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

In this study, the monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic strip assay were developed for the rapid screening of robenidine hydrochloride (ROBH) in samples. The 50% inhibitory concentration (IC50) of ROBH was 0.927 ng mL-1, and the standard curve showed a linear correlation coefficient of 0.99932. There was no cross-reaction between ROBH and other commonly used anticoccidial drugs, which indicated that the monoclonal antibody had high specificity. The recoveries of ic-ELISA were in the range of 87.8% to 102.0%. The immunochromatographic strip assay displayed cut-off values of 10, 5 and 10 ng g-1 for shrimp, chicken breast and chicken liver samples, respectively. In addition, the results can be obtained within 10 min by naked eye observations. And in sample analysis, the results of ic-ELISA and the immunochromatographic strip assay were in accordance with those of LC-MS/MS. Thus, the ic-ELISA and immunochromatographic strip assay are effective methods for the detection of ROBH in shrimp, chicken breast and chicken liver samples.

Determination of robenidine in shrimp and chicken samples using the indirect competitive enzyme-linked immunosorbent assay and immunochromatographic strip assay.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201870007

Biomimetic Nanocomposites: Water‐Rich Biomimetic Composites with Abiotic Self‐Organizing Nanofiber Network (Adv. Mater. 1/2018)

A rapid, sensitive, specific and simple method based on Fluorescence Polarization Immunoassay (FPIA) was developed for the quantitative detection of Bisphenol A in water. 4, 4-Bis (4-hydroxyphenyl) valeric acid (BHPVA) was selected as the hapten to produce the immunogen. Fluorescein-labeled Bisphenol A derivatives (tracers) with different structures were synthesized and purified by thin layer chromatography. Based on the polyclonal antibody and tracers, an optimized FPIA method was developed with a detection limit (10% inhibition) of 2 μg L(-1) and a linear working range of 20 to 800 μg L(-1). FPIA was suitable for screening a large number of samples. The recoveries of fortified Tai lake water samples ranged from 91.85 to 102.78%, and tap water samples ranged from 90.36 to 96.01%. The coefficients of variation were all less than 20%. This FPIA method, which did not require a complicated cleanup process, proved to be very useful for the screening of Bisphenol A in environmental water samples.

A Simple, Sensitive, Rapid and Specific Detection Method for Bisphenol A based on Fluorescence Polarization Immunoassay

Salbutamol (SAL) is a short-acting β2-adrenergic receptor agonist (β-agonist) forbidden in livestock production. To develop a more sensitive and specific detection method for SAL, a new hapten was synthesized, keeping the structure of benzene ring side of SAL while changing the tert-butyl group structure that SAL shares with other β-agonists. Ten mice were immunized with a SAL hapten–keyhole limpet hemocyanin (KLH) conjugate, and cells were selected within a urine sample at the cell fusion stage. The best monoclonal antibody (Mab) had an IC50 value of 0.31 ng mL−1 in PBST buffer and an IC50 value of 0.19 ng mL−1 in a swine urine sample diluted five times (with a lower B0 value), and had no cross-reactivity with clenbuterol and other β-agonists. These results show that the hapten design was successful and that the Mab can potentially be used in highly sensitive immunoassays for specifically monitoring the illegal use of SAL in real samples.

Structure-specific hapten design for the screening of highly sensitive and specific monoclonal antibody to salbutamol

In this study, a highly sensitive monoclonal antibody (McAb) against chloramphenicol (CAP) was successfully raised and characterised by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Three antigens coupled with different proteins were synthesised and determined by the UV-vis method. After five rounds of immunisation, antisera were collected from six Balb/C mice and screened by ic-ELISA. The standard inhibition curve of one CAP McAb (labelled 6F11) showed the best sensitivity to CAP after optimisation of the principal working conditions. The half-maximal inhibition concentration (IC50) was calculated to be 0.01 ng/mL and the linear working range was from 0.0028 ng/mL to 0.040 ng/mL with a correlation coefficient of 0.996. This McAb showed high specificity, with negligible cross-reactivities detected towards CAP analogues (florfinicol, florfinicol amine, thiamphenicol). The recovery rate was 98.9–106.8% while the coefficient of variation was 4.45–6.05%. The IC50 value and other parameter...

Chuanlai Xu

Papers

Determination of robenidine in shrimp and chicken samples using the indirect competitive enzyme-linked immunosorbent assay and immunochromatographic strip assay.

Biomimetic Nanocomposites: Water‐Rich Biomimetic Composites with Abiotic Self‐Organizing Nanofiber Network (Adv. Mater. 1/2018)

A Simple, Sensitive, Rapid and Specific Detection Method for Bisphenol A based on Fluorescence Polarization Immunoassay

Structure-specific hapten design for the screening of highly sensitive and specific monoclonal antibody to salbutamol

Development and characterisation of an ultrasensitive monoclonal antibody for chloramphenicol