Determination of gross α-activity in urine by microprecipitation with LaF3 and α-spectrometry

This paper describes a method for the determination of gross -activity (actinides) in urine. The method consists of a coprecipitation of actinides as Fe/Ca phosphates and hydroxides, a purification as iron phosphate and a LaF₃ source preparation; -spectrometry is then carried out without any electroplating procedure. The average recoveries of the method for actinides (except uranium) were about 83.8±8.1%. With a counting time of 1440 min and a counting efficiency of 38% the detection limit was 0.25 mBq/l (6.8 fCi/l). The gross -activity in urine blanks ranged from 0.35 to 0.80 mBq/l (9.4 to 22 fCi/l).     

Structure-Activity Relationship for Insecticidal Steroids. VI. 5,6-Disubstituted β-Sitosterols

The toxicity of steroids 1-14 for Colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by a contact-intestinal method. The most active are 3,5-dihydroxy-6-ketone 4a and 5-hydroxy-3,6-diketone 8a.     

Methode zur gleichzeitigen Bestimmung von Pregnandiol und Pregnantriol aus einer Urinprobe

Zusammenfassung Eine chemische Methode zur routinemäßigen Bestimmung von 5-Pregnan-3,20-diol und 5-Pregnan-3,17,20-triol aus einer Urinprobe wird beschrieben. Die Methode besteht aus folgenden Schritten:1. Enzymatische Hydrolyse; 2. Extraktion und Reinigung; 3. Säulen-Chromatographie zur Trennung von Pregnandiol und Pregnantriol; 4. Farbreaktion zur Bestimmung von Pregnantriol; 5. Reinigung der Pregnandiol-Fraktion durch Oxydation mit Kaliumpermanganat und erneute Säulen-Chromatographie; 6. Farbreaktion zur Bestimmung von Pregnandiol. Die Brauchbarkeit der Methode wird aufgrund der Zuverlässigkeitskriterien: Spezifität, Richtigkeit, Genauigkeit, Empfindlichkeit nachgewiesen.

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Method for the simultaneous determination of pregnanediol and pregnanetriol in one urine sample

A chemical method is described for the routine assay of both 5-pregnane-3,20-diol and of 5-pregnane-3,17,20-triol in one urine sample. The method involves the following steps: (1) enzymatic hydrolysis of the urine; (2) extraction of the hydrolysed urine and purification of the extract; (3) column chromatography for the separation of pregnanediol and pregnanetriol; (4) colour reaction for the determination of pregnanetriol; (5) further purification of the pregnanediol fraction by oxidation with potassium permanganate and column chromatography; (6) colour reaction for the determination of pregnanediol. The practicability of the method has been checked by the following criteria of reliability: specificity, accuracy, precision and sensitivity.

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Dissertation, Med. Fakultät, Univ. Bonn 1970     

Transformed steroids. 112. 17α-Fluoro-16α-amino-20-ketosteroids

Conclusions The reaction of 16,17-epiminopregnenolone 20-carbethoxyhydrazone with HF and subsequent hydrolysis leads to 17-fluoro-16-amino-20-ketosteroids.See [1] for Communication 111.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1637–1639, July, 1980.     

Steam reforming of methanol over Cu/ZrO2. Role of ZrO2 support

Cu/ZrO₂ was highly active and selective for the title reaction. The activity obtained exceeded greatly that obtained over Cu/SiO₂. It was shown that the precursors highly dispersed on zirconia support were readily reduced to very fine particles of metallic copper.

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Cu/ZrO₂ . Cu/SiO₂. , , , .

     

Poissonian stationary distribution: A degenerate case of stochastic kinetics

There is practically no chemical reaction with independent reaction rates having Poissonian stationary (equilibrium) distribution. There exists, hovewer, a manifold of reactions with dependent reaction rates and with Poissonian stationary distribution. In this case the explicit form of the interdependence between the reaction rates is also given.

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, () . , . .

