showing 36 of ~574560 from 574555 documents
Quantitative separation of Trichoderma lipid classes on a bonded phase column.
1992
Bond Elut aminopropyl columns were used to purify the different lipid classes of Trichoderma harzianum and Trichoderma viride. This methodology permitted good separation of the fungal lipid classes in less time than traditional techniques. The incorporation of [1 (14)C]linoleic acid into neutral lipids, free fatty acids and phospholipids was quantified for both strains. The fatty acid profile of the different lipid classes of these fungal strains was determined as a function of culture time.
Evidence of a contralateral motor influence on reciprocal inhibition in man
1992
The role of contralateral movement on both H reflex and reciprocal inhibition was studied. In normal men H reflex was induced by median nerve stimulation. Reciprocal inhibition was achieved through stimulation of the antagonist radial nerve. On this basis the effects of contralateral arm movement were analized. Furthermore the putative influence of exteroceptive origin was also verified by means of digit stimulation. Results showed that contralateral arm movement did not affect H reflex amplitude; on the contrary, it was able to enhance reciprocal inhibition induced by extensors on flexors. Study of cutaneous afferents demonstrated that contralateral digit stimulation failed to elicit modif…
Bedeutung der Ganzkörper-Skelettszintigraphie im Rahmen des Staging von Malignomen im HNO-Bereich*
1992
Concerning malignant tumours of the oral cavity, pharynx and larynx, bone metastases are in general rarely seen. For the specification to which patients the whole body bone scintigraphy as detection method should be applied, the findings of 370 patients were analysed retrospectively. In respect of primary staging, bone metastases could be found by scintigraphy in only 1.4% of the patients. On the other hand, there was a detection rate of 12% during the further course of the disease, especially in case of clinical symptoms pointing at spreading metastases or in tumour recurrences. Nevertheless, positive scan findings which were not due to metastases could be found in both groups with equal f…
Current status of phosphodiesterase inhibitors in the treatment of congestive heart failure.
1992
The phosphodiesterase inhibitors have been recognised as potent inotropic and vasodilating drugs. In acute congestive heart failure they increase cardiac output, decrease left pulmonary capillary wedge pressure, and reduce total peripheral resistance with an improvement in loading conditions of the failing heart. Their potency in reversal of symptoms of acute congestive heart failure is quite similar to, or even better than, treatment with intravenous catecholamines and sodium nitroprusside. In chronic congestive heart failure, however, these agents increase mortality and have deleterious effects in the outcome of patients with severe left ventricular dysfunction.
Deeply bound pionic states with the (? ?,?) reaction
1992
We study the reactionΣ− +A→Λ + (Aπ−) with the π− bound in the nucleus, as a means of producing deeply bound pionic states in nuclei, so far unobserved. The reaction is similar to the (n, p) reaction but, because of theΣ−, Λ mass difference, it allows the reaction to occur with smaller momentum transfer, thus increasing the transition probability and reducing the effects of distortion. The ratios of signal to background are one to two orders of magnitude better than in the (n, p) reaction.
Pancreatic enzymes in chronic renal failure and transplant patients.
1992
The aim of the present study was to determine the frequency and degree of elevated serum levels of Total Amylase (TA), Pancreatic Amylase (PA), and Lipase (L) activity in patients with chronic renal failure (CRF) on conservative therapy; CRF on periodical hemodialysis (HD); in renal transplant (RT) and in a control Group (C). Mean values were significantly higher in all groups than Group C for TA (p < 0.005), PA (p < 0.0001) and L (p < 0.0001). A statistically significant correlation was found between TA and L vs creatininemia values in CRF patients, but only up to a certain level (creatininemia < 6 mg %) (p < 0.03 and p < 0.05), above which there was no correlation. The enzyme most frequen…
Theory of orientational glasses models, concepts, simulations
1992
Abstract This review describes the various attempts to develop a theoretical understanding for ordering and dynamics of randomly diluted molecular crystals, where quadrupole moments freeze in random orientations upon lowering the temperature, as a result of randomness and competing interactions. While some theories attempt to model this freezing into a phase with randomly oriented quadrupole moments in terms of a bond-disorder concept analogous to the Edwards-Anderson model of spin glasses, other theories attribute the freezing to random field-like terms in the Hamiltonian. While models of the latter type have been studied primarily by microscopic molecular field-type treatments, the former…
Relative sensitivity of four noninvasive methods in assessing systolic cardiovascular effects of isoproterenol in healthy volunteers.
