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Ramasamy, Mohankandhasamy,Lee, Jintae Hindawi Publishing Corporation 2016 BioMed research international Vol.2016 No.-
<P>Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. There is an urgent need for novel antimicrobial or antibiofilm surfaces and biomedical devices that provide protection against biofilm formation and planktonic pathogens, including antibiotic resistant strains. In this context, recent developments in the material science and engineering fields and steady progress in the nanotechnology field have created opportunities to design new biomaterials and surfaces with anti-infective, antifouling, bactericidal, and antibiofilm properties. Here we review a number of the recently developed nanotechnology-based biomaterials and explain underlying strategies used to make antibiofilm surfaces. </P>
Soluble conducting polymer-functionalized graphene oxide for air-operable actuator fabrication
Ramasamy, M.,Mahapatra, S.,Yoo, H.,Kim, Y.,Cho, J. Royal Society of Chemistry 2014 Journal of Materials Chemistry A Vol.2 No.13
An effective route for the preparation of a processable, conducting polymer-functionalized graphene oxide for actuator applications is investigated. First, graphene oxide (GO) is covalently functionalized with a 3-thiophene acetic acid (TAA) monomer by an esterification reaction. Then, the TAA-functionalized GO is self-polymerized by chemical oxidative polymerization to yield poly(3-thiophene acetic acid)functionalized GO (GO-f-PTAA). Further, the GO-f-TAA is also copolymerized with thiophene (Th) to yield GO-f-PTAA-co-PTh. The synthesis of GO-f-PTAA and GO-f-PTAA-co-PTh composites is confirmed by Fourier transform infrared, H-1-nuclear magnetic resonance, and X-ray photoelectron spectroscopies. The composites show better electrochemical properties than pure PTAA and superior solubility in organic solvents compared to pure GO. Using the soluble GO-f-PTAA and GO-f-PTAA-co-PTh composites, air-operable actuators are fabricated and their actuation performance is investigated. The copolymer-functionalized GO actuator exhibits good electroactive actuation behavior between 2 and 4 V, mainly because of the enhanced electrochemical performance of the composites, whereas the pure PTAA and GO-f-PTAA actuators do not show actuation under the applied voltage. The soluble conducting polymer-functionalized graphene composites developed in this study have potential applications in the fabrication of actuators that can be operated in air.
Finite-time boundedness and extended passive analysis for fuzzy Markov jump systems with saturation
Ramasamy Kavikumar,Ramalingam Sakthivel,Oh-Min Kwon 제어로봇시스템학회 2022 제어로봇시스템학회 국제학술대회 논문집 Vol.2022 No.11
In this work, the problem of extended passive-based finite-time control is studied for Takagi–Sugeno fuzzy Markov jump systems with actuator saturation over a finite horizon. The focus is on the design of a mode-dependent nonfragile controller such that the resulting closed-loop system is stochastically finite-time bounded and extended passively. Specifically, by using the mode-dependent Lyapunov-Krasovskii functional technique and Abel lemma-based finite sum inequality, a sufficient condition is established to ensure the finite-time bounded of the addressed systems. Finally, the feasibility and effectiveness of the proposed design are verified and demonstrated by a simulation example.
