Analysis of formose sugar and formaldehyde by high-performance liquid chromatography

Formose sugar and formaldehyde (HCHO) were analyzed using high-performance liquid chromatography (HPLC) utilizing a CarboPac PA1 column (Dionex) and pulsed amperometric detection. This HPLC system was unsuitable for the analysis of formose sugar and HCHO and thus reducing sugars and unconverted HCHO were determined by endowing them with charges through a derivatization method using 2,4-dinitrophenylhydrazine. The separation and detection of compounds were performed by three Chromolith RP-C18 columns (Merck) and diode array detection, at a wavelength of 360 nm ultraviolet light, respectively. Lower sugars (except HCHO) showed some instabilities when the derivatized samples were kept for the extended periods of time. For C₅ and consecutive higher sugars, a certain derivatization time was necessary. In the present case (formose reaction with partial HCHO conversion), approximately 18 h may be a reasonable compromise for the derivatization reaction. A derivatization agent to compound mole ratio of up to 100:1 was required to complete the derivatization of C₄ and higher sugars. However, the analysis of C₄ and consecutive higher sugars is problematic for example due to overlapping of peaks or branched-chain sugars.     

Synthesis, crystal structure and in vitro antitumor activity of carboxylate bridged dinuclear organotin(IV) complexes

Two novel dinuclear organotin(IV) complexes [n-Bu₂Sn(imda)(H₂O)]₂·Bipy (1) and [n-Bu₂Sn(imda)(H₂O)]₂·Phen (2) [H₂imda = iminodiacetic acid, Bipy = 2,2′-bipyridine and Phen = 1,10-phenanthroline] were synthesised and characterized employing IR, ¹H, ¹³C, ¹¹⁹Sn NMR, and ¹¹⁹Sn Mössbauer spectroscopic and elemental analyses. Single crystal X-ray crystallography of 1 has confirmed that it is a binuclear Sn(IV) species formed via carboxylate bridges where each metal adopted a seven coordinate distorted pentagonal bipyramidal geometry. The iminodiacetate dianion (imda²⁻) acts as a potential tridentate [N,O,O] carboxylate bridging ligand. The packing revealed that the additional α-diimine (Bipy or Phen) does not coordinate to metal ion. However, its presence in the crystal lattice as spacer helps for the formation of a supramolecular framework by bringing the two binuclear species close enough through extensive H-bonding. The in vitro cytotoxicity of compounds 1 and 2 indicate better results than cisplatin against three tumor cell lines investigated.     

Fission studies of gold induced by (1665 MeV) π- using a CR-39 detector

The fission cross section and fission probability of ¹⁹⁷Au, induced by (1665 MeV) π^-, have been studied using CR-39 track detectors. A 4π-geometry was used to count track statistics. A beam of negative pions of 1665 MeV was produced at AGS of Brookhaven National Laboratory, USA, and allowed to fall normally on the stack. Two detectors from the stack were scanned for fission fragment tracks after etching in 6N NaOH at 70℃. The statistics of fission fragment tracks in both detectors were obtained. It was found that there was a marked asymmetry of registered tracks with respect to the forward and backward hemispheres. This asymmetry could be partly accounted for on the basis of momentum transfer to the struck nucleus. On the basis of counting statistics fission cross section was measured, and fission probability was determined by dividing the fission cross section with the reaction cross section. The fission cross-section and fission probability were compared with the computed values using the cascade-exciton model code CEM95.     

Four-dimensional parameter estimation of plane waves using swarming intelligence

This paper proposes an efficient approach for four-dimensional(4D) parameter estimation of plane waves impinging on a 2-L shape array. The 4D parameters include amplitude, frequency and the two-dimensional(2D) direction of arrival,namely, azimuth and elevation angles. The proposed approach is based on memetic computation, in which the global optimizer, particle swarm optimization is hybridized with a rapid local search technique, pattern search. For this purpose,a new multi-objective fitness function is used. This fitness function is the combination of mean square error and the correlation between the normalized desired and estimated vectors. The proposed hybrid scheme is not only compared with individual performances of particle swarm optimization and pattern search, but also with the performance of the hybrid genetic algorithm and that of the traditional approach. A large number of Monte–Carlo simulations are carried out to validate the performance of the proposed scheme. It gives promising results in terms of estimation accuracy, convergence rate, proximity effect and robustness against noise.     

Vibration characteristics of FGM circular cylindrical shells filled with fluid using wave propagation approach

The vibration characteristics of a functionally graded material circular cylindrical shell filled with fluid are examined with a wave propagation approach. The shell is filled with an incompressible non-viscous fluid. Axial modal dependence is approximated by exponential functions. A theoretical study of shell vibration frequencies is analyzed for simply supported-simply supported, clamped-simply supported, and clamped-clamped boundary conditions with the fluid effect. The validity and the accuracy of the present method are confirmed by comparing the present results with those available in the literature. Good agreement is observed between the two sets of results.     