1992
Study objective The study was performed to evaluate the relative sensitivity of various noninvasive methods to detect and describe the systolic cardiovascular effects of stepwise increasing doses of isoproterenol: two-dimensional left ventricular echocardiography (main variable, ejection fraction), ACVF (attenuation compensated volume flow)–dual-beam Doppler echoaortography (time-averaged mean velocity), electrical impedance cardiography [(dZ/dtmax)/RZ index], and systolic time intervals from mechanocar-diography (PEP and QS2c). Methods Isoproterenol was administered by constant rate intravenous infusion in consecutive steps of 0.1, 0.2, 0.4, 0.75, and 1.5 µg/min (each for 15 minutes). Sali…
Towards a "perfect" Penning trap mass spectrometer for unstable isotopes
1992
A Penning trap mass spectrometer has been set up at the on-line isotope separator ISOLDE/CERN for the mass determination of unstable heavy isotopes. The spectrometer should fulfil the following requirements: capture of external ions in high efficiency, high resolving power and accuracy, general applicability to all elements and isotopes available at the on-line facility.
Heinrichs Skuja's contribution to phycological research in Latvia
1992
A review of H. Skuja's phycological research carried out in Latvia during the period 1924–1944. It is due to his research that the number of algal species identified in Latvia increased from 200 to 2300. 50 species and varieties, and 9 genera were described by him as new.
Nuclear moments and the change in the mean square charge radius of neutron deficient thallium isotopes
1992
The hyperfine structure, isotope and isomeric shifts in the atomic transition 6p 2 P 3/2−7s 2 S 1/2, λ=535 nm have been measured for theI=7 andI=2 states of190, 192, 194, 196Tl; theI=1/2 andI=9/2 states of191Tl and the I=7 isomer of188Tl. The thallium isotopes were prepared as fast atomic beams at the GSI on-line mass separator following fusion reactions and — in some cases — subsequentβ-decay. The nuclear dipole moments, electric quadrupole moments and the change in the nuclear mean square charge radius are evaluated. Theuu-isotopes show an isomeric shift which changes sign between192Tl and194Tl.
A NEW AREA OF ALKALINE ROCKS IN EASTERN PARAGUAY
1992
Alkaline rocks can be found in three major areas (northern, northeastern and central-eastern) of Eastern Paraguay. On die basis of geographic distribution and tectonic association, Livieres & Quade (1987) proposed inclu- sion of these outcrop areas different alkaline provinces: Alto Paraguay, Amambay and Central, respectively (Fig. 1). Presently, only the Central Province, clustering the largest number of occurrences, is the subject of systematic investigation. Available information on the Alto Paraguay and Amambay rocks is still scarce.
Geochronology and palaeomagnetism of a late Proterozoic island arc terrane from the Red Sea Hills, northeast Sudan
1992
Abstract Size fractions and single grains of zircon, hornblende and biotite have been dated to define the formation age and thermal history of the northern Haya Terrane (NHT), a late Proterozoic island arc terrane of the Red Sea Hills (RSH), northeast Sudan. U Pb and 207 Pb/ 206 Pb zircon data for acidic volcanics and granitoid rocks bracket the time of formation of the NHT between 887 ± 20 and 854 ± 9 Ma. 40 Ar/ 39 Ar hornblende and biotite ages of a gabbro near Suakin suggest passage through the argon closing temperature for hornblende at about 841 ± 4 Ma and 782 ± 6 Ma for biotite. The hornblende age is considered to be representative of the age of magnetic blocking and, hence, the age o…
A computer method for estimating volumes and surface areas of complex structures consisting of overlapping spheres
1992
A PASCAL program which calculates volumes and surface areas of structures consisting of overlapping spheres is designed. The calculation is done by modelling the structure in the memory of a computer and then scanning the memory bit- or bytewise. A brief discussion of the error is presented, and an example for testing the algorithm is provided.
RESOLVING AMBIGUITIES IN ORIENTATION, MOTION, AND DEPTH DOMAINS
1992
Three different perceptual systems—orientation, motion, and depth—can recover a global perceptual organization from spatially correlated random multielement patterns. In all three cases the global structure composed of random elements is evaluated by mechanisms performing measurements in the energy domain within appropriately defined local space—time areas. The selective increase in energy of one fraction of the elements may dramatically change the whole perceptual organization of the stimulus. In specially devised patterns one and the same element can belong to two or more separate perceptual organizations, the perceptual salience of one of which can be reinforced by a luminance increment…
Search for CP violation in ZmF ττ
1992
Abstract Using the 18.8 pb−1 of data accumulated at LEP in 1990 and 1991 with the ALEPH detector, a direct test of neutral current CP-invariance is performed by a search for CP-odd correlations in Z decays to τ pairs where both τ decay modes are identified. No evidence for CP-violation is observed. The weak dipole moment of the τ has been measured to be dτ(mZ) = (1.3 ± 1.4 ± 0.1) × 10−17 e·cm which results in an upper limit on the weak dipole moment of |dτ(mZ)| ⩽ 3.7 × 10−17 e·cm with 95% confidence level.
