DARPA Robotics Grand Challenge Participation and Ski-Type Gait for Rough-Terrain Walking

In this paper, we briefly introduce the history of the Defense Advanced Research Projects Agency(DARPA) Grand Challenge programs with particular focus on the 2012 Robotics Challenge. As members of team DRC-HUBO, we propose different approaches for the Rough-Terrain task, such as enlarged foot pedals and a transformation into quadruped walking. We also introduce a new gait for humanoid robot locomotion to improve stability performance, called the Ski-Type gait. We analyze the stability performance of this gait and use the stability margin to choose between two candidate step sequences, Crawl-1 and Crawl-2. Next, we perform a force/torque analysis for the redundant closedchain system in the Ski-Type gait, and determine the joint torques by minimizing the total energy consumption. Based on the stability and force/torque analysis, we design a cane length to support a feasible and stable Crawl-2 gait on the HUBO2 humanoid robot platform. Finally, we compare our experimental results with biped walking to validate the SkiType gait. We also present our team performance in the trials of the Robotics Challenge.

PpINH1,an invertase inhibitor,interacts with vacuolar invertase PpVIN2 in regulating the chilling tolerance of peach fruit

Sucrose metabolism,particularly the decomposition of sucrose by invertase,plays a central role in plant responses to cold stress.Invertase inhibitors(INHs)evolved in higher plants as essential regulators of sucrose metabolism.By limiting invertase activity,INHs keep cellular sugar levels elevated,which provides enhanced protection to plants under stress.Our results showed that the expression of PpVIN2,the only vacuolar invertase(VIN)gene in peach fruit sensitive to chilling temperatures,increases significantly during cold storage,while VIN enzyme activity increases more modestly.We also found that peach fruit transiently overexpressing PpINH1 had decreased VIN activity.Interactions of PpINH1 and PpVIN2 with recombinant proteins were shown by yeast two-hybrid assays and bimolecular fluorescence complementation assays,as well as in vitro.During cold storage,trehalose-treated peach fruit had significantly increased PpINH1 expression,decreased VIN enzyme activity,and significantly higher sucrose content than did untreated fruit.As a result,the treated fruit had enhanced resistance to chilling injury.Collectively,our data show that the post-translational repression of VIN enzyme activity by PpINH1 helps maintain sucrose levels in peach fruit during cold storage,thereby improving resistance to chilling injury.

Field distribution of the Z_(2)topological edge state revealed by cathodoluminescence nanoscopy

Photonic topological insulators with robust boundary states can enable great applications for optical communication and quantum emission,such as unidirectional waveguide and single-mode laser.However,because of the diffraction limit of light,the physical insight of topological resonance remains unexplored in detail,like the dark line that exists with the crys-talline symmetry-protected topological edge state.Here,we experimentally observe the dark line of the Z_(2)photonic topo-logical insulator in the visible range by photoluminescence and specify its location by cathodoluminescence characteriza-tion,and elucidate its mechanism with the p-d orbital electromagnetic field distribution which calculated by numerical sim-ulation.Our investigation provides a deeper understanding of Z_(2)topological edge states and may have great signific-ance to the design of future on-chip topological devices.

Research on the Application of Big Data and Artificial Intelligence Technology in Computer Network

With the continuous development of social economy,science and technology are also in continuous progress,relying on the Internet technology of big data era has come in an all-round way.On the basis of the development of cloud computing and Internet technology,artificial intelligence technology has emerged as the times require.It also has more advantages.Applying it to computer network technology can effectively improve the data processing efficiency and quality of computer network technology,and improve the convenience for people’s life and production.This paper studies and analyzes the practical application requirements of computer network,and discusses the application characteristics and timeliness of artificial intelligence technology.

