2,2′-Bipyrimidin(oxalato)kupfer(II)-Komplexe: vom einkernigen Komplex zum zweidimensionalen Schichtpolymer

1993

Supersymmetry in the standard model of electroweak interactions

1993

Abstract Starting from the peculiar chirality pattern of weak and electromagnetic interactions, established by experiment, we show that the minimal standard model contains supersymmetry, though in a new, unconventional, realization. It appears as an action on the fields but is not an invariance of the lagrangian. This supersymmetry which is not in conflict with experiment, is seen to be the raison d'etre of the Higgs fields and provides a geometrical understanding of spontaneous symmetry breaking. It turns out that this approach which is based on the fundamental role of left- and right-chiral spinor fields in weak interactions, has many similarities to models developed in the framework of n…

Cell Cycle in Potentially Dedifferentiating Cereal Mesophyll Protoplasts Cultured in vitro II. Behaviour of the Cytoskeleton

1993

Summary Following up on the recent finding that mesophyll protoplasts of wheat and oats were able to reenter the cell cycle when cultured in vitro , the behaviour of the cytoskeleton was studied. The aim was to elucidate whether changes in the cytoskeletal patterns correlate with the abnormal progression through the cycle observed previously. Protoplasts freshly isolated from mature mesophyll tissue (type B) exhibited very few, fragmented microtubules, whereas mesophyll protoplasts isolated from immature leaf tissue (type A) showed an abundant network fo microtubules. Type B protoplasts of wheat, which were able to reenter but recalcitrant to complete S-phase, failed to reestablish a microt…

Nonlinear optical spectra of conjugated polymers: Effect of long-range coulomb interactions

1993

Abstract Nonlinear optical spectra of conjugated polymers are theoretically studied in the Su-Schrieffer-Heeger model supplemented by long-range Coulomb interactions. Excitonic correlation for electron-hole excitations in explicitly taken into account by a standard method. Nonlinear susceptibilities χ (3) are calculated numerically with a standard sum-over-states method for finite chains (up to 1000 sites). Using moderate interaction strength, our calculations can reproduce many distinct features observed in the linear and nonlinear spectra (two-photon absorption, third-harmonic generation, and electroabsorption) of polydiacetylenes and some other polymers. Especially, a hump in the spectru…

Sulfotransferase-mediated mutagenicity of 1-hydroxymethylpyrene and 4H-cyclopenta[def]chrysen-4-ol and its enhancement by chloride anions.

1993

1-Hydroxymethylpyrene (HMP), a primary benzylic alcohol, and 4H-cyclopenta[def]chrysen-4-ol (OH-CPC), a secondary benzylic alcohol, were investigated for mutagenicity in Salmonella typhimurium (reversion of the his- strain TA98) in the presence of various xenobiotic-metabolizing systems. In the direct test, HMP was inactive and OH-CPC was very weakly active. In the presence of NADPH-fortified postmitochondrial fraction from rat liver (S9/NADPH), no activation of OH-CPC was observed, whereas strong mutagenic effects were elicited by HMP. In the presence of cytosol and 3'-phosphoadenosine-5'-phosphosulfate (PAPS), both alcohols were activated to potent mutagens. For equal mutagenic effects, a…

A theoretical study of the collinear reaction F+H2→HF+H using multiconfigurational second-order perturbation theory (CASPT2)

1993

Abstract The second-order perturbation method (CASPT2) with a single state multiconfigurational reference function generated in complete active self-consistent field (CASSCF) calculations has been used to compute the collinear barrier height, saddle point geometry, and exothermicity of the reaction F+H 2 →HF+H. Comparison with full configuration (FCI) calculations with small basis sets shows that the CASPT2 method is capable of reproducing accurately the exact benchmark results correlating seven electrons. Large atomic natural orbital basis sets are used at the seven- and nine-electron level of correlation. With the largest ANO basis set used, F[7s6p5d4f2g]/H[6s5p4d2f], the computed nine-el…

First tetrathiafulvalene (TTF) cation-radical salt containing the inorganic polyoxometalate β-[Mo8O26]4⊖

1993

Vascular modifications within a choroidal osteoma

1993

We report a case of choroidal osteoma followed-up for 7 years. During this lapse of time the choroidal osteoma showed slight enlargement, development of subretinal hemorrhage and modifications of intratumoral vascularization. Some large intratumoral vessels visible at first examination disappeared at follow-up, while other vessels not observed before developed. The changes in the vascularization of the choroidal osteoma denote profound dynamics in the processes of osseous rearrangement of the tumor.

