Development of90Sr/90Y (β) surface applicators by powder metallurgical technology

In recent years, -particle surface applicators (such as³²P,⁹⁰Sr) have been widely used in treating some diseases of dermotology, ophthalmology, otolaryngology etc. in China. The powder metallurgy and metal rolling technology of strontium-90/yttrium-90 () sources and the manufacture process of⁹⁰Sr/⁹⁰Y surface applicators are described in this paper. For this kind of radioactive sources, the strontium-90 insoluble compound is incorporated in a silver matrix which is sandwiched between the gold (or silver) face and the silver backing. The external surface of strontium-90 foil source is then protected by palladium or tungsten-nickel alloy coating. The characteristics of strontium-90 surface applicator are of uniform dose rate, small self-absorption and safety in use, so it can satisfy the requests of medical care.     

Rapid determination of90Sr by Compton suppression gamma-ray spectrometry

This work presents a low-level background gamma spectrometry system capable of achieving rapid determination of⁹⁰Sr without chemical separation, in a soil sample when the⁹⁰Sr to -ray emitting nuclide concentration ratio exceeds 10. The system consists of a highly efficient HPGe central detector operated in coincidence or anticoincidence with a NaI(Tl) guard detector and a NaI(Tl) backscatter detector. Experimental results indicate that the bremstrahlung radiation from a pure -emitter can be distinguished with respect to the differences in normal and coincidence spectra. The⁹⁰Sr activity can be directly detemined in the sample in less than 1 hour with a minimum detectable concentration (MDC) estimated at 0.002 Bq·g^–1 for a sample containing no appreciable -ray nuclides or other high energy, -emitting nuclides. In actual measurement, a 0.06 Bq·g^–1 MDC for contaminated soils is achieved.     

Liquid scintillation spectrometry of beta-emitters in marine samples

Liquid scintillation spectrometry has become the most widespread method for quantitative analysis of low level -emitters in environmental samples. This technique has been applied in the measurements of ²⁴¹Pu, ³H and ⁹⁰Sr in seawater and sediment samples. ²⁴¹Pu can be measured by direct analysis of an electrodeposited source using - discrimination or by extraction of electrodeposited plutonium into a liquid form compatible with scintillation cocktail. Sediment from Mururoa and Fangataufa atolls showed activities ranging from 18 to 44 Bq/kg. A sediment profile sampled around Bikini Atoll in 1997 showed ²⁴¹Pu activities ranging from 0.3 to 30 Bq/kg. ³H activities in pore water sediment from Mururoa and Fangataufa atolls were of the order of 10³ Bq/m³ which demonstrated its underground origin. ⁹⁰Sr was measured in the presence of ⁹⁰Y. The counting efficiency was 92.41.5% and the background 0.027±0.001 s^-1. The average chemical recovery for ⁹⁰Sr was 673%.     

Karakanine — A new alkaloid from the epigeal part of Aconitum karakolicum

A new alkaloid, which has been called karakanine, has been isolated from the total alkaloids of the epigeal part ofAconitum karakolicum. The structure of karakanine as 8,14-dihydroxy-16-methoxy-4-methyl-N-ethyl-1,19-epoxyaconitane has been proposed on the basis of a study of its IR, PMR, mass, and¹³C NMR spectra, and has been confirmed by its conversion into karakoline.Institute of Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedeninii, No. 1, pp. 62–64, January–February, 1993.     

Dimerization of N-methylanabasine in the presence of metallic sodium

In a study of the dimerization of N-methylanabasine in the presence of metallic sodium under conditions for the dimerization of pyridine, it was found that the reaction does not take place at room temperature while at 50–70° C it leads to the formation of,-di(1-methylpiperid-2-yl)-,-bipyridyl. Oxidation of the latter yielded 4,4-bipyridyl-5, 5-dicarboxylic acid, the decarboxylation of which gave,-bipyridyl.     

Reaction of methylmagnesium iodide with steroid keto oxides

Summary The reaction of the 3-acetate of the 20-ketal of 16,17-oxido-⁵-pregnenol-3-one-20 with methylmagnesium iodide and subsequent hydrolysis of the reaction product yielded 16-methyl-⁵-pregnenediol-3 –17-one –20. 18-Nor-17-methyl-17-iso-^5.11-pregnadienediol-3,16-one-20 was formed as a by-product.     

