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

Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of ‘gilding the (nanomedicinal) lily’, but that a new ‘Golden Age’ of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).

The golden age: gold nanoparticles for biomedicine

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

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Present and Future of Surface-Enhanced Raman Scattering

Pseudomonas aeruginosa (P. aeruginosa) is the common infection-causing bacterial pathogen. Conventional methods for the detection of P. aeruginosa are time-consuming, and therefore, a more rapid analytical method is required. Here, monoclonal antibodies (Mabs) against P. aeruginosa (CICC 10419) were prepared and based on paired Mabs, an immunochromatographic assay (ICA) was developed. The ICA strip showed a limit of detection of 2.41 × 104 CFU/mL and the linear range of detection was 3.13 × 104-1.0 × 106 CFU/mL. No cross-reactivity was observed when other common Gram-negative and Gram-positive bacteria were used. The analytical performance of the ICA strip indicated that the developed ICA had good specificity and stability. Moreover, the feasibility of the ICA strip was verified by detecting P. aeruginosa (CICC 10419) in spiked water and food samples. The ICA strip could detect samples contaminated with a low-level of P. aeruginosa (CICC 10419) after 8 h enrichment.

Gold nanoparticle-based immunochromatographic assay for detection Pseudomonas aeruginosa in water and food samples.

Magnesium-organic framework modified biodegradable electrospun scaffolds for promoting osteogenic differentiation and bone regeneration

The invention relates to a method for synthesizing artificial antigen having aminoglycoside medicine multi-antigen determinant, belonging to the biochemical engineering technical field. The method uses neomycin, kanamycin and gentamicin as hapten, uses a carbodiimide method to couple the hapten with protein bovine serum protein BSA as a carrier, and uses a gel electrophoresis method to measure the coupling ratio of coupled matter. The method successfully synthesizes the artificial antigen having the aminoglycoside medicine multi-antigen determinant, is simple and effective in synthesis method, can be used in immune analysis completely, provides the necessary artificial antigen for after research of people, and can meet the needs of the research on the aminoglycoside medicine in China.

Synthesis of multi-antigenic determinant artificial antigen with aminoglycoside medicaments

Textile reinforced composites are extensively used in thermal protection engineering because of their outstanding mechanical and physical properties. Spread tow woven pierced composites (STWPs) are composed of fiber rods, a spread tow and a matrix with small air pores. In the experiment, the STWPs displayed improved thermal conductivities compared with traditional woven composites. Thermal conductivities in the in-plane and out-of-plane directions have increments of 18.7% and 16.7%, respectively. This is mainly attributed to the influence of the fiber volume fraction. Herein, three numerical models were constructed to predict the thermal conductivities of the matrix, spread tow and fiber rods, and as the input parameter of the mesoscale model. The curvature of the interlaced tow in the mesoscale model was defined considering that the spread tow is extremely light and thin. The predicted results are in accordance with the experimental results, with only 8.13% and 8.94% errors in the in-plane and out-of-plane directions, respectively, indicating that the numerical models are accurate and effective. In addition, the thermal conductivities of STWPs decrease with the increase of porosity, but increase with the increment in fiber volume fraction and interphase thermal conductance. This work can provide effective guidance for the thermal design of STWPs.

Chuanlai Xu

Papers

Gold nanoparticle-based immunochromatographic assay for detection Pseudomonas aeruginosa in water and food samples.

Magnesium-organic framework modified biodegradable electrospun scaffolds for promoting osteogenic differentiation and bone regeneration

Synthesis of multi-antigenic determinant artificial antigen with aminoglycoside medicaments

Numerical study on thermal conductivities of spread tow woven pierced composites

Walking another pathway: The inclusion of patterning in the pathways to mathematics model.