Synthesis and fluorescence study of water-soluble conjugated polymers for efficient FRET-based DNA detection

Nayak, R.R.,Nag, O.K.,Woo, H.Y.,Hwang, S.,Vak, D.,Korystov, D.,Jin, Y.,Suh, H. Elsevier 2009 CURRENT APPLIED PHYSICS Vol.9 No.3

Two cationic conjugated polyelectrolytes (CPs, P1i and P2i) were synthesized and examined as a fluorescence resonance energy transfer (FRET) donor to fluorescein (Fl)-labeled single-stranded DNA (ssDNA-Fl) using steady-state and time-resolved photoluminescence (PL) spectroscopy. The two polymers have the same π-conjugation with the main structural difference being the presence of the spiro-anthracenyl substituents orthogonal to the polymer backbone of P2i. These spiro-substituents can function as a molecular spacer that increases the intermolecular separation in the electrostatic complex with ssDNA-Fl. We measured almost complete PL quenching of the excited Fl* after electrostatic complexation with P1i (PL lifetime 4ns->78ps) and relatively moderate quenching with P2i (PL lifetime 4ns->552ps). A quenching efficiency (Φ<SUB>eT</SUB>) of 98% and 86% was obtained for P1i/ssDNA-Fl and for P2i/ssDNA-Fl, respectively. Both systems have same thermodynamic driving force for quenching as a result of them having the same electronic structures. This discrepancy can be explained in terms of the reduced quenching (via electron transfer, eT) by the increased D-A distance due to the existence of spiro-attached molecular spacers in P2i. It shows that thermodynamically favorable eT quenching can be controlled kinetically by modulating the D-A intermolecular distance using molecular spacers, which suggests an important molecular design guideline for efficient CPs-based DNA detection.

Computational and Experimental Study on Electronic Band Structure of Bismuth Ferrite: A Promising Visible Light Photocatalyst

G Thamizharasan,Eithiraj R,D,Enhbayar Enhtuwshin,So Jung Kim,Niroj Kumar Sahu,Arpan Kumar Nayak,HyukSu Han 한국세라믹학회 2020 세라미스트 Vol.23 No.4

Electronic band structure of bismuth ferrite (BFO) is studied by computational and experimental methods. Bandgap of BFO is precisely determined using optical absorption spectra as well as density functional calculation (DFT). Both methods give a comparable result that BFO can have both of direct or indirect (very close to direct) bandgap of about 2.0~2.2 eV. Furthermore, electronic transition in BFO occurs via the unoccupied O 2p to the occupied Fe 3d states or the d-d transition in Fe 3d states. Intriguing electronic structure of BFO, a narrow bandgap and a multiple electronic transition route, render it as a promising candidate for a visible light photocatalyst.

Additive Main Effects and Multiplicative Interaction Analysis of Host-Pathogen Relationship in Rice-Bacterial Blight Pathosystem

D. Nayak,L. K. Bose,S. Singh,P. Nayak 한국식물병리학회 2008 Plant Pathology Journal Vol.24 No.3

Host-pathogen interaction in rice bacterial blight pathosystem was analyzed for a better understanding of their relationship and recognition of stable pathogenicity among the populations of Xanthomonas oryzae pv. oryzae. A total number of 52 bacterial strains isolated from diseased leaf samples collected from 12 rice growing states and one Union Territory of India, were inoculated on 16 rice varieties, each possessing known genes for resistance. Analysis of variance revealed that the host genotypes (G) accounted for largest (78.4%) proportion of the total sum of squares (SS), followed by 16.5% due to the pathogen isolates (I) and 5.1% due to the I x G interactions. Application of the Additive Main effects and Multiplicative Interaction (AMMI) model revealed that the first two interaction principal component axes (IPCA) accounted for 66.8% and 21.5% of the interaction SS, respectively. The biplot generated using the isolate and genotypic scores of the first two IPCAs revealed groups of host genotypes and pathogen isolates falling into four sectors. A group of five isolates with high virulence, high absolute IPCA-1 scores, moderate IPCA-2 scores, low AMMI stability index ‘Di’ values and minimal deviations from additive main effects displayed in AMMI biplot as well as response plot, were identified as possessing stable pathogenicity across 16 host genotypes. The largest group of 27 isolates with low virulence, small IPCA-1 as well as IPCA- 2 scores, low Di values and minimal deviations from additive main effect predictions, possessed stable pathogenicity for low virulence. The AMMI analysis and biplot display facilitated in a better understanding of the host-pathogen interaction, adaptability of pathogen isolates to specific host genotypes, identification of isolates showing stable pathogenicity and most discriminating host genotypes, which could be useful in location specific breeding programs aiming at deployment of resistant host genotypes in bacterial blight disease control strategies.

