离子淌度质谱结合荧光光谱法研究5-氟尿苷与铜锌超氧化物歧化酶的相互作用

分别利用离子淌度质谱和荧光光谱方法研究了5-氟尿苷（5-Furd）与铜锌超氧化物歧化酶（SOD1）的相互作用.离子淌度质谱研究结果表明,5-Furd能够稳定SOD1构型,减缓其碰撞诱导去折叠;外源荧光光谱方法进一步证明5-Furd可以抑制SOD1的聚集.利用荧光光谱研究了不同温度下5-Furd与SOD1的相互作用,阐明了二者的作用机制、结合常数和结合位点数,并根据热力学函数推断二者的作用力类型为典型的疏水作用.     

Geographic Characterization of Leccinum rugosiceps by Ultraviolet and Infrared Spectral Fusion

Leccinum rugosiceps is an edible mushroom belonging to genus Leccinum of Boletaceae. Its fruiting bodies are richer in nutrients than many vegetables and fruit. The model of support vector machine was established for the discrimination of L. rugosiceps from regions based on rapid and low-cost ultraviolet and infrared spectroscopies. The mid-level data fusion was performed by support vector machine. Compared to a single spectroscopic technique, mid-level data fusion provided higher accuracy by selecting the most significant variance from data matrixes based on partial least squares discriminant analysis. The accuracy of the classification of samples in the calibration and test sets were 85.00 and 94.74%, higher than separate measurements by ultraviolet or infrared spectroscopy. This approach has applications for authentication and quality assessment of L. rugosiceps.     

Characterization of a Stable Adaptive Calibration Model Using Near-Infrared Spectroscopy and Partial Least Squares with a Kalman Filter

The calibration model of near-infrared (NIR) spectra established using the Kalman filter-partial least square (partial least squares combined with a Kalman filter) method can be adapted to outdated equipment, environmental changes, external samples, and other applications. However, the variance of the measurement noise estimation for NIR spectrum measurements cannot be easily obtained using Kalman filter-partial least squares; therefore, the variance in the measurement noise is often assumed to be zero for the Kalman filter-partial least square calibration model, which affects the stability of the model. In this study, the measured input and output data were used effectively, and the gamma test method for estimating the measurement noise variance was used to improve the stability of the Kalman filter-partial least square calibration model. First, an accurate estimation of the measurement noise variance was obtained, and accurate modeling was then performed using Kalman filter-partial least squares. Finally, 600 abandoned drilling fluid samples were used to confirm the validity of the proposed method. The Kalman filter-partial least square and gamma test-Kalman filter-partial least square methods are compared. Testing of external samples 401–600 demonstrated that the stability of the Kalman filter-partial least square model decreased. The root mean square error of the prediction of the Kalman filter-partial least square model was 27.135, which was worse than that of the gamma test-Kalman filter-partial least square model (20.307). The validation results show that the proposed method has better stability in tracking the evolution of the NIR spectrometer’s measurement state.     

Zirconium–Porphyrin‐Based Metal–Organic Framework Hollow Nanotubes for Immobilization of Noble‐Metal Single Atoms

Single atoms immobilized on metal–organic frameworks (MOFs) with unique nanostructures have drawn tremendous attention in the application of catalysis but remain a great challenge. Various single noble‐metal atoms have now been successfully anchored on the well‐defined anchoring sites of the zirconium porphyrin MOF hollow nanotubes, which are probed by aberration‐corrected scanning transmission electron microscopy and synchrotron‐radiation‐based X‐ray absorption fine‐structure spectroscopy. Owing to the hollow structure and excellent photoelectrochemical performance, the HNTM‐Ir/Pt exhibits outstanding catalytic activity in the visible‐light photocatalytic H₂ evolution via water splitting. The single atom immobilized on MOFs with hollow structures are expected to pave the way to expand the potential applications of MOFs.     

稀土改质催化剂对废食用油制备燃料油的影响

利用浸渍法制备稀土改质催化剂,用于废食用油脂催化裂解的裂解气催化改质。考察了催化剂活性组分含量、硅铝比、焙烧温度、改质反应温度对产物组成、烯烃含量及收率的影响。得最佳条件:ZSM-5作为催化剂载体,催化剂活性组分镧稀土含量为6%,催化剂焙烧温度为550℃,改质反应温度为360℃。在最佳条件下催化改质,燃料油烯烃含量降低了34.3%,汽油含量提高了14.36%,轻柴油含量提高了1.67%,重柴油含量下降了6.72%,重油含量下降了2.2%,燃料油总收率提高了7.12%,油品质显著提高。     

