Synthesis, Structure, Magnetic Properties and Aqueous Optical Citrate Detection of Chiral Dinuclear Cu^II Complexes

Khatua, Snehadrinarayan,Kim, Kibong,Kang, Jina,Huh, Jung Oh,Hong, Chang Seop,Churchill, David G. WILEY-VCH Verlag 2009 European journal of inorganic chemistry Vol.2009 No.22

<P>Two chiral dimeric Cu<SUP>II</SUP> Schiff base complexes, Na<SUB>2</SUB>[Cu(S-lys)<SUB>2</SUB>·(H<SUB>2</SUB>O)<SUB>2</SUB>]·(ClO<SUB>4</SUB>)<SUB>2</SUB> (1) and [Cu(S-ornH)<SUB>2</SUB>·(H<SUB>2</SUB>O)<SUB>2</SUB>]·(ClO<SUB>4</SUB>)<SUB>2</SUB> (2) have been prepared by an easy one-pot method in which the L-lysine and L-ornithine-based Schiff base ligands are generated in situ. These complexes have been characterized by various spectroscopic techniques and single-crystal X-ray diffraction. The molecular structures show that both complexes are indeed dimeric with Cu<SUP>II</SUP> centers that are phenolate-bridged. Variable-temperature magnetic analysis revealed that a strong antiferromagnetic coupling interaction was mediated through the phenolate bridge between the two Cu<SUP>II</SUP> centers. Since these compounds were highly soluble in water, we explored carboxylate sensing capability through colorimetric indicator displacement assays (IDAs). By using pyrocatechol violet (PV) as a displaceable colorimetric indicator, citrate ion selectivity was demonstrated in 100 % water solution in the physiological pH range.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)</P> <B>Graphic Abstract</B> <P>Two chiral dimeric Cu<SUP>2+</SUP> complexes 1 and 2 have been prepared by a one pot method in which the L-lysine- and L-ornithine-based Schiff base ligands are generated in situ. Variable-temperature magnetic susceptibility measurements reveal strong antiferromagnetic coupling interactions. Selective citrate ion sensing was enabled through colorimetric indicator displacement assays in water at physiological pH. <img src='wiley_img/14341948-2009-2009-22-EJIC200900357-fig000.gif' alt='wiley_img/14341948-2009-2009-22-EJIC200900357-fig000'> </P>

Tuning of mechanical energy harvesting by intrinsic electrical conductivity in piezoceramics

Dipak Kumar Khatua(디팍 구말 카투아),Nirmal Prashanth Maria Joseph (니르말 프라샤츠 마리아 조세프라),Alluri Nagamlleswara Rao(올루리 나가마레스와라 라오),Gaurav Khandelwal(가우라프 칸델왈),Sang-Jae Kim(김상재) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.7

Preparation by Suspension Polymerization and Characterization of Polystyrene (PS)-Poly(methyl methacrylate) (PMMA) Core-Shell Nanocomposites

Dibyendu Debnath,B. B. Khatua 한국고분자학회 2011 Macromolecular Research Vol.19 No.6

The effect of nanoclay on the thermal stability of polystyrene (PS)-poly(methyl methacrylate) (PMMA)core-shell nanocomposites morphology prepared by in situ suspension polymerization technique was investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the formation of a PSPMMA core-shell structure, both in the absence and presence of the clay. Wide angle X-ray diffraction (WAXD)indicated the formation of a highly intercalated expanded clay morphology in the core-shell composite particles irrespective of the location of the clay in the nanocomposites. Thermo gravimetric analysis (TGA) indicated an improvement in the thermal stability of the core-shell nanocomposites compared to that of the neat PS-PMMA coreshell one. Differential scanning calorimetry (DSC) showed that the core-shell nanocomposite particles containing the clay had a higher glass transition (T_g) temperature than the neat PS-PMMA core-shell composites particles. On the other hand, the improvement in the thermal stability of the PS-PMMA core-shell composites was found to depend strongly on the location and loading of the clay in the core-shell nanocomposites. FTIR indicated a probable interaction between the carbonyl (>C=O) group of PMMA and hydroxyl (-OH) group of the clay.

Assessment of Roughness Coefficient for Meandering Compound Channels

Arpan Pradhan,Kishanjit Kumar Khatua 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.5

Factors affecting roughness coefficient in a meandering compound channel are investigated and used to predict Manning’sroughness by dimensional analysis. Factors affecting Manning’s roughness, are considered to be geometric as well as hydraulic,namely relative depth of flow, width ratio, bed slope and sinuosity for a meandering compound channel. An experimentalinvestigation was carried out for the highly meandering channel of sinuosity 4.11. Observations of various researchers, on thelaboratory study of meandering channels have also been used in the investigation. The proposed equation for predicting compositeManning’s roughness is used to estimate the conveyance of a channel with floodplain flow. The proposed dimensional analysismodel is observed to predict the conveyance capacity better than other existing methods of Manning’s n prediction.

