Inhibition of Nicotine-Induced Toxicity by Curcumin and Curcumin Analog: A Comparative Study

M. Amarnath Satheesh,Venugopal P. Menon 한국식품영양과학회 2004 Journal of medicinal food Vol.7 No.4

The present study was undertaken to evaluate the effects of curcumin and curcumin analog on blood oxi-dantantioxidant status during nicotine-induced toxicity in male Wistar rats. Lung toxicity was induced by subcutaneous in-jection of nicotine at a dose of 2.5 mg/kg of body weight (5 days a week, for 22 weeks). The enhanced circulatory lipid per-oxides in nicotine-treated rats was accompanied by a significant decrease in the levels of ascorbic acid, vitamin E, reducedglutathione, glutathione peroxidase, superoxide dismutase, and catalase. There was a reduction in the levels of zinc with anelevation of copper and ferritin in nicotine-treated rats. Administration of curcumin and curcumin analog significantly low-ered the lipid peroxidation and enhanced the antioxidant status with modulation in the levels of zinc, copper, and ferritin.However, the effect was more significant in curcumin analog-treated rats than in curcumin-treated rats. The results of the pres-ent study suggest that curcumin and curcumin analog exert their protective effects by modulating the extent of lipid peroxi-dation and enhancing the antioxidant status.

Performance assessment of microwave treated WC insert while turning AISI 1040 steel

Durwesh Jhodkar,M. Amarnath,H. Chelladurai,J. Ramkumar 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.6

This study attributed to post treatment of tungsten carbide (WC) inserts using microwave irradiation. Tungsten carbide inserts were subjected to microwave radiation (2.45 GHz) to enhance its performance in terms of reduction in tool wear rate, cutting force surface roughness and improvement in tool life. Performance of tungsten carbide insert is very much affected by machine operating parameters i.e. speed, feed and depth of cut. An attempt has been made to investigate the effects of machining parameters on microwave treated tool inserts. This paper describes the comparative study of machining performance of untreated and microwave treated WC tool inserts used for turning of AISI 1040 steel. Machining performance has been evaluated in terms of flank wear, cutting force, surface roughness, tool wear mechanisms. Critical examinations of tool wear mechanisms and improvements in metallurgical properties such as microstructural change, phase activation of WC grains were identified using scanning electron microscope (SEM). Results obtained from the turning using the microwave treated tool inserts showed a significant reduction tool wear thereby enhancing the surface quality of workpiece.

스퍼 기어의 진동 신호와 비 유막 두께(Specific Film Thickness)의 상관관계에 관한 실험적 연구

김종식(Jong Sik Kim),M. Amarnath,이상권(Sang Kwon Lee) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.9

기어의 구동은 여러 기계요소에서 동력전달을 가능하게 해주는 가장 중요한 요소이다. 이러한 기어 접촉면에서의 상태는 마모, 재료의 변형 그리고 윤활 상태에 따라 크게 좌우되며, 이러한 상태 변화는 기어의 수명에 큰 영향을 준다. 따라서, 이러한 상태 진단에 대한 해법은 원활한 구동을 위한 필수요소이다. 기어의 상태 변화는 연마 마모(Abrasive wear), 점식 (Pitting), 스커핑(Scuffing), 스폴링(Spalling) 등을 유발하며, 이러한 마모들은 기어로부터 발생하는 진동 레벨을 상승시킨다. 본 연구에서는 스퍼 기어를 장착한 기어 박스를 이용한 실험적 연구를 통해 기어의 표면 피로 마모를 평가하기 위해 진동 신호로부터 구해진 통계적 변수들과 Stribeck Curve 와의 상관관계를 검증하였다. Gears are critical elements in automobiles, and their use as power transmitting machine elements in engineering applications is quite extensive. In the areas of contact between gear teeth, the condition of a gear is likely to deteriorate due to contact fatigue, wear, material defects, lubrication failure, etc. Thus, it is necessary to monitor its condition to ensure smooth power transmission. Gear teeth deterioration causes failures such as abrasive wear, scuffing, pitting, and spalling. These failures lead to a higher level of vibration signals in the gear system. This paper presents the results of an experiment on the surface fatigue wear of a spur gear system. The correlation between the estimated specific film thickness, statistical parameter of the vibration signals, and Stribeck curve was considered in this study.

