Medical student’s perception to different types of set induction in anatomy lectures

Suresh Narayanan,Suresh Narayanan,Nachiket Shankar,Vimala Ananthy 대한해부학회 2019 Anatomy & Cell Biology Vol.52 No.3

Set induction refers to the process of using a thought-provoking statement, interesting fact, or an audio-visual stimulus at the beginning of lecture to gain student’s attention and give an overview about the lecture topic. In the present study, students were introduced to three types of set induction namely narratives, food-based analogies and humor-based images or activities at the beginning of anatomy lecture and their response to it is collected and analyzed. The objective of the study is to estimate the difference in a questionnaire-based perception score between the three different types of set induction; estimate sex differences in the questionnaire-based perception score. Students rated the validated, 7-item perception questionnaire using a 5-point Likert scale. Students felt that food-based analogies and humor-based images were more interesting, motivated them to participate in lecture-discussion than the narrative set induction. The familiarity of set induction varied between all the three different types of set induction. There was no significant difference in the perception of different types of set induction between male and female undergraduate students. Based on the student’s feedback, it could also serve as a memory aid and ease the students learning experience. Majority of students responded positively to the use of set induction and recommended for its use in future classes.

Update on Myanmar’s Ethnic Peace Process : Surge in Violence in Rakhine State and Impasse over Charter Amendments

( Narayanan Ganesan ) 서울대학교 통일평화연구원 2019 통일과 평화 Vol.11 No.1

There were a number of new developments in Myanmar’s ethnic peace process since the last Panglong Peace Conference in July 2018. The first of these was a unilateral ceasefire declaration by the military for its north, northeast and southern commands for a period of 4 months from January to April 2019. According to the military this announcement was meant to facilitate the peace process in order to try and end armed conflict in the country by 2020 and in time for the next election. However, this announcement had little impact on Rakhine state in the west where attempts by the Arakan Army (AA) to establish a foothold in the state has led to a serious surge in fighting as well as new groups of internally displaced persons. This new front has now become the most volatile region in the country and adds on to a list of grievances between Rakhine nationalists in the state on the one hand and the central government and the military on the other. Another major development has been attempts by the National League for Democracy (NLD)-led parliament to amend the constitution, much to the chagrin of the military that has stoutly opposed it thus far. This article examines the most important developments that have occurred in Myanmar’s ethnic peace process since the Third 21st Century Panglong Peace Conference that was held in August 2018. Specifically it examines the military’s unilateral ceasefire that was declared in January 2019, and the upsurge of violence in Rakhine state since then. Then it goes on to look at the Karen National Union’s withdrawal from formal meetings of the peace process since last October and the chances of the Karenni National Progressive Party (KNPP) possibly signing on to the Nationwide Ceasefire Agreement (NCA) in the footsteps of the New Mon State Party (NMSP) and the Lahu Democratic Union (LDU). The fourth section outlines the continued fighting in the Shan states between the Ta’ang National Liberation Army (TNLA) on the one hand and the Restoration Council of the Shan States (RCSS) and the Shan State Progress Party (SSPP) on the other that has continued unabated with a seeming dynamic of its own. The fifth section looks at continued Chinese attempts to broker peace between the Northern Alliance and the government while the final section examines the dynamics associated with the NLD-led parliament’s attempts to amend the 2008 Constitution that has put it on a seeming collision course with the military. The concluding section then describes the likely future issues and trajectories in the peace process.

Preparation and characteristics of nano-grained calcium phosphate coatings on titanium from ultrasonated bath at acidic pH

Narayanan, R.,Kwon, Tae-Yub,Kim, Kyo-Han Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of biomedical materials research. Part B, Vol.b85 No.1

<P>Electrochemically deposited nano-grained calcium phosphate coatings were produced on titanium substrates using aqueous electrolyte at acidic pH. Different coatings were produced by using cathodic current densities ranging from 10 to 50 mA/cm<SUP>2</SUP> from an ultrasonated electrolytic bath. These coatings contained dicalcium phosphate dihydrate as the predominant phase and hydroxyapatite as the minor phase. With increasing current density, hydroxyapatite content in the coatings increased. Dicalcium phosphate grains had size in the range of 55–85 nm and hydroxyapatite had grains in the size range of 20–25 nm. Scanning electron microscopy showed that the morphology of the coatings obtained at lower current densities had acicular structure. With increasing current densities, the needles became blunt and small and finally, at 50 mA/cm<SUP>2</SUP> the coating had globular deposits. Surface roughness of the coatings also increased with increasing deposition current density. Tensile bond strengths of the coatings were in the range of 3.6–6.9 MPa and decreased with increase of deposition current density. Heat-treatment of the coatings for 2 h at 500°C completely eliminated the dicalcium phosphate phase and resulted in mono hydroxyapatite phase containing grains in the size range of 20–30 nm. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008</P>

