Screening of domperidone in wastewater by high performance liquid chromatography and solid phase extraction methods

Domperidone is a dopamine D₂ receptor antogonist, which has been used as antiemetic agent in human beings. It has been found in wastewater released by some pharmaceutical industries leading to the contamination of surface and ground water. Therefore, a sensitive, inexpensive and reproducible HPLC-SPE method was developed for the analysis of domperidone in the wastewater. The column used was Waters symmetry C₁₈ (15 cm × 0.46 mm, 5 μm). The mobile phase used was phosphate buffer (50 mM, pH 3.5) acetonitrile (80:20, v/v) at the flow rate 2.0 mL/min. The detection was achieved by using UV mode at 230 nm. The retention, separation and resolution factors were 2.63, 3.00 and 3.20, respectively. The percentage recovery of domperidone from wastewater was 95.0%. Celiprolol was used as the internal standard to access the percentage extraction of domperidone from wastewater.     

铜纳米阵列高效电解水产氧催化剂的制备

本文报道了一种利用简单的两步牺牲模板法,在泡沫铜基底表面完成了三维氧化铜纳米晶阵列的生长. 氧化铜纳米晶阵列具有良好的导电性,稳定性,在碱性溶液中有着优秀的电解水产氧催化性能. 氧化铜纳米晶阵列催化水的电化学氧化只需400 mV的过电势即可达到100 mA/cm²的电流密度,与其它铜基电解水产氧催化剂以及贵金属IrO₂相比都有着明显的优势. 氧化铜纳米晶阵列在270 mA/cm²左右的工作电流下连续工作10 h依然可以保持良好的稳定性,是相同的工作电压下IrO₂工作电流的10倍(约25 mA/cm²).     

Chiral resolution of multichiral center racemates by different modalities of chromatography

It is a continuous chase of researchers to separate chiral racemates due to their dominance in the pharmaceutical industry, agrochemicals, and food additives. There are many analytical techniques which have been used to resolve one chiral center racemates, but, little the literature report is scanty for the resolution of multiple stereogenic center racemates. Therefore, in this article the efforts were made to describe the enantiomeric resolution of multiple stereogenic center racemates by different modalities of chromatography. The various modalities discussed are high-performance liquid chromatography, capillary electrophoretic chromatography, miceller electrokinetic chromatography, supercritical fluid chromatography, nanoliquid chromatography, and gas chromatography. Besides, the attempts have also been made to discuss the future challenges and prospectives of the enantiomeric resolution of multichiral racemates.     

Intelligent reversible watermarking technique in medical images using GA and PSO

The advances in recording, editing, and broadcasting multimedia contents in digital form motivate to protect these digital contents from illegal use, such as duplication, manipulation, and redistribution. However, watermarking algorithms are designed to satisfy requirements of applications, as different applications have different concerns. We intend to design a watermarking algorithm for applications which require high embedding capacity and imperceptibility, to maintain the integrity of the host signal as well as embedded information. Reversible watermarking is a promising technique which satisfies our requirements. In this paper, we concentrate on improving the watermark capacity and reducing the perceptual degradation of an image. We investigated the Luo's [1] additive interpolation-error expansion algorithm and enhanced it by incorporating with two intelligent techniques: genetic algorithm (GA), and particle swarm optimization (PSO). Genetic algorithm is applied to exploit the correlation of image pixel values to obtain better estimation of neighboring pixel values, which results in optimal balance between information storage capacity and imperceptibility. Particle swarm optimization (intelligent technique) is also applied for the same purpose. Experimental results show that PSO and GA nearly give the same results, but GA outperforms the PSO. Experimental results also reveal that the proposed strategy outperforms the state of art works in terms of perceptual quality and watermarking payload.     