Phaenocompsopogon pustulatus n.gen.n. sp., a calcareous alga from the lacustrine rotliegend of the Saar-Nahe Basin (SW-Germany)
1992
Phaenocompsopogon pustulatus n. gen. n. sp. is a calcareous freshwater alga, probably of rhodophycean affinity. The fossils are mainly known from one locality in the Lower Permian of the Saar-Nahe Basin. The algal remains form a packstone in the Reckweilerhof-Bank of the Altenglan Formation. The simple thallus branches irregularly y-shaped and is covered with abundant pustules. An axial canal is characteristic, as are distinct cell features of an inner and outer cortex surrounding a structureless medulla. Most fossils are silicified and often three-dimensionally preserved. The algae lived in a wave-dominated environment, probably in offshore shallow water. The limited occurrence suggests sp…
Hormone Effects on the Membrane Potential and on Sucrose-Induced Depolarization of Young <italic>Citrus</italic> Leaves
1992
Xenobiotic-metabolizing enzyme activities in hybrid cell lines established by fusion of primary rat liver parenchymal cells with hepatoma cells
1992
1. The activities of xenobiotic-metabolizing enzymes were determined in hybrid cell lines (hepatocytoma, HPCT) which have been established by fusion of liver parenchymal cells from adult rat (PC) with cells from a Reuber hepatoma cell line (FAO). 2. Cytochrome P450 was not measurable spectrophotometrically in FAO and HPCT. P450-dependent conversion of testosterone was below the detection limit in FAO and only marginally present in HPCT. 3. Microsomal and cytosolic epoxide hydrolase, glutathione S-transferase and phenol sulphotranserase were low or even below detection limit in FAO. These enzyme activities were significantly higher in HPCT and correspond to about 1-10% the activities measure…
P- versus S-wave at rest in LH2
1992
Abstract The annihilation p p →π 0 π 0 was measured for antiprotons stopped in liquid hydrogen (LH2). This reaction is only allowed from odd angular momentum states of the p p - atom . The resulting branching ratio BR ( p p →π 0 π 0 ) LH 2 =(6.93±0.22 stat ±0.37 syst )×10 −4 , combined with a previous measurement of the branching ratio BR ( p p →π + π − ) 2 P in gas from the 2P-state of p p suggests a fraction of P-wave annihilation in LH2 of (28.8±3.5)%, much larger than the values obtained from other annihilation channels. A method of reconciling the contradictory results is discussed.
Competition between binary reactions and fusion in heavy-ion collisions at the Coulomb barrier
1992
Mass and charge distributions for binary reaction channels have been measured for the reactions86Kr with76Ge,104Ru and130Te at the Coulomb barrier using chemical separations andγ-ray spectroscopy. These systems span the region where dynamical hindrance to complete fusion sets in. The binary reactions can be subdivided into two components associated withi) reflection from the outer potential barrier (quasielastic), andii) reseparation after passing the barrier (complex reactions). The sum of complex-reaction channels and evaporation residues from complete fusion can be reproduced by a barrier passing calculation. The fraction of the barrier passing flux leading to reseparation increases from…
Phospholipase D in heart: basal activity and stimulation by phorbol esters and aluminum fluoride
1992
Evidence for a general role of phospholipase D in signal transduction is accumulating. In the present study, the activity of the enzyme was investigated in heart tissue under basal conditions and after addition of phorbol esters or aluminum fluoride (AlF inf4 sup− ; 10 mM NaF plus 10 μM AlCl3). Atria of rats and chickens were incubated with [3H]-myristic acid in order to label preferentially phosphatidylcholine. Under basal conditions, the tissues generated choline and phosphatidic acid (PtdOH), the primary catalytic products of phospholipase D. When 0.5 or 2.0% ethanol was present, [3H]-phosphatidyl-ethanol (PETH) was rapidly formed at the expense of [3H]-PtdOH. This transphosphatidylation…
Experimental lifetime of the metastable 5D 3/2 state in Ba+
1992
A discrepancy exists between theoretical and experimental lifetimes of the metastable 5D3/2 state in Ba+. In order to redertermine that lifetime, we probe the population of the metastable 5D3/2 state of a Ba+ ion cloud stored in a Paul ion trap in the presence of He buffer gas as the function of time delay after pulsed laser excitation of this state. The measured decay rates at different buffer gas pressures are extrapolated to zero pressure and we obtain a radiative decay time of 48.0±5.9 s. This is not in agreement with theoretical predictions of about 80 s, but reduces the discrepancy from a previously reportet experimental value of 17.5 s. If the possibility of finestructure mixing to a…
Acid Dnase Activities In Peripheral, Mononuclear Blood Cells: A Possible Parameter To Detect Proliferating Cell Populations
1992
After electrophoresis in DNA -containing polyacrylamide gels, two acid DNase activities can be detected in peripheral, mononuclear cells of the human blood. One of these acid DNase activities correlates with cell proliferation; its isoelectrical point is at pI 7.4. By means of this DNase activity, a quantity of less than 1% leukemic cells can be detected. The increased acid DNase activity can indicate the proliferation of malignant cell populations and possibly the proliferation of cell populations during immunological reactions
