Combined ozone, photo, and electrocoagulation technologies-An innovative technique for treatment of distillery industrial wastewater

Perumal Asaithambi,Mamuye Busier Yesuf,Rajendran Govindarajan,Subramaniapillai Niju,Selvakumar Periyasamy,Zeinu Ahmed Rabba,T. Pandiyarajan,Abudukeremu Kadier,Dhakshnamoorthy Mani,Esayas Alemayehu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.2

Fluoropolymer synthesis and its application as a mold material in UV-nano-imprint lithography process.

Perumal, Jayakumar,Kim, Dong-Pyo,Lee, Jae-Jong American Scientific Publishers 2008 Journal of Nanoscience and Nanotechnology Vol.8 No.10

<P>In our present work, we report the synthesis of a novel, highly photosensitive photocurable methacrylate functionalized perfluoropolyether (fluoropolymer) by grafting methacrylate functional group onto the backbone of perfluoropolyether chain. Reaction mechanism for the synthesis of the oligomer has been clearly described in this article. Dihydroxy terminated perfluoropolyether (PFPE-diol) monomer was made photocurable by carrying out its reaction with ethyl isocyanato methacrylate (EIM) by a simple addition reaction. The product was characterized by NMR and FT-IR analysis. The synthesized polymeric material has potential application in soft lithographic process, as a viable option for PDMS (polydimethylsiloxane). Mold materials made from fluoropolymer have higher modulus, when compared to PDMS and posses better pattern relief property than rigid materials such as, quartz. In particular this fluoropolymer can be used as stamping material in nano fabrication, especially in UV-based Nano-imprinting lithographic (NIL) process.</P>

Adhesion force measurement between the stamp and the resin in ultraviolet nanoimprint lithography—an investigative approach

Perumal, Jayakumar,Yoon, Tae Ho,Jang, Hwan Soo,Lee, Jae Jong,Kim, Dong Pyo IOP Pub 2009 Nanotechnology Vol.20 No.5

<P>In the ultraviolet nanoimprint lithography (UV-NIL) process, the surface interaction between the mold and the resist is essential along with molecularly clean separation of the mold from the surface of the cured resist for repeated use of the mold. In our present study, various mold–resin combinations have been examined by a tensile strength method to determine the adhesion force between a mold with a relief pattern and a photocurable resin. The adhesion force of polymer molds of the fluorine-containing polymers perfluoropolyether dimethacrylate (PFPE) and polydimethylsiloxane (PDMS) were compared to those of hard molds such as Si and quartz against several commercial UV-NIL resins. Eventually, PFPE with higher molecular weight—AMONIL—was found to be an excellent UV-NIL mold–resin combination with the lowest adhesion force per unit area (20 kPa). In particular, the 36-fold repeated imprinting with a high molecular weight PFPE mold showed only a slight increase of adhesion force by 36 kPa with molecularly clean release from the AMONIL resin, whereas a surface-modified PDMS mold revealed highly increased adhesion from an initial 20 kPa to 120 kPa after repeated use. </P>

Highly flexible memristive devices based on MoS₂ quantum dots sandwiched between PMSSQ layers

Perumal Veeramalai, Chandrasekar,Li, Fushan,Guo, Tailiang,Kim, Tae Whan The Royal Society of Chemistry 2019 Dalton Transactions Vol.48 No.7

<P>This paper reports a facile, cost effective method that uses an aqueous hydrothermal process for synthesizing two-dimensional molybdenum disulphide (MoS2) monolayer quantum dots (QDs) and their potential applications in flexible memristive devices. High-resolution transmission electron microscopy and atomic force microscopy images confirmed that the diameters of the synthesized MoS2 QDs with irregular shapes were in the range between 3 and 6 nm; their thicknesses were confirmed to lie between 1.0 and 0.8 nm, a clear indication that a monolayer of MoS2 QDs had been synthesized. Photoluminescence (PL) and time-resolved PL spectra of the MoS2 QDs revealed a strong emission in the blue region with a slower decay constant. Memristive devices fabricated by incorporating MoS2 QDs between poly(methylsilsesquioxane) ultrathin layers, which had been deposited on poly(ethylene terephthalate), demonstrated a high ON-OFF current ratio of ∼10<SUP>4</SUP>, stable retention, and excellent endurance in the relaxed state; these devices were also demonstrated to function properly during bending and in a bent state. The flexible memristive devices demonstrated an OFF state with a very low current of 10<SUP>−6</SUP> A. These results clearly show that ultrathin two-dimensional QDs have promising applications in high-performance flexible memristive devices.</P>

