Crystal Structure Analysis of N,N′-bis(3-chloro-2-methylsalicylidene)-1,4- butanediamine

P. Sharmila, R. Rajesh, R. Venkatesan2, Jagadeesan Ganapathy, and S. Aravindhan 조선대학교 기초과학연구원 2016 조선자연과학논문집 Vol.9 No.4

The crystal structure of the saliciline derivatives N,N′-bis(3-chloro-2-methylsalicylidene)-1,4-butanediamine (C20H22Cl2N2O2) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the triclinic space group Pī with unit cell dimension a= 4.6085(3) Å, b=5.9747(3) Å and c= 5.9747(3) Å [α=83.889 (4)°, β= 86.744(5)° and γ= 82.085(5)°]. The title compound is essentially planar conformation. The compound lies across a crystallographic inversion centre and adopts E configurations with respect to the C-N bonds. The crystal packing of the molecules of compound is stabilized through weak O-H...N intra molecular interactions Keywords: Chromene; Schiff Base Ligand; Single Crystal Structure; X-ray Diffraction

Combination of Nano-Hydroxyapatite with Stem Cells for Bone Tissue Engineering

Venkatesan, Jayachandran,Lowe, Baboucarr,Anil, Sukumaran,Kim, Se-Kwon,Shim, Min Suk American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.9

<P>Tissue engineering seeks to exploit functional biomaterials and engineer them to serve as artificial templates that promote the regeneration of tissues and damaged organs. Engineered scaffold materials recapitulate the extracellular matrix and provide cells with information essential for tissue development. Nanotechnologies make use of the material at the nanoscale for targeted interactions at molecular levels and deliver biochemical cues for cell growth required for tissue formation. In bone tissue engineering, nano-hydroxyapatite (nHA), which is a calcium phosphate-based material, is extensively used as a bone defect substitute to mimic the natural bioceramic portion of bone. nHA can be functionalized in the form of composite scaffolds along with other polymers, ceramic, and growth factors to enable bone tissue regeneration. In addition, the material directs stem cell differentiation into specific lineages. This stem cell-based therapy is a prominent approach in organ development and tissue regeneration. Here, we examine nHA interactions with stem cells in the form of designed scaffolds and offer important considerations about the fundamental challenges and prospects for its application in bone tissue engineering.</P>

Deoxyrhapontigenin, a Natural Stilbene Derivative Isolated From <i>Rheum undulatum</i> L. Induces Endoplasmic Reticulum Stress–Mediated Apoptosis in Human Breast Cancer Cells

Venkatesan, Thamizhiniyan,Jeong, Min-Ji,Choi, Young-Woong,Park, Eun-Jin,El-Desouky, Samy Korany,Kim, Young-Kyoon SAGE Publications 2016 Integrative cancer therapies Vol.15 No.4

<P>Although current chemotherapeutic agents are active at the beginning of therapy, the most common risk is the development of resistance during later stages in almost all cancer types including breast cancer. Hence, investigation of novel drugs is still a priority goal for cancer treatment. The objective of the present study is to investigate the anticancer effect of a derivative of stilbene, deoxyrhapontigenin (DR) isolated from <I>Rheum undulatum</I> L. root extracts against the chemoresistant MCF-7/adr and its parental MCF-7 human breast cancer cells. The morphological images indicate that DR induces an extensive cytoplasmic vacuolation in breast cancer cells. Mechanistic investigations revealed that DR treatment causes endoplasmic reticulum (ER) dilation and upregulated the expression of ER stress markers GRP78, IRE1α, eIF2α, CHOP, JNK, and p38. Subsequently, we also identified that DR increases the levels of apoptotic fragment of PARP (89 kDa) in breast cancer cells. Blocking the expression of one of the components of the ER stress–mediated apoptosis pathway, CHOP using siRNA significantly decreased DR-induced apoptotic cleavage of PARP. In summary, the present study suggests that the induction of ER stress–mediated apoptosis by DR may account for its cytotoxic effects in human breast cancer cells.</P>

Low temperature hydrogen sensing using reduced graphene oxide and tin oxide nanoflowers based hybrid structure

Venkatesan, A,Rathi, Servin,Lee, In-Yeal,Park, Jinwoo,Lim, Dongsuk,Kim, Gil-Ho,Kannan, E S Institute of Physics 2016 Semiconductor science and technology Vol.31 No.12

