2CCH3)2] in the presence of CF…

1993

Abstract The reaction of the monometallated compound [Rh2(O2CCH3)3 {(C6H4)PPh2}(HO2CCH3)2] (1) with CF3CO2H at room temperature yields [Rh2(O2CCF3)3{(C6H4)PPh2}(HO2CCF3)2] (3) as the only isolable product. Compound 3 has been characterized by X-ray methods. 3 crystallizes in the space group P21 / n. It contains three trifluoroacetate groups bridging a Rh4+2 unit with a RhRh bond distance of 2.438(1) Ă; the fourth bridging ligand is a triphenylphosphine metallated at one of the ortho positions. Two molecules of trifluoroacetic acid occupy the axial coordination positions. In addition to the substitution of acetate groups, reversible electrophilic RhC bond activation is observed.

Function of Dipeptidyl Peptidase IV (CD26, Tp103) in Transfected Human T Cells

1993

CD26 (Tp103) is a proteolytic enzyme (dipeptidyl peptidase IV) expressed on the T cell surface that defines an alternative activation signal for human T lymphocytes. It is absent from or present in only low amounts on resting T cells but it is expressed strongly after activation. Crosslinking of CD26/Tp103 via the monoclonal antibody CB.1 triggers functional activities in preactivated T cells. To study the molecular requirements for T cell activation via CD26 we transfected a cDNA encoding CD26 into several CD26-negative cells. In Jurkat T cell leukemia cells that normally do not express the CD26 antigen, the transfected CD26 molecule is functional because the monoclonal antibody CB.1 induc…

Modulation by 5-HT3 and 5-HT4 receptors of the release of 5-hydroxytryptamine from the guinea-pig small intestine.

1993

The effects of agonists and antagonists of 5-hydroxytryptamine (5-HT) receptors on the release of endogenous 5-HT from enterochromaffin cells were studied in the vascularly perfused isolated guinea-pig small intestine. The experiments were done in the presence of tetrodotoxin in order to exclude a neuronally mediated influence on 5-HT release. The 5-HT3 receptor agonist 2-methyl-5-HT increased 5-HT release, and this effect was antagonized by 1 nmol/l tropisetron. Nanomolar concentrations of tropisetron, MDL 72,222 and granisetron decreased 5-HT release. Ondansetron (0.1 and 1 mumol/l) did not modify 5-HT release. 5-Methoxytryptamine, BIMU8 and cisapride concentration-dependently inhibited 5…

WEAR MECHANISM OF CERAMIC TOOLS

1993

Abstract Cutting tests were performed using ceramic cutting tools under continuous cutting conditions. The tests were carried out on AISI 1040 steel, with cutting speeds ranging from 5 to 11 m s −1 . The wear mechanism was investigated for both crater and flank. Alumina-toughened zirconia of submicron grain size showed the best wear resistance. Alumina with TiC, TiN and ZrO 2 inclusions exhibited a wear resistance a little lower than the above-mentioned materials. Low chemical stability seems to be the reason for the poor performances of the silicon carbide whiskers-reinforced alumina, silicon nitride and the tungsten carbide inserts.

Book Review: Properties of Chemically Interesting Potential Energy Surfaces.(Series: Lecture Notes in Chemistry, Vol. 56.) By D. Heidrich, W. Kleisch…

1993

Quantitative characterization of antigens using monoclonal antibody reactivities

1993

A multipurpose program that empirically relates antigenic reactivities with monoclonal antibodies (MAbs) to genetic distances is presented. The program uses a set of known genetic pairwise distances to weigh each MAb depending on its capacity to define groups of taxonomically related antigens. This allows highly accurate identification and classification of unknown antigens. Also, the weights obtained constitute a quantitative measure of epitope conservation and can be used for improved vaccine design. © 1993 Oxford University Press.

Neuromuscular fatigue and recovery in male and female athletes during heavy resistance exercise.

1993

To examine neuromuscular fatigue and recovery ten male and nine female athletes performed a strenuous heavy resistance exercise protocol. The subjects strained their leg extensor muscles with the same maximal relative intensity by performing one maximal squat-lift with a load of 100% of 1 RM (one repetition maximum) 20 times (20 x 1 x 100%). Maximal voluntary neural activation (integrated EMG), maximal bilateral isometric force, force-time and relaxation-time curves of the leg extensor muscles were measured before and immediately after the exercise session as well as after resting for 1 hour, 2 hours, 1 day and 2 days. The session resulted in considerable gradual decreases in maximal force …

Personality and movie preferences: A comparison of American and German audiences

1993

Abstract The impact of personality type (extraversion, neuroticism, psychoticism) and culture (American, German) on preferences for contemporary movies was explored. Consistent with theoretical expectations, the findings revealed that movie preferences were mediated by both the psychoticism and extraversion personality types and by an interaction between psychoticism by culture.

