Uptake and storage of choline by rat brain: influence of dietary choline supplementation.

1991

In order to elucidate the regulation of the levels of free choline in the brain, we investigated the influence of chronic and acute choline administration on choline levels in blood, CSF, and brain of the rat and on net movements of choline into and out of the brain as calculated from the arteriovenous differences of choline across the brain. Dietary choline supplementation led to an increase in plasma choline levels of 50% and to an increase in the net release of choline from the brain as compared to a matched group of animals which were kept on a standard diet and exhibited identical arterial plasma levels. Moreover, the choline concentration in the CSF and brain tissue was doubled. In th…

Schizophrenia and automatic processing: an exploratory study.

1991

This study deals with the schizophrenic deficit as one of automatic processing. To test the idea, a special experimental task was designed on which 21 schizophrenics, 21 depressives, and 21 normal subjects had to complete a series of simple geometric figures. When the subjects had thoroughly learned this activity, another information source, a brief story, was introduced, and the subjects had to pay attention to the story while they did the task. Two dependent variables were considered, execution time and performance. There were no differences among the three groups in the first experimental condition; but in the second condition, when the distractor was introduced, schizophrenics needed m…

Ultrastructural Lesion in Autoimmune Hepatitis and Steps of the Immune Response in Liver Tissue

1991

Histological and electron microscopical observations on the effects of lead on gills and midgut gland ofProcambarus clarkii

1991

Adult intermolt specimen of Procambarus clarkii (Crustacea, Decapoda) have been treated for 96 hours in aquaria with 100mg/l of lead. The gills and midgut gland were processed and studied in the electron microscope. The gill filament shows important changes in the ultrastructure of the epithelial cells and the cuticle. The hepatopancreatic cells studied (i.e. the vacuolated and dark cells) do not show noticeable structural changes but accumulate lead (electrondense precipitates) mainly in lysosomes.

Substituent effect on oxidative cyclization of aldehyde thiosemicarbazones with ferric chloride

1991

The reactivity of aldehyde thiosemicarbazones 1 with ferric chloride solutions was examined. When compounds 1 are not substituted on the N-2 nitrogen atom formation of 1,3,4-thiadiazole 3 heterocyclic ring was observed. In contrast 1,2,4-triazoline 4 and/or 1,3,4-thiadiazoline 5 heterocyclic rings were afforded when N-2 nitrogen atom carried a methyl or a phenyl group. The reaction mechanism is also discussed.

Thermal studies of sulphonamide derivative complexes

1991

Abstract A thermal study of a new series of acetazolamidate complexes of Co(II), Ni(II) and Cu(II) using the TG, DTG and DTA techniques in flowing air, static air and N 2 atmospheres is described. From the TG-DTG and DTA curves, different thermal behaviours can be observed. Although in all the complexes the processes of dehydration, deammination and pyrolysis can be clearly observed, in some cases they appear as several well-separated steps and, in others, as continuous stages which take place simultaneously. The differences observed between the pyrolytic decomposition in flowing air and in nitrogen are described. In flowing air, metal sulphate is formed from the thiadiazole ring, except fo…

Synthesis and characterization of complexes of trialkyl- and triarylphosphine gold(I) with thiolated purines and pyrimidines. A class of bifunctional…

1991

Abstract New complexes of the type R 3 PAuL or (R 3 PAu) 2 (μ-L) where R=ethyl or phenyl and L=6-thioguanine, 2, 6- dithioxanthine, 2, 4-dithiouracil and/or dithioerythritol have been prepared. These complexes have been identified by using elemental analysis, 1 H, 13 C and 31 P NMR spectroscopy. The structures have been proposed based on these spectroscopic studies. Sulfur appears to be the binding site in disubstituted complexes of 2, 4-dithiouracil and 1, 4-dithioerythritol, while the phosphine gold( I ) moieties appear to be S and N bonded in 2, 6-dithioxanthine and 6-thioguanine. The potential use of these complexes as antitumor drugs is discussed.

