A note on proof of Gordon's Conjecture

Kun Du 대한수학회 2018 대한수학회보 Vol.55 No.3

In this paper, we show a proof of Gordon's Conjecture by using Qiu's labels and two new labels.

Biomimetic Designing of Functional Silk Nanotopography Using Self-assembly

Kundu, Banani,Eltohamy, Mohamed,Yadavalli, Vamsi K.,Kundu, Subhas C.,Kim, Hae-Won American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.42

<P>In nature inorganic organic building units create multifunctional hierarchical architectures. Organic silk protein is particularly attractive in this respect because of its micro-nanoscale structural blocks that are attributed to sophisticated hierarchical assembly imparting flexibility and compressibility to designed biohybrid materials. In the present study, aqueous silk fibroin is assembled to form nano/microtopography on inorganic silica surface via a facile diffusion-limited aggregation process. This process is driven by electrostatic interaction and only possible at a specified aminated surface chemistry. The self-assembled topography depends on the age and concentration of protein solution as well as on the surface charge distribution of the template. The self-assembled silk trails closely resemble natural cypress leaf architecture, which is considered a structural analogue of neuronal cortex. This assembled surface significantly enhances anchorage of neuronal cell and cytoskeletal extensions, providing an effective nano/microtopographical cue for cellular recognition and guidance.</P>

Bioethanol production from deacetylated yellow poplar pretreated with oxalic acid recovered through electrodialysis

Kundu, Chandan,Jeong, So-Yeon,Lee, Jae-Won Elsevier 2016 Bioresource technology Vol.208 No.-

<P><B>Abstract</B></P> <P>Electrodialysis (ED) was used to develop a multistage oxalic acid recovery and pretreatment system to produce ethanol from deacetylated yellow poplar. Pretreatment of the biomass was performed at 150°C for 42min using 0.16M oxalic acid. The efficiency of oxalic acid recovery from the hydrolysate reached up to 92.32% in all the stages. Ethanol production and ethanol yield of ED-treated hydrolysate in each stage showed a uniform pattern ranging from 6.81g/L to 7.21g/L and 0.40g/g to 0.43g/g, respectively. The results showed that efficiency of ethanol production increased when deacetylated biomass and ED process was used. Ethanol yield from the pretreated biomass using simultaneous saccharification and fermentation (SSF) was in the range of 80.59–83.36% in all the stages. The structural characterization of the pretreated biomass at each stage was investigated and structural changes were not significantly different among the various pretreated biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Oxalic acid was effectively recovered by electrodialysis (ED). </LI> <LI> Reuse of oxalic acid recovered through ED was effective during multistage process. </LI> <LI> The properties of pretreated biomass on multistage process were stable and constant. </LI> <LI> Ethanol production on multistage process was stable and constant. </LI> <LI> Ethanol production increased when deacetylated biomass and ED process were used. </LI> </UL> </P>

Bioethanol production from detoxified hydrolysate and the characterization of oxalic acid pretreated Eucalyptus (Eucalyptus globulus) biomass

Kundu, C.,Lee, J.W. Elsevier 2016 INDUSTRIAL CROPS AND PRODUCTS Vol.83 No.-

<P>In this study, different detoxification treatments (XAD-4 resin adsorption [XAD] and electrodialysis) on oxalic acid pretreated hydrolysate were evaluated. Two different detoxification processes were applied to remove fermentation inhibitors from the oxalic acid pretreated hydrolysate of eucalyptus. The hydrolysates contain sugars (glucose, xylose, and arabinose) and inhibitors. Acetic acid was the main inhibitor in the original hydrolysate, and more total phenolic compounds were generated than hydroxymethyl furfural and furfural. The acetic acid was removed 100% by the electrodialysis process, and total phenolic compounds and furfural were effectively removed from the hydrolysate by XAD. Based on the process order, the combined electrodialysis-XAD process was more effective for ethanol fermentation compared to the combined XAD-electrodialysis process. Ethanol fermentation was successfully performed using the electrodialysis-XAD-treated hydrolysate and achieved a production of 7.83 g/L of ethanol, corresponding to an ethanol yield of 0.40 gig within 48 h. Fourier transform infrared, X-ray diffractometer, and scanning electron microscopy were used to investigate the characteristics of the raw material and pretreated biomass. The results showed that most of the hemicellulose was degraded during oxalic acid pretreatment. Therefore, the crystallinity value increased from 49.79% to 56.93%. The surface of the raw material was smooth, plump, and compact, whereas the pretreated biomass was more fragmented. (c) 2016 Elsevier B.V. All rights reserved.</P>

Template mediated protein self-assembly as a valuable tool in regenerative therapy

Kundu, B,Eltohamy, M,Yadavalli, VK,Reis, RL,Kim, HW Institute of Physics Publishing Ltd 2018 Biomedical Materials Vol.13 No.4

Evaluation of hepatoprotective activity of ethanol extract of Coccinia grandis (L.) Voigt. leaves on experimental rats by acute and chronic models

Kundu, Mintu,Mazumder, Rupa,Kushwaha, M.D. 경희한의학연구센터 2012 Oriental Pharmacy and Experimental Medicine Vol.12 No.2

