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

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

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

The intrinsic limits of conventional cancer therapies prompted the development and application of various nanotechnologies for more effective and safer cancer treatment, herein referred to as cancer nanomedicine. Considerable technological success has been achieved in this field, but the main obstacles to nanomedicine becoming a new paradigm in cancer therapy stem from the complexities and heterogeneity of tumour biology, an incomplete understanding of nano-bio interactions and the challenges regarding chemistry, manufacturing and controls required for clinical translation and commercialization. This Review highlights the progress, challenges and opportunities in cancer nanomedicine and discusses novel engineering approaches that capitalize on our growing understanding of tumour biology and nano-bio interactions to develop more effective nanotherapeutics for cancer patients.

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Cancer nanomedicine: progress, challenges and opportunities.

This Perspective explores and explains the fundamental dogma of nanoparticle delivery to tumours and answers two central questions: ‘how many nanoparticles accumulate in a tumour?’ and ‘how does this number affect the clinical translation of nanomedicines?’

/pdf/analysis-of-nanoparticle-delivery-to-tumours-kovi4y80u2.pdf

Analysis of nanoparticle delivery to tumours

The rise in nosocomial infections caused by multidrug-resistant pathogens is a major public health concern. Patients taking immunosuppressants or chemotherapeutics are naturally more susceptible to infections. Thus, strategies for protecting immunodeficient individuals from infections are of great importance. Here, we investigate the effectiveness of a biomimetic nanotoxoid vaccine in defending animals with immunodeficiency against Pseudomonas aeruginosa. The nanotoxoids use a macrophage membrane coating to sequester and safely present bacterial virulence factors that would otherwise be too toxic to administer. Vaccination with the nanoformulation results in rapid and long-lasting immunity, protecting against lethal infections despite severe immunodeficiency. The nanovaccine can be administered through multiple routes and is effective in both pneumonia and septicemia models of infection. Mechanistically, protection is mediated by neutrophils and pathogen-specific antibodies. Overall, nanotoxoid vaccination is an attractive strategy to protect vulnerable patients and could help to mitigate the threat posed by antibiotic-resistant superbugs.

/pdf/nanotoxoid-vaccination-protects-against-opportunistic-6p6cvpj8.pdf

Nanotoxoid vaccination protects against opportunistic bacterial infections arising from immunodeficiency

We performed a systematic study on the exchange bias in (1 1 0)-orientated Bi0.9La0.1FeO3/La0.5Ca0.5MnO3 (BLFO/LCMO) heterostructure with a fixed BLFO film thickness of 600 nm and different LCMO layers ranging from t=0 to 30 nm. The LCMO is found to be weakly ferromagnetic, with the Curie temperature descending from ∼225 K to 0 as the layer thickness decreases from 30 nm to 3 nm. The main magnetic contributions come from the BLFO film, and the areal magnetization ratio is 1:0.07 for t=5 nm and 1:0.82 for t=30 nm for BLFO to LCMO at the temperature of 5 K. Further experiments show the presence of significant exchange bias, and it is, at the temperature of 10 K, ∼40 Oe for t=0 and ∼260 Oe for t=30 nm. The exchange bias reduces dramatically upon warming and disappears above the blocking temperature of the spin-glasslike behavior observed in the samples. The possible origin for exchange bias is discussed.

http://m03.iphy.ac.cn/Paper/2012/PB407（2012）2773-M03.pdf

Exchange bias in (1 1 0)-orientated Bi0.9La0.1FeO3/La0.5Ca0.5MnO3 films

We performed a comprehensive study on the La1−xCaxMnO3/SrTiO3:Nb junctions with different hole content and film thickness. It is found that the interfacial barrier, which determines the physical properties of the junctions, shows a strong dependence on crystallographic orientation, and it is substantially higher for the (110) than for the (100)-orientated junctions. The difference in barrier height is further found to exhibit a systematic variation with Ca content and film thickness (t). It reduces from ∼0.09 to 0.02 eV for a x increase from 0.1 to 1 with a fixed t=200 nm, and experiences a growth by ∼0.06 eV corresponding to the variation in t from 10 to 160 nm for a constant x=0.33. Similar phenomena have been observed in the La0.67Ba0.33MnO3/SrTiO3:Nb junctions. In the scenario of different polarity mismatches at the (100) and (110) interfaces in the two series of junctions, these results can be qualitatively understood.

/pdf/interfacial-barrier-in-manganite-junctions-with-different-3ys7qncvws.pdf

Interfacial barrier in manganite junctions with different crystallographic orientations

We performed a systematic study on a Cu/La0.67Ba0.33MnO3/SrTiO3?:?Nb (Cu/LBMO/STON) junction with a manganite layer, a few unit cells in width, focusing on the evolution of Cu?STON coupling as the film thickness of LBMO grew. The physical properties of the junction are found to be jointly determined by the electrode, the film and the substrate when the film thickness of LBMO is below ~1?nm, with a carrier tunnelling process and a weakly rectifying feature. A LBMO film above ~1?nm completely screens the electrode?substrate interaction, enhancing the rectifying character of the junctions significantly. A further increase in film thickness leads only to a minor modification of the junctions.

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Physical properties of Cu/La0.67Ba0.33MnO3/SrTiO3 : Nb junctions with ultrathin manganite layers

Effects of the LaMnO3 (LMO) buffer layer on the magnetoresistive behaviors of La0.67A0.33MnO3/LaMnO3/SrTiO3:0.05 wt% Nb (LAMO/LMO/STON, A = Ca, Sr) have been experimentally studied. In addition to an enhanced response to a magnetic field, the current-voltage relations show a downward shift in magnetic field, indicating an increase of the junction resistance. It is completely different from that observed in the junctions without buffer layer. The positive magnetoresistance (MR) is strongly dependent on the thickness of the LMO layer, increasing first then decreasing with the increase of layer thickness. Furthermore, it is significantly stronger in LCMO/LMO/STON than in LSMO/LMO/STON. The maximal MR at 50 K is ∼90% for LCMO/LMO/STON and ∼52% for LSMO/LMO/STON, occurring at the LMO thickness of 4 nm under the field of 5 T. The MR persists up to 350 K, and it is ∼30% and ∼24% for the LCMO and LSMO junctions, respectively. An analysis of the current-voltage characteristics indicates an increase in interfacial ...

/pdf/buffer-layer-induced-positive-magnetoresistance-in-manganite-25twgw6vhr.pdf

Weiwei Gao

Papers

Nanotoxoid vaccination protects against opportunistic bacterial infections arising from immunodeficiency

Exchange bias in (1 1 0)-orientated Bi0.9La0.1FeO3/La0.5Ca0.5MnO3 films

Interfacial barrier in manganite junctions with different crystallographic orientations

Physical properties of Cu/La0.67Ba0.33MnO3/SrTiO3 : Nb junctions with ultrathin manganite layers

Buffer layer-induced positive magnetoresistance in manganite-based heterojunctions