Gypsy homologous sequences in Drosophila subobscura (gypsyDS).

1993

Characterization of sequences homologous to the Drosophila melanogaster gypsy transposable element was carried out in Drosophila subobscura (gypsyDS). They were found to be widely distributed among natural populations of this species. From Southern blot and in situ analyses, these sequences appear to be mobile in this species. GypsyDS sequences are located in both euchromatic and heterochromatic regions. A complete gypsyDS sequence was isolated from a D. subobscura genomic library, and a 1.3-kb fragment which aligns with the ORF2 of the D. melanogaster gypsy element was sequenced. Comparisons of this sequence in three species (D. subobscura, D. melanogaster, and D. virilis) indicate that th…

Protonation thermodynamics of 2,2'-bipyridyl in aqueous solution. Salt effects and weak complex formation

1993

Abstract Protonation constants of 2,2'-bipyridyl (bipy) have been determined potentiometrically, using (H + )-glass electrode, in different aqueous media (alkali and alkaline earth chlorides, tetramethylammonium chloride and tetramethylammonium iodide) at different temperatures and ionic strengths. The differences in log K H values are explained using a complex formation model. Formation thermodynamic parameters are given.

Binding and isomerization energies for the Cu/CN and Cu(I)CN interactions

1993

Abstract Binding and isomerization energies of the CuCN, CuNC, CuCN+, and CuNC+ systems were investigated by means of a multireference CI perturbatively selected, MRCI-PS approach. The inclusion of the main dynamical correlation effects are evaluated. The binding energies for CuCN and CuNC are 4.37 and 4.03 eV, respectively, and those for CuCN+ and CuNC+ are 0.08 and 1.61 eV. Calculated isomerization energies are 7.86 and 35.98 kcal/mol for CuCN and Cu(I)CN isomerizations, respectively.

Enthalpies of Mixing of Some Primary Hydrogenated and Fluorinated Alcohols and Sodium Dodecanoate Aqueous Solutions

1993

Abstract The enthalpies of transfer from water to the surfactant solutions ΔH(W → W + S) of some hydrogenated and fiuorinated alkanols and of sodium dodecanoate NaL were determined. In the premicellar region the measurements were carried out as functions of both the additive and the surfactant concentrations in order to evaluate the interaction parameters between the additive and the surfactant molecules. It is shown that in this region, pair, triplet, and quadruplet interaction parameters between unlike solute molecules contribute to ΔH(W → W + S). Within the large uncertainty with which these parameters are determined because of the very narrow surfactant and alcohol concentration interva…

Induction of an Anti-Vaccine Response by T Cell Vaccination in Non-human Primates and Humans

1993

Abstract Experimental and spontaneous autoimmune disease in animals can effectively be prevented and treated by application of pathogenic autoreactive T cells in an attenuated form. This approach has become known as T cell vaccination, T cell vaccination exploits specifically the ability of the immune system to regulate its autoreactive T cells by mechanisms of network control. The success of T cell vaccination in a variety of rodent animal models has raised hopes for its use as an effective and specific therapy in human autoimmune disease. The aim of this study was to induce an anti-T cell response by T cell vaccination in humans and primates as a pre-clinical study into the feasibility an…

Bone mineral density in relation to anthropometric properties, physical activity and smoking in 75-year-old men and women

1993

Bone mineral content (BMC, gem−2) and density (BMD, gem−3) were studied in 75-year-old men and women in relation to anthropometric and certain life-style factors. This study covered all the men and women born in 1914 who were residents in the city of Jyvaskyla in 1989 (N=388). A hundred and three men and 188 women participated in bone measurements performed at the calcaneus using a 125I-photon absorption method. BMC was on average 36% and BMD 17% higher in the men than in the women. BMC and BMD associated with body mass in both sexes, and with body fat and use of estrogen in the women. There was a negative correlation between the BMD values and the number of cigarettes smoked over the entir…

Acute hormonal responses to two different fatiguing heavy-resistance protocols in male athletes.

