Structural organic chemistry in ecotoxicology

1993

Abstract Role of the methods of structural chemistry in assessment of the ecotoxic effects of organic compounds is described as examples of fate modeling based on structural properties, screening analyses of the affected population, use of model substances and various structure-specific determination methods. Case examples from literature are given and, in addition, structure screening and verification for a contaminant in herring is described.

Effect of nonequilibrium charge screening in A + B ? 0 bimolecular reactions in condensed matter

1993

The formalism of many-particle densities developed earlier by the present authors is applied to the study of the cooperative effects in the kinetics of bimolecular A +B--*0 reactions between oppositely charged particles (reactants). It is shown that unlike the Debye-Hiickel theory in statistical physics, here charge screening has essentially a nonequilibrium character. For the asymmetric mobility of reactants (DA=0, D~4:0) the joint spatial distribution of similar immobile reactants A reveals at short distances a singular character associated with their aggregation. The relevant reaction rate does not approach a steady state (as it does in the symmetric case, DA=DB), but increases infinitel…

Androgen metabolism in the skin of the rainbow trout (Oncorhynchus mykiss)

1993

Pieces of skin of male and female rainbow trout (Oncorhynchus mykiss) were incubated with testosterone and 11-ketotestosterone as substrates. In immature fish the conversion rate was low. In non-spawning adult males 11-ketotestosterone was reduced to 5α-11KDHT (up to 5.2%). In the fish in spawning condition the 5α-reduction rate was only about 1 to 2%. In the same specimens incubated with testosterone a high 11β-hydroxylase activity (23.8-25% in the male and 13% in the female skin) was found. Similar sex specific differences were observed for the occurence of 5α-reduced metabolites (about 20% in the male and 13% in the female tissue).

Comparative diazinon toxicity in guppy and zebra fish: Different role of oxidative metabolism

1993

Guppies pretreated with 1.1 μmol/L diazinon (0.5 times the LC50 with the guppy) for 7 d were less susceptible to the toxicity of the compound. The LC50 in these fish was about five times higher than that in nonpretreated animals. The lethal body burden and the slope of the concentration-response curve of diazinon in pretreated guppies were similar to those in zebra fish. The 7-d pretreatment of zebra fish with 12 μmol/L diazinon (0.5 times the LC50 with the zebra fish) did not affect the susceptibility of this species to diazinon. The pretreatment of guppies resulted in a strong inhibition of the formation of diazoxon and pyrimidinol during incubations of diazinon with the hepatic postmitoc…

Synthesis and NMR configurational study of imidazo[2,1-b]thiazoles from 1H-1,4-diazepine-7(6H)-thiones

1993

Abstract A thermal intramolecular cyclization of 1-vinyl2,3-dihydro-3 H -imidazole-2-thiones to imidazo[2,1-b]thiazoles is reported. A heteronuclear correlation study of these systems was made in order to establish the configuration of the products.

A common precursor for glia and neurons in the embryonic CNS of Drosophila gives rise to segment-specific lineage variants

1993

ABSTRACT The nervous system consists of two classes of cells, neurons and glia, which differ in morphology and function. They derive from precursors located in the neurogenic region of the ectoderm. In this study, we present the complete embryonic lineage of a neuroectodermal precursor in Drosophila that gives rise to neurons as well as glia in the abdominal CNS. This lineage is conserved among different Drosophila species. We show that neuronal and glial cell types in this clone derive from one segregating precursor, previously described as NB1-1. Thus, in addition to neuroblasts and glioblasts, there exists a third class of CNS precursors in Drosophila, which we call neuroglioblasts. We f…

Flow cytometric analysis of concanavalin A binding to isolated Golgi fractions from rat liver.

