A multifunctional ribonuclease A-conjugated carbon dot cluster nanosystem for synchronous cancer imaging and therapy

Carbon dots exhibit great potential in applications such as molecular imaging and in vivo molecular tracking. However, how to enhance fluorescence intensity of carbon dots has become a great challenge. Herein, we report for the first time a new strategy to synthesize fluorescent carbon dots (C-dots) with high quantum yields by using ribonuclease A (RNase A) as a biomolecular templating agent under microwave irradiation. The synthesized RNase A-conjugated carbon dots (RNase A@C-dots) exhibited quantum yields of 24.20%. The fluorescent color of the RNase A@C-dots can easily be adjusted by varying the microwave reaction time and microwave power. Moreover, the emission wavelength and intensity of RNase A@C-dots displayed a marked excitation wavelength-dependent character. As the excitation wavelength alters from 300 to 500 nm, the photoluminescence (PL) peak exhibits gradually redshifts from 450 to 550 nm, and the intensity reaches its maximum at an excitation wavelength of 380 nm. Its Stokes shift is about 80 nm. Notably, the PL intensity is gradually decreasing as the pH increases, almost linearly dependent, and it reaches the maximum at a pH = 2 condition; the emission peaks also show clearly a redshift, which may be caused by the high activity and perfective dispersion of RNase A in a lower pH solution. In high pH solution, RNase A tends to form RNase A warped carbon dot nanoclusters. Cell imaging confirmed that the RNase A@C-dots could enter into the cytoplasm through cell endocytosis. 3D confocal imaging and transmission electron microscopy observation confirmed partial RNase A@C-dots located inside the nucleus. MTT and real-time cell electronic sensing (RT-CES) analysis showed that the RNase A@C-dots could effectively inhibit the growth of MGC-803 cells. Intra-tumor injection test of RNase A@C-dots showed that RNase A@C-dots could be used for imaging in vivo gastric cancer cells. In conclusion, the as-prepared RNase A@C-dots are suitable for simultaneous therapy and in vivo fluorescence imaging of nude mice loaded with gastric cancer or other tumors.     

建筑钢结构高强钢不适合大线能量焊接

在建筑钢结构焊接工程中,钢材是焊接的第一对象,所有的焊接工艺必须从钢材的特性,尤其是焊接性岀发。因此,建筑钢结构焊接工程所采用的钢材是钢结构焊接工程的第一质量要素。针对目前建筑钢结构高强钢焊接技术准备不足的现状,阐述了建筑钢结构高强钢不适合大线能量焊接的道理。从高强钢的基础知识到高强钢焊接技术的具体讨论进行了详细的论证。目的在于引起设计、施工焊接从业人员的注意和思考,迅速调整思路,进入到符合客观规律的正轨,从而保证工程质量和进度。     

TRIZ创新方法剖析路面渗水仪底座和路面的密封性能

针对路面渗水仪底座和路面的密封性能不良问题，运用TRIZ创新方法的因果链、技术矛盾、物理矛盾、进化分析等工具找到原因，获得解决方案。通过调研及试用，不断优化及调整所选方案，达到最优解决效果。应用效果证明TRIZ理论有助于创新并快速解决工程实际问题。     

CO2 sequestration in depleted methane hydrate deposits with excess water

The recent increase in atmospheric CO₂ concentration makes it necessary to investigate new ways to reduce CO₂ emissions. Simultaneously, natural gas hydrate mining technology is developing rapidly. The use of depleted methane hydrate (MH) deposits as potential sites for CO₂ storage is relatively safe and economical. This method can alleviate the shortage of hydrate displacement gas with CO₂. The purpose of this study was to investigate CO₂ hydrate formation characteristics during the seepage process—in reservoirs with excess water—and their effect on CO₂ storage. The experimental process can be divided into 5 parts: MH formation, water injection, MH dissociation, CO₂ hydrate formation, and CO₂ hydrate dissociation. Magnetic resonance imaging was employed to monitor the distribution of liquid water, and the effects of different parameters on the formation and dissociation of CO₂ hydrates were analyzed. It was found that a state of initial water saturation can effectively control hydrate saturation in artificial MH reservoirs for hydrate reservoirs with excess gas. In the process of CO₂ flow, initial water saturation was not the main controlling factor for CO₂ hydrate formation. Increasing the flow pressure and reducing the flow rate were beneficial for CO₂ hydrate formation. This study is of great significance for advancing the science of CO₂ geological storage in the form of deep‐sea hydrates.     

