On a Multi-criterion Problem of Planning Maritime Cargo Transportation

In this work, we consider a specific problem of optimal planning of maritime transportation of multiproduct cargo by ships of one （so-called ＂corporate strategy＂） or several （so-called ＂partially corporate strategy＂） companies： the core of the problem consists of the existence of the network of intermediate seaports （i.e., transitional seaports）, where for every ship arrived the cargo handling is done, and which are situated between the starting and the finishing seaports. In this work, there are mathematical models built from scratch in the form of multi-criterion optimization problem; according to the properties of the criteria and structure of the feasible solution set; are formulated different optimality conditions; are analysed different approaches for finding effective solutions （i.e., Pareto optimal solutions） and for check of the given solutions＇ effectiveness. In addition, in this work, there is considered and analysed well-known method of contraction of the Pareto boundary （goal attainment method of Gembicki）, then, it is used for reducing the built models to a one-criterion problem of linear programming.

Enzyme-driven Nanorobots Walking Along Predesigned Tracks on the DNA Origami for Cargo Transport and Catalysis

In molecular engineering,designing and synthesizing molecular machines with capable of performing complex tasks,remains a formidable challenge.DNA is an excellent candidate for building molecular robots because it is highly programmable.Here,we present an artificial nanorobot,in which a DNA cube serves as the inert‘body’,and nucleic acid catalysts based on an enzymatic nicking reaction act as the‘legs’for walking.The nanorobot can execute a series of actions,such as‘start’,‘turn’,and‘stop’when it walks along a predefined track.Its performance could be confirmed and monitored by using an atomic force microscope(AFM)and fluorescence spectroscopy.Inspired by biological machines,we artificially designed a series of specialized tasks that combined walking with control of cargo transport and catalysis.Real-time fluorescence kinetics curves provide monitoring signals for cargo transport and catalytic processes.Our work can enrich the toolbox of DNA machinery and has great potential for engineering molecular nanofactories.

A fine-grained perspective on the robustness of global cargo ship transportation networks

The robustness of cargo ship transportation networks is essential to the stability of the world trade system. The current research mainly focuses on the coarse-grained, holistic cargo ship transportation network while ignoring the structural diversity of different sub-networks. In this paper, we evaluate the robustness of the global cargo ship transportation network based on the most recent Automatic Identification System（AIS） data available. First, we subdivide three typical cargo ship transportation networks（i.e., oil tanker, container ship and bulk carrier） from the original cargo ship transportation network. Then, we design statistical indices based on complex network theory and employ four attack strategies, including random attack and three intentional attacks（i.e., degree-based attack, betweenness-based attack and flux-based attack） to evaluate the robustness of the three typical cargo ship transportation networks. Finally, we compare the integrity of the remaining ports of the network when a small proportion of ports lose their function. The results show that 1） compared with the holistic cargo ship transportation network, the fine-grain-based cargo ship transportation networks can fully reflect the pattern and process of global cargo transportation; 2） different cargo ship networks behave heterogeneously in terms of their robustness, with the container network being the weakest and the bulk carrier network being the strongest; and 3） small-scale intentional attacks may have significant influence on the integrity of the container network but a minor impact on the bulk carrier and oil tanker transportation networks. These conclusions can help improve the decision support capabilities in maritime transportation planning and emergency response and facilitate the establishment of a more reliable maritime transportation system.Abstract： The robustness of cargo ship transportation networks is essential to the stability of the world trade system. The current research mainly focuses on the coarse-grained, holistic cargo ship transportation network while ignoring the structural diversity of different sub-networks. In this paper, we evaluate the robustness of the global cargo ship transporta- tion network based on the most recent Automatic Identification System （AIS） data available. First, we subdivide three typical cargo ship transportation networks （i.e., oil tanker, container ship and bulk carrier） from the original cargo ship transportation network. Then, we design statistical indices based on complex network theory and employ four attack strategies, in- cluding random attack and three intentional attacks （i.e., degree-based attack, between- ness-based attack and flux-based attack） to evaluate the robustness of the three typical cargo ship transportation networks. Finally, we compare the integrity of the remaining ports of the network when a small proportion of ports lose their function. The results show that 1） com- pared with the holistic cargo ship transportation network, the fine-grain-based cargo ship transportation networks can fully reflect the pattern and process of global cargo transportation 2） different cargo ship networks behave heterogeneously in terms of their robustness, with the container network being the weakest and the bulk carrier network being the strongest; and 3） small-scale intentional attacks may have significant influence on the integrity of the con- tainer network but a minor impact on the bulk carrier and oil tanker transportation networks.These conclusions can help improve the decision support capabilities in maritime transportation planning and emergency response and facilitate the establishment of a more reliable maritime transportation system.

Unique features of myosin VI:a structural view

Myosin VI is the only known molecular motor for the transportation of cargo vesicles from the plus end to the minus end of actin filaments.Thus,myosin VI possesses several unique features to distinguish it from other myosin family motors,such as the ability to move in a reverse direction,the unusual large walking step size,and the cargo-mediated dimerization.Recent structural studies of myosin VI have provided mechanistic insights into these unique features.On the basis of the resolved structures of myosin VI each domains(i.e.,the structures of the Nterminal motor domain,the C-terminal cargo binding domain,and the region in the middle),the unique features of myosin VI will be reviewed here from a structural perspective.The structural studies of myosin VI definitely provide some answers about the unique features of myosin VI,but also raise significant questions on how myosin VI functions as a special motor both for directional cargo transport and for structural anchoring.

NUMBERS

24.59 mln units Auto sales in China last year,a year-on-year increase of 4.7 percent $87.43 mln Worth of cargo transported by cargo trains between Europe and Harbin,capital of northwest China’s Heilongjiang Province,since the service’s inception in June 2015