Optimization of the irradiation power in chemical exchange dependent saturation transfer experiments

In chemical exchange dependent saturation transfer imaging experiments, exchangeable solute protons are saturated and the transfer of saturation to water is subsequently detected. When the applied irradiation power is comparable to the resonance frequency difference between the water protons and saturated solute protons, the proton transfer (PT) efficiency is reduced due to concomitant direct saturation effects. In this study, the PT process is modeled using a two-pool system. An empirical general proton transfer ratio (PTR) equation for arbitrary RF irradiation power is derived, and its optimal power to maximize the PTR is analyzed. The results are confirmed experimentally on 4.7 T using a poly-L-lysine solution. The theory provides a useful tool for optimizing the irradiation power of the PT sequences in the presence of direct saturation effects.     

The unstable behavior of cellular premixed flames induced by intrinsic instability

The unstable behavior of cellular premixed flames induced by intrinsic instability is studied by two-dimensional unsteady calculations of reactive flows. In the present numerical simulation, the compressible Navier–Stokes equation including a one-step irreversible chemical reaction is employed. We consider two basic types of phenomena to account for the intrinsic instability of premixed flames, i.e., hydrodynamic and diffusive-thermal effects. The hydrodynamic effect is caused by the thermal expansion through the flame front; the diffusive-thermal effect is caused by the preferential diffusion of mass versus heat. A disturbance with several wavelength components is superimposed on a planar flame, and the formation of a cellular flame induced by hydrodynamic and diffusive-thermal effects is numerically simulated. After the cellular-flame formation, the combination and division of cells are observed. The behavior of cellular-flame fronts becomes more unstable when the Lewis number is lower than unity, since the diffusive-thermal effect has a great influence on the unstable behavior. The cell size changes with time, and its average is greater than the critical wavelength and becomes smaller by decreasing the Lewis number. The flame velocity of cellular flames depends strongly on the length of computational domain in the direction tangential to the flame front. As the length of computational domain increases, the flame velocity becomes larger. This is because the long-wavelength components of disturbances play an important role in the shape of cellular flames, i.e., in the flame-surface area.     

应用FTIR直接测定法鉴定大豆的品种

利用傅里叶变换红外光谱(FTIR)法测定了8个不同大豆品种的子叶及外表皮的红外光谱,对他们的红外光谱进行了分析,并对其吸收峰进行了归属。通过对各谱图的比较分析发现,不同的大豆品种的红外吸收峰形及峰强有所区别。结果表明： 不同的大豆品种的FTIR有明显的差别,特别是1 800～1 200 cm-1范围内有较大的差异,它反映的主要是蛋白质分子的酰胺Ⅰ带及酰胺Ⅱ带附近,这可能是源于基因的差异。因此FTIR法可用于不同大豆品种的鉴别。     

X射线衍射光谱和X光电子能谱研究直接甲醇燃料电池阳极催化剂

利用Ｘ射线衍射光谱和Ｘ光电子能谱研究了甲醇电催化氧化的Ｐｔ－Ｍｏ／Ｃ催化剂,发现该内化剂主要以０价态的Ｐｔ和氧化态的Ｍｏ存在,分析了甲醇在该催化剂的活化机理。     

Data for scaling-up hydrothermal waste water treatment process

Abstract

Hydrothermal oxidation of wastes is developed as an alternative technique in order to limit the toxic end-product formation, the waste volume and the energy supply. We are now working on the transfer of this technology, and so on the determination of data for scaling-up the hydrothermal oxidation process. The main data concern the knowledge of reactive pathway, the determination of reaction kinetic and thermal parameter. Kinetic and thermal data have been determined for the hydrothermal oxidation of acetic acid as well as the reactive pathway of hydrothermal oxidation of a C, H, O, N compound, the fenuron (C₆H₅-NH-CO-N(CH₃)₂).     

Numerical study of a stochastic particle algorithm solving a multidimensional population balance model for high shear granulation

This paper is concerned with computational aspects of a multidimensional population balance model of a wet granulation process. Wet granulation is a manufacturing method to form composite particles, granules, from small particles and binders. A detailed numerical study of a stochastic particle algorithm for the solution of a five-dimensional population balance model for wet granulation is presented. Each particle consists of two types of solids (containing pores) and of external and internal liquid (located in the pores). Several transformations of particles are considered, including coalescence, compaction and breakage. A convergence study is performed with respect to the parameter that determines the number of numerical particles. Averaged properties of the system are computed. In addition, the ensemble is subdivided into practically relevant size classes and analysed with respect to the amount of mass and the particle porosity in each class. These results illustrate the importance of the multidimensional approach. Finally, the kinetic equation corresponding to the stochastic model is discussed.     

