Selected aptamer specially combing 5-8F cells based on automatic screening instrument

Since the concept of aptamer emerged, many scientists have launched a rich field of research around it. However, few nucleic acids aptamer which use cell as target can be put into practical applications. We believe that a great deal of this lies in the complexity and irreproducibility of aptamer screening experiments themselves. The complexity is due to the cumbersome processes and the technical requirements for laboratory personnel, whereas irreproducibility arises from the fact that the starting point of such screens is nucleic acid libraries with random fragments, and that different libraries directly determine the differences or even the success or failure of screening results. The complexity and irreproducibility mentioned above, in turn, lead to the inability of this experiment to unfold on a large scale, which naturally cannot lead to excellent results for practical applications. In response to this problem, our group has developed an instrument for automated screening of tumor cell nucleic acid aptamers and characterized the properties of nucleic acid aptamers obtained using this instrument in a comprehensive manner.     

A Unique Layered Cu-formate Hydrate of Cu(HCOO) 2·1/3H2O: Structures,Dehydration, and Thermal and Magnetic Properties

Anew layered Cu-formate hydrate of Cu(HCOO)₂·1/3H₂O is unique in its water content and the strongly waved (4,4) Cu-formate layers held by interlayer weak axial Cu-O_formate bonds and O-H_water···O_formate hydrogen bonds. The crystal is in orthorhombic space group Pbcn, with cell parameters at 80 K:a=7.9777(2) Å, b=7.3656(2) Å, c=21.0317(5) Å(1 Å=10⁻¹ nm), and V=1235.83(5) ų. The Cu²⁺ ions are in the environments of a square pyramid and elongated octahedron, in a ratio of 1/2 within the structure. In the layer, Cu²⁺ ions are connected by anti-anti formates via short basal Cu-O bonds. The structure remains unchanged until the dehydration that produces the layered anhydrous β-Cu(HCOO)₂, and the possible transformation mechanism, supported by diffraction evidence, is the reorganization of the Cu-O_formate bonds across the parent layers after dehydration. The two phases exhibit anisotropic thermal expansion behaviors closely relevant to the transverse thermal vibrations of the constituents. Cu(HCOO)₂·1/3H₂O is a 2-dimensional Heisenberg antiferromagnet, and exhibits a global spin-canted antiferromagnetism with the Néel temperature of 32.1 K. This is not only higher than that of the magnetically denser β-Cu(HCOO)₂, but also the highest among the copper formate frameworks.     

A near-infrared phosphor doped with Cr3+ towards zero-thermal-quenching for high-power LEDs

Cr³⁺-doped phosphors show significant application potential in near-infrared (NIR) light-emitting diodes (LEDs). However, the development of thermally stable and efficient NIR phosphors still faces enormous challenges. Herein, NIR phosphors K₂NaMF₆:Cr³⁺ (M³⁺ = Al³⁺, Ga³⁺, and In³⁺) were synthesized by the hydrothermal method. The represented K₂NaAlF₆:Cr³⁺ phosphor can be effectively excited by blue light (～430 nm) to present broadband emission at half a maximum of 96 nm peaking at ～ 728 nm. Meanwhile, the K₂NaAlF₆:Cr³⁺ phosphor exhibits excellent internal quantum efficiency (IQE = 68.08%) and nearly zero-thermal-quenching behavior, which is able to maintain 96.5% emission intensity at 150 °C of the initial value at 25 °C. The NIR phosphor-converted LED was fabricated based on K₂NaAlF₆:Cr³⁺ phosphor and a blue LED chip, showing a NIR output power of 394.39 mW at 300 mA with a high photoelectric conversion efficiency of 10.9% at 20 mA. Using the high-power NIR LED as a lighting source, transparent and quick veins imaging as well as non-destructive testing were demonstrated, suggesting the NIR phosphor has a wide range of practical applications.     

Challenges and Development of Composite Solid Electrolytes for All-solid-state Lithium Batteries

All-solid-state lithium batteries are considered to be a new battery system with great development potential and application prospects due to the advantages of high energy density and high security.As a key component of all-solid-state lithium batteries,the development of solid-state electrolytes has received extensive attention in recent years,but most solid electrolytes still exhibit problems,such as low ion conductivity and poor interface compatibility.The design of composite solid-state electrolyte materials with both excellent electrochemical and mechanical properties is an effective way to develop all-solid-state lithium batteries.This review introduces different types of pure component solid electrolytes and analyzes their respective advantages and characteristics firstly.Furthermore,the research progress of composite electrolytes in preparation method,ionic conduction,suppression of lithium dendrites,and the improvement of electrochemical performances are reviewed from the perspective of composite electrolyte structure design,which is to meet different performance requirements.And the future development direction and trend of composite electrolytes are prospected.     

