镝的钼硅杂多配合物的合成,结构和振动光谱

合成了镝的钼硅杂多配合物K_(10)H_3[Dy(SiMo_(11)O_(39))_2]·20H_2O,用X射线单晶结构分析,确定其空间群为P2_1/n,晶胞参数.结果表明:SiMo_(11)O_(39)~(8-)作为四齿配体与Dy配位,Dy与8个氧原子配位,形成四方反棱柱.K离子的配位数有6、7、8、和94种.讨论了该配合物的振动光谱.     

Computer-Aided Discovery of Potent Broad-Spectrum Vaccine Adjuvants

Adjuvants stimulate the immune system to vigorously respond to a vaccine. While current adjuvants such as aluminum salts and oil-in-water emulsions have been used for decades, they do not generate broad and long-lasting responses in many vaccines. Consequently, more potent adjuvants are needed. Here, using computer-aided molecule design and machine learning, we discovered 2 new, broad-spectrum adjuvants that can boost vaccine responses. Our library containing 46 toll-like receptor (TLR)-targeting agonist ligands were assembled on Au nanoparticles. Comprehensive in vitro, ex vivo and in vivo studies showed both leads promoted dendritic cell activation via multiple TLRs and enhanced antigen presentation to T cells. When used together with tumor-specific antigens to immunize mice against B16-OVA melanoma and 4T1-PD1 breast cancer, both adjuvants unleashed strong immune responses that suppressed tumor growth and lung metastases. Our results show computer-aided design and screening can rapidly uncover potent adjuvants for tackling waning immunity in current vaccines.     

Dissociative Photoionization of m-Xylene

The photoionization and dissociative photoionization of m-xylene (C₈H₁₀) were researched by using synchrotron radiation vacuum ultraviolet (SR-VUV) and supersonic expanding molecular beam reflectron time-of-flight mass spectrometer (RFTOF-MS) system. The photoionization efficiency spectra (PIEs) of parent ion C₈H₁₀⁺ and main fragment ions C₈H₉⁺ and C₇H₇⁺ were observed, and the ionization energy (IE) of m-xylene and appearance energies (AEs) of main fragment ions C₈H₉⁺ and C₇H₇⁺ were determined to be 8.60 ± 0.03 eV, 11.76 ± 0.04 eV and 11.85 ± 0.05 eV, respectively. Structures of reactant, transition states (TSs), intermediates (INTs), and products involved in two dominant dissociation channels were optimized at the B3LYP/6-311++G(d,p) level, and the relative energies were calculated at the G3 level. Based on the results, two major dissociative photoionization channels, C₇H₇⁺+CH₃ and C₈H₉⁺+H were calculated at the B3LYP/6-311++G(d,p) level. On the basis of theoretical and experimental results, the dissociative photoionization mechanisms of m-xylene were proposed. The C–H or C–C bond dissociation and hydrogen migration are the main processes in the dissociation channels of m-xylene cation.

     

高效液相色谱-电感耦合等离子体质谱(ICP-MS)法测定中药材中无机汞、甲基汞、乙基汞

为准确测定中药材中不同形态的汞含量,通过选用人工胃液作为提取液,经水浴加热提取后,以甲醇-乙酸铵为流动相,采用C18反相色谱柱对样品溶液进行分离,最后经电感耦合等离子体质谱(ICP-MS)法测定3种汞形态化合物的含量。建立了中药材中无机汞、甲基汞、乙基汞的高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)法的测定方法,结果表明,3种汞形态化合物在0.5～5 ng/mL范围内均获得良好的线性关系,相关系数均大于0.999。通过加标回收的方法进行准确性评价,加标回收率为75.5%～118%,相对标准偏差RSD为2.4%～9.7%。测定的106批次中药材中,均未检出甲基汞、乙基汞。无机汞检出率为88.7%,合格率为100%。方法能够准确、高效地测定中药材中3种汞形态化合物的含量。106批次中药材中的汞存在形态主要是以无机汞为主。考察的106批次根及根茎类中药材中3种汞形态化合物的含量,积累了基础数据,为中药饮片的质量安全性监管提供技术支撑。     

4,4'-二（羟甲基）联苯的合成

以4,4'-二（氯甲基）联苯为原料,经水解生成苄醇类化合物4,4'-二（羟甲基）联苯。采用¹HNMR, IR, HPLC对产物进行了表征。研究讨论了反应条件、催化剂等因素对产物含量和收率的影响,并且优化了4,4'-二（羟甲基）联苯的合成工艺,提出了可能的催化反应机理。结果表明：聚乙二醇作为催化剂,可与溶液中的阳离子发生络合,增强了亲核试剂的反应活性,提高了反应速率。在优化工艺下反应12 h,粗产品HPLC含量可达97.2%,收率93.9%。     

