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.

/pdf/mussel-inspired-surface-chemistry-for-multifunctional-1noq7vcby7.pdf

Mussel-Inspired Surface Chemistry for Multifunctional Coatings

/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

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

A new process to form fme pitch, high aspect ratio polymer flip chip bumps is described in this paper. Rather than conventional stencil printing, we produce the humps via a through-hole polydimethylsiloxane (PDMS) microtransfer mold (pTM) on a metallized wafer. Polymer bumping is achieved after silver epoxy paste is printed and cured inside the PDMS pTM which can be removed easily by solvent in subsequent steps. With this bumping approach, intrinsic slumping problem of the conductive polymer paste can be resolved. Complex circuit pattem and fme feature conductor can be built. In the current process evaluation, polymer humps of llOp diameter and 75p height were fabricated at 400p pitch. Electrical resistance measured between two bumps is ahout 1.OR. Depends on different paste deposition technique, bump shear strength varies from 20-1OOg. Shear strength of poor wetting hump is 23g. Average bump strength for good wetting bump is 83g which is comparable to reported value of solder joint [l]. This paper demonstrates the feasibility of fabricating conductive polymer flip chip bumps for fme pitch, high aspect ratio application at temperature 12OOC. Such low temperature fabrication technique is prevalent for MEMS packaging.

Using PDMS Microtransfer Molding (pTM) for Polymer Flip chip

An adhesion bond between a metallic surface layer and a second surface is formed by treating the layers with a material comprising sulphur-containing molecules. The sulphur-containing molecules are applied as a surface treatment of the surfaces, so that the sulphur-containing molecules act as a coupling agent to bond chemically to both substrates form nanometer-sized structures on the surfaces. The nanometer-sized structures are incorporated into a self-assembly interlayer in between the surfaces, with the interlayer forming a bond to both surfaces.

/pdf/implementing-self-assembly-nanometer-sized-structures-within-5ctqy3wcoa.pdf

Implementing self-assembly nanometer-sized structures within metal—polymer interface

Here we show the first example of an immunoreceptor tyrosine-based inhibitory motif (ITIM), LYYYYL, as well as its enantiomeric or retro-inverso peptide, to self-assemble in water via enzyme-instructed self-assembly. Upon enzymatic dephosphorylation, the phosphohexapeptides become hexapeptides, which self-assemble in water to result in supramolecular hydrogels. This work illustrates a new approach to design bioinspired soft materials from a less explored, but important pool of immunomodulatory peptides.

/pdf/enzymatic-self-assembly-of-an-immunoreceptor-tyrosine-based-7ruczx37o9.pdf

Enzymatic self-assembly of an immunoreceptor tyrosine-based inhibitory motif (ITIM)

Enzymatic Delivery of Magnetic Nanoparticles into Mitochondria of Live Cells

Disclosed is a general methodology to create nano fibers of therapeutic molecules that have a dual role, as both the delivery vehicle and the drug itself. It is shown that with proper molecular design, the integration of enzymatic reaction and self-assembly provides a powerful method to create molecular hydrogels of clinically-used therapeutics without compromising their bioactivities. In addition, the results disclosed herein demonstrate enzyme-instructed self-assembly as a facile strategy for generating the supramolecular hydrogels of molecules that inherently have poor solubility in water. For example, by covalently connecting paclitaxel with a motif that is prone to self-assemble, a hydrogel of paclitaxel can be formed without compromising the activity of the paclitaxel.

Bing Xu

Papers

Using PDMS Microtransfer Molding (pTM) for Polymer Flip chip

Implementing self-assembly nanometer-sized structures within metal—polymer interface

Enzymatic self-assembly of an immunoreceptor tyrosine-based inhibitory motif (ITIM)

Enzymatic Delivery of Magnetic Nanoparticles into Mitochondria of Live Cells

Antineoplastic Hydrogels, and Enzyme-Instructed Preparations Thereof