Inclusion of Ring A of Cholesterol Inside the β-Cyclodextrin Cavity: Evidence from Oxidation Reactions and Structural Studies

The disposition of cholesterol inside the -cyclodextrin cavity(-CD) was deduced from oxidation of cholesterol secondary alcoholgroups by Ca(OCl)₂ and H₂O₂ in thepyridine–acetic acid system. The amount of cholest-4-ene-3-one formedwas found to be proportional to the concentration of -cyclodextrin,resulting in 56.1% of ketone. The oxidation rate was enhanced by-cyclodextrin and its methyl, polymer and 1 : 1copper(II)–-cyclodextrin derivatives. Detailed investigationsinvolving UV-visible, ¹³C- and ¹H-NMR(T₁, 1D NOE and ROESY) spectroscopic studies were carried out.A binding constant value of 15,385 ± 1500 M^-2 wasobtained for the 2 : 1heptakis-2,6-di-O-methyl--cyclodextrin(DM-CD) : cholesterolcomplex in chloroform from UV studies. Proton and solid state¹³C-CP MAS spectra of the -CD–cholesterol mixtureshowed large magnitude shifts for the protons from the wider end of the-CD cavity as well as those of ring A and ring B of cholesterol. Both1D NOE and ROESY measurements indicated the proximity between ring A andring B protons of cholesterol and the wider end protons of -CD andDM-CD. Besides, analysis of _c,_i and tau;_m from T₁measurements showed not only a lowering of rotational motions but a value of 0.016–0.048 for some of the cholesterol protons, typical of aweak complex. Based on these studies, a probable structure for the 2 : 1complex involving two molecules of -CD/DM-CD was proposed withportions of ring A and ring B being present inside the wider end of the-CD/DM-CD cavity and ring D and the side chain attached atposition 17, projecting into the wider end of the secondCD/DM-CD molecule.     

Beta-spectroscopic separation of90Sr,90Y and89Sr with a scintillation detector

A -spectroscopic method for measurement of the isotope ratios and absolute activities of⁹⁰Sr,⁹⁰Y and⁸⁹Sr with an organic scintillator is described and tested. The correction factors for absorption in the sample and the detector window are calculated. The method can be used for rapid estimation of ratios and absolute activities of pure -emitters after a nuclear accident.Supported in part by the International Atomic Energy Agency, RC5633 and the National Fund for Scientific Research (Bulgaria).     

Trans-cis Photoisomerization of 1-Methyl-4-(4′-hydroxystyryl)pyridinium in inclusion complexes ofβ-cyclodextrin and its derivatives

The effects of -cyclodextrin (-CyD), heptakis(2,6-di-O-methyl)--cyclodextrin (DMCyD) and heptakis(2,3,6-tri-O-methyl)--cyclodextrin (TMCyD) ontrans-cis photoisomerization of 1-ethyl-4-(4-hydroxystyryl)pyridinium (POH) have been studied in aqueous solutions. The ratio of [cis]/[trans] for POH in the photostationary state at pH 8.54 was remarkably reduced by the presence of CyD or DMCyD. The reduction of the [cis]/[trans] ratio in the photostationary state was explained in terms of the shift of the equilibrium of POH ₊ ^trans PO _trans + H^– toward PO _trans formation. The binding constants of CyD and DMCyD for PO _trans were 2.00- and 1.36-fold larger than those for POH ₊ ^trans , respectively. The binding constants of TMCyD for both species are much smaller than those of CyD and DMCyD. This result indicates that PO _trans , which has a betain structure, forms stable complexes with CyD and DMCyD with its hydrophobic parts inside and the charged parts outside the CyD cavities.     

Neue Ergebnisse zur Polymorphic desβ-Naphthols und deren Auswirkung auf die Phasendiagramme der Naphthalingruppe