1993

Flow cytometry (FCM) has been used repeatedly to study lectin binding to whole cells. However, there are very few attempts to analyze glycoconjugates in isolated subcellular organelles. We have applied FCM to quantitate the specific binding of fluorescein-conjugated concanavalin A (FITC-Con A) to isolated cis and trans fractions of rat liver Golgi complex, the cell compartment involved in glycoprotein maturation and sorting. Our results show similar intensities of Con A-specific binding in the two fractions. Using this method we show a decreased FITC-Con A binding to both Golgi fractions in ethanol-treated rats, which is consistent to previous work on alcoholic effects on galactosyltransfer…

Abstracts of papers and posters safe handling of medicines

1993

A chemotaxonomic survey of Sonchus subgenus Sonchus

1993

Abstract Five species of Sonchus subgenus Sonchus were surveyed for their phenolic constituents. Seven flavonoids were identified: luteolin, luteolin-7-glucoside, apigenin, apigenin-3-glucoside, quercetin, quercetin-3-glucoside and quercetin-3-galactoside; three were phenolic acids; caffeic, chlorogenic and isochlorogenic; and two were coumarins: aesculetin and cichoriin. Their systematic significance for this genus is discussed.

Estimation of the environmental hazard of organochlorines in pulp mill biosludge used as soil fertilizer

1993

Abstract Contents of total organic chlorine and polychlorinated phenols, guaiacols, catechols, benzenes, cymenes, cymenenes, naphthalenes, toxic dibenzodioxins, toxic dibenzofurans, toxic PCB congener 77, alkylated dibenzofurans, alkylated bibenzyls and alkylated phenanthrenes in spent biosludges from activated sludge treatment plants of chlorobleaching kraft pulp mills are reported. Some estimations of hazard caused by these organochlorines to humans and wildlife from the use of biosludge as soil fertilizer are constructed and discussed.

Coherent and incoherent (μ−, e−) conversion in nuclei

1993

Coherent and incoherent (μ−, e−) conversion in nuclei is studied within the framework of several theories which violate flavour lepton number. A useful approach is followed which allows a factorization of the conversion widths into nuclear factors and other factors which depend only on the elementary process. The nuclear factors are evaluated in a wide range of nuclei allowing simple calculations of the conversion rates throughout the periodic table for a given theory with a minimum of work in the elementary sector. The coherent conversion is found to dominate the process. The results obtained modify appreciable previous results in the literature, particularly in the incoherent process.

Adrenergic Stimulation of Cyclic GMP Formation Requires NO-Dependent Activation of Cytosolic Guanylate Cyclase in Rat Pinealocytes

1993

Cyclic GMP (cGMP) formation in rat pinealocytes is regulated through a synergistic dual receptor mechanism involving beta- and alpha 1-adrenergic receptors. The effects of NG-monomethyl-L-arginine (NMMA), which inhibits nitric oxide (NO) synthase and NO-mediated activation of cytosolic guanylate cyclase, and methylene blue (MB), which inhibits cytosolic guanylate cyclase, were investigated in an attempt to understand the role of NO in adrenergic cGMP formation. Both NMMA and MB inhibited beta-adrenergic stimulation of cGMP formation as well as alpha 1-adrenergic potentiation of beta-adrenergic stimulation of cGMP formation, whereas they had no effect in unstimulated pinealocytes. The inhibi…

Fatty replacement of bone marrow after radiation therapy for Hodgkin disease: Quantification with chemical shift imaging

1993

The authors studied the long-term fatty replacement of bone marrow in 23 patients who had received radiation therapy for Hodgkin disease, with T1-weighted magnetic resonance imaging and quantitative chemical shift imaging. T1-weighted images revealed a mostly homogeneous high-signal-intensity pattern, in contrast to the hypointense pattern of nonirradiated marrow. The degree of fatty replacement was objectively assessed with chemical shift imaging, comparing patients to age-matched healthy volunteers. The authors found an increase in relative fat signal of 37% in the thoracic spine and 34% in the lumbar spine. The relative fat signal of nonirradiated pelvic and femoral marrow was decreased …

Synthesis of orthometallated rhodium(III) compounds. Crystal structures of [RhCl2{η2(C6H4)PPh2}(η2-dppm)] and [RhCl{η2(C6H4)PPh2}(η1-PCCl)(phen)] (…

