Titanocene(III) catalyzed homogeneous hydrosilation-hydrogenation of pyridines

2001 ◽  
Vol 79 (5-6) ◽  
pp. 1075-1085 ◽  
Author(s):  
John F Harrod ◽  
Ronghua Shu ◽  
Hee-Gweon Woo ◽  
Edmond Samuel
Keyword(s):  
Complete Saturation

The homogeneous catalytic hydrosilation-hydrogenation of pyridines is observed in the presence of Cp2TiMe2 (Cp = η5-C5H5) and CpCp*TiMe2 (Cp* = η5-C5Me5) as catalysts and using PhSiH3 or PhMeSiH2 as the source of Si-H. Under appropriate conditions, and with appropriate ring-substitution, good yields of the N-silyl-dihydropyridine or N-silyltetrahydropyridine products are be obtained. Although complete saturation is not achieved with organosilane alone, carrying out the reaction under moderate H2 pressures can give excellent yields of N-silylpiperidines. Under moderate pressures of H2, [Cp2TiH]2 catalyzes rapid H-D exchange between H2 and the 2- and 6-positions of C5D5N. Under the same conditions, only traces of hydrogenation are observed. This, together with the regioselectivity of 3-picoline hydrosilation-hydrogenation, leads to the conclusion that the key step in the reaction is probably addition of Ti-Si to C=N.Key words: hydrosilation, hydrogenation, pyridines, dimethyltitanocene, catalysis.

A New Method for Plasminogen Standardization

1968 ◽  
Vol 20 (03/04) ◽  
pp. 548-554
Author(s):  
J Gajewski ◽  
G Markus
Keyword(s):  
Proteolytic Activity ◽  
Specific Activity ◽  
Molar Ratio ◽  
Sharp Transition ◽  
Equivalence Point ◽  
Constant Amount ◽  
Residual Level ◽  
Activity Measurements ◽  
Complete Saturation ◽  
Human Plasminogen

SummaryA method for the standardization of human plasminogen is proposed, based on the stoichiometric interaction between plasminogen and streptokinase, resulting in inhibition of proteolytic activity. Activation of a constant amount of plasminogen with increasing amounts of streptokinase yields linearly decreasing activities, as a function of streptokinase, with a sharp transition to a constant residual level. The point of transition corresponds to complete saturation of plasmin with streptokinase in a 1:1 molar ratio, and is therefore a measure of the amount of plasminogen present initially, in terms of streptokinase equivalents. The equivalence point is independent of the kind of protein substrate used, buffer, pH, length of digestion and, within limits, temperature. The method, therefore, is not subject to the variations commonly encountered in the usual determination based on specific activity measurements.

Responses to Hypersaline Exposure in the Euryhaline Crayfish PAcifastacus Leniusculus: II. Modulation of Haemocyanin Oxygen Binding In Vitro and In Vivo

1982 ◽  
Vol 99 (1) ◽  
pp. 447-467
Author(s):  
MICHÈLE G. WHEATLY ◽  
B. R. MCMAHON
Keyword(s):  
Salt Effect ◽  
Ionic Composition ◽  
Inorganic Ions ◽  
Pacifastacus Leniusculus ◽  
Oxygen Binding ◽  
Complete Saturation ◽  
O2 Delivery ◽  
O2 Binding

The effect of 48 h of hypersaline exposure (25, 50 and 75% SW) on haemocyanin oxygenation properties in the euryhaline crayfish Pacifastacus leniusculus was investigated in vitro and in vivo. In vitro significant increases in affinity and cooperativity were measured, although the magnitude of the Bohr shift was unaffected. In vitro dialysis of haemolymph against physiological salines of variable ionic composition proved that these changes were only partly attributable to altered levels of haemolymph ions, implicating the existence of modulators other than H+ and inorganic ions, the possible identities of which are discussed. Significant depressions of both pre- and postbranchial oxygen tensions (Pv, Ov, O2 and Pa, Oa, O2) were observed, but O2 delivery was maintained by utilization of the venous reserve and by an increase in haemocyanin O2 affinity. This occurred despite a concomitant acidosis whose effect on O2 affinity was directly opposed by the ‘salt’ effect. Under hypersaline conditions, haemocyanin played an increasingly important role in O2 delivery in vivo. Despite a reduction in the concentration of combined O2 at complete saturation of the pigment (CmaxHCyOHCyO2). indicating lowered haemocyanin concentration, compensatory changes in O2-binding and cardiac output precluded an impairment to O2 transfer. Equilibration at the tissues (Et,Ot,O2) in FW was less effective than at the gills (Eb,Ob,O2 but progressively improved with hypersaline exposure reversing this trend. Although effects of increased salinity on O2 equilibrium characteristics were qualitatively similar in vivo and in vitro, some interesting quantitative differences are discussed.