Synthesis of Highly Exfoliated PS/Na+-MMT Nanocomposites by Suspension Polymerization Using Na+-MMT Clay Platelets as Suspension Stabilizer

Sunanda Sain,B. B. Khatua 한국고분자학회 2011 Macromolecular Research Vol.19 No.1

Synthesis of highly exfoliated polystyrene/Na^+-montmorillonite (PS/Na^+-MMT) nanocomposites using Na^+-MMT clay platelets as stabilizer during suspension polymerization of styrene monomer is discussed. Scanning electron microscopy (SEM) showed that the presence of a small amount of Na+-MMT during the suspension polymerization of styrene without any suspension stabilizer (PVA) resulted in the formation of spherical PS/Na^+-MMT nanocomposites beads with a wide distribution of sizes. The wide angle X-ray diffraction (WAXD) study revealed near delamination/high degree of swelling of Na^+-MMT clay platelets in water. The exfoliated clay platelets in water media prior to the polymerization of styrene monomer played the role of a stabilizer by preventing the agglomeration of the monomer droplets. Moreover, polymerization of the styrene monomer with organoclay (o-MMT) in the absence of a PVA stabilizer formed clusters of PS/o-MMT nanocomposites. WAXD and transmission electron microscopy (TEM) revealed a high level of delamination with minor intercalation of silicate layers in the PS/Na^+-MMT nanocomposites, whereas intercalated nanocomposites were produced from the styrene/o-MMT polymerization system. The thermal stability of PS was also increased significantly in the PS/Na+-MMT nanocomposite, compared to that of the PS/o-MMT nanocomposites.

Synthetic, Cyclic Voltammetric, Structural, EPR, and UV−Vis Spectroscopic Studies of Thienyl-Containing<i>meso</i>-A₂B-cor(Cr^V═O) Systems: Consideration of Three Interrelated Molecular Detection Modalities

Egorova, Olga A.,Tsay, Olga G.,Khatua, Snehadrinarayan,Meka, Bhupal,Maiti, Nilkamal,Kim, Min-Kyu,Kwon, Seong Jung,Huh, Jung Oh,Bucella, Daniela,Kang, Sa-Ouk,Kwak, Juhyoun,Churchill, David G. American Chemical Society 2010 Inorganic Chemistry Vol.49 No.2

An Efficient Compression Algorithm for Forthcoming New Species

Subhankar Roy,Sudip Mondal,Sunirmal Khatua,Moumita Biswas 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.11

Genomic repositories gradually increase individual and reference sequences, which shares long identical and near-identical strings of nucleotides. In this paper a lossless DNA data compression technique called Optimized Base Repeat Length DNA Compression (OBRLDNAComp) has been proposed, based upon redundancy of DNA sequences. For easy storage, retrieval time reducing and to find similarity within and between sequences compression is mandatory. OBRLDNAComp searches long identical and near-identical strings of nucleotides which are overlooked by other DNA specific compression algorithms. This technique is an optimal solution of longest possible exact repeat benefits towards compression ratio. It scans a sequence horizontally from left to right to find statistic of repeats then follow substitution technique to compress those repeats. The algorithm is straightforward and does not need any external reference file; it scans the individual file for compression and decompression. The achieved compression ratio 1.673 bpb outperforms many non-reference based compression methods.

Bio-waste onion skin as an innovative nature-driven piezoelectric material with high energy conversion efficiency

Maiti, Sandip,Kumar Karan, Sumanta,Lee, Juhyun,Kumar Mishra, Avnish,Bhusan Khatua, Bhanu,Kon Kim, Jin Elsevier 2017 Nano energy Vol.42 No.-

