showing 36 of ~574560 from 574555 documents
Voltammetric behavior of berenil.
1993
Abstract Berenil is reduced on mercury drops electrode in buffered aqueous media. The reduction of —N=N— group is controlled by diffusion. Polarographie waves are of analytical usefulness. The hydrogen discharge is favored by the basic centers of the molecule in Co(ll)/ammonia-buffered media.
Injective Fitting sets in automorphism groups
1993
Pion interaction with the trinucleon up to the eta production threshold
1993
Pion elastic, charge exchange scattering and induced eta production on the trinucleon systems are investigated in a coupled-channels approach in momentum space with Fadeev wave functions. The channel $\pi N \rightarrow \eta N$ is included using an isobar model with S-, P-, and D-wave resonances. While the coherent reactions like $^3$He($\pi,\pi)^3$He can be reasonably well reproduced up to $T_{\pi}$=500 MeV, large discrepancies appear for the incoherent processes, $^3$He($\pi^-,\pi^0)^3$H and $^3$He($\pi^-,\eta)^3$H at backward angles and energies above $\Delta$-resonance. In the forward direction the $(\pi,\eta)$ calculations underestimate the experimental measurements very close to thresh…
Improved Mesophyll Protoplast Culture and Plant Regeneration in Arabidopsis thaliana (L.) Heynh., Genotype Landsberg Erecta
1993
Summary The response of in vitro cultured Arabidopsis thaliana mesophyll protoplasts was investigated with the aim of characterising the crucial factors that affect plating efficiencies and plant regeneration. We selected the genotype Landsberg erecta, which is frequently used for genetic studies, but which is known to respond poorly in protoplast culture. Factors permitting vigorous vegetative growth of the donor plants, i.e. short light period and avoidance of high temperature, were found to be advantageous. Selection of competent leaves and fractionation of protoplast populations indicated that predominantly protoplasts derived from still expanding, yet not highly immature mesophyll cell…
Physiological pharmacokinetic model for ceftazidime disposition in the rat and its application to prediction of plasma concentrations in humans
1993
Abstract A physiological pharmacokinetic model for the disposition of ceftazidime in the rat was developed. The model is composed of 10 compartments which represent most of the organs and tissues of the body. Ceftazidime concentration-time profiles in the organs and tissues represented in the model were simulated and compared with the observed concentration-time data after i.v. administration of 5 and 20 mg of antibiotic. The model gave an acceptable description of the observed data. The steady-state volume of distribution and total clearance of ceftazidime in healthy humans predicted from data obtained in the rat (0.21 l/kg and 113 ml/min, respectively) were similar to the values reported …
Surfaces non-orientables de genre deux
1993
The existence of nonorientable complete minimal surface of genus two, one end and total curvature −2π(2n+3),n≥3 is proved in this paper.
Effects of Ca2+ channel antagonists in guinea-pig normal and skinned gall bladder.
1993
CaCl2 (0.01-50 mM, in K(+)-depolarized tissues), KCl (0.1-100 mM) and acetylcholine (1 nM-10 mM) produced concentration-dependent contractions of guinea-pig isolated gall bladder. Nifedipine (1-100 microM), verapamil (1-100 microM), diltiazem (1-100 microM), cinnarizine (1-100 microM), and flunarizine (1-100 microM) each produced a concentration-related inhibition of the log concentration-effect curve for CaCl2. The rank order of potencies of these antagonists, measured as the IC50 against Ca2+ (50 mM)-induced contraction of depolarized gall bladder, was diltiazem (0.25 microM)or = verapamil (0.8 microM) approximately nifedipine (1.2 microM)cinnarizine (25 microM) approximately flunarizine …
How young Europeans sleep.