1993

Abstract Neutral and cationic rhodium(III) metallated compounds containing a four-membered ring are prepared by different synthetic methods: (i) from rhodium(I) compounds that contain the ligand P( o -ClC 6 H 4 )PPh 2 , by 2c-2e intramolecular oxidative addition; (ii) from metallated dirhodium(II) compounds; (iii) by ligand substitution in [RhCl 2 {η 2 -(C 6 H 4 )PPh 2 }{η 2 -P( o -ClC 6 H 4 )Ph 2 }]. The crystal structures of [RhCl 2 {η 2 -(C 6 H 4 )PPh 2 }(η 2 -dppm)] ( 2 ) and of the dichloromethane solvate of [RhCl{η 2 -(C 6 H 4 )PPh 2 }{η 1 -P( o -ClC 6 H 4 )Ph 2 }(phen)](SbF 6 ) ( 11 ) have been determined by X-ray diffraction methods. In both complexes the Rh atom is in the distorted…

Hausdorff measures, Hölder continuous maps and self-similar fractals

1993

Let f: A → ℝn be Hölder continuous with exponent α, 0 < α ≼ 1, where A ⊂ ℝm has finite m-dimensional Lebesgue measure. Then, as is easy to see and well-known, the s-dimensional Hausdorif measure HS(fA) is finite for s = m/α. Many fractal-type sets fA also have positive Hs measure. This is so for example if m = 1 and f is a natural parametrization of the Koch snow flake curve in ℝ2. Then s = log 4/log 3 and α = log 3/log 4. In this paper we study the question of what s-dimensional sets in can intersect some image fA in a set of positive Hs measure where A ⊂ ℝm and f: A → ℝn is (m/s)-Hölder continuous. In Theorem 3·3 we give a general density result for such Holder surfacesfA which implies…

Some linear and branched macromolecules by ring-opening polymerization

1993

In the first part the ring-opening polymerization of some macrocyclic ether-acetals is briefly described. Of special interest are acetal polymers with functional groups, for instance C=C-double bonds. Appropriate unsaturated monomers and their polymerizability are discussed. The second part deals with the polymerization of oxazolines, substituted in 2- and/or 4-position. Branched polymers are obtained by copolymerization of 2-ethyl-2-oxazoline with 2-hexyl-2-oxazoline or 2-undecyl-2-oxazoline. The properties of the random copolymers and corresponding block copolymers are compared. By a “mixed mechanism technique” a block copolymer composed of a poly(tert -butyl methacrylate) block and a pol…

Comparison of Volatile Flavor Compounds Produced by Ten Strains of Penicillium camemberti Thom

1993

Abstract Volatile compounds produced by Penicillium camemberti Thom in a milk culture medium were identified using gas chromatography coupled with mass spectrometry. Volatile compounds were mainly methyl ketones and their corresponding secondary alcohols, fatty acids, and the alcohols 3-methylbutanol, 2-methylpropanol, 3-octanol, and 1-octen-3-ol. Comparison of 10 strains of P. camemberti Thom resulted in their being grouped into 6 aromatic strain groups, This grouping seems to be useful for the selection of strains for cheese making.

A Note on the algebraic approach to the «almost» mean-field Heisenberg model

1993

We generalize to an «almost» mean-field Heisenberg model the algebraic approach already formulated for Ising models. We show that there exists a family of «relevant» states on which the algebraic dynamics αt can be defined. © 1993 Società Italiana di Fisica.

Interannual variability of rainfall in the eastern horn of Africa and indicators of atmospheric circulation

1993

Relationships between rainfall variations in the Eastern Horn of Africa, the Southern Oscillation, and the Indian Ocean temperature and pressure surface fields are studied for the period 1932–83. Rainfall data consist of stations and regional indices calculated for three selected areas experiencing quite different rainfall patterns. The results indicate significant negative correlations between northern autumn rains in Somalia and the Southern Oscillation during the same season. These rains are also negatively correlated with pressure in the Western Indian Ocean, and positively correlated in the Eastern Indian Ocean. The reverse pattern is shown with sea-surface temperature. This agrees ver…

Applications of mathematical modelling to the simulation of binary perfusion chromatography

