The qualitative boundary behavior of blow-up solutions of the super-Liouville equations

Continuing our work on the boundary value problem for super-Liouville equation, we study the qualitative behavior of boundary blow-ups. The boundary condition is derived from the chirality conditions in the physics literature, and is geometrically natural. In technical terms, we derive a new Pohozaev type identity and provide a new alternative, which also works at the boundary, to the classical method of Brézis–Merle.     

Coalescence of 3-phenyl-propynenitrile on Cu(111) into interlocking pinwheel chains

3-phenyl-propynenitrile (PPN) adsorbs on Cu(111) in a hexagonal network of molecular trimers formed through intermolecular interaction of the cyano group of one molecule with the aromatic ring of its neighbor. Heptamers of trimers coalesce into interlocking pinwheel-shaped structures that, by percolating across islands of the original trimer coverage, create the appearance of gear chains. Density functional theory aids in identifying substrate stress associated with the chemisorption of PPN's acetylene group as the cause of this transition.     

折叠交叉立方体的分支边连通度

r-分支连通度(边连通度)是衡量大型互连网络可靠性和容错性的一个重要参数.设G是连通图且r是非负整数,如果G中存在某种点子集(边子集)使得G删除这种点子集(边子集)后得到的图至少有r个连通分支.则所有这种点子集(边子集)中基数最小的点子集(边子集)的基数称为图G的r-分支连通度(边连通度).n-维折叠交叉立方体FCQn是由交叉立方体CQn增加2n-1条边后所得.该文利用r-分支边连通度作为可靠性的重要度量,对折叠交叉立方体网络的可靠性进行分析,得到了折叠交叉立方体网络的2-分支边连通度,3-分支边连通度,4分支边连通度.确定了折叠交叉立方体FCQn的r-分支边连通度.     

Design and Fabrication of a Biomimetic Nanochannel for Highly Sensitive Arginine Response in Serum Samples

Inspired from their biological counterparts, chemical modification of the interior surface of nanochannels with functional molecules may provide a highly efficient means to control ionic or molecular transport through nanochannels. Herein, we have designed and prepared a aldehyde calix[4]arene (C4AH), which was attached to the interior surface of a single nanochannel by using a click reaction, and that showed a high response for arginine (Arg). Furthermore, the nanofluidic sensing system has been challenged with complex matrices containing a high concentration of interfering sequences and serum. Based on this finding, we believe that the artificial nanochannel can be used for practical Arg‐sensing devices, and be applied in a biological environment.     

纳米酶

纳米酶(Nanozymes)是由我国科学家首次提出的新概念,它是一类具有生物催化功能的纳米材料,能够基于特定的纳米结构催化天然酶的底物并作为酶的代替品。自2007年首次报道以来,全球已有来自于55个国家的420多个研究机构证实了纳米酶的普遍规律。纳米酶的发现第一次揭示纳米材料蕴含一种独特的纳米效应——类酶催化效应。纳米酶作为一种新材料,既有纳米材料本身的理化性质,又有类似酶的催化功能,兼具天然酶与人工酶的优势于一身。其中,纳米结构不仅赋予纳米酶高效催化功能,而且使纳米酶比天然酶稳定,易于规模化生产。另外,纳米酶独特的多酶活性将为设计廉价、稳定、各种各样全新的催化级联反应提供功能分子。纳米酶是多学科交叉融合的典范,2022年被IUPAC评为十大化学新兴技术。在全球从事化学、酶学、材料学、生物学、医学、理论计算等多领域科学家的共同推进下,如今纳米酶已经成为新的研究热点。我国科学家在这一新兴领域一直发挥着引领作用,解析了纳米酶的构-效关系,将其催化活性提高了约1万倍,实现了超越天然酶的理性设计,创造了全球首个纳米酶产品,出版了纳米酶学英文专著,发布纳米酶术语及中国/国际标准化。更可喜的是,纳...     

