Interconnected Pt-Nanodendrite/DNA/Reduced-Graphene-Oxide Hybrid Showing Remarkable Oxygen Reduction Activity and Stability

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>

Titanium Dioxide Nanomaterials and its Derivatives in the Remediation of Water: Past, Present and Future

Tiwari, Alka,Shukla, Alok,Tiwari, Diwakar,Choi, Suk Soon,Shin, Hyun-Gon,Lee, Seung-Mok The Korean Society of Industrial and Engineering C 2019 공업화학 Vol.30 No.3

The aim of this review article is to summarize the role of titanium oxide ($TiO_2$) nanomaterials in the remediation of the aquatic environment contaminated with various emerging pollutants. The advanced oxidation process led by the semiconductor $TiO_2$ is an impetus in the remediation technology. Therefore, a vast number of literature works are available in this area. Further, the role of modified $TiO_2$ or thin film materials were discussed in the review. Also, the Localized Surface Plasmon Resonance (LSPR) effect of using noble metaldoped $TiO_2$ played an interesting role in the remediation process.

Au-nanoparticle/nanopillars TiO2 meso-porous thin films in the degradation of tetracycline using UV-A light

Alka Tiwari,Alok Shukla,Lalliansanga,Diwakar Tiwari,이승목 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

Novel meso-porous nanoparticles Au/TiO2 thin films were obtained by template synthesis using polyethylene glycol as filler medium. The materials were characterized by advanced analytical methods. The photocatalysts were employed for the photocatalytic degradation of tetracycline from aqueous solutions using UV-A light (λmax 330 nm). Various physico-chemical parametric studies enabled to deduce the mechanism of degradation. A significant percentage of tetracycline was mineralized by the treatment. The stability of thin film was evidenced with the repeated use of thin film. The degradation of tetracycline was proceeded predominantly by the OH radicals generated at the valance and conduction band of semiconductor.

Titanium Dioxide Nanomaterials and its Derivatives in the Remediation of Water: Past, Present and Future

( Alka Tiwari ),( Alok Shukla ),( Diwakar Tiwari ),( Suk Soon Choi ),( Hyun-gon Shin ),( Seung-mok Lee ) 한국공업화학회 2019 공업화학 Vol.30 No.3

The aim of this review article is to summarize the role of titanium oxide (TiO₂) nanomaterials in the remediation of the aquatic environment contaminated with various emerging pollutants. The advanced oxidation process led by the semiconductor TiO₂ is an impetus in the remediation technology. Therefore, a vast number of literature works are available in this area. Further, the role of modified TiO₂ or thin film materials were discussed in the review. Also, the Localized Surface Plasmon Resonance (LSPR) effect of using noble metaldoped TiO₂ played an interesting role in the remediation process.

Al based ultra-fine eutectic with high room temperature plasticity and elevated temperature strength

Tiwary, C.S.,Kashyap, S.,Kim, D.H.,Chattopadhyay, K. Elsevier Sequoia 2015 Materials science & engineering. properties, micro Vol.639 No.-

Developments of aluminum alloys that can retain strength at and above 250<SUP>o</SUP>C present a significant challenge. In this paper we report an ultrafine scale Al-Fe-Ni eutectic alloy with less than 3.5at% transition metals that exhibits room temperature ultimate tensile strength of ~400 MPa with a tensile ductility of 6-8%. The yield stress under compression at 300<SUP>o</SUP>C was found to be 150 MPa. We attribute it to the refinement of the microstructure that is achieved by suction casting in copper mold. The characterization using scanning and transmission electron microscopy (SEM and TEM) reveals an unique composite structure that contains the Al-Al<SUB>3</SUB>Ni rod eutectic with spacing of ~90nm enveloped by a lamellar eutectic of Al-Al<SUB>9</SUB>FeNi (~140nm). Observation of subsurface deformation under Vickers indentation using bonded interface technique reveals the presence of extensive shear banding during deformation that is responsible for the origin of ductility. The dislocation configuration in Al-Al<SUB>3</SUB>Ni eutectic colony indicates accommodation of plasticity in α-Al with dislocation accumulation at the α-Al/Al<SUB>3</SUB>Ni interface boundaries. In contrast the dislocation activities in the intermetallic lamellae are limited and contain set of planner dislocations across the plates. We present a detailed analysis of the fracture surface to rationalize the origin of the high strength and ductility in this class of potentially promising cast alloy.