碳辅助金属配合物热解法制备高含量Fe-N4单原子催化剂用于氧还原反应

单原子催化剂凭借其超高的原子利用率及在某些反应中表现出的出色催化效果,被认为是最有前途的电催化剂之一,引起了研究人员的极大热情和兴趣.制备高金属含量的单原子催化剂是基础研究和实际应用的前提和关键.然而,由于原子表面自由能随着尺寸的减小而急剧增加,在制备和催化过程中,单原子催化剂的金属原子很容易聚集成团簇甚至颗粒,因此如何制备高负载量的单原子催化剂仍然是一个不小的挑战.在众多单原子催化剂中,非贵金属中铁基单原子被认为是燃料电池中的Pt催化剂的有效替代品.在燃料电池的核心反应–电化学氧还原反应中,Fe-N_x被证明是铁单原子催化剂中的主要活性中心.因此,为了获得更好的氧还原性能,提高铁单原子催化剂中Fe-N_x的含量就显得非常关键.前期已报道了一些关于制备高Fe含量的铁单原子催化剂材料的策略,例如空间限域策略和配位合成策略.其中卟啉和葡萄糖作为配位剂,双氰胺和三聚氰胺可热解成氮掺杂碳材料以捕获金属原子,形成M-N_x.同时,具有高比表面积的富氧碳载体可以通过掺杂氮来作为固定金属原子的位点.我们开发了一种简单直接的方法,通过碳辅助金属配合物热解法制备高金属含量的Fe-N4单原子催化剂,即在最佳碳化温度800℃、三聚氰胺存在下对氮掺杂多孔碳辅助分散铁邻苯二胺配合物进行热解.在该方法中,氮掺杂多孔碳是一种具有丰富氮缺陷,高表面积(1267 m²?g^–1)和良好分散性的多孔生物质碳材料.邻苯二胺作为含两个氨基的二齿配体,可以很容易地与过渡金属配位,形成稳定的平面四配位络合物.此外,由于在高温条件下过渡金属的催化作用,邻苯二胺也被用作氮掺杂碳的前体.因此,氮掺杂多孔碳和邻苯二胺是合成高金属含量铁单原子催化剂的关键前驱体.通过X射线光电子能谱,大角度环形暗场扫描透射电子显微镜和X射线吸收精细结构光谱表征,发现所制备的铁单原子催化剂中铁原子以单个原子的形式锚固在碳载体上,并与碳基质的四个掺杂氮原子配位,得到Fe-N₄的构型.通过调节Fe前驱体量,铁单原子催化剂中Fe的最高负载量达到7.5 wt%,在目前已经报道的铁单原子催化剂中排第四.电化学氧还原测试表明,在0.10 M KOH溶液中,随着铁含量的增加,铁单原子催化剂的氧还原性能逐渐提高.其中250Fe-SA/NPC-800样品表现出最高起始电位0.97 V和最正的半波电位0.85 V,可与市售的40%Pt/C催化剂相媲美.和已报道的铁单原子催化剂相比,由于我们制得的催化剂的比表面积较低,只有247 m²?g^–1,所以制约了催化剂的性能.在混合动力学势域中,根据Koutecky-Levich方程计算得出的电子转移数约为3.6,表明250Fe-SA/NPC-800主要催化四电子转移过程,这可以归因于以Fe-N₄活性中心降低了四电子过程中关键中间体的形成能垒及过程的自由能变化.此外,250Fe-SA/NPC-800展现了较高的电化学稳定性.连续工作6 h后,250Fe-SA/NPC-800保留了超过87%的电流密度,而Pt/C表现出明显的衰减,仅保留了49%.     

Interference effects of two and three super-tall buildings under wind action

Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data processing.In this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure measurements.Furthermore,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors.     

Elxed Point Theorem of Composition g-Contraction Mapping and its Applications

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Effects of an asymmetrical confined flow on a rectangular cylinder

The effects of an asymmetric confined flow on a cylinder of rectangular cross-section are investigated and discussed. Experiments are performed in a wind tunnel by placing cylinders of different cross-sections at various elevations from the floor of the test-section. The Reynolds number is varied within the range 6×10³–4×10⁴. Forces exciting the cylinder are measured by built-in dynamometers placed inside the cylinder structure. The flow is characterized by mean and fluctuating local velocity components to define the inflow distribution and the ensuing wake region. The mean dimensionless force coefficients are then calculated and analyzed. The frequency analysis of the force components acting on the cylinder provides the dynamic characterization of the loading and of the wake shedding. The experimental results highlight that the presence of the wall strongly influences the system dynamics also when the cylinder is placed at a relatively large elevation from the wall itself. The cylinder aspect ratio governs effects of the wall condition on the force coefficients and the Strouhal number.     

Sensitive Stripping Determination of Cadmium(II) and Lead(II) on Disposable Graphene Modified Screen‐Printed Electrode

In the present work, a sensitive, facile and disposable sensing platform for trace analysis of heavy metal ions was developed at the Bi modified graphene‐poly(sodium 4‐styrenesulfonate) composite film screen printed electrode (GR/PSS/Bi/SPE). The GR/PSS/Bi/SPE improved sensitivity and linearity due to the functionalization of graphene with negatively charged PSS providing more absorbing sites. The detection limit of the GR/PSS/Bi/SPE is found to be 0.042 µg L^?1 for Cd²⁺ and 0.089 µg L^?1 for Pb²⁺ with linear responses of Cd²⁺ and Pb²⁺ in the range of 0.5–120 µg L^?1. Finally, the practical application was confirmed in real water with satisfactory results.     

Surfacial carbonized palygorskite as support for high-performance Pt-based electrocatalysts

Pt nanoparticles deposited on a low-cost, surfacial, carbonized palygorskite (Pt/C-PLS) prepared by carbonizing sucrose were evaluated as a methanol oxidation catalyst for direct methanol fuel cells. Transmission electron microscopy and Fourier transfrom infrared spectrophotometry analyses revealed that carbon was formed on the surface of PLS and that free silica presented in the C-PLS support. The catalytic activity of methanol oxidation of Pt/C-PLS was higher than that of Pt/C, and the former catalyst had better CO tolerance.