HIRFL-CSR外靶装置上的放射性束实验数据分析方法研究

开发了HIRFL-CSR外靶实验装置的大型数据分析程序(ANAETF)，并成功应用于核物理实验数据分析。详细阐述了该程序中的数据分析流程、漂移室寻迹算法、粒子鉴别方法和反应截面提取技术。利用本程序分析了240 MeV/u能量下12C次级束流打碳靶的实验数据，实现了清楚的碳和硼剩余核的粒子鉴别，总探测效率达到 ~90%，本工作提取的反应截面与已有的实验结果符合较好。     

Disinfection of Cariogenic Pathogens in Planktonic Lifestyle,Biofilm and Carious Dentine with Antimicrobial Photodynamic Therapy

Antimicrobial photodynamic therapy (aPDT) has been recommended for clinical application. Its antibacterial effect on bacteria remained in dentinal tubule was seldom investigated. Here, we evaluated the antibacterial effects of aPDT on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) in planktonic lifestyle, biofilm and carious dentine. Mono-species biofilms or dentinal caries formed on human dentine slices or slabs. Bacterial suspension, biofilms and dentine caries were treated with 0.1 mg mL⁻¹ toluidine Blue O followed by irradiation with a light emission diode (λ − 635 ± 10 nm; 500 mW; 31.5 J cm⁻²; 60 s) and 0.12% chlorhexidine (CHX), respectively. Residual bacteria were determined by microbial culture analysis and scanning electron microscopy (SEM). One-way analysis of variance (ANOVA) was performed to detect the significance of the variables. Both treatments significantly reduced the number of L. acidophilus in planktonic state, biofilm and carious dentine (P < 0.05). For S. mutans, CHX was only bactericidal against suspension (P < 0.05), while aPDT was effective on both suspension and biofilm (P < 0.05) while not for dentin caries (P > 0.05). Under the experimental conditions assessed, aPDT could be an alternative disinfection method for superficial layer of caries cavity. Its disinfection on bacteria in dentinal tubule of deep layer was deficient.     

Chitosan hydrogel,as a biological macromolecule-based drug delivery system for exosomes and microvesicles in regenerative medicine: a mini review

Cellulose - Extracellular vesicles are membrane-packed entities that are involved in various physiological and pathological processes. Recently, the role of exosomes and microvesicles in...     

Turn-on Circularly Polarized Luminescence in Chiral Indium Chlorides by 5s2 Metal Centers

Introducing chirality into the metal-halide hybrids has enabled many emerging properties including chiroptical activity, spin-dependent transport, and ferroelectricity. However, most of the chiral metal-halide hybrids to date are non-emissive, and the underlying mechanism remains elusive. Here, we show a new strategy to turn on the circularly polarized luminescence (CPL) in chiral metal-halide hybrids. We demonstrate that alloying Sb³⁺ into chiral indium-chloride hybrids dramatically increases the photoluminescence quantum yield in two new series of chiral indium-antimony chlorides. These materials exhibit strong CPL signals with tunable energy and a high dissymmetry factor up to 1.5×10⁻². Mechanistic studies reveal that the emission originates from the self-trapped excitons centered in 5s² Sb³⁺. Moreover, near-ultraviolet pumped white light is demonstrated with a polarization up to 6.0 %. Our work demonstrates new strategies towards highly luminescent chiral metal-halide hybrids.     

Tandem Guest-Host-Receptor Recognitions Precisely Guide Ciprofloxacin to Eliminate Intracellular Staphylococcus aureus

Staphylococcus aureus (S. aureus) is able to hide within host cells to escape immune clearance and antibiotic action, causing life-threatening infections. To boost the therapeutic efficacy of antibiotics, new intracellular delivery approaches are urgently needed. Herein, by rational design of an adamantane (Ada)-containing antibiotic-peptide precursor Ada-Gly-Tyr-Val-Ala-Asp-Cys(StBu)-Lys(Ciprofloxacin)-CBT ( Cip-CBT-Ada ), we propose a strategy of tandem guest-host-receptor recognitions to precisely guide ciprofloxacin to eliminate intracellular S. aureus. Via guest-host recognition, Cip-CBT-Ada is decorated with a β-cyclodextrin-heptamannoside ( CD-M ) derivative to yield Cip-CBT-Ada/CD-M , which is able to target mannose receptor-overexpressing macrophages via multivalent ligand-receptor recognition. After uptake, Cip-CBT-Ada/CD-M undergoes caspase-1 (an overexpressed enzyme during S. aureus infection)-initiated CBT-Cys click reaction to self-assemble into ciprofloxacin nanoparticle Nano-Cip . In vitro and in vivo experiments demonstrate that, compared with ciprofloxacin or Cip-CBT-Ada , Cip-CBT-Ada/CD-M shows superior intracellular bacteria elimination and inflammation alleviation efficiency in S. aureus-infected RAW264.7 cells and mouse infection models, respectively. This work provides a supramolecular platform of tandem guest-host-receptor recognitions to precisely guide antibiotics to eliminate intracellular S. aureus infection efficiently.     