Simultaneous quantification of five marker compounds of Betula utilis stem bark using a validated high-performance thin-layer chromatography method

A sensitive, selective and robust densitometric high-performance thin-layer chromatographic method was developed and validated for five marker compounds, namely betulin, lupeol, oleanolic acid, 3-acetyloleanolic acid and β-sitosterol, known for their various therapeutic activities. The marker compounds have been isolated from the stem bark of Betula utilis, well characterized by the spectral analysis, and their simultaneous quantitative determination carried out by high-performance thin-layer chromatography (HPTLC) method. The resolution of marker compounds was carried out on silica-gel 60 plates, using n-hexane:ethyl acetate (8:2 v/v) as the mobile phase. The HPTLC densitometry was performed at 500-nm wavelength after the post chromatographic derivatization with ceric ammonium sulfate reagent. The optimized method provided good linear relation (r>0.9960) for all the investigated analytes. The method is simple, and reproducible, which may be applied for quantitative analysis of the above-mentioned marker compounds.     

Synthesis of highly fluorescent and water soluble perylene bisimide

Designed and synthesized a new highly water soluble N,N¹-bis（2-（（5-（（dimethylamino）methyl）furan-2-yl）methylthio）ethyl）-perylene -3,4,9,10-tetracarboxylic diimide from 2-（（5-（（dimethylamino）methyl）furan-2-yl）methylthio）ethanamine and perylene-3,4,9,10- tetracarboxylic dianhydride.The compound was characterized by ¹H,¹³C,2D NMR,mass and IR techniques.The compound is highly fluorescent with good solubility in water and other polar solvents.     

α-MoO3 nanowire-based amperometric biosensor for l-lactate detection

Large-scale orthorhombic single-crystalline molybdenum trioxide nanowires were synthesized using a facile one-pot hydrothermal method. Lactate oxidase enzyme was immobilized on the nanowires to produce a highly sensitive electrochemical biosensor for l-lactate detection. At an applied potential of 0.5 V, the sensor exhibited a high sensitivity of 0.87 μA/mM with a fast response to l-lactate (90% of response times within 10 s). A linear response was obtained over a concentration range from 0.5 to 8 mM with a detection limit of 0.15 mM (S/N?=?3). The developed biosensor showed excellent reproducibility and operational stability, as well as the ability to be stored long term.     

Photodynamic effect in near-IR light by a photocytotoxic iron(III) cellular imaging agent

A red light for cancer cells: an iron(III) complex (1, see picture) that contains an anthracenyl fluorophore moiety and a catecholate ligand is a potent, metal-based PDT agent that efficiently photocleaves DNA in near-infrared light, has significant nuclear uptake, and high photocytotoxicity in red light by an apoptotic pathway in HeLa and MCF-7 cancer cells.     

Influence of rare earth Ce on structural, electrical and magnetic properties of Sr based W-type hexagonal ferrites

A series of single phase W-type Sr_3−xCe_xFe₁₆O₂₇ (x=0, 0.02, 0.04, 0.06, 0.08, 0.10) hexagonal ferrites prepared by the Sol-Gel method was sintered at 1050 °C for 5 h. The X-ray diffraction analysis reveals that all the samples belong to the family of W-type hexagonal ferrites. The c/a ratio falls in the range of W-type hexagonal ferrites. The grain size was measured by SEM varies from 0.7684 to 0.4366 μm which shows that the Ce³⁺ substituted samples have smaller grain size than pure ferrite Sr₃Fe₁₆O₂₇ which results from the difference in ionic radii of Ce³⁺ (1.034 Å) and Sr²⁺ (1.12 Å). The room temperature resistivity of the present samples varies from 6.5×10⁸ to 272×10⁸ Ω-cm. The coercivity increases from 1370 to 1993 Oe which is consistent with the decrease in grain size. The coercivity values indicate that the present samples fall in the range of hard ferrites. The large value of H_c may be due to domain wall pinning at the grain boundaries.     

Experimental Study on Powder Flowability Using Vibration Shear Tube Method

The flowability of powders with different mass median diameters ranging from micrometers to nanometers was measured using the vibration shear tube method. In the measurement system used in this study, the powder was discharged through a narrow gap between a vibrating tube edge and a flat bottom surface, where each particle could experience high shear forces to overcome the adhesion and friction forces. The vibration amplitude was increased during the measurement, and the mass of particles discharged was measured at constant time intervals. From the relationship between the mass flow rate and the vibration acceleration, static and dynamic properties of the powders were evaluated using the critical vibration acceleration, characteristic mass flow rate, and gradient of mass flow rate. The correlation between the static and dynamic properties was studied in detail.