1993

To examine endogenous hormonal responses to heavy-resistance exercise, ten male strength athletes performed two fatiguing but different types of sessions on separate days. In session A the loads for the leg extensor muscles in the squat-lift exercise were maximal so that the subjects performed 20 sets at 1 repetition maximum (RM) (20 x 1 RM x 100%), whereas during session B the loads were submaximal (70%) but the subjects performed each of the 10 sets until the RM (i.e., 10 repetitions/set or 10 x 10 x 70%). The recovery time between the sets was always 3 min. A decrease of 10.3 +/- 4.7% (P < 0.001) occurred in the squat-lift in 1 RM during session A, whereas session B led to a decrease…

Leptonic Flavor-changing Z0 Decays in SU(2)xU(1) Theories with Right- handed Neutrinos

1993

We analyze possible lepton-flavor-violating decays of the $Z^0$ particle in a minimal extension of the Standard Model, in which one right-handed neutral field for each family has been introduced. Such rare leptonic decays are induced by Majorana neutrinos at the first electroweak loop level and are generally not suppressed by the ordinary "see-saw" mechanism. In particular, we find that experimental bounds on branching ratios of the order of $10^{-5}-10^{-6}$ attainable at $LEP$ may impose constraints on lepton-flavor-mixing parameters and the masses of the heavy Majorana neutrinos.

Dominant Three-Body Decays of a Heavy Higgs and Top Quark

1993

We calculate the dominant three body Higgs decays, $H \to W^+W^-(Z^0, \gamma)$ and $H \to t\overline{t}(Z^0,\gamma ,g)$, in the Standard Model. We find that the branching ratios of these decays are of the order of few percent for large Higgs masses. We comment on the behaviour of the partial decay width $\Gamma (H \to t\overline{b}W^-)$ below the $t\overline{t}$ threshold. Numerical results of the following three body top decays, $t \to W^+b(\gamma ,g,Z^0)$ and $t \to W^+bH$, are also given. We discuss the feasibility of observing these Higgs and top decays at future high energy colliders.

CP-violation with bosons

1993

We formulate the conditions under which a purely bosonic theory (without fermions) containing neutral spin-0 particles and vector (gauge) bosons violates the CP-symmetry through the presence of CP-even and CP-odd operators in the Lagrangian. This is done without reference to explicitly CP-violating scalar sector of extended standard models (SM) with two or more Higgs doublets. The Lagrangian expressed in the mass basis of the spin-0 fields can, however, in certain cirumstances be identified with a part of the CP-violating SM with two Higgs doublets. It is instructive to consider the manifestation of CP-violation in the mass basis since this leads directly to suggestions of genuine CP-signal…

Transient photoconductivity in a discotic liquid crystal

1993

Using a time-of-flight technique, different transport mechanisms, deep trapping, multiple shallow trapping, and ideal itrinsic transport, can be observed in the different temperature and phase regions of the liquid-crystalline photoconductor hexapentyloxytriphenylene. The temperature and field dependences of carrier mobilities up to 1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$ ${\mathrm{cm}}^{2}$/V s have been determined; this value exceeds considerably the mobilities of the most commonly used organic photoconductors. The experiments reflect a variety of transport phenomena which are novel in the field of liquid-crystalline systems.

Absolute Configurations of Three Naturally Occurring Acetylenic Spiroacetal Enol Ethers

1993

The absolute configurations of three 6,7-oxygenated acetylenic spiroacetal enol ethers were determined by using the kinetic method of Horeau. The results were confirmed by the circular dichroism of the compounds in correlation with the corresponding 6,7-epoxide.

De novo expression of intercellular adhesion molecule 1 (ICAM-1, CD54) in pancreas cancer.

1993

We examined the expression of intercellular--adhesion molecule-I (ICAM-I, CD54) in 6 surgically removed pancreatic tumors and 8 pancreatic tumor cell lines. Immunohistochemistry revealed a varying percentage of ICAM-I-positive pancreas tumor cells, while normal pancreatic tissue (except for slight reactivity of endothelial cells) was not stained. The presence of the ICAM-I molecule on the cell surface and the expression of ICAM-I mRNA were investigated for 8 different pancreatic tumor cell lines. Three of these (Capan-I, Capan-2, QGP-I) expressed ICAM-I constitutively. In 4 of the ICAM-I-negative pancreas cancer cell lines, it was possible to induce a remarkable expression of ICAM-I by incu…

Hybridization ofsd- andfp-shell proton orbitals in the systemS36+37Cl

1993

Experimental and theoretical evidence is presented that the proton exchange is strongly enhanced by a mixing of single-particle configurations in $^{37}\mathrm{Cl}$ (in the system $^{36}\mathrm{S}$${+}^{37}$Cl, which is shown to be the clearest example of hybridization in nuclear physics. The experimental data on elastic and inelastic transfer are only reproduced if the complete set of single-particle states (${\mathit{d}}_{3/2}$,${\mathit{s}}_{1/2}$,${\mathit{f}}_{7/2}$,${\mathit{p}}_{3/2}$,${\mathit{f}}_{5/2}$, and ${\mathit{p}}_{1/2}$) is included in a coupled-reaction-channel calculation. The strong enhancement is explained by the hybridization of orbits of different parity. In a two-ce…