Characterization of sensory neurotransmission and its inhibition via alpha 2B-adrenoceptors and via non-alpha 2-receptors in rabbit iris.

1993

To find out whether, and which type of, adrenoceptors mediate prejunctional inhibition of sensory neurotransmitter release from trigeminal fibres, the modulation of twitch response to electrical field stimulation on rabbit isolated iris was investigated. Evoked iris sphincter contractions consisted of a minor fast cholinergic and a large slow component. The latter was unaffected by atropine and guanethidine, hence nonadrenergic noncholinergic in nature (NANC), but nearly completely abolished by capsaicin pretreatment and by the neurokinin receptor antagonist spantide. The response was probably not mediated by NK2 receptors as SR 48,968, an NK2 selective nonpeptide antagonist, failed to redu…

Dissociation energies within selected configuration interaction and perturbation theory

1993

Abstract Selected configuration interaction (CI) calculations and second-order perturbational theory are used to truncate systematically multireference single and double excitation CI (MRCI) expansions in the calculation of the bond dissociation energies of several systems like the single-bonded LiF molecule or the multiple-bonded N2, NO and O2 diatomic systems. The method is extended to compute the CH bond dissociation energy ofethene C2H4. It is shown how the proposed scheme (perturbation-selected MRCI (MRCI-PS)) is able to reproduce the accuracy of complete MRCI expansions with only a small number of configurations variationally evaluated.

The distinction of bipolar II disorder from bipolar I and recurrent unipolar depression: results of a controlled family study.

1993

The aim of the study was to differentiate bipolar II, bipolar I and recurrent unipolar depression by their familial load for affective disorders. Eighty bipolar, 108 unipolar, 80 control subjects and interviewed first-degree relatives were diagnosed according to Research Diagnostic Criteria using the Schedule for Affective Disorders and Schizophrenia – lifetime version. The morbid risks for bipolar I disorder were equivalent in relatives of bipolar I (3.6%) and bipolar II (3.5%) subjects and lower in relatives of unipolar subjects (1.0%). The morbid risks of relatives for bipolar II disorder distinguished bipolar II subjects (6.1%) from bipolar I subjects (1.8%), from unipolar depressives (…

Antiproliferative and chemomodulatory effects of interferon-γ on doxorubicin-sensitive and -resistant tumor cell lines

1993

Biological agents might offer various therapeutic opportunities in the treatment of cancer, including a direct and/or host-mediated antiproliferative effect and also the possibility to favorably modulate tumor resistance to antineoplastic drugs. We studied the in vitro antiproliferative effects of interferon (IFN)-gamma on the mouse B16 melanoma and Friend erythroleukemia, and the human K562 erythroleukemia, as doxorubicin (DXR)-sensitive and -resistant (multidrug resistant) variants. These effects were marked in B16 melanoma and rather slight in K562 erythroleukemia, without any difference between the DXR-sensitive and -resistant lines. The chemosensitive variant of Friend erythroleukemia …

Physics at new accelerators: Looking beyond the Standard Model

1993

Abstract Neutrino masses can have important implications in nuclear and particle physics, astrophysics and cosmology. Apart from the effects related to solar neutrinos, neutrino oscillations, dark matter, beta and double beta decays, massive neutrinos can also produce signals in the new accelerators. Here I focus on μ and τ number violating processes, very promising for muon and tau factories, as well as on the signatures associated with spontaneously broken R parity supersymmetry and neutral heavy leptons. These include the possibility of high rates for single chargino and neutralino production at LEP, LHC/SSC, as well as new signatures involving invisibly decaying Higgs bosons.

Intestinal helminth communities of the long-finned pilot whale (Globicephala melas) off the Faroe Islands.

1993

SUMMARYThe intestines of 170 long-finned pilot whales, Globicephala melas, caught off the Faroe Islands (N.E. Atlantic) were examined for helminth parasites. Eight species were detected but only 4 occurred in at least 10% of the sample. No core or recurrent group of species were identified and no correlations between abundances of species were significant. Diversity values were far below those reported for other endotherms. Colonization by helminths was random, whales not being readily colonized. These features point to largely unpredictable, isolationist infracommunities, there being little potential for inter-specific interactions. Older hosts tended to harbour more diverse infracommuniti…

Surgery for fracture of the calcaneus. 5 (2-8) year follow-up of 20 cases.

