showing 36 of ~574560 from 574555 documents
Volatile flavour components of ocimum basilicum var. hispidum (lam.) Chiov.
1991
The volatile components obtained by steam-distillation ofOcimum basilicum var. hispidum (Lam.) Chiov. (Labiatae) were analysed by gas chromatography (GC) and gas chromatography—mass spectrometry (GC-MS). A total of 21 compounds, representing ca 90% of the total oil, were identified. The identity of the main component (82%), dihydrotagetone, was confirmed by 1H- and 13C-NMR spectroscopy. This is the first report of this compound in the genus Ocimum.
A comparison of spreading and motility behaviour of 8701-BC breast carcinoma cells on type I, I-trimer and type V collagen substrata. Evidence for a …
1991
Ductal infiltrating carcinoma (d.i.c.) of human breast is a highly invasive neoplasm characterized by enhanced deposition of collagen. Paradoxically, enhanced collagen deposition is not correlated with inhibition of the migration of tumour cells into the host tissue. d.i.c. is characterized by the reappearance of ‘embryonic’ type I-trimer collagen and an increase in type V collagen content in the matrix. The effects of these two collagen types were compared with type I collagen as culture substrata on the spreading pattern, cytoskeletal organization and motile behaviour of 8701-BC breast carcinoma cells using rhodamine-phalloidin staining, a DNAase I-competition assay, scanning electron mic…
Ranges of interaction in $$p\bar p$$ scattering at low energies
1991
Thep¯ p cross sections at low energies are analysed in the framework of the optical model. It is shown that the annihilation range is closely related to the size of the proton as measured in electromagnetic and hadronic interactions. At larger distances thep¯ p interaction has the similar character as the NN one.
Dienediolates of Unsaturated Carboxylic Acids in Synthesis. Tandem Michael Diechmann Synthesis of Substituted 2-Cyclohexenones
1991
Abstract 3,5-Disubstituted 2-Cyclohexenones are prepared by tandem Michael-Dieckmann addition of lithium dienediolates of dimethylacrylic and β-methylcinnamic acids to lithium carboxylates of unsaturated carboxylic acids.
A novel germacranolide-aminoacid adduct dimer from centaurea aspera
1991
Abstract The novel germacronolide-valine adduct dimer 1 has been isolated from aerial parts of Centaurea aspera var. aspera . Its structure has been determined by spectroscopic methods.
Phase II study of mitomycin C, etoposide and vindesine in metastatic stage IV non-small-cell lung cancer.
1991
A total of 72 patients with metastatic stage IV non-small-cell lung cancer (NSCLC) were treated with combination chemotherapy comprising the MEV regimen (mitomycin C, 8 mg/m2 given i. v. on day 1; etoposide, 100 mg/m2 given i.v. on days 1–3; and vindesine, 3 mg/m2 given i.v. on day 1; treatment repeated every 3 weeks). In 64 evaluable patients, the objective response rate was 37% (complete responses, 4.7%; partial responses, 32.3%). The median survival was 7.6 months for all patients. The treatment was very well tolerated. MEV proved to be an active and non-toxic regimen for the treatment of metastatic NSCLC.
Verschlußikterus: histologische Diagnostik durch perkutane endoluminale Gallengangsbiopsie
1991
32 forceps biopsies were performed in 30 patients with obstructive jaundice during percutaneous transhepatic biliary drainage procedures. In one patient an adequate specimen could not be obtained. In 25 of the remaining 31 cases diagnosis was confirmed histologically (malignant tumours: n = 22, benign stricture: n = 3). In 6 patients false-negative results were obtained. Transluminal biopsy is an easily performed adjunct to percutaneous transhepatic diagnostic interventions with minimal additional discomfort for the patient. In many cases percutaneous needle biopsy can be avoided. Forceps biopsy enables nonoperative histological diagnosis of small carcinomas of the bile ducts.
Measurements of the antiproton-proton elastic cross section in the beam momentum range between 180 and 600 MeV/c
1991
The differential cross section for antiproton-proton elastic scattering has been measured for the beam momenta between 180 and 600 MeV/c. The real-to-imaginary ratio of the forward elastic scattering amplitude is derived from the Coulomb-nuclear interference. The ratio is found to be close to zero between 180 and 500 MeV/c with a minimum ofρ=−0.14 at 260 MeV/c. This result is contrary to model predictions. The phase shifts for thes-,p- andd-waves are extracted. The partial wave compositions of the elastic and inelastic cross sections have been determined. A large contribution of thep-wave is identified in the antiproton-proton interactions at small momenta.
