Synthesis of 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-N-methylhydrazino-2,1,3-benzoxadiazole (DAABD-MHz) as a derivatization reagent for aldehydes in liquid chromatography/electrospray ionization-tandem mass spectrometry

Benzofurazan derivatization reagent, 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-N-methylhydrazino-2,1,3-benzoxadiazole (DAABD-MHz), for aldehydes in liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS), was synthesized. DAABD-MHz reacted with aliphatic aldehydes under mild conditions. The generated derivatives were separated on a reversed-phase column and detected by ESI-MS/MS with detection limits of 30-60 fmol on-column. Upon collision-induced dissociation, a single and intense fragment ion at m/z 151 was observed. These results suggested that DAABD-MHz was suitable as a derivatization reagent in LC/ESI-MS/MS.     

Synthesis,characterization of V2O5 nanoparticles and determination of catalase mimetic activity by new colorimetric method

Journal of Thermal Analysis and Calorimetry - This paper deals with an advanced colorimetric method used to determine the catalase mimetic activity of V2O5 nanoparticles by measuring the decrease...     

Differential optical absorption spectroscopy-based refractive index sensor for cancer cell detection

Optical Review - A novel spectroscopic optical sensor is presented for cancerous cell detection in various parts of the human body (i.e., cervix, adrenal gland, breast, skin, and blood). An...     

Determination of lawsone in henna powders by high performance thin layer chromatography

The lawsone content has been evaluated quantitatively in eight commercial henna powders and two collected henna leaves. The phenolic, chloroform-soluble fraction of the majority of the examined samples showed the presence of lawsone and two other pigments. Here we aimed to optimize high performance thin layer chromatography for the determination of lawsone. Upon using the optimized method the examined samples showed considerable variation in lawsone concentration ranging from 0.004 up to 0.608 wt%, indicating that some samples were almost devoid of lawsone. Some of these products were subjected to preliminary in vivo toxicity studies.     

多相CeO2催化剂上氧化吲哚与醛的选择性C3烯基化反应

本文报道了将市售CeO2作为一种高活性和可重复使用的催化剂用于无溶剂条件下氧化吲哚与醛的C3选择性烷基化反应.这种催化方法一般适用于不同的芳香族和脂肪族醛,得到3-烷基二烯-辛醇,产率高(87%–99%),立体选择性高(79%–93%为E-异构体).这是从氧化吲哚与各种脂肪族醛催化合成3-烯基氧化吲哚的首例.采用原位红外光谱研究了CeO2上Lewis酸位点与苯甲醛之间的Lewis酸-碱相互作用.不同粒径CeO2催化剂的构效关系研究表明,无缺陷CeO2表面是该反应的活性中心.     

Congeneric lantibiotics from ribosomal in vivo peptide synthesis with noncanonical amino acids

Expanded repetoire: Synthetic amino acids translated into propeptides dramatically increase the chemical diversity of the two-component lantibiotic lichenicidin. This opens new routes towards novel and unique peptide antibiotic sequences, which could display features important for medical applications.     

Stability of neutral and negative donor impurity in a semiconductor cylindrical quantum dot

The stability of neutral (D⁰) and negative charged donor (D⁻) on- and off-center in anisotropic cylindrical quantum dot (CQD) is studied by use of a variational approach. Two-parameter anisotropic trial wave function which includes electron-correlation effects is utilized, to explore strong and weak confinement regions. A comparison between one and two-parameter trial wave functions results is introduced. The finite barrier height and the CQD dimensions, dependence of the “stability and the binding energy” of the D⁰ and the D⁻ is obtained. It has been shown that the donor's stability dependent on CQD dimensions and the confinement potential in strong confinement region but in weak confinement region, the stability of D⁰ and D⁻ is dependent strongly on the quantum dot (QD) radius R. It has been found that the donors D⁰ and D⁻ off-center are less stable than the on-center impurities, and also the off-center donors more stable in small CQDs. It has shown that the stability of D⁻ depends on the energy of the excess electron.     

Physical Clogging of Uniformly Graded Porous Media Under Constant Flow rates

This study investigated the physical clogging of uniformly graded porous media under constant flow rates using natural porous media and suspensions. The porous media selected for this experimental study was a fine-to-medium sandy soil fractioned into thirteen uniformly graded beds: seven unisize beds and six uniform beds. The physical clogging of the beds was studied using two types of silt suspensions as along with two suspension concentrations and three water discharges. It was found that the permeability reduction due to physical clogging \([(K_\mathrm{i} - K_\mathrm{t})/K_\mathrm{i}]\) increased with decreasing \({D}_{15}/{d}_{85}\) ratios until a critical value of \({D}_{15}/{d}_{85}\), after which a surface mat of suspension was formed on the porous media. It was also found that the value of reduced permeability at any time (at any number of pore volumes of injected suspension-laden water), \(K_\mathrm{t}\), is directly proportional to square of \({D}_{15}\) and inversely proportional to \({C}_{\mathrm{u}}\) of the porous media and \({d}_{85}\) of suspensions. The effects of suspension type and flow rates on physical clogging seemed to depend on the size of the pores in the porous media.     

Characterization of similarities between two n-frames of projectors

An n-frame on a Banach space $\text{X}$ is E=(E₁,?, E_n) where the E_j's are bounded linear operators on $\text{X}$ such that E_j≠0,

$\text{∑}\text{j=1}\text{n}\text{E}{}_{\mathrm{j}}$

, and E_jE_k=δ_jkE_k (j, k=1,?, n). It is known that if two n-frames E and F are sufficiently close to each other, then they are similar, that is, F_j=TE_jT^-1 with T a bounded linear operator. Among the operators which realize the similarity of the two frames, there is the balanced transformation U(F, E)=(Σⁿ_j=1F_jE_j)(Σⁿ_j=1E_jF_jE_j)^{$\text{-1}\text{2}$}. One of our main results is a local characterization of the balanced transformation. Another operator which implements the similarity between E and F is the direct rotation R(F, E). It comes up in connection with the study of the set of all n-frames as a Banach manifold with an affine connection. Finally, it is shown that for quite a large set of pairs of 2-frames, the direct rotation has a global characterization.