1993

20 displaced intraarticular fractures of the calcaneus were treated by open reduction and internal fixation. Results were evaluated according to a standardized protocol. With an average follow-up of 5 (2-8) years, results were excellent or good in 15 cases and fair or poor in 5 cases. An accurate radiographic study and CT scanning are essential for understanding these fractures. We feel that restoring calcaneal shape as anatomic as possible, getting an appropriate reduction of the posterior joint surface by a surgical procedure with early mobilization, and delayed weight bearing would be a good option in treatment of these fractures.

Crystallization kinetics in relation to polymer processing

1993

Phase distribution of quenched samples has been determined by a deconvolution procedure of WAXS spectra in a wide range of cooling rates. The informations collected together with isothermal and DSC results provide a very wide set of data on the crystallization kinetics of polymers relevant which covers conditions encountered in most polymer processing operations. They have been compared with predictions of a non-isothermal crystallization model assuming two independent and parallel crystallization processes competing during solidification.

Reply to comment on “A MRCI PS and CASSCF study of the ground state MgO dissociation energy”

1993

To compute the dissociation energy of MgO, the relationship among the size of the active space in CASSCF wavefunctions, the computed De and the continuity of ∂E/∂r is studied. Basis set influence is also considered. Finally, it is concluded that the dissociation energy of MgO referred to ground state atoms is 2.32±0.1 eV.

Ultrastructural Pathology of Eccrine Sweat Gland Epithelial Cells in Globoid Cell Leukodystrophy

1993

Three of four children were recognized by deficient β-galactocerebrosidase activities as having globoid cell leukodystrophy inclusions in sweat gland epithelial cells, similar in ultrastructure to those seen in Schwann cells. This observation in globoid cell leukodystrophy emphasizes the need to include sweat gland epithelial cells in examinations of skin in globoid cell leukodystrophy, as well as in any neurometabolic disorder. ( J Child Neurol 1993;8:171-174).

Friedelane triterpenes from the stem bark of Caloncoba glauca

1993

Further investigation of the stem bark of Caloncoba glauca has yielded three minor (D:A)-friedo-oleanane derivatives. These have been identified, on the basis of NMR studies, as the known compound kokoonol [3-oxo-(D:A)-friedo-olean-27-ol] and the novel natural products kokoonal [3-oxo-(D:A)-friedo-olean-27- al] and 3β,21β-dihydroxy-30-nor-(D:A)-friedo-olean-27-oic acid.

Vitamin A Inhibits Doxorubicin-Induced Membrane Lipid Peroxidation in Rat Tissues in Vivo

1993

The antioxidant activity of vitamin A against lipid peroxidation induced by doxorubicin in rat tissues in vivo was investigated. A single ip injection of doxorubicin (30 mg/kg body wt) markedly raised the level of peroxidated lipids measured as TBARS and conjugated dienes in heart and brain membrane preparations. Other tissues, such as retina and liver, did not show any increase of lipid peroxides over control values. Pretreatment of rats with two daily subcutaneous injections of retinol palmitate (0.25 g/kg body wt), for 2 days, before injecting doxorubicin, inhibited peroxidation of heart and brain membrane lipids. The antioxidant action of vitamin A does not appear to be mediated by enha…

Oxygen-haemoglobin dissociation curve in hypoxic rats of first or second generation.

1993

SUMMARY 1. Albino Wistar rats were raised in a normobaric hypoxic environment (10% O2 in N2). Two generations of hypoxic rats were observed for changes in their haemoglobin-oxygen (Hb-O2) dissociation curves (ODC), 2,3-diphosphoglycerate (2,3-DPG), haemoglobin (Hb), and Hill coefficients at P50 (n50). The first generation were called (H1) and the second generation (H2). The control group (N) had a normoxic environment. 2. Thirty-five rats (13 N rats, 12 H1 rats and 10 H2 rats) were used. The 2,3-DPG was significantly higher in both hypoxic groups when compared with N rats (2.02 ± 0.51 mmol/L) but 2,3-DPG of H2 rats was significantly lower than that of H1 rats (H1 = 3.48±0.58 mmol/L and H2 =…