scholarly journals A Qualitative Analysis of Affect Signs in Telecommunication Dialogues

2021 ◽  
Author(s):  
Edmunds Vanags ◽  
Keyword(s):  
Content Analysis ◽  
Qualitative Study ◽  
Qualitative Analysis ◽  
Demographic Factors ◽  
Phenomenological Approach ◽  
Core Affect ◽  
Complete Saturation ◽  
Expression Of Emotions ◽  
Universal Expression

There is growing evidence in the science of psychology that affective phenomena are not homogeneous and that their manifestations may vary across cultures and under the influence of contextual and demographic factors. Given that there is no clear universal expression of emotions and mood in human behavioral processes, it is necessary to continue to study the heterogeneity of the observed features in language and speech. This qualitative study analyzes the dialogues of 40 individuals in the field of telecommunications and, using a content analysis and phenomenological approach, describes lexical and non-lexical signs that could indicate features of affect. It can be observed that complete saturation has not been obtained within the framework of these data, which may indicate a wide variation of verbal and non-verbal affect features at both intra-individual and inter-individual levels and indicate different possible dialects of affect features. In addition, inter-rater reliability was determined and its results suggest that the determination of affective features may be subjective, contextual, in the absence of predefined reference criteria even in valence and activation dimensions of core affect.

scholarly journals Evaluation and identification of walnut heartwood extractives for protection of poplar wood

BioResources ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 59-69
Author(s):  
Seyyed Khalil Hosseini Hashemi ◽  
Ahmad Jahan Latibari
Keyword(s):  
Weight Loss ◽  
Trametes Versicolor ◽  
Juglans Regia ◽  
White Rot ◽  
White Rot Fungus ◽  
Poplar Wood ◽  
Vacuum Desiccator ◽  
Highest Weight ◽  
Complete Saturation ◽  
Heartwood Extractives

Walnut (Juglans regia L.) heartwood extractives were identified and their potential for protection of poplar wood was evaluated. Test specimens were prepared from poplar wood (Populus nigra L.) to meet BS 838:1961 requirements. Samples were impregnated with heartwood extractive solution (1.5, 2.5, and 3.5% w/w in ethanol-toluene), followed by 5 hours vacuum desiccator technique to reach complete saturation. Impregnated specimens were exposed to white-rot fungus (Trametes versicolor) for 14 weeks according to BS 838:1961 applying the kolle-flask method. The weight loss of samples was determined after exposure to white-rot fungus. The highest weight loss (36.96%) was observed for untreated control samples and the lowest weight loss (30.40%) was measured in samples treated with 1.5% extractives solution. The analyses of the extracts using GC/MS indicated that major constituents are benzoic acid,3,4,5-tri(hydroxyl) and gallic acid (44.57 %). The two toxic components in the heartwood are juglone (5.15 %) and 2,7-dimethylphenantheren (5.81 %).

scholarly journals Determinants of fecal and urinary iron excretion in desferrioxamine- treated rats

Blood ◽  
1978 ◽  
Vol 51 (3) ◽  
pp. 415-423 ◽  
Author(s):  
C Hershko
Keyword(s):  
Binding Capacity ◽  
Iron Chelation ◽  
Subcutaneous Infusion ◽  
Alternative Pathways ◽  
Complete Saturation ◽  
Continuous Subcutaneous Infusion ◽  
Chelated Iron ◽  
Iron Binding Capacity ◽  
Chelation Of Iron

Abstract Radioiron excretion in the urine and feces after continuous subcutaneous infusion of desferrioxamine (DF) was studied in normal and hypertransfused rats in whom reticuloendothelial and parenchymal iron stores had been labeled by selective 59Fe probes. The existence of two alternative pathways for the chelation of iron in vivo by DF was indicated by the results. The first pathway was intracellular chelation in hepatocytes with chelated iron excreted through the bile only. The second pathway, which was extracellular, could only be activated after saturation of the transferrin iron binding capacity, with the chelated iron excreted by the kidneys. The last mechanism was probably identical with the mode of action of diethylenetriaminepentaacetic acid (DTPA). Further studies will be required in order to establish whether the enhancement in iron chelation obtained by the continuous infusion of DF in patients with complete saturation of circulating transferrin may or may not be related to the extracellular mechanism of iron chelation in hypertransfused rats.