Dynamic Anomalies and their Relation to the Glass Transition: A Neutron Scattering Study of the Glass Forming Van der Waals Liquid Ortho-terphenyl
1991
Neutron scattering experiments on the molecular glass former ortho-terphenyl reveal a dynamic anomaly at a temperature Tc ≈ 290 K well above the calorimetric glass temperature Tg = 243 K. Close above Tc the density autocorrelation function ΦQ(t) shows a two step decay over 4–5 decades in time. The slower component obeys the time-temperature superposition principle. Its line shape can be well parametrized by a Kohlrausch law and is strongly temperature dependent as its relaxation time scales with the shear viscosity. Thus this component is identified with the structural relaxation (α-process). The faster component (β-process) is much less temperature dependent. Its line shape factorizes in a…
Relaxational dynamics at the class transition in orientational and canonical glasses investigated by dielectric spectroscopy
1991
Abstract Measurements of the dielectric permittivity are reported for the canonical glass glycerol and for solid solutions of ferroelectric betaine phosphite and ferroelectric betaine phosphate, which can be viewed as protype systems of orientational glasses. In this latter system long range dipolar order is suppressed by the competing ferroelectric and antiferroelectric interactions and the dipolar moments freeze-in devoid of long range order. In both systems the relaxation dynamics is studied for frequencies 10−2Hz≤ν≤106Hz, close to the glass transition temperature. The relaxation dynamics is characterized according to Angell's classification scheme of strong and fragile glass-formers.
BROWNIAN DYNAMICS SIMULATIONS WITHOUT GAUSSIAN RANDOM NUMBERS
1991
We point out that in a Brownian dynamics simulation it is justified to use arbitrary distribution functions of random numbers if the moments exhibit the correct limiting behavior prescribed by the Fokker-Planck equation. Our argument is supported by a simple analytical consideration and some numerical examples: We simulate the Wiener process, the Ornstein-Uhlenbeck process and the diffusion in a Φ4 potential, using both Gaussian and uniform random numbers. In these examples, the rate of convergence of the mean first exit time is found to be nearly identical for both types of random numbers.
Polyenolates of Unsaturated Carboxylic Acids in Synthesis. Synthesis of Unsaturated α-Amino Acids and β-Hydrazing Acids
1991
Abstract Regioselective reaction of lithium diene-and triene-diolates 1 and 2 with O-diphenylphosphinyl hydroxylamine affords unsaturated α-amino acids 3 and 4. Addition to DEAD leads selectively to γ-hydrazino unsaturated acids 5 and 6.
A Comment on form-factor mass singularities in flavor changing neutral currents
1991
Flavor-changing effective verticesq l q h V 0, whereV 0 represents a neutral gauge boson (γ,Z 0,g), involving a heavy external quark, are discussed within the standard model at one-loop level and second-order approximation in external momenta and masses: the logarithmic singular terms in the form factors at vanishing mass of the internal quark in the loop have to be replaced by pieces coming from next order in external momenta. Implications in theb→d+X penguin transitions are commented.
Synovial fluid-derivedYersinia-reactive T cells responding to human 65-kDa heat-shock protein and heat-stressed antigen-presenting cells
1991
Humoral and cellular immune reactions to heat-shock proteins have been implicated in the pathogenesis of arthritis. Heat-shock proteins occur in bacteria as well as all eukaryotes and have been highly conserved during evolution. Cross-reactivity between bacterial and human heat-shock proteins induced at the site of inflammation may underlie the pathogenesis of some forms of arthritis. In order to test this hypothesis, we raised and cloned a Yersinia-specific T cell line from the synovial fluid lymphocytes of a patient with Yersinia-induced reactive arthritis. From this line we obtained a CD4+ T cell clone that proliferated in response to Yersinia antigens and both to the mycobacterial and t…
Changes in selected biochemical parameters in the brain of the fish, Anguilla anguilla (L.), exposed to lindane.
