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Sadashiv,Anupama Modi,Manoj Khokhar,Praveen Sharma,Rajnish Joshi,Sudhanshu Shekhar Mishra,Rajay N Bharshankar,Sunita Tiwari,Pankaj Kumar Singh,Vivek Vidyadhar Bhosale,Mahendra Pal Singh Negi 대한비만학회 2021 The Korean journal of obesity Vol.30 No.3
Background: It is well established that obesity is a major health risk in diabetes and associated diseases. Epigenetic changes, specially DNA methylation, play an important role in regulation of adipokines. The objective of the present study was to evaluate the DNA methylation status at the promoter region of the leptin gene in obese individuals and its association with metabolic risk factors. Methods: The study included obese (n=100) and non-obese (n=75) individuals aged 25–45 years, and measured their physical, biochemical parameters (glucose, insulin, and lipid profiles) and leptin, DNA methyltransferase 1 (DNMT1), and DNA methyltransferase 3 beta (DNMT3b) mRNA expressions with real-time reverse transcription-polymerase chain reaction (qRT-PCR). DNA methylation of the leptin gene at the promoter region was analyzed by methyl-specific qPCR . Results: The study found that the DNA methylation level at the promoter area of the leptin gene was negatively associated with weight in obese subjects. Furthermore, study findings showed that the DNA methylation level was negatively associated with fasting insulin, glucose, homeostatic model assessment for insulin resistance, and total cholesterol. There was also a higher expression of DNMT1 and DNMT-3b in obese subjects as compared with non-obese subjects. Conclusion: The leptin epigenetic profile may be associated with obesity and its associated metabolic risk factors.
Tiwari, N.,Singh, S.B.,Ram, M. The Korean Reliability Society 2010 International Journal of Reliability and Applicati Vol.11 No.2
This paper deals with the reliability analysis of a complex system, which consists of two subsystems A and B connected in series. Subsystem A has only one unit and B has two units $B_1$ and $B_2$. Marked process has been applied to model the complex system. Present reliability model incorporated two repairmen: supervisor and novice to repair the failed units. Supervisor is always there and the novice remains in vacation and is called for repair as per demand. The repair rates for supervisor and novice follow general and exponential distributions respectively and the failure time for both the subsystems follows exponential distribution. The model is analyzed under "Head of line repair discipline". By employing supplementary variable technique, Laplace transformation and Gumbel-Hougaard family of copula various transition state probabilities, reliability, availability and cost analysis have been obtained along with the steady state behaviour of the system. At the end some special cases of the system have been taken.
Accelerated Bone Regeneration by Two-Photon Photoactivated Carbon Nitride Nanosheets
Tiwari, Jitendra N.,Seo, Young-Kyo,Yoon, Taeseung,Lee, Wang Geun,Cho, Woo Jong,Yousuf, Muhammad,Harzandi, Ahmad M.,Kang, Du-Seok,Kim, Kwang-Youn,Suh, Pann-Ghill,Kim, Kwang S. American Chemical Society 2017 ACS NANO Vol.11 No.1
<P>Human bone marrow-derived mesenchymal stem cells (hBMSCs) present promising opportunities for therapeutic medicine. Carbon derivatives showed only marginal enhancement in stem cell differentiation toward bone formation. Here we report that red-light absorbing carbon nitride (C3N4) sheets lead to remarkable proliferation and osteogenic differentiation by runt-related transcription factor 2 (Runx2) activation, a key transcription factor associated with osteoblast differentiation. Accordingly, highly effective hBMSCs-driven mice bone regeneration under red light is achieved (91% recovery after 4 weeks compared to 36% recovery in the standard control group in phosphate-buffered saline without red light). This fast bone regeneration is attributed to the deep penetration strength of red light into cellular membranes via tissue and the resulting efficient cell stimulation by enhanced photocurrent upon two-photon excitation of C3N4 sheets near cells. Given that the photoinduced charge transfer can increase cytosolic Ca2+ accumulation, this increase would promote nucleotide synthesis and cellular proliferation/differentiation. The cell stimulation enhances hBMSC differentiation toward bone formation, demonstrating the therapeutic potential of near-infrared two-photon absorption of C3N4 sheets in bone regeneration and fracture healing.</P>
