There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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.

Fast parallel algorithms for short-range molecular dynamics

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。

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

We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules.

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Mussel-Inspired Surface Chemistry for Multifunctional Coatings

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Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

In this study, we report multi-component supramolecular hydrogels that exhibit exceptional high storage moduli and a rapid recovery of their original mechanical strength after removing external forces. The formation of such kind of supramolecular hydrogels is simple and versatile, and the components can be easily synthesized or commercially available in large quantities. The supramolecular hydrogels have been characterized by SEM and fluorescence spectrometry and the results obtained by both techniques correlate well with their mechanical properties. They have potential to be developed into useful materials that require high mechanical stiffness and possess rapid recovery properties, such as the injectable immobilization matrix for cells culture, drug release, enzyme encapsulation, etc.

Phenyl groups in supramolecular nanofibers confer hydrogels with high elasticity and rapid recovery

Here, for the first time, we present a new approach to produce peptide nanoparticles, which involves controlling the self-assembly process with an enzymatic trigger and confining it within nanoscale reverse micelles.

Controlling self-assembly within nanospace for peptide nanoparticle fabrication

Using soft lithography to pattern highly oriented polyacetylene (HOPA) films via solventless polymerization

Cell-mediated remodeling of extracellular matrix (ECM) plays important roles for cell functions, but it is challenging to develop synthetic materials for mimicking such a dynamic aspect of proteins in ECM. Here we show that intercellular morphological transition of peptide assemblies mimic the unfolding of fibronectin, thus enabling formation of spheroids from a monolayer of cells. Specifically, the phosphopeptide self-assembles to form nanoparticles, which turns into nanofibers upon partial dephosphorylation catalyzed by enzymes (e.g., phosphatases) at intercellular space. Occurring between HS-5 cells, such an enzyme-instructed self-assembly enables a sheet of the HS-5 cells to form cell spheroids. Structure-activity investigation reveals that proteolytic stability, dephosphorylation, and biotin conjugation of the peptides are indispensable for forming the cell spheroids. Further mechanism study indicates that the intercellular assemblies interact with multiple ECM components (e.g., laminin, collagens III and IV) to drive the formation of the cell spheroids. As the first example of intercellular instructed-assembly from homotypic precursors, this work illustrates a new approach that uses cell-responsive peptide assemblies to mimic protein dynamics for control cell behaviors.

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Intercellular Instructed-Assembly Mimics Protein Dynamics To Induce Cell Spheroids.

We report the evaluation of cytotoxicity of a new type of engineered nanomaterials, FePt@CoS(2) yolk-shell nanocrystals, synthesized by the mechanism of the Kirkendall effect when FePt nanoparticles serve as the seeds. The cytotoxicity of FePt@CoS(2) yolk-shell nanocrystals, evaluated by MTT assay, shows a much lower IC(50) (35.5 +/- 4.7 ng of Pt/mL for HeLa cell) than that of cisplatin (230 ng of Pt/mL). In the control experiment, cysteine-modified FePt nanoparticles exhibit IC50 at 12.0 +/- 0.9 microg of Pt/mL. Transmission electron microscopy confirms the cellular uptake of FePt@CoS(2) nanocrystals, and the magnetic properties analysis (SQUID) proves the release of FePt nanoparticles from the yolk-shell nanostructures after cellular uptake. These results are significant because almost none of the platinum-based complexes produced for clinical trials in the past 3 decades have shown higher activity than that of the parent drug, cisplatin. The exceptionally high toxicity of FePt@CoS(2) yolk-shell nanocrystals (about 7 times higher than that of cisplatin in terms of Pt) may lead to a new design of an anticancer nanomedicine.

Bing Xu

Papers

Phenyl groups in supramolecular nanofibers confer hydrogels with high elasticity and rapid recovery

Controlling self-assembly within nanospace for peptide nanoparticle fabrication

Using soft lithography to pattern highly oriented polyacetylene (HOPA) films via solventless polymerization

Intercellular Instructed-Assembly Mimics Protein Dynamics To Induce Cell Spheroids.

FePt@CoS2 Yolk—Shell Nanocrystals as a Potent Agent to Kill HeLa Cells.