The kinetics of defect accumulation under irradiation: many-particle effects

1993

The kinetics of Frenkel defect accumulation under permanent particle source (irradiation) is discussed with special emphasis on many-particle effects. Defect accumulation is restricted by their diffusion and annihilation, A + B → 0, if the relative distance is less than the critical distance r0. A novel formalism of many-point particle densities based on Kirkwood's superposition approximation is developed to take into account aggregation of similar defects (A−A, B−B). The dependence of the saturation concentration after a prolonged irradiation upon spatial dimension ( = 1, 2, 3), defect mobility and the initial correlation within geminate pairs is analyzed. It is shown that the defect conce…

Cytogenetic effects of promutagens in genetically engineered V79 Chinese hamster cells expressing cytochromes P450.

1993

Abstract V79 Chinese hamster cell lines genetically engineered to express rat CYP2B1, CYP1A1, CYP1A2, and their parental cell lines V79-MZ, without acetyltransferase, and V79-NH, with acetyltransferase, were studied for chromosome aberrations and sister chromatid exchange induced by aflatoxin B 1 , cyclophosphamide, benzo[a]pyrene, 7,12-dimethylbenz[a]anthracene and dimethylnitrosamine. The parental V79 cell lines did not show clastogenic effects. Significant clastogenic effects were observed after an 18 h exposure to aflatoxin B 1 and cyclophosphamide in CYP2B1 expressing cells, to benzo[a]pyrene in CYP1A1 and CYP1A2 expressing cells, to 7,12-dimethylbenz[a]anthracene and dimethylnitrosami…

Theoretical search for low-band-gap vinylene linked polymers: heteroarylene vinylene copolymers

1993

Abstract We report a study of the role of the heteroatoms on the electronic properties of poly(thienylene vinylene-co-furylene vinylene), poly(thienylene vinylene-co-pyrrylene vinylene) and poly(furylene vinylene-co-pyrrylene vinylene) at the VEH level. The theoretical calculations show that the electronic properties depend on the nature of the heteroatoms present in the copolymer. The VEH trends are in accord with experimental and theoretical data reported in the literature.

L'accès à la formation professionnelle dans trois secteurs de l'économie européenne

1993

CEDEFOP; série panorama, analyse comparéeRéférence interne : 93035

Farbduplexsonographische Messung der Lymphknotenperfusion: Ein Beitrag zur Diagnostik der zervikalen Metastasierung*

1993

The objective of this study was to find additional sonomorphological criteria for determining the status of enlarged lymph nodes. By using colour-coded duplex sonography the perfusion of 63 lymph nodes in the neck was analysed. The status was confirmed either histologically or clinically (29 metastases from squamous cell carcinomas and 34 acute or chronic inflammatory nodal diseases). A quantitative evaluation of the pulsatility measured in 51 lymph nodes by computing the Pourcelot-Ratio and the Mean Pulsatility Index yielded significant differences between the two groups. By definition of a limiting value of the Pourcelot-Ratio (0.75) for the prediction of benignity, the specificity and th…

Prediction of maxima and minima in the curve of total sorption parameter in ternary polymer systems. Influence of ternary interaction parameter

1993

Flory-Huggins theory modified by Pouchly has been applied to predict maxima and minima in the curve of total sorption in ternary polymer systems formed by a polymer and two liquids. In this work, different diagrams based on experimental magnitudes easily obtained such as the difference in affinities of liquids, solvents and non solvents, and the solvent molar volume ratio. Total sorption parameter has been considered to be the decisive magnitude to define extrema conditions in both cosolvent and cononsolvent ternary polymer systems. The theoretical prediction is not altered by the inclusion of ternary interactions. Different examples of ternary systems dealing with vinyl polymers and polydi…

Apparent activation energies and apparent frequency factor in polarographic waves of paludrine-Zn(II)

1993

Abstract Arrhenius and Vlcek plots of ac 1 and dp polarograms of paludrine-Zn complexes are tested in order to understand the apparent activation energies and pre-exponential factor, and their dependence on the potential. These empirical treatments are useful for obtaining information about the energetic contributions of the elemental processes associated with the Zn(II) and paludrine ligands in the overall mechanism of reduction of the complex 2:1 on the mercury interface.

From where do quantum groups come?

