Molecular assessment of clarithromycin resistant Helicobacter pylori strains using rapid and accurate PCR-RFLP method in gastric specimens in Iran

Currently, a seven-day, triple-drug regimen has been recommended as one of the first-line therapies for Helicobacter pylori management in which clarithromycin is a key component. Development of clarithromycin resistance leads to the long term assessment of the efficacy of clarithromycin in the triple-drug regimen. The aim of this study was to rapidly and directly assess clarithromycin resistance point mutations on gastric biopsy specimens by using PCR-RFLP method. Biopsy samples were obtained over a 6-months period of 2009, from 200 dyspeptic patients referred to Shahrekord University of Medical Sciences, Iran. Initially, rapid urease test was performed and then DNA was isolated from each tissue and used for molecular analysis such as PCR (for H. pylori diagnostic) and PCR-RFLP (for Cla resistance determination). RUT and PCR results showed that 164 (82%) of the patients were H. pylori-positive. Resistance was evaluated in 164 samples by using enzymes BsaI and MboII. Thirty nine (39) (23/78%) clarithromycin-resistant strains were detected which were identified as 15 (9.15%) A2143G, 15 (9.15%) A2142G and 9 (5.49%) mix strains. The results showed that PCR-RFLP method had a high accuracy to detect A2142G and A2143G mutations associated with resistance to clarithromycin in the minimum possible time.Key words: Helicobacter pylori, clarithromycin resistance, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)

DABCO as a novel and efficient catalyst for the synthesis of 4(3H)-quinazolinone derivatives

4(3H)-Quinazolinones were synthesized in high to excellent yields through the one-pot condensation of anthranilic acid, trimethyl orthoformate and primary amines in the presence of DABCO under solvent free conditions.KEY WORDS: 4(3H)-Quinazolinone, DABCO (1,4-diazabicyclo[2,2,2]octane), Trimethyl orthoformate, Anthranilic acid Bull. Chem. Soc. Ethiop. 2011, 25(2), 305-308

Mesoporous molecular sieve MCM-41 catalyzed one-pot synthesis of 3,4-dihydro-2(1H)-pyrimidinones and –thiones under solvent-free conditions

An efficient synthesis of 3,4-dihydro-2(1H)-pyrimidinones and -thiones using MCM-41 as the catalyst from an aldehyde, β-keto ester, and urea or thiourea under solvent-free conditions is described.KEY WORDS: Biginelli reaction, Dihydropyrimidinones, MCM-41, One-pot, Reusable Bull. Chem. Soc. Ethiop. 2011, 25(2), 309-313

EFFICIENT SODIUM SELENATE-CATALYZED SYNTHESIS OF 3,4-DIHYDRO-2(1H)-PYRIMIDINONES AND –THIONES UNDER SOLVENT-FREE CONDITIONS

Sodium selenate efficiently catalyzes the three-component Biginelli reaction of an aldehyde, a,β-keto ester and urea or thiourea under solvent-free conditions to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones or –thiones in excellent yields. KEY WORDS: Dihydropyrimidinones, Sodium selenate, Biginelli reaction, Three component reaction Bull. Chem. Soc. Ethiop. 2009, 23(1), 141-144

A catalytic method for the synthesis of 4-alkyl(aryl)-6-aryl-3-cyano-2(1H)-pyridinones and their 2-imino isosteres as nonsteroidal cardiotonic agents

A highly efficient procedure for the synthesis of 4-alkyl(aryl)-6-aryl-3-cyano-2(1H)-pyridinones and their 2-imino isosteres via a one-pot multicomponent reaction of 3,4-dimethoxyacetophenone, malonitrile or ethyl cyanoacetate, an aldehyde and ammonium acetate in the presence of K2CO3 is achieved in good yields. KEY WORDS: 3-Cyano-2(1H)-pyridinones, 2-Imino, Cardiotonic, Dimethoxyacetophenone  Bull. Chem. Soc. Ethiop. 2010, 24(3), 433-438