1991
Crustal xenoliths from Cenozoic volcanic fields of West Germany: Implications for structure and composition of the continental crust
1991
Crustal xenoliths in three Cenozoic volcanic fields of West Germany, the Northern Hessian Depression (NHD), the Eifel and the Urach/Hegau, include medium to high-grade meta sedimentary and felsic to mafic meta-igneous rocks. Also present in all three suites are pyroxenites and hornblendites. For each volcanic field, a model crustal profile is proposed based on calculated or measured P-wave velocities of xenoliths and depth-Vp relationships (EGT Central Segment and Rhenish Massif traverses). The xenolith lithologies from the NHD and the Eifel show some similarities. The middle crust between the depths of about 10 and 25 km consists mainly of meta-sediments, felsic gneisses and granulites. Me…
Full band spectroscopic studies on the molecular mobility of diluted alcohols
1991
Abstract Static permittivity has been determinded for pure n-decanol and cyclohexanol and their solutions in cyclohexane up to very dilute solutions, the dipole moment is found to decrease with the increase in concentration to a minimum, then it increases continuously. At a certain concentration range, no effect of temperature on the measured dipole moments could be observed, within the observed temperature interval. The dielectric loss was measured in the frequency range from o.1 GHz to 670 GHz. The data are analysed in several Debye and Frohlich terms and the results are discussed.
Calculated rJ2-type effective dipole moment parameters for fundamental bands of tetrahedral XY4 molecules
1991
Abstract Formulas in terms of basic molecular constants are presented for effective dipole moment parameters which are responsible for second-order corrections to the line intensities of fundamental bands of tetrahedral XY 4 molecules. Two cases have been considered. In the first case all bands were considered as separate bands. In the second case the ν 2 and ν 4 bands were considered as interacting bands. The influence of effective Hamiltonian transformations on effective dipole moment parameters has been studied. Numerical calculations of effective dipole moment parameters for the ν 2 and ν 4 bands of 12 CH 4 have been performed. There is reasonable agreement between calculated and fitted…
Dielectric spectroscopy and molecular dynamics of methylene chloride CH2Cl2
1991
Abstract Precise measurements of the complex permittivity of methylene chloride (CH 2 Cl 2 ) at 293 K have been made at frequencies in the range 50–310 GHz. These, when combined with earlier results, have made possible a determination of the complex permittivity over the entire zero to THz frequency region. These results show a distribution of dielectric relaxation times. The value of the Cole-Cole distribution parameter, α, was 0.03 and that of the relaxation time, τ, was 2.07 ps. A comparison of the power absorption, A (ω), spectra of pure methylene chloride with the normalized dilute solution spectra shows that: (a) the integrated absorption intensity of the pure liquid is 20% greater th…
Balance of payments crises and fiscal adjustment measures
1991
A model with optimizing firms and consumers is used to explore the effects of unannounced and preannounced fiscal adjustment policies that are intended to prevent an impending balance of payments crisis. It is shown that preannouncement unambiguously raises the required fiscal adjustment effort so that, from the government's point of view, “cold turkey” is the preferable policy. The effect of preannouncement on the private sector's adjustment cost is ambiguous since preannouncement induces an externality which may either benefit or harm the private sector, depending on the nature of the measure that is preannounced.
Investigation of the (d, p)-reaction on136, 132Xe in inverse kinematics
1991
The one-neutron transfer reactions d(132,136 Xe, p)133,137 Xe have been investigated in inverse kinematics with xenon beams incident on deuterium loaded titanium targets. The angular distributions of the protons, measured with a detector array of 100 PIN-photodiodes, have been analyzed using standard DWBA. Generally, good agreement is obtained with results previously obtained in reactions induced by light-ion beams.
A remarkable rearrangement during reaction between triazolopyridinium ylides and dimethyl acetylenedicarboxylate
1991
Abstract The ylides from 2-acylmethyltriazolopyridinium salts ( 1 ) react with dimethyl acetylenedicarboxylate in toluene solution to give the 7-pyrroleninylpyrazolo[1,5-a]pyridines ( 5 ).
