区块链产业发展:经济特性与中美路径差异

区块链具有去中心化、可追溯性两大核心特征和不可篡改、去信任化、信息透明、可匿名性四大衍生特征,并进一步引致出能够作用于经济领域的五大经济特性:减少信息不对称、降低组织的集中度、提供可置信的承诺、生成新的价值标的、减少交易成本。区块链是否能与产业良好融合是其能否有效发挥上述重要经济特性的一个重要因素。本文通过对中美区块链行业的对比分析发现,中国对于区块链的应用领域态度更为审慎,同时也具有更强的政策导向,主要应用领域为实体经济;而美国虽然对区块链的政策导向不如中国明显,但其在技术、人才培养等方面都具有显著优势,区块链应用规模在全球范围内处于绝对领先地位。总的来看,中国区块链产业发展面临审慎的金融政策与区块链特征不匹配、结合区块链与实体经济的配套设施相对缺失、区块链适用领域有待细化、区块链技术有待提升等问题。为进一步推动中国区块链产业发展,需要推动央行数字货币发展、加强数字化基础设施建设、针对性推动区块链行业发展、加强区块链技术基础研究。

Outcomes of palliative local treatment in metastatic colorectal cancer patients receiving chemotherapy plus bevacizumab

Objective The aim of this study was to assess the value of palliative local treatment of incurable metastatic lesions in colorectal cancer(CRC) patients receiving chemotherapy plus bevacizumab.Methods Data of 105 patients with histologically confirmed synchronous or metachronous metastatic CRC who received bevacizumab treatment from January 1, 2011 to January 31, 2017 were retrospectively reviewed. Sixteen(15%) patients who were treated with bevacizumab for less than 4 cycles were excluded, and finally, 89(85%) patients were enrolled. Among them, 33(37%) patients who received palliative local treatment were categorized into the palliative local treatment group, and the remaining 56(63%) patients were categorized into the chemotherapy plus bevacizumab group. The primary endpoint was overall survival(OS), which was calculated using Kaplan-Meier survival analyses. Factors possibly influencing survival were evaluated by univariate and multivariate analyses. Adverse events(AEs) were graded according to Common Terminology Criteria for Adverse Events, version 4.0. Grades 1–2 and 3–4 AEs of the two groups were compared and analyzed using the Fisher's exact test and χ~2 analysis.Results The median follow-up period was 20.4 months, ranging from 1 to 60 months. The median OS in the palliative local treatment group was 36.3 months(95% CI, 33.5–39.2), and that in the chemotherapy plus bevacizumab group was 20.5 months(95% CI, 17.6–23.4). Both the univariate(HR 0.13, 95% CI, 0.05–0.30, P < 0.001) and multivariate(HR 0.16, 95% CI, 0.07–0.39, P < 0.001) analyses showed that the addition of palliative local treatment could prolong survival compared with chemotherapy plus bevacizumab alone. There were no significant differences in the rates of common chemotherapy-or bevacizumab-related AEs between the two groups.Conclusion These findings suggest palliative local treatment is an effective and safe method for treating patients with incurable metastatic CRC receiving chemotherapy plus bevacizumab.

A ZnO thin-film driven microcantilever for nanoscale actuation and sensing

Zinc oxide(ZnO)thin film as a piezoelectric material for microelectromechanical system(MEMS)actuators and sensors was evaluated.ZnO thin films were deposited using radio frequency(RF)magnetron sputtering.Process parameters such as gas ratio,working pressure,and RF power were optimized for crystalline structure.The ZnO thin films were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).Good quality of ZnO thin films was further confirmed by a high transverse piezoelectric coefficient d31.A microcantilever was then designed,fabricated,and characterized.Design formulas of resonant frequency,actuation,and sensing sensitivities were derived.The resonant frequency was determined by an impedance analyzer.Tip deflection on nanometer level was demonstrated with the cantilever used as an actuator.The actuation sensitivity was found to be 12.2 nm/V.As a sensor,the cantilever was calibrated against a reference accelerometer.The sensing sensitivity was characterized to be 46 mV/g.The characterization results were compared with design specifications.The differences were caused mainly by thickness control in etching.This study showed that ZnO is a promising piezoelectric material for MEMS actuators and sensors in terms of excellent process compatibility and good piezoelectric performance.