Site directed mutagenesis and CBM engineering of Ce15A (Thermotoga maritima)

( Arumugam Mahadevan Shobana ),( Dae Seok Lee ),( Hyun Joo Kim ),( Hyeun Jong Bae ) 韓國木材工學會 2008 한국목재공학회 학술발표논문집 Vol.2008 No.-

Structural, Electrochemical, DNA Binding and Cleavage Properties of Nickel(II) Complex [Ni(H2biim)2(H2O)2]2+ of 2,2'-Biimidazole

Arumugam Jayamani,Vijayan Thamilarasan,Venketasan Ganesan,Nallathambi Sengottuvelan 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.12

A nickel(II) complex [Ni(H2biim)2(H2O)2](ClO4)2·H2O (1) of biimidazole ligand has been synthesized and characterized (Where H2biim = 2,2'-biimidazole). The single crystal X-ray diffraction of the complex shows a dimeric structure with six coordinated psudo-octahedral geometry. The cyclic voltammograms of complex exhibited one quasireversible reduction wave (Epc = −0.61 V) and an irreversible oxidation wave (Epa = 1.28 V) in DMF solution. The interaction of the complex with Calf-Thymus DNA (CT-DNA) has been investigated by absorption and fluorescence spectroscopy. The complex is an avid DNA binder with a binding constant value of 1.03 × 105 M−1. The results suggest that the nickel(II) complex bind to CT-DNA via intercalative mode and can quench the fluorescence intensity of EB bind to CT-DNA with Kapp value of 3.2 × 105 M−1. The complex also shown efficient oxidative cleavage of supercoiled pBR322 DNA in the presence of hydrogen peroxide as oxidizing agent. The DNA cleavage by complex in presence of quenchers; viz. DMSO, KI, NaN3 and EDTA reveals that hydroxyl radical or singlet oxygen mechanism is involved. The complex showed invitro antimicrobial activity against four bacteria and two fungi. The antimicrobial activity was nearer to that of standard drugs and greater than that of the free ligand.

Quantum dots attached to graphene oxide for sensitive detection of ascorbic acid in aqueous solutions

Arumugam, Nandhini,Kim, JongSung Elsevier 2018 Materials science & engineering. C, Materials for Vol.92 No.-

<P><B>Abstract</B></P> <P>Water-soluble fluorescent carboxyl-functionalized CdSe-ZnS quantum dots (QDs) were immobilized on graphene oxide (GO) and used for sensitive detection of ascorbic acid in aqueous solutions. QDs were attached to the surface of graphene oxide using the EDC/NHS-sulfo coupling reaction. Ascorbic acid is known as an antioxidant. It plays a crucial role in health maintenance, bio synthetic pathways such as formation of collagen and regulates immune system. The photoluminescence (PL) intensity of as-prepared GO-QD hybrids in water was quenched by ascorbic acid at ambient temperature. Based on this photoluminescence quenching phenomenon, a simple, rapid, and sensitive procedure is developed. In this study we are successful in detecting ascorbic acid due to its biological significance and the limit of detection is 568 pM.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sensing platform based on quantum dots attached to graphene oxide (GO) was established. </LI> <LI> The preparation of GO-QD hybrids is simple and inexpensive. </LI> <LI> As-prepared GO-QD hybrids are successful in detecting ascorbic acid. </LI> <LI> Simple and sensitive detection of ascorbic acid at picomolar level </LI> </UL> </P>

Automated Strawberry Flower Detection for Yield Estimation using Machine Vision

( Arumugam Kalaikannan ),( Won Suk Lee ),( Natalia Peres ),( Clyde Fraisse ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Strawberry is an important horticultural crop in the U.S. Strawberry, which ranks 8th in produce and 4th in fruit with a total value of $2.4 billion annually. Since strawberries are manually harvested and labor shortage is a major concern, yield predictions become extremely important for scheduling labors in harvesting and other field operations as well as marketing. For efficient use of labor resources in harvesting and other operations, strawberry growers in the U.S. will need reliable yield prediction models by utilizing a more feasible and efficient method to count the number of flowers in their fields. Images were acquired from a strawberry field using a consumer grade digital color camera at various working distances, angles and lighting conditions. Various image processing techniques were used to develop automated flower counting algorithms from the images. An accuracy of 88% was achieved by the computer vision algorithm on validation dataset. The number of strawberry flowers obtained from this algorithm will be used to develop a strawberry yield prediction model, which eventually will be used for efficient labor management for harvesting and marketing to increase yield and profit of the strawberry growers.