Zusammenfassung Die frühere Annahme, daß die beiden Modifikationen von-Naphthol den gleichen Schmelzpunkt besitzen und somit einen Grenzfall der Enantiotropie darstellen, wurde durch differentialthermoanalytische Untersuchungen widerlegt. Die beiden Modifikationen stehen zueinander im Verhältnis der Monotropie mit der allerdings nur geringen Schmelzpunktsdifferenz von 0,5°. Auch die IR-Spektren der beiden Kristallformen bestätigen das Vorliegen einer Monotropie.Für die Phasendiagramme der Naphthalingruppe, an denen-Naphthol beteiligt ist, ergeben sich Korrekturen. Da die instabile Mod. II die mit Naphthalin korrespondierende Kristallform ist, liegt in dem System Naphthalin--Naphthol keine lückenlose Mischkristallreihe vor (Typ. I, Roozeboom), sondern es wird eine Mischungslücke gebildet, denn das System besteht aus zwei Mischkristallphasen (Typ. IV). Auch im System-Naphthol--Naphthylamin tritt auf der-Naphtholseite eine bisher nicht erkannte Phasenüberschneidung auf und anstelle von Typ. III wird Typ. V (Roozeboom) gebildet.Schmelzdiagramme ohne Mischkristallbildung-Naphthol--Naphthol,-Naphthol--Naphthylamin) sind von einer Korrektur nur insofern betroffen, als die Kurvenäste der beiden Modifikationen des-Naphthols nicht von einem Punkt ausgehen und der stabile Kurvenast nicht als Mod. II, sondern als Mod. I bezeichnet werden muß.

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New results on the polymorphism of-naphthol and its effects on the phase diagrams of the naphthalene group

Summary The earlier assumption that the two modifications of-naphthol have the same melting point and thus constitute a borderline case of enantiotropy was disproved by differential thermoanalytic investigations. The two modifications only have the slight difference in melting point of 0.5°. The IR spectra of the two crystal forms confirm the presence of monotropy.There are corrections for the phase diagrams of the naphthalene group in which-naphthol is involved. Since the unstable modification III is the crystal form corresponding to naphthalene, there is no unbroken series of mixed crystals in the naphthalene--naphthol system (Type I, Roozeboom), but a mixing gap is formed since the system consists of two mixed crystal phases (Type IV). A phase overlap which had not been previously recognized also occurs on the side of-naphthol in the-naphthol--naphthylamine system; the Roozeboom Type V is formed instead of Type III. The melting diagrams of a mixed crystal formation (-naphthol--naphthol,-naphthol--naphthylamine) are affected by a correction only to the extent that the curve branches of the two modifications of-naphthol do not begin at one point and the stable branch of the curve must be designated not as modification II but as modification I.

     

Polarographische Bestimmung der Stabilitätskonstanten ammoniakalischer Magnesiumkomplexe

Zusammenfassung Die polarographische Methode des Indikatorions wurde zur Untersuchung der Komplexbildung des Mg²⁺-Ions mit Ammoniak verwendet. Es wurden die Stabilitätskonstanten ₁,₂,₃,₄ und ein annähernder Wert für ₅ bestimmt.

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Investigation of stability constants of magnesium ion-ammonia complexes

The polarographic method with indicator ion was used for investigation of magnesium ion complexation with ammonia. The numerical values of the stability constants ₁,₂,₃,₄ and the approximative value of ₅ were determined.

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Mit 2 Abbildungen     

Steroids of the spirostan and furostan series from Nolina microcarpa I. Structures of nolinospiroside C and nolinofurosides A and C

In addition to the know steroid sapogenin (25S)-ruscogenin (I), three new glycosides have been isolated from the leaves ofNolina microcarpa S. Wats. (family Dracaenacea), and the following structures are suggested for them: (25S)-spirost-5-ene-1,3-diol 1-O--D-fucopyranoside (nolinospiroside C, II), (25S)-furost-5-ene-1,3,22,26-tetraol 1-O--D-fucopyranoside (nolinofuroside A, III), and (25S)-furost-5-ene-1, 3, 22, 26-tetraol 1-O--D-fucopyranoside 26-O--D-glucopyranoside (nolinofuroside C, V).M. V. Frunze Simferopol' State University. Institute of Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 672–678, September–October, 1991.     

The structure of cycloglobiceposide B fromAstragalus globiceps

Two known compounds of the cycloartane series—cyclosieversiosides C and G—and the new glycoside cycloglobiceposide B—24R-cycloartane-3,6,16,24,25-pentaol 16,25-di-O--D-glucopyranoside 3-O--D-xylopyranoside—have been isolated from the roots ofAstragalus globiceps Bunge. The structures of the glycosides were established on the basis of the results of enzymatic and total hydrolysis and also of¹H and¹³C NMR spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 216–219, March–April, 1999.     