Tiwari, Jitendra N.,Kemp, Kingsley Christian,Nath, Krishna,Tiwari, Rajanish N.,Nam, Hong-Gil,Kim, Kwang S. American Chemical Society 2013 ACS NANO Vol.7 No.10
<P>Controlling the morphology and size of platinum nanodendrites (PtDs) is a key factor in improving their catalytic activity and stability. Here, we report the synthesis of PtDs on genomic-double-stranded-DNA/reduced-graphene-oxide (gdsDNA/rGO) by the NaBH<SUB>4</SUB> reduction of H<SUB>2</SUB>PtCl<SUB>6</SUB> in the presence of plant gdsDNA. Compared to industrially adopted catalysts (<I>i.e.</I>, state-of-the-art Pt/C catalyst, Pt/rGO, Pt<SUB>3</SUB>Co, <I>etc.</I>), the as-synthesized PtDs/gdsDNA/rGO hybrid displays very high oxygen reduction reaction (ORR) catalytic activities (much higher than the 2015 U.S. Department of Energy (DOE) target values), which are the rate-determining steps in electrochemical energy devices, in terms of onset-potential, half-wave potential, specific-activity, mass-activity, stability, and durability. Moreover, the hybrid exhibits a highly stable mass activity for the ORR over a wide pH range of 1–13. These exceptional properties would make the hybrid applicable in next-generation electrochemical energy devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-10/nn4038404/production/images/medium/nn-2013-038404_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn4038404'>ACS Electronic Supporting Info</A></P>
Engineered Carbon-Nanomaterial-Based Electrochemical Sensors for Biomolecules
Tiwari, Jitendra N.,Vij, Varun,Kemp, K. Christian,Kim, Kwang S. American Chemical Society 2016 ACS NANO Vol.10 No.1
<P>The study of electrochemical behavior of bioactive molecules has become one of the most rapidly developing scientific fields. Biotechnology and biomedical engineering fields have a vested interest in constructing more precise and accurate voltammetric/amperometric biosensors. One rapidly growing area of biosensor design involves incorporation of carbon-based nanomaterials in working electrodes, such as one-dimensional carbon nanotubes, two-dimensional graphene, and graphene oxide. In this review article, we give a brief overview describing the voltammetric techniques and how these techniques are applied in biosensing, as well as the details surrounding important biosensing concepts of sensitivity and limits of detection. Building on these important concepts, we show how the sensitivity and limit of detection can be tuned by including carbon-based nanomaterials in the fabrication of biosensors. The sensing of biomolecules including glucose, dopamine, proteins, enzymes, uric acid, DNA, RNA, and 11202 traditionally employs enzymes in detection; however, these enzymes denature easily, and as such, enzymeless methods are highly desired. Here we draw an important distinction between enzymeless and enzyme-containing carbon-nanomaterial-based biosensors. The review ends with an outlook of future concepts that can be employed in biosensor fabrication, as well as limitations of already proposed materials and how such sensing can be enhanced. As such, this review can act as a roadmap to guide researchers toward concepts that can be employed in the design of next generation biosensors, while also highlighting the current advancements in the field.</P>
Tiwari, Jitendra N.,Lee, Wang Geun,Sultan, Siraj,Yousuf, Muhammad,Harzandi, Ahmad M.,Vij, Varun,Kim, Kwang S. American Chemical Society 2017 ACS NANO Vol.11 No.8