Consideration of bulk concentration change in transient current of rotating disc electrode for E’ reaction (quasi- reversible): Theoretical simulation and experimental validation

( Perumal Silambarasan ),심왕근,( G. Muthuraman ),문일식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

In the rotating disc electrode transient current, the bulk concentration considered as constant due to the non-electrolyzed solution. But, change in bulk concentration occurred in many paired electrolysis process with electrolysis time that is used for many applications. In this work, the transient current and concentration change in the rotating disc electrode (RDE) system is explained by solving the convection and diffusion equation for a quasi- reversible electron transfer. The mathematical models are solved by applying orthogonal collocation method. This approach enables us the current response and concentration change with electrolysis time. Experimental results compared with the theoretically simulated data. A good correlation found between the current and the RDE system. The possible expression derived in the present work for bulk concentration change can be used for continuous electrolysis system.

Miniature Inverted-repeat Transposable Elements (MITEs) as Valuable Genomic Resources for the Evolution and Breeding of Brassica Crops

( Perumal Sampath ),( Tae Jin Yang ) 한국육종학회 2014 Plant Breeding and Biotechnology Vol.2 No.4

Transposable elements (TEs) play important roles in structural and functional diversification, genome enlargement, and speciation in plant genome. Their derivatives or small non-autonomous TEs play important roles in the alteration of homologous genes by epigenetic control or structural modification. The miniature inverted-repeat transposable element (MITE) is one of the representative non-autonomous class II TEs. MITEs include high copy members that are widely distributed and in close association with genic regions, which make MITEs useful targets and resources for in-depth understanding of genome evolution, as well as practical applications in molecular breeding. Here, we discuss the important features of MITEs, such as the identification tools of a novel MITE family, structural characterization, distribution pattern analysis, and impact on evolution in highly duplicated Brassica genome. We show the characteristics, copy numbers, and distribution patterns of 20 novel MITE families, and represent their putative roles in the evolution of the triplicated Brassica genome. We also introduce our MITE database, and discuss the utility of MITEs for developing MITE-derived markers that are useful for molecular breeding of Brassica crops.

Analysis and prediction of ultimate strength of high-strength SFRC plates under in-plane and transverse loads

Perumal, Ramadoss,Palanivel, S. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.6

Plates are most widely used in the hulls of floating concrete structures, bridge decks, walls of off-shore structures and liquid storage tanks. A method of analysis is presented for the determination of load-deflection response and ultimate strength of high-strength steel fiber reinforced concrete (HSSFRC) plates simply supported on all four edges and subjected to combined action of external compressive in-plane and transverse loads. The behavior of HSSFRC plate specimens subjected to combined uniaxial in-plane and transverse loads was investigated. The proposed analytical method is compared to the physical test results, and shows good agreement. To predict the constitutive behavior of HSSFRC in compression, a non-dimensional characteristic equation was proposed and found to give reasonable accuracy.

Continuous potentiometric sensor for electrogenerated mediator in solution: rationalization by the RDE and flow cell methods

( Perumal Silambarasan ),( Govindan Muthuraman ),문일식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Very recently, an in-situ determination of electron mediators’ quantification was developed by potentiometric sensor method. Here in, a rationalization of potentiometric sensor by RDE (rotating disc electrode) and flow cell methods were optimized. First, electrochemical generation of [Co(I)(CN)5]4- in 10 M KOH solution was done by Nafion324 membrane divided electrochemical cell. The electrogenerated solution monitored by current and potential using RDE and flow cell with different RPM (rotation per minute) and flow rate by cyclic voltammetry (CV) method. By comparing the peak potential and peak current change, validation of a suitable method was derived for potentiometric sensor in determination of electrogenerated electron mediator in solution.

