自组装协同催化高选择性合成卤代芳烃

卤代芳烃是非常重要的合成砌块,广泛应用于农用化学品、材料和药物等的合成。芳烃的亲电取代卤化反应是制备芳基卤化物最简单的方法,但是富电子芳烃的卤化反应存在区域选择性差的挑战。本实验采用自组装协同催化策略,以环己基苯溴化反应为模型反应,高选择性合成溴代芳烃,进而应用于卤代芳烃的高选择性合成。在加深学生芳烃亲电取代卤化反应的同时,也向学生传授自组装、协同催化和路易斯酸碱催化等重要知识,加深学生对亲电取代反应机理和离子型中间体的了解。实验主要由卤代芳烃的合成、机理探究及实验普适性三部分组成,包含多种有机实验基本操作,涉及反应监测、分离纯化、产物表征等多个重要环节,实验整体时长7小时,安全性高,可操作性强,适合本科实验教学开设。本实验秉持科研反哺教学的理念,将新的科研成果转化为人才培养内容,有助于提高学生的科研创新与实践能力。

The chance of sodium titanate anode for the practical sodium-ion batteries

Supporting sustainable green energy systems,there is a big demand gap for grid energy storage.Sodiumion storage,especially sodium-ion batteries(SIBs),have advanced significantly and are now emerging as a feasible alternative to the lithium-ion batteries equivalent in large-scale energy storage due to their natural abundance and prospective inexpensive cost.Among various anode materials of SIBs,beneficial properties,such as outstanding stability,great abundance,and environmental friendliness,make sodium titanates(NTOs),one of the most promising anode materials for the rechargeable SIBs.Nevertheless,there are still enormous challenges in application of NTO,owing to its low intrinsic electronic conductivity and collapse of structure.The research on NTOs is still in its infancy;there are few conclusive reviews about the specific function of various modification methods.Herein,we summarize the typical strategies of optimization and analysis the fine structures and fabrication methods of NTO anodes combined with the application of in situ characterization techniques.Our work provides effective guidance for promoting the continuous development,equipping NTOs in safety-critical systems,and lays a foundation for the development of NTO-anode materials in SIBs.

In-situ/operando characterization techniques in lithium-ion batteries and beyond

Nowadays,in-situ/operando characterization becomes one of the most powerful as well as available means to monitor intricate reactions and investigate energy-storage mechanisms within advanced batteries.The new applications and novel devices constructed in recent years are necessary to be reviewed for inspiring subsequent studies.Hence,we summarize the progress of in-situ/operando techniques employed in rechargeable batteries.The members of this large family are divided into three sections for introduction,including bulk material,electrolyte/electrode interface and gas evolution.In each part,various energy-storage systems are mentioned and the related experimental details as well as data analysis are discussed.The simultaneous strategies of various in-situ methods are highlighted as well.Finally,current challenges and potential solutions are concluded towards the rising influence and enlarged appliance of in-situ/operando techniques in the battery research.

Adaptive backstepping-based NTSM control for unmatched uncertain nonlinear systems

An adaptive backstepping-based non-singular termi- nal sliding mode （NTSM） control method is proposed for a class of uncertain nonlinear systems in the parameteric-strict feedback form. The adaptive control law is combined with the first n - 1 steps of the backstepping method to estimate the unknown pa- rameters of the system. In the nth step, an NTSM control strategy is utilized to drive the last state of the system to converge in a finite time. Furthermore, the derivate estimator is used to obtain the derivates of the states of the error system; the higher-order non-singular terminal sliding mode control （HONTSMC） law is de- signed to eliminate the chattering and make the system robust to both matched and unmatched uncertainties. Compared to the adaptive backstepping-based linear sliding mode control method （LSMC）, the proposed method improves the convergence rate and the steady-state tracking accuracy of the system, and makes the control signal smoother. Finally, the compared simulation results are presented to validate the method.

Response of Japanese anchovy(Engraulis japonicus)to the Pacific Decadal Oscillation in the Yellow Sea over the past 400 a

Quantitative identification of long-term changes in the abundance of Japanese anchovy(Engraulis japonicus)in the Yellow Sea is particularly important for understanding evolutionary processes of the Yellow Sea ecosystem.Unfortunately,the driving mechanisms of climate variability on the anchovy are still unclear due to the lack of long-term observational data.In this study,we used the fish scale deposition rate in the central Yellow Sea to reconstruct the time series of the anchovy stock over the past 400 a.On this basis,we further explored the impacts of the Pacific Decadal Oscillation(PDO)on the anchovy.Our results show that the anchovy stock is positively correlated with the PDO on a decadal time scale.In addition,anchovy abundance was relatively high during1620–1860 AD(the Little Ice Age,LIA),though in a state of constant fluctuation;anchovy abundance maintained at a relatively low level after~1860 AD.In particular,followed by overfishing since the 1980 s,the anchovy stock has declined sharply.Based on these findings,we infer that fluctuations of the anchovy stock may be regulated by basin-scale“atmosphere–ocean”interactions.Nevertheless,the role of overfishing should not be ignored.

