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.

/pdf/present-and-future-of-surface-enhanced-raman-scattering-34aqgcm385.pdf

Present and Future of Surface-Enhanced Raman Scattering

This chapter introduces the overview of eight kinds of food allergens containing the allergic reaction, classification, and characteristics. Then, the extraction methods of allergen protein and monoclonal antibody production were depicted in this chapter. Then, the enzyme-linked immunosorbent assay for each allergen which represents a kind of food allergens was established. Meanwhile, the colloidal gold immunochromatographic strip test for two kinds of allergen proteins was also depicted.

Immunoassay for Allergens in Food

The transmembrane receptor Kremen2 has been reported to participate in the tumorigenesis and metastasis of gastric cancer. However, the role of Kremen2 in non-small cell lung cancer (NSCLC) and the underlying mechanism remain unclear. This study aimed to explore the biological function and regulatory mechanism of Kremen2 in NSCLC.The correlation between Kremen2 expression and NSCLC was assessed by analyzing the public database and clinical tissue samples. Colony formation and EdU assays were performed to examine cell proliferation. Transwell and wound healing assays were used to observe cell migration ability. Tumor-bearing nude mice and metastatic tumor models were used to detect the in vivo tumorigenic and metastatic abilities of the NSCLC cells. An immunohistochemical assay was used to detect the expression of proliferation-related proteins in tissues. Western blot, immunoprecipitation and immunofluorescence were conducted to elucidate the Kremen2 regulatory mechanisms in NSCLC.Kremen2 was highly expressed in tumor tissues from NSCLC patients and was positively correlated with a poor patient prognosis. Knockout or knockdown of Kremen2 inhibited cell proliferation and migration ability of NSCLC cells. In vivo knockdown of Kremen2 inhibited the tumorigenicity and number of metastatic nodules of NSCLC cells in nude mice. Mechanistically, Kremen2 interacted with suppressor of cytokine signaling 3 (SOCS3) to maintain the epidermal growth factor receptor (EGFR) protein levels by preventing SOCS3-mediated ubiquitination and degradation of EGFR, which, in turn, promoted activation of the PI3K-AKT and JAK2-STAT3 signaling pathways.Our study identified Kremen2 as a candidate oncogene in NSCLC and may provide a potential target for NSCLC treatment. 

/pdf/kremen2-drives-the-progression-of-non-small-cell-lung-cancer-3nh7gpkt.pdf

Kremen2 drives the progression of non-small cell lung cancer by preventing SOCS3-mediated degradation of EGFR

This chapter introduces the overview of heavy metal classification, hazard, and the maximum residue levels in the food. Then, the design of haptens for producing heavy metal antibodies was compared in this chapter. The acquired antibodies targeted to different heavy metal have high specificity and sensitivity, which have been characterized by indirect enzyme-linked immunosorbent assay. Then, the pretreatment methods of different food samples were presented for the application of ELISA for detection of heavy metal. The colloidal gold immunochromatographic strips were also described with different detection ranges and cut-off values. Finally, the perspective of immnunoassays for heavy metal analysis was discussed. As an alternative tool for fast detection heavy metal on-site, there are still lack of effective pretreatment method. Therefore, developing a high-efficiency and simple extraction method is the key factor for heavy metal immunoassays.

Heavy Metal Immunoassay in Food

Spontaneous symmetry breaking of semiconductor nanorods and assemblies

Cannabidiol (CBD), the most predominant cannabinoid, may cause addiction and liver damage. In this study, we synthesized a CBD hapten containing the carboxyl group of the spacer arm by derivatizing CBD. A highly specific and sensitive monoclonal antibody (mAb) was prepared with a half-maximal inhibitory concentration of 2.03 ng mL-1 and a limit of detection of 0.32 ng mL-1. MAb was highly specific for CBD. We developed an immunochromatographic assay (ICA) for the detection of CBD in functional beverages with a visible limit of detection of 100 ng mL-1 and a cut-off of 1000 ng mL-1. Compared with HPLC, ICA is more efficient and accurate and can be used for the rapid on-site detection of CBD in samples.

Chuanlai Xu

Papers

Immunoassay for Allergens in Food

Kremen2 drives the progression of non-small cell lung cancer by preventing SOCS3-mediated degradation of EGFR

Heavy Metal Immunoassay in Food

Spontaneous symmetry breaking of semiconductor nanorods and assemblies

Development of a gold nanoparticle-based lateral-flow strip for the detection of cannabidiol in functional beverages.