Experimental investigations to establish correlation between Stribeck curve, specific film thickness and statistical parameters of vibration and sound signals in a spur gear system

Lee, Sang-Kwon,Amarnath, M SAGE Publications 2016 Journal of vibration and control Vol.22 No.6

<P>The use of a gear as a power transmitting machine element in engineering applications is quite extensive. Under service conditions gear teeth contacts have a tendency for deterioration due to contact fatigue, wear, material defects, lubrication failure etc. Gear teeth surface deterioration triggers several types of failures such as abrasive wear, scuffing, micro pitting and spalling. The abovementioned faults influence the changes in the vibration and sound signals in the gear system. This paper presents the novel results of experimental investigations carried out to assess the surface fatigue wear in a spur gear system. Estimation of specific film thickness, measurement of reduction in tooth thickness, visual examination of wear mechanisms on the gear teeth and their effects on the statistical parameters of vibration and sound signals are considered in this study. In order to confirm the hypothesis of dependency of surface fatigue wear, specific film thickness and sound and vibration signals the results of statistical parameters obtained from sound and vibration signals have been correlated with the Stribeck curve.</P>

스퍼 기어 시스템의 음향 신호와 비 유막 두께(Specific Film Thickness)의 상관관계에 관한 실험적 연구

김종식(Jongsik Kim),M. Amarnath,이상권(Sangkwon Lee) 한국소음진동공학회 2014 한국소음진동공학회 논문집 Vol.24 No.8

Gear transmission system is widely applied in engineering. As the problem of contact fatigue, wear, lubrication failure etc, the condition of gear teeth contacts will be worse. The vibration and sound signals in the gear system will be affected by the some failures like scuffing, abrasive wear and spalling due to the deterioration of gear teeth surface. By studying the estimation of specific film thickness, measurement of reduction in tooth thickness, visual examination of wear mechanisms on the gear teeth and their effects on the statistical parameters of vibration and sound signals, the research obtained the satisfactory results on accessing the surface fatigue wear in a spur gear system. The paper utilizes the relationship between statistical parameters obtained from sound signals and Stribeck curve to confirm the hypothesis of dependency of surface fatigue wear, specific film thickness.

Impact of Antioxidant Therapy on Natural Pregnancy Outcomes and Semen Parameters in Infertile Men: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Agarwal Ashok,Cannarella Rossella,Saleh Ramadan,Harraz Ahmed M.,Kandil Hussein,Salvio Gianmaria,Boitrelle Florence,Kuroda Shinnosuke,Farkouh Ala’a,Rambhatla Amarnath,Zini Armand,Colpi Giovanni,Gül Mur 대한남성과학회 2023 The World Journal of Men's Health Vol.41 No.1

Purpose: Seminal oxidative stress (OS) is a recognized factor potentially associated with male infertility, but the efficacy of antioxidant (AOX) therapy is controversial and there is no consensus on its utility. Primary outcomes of this study were to in-vestigate the effect of AOX on spontaneous clinical pregnancy, live birth and miscarriage rates in male infertile patients. Sec-ondary outcomes were conventional semen parameters, sperm DNA fragmentation (SDF) and seminal OS. Materials and Methods: Literature search was performed using Scopus, PubMed, Ovid, Embase, and Cochrane databases. Only randomized controlled trials (RCTs) were included and the meta-analysis was conducted according to PRISMA guide-lines. Results: We assessed for eligibility 1,307 abstracts, and 45 RCTs were finally included, for a total of 4,332 infertile patients. We found a significantly higher pregnancy rate in patients treated with AOX compared to placebo-treated or untreated con-trols, without significant inter-study heterogeneity. No effects on live-birth or miscarriage rates were observed in four studies. A significantly higher sperm concentration, sperm progressive motility, sperm total motility, and normal sperm morphology was found in patients compared to controls. We found no effect on SDF in analysis of three eligible studies. Seminal levels of total antioxidant capacity were significantly higher, while seminal malondialdehyde acid was significantly lower in patients than controls. These results did not change after exclusion of studies performed following varicocele repair. Conclusions: The present analysis upgrades the level of evidence favoring a recommendation for using AOX in male infertility to improve the spontaneous pregnancy rate and the conventional sperm parameters. The failure to demonstrate an increase in live-birth rate, despite an increase in pregnancy rates, is due to the very few RCTs specifically assessing the impact of AOX on live-birth rate. Therefore, further RCTs assessing the impact of AOX on live-birth rate and miscarriage rate, and SDF will be helpful.