First Example of Construction of a Pyrrole Ring Bonded to a Steroid System by the Trofimov Reaction

The oxime of ⁵-pregnen-3-ol-20-one reacts with acetylene in the KOH-DMSO system to form a mixture of products containing 3-vinyloxy-17-(1-vinyl-2-pyrrolyl)-⁵-androstene as the major product (63% yield) and also the O-vinyloxime of 3-vinyloxy-⁵-pregnen-20-one (10%), 3-vinyloxy-17- and 3-vinyloxy-17-⁵-pregnen-20-one (25%, 1:4 ratio).     

Controlled-potential coulometric studies on fluoride and sulphate complexes of neptunium (VI)

Fluoride and sulphate complexing of Np(VI) has been studied by controlled-potential coulometry at a constant ionic strength. The values of ₁ ^* and ₂ ^* for fluoride complexes were found to be 9.4 and 8.9, respectively, at an ionic strength =0.5. At an ionic strength =1.0, ₁ ^* and ₂ ^* obtained were 6.6 and 10.5, respectively. Sulphate complexing of Np(VI) was studied only at an ionic strength =0.5. The value of ₁ ^* obtained was 5.6.     

Bioactivities and structural studies of withanolides fromWithania somnifera

Four bioactive withanolides withalactone (1), withaoxylactone (2), quresimine-A (4-hydroxy, 3-methoxy-5, 6-epoxy-(22R)-witha-24-enolide) (3) and quresindne-B (4, 27 dihydroxy-3-methoxy-5, 6-epoxy-(22R)-witha-24-enolide (4) have been isolated from the herbs of Withania somnifera, Dunal (Solanaceae). The elucidation of their structures is based on extensive spectroscopic studies, such as¹H-NMR, COSY-45°, HMBC, HMQC HOHAHA, E.I., FAB (+ ve), and HR MS, etc.Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1200–1213, September, 1995.     

Sodium Dithionite Reduction of 2S,5R-(-)-menthone and R-(+)-pulegone in the Presence of β-Cyclodextrin and Hydroxypropyl-β-cyclodextrin

Menthone on reduction with sodium dithionite,showed a good amount of mentholformation in the water/DMF system, withincreasing -cyclodextrin (-CD)concentration from 47.0% for 0.1 equivalent of-CD to 93.5% for 1 equivalentof -CD. Increasing hydroxypropyl--cyclodextrin(HP-CD) gave higher menthol/neomenthol (M/N) ratiosfrom 2.8 to 3.5. In the case of pulegone,increasing -CD showed an increase in the formationof menthols in thewater/DMF system from 13.3% for 0.1 equivalent of-CD to 78.1% for 1equivalent of -CD with greater proportions ofneomenthol and neoisomenthol.However, HP-CD which showed only marginalenhancement in the formationof menthol from menthone (32.1–41%), exhibiteda greater proportion of mentholformation in the case of pulegone (55.1%).However, the phase-transfer capabilityof HP-CD was not found to be significant.     

Some Pharmaceutical Properties of a New Branched Cyclodextrin, 6-O-α-(4-O- α-D-Glucuronyl)-D-glucosylβ-cyclodextrin

Some physicochemical and biological properties of a new branched cyclodextrin, 6-O--(4-O--d-glucuronyl)-d-glucosyl--cyclodextrin GUG--CyD) were investigated. Further, theinteraction of GUG--CyD with several drugs was studied by the solubility and spectroscopic methods, and compared with those of parent -CyD and 6-O--maltosyl--CyD(₂--CyD).The hemolytic activity of GUG--CyD on rabbit erythrocytes was lower than those of -CyD and ₂--CyD. GUG--CyD and ₂--CyD showed negligible cytotoxicity on Caco-2 cells up to at least 0.1 M. The inclusion ability of GUG--CyD to neutral and acidic drugs was comparable to or slightly smaller than those of -CyD and ₂--CyD, probably because of a steric hindrance of the branched sugar. On the other hand, GUG--CyD showed greater affinity for the basic drugs, compared with -CyD and ₂--CyD, owing to the electrostatic interaction of its carboxylate anion with positive charge of basic drugs. Thus GUG--CyD may be useful as a safe solubilizing agent particularly for basic drugs.     

Evaluation of the uranium concentration in rocks at the μg/g level by a low-background Geiger-Müller counter

A low-background -counter and a simple direct method, based on total -counting, have been developed in order to estimate the concentration of uranium at the g/g level in ordinary rock samples. The method is a relative one; international standards have been used for calibration. Only 3 g of rock powder is needed. Combining this method with -spectrometry, direct determination of²³⁸U (independently of²²⁶Ra) becomes possible near the above concentration level.