<title>Multiphoton-absorption-induced structural changes in fused silica</title>

1991

The basic properties (light refractive index, density, mechanical strength, etc.) of fused silica are changed by the influence of high-intensity light from the glass transparency region capable of generating excitons by multiphoton absorption. The self-trapped exciton decay near the microcavity in the fused silica structure leads to the stable elementary intrinsic defect pair (nonbridging oxygen atom and three-fold-coordinated silicon atom) generation. At the large- enough light intensities near such a microcavity with a defect, the next exciton can be self- trapped. Then the next elementary defect can appear in the microcavity, and a chemical bond between it and the previously generated de…

Calorimetric investigation of the vulcanization of factice

1991

Sulphur factice is produced from a mixture of a vegetable oil and sulphur at temperatures between 130 and 160‡C. The slow exothermal vulcanization results in rubber-like elastomers. We have developed an isothermal calorimeter for measurements both in the liquid and the solid state and simulated the production process at the laboratory scale. The compensating calorimeter consists of a hot plate equipped with thin aluminium rods descending into a Dewar vessel. Besides optimization of the temperature control, remarkable savings of time were achieved by previous elaidinization of the oil using hydrosulphide.

Use of BICAP in a case of colon angiodysplasia

1991

This paper reports on a case of colonic bleeding from an angiodysplastic lesion of the ascending colon in a 71-year-old diabetic woman, resulting in severe anemia in the patient, who was treated using the BICAP electrocoagulation system. The present report includes a description of this technique, which involves the use of a 7-F hemostatic probe connected to a 25-W BICAP source.

Steatocrit test after a standard fatty meal: A new simple and sensitive test to detect malabsorption

1991

The steatocrit test, a simple semiquantitative method for determining fat content in stool, was performed after a standard fatty meal to detect malabsorption in patients with celiac disease. Thirty-seven children (mean age 2.6 +/- 2.1 years) with total atrophy of the intestinal villi and 79 controls (mean age 3.5 +/- 2.8 years) were studied. All subjects underwent a small-bowel biopsy, a D-xylose absorption test, a rapid triglyceride absorption test, and a steatocrit determination first on an uncontrolled diet and then again after a standard fatty meal. The steatocrit test after a fatty meal did not detect any false-positive or false-negative results, while the D-xylose test showed two fals…

Prediction of the carbon-13 NMR chemical shifts of polysubstituted benzenes with homogeneous substituents

1991

A new incremental scheme for the calculation of the 13C NMR chemical shifts in polysubstituted benzenes with homogeneous substituents was derived and applied to spectral prediction for C6XnH6−n where XCH3, C2H5, i-C3H7, CF3, F, Cl, Br, COOH. Owing to the use of only two-particle increments the procedure is simple enough to be carried out on hand calculators, and gives complete agreement with experimental values within a few tenths of a ppm in all cases compared (76 compounds). The 13C NMR chemical shift was predicted for hexaethylbenzene with a good fit to the experiment value, and also for 20 unmeasured compounds. The present scheme can be used as an algorithm in structure-searching progra…

Coherent and incoherent η-photoproduction from nuclei

1991

Abstract Elastic and inelastic η-photoproduction from complex nuclei is studied in a distorted-wave impulse approximation (DWIA) framework. The elementary operator is obtained by using a dynamical model which employs the reactions π N→ π N, π N→ ππ N and π − p→ η n to fix the hadronic vertex as well as the isobar propagators and the process γ N→ π N to constrain the electromagnetic vertex. The nuclear structure input for the inelastic transitions has been extracted from electron-scattering form factors. The η final-state interaction has been included via a simple optical potential using the ηN t -matrix as an input. We find that coherent η-production is dominated by the D 13 (1520) isobar w…

The baryonic spectrum of QCD 2 in the chiral limit

1991

Abstract A description of the baryonic spectrum of quantum chromodynamics in one-space-one-time dimensions for massless quarks is presented. The theory has been studied in the equivalent non-abelian bosonic representation, and four-point functions of the colored meson fields under the simplifying assumption of two colors have been calculated. The crucial role of the chiral sector in providing baryon number has been unveiled. Excited baryon states appear as pseudomesonic excitations on top of the massless baryons associated with the chiral fields.

