Earticle

In organic chemistry amide synthesis is performed through condensation of a carboxylic acid and an amine with releasing one equivalent of water via the corresponding ammonium carboxylate salt. This method is suffering from tedious processes and poor atom-economy due to the adverse thermodynamics of the equilibrium and the high activation barrier for direct coupling of a carboxylic acid and an amine. Most of the chemical approaches to amides formations have been therefore being developed, they are mainly focused on secondary amides. Direct carbonylations of tertiary amines to amides have been an exotic field unresolved, in particular direct carbonylation of trimethylamine in lack of commercial need has been attracted much interests due to the versatile product of N,N-dimethylacetamide in chemical industries and the activation of robust N-C(sp3) bond in tertiary amine academically. This review is focused mainly on carbonylation of trimethylamine as one of the typical tertiary amines by transition metals of cobalt, rhodium, platinum, and palladium including the role of methyl iodide as a promoter, the intermediate formation of acyl iodide, the coordination ability of trimethylamine to transition metal catalysts, and any possibility of CO insertion into the bond of Me-N in trimethylamine. In addition reactions of acyl halides as an activated form of acetic acid with amines are reviewed in brief since acyl iodide is suggested as a critical intermediate in those carbonylations of trimethylamine.

Xanthine Oxidase is an enzyme, which oxidizes hypoxanthine to xanthine, and xanthine to uric acid. It is widely distributed throughout various organs including the liver, gut, lungs, kidney, heart, brain and plasma. It is involved in gout pathogenesis. Hence, in the present study, topomer based Comparative Molecular Field Analysis (topomer CoMFA) was performed on a series of Xanthine oxidase antagonist named 2-(indol-5-yl) thiazole derivatives. The best topomer CoMFA model was obtained with significant cross-validated correlation coefficient (q2 = 0.572) and non cross-validated correlation coefficients (r2 = 0.937). The model was evaluated with six external test compounds and its r2 pred was found to be 0.553. The steric and electrostatic contribution map show that presence of bulky and electropositive group in indole thiazole ring is necessary for improving the biological activities of the compounds. The generated topomer CoMFA model could be helpful for future design of novel and structurally related xanthine oxidase antagonists.

Organosilicon compound containing silphenylene unit as an eletrolyte for the application of lithium-ion batteries was synthesized by hydrosilylation method between 1,4-bis(dimethylsilylhydro)benzene and 3-[2-(2-methoxyethoxy)ethoxy]-1- propene. As-prepared new organosilicon compounds containing spacer such as propyl group with ethylene glycol are synthesized to improve thermal stability and to promote conductivity. The products are characterized by spectroscopic analysis.

Xanthine Oxidase is an enzyme, which oxidizes hypoxanthine to xanthine, and xanthine to uric acid. It is widely distributed throughout various organs including the liver, gut, lungs, kidney, heart, brain and plasma. It is involved in gout pathogenesis. Hence, in the present study, Hologram based Quantitative Structure Activity Relationship Study was performed on a series of Xanthine Oxidase antagonist named 2-(indol-5-yl) thiazole derivatives. The best HQSAR model was obtained using Atoms, Bonds, Connection, Hydrogen, Chirality and Donor Acceptor as fragment distinction parameter using hologram length 71 and 4 components with fragment size of minimum 2 and maximum 5. Significant cross-validated correlation coefficient (q2= 0.563) and non cross-validated correlation coefficients (r2= 0.967) were obtained. The model was then used to evaluate the six external test compounds and its r2 pred was found to be 0.798. Contribution map show that presence of propyl ring in indole thiazole makes big contributions for improving the biological activities of the compounds. We hope that our HQSAR model and analysis will be helpful for future design of xanthine oxidase antagonists.

CXC chemokine receptor 2 (CXCR2) is a prominent chemokine receptor on neutrophils. CXCR2 antagonist may reduce the neutrophil chemotaxis and alter the inflammatory response because the neutrophilic inflammation in the lung diseases is found to be largely regulated through CXCR2 receptor. Hence, in the present study, Topomer based Comparative Molecular Field Analysis (Topomer CoMFA) was performed on a series of CXCR2 antagonist named pyrimidine-5- carbonitrile-6-alkyl derivatives. The best Topomer COMFA model was obtained with significant cross-validated correlation coefficient (q2 = 0.487) and non cross-validated correlation coefficients (r2 = 0.980). The model was evaluated with six external test compounds and its r2 pred was found to be 0.616. The steric and electrostatic contribution map show that presence of bulkier and electropositive group around cyclopropyl ring may contribute more for improving the biological activities of these compounds. The generated Topomer CoMFA model could be helpful for future design of novel and structurally related CXCR2 antagonists.

