Isotope exchange of iodine between sodium iodide [Na131I] and [4-127I]iodoantipyrine via organic medium

The present investigation deals with a study of the isotope exchange reaction of iodine between sodium iodide [Na¹³¹I] and [4-¹²⁷I]iodoantipyrine in organic medium, using different iodinating radioiodine reagents of different carrier-iodine concentration. A maximum saturation yield over 90% of pure [4-¹³¹I]iodoantipyrine has been obtained by performing the isotope exchange reaction in ethanol at 80°C in 30 min. The same yield has been obtained using the same concentrations by performing the reaction at room temperature (17–20°C) for 3 h. Also the rate of the isotope exchange reaction was found to be carrier-iodine dependent as well as time and temperature dependent. According to these results and reaction conditions, a kit form method was elaborated for the synthesis of [4-¹³¹I]iodoantipyrine as well as [4-¹²³I]iodoantipyrine.     

Cross-coupling reactions of organosilicon compounds: new concepts and recent advances

This review highlights the rapid evolution of the newly-developed class of palladium-catalyzed cross-coupling reactions of organosilicon compounds. A myriad of heteroatom-containing silicon moieties (silyl hydrides, siletanes, silanols, silyl ethers, orthosiliconates, di- and polysiloxanes and pyridylsilanes) undergo mild and stereospecific cross-coupling. The diversity of methods for introduction of silicon groups into organic molecules and the range of organic electrophiles that can be used are emphasized.     

Solvent effects and correlation with Reichardt'sE T values on charge transfer spectra of bis(2,2′-bipyridyl)biscyanoiron(II)

The solvatochromic behaviour of biscyano-bis(2,2′-bipyridyl)iron(II) in a variety of solvents is described. The frequencies are correlated with Reichardt's solvent parameterE _T . Various trends are indicated, solvatochromic shifts of the title complex in various aqueous mixtures ofDMF and 2-butoxy ethanol are also reported.     

Thermodynamics of the extraction of Eu3+ with thenoyltrifluoroacetone,triphenylarsine oxide and other phosphine oxides

Extraction of Eu³⁺ from 0.1M aqueous perchlorate medium by thenoyltrifluoroacetone (HTTA) and by mixtures of HTTA and tributylphosphate (TBP), HTTA and triphenylphosphine oxide (TPPO), HTTA and trioctylphosphine oxide (TOPO) and HTTA and triphenylarsine oxide (TPAsO) has been studied at various temperatures allowing for the elucidation of the mechanism of extraction in each case and a comparison between the various bases.     

Studies on extraction of zirconium(IV) by tricapryl methyl ammonium chloride from sulphate media and its separation from hafnium(IV)

The distribution of Zr(IV) between aqueous H₂SO₄ solutions and organic phases of tricapryl methyl ammonium chloride has been described. The dependence of extraction on acidity, metal and solvent concentration, diluent type and temperature was thoroughly investigated. The possible extraction mechanism is discussed in the light of results obtained. A method for the separation of Hf(IV) from Zr(IV) is also suggested.     

Oxygen Microbubble Generator Enabled by Tunable Catalytic Microtubes

Rolled‐up catalytic Ti/Cr/Pt microtubes, consisting of inorganic nanomembranes integrated on‐chip, are used to generate oxygen microbubbles in solutions of hydrogen peroxide. Oxygen bubble parameters (frequency, radius and volumetric flow rate) are optimized at different concentrations of hydrogen peroxide and common dish soap. Increasing the aspect ratio of the microtube (e.g., tube length/diameter) leads to the formation of smaller bubbles, but at higher frequencies. Longer tubes produce less total oxygen volume in comparison to shorter tubes. We attribute this observation to the specific dynamic behaviours of bubbles in tubes.     

Powers of

We prove that the Cech-Stone remainder of the integers, , maps onto its square if and only if there is a nontrivial map between two of its different powers, finite or infinite. We also prove that every compact space that maps onto its own square maps onto its own countable infinite product.

     

Photorefractive half-adder: beam-fanning for optical generation of ‘SUM’ and ‘CARRY’

Optical implementation of an adder of arithmetic units that processes binary numbers is outlined. Dynamic range compression using biasing illumination in beam-fanning geometry as observed in a photorefractive BaTiO₃:Fe crystal forms the underlying principle of operation. By proper choice of polarization for two input signals, XOR and AND operations are realized. These two operations are essentially analogous to SUM and CARRY generation for binary addition. By providing shift (only in case of CARRY) and feedback, experimental results for half-adder are obtained. In addition, the technique forms a very simple way of implementing ‘original carries’ as required for full-adder. The geometry proposed is simple, energy-efficient and can be easily extended to multi-wavelength operations thus achieving spectral parallelism in optical domain.     

Luzin gaps

We isolate a class of ideals on that includes all analytic P-ideals and all ideals, and introduce `Luzin gaps' in their quotients. A dichotomy for Luzin gaps allows us to freeze gaps, and prove some gap preservation results. Most importantly, under PFA all isomorphisms between quotient algebras over these ideals have continuous liftings. This gives a partial confirmation to the author's rigidity conjecture for quotients . We also prove that the ideals and have the Radon-Nikodým property, and (using OCA) a uniformization result for -coherent families of continuous partial functions.

     

Two ideals

We find two ideals on neither of which is whose quotient Boolean algebras are homogeneous but nonisomorphic. This solves a problem of Just and Krawczyk (1984).