1993

The phase space realizations of quantum groups are discussed using *-products. We show that on phase space, quantum groups appear necessarily as two-parameter deformation structures, one parameter (v) being concerned with the quantization in phase space, the other (η) expressing the quantum groups as “deformation” of their Lie counterparts. Introducing a strong invariance condition, we show the uniqueness of the η-deformation. This suggests that the strong invariance condition is a possible origin of the quantum groups.

Weight Gain Induced by Long-Term Propranolol Treatment

1993

Theoretical characterization of the electronic properties of unsymmetrical phthalocyanine analogues

1993

Abstract The electronic structure of unsymmetrical phthalocyanine-based compounds is investigated using the nonempirical valence effective Hamiltonian (VEH) method. The VEH results predict a slight but continuous destabilization of the HOMO level and a monotonous narrowing of the HOMO-LUMO energy gap as the size of the system increases. The theoretical trends are found to agree with optical absorption experimental data and show that the optical properties of phthalocyanine can be monitored by adjusting the size of the π-conjugated macrocycle.

Search for particles with unexpected mass and charge in Z decays

1993

During 1989 and 1990 over 180 000 hadronic and leptonic events, corresponding to 8 pb-1 of luminosity, were collected by the ALEPH detector in a scan of the Z peak at the e+e- collider LEP. This letter reports the results of a search in these data for particles with unexpected mass and charge by measurement of the ionization energy loss of charged tracks in the ALEPH TPC central tracking detector. The mass limits for the pair production of fractionally charged particles and of heavy, long lived charged particles are extended to 43 GeV/c2 at 90% confidence level. If single production of a heavy particle is considered, the mass limit is extended to more than 70 GeV/c2. RI Perrier, Frederic/A-…

Exercise echocardiography for the evaluation of patients after nonsurgical coronary artery revascularization.

1993

Objectives. The purpose of this study was to demonstrate the accuracy of stress echocardiography for detecting the progression of coronary artery disease after nonsurgical revascularization. Background. The expanding role of nonsurgical coronary revascularization procedures mandates the development of sensitive noninvasive techniques for tbe detection of recurrent ischemia. Methods. Bicycle stress echocardiography was performed in a series of 86 patients 6.5 ±1.3 months after a revascularization procedure. Seven patients were excluded from analysis because of poor echocardiographic image quality. Results. Digital analysis achieved a sensitivity of 83% for the entire group and a specificity …

Cycloadditions of vinylindoles with chiral carbodienophiles: the first asymmetric Diels-Alder reactions in the vinylhetarane series

1993

Abstract The first asymmetric Diels-Alder reactions of some 3- and 2-vinylindoles with (N-propenoyl)bornane-10,2-sultam are described. With one exception, the experimental results are indicative of a high π-facial diastereoselectivity. Following a related procedure, 3-vinylindoles were also allowed to react with a racemic bis(naphthylsulfonyl)-dienophile to furnish tetrahydrocarbazoles with endo-diastereoselectivity.

Molecular diversity at the self-incompatibility locus is a salient feature in natural populations of wild tomato (Lycopersicon peruvianum)

1993

A cDNA encoding a stylar protein was cloned from flowers of self-incompatible wild tomato (Lycopersicon peruvianum). The corresponding gene was mapped to the S locus, which is responsible for self-incompatibility. The nucleotide sequence was determined for this allele, and compared to other S-related sequences in the Solanaceae. The S allele was used to probe DNA from 92 plants comprising 10 natural populations of Lycopersicon peruvianum. Hybridization was conducted under moderate and permissive stringencies in order to detect homologous sequences. Few alleles were detected, even under permissive conditions, underscoring the great sequence diversity at this locus. Those alleles that were de…

Structural dissection of the multidomain kininogens. Fine mapping of the target epitopes of antibodies interfering with their functional properties.

1993

Kininogens, the large precursor molecules of the vasoactive kinin peptides, are prototypic multidomain proteins serving numerous functions. To investigate their structure-function relationships, we have raised a panel of monoclonal antibodies against human H-kininogen and L-kininogen and fragments thereof and characterized them with respect to their target epitopes. Of 35 antibodies, 12 were directed to the amino-terminal domains (D1 to D3) of cystatin-like structure, 3 recognized domain D4 bearing the kinin segment, 17 bound to the carboxyl-terminal domains of H-kininogen (D5H and D6H), and 3 bound to the carboxyl-terminal domain D5L of L-kininogen. At least 14 distinct epitopes spread ove…