1993
This study investigated sleeping habits, difficulties in being able to fall asleep and their connections to self-reported health conditions, as well as other selected health behaviours and use of leisure time, among 11-16 year old Europeans from 11 countries. The study was part of a larger, comparative, WHO coordinated project on the health and life-style of school children (Health Behaviour of School Age Children--A WHO Cross-National Survey, The HBSC Study). In most of the countries, research data were collected from samples representative of the whole country. Using a standardized survey questionnaire, the data were collected anonymously in schools. Altogether 40,202 students responded t…
Joint angular decay distributions in exclusive weak decays of heavy mesons and baryons
1993
We present the results of a comprehensive analysis of the angular decay distributions occurring in the weak exclusive decays of the lowest lying charm and bottom mesons and baryons. We deal with both semileptonic and nonleptonic decays and discuss various decay channels and their subsequent cascade decay chains including lepton mass effects. In the case of baryons we include polarization effects for the parent charm or bottom baryon. We list in table form general formulae which allow one to write down the joint angular decay distributions for the cascade decaysA→B(→b 1+...+b n )+C(→c 1+...+c n ), for all spin casess A ≤1/2 ands B ,s C ≤3/2 for the prominent decays ofB andC. Two examples inv…
Cortical neurons selectively inhibit MHC class II induction in astrocytes but not in microglial cells.
1993
Astrocytes have been shown to act as potent accessory cells for MHC class II-restricted T cell responses in vitro after treatment with interferon-gamma. In contrast, even under conditions of severe central nervous system (CNS) inflammation, they seem to express little, if any, class II molecules in vivo. Thus the role of astroglial cells as accessory cells in immune responses in the CNS remains to be determined. We have studied neuron--glia interactions with respect to induction of MHC class II molecules. Surprisingly, in a co-culture system, viable neurons inhibited the induction of class II restriction elements on astrocytes. This effect was only observed when neurons had contact to astro…
Mechanism in allergic contact dermatitis.
1993
Quadratic Lattices in Function Fields of Genus 0
1993
Bochner-Riesz means of functions in weak-L p
1993
The Bochner-Riesz means of order delta greater-than-or-equal-to 0 for suitable test functions on R(N) are defined via the Fourier transform by (S(R)(delta)f)(xi) = (1 - \xi\2/R2)+(delta)f(xi). We show that the means of the critical index delta = N/P - N + 1/2, 1 + infinity, to f(x) in norm and for almost every x in R(N). We also observe that the means of the function absolute value of x-N/p, which belongs to L(p,infinity) (R(N)) but not to the closure of test functions, converge for no x
Gasto público y crecimiento económico en la Restauración (1874-1923)
1993
Editada en la Universidad Carlos III Las aportaciones más recientes sobre la importancia del Estado en el crecimiento de la economía española durante la Restauración han señalado la reducida relevancia que el gasto público tenía en la determinación de la renta nacional. En este artículo se discute tal afirmación llegando a la conclusión de que tal afirmación infravaloraba la verdadera importancia del presupuesto, principalmente en relación con la producción industrial. Mediante la utilización de métodos econométricos se analiza la relevancia de las variaciones en los diferentes componentes del presupuesto en la variación de la Producción nacional. The most recent contributions on the releva…
The first authenticated example of triorganotin(IV) perchlorate complexes of some heterocyclic bases
1993
Abstract A convenient method is reported for the synthesis of some novel complexes of composition (R 3 SnL 2 ) ClO 4 where L represents pyridine, γ-picoline, 2,2′-bipyridine and 1,10-phenanthroline; and R n Bu or Ph. All of the new ionic complexes have been characterized by elemental analysis, molar conductance, infrared, multinuclear nuclear magnetic resonance ( 1 H, 13 C and 119 Sn) and 119 Sn Mossbauer spectroscopies. The complexes of composition (R 3 SnL 2 )ClO 4 exist both in solution and in the solid state with trans -trigonal bipyramidal structure where the R-groups occupy the equatorial positions while the ligands are in the axial position.