Multiple incoherent 2D optical correlator

1991

Abstract A nonconventional setup, based on the Lau effect, is employed for implementing a lensless version of an incoherent object-space correlator of 2D signals with compact support. Experimental results are also shown.

Mean-field correlations in the core of rich galaxy clusters

1991

We develop a theory for the contribution to the clustering correlation function from gravitational interactions of neighboring pairs of galaxies in clusters. This is based on the «Hypernetted Chain Equation», a self-consistent integral equation relating the correlation function to the interaction potential.

Experimental Models of Autoimmune Hepatitis

1991

Effects of 3,4-dichloroaniline on fish populations. Comparison between r- and K-strategists: A complete life cycle test with the guppy (Poecilia reti…

1991

In order to compare data derived from life cycle tests with zebrafish (Brachydanio rerio Ham.- Buch.), an r-strategist, with data of fish exhibiting a differing strategy of reproduction, a complete life cycle test with the guppy (Poecilia reticulata Peters) was performed with the chemical 3,4-dichloroaniline. The generation of guppies exposed during the whole life span (FI) reacted with more sensitivity than the generation exposed only as adults (Fo): Growth of adult females and reproduction was reduced significantly at 200 Μg/L in Fo, and even at 2 and 20 Μg/L in FI. The survival rates of the early life stages were not influenced at the tested concentrations. There is hardly any difference…

Korn, Andreas: Weltwirtschaft und internationale Verschuldung: Eine Analyse von Ursachen, Auswirkungen und L�sungsans�tzen der internationalen Schuld…

1991

Subcutaneous gonadotropin therapy in male patients with hypogonadotropic hypogonadism

1991

Objective The response to subcutaneous (SC) gonadotropin replacement therapy, using human chorionic gonadotropin (hCG) and human menopausal gonadotropin (hMG) or hCG alone, was evaluated in male hypothalamic hypogonadism. Design Sixteen patients with hypothalamic hypogonadism were treated with gonadotropins for induction of puberty and normalization of spermatogenesis. The results were analyzed retrospectively. Setting The study was carried out in a clinical endocrinology department providing tertiary care and in private practices of endocrinology. Patients Eight patients with idiopathic hypogonadotropic hypogonadism and eight patients with Kallmann's syndrome in prepubertal or early pubert…

Oligoethyleneoxide spacer groups in polymerizable surfactants

1991

Cationic and zwitterionic polymerizable surfactants bearing tri- and tetraethyleneglycol spacer groups between the polymerizable moiety and the surfactant structure were prepared and polymerized. Monomers and polymers were investigated with respect to their aggregation behavior in aqueous systems and compared to analogous monomers and polymers lacking spacer groups. In the case of the monomeric surfactants, the spacer groups depress both the Kraffttemperature and the critical micelle concentration. the area occupied per molecule at the air-water interface is substantially enlarged by the spacers, whereas the depression of surface tension is nearly constant. Although the monomers with and wi…

Retinyl ester hydrolases in retinal pigment epithelium.

1991

In bovine retinal pigment epithelium membranes we have found three hydrolases which were active against trans-retinyl palmitate. This was possible by assaying different subcellular fractions as a function of pH in the range 3-9. Detection of these activities has been favored by the use in the enzyme assay of Triton X-100, which has an activating effect up to a concentration of 0.03% at a detergent-protein ratio of about 1.5-3.0. Apparent kinetic parameters for the retinyl ester hydrolases have been determined after a study of the optimization of assay conditions. Vmax values for hydrolases acting at pH 4.5, 6.0, and 7.0 were, respectively, 156, 55, and 70 nmol/h/mg. To identify the subcellu…

Preoperative detection of intrathoracic tumor spread of esophageal cancer: endosonography versus computed tomography.

