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.

Bioconjugated Au/Ag nanocages as a novel optical imaging contrast and thermal therapeutic agent

Abstract: We have synthesized 40-nm Au/Ag nanocages and explored their use as an optical imaging/spectroscopy contrast agent and potentially a thermal therapeutic agent. Cancer cell specific targeting by antibody-conjugated nanocages has also been demonstrated.

Polystyrene‐Silica Colloidal Janus Particles with Uniform Shapes and Complex Structures

Abstract: Colloidal Janus particles with well‐controlled parameters are sought for a range of applications in mesoscale self‐assembly, stabilization of Pickering emulsion, and development of multifunctional devices, among others. Herein, a versatile method for fabricating polystyrene‐silica (PS‐SiO2) Janus particles featuring complex shapes and structures is developed by swelling PS@SiO2 core–shell spheroids. When the PS encapsulated in a rigid SiO2 shell is swollen by a good solvent for PS, the swelling‐induced pressure will result in an uneven distribution of stress acting on the SiO2 shell, as determined by the intrinsic symmetry of a spheroid. When the stress reaches a threshold value, the swollen PS will preferentially poke out from equatorial sites on the SiO2 shell to form T‐shaped Janus particles comprised of PS and SiO2 compartments. The size of the PS portion can be controlled by varying the extent of swelling, while the size, shape, and shell thickness of the SiO2 portion are determined by the original PS spheroids and the SiO2 coating. This solution‐phase method holds promise to produce Janus particles with diverse shapes, structures, and compositions for various applications. The T‐shaped Janus particles can serve as an emulsifier to effectively stabilize an oil‐in‐water (O/W) Pickering emulsion for at least 35 days.

Fast parallel algorithms for short-range molecular dynamics

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.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

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。

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

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