Single Molecule Michaelis-Menten Equation beyond Quasi-Static Disorder

The classic Michaelis-Menten equation describes the catalytic activities for ensembles of enzyme molecules very well. But recent single-molecule experiment showed that the waiting time distribution and other properties of single enzyme molecule are not consistent with the prediction based on the viewpoint of ensemble. It has been contributed to the slow inner conformational changes of single enzyme in the catalytic processes. In this work we study the general dynamics of single enzyme in the presence of dynamic disorder. We find that at two limiting cases, the slow reaction and nondiffusion limits, Michaelis-Menten equation exactly holds although the waiting time distribution has a multiexponential decay behaviors in the nondiffusion limit.Particularly, the classic Michaelis-Menten equation still is an excellent approximation other than the two limits.Comment: 10 pages, 1 figur

Research progress of tumor-associated macrophages in immune microenvironment and targeted therapy of osteosarcoma

Osteosarcoma (OS) is a common primary malignant bone tumor in children and adolescents. The high recurrence and metastasis rate have become a common clinical problem to be solved, but there is no effective treatment. In recent years, studies have suggested that targeting the tumor microenvironment will likely become a new treatment direction for OS. Immune cell infiltration in the tumor microenvironment can promote tumor inflammation and angiogenesis. Tumor-associated macrophages (TAMs) are the most important immune cells in the tumor microenvironment, which play important roles in the development and metastasis of OS. The article reviews the effect of TAMs polarization on tumor cells and describes the effect of TAMs on the occurrence and development of OS from five aspects, including TAMs affecting the growth, invasion and metastasis, mediating chemotherapy resistance, stem cell-like phenotype, and immunosuppression of OS. The review summarizes the research progress of targeting TAMs in the treatment of OS in the past years, including influencing the recruitment of TAMs, promoting the polarization of M2 type to M1 type, targeting CD47 to promote the phagocytosis of TAMs, and targeting the immune checkpoint of TAMs, aiming to provide new directions and ideas for targeted therapy of OS

A Research on the Control System of High-Speed Homopolar Motor with Solid Rotor Based on Flywheel Energy Storage

In view of the defects of the motors used for flywheel energy storage such as great iron loss in rotation, poor rotor strength, and robustness, a new type of motor called electrically excited homopolar motor is adopted in this paper for flywheel energy storage. Compared to general motors, this motor has the advantages of simple structure, high rotor strength, and low iron loss in rotation. A double closed-loop PI governing system of the new motor was designed, modeled, and simulated with this motor as the controlled object on simulation platform. The simulation result shows that the PI-controlled electrically excited homopolar motor system realized fast speed governing and good system performance, achieved the purpose of quick charge by flywheel energy storage, verified the correctness and effectiveness of the design scheme, and provided data reference and theoretical basis for the practice of future flywheel energy storage experiments

Fluorescence Enhanced Optical Resonator Constituted of Quantum Dots and Thin Film Resonant Cavity for High-Efficiency Reflective Color Filter

Conventional color filters selectively absorb a part of the backlight while reflecting or transmitting other light, resulting in the problem of low efficiency and energy wasting. For this problem, a new concept of fluorescence enhanced optical resonator was proposed and verified in this paper. The new structure consists of structural color filter and light-conversion material. Specially, a thin film resonant cavity was designed, and InP/ZnSe/ZnS quantum dots were inserted inside the resonator. When illuminated by sunlight, the novel fluorescence enhanced optical resonator could not only reflect the specific light, but also convert absorbed energy into desired light, leading to the utilization efficiency improvement of solar energy. An all-dielectric red fluorescence enhanced optical resonator was fabricated, with peak equivalent reflectance up to 105%. Compared with a thin film resonator, the enhancement coefficient of the as-proposed structure is about 124%. The new optical structure can utilize solar source efficiently, showing application potential as the next generation of reflective color filters for display

Application of a tracing experiment in the prediction of water and mud inrush in the Wantan Tunnel

Taking the Wantan Tunnel of Yilai Highway as the study case, the average water inflow and the water inflow in the wet season of the tunnel are calculated through field investigation, groundwater tracer experiment, groundwater flow monitoring, and atmospheric rainfall infiltration method. Meanwhile, the realistic failure process analysis(RFPA) is used to analyze the possibility of tunnel water inrush is judged. The results of field survey and tracer test show that the karst pipeline of Wantan Tunnel is a multi-branched, mixed-type karst pipeline with complicated hydrogeological conditions. The water inflow in wet season is about 4.6 times of the average tunnel water inflow. Mud failure will go through the stages of crack initiation, crack expansion, further crack expansion, and through-through failure. At the same time, when the water flow at the karst pipeline reaches about 2.7 to 3.5 times the initial value (37 248 m3/d), water gushing and mud inrush damage will occur, that is, when the flow of water outlet 2 reaches 10 000 to 13 000 m3/d, There is a very high risk of water and mud gushing in the Wantan Tunnel

Shanghai Jiao-Tong University Shanghai, P.R.China

Weblogs have become a prevalent source of information for people to express themselves. In general, there are two genres of contents in weblogs. The first kind is about the webloggers’ personal feelings, thoughts or emotions. We call this kind of weblogs affective articles. The second kind of weblogs is about technologies and different kinds of informative news. In this paper, we present a machine learning method for classifying informative and affective articles among weblogs. We consider this problem as a binary classification problem. By using machine learning approaches, we achieve about 92 % on information retrieval performance measures including precision, recall and F1. We set up three studies on the applications of above classification approach in both research and industrial fields. The above classification approach is used to improve the performance of classification of emotions from weblog articles. We also develop an intent-driven weblog-search engine based on the classification techniques to improve the satisfaction of Web users. Finally, our approach is applied to search for weblogs with a great deal of informative articles

Femtosecond Laser Direct Writing of Optical Overpass

With the rapid increase in information density, problems such as signal crosstalk and crossover restrict the further expansion of chip integration levels and packaging density. Based on this, a novel waveguide structure—photonic jumper wire—is proposed here to break through the technical restrictions in waveguide crossing and parallel line wrapping, which hinder the integration of photonic chips. Furthermore, we fabricated the optical overpass to realize a more complex on-chip optical cross-connection. Our method and structure promote a series of practical schemes for improving optical chip integration

Energy Absorption and Failure Modes of Different Composite Open-Section Crush Elements under Axial Crushing Loading

In order to study the energy absorption characteristics of the open-section thin-walled composite structures with different cross-sections, axial compression tests were carried out at loading speeds of 0.01 m/s, 0.1 m/s, and 1 m/s. Finite element models were built to predict the crushing response and energy absorption behaviors of these open-section structures. The effects of the cross-section’s shape, cross-section aspect ratio, trigger mechanism, and loading speed on the energy absorption characteristics of the composite structures were analyzed. The results show that the average crushing loads of the hat-shaped and Ω-shaped open-section structures are 14.1% and 14.6% higher than those of C-shaped open-section structures, and the specific energy absorption (SEA) values are 14.3% and 14.8% higher than that of C-shaped open-section structures, respectively. For the C-shaped open-section structures, a 45° chamfer trigger is more effective in reducing the initial peak load, while a 15° steeple trigger is more appropriate for the hat-shaped open-section structures. The average crushing loads and SEA of C-shaped, hat-shaped, and Ω-shaped open-section structures are reduced when the loading speed is increased from 0.01 m/s to 1 m/s. The increase in loading speed leads to the splashing of debris and thus reduces the loading area and material utilization of open-section structures, leading to a decrease in energy absorption efficiency