Additive Main Effects and Multiplicative Interaction Analysis of Host-Pathogen Relationship in Rice-Bacterial Blight Pathosystem

Nayak, D.,Bose, L.K.,Singh, S.,Nayak, P. The Korean Society of Plant Pathology 2008 Plant Pathology Journal Vol.24 No.3

Host-pathogen interaction in rice bacterial blight pathosystem was analyzed for a better understanding of their relationship and recognition of stable pathogenicity among the populations of Xanthomonas oryzae pv. oryzae. A total number of 52 bacterial strains isolated from diseased leaf samples collected from 12 rice growing states and one Union Territory of India, were inoculated on 16 rice varieties, each possessing known genes for resistance. Analysis of variance revealed that the host genotypes(G) accounted for largest(78.4%) proportion of the total sum of squares(SS), followed by 16.5% due to the pathogen isolates(I) and 5.1% due to the $I{\times}G$ interactions. Application of the Additive Main effects and Multiplicative Interaction(AMMI) model revealed that the first two interaction principal component axes(IPCA) accounted for 66.8% and 21.5% of the interaction SS, respectively. The biplot generated using the isolate and genotypic scores of the first two IPCAs revealed groups of host genotypes and pathogen isolates falling into four sectors. A group of five isolates with high virulence, high absolute IPCA-1 scores, moderate IPCA-2 scores, low AMMI stability index '$D_i$' values and minimal deviations from additive main effects displayed in AMMI biplot as well as response plot, were identified as possessing stable pathogenicity across 16 host genotypes. The largest group of 27 isolates with low virulence, small IPCA-1 as well as IPCA-2 scores, low $D_i$ values and minimal deviations from additive main effect predictions, possessed stable pathogenicity for low virulence. The AMMI analysis and biplot display facilitated in a better understanding of the host-pathogen interaction, adaptability of pathogen isolates to specific host genotypes, identification of isolates showing stable pathogenicity and most discriminating host genotypes, which could be useful in location specific breeding programs aiming at deployment of resistant host genotypes in bacterial blight disease control strategies.

Gross motor dysfunction and balance impairments in children and adolescents with Down syndrome: a systematic review

Jain Preyal D.,Nayak Akshatha,Karnad Shreekanth D.,Doctor Kaiorisa N. 대한소아청소년과학회 2022 Clinical and Experimental Pediatrics (CEP) Vol.65 No.3

Background: Individuals with Down syndrome present with several impairments such as hypotonia, ligament laxity, decreased muscle strength, insufficient muscular cocontraction, inadequate postural control, and disturbed proprioception. These factors are responsible for the developmental challenges faced by children with Down syndrome. These individuals also present with balance dysfunctions.Purpose: This systematic review aims to describe the motor dysfunction and balance impairments in children and adolescents with Down syndrome.Methods: We searched the Scopus, ScienceDirect, MEDLINE, Wiley, and EBSCO databases for observational studies evaluating the motor abilities and balance performance in individuals with Down syndrome. The review was registered on PROSPERO.Results: A total of 1,096 articles were retrieved; after careful screening and scrutinizing against the inclusion and exclusion criteria, 10 articles were included in the review. Overall, the children and adolescents with Down syndrome showed delays and dysfunction in performing various activities such as sitting, pulling to stand, standing, and walking. They also presented with compensatory mechanisms to maintain their equilibrium in static and dynamic activities.Conclusion: The motor development of children with Down syndrome is significantly delayed due to structural differences in the brain. These individuals have inefficient compensatory strategies like increasing step width, increasing frequency of mediolateral center of pressure displacement, decreasing anteroposterior displacement, increasing trunk stiffness, and increasing posterior trunk displacement to maintain equilibrium. Down syndrome presents with interindividual variations; therefore, a thorough evaluation is required before a structured intervention is developed to improve motor and balance dysfunction.

Electrochemical Performance of a Layered-Spinel Integrated Li[Ni_1/3Mn_2/3]O₂ as a High Capacity Cathode Material for Li-Ion Batteries

Nayak, Prasant Kumar,Grinblat, Judith,Levi, Mikhael D.,Haik, Ortal,Levi, Elena,Talianker, Michael,Markovsky, Boris,Sun, Yang-Kook,Aurbach, Doron American Chemical Society 2015 Chemistry of materials Vol.27 No.7

<P>Li[Ni<SUB>1/3</SUB>Mn<SUB>2/3</SUB>]O<SUB>2</SUB> was synthesized by a self-combustion reaction (SCR), characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy, and studied as a cathode material for Li-ion batteries at 30 °C and 45 °C. The structural studies by XRD and TEM confirmed monoclinic Li[Li<SUB>1/3</SUB>Mn<SUB>2/3</SUB>]O<SUB>2</SUB> phase as the major component, and rhombohedral (LiNiO<SUB>2</SUB>), spinel (LiNi<SUB>0.5</SUB>Mn<SUB>1.5</SUB>O<SUB>4</SUB>), and rock salt Li<SUB>0.2</SUB>Mn<SUB>0.2</SUB>Ni<SUB>0.5</SUB>O as minor components. The content of the spinel phase increases upon cycling due to the layered-to-spinel phase transition occurring at high potentials. A high discharge capacity of about 220 mAh g<SUP>–1</SUP> is obtained at low rate (C/10) with good capacity retention upon cycling. However, LiNi<SUB>0.5</SUB>Mn<SUB>1.5</SUB>O<SUB>4</SUB> synthesized by SCR exhibits a discharge capacity of about 190 mAh g<SUP>–1</SUP> in the potential range of 2.4–4.9 V, which decreases to a value of 150 mAh g<SUP>–1</SUP> after 100 cycles. Because of the presence of the spinel component, Li[Ni<SUB>1/3</SUB>Mn<SUB>2/3</SUB>]O<SUB>2</SUB> cathode material exhibits part of its capacity at potentials around 4.7 V. Thus, it can be considered as an interesting high-capacity and high-voltage cathode material for high-energy-density Li-ion batteries. Also, the Li[Ni<SUB>1/3</SUB>Mn<SUB>2/3</SUB>]O<SUB>2</SUB> electrodes exhibit better electrochemical stability than spinel LiNi<SUB>0.5</SUB>Mn<SUB>1.5</SUB>O<SUB>4</SUB> electrodes when cycled at 45 °C.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2015/cmatex.2015.27.issue-7/acs.chemmater.5b00405/production/images/medium/cm-2015-00405w_0020.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm5b00405'>ACS Electronic Supporting Info</A></P>

