Visualization and In Situ Ablation of Intracellular Bacterial Pathogens through Metabolic Labeling

Protected by the host cells, the hidden intracellular bacteria are typically difficult to kill by common antibiotics and cannot be visualized without complex cellular pretreatments. Herein, we successfully developed a bacteria-metabolizable dual-functional probe TPEPy-d -Ala, which is based on d -alanine and a photosensitizer with aggregation-induced emission for fluorescence turn-on imaging of intracellular bacteria in living host cells and photodynamic ablation in situ. Once metabolically incorporated into bacterial peptidoglycan, the intramolecular motions of TPEPy-d -Ala are inhibited, leading to an enhanced fluorescent signal, which allows the clear visualization of the intracellular bacteria. Moreover, TPEPy-d -Ala can effectively ablate the labeled intracellular bacteria in situ owing to covalent ligation to peptidoglycan, yielding a low intracellular minimum inhibitory concentration (MIC) of 20±0.5 μg mL⁻¹, much more efficient than that of a commonly used antibiotic, vancomycin.     

Metal–Organic Gels from Silver Nanoclusters with Aggregation-Induced Emission and Fluorescence-to-Phosphorescence Switching

Luminescent metal nanoclusters (NCs) are emerging as a new class of functional materials that have rich physicochemical properties and wide potential applications. In recent years, it has been found that some metal NCs undergo aggregation-induced emission (AIE) and an interesting fluorescence-to-phosphorescence (F-P) switching in solutions. However, insights of both the AIE and the F-P switching remain largely unknown. Now, gelation of water soluble, atomically precise Ag₉ NCs is achieved by the addition of antisolvent. Self-assembly of Ag₉ NCs into entangled fibers was confirmed, during which AIE was observed together with an F-P switching occurring within a narrow time scale. Structural evaluation indicates the fibers are highly ordered. The self-assembly of Ag₉ NCs and their photoluminescent property are thermally reversible, making the metal–organic gels good candidates for luminescent ratiometric thermometers.     

The influence of grafted functional groups on the adsorption properties of silica

The adsorption properties of silica gel with grafted aminopropyl and guanidinoethanethiol (GET) groups were studied by the techniques of adsorption under static conditions and gas chromatography. It was shown that molecules capable of forming hydrogen bonds are adsorbed on all modified samples more weakly than on the initial silica gel. The grafting of GET radicals on the surface results in a noticiable increase in the dispersion interaction with adsorbed molecules. Calculation of the contributions of molecular groups to the constant of adsorption equilibrium showed that the thermodynamic characteristics of adsorption on aminosilochromes and aminosilicas with a polymeric layer of the modifying agent have similar values. Such adsorbents can be used for investigation of polar compounds, including organic bases. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 452–457, March, 1997.     

负载型CuO—ZnO／γ—Al2O3催化剂抗硫中毒性能的研究

采用XPS、TPR法证明浸渍法制备的CuO-ZnO/Al_2O_3催化剂中的CuO、ZnO和γ-Al_2O_3之间存在强相互作用,Cu量≤7.0wt%,Zn量≤11Wt%时,CuO和ZnO以单分子层分散在γ-Al_2O_3上.催化剂表面Cu和Zn实际含量的比值远小于配制时的比值(Cu/Zn=2),表明ZnO比CuO优先分布在表面.因ZnO比CuO更易和S作用生成ZnS,ZnO在表面的大量存在减少了Cu被S中毒的机率;另外CuO单层分散在Al_2O_3上,还原后生成的Cu~0,由于γ-Al_2O_3的拉电子作用使其处于缺电子状态(CU~(?+)),加上催化剂表面可能有部分CuO和Al_2O_3形成尖晶石,使一部分Cu以Cu~(n+)存在,Cu~((?)+)或Cu~(n+)对S的吸附弱.以上两个原因使负载型铜催化剂具有良好的抗硫中毒性能.     

NSB对油菜某些生理特性及产量的影响

在油菜的蕾苔期、初花期喷施一定浓度的植物生长调节剂萘乙酸、微量元素锶和硼的混合配方,可以促进植物的生长发育和增强花粉的生活力,提高泌蜜量、叶绿素含量和硝酸还原酶的活性,增强植株的根系活力和抗旱性,加快可溶性糖的转移,同时能有效地提高油菜产量。     

双核铂的Pt2（CN）4（CNC4H9）4的发光机制及Pt...Pt间互作用的从头计算研究

利用从头算ＭＰ２方法优化了Ｐｔ（ＣＮ）２（ＣＮＣＨ３）２,Ｐｔ（ＣＮ）２（ＣＮＣＨ３）２－（ＮＣＣＨ３）２．「Ｐｔ（ＣＮ）２．（ＣＮＣＨ３）２」２的在态几何结构,利用单激发的组态相互作用方法（ＣＩＳ）计算了固态和乙氰溶液中标题化合物的发射光谱,并对激发态的几何结构进行了优化,结果表明,基态时,Ｐｔ．．．ＮＣＣＨ３之间的距离较大（０．４０６ｎｍ）,说明溶剂分子与Ｐｔ原子之间存在较小的范德华作用;而激发时,Ｐｔ．．．ＮＣＣＨ３之间的距离减小（０．２５７ｎｍ）,说明此时Ｐｔ．．．ＮＣＣＨ３之间相互作用较强,由于这种作用使乙氰溶液中该物质的发光性质与不考虑溶剂效应时相比差异较大,其发射光谱不可我谱区,固态时,此化合物为直线链状结构,ＭＰ２计算得到：基态时「Ｐｔ（ＣＮ）２（ＣＮＣＨ３）２」２中Ｐｔ．．．Ｐｔ之间的距离为０     

超临界流体萃取仪器的研制

本文报道了以国产原配件为基础，成功地研制了分析规模的超临界流体萃取仪器、并对仪器性能进行了全面考察，仪器性能稳定，重现性良好（ＲＳＤ＜３．１％），定量线性关系可靠，可满足定量萃取的要求。