Water structure in water/AOT/n-heptane microemulsions by FT-IR spectroscopy
1992
Abstract FT-IR spectra in the OH stretching region of water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/n-heptane microemulsions as a function of the water/AOT molar ratio (R) and of the weight fraction (φ) of the micellar phase have been recorded at 25°C. After elimination of the unwanted CH contribution and correction for the water concentration, the shape of the normalized OH bands has been found to be dependent on R and practically independent of φ. The analysis of these bands in terms of “bound” and “bulk” water (representing, as a first approximation, the two water domains within the water pool) allowed the evaluation of the fraction (α) of the “bound” water as a function of R. A…
Intravitreal foscarnet for cytomegalovirus retinitis in a patient with acquired immunodeficiency syndrome.
1992
We treated a patient who had acquired immunodeficiency syndrome and cytomegalovirus retinitis of the left eye. After anesthetic had been topically administered, the patient received intravitreal injections of 1,200 micrograms of foscarnet. Plasma and vitreous foscarnet levels were measured by high-performance liquid chromatography. Systemic absorption of the drug was not evident. Elimination half-life from the vitreous after one injection was 54.0 hours. Vitreous levels remained above the mean 50% inhibition value for cytomegalovirus for approximately 56 hours and above the mean inhibition value for human immunodeficiency virus for approximately 241 hours. The patient's visual acuity improv…
Modelling of light transmittance and reflectance in flat fluidized photoreactors
1992
In recent years several photon induced chemical reactions involving the use of a solid catalyst have been studied. Flat fluidized beds have proved to be promising devices for carrying out these photocatalytic reactions. There is therefore a need for the modelling of light interactions within such kinds of photoreactors. In this paper, a phenomenological model is proposed for simulating the light transmission and reflection in flat fluidized gas-solid photoreactors. A detailed description of the model is presented. The model predictions were compared with experimental data and a satisfactory agreement was found. Correlations were also suggested for the estimation of model parameters. Depuis …
Progesterone increases basal 3',5'-cyclic adenosine monophosphate formation and down-regulates the agonist-induced inositol phosphates generation in …
1992
Whether the placenta is a target tissue for estrogens and progesterone, and their putative mechanism of action, is still a controversial question in the literature. The effect of progesterone and estradiol on 3′,5′-cyclic adenosine monophosphate (cAMP) and inositol phosphates generation in human term placenta was investigated. Placental explants were incubated in vitro for up to 48 h in the absence and in the presence of estradiol, progesterone or both steroids (0.1 μmol/l final concentration in all cases), and were stimulated with terbutaline, a β-adrenergic agonist, (0.1 mmol/l) or angiotensin II(1 μmol/l), The cAMP content was measured by a competitive protein binding assay, and the gene…
Caractérisation des tôles Fer-Silicium en régime dynamique pulsant
1992
Using a characterization method based on the Epstein's frame principle, we study the evolution of the magnetic and losses characteristics of NO Fe-Si sheets with respect to the fundamental frequency, the temperature and the wave front under time-variable sinusoidal or constant wave front trapezoidal magnetic flux density. At last, we modelise the evolution of the iron losses with respect to these parameters, except the temperature
Contribution of thallium-201-SPECT to the grading of tumorous alterations of the brain
1992
Single photon emission computed tomography (SPECT) with thallium-201-chloride (201Tl) was used in 22 patients to assess the grade of malignancy of brain tumors. Low- and high-grade malignant gliomas could be well differentiated by calculating the Grade Index (GI), i.e., 201Tl uptake in the tumor area relative to a contralateral brain region. Low-grade gliomas (WHO-grade I-II) usually showed a GI of1.5. Tumors classified histologically as high-grade malignant (WHO-grade III-IV) had GI values greater than 1.42 and a mean value of 1.89. Until labelled amino-acid tracers for gamma-cameras become commercially available, thallium-201 brain-SPECT can provide an independent and complementary method…
Autosomal dominant polycystic kidney disease—in vitro culture of cyst-lining epithelial cells
1992
The major form of autosomal dominant polycystic kidney disease (ADPKD) in humans is linked to the PKD1 gene on chromosome 16p. The identity of the gene and the underlying pathogenetic mechanisms are not yet defined. Cyst-lining epithelial cells derived from a polycystic kidney were successfully grown in culture and designated MZ-PKD-1 cells. By linkage analysis, the related pedigree of the nephrectomized patient could be linked to the PKD1 gene on chromosome 16p. Thus, these cells exhibit the genotype of a mutated PKD1 gene and represent an in vitro culture model for ADPKD involving chromosome 16p. The antigenic phenotype was characterized immunohistologically by epithelial differentiation …
Resolution of nuclear ground and isomeric states by a Penning trap mass spectrometer.
