30 research outputs found
Supplemental material for Subacute Transplantation of Native and Genetically Engineered Neural Progenitors Seeded on Microsphere Scaffolds Promote Repair and Functional Recovery After Traumatic Brain Injury
No full textSupplemental Material for Subacute Transplantation of Native and Genetically Engineered Neural Progenitors Seeded on Microsphere Scaffolds Promote Repair and Functional Recovery After Traumatic Brain Injury by Nolan B. Skop, Sweta Singh, Henri Antikainen, Chaitali Saqcena, Frances Calderon, Deborah E. Rothbard, Cheul H. Cho, Chirag D. Gandhi, Steven W. Levison and Radek Dobrowolski in ASN Neuro</p
Transfer-Free, Large-Scale Growth of High-Quality Graphene on Insulating Substrate by Physical Contact of Copper Foil
No full textHigh-quality, large-area, single-layer graphene was directly grown on top of a quartz substrate by a low-pressure chemical vapor deposition (CVD) process using Cu vapor as a catalyst. In this process, continuous generation and supply of highly concentrated Cu vapor is the key to the growth of largescale, high-quality graphene. It was achieved by direct physical contact, or "touch-down," of a Cu foil with an underlying sacrificial SiO2/Si substrate, and the target quartz substrate was placed on top of the Cu foil, eventually having a quartz/Cu/SiO2/Si sandwich structure. To establish the reaction mechanism, a test growth was performed without the quartz substrate, which revealed that Cu is diffused through the SiO2 layer of the sacrificial SiO2/Si substrate to form liquid-phase Cu-Si alloy that emits massive Cu vapor. This Cu vapor catalyzes thermal decomposition of supplied CH4 gas.11Nsciescopu
Direct observation of the M2 phase with its Mott transition in a VO2 film
No full textIn VO2, the explicit origin of the insulator-to-metal transition is still disputable between Peierls and Mott insulators. Along with the controversy, its second monoclinic (M2) phase has received considerable attention due to the presence of electron correlation in undimerized vanadium ions. However, the origin of the M2 phase is still obscure. Here, we study a granular VO2 film using conductive atomic force microscopy and Raman scattering. Upon the structural transition from monoclinic to rutile, we observe directly an intermediate state showing the coexistence of monoclinic M1 and M2 phases. The conductivity near the grain boundary in this regime is six times larger than that of the grain core, producing a donut-like landscape. Our results reveal an intra-grain percolation process, indicating that VO2 with the M2 phase is a Mott insulator. © 2016 Author(s6
Germanium Silicon Alloy Anode Material Capable of Tunable Overpotential by Nanoscale Si Segregation
No full textWe developed the novel electrode that enables fine control of overpotential by exploiting surface segregation that is the enrichment of one component at the surface of binary alloy. To realize this approach, we controlled the proportion of Si with low Li diffusivity at the surface by annealing the SiGe nanowire in H-2 environment at various temperatures. The resulting SiGe nanowires annealed at 850 degrees C exhibited high reversible capacity (>1031 mA.h.g(-1)), and long cycle life (400 cycles) with high opacity retention (89.0%) at 0.2 C. This superior battery performance is attributed to the remaining unlithiated part acting as support frame to prevent pulverization of anode material, which results from the fine-tuning of overpotential by controlling the degree of Si segregation.close0
Adhesive-tape soft lithography for patterning mammalian cells: application to wound-healing assays
No full textThis paper introduces a benchtop method for patterning mammalian cells—i.e., for culturing cells at specific locations—on planar substrates. Compared with standard cell culture techniques, which do not allow the control of what areas of a monolayer are populated by one type of cell or another, techniques of cell patterning open new routes to cell biology. Researchers interested in cell patterning, however, are oftentimes hindered by limited access to photolithographic capabilities. This paper shows how cells can be patterned easily with sub-millimeter precision using a non-photolithographic technique that is based on the use of office adhesive tape and poly(dimethylsiloxane) (PDMS). This method is fast (∼4 h to go from a layout to have the cells patterned in the shape of such layout) and only requires materials and tools readily available in a conventional biomedical laboratory. A wound-healing assay is presented here that illustrates the potential of the technique (which we call tape-based soft lithography) for patterning mammalian cells and studying biologically significant questions such as collective cellular migration
Nanocomb Architecture Design Using Germanium Selenide as High-Performance Lithium Storage Material
No full textA key to improve the electrochemical performance of anode materials is to exploit the rational nanostructure designing beneficial for structural toughness and high rate capability. As a nanostructure design in accordance with this criterion, we introduced GeSe nanocomb architecture with well-developed nanocomb teeth on the backbone. In this unique nanocomb architecture, the free space between nanocomb teeth effectively alleviates tremendous volume expansion during lithiation, and anisotropic structure with a short Li+ diffusion length of tens of nanometer scale guarantees the favorable lithiation/delithiation kinetics. These structural advantages of GeSe nanocomb architecture lead to significantly improved electrochemical performance compared to the GeSe nanopowder counterpart. This GeSe nanocomb architecture exhibits electrochemical performance with the reversible capacity of 726 mA.h.g(-1), showing superior capacity retention of 89% even after 1000 cycles at 1.0 C (1.01 A.g(-1)).clos
Catalyst-free direct growth of a single to a few layers of graphene on a germanium nanowire for the anode material of a lithium battery
No full textDirect growth of a single to a few layers of graphene on a germanium nanowire (Gr/Ge NW; see picture) was achieved by a metal-catalyst-free chemical vapor deposition (CVD) process. The Gr/Ge NW was used as anode in a lithium ion battery. This material has a specific capacity of 1059mA h g-1 at 4.0C, a long cycle life over 200 cycles, and a high capacity retention of 90 %.close1
Electrospun chitosan-based nanofiber scaffolds for cardiac tissue engineering applications
No full textDomain engineering of the metastable domains in the 4f-uniaxial-ferromagnet CeRu2 Ga2B
Get PDFIn search of novel, improved materials for magnetic data storage and spintronic devices, compounds that allow a tailoring of magnetic domain shapes and sizes are essential. Good candidates are materials with intrinsic anisotropies or competing interactions, as they are prone to host various domain phases that can be easily and precisely selected by external tuning parameters such as temperature and magnetic field. Here, we utilize vector magnetic fields to visualize directly the magnetic anisotropy in the uniaxial ferromagnet CeRu2Ga2B. We demonstrate a feasible control both globally and locally of domain shapes and sizes by the external field as well as a smooth transition from single stripe to bubble domains, which opens the door to future applications based on magnetic domain tailoring. ? 2017 The Author(s).113sciescopu
