An investigation into the biocidal effect of high voltage AC/DC atmospheric corona discharges on bacteria,yeasts, fungi and algae

A newly developed, low cost plasma system that works at atmospheric pressure and operates with both DC or AC high voltage power supplies was presented. This system was tested for its biocidal effect on a wide range of micro-organisms in water. Optimal killing parameters such as time, temperature and AC and DC high voltage power levels were tested for bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans, Bacillus subtilis), yeast (Candida albicans), fungi (Aspergillus niger) and green algae. Results show this system to have a very efficient biocidal effect on most bacteria, algae and fungi in water.     

Theoretical and antimicrobial activity study for ethyl{4-[3-(1H-imidazole-1-yl)propyl]-3-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}acetate

Ethyl{4-[3-(1H-imidazole-1-yl)propyl]-3-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}-acetate (I) was synthesized as described in the literature and studied by proton and carbon-13 nuclear magnetic resonance, Fourier transform infrared spectroscopic techniques. Theoretical calculations were performed by the density functional method with 6-311G(d,p) and 6-311++G(d,p) basis sets. Structural parameters of compound I, vibrational frequencies, and chemical shift values were determined. The antimicrobial activity of compound I was tested for seven standard bacteria; Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Yersinia enterocolitica, Listeria monocytogenes, Shigella flexneri, Pseudomonas aeruginosa, and one standard fungi isolate by microdilution broth assay with Alamar Blue Dye. The in vitro results show that compound I has antimicrobial activity against to two standard bacteria, Shigella flexneri and Listeria monocytogenes. And also, the antifungal activity was not detected against selected fungi isolate, Candida tropicalis.     

Three-dimensional numerical investigation of heat transfer for plate fin heat exchangers

In the present study, the potential of rectangular fins with 30° and 90° angle and 10 mm offset from the horizontal direction for heat transfer enhancement in a plate fin heat exchanger is numerically evaluated with conjugated heat transfer approach. The rectangular fins are mounted on the flat plate channel. The numerical computations are performed by solving a steady, three-dimensional Navier–Stokes equation and an energy equation by using Fluent software program. Air is taken as working fluid. The study is carried out at Re = 400 and inlet temperatures, velocities of cold and hot air are fixed as 300, 600 K and 1.338, 0.69 m/s, respectively. Colburn factor j versus Re design data is presented by using Fluent. The results show that the heat transfer is increased by 10 % at the exit of channel with fin angle of 30° when compared to channel without fin for counter flow. The heat transfer enhancement with fins of 30° and 90° for different values of Reynolds number with 300, 500 and 800 and for varying fin heights, fin intervals and also temperature distributions of fluids on the top and bottom surface of the channel are investigated for parallel and counter flow.     

Novel thiazole‐piperazine derivatives as potential cholinesterase inhibitors

Dementia is a cognitive disorder mostly associated with Alzheimer's disease (AD) in addition to being seen in many other diseases of the central nervous system (CNS). The limited number of drugs is not sufficient to provide adequate improvement to increase the quality of life of patients suffering from this symptom; therefore, all treatment options should be evaluated in detail. In this study, new molecules, [2‐(4‐(2/3/4‐substituted phenyl)piperazin‐1‐yl)‐4‐phenylthiazol‐5‐yl][3/4‐substituted phenyl]methanone derivatives ( 1‐44 ), were obtained and analyzed in terms of their anticholinesterase activities. Kinetic mode and molecular interactions were also evaluated. An enzyme inhibition study was undertaken on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using the Ellman method. Maestro program was used in molecular modeling studies. Forty‐four compounds were evaluated on AChE and BChE enzymes at 10^?3 and 10^?4 concentrations. The inhibition concentrations were calculated as 0.268μM to 2.104μM for six compounds ( 4 , 5 , 16 , 27 , 37 , and 38 ) on AChE. Compound 5 including the 4‐methoxy substituent (IC₅₀: 0.268μM) and compound 38 containing the 4‐methoxy and 3‐methyl substituents (IC₅₀: 0.286μM) showed the highest AChE inhibitory activity. They were further examined in terms of hydrogen bonding with Arg296 and Ar‐Ar interaction with Trp286. The activity of compound 5 was also assessed in mixed‐type kinetic mode.     