过渡金属基MOF材料在选择性催化还原氮氧化物中的应用

选择性催化还原(SCR)技术是目前应用最广泛的工业脱硝技术,研发具有优良活性和抗毒化性能的催化剂体系是研究学者关注的重点。过渡金属氧化物和金属有机骨架(MOF)材料因其优良的氧化还原性能在脱硝领域受到了广泛关注和研究,且研究学者发现将过渡金属氧化物与MOF材料结合能够进一步提高催化剂的脱硝活性。本文综述了近年来主要应用于NH₃-SCR反应的系列单过渡金属基MOF脱硝催化剂和复合过渡金属基MOF脱硝催化剂的研究进展,阐述了过渡金属基MOF脱硝催化剂抗水抗硫中毒性能和热稳定性的强化方法,并展望了未来过渡金属基MOF脱硝催化剂的主要研究方向：综合利用不同过渡金属氧化物的特点并结合金属氧化物间的强相互作用,制备得到具有优良脱硝活性、抗水抗硫性能和热稳定性的新型过渡金属基MOF脱硝催化剂,进一步通过实验和仿真模拟相结合制备高效过渡金属基MOF脱硝催化剂以满足工业化需求。     

Ultrasensitive Electrochemical Biosensor for HPV16 Oncogene Based on Y-shaped DNA Catalytic Hairpin Assembly and Template-free DNA Extension Reaction

An ultrasensitive electrochemical biosensor for HPV16 oncogene was explored. Hairpin DNA-1, which can specifically bind with HPV16 oncogene, was fixed on the surface of gold electrode. Two hairpin DNAs underwent catalytic hairpin assembling with hairpin DNA-1 to construct Y-shaped DNA nanostructure, liberating HPV16 oncogene for target recycling. The 3’ terminus of Y-shaped DNA nanostructure was prolonged under the catalysis of terminal deoxynucleotidyl transferase. Methylene blue was adsorbed onto DNA nanostructure to generate characteristic differential pulse voltammetry signal. This signal was increased with the concentration of HPV16 oncogene, and the detection limit of HPV16 oncogene was as low as 0.19 fM.     

A lab-on-disc centrifugal microfluidic system for ultraprecise plasma separation

As the medical community puts forward higher requirements for the speed and convenience of disease diagnosis, point-of-care testing has become a hot research topic to overcome various kinds of healthcare problems. Blood test is considered to be highly sensitive and accurate in clinical diagnosis. However, conventional plasma separation system tends to be bulky and needs professional operations. Moreover, imprecise separation may cause residual biochemical substances such as blood cells to affect the detection results. In this work, to solve these problems, we designed a portable centrifugal microfluidic platform for automatic, rapid and ultraprecise blood separation. The disc consists of multichambers and multi-microchannels where a plasma reservoir and a cell reservoir are connected to each other and collinear with the center of the circle. This structure overcomes the weakness of low separation efficiency (when hematocrit increases) under the traditional blood separation structure (bifurcation structure). As a result, the proposed system achieved 99.9% plasma purity, 99.9% separation efficiency (with a blood hematocrit of 48%) and 32.5% plasma recovery rate in the 50s, which provides a strong guarantee for rapid blood diagnosis and analysis, especially in areas where medical resources are limited.     

Palladium Nanoparticles/Graphdiyne Oxide Nanocomposite with Excellent Peroxidase-like Activity and Its Application for Glutathione Detection

In this study, palladium nanoparticles loaded graphdiyne oxide (Pd/GDYO) nanocomposite were fabricated by in-situ reduction of palladium chloride in the dispersion of GDYO, and characte-rized by Raman spectra, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The synthesized Pd/GDYO was first found to have catalytic activities similar to those of the peroxidase enzyme, which can catalyze the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine(TMB) in the presence of hydrogen peroxide(H₂O₂). Steady-state kinetic studies showed that the catalytic reaction of Pd/GDYO follows a ping-pong mechanism, and Pd/GDYO has a stronger activity to TMB with a Michaelis constant(K_m) value of 5.32×10^-4 mmol/L. Based on the shielding effect of glutathione(GSH) on the Pd/GDYO-H₂O₂-TMB reaction system, a colorimetric detection method for GSH was deve-loped with a wide linear range from 0.1 μmol/L to 40 μmol/L and a limit of detection of 0.1 μmol/L. The method was successfully applied for fast and accurate detection of GSH in injection powder drugs. It was expected that this peroxidase-like Pd/GDYO nano- composite would have wide applications in the fields of biomedicine and environmental chemistry.