Induction of Apoptosis by Eugenol and Capsaicin in Human Gastric Cancer AGS Cells - Elucidating the Role of p53

Sarkar, Arnab,Bhattacharjee, Shamee,Mandal, Deba Prasad Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: Loss of function of the p53 gene is implicated in defective apoptotic responses of tumors to chemotherapy. Although the pro-apoptotic roles of eugenol and capsaicin have been amply reported, their dependence on p53 for apoptosis induction in gastric cancer cells is not well elucidated. The aim of the study was to elucidate the role of p53 in the induction of apoptosis by eugenol and capsaicin in a human gastric cancer cell line, AGS. Materials and Methods: AGS cells were incubated with or without various concentrations of capsaicin and eugenol for 12 hrs, in the presence and absence of p53 siRNA. Cell cycling, annexin V and expression of apoptosis related proteins Bax, Bcl-2 ratio, p21, cyt c-caspase-9 association, caspase-3 and caspase-8 were studied. Results: In the presence of p53, capsaicin was a more potent pro-apoptotic agent than eugenol. However, silencing of p53 significantly abrogated apoptosis induced by capsaicin but not that by eugenol. Western blot analysis of pro-apoptotic markers revealed that as opposed to capsaicin, eugenol could induce caspase-8 and caspase-3 even in the absence of p53. Conclusions: Unlike capsaicin, eugenol could induce apoptosis both in presence and absence of functional p53. Agents which can induce apoptosis irrespective of the cellular p53 status have immense scope for development as potential anticancer agents.

Extreme Wind Climate Modeling of Some Locations in India for the Specification of the Design Wind Speed of Structures

Arnab Sarkar,Navneet Kumar,Debojyoti Mitra 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.5

The wind load on a structure is proportional to the square of the wind speed. Extreme wind climate modeling should be requiredfor specifying the design wind speed of structures. Extreme wind speeds for a storm type should be fitted in a suitable probabilitydistribution, from which the design wind speed can be specified for a particular service life of a structure. The methodology, used inIndia for the specification of the design wind speed of existing structures, is fairly old and should be updated. Extreme wind climatein India is mainly influenced by thunderstorms and cyclones. Because thunderstorms and cyclones occur due to different geophysicalreasons, it is necessary to fit extreme events of these two storm types in separate probability distributions, which can be subsequentlycombined to determine the overall non-exceedance probability. For a thunderstorm analysis, the wind speed data for three stationswere considered, namely Kolkata, Lucknow and New Delhi. However, the statistical analysis greatly suffered due to the lowensemble size in Lucknow. Moreover, cyclones very rarely occur; as a result, cyclone modeling for the Bay of Bengal (total eastcoast) was initially considered to obtain a sufficient ensemble size. This paper provides a strategy to determine the specification of thedesign wind speed of structures at a particular location, which is affected by both thunderstorms and cyclones. The motivation of thiswork is to improve the current design methodology as well as the national code of standards to make engineering structures in Indialess vulnerable to damage due to strong winds.

Weibull Model for Wind Speed Data Analysis of Different Locations in India

Arnab Sarkar,Gaurav Gugliani,Sneh Deep 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7

Wind speed data should be fitted by a suitable statistical model like Weibull to determine expected number of hours per year in the critical wind speed range for a slender structure, which is required to determine the expected number of stress cycles in the projected working life of the structure. Apart from this, for the assessment of wind energy potential wind speed data should be fitted by an appropriate probability distribution. In the present scope of study, wind data of various locations of India have been fitted by Weibull model. Wind speed data are initially sampled in knot by Indian Meteorological Department and later converted into integer km/h before supplying them to the end user. Due to this conversion, wind speed data cannot be properly fitted by Weibull distribution and in this regard, the choice of appropriate class width becomes very much important. Without the choice of appropriate class width, estimated Weibull parameters become biased which would yield incorrect estimation of expected number of hours in critical wind speed ranges as well as wind energy potential. After taking appropriate class width of 4 km/h, it has been found that Weibull model is an adequate model to describe wind speed distributions of India. Weibull model has also been compared with other models such as Gamma and inverse Weibull distributions to establish its suitability than the others. In this study, the values of Weibull shape parameters vary from 1.3 to 2.3, whereas the values of scale parameters vary from 1.4 m/s to 6.5 m/s. The validity of Weibull model is also verified with a target confidence interval of 90%. The uncertainties involved in the estimation of available wind energy potential as well as the expected number of hours per year in critical wind speed ranges have also been considered due to random variation of wind climate in each year.

