Knowledge Graph Question Answering based on Contrastive Learning and Feature Transformation

Traditional Knowledge Graph Question Answering(KGQA) usually focuses on entity recognition and relation detection. Common relation detection methods cannot detect new relations without corresponding word entries in the system, and the propagation of errors leads to the loss of some semantic similarity information. In this paper, we propose an end-to-end knowledge graph question-answering framework (TransCL). Latent knowledge is first mined from the knowledge base and augmented information is generated in the form of question-answer pairs. Positive features are then transformed into difficult positive features using a feature transformation method based on positive extrapolation. We use contrastive learning methods to aggregate vectors and retain the original information, capturing deep matching features between data samples by contrast. TransCL is more capable of fuzzy matching and dealing with unknown inputs. Experiments show that our method achieves an F1 score of 85.50% on the NLPCC-ICCPOL-2016 open domain QA dataset

Joint Extraction of Biomedical Entities and Relations based on Decomposition and Recombination Strategy

Entities and relations extraction is one of the key task to build medical knowledge graph, which is of great significance to the development of medical artificial intelligence. However, overlapping triples are great challenge for biomedical entities and relations extraction. In order to improve the performance of biomedical entities and relations extraction, we propose a joint extraction of entities and relations method based on decomposition and recombination strategy to mine biomedical text. Our method decomposes entities and relations extraction task into three related sub-modules, which are entity tagging module, relation classification module and recombination matching module. Our main contributions are as follows: first, we introduce a decomposition and recombination end-to-end learning framework for joint entities and relations extraction. Second, we propose a bi-directional prediction method to deal with the overlapping triples problem. Finally, we propose the negative samples generation method to alleviate the error accumulation among these modules. The extensive experiments demonstrate that our method can improve the F1 score by 4.36%, 2.13% and 11.72% in ADE, DDI and BB biomedical corpus

Controlling Shareholders’ Stock Pledge and Choices of Management Earnings Forecasts Strategies：Empirical Evidence from China's Capital Markets

笔者感谢澳门科技大学张旭助理教授、重庆大学辛清泉教授、北京大学王立彦教授、厦 门大学曲晓辉教授与刘峰教授等专家在 2017 年 4 月于澳门科技大学举办的《当代会计评论》2017 春季学术研讨会上给予本 文的点评和宝贵的修改建议。【中文摘要】本文以我国 2004～2015 年沪深两市非金融类上市公司季度数据为样 本，系统考察了控股股东股权质押对管理层盈余预测策略选择的影响。研究发 现上市公司管理层在控股股东股权质押前，有强烈的动机发布“好消息”或“正 向偏差”的机会主义盈余预测。进一步研究表明，控股股东股权质押前的市场 表现越差，管理层发布机会主义盈余预测的动机越强；管理层配合控股股东股 权质押的机会主义盈余预测动机在质押前最强、质押期内次之、解押后最弱； 严格的外部监督有助于抑制管理层采用乐观的预测策略。本文的研究结论为市 场各方洞悉我国上市公司控股股东与管理层之间的合谋行为提供了新的经验证 据，也为投资者决策以及监管者制定相关政策提供了新的参考。 【Abstract】Using a sample of Chinese listed companies from 2004 to 2015 on the A-Share market of China，this paper empirically investigates the effect of controlling shareholders’ stock pledge on management earnings forecasts strategies. The results indicate that managers have strong incentives to report good news and positively biased forecasts prior to controlling shareholders’ stock pledge，especially in firms with poor pre-forecast market performance， while rigid regulatory policies and external supervision mechanisms can constrain managers’ ex ante opportunistic forecast strategies to some extent. The conclusions can not only provide a new and direct evidence for the collusion behavior of controlling shareholders and managers，but also can help people understand the interest conflict behind controlling shareholders’ stock pledge. Meanwhile，the results can provide references for investors to make investment decisions and for the market regulators to establish regulatory policies.本文是国家自然科学基金面上项目“控股股东股权质押动机、经济后果与治理机制研究” （71672157）的阶段性成果。本文感谢教育部人文社会科学重点研究基地重大项目“大数据环境下财务报告分析框架的重构 与应用”（15JJD630011）的资助