Familial insulin resistant diabetes associated with acanthosis nigricans, polycystic ovaries, hypogonadism, pigmentary retinopathy, labyrinthine deaf…
1993
Two sibs, whose parents are first cousins, had diabetes mellitus with hyperinsulinism, insensitive insulin receptors, and acanthosis nigricans. Both patients had pigmentary retinopathy, secondary cataracts, labyrinthine deafness, mental retardation, and cerebral atrophy. They were disproportionately short with relatively broad hands and feet and slightly coarse face. The young woman had secondary amenorrhea and polycystic ovaries and the boy gynecomastia and hypergonadotrophic hypogonadism. This appears to be the second family with a new autosomal recessive disorder differing from Alstrom syndrome by the presence of mental retardation and absence of renal insufficiency. Impaired insulin rec…
The Stockholm–Mainz ion trap project
1993
A new ion trap facility is described which is dedicated to studies of highly charged ions in a Penning trap. Such a trap will be connected to sources of highly charged ions, in particular the electron beam ion source CRYSIS, at the Manne Siegbahn Institute for Physics. The use of highly charged ions in a Penning trap increases the cyclotron frequency with a factor proportional to the charge which leads to a higher resolution. Also, the possibility to vary the charge state makes it possible to search for and identify different systematic effects. Thus, a substantial increase in accuracy can be expected. In addition, the combination of high charge state ions and a Penning trap allows new appl…
Pheromones inBlattella germanica andBlaberus craniifer (Blaberoidea): Glandular source, morphology and analyses of pheromonally released behaviours
1993
Females ofBlattella germanica andBlaberus craniifer produce a volatile sex pheromone attractive at a distance for conspecific males. During the emission of the pheromone, females ofB. craniifer adopt a typical calling posture; we never observe such a stance inB. germanica females. For both species, the glandular structures responsible for pheromonal production are located on the female pygidium. InB. germanica, the thickness of the glandular epithelium is clearly correlated with the attractiveness of females, being maximum for 13 day old females. The functions of the pygidial glands are discussed in both species.
Characterization of the length polymorphism in the A + T-rich region of the Drosophila obscura group species
1993
In the twelve Drosophila obscura group species studied, belonging to the affinis, obscura, and pseudoobscura subgroups, the mitochondrial DNA length ranges from 15.8 to 17.2 kb. This length polymorphism is mainly due to insertions/deletions in the variable region of the A + T-rich region. In addition, one species (D. tristis) possess a tandem duplication of a 470-bp fragment that contains the replication origin. The same duplication has occurred at least twice in the Drosophila evolutionary history due to the fact that the repetition is analogous to repetitions found in the four species of the D. melanogaster complex. By comparing the nucleotide sequence of the conserved region in D. ambigu…
A Co(III) complex of carbonic anhydrase inhibitor methazolamide and the amino-imino ‘aib’ ligand formed by reaction of acetone and ammonia
1993
Abstract Reaction of Co(NO 3 ) 2 ·6H 2 O with methazolamide {[ N -(3-methyl-5-sulfamoyl-1,3,4-thiadiazol-2(3 H )-ylidene)acetamide] (Hmacm)} and ammonia in acetone to produce [Co(methazolamidate)(2-methyl-2-amino-4-iminopentane) 2 (NH 3 )](NO 3 ) 2 ·2H 2 O is described. The ligand 2-methyl-2-amino-4-iminopentane (aib) is the product obtained from the condensation of two ammonia and two acetone molecules. The complex crystallizes in the monoclinic space group P 2 1 / c with a =16.713(5), b =9.180(1), c =20.273(1) A, β=97.44(4)° for Z =4. The R value is 0.081 for 2150 significant reflections. The Co(III) ion exhibits a nearly regular octahedral arrangement with the CoN bond distances in the …
Isolation, structural and toxicological characterization of three new mycotoxins produced by the fungusAureobasidium pullulans.