scholarly journals THE DISTRIBUTION OF THE IMMUNE BODIES OCCURRING IN ANTIPNEUMOCOCCUS SERUM

1915 ◽  
Vol 21 (2) ◽  
pp. 133-145 ◽  
Author(s):  
Oswald T. Avery
Keyword(s):  
Carbon Dioxide ◽  
Sodium Chloride ◽  
Ammonium Sulphate ◽  
Promising Method ◽  
Complete Saturation

The immune bodies of antipneumococcus serum are completely precipitated by 38 to 42 per cent. saturation with ammonium sulphate. They are incompletely precipitated by (a) ammonium sulphate in less than 38 per cent. saturation, (b) saturation with sodium chloride, (c) dilution and saturation with carbon dioxide, (d) removal of crystalloids by dialysis. The immune bodies of antipneumococcus serum are, therefore, associated or combined with that fraction of the globulins precipitated by 38 to 42 per cent. saturation with ammonium sulphate. The immune body fraction does not correspond exactly with the ordinary euglobulin (one-third saturation with ammonium sulphate or complete saturation with sodium chloride) or with the insoluble globulins precipitated by carbon dioxide or dialysis. These fractions carry with them only a part of the immune bodies. Neither the albumin nor that fraction of the globulin not precipitated by 38 to 42 per cent. saturation of ammonium sulphate contain any of the demonstrable antibodies. The most promising method for the practical purification of the immune bodies occurring in antipneumococcus serum appears to be precipitation by 38 to 42 per cent. saturation with ammonium sulphate.

scholarly journals STUDY OF THE KINETICS OF DRYING IRON (II) SULFATE HEPTAHYDRATE BY FILTRATION METHOD

ScienceRise ◽  
2021 ◽  
pp. 11-21
Author(s):  
Nadiia Tsiura ◽  
Diana Kindzera ◽  
Iryna Huzova ◽  
Volodymyr Atamanyuk
Keyword(s):  
Moisture Content ◽  
Material Balance ◽  
Filtration Method ◽  
Sulfate Heptahydrate ◽  
Calculated Dependence ◽  
Material Layer ◽  
Kinetic Coefficients ◽  
Complete Saturation ◽  
Kinetics Of ◽  
Technological Product

The object of research: kinetics of filtration drying process of iron (II) sulfate heptahydrate. Solved problem: to obtain the calculated dependence of the kinetics of filtration drying, which predicts the nature of the change in the moisture content of the material in time during the period of complete saturation of the thermal agent with moisture in the range of heights of the material layer 30.10-3–120.10-3 m and the speeds of the thermal agent 0.46–1.61 m/s. Main scientific results: The kinetics of filtration drying of iron (II) sulfate heptahydrate was investigated at different heights of the material layer and pressure drops over dry material, which means at different speeds of movement of the thermal agent. A certain critical moisture content, which is Wcr=0.065 kg H2O/kg dry mat and the time it reaches at different heights of the material layer and the speeds of movement of the thermal agent. Based on the solution of the system of differential equations of material balance in the layer and the kinetics of drying, the kinetic coefficients for iron (II) sulfate heptahydrate a=15.75 1/m, α=3.03.10-3 1/s were determined, which made it possible to obtain the calculated dependence of the kinetics drying, which predicts the nature of the change in the moisture content of the material over time during the period of complete saturation of the thermal agent with moisture in the range of heights of the material layer H=30.10-3–120.10-3 m and the velocities of the thermal agent υ=0.46–1.61 m/s. The area of practical application of the results: enterprises for the production of titanium (IV) oxide with the production of iron (II) sulfate heptahydrate as a by-product and enterprises specializing in the manufacture of pigments based on iron (II) sulfate heptahydrate. Innovative technological product: iron (II) sulfate tetrahydrate (FeSO4•4H2O, rosenite), obtained as a result of drying by the filtration method. Scope of application of the innovative technological product: in the production technology of iron oxide pigments.

scholarly journals Simulation and estimation of gene number in a biological pathway using almost complete saturation mutagenesis screening of haploid mouse cells