Dielectric investigations of pure and mixed fluorocarbons in their condensed phases
1991
We review recent work and present new results on the liquid and solid fluocarbons CMF3 with M = H, F, Cl, Br, CH3, and CF3. The pure compounds as well as several series of binary mixtures were investigated using dielectric measurements. The permittivities of the non-hydrogenatcd non-polar and polar liquids could be described using the Clausius-Mosotti and the Onsager equation, respectively. In CHF3 and C2H3F3 hydrogen bridging leads to deviations from this simple behavior. The trends in the miscibility of four series of fluorocarbon mixtures are in qualitative accord with regular solution theory. The geometrical shapes of the compounds dominate the degrees of order below their melting point…
Physical model, theoretical aspects and applications of the flight of a ball in the atmosphere. Part I: Modelling of forces and torque, and theoretic…
1991
A model of the forces and the torque operating on a ball that is flying with rotation in the atmosphere of the Earth, and the resulting system of ordinary differential equations, are derived from mechanics and aerodynamics. The system of equations allows the theoretical aspects of the flight of a ball, such as the boundedness of its kinetic energy, the curvature of the orbit or the velocity function, to be investigated using certain transformations of the variables. The solutions of the corresponding ordinary or boundary value problems, computed numerically, are used to treat certain tasks in international ball games, for example, the maximum and minimum velocities of a volleyball service.
Organochlorine residue analysis of commercial milks by capillary gas chromatography
1991
The determination of organochlorine pesticides and polychlorinated biphenyls in milks requires the use of efficient extraction methods. A rapid procedure has been developed, based on extraction of organochlorine residues from milk on to octadecylsilica solid phase extraction cartridges and elution with hexane. The addition of different organic solvents to the milk before solid phase extraction has been studied. The use of methanol to disrupt the fat globules enables almost complete recovery of the residues with minimum extraction of fatty substances. Recovery experiments were performed for eighteen compounds present at ppb levels in whole, two per cent, and skimmed milks. The average recove…
Acute changes of systemic parameters in tumour-bearing rats, and of tumour glucose, lactate, and ATP levels upon local hyperthermia and/or hyperglyca…
1991
Arterial blood pressure and relevant parameters of the arterial blood (O2 and CO2 tensions, pH, haematocrit, serum electrolytes and osmolality) were determined in tumour-bearing rats upon local hyperthermia (HT) and/or hyperglycaemia (HG). Tumour heating was performed in a saline bath (44 degrees C) for 120 min; hyperglycaemia was induced by i.v. infusion of 40% glucose solution for 150 min [blood glucose levels: 35-40 mM during heating; total amount of glucose: 1.19 g/100 g body wt.; infusion rates: 0.31 ml (100 g body wt.)-1 min-1 for 2 min, 0.02 ml (100 g body wt.)-1 min-1 for 88 min, and 0.01 ml (100 g body wt.)-1 min-1 for 60 min]. Immediately after treatment, glucose, lactate and ATP …
On the problematic nature of vitamin E requirements: net vitamin E
1991
The requirement for vitamin E is closely related to the dietary intake of polyunsaturated fatty acids (PUFA). By the protective mechanism to prevent PUFA from being peroxidized, vitamin E is metabolically consumed. In addition, PUFA impair the intestinal absorption of vitamin E. Therefore PUFA generate an additional vitamin E requirement on the order of 0.6, 0.9, 1.2, 1.5, and 1.8 mg vitamin E (RRR-alpha-tocopherol-equivalents), respectively, for 1 g of dienoic, trienoic, tetraenoic, pentaenoic, and hexaenoic acid. For this reason, the gross vitamin E content of food containing PUFA does not allow an evaluation of this food as a source of vitamin E. A suitable measure is the net vitamin E c…
Volatile compounds in strawberry jam : influence of cooking on volatiles
1991
Volatile constituents of strawberry jam were identified and their olfactive impact estimated by HRGC effluent sniffing. Amounts of volatiles in jam were only slightly affected by addition of sugar, but were closely related to design of the cooker and to the pressure used. Losses by evaporation during cooking were studied. Different types of behaviour were observed for the specific aromatic components. Cooker design largely influenced flavor losses at low pressures. Condensation of vapors during cooking and incorporation of the condensate in pectin solutions could result in a more flavorfull product.