EXAFS and XANES Studies of CoxMg1−xO Solid Solutions Using a Laboratory EXAFS Spectrometer

1993

Studies of the local electronic structure and the short-range order in solid solutions CoxMg1−xO with x varying from 0.02 to 1.00 are carried out on the CoK-edge X-ray absorption spectra using a laboratory EXAFS spectrometer. A non-monotonous change of the CoO distance in the first coordination shell with a bent at about x = 0.5 is established. The second coordination shell of cobalt is formed by cobalt and magnesium atoms with a distribution close to a statistical one. [Russian Text Ignored.]

Heat shock proteins in three relatedDrosophila species belonging to theobscura group

1993

The effect of heat shock on protein synthesis in three related Drosophila species belonging to the obscura group was analyzed on SDS-acrylamide gels. Four major heat shock proteins (hsps) were found in these species, in which synthesis reaches a maximum at 34 degrees C. Although the higher molecular weight proteins are conserved, differences in size were found for the small hsps in these species. By means of in situ hybridization using D. melanogaster probes for the small hsp genes, it was inferred that the small hsp genes of the obscura group species are clustered at the 27A locus in all three species.

WAVELET ANALYSIS OF THE MULTIFRACTAL CHARACTER OF THE GALAXY DISTRIBUTION

1993

We have determined generalized dimensions of the observed distribution of galaxies. Their different values indicate that this distribution may be described as a multifractal. In order to analyse this distribution further, we have applied local wavelet transforms. Wavelets provide us with an interesting tool to analyse the large-scale structure which can be mathematically quantified and intuitively visualized. Comparing the results of these transforms at different dilation factors helps to visualize more clearly the nearly singular nature of the distribution. This method also allows us to determine the range of the local density power laws

Osteogenesis imperfecta and hyperplastic callus formation: light- and electron-microscopic findings.

1993

In rare cases of osteogenesis imperfecta, an "overshoot" growth of new bone may occur, which, clinically gives the impression of a tumour. This condition is known as hyperplastic callus formation. Morphology showed an excessive mixed desmal-chondral osteoneogenesis. Atypical collagen fibrils in non-callus tissue represent an indicator for this callus formation in individual patients.

Immuno-detection of a major integral protein in the vacuole membrane of vegetative plant cells

1993

Morphological abnormalities induced by Fenoxycarb on the ectoparasitic larval stage ofPhanerotoma (Phanerotoma) ocularisKohl (Hym., Braconidae)

1993

The Juvenile Hormone Analog Fenoxycarb at concentrations of 0.001 μg/ml, 0.005 μ/ml, 0.01 μg/ml, 0.05 μg/ml and 0.1 μg/ml had an adverse effect on the ectoparasitic larva of Phanerotoma (Phanerotoma) ocularis when topically applied. The total percentage of abnormalities obtained was higher (63.3 %-93.3 %) if the treatment was applied on the third substage than when it was applied on the fourth substage (53.3 %-76.7%). The activity rate was concentration dependent for both substages. Zusammenfassung Durch Fenoxycarb-Behandlung hervorgerufene Abnormitaten bei Larven des Ektoparasiten Phanerotoma (Phanerotoma) ocularis Kohl (Hym., Braconidae) Topikalbehandlung der Larven von Phanerotoma (Phane…

Parasitization ofEphestia kuehniellaZeller (Lep., Pyralidae) byPhanerotoma (Phanerotoma) ocularisKohl (Hym., Braconidae)

1993

Laboratory studies of the parasitism by P. (P.) ocularis into E. kuehniella showed that this parasitoid had a great capacity to parasitize the host. Real parasitism rate turned between 84.5% and 100% whereas effective parasitism and adult emergence rate were, comparatively, lower. Superparasitism rate was low (16.57 %). Zusammenfassung Parasitierung von Ephestia kuehniella Zeller (Lep., Pyralidae) durch Phanerotoma (Phanerotoma) ocularis Kohl (Hym., Braconidae). Parasitismus, Superparasitismus und Schlupfraten Laboruntersuchungen zur Parasitierung von Ephestia kuehniella durch P. (P.) ocularis zeigten, das dieser Parasitoid eine sehr hohe Parasitierungsleistung hat. Die reale Rate lag zwisc…

