面向数据权利、数据定价和隐私计算的数据驱动学习

近年来,数据已成为数字经济中最重要的生产要素之一。与传统生产要素不同,数据的数字化性质使其难以合同和交易。因此,建立一个高效和标准的数据交易市场体系将有利于降低成本,提高行业各方的生产力。尽管许多研究致力于数据法规和其他数据交易问题,如隐私和定价,但很少有工作对机器学习和数据科学领域的这些研究进行全面回顾。为了提供对这个主题的完整和最新的理解,本文涵盖了数据交易过程中的三个关键问题:数据权利、数据定价和隐私计算。通过厘清这些主题之间的关系,本文提供了一个数据生态系统的全貌,其中数据由个人、研究机构和政府等数据主体生成,而数据处理者出于创新或运营目的获取数据,并通过适当的定价机制根据数据主体各自的所有权分配收益。为了使人工智能(AI)能够长期有益于人类社会的发展,人工智能算法需要通过数据保护法规(即隐私保护法规)进行评估,以帮助构建日常生活中值得信赖的人工智能系统。

An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps

There is a consensus in the aerospace field that the development of reusable liquid rockets can effectively reduce the launch expense.The pursuit of a long service life and reutilization highly depends on the bearing components.However,the rolling element bearings(REBs)used in the existing rocket turbopumps present obvious and increasing limitations due to their mechanical contacting mode.For REBs,high rotational speed and long service life are two performance indexes that mutually restrict each other.To go beyond the DN value(the product of the bearing bore and rotational speed)limit of REBs,the major space powers have conducted substantial explorations on the use of new types of bearings to replace the REB.This review discusses,first,the crucial role of bearings in rocket turbopumps and the related structural improvements of REBs.Then,with the prospect of application to the next generation of reusable liquid rocket turbopumps,the bearing candidates investigated by major space powers are summarized comprehensively.These promising alternatives to REBs include fluid-film,foil,and magnetic bearings,together with the novel superconducting compound bearings recently proposed by our team.Our more than ten years of relevant research on fluid-film and magnetic bearings are also introduced.This review is meaningful for the development of long-life and highly reliable bearings to be used in future reusable rocket turbopumps.

Role of temperature in tribolayers in fretting wear ofγ-TiAl alloy

The formation of tribolayers may play significant influences on fretting wear.At elevated temperature,the adhesion among wear debris and the increased diffusion rate facilitate the formation of tribolayers.However,the intensification of oxidation at elevated temperature and the low diffusion rate in oxides may play an adverse role.The present study aims to investigate the role of temperature in tribolayers in fretting wear using aγ-TiAl alloy.Scanning electron microscope,energy dispersive spectrometer,Raman spectrometer,transmission electron microscope and nanoindentation were utilized to investigate the wear debris,tribolayers,and wear scars.The fretting tests showed that,compared with that at room temperature(RT)and 350℃,significant reduction in wear rate and decrease in the fluctuation of friction coefficient occurred at 550 and 750℃.It was further revealed that when temperature raised from room temperature(RT)to 750℃,the oxidation of the wear debris increased slightly and the diffusion coefficients increased prominently,which facilities the formation of well tribo-sintered tribolayers.The well tribo-sintered tribolayers presented homogenous structure,nanocrystalline grains with excellent mechanical properties,and resulted in the improvement in the fretting wear resistance of theγ-TiAl alloy at 550 and 750℃.

Nonlinear dynamic analysis of low viscosity fluid-lubricated tilting-pad journal bearing for different design parameters

To reveal nonlinear dynamic rules of low viscosity fluid-lubricated tilting-pad journal bearings(TPJBs),the effects of design parameters on journal center orbits and dynamic minimum film thicknesses of water-lubricated TPJBs with and without static loads are investigated.The hydrodynamic bearing force used in the nonlinear dynamic analysis is an approximate analytical solution including the turbulence effect.The results reveal the methods for vibration suppression and load capacity improvement and give an optimal pivot offset and clearance ratio that can maximize the minimum film thickness.The results also show that four-pad TPJBs with loads between pads are preferred due to good dynamic performance and load capacity.This study would provide some guidance for nonlinear design of low viscosity fluid-lubricated TPJBs under dynamic loads.

Oridonin and its derivatives for cancer treatment and vercoming therapeutic resistance

Cancer is one of the diseases with high morbidity and mortality on a global scale.Chemotherapy remains the primary treatment option for most cancer patients,including patients with progressive,metastatic,and recurrent diseases.To date,hundreds of chemotherapy drugs are used to treat various cancers,however,the anti-cancer eficacy and outcomes are largely hampered by chemotherapy-associated toxicity and acquired therapeutic resistance.The natural product(NP)oridonin has been extensively studied for its anti-cancer efficacy.More recently,oridonin has been shown to overcome drug resistance through multiple mechanisms,with yet-to-be-defined bona fide targets.Hundreds of oridonin derivative analogs(oridonalogs)have been synthesized and screened for improved potency,bioavailability,and other drug properties.Particularly,many of these oridonalogs have been tested against oridonin for tumor growth inhibition,potential for overcoming therapeutic resistance,and immunity modulation.This concise review seeks to summarize the advances in this field in light of identifying clinical-trial level drug candidates with the promise for treating progressive cancers and reversing chemoresistance.

In vitro and in vivo characterization of erythrosin B and derivatives against Zika virus

Zika virus(ZIKV)causes significant human diseases without specific therapy.Previously we found erythrosin B,an FDA-approved food additive,inhibited viral NS2B−NS3 interactions,leading to inhibition of ZIKV infection in cell culture.In this study,we performed pharmacokinetic and in vivo studies to demonstrate the efficacy of erythrosin B against ZIKV in 3D mini-brain organoid and mouse models.Our results showed that erythrosin B is very effective in abolishing ZIKV replication in the 3D organoid model.Although pharmacokinetics studies indicated that erythrosin B had a low absorption profile,mice challenged by a lethal dose of ZIKV showed a significantly improved survival rate upon oral administration of erythrosin B,compared to vehicle control.Limited structure−activity relationship studies indicated that most analogs of erythrosin B with modifications on the xanthene ring led to loss or reduction of inhibitory activities towards viral NS2B−NS3 interactions,protease activity and antiviral efficacy.In contrast,introducing chlorine substitutions on the isobenzofuran ring led to slightly increased activities,suggesting that the isobenzofuran ring is well tolerated for modifications.Cytotoxicity studies indicated that all derivatives are nontoxic to human cells.Overall,our studies demonstrated erythrosin B is an effective antiviral against ZIKV both in vitro and in vivo.