Computational Kinetic Studies of Pyruvate Metabolism in Carboxydothermus hydrogenoformans Z-2901 for Improved Hydrogen Production

Rajadurai Chinnasamy Perumal,Ashok Selvaraj,Saranya Ravichandran,Gopal Ramesh Kumar 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.3

Hydrogen is considered as a renewable energy source and it is also regarded as future fuel. Currently,hydrogen production through a biotechnological approach is a research priority. Hydrogenogens, a microbial species,are of significant interest to researchers because of their ability to produce biological hydrogen. Carboxydothermus hydrogenoformans Z-2901 is one among the hydrogenogens that can grow anaerobically by utilizing pyruvate as a carbon source, and can produce molecular hydrogen. In the present study, we performed an in silico kinetic simulation using the available Kyoto Encyclopedia of Genes and Genomes (KEGG) model and reconstructed pyruvate metabolism in C. hydrogenoformans Z-2901. During this metabolism, dissimilation of pyruvate leads to the formation of energy co-factors, such as ATP and NAD+/NADH, and the level of these co-factors influences the specific growth rate of organism and hydrogen production. Our strategy for improving hydrogen production involves maximizing the ATP and NAD+ yield by modification of kinetic properties and adding new reactions in pyruvate metabolism through metabolic pathway reconstruction. Moreover,the influence of phosphoenol pyruvate carboxylase and pyruvate dehydrogenase enzyme concentration on cofactor productions was also simulated. The theoretical molar yield of ATP and NAD+ were obtained as 2.32 and 1.83mM, respectively, from 1 mM/mg of phosphoenol pyruvate (PEP) utilization. A higher yield of ATP is achieved when the PEP level reaches 5 mM/mg. This work also suggests that PEP can be considered as an alternative substrate. In conclusion, the simulation results reported in this paper can be applied to design and evaluate strategies of strain construction for optimal hydrogen yield in C. hydrogenoformans. Hydrogen is considered as a renewable energy source and it is also regarded as future fuel. Currently,hydrogen production through a biotechnological approach is a research priority. Hydrogenogens, a microbial species,are of significant interest to researchers because of their ability to produce biological hydrogen. Carboxydothermus hydrogenoformans Z-2901 is one among the hydrogenogens that can grow anaerobically by utilizing pyruvate as a carbon source, and can produce molecular hydrogen. In the present study, we performed an in silico kinetic simulation using the available Kyoto Encyclopedia of Genes and Genomes (KEGG) model and reconstructed pyruvate metabolism in C. hydrogenoformans Z-2901. During this metabolism, dissimilation of pyruvate leads to the formation of energy co-factors, such as ATP and NAD+/NADH, and the level of these co-factors influences the specific growth rate of organism and hydrogen production. Our strategy for improving hydrogen production involves maximizing the ATP and NAD+ yield by modification of kinetic properties and adding new reactions in pyruvate metabolism through metabolic pathway reconstruction. Moreover,the influence of phosphoenol pyruvate carboxylase and pyruvate dehydrogenase enzyme concentration on cofactor productions was also simulated. The theoretical molar yield of ATP and NAD+ were obtained as 2.32 and 1.83mM, respectively, from 1 mM/mg of phosphoenol pyruvate (PEP) utilization. A higher yield of ATP is achieved when the PEP level reaches 5 mM/mg. This work also suggests that PEP can be considered as an alternative substrate. In conclusion, the simulation results reported in this paper can be applied to design and evaluate strategies of strain construction for optimal hydrogen yield in C. hydrogenoformans.

Life Table Studies of Leaf Roller, Diaphania pulveruleutalis (Hampson) (Lepidoptera: Pyralidae) - A Major Pest of Mulberry

Rajadurai, S.,Bhattacharya, S.,Shekhar, M.A. Korean Society of Sericultural Science 2002 International Journal of Industrial Entomology Vol.5 No.1

Mulberry leaf roller, Diaphania pulverulentalis (Hampson), is a major pest of mulberry, Morus alba. The life table construction from present investigation reveals the age specific survival $(1_{x)}$ and the age specific fecundity $(m_{x})$ of the pest. The female contributed the highest egg production $(m_{x} = 12.75)4 in the life cycle on the $27^{th}$ day and the lowest $(m_{x} = 0.8)$ on the 37$^{th}$ day of the pivotal age. The female progeny production was observed to be intensive for the first six days after the preoviposition period, beyond which it declines steadily, The fecundity of D. pulverulentalis varies between 60-140. The first female mortality within the cohort occurred 4 days after the adult emergence and mortality increased thereafter, One generation is completed in 33.08 days. The female dominated sex ratio (1: 7.18 days) was recorded.