<P><B>Abstract</B></P> <P>Development of non-toxic, ultra-sensitive, and flexible bio-inspired piezoelectric nanogenerator has become a great challenge for next generation biomedical applications. High performance organic/inorganic materials based piezoelectric nanogenerators suffer from several unavoidable problems such as complex synthesis and high toxicity. Biodegradable and biocompatible piezoelectric material is utmost needed in in-vivo condition to harvest energy for biomedical applications. Here, we report a novel bio-piezoelectric nanogenerator (BPNG) using naturally abundant self-aligned cellulose fibrous untreated onion skin (OS) as efficient piezoelectric material having piezoelectric strength of ∼ 2.8 pC/N. The fabricated OSBPNG generated output voltage, current, instantaneous power density and high piezoelectric energy conversion efficiency of ≈ 18V, ≈ 166nA, ≈ 1.7μW/cm<SUP>2</SUP>, and ≈ 61.7%, respectively, and turn on 30 green LEDs by a single device under repeated compressive stress of ≈ 34kPa and ≈ 3.0Hz frequency. In addition, maximum output voltage (≈ 106V) was achieved when 6 units are connected in series, which instantaneously turns on 73 combined LEDs (30 green, 25 blue, and 18 red). OSBPNG is highly effective during throat movement such as coughing, drinking and swallowing. Furthermore, because it works at very low pressure originating from heart pulse or beat, it could be used in pacemakers and health care units. Finally, OSBPNG successfully differentiates speech signals, indicating its potential for speech recognition.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel homespun approach for bio-piezoelectric nanogenerator (OSBPNG) using onion skin. </LI> <LI> Plant materials are more useful than living creatures in both handling and supply. </LI> <LI> It works at low pressure even from heart pulse, that can be used in health care unit. </LI> <LI> OSBPNG shows output voltage of 18 V with high energy conversion efficiency (61.7%). </LI> <LI> Maximum output voltage (106 V) achieved by assembling 6 units, which turn on 73 LEDs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Naturally driven bio-waste and biocompatible onion skin base piezoelectric nanogenerator with high output performance (output voltage and area power density of ≈ 18V, and ≈ 1.7μW/cm<SUP>2</SUP>) and high energy conversion efficiency (≈ 61.7%) has been fabricated through simple homespun device fabrication method. More details on the materials and application can be found in the manuscript.</P> <P>[DISPLAY OMISSION]</P>

Cytokine profiles in intensive care unit delirium

Ryan J. Smith,Christian Lachner,Vijay P. Singh,Shubham Trivedi,Biswajit Khatua,Rodrigo Cartin-Ceba 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.3

Background: Neuroinflammation causing disruption of the blood-brain barrier and immune cell extravasation into the brain parenchyma may cause delirium; however, knowledge of the exact pathophysiologic mechanism remains incomplete. The purpose of our study was to determine whether cytokine profiles differ depending on whether delirium occurs in the setting of sepsis, coronavirus disease 2019 (COVID-19), or recent surgery.Methods: This prospective observational cohort study involved 119 critically ill patients admitted to a multidisciplinary intensive care unit (ICU) during 2019 and 2020. Delirium was identified using the validated confusion assessment method for the ICU. Multiple delirium risk factors were collected daily including clinical characteristics, hospital course, lab values, vital signs, surgical exposure, drug exposure, and COVID-19 characteristics. Serums samples were collected within 12 hours of ICU admission and cytokine levels were measured.Results: The following proinflammatory cytokines were elevated in our delirium population: tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-18, C-C motif ligand (CCL) 2, CCL3, C-X-C motif chemokine ligand (CXCL)1, CXCL10, IL-8, IL-1 receptor antagonist, and IL-10. Analysis of relative cytokine levels in those patients that developed delirium in the setting of sepsis, COVID-19, and recent surgery showed elevations of CCL2, CXCL10, and TNF-α in both the sepsis and COVID-19 group in comparison to the postsurgical population. In the postsurgical group, granulocyte colony-stimulating factor was elevated and CXCL10 was decreased relative to the opposing groups.Conclusions: We identify several cytokines and precipitating factors known to be associated with delirium. However, our study suggests that the cytokine profile associated with delirium is variable and contingent upon delirium precipitating factors.

Nanostructured Metal/Carbon Hybrids for Electrocatalysis by Direct Carbonization of Inverse Micelle Multilayers

Jang, Yu Jin,Jang, Yoon Hee,Han, Sang-Beom,Khatua, Dibyendu,Hess, Claudia,Ahn, Hyungju,Ryu, Du Yeol,Shin, Kwanwoo,Park, Kyung-Won,Steinhart, Martin,Kim, Dong Ha American Chemical Society 2013 ACS NANO Vol.7 No.2

<P>A synthetic strategy for the fabrication of graphitic carbon nanomaterials containing highly dispersed arrays of metal nanoparticles is reported. This synthetic strategy involves successive deposition of inverse micelle monolayers containing a metal precursor and reduction of the latter, followed by direct carbonization of the obtained multilayer structure of inverse micelles containing metal nanoparticles. Thus, a “direct-carbonization” concept, in which the block copolymer simultaneously serves as soft template and as carbon source, was combined with a multilayer buildup protocol. The inner architecture of the multilayer structures consisting of carbon and metal nanoparticles was studied by X-ray reflectivity, grazing incidence small-angle X-ray scattering, and cross-sectional transmission electron microscopy imaging. The hexagonal near ordering of the metal nanoparticles in the block copolymer micelle multilayers was by and large conserved after carbonization. The resulting carbon structures containing multilayers of highly dispersed metal nanoparticles exhibit superior electrocatalytic activity in formic acid and methanol oxidation, suggesting that they are promising electrode materials for fuel cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-2/nn3056115/production/images/medium/nn-2012-056115_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn3056115'>ACS Electronic Supporting Info</A></P>