Synthesis and spectroscopic characterization of organotin derivatives ofN-benzoylglycylglycine
1991
Di- and tri-organotin derivatives of N-benzoylglycylglycine (HBzGlyGly) were synthesized and characterized by infrared, 1H, 13C NMR and 119Sn Mossbauer spectroscopy. Diorganotin derivatives appear to be dimer distannoxanes ([R2SnBzGlyGly]2O)2 (R = CH3, n-C4H9, n-C8H17) with a ladder-type structure where tin atoms are five-coordinated and N-benzoylglycylglycine alternatively acts as a unidentate or bridging bidentate ligand through the carboxylate group. For triorganotin derivatives R3SnBzGlyGly (R= CH3, n-C4Hg) we propose a polymeric structure where N-benzoylglycylglycine bridges planar SnC3 units through the carboxylate group.
Visible polarized light transmission spectroscopy of the electro-optic switching behaviour of surface stabilized ferroelectric liquid crystal cells
1991
Abstract We present in this paper an experimental and theoretical modelling study of the switching characteristics and electro-optic behaviour of chevron surface stabilized ferroelectric liquid crystal cells with planar (low pre-tilt) and non-planar (high pre-tilt) surface conditions. The visible polarized light transmission spectra were taken of the cells with glass plates coated with films of either rubbed polymer or obliquely evaporated silicon monoxide (SiO) at various applied voltages and in various stages of switching and compared with the theoretical values calculated numerically based on our director-polarization structure model for the aforementioned cells. The results provide evid…
Effect of rat plasma high density lipoprotein with or without apolipoprotein E on the cholesterol uptake and on the induction of the corticosteroid b…
1991
Abstract High density lipoprotein (HDL) has been shown to induce the cellular accumulation of cholesterol esters and the biosynthesis of 21-hydroxysteroids (corticosteroids) newborn rat adrenocortical cells cultivated in serum-free medium. In order to identify the component(s) of HDL responsible for these effects, we investigated the ability of rat HDL subfractions and HDL with or without apolipoprotein E to deliver cholesterol to cells and to stimulate the steroid biosynthetic pathways in adrenal cultured cells. The total cholesterol uptake from HDL 2 was greater than that observed with HDL rich in apolipoprotein E (HDL 1 and HDL c ). Furthermore, the increase of the ratio between 21-hydro…
Estimation of the size of liposomes by modified HDC
1991
Internal calibration in modified hydrodynamic chromatography has been realized by the approach of Prieve and Hoysan, i.e. the use of polystyrene monodisperse latexes to evaluate the equivalent capillary radius, R. The value obtained has been used to estimate the average sizes of a variety of liposome samples from egg yolk lecithin.
Quantitative analysis of opsonophagocytosis and of killing of Candida albicans by human peripheral blood leukocytes by using flow cytometry
1991
We describe a simple, rapid, automated procedure for measuring opsonophagocytosis and killing of Candida albicans by human peripheral blood leukocytes. Yeast cells are labelled by allowing uptake and cleavage of membrane-permeable bis-carboxyethyl-carboxyfluorescein pentaacetoxymethylester to its membrane-impermeable fluorescent derivative bis-carboxyethyl-carboxyfluorescein. The yeast cells are added to cell-rich plasma obtained after dextran sedimentation of erythrocytes. Opsonophagocytosis and killing are quantified by using automated fluorescent cell analysis, and the following parameters can be obtained: (i) relative percentage of phagocytes that participate in opsonophagocytosis, (ii)…
A finite element analysis of high- speed metal forming processes
1991
International audience
Gravitational scattering on a global monopole
1991
The scattering amplitude and the total scattering cross section of massless particles propagating in the gravitational field of a global monopole are derived. We find that the physical signature of such defects is a ringlike angular region where the scattering amplitude is very large. The size of this ringlike region is determined by the ratio of the global monopole mass to the Planck mass and its appearance stems from the fact that the metric of the global monopole is not asymptotically flat but rather displays the characteristic spherical angle defect. The situation is therefore very much reminiscent of scattering in the gravitational field of the cosmic string.
ɛ-type contribution to baryon asymmetry from colored Higgs triplets
1991
In scenarios where the cosmological baryon asymmetry is generated in the decay of heavy colored Higgs triplets at the one-loop level (at least two triplets are needed), it is shown that in addition to the conventional triangle loop ({epsilon}{prime}-type effect), a new kind of diagram must be considered. This new type of diagram has its origin in the mixing of the two Higgs fields ({epsilon}-type effect). The mixing of the two Higgs fields violates {ital CP} provided they have at least two common decay channels. For small mixing angles, the new contribution can be bigger than the conventional one.