Life table Studies of Leaf Roller, Diaphania pulvertulentalis (Hampson) (Lepidoptera: Pyralidae) 뺸 Major Pest of Mulberry

( S. Rajadurai ),( S. Bhattacharya ),( M. A. Shekhar ) 한국잠사학회 2002 International Journal of Industrial Entomology Vol.5 No.1

Current Status and Major Challenges of the Tea Industry in Sri Lanka

R. Rajadurai,D.C. Abeysinghe,유양석 한국차학회 2019 한국차학회지 Vol.25 No.2

Sri Lanka’s tea industry has always been a vital component of Sri Lanka’s overall economy. It significantly contributes to the country’s gross domestic product as the second largest agricultural industry. Sri Lanka’s tea industry is the country’s largest employer and it provided employment both directly and indirectly to over one million people. Sri Lanka is positioned 4th in the world’s tea production and Sri Lanka continues to maintain the highest world auction average price for tea. The tea industry is highly export-oriented with almost 97% of its tea being exported. Small holders contribute more than 70% of the total tea production, and the rest is largely contributed by regional processing companies. Initially developed over a period of one hundred and fifty years, the tea plantation sector was nationalized in 1972 and 1975 as part of socialist reforms. During the last two decades, the industry has undergone major changes and the industry faces a number of significant challenges. The cost of production in Sri Lanka continues to be the highest and the yield per area is the lowest among the three major tea exporting countries (India, Kenya and Sri Lanka). This paper discusses the current status and challenges faced by the Sri Lanka tea industry to ensure that it sustains continued development in the future.

Life Table Studies of Leaf Roller,Diaphania pulverulentalis (Hampson) (Lepidoptera: Pyralidae) - A Major Pest of Mulberry

S.Rajadurai,S.Bhattacharya,M.A.Shekhar 한국잠사학회 2002 International Journal of Industrial Entomology Vol.5 No.1

Online Purchasing Behavior of Green Products

Jegatheesan RAJADURAI,Vathana BATHMANATHAN,Nurnazurah AZAMI 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.6

Generation Y (Gen Y) consumers are challenging the traditional buyer-seller relationship. Sellers must adapt their approach to marketing in order to win the attention, business and loyalty of Gen Y buyers. Hence, this study aimed to examine Gen Y’s green purchasing decisions relating to online products in Malaysia. The study adopted a qualitative and quantitative approach. Items from past studies were adapted and shared with a focus group to ensure they were in line with the current trends and purchasing behavior of the Gen Y population. The items were then validated by two experts from industry and academia. A total of 113 Gen Y consumers completed the questionnaire. The data collected was analyzed using PLS-SEM software. The results of this study show that societal influence, willingness to pay higher prices for green products and government initiatives have a positive and significant effect on Gen Y online green purchasing decisions. This study supports global initiatives to create a green society by providing strong evidence of the variables that influence the Gen Y cohort’s decision to purchase green products in Malaysia and, therefore, serves as a valuable insight for producers and the government endeavoring to develop a greener society.

Intelligible Pronunciation : Focus on the Proficient L2 Speaker

Joanne Rajadurai 아시아영어교육학회 2007 The Journal of Asia TEFL Vol.4 No.1

Investigating Green Marketing Orientation Practices among Green Small and Medium Enterprises

Jegatheesan RAJADURAI,Abdul Rahman ZAHARI,Elinda ESA,Vathana BATHMANATHAN,Nur Afiqah Mohammad ISHAK 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.1

