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

This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.

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The electronic properties of graphene

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

Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

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Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

Graphene is a wonder material with many superlatives to its name. It is the thinnest known material in the universe and the strongest ever measured. Its charge carriers exhibit giant intrinsic mobility, have zero effective mass, and can travel for micrometers without scattering at room temperature. Graphene can sustain current densities six orders of magnitude higher than that of copper, shows record thermal conductivity and stiffness, is impermeable to gases, and reconciles such conflicting qualities as brittleness and ductility. Electron transport in graphene is described by a Dirac-like equation, which allows the investigation of relativistic quantum phenomena in a benchtop experiment. This review analyzes recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.

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Graphene: Status and Prospects

The properties of suspended graphene are currently attracting enormous interest, but the small size of available samples and the difficulties in making them severely restrict the number of experimental techniques that can be used to study the optical, mechanical, electronic, thermal and other characteristics of this one-atom-thick material. Here we describe a new and highly-reliable approach for making graphene membranes of a macroscopic size (currently up to 100 microns in diameter) and their characterization by transmission electron microscopy. In particular, we have found that long graphene beams supported by one side only do not scroll or fold, in striking contrast to the current perception of graphene as a supple thin fabric, but demonstrate sufficient stiffness to support extremely large loads, millions of times exceeding their own weight, in agreement with the presented theory. Our work opens many avenues for studying suspended graphene and using it in various micromechanical systems and electron microscopy.

Macroscopic graphene membranes and their extraordinary stiffness

The development of an incisional hernia is a common complication of midline laparotomy. Improper fascial closure techniques have a significant role in its development. It can also lead to poor wound healing and increase the risk of developing surgical site infections (SSI). Upon conducting a thorough literature review, various studies have been conducted on closing abdominal wounds. However, there is a dearth of studies portraying the role of suture length in the prevention of incisional hernia and SSI. The effect of using a greater suture-to-wound length ratio on postoperative outcomes was not clearly analyzed or described. The objective of this study is to assess the effectiveness of using a suture length to wound length ratio ≥4:1 versus a ratio <4:1 in preventing postoperative complications such as incisional hernia and SSI. This study is a systematic review of randomized controlled trials on abdominal wound closure using a suture length to wound length ratio of ≥4:1 and <4:1. published in PubMed, Google Scholar, and Cochrane library. The inclusion and exclusion criteria were defined. The relevant studies identified from 1991 to 2017, were included in the analysis. The primary endpoint was the incidence of incisional hernia, and the secondary outcome was the incidence of SSI. This meta-analysis considered five randomized controlled trials that compared the effects of using different suture length to wound length ratios during abdominal closure on incisional hernia and SSI. Participants ranged in size from 100 to 363. The trial follow-up period ranged from a minimum of 10 months to five years. The outcomes studied in the two groups were incisional hernia and SSI. The relative risk of the occurrence of incisional hernia if the suture length to wound length ratio was ≥4:1 was 0.42 with a p-value of <0.001 which was considered significant. This implied that using a suture length of more than four times that of the wound i.e., 4:1, significantly decreases the risk of developing an incisional hernia by more than half. The relative risk of developing a SSI was 0.98 with a p-value of 0.966. Thus, this method of abdominal closure uing a longer suture length to wound length ratio does not contribute to an increased incidence or significant change in the risk of developing SSI.

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Effect of Suture Length on the Incidence of Incisional Hernia and Surgical Site Infection in Patients Undergoing Midline Laparotomy: A Systematic Review and Meta-Analysis

In this letter we use graphene bubbles to study the Raman spectrum of graphene under biaxial (e.g. isotropic) strain. Our Gruneisen parameters are in excellent agreement with the theoretical values. Discrepancy in the previously reported values is attributed to the interaction of graphene with the substrate. Bilayer balloons (intentionally pressurized membranes) have been used to avoid the effect of the substrate and to study the dependence of strain on the inter-layer interactions.

Raman Spectroscopy of graphene and bilayer under biaxial strain: bubbles and balloons

Insect pest invasions cause significant damage to crop yields, and the resultant economic losses are truly alarming. Climate change and trade liberalization have opened new ways of pest invasions. Given the consumer preference towards organic agricultural products and environment-friendly nature of natural pest control strategies, biological control is considered to be one of the potential options for managing invasive insect pests. Drosophila suzukii (Drosophilidae) is an extremely damaging fruit pest, demanding development of effective and sustainable biological control strategies. In this study, we assessed the potential of the parasitoid Leptopilina japonica (Figitidae) as a biocontrol agent for D. suzukii using ecological niche modeling approaches. We developed global-scale models for both pest and parasitoid to identify four components necessary to derive a niche based, target oriented prioritization approach to plan biological control programs for D. suzukii: (i) potential distribution of pest D. suzukii, (ii) potential distribution of parasitoid L. japonica, (iii) the degree of overlap in potential distributions of pest and parasitoid, and (iv) biocontrol potential of this system for each country. Overlapping suitable areas of pest and parasitoid were identified at two different thresholds and at the most desirable threshold (E = 5%), potential for L. japonica mediated biocontrol management existed in 125 countries covering 1.87 × 107 km2, and at the maximum permitted threshold (E = 10%), land coverage was reduced to 1.44 × 107 km2 in 121 countries. Fly pest distributional information as a predictor variable was not found to be improving parasitoid model performance, and globally, only in half of the countries, >50% biocontrol coverage was estimated. We therefore suggest that niche specificities of both pest and parasitoid must be included in site-specific release planning of L. japonica for effective biocontrol management aimed at D. suzukii. This study can be extended to design cost-effective pre-assessment strategies for implementing any biological control management program.

Mapping the global distribution of invasive pest Drosophila suzukii and parasitoid Leptopilina japonica: implications for biological control

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Rahul R. Nair

Papers

Macroscopic graphene membranes and their extraordinary stiffness

Effect of Suture Length on the Incidence of Incisional Hernia and Surgical Site Infection in Patients Undergoing Midline Laparotomy: A Systematic Review and Meta-Analysis

Raman Spectroscopy of graphene and bilayer under biaxial strain: bubbles and balloons

Mapping the global distribution of invasive pest Drosophila suzukii and parasitoid Leptopilina japonica: implications for biological control

Metal and 2D Material Interaction Investigated via HAADF STEM