<P>In this paper, we have demonstrated a low temperature hydrogen (H<SUB>2</SUB>) sensor based on reduced graphene oxide (rGO) and tin oxide nanoflowers (SnO<SUB>2</SUB> NFs) hybrid composite film. The addition of SnO<SUB>2</SUB> NFs into rGO solution inhibits irreversible restacking and agglomeration of rGO and increases the active surface area for interaction with H<SUB>2</SUB>. This rGO-SnO<SUB>2</SUB> NFs hybrid film sensor showed an excellent response to H<SUB>2</SUB> at 60 °C at 200 ppm with an improvement of 126% compared to pure rGO which was used as a control sample. The sensor also showed good response and recovery time in comparison to pure rGO film. The highly improved H<SUB>2</SUB> sensing characteristics of rGO-SnO<SUB>2</SUB> NFs hybrid are due to its (a) unique structural geometry that increased the surface area for H<SUB>2</SUB> adsorption, and (b) change in the width of depletion layer at the interface due to H<SUB>2</SUB> interaction.</P>

Dry and wet lab analysis on benzofused heterocyclic compounds as effective corrosion inhibitors for mild steel in acidic medium

Venkatesan Hemapriya,Mayakrishnan Prabakaran,Kandasamy Parameswari,Subramaniyan Chitra,김승현,정일민 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.40 No.-

The influence of two benzofused heterocyclic compounds, namely 2-phenylquinazolin-4(3H)-one(PQO)and 2-phenyl-4H-benzo[d]oxazin-4-one(POO) in controlling mild steel corrosion in 1 M H2SO4 solutionwas investigated using gravimetric and electrochemical methods. The experimental results revealedthat both the inhibitors inhibit corrosion and their inhibition efficiency follows the order PQO > POO. Amixed mode of inhibition from polarization and a charge transfer mechanism from impedance study inthe absence and presence of inhibitors were found. The passive film formed on the mild steel surface wascharacterized using SEM-EDX. Quantum chemical parameters derived using DFT performed at B3LYP/6-31G(d, p) level were used to correlate the molecular structure.

Chemical Modification of Nucleic Acids toward Functional Nucleic Acid Systems

Venkatesan, Natarajan,Seo, Young-Jun,Bang, Eun-Kyoung,Park, Sun-Min,Lee, Yoon-Suk,Kim, Byeang-Hyean Korean Chemical Society 2006 Bulletin of the Korean Chemical Society Vol.27 No.5

Nucleic acids are virtually omnipresent; they exist in every living being. These macromolecules constitute the most important genetic storage material: the genes. Genes are conserved throughout the evolution of all living beings; they are transmitted from the parents to their offspring. Many interdisciplinary research groups are interested in modifying nucleic acids for use in a wider variety of applications. These modified oligonucleotides are used in many diverse fields, including diagnostics, detection, and therapeutics. In this account, we summarize our research efforts related to modified nucleic acid systems. First, we discuss our syntheses of modified oligonucleotides containing fluorescent tags for use as molecular probes (molecular beacons) to detect single-nucleotide polymorphisim (SNP) in nucleic acids and to distinguish between the B and Z forms of DNA. We also describe our research efforts into oligonucleotides functionalized with steroid derivatives to enhance their cell permeability, and the synthesis of several calix[4]arene-oligonucleotide conjugates possessing the ability to form defined triplexes. In addition, we have performed systematic studies to have an understanding about the functional groups necessary for a given nucleoside to behave as an organo or hydrogelator. The aggregation properties of a number of nucleoside-based phospholipids have been examined in different solvents; some of these derivatives are potential candidates for use as nucleoside-based liposomes. Finally, we also describe our research efforts toward the preparation of isoxazole- and isoxazoline-containing nucleoside derivatives and the determination of their antiviral activities.

Phytochemicals That Regulate Neurodegenerative Disease by Targeting Neurotrophins: A Comprehensive Review

Venkatesan, Ramu,Ji, Eunhee,Kim, Sun Yeou Hindawi Publishing Corporation 2015 BioMed research international Vol.2015 No.-

<P>Alzheimer's disease (AD), characterized by progressive dementia and deterioration of cognitive function, is an unsolved social and medical problem. Age, nutrition, and toxins are the most common causes of AD. However, currently no credible treatment is available for AD. Traditional herbs and phytochemicals may delay its onset and slow its progression and also allow recovery by targeting multiple pathological causes by antioxidative, anti-inflammatory, and antiamyloidogenic properties. They also regulate mitochondrial stress, apoptotic factors, free radical scavenging system, and neurotrophic factors. Neurotrophins such as BDNF, NGF, NT3, and NT4/5 play a vital role in neuronal and nonneuronal responses to AD. Neurotrophins depletion accelerates the progression of AD and therefore, replacing such neurotrophins may be a potential treatment for neurodegenerative disease. Here, we review the phytochemicals that mediate the signaling pathways involved in neuroprotection specifically neurotrophin-mediated activation of Trk receptors and members of p75<SUP>NTR</SUP> superfamily. We focus on representative phenolic derivatives, iridoid glycosides, terpenoids, alkaloids, and steroidal saponins as regulators of neurotrophin-mediated neuroprotection. Although these phytochemicals have attracted attention owing to their <I>in vitro</I> neurotrophin potentiating activity, their <I>in vivo</I> and clinical efficacy trials has yet to be established. Therefore, further research is necessary to prove the neuroprotective effects in preclinical models and in humans. </P>

