Fabrication, Mechanical and Wear Properties of Aluminum (Al6061)-Silicon Carbide-Graphite Hybrid Metal Matrix Composites

In recent times, the use of aluminum alloy-based Hybrid Metal Matrix Composites (HMMCs) is being increased in aerospace and automotive applications. HMMCs compensate for the low desirable properties of each filler used. However, the mechanical properties of HMMCs are not well understood. In particular, microstructural investigations and wear optimization studies of HMMCs are not clear. Therefore, further studies are required. The present study is aimed at fabricating and mechanical and wear characterizing and microstructure investigating of Silicon Carbide (SiC) and Graphite (Gr) added in Aluminum (Al) alloy Al6061 HMMCs. The addition of SiC particles was in the range from 0 to 9 weight percentage (wt.%) in steps of 3, along with the addition of 1 wt.% Gr in powder form. The presence of alloying elements in the Al6061 alloy was identified using the Energy Dispersive X-Ray Analysis (EDX). The dispersion of SiC and Gr particles in the alloy was investigated using metallurgical microscope and Scanning Electron Microscopy (SEM). The gain in strength can be attributed to the growth in dislocation density. The nature of fracture was quasi-cleavage. The microstructure examination reveals the uniform dispersion of the reinforcement. Density, hardness, and Ultimate Tensile Strength values observed to be increased with increased contents of SiC reinforcement. Besides, wear studies were performed in dry sliding conditions. Optimization studies were performed to investigate the effect of parameters that affecting the wear. The sliding wear resistance was noticed to be improved concerning higher amounts of reinforcement leading to a decrease in delamination and adhesive wear. The predicted values for the wear rate have also been compared with the experimental results and good correlation is obtained

Synthesis and evaluation of 3-(2,4-{Dioxo}-1,3,8-triazaspiro4.6]undec-3-yl) methyl]benzonitrile derivatives as potential anticonvulsants

New 3-(2,4-dioxo-1,3,8-triazaspiro4.6]undec-3-yl)methyl]benzonitrile derivatives 8-37 were synthesized and their pharmacological activities were determined with the objective to better understand their structure-activity relationship (SAR) for anticonvulsant activity. All the compounds were evaluated for their possible anticonvulsant activity by maximal electroshock seizure (MES) and pentylenetetrazole (PTZ) test. Compounds 11, 18, 31, and 32 showed significant and protective effect on seizure, when compared with the standard drug valproate. The same compounds were found to exhibit advanced anticonvulsant activity as well as lower neurotoxicity than the reference drug. From this study, it is quite apparent that there are at least three parameters for the activity of anticonvulsant drugs, that is, a lipophilic domain, a hydrophobic center, and a two-electron donor. A series of 3-(2,4-Dioxo-1,3,8-triazaspiro4. 6]undec-3-yl)methyl]-benzonitrile derivatives 8-37 were synthesized and evaluated for their anticonvulsant activity. The most promising compounds 11, 18, 31, and 32 showed significant and protective effects on seizure. The novel anticonvulsant agents include essential pharmacophoric elements in their structure

Synthesis and evaluation of novel imidazo[4,5-c]pyridine derivatives as antimycobacterial agents against Mycobacterium tuberculosis

The current study involves the synthesis of novel imidazo4{,}5-cpyridine derivatives (IPD) containing amide/urea/sulfonamide. The synthesized compounds were evaluated for in vitro and in vivo antimycobacterial activities against Mycobacterium tuberculosis. The pharmacological activities were determined by the objective to better understand their structure–activity relationship (SAR) for their in vitro antimycobacterial activity against M. tuberculosis. Some synthesized compounds showed significant activity against M. tuberculosis based on the agar dilution method. Among the forty-one compounds screened{,} compounds 21{,} 22 and 23 were found to be the most active compounds against M. tuberculosis. In the in vivo animal model{,} 21{,} 22 and 23 decreased the bacterial load in lung and spleen tissues at the dose of 50 mg kg−1 body weight

Synthesis and structure-activity relationship studies on novel 8-amino-3-2-(4-fluorophenoxy)ethyl-1,3-diazaspiro4.5decane-2,4-dione derivatives as anticonvulsant agents

A series of novel 8-amino-3-2-(4-fluorophenoxy)ethyl-1,3-diazaspiro4.5 decane-2,4-dione derivatives 7-36 was synthesized and their pharmacological activity was determined with the objective to better understand their structure-activity relationship for anticonvulsant activity. All the compounds were evaluated for their possible anticonvulsant activity by maximal electroshock seizure (MES) test and their neurotoxic effects were determined by rotarod test. Majority of the compounds were active in MES tests. Compounds 24, 27, and 34 showed a significant and protective effect on seizure, when compared with standard drug phenytoin. The compounds having amide bond showed moderate protective effect on MES induced seizures compared to sulfonamide