<P>A key challenge in developing fuel cells is the fabrication of low-cost electrocatalysts with high activity and long durability for the two half-reactions, i.e., the methanol/ethanol oxidation reaction (MOR/EOR) and the oxygen reduction reaction (ORR). Herein, we report a conductivity-enhanced bifunctional electrocatalyst of nanoscale-coated Pt-Pd alloys on both tin-doped indium (TDI) and reduced graphene oxide (rGO), denoted as Pt-Pd@TDI/rGO. The mass activities of Pt in the Pt-Pd@TDI/rGO hybrid toward MOR, EOR, and ORR are 2590, 1500, and 2690 mA/mg, respectively. The ORR Pt specific activity and mass activity of the electrocatalyst are 17 and 28 times larger, respectively, than commercial Pt/C catalysts. All these remarkable catalytic performances are attributed to the role of TDI in enhancing the catalytic activity,by protecting Pt from oxidation as well as rapid mass/charge transfer due to the synergistic effect between surface Pt-Pd alloys and TDI/rGO.</P>
N. Tiwari,S. B. Singh,M. Ram 한국신뢰성학회 2010 International Journal of Reliability and Applicati Vol.11 No.2
This paper deals with the reliability analysis of a complex system, which consists of two subsystems A and B connected in series. Subsystem A has only one unit and B has two units B1 and B2. Marked process has been applied to model the complex system. Present reliability model incorporated two repairmen: supervisor and novice to repair the failed units. Supervisor is always there and the novice remains in vacation and is called for repair as per demand. The repair rates for supervisor and novice follow general and exponential distributions respectively and the failure time for both the subsystems follows exponential distribution. The model is analyzed under “Head of line repair discipline”. By employing supplementary variable technique, Laplace transformation and Gumbel-Hougaard family of copula various transition state probabilities, reliability, availability and cost analysis have been obtained along with the steady state behaviour of the system. At the end some special cases of the system have been taken.
Liao, N.,Unnithan, A.R.,Joshi, M.K.,Tiwari, A.P.,Hong, S.T.,Park, C.H.,Kim, C.S. Elsevier 2015 Colloids and surfaces. A, Physicochemical and engi Vol.469 No.-
<P>Electrospun nanofibrous mat for wound dressing application was successfully prepared from poly (6caprolactone) (PCL), cellulose acetate (CA) and dextran blend solution. Incorporation of small amount of tetracycline hydrochloride (TCH), an antibacterial drug, improved the cell proliferation, enhanced blood clotting ability and cell attachment as well as antimicrobial activity of the composite mat. The composite mats were characterized by SEM, FTIR and TGA analysis. In order to evaluate the cytocompatibility and cell behavior of the composite scaffolds, fibroblast cells were seeded on the matrix. Results demonstrated that the incorporation of dextran and drug strongly enhanced the adhesion and proliferation of the cells on the composite nanofibers. The antimicrobial activity of the composite was studied by zone inhibition against Gram-positive and Gram-negative bacteria and the result indicates high antibacterial activity. Therefore, as synthesized composite fiber have decent characteristics for wound dressing and skin engineering applications. (C) 2015 Elsevier B.V. All rights reserved.</P>
Georgakilas, Vasilios,Tiwari, Jitendra N.,Kemp, K. Christian,Perman, Jason A.,Bourlinos, Athanasios B.,Kim, Kwang S.,Zboril, Radek American Chemical Society 2016 Chemical reviews Vol.116 No.9
<P>This Review focuses on noncovalent functionalization of graphene and graphene oxide with various species involving biomolecules, polymers, drugs, metals and metal oxide-based nanoparticles, quantum dots, magnetic nanostructures, other carbon allotropes (fullerenes, nanodiamonds, and carbon nanotubes), and graphene analogues (MoS2, WS2). A brief description of pi-pi interactions, van der Waals forces, ionic interactions, and hydrogen bonding allowing noncovalent modification of graphene and graphene oxide is first given. The main part of this Review is devoted, to tailored functionalization for applications in drug delivery, energy materials, solar cells, water splitting, biosensing, bioimaging, environmental, catalytic, photocatalytic, and biomedical technologies. A significant part of this Review explores the possibilities of graphene/graphene oxide-based 3D superstructures and their use in lithium-ion batteries. This Review ends with a look at challenges and future prospects of noncovalently modified graphene and graphene oxide.</P>