Highly active and stable layered ternary transition metal chalcogenide for hydrogen evolution reaction

Tiwari, Anand P.,Kim, Doyoung,Kim, Yongshin,Prakash, Om,Lee, Hyoyoung Elsevier 2016 Nano energy Vol.28 No.-

<P><B>Abstract</B></P> <P>Layered ternary transition metal chalcogenides (TTMCs) material has great potentials that can overcome to the limitation of active sites which is challenging in binary transition metal chalcogenides (BTMC), such as MoS<SUB>2</SUB>, towards electrochemical hydrogen production. Here, we demonstrate TTMC material which contains two transition metals Cu and Mo with chalcogen S. The TTMC, Cu<SUB>2</SUB>MoS<SUB>4</SUB> has been successfully synthesized by a facile solution-processed method. Moreover, by anion doping such as Se in as the synthesized Cu<SUB>2</SUB>MoS<SUB>4</SUB>, it has been found that TTMC can be exfoliated into single layer nanosheets. Furthermore, by controlling the number of layers, single layers TTMC exhibit the highest electrocatalytic activity towards hydrogen evolution reaction (HER) because the single layers can provide more catalytic active sites than multilayers and bulk. The onset potential for hydrogen generation is −96mV for single layer TTMC electrode material with corresponding Tafel slope 52mV/decade. After 1000 cycles with continuous electrolysis in acid electrolyte for 15h, the electrode material preserves its structure and robust catalytic activity perfectly. Our new TTMC materials show highly active electrocatalytic performance and high stability which overcome the intrinsic limitation of BTMC. As a result, our work can guide new strategy for the developments of real applications of TMCs in HER.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Single layered ternary transition metal chalcogenides have been synthesized for highly active and stable electrocatalyst. </LI> <LI> Se-doping plays an essential role to exfoliate Cu<SUB>2</SUB>Mo(S<SUB>1-y</SUB>Se<SUB>y</SUB>)<SUB>4</SUB> for high electrochemical active surface. </LI> <LI> Se-doping strategy can be implemented to exfoliate and enhance electrocatalytic activity of transition metals chalcogens. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Effective approaches to synthesis of single layered ternary transition metal chalcogenide (TTMC) have been developed to produce highly active and stable electrocatalyst towards hydrogen evolution reaction. The single layered TTMC are achieved by Se-doping in Cu<SUB>2</SUB>MoS<SUB>4</SUB> which can be applicable for other transition metal chalcogenide (TMC).</P> <P>[DISPLAY OMISSION]</P>

Prevention of sulfur diffusion using MoS2-intercalated 3D-nanostructured graphite for high-performance lithium-ion batteries.

Tiwari, Anand P,Yoo, HeeJoun,Lee, JeongTaik,Kim, Doyoung,Park, Jong Hyeok,Lee, Hyoyoung RSC Pub 2015 Nanoscale Vol.7 No.28

<P>We report new three-dimensional (3D)-nanostructured MoS2-carbonaceous materials in which MoS2 sheets are intercalated between the graphite layers that possess a multiply repeated graphite/MoS2/graphite structure which prevents the aggregation of MoS2 and diffusion of sulfur from carbonaceous materials, enhancing the cycling stability of Li-ion batteries. We developed an efficient and scalable process applicable to mass production for synthesizing non-aggregated MoS2-intercalated 3D hybrid-nanostructured graphite based on stress induced and microwave irradiation. X-ray diffraction, X-ray photospectroscopy, Raman spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy analyses demonstrated that the as-synthesized materials consisted of MoS2-intercalated 3D hybrid-nanostructured graphite platelets that had a multiply repeated graphite/MoS2/graphite structure. The obtained MoS2-graphite powder surpasses MoS2 as an anode material in terms of specific capacity, cyclic stability, and rate performances at high current densities for Li-ion batteries. The electrochemical impedance spectroscopy demonstrated that the graphite sheets not only reduced the contact resistance in the electrode but also facilitated electron transfer in the lithiation/delithiation processes. The superior electrochemical performances especially for the cycling stability of the Li-ion battery originate from prevention of the sulfur diffusion of the MoS2-intercalated 3D-nanostructured graphite.</P>

