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3D yolk-shell NiGa2S4 microspheres confined with nanosheets for high performance supercapacitors
Liu, S.,Kim, K.,Yun, J.,Kundu, A.,Sankar, K. V.,Patil, U.,Ray, C.,ChanJun, S. Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.13
<P>Recent advances in the development of two-dimensional transition-metal chalcogenides (2D TMCs) have opened up new avenues for supercapacitor applications. However, they still suffer from limited specific capacitance and poor rate capability due to their poor interfacial properties and simple geometry. Here, we propose a facile strategy for the synthesis of yolk-shell NiGa2S4 microspheres comprising crumpled nanosheets supported on nickel foam. The robust structure not only highly facilitates the electron and charge transportation but also efficiently alleviates the volume expansion during redox reactions, contributing to excellent electrochemical behaviors in terms of specific capacitance and rate capability. Significantly, an asymmetric supercapacitor based on the prepared NiGa2S4 as the positive electrode and N, S-codoped graphene/Fe2O3 (N, S-G/Fe2O3) as the negative electrode delivers a high energy density of 43.6 W h kg(-1) at a power density of 961 W kg(-1) and retains an energy density of 22.2 W h kg(-1) even at 15 974 W kg(-1). These impressive results may provide a new perspective to develop high energy and power density storage systems for practical applications.</P>
Liu, S.,Lee, S.,Patil, U.,Ray, C.,Sankar, K. V.,Zhang, K.,Kundu, A.,kang, S.,Park, J.,ChanJun, S. Royal Society of Chemistry 2017 Journal of Materials Chemistry A Vol.5 No.9
<P>NiO has been intensively studied as a promising electrode material for supercapacitors because of its high theoretical specific capacitance, well-defined redox behavior, and good chemical compatibility with nickel foam. However, it still suffers from inferior rate capability and cycling stability because of the simple component and random structural integration. Herein, we report a tunable sulfuration process of NiO nanosheets constructed on porous nickel foam for supercapacitor applications. The resulting NiO/Ni3S2 with distinct structural features exhibits an ultra-high specific capacitance of 2153 F g(-1) at a current density of 1 A g (1), and the capacitance is retained at 1169 F g (1) even at a current density as high as 30 A g (1). An asymmetric supercapacitor device fabricated with NiO/Ni3S2 as the positive electrode and activated carbon as the negative electrode delivers high energy and power densities (52.9 W h kg(-1) at 1.6 kW kg(-1); 26.3 W h kg(-1) at 6.4 kW kg(-1)), and good cycling stability (a capacitance retention of 92.9% over 5000 cycles).</P>
Ahn, B-C,Ronald, J A,Kim, Y I,Katzenberg, R,Singh, A,Paulmurugan, R,Ray, S,Hofmann, L V,Gambhir, S S Macmillan Publishers Limited 2011 Gene therapy Vol.18 No.6
Ideal cancer gene therapies should have high tumor specificity and efficacy, and allow systemic administration to target metastases. We recently developed a bi-directional, two-step transcriptional amplification (TSTA) system driven by the tumor-specific Survivin promoter (pSurv) to amplify the correlated expression of both the reporter gene firefly luciferase (FL) and therapeutic gene tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Here, we compare the specificity and potency of an adenovirus carrying this system (Ad-pSurv-TSTA-TRAIL-FL) to a nonspecific vector (Ad-pCMV-FL) in an orthotopic hepatocellular carcinoma (HCC) rat model after systemic administration. At 24 h after injection of Ad-pCMV-FL, bioluminescence imaging revealed a trend (P=0.30) towards greater FL expression in liver versus tumor. In striking contrast, Ad-pSurv-TSTA-TRAIL-FL showed increased FL activity within the tumor compared with the liver (P<0.01), a strong trend towards reduced liver expression compared with Ad-pCMV-FL (P=0.07), and importantly, similar FL levels within tumor compared with Ad-pCMV-FL (P=0.32). Hence, this vector shows potent, tumor-specific transgene expression even after extensive liver transduction and may be of significant value in avoiding hepatotoxicity in HCC patients. Future studies will explore the benefits of tumor-specific TRAIL expression in this model, the potential to target metastases and the extension of this vector for the treatment of other Survivin-positive tumors is warranted.
The genome of the extremophile crucifer Thellungiella parvula
Dassanayake, Maheshi,Oh, Dong-Ha,Haas, Jeffrey S,Hernandez, Alvaro,Hong, Hyewon,Ali, Shahjahan,Yun, Dae-Jin,Bressan, Ray A,Zhu, Jian-Kang,Bohnert, Hans J,Cheeseman, John M Nature Publishing Group, a division of Macmillan P 2011 Nature genetics Vol.43 No.9
Thellungiella parvula is related to Arabidopsis thaliana and is endemic to saline, resource-poor habitats, making it a model for the evolution of plant adaptation to extreme environments. Here we present the draft genome for this extremophile species. Exclusively by next generation sequencing, we obtained the de novo assembled genome in 1,496 gap-free contigs, closely approximating the estimated genome size of 140 Mb. We anchored these contigs to seven pseudo chromosomes without the use of maps. We show that short reads can be assembled to a near-complete chromosome level for a eukaryotic species lacking prior genetic information. The sequence identifies a number of tandem duplications that, by the nature of the duplicated genes, suggest a possible basis for T. parvula's extremophile lifestyle. Our results provide essential background for developing genomically influenced testable hypotheses for the evolution of environmental stress tolerance.