High-intensity ultrasonication impact on the chlorothalonil fungicide and its reduction pathway in spinach juice

Among different novel technologies, sonochemistry is a sustainable emerging technology for food processing, preservation, and pesticide removal. The study aimed to probe the impact of high-intensity ultrasonication on chlorothalonil fungicide degradation, reduction pathway, and bioactive availability of spinach juice. The chlorothalonil fungicide-immersed spinach juice was treated with sonication at 360 W, 480 W, and 600 W, 40 kHz, for 30 and 40 min at 30 ± 1 °C. The highest reduction of chlorothalonil fungicide residues was observed at 40 min sonication at 600 W. HPLC-MS (high-performance liquid chromatography-mass spectroscopy) analysis revealed the degradation pathway of chlorothalonil and the formation of m-phthalonitrile, 3-cyno-2,4,5,6-tetrachlorobenamide, 4-dichloroisophthalonitrile, trichloroisophtalonitrile, 4-hydoxychlorothalonil, and 2,3,4,6-tetrachlorochlorobenzonitrile as degradation products. High-intensity sonication treatments also significantly increased the bioavailability of phenolic, chlorophyll, and anthocyanins and the antioxidant activity of spinach juice. Our results proposed that sonication technology has excellent potential in degrading pesticides through free radical reactions formation and pyrolysis. Considering future perspectives, ultrasonication could be employed industrially to reduce pesticide residues from agricultural products and enhance the quality of spinach juice.     

固定漆酶聚苯胺-CoC2O4纳米复合物修饰电极的直接电化学

采用循环伏安法、微分脉冲伏安法、交流阻抗谱以及计时电流法等电化学方法,结合红外光谱、紫外-可见分光光度法、原子力显微镜、透射电子显微镜以及原子吸收光谱等辅助手段,表征了固定漆酶的聚苯胺-草酸钴纳米复合物的化学组成、结构和形貌,测试了纳米复合物固酶前后的导电性能的变化,研究了纳米复合物修饰电极上固定漆酶的直接电化学行为,评估了该电极的催化氧还原效能以及作为电化学传感器检测氧分子的性能。实验结果表明该电极在不含电子介体的溶液中以酶活性中心T2作为首要电子受体,将得到电子传递给化学吸附的氧气使其被电还原,其表观电子迁移速率为0.017 s~(-1),且具有良好的催化氧还原性能(氧还原起始电位:460 m V vs NHE,转化氧分子为水的表观速率常数为2.6×10-4 s~(-1)),酶电催化氧还原为水分子步骤为反应的速控步。该电极作为电化学传感器对氧具有极低检测限(0.20μmol·L~(-1)),宽线性响应范围(0.4~7.5μmol·L~(-1))以及对底物高亲和力(KM=122.4μmol·L~(-1))等优势。     

Direct Blue 71 staining as a destaining‐free alternative loading control method for Western blotting

In Western blotting, a suitable loading control is indispensable for correcting errors in the total amount of loaded protein. Immunodetection of housekeeping proteins and total protein staining have traditionally been used as loading control methods. Direct Blue 71 (DB71) staining—a novel, sensitive, dye‐binding staining method compatible with immunodetection—may offer advantages over these traditional loading control methods. Three common neuroscientific samples (human plasma, human oligodendrocytes, and rat brain) were employed to assess DB71 staining as a loading control method for Western blotting. DB71, CBB, one traditional housekeeping protein, and one protein of interest were comparatively assessed for reliability and repeatability and linear dynamic range over 2.5–40 μg of protein loaded. DB71's effect on the reliability and repeatability and linear dynamic range of immunoreaction were also assessed. Across all three sample types, DB71 was either equivalent or superior to CBB and housekeeping protein‐based methods in terms of reliability and repeatability and linear dynamic range. Across all three sample types, DB71 staining did not impair the reliability and repeatability or linear dynamic range of immunoreaction. Our results demonstrate that the DB71 staining can be used as a destaining‐free alternative loading control method for Western blotting.     

4-Ketozeinoxanthin,a novel carotenoid produced in Escherichia coli through metabolic engineering using carotenogenic genes of bacterium and liverwort

In order to produce a novel keto-carotenoid in Escherichia coli, we introduced the marine bacterial carotenoid ketolase gene (crtW) into pathway-engineered E. coli producing carotenoids of plant origin, which carried the lycopene biosynthesis genes (crtE, crtB, and crtI) from soil bacterium Pantoea ananatis and the liverwort Marchantia polymorpha genes that encode lycopene β-cyclase (MpLCYb), lycopene ε-cyclase (MpLCYe), and β-carotenoid hydroxylase (MpBHY). A novel keto-carotenoid (1) was produced by these carotenoid biosynthesis genes in E. coli along with α-echinenone, adonirubin, and adonixanthin. The structure of 1 was determined as (3S,6′R)-3-hydroxy-β,ε-caroten-4-one based on Uv–vis, MS, ¹H NMR, and CD spectral data. This compound was named 4-ketozeinoxanthin and showed anti-tumor-promoting activity.