1993

Abstract A mathematical model of binary (competitive adsorption involving two components) perfusion chromatography is used to simulate and study the behavior of a binary adsorption system. The dynamic behavior of column systems (frontal analysis) is examined for different particles sizes, column fluid superficial velocities, Vf, and intraparticle fluid velocities, νp. Column systems with perfusive (νp > 0) and purely diffusive (νp = 0) adsorbent particles are studied. The results obtained from the binary system studied in this work suggest that the times at which breakthrough begins for components 1 and 2, and the dynamic (unsteady state) relative separation between components 1 and 2 obtai…

Écoles de base : les raisons du succés

1993

International audience

Die fiberoptische Intubation neurochirurgischer Patienten*

1993

Patients with cervical spine injury presenting with respiratory distress require airway management that does not compromise integrity of the atlanto-occipital joint. Endotracheal intubation by means of direct laryngoscopy is not suitable. The method of choice is nasotracheal intubation of the awake patient, using a flexible fibre bronchoscope. If anatomy or surgical access render the nasal approach impossible, fibre optic intubation can be performed orotracheally, utilising specific technical aids. Flexible fibrescopes are available in different sizes (length and diameter): selection is base on the patient's anatomical requirements. Aids to orotracheal intubation are constructed with a bore…

Distribution of sulphur forms in soils from beech and spruce forests of Mont Loz�re (France)

1993

From a quantitative inventory of sulphur forms and sulphur budget, the relation between the distribution of the various sulphur forms and the sulphate fluxes in three soil profiles has been addressed. These profiles are located in two forested watersheds at Mont Lozere. One has been sampled in a beech forest and the other two in a spruce forest and in a harvested plot of this spruce forest, respectively. The mean annual input-output budgets showed a sulphur immobilization in the soil cover of the three plots. In the preserved spruce forest plot, because of larger dry depositions, the sulphur immobilization is much greater than in other plots and occurs essentially in the B horizons. In the …

Electron Microscopy of Human Erythrocyte Catalase: New Two-Dimensional Crystal Forms

1993

Abstract Using the mica-spreading "negative staining-carbon film" procedure, human erythrocyte catalase has been shown to create a number of different periodic or crystalline two-dimensional (2-D) arrays which differ in the arrangement of molecules in the repeating units and the lattice type. Digital image processing has been performed with a 2-D array which contains regularly arranged "undulating" rows of molecules and also with a 2-D crystal form, exhibiting pgg (p22 1 2 1 ) symmetry and lattice parameters of a = 12.7 nm, b = 44 nm, and γ= 92°. The data are compared with our previous analysis of a different human erythrocyte catalase 2-D crystal, and the effect of partial-depth negative s…

Spiroterpenoids from Hypericum reflexum

1993

Abstract Two new spiroterpenoids, hyperireflexolide A and B, were isolated from Hypericum reflexum . Their structures and stereochemistry were established by spectroscopic methods, including 13 C NMR, DEPT and HMQC, and X-ray data.

Alternating Ferro- and Antiferromagnetic Interactions in a Chainlike CuII Coordination Polymer

1993

Theoretical study of Fe doping and oxidation–reduction influence on the photorefractive effect in BaTiO_3

1993

We numerically solve charge-transport and Poisson equations for photorefractive BaTiO3 single crystals with a band model, using four impurity levels, Fe2+–Fe3+, Fe3+–Fe4+, VO••–VO•, and VO•-VOx. Densities and photoinduced spatial distributions of each population are computed as a function of annealing O partial pressure. Space-charge field and beam-coupling gain are also computed as a function of annealing O partial pressure, temperature, Fe concentration, grating wave vector, and light intensity. We discuss the intervening mechanism of impurity centers and the correlations between experimental conditions of crystal growth, oxidation–reduction treatments, and measurement parameters.

Is preoperative radiographic localization of islet cell tumors in patients with insulinoma necessary?