Smart palm-size optofluidic hematology analyzer for automated imaging-based leukocyte concentration detection

A critical function of flow cytometry is to count the concentration of blood cells,which helps in the diagnosis of certain diseases.However,the bulky nature of commercial flow cytometers makes such tests only available in hospitals or laboratories,hindering the spread of point-of-care testing(POCT),especially in underdeveloped areas.Here,we propose a smart Palm-size Optofluidic Hematology Analyzer based on a miniature fluorescence microscope and a microfluidic platform to lighten the device to improve its portability.This gadget has a dimension of 35×30×80 mm and a mass of 39 g,less than 5%of the weight of commercially available flow cytometers.Additionally,automatic leukocyte concentration detection has been realized through the integration of image processing and leukocyte counting algorithms.We compared the leukocyte concentration measurement between our approach and a hemocytometer using the Passing-Bablok analysis and achieved a correlation coefficient of 0.979.Through Bland-Altman analysis,we obtained the relationship between their differences and mean measurement values and established 95%limits of agreement,ranging from−0.93×10^(3)to 0.94×10^(3)cells/μL.We anticipate that this device can be used widely for monitoring and treating diseases such as HIV and tumors beyond hospitals.

Efficient Chemical Prelithiation with Modificatory Li^(+) Solvation Structure Enabling Spatially Homogeneous SEI toward High Performance SiO_(x) Anode

Chemical prelithiation is widely proven to be an effective strategy to address the low initial coulombic efficiency(ICE)of promising SiO_(x) anode.Though the reagent composition has been widely explored,the Li^(+) solvation structure,which practically plays the cornerstone role in the prelithiation ability,rate,uniformility,has rarely been explored.A novel environmentally-friendly reagent with weak solvent cyclopentyl methyl ether(CPME)is proposed that enables both improved ICE and spatial homogeneous solid electrolyte interphase(SEl).And the prelithiation behavior and mechanism were explored focused on the Li^(+) solvation structure.Both theoretical investigation and spectroscopic results suggest that weak solvent feature of CPME reduces the solvent coordination number and decreases the Li^(+) desolvation energy.

肿瘤相关巨噬细胞在甲状腺乳头状癌中的分布及临床意义的初探

目的:初步探讨肿瘤相关巨噬细胞(tumor-associated macrophages,TAMs)及M2型TAMs与甲状腺乳头状癌(papillary thyroid carcinoma,PTC)临床病理特征的关系。方法:选取2010年1月至2017年12月云南省肿瘤医院昆明医科大学第三附属医院就诊的68例患者的临床资料,其中甲状腺癌51例(PTC 42例,甲状腺鳞状细胞癌9例),甲状腺良性病变17例。免疫组织化学法检测术后病理组织中TAMs和M2型TAMs的分布情况,并分析其与患者临床病理特征的关系。结果:甲状腺癌组织中CD68^(+)TAMs、CD206^(+)TAMs和CD68^(+)/CD206^(+)TAMs的分布强度均高于甲状腺良性病变(P<0.05)。在PTC组织内存在CD68−/CD206^(+)TAMs形式的分布。42例PTC中,有淋巴结转移组及肿瘤大小≥2 cm组中CD68^(+)TAMs和CD68^(+)/CD206^(+)TAMs的分布强度高于无淋巴结转移组和肿瘤大小<2 cm组(P<0.05)。在PTC大小<2 cm及Ⅰ期或Ⅱ期的情况下,CD206^(+)TAMs分布强度高于CD68^(+)TAMs(均P<0.001)。PTC组织中CD206^(+)TAMs分布强度与CD68^(+)TAMs分布强度呈正相关(P<0.05)。在PTC患者的T3、TgAb、FT3及FT4正常组与异常组之间CD68^(+)TAMs的分布差异具有统计学意义(P<0.05);CD68^(+)/CD206^(+)TAMs的分布分别在PTC患者的T3、FT3及FT4正常组与异常组之间差异具有统计学意义(P<0.05)。结论:TAMs、M2型TAMs对PTC的发生具有一定促进作用,TAMs促进PTC颈部淋巴结转移、肿瘤的生长及影响甲状腺激素水平的调节;在PTC微环境中未发现M2型TAMs从属于TAMs的关系,而在PTC早期微环境中主要是以M2型TAMs为主。

Quantitatively mapping local quality of super-resolution microscopy by rolling Fourier ring correlation