Interaction of Zwitterionic and Ionic Monomers with Graphene Surfaces

Perumal, Suguna,Raji, Atchudan,Cheong, In Woo American Chemical Society 2018 Langmuir Vol.34 No.23

<P>Measurement of the interaction force between two materials provides important information on various properties, such as adsorption, binding, or compatibility for coatings, adhesion, and composites. The interaction forces of zwitterionic and ionic monomers with graphite platelets (G) and reduced graphene oxide (rGO) surfaces were systematically investigated by atomic force microscopy (AFM) in air and water. The monomers examined were 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate (MPC), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBE), [2-(acryloyloxy)ethyl]trimethylammonium chloride (ATC), and 2-methyl-2-propene-1-sulfonic acid sodium (MSS). The AFM studies revealed that MSS and SBE monomers with sulfonate units have stronger interaction forces with G surface in air and that MPC and ATC monomers with quaternary ammonium units have higher interaction forces in water. In the case of rGO surface, the monomers with quaternary ammonium units showed stronger interactions regardless of the medium. These interactions could be rationalized by the interaction mechanism between the monomers with graphene surfaces, such as cation−π for MPC and ATC and anion−π for MSS and SBE. Overall, cation−π interactions were effective in water, whereas anion−π interactions are effective in air with G surface. The adhesion values of MPC, SBE, ATC, and MSS on rGO were lower than the values measured on G surface. Among the monomers, MPC showed the highest dispersibility for aqueous graphene dispersions. Further, the adsorption of MPC on G and rGO surfaces was verified by high-resolution transmission electron microscopy and X-ray diffraction patterns.</P> [FIG OMISSION]</BR>

PTEN inactivation induces epithelial-mesenchymal transition and metastasis by intranuclear translocation of β-catenin and snail/slug in non-small cell lung carcinoma cells

Perumal, Elumalai,So Youn, Kim,Sun, Shin,Seung-Hyun, Jung,Suji, Min,Jieying, Liu,Yeun-Jun, Chung Elsevier 2019 Lung cancer Vol.130 No.-

<P><B>Abstract</B></P> <P><B>Objective</B></P> <P>Epithelial-mesenchymal transition (EMT) is the key event in distant metastasis of diverse tumors including lung cancer. Recent evidence suggests the involvement of phosphatase and tensin homolog (PTEN) in EMT phenotypes. However, the molecular mechanism of EMT induced by PTEN inactivation is not clear in lung cancer. We aimed to investigate the role of PTEN inactivation in acquisition of EMT in lung cancer cells.</P> <P><B>Methods</B></P> <P>We knocked out the PTEN in PTEN proficient lung cancer cells lines (A549 and NCI-H460) using CRISPR/Cas-9 system and observed the growth, EMT phenotypes, and EMT related molecules. We also explored the in vivo effect of PTEN inactivation on tumor cell growth and distant metastasis using nude mouse injection.</P> <P><B>Results</B></P> <P>PTEN knockout (KO) cells showed faster growth, migration and invasion than PTEN wild-type (WT) cells. When we injected the cells into nude mice, PTEN-KO cells showed faster growth and higher metastatic potential. In PTEN-KO cells, the levels of phosphorylated AKT (Ser-473 and Thr-308) were profoundly elevated and the expressions of phosphorylated GSK-3β (Ser9, inactive form) increased, while that of β-catenin decreased. Regarding the EMT markers, the expression of E-cadherin decreased but those of N-cadherin, vimentin and MMP-2 increased in the PTEN-KO cells. Especially, PTEN-KO cells showed the almost complete intra-nuclear shift of β-catenin and no β-catenin signal was observed in the cell membrane. Accordingly, PTEN-KO cells exhibited morphological changes such as loss of cell-to-cell contact, pseudopodia and the round shape, which are the typical phenotypes of EMT. Snail and Slug were also dominantly accumulated in the nucleus after PTEN inactivation.</P> <P><B>Conclusion</B></P> <P>All these data consistently support that PTEN inactivation contributes to EMT by nuclear translocation of β-catenin and Snail/Slug in lung cancer cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Epithelial-mesenchymal transition (EMT) is behind tumor invasion and metastasis. </LI> <LI> We examined the role of PTEN inactivation in EMT in lung cancer cells. </LI> <LI> Inactivated PTEN affects EMT by nuclear translocation of β-catenin and Snail/Slug. </LI> <LI> PI3K/AKT/GSK-3β pathway was essential for inducing EMT in PTEN inactivated cells. </LI> </UL> </P>