Formation of metastable phases and nanocomposite structures in rapidly solidified Al–Fe alloys

Nayak, S.S.,Chang, H.J.,Kim, D.H.,Pabi, S.K.,Murty, B.S. Elsevier 2011 Materials science & engineering. properties, micro Vol.528 No.18

<P><B>Highlights</B></P><P>► Structures of nanocomposites in rapidly solidified Al–Fe alloys were investigated. ► Nanoquasicrystalline, amorphous and intermetallics phases coexist with α-Al. ► Nanoquasicrystalline phase was observed for the first time in the dilute Al alloys. ► Thermodynamic driving force plays dominant role in precipitation of Fe-rich phases. ► High hardness (3.57GPa) was observed for nanocomposite of Al–10Fe alloy.</P> <P><B>Abstract</B></P><P>In the present work the structure and morphology of the phases of nanocomposites formed in rapidly solidified Al–Fe alloys were investigated in details using analytical transmission electron microscopy and X-ray diffraction. Nanoquasicrystalline phases, amorphous phase and intermetallics like Al<SUB>5</SUB>Fe<SUB>2</SUB>, Al<SUB>13</SUB>F<SUB>4</SUB> coexisted with α-Al in nanocomposites of the melt spun alloys. It was seen that the Fe supersaturation in α-Al diminished with the increase in Fe content and wheel speed indicating the dominant role of the thermodynamic driving force in the precipitation of Fe-rich phases. Nanoquasicrystalline phases were observed for the first time in the dilute Al alloys like Al–2.5Fe and Al–5Fe as confirmed by high resolution TEM. High hardness (3.57GPa) was measured in nanocomposite of Al–10Fe alloy, which was attributed to synergistic effect of solid solution strengthening due to high solute content (9.17at.% Fe), dispersion strengthening by high volume fraction of nanoquasicrystalline phase; and Hall–Petch strengthening from finer cell size (20–30nm) of α-Al matrix.</P>

LABEL INCIDENCE ENERGY OF PARTIAL EDGE LABELED GRAPH

SABITHA D’SOUZA,GOWTHAM H. J.,SWATI NAYAK,PRADEEP G. BHAT 장전수학회 2021 Proceedings of the Jangjeon mathematical society Vol.24 No.1

Let G = (V,E) be a simple graph with vertex set V = fv1, v2, . . . , vng and edge set E = fe1, e2, . . . , emg. The label incidence matrix Bl(G) of G is the n m matrix whose (i, j)-entry is a if 0 la- beled edge incident to 0 labeled vertex, b if 1 labeled edge incident to 1 labeled vertex, c if unlabeled edge incident to 0 or 1 labeled vertex and 0 otherwise. The label incidence energy IEl(G) is the sum of the singular values of Bl(G). In this paper we give lower and upper bounds for IEl(G) in terms of graph parameters and we study label incidence energy of some families of graph.

HAMMING DISTANCE BETWEEN THE STRINGS GENERATED BY ADJACENCY MATRIX OF GENERALISED COMPLEMENTS OF A GRAPH AND THEIR SUM

SWATI NAYAK,SHANKAR UPADHYAY,SABITHA D’SOUZA,PRADEEP G. BHAT 장전수학회 2021 Advanced Studies in Contemporary Mathematics Vol.31 No.4

Let A(G) be the adjacency matrix of a graph G. Let s(v) denote the row entries of A(G) corresponding to the vertex v of G. The Hamming distance between the strings s(u) and s(v) is the number of positions in which s(u) and s(v) differ. In this paper, we study the Hamming distance between the strings generated by the adjacency matrix of generalised complements of a graph. We also compute sum of Hamming distances between all pairs of strings generated by the adjacency matrix of GPk and GP k(i).

NUMERICAL SOLUTION OF SOME BENCH-MARK FLOW PROBLEMS BY FINITE ELEMENT METHOD

Amlan Kusum Nayak,N. Venkatrayulu,D. Prithvi Raj 대한기계학회 1992 International Conference on Fluid Machinery Vol.1 No.1