In fluorescence microscopy,computational algorithms have been developed to suppress noise,enhance contrast,and even enable super-resolution(SR).However,the local quality of the images may vary on multiple scales,and these differences can lead to misconceptions.Current mapping methods fail to finely estimate the local quality,challenging to associate the SR scale content.Here,we develop a rolling Fourier ring correlation(rFRC)method to evaluate the reconstruction uncertainties down to SR scale.To visually pinpoint regions with low reliability,a filtered rFRC is combined with a modified resolution-scaled error map(RSM),offering a comprehensive and concise map for further examination.We demonstrate their performances on various SR imaging modalities,and the resulting quantitative maps enable better SR images integrated from different reconstructions.Overall,we expect that our framework can become a routinely used tool for biologists in assessing their image datasets in general and inspire further advances in the rapidly developing field of computational imaging.

Application of biocompatible custom ceria nanoparticles in improving the quality of liver grafts for transplantation

Liver transplantation(LT),an ultimate and vital method for treating end-stage liver disease,is often accompanied by ischemiareperfusion injury(IRI)resulting from warm or cold ischemia of the donor liver.Organ protection techniques are used to improve the quality of liver grafts(from retrieval to implantation).Reactive oxygen species(ROS)cause oxidative stress,which is considered a crucial factor in IRI after LT.Nano antioxidants capable of scavenging ROS alleviate IRI in multiple types of organs and tissues.In this study,we synthesized ceria nanoparticles(NPs)with antioxidant properties using a pyrolysis method and covered them with phospholipid-polyethylene glycol to improve their biocompatibility in vivo.We investigated the potential organprotective effect of ceria NPs and the underlying mechanisms.Ceria NPs promoted liver function recovery after LT by attenuating IRI in liver grafts in vivo.The protective effect of ceria NPs on liver grafts was investigated by applying hypothermic oxygenated machine perfusion ex vivo.Ceria NPs attenuated hypoxia reoxygenation-or H_(2)O_(2)-induced hepatocyte injury by enhancing mitochondrial activity and ROS scavenging in vitro.These effects may be associated with the activation of the nuclear factor erythroid-derived 2-related factor 2(Nrf2)/Kelch-like ECH-associated protein 1(Keap1)/heme oxygenase 1(HO-1)signaling pathway.In conclusion,ceria NPs may serve as a promising antioxidant agent for the treatment of hepatic IRI after LT.

Dual-response of multi-functional microsphere system to ultrasound and microenvironment for enhanced bone defect treatment

Using bone tissue engineering strategies to achieve bone defect repair is a promising modality.However,the repair process outcomes are often unsatisfactory.Here we properly designed a multi-functional microsphere system,which could deliver bioactive proteins under the dual response of ultrasound and microenvironment,release microenvironment-responsive products on demand,reverse bone injury microenvironment,regulate the immune microenvironment,and achieve excellent bone defect treatment outcomes.In particular,the MnO_(2) introduced into the poly(lactic-co-glycolic acid)(PLGA)microspheres during synthesis could consume the acid produced by the degradation of PLGA to protect bone morphogenetic protein-2(BMP-2).More importantly,MnO_(2) could consume reactive oxygen species(ROS)and produce Mn^(2+)and oxygen(O_(2)),further promoting the repair of bone defects while reversing the microenvironment.Moreover,the reversal of the bone injury microenvironment and the depletion of ROS promoted the polarization of M1 macrophages to M2 macrophages,and the immune microenvironment was regulated.Notably,the ultrasound(US)irradiation used during treatment also allowed the on-demand release of microenvironment-responsive products.The multi-functional microsphere system combines the effects of on-demand delivery,reversal of bone injury microenvironment,and regulation of the immune microenvironment,providing new horizons for the clinical application of protein delivery and bone defect repair.

Molecular behaviors in thin film lubrication——Part two: Direct observation of the molecular orientation near the solid surface

Over the past twenty years, thin film lubrication(TFL) theory has been used to characterize the molecular behaviors in lubrication films thinner than 100 nm, effectively bridging the gap between elastohydrodynamic lubrication and boundary lubrication. Unfortunately, to date, the TFL molecular model proposed in 1996 has not been directly proven by experimental detection. Herein, a method based on surface-enhanced Raman spectroscopy was developed to show both the packing and orienting of liquid molecules in the TFL regime. By trapping liquid crystal molecules between a structured silver surface and a glass surface, molecular ordering states dominated by shear effect and surface effect were successfully distinguished. A nanosandwich structure consisting of an adsorbed layer, an ordered-molecule layer, and a fluid layer was demonstrated. Molecule imaging in TFL was achieved. Our results illustrate the molecular behaviors and lubrication mechanism in nanoconfined films and facilitate the lubrication design of nanoelectromechanical and microelectromechanical systems.