1993
3 substances, B1, B2, and E1 were isolated from culture medium extracts ofAureobasidium pullulans by reversed phase liquid chromatography and subsequent liquid chromatographic purification steps on silica gel.The 3 compounds inhibited the metabolism ofSaccharomyces cerevisiae and showed toxic effects in the growth inhibition test toEscherichia coli andBacillus subtilis.Elementary analysis and mass spectroscopical methods revealed sum formulas of C23H22O6, C22H20O6 and C24H28O3 for B1 B2, and E1 and molecular weights of 394, 380, and 364, respectively. Mass spectroscopical, UV-, IR-,(13)C-NMR, and(1)H-NMR-spectroscopical investigations revealed polycyclic, non-aromatic compounds containing s…
Human forms of neuronal ceroid‐lipofuscinosis (Batten disease): Consensus on diagnostic criteria, Hamburg 1992
1993
Investigation of a Killer Strain of Zygosaccharomyces Bailii
1993
Summary: The yeast Zygosaccharomyces bailii strain 412 was found to liberate a killer toxin (KT412) lethal to sensitive strains of Saccharomyces cerevisiae and Candida glabrata. Culture supernatants of the killer strain were concentrated by ultrafiltration and the extracellular protein was purified by gel filtration and ion-exchange chromatography. Gel filtration and SDS-PAGE of the electrophoretically homogeneous killer protein indicated an apparent molecular mass of 10 kDa. The killer toxin KT412 is probably not glycosylated since it did not show any detectable carbohydrate structures. KT412 was bound to sensitive but not to resistant yeast cells. The mannan, and not the glucan, fraction …
Muscle ultrasonography and computed tomography in elderly trained and untrained women
1993
Ultrasonography (US) and computed tomography (CT) were compared in studying the associations between long-term physical training and quadriceps muscle mass and structure in female athletes and controls, aged 66-85 years. Muscle cross-sectional area (CSA) measured using US correlated highly with that measured using CT, but the latter technique yielded 30% higher values on average. The echo intensity of the fasciae and bone measured by US correlated positively with the mean radiological density and negatively with the relative proportion of fat obtained from CT. Low intramuscular echo intensity was accompanied by high muscle density and low relative proportion of fat. The athletes had larger …
Immobilization of Hexacyanoferrate (III) for a Flow Injection-Spectrophotometric Determination of Promazine
1993
Abstract An automated flow injection method for the determination of promazine is described. The method is based on the oxidation of promazine by hexacyanoferrate (III) and spectrophotometric monitorization of oxidized drug. The chemical and FIA variables were optimized. The calibration graph was linear over the concentration range 2,5–25 ppm of promazine hydrochloride. Some interfering substances were also investigated. The method was applied for the determination of promazine in pharmaceutical formulations.
Moiré with zone plates pseudo-randomly encoded
1993
Abstract Moire patterns are a convenient method for optically sensing lateral displacements, or in-plane rotations. Sharp moire fringes are here created by using two zone plates, pseudo-randomly encoded. Our results may be useful in metrology, optical testing, and robotics. Experimental results are reported.
Sudden death due to cardiac sarcoidosis in a case of suspected homicide
1993
In a case of suspected homicide death due to natural causes — cardiac death (SCD) — was found at autopsy. Despite an extensive replacement of myocardial tissue by sarcoid granulomata there was no history of cardiac dysfunction or preceding symptoms. The transmurally infiltrating granulomata and the concomitant fibrosis were predominantly confluent. They occupied vast areas within the interventricular septum and the adjacent posterior wall of the left ventricle. The only other organs involved were mediastinal lymph nodes, which appeared macroscopically normal.
Pathogenesis of HSV-1/2 induced vaginitis/vulvitis of the mouse: dependence of lesions on genetic properties of the virus and analysis of pathohistol…
1993
A scoring system for herpes simplex virus (HSV) induced vaginitis/vulvitis in Balb/c mice was delineated from vaginal infections. Four degrees of vaginitis/vulvitis could be distinguished after infection with suitable strains of HSV despite nearly identical replication rates. The time course of replication, inflammation and pathohistology was compared further. Grade 0 was defined by lack of symptoms despite presence of strong replication, which was detectable at days 3-6. Focal necrotic lesions of the epithelial layer were present containing HSV-specific antigens. DNA could be detected by hybridization only in the outer zone of these areas. At day 6 these zones began to be re-epithelialized…
Many-body approach to low-energy pion-nucleus scattering
1993
Abstract We have extrapolated for low-energy pions ( T π = 0–50 MeV) the results for the pion-nucleus optical potential previously developed for pionic atoms. The evaluation is done using microscopic many-body techniques which allow us to separate the different contributions to the imaginary part of the potential and relate them to the different reaction channels: quasielastic and absorption. Elastic differential, reaction, absorption and quasielastic cross sections are evaluated for different nuclei and energies and contrasted with experiments. The agreement with data for the different channels, energies and nuclei is rather good with some isolated discrepancies.