1991

The results of endosonography and computed tomography, using an optimized CT technique, have been compared in the preoperative detection of intrathoracic tumor spread of esophageal cancer. In 22/40 patients with esophageal tumors complete passage of the ultrasonic endoscope was possible. Endosonography was superior to CT in the assessment of early stage of esophageal tumor (T1-2). Out of 9 tumors confined to the esophageal wall, 8 were classified correctly by endosonography and only 5 by computed tomography. The results in advanced T3 and T4 tumors (13 patients) were comparable following endosonography and computed tomography. Endosonography is an important means of selecting patients with …

Commutativity conditions on rings

1991

We prove the following result: let R be an arbitrary ring with centre Z such that for every x, y ∈ R, there exists a positive integer n = n(x, y) ≥ 1 such that (xy)n − ynxn ∈ Z and (yx)n − xnyn ∈ Z; then, if R has no non-zero nil ideals, R is commutative. We also prove a result on commutativity of general rings: if R is r!-torsion free and for all x, y ∈ R, [xr, ys] = 0 for fixed integers r ≥ s ≥ 1, then R is commutative. As a corollary we obtain that if R is (n + 1)!-torsion free and there exists a fixed n ≥ 1 such that (xy)n − ynxn = (yx)n − xnyn ∈ Z for all x, y ∈ R, then R is commutative.

The decay η → π0h0 in two-higgs-doublet models

1991

The possibility of a light scalar in the framework of two-Higgs-doublet models is studied. The range of masses 100 MeV < mh0 < 2mπ is already excluded by present experiment bounds on the transition η → π0h0 in the model where the neutral component of one doublet couples to fermions with weak isospin T3 = −12 and the neutral component of the second doublet to fermions with T3 = +12. These bounds also constrain tightly the structure of the Yukawa couplings in two-Higgs-doublet models.

Mainz/PSI Φ-factory design considerations

1991

Abstract Design considerations for a Φ-factory with a Luminosity of the order of 10 33 cm −2 s −1 lead to the concept of a multi-bunch round beam double storage ring with supercoducting solenoids for micro-beta focusing and beam rotation. Simulations of the beam-beam-interaction indicate, that significantly higher beam-beam-parameters may become possible with round beams. A rough draft design of a round beam Φ-factory is presented.

Hepatitis B defective virus with rearrangements in the preS gene during chronic HBV infection.

1991

We have found a defective form of HBV2 in a HBsAg- and anti-HBe-positive patient with liver cancer. Viral deletions were identified in the preS coding region using PCR. The presence of deleted HBV forms was observed in serum, PBMC, and liver samples. After sequencing 12 clones were analyzed (subtype adr). In 9 out of 12 clones a 183-bp in-frame deletion was recorded in the preS1 region (2995 to 3177). Three out of 9 clones also yielded rearrangements of the preS2 N-terminal part. Four out of 9 showed numerous point mutations in the preS1 and preS2 sequence. In addition, 3 out of 12 clones, which did not show the 183-bp preS1 deletion were found to have small deletions and insertions in the …

Analysis of Hemolymph Ecdysteroids in the Female Earwig: Labidura riparia

1991

International audience; The nature of hemolymph ecdysteroids was analyzed by high performance liquid chromatography-radioimmunoassay, during the two main phases of the reproductive cycles of Labidura riparia. 20-hydroxyecdysone and ecdysone were present together with polar and apoiar products.Changes in the ecdysone/20-hydroxyecdysone ratio were evidenced according to the ovarian development. During natural (feeding and sexual phase of the cycle) or induced ovarian development, an increase of the ratio occurred whereas, during ovarian rest (fasting and/or parental phase), a significant decrease was observed.Up to 40 days after ovariectomy, immunoreactive compounds were observed in the hemol…

Higher-order polarizations on the Virasoro group and anomalies

1991

In a previous paper the authors showed that the space of (first order) polarized functions on the Virasoro group is not, in general, irreducible. The full reduction was explicitly achieved by taking the orbit of the enveloping algebra through the vacuum. This additional step provided the proper quantization in the “strong-coupling” domain 0<c≦1. In this paper we introduce the concept of “higher order polarization” as a generalization of that of polarization. We prove that the imposing of the additional (higher-order) polarization conditions is equivalent to the taking of the above-mentioned orbit. This demonstrates that the generalized (higher-order) polarization conditions suffice to obtai…

Repetitive nucleotide sequencing of a dispensable DNA segment in a clonal population of African swine fever virus

1991

Abstract Repetitive nucleotide sequencing of a dispensable genomic segment of a clonal population of African swine fever (ASF) virus has been carried out to estimate the mutant frequency to neutral alleles. Since no mutations have been detected in a total of 54026 nucleotides screened, the maximum mutant frequency is 5.5 × 10 −5 substitutions/nucleotide (95% confidence level). The result renders very unlikely the occurrence of hypermutational events during ASF virus DNA replication, at least within the selected DNA fragment.