The synthesis of 2-iminochromenes using mesoporous molecular sieve MCM-41 as a heterogeneous and recyclable catalyst

A highly efficient procedure for the synthesis of 2-iminochromenes via condensation of o-hydroxybenzaldehydes and malononitrile using a catalytic amount of mesoporous molecular sieve MCM-41 in good yields is achieved. KEY WORDS: 2-Iminochromenes, Recyclable catalyst, MCM-41, o-Hydroxybenzaldehydes  Bull. Chem. Soc. Ethiop. 2010, 24(2), 273-276

Europium oxide nanorod-reduced graphene oxide nanocomposites towards supercapacitors

Fast charge/discharge cycles are necessary for supercapacitors applied in vehicles including, buses, cars and elevators. Nanocomposites of graphene oxide with lanthanide oxides show better supercapacitive performance in comparison to any of them alone. Herein, Eu2O3nanorods (EuNRs) were prepared through the hydrothermal method and anchored onto the surface of reduced graphene oxide (RGO) by utilizing a sonochemical procedure (in an ultrasonic bath) through a self-assembly methodology. The morphologies of EuNRs and EuNR-RGO were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and IR spectroscopy. Then, we used EuNRs and EuNR-RGO as electrode materials to investigate their supercapacitive behavior using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. In a 3.0 M KCl electrolyte and with a scan rate of 2 mV s-1, EuNR-RGO exhibited a specific capacity of 403 F g-1. Galvanostatic charge-discharge experiments demonstrated a specific capacity of 345.9 F g-1at a current density of 2 A g-1. The synergy between RGO's flexibility and EuNR's high charge mobility caused these noticeable properties. © The Royal Society of Chemistry 2020

Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

基于隧穿机制的电输运是物质世界的基本过程之一。在单分子尺度，分子结构的细微变化足以导致电学性质的显著区别，这也使通过单分子电学检测方法研究化学反应过程成为可能。在这一研究工作中，课题组将通常用于单分子电学测量的裂结技术用于单分子尺度反应动力学的表征。这一工作也为未来的合成化学和化学工程研究提供了一种新思路，即通过纳米技术构造反应微环境，可以实现化学反应速率、产物和产率的优化。 该研究工作是在洪文晶教授和丹麦哥本哈根大学Mogens B. Nielsen教授的共同指导下，通过跨学科的国际合作所完成的。其中洪文晶教授课题组负责该研究工作的实验表征和统计分析，丹麦哥本哈根大学Mogens B. Nielsen教授课题组负责分子体系的合成，Kurt V. Mikkelsen教授和Gemma C. Solomon教授课题组分别负责了该研究工作的反应动力学和电输运理论计算，这也是洪文晶教授课题组与上述研究团队的首次科研合作。我校萨本栋微纳研究院的杨扬助理教授也参与了数据分析和机理讨论的部分工作。 洪文晶教授课题组长期致力于单分子尺度下的化学反应、分子组装、分子器件电输运等方面的相关研究，开发了一系列能够在单分子尺度实现精密控制和精确测量的科学仪器。以此为基础，课题组与国内外材料化学和理论研究团队密切合作，在单分子尺度电输运的量子干涉效应、电化学调控和化学反应表征等领域进行了一系列探索。【Abstract】Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.This work was generously supported by the University of Copenhagen, the Danish e-Infrastructure Cooperation, the European Union Seventh Framework Programme (FP7/2007-2013) under the ERC grant agreement no.258806, the Danish Council for Independent Research—Natural Sciences, the Carlsberg foundation, NSFC (21673195,21503179), EC FP7 ITNs ‘MOLESCO’ project numbers 606728, and the Young Thousand Talent Project of China. 研究工作得到了国家自然科学基金（21673195，21503179）、固体表面物理化学国家重点实验室、能源材料化学协同创新中心（2011-iChEM）的大力资助与支持