Baseline assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat,Meghalaya, India

Radiation dose-risk assessment was carried out for cereal species Brassica compestris var. dichotoma, Oryza sativa var. Shalum1, Zea mays, Lactuca indica, Cumunis sativum, and Clocasia esculanta due to naturally available radionuclides ⁴⁰K, ²³⁸U and ²³²Th in Domiasiat area. The activity in biota and corresponding soil was measured by precipitation method using NaI(TI) detector. Transfer factor (TF) was for Oryza spp. (1.00E−01-⁴⁰K, 8.76E−05-²³²Th, and 9.11E−05-²³⁸U), for Brassica spp. (5.39E−01-⁴⁰K, 8.17E−04-²³²Th and 2.96E−04-²³⁸U) and for Zea spp. (3.41E−01-⁴⁰K, 5.84E−05-²³²Th, 8.87E−05-²³⁸U) etc., respectively. A detailed physio-morphological study of the biota and extensive investigation of ecosystem was carried out for assessment. The data was modeled using FASSET for dose estimation and obtained total dose was 1.58E−04  \upmu Gy h^-1 \upmu \hbox{Gy}\,h^{-1} in Oryza spp., 2.87E−04  \upmu Gy h^-1 \upmu \hbox{Gy}\,h^{-1} Brassica spp. and 6.90E−03  \upmu Gy h^-1 \upmu \hbox{Gy}\,h^{-1} in Zea spp. etc. The dose was compared with the UNSCEAR dataset for screening level dose for biota. Zea spp. was more susceptible for the chronic radiation exposure.     

An efficient one-pot synthesis of carbazates and dithiocarbazates through the corresponding alcohols using Mitsunobu��s reagent

A novel Mitsunobu-based protocol has been developed for the synthesis of carbazates and dithiocarbazates through the variety of corresponding primary, secondary and tertiary alcohols and various kinds of substituted hydrazines using Mitsunobu??s reagent and CO₂/CS₂ system, in good to excellent yields.     

An Efficient, One-Pot, Triton-B Catalyzed Synthesis of O -Alkyl- S -methyl Dithiocarbonates

A novel process for the one-step conversion of a variety of primary and secondary alcohols into their O-alkyl-S-methyl dithiocarbonates using methyl iodide catalyzed by the Triton-B/CS₂ system was developed. Thus, O-alkyl-S-methyl dithiocarbonates were obtained in very good to excellent yields. This protocol is mild and efficient compared to other methods.     

Die Kinetik der Entladung von Thorium (IV) in Gegenwart von Äthylen-bis(3-mercaptopropionat) an der Quecksilbertropfelektrode

The reduction of thorium at the dropping mercury electrode in presence of ethylene bis(3-mercaptopropionate) has been found to be irreversible and kinetically controlled. The kinetics of the electrode reaction has been investigated adopting the treatment followed byKoutecky.

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Studies on binuclear Schiff base derivatives having a Si?O?Sb (V) linkage

Schiff base derivatives of the type Ph₃Si? O? Sb(NO)Ph₃ (where NO represents the donor system of a monobasic bidentate ligand) have been synthesized. These are obtained as coloured solids; they are non-electrolytes and monomeric in nature, and have been characterized by elemental analysis, IR and ¹H NMR. Spectral studies suggest that silicon and antimony atoms are in tetra- and hexa-coordinated states, respectively.     

Triton-B Catalyzed Efficient One-Pot Synthesis of Dithiocarbamate Esters

A novel process for the one-step chemoselective conversion of alkyl halides into dithiocarbamates as protected amines was developed using benzyltrimethylammonium hydroxide (Triton-B) in presence of carbon disulfide. Thus, dithiocarbamates of different amines were prepared in very good to excellent yields. This protocol is mild, chemoselective, and efficient compared to other methods.     

Limit cycles and detailed balance in Fokker-Planck equations

A class of non-linear Fokker Planck equations with exactly known steady state solution is investigated and its relation with the models considered earlier in the literature is discussed. A characterisation of the absence of detailed balance and possible existence of limit cycles is given. The implications of detailed balance on the existence and the character of limit cycle behaviour are studied. It is shown that detailed balance does not determine the existence or non-existence of limit cycles but rather their character.     

Ionization and electron capture in neon K vacancy production from NNe collisions

Our measurements of Ne K and N K X-ray cross sections for N^{3+,4+,5+,6+,7+,} ions incident on a thin Ne target at energies from 9 to 54 MeV indicate that charge exchange plays a minor role compared to ionization in producing Ne K vacancies over that energy range.