First results from MAMI
1993
Abstract The 100% duty factor electron accelerator MAMI (Mainzer Mikrotron) has gone into operation. First experiments with quasi-monochromatic real photons have been performed. First results, mostly preliminary, are presented.
The effect of time, concentration and temperature on bioaccumulation in the gill of crayfish procambarus clarkii induced by organochlorine pesticides…
1993
Abstract 1. Crayfish were exposed to 1 25 th 96-hr lc 50 and 96-hr lc 50 of lindane and endosulfan for 1, 24, 48, 72 and 96 hr. 2. Concentrations of lindane and endosulfan were determined in gill tissue at 22°C and 29°C. 3. Clear differences were found in all concentrations, times and temperatures tested in gill tissues. 4. The highest accumulation of pesticide was found in the lc 50 endosulfan value.
Determination of the technetium-99m mercaptoacetyltriglycine plasma clearance in children by means of a single blood sample: a multicentre study
1993
A multicentre European study was undertaken in order to determine a reasonable algorithm allowing the determination of overall technetium-99m mercaptoacetyltriglycine clearance using a single blood sample. Employing multiple blood sample clearance as a reference method, it was shown that an acceptable estimation of the MAG3 renal clearance could be obtained using a blood sample taken at any time between 30 and 40 min after tracer injection. After correction for body surface area, comparison of clearance determined using (a) the single blood sample and (b) the multiple blood samples provided a coefficient of correlation of 0.949 and an SEE of 27 ml/min. This algorithm is valid for clearance …
A new method for the evaluation of anaerobic running power in athletes.
1993
A new maximal anaerobic running power (MARP) test was developed. It consisted of n.20-s runs on a treadmill with a 100-s recovery between the runs. During the first run the treadmill speed was 3.97 m.s-1 and the gradient 5 degrees. The speed of the treadmill was increased by 0.35 m.s-1 for each consecutive run until exhaustion. The height of counter-movement jumps and blood lactate concentration ([la-]b) were measured after each run. Submaximal ([la-]b = 3 mmol.l-1 and 10 mmol.l-1) and maximal speed and power (W3mmol, W10mmol and Wmax, respectively) were calculated and W was expressed in oxygen equivalents according to the American College of Sports Medicine equation. Thirteen male athletes…
Charmed pair correlations in π−Cu interactions at 230 GeV/c
1993
Abstract In the CERN NA32 experiment a high-resolution silicon vertex detector and a purely topological approach were used to collect 557 events consistent with associated charm production, both decay vertices being observed. The pseudorapidity gap distribution appears to be nearly independent of the nature of the charmed hadrons. This distribution is reasonably consistent with the next-to-leading order QCD calculations. However the azimuthal-angle distribution is significantly broader than the above predictions.
Direct determination of benzene in gasoline by flow-injection Fourier transform infrared spectrometry
1993
Abstract A Fourier transform infrared spectrometric procedure for the automated determination of benzene in gasoline was developed, based on the use of flow-injection analysis. The method permits the direct determination of benzene without any pretreatment of samples, with a limit of detection of 0.02% (v/v) and a relative standard deviation of ca. 1% [for five independent analyses of a diluted sample containing a 0.4% (v/v) of benzene]. Results found by direct analysis agreed with those obtained by off-line and on-line standard addition methods. A rapid quality control procedure was developed, based on the on-line injection of gasoline samples (diluted 1 + 9 in hexane) into a carrier strea…
Response to dopamine agonists of the rat isolated uterus.
1993
1. Quinpirole did not produce any effect in isolated uterus from oestrogenized rats even when it is contracted by KCl (37 mM). 2. Fenoldopam produced a relaxant effect on rat isolated uterus contracted by KCl which was not significantly modified by SCH 23390. 3. Reserpine decreased the effect of the lowest doses of fenoldopam. In reserpinized rats, propranolol (10(-9), 10(-8), 10(-7) M) antagonized the effect of the lowest doses of fenoldopam and neither SCH 23390, sulpiride nor ranitidine modified the effect of fenoldopam. 4. The results confirm our previous finding that DA1-receptors are not functional in our preparation. The effect of fenoldopam was partially due to a catecholamine-relea…