Novel Switching Table for Direct Torque Controlled Permanent Magnet Synchronous Motors to Reduce Torque Ripple

Arumugam, Sivaprakasam,Thathan, Manigandan The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

The Direct Torque Control (DTC) technique for Permanent Magnet Synchronous Motors (PMSM) is receiving increased attention due to its simplicity and robust dynamic response when compared with other control techniques. The classical switching table based DTC results in large flux and torque ripples in the motors. Several studies have been reported in the literature on classical DTC. However, there are only limited studies that actually discuss or evaluate the classical DTC. This paper proposes, novel switching table / DTC methods for PMSMs to reduce torque ripples. In this paper, two DTC schemes are proposed. The six sector and twelve sector methodology is considered in DTC scheme I and DTC scheme II, respectively. In both DTC schemes a simple modification is made to the classical DTC structure. The two level inverter available in the classical DTC is eliminated by replacing it with a three level Neutral Point Clamped (NPC) inverter. To further improve the performance of the proposed DTC scheme I, the available 27 voltage vectors are allowed to form different groups of voltage vectors such as Large - Zero (LZ), Medium - Zero (MZ) and Small - Zero (SZ), where as in DTC scheme II, all of the voltage vectors are considered to form a switching table. Based on these groups, a novel switching table is proposed. The proposed DTC schemes are comparatively investigated with the classical DTC and existing literatures through theory analysis and computer simulations. The superiority of the proposed DTC method is also confirmed by experimental results. It can be observed that the proposed techniques can significantly reduces the torque ripples and improves the quality of current waveform when compared with traditional and existing methods.

Quantitative evaluation of ABC transporter-mediated drug resistance based on the determination of the anticancer activity of camptothecin against breast cancer stem cells using TIRF

Arumugam, Parthasarathy,Song, Joon Myong Oxford University Press 2016 Integrative biology Vol.8 No.6

<P>Elevated expression of drug efflux pumps such as multidrug resistant protein-1 (MDR1/ABCB1) and multidrug resistance associated protein-1 (MRP1/ABCC1) in cancer stem cells (CSCs) among a bulky tumor cell population was attributed to drug resistance. For the first time, we have quantitatively evaluated the cytotoxic profile of camptothecin (CPT) against the CSC. In the present study, a Qdot based total internal reflection fluorescence (TIRF) detection system effectively interpreted that drug resistance to CPT was reduced in the CSC under ABCB1 inhibited conditions. This study revealed that quantitative finding of the EC50 value for apoptosis and necrosis in correlation with the ABC inhibitor and CSC population using TIRF could provide more details of the anti-cancer efficacy of chemotherapeutic agents.</P>

The Impact of Property Management Services on Tenants’ Satisfaction with Industrial Buildings

Arumugam Seetharaman,A. S. Saravanan,Nitin Patwa,Jiann Ming Bey 한국유통과학회 2017 The Journal of Asian Finance, Economics and Busine Vol.4 No.3

In the current competitive marketplace of real estate business, tenant satisfaction measurement is one of the important indicators to monitor competitiveness in industrial property development. It has become an industry standard to measure tenant satisfaction, commonly called customer satisfaction. Customer satisfaction has become the widely used metric to manage customer loyalty (Keiningham, Gupta, Aksoy, & Buoye, 2014). The aim of this research is to determine the impact of property management services on tenants’ satisfaction with the three identified variables i.e. facility management, perceived quality and lease management. Structural equation modeling (SEM) is applied to build constructs and test the hypotheses with the collected survey samples. Of the three variables, facility management is the most influential factor that leads to tenant satisfaction with industrial buildings. Next, perceived quality is another important factor that contributes to tenants’ pleasure. Compared with these two, lease management fares worse, having the least extensive effect on tenant satisfaction, and could be disregarded. The ultimate impact of tenant satisfaction is about tenant retention and recommendation. The overall findings of this research will potentially help real estate developers to develop a better property management system, leasing program and tenant retention strategy.

