Synthesis and in Vitro Antimicrobial Activity of 3-Aryl-4-S-benzyl-6-phenylimino-2-hepta-O-acetyl-β-D-lactosylimino-2,3-dihydro-1,3,5-thiadiazine (Hydrochloride)

The present work includes synthesis of several 3-aryl-4-S-benzyl-6-phenylimino-2-hepta-O-acetyl-β-D-lactosylimino-2,3-dihydro-1,3,5-thiadiazines (hydrochloride) by the interaction of N-hepta-O-acetyl-β-D-lactosyl isocyanodichloride and 1-aryl-5-phenyl-2-S-benzyl-2,4-isodithiobiurets. All these products have been characterized through the usual chemical transformations and infrared, ¹H NMR, and mass spectral analysis. The compounds were also screened for their antimicrobial activities.     

ICP-MS Measurement of Trace and Rare Earth Elements in Beach Placer-Deposit Soils of Odisha,East Coast of India,to Estimate Natural Enhancement of Elements in the Environment

Inductively coupled plasma mass spectrometry (ICP-MS) has been used to measure the concentration of trace and rare earth elements (REEs) in soils. Geochemical certified reference materials such as JLk-1, JB-1, and JB-3 were used for the validation of the analytical method. The measured values were in good agreement with the certified values for all the elements and were within 10% analytical error. Beach placer deposits of soils mainly from Odisha, on the east coast of India, have been selected to study selected trace and rare earth elements (REEs), to estimate enrichment factor (EF) and geoaccumulation index (I_geo) in the natural environment. Enrichment factor (EF) and geoaccumulation index (I_geo) results showed that Cr, Mn, Fe, Co, Zn, Y, Zr, Cd and U were significantly enriched, and Th was extremely enriched. The total content of REEs (ƩREEs) ranged from 101.3 to 12,911.3 µg g⁻¹, with an average 2431.1 µg g⁻¹ which was higher than the average crustal value of ΣREEs. A high concentration of Th and light REEs were strongly correlated, which confirmed soil enrichment with monazite minerals. High ratios of light REEs (LREEs)/heavy REEs (HREEs) with a strong negative Eu anomaly revealed a felsic origin. The comparison of the chondrite normalized REE patterns of soil with hinterland rocks such as granite, charnockite, khondalite and migmatite suggested that enhancement of trace and REEs are of natural origin.     

Retention behaviour of Cs(I), Sr(II), Tc(VII) and Np(V) on smectite-rich clay

The smectite-rich natural clay is being considered as a backfill and buffer material for Indian repository programme. In the present study, batch sorption measurements have been performed at trace concentrations for one of the minor actinide elements [Np(V)] and for the long lived fission products, Cs(I), Sr(II), and Tc(VII) on purified and conditioned smectite-rich clay at varying conditions of pH and ionic strength. In case of Cs(I) and Sr(II) the sorption was found to increase with pH. At any pH the sorption was found to decrease with increasing ionic strength of the suspension maintained with NaCl. Further, at any pH the sorption of Sr(II) is less than the corresponding value for Cs(I). This is indicative of effect of size selectivity on the sorption by the clay. Tc(VII), on the other hand, is poorly retained by the clay, which can be explained in terms of the negative charge on the TcO₄ ^? ion, which has negligible interaction with the predominantly negatively charged clay surface. In the case of Np(V), the sorption was found to increase albeit, slowly compared to Cs(I) and Sr(II) with pH, and it with no effect of ionic strength on the sorption at all pH values. This suggests that Np(V) primarily interacts with the surface sites via inner sphere complexation mechanism.     

Sorption of americium from low-level liquid wastes by nanocrystalline MnO2

Nanocrystalline MnO₂, synthesized by alcoholic hydrolysis of KMnO₄, has been studied as a sorbent for removal of americium from low level liquid waste solutions. The synthesized MnO₂ was found to have BET surface area of 230 m² g^?1. Am(III) was found to be sorbed by MnO₂ quantitatively within 15 min at pH 5. The sorption was found to be more than 90 % at as low a pH as 1.2 and reached to near 100 % at all pH values above pH 3.0 There was no effect of ionic strength (0.01–1.0 M NaCl, CaCl₂) on the sorption suggesting the sorption following inner sphere complexation mechanism at all the pH values. Adsorption isotherm studies were carried out using Eu(III) as a chemical analogue of Am(III). These studies showed the isotherm data to follow Langmuir adsorption isotherm.     

Coulometric determination of uranium in presence of iron/plutonium using a platinum working electrode

A controlled potential coulometric method for the determination of uranium in the presence of iron or plutonium using a platinum working electrode has been developed. The method consists of reduction of uranium in 8M H₂SO₄ by Ti(III) followed by destruction of excess Ti(III) and selective oxidation of Fe(II) or Pu(III) to Fe(III) or Pu(IV), respectively, by sodium nitrite. The U(IV) is subsequently determined by electrolytic oxidation at Pt electrode using Fe(III) as an intermediate. The method was employed for the determination of uranium in synthetic mixtures of U+Fe and U+Pu containing varying ratios of U/Fe or U/Pu. The precision obtained for uranium results was ±0.25%.     

Determination of neptunium using controlled potential coulometry

A method for controlled potential coulometric determination of neptunium by titration with internally electrolytically generated iron(II) has been developed. The method involves oxidation of Np to Np(VI) by Ce(IV), destruction of excess of Ce(IV) by NaNO₂ followed by determination of neptunium by reduction of Np(VI) to Np(IV) by internal generation of Fe(II). The method was employed for various neptunium solution samples and a precision of ±0.25% at 2–5 mg level of neptunium was obtained.     

Cascade synthesis of dihydrobenzofuran via Claisen rearrangement of allyl aryl ethers using FeCl3/MCM-41 catalyst

Dihydrobenzofuran as one of the active ingredients of the naturally occurring motif is synthesized by using in situ generation of ortho allyl phenols. Aryl allyl ethers on reacting with catalytic amounts of non noble metal iron (III) chloride supported on MCM-41 under moderate reaction conditions yield dihydrobenzofuran. First step via Claisen rearrangement gives ortho allyl phenol followed by its in situ cyclization to yield dihydrobenzofuran in very good yields. Both Lewis as well as Brønsted acidity of the catalyst as evidenced by Py-FTIR studies was found to catalyze the cascade synthesis of dihydrobenzofuran. The scope of the present strategy was successfully demonstrated for several substrates with varying electronic effects for the synthesis of corresponding dihydrobenzofuran with high yields in a range of 71–86%.     

Determination of uranium in presence of plutonium using differential spectrophotometry

The use of beams of heavy ions such as carbon, neon and argon for radiation therapy has the advantage that they have a very sharp Bragg maximum. When the Bragg peak coincide with the tumour location, it is possible to deposit the bulk of the energy of the ion in the region occupied by the malignancy. However, the concentration of ions and free radicals will be very high in the Bragg peak region which has not received the attention it deserves. So mutual recombination of these species will be very high. It is therefore necessary to assess the extent of these radical-radical recombinations at very high LET values. Spur diffusion model calculations have been made for high energy argon ions using water as a medium. For comparison, calculations have been done for proton tracks. It has been shown that in the Bragg peak region of argon ions even very high concentrations of scavengers have very little effect on radical-radical interactions. The implication is that when LET values are very high, practically all the radicals undegro recombination with each other. In order to explain the observed lethality of high LET radiation, it is suggested that the hydrogen peroxide formed also contribute to the killing of cells. In addition, the decomposition of H₂O₂ will contribute oxygen. This may be one of the reasons why high LET radiation shows strong lethality to hypoxic cells.