Morphological abnormalities induced by Fenoxycarb on the pupa ofPhanerotoma (Phanerotoma) ocularisKohl (Hym., Braconidae)

1993

Fenoxycarb at concentrations of 0.001 μg/ml, 0.005 μg/ml, 0.01 μg/ml, 0.05μg/ml and 0.1 μg/ml had an adverse effect on the pupa of Phanerotoma (Phanerotoma) ocularis. When topically applied, it induced morphological abnormalities. The percentage of anomalous obtained depended of developmental pupal stage and was higher when was applied in the first moment of development (80 %-90 %) than in the final of development (50%-60%). These anomalous was inviables. Zusammenfassung Morphologische Abnormitaten bei Puppen von Phanerotoma (Phanerotoma) ocularis Kohl (Hym., Braconidae) nach Einwirkung von Fenoxycarb Fenoxycarb, in Konzentrationen von 0.001 μg/ml, 0.0005 μg/ml, 0.01 μg/ml, 0.05 |μg/ml und …

Domain Structures in Langmuir-Blodgett Films Investigated by Atomic Force Microscopy

1993

Investigations of phase-separated Langmuir-Blodgett films by atomic force microscopy reveal that on a scale of 30 to 200 micrometers, these images resemble those observed by fluorescence microscopy. Fine structures (less than 1 micrometer) within the stearic acid domains were observed, which cannot be seen by conventional optical microscopic techniques. By applying the force modulation technique, it was found that the elastic properties of the domains in the liquid condensed phase and grains observed within the liquid expanded phase were comparable. Small soft residues in the domains could also be detected. The influence of trace amounts of a fluorescence dye on the micromorphology of monol…

Measurement of inclusive production of light meson resonances in hadronic decays of the Z0

1993

A study of inclusive production of the meson resonances ρ0, K*0 (892), f{hook}0 (975) and f{hook}2 (1270) in hadronic decays of the Z0 is presented. The measured mean meson multiplicity per hadronic event is 0.83 ± 0.14 for the ρ0 0.64 ± 0.24 for the K*0 (892), 0.10 ± 0.04 for the f{hook}0 (975) in the momentum range p > 0.05pbeam (xp > 0.05) and 0.11 ± 0.05 for the f{hook}2 (1270) for xp > 0.1. These values and the corresponding differential cross sections ( 1 σhadr) dσ dxp for the vector mesons are in good agreement with the predictions of the JETSET 7.3 PS and HERWIG 5.4 models. The f{hook}2 (1270) production is overestimated by HERWIG but its xp-shape is correctly reproduced. T…

Somatic embryogenesis and plant regeneration in a woody species: the European Spindle Tree (Euonymus europaeus L.).

1993

Somatic embryogenesis and subsequent plant regeneration of Euonymus europaeus L (European Spindle Tree) were obtained from square pieces of mature zygotic embryos with an intervening callus phase. Callus and somatic embryos were induced using a Murashige and Skoog's semi-solid basal medium supplemented with several combinations of auxins and cytokinins. The greatest number of somatic embryos was obtained with a continuous exposure to 22.8 μM indoleacetic acid and 0.046 μM kinetin. The frequency of somatic embryogenesis from zygotic embryos depends on the cold conservation time of seeds. The embryos frequently germinated on the same medium. Further development of somatic embryos into plantle…

Region specific expression of furin mRNA in the rat brain.

1993

The distribution of furin mRNA was examined in the rat central nervous system. Northern blot analysis reveals the presence of a 4.4 kb band in all brain tissues examined. In situ hybridization analysis of frozen rat brain sections using a radioactively labeled antisense cRNA probe to rat furin demonstrated moderate to low levels of expression in both neuronal and non-neuronal tissue in all areas examined. Interestingly, higher levels of furin were expressed in selective regions which include the ventricles (the choroid plexus and ependymal cells), the islands of Calleja, the hippocampus and the pineal gland. the ubiquitous localization of furin in the brain is consistent with its postulated…

La estructura interna de las tormentas mediterráneas

1993

La instalación de un SAIH (Sistema Automático de Información Hidrológica) en la fachada oriental española permite estudiar la estructura interna de las tormentas mediterráneas. Los sistemas tradicionales efectúan un registro cada 24 horas, hecho que enmascara las características de la precipitación. El SAIH toma datos cada 5 minutos y supone una eficaz herramienta para el estudio de la variabilidad espacio-temporal de la lluvia. Con los datos proporcionados por esta red, se han analizado detalladamente tres episodios típicos mediterráneos, a partir de series de mapas de intensidad de precipitación elaborados cada 5 minutos. El estudio corrobora una disposición horizontal jerárquica, donde s…