Synthesis and Characterization of β‐Diketiminate Aluminum Compounds and Their Use in the Ring‐Opening Polymerization of ε‐Caprolactone

Four aluminum alkyl compounds, [CH{(CH₃)CN‐2,4,6‐MeC₆H₂}₂AlMe₂] ( 1 ), [CH{(CH₃)CN‐2,4,6‐MeC₆H₂}₂AlEt₂] ( 2 ), [CH{(CH₃)CN‐2‐iPrC₆H₄}₂AlMe₂] ( 3 ), and [CH{(CH₃)CN‐2‐iPrC₆H₄}₂AlEt₂] ( 4 ), bearing β‐diketiminate ligands [CH{(Me)CN‐2,4,6‐MeC₆H₂}]₂ (L¹H) and [CH{(Me)CN‐2‐ⁱPrC₆H₄}]₂ (L²H) were obtained from the reactions of trimethylaluminum, triethylaluminum with the corresponding β‐diketiminate, respectively. All compounds were characterized by ¹H NMR and ¹³C NMR spectroscopy, single‐crystal X‐ray structural analysis, and elemental analysis. Compounds 1 – 4 were found to catalyze the ring‐opening polymerization (ROP) of ε‐caprolactone (ε‐CL) with good activity.     

Green preparation of hollow mesoporous silica nanosphere inside-loaded gold nanoparticles and the catalytic activity

In this work, an active nano-catalyst with gold nanoparticles loaded in hollow mesoporous silica nanospheres (HMSNs/Au) was prepared by a one-pot sol-gel method, in which gold ions were loaded in hollow mesoporous silica spheres followed by sodium alginate reduction. The characterization of the HMSNs/Au were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N₂ adsorption–desorption isotherms (BET). The high catalytic activity of HMSNs/Au, denoted as apparent turn-over frequency (TOF), was detected by UV-Vis spectrophotometer for the catalytic reduction of 4-nitrophenol (74.5 h^?1) and 2-nitrophenol (108.7 h^?1) in the presence of sodium borohydride solution due to the small gold nanoparticles size and overall exposure of active sites. It is expected that this ecofriendly approach to prepare inorganic composited nanoparticles as high active catalysts based on hollow mesoporous materials was a promising platform for loading noble metal nanoparticles.     

Nitrogen-doped graphene supporting PtSn nanoparticles with a tunable microstructure to enhance the activity and stability for ethanol oxidation

In this work, a series of nitrogen-doped graphenes (NGs) were prepared by deriving from pyrolysis of graphite oxide (GO) with urea at different temperatures and high-dispersed PtSn nanoparticles with tunable size were then deposited onto nitrogen-doped graphene (PtSn/NG) by an easy-controlled template-free method. The PtSn/NG and undoped graphene (PtSn/G) were carried out as anode catalysts for the electrooxidation of ethanol. The microstructure and morphology of the synthesized catalysts were characterized by transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. The electrocatalytic performance toward ethanol oxidation was evaluated by cyclic voltammetry and chronoamperometry. It is found that the pyrolysis temperature is an important factor which influenced the contents of nitrogen and functional groups of nitrogen. And then, the functional groups of nitrogen affect the distribution, size, and contents of PtSn nanoparticles. The as-obtained optimal PtSn/NG-600 sample with narrower size distribution and high content of PtSn exhibits higher electrocatalytic activity and stability compared with the other samples, implying the potential application for ethanol fuel cells.     

On‐plate enzyme and inhibition assay of glucose‐6‐phosphate dehydrogenase using thin‐layer chromatography

We performed on‐plate enzyme and inhibition assays of glucose 6‐phosphate dehydrogenase using thin‐layer chromatography. The assays were accomplished based on different retardation factors of the substrates, enzyme, and products. All the necessary steps were integrated on‐plate in one developing process, including substrate/enzyme mixing, reaction starting, and quenching as well as product separation. In order to quantitatively measure the enzyme reaction, the developed plate was then densitometrically evaluated to determine the peak area of the product. Rapid and high‐throughput assays were achieved by loading different substrate spots and/or enzyme (and inhibition) spots in different tracks on the plate. The on‐plate enzyme assay could be finished in a developing time of only 4 min, with good track‐to‐track and plate‐to‐plate repeatability. Moreover, we determined the K_m values of the enzyme reaction and K_i values of the inhibition (Pb²⁺ Cd²⁺ and Cu²⁺ as inhibitors), as well as the corresponding kinetics using the on‐plate assay. Taken together, our method expanded the application of thin‐layer chromatography in enzyme assays, and it could be potentially used in research fields for rapid and quantitative measurement of enzyme activity and inhibition.