BMC Genomics ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 1016 ◽  
Author(s):  
Masahiro Tokunaga ◽  
Chikara Kokubu ◽  
Yusuke Maeda ◽  
Jun Sese ◽  
Kyoji Horie ◽  
...  
Keyword(s):  
Saturation Mutagenesis ◽  
Biological Pathway ◽  
Gene Number ◽  
Complete Saturation ◽  
Mouse Cells

CATALYTIC HYDRODESULPHURIZATION OF THIOPHENE: IV. THE METHYLTHIOPHENES

1963 ◽  
Vol 41 (8) ◽  
pp. 1966-1971 ◽  
Author(s):  
P. Desikan ◽  
C. H. Amberg
Keyword(s):  
Steady State ◽  
Steady State Flow ◽  
Reaction Sequence ◽  
State Flow ◽  
Complete Saturation ◽  
Cobalt Molybdate ◽  
Flow Techniques

The hydrodesulphurization of 2- and 3-methylthiophene was studied over a sulphided, alumina-supported cobalt molybdate catalyst in a microreactor permitting the use of both pulse and steady-state flow techniques. The higher rates obtained with the 3-isomer were interpreted in terms of involvement of the α-carbon. The results were found to conform to the predominant reaction sequence proposed earlier for thiophene: C—S bond fission followed by diene and monoolefin formation and complete saturation. Some ancillary experiments on the hydrogenation of C5-olefins were reported.

Mendelian Genes and Rates of Development in Gammarus Chevreuxi

1927 ◽  
Vol 5 (2) ◽  
pp. 112-134 ◽  
Author(s):  
E. B. FORD ◽  
J. S. HUXLEY
Keyword(s):  
Cross Section ◽  
Equilibrium Position ◽  
Low Temperatures ◽  
Sexual Maturity ◽  
Red Pigment ◽  
Wild Type ◽  
Pigment Formation ◽  
Melanin Formation ◽  
Complete Saturation ◽  
Theoretical Considerations

In the present paper the following facts and theoretical considerations have been brought forward: (1) All the mutations so far examined which influence the colour of the facets (as opposed to total absences of black and red pigment) in the eyes of Gammarus chevreuxi appear to act by modifying the time relationships governing the deposition of melanin. (2) All coloured eyes are at first colourless, and then become scarlet owing to the formation of a red pigment soluble in alcohol; later they may darken by the deposition of melanin. (3) In the normal black eye (RR), melanin begins to be deposited about 2 days before hatching (at 23° C ) ; its deposition is very rapid, and complete saturation, giving a dense black colour, is reached at or about extrusion. (4) In red (rr) eyes the time of onset and the rate of melanin formation is always slower. The rate may be modified by a factor "s" slowing it down considerably, and a factor "m" slowing it down to a less degree. (5) At 23° C. rrSSMM eyes begin to darken at about 4 to 6 days after extrusion, and reach an equilibrium position (of a deep chocolate colour) in about 3 weeks. (6) Under the same conditions, rrssMM eyes begin to darken at about 4 to 8 days, and reach an equilibrium (of a lighter chocolate shade) in about 5 to 7 weeks. The degree of phenotypic divergence between the colours of rrSS and rrss is at first nil; it then increases to a maximum at about 2½ to 3 weeks from extrusion, after which it diminishes once more. It is, however, not completely obliterated in the adult. (7) In addition a factor "d" has been found which delays the onset of rapid pigment development until sexual maturity. The rate of subsequent darkening is that characteristic of the other factors present. (8) Other agencies also influence melanin formation. In rr eyes melanin is formed rapidly at 23° C. (above which temperature the stocks are unhealthy), less rapidly at 20° C., and only to a slight extent, beginning after about four months, at or below 14° C. (9) In RR (wild type and black-no-white) eyes, however, low temperatures merely cause a slight delay in melanin formation. (10) The area of the eye also influences the colour. The eye facets continue to increase in size after the melanin has attained its equilibrium position. Thus the same amount of pigment is spread over a greater area, and the eye appears slightly paler. This again does not apply to RR eyes, presumably owing to the large quantity of black pigment formed. New facets are added so long as growth continues. Since they behave as distinct units in pigment formation, those which have appeared most recently will be bright red while the older ones are already blackish. (11) Other instances are given of genes which appear to control rates of development in various animals. (12) It is suggested that the effects of multiple allelomorph series (e.g. for eye-colour in Drosophila) may represent a cross-section through a series of developmental curves of one and the same substance, the curves differing as regards rates of formation of the substance, times of onset of deposition, and final level of the equilibrium position obtained.

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