1993

Preoperative localization tests [sonography, computed tomography, angiography, percutaneous transhepatic portal venous sampling for insulin radioimmunoassay (PTP)] have a sensitivity of 60% to 90% in cases of organic hyperinsulinism. In all publications, however, the sensitivity of intraoperative localization, 75% to 100%, is distinctly higher. With the exception of PTP, all tumors that can be identified by preoperative localization can also be detected using palpation or intraoperative sonography. Preoperative localization diagnosis is therefore not absolutely necessary prior to primary operation in the case of organic hyperinsulinism. It is requested by many surgeons because: (1) only a f…

Polypeptide Markers Differentiating Juvenile and Adult Tissues in Chestnut

1993

Differences were observed between the polypeptide contents of in vitro shoot cultures derived from upper branches (adult material) and basal shoots (juvenile material) of the same chestnut tree. Cultures derived from mature crown growth yielded two polypeptide bands that were not afforded by cultures derived from juvenile basal shoots. Since all cultures were derived from the same tree the polypeptide differences appear to reflect the ontogenetic age of the starting material.

Biological effects of short-chain fatty acids in nonruminant mammals.

1993

propionate, volatile fatty acids (VFAs), cholesterol, cell prolifera­ tion, human gastric lipase

(o-Hydroxyphenyl)methylphosphonic Acids: Spectrophotometric determination of their pKavalues and of the deprotonation sequence

1993

UV/VIS Absorption spectra of nitrosubsituted (o-hydroxyphenyl)methylphosphonic acids (o-(phosphonomethyl)phenols) were measured as a function of pH at 25° in 0.1M NaClo4 solutions. Computational treatment of the whole set of optical density data between 200 and 500 nm resulted in the determination of the dissociation constants of these polyacids and also of the individual electronic spectra of all the species involved in the deprotonation sequence. The spectral behavior gives information on the structure of the anions formed and consequently the order of the subsequent deprotonation steps could be deduced. For the (2-hydroxy-3-nitro(or 5-nitro)phenyl)methylphosphonic acid and the 2-hydroxy-…

Claustros de la Facultad de Medicina de Valencia entre 1683 y 1707

1993

The University of Valencia at the time when traditional local law prevaliled lacked the documentary riches that the Castilian universities offered to investigators. Essential among these materials are the minutes of the University professors which allow to gain a more dynamic view of the university phenomenon and a better understanding of academic life. Hitherto we had only known the agreements adopted by the full meeting of professors of the Valencia University, and none but indirect references were available from other essemblies held by the professors of the Faculty of Medicine and by the professors of the different faculties. The current articles proves their existence and produces the …

On the Physical Propagators of QED

1993

The true variables in QED are the transverse photon components and Dirac's physical electron, constructed out of the fermionic field and the longitudinal components of the photon. We calculate the propagators in terms of these variables to one loop and demonstrate their gauge invariance. The physical electron propagator is shown not to suffer from infrared divergences in any gauge. In general, all physical Green's functions are gauge invariant and infrared-finite.

Site specificity of pea histone acetyltransferase B in vitro.

1993

Histone acetyltransferase B from pea embryonic axes has been purified approximately 300-fold by a combination of chromatographic procedures, including affinity chromatography on histone-agarose. The enzyme preparation has been used for the in vitro transfer of acetyl groups from [1-14C]acetyl-CoA to non-acetylated pea histone H4. Up to three acetyl groups can be introduced into the histone. The resulting mono-, di-, and triacetylated H4 isoforms were separated and sequenced to determine the acetylated sites. Only sites 5, 12, and 16 were used by histone acetyltransferase B, but no clear preference among them was observed. The absence of modification of other potentially acetylatable sites i…

The primary structure of cytoplasmic initiator tRNAMetfromSchizosaccharomyces pombe

1993

Spherical random-field systems with long-range interactions: general results and application to the Coulomb glass

1993

A classical spherical random-field Hamiltonian with long-range (power-law) interactions is investigated by means of the replica theory. Both ferromagnetic and anti-ferromagnetic interactions are considered. The use of continuous variables instead of Ising variables in the spherical version of the model allows one to calculate the free energy exactly. The existence of an equilibrium phase transition is investigated based on the replica-symmetric solution. The results are applied to the Coulomb-glass model of interacting localized electrons in a disordered solid. This model is shown not to have an equilibrium phase transition for spatial dimensions D 4 the model has a phase transition to an o…