Knockdown of clusterin alters mitochondrial dynamics, facilitates necrosis in camptothecin-induced cancer stem cells

Arumugam, P.,Samson, A.,Ki, J.,Song, J. M. Springer Science + Business Media 2017 Cell biology and toxicology Vol.33 No.3

<P>The existence of a well-established drug resistance mechanism in cancer stem cells (CSC) complicates the cancer treatment. Clusterin (CLU) plays a key role in maintaining the integrity of endoplasmic reticulum (ER) during drug-induced stress. Hence, silencing the CLU could significantly reduce the inherent drug resistance mechanism of CSC. The combination of drug-induced cytotoxicity, as well as the suppression of drug resistance in CSC, could circumvent the recurrence capability of the tumor. In the present study, camptothecin (CPT)-induced apoptosis and necrosis in CSC with and without siCLU treatment were simultaneously measured using Qdot-based total internal reflection fluorescence microscope (TIRF). In addition, to elucidate the mechanism of CPT-induced cytotoxicity in CLU-suppressed CSC, expression of Bcl-2, Bax, Bak, and PARP and mitochondrial permeability transition pore (MPTP) were studied. EC50 values of CPT-induced apoptosis and necrosis were significantly reduced (p < 0.01) in CLU-suppressed MCF-7 and CSC. Significantly increased MPTP (p < 0.001) and cytosolic Ca2+ (p < 0.001) were observed in CPT-treated CLU-suppressed CSC as compared to the normal CSC. Elevated expression of Bax, Bak, and cleaved PARP and reduced expression of Bcl-2 and cytosolic ATP were observed in CPT-treated CLU-suppressed CSC. Observed results indicate that silencing the expression of CLU could improve the anticancer efficacy of CPT at 128.4-nM concentration by equally inducing necrotic signals along with apoptosis. Furthermore, the developed high content TIRF assay based on the CLU-suppressed CSC could be an ideal and beneficial tool for rapidly analyzing the cytotoxicity of anti-cancer agents.</P>

Notch signaling and neuronal death in stroke

Arumugam, Thiruma V.,Baik, Sang-Ha,Balaganapathy, Priyanka,Sobey, Christopher G.,Mattson, Mark P.,Jo, Dong-Gyu Elsevier 2018 Progress in neurobiology Vol.165 No.-

<P><B>Abstract</B></P> <P>Ischemic stroke is a leading cause of morbidity and death, with the outcome largely determined by the amount of hypoxia-related neuronal death in the affected brain regions. Cerebral ischemia and hypoxia activate the Notch1 signaling pathway and four prominent interacting pathways (NF-κB, p53, HIF-1α and Pin1) that converge on a conserved DNA-associated nuclear multi-protein complex, which controls the expression of genes that can determine the fate of neurons. When neurons experience a moderate level of ischemic insult, the nuclear multi-protein complex up-regulates adaptive stress response genes encoding proteins that promote neuronal survival, but when ischemia is more severe the nuclear multi-protein complex induces genes encoding proteins that trigger and execute a neuronal death program. We propose that the nuclear multi-protein transcriptional complex is a molecular mediator of neuronal hormesis and a target for therapeutic intervention in stroke.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We review the roles of Notch in the neuropathology of ischemic stroke. </LI> <LI> We discuss the mechanisms for how Notch interacts with other gene transcription regulators such as HIF-1α, NF-κB, p53 and Pin1 following a stroke. </LI> <LI> We introduce a novel concept of a multi-protein complex which controls the expression of genes that determine the fate of neurons in stroke. </LI> <LI> We discuss if and how the multi-protein complex may regulate neuronal plasticity and resilience during the remodeling phase following stroke. </LI> <LI> We conclude with a perspective on how this research may lead to novel approaches for clinical intervention in ischemic stroke. </LI> </UL> </P>

P-907 : Structural and optical properties of ZnO nanowires grown by rapid thermal chemical vapour deposition

( Arumugam Sekar ),김상훈,이석,라현욱,한윤봉 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.2

Catalysts free ZnO nanowires were grown on Si (100) substrates using rapid thermal chemical vapour deposition (RTCVD) at various growth conditions using metallic Zn powder as the source material. Further examinations of the growth conditions of ZnO nanowires observed in electron microscopy implied that the ZnO nanowire growth was favoured by high flow rate of oxygen gas supply and high growth temperature (Tg = 600 C). The structural, surface morphology and optical properties of ZnO nanowires were systematically investigated by means of x-ray diffraction, Field Emission Scanning Electron Microscope (FE-SEM) and Photoluminescence (PL) respectively. Photoluminescence spectroscopy showed that nanowires have better optical qualities. These results indicate that one can obtain ZnO nanowires by selecting the growth temperature and oxygen flow rate.