Weibull and Generalized Extreme Value Distributions for Wind Speed Data Analysis of Some Locations in India

Arnab Sarkar,Sneh Deep,D. Datta,Amit Vijaywargiya,R. Roy,V. S. Phanikanth 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.8

Wind velocity data modeling plays a crucial role for the estimation of wind load and wind energy. Apart from these, the same modeling must also be used in the load cycle analysis of fatigue failure in slender structures to address periodic vortex shedding. Most authors fitted the entire available range of wind velocities of various locations using Weibull models. However, they did not check the validity of the model in describing the range of extreme wind velocity. In this work, the validity of Weibull models for describing parent as well as extreme hourly mean wind velocity data for four places on the east coast of India has been checked. While it predicts lower wind speeds accurately, the Weibull model has been found to become inappropriate for describing wind velocity in the range of extremes, i.e., above a certain threshold value. Therefore, this article focuses on the techniques of determininga limiting wind velocity beyond which the Weibull distribution is rendered unsuitable. In the range where the Weibull distributionfails, various extreme value distributions, such as Gumbel, Fréchet and reverse Weibull distributions have been compared, therebydetermining the best estimator for each location.

Interfacial Microstructural and Corrosion Characterizations of Friction Stir Welded AA6061‑T6 and AISI304 Materials

Raju Prasad Mahto,Sharath Anishetty,Arnab Sarkar,Omkar Mypati,Surjya Kanta Pal,Jyotsna Dutta Majumdar 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3

The use of aluminum in conjunction of steel can reduce the weight of structures but dissimilar materials welded structureresults in the formation of intermetallic compounds and inhomogeneous distribution of grains. Since aluminum is moreactive than the steel, the structures made from such dissimilar materials can be affected from corrosion medium which needsto be investigated. In the present work, friction stir welding has been used to join AA6061-T6 and AISI304 in lap configuration,each having a thickness of 1 mm under varied process parameters. The detailed investigations have been made whichincludes understanding the effect of process variables on microstructures, intermetallic compounds and their phases, andthereby on corrosion of the aluminum-steel welded joint. SEM with integrated EBSD detector and XRD analyses have beencarried out to characterize the weld interface that revealed the evolution of grain boundaries and existence of phases suchas Fe2Al5and AlCrFe2. The grain size of the weld zone has been found to be decreasing with increase in weld speed andplunge depth. The temperature profiles have shown a faster rate of heating and cooling with increase in welding speed andplunge depth which led to the refinement of microstructure. The evolution precipitates mainly comprised of Al, Mg and Sias the major elements. The corrosion rate was found to be increasing with decrease in grain size. Samples were corroded bypitting corrosion, inter-granular corrosion, and environmental corrosion. Severity of pits have been found to be non-uniformin the along weld cross-section.

Biochemical and microbial profiling establish “Eu” (a traditional fermented beverage of Toto people) as a probiotic health drink

Soumita Bhattacharjee,Pallab Kar,Indrani Sarkar,Arnab Sen,Chandra Ghosh 한국식품연구원 2021 Journal of Ethnic Foods Vol.8 No.-

“Eu,” is a traditional millet-based mild alcoholic beverage consumed by the Toto tribe of West Bengal. Eu is prepared through the fermentation of millet with locally groomed starter culture “Moaa.” The study highlighted the overview of the traditional process of Eu preparation along with its molecular and biochemical characterization. Semi-structured interviews were conducted for collecting the ethnobotanical data and the samples. We have also included qualitative assays like acute toxicity, antioxidant, gas chromatography-mass spectrometry (GC-MS), molecular docking, and physiochemical characteristics such as pH and alcohol content. Moreover, metagenomics of the starter culture has been reported. This type of study on Eu has not been done previously. Therefore, it seems to be a pioneer report especially on the metagenomic analysis of Eu. Results revealed that Eu has a very low alcohol content (approximately 1-3%) and a high antioxidant capacity. GC-MS analysis identified thirteen different bioactive compounds. Metagenomics analysis revealed that the Eu has a high source of various beneficial gut microflora. Overall Lactobacillus, Lactococcus, Enterococcus, Leuconostoc, and Pediococcus are dominant genera identified in the starter culture. The present study revealed that the consumption of Eu is safe and has the potential to scavenge reactive oxygen species (ROS). Hence, the commercialization of Eu can be an alternative source of income for the poor endangered Toto tribe.