Spectral band independent recognition in a differential binary joint transform correlator

Images of a target in a specific spectral band in general show no correlation with images of the same target in a different spectral band. Hence in a joint transform correlator (JTC) architecture, if the reference and input target are the images captured through a visible (e.g., charge-coupled device or CCD camera) and infrared (IR) detector, autocorrelation peaks are not obtained. This drawback has been overcome in this paper by the use of a CCD–IR fused image as the reference image. Daubechies wavelet transform, which produces the least root-mean-square (RMS) error in the fusion process in comparison to other wavelets, has been used for the purpose. A comparative analysis of the proposed idea has been carried out for the classical JTC (CJTC), binary JTC (BJTC) and differential binary JTC (DBJTC) algorithms. Since the DBJTC removes the dc completely and produces sharp correlation peaks compared to the other techniques, computer simulation and experimental results are shown for the proposed idea using DBJTC. The same fused reference image has also been used to identify multiple targets in a scene using DBJTC. Performance measures like correlation peak intensity (CPI), dc/ac and peak correlation energy (PCE) have been calculated as metrics of goodness for the proposed scheme.     

Synthesis of 2-amino-3-carbethoxy-1-hydroxyindoles

A general method is described for the synthesis of 2-amino-3-carbethoxy-l-hydroxyindoles by the reductive cyclization of 2-nitrophenylcyanoacetates using zinc and acetic acid at temperatures of 15–28°.     

Spectrophotometric studies of complexing equilibria of hafnium with some azo-dyes in aqueous solution

Hafnium forms three chelates 1:2 (M:L) (pH 1.0, 520 nm), 1:1 (pH 1.4, 520 nm), and 2:1 (pH 2.0, 520 nm) with PAR; and 1:2 chelate with EBB (pH 0.8, 590 nm), SVRS (pH 1.2, 560 nm), and CLM (0.25 M, 590 nm), respectively. In all the systems, only for 1:2 chelates, the exact nature of the equilibrium involved in chelation has been evaluated. The kinetic study and the number of protons liberated during chelation reaction have been studied. From the values of the equilibrium constant, the values of absolute stability constants for these complexes have also been evaluated.     

Absorptiometric study of the chelates formed between the lanthanoids and xylenol orange

Summary The formation of violet coloured chelates (_max=570 nm) between the lanthanoids and Xylenol Orange at p_H 5.5 is reported. Absorbance measurements indicate the composition of all the chelates to be 11 and the chelates are stable over p_H 4.0 to 7.0. The values of logK for various lanthanoid chelates of DCAC lie in the range of 4.5 to 5.4. The dissociation constants of Xylenol Orange have been evaluated and the position of the chelation has been suggested.

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Zusammenfassung Über die Bildung violett gefärbter Chelate (_max=570 nm) aus Lanthanoiden und Xylenolorange bei p_H 5,5 wurde berichtet. Absorptionsmessungen weisen in jedem Fall auf die Zusammensetzung 11 hin. Die Stabilität der Chelate ist zwischen p_H 4,0 und 7,0 gegeben. Der Logarithmus der Komplexkonstanten der verschiedenen Lanthanoidchelate mit Xylenolorange beträgt 4,5 bis 5,4. Die Dissoziationskonstanten von Xylenolorange wurden ermittelt und die Stellung des Chelatrings angegeben.

     

Invariom‐model refinement of l‐valinol

The structure of l ‐valinol [(S)‐(+)‐2‐amino‐3‐methyl­butan‐1‐ol or hydroxy­lated l ‐valine], C₅H₁₃NO, has been determined at 100 K by single‐crystal X‐ray diffraction. The independent atom model geometry, Flack parameter and figures of merit are compared with results from an invariom structure refinement. The latter provides H‐atom positions free of independent atom model bias and therefore yields a more accurate hydrogen‐bond pattern, and the geometry from invariom refinement shows an improved agreement with results from a quantum chemical geometry optimization.     

Activity and stability studies of ultrafine nanoencapsulated catalase and penicillinase

The enzymes catalase (bovine liver, EC 1.11.1.6) and -penicillinase (bacillus cereus strain 569, type I, EC 3.5.2.6) were successfully encapsulated in the polyacrylamide matrix. The encapsulation was carried out in the water pool of water/aerosol OT/n-hexane reverse micelles. The polymeric particles of encapsulated enzymes were reasonably monodisperse and had diameters in the range of several tens of nanometers as measured from quasi-elastic laser light scattering. The activity- pH profile of the encapsulated enzymes in buffer followed the same pattern as that of free enzymes. However, the encapsulated enzymes were found to be less active than their free forms. The enzymes in the encapsulated form were more stable (both thermal stability and shelf-life) as compared to free enzymes. The activity of the encapsulated enzymes was found to be dependent on the degree of cross-linking of the polymer matrix. The greater the cross-linking in the matrix, the lesser were the activity of the encapsulated enzyme.     

Raman spectroscopic characterisations and analytical discrimination between caffeine and demethylated analogues of pharmaceutical relevance

The FT Raman spectrum of caffeine was analysed along with that of its demethylated analogues, theobromine and theophylline. The similar but not identical structures of these three compounds allowed a more detailed assignment of the Raman bands. Noticeable differences in the Raman spectra of these compounds were apparent and key marker bands have been identified for the spectroscopic identification of these three compounds.     