Finite-size-induced non-Hermitian phase transitions in real space

While non-Hermiticity provokes intriguing phenomena without Hermitian counterparts, e.g., the skin effect and the breakdown of bulk-boundary correspondence, attracting extensive attention both in fundamental physics and device engineering, the role of finite sizes therein remains elusive. Here, we propose a class of finite-size-induced non-Hermitian phase transitions, relying upon higher-order topological invariants associated with real-space wave functions. The phase diagrams for general non-Hermitian chiral models are further acquired to demonstrate our topological definition. Such phase transitions are elucidated qualitatively by an effective intercell coupling alteration that depends on finite sizes in respective directions. Besides, we mimic these phenomena by analogizing the circuit Laplacian in finite-size electric circuits with nonreciprocal couplings. The resultant admittance spectra agree with our theoretical predictions. Our findings shed light on the finite-size mechanism of non-Hermitian topological phase transitions and pave the way for applications in switching and sensing.

Halogen-based functionalized chemistry engineering for high-performance supercapacitors

Supercapacitors(SCs)are rated as the foremost efficient devices bridging the production and consumption of renewable energy.To address the ever-increasing energy requirements,it is indispensable to further develop high-performance SCs with merits of high energy-density,acceptable price and long-term stability.This review highlights the recent advances on halogen-based functionalized chemistry engineering in the state-of-the-art electrode system for high-performance SCs,primarily referring to the doping and decoration strategies of F,Cl,Br and I elements.Due to the discrepancy of electronegativity and atomic radius,the functionalization of each halogen element endows the substrate materials with different physicochemical properties,including energy bandgap structure,porosity distribution and surface affinity.The principle of halogen embedment into host materials by precisely controlling ionic adsorption and electronic structure is presented.And,the vital perspectives on the future challenges of halogen functionalization are also discussed.This work aims to deepen the understanding of halogen-based functionalized strategies to motivate further research for the development of high-performance SCs,and it also provides a prospect for exploring new material modification methods for electrochemical energy storage.

水稻强再生力种质创制及遗传分析

当前直接选育的再生稻专用品种较少,其制约的关键要素在于强再生力种质的缺乏.选用8个生产上大面积应用的恢复系,按4×4不完全双列杂交方式,通过系谱法进行定向选择和种质创新,以再生芽出鞘率为指标,采用加性-显性遗传模型,对恢复系再生力的遗传特性进行研究.结果表明:(1)再生力性状受控于加性效应基因和显性效应基因的共同作用,同时易受环境条件与栽培技术的影响;(2)再生力性状狭义遗传率(h^(2)N)和广义遗传率(h^(2)B)的估计值均达显著或极显著水平,而且广义遗传率明显大于狭义遗传率;(3)恢复系闽恢3301和亚恢627的再生力性状具有极显著或显著的正向加性效应和负向显性效应,适合作为筛选强再生力的亲本材料;(4)创制的新种质Ra201、Ra202、Ra212再生芽出鞘率较高,再生力强,其中Ra202低节位腋芽萌发优势明显,可作为亲本用于籼型水稻再生力基因挖掘和利用;(5)再生稻品种选育方法的研究进一步完善了传统育种技术,具有间接鉴定和早期筛选的优点,新种质创制和新品种选育取得了良好成效.

被子植物下胚轴细胞伸长的分子机理

作为一种正常的生命现象,植物下胚轴伸长是长期自然选择的结果,也是植物进行光合作用、实现自养的必要前提。但下胚轴过度伸长容易造成幼苗徒长,使植株长势弱,抗逆能力差,不利于产量提高和品质改良。该文综述了被子植物下胚轴的发育过程、下胚轴伸长的细胞学机制、植物激素及环境信号调控下胚轴细胞伸长分子机制的最新研究进展,并展望了未来的研究方向。

A novel cyclic peptide targeting LAG-3 for cancer immunotherapy by activating antigenspecific CD8^+ T cell responses