Multi-objective two-sided mixed-model assembly line balancing using particle swarm optimisation with negative knowledge

Particle swarm optimisation (PSO) is an evolutionary metaheuristic inspired by the swarming behaviour observed in flocks of birds. The applications of PSO to solve multi-objective discrete optimisation problems are not widespread. This paper presents a PSO algorithm with negative knowledge (PSONK) to solve multi-objective two-sided mixed-model assembly line balancing problems. Instead of modelling the positions of particles in an absolute manner as in traditional PSO, PSONK employs the knowledge of the relative positions of different particles in generating new solutions. The knowledge of the poor solutions is also utilised to avoid the pairs of adjacent tasks appearing in the poor solutions from being selected as part of new solution strings in the next generation. Much of the effective concept of Pareto optimality is exercised to allow the conflicting objectives to be optimised simultaneously. Experimental results clearly show that PSONK is a competitive and promising algorithm. In addition, when a local search scheme (2-Opt) is embedded into PSONK (called M-PSONK), improved Pareto frontiers (compared to those of PSONK) are attained, but longer computation times are required.     

Actuator line/Navier–Stokes computations for the MEXICO rotor: comparison with detailed measurements

In the European collaborative MEXICO (Model Experiments in Controlled Conditions) project, a series of experiments was carried out on a 4.5 m diameter wind turbine rotor to validate numerical diagnostics tools. Here, some of the measured data are compared with computations of the combined actuator line/Navier–Stokes (AL/NS) model developed at the Technical University of Denmark. The AL/NS model was combined with a large eddy simulation technique and used to compute the flow past the MEXICO rotor in free air and in the DNW German‐Dutch wind tunnel for three commonly defined test cases at wind speeds of 10, 15 and 24 m s ^?1. Two sets of airfoil data were used. Comparisons of blade loadings showed that the AL/NS technique with the modified airfoil data is in better agreement with the measurements than with the original 2D airfoil data. Comparisons of detailed near‐wake velocities showed good agreement with the measurements. Computations including the influence of the geometry of the wind tunnel showed that tunnel effects are not significant and the effect of the geometry of the wind tunnel only results in a speedup of 3% at a thrust coefficient of C_T = 1.Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of ozone treatment on aflatoxin B1 and safety evaluation of ozonized corn

This paper studies the ozone treatment effect on degradation of aflatoxin B₁ (AFB₁) in corn with different moisture content (MC). The toxicity of the degradation products (DPs) of the ozone-treated AFB₁-Contaminated Corn (ACC) was also evaluated using the human hepatocellular carcinoma cell line (HepG2) as model cells. The degradation rate of AFB₁ in corn increases with ozone concentration and treatment time. The results showed that ACC with 13.47% MC was easier to be degraded by ozone than with 20.37% MC. Treated with 90 mg L⁻¹ ozone for 20 min and 40 min, AFB₁ in corn with 13.47% MC decreased from 83 μg kg⁻¹ to 18.12 μg kg⁻¹ and 9.9 μg kg⁻¹, respectively, well meeting the China National Standard of AFB₁ in corn (20 μg kg⁻¹). In order to evaluate the safety of ozone used on ACC, the impacts of AFB₁ as well as untreated and ozone-treated ACC with the same level of AFB₁ content on HepG2's survival rate, morphology, and apoptosis were studied. The results showed that ACC had high cell toxicity while the toxicity of ozone-treated ACC had no significant difference with that of the AFB₁-free culture solution. It is concluded that ozonation can quickly and effectively degrade AFB₁ in corn and diminish ACC's toxicity, and therefore, ozonation is expected to be an effective, fast, and safe method for AFB₁ degradation in ACC.     

PF线C型钩载荷梁优化设计

针对高线厂PF线C形钩载荷梁存在的结构缺陷，对载荷梁上吊轴的安装结构进行了改进，使之能够防尘，并减小转动摩擦阻力，减少了PF线设备故障，降低了备件消耗和系统能耗。     

浅谈上跨营业线双机联合起升架梁施工技术

本文按照双机联合起升架梁施工工艺流程进行了论述，使读者能够清晰掌握现场施工程序。并结合工程实际，提出了相关优化措施，希望对于指导今后类似工程施工能够起到一定借鉴作用，并能为相关工作者提供参考。