Wafer-scale synthesis of monolayer two-dimensional porphyrin polymers for hybrid superlattices
Zhong, Yu,Cheng, Baorui,Park, Chibeom,Ray, Ariana,Brown, Sarah,Mujid, Fauzia,Lee, Jae-Ung,Zhou, Hua,Suh, Joonki,Lee, Kan-Heng,Mannix, Andrew J.,Kang, Kibum,Sibener, S. J.,Muller, David A.,Park, Jiwoon American Association for the Advancement of Scienc 2019 Science Vol.366 No.6471
<P><B>Single-layer porphyrin polymerization</B></P><P>Two-dimensional polymers can be made as monolayer sheets through controlled synthesis at an interface. However, it is often difficult to create intact sheets over large areas that can be transferred onto substrates. Zhong <I>et al.</I> polymerized derivatized porphyrin molecules during laminar flow at a sharp pentane-water interface to form sheets that are 5 centimeters in diameter (see the Perspective by MacLean and Rosei). The authors used electron microscopy and spectroscopy to confirm that they had produced intact monolayers. These films were then transferred onto monolayer sheets of molybdenum disulfide to form superlattices for use as capacitors.</P><P><I>Science</I>, this issue p. 1379; see also p. 1308</P><P>The large-scale synthesis of high-quality thin films with extensive tunability derived from molecular building blocks will advance the development of artificial solids with designed functionalities. We report the synthesis of two-dimensional (2D) porphyrin polymer films with wafer-scale homogeneity in the ultimate limit of monolayer thickness by growing films at a sharp pentane/water interface, which allows the fabrication of their hybrid superlattices. Laminar assembly polymerization of porphyrin monomers could form monolayers of metal-organic frameworks with Cu<SUP>2+</SUP> linkers or covalent organic frameworks with terephthalaldehyde linkers. Both the lattice structures and optical properties of these 2D films were directly controlled by the molecular monomers and polymerization chemistries. The 2D polymers were used to fabricate arrays of hybrid superlattices with molybdenum disulfide that could be used in electrical capacitors.</P>
Role of an oxide interface in a resistive switch
Kumari Karuna,Kar Subhasmita,Thakur Ajay D.,Ray S.J. 한국물리학회 2022 Current Applied Physics Vol.35 No.-
In the present era of data-driven architectures like 5G, Internet of things (IoT), Artificial Intelligence (AI), etc, the requirement of fast-switchable memory storage is more than ever. Oxide resistive switches are considered to be a primary choice in the non-volatile memory design. In this work, we have engineered the conventional metal-insulator-metal (MIM) structure of an oxide memristor (Ag/ZnO/ITO) by inducing an additional oxide layer La0.7Sr0.3MnO3 (LSMO) at the interface between the active layer (ZnO) and Ag electrode. The presence of LSMO acts as a reservoir for the oxygen vacancies, easing the conducting filament formation process in ZnO, thereby enabling drastic improvement of the switching performance and offering reliable endurance over multiple switching cycles. First-principles-based calculations suggested the role of oxygen vacancies in controlling the electronic state of ZnO and formation of vacancies in the resistive switching process, which is in agreement with the experimental observation. The current results pave ways for improving the switching performance of resistive memory circuits through simple structural engineering incorporation, which lies at the heart of oxide electronics.
Interferometric constraints on quantum geometrical shear noise correlations
Chou, Aaron,Glass, Henry,Richard Gustafson, H,Hogan, Craig J,Kamai, Brittany L,Kwon, Ohkyung,Lanza, Robert,McCuller, Lee,Meyer, Stephan S,Richardson, Jonathan W,Stoughton, Chris,Tomlin, Ray,Weiss, Rai IOP 2017 Classical and quantum gravity Vol.34 No.16
<P>Final measurements and analysis are reported from the first-generation Holometer, the first instrument capable of measuring correlated variations in space-time position at strain noise power spectral densities smaller than a Planck time. The apparatus consists of two co-located, but independent and isolated, 40 m power-recycled Michelson interferometers, whose outputs are cross-correlated to 25 MHz. The data are sensitive to correlations of differential position across the apparatus over a broad band of frequencies up to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with Planck precision the correlation of position variations at spacelike separations, the Holometer searches for faint, irreducible correlated position noise backgrounds predicted by some models of quantum space-time geometry. The first-generation optical layout is sensitive to quantum geometrical noise correlations with shear symmetry—those that can be interpreted as a fundamental noncommutativity of space-time position in orthogonal directions. General experimental constraints are placed on parameters of a set of models of spatial shear noise correlations, with a sensitivity that exceeds the Planck-scale holographic information bound on position states by a large factor. This result significantly extends the upper limits placed on models of directional noncommutativity by currently operating gravitational wave observatories.</P>