Unnatural amino acid-mediated synthesis of silver nanoparticles and their antifungal activity against Candida species

Narayanan, Kannan Badri,Park, Hyun Ho Springer-Verlag 2014 JOURNAL OF NANOPARTICLE RESEARCH Vol.16 No.8

Highly selective and quantitative colorimetric detection of mercury(II) ions by carrageenan-functionalized Ag/AgCl nanoparticles

Narayanan, K.B.,Han, S.S. Applied Science Publishers ; Elsevier Science Ltd 2017 Carbohydrate polymers Vol.160 No.-

The natural algal polysaccharide carrageenan was used for the greener synthesis of silver/silver chloride nanoparticles (Carr-Ag/AgCl NPs) without any toxic chemicals. We report the robust, highly selective, and sensitive colorimetric sensing of Hg<SUP>2+</SUP> ions using Carr-Ag/AgCl NPs without any further surface modification. The dark-brown color of a solution of Carr-Ag/AgCl NPs turned to white in a concentration-dependent manner with the addition of Hg<SUP>2+</SUP> ions, confirming the interaction of Carr-Ag/AgCl NPs with Hg<SUP>2+</SUP> ions. The plot of the extinction ratio of absorbance at 350nm to 450nm (A<SUB>350</SUB>/A<SUB>450</SUB>) for Carr-Ag/AgCl NPs against the concentration of [Hg<SUP>2+</SUP>] ions was linear, and the calibration curve was A<SUB>350</SUB>/A<SUB>450</SUB>=1.05254+0.00318xC<SUB>Hg</SUB> with a lower detection limit of 1μM. This portable and cost-effective method for mercury(II) ion sensing is widely applicable in on-field qualitative and quantitative measurements of [Hg<SUP>2+</SUP>] ions in environmental or biological samples.

Fretting corrosion of lubricated tin-plated contacts

Narayanan, T.S.N. Sankara,Park, Young Woo,Lee, Kang Yong Emerald Group Publishing Limited 2008 Industrial lubrication and tribology Vol.60 No.5

<B>Purpose</B> - The objective of this paper is to study the effect of a commercial lubricant, which contains a 50-50 mixture of zinc diamyldithiocarbamate and petroleum oil, on the fretting corrosion of tin-plated copper alloy contacts. <B>Design/methodology/approach</B> - The change in contact resistance as a function of fretting cycles was used to assess the effectiveness of the lubricant in preventing the fretting corrosion of tin-plated contacts. The surface profile, surface roughness, extent of fretting damage and extent of oxidation of the contact zone were assessed by a laser scanning microscope and surface analytical techniques to correlate the change in contact resistance with fretting cycles. <B>Findings</B> - The lubricant film provides a surface coverage of 6.76±1?mg/cm<SUP>2</SUP> and it easily establishes metallic asperity contact between the mated tin-plated contacts. The contact resistance of lubricated contacts remains stable for several thousand fretting cycles. Lubricated contacts reach a threshold value of 0.1?O around 100,000 cycles, whereas unlubricated contact reaches this value around 13,500 cycles itself. For lubricated contacts, the extent of mechanical wear of the tin coating is significantly reduced. As a result, they experience a lesser damage at the contact zone and exhibit a smoother profile. The formation of tin oxide is not appreciable and there is no oxide accumulation at the contact zone even at 380,000 cycles. The lubricant is very effective in delaying the fretting wear during the initial stages and in preventing the oxidation and accumulation of oxidation products at the contact zone in the later stages. <B>Originality/value</B> - Metallic dialkyldithiocarbamates are useful anti-wear and extreme pressure additives for lubricating oils. Dithiocarbamates improve the antioxidant properties of the lubricants and are effective in reducing the wear and increasing the friction-reducing and load-carrying ability of the base stock. The use of molybdenum dithiocarbamate as a grease additive is found to be effective in reducing fretting corrosion of ball bearings under random rotary vibrating conditions. The effect of dithiocarbamate containing lubricant oils or greases on the fretting corrosion of electrical contacts has not far been studied. The paper explores the effect of a lubricant that contains a 50-50 mixture of petroleum oil and zinc diamyldithiocarbamate on the fretting corrosion of tin-plated contact.