Compact logic operator utilizing a single-layer metasurface

In this paper, we design and demonstrate a compact logic operator based on a single-layer metasurface at microwave frequency. By mapping the nodes in the trained fully connected neural network(FCNN) to the specific unit cells with phase control function of the metasurface, a logic operator with only one hidden layer is physically realized. When the incident wave illuminates specific operating regions of the metasurface, corresponding unit cells are activated and can scatter the incident wave to two designated zones containing logical information in the output layer. The proposed metasurface logic operator is experimentally verified to achieve three basic logic operations(NOT, OR, and AND) under different input signals. Our design shows great application potential in compact optical systems, low-power consumption information transmission, and ultrafast wave-based full signal processing.

单分子视踪技术揭示SARS-CoV-2病毒利用动态的丝状伪足入侵细胞

SARS-CoV-2病毒侵袭细胞的分子机制已被初步探索,但关于其如何调节亚细胞结构重塑从而侵袭多种器官及细胞类型尚不清楚.本文利用活细胞实时成像技术揭示了SARS-CoV-2病毒颗粒通过宿主细胞丝状伪足进入靶细胞的动态过程.利用荧光标记的SARS-CoV-2病毒样颗粒(VLP)和稀疏去卷积算法成像技术,发现VLP利用丝状伪足以“冲浪”和“抓取”两种模式到达入侵点,以避免病毒在细胞膜上随机搜索入侵位点,此外,结合力学模拟实验,阐明了病毒诱导丝状伪足的形成和丝状伪足的回缩速度分别取决于细胞骨架动力学和病毒重力引起的底物表面摩擦阻力.进一步研究发现SARS-CoV-2通过丝状伪足进入细胞的过程依赖于小G蛋白Cdc42(细胞分裂周期蛋白42)活性和肌动蛋白相关蛋白fasin(肌动蛋白结合蛋白)、formin(成核蛋白)和Arp2/3(肌动蛋白相关蛋白2/3复合物).综上所述,本文结果强调了SARS-CoV-2感染能对宿主细胞的微丝骨架进行时空调节,使细胞形成丝状伪足作为病毒进入的“高速轨道”,丝状伪足形成相关蛋白及其信号通路可作为潜在的抗病毒靶标.

Pt overlayer for direct oxidation of CH_(4)to CH_(3)OH

Highly selective conversion of methane(CH_(4))to methanol(CH_(3)OH)is an emerging attractive but challenging process for future development of hydrogen economy,which requires efficient catalysts.Herein,we systematically explore the catalytic properties of Pt(111)overlayer on transition metal oxides(TMOs)for CH_(4) conversion by first principles calculations.The Pt(111)monolayer supported by Ce-terminated CeO_(2)(111)substrate exhibits high activity and selectivity for CH_(4) conversion to CH_(3)OH,with the kinetic barrier of rate-limiting step of 1.05 eV.Intriguingly,the surface activity of Pt overlayer is governed by its d-band center relative to the energy of bonding states of adsorbed molecules,which in turn depends on the number of charge transfer between Pt(111)monolayer and underlying TMOs substrates.These results provide useful insights in the design of metal overlayers as catalysts with high-ultra performance and atomic utilization.

Patterning catalyst via inkjet printing to grow single-walled carbon nanotubes

Controlled growth of patterned single-walled carbon nanotubes (SWNTs) is an important issue in many applications. Herein, we demonstrated a method to pattern catalyst via inkjet printing for the growth of SWNTs, using metal salt solutions as the inks and an ordinary office-use printer. We printed water solutions of cobalt acetate on hydrophilic Si substrates and grew high quality SWNT films. The composition of the precursor solutions and the hydrophilicity of the substrates were crucial factors to the patterning.

A hybrid method for product low-end disruptive innovation

Product innovation is often a process for improving existing products.Low-end disruptive innovation(LDI)enables a product to meet the most price-sensitive customers in the low-end market.The existing LDI methods are mainly based on unnecessary characteristics of disruptive innovations.Thus,they cannot easily identify and respond to the LDI design needs.This study proposes a hybrid method for the product LDI in two levels of the product design based on the summarized definition and essential characteristics of LDI.Feasible areas of the product LDI are determined using a hybrid relational function model to identify the maturity of dominant technologies.The technologies are identified through the technical search and evaluation of the feasible area for innovation to form an initial LDI scheme.Then,the product function is optimized using the trimming concept of theory of inventive problem solving based on the characteristics of LDI.The final LDI scheme is formed and evaluated based on the essential characteristics of the product LDI.The feasibility of the proposed method is verified in the design of a new dropping pill machine.