scispace - formally typeset
Search or ask a question
Author

Younan Xia

Bio: Younan Xia is an academic researcher from The Wallace H. Coulter Department of Biomedical Engineering. The author has contributed to research in topics: Nanocages & Nanowire. The author has an hindex of 216, co-authored 943 publications receiving 175757 citations. Previous affiliations of Younan Xia include Washington University in St. Louis & University of Texas at Dallas.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, the authors discuss the self-assembly of one-dimensional, single-crystalline organic nanowires, show the structures of commonly employed organic semiconductors, and review some of the advances in this field.

358 citations

Journal ArticleDOI
TL;DR: A two-step procedure for generating cubic nanocages and nanoframes with relatively narrow SPR peaks by controlling the amount of HAuCl4 used for the galvanic replacement reaction and thus the optimization of the percentage of Au in the alloy nanoboxes is described.
Abstract: This paper describes a two-step procedure for generating cubic nanocages and nanoframes. In the first step, Au/Ag alloy nanoboxes were synthesized through the galvanic replacement reaction between Ag nanocubes and an aqueous HAuCl4 solution. The second step involved the selective removal (or dealloying) of Ag from the alloy nanoboxes with an aqueous etchant based on Fe(NO3)3 or NH4OH. The use of a wet etchant other than HAuCl4 for the dealloying process allows one to better control the wall thickness and porosity of resultant nanocages because there is no concurrent deposition of Au. By increasing the amount of Fe(NO3)3 or NH4OH added to the dealloying process, nanoboxes derived from 50-nm Ag nanocubes could be converted into nanocages and then cubic nanoframes with surface plasmon resonance (SPR) peaks continuously shifted from the visible region to 1200 nm. It is also possible to obtain nanocages with relatively narrow SPR peaks (with a full width at half-maximum as small as 180 nm) by controlling the amount of HAuCl4 used for the galvanic replacement reaction and thus the optimization of the percentage of Au in the alloy nanoboxes.

353 citations

Journal ArticleDOI
TL;DR: In this paper, a simple and convenient approach that allowed for the facial synthesis of silver/silica coaxial nanocables with well-controlled sheath thicknesses in the range of 2−100 nm was described.
Abstract: This paper describes a simple and convenient approach that allowed for the facial synthesis of silver/silica coaxial nanocables with well-controlled sheath thicknesses in the range of 2−100 nm. The lengths of these nanocables could be up to ∼50 μm. Such nanocables were prepared by directly coating bicrystalline silver nanowires with conformal sheaths of silica through a sol−gel process. The silver nanowires were, in turn, synthesized using a polyol method that involved the reduction of silver nitrate with ethylene glycol in the presence of poly(vinyl pyrrolidone). The thickness of silica coating could be controlled by changing the concentration of the precursor solution and/or the reaction time. Selective removal of the silver cores led to the formation of silica nanotubes having well-controlled dimensions and wall structures.

352 citations

Journal ArticleDOI
TL;DR: The localized surface plasmon resonance of a silver nanoparticle is responsible for its ability to strongly absorb and scatter light at specific wavelengths as discussed by the authors, and the absorption and scattering spectra of a particle can be predicted using Mie theory (for a spherical particle) or the discrete dipole approximation method (for particles in arbitrary shapes).
Abstract: The localized surface plasmon resonance of a silver nanoparticle is responsible for its ability to strongly absorb and scatter light at specific wavelengths. The absorption and scattering spectra (i.e., plots of cross sections as a function of wavelength) of a particle can be predicted using Mie theory (for a spherical particle) or the discrete dipole approximation method (for particles in arbitrary shapes). In this review, we briefly discuss the calculated spectra for silver nanoparticles with different shapes and the synthetic methods available to produce these nanoparticles. As validated in recent studies, there is good agreement between the theoretically calculated and the experimentally measured spectra. We conclude with a discussion of new plasmonic and sensing applications enabled by the shape-controlled nanoparticles.

351 citations


Cited by
More filters
01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: A review of gold nanoparticles can be found in this article, where the most stable metal nanoparticles, called gold colloids (AuNPs), have been used for catalysis and biology applications.
Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

11,752 citations