高效液相色谱-四极杆串联线性离子阱质谱法测定水产品及饲料中的孔雀石绿、结晶紫及其代谢物

提出了高效液相色谱-四极杆串联线性离子阱质谱法测定水产及饲料中的孔雀石绿、结晶紫及其代谢物(隐色孔雀石绿、隐色结晶紫)的方法。样品经乙腈提取,Agilent XDB C18色谱柱分离,四极杆串联线性离子阱质谱进行检测。以氘代孔雀石绿、氘代隐色孔雀石绿、氘代结晶紫、氘代隐色结晶紫为内标物。4种化合物的线性范围均为0.05~5.0μg·L-1,检出限(3S/N)均为0.5μg·kg-1。以空白样品为基体做加标回收试验,计算得4种化合物的回收率在93.3%~120%之间,相对标准偏差(n=6)在1.4%~18%之间。另外,还采用数据相关采集模式结合增强离子扫描模式对4种化合物进行定性分析,可对试样中4种化合物在定量同时进行定性确证。     

Metal‐Organic Gels Based on Carboxyl‐Functionalized Benzimidazole and Their Stimuli Responsivenesses

Three multi‐responsiveness supramolecular metal‐organic gels (MOGs) have been prepared upon Ba(OAc)₂, CdSO₄·8H₂O and Pb(NO₃)₂ with a simple ligand (G17) based on a carboxyl‐functionalized benzimidazole derivative in alcoholic‐water solutions. The MOGs display the formation of well‐developed nanofibrillar networks composed of intertwined fibers which provide stability to gels structures through coordination, hydrogen bonding and π‐ π interactions characterized by using field emission scanning electron microscopy (FESEM), the fourier transform infrared (FT‐IR) spectroscopy and powder X‐ray diffraction (XRD) techniques. MOG‐1 shows good stimuli responsiveness toward the changes in K₂CrO₄, both MOG‐2 and MOG‐3 do good job toward the changes in Na₂S. Moreover, because these MOGs were formed easily by gelator with some heavy metal ion, such as Cd(II) and Pb(II), it might provide the basis for heavy metal ion capture and removal.     

Effects of Oil on Aqueous Foams: Electrical Conductivity of Foamed Emulsions

Three‐phase foams containing dispersed oils (also called foamed emulsion) are usually encountered in such areas as enhanced oil recovery, food foams, and in foams containing antifoams. The presence of oil causes these complex fluids to exhibit extraordinary properties in contrast to aqueous foams. We experimentally investigated, for the first time, the conductive properties of the foamed emulsions and found that the electrical conductivity increases monotonically with the volumetric liquid fraction, presenting a linear relationship. Combined with the analysis on the foaming capacity and microstructure of this complex fluid, the conductive mechanism is revealed. In these foamed emulsions, the whole conductive network is comprised of two levels of structural hierarchy, which displays a different mechanism from those of the conventional aqueous foams. The lamella of emulsions is taken as primary electrical channel, whereas the secondary electrical channel occurs in the lamella between two bubbles. This conductive behaviour is attributed to the microstructure properties of the foamed emulsions. We believe that such findings are potentially important for a better understanding of the fundamentals of these tri‐phase dispersion systems.     

石墨烯层数测量方法的研究进展

石墨烯具有高导电性、高韧度、高强度、超大比表面积等特点,在电子、航天工业、新能源、新材料等领域有广泛应用。对石墨烯层数测量方法的研究有助于深入理解石墨烯性能与微观结构之间的关系。本文着重阐述了包括光学显微镜、拉曼光谱、原子力显微镜和透射电镜等测量石墨烯层数的方法,同时比较了各种测量方法的优点及局限性,并指出石墨烯层数的测量方法还有待进一步完善。     

柱前衍生化HPLC法测定酵母细胞壁中的甘露聚糖与β-葡聚糖

采用1-苯基-3-甲基-5-吡唑啉酮(PMP)为柱前衍生化试剂,结合反相高效液相色谱法,建立了同时测定酵母细胞壁中甘露聚糖和β-葡聚糖的方法。样品中的多聚糖经盐酸高温水解得到甘露糖和葡萄糖,经PMP衍生后,以0.02 mol/L乙酸铵-乙腈(80.5∶19.5)为流动相等度洗脱,反相C18柱(4.6 mm×250 mm,5μm)分离,紫外检测器(波长250 nm)检测,所测2种单糖的含量通过换算后得到甘露聚糖和β-葡聚糖的含量。结果表明,甘露糖和葡萄糖在10.0~1 000 mg/L质量浓度范围内与对应峰面积呈良好的线性关系,相关系数(r2)大于0.999。样品在28.0~80.0 mg范围内加标水平的平均回收率为88.1%~91.0%,相对标准偏差(RSD)小于3%,甘露糖和葡萄糖的检出限(LOD)分别为0.10 mg/L和0.08 mg/L。该方法灵敏度高、准确性好、实用可靠,适用于酵母细胞壁样品中甘露聚糖和β-葡聚糖含量的分析测定。