NMR AND DFT STUDY OF Co-C BOND ACTIVATION MECHANISM IN VITAMIN B_(12) COMPOUNDS

This report focuses on a theoretical study of the cobalt-cabon bond activation mechanism in Vitamin B12, its co enzyme complexes, and model compounds such as cobalamins (Cbl), cobaloximes and cobalt porphyrins. In particular, emphasis is placed on the nucleotide loop and its role in the base on and base off mechanism.     

Electroninitiated polymerization of bis(trichlorophenoxo)-tetramethylethylene diamine copper(II)

Electroninitiated polymerization of bis(trichlorophenoxo)-N,N,N′,N′-tetramethylethylene diamine copper(II) was achieved in acetonitrile at various peak potentials of the monomer. A constant potential approach was selected in polymerization reactions. Electrolyses were carried out under air, nitrogen, and oxygen atmospheres. Structural analyses of the polymers were done by ¹H-NMR and ¹³C-NMR FT–IR spectroscopy. Molecular weights of the polymers were determined by vapor pressure (isopiestic) method.     

MALDI-MS of drugs: Profiling,imaging, and steps towards quantitative analysis

Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique which can be used in mass spectrometry to produce ions from biomolecules without inducing the fragmentation associated with traditional methods of ionization. When used with small molecules, the lack of fragmentation allows identification of specific molecules against a background of alternative signals; thus, for example, the presence of drug molecules and metabolites can be distinguished from a range of alternative biomolecules present within a tissue sample. Using highly collimated lasers in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) allows imaging of a tissue sample whereby the laser is rastered across the sample and individual mass spectra are collected in a serial manner. Thus, the distribution of the molecules within the tissue sample can be presented in the form of a 2D image. While the detection of specific drug molecules and metabolites within biological samples has its uses, quantification of those same molecules would be of greater benefit in a clinical setting. However, accurate quantification presents additional challenges. We present an overview of the MALDI-MS technique followed by recent progress in profiling drugs and their metabolites through imaging drug distributions within tissues and finish with recent developments in the quantification of drugs in tissues by MALDI-MSI.     

Biological screening of some Turkish medicinal plant extracts for antimicrobial and toxicity activities

Screening of antibacterial activity and toxicity of 22 aqueous plant extracts from 17 Turkish plants was conducted. Antibacterial activity was performed with six bacteria including Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and Staphylococcus epidermidis. Extracts of Tussilago farfara leaves, Helichyrsum plicatum flowers, Solanum dulcamara aerial parts and Urtica dioica leaves gave the best inhibitory activity against S. pyogenes, S. aureus and S. epidermidis. Of the 22 plant extracts, 20 extracts displayed toxicity (LC50 was <1000 mg L(-1)) in the brine shrimp bioassay. For radish seed bioassay, two different determinations (root length and seed germination) were performed with a comparison between two concentrations (50,000 mg L(-1) and 10,000 mg L(-1)). At low concentration (10,000 mg L(-1)), S. dulcamara aerial parts and Primula vulgaris leaf extracts were observed to inhibit the root length more than the other plant extracts. Also, the most inhibitive plant extract for seed germination was obtained with S. dulcamara aerial parts.     

NO在Er2O3/Bi2O3催化剂上的程序升温分解

NOx是造成大气污染的化学物质之一,因此,消除NOx是环境保护的一项重要任务,目前比较成熟的消除NOx工艺是用氨为还原剂和V2O5/TiO2为催化剂的选择催化还原(SCR)法[1],但其成本过高.     

原料气中添加CO对CO_2在铜基催化剂上加氢反应的促进作用(英文)

研究了CO2在Cu－Zn－Al催化剂上的加氢合成甲醇反应。发现在原料气中添加少量的CO可提高甲醇的选择性和收率。TPD和TPSR结果表明,CO占据催化剂表面部分活性位并抑制CO2的逆水煤气转换,促进了甲醇的生成。     

Rh多晶表面CO2还原过程的电化学和原位FTIR反射光谱研究

应用程序电位扫描法和电化学原位FTIR反射光谱从定量角度在分子水平 上研究了CO2在Rh电极上的电催化还原性能。红外光谱结果指出CO2还原的吸附产物为线型和桥式吸附态CO物种。在所研究和还原电位范围（－0．15－0．40V）和相同还原时间,CO2还原吸附物种的氧化电量随还原电位的负移而增大,在每个还原电位下,时间超过250s时都可达到一个相应的饱和值。原位红外光谱和电化学研究结果表明,CO2的还原与Rh电极表面氢吸附反应密切相关,同时需要一定数量相邻表面位的参与。因此生成的CO不能在Rh电极表面达到满单层吸附,而是形成均匀的亚单层分布。     

Multilevel Deep Feature Generation Framework for Automated Detection of Retinal Abnormalities Using OCT Images

Optical coherence tomography (OCT) images coupled with many learning techniques have been developed to diagnose retinal disorders. This work aims to develop a novel framework for extracting deep features from 18 pre-trained convolutional neural networks (CNN) and to attain high performance using OCT images. In this work, we have developed a new framework for automated detection of retinal disorders using transfer learning. This model consists of three phases: deep fused and multilevel feature extraction, using 18 pre-trained networks and tent maximal pooling, feature selection with ReliefF, and classification using the optimized classifier. The novelty of this proposed framework is the feature generation using widely used CNNs and to select the most suitable features for classification. The extracted features using our proposed intelligent feature extractor are fed to iterative ReliefF (IRF) to automatically select the best feature vector. The quadratic support vector machine (QSVM) is utilized as a classifier in this work. We have developed our model using two public OCT image datasets, and they are named database 1 (DB1) and database 2 (DB2). The proposed framework can attain 97.40% and 100% classification accuracies using the two OCT datasets, DB1 and DB2, respectively. These results illustrate the success of our model.     

10 ps High Power Laser System at 248 nm

A simple 10 ps KrF laser system consisting of quenched dye laser oscillator pumped by a XeCl laser, a distributed feedback dye laser (DFDL), a three-stage dye amplifier and a two-stage KrF amplifier are described. The output of the laser system is 140 mJ with 10 ps pulse width by using polarization-multiplexing amplification. A focused output laser intensity of about 4×1015 W/cm2 is obtained. The saturation fluence for KrF laser is obtained with this laser.     

A GROUP OF EXACT (3+1) DIMENSIONAL CYLINDRICALLY SYMMETRIC WAVE SOLUTIONS TO THE EINSTEIN GRAVITATIONAL FIELD EQUATION

Starting with the diagonal spacetime metric tensor, the Einstein gravitational field equation is solved, and a set of exact (3+1) dimensional cylindrically symmetric wave solutions with two arbitrary functions are found. In these solutions all nonvanishing components of spacetime metric tensor are varying with the same propagating factor (ct-z) while the waves are travelling along z axis. The physical picture and the condition of positive energy density of the wave solutions are discussed.