     

Steroid compounds of marine sponges. VII. Preparation of derivatives of sokotrasterol and halistanol sulfates and structure-activity interrelationships among these compounds

Five new sulfated derivatives of sokotrasterol and halistanol have been obtained: 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate); 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate) 23-palmitate; 24,25-dimethyl-5-cholestane-2,3,6-triol 3-(sodium sulfate); 24,25-dimethyl-5-cholestane-2,3,6-triol 6-(sodium sulfate); and 24,25-dimethyl-5-cholestane-2,3,6-triol 2,6-di(sodium sulfate). The inhibiting and membranolytic properties of the polysulfated steroids from sponges and their derivatives have been studied. It has been shown that physiological activity in this series of compounds depends on biphilicity.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 441–445, July–August, 1986.     

Top soil environmental radioactivity in Akwa Ibom State of Nigeria

A survey of top soil environmental radioactivity in Akwa Ibom State of Nigeria has bean investigated. The results vary considerably from one environment to another ranging between a minimum of 161 mBq·g^–1 and a maximum value of 648 mBq·g^–1 -activity. The work reveals that hospitals and health centres lead in top soil radioactivity with the highest mean values of (378 mBq·g^–1) and (294 mBq·g^–1) followed closely by industrial areas with mean values of (372 mBq·g^–1) and (283 mBq· g^–1) trailing beaches and recreation centres having average values of (364 mBq·g^–1) and (273 mBq·g^–1). Lower levels of top soil radioactivity were observed mostly in environments with high level human interaction activity such as schools, offices, environments and recreation centres. An overall top soil mean of 342 mBq·g^–1 -activity, 271 mBq·g^–1 -activity and 71 mBq·g^–1 -activity were observed in the State.     

Methods for finding steady-state solutions of mathematical models for chemico-technological schemes

Gradient and Newton methods are suggested for searching for steady-state solutions of chemico-technological schemes to obtain synthetic fuels.

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A further study of the substrate specificity in the reduction of 20-oxosteroids with a culture ofActinomyces roseochromogenus

Conclusions A culture ofActinomyces roseochromogenus ATCC 3347 reduces 17-hydroxy- and 16, 17-epoxy-20-oxopregnenes to the corresponding 20-alcohols, but is incapable of reducing 17-acetoxy-, 17-methyl-, and 16-methylprogesterones or 17-unsubstituted 20-oxopregnenes. The results obtained show that the presence of the side chain in a conformation favorable for the formation of 20-alcohols in the reduction of 20-oxosteroids with complex metal hydrides is in itself insufficient for the reduction of the 20-oxosteroids by a culture ofActinomyces roseochromogenus, which also reduces the 20-oxo group of 17-pregnenes.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 38–47, 1970     

Redistribution kinetics of isotope molecules due to reversible bimolecular reactions with several atomic channels

Isotope kinetic equations for reversible bimolecular reactions describe the rearrangement of atoms in activated complexes. It has been established from the model reaction CH₄+HCH₃+H₂ that the isotopic homoexchange of methane via two atomic channels is given by one set of equations with different sets of parameters.

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- . CH₄+HCH₃+H₂ , .

     

The maximum kinetic mechanism and rate constants in the H2?O2 system

The maximum (in a combinatorial sense) kinetic mechanism of hydrogen oxidation is defined and the rate constants of all elementary steps are given. The possible error limit is given for each elementary step.

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( ) . .

     

Kinetic model for methanol conversion over Mg-ZSM-5 zeolite

The catalytic conversion of methanol to olefins over ZSM-5 zeolite modified by ion exchange with Mg exhibits an autocatalytic character. On this basis an overall kinetic model of the reaction was proposed which allowed the determination of rate constants and apparent activation energy.

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ZSM-5, Mg, . , .

     

Liquid-phase hydrogenation of cyclohexene by dihydrogen in the presence of dimolybdenum tetraacetate

Catalytic liquid-phase hydrogenation of cyclohexene in DMF by dihydrogen in the presence of dinuclear bridged complex Mo₂(OAc)₄ has been studied. A kinetic equation for the steady-state rate of cyclohexene hydrogenation and the activation parameters are suggested.

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Mo₂(OAc)₄. .