PD-1 and CTLA-4 antibodies offer great hope for cancer immunotherapy.However,many patients are incapable of responding to PD-1 and CTLA-4 blockade and show low response rates due to insufficient immune activation.The combination of checkpoint blockers has been proposed to increase the response rates.Besides,antibody drugs have disadvantages such as inclined to cause immune-related adverse events and infiltration problems.In this study,we developed a cyclic peptide C25 by using Ph.D.-C7C phage display technology targeting LAG-3.As a result,C25 showed a relative high affinity with human LAG-3 protein and could effectively interfere the binding between LAG-3 and HLA-DR(MHC-II).Additionally,C25 could significantly stimulate CD8^+T cell activation in human PBMCs.The results also demonstrated that C25 could inhibit tumor growth of CT26,B16 and B 16-OVA bearing mice,and the infiltration of CD8^+T cells was significantly increased while FOXP3^+Tregs significantly decreased in the tumor site.Furthermore,the secretion of IFN-γby CD8^+T cells in spleen,draining lymph nodes and especially in the tumors was promoted.Simultaneously,we exploited T cells depletion models to study the anti-tumor mechanisms for C25 peptide,and the results combined with MTT assay confirmed that C25 exerted anti-tumor effects via CD8+T cells but not direct killing.In conclusion,cyclic peptide C25 provides a rationale for targeting the immune checkpoint,by blockade of LAG-3/HLA-DR interaction in order to enhance anti-tumor immunity,and C25 may provide an alternative for cancer immunotherapy besides antibody drugs.

Topological photonic crystals:a review

The field of topological photonic crystals has attracted growing interest since the inception of optical analog of quantum Hall effect proposed in 2008.Photonic band structures embraced topological phases of matter,have spawned a novel platform for studying topological phase transitions and designing topological optical devices.Here,we present a brief review of topological photonic crystals based on different material platforms,including all-dielectric systems,metallic materials,optical resonators,coupled waveguide systems,and other platforms.Furthermore,this review summarizes recent progress on topological photonic crystals,such as higherorder topological photonic crystals,non-Hermitian photonic crystals,and nonlinear photonic crystals.These studies indicate that topological photonic crystals as versatile platforms have enormous potential applications in maneuvering the flow of light.

Surveillance of Noise Exposure Level in the Manufacturing Industry—China,2020

Introduction:Occupational noise exposure is a widespread issue in the manufacturing industry in China.Since 2019,the National Surveillance System for Occupational Hazards in the workplace was established to understand different occupational hazards,especially occupational noise,in workplaces in China.Methods:Both environmental and individual noise exposure levels were measured for 19,378 enterprises according to the Work Plan for Surveillance of Occupational Hazards in the Workplace(2020)issued by National Health Commission of the People’s Republic of China.Median and interquartile range(IQR)were calculated to describe the distribution of the noise exposure level by industry classification,enterprise-scale,and ownership type of the enterprise.Results:Overall,25.14%of the individual noise exposure samples exceeded the Chinese national standard among the selected enterprises.The overall median of environmental noise exposure level was 82.8 dB(A)in selected enterprises,while the median of individual noise exposure level was 81.3 dB(A).The individual noise exposure level in the manufacture of metal products,manufacture of motor vehicles,minisized enterprises,collective enterprises and private enterprises was relatively high.Conclusion:Occupational noise is still one of the occupational hazards that cannot be ignored in the manufacturing industry,especially in mini-sized and private enterprises.The risk of noise exposure in the target industry is still high and will pose a threat to the health of workers.

Recent advances in the synthesis of non-carbon two-dimensional electrode materials for the aqueous electrolyte-based supercapacitors

Supercapacitors(SCs) with high power density and long cycling span life are demanding energy storage devices that will be an attractive power solution to modern electronic and electrical applications. Numerous theoretical and experimental works have been devoted to exploring various possibilities to increase the functionality and the specific capacitance of electrodes for SCs. Non-carbon two-dimensional(2D)materials have been considered as encouraging electrode candidates for their chemical and physical advantages such as tunable surface chemistry, high electronic conductivity, large mechanical strength, more active sites, and dual non-faradaic and faradaic electrochemical performances. Besides, these 2D materials also play particular roles in constructing highway channels for fast ion diffusion. This concise review summarizes cutting-edge progress of some representative 2D non-carbon materials for the aqueous electrolyte-based SCs, including transition metal oxides(TMOs), transition metal hydroxides(TMHs), transition metal chalcogenides(TMCs), MXenes, metal-organic frameworks(MOFs) and some emerging materials. Different synthetic methods, effective structural designs and corresponding electrochemical performances are reviewed in detail. And we finally present a detailed discussion of the current intractable challenges and technical bottlenecks, and highlight future directions and opportunities for the development of next-generation high-performance energy storage devices.