Efficient Visible-Light-Activated Ultra-Long Room-Temperature Phosphorescence Triggered by Multi-Esterification

The development of ultra-long room-temperature phosphorescence (UL-RTP) in processable amorphous organic materials is highly desirable for applications in flexible displays, anti-counterfeiting, and bio-imaging. However, achieving efficient UL-RTP from amorphous materials remains a challenging task, especially with activation by visible light and a bright afterglow. Here we report a general and rational molecular-design strategy to enable efficient visible-light-excited UL-RTP by multi-esterification of a rigid large-plane phosphorescence core. Notably, multi-esterification minimizes the aggregation-induced quenching and accomplishes a ′four birds with one stone′ possibility in the generation and radiation process of UL-RTP: i) shifting the excitation from ultraviolet light to blue-light through enhancing the transition dipole moment of low-lying singlet-states, ii) facilitating the intersystem crossing process through the incorporation of lone-pair electrons, iii) boosting the decay process of long-lived triplet excitons resulting from a significantly increased transition dipole moment, and iv) reducing the intrinsic triplet nonradiative decay by substitution of high-frequency vibrating hydrogen atoms. All these factors synergistically contribute to the most efficient and stable visible-light-stimulated UL-RTP (lifetime up to 2.01 s and efficiency up to 35.4 % upon excitation at 450 nm) in flexible films using multi-esterified coronene, which allows high-tech applications in single-component time-delayed white light-emitting diodes and information technology based on flashlight-activated afterglow encryption.     

藤黄酸重排反应产物研究

藤黄酸能显著抑制多种人类肿瘤细胞的增殖,在酸性环境中易发生重排反应,其重排产物对肿瘤细胞也具有很强的抑制作用.通过波谱技术确定了两个藤黄酸的重排反应产物的结构并归属了其波谱数据.细胞毒活性测试显示,两个重排产物对A549,HCT116和MDA-MB-231显示很强的抑制作用.     

微加速度传感器的结构刚度分析新法

微传感器结构刚度是优化传感器结构尺寸、研究传感器动态响应特性的一个重要参数．目前多采用有限元分析获取这一参数,但该方法难于给出一个物理思想比较明确的解析表达式．针对自主开发设计的一种具有复杂微结构的加速度传感器,提出综合运用力法和能量法原理求解其主轴刚度,并通过仿真分析验证了理论推导．理论计算与仿真分析的结果有较好的一致性．该方法可推广应用于具有对称、静不定微结构的加速度传感器的刚度分析．     

Using block designs in crossing number bounds

The crossing number $\mathrm{\text{CR}}\left(G\right)$ of a graph $G=\left(V,E\right)$ is the smallest number of edge crossings over all drawings of $G$ in the plane. For any $k\ge 1$, the $k$‐planar crossing number of $G,{\mathrm{\text{CR}}}_k\left(G\right)$, is defined as the minimum of $\text{CR}\left(G_1\right)+\text{CR}\left(G_2\right)+?+\text{CR}\left(G_k\right)$ over all graphs $G_1,G_2,\dots ,G_k$ with ${\cup }_{i=1}^k{G}_i=G$. Pach et al [Comput. Geom.: Theory Appl. 68 (2018), pp. 2–6] showed that for every $k\ge 1$, we have ${\text{CR}}_k\left(G\right)\le (2/k^2?1/k^3)\text{CR}\left(G\right)$ and that this bound does not remain true if we replace the constant $2/k^2?1/k^3$ by any number smaller than $1/k^2$. We improve the upper bound to $(1/k^2)\left(1+o\left(1\right)\right)$ as $k\to \infty$. For the class of bipartite graphs, we show that the best constant is exactly $1/k^2$ for every $k$. The results extend to the rectilinear variant of the $k$‐planar crossing number.     

A Terbium Metal–Organic Framework for Highly Selective and Sensitive Luminescence Sensing of Hg2+ Ions in Aqueous Solution

A series of isomorphic lanthanide metal–organic frameworks (MOFs) Ln(TATAB)?(DMF)₄(H₂O)(MeOH)_0.5 (LnTATAB, Ln=Eu, Tb, Sm, Dy, Gd; H₃TATAB=4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoic acid) have been solvothermally synthesized and structurally characterized. Among these MOFs, TbTATAB exhibits good water stability and a high fluorescence quantum yield. Because mercury ions (Hg²⁺) have a high affinity to nitrogen atoms, and the space between multiple nitrogen atoms from triazine and imino groups is suitable for interacting with Hg²⁺ ions, TbTATAB shows highly selective and sensitive detection of Hg²⁺ in aqueous solution with a detection limit of 4.4 nm . Furthermore, it was successfully applied to detect Hg²⁺ ions in natural water samples.