Analysis of thermogravimetric data for some coordination polymers of zinc(II) and cadmium (II)

A detaliled thermal study on some new Zn(II) and Cd(II) coordination polymers with substituted biurat such as sebacyl bis-biurat (SBBU), adipyl bis-biurat (ABBU) and fumaryl bis-biurat (FBBU) is being reported. Freeman-Carroll and Sharp-Wentworth methods have been used to calculate activation energy and thermal stability of these polymers. Kinetic parameters have been calculated using the data of Freeman Carroll method. The results obtained have been suitably discussed.

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Zusammenfassung Es wird über eine ausführliche Untersuchung einiger neuer Zn(II)- und Cd(II)- Koordinationspolymere mit substituiertem Hydrogenurat, wie z.B. Sebacyl-bis-hydrogenurat (SBBU), Adipyl-bis-hydrogenurat (ABBU) und Fumaryl-bis-hydrogenurat (FBBU) berichtet. Zur Berechnung der Aktivierungsenergie und der thermischen Stabilität dieser Polymere wurde das Freeman-Carroll und das Sharp-Wentworth-Verfahren angewendet. Unter Anwendung der Daten des Freeman Carroll Verfahrens wurden kinetische Parameter berechnet. Die erhaltenen Ergebnisse wurden angemessen diskutiert.

     

Extraction of U(VI), Pu(IV), Am(III) and some fission products by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester immobilized polyvinyl alcohol hydrogels

Cross-linked hydrogel matrices immobilized with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HA), were prepared to investigate their application in the recovery of radionuclide from acidic waste solutions. Gamma-radiation was used to produce HA immobilized polyvinyl alcohol (PVA) hydrogels (HA-gel). The hydrogels with different characteristics such as: degree of cross-linking (by varying radiation dose) and quantity of extractant immobilized (by starting with aqueous PVA solution containing different amounts of HA), were synthesised. These HA-gels were investigated for solid-liquid phase extraction of U(VI), Pu(IV), Am(III) and some fission products, under various experimental conditions. The concentration of HNO₃ in the aqueous phase was found to play an important role in the extraction of these radionuclei. Extraction of U(VI) was more favourable at lower concentration of HNO₃ (∼0.001 to 0.5M), while at higher concentrations (∼0.5 to 3M HNO₃), more than 90% of Pu(IV) present in the aqueous phase, could be extracted by the HA-gel. The extraction of Am(III) was also found predominant only at lower acidities (at pH∼2 and above). Under optimized conditions, maximum metal loading capacities obtained were 19±0.8 mg, 8±0.4 mg and 11±0.5 mg per gram of swollen HA-gel, for U(VI), Pu(IV) and Am(III), respectively. Under the experimental conditions, extractions of Cs(I) and Sr(II) were observed to be negligible. No leaching out of HA from the HA-gel particles was noted even after its repetitive use for the studied ten cycles of extraction and stripping experiments, as evident from its unchanged extraction efficiency.     

IRMPD Action Spectroscopy,ER-CID Experiments,and Theoretical Studies of Sodium Cationized Thymidine and 5-Methyluridine: Kinetic Trapping During the ESI Desolvation Process Preserves the Solution Structure of [Thd+Na]<Superscript>+</Superscript>

Thymidine (dThd) is a fundamental building block of DNA nucleic acids, whereas 5-methyluridine (Thd) is a common modified nucleoside found in tRNA. In order to determine the conformations of the sodium cationized thymine nucleosides [dThd+Na]⁺ and [Thd+Na]⁺ produced by electrospray ionization, their infrared multiple photon dissociation (IRMPD) action spectra are measured. Complementary electronic structure calculations are performed to determine the stable low-energy conformations of these complexes. Geometry optimizations and frequency analyses are performed at the B3LYP/6-311+G(d,p) level of theory, whereas energies are calculated at the B3LYP/6-311+G(2d,2p) level of theory. As protonation preferentially stabilizes minor tautomers of dThd and Thd, tautomerization facilitated by Na⁺ binding is also considered. Comparisons of the measured IRMPD and computed IR spectra find that [dThd+Na]⁺ prefers tridentate (O2,O4',O5') coordination to the canonical 2,4-diketo form of dThd with thymine in a syn orientation. In contrast, [Thd+Na]⁺ prefers bidentate (O2,O2') coordination to the canonical 2,4-diketo tautomer of Thd with thymine in an anti orientation. Although 2,4-dihydroxy tautomers and O2 protonated thymine nucleosides coexist in the gas phase, no evidence for minor tautomers is observed for the sodium cationized species. Consistent with experimental observations, the computational results confirm that the sodium cationized thymine nucleosides exhibit a strong preference for the canonical form of the thymine nucleobase. Survival yield analyses based on energy-resolved collision-induced dissociation (ER-CID) experiments suggest that the relative stabilities of protonated and sodium cationized dThd and Thd follow the order [dThd+H]⁺ < [Thd+H]⁺ < [dThd+Na]⁺ < [Thd+Na]⁺.

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