Development,In-Vitro Characterization and Preclinical Evaluation of Esomeprazole-Encapsulated Proniosomal Formulation for the Enhancement of Anti-Ulcer Activity

Objective: The present study aimed to develop and optimize esomeprazole loaded proniosomes (EZL-PNs) to improve bioavailability and therapeutic efficacy. Method: EZL-PNs formulation was developed by slurry method and optimized by 33 box-Bhekhen statistical design software. Span 60 (surfactant), cholesterol, EZL concentration were taken as independent variables and their effects were evaluated on vesicle size (nm), entrapment efficiency (%, EE) and drug release (%, DR). Furthermore, optimized EZL-PNs (EZL-PNs-opt) formulation was evaluated for ex vivo permeation, pharmacokinetic and ulcer protection activity. Result: The EZL-PNs-opt formulation showed 616 ± 13.21 nm of vesicle size, and 81.21 ± 2.35% of EE. EZL-PNs-opt exhibited negative zeta potential and spherical confirmed scanning electron microscopy. EZL-PNs-opt showed sustained release of EZL (95.07 ± 2.10% in 12 h) than pure EZL dispersion. The ex-vivo gut permeation result exhibited a significantly (p < 0.05) enhanced flux than pure EZL. The in vivo results revealed 4.02-fold enhancement in bioavailability and 61.65% protection in ulcer than pure EZL dispersion (43.82%). Conclusion: Our findings revealed that EZL-PNs formulation could be an alternative delivery system of EZL to enhance oral bioavailability and antiulcer activity.     

Physical vapor deposition of SnS:PbS-dithiocarbamate chalcogenide semiconductor thin films: elucidation of optoelectronic and electrochemical features

Abstract

This work reports the first investigation on the physical vapor deposition of thin films of tin sulfide doped lead sulfide (SnS:PbS). In-situ synthesis route using diethyldithiocarbamate (DTC) ligand was adopted for SnS-DTC, PbS-DTC and SnS:PbS-DTC complex formation. PbS-DTC and SnS:PbS-DTC expressed an average crystallite size of 30.98 and 29.74?nm, respectively shown by X-ray diffraction (XRD) analysis. A face centered cubic geometry was revealed from XRD. Ultraviolet visible spectrophotometry expressed a direct and indirect band gap of 3.4 and 3.2?eV, respectively for SnS:PbS-DTC. A smooth morphology with presence of larger agglomerated particles was disclosed by scanning electron microscopy for SnS:PbS-DTC thin films with 615?nm thickness. SnS:PbS-DTC thin films expressed remarkable electrochemical behavior explored via cyclic voltammetry, linear sweep voltammetry and chronoamperometry showing an improvement in the photo-current response upon potential bias increment. The results of the current research indicated the potential of SnS:PbS-DTC thin films for utilization in different types of photovoltaic devices.     

Double sequential fission in the reaction (16.7 MeV/u) U + Au observed with mica detectors

One of the main advantages of using dielectric track detectors in the study of heavy ion interactions is the possibility of observing each multi-prong event individually with complete kinematical details. It is thus possible to analyze even those reaction channels that have very low branching ratios. In the study of reactions induced by 16.7 MeV/u uranium ions incident on natural gold targets, we have observed 18 four-pronged events in a total detector area of 24 cm². Using a polynomial range-energy relationship, empirically fitted to the observed data of binary and ternary events, it was possible to perform kinematical analysis of 10 out of 18 events. The masses and relative velocities of the reaction products, determined in this analysis were compared with theoretical prediction based on double sequential fission process. An agreement within one standard deviation with respect to theoretical values has been found for eight analysed events.     

Spin-2—on-line low temperature nuclear orientation facility at YASNAPP-2 complex in Jinr Dubna

The Spin-2 facility built at YASNAPP-2 experimental complex of the Joint Institute of Nuclear Research is described. The basic parameters of SPIN-2 and YASNAPP-2 are discussed.     

Reactions ofN-trimethylsilyl-imidazole and-2-methylimidazole with anhydrous CoCl2 and [Co(Ph3P)2Cl2]; synthesis and physicochemical studies on two-coordinate cobalt(II) complexes

Summary Reactions ofN-trimethylsilylimidazole andN-trimethyl-silyl-2-methylimidazole with CoCl₂ yield chloro(imidazolato)cobalt(II), (1), or chloro(2-methylimidazolato)-cobalt(II), (2). However, the corresponding reactions of [Co(Ph₃P)₂Cl₂] cause total removal of Ph₃P along with the substitution of both the chlorine atoms yielding bis(imidazolato)cobalt(II), (3), or bis(2-methylimidazolato)cobalt(II), (4), in the form of light blue microcrystalline solids. The complexes have been characterized by elemental analysis, molecular weight, and magnetic susceptibility measurements, and i.r., reflectance and electronic spectra. The results are consistent with formulations as rare examples of two-coordinate cobalt(II) derivatives.Author to whom all correspondence should be directed