Synthesis, anticonvulsant, antioxidant and binding interaction of novel N-substituted methylquinazoline-2,4(1H, 3H)-dione derivatives to bovine serum albumin: A structure-activity relationship study

A novel class of N-substituted glycosmicine derivatives was synthesized, and their anticonvulsant, antioxidant activity and interaction with bovine serum albumin (BSA) were evaluated. The synthesized compounds 4a-j were examined for anticonvulsant activity by maximal electroshock induced seizures (MESs) test and their neurotoxic effects were determined by rotorod test in mice. The structure-activity relationships (SARs) of these compounds were also investigated. Compounds 4d, 4g, 4i and 4j were found to have good protective effect from seizure. The in vitro antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging assay. The interaction between novel N-substituted methylquinazoline-2,4(1H, 3H)-dione (NMQ) and BSA was analyzed by fluorescence and ultraviolet spectroscopy at 304 K under simulative physiological conditions. BSA fluorescence quenched by NMQ is discussed according to the Stern-Volmer equation. The binding constant and binding sites of NMQ with BSA were calculated. According to Forster non-radiation energy transfer theory, the binding distance (r) between NMQ and BSA was calculated

Synthesis and structure-activity relationship studies on novel 8-amino-3-2-(4-fluorophenoxy)ethyl-1,3-diazaspiro4.5decane-2,4-dione derivatives as anticonvulsant agents

A series of novel 8-amino-3-2-(4-fluorophenoxy)ethyl-1,3-diazaspiro4.5 decane-2,4-dione derivatives 7-36 was synthesized and their pharmacological activity was determined with the objective to better understand their structure-activity relationship for anticonvulsant activity. All the compounds were evaluated for their possible anticonvulsant activity by maximal electroshock seizure (MES) test and their neurotoxic effects were determined by rotarod test. Majority of the compounds were active in MES tests. Compounds 24, 27, and 34 showed a significant and protective effect on seizure, when compared with standard drug phenytoin. The compounds having amide bond showed moderate protective effect on MES induced seizures compared to sulfonamide

Synthesis and anticonvulsant activity of N-(substituted)-1-methyl-2,4-dioxo-1,2-dihydroquinazoline-3(4H)-carboxamides

A series of new N‐(substituted)‐1‐methyl‐2,4‐dioxo‐1,2‐dihydroquinazoline‐3(4H)‐carboxamides were designed, synthesized, and evaluated for their anticonvulsant activity. Most of the synthesized compounds exhibited potent anticonvulsant activities in the maximal electroshock (MES) and pentylenetetrazol (PTZ) test. The most promising compound 4c showed significant anticonvulsant activity with a protective index value of 3.58. The compounds 4a–c were also found to have encouraging anticonvulsant activity in the MES and PTZ screen when compared with the standard drugs, valproate and methaqualone. The same compounds were found to exhibit advanced anticonvulsant activity as well as lower neurotoxicity than the reference dru

Synthesis, characterization, antidepressant and antioxidant activity of novel piperamides bearing piperidine and piperazine analogues

A series of piperamide derivatives (8a–j) was synthesized with various substituted piperidine and piperazine compounds. The prepared compounds were evaluated for antibacterial activity against gram-positive and gram-negative bacteria and antifungal activity by disc diffusion method. The antioxidant activity of the compounds was evaluated by DPPH and superoxide radical scavenging method and antidepressant activity using forced swim and tail suspension behavioral despair tests in mice. The compounds 8a, 8b and 8c were investigated for their monoamine oxidase A and B (MAO-A and MAO-B) inhibitory property. Some of the test compounds were active in forced swim test (FST) and tail suspension test (TST). Compounds 8a and 8b showed a significant effect, when compared to standard drug, clorgyline

Synthesis, characterization, and evaluation of difluoropyrido4,3-bindoles as potential agents for Acetylcholinesterase and Antiamnesic activity

Acetylcholinesterase (AChE) inhibitors are currently the most widely prescribed drugs for Alzheimer's disease. The high potential of indole compounds in medicinal chemistry led us to discover a novel series of fluoroindole compounds. The synthesis and pharmacological analysis of the difluoropyrido4,3-bindoles 11–34 are described. Compounds 11–34 were tested for AChE inhibition activity using a rat brain homogenate. Compounds 25–29 display a promising in vitro profile with an IC50 value range of 46–51.6 nM and show significant protective effect on scopolamine-induced amnesia. The present data indicate that compounds 25–29 may represent attractive potent molecules for the treatment of Alzheimer's disease