1992
Ground and isomeric states of a nucleus have been resolved for the first time by mass spectrometry. Measurements on $^{78}\mathrm{Rb}^{\mathit{m},}$g and $^{84}\mathrm{Rb}^{\mathit{m},}$g were performed using a tandem Penning trap mass spectrometer on-line with the isotope separator ISOLDE/CERN. The effects of ion-ion interaction were investigated for two ion species differing in mass and stored simultaneously in the trap.
Sequence stratigraphy and paleo-oceanography of an open-marine mixed carbonate/siliciclastic succession (Late Jurassic, Southern Germany)
1992
The Late Jurassic epicontinental sea of South Germany protruded far to the North forming a wide bay which was rimmed by shallow-water platforms (Swiss and French Jura). This wide shelf is characterized by extensive downslope mud accumulations including siliceous sponge buildups. The bioherms are aligned along the more pericontinental parts of this shelf, which graded to the South into the Helvetic Basin of the Tethys Ocean.
Contribution of both ?- and ?-adrenoceptors to the inotropic effects of catecholamines in the rabbit heart
1992
The functional role of alpha-adrenoceptors was investigated in different parts of the rabbit heart. Phenylephrine (PE) caused a marked increase in force of contraction (Fc) and a prolongation of the action potential (AP) in preparations from the left atrium and the right ventricle. The response was less pronounced in the right atrium and in the left ventricle, whereas APs of spontaneously beating sinoatrial preparations remained completely unchanged. Phentolamine as well as the diesters phorbol 12,13 dibutyrate (PDBu) or 12-O-tetradecanoyl-phorbol-13-acetate (TPA) eliminated the effects of PE. The contribution of alpha-adrenoceptors to the effects of adrenaline (Adr) and noradrenaline (NA) …
The Tolerability of Nilvadipine Compared to Nifedipine in Patients with Essential Hypertension
1992
In one multicenter, double-blind study, 659 hypertensive patients were treated for 16 weeks with either nilvadipine (n = 326) or nifedipine (n = 333). The major objective of the study was to compare the compatibility of the two calcium antagonists with regard to hepatic compatibility and side-effect profiles. The dosages were chosen so that the effective blood pressure reduction in both groups was equally good (mean decreases in systolic pressure of 27 +/- 12 mm Hg with nilvadipine and 26 +/- 15 mm Hg with nifedipine, and in diastolic pressure of 18 +/- 6 mm Hg with nilvadipine and 19 +/- 7 mm Hg with nifedipine). The mean heart rate was slightly lowered by about 2 beats/min by both substan…
Los estudios de historia agraria medieval en el País Valenciano
1992
Los estudios de historia agraria sobre el País Valenciano presentan tres problemas iniciales: menos documentación que la disponible para los tiempos modernos; la juventud de las investigaciones y una tradición de edición en revistas locales y medievales, pero no especializadas en historia agraria. Las principales líneas de investigación actualmente están dedicadas a la construcción de la nueva sociedad cristiana en el siglo XIII, con especial interés a los problemas de colonización y la sociedad rural, la historia social del campesinado, con aspectos a los problemas privados y familiares; a los problemas del poder local en el interior de las comunidades rurales y su estratificación; a la re…