A Green Protocol for Simple One‐pot Synthesis of New Pyrimidine Derivatives Both Microwave Irradiation and Conventional Heating: Reactions,Characterization, and Theoretical Calculations

In this research, 5‐benzoyl‐6‐phenyl‐4‐(4‐trifluoromethylphenyl)‐2‐{oxo and thioxo}‐3,4‐dihydro‐1H‐pyrimidines ( 1 , 2 ) were synthesized by using multicomponent cyclocondensation reaction under microwave irradiation and classical heating. Compounds 3 , 4 , 6 , 7 , and 8 obtained reactions of 5‐benzoyl‐6‐phenyl‐4‐(4‐trifluoromethylphenyl)‐2‐thioxo‐3,4‐dihydro‐1H‐pyrimidine ( 1 ) and acetic anhydride, diethyl 2‐bromomalonate, bromoacetic acid, 3‐bromopropionic acid, methyl iodide, respectively. Compound 4 was both acetylated and hydrolyzed in acetic acid to give compound 5 . The structures of all compounds were determined by using spectroscopic techniques like FT‐IR, ¹H/¹³C NMR, and elemental analyses, and the structures of compounds 1 and 3 were analyzed by X‐ray crystal analysis. In addition, the quantum chemical parameters and full geometry optimizations for all compounds were computed using density functional theory based on B3LYP and the 6‐31G (d, p) basis set.     

Concise design and synthesis of pyridine-fused heterocycles via 6π-Azaelectrocyclization process of iminoalkyne derivatives

A concise and regioselective approach to the synthesis of pyridine-fused heterocycles and benzoxazepine derivatives was developed. Propargyl imines derived from aromatic aldehydes and propargyl amine underwent 6π-electrocyclization reactions at high temperatures in high yields to form pyridine-fused heterocycles. Application of the same methodology to aromatic imines having a hydroxyl group in the ortho position resulted in the formation of (benz)oxazepine derivatives. The formation mechanism of the products was discussed.     

A steady state quantum classifier

We report that under some specific conditions a single qubit model weakly interacting with information environments can be referred to as a quantum classifier. We exploit the additivity and the divisibility properties of the completely positive (CP) quantum dynamical maps in order to obtain an open quantum classifier. The steady state response of the system with respect to the input parameters was numerically investigated and it's found that the response of the open quantum dynamics at steady state acts non-linearly with respect to the input data parameters. We also demonstrate the linear separation of the quantum data instances that reflects the success of the functionality of the proposed model both for ideal and experimental conditions. Superconducting circuits were pointed out as the physical model to implement the theoretical model with possible imperfections.     

Preparation,characterization, and antibacterial activity of organo-sepiolite/chitosan/silver bionanocomposites

Bionanocomposites with different loadings of silver (Ag) were prepared via synthesis of Ag nanoparticles (AgNPs) using the wet chemical reduction method in the lamellar space layer of the organo-sepiolite/chitosan (O-SEP/CS). The prepared O-SEP/CS/Ag bionanocomposites were characterized using various analysis methods for their structure, morphology, and optical properties. The characteristic absorption bands from the UV–visible absorption spectrum confirmed the formation of AgNPs. The antibacterial activities of O-SEP/CS/Ag bionanocomposites were investigated against gram-positive and gram-negative bacteria using the disc diffusion method. The results suggest that O-SEP/CS/Ag bionanocomposites can be useful in wide range of bio-medical applications because of high antibacterial activity.     

Cu(I)-catalyzed alkyne–azide ‘click’ cycloaddition (CuAAC): a clean,efficient, and mild synthesis of new 1,4-disubstituted 1H-1,2,3-triazole-linked 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile–crystal structure

Research on Chemical Intermediates - Cu(I)-catalyzed alkyne–azide ‘click’ cycloaddition (CuAAC) is an important ‘‘click chemistry’’ reaction that is widely...     

Laser pulse optimization for practical laser drilling

Laser drilling is a common commercially developed technique for material processing. From the application viewpoint, it is the end product for a laser system, for instance a drilled hole, that matters. Laser pulse profile is the most important parameter controlling the laser hole drilling process. An efficient and practical method is therefore needed to develop a relationship between the pulse parameters and the depth of hole produced in a known material. In the present study, dimensionless groups are developed to optimize laser pulse parameters to give information on workpiece materials. Consequently, an optimal laser pulse for drilling an aluminum workpiece is predicted.