An Unusual Presentation of Rectal Carcinoma in a Child

Tiwari, Charu,Zadpe, Ashish,Rathi, Pravin,Shah, Hemanshi The Korean Society of Pediatric Gastroenterology 2018 Pediatric gastroenterology, hepatology & nutrition Vol.21 No.1

Colorectal carcinoma is a well-known malignancy in adults. However, it is rare in children. Besides, it also has different behaviour in paediatric age-group and usually presents with non-specific symptoms like abdominal pain, weight loss, and anaemia. This usually leads to delay in diagnosis. Adenocarcinoma in children has unfavourable tumour histology (mucinous subtype) and advanced disease stage at presentation which lead to poorer prognosis in children. Family history, genetic typing and sibling screening are essential components of management as this malignancy is frequently seen associated with hereditary syndromes. We describe a case of unusual presentation of rectal carcinoma in a 12-year-old girl.

Modulation of Inula racemosa Hook Extract on Cardioprotection by Ischemic Preconditioning in Hyperlipidaemic Rats

Tiwari Arun Kumar,Gupta Pushpraj S,Prasad Mahesh,Malairajan Paraman 대한약침학회 2022 Journal of pharmacopuncture Vol.25 No.4

Objectives: Hyperlipidemia (HL) is a major cause of ischemic heart diseases. The size-limiting effect of ischemic preconditioning (IPC), a cardioprotective phenomenon, is reduced in HL, possibly because of the opening of the mitochondrial permeability transition pore (MPTP). The objective of this study is to see what effect pretreatment with Inula racemosa Hook root extract (IrA) had on IPC-mediated cardioprotection on HL Wistar rat hearts. An isolated rat heart was mounted on the Langendorff heart array, and then ischemia reperfusion (I/R) and IPC cycles were performed. Atractyloside (Atr) is an MPTP opener. Methods: The animals were divided into ten groups, each consisting of six rats (n = 6), to investigate the modulation of I. racemosa Hook extract on cardioprotection by IPC in HL hearts: Sham control, I/R Control, IPC control, I/R + HL, I/R + IrA + HL, IPC + HL, IPC + NS + HL, IPC + IrA+ HL, IPC + Atr + oxidative stress, mitochondrial function, integrity, and hemodynamic parameters are evaluated for each group. Results: The present experimental data show that pretreatment with IrA reduced the LDH, CK-MB, size of myocardial infarction, content of cardiac collagen, and ventricular fibrillation in all groups of HL rat hearts. This pretreatment also reduced the oxidative stress and mitochondrial dysfunction. Inhibition of MPTP opening by Atr diminished the effect of IrA on IPC-mediated cardioprotection in HL rats. Conclusion: The study findings indicate that pretreatment with IrA e restores IPC-mediated cardioprotection in HL rats by inhibiting the MPTP opening.

Point-Wise Fusion of Distributed Gaussian Process Experts (FuDGE) Using a Fully Decentralized Robot Team Operating in Communication-Devoid Environment

Tiwari, Kshitij,Jeong, Sungmoon,Chong, Nak Young IEEE 2018 IEEE TRANSACTIONS ON ROBOTICS Vol.34 No.3

<P>In this paper, we focus on large-scale environment monitoring by utilizing a fully decentralized team of mobile robots. The robots utilize the resource constrained-decentralized active sensing scheme to select the most informative (uncertain) locations to observe while conserving allocated resources (battery, travel distance, <I>etc.</I>). We utilize a distributed Gaussian process (GP) framework to split the computational load over our fleet of robots. Since each robot is individually generating a model of the environment, there may be conflicting predictions for test locations. Thus, in this paper, we propose an algorithm for aggregating individual prediction models into a single globally consistent model that can be used to infer the overall spatial dynamics of the environment. To make a prediction at a previously unobserved location, we propose a novel gating network for a mixture-of-experts model wherein the weight of an expert is determined by the responsibility of the expert over the unvisited location. The benefit of posing our problem as a centralized fusion with a distributed GP computation approach is that the robots never communicate with each other, individually optimize their own GP models based on their respective observations, and off-load all their learnt models on the base station only at the end of their respective mission times. We demonstrate the effectiveness of our approach using publicly available datasets.</P>