Inorganic ion-exchangers: Their role in chromatographic radionuclide generators for the decade 1993–2002

Ion-exchangers are found not only in water purification processes, the original major application, but also in analytical chemistry for the separation and isolation of elements, hydrometallurgy, inorganic chemistry and biochemistry, in food technology, and of course in many specialized fields related to the utilization of atomic energy. The use of organic ion-exchangers is limited by virtue of their limited stability under harsh conditions, whereas inorganic ion-exchangers possess important properties, which make them very useful for chemical separation and purification in intense radiation fields. The availability of short-lived radionuclides from radionuclide generators provides an inexpensive and convenient alternative to in-house radioisotope production facilities such as accelerators and cyclotrons. Due to their simplicity of operation, chromatographic based generators have been the method of choice, although generators based on solvent extraction and on volatization and sublimation have also been developed, and are routinely used. In this paper use of inorganic ion-exchangers for the development of radionuclide generators for the decade 1993–2002 has been compiled.     

Dual and tetraelectrode QCMs using imprinted polymers as receptors for ions and neutral analytes

Polymers as coating materials were combined with quartz crystal microbalances (QCMs) to design sensor devices for the detection of both ionic and neutral analytes in liquid phase. The design and geometry of dual and tetraelectrode QCMs have been optimized to reduce electric field interferences. An unusual Sauerbrey effect was observed while exposing potassium salt solution to 10- and 20-MHz QCMs, i.e. increase in the frequency shifts by a factor of seven, which is attributed to electro-acoustic phenomena. Non-functionalized sol-gel materials were synthesized by templating with hydrophobic salt such as tetraethyl ammonium picrate. Imprinting with these ions of low charge density leads to sensitive layers, and UV–Vis spectroscopy was used to check re-inclusion of this analyte. In the next strategy, functionalized polyurethane for potassium ions and sol-gel materials with aminopropyl group as ligand were generated to tune selectivity and sensitivity towards Ni²⁺ and Cu²⁺. Methacrylic acid polymers were optimized for the detection of atrazine by hydrogen bonding; double molecular imprinted polyurethane approach was followed for pyrene recognition. Finally, these imprinted polymers were combined with tetraelectrode QCM to develop sensor platform.     

2,3-Unsaturated allyl glycosides as glycosyl donors for selective α-glycosylation

In the presence of NBS and a catalytic amount of a Lewis acid, 2,3-unsaturated allyl glycosides [6-(allyloxy)-3,6-dihydro-2-(hydroxymethyl)-2H-pyran-3-ol] have been successfully used as versatile glycosyl donors for the stereoselective α-glycosylation of a variety of alcohols comprising sensitive functions such as acetonide, keto, nitro, and ester in 50-90% yields. The methodology offers an equally facile alternative to 4-pentenyl replacement in unsaturated sugars.     

Nano‐Ruby: A Promising Fluorescent Probe for Background‐Free Cellular Imaging

Bioprobes based on fluorescent ruby nanoparticles, which are suitable for ultrasensitive imaging, are reported. A stable aqueous/buffer colloid, permitting facile conjugation to proteins, is produced by femtosecond laser ablation of ruby and the nanoparticles (mean size 17 nm) are photostable, with long lifetime (1–4 ms) 694 nm emission. With time‐gating complete (>20 dB) suppression of cell autofluorescence and suppression of exogenous fluorophores is observed. Nanoparticles are imaged in as‐grown cells and those immunolabeled with quantum dots. Immunoassay binding to target biomolecules is also demonstrated.     

Formulation of a freeze-dried kit for 188Re-MAG3 and its quality control

The synthesis of ¹⁸⁸Re-MAG₃ is described using ¹⁸⁸Re, which was obtained from the alumina based ¹⁸⁸W/¹⁸⁸Re generator. Dependence of the radiolabeling yields of ¹⁸⁸Re-MAG₃ on reducing agent concentration, Bz-MAG₃ concentration, pH, temperature and incubation time was examined. In the case of optimum conditions the yield of ¹⁸⁸Re-MAG₃ was 98%. TLC and HPLC techniques were employed to monitor the different species formed. Biodistribution study of ¹⁸⁸Re-MAG₃ was carried out in rats and compared with behavior of ^99mTc-MAG₃.     

Crystallographic report: Chlorodimethyltin(IV) piperidine‐1‐carbodithioate

Me₂Sn(S₂CN(CH₂)₅)Cl contains five‐coordinated tin with a bidentate dithiocarbamate ligand spanning equatorial and axial positions in a distorted trigonal bipyramidal geometry. Copyright © 2005 John Wiley & Sons, Ltd.     

Ultrafast laser ablative generation of gold nanoparticles: the influence of pulse energy, repetition frequency and spot size

Previous studies investigating the role of the operating parameters on ultrafast laser ablative generation of gold nanoparticles have reported a wide range of nanoparticle size distribution and plasmon resonant properties. In some cases the reported role of fluence and other processing parameters is contradictory. In this systematic investigation, we deconstruct and examine the role of the component parts of fluence, namely pulse energy and ablation spot size, on nanoparticle generation. Other parameters such as exposure time and scan speed are also studied. We show that the nanoparticle average size and distribution is related to different contributions from pulse energy, pulse repetition frequency and spot size. We also correlate the average particle size and distribution with the wavelength and width of the plasmon resonance peak, and apply Mie theory in order to develop clearer physical insights into the mechanisms dominating nanoparticle generation.     

trans-cis Photoisomerization of a photoactive yellow protein model chromophore in crystalline phase

We have studied the photoinduced trans/cis isomerization of the protonated form of p-hydroxycinnamic thiophenyl ester, a model chromophore of the photoactive yellow protein (PYP), in crystalline phase, by both fluorescence and infrared spectroscopies. The conversion from trans to cis configuration is revealed by a shift of the fluorescence peak and by inspection of the infrared maker bands. The crystal packing apparently stabilizes the cis photoproduct, suggesting different environmental effects from the solvent molecules for this model chromophore in liquid solutions or from the amino acid residues for the PYP chromophore.     

Alternating groups as a quotient of $${{\varvec{PSL}}}\left( \mathbf{2}, \pmb {\mathbb {Z}} \left[ {{\varvec{i}}}\right] \right) $$

In this study, we developed an algorithm to find the homomorphisms of the Picard group \(\textit{PSL}(2,Z[i])\) into a finite group G. This algorithm is helpful to find a homomorphism (if it is possible) of the Picard group to any finite group of order less than 15! because of the limitations of the GAP and computer memory. Therefore, we obtain only five alternating groups \( A_{n}\), where \(n=5,6,9,13\) and 14 are quotients of the Picard group. In order to extend the degree of the alternating groups, we use coset diagrams as a tool. In the end, we prove our main result with the help of three diagrams which are used as building blocks and prove that, for \(n\equiv 1,5,6(\mathrm { mod}\, 8)\), all but finitely many alternating groups \(A_{n}\) can be obtained as quotients of the Picard group \(\textit{PSL}(2,Z[i])\). A code in Groups Algorithms Programming (GAP) is developed to perform the calculation.