In the terrain of the Korean peninsula, mountainous and flat lands are complexly distributed in small areas. Therefore, local severe weather develops and disappears in a short time due to the influence of the terrain. Particularly in the case of local severe weather with heavy wind that has the greatest influence on aviation meteorology, the scale is very small, and it occurs and disappears in a short time, so it is impossible to predict with fragmentary data alone. So, we use weather radar to detect and predict local severe weather. However, due to the development of wireless communication services and the rapid increase of wireless devices, radio wave jamming and interference problems occur. In this research, we confirmed through the cases that when the radio interference echo which is one of the non-precipitation echoes that occur during the operation of the weather radar is displayed in the image, its form and shape are shown in a long bar shape, and have a strong dBZ. We also found the cause of the interference through the radio tracking process, and solved through the frequency channel negotiation and AP output minimizing. The more wireless devices increase as information communication technology develops in the future, the more emphasized the problem of radio wave interference will be, and we must make the radio interference eliminated through the development of the radio interference cancellation algorithm.

Cryptand resins were synthesized by mixing 1-aza-18-crown-6 macrocyclic ligand with styrene divinylbenzene copolymer having 1%, 2%, 5%, and 10% crosslink by a substitution reaction. These synthetic resins were confirmed by chlorine content, elementary analysis, SEM, surface area, and IR-spectrum. As the results of the effects of pH, crosslink of synthetic resin, and dielectric constant of a solvent on uranium ion adsorption for resin adsorbent, the uranium ion showed high adsorption at pH 3 or over. Adsorption selectivity for the resin in methanol solvent was the order of uranium (UO2 2+) ＞calcium (Ca2+) ＞neodymium (Nd3+) ion, adsorbability of the uranium ion was the crosslink in order of 1%, 2%, 5%, and 10% and it was increased with the lower dielectric constant.

The researcher set up multiple sensor units on the road slope such as national highway and highway where there is a possibility of loss, and using the acceleration sensor built into the sensor unit the researcher will sense whether the inclination of the road slope occur in real time, and Based on the sensed data, the researcher tries to implement a system that detects collapse of road slope and dangerous situation. In the experiment of measuring the error between the actual measurement time and the judgment time of the monitoring system when judging the warning of the sensor and falling rock detection by using the acceleration sensor, the error between measurement time and the judgment time at the sensor warning was 0.34 seconds on average, and an error between measurement time and judgment time at falling rock detection was 0.21 seconds on average. The error is relatively small, the accuracy is high, and thus the change of the slope can be clearly judged.

We study the behavior of some invariants under completion. We also give a counterexample, which is the same as a counterexample to Ding's Conjecture, to Koh-Lee's Conjecture.

The Cu and CuSn/PVP nanofibers were fabricated by electrospinning method by controlling various parameters. The precursor solution was prepared with copper(II) acetate monohydrate (Cu(CH3COO)2) and tin chloride dihydrate (SnCl2·2H2O), and polyvinylpyrrolidone (PVP) for adjusting viscosity. The fabricated nanofibers were calcined at 873 K in Ar atmospheric environment for 5 hours to remove the solvent and polymer. The morphology and diameter of nanofibers were measured by optical microscopy (OM) with Motic image plus 2.0 program. The components and chemical environment were investigated with X-ray photoelectron spectroscopy (XPS). From the XPS survey spectra, we confirmed that CuSn/PVP nanofibers were successfully fabricated. The XPS peaks of C 1s and N 1s were remarkably decreased after calcination of the nanofibers at 873 K. It implies that the PVP was completely decomposed after calcination at 873 K.

The main focus when developing software is to improve the reliability and stability of a software system. We are enjoying a very comfortable life thanks to modern civilization, however, comfort is not guaranteed to us. Once software systems are introduced, the software systems used in the field environments are the same as or close to those used in the development-testing environment; however, the systems may be used in many different locations. Development of software system is a difficult and complex process. Generally, existing software reliability models are applied to software testing data and then used to make predictions on the software failures and reliability in the field. In this paper, we present an improved exponential NHPP software reliability model in different development environments, and examine the goodness-of-fit of improved exponential model and other model based on two datasets. The results show that the proposed model fits significantly better than other NHPP software reliability model.