Dual-crosslinked poly(vinyl alcohol)/sodium alginate/silver nanocomposite beads – A promising antimicrobial material

Narayanan, Kannan Badri,Han, Sung Soo Elsevier 2017 Food chemistry Vol.234 No.-

<P><B>Abstract</B></P> <P>In this paper, we report the immobilization of borate-stabilized silver nanoparticles (AgNPs) as nanofillers in dual-crosslinked polymers comprised of poly(vinyl alcohol) (PVA) and sodium alginate (SA) at different ratios. Ionic-crosslinking using Ca<SUP>2+</SUP> ions and physical-crosslinking by freeze-thawing were used to entrap silver nanoparticles in the prepared PVA/SA/AgNPs nanocomposite beads. These polymeric nanocomposites were characterized by UV–Vis, XRD, FE–SEM, FT-IR, TGA, and using rheological and swelling properties. The antibacterial activities of these PVA/SA/AgNPs nanocomposites were evaluated against <I>Escherichia coli</I> O157: H7, which causes escherichiosis through contaminated food and water. The results obtained indicated that PVA/SA/AgNPs nanocomposite formed with a ratio 10/90 of PVA to SA (formulation F5) exhibited high bactericidal activity, with entrapment of AgNPs and had excellent rheological and thermal stabilities. Due to the low cost and effectiveness of these antimicrobial nanocomposites, they have potential as an active food-packaging material for food safety and to extend shelf-life of packaged foods.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Antimicrobial polymeric/metal nanocomposites can be used in active food packaging. </LI> <LI> PVA and SA at different ratios were used to prepare various PVA/SA/AgNPs composites. </LI> <LI> Dual-crosslinking of polymer/silver nanocomposites entraps silver nanoparticles. </LI> <LI> <I>Escherichia coli</I> (∼10<SUP>11</SUP> CFU/ml) were killed by PVA/SA/AgNPs beads in batch culture. </LI> <LI> Effective killing of <I>E. coli</I> (∼10<SUP>8</SUP> CFU/ml) cells in contact with PVA/SA/AgNPs surface. </LI> </UL> </P>

Polychlorinated Biphenyls (PCBs) in the Bio-geochemistry of Oceans

Narayanan Kannan 한국해양바이오학회 2007 한국해양바이오학회지 Vol.2 No.4

Optimal Placement of Distributed Generators in Radial Distribution System for Reducing the Effect of Islanding

Narayanan. K,Shahbaz A. Siddiqui,Manoj Fozdar 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

The present trend of increasing the penetration levels of Distributed Generator (DG) in the distribution network has made the issue of Islanding crucial for the reliable operation of the network. The islanding, if not detected early may lead to the collapse of the system as it can drive the distribution system to the cascaded failure. In this paper, an extensive study of the effect of DG placement and sizing is performed by dividing the system into different zones to obtain a reduced effect of islanding. The siting and sizing of DG is carried out to improve the overall voltage profile or/and reduction in active power loss using two stage Genetic Algorithm (GA). In the first stage a basic knockout selection is considered and the best population is taken for next stage, where roulette selection for crossover and mutation is performed for optimal placement and sizing of DGs. The effect of the islanding, due to load variations is reduced by optimal siting and sizing of DG. The effectiveness of the proposed scheme is tested on the IEEE 33 and 69 radial bus systems and the results obtained are promising.

Toll/interleukin-1 receptor (TIR) domain-mediated cellular signaling pathways.

Narayanan, Kannan Badri,Park, Hyun Ho Rapid Science Publishers ; Kluwer Academic Publish 2015 Apoptosis Vol.20 No.2

<P>Innate immunity, which is the first line of host defense against invading microbial pathogens in multicellular organisms, occurs through germline-encoded pattern-recognition receptors. The Toll-like receptor/Interleukin (IL)-1 receptor (TLR/IL-1R) superfamily comprises proteins that contain the phylogenetically conserved Toll/IL-1 receptor (TIR) domain, which is responsible for the propagation of downstream signaling through recruitment of TIR domain containing cytosolic adaptor proteins such as MyD88, TIRAP/MAL, TRIF, TRAM and SARM. These interactions activate transcription factors that regulate the expression of various proinflammatory cytokines (IL-1, IL-6, IL-8 and TNF-관) and chemokines. Activation of the TLR/IL-1R signaling pathway promotes the onset of inflammatory diseases, autoimmune diseases and cancer; therefore, this pathway can be used for the development of therapeutic strategies against these types of pathogenesis. In this review paper, we illustrate the role of the TIR-TIR domain interaction with the TLR/IL-1R signaling pathway in inflammation and apoptosis and recent therapeutic drugs targeted to inhibit the downstream signaling cascade for treatment of inflammatory diseases and cancer.</P>