     

Oxidative transformations of labdane diols. III. Preparation of acids with a strobane skeleton from larixol

It has been shown that the oxidation of larixol with chromic acid mixture forms methyl 6-oxo-8,13-epoxystroban-14-oate, methyl 6-oxo-8,13-epoxystroban-14-oate, and 6,13-dioxo-14,15-bisnorlabd-7-en-17-oate.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 697–703, November–December, 1986.     

Kinetics and mechanism of iodination of p-aminobenzoic acid and o-aminobenzoic acid. Novel catalytic behavior of added phosphate buffers

Kinetics of iodination ofp-aminobenzoic acid ando-aminobenzoic acid at different pH and solvent media has been studied. The order of the reaction with respect to the iodinating agent and substrates was established. Reactions were carried out with buffer mixtures of primary and secondary phosphates and catalytic constants were evaluated. Effect of temperature and dielectric constant of solvents used were studied. Suitable mechanism and composite rate law have been suggested.

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Pulchellin C and inuchinenolide C from Inula caspica

The pseudoguaianolide inuchinenolide C and the eudesmanolide pulchellin C have been isolated for the first time from the flower heads and leaves ofInula caspica Blume, and their spatial structures have been established by an x-ray structural experiment as 2,6-diacetoxy-6-hydroxy-1,7(H),8,10(H)-pseudoguai-11(13)-en-8,12-olide and 2,3-dihydroxy-5,7,8(H)-eudesma-4(15),11(13)-dien-8,12-olide, respectively.Institute of Organic Synthesis and Coal Chemistry, Academy of Sciences of the Kazakh SSR, Karaganda. A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 748–757, November–December, 1990.     

Studies on the use of passivated ion implanted detectors in alpha spectrometry for the determination of actinides

An experimental evaluation of the recently available passivated ion-implanted detectors, which appear promising for high resolution -spectrometry, is presented in terms of % tail contribution per unit -activity ratio, peak to valley ratio, and resolution /FWHM/. The two IPE detectors with areas of 20 mm² and 450 mm² were used for comparing these parameters. It is seen that the smaller area detector provides a better resolution for single nuclide sources, but there is no significant difference for sources containing nuclides with close lying -energies, e.g.,²³⁹Pu,²⁴⁰Pu. Further, the large area detector gives less tail contribution and should be preferred to minimize the error in -activity ratio determinations. However, the small area detector offers a possibility of qualitative or semiquantitative determination of nuclides with close lying -energies.     

Reduction of some D-homosteroids with an aromatic a ring with alkali metals under the conditions of Birch's reaction. II.

Summary 1. The reduction of 3-methoxy-D-homoestra-1, 3, 5(10), 8-tetraen-17a-ol (IV) with alkali metals in the presence of ammonium chloride or alcohol gives, in addition to 8, 9-dihydro derivatives, the 8, 9 and 8, 9-epimers, the structure of which has been shown partly by independent synthesis and partly on the basis of chemical reactions and NMR spectra.2. Hydrolysis of the reduction products has given 19-nor-D-homotestosterone (III) and its 8- and 9, 10-epimers (V) and (VI). The ketols (III) and (V) readily form hydroperoxides in air.3. The reduction of the ethylene ketal of 3-methoxy-D-homoestra-1, 3, 5(10), 8-tetraen-17a-one (XIX) takes place stereodirectively and gives only 8, 9-dihydro derivatives.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 2, pp. 90–100, 1965     

Determination of the half-lives of transactinium isotopes by relative activity method

Relative activity method offers the potentiality of providing half-life values over a wide range in a short time for different -emitting transactinium isotopes. The method involves the preparation of a synthetic mixture using another isotope of the same element followed by the determination of atom ratio and -activity ratio by thermal ionization mass spectrometry and -spectrometry, respectively. A double dilution technique is described which helps in maintaining the atom ratios as well as -activity ratios close to unity so that these could be determined with high precision and accuracy. Results obtained on the half-lives of²³²U,²³⁸Pu,²⁴²Pu and²⁴³Am using double dilution technique in relative activity method are summarized. Requirements, advantages and applications of this technique for determining the half-lives of other transactinium isotopes are presented.