Thermal fluctuation effects in ferroelectric liquid-crystal polarization reversal: Light scattering from a transient domain-wall foam

1991

Thermal orientation fluctuations of the director field during electric-field-induced polarization reversal in ferroelectric liquid crystals lead to the nondeterministic formation of a transient domain-wall foam that strongly scatters light. This foam comprises domains of molecules that have reoriented locally in the same sense on the smectic-C tilt cone and are separated from one another by 2\ensuremath{\pi} inversion walls. The dynamics of formation and the subsequent annealing of the foam have been probed using laser light scattering. Anisotropic coarsening of the foam, which is accounted for by including electrostatic (space-charge) interactions in the theoretical description of the ferr…

Immunohistochemical evaluation of growth fractions in human breast cancers using monoclonal antibody Ki-67.

1991

We performed immunohistochemical analyses of 568 breast/cancer specimens using Ki-67, a monoclonal antibody specific for a nuclear antigen present in proliferating cells. The specimens were divided into three groups (I-III) according to the proportion of Ki-positive cells detected. These findings were compared with features of tumor extension as well as with certain prognostic variables. There was no detectable correlation between Ki-67 reactivity and either tumor size or node involvement. In contrast, a statistically significant correlation was found between Ki-67 reactivity and tumor grading, in that G-I tumors had small growth fractions, while a high proportion of G-III tumors exhibited …

Isolation of chlorinated dibenzothiophenes by high-performance thin-layer chromatography

1991

Abstract Chlorinated dibenzothiophenes can cause environmental problems analogous to chlorinated dibenzodioxins and dibenzofurans. In the analysis of chlorinated dibenzodioxins by gas chromatography—mass spectrometry some unknown chlorinated compounds have been found. The chlorinated dibenzothiophenes have the same m/z values as the corresponding dioxins in low-resolution mass spectrometry and they are found in same planar aromatic compound fraction in alumina and carbon column chromatography. Some chlorinated dibenzothiophenes were synthesized to serve as model compounds in analytical work. High-performance thin-layer chromatography (TLC) with different plates and several eluents was tried…

Self-learning inductive inference machines

1991

Self-knowledge is a concept that is present in several philosophies. In this article, we consider the issue of whether or not a learning algorithm can in some sense possess self-knowledge. The question is answered affirmatively. Self-learning inductive inference algorithms are taken to be those that learn programs for their own algorithms, in addition to other functions. La connaissance de soi est un concept qui se retrouve dans plusieurs philosophies. Dans cet article, les auteurs s'interrogent a savoir si un algorithme d' apprentissage peut dans une certaine mesure posseder la connaissance de soi. lis apportent une reponse positive a cette question. Les algorithmes d'inference inductive a…

Determination of triazines and organophosphorus pesticides in water samples using solid-phase extraction.

1991

Abstract Octadecyl (C 18 )-bonded porous silica was evaluated for the extraction of triazine and organophosphorus pesticides from natural water. The extraction results showed an effective performance when 1 l of water was passed through small glass columns containing 500 mg of 50–100-μm C 18 bonded porous silica. The absorbed compounds were removed with ethyl acetate, evaporated to 200 μl and determined by gas chromatography. The overall average recoveries were greater than 85% except for dimethoate and trichlorfon. Application of this procedure to the analysis of natural water samples gave results that agree well with those obtained by solvent extraction methods.

Non-commutative geometry and supersymmetry II

1991

Abstract Extending results of a previous work [Phys. Lett. B 260 (1991) 359], we establis that anothe non-commutative model proposed by Balakrishna, Gursey and Wali may be expressed as a Yang-Mills theory of a graded Lie group.