Ramasamy, Mohankandhasamy,Lee, Jin-Hyung,Lee, Jintae Elsevier 2017 Colloids and surfaces. B, Biointerfaces Vol.160 No.-
<P><B>Abstract</B></P> <P>The objective of the present study was to develop a one-pot strategy to synthesis gold nanoparticle complexes using cinnamaldehyde, a potent antibiofilm agent which in its free form, exhibits high volatility and unstable nature. Hence, we developed cinnamaldehyde gold nanoparticles (CGNPs) in a single step to overcome the limitations of free cinnamaldehyde. Furthermore, reduction abilities of cinnamaldehyde under different experimental conditions, that is, varying precursor concentrations of cinnamaldehyde and gold, metal salts, pH, temperature, and light sources, were investigated. UV–vis spectroscopy, transmission electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and dynamic light-scattering measurements revealed that heat influenced the nanoparticle formation in the presence of cinnamaldehyde, and as produced cinnamaldehyde immobilized on gold nanoparticles were spherical, monodispersed, and stable by surface charge. CGNPs containing 0.01% cinnamaldehyde by weight exhibited effective biofilm inhibition of up to >80% against Gram positive bacteria (methicillin-sensitive and -resistant strains of <I>Staphylococcus aureus,</I> MSSA and MRSA, respectively) and Gram negative (<I>Escherichia coli</I> and <I>Pseudomonas aeruginosa</I>) and a fungus <I>Candida albicans</I>. In addition, CGNPs attenuated the virulence of <I>C. albicans</I> by inhibiting hyphae formation. Based on observations of their antibiofilm effects and confocal microscopy findings, CGNPs caused biofilm damage by direct contact. Thus, cinnamaldehyde appears to be a promising reduction material for the eco-friendly, one-pot synthesis of CGNPs with excellent antibiofilm activity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> One-pot, cinnamaldehyde gold nanoparticle complexes (CGNPs) were produced. </LI> <LI> Heat plays predominant role in metal salt reduction with cinnamaldehyde. </LI> <LI> CGNPs exhibited antibiofilm activity against pathogens including fungi. </LI> <LI> Cinnamaldehyde is a potent reductant for nanoparticle synthesis. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Ramasamy Selvam,Marimuthu Saravanakumar,Subramaniyam Suresh,CV Chandrasekeran,D Souza Prashanth 아세아·태평양축산학회 2018 Animal Bioscience Vol.31 No.11
Objective: The study was designed to establish choline deficiency model (CDM) in broilers for evaluating efficacy of polyherbal formulation (PHF) in comparison with synthetic choline chloride (SCC). Methods: A total of 2,550 one-day-old Cobb 430 broiler chicks were randomly assigned to different groups in three experiments. In experiment 1, G1 and G2 served as normal controls and were fed a basal diet with 100% soybean meal (SBM) as a major protein source supplemented with and without SCC, respectively. In G3, G4, G5, and G6 groups, SBM was replaced at 25%, 50%, 75%, and 100% by soy protein isolate (SPI) to induce a graded level of choline deficiency. In experiment 2, PHF (500 and 1,000 g/ton) in comparison with SCC (1,000 g/ton) were evaluated. In experiment 3, dose-response of PHF (200, 400, and 500 g/ton) with SCC (400 g/ton) was determined. Results: Replacement of SBM by SPI produced a linear decrease in body weight gain (BWG) with a poor feed conversion ratio (FCR). 25% SBM replacement by SPI yielded an optimum negative impact on BWG and FCR; hence, it is considered for further studies. In experiment 2, PHF (500 and 1,000 g/ton) and SCC (1,000 g/ton) showed a similar performance in BWG, FCR and relative liver weight. In experiment 3, PHF produced an optimum efficacy at 400 g/ton and was comparable to SCC in the restoration of serum aspartate aminotransferase activity, abdominal fat, breast muscle lipid content and liver histopathological abnormalities. Conclusion: Replacement of SBM by SPI caused choline deficiency characterised by worsening of BWG, FCR, elevation in liver enzymes and histopathological changes indicating fatty liver. CDM was found valid for evaluating SCC and PHF. It is concluded that PHF has the potential to mimic biological activities of SCC through the restoration of negative effects caused by CDM.
Ramasamy, Mohankandhasamy,Yi, Dong Kee,An, Seong Soo A Dove Medical Press 2015 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.10 No.specal
<P><I>Escherichia coli</I> O157:H7 (O157) is a Gram negative and highly virulent bacteria found in food and water sources, and is a leading cause of chronic diseases worldwide. Diagnosis and prevention from the infection require simple and rapid analysis methods for the detection of pathogens, including O157. Endogenous membrane peroxidase, an enzyme present on the surface of O157, was used for the colorimetric detection of bacteria by catalytic oxidation of the peroxidase substrate. In this study, we have analyzed the impact of the synthesized bare gold nanorods (AuNRs) and silica-coated AuNRs on the growth of <I>E. coli</I> O157. Along with the membrane peroxidase activity of O157, other bacteria strains were analyzed. Different concentrations of nanorods were used to analyze the growth responses, enzymatic changes, and morphological alterations of bacteria by measuring optical density, 3,3′,5,5′-tetramethylbenzidine assay, flow cytometry analysis, and microscopy studies. The results revealed that O157 showed higher and continuous membrane peroxidase activity than other bacteria. Furthermore, O157 treated with bare AuNRs showed a decreased growth rate in comparison with the bacteria with surface modified AuNRs. Interestingly, silica-coated AuNRs favored the growth of bacteria and also increased membrane peroxidase activity. This result can be particularly important for the enzymatic analysis of surface treated AuNRs in various microbiological applicants.</P>