Coccinia grandis Linn. (Cucurbitaceae) is a climbing perennial branched herb, distributed throughout India. Other plants under the same family have been reported for their hepatoprotective activity. The aim of this work was to study the hepatoprotective effect of crude ethanolic extract from the leaves of C. grandis against liver damage induced by Paracetamol and $CCl_4$ in rats. Administration of Paracetamol (750 mg/kg/day) and $CCl_4$ (3 ml/kg/day) showed a marked increase in SGOT, SGPT, ALP, bilirubin (total, direct), total proteins, globulin, cholesterol and decrease in albumin in comparison with the normal control group. The effect of ethanol extract of C. grandis at 150 mg/kg and 300 mg/kg doses reduced the serum activities caused by Paracetamol and $CCl_4$, which were observed to be statistically significant when compared with that of the control group. The activity exhibited/inhibited by the plant extract was found to be comparable to that of the standard hepatoprotective drug, Silymarin. Silymarin provided a better inhibition or exhibition of the biochemical parameters induced by paracetamol and carbon tetrachloride in rats. The activity may be due to the presence of either alkaloids or triterpenoids or reducing sugars or their combinations, as obtained from the preliminary phytochemical screening of the leaves of the plant. The extract showed no signs of acute toxicity up to a dose level of $3.2gkg^{-1}$ in rats by oral route. Thus, it could be concluded that ethanolic extract of C. grandis leaves possessed significant hepatoprotective activity.

Analytical tools for calculating the maximum heat transfer of annular stepped fins with internal heat generation and radiation effects

Kundu, Balaram,Lee, Kwan-Soo Elsevier 2014 ENERGY Vol.76 No.-

<P><B>Abstract</B></P> <P>ASFs (Annular stepped fins) require less material than ADFs (annular disc fins) while retaining the ability to produce the same cooling rate in a convection environment. A simple analysis was developed for ASFs that considered radiative heat transfer and heat generated by a nuclear reactor through linearization of the radiation terms. The linearized equations were solved by exact and approximate analytical methods. Without any linearization, a new closed-form analysis was established for the temperature profile with the help of the differential transform method. An integral differential transform method was introduced to determine the actual heat-transfer rate when heat was generated inside an ASF under nonlinear radiation surface conditions. The temperature results obtained using this analytical approach were compared with those obtained from a finite-difference analysis, and were in excellent agreement. The fin performance was defined as a function of the heat generated for a given set of design conditions. An optimization study with varying heat generation was carried out to compare the performance of ADFs and ASFs, which highlighted the superior aspects of an annular fin design.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new analytical model for ASF under heat generation and radiation heat transfer. </LI> <LI> Exact and approximate analysis for linearization of governing equation. </LI> <LI> A high accuracy obtained from approximate analysis. </LI> <LI> Fin heat transfer for nonlinear surface conditions and heat generation. </LI> <LI> Calculation of maximum heat transfer as a function of heat generation parameter. </LI> </UL> </P>

Nrf2-Keap1 Signaling as a Potential Target for Chemoprevention of Inflammation-Associated Carcinogenesis

Kundu, Joydeb Kumar,Surh, Young-Joon Springer-Verlag 2010 Pharmaceutical research Vol.27 No.6

Water Structure at the Lipid Multibilayer Surface: Anionic Versus Cationic Head Group Effects

Kundu, Achintya,Kwak, Kyungwon,Cho, Minhaeng American Chemical Society 2016 The Journal of physical chemistry B Vol.120 No.22

<P>Membrane water interface is a potential reaction site for many biochemical reactions. Therefore, a molecular level understanding of water structure and dynamics that strongly depend on the chemical structure of lipid is prerequisite for elucidating the role of water in biological reactions on membrane surface. Recently, we carried out femtosecond infrared pump probe studies of water structure and dynamics at multibilayer surfaces of zwitterionic phosphatidylcholine-analogue lipid (J. Phys. Chem. Lett. 2016, 7, 741). Here, to further elucidate the anionic and cationic headgroup effects on water, we study vibrational dynamics of water on lipid multibilayers formed by anionic phospho-glycerol lipid molecules as well as by cationic choline-derivatized lipid molecules. We observed two significantly different vibrational lifetime components (very fast 0.5 ps and slow 1.9 ps) of the OD stretch mode of HOD molecules at the negatively charged phospho-lipid multibilayer whereas only one vibrational lifetime component (1.6 ps) was observed at the positively charged choline-derivatized lipid multibilayer. From the detailed analyses about the vibrational energy and rotational relaxations of HOD molecules in lipid multibilayers composed of anionic lipid with phosphate and cationic lipid without phosphate, the role of phosphate group in structuring water molecules at phospholipid membrane interface is revealed.</P>

A cobalt(<small>II</small>) iminoiodane complex and its scandium adduct: mechanistic promiscuity in hydrogen atom abstraction reactions

Kundu, Subrata,Chernev, Petko,Engelmann, Xenia,Chung, Chan Siu,Dau, Holger,Bill, Eckhard,England, Jason,Nam, Wonwoo,Ray, Kallol The Royal Society of Chemistry 2016 Dalton Transactions Vol.45 No.37

<P>In addition to oxometal [Mn+=O] and imidometal [Mn+=NR] units, transient metal-iodosylarene [M(n- 2)+-O=IPh] and metal-iminoiodane [M(n- 2)+-N(R)=IPh] adducts are often invoked as a possible 'second oxidant' responsible for the oxo and imido group transfer reactivity. Although a few metal-iodosylarene adducts have been recently isolated and/or spectroscopically characterized, metal-iminoiodane adducts have remained elusive. Herein, we provide UV-Vis, EPR, NMR, XAS and DFT evidence supporting the formation of a metal-iminoiodane complex 2 and its scandium adduct 2-Sc. 2 and 2-Sc are reactive toward substrates in the hydrogen-atom and nitrene transfer reactions, which confirm their potential as active oxidants in metal-catalyzed oxidative transformations. Oxidation of para-substituted 2,6-di-tert-butylphenols by 2 and 2-Sc can occur by both coupled and uncoupled proton and electron transfer mechanisms; the exact mechanism depends on the nature of the para substituent.</P>