Label-Free Simultaneous Analysis of Fe(III) and Ascorbic Acid Using Fluorescence Switching of Ultrathin Graphitic Carbon Nitride Nanosheets

A simple chemical oxidation and ultrasound exfoliation method has been developed to synthesize the two-dimensional and ultrathin-layer materialsgraphitic carbon nitride nanosheets (g-C₃N₄ NNs). The prepared ultrathin g-C₃N₄ NNs display strong fluorescence and stability, including good photostability and excellent antisalt ability. Herein, a new “on–off–on” fluorescent switching sensor is designed. The iron ion (Fe³⁺) has an ultrasensitive response to quench the fluorescence of g-C₃N₄ NNs based on the synergistic effect between inner filter effect and photoinduced electron transfer. The linear limit for Fe³⁺ was from 0.05 to 30 μmol L^–1 with a detection limit of 0.018 μmol L^–1. Meanwhile, the fluorescence of g-C₃N₄ NNs can recover through the redox reaction between Fe³⁺ and ascorbic acid (AA). In addition, the linear range for AA was from 0.2 to 112.5 μmol L^–1 with a 0.086 μmol L^–1 detection limit. The proposed method exhibited rapid response, excellent selectivity, wide detection range, and low detection limit for simultaneous analysis of Fe³⁺ and AA, and it was applied for the determination of Fe³⁺ and AA in water sample and human serum with satisfactory results

Enhancement of osteogenesis using a novel porous hydroxyapatite scaffold in vivo and vitro

The repair of large maxillofacial bony defects using regular scaffolds is restricted by the osteogenic effect. It was postulated that a novel porous hydroxyapatite (HA) scaffolds with a 25-30 mu m groove structure (HAG) may counter this limitation. In this study we evaluated the biocompatibility of HAG scaffolds both in vitro and in vivo in beagle dogs by investigating the enhancement of scaffolds bioactivity and osteogenesis. Compared with a regular HA scaffolds, the HAG scaffolds significantly promoted human placenta-derived mesenchymal stem cell (hPMSC) osteogenic differentiation and the maturation of osteoblasts. This is achieved by increasing protein adsorption, as well as promoting directed growth and expression of osteogenic genes in vitro. The compressive strength of HAG scaffolds was significantly greater than HA in both dorsal muscle and the mandibular distraction area after in vivo implantation, with hematoxylin and eosin staining demonstrating new bone formation and vasculogenesis. Immunochemical staining and micro-CT scanning demonstrated increased expression of osteogenic factors (BMP2, OCN and COL-1) and bone density in the HAG scaffolds compared with HA. Based on the above results, we conclude that HAG scaffolds that have a groove structure induce greater osteogenesis and possess improved ostoegenesis which could be utilized in the clinical treatment

Identification and Quantitation of CC Location Isomers of Unsaturated Fatty Acids by Epoxidation Reaction and Tandem Mass Spectrometry

Unsaturated fatty acids (FAs) serve as nutrients, energy sources, and signaling molecules for organisms, which are the major components for a large variety of lipids. However, structural characterization and quantitation of unsaturated FAs by mass spectrometry remain an analytical challenge. Here, we report the coupling of epoxidation reaction of the CC in unsaturated FAs and tandem mass spectrometry (MS) for rapid and accurate identification and quantitation of CC isomers of FAs in a shotgun lipidomics approach. Epoxidation of the CC leads to the production of an epoxide which, upon collision induced dissociation (CID), produces abundant diagnostic ions indicative of the CC location. The total intensity of the same set of diagnostic ions for one specific FA CC isomer was also used for its relative and absolute quantitation. The simple experimental setup, rapid reaction kinetics (<2 min), high reaction yield (>90% for monounsaturated FAs), and easy-to-interpret tandem MS spectra enable a promising methodology particularly for the analysis of unsaturated FAs in complex biological samples such as human plasma and animal tissues