Pinus radiata bark extract induces caspase-independent apoptosis-like cell death in MCF-7 human breast cancer cells

Venkatesan, T.,Choi, Y. W.,Mun, S. P.,Kim, Y. K. Springer Science + Business Media 2016 Cell biology and toxicology Vol.32 No.5

<P>In the present study, we investigated the anticancer activity of Pinus radiata bark extract (PRE) against MCF-7 human breast cancer cells. First, we observed that PRE induces potent cytotoxic effects in MCF-7 cells. The cell death had features of cytoplasmic vacuolation, plasma membrane permeabilization, chromatin condensation, phosphatidylserine externalization, absence of executioner caspase activation, insensitivity to z-VAD-fmk (caspase inhibitor), increased accumulation of autophagic markers, and lysosomal membrane permeabilization (LMP). Both the inhibition of early stage autophagy flux and lysosomal cathepsins did not improve cell viability. The antioxidant, n-acetylcysteine, and the iron chelator, deferoxamine, failed to restore the lysosomal integrity indicating that PRE-induced LMP is independent of oxidative stress. This was corroborated with the absence of enhanced ROS production in PRE-treated cells. Chelation of both intracellular calcium and zinc promotes PRE-induced LMP. Geranylgeranylacetone, an inducer of Hsp70 expression, also had no significant protective effect on PRE-induced LMP. Moreover, we found that PRE induces endoplasmic reticulum (ER) stress and mitochondrial membrane depolarization in MCF-7 cells. The ER stress inhibitor, 4-PBA, did not restore the mitochondrial membrane integrity, whereas cathepsin inhibitors demonstrated significant protective effects. Collectively, our results suggest that PRE induces an autophagic block, LMP, ER stress, and mitochondrial dysfunction in MCF-7 cells. However, further studies are clearly warranted to explore the exact mechanism behind the anticancer activity of PRE in MCF-7 human breast cancer cells.</P>

EP Based PSO Method for Solving Multi Area Unit Commitment Problem with Import and Export Constraints

Venkatesan, K.,Selvakumar, G.,Rajan, C. Christober Asir The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

This paper presents a new approach to solve the multi area unit commitment problem (MAUCP) using an evolutionary programming based particle swarm optimization (EPPSO) method. The objective of this paper is to determine the optimal or near optimal commitment schedule for generating units located in multiple areas that are interconnected via tie lines. The evolutionary programming based particle swarm optimization method is used to solve multi area unit commitment problem, allocated generation for each area and find the operating cost of generation for each hour. Joint operation of generation resources can result in significant operational cost savings. Power transfer between the areas through the tie lines depends upon the operating cost of generation at each hour and tie line transfer limits. Case study of four areas with different load pattern each containing 7 units (NTPS) and 26 units connected via tie lines have been taken for analysis. Numerical results showed comparing the operating cost using evolutionary programming-based particle swarm optimization method with conventional dynamic programming (DP), evolutionary programming (EP), and particle swarm optimization (PSO) method. Experimental results show that the application of this evolutionary programming based particle swarm optimization method has the potential to solve multi area unit commitment problem with lesser computation time.

Molybdenum disulfide nanoparticles decorated reduced graphene oxide: highly sensitive and selective hydrogen sensor

Venkatesan, A,Rathi, Servin,Lee, In-yeal,Park, Jinwoo,Lim, Dongsuk,Kang, Moonshik,Joh, Han-Ik,Kim, Gil-Ho,Kannan, E S IOP Pub 2017 Nanotechnology Vol.28 No.36

<P>In this work, we report on the hydrogen (H<SUB>2</SUB>) sensing behavior of reduced graphene oxide (RGO)/molybdenum disulfide (MoS<SUB>2</SUB>) nano particles (NPs) based composite film. The RGO/MoS<SUB>2</SUB> composite exhibited a highly enhanced H<SUB>2</SUB> response (∼15.6%) for 200 ppm at an operating temperature of 60 °C. Furthermore, the RGO/MoS<SUB>2</SUB> composite showed excellent selectivity to H<SUB>2</SUB> with respect to ammonia (NH<SUB>3</SUB>) and nitric oxide (NO) which are highly reactive gas species. The composite’s response to H<SUB>2</SUB> is 2.9 times higher than that of NH<SUB>3</SUB> whereas for NO it is 3.5. This highly improved H<SUB>2</SUB> sensing response and selectivity of RGO/MoS<SUB>2</SUB> at low operating temperatures were attributed to the structural integration of MoS<SUB>2</SUB> nanoparticles in the nanochannels and pores in the RGO layer.</P>