This study aims to establish the relationship between the Green Marketing Orientation (GMO) variables and the performance of Green Small and Medium Enterprises (GSMEs) across the building and energy sectors in Malaysia, using customer satisfaction as a means of performance measurement. The GMO variables examined include Greening the Process (GTP), Green Supply Chain Management (GSCM), Green Strategic Policy Initiatives (GSPI), Proactive Energy Conservation (PEC) and Green Promotion (GP). The items used to measure these variables were extracted from literature and adapted to the context of the variables based on feedback from Focus Group Discussions and Expert Opinion sessions. This study employs a survey sample of 300 respondents but only 238 completed questionnaires were returned. The results reveal that GTP, GSCM and PEC have a positive impact on Customer Satisfaction but not GSPI and GP. The findings suggest that owners or managers of GSMEs should focus on maintaining and improving GTP, GSCM and PEC in order to create greater satisfaction among their customers. The significance of this study is that it enables the creation of a framework that enables GSMEs to design a pathway towards achieving a cleaner production of goods and services in line with United Nations Sustainable Development Goals.

딥러닝을 이용한 콘크리트 구조물의 손상 탐지 및 손상유형 분류

샘라자두라이 ( Sam Rajadurai Rajagopalan ),강수태 ( Kang Su-tae ) 한국구조물진단유지관리공학회 2021 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.25 No.1

이 연구에서는 콘크리트 구조물 손상의 육안점검을 대신할 수 있고 손상 판단의 정확도를 향상시킬 수 있는 방안으로 콘크리트 구조물에 발생할 수 있는 여러 가지 손상유형을 딥러닝을 통해 분류할 수 있는 기술을 개발하고자 하였다. Pretrained Network의 하나인 AlexNet 컨볼루션 신경망을 기반으로 분석 목적에 맞게 수정하여 사용하였으며, 학습을 통해 얻어진 신경망은 비손상과 균열, 박리, 철근노출, 누수의 유형별 손상의 분류 성능검증에 대해 약 92.4%의 정확도를 확보하는 것으로 나타났다.

Current Status and Major Challenges of the Tea Industry in Sri Lanka

R,Rajadurai,D,C,Abeysinghe,Y,S,Yoo 한국차학회 2019 한국차학회지 Vol.25 No.2

스리랑카의 차 산업은 스리랑카 경제 전체의 중요한 요소이다. 차 산업은 두 번째로 큰 농업 산업으로 국내 총생산에 크게 기여하고 있으며 100 만 명이 넘는 사람을 직간접적으로 고용하고 있는 국가 최대의 고용주이다. 스리랑카는 세계 차 생산 부문에서 세계 4위를 차지하고 있으며, 세계에서 가장 높은 차 경매 평균가격을 유지하고 있다. 차 산업은 수출 지향적으로 생산되는 차의 97%를 수출하고 있다. 전체 차 생산량의 경우 소규모 소유주들이 70% 이상 기여하며 나머지는 지역 농장 재배지 회사들이 기여하고 있다. 150년이 넘는 오랜 기간에 걸쳐 개발된 차 산업은 1971년과 1975년에 사회주의 개혁의 일환으로 국영화 되었다. 지난 20년 동안 스리랑카 차 산업은 큰 변화를 겪어 왔으며 현재 수많은 문제를 직면하고 있다. 주요 3대 홍차 수출국 (인디아, 케냐, 스리랑카) 중 생산비가 가장 높은 수준이며 단위면적 당 수확량은 가장 낮은 수준이다. 본 논문은 스리랑카 차 산업이 직면한 현황과 과제를 논의함으로써 미래의 지속적인 발전을 이루는 것을 목적으로 한다. Sri Lanka’s tea industry has always been a vital component of Sri Lanka’s overall economy. It significantly contributes to the country’s gross domestic product as the second largest agricultural industry. Sri Lanka’s tea industry is the country’s largest employer and it provided employment both directly and indirectly to over one million people. Sri Lanka is positioned 4th in the world’s tea production and Sri Lanka continues to maintain the highest world auction average price for tea. The tea industry is highly export-oriented with almost 97% of its tea being exported. Small holders contribute more than 70% of the total tea production, and the rest is largely contributed by regional processing companies. Initially developed over a period of one hundred and fifty years, the tea plantation sector was nationalized in 1972 and 1975 as part of socialist reforms. During the last two decades, the industry has undergone major changes and the industry faces a number of significant challenges. The cost of production in Sri Lanka continues to be the highest and the yield per area is the lowest among the three major tea exporting countries (India, Kenya and Sri Lanka). This paper discusses the current status and challenges faced by the Sri Lanka tea industry to ensure that it sustains continued development in the future.