Distinct structural characteristics define a new subfamily of Mycoplasma ferritin

Ferritins can generally be divided into four subfamilies based on their structural characteristics,namely,the classic ferritins(Ftns),bacterioferritins(Bfrs),DNA-binding proteins from starved cells(Dps’),and encapsulated ferritins(Enc Ftns).However,the ferritin from Mycoplasma penetrans(Mpef)possesses a particular ferroxidase center with an extreme low activity and exhibits unusual characteristics,indicating that it could be a member of a quite different subfamily of ferritins.Hereby,the crystal structure of the ferritin from Ureaplasma urealyticum(Uurf)is presented,Mpef and Uurf have very similar properties,though they display very low sequence similarity.Thus,ferritins from Mycoplasma with these unique properties do not belong to any known subfamily,but they should rather be placed in a novel ferritin subfamily,which we term Mycoplasma Ferritin(Mfr).

Intrinsic superflat bands in general twisted bilayer systems

Twisted bilayer systems with discrete magic angles,such as twisted bilayer graphene featuring moirésuperlattices,provide a versatile platform for exploring novel physical properties.Here,we discover a class of superflat bands in general twisted bilayer systems beyond the low-energy physics of magic-angle twisted counterparts.By considering continuous lattice dislocation,we obtain intrinsic localized states,which are spectrally isolated at lowest and highest energies and spatially centered around the AA stacked region,governed by the macroscopic effective energy potential well.Such localized states exhibit negligible inter-cell coupling and support the formation of superflat bands in a wide and continuous parameter space,which can be mimicked using a twisted bilayer nanophotonic system.Our finding suggests that general twisted bilayer systems can realize continuously tunable superflat bands and the corresponding localized states for various photonic,phononic,and mechanical waves.

Occupational Dust Hazards and Risk Assessment of Coal-Fired Thermal Power Plants of Different Capacities—China,2017–2019

Summary What is already known about this topic?Silica dust and coal dust are the main occupational hazards in coal-fired thermal power plants,which mainly exist in coal transportation workplaces,combustion milling workplaces,and ash removal workplaces.What is added by this report?The overall environmental and personal dust exposure levels decrease with an increase in the capacity of coalfired thermal power plants.

Prognostic implications of elevated pulmonary artery systolic pressure on 6-month mortality in elderly patients with acute myocardial infarction

Background:Pulmonary artery systolic pressure(PASP)has often been evaluated as an indicator of heart failure,but the relationship between PASP and the prognosis of elderly patients with acute myocardial infarction(AMI)is not well understood.Methods:The medical data of 3460 hospitalized elderly patients diagnosed with AMI between January 2013 and June 2018 were reviewed.PASP was calculated usingtransthoracic color Doppler ultrasonography.Patients were grouped accordingtotheir admission PASP results as follows:Group A,PASP≤30 mmHg;Group B,30 mmHg<PASP≤50 mmHg;and Group C,PASP≥51 mmHg.The primary endpoint was all-cause death 6 months following AMI.Multiple Cox regression analysis was used to identify independent risk factors for 6-month mortality in elderly patients with AMI.Results:PASP was associated with age,Killip classification,AMI site,and decreased ejection fraction in elderly patients.After adjusting for clinical and echocardiographic parameters in the Cox model,PASP was found to be significantly related to all-cause mortality.In receiver operating characteristic analysis,a PASP of>34 mmHg had a sensitivity of 62.3%and specificity of 65.7%for predicting 6-month all-cause death after AMI.Conclusion:PASP at admission is a useful marker for predicting short-term mortality in elderly patients with AMI.This finding could be used to help identify high-risk patients and make appropriate clinical decisions.