新型肝胆显影剂配体—Mebrofenin(莱溴氨乙酸)及其类似物的合成

通过溴化、成酐、氨解等反应,合成了新型肝胆显影剂配体(莱溴氨乙酸)及其四个未见报道的类似物。     

Luminescence properties of Ce-doped ZrO2 phosphors synthesized by combustion method

Zr_1−xCe_xO₂ with x = 0.005, 0.01, 0.02, and 0.03 samples were synthesized using a combustion technique. The X-ray diffraction results revealed that Ce-doped ZrO₂ nanoparticles were in a monoclinic structure up to 1 mol% Ce concentration. The increase in the Ce concentration caused more distortion in the monoclinic structure of zirconia. The samples showed a mixed phase (monoclinic + tetragonal) beyond 1 mol% Ce content. The crystallite size (D) and strain (ε) were calculated from the Williamson–Hall equation. The D decreased from 25 ± 1 to 20 ± 1 nm and ε increased from 0.03 to 0.28% with an increase in Ce concentration. Photoluminescence (PL) spectra of Zr_1−xCe_xO₂ showed emission in the blue region under an excitation wavelength of 290 nm. Zr_0.995Ce_0.005O₂ showed the highest PL intensity with an average lifetime of 0.93 μs, and the PL intensity decreased with the increase in the Ce concentration. Thermoluminescence (TL) glow curves of Zr_1−xCe_xO₂ were measured after gamma irradiation (500 Gy) with a heating rate of 5 K s⁻¹. The TL curve of Zr_0.995Ce_0.005O₂ showed two prominent peaks at 412 K (peak 1) and 600 K (peak 2). The first TL glow peak was shifted towards a higher temperature at 440 K above 1 mol% Ce concentration. Repetitive TL measurements on the same aliquot exhibited excellent repeatability. Kinetic parameters associated with the TL peaks were calculated using the curve fitting method. Peak 1 followed non-first-order kinetics. The value of the activation energy of the 440 K peak was found to be 0.95 ± 0.01 eV for Zr_0.99Ce_0.01O₂. These findings showed that Zr_1−xCe_xO₂ might be used in lighting and radiation dosimeter applications.     

N_2和NH_4~ 培养下粪产碱菌固氮酶铁蛋白的生物合成及特性比较

应用DEAE-纤维素和凝胶柱层析,分别将N_2和NU_1~ (30 mmol/L)培养的粪产碱菌固氮酶铁蛋白(Af2和Af~ 2)分离并提纯52倍,在SDS-PAGE上呈均一状态。Af2的比活性达1540 nmol C_2H_4mg~(-1)protein min~(-1),Af~*2无活性。Af2和Af~*2理化性质基本相同,分子量为64.5 kD;均由2个亚基组成,每个亚基分子量为32.5kD;氨基酸种类相同,总残基数分别为537和553,不含色氨酸;每分子Af2和Af~ 2均含有4个Fe原子和4个酸不稳定S~(2-)原子;UV-vis光谱吸收特征相同;荧光探剂测定结果为:每分于Af2和Af~*2均络合2个分子MgATP或2个分子MgADP。     

草莓果实成熟期间RNA代谢的变化

现已证明,鳄梨和番茄等跃变型果实的成熟涉及基因表达的改变和新蛋白质(酶)的合成(Brady 1987)。但是,关于草莓这类非跃变型果实成熟的生化控制机理却很少报道,它们是否也如同跃变型果实那样与新的核酸和蛋白质合成有关?本实验测定了草莓果实成熟期间poly(A)+RNA含量的变化和poly(A)+RNA的体外翻译活性,目的在于探讨草莓果实的成熟机     

A novel approach for removing an industrial dye 4GL by an Algerian Bentonite

Adsorption processes of 4GL on two different bentonite-based sorbents were compared: i) Sodium-bentonite in the presence of a cationic surfactant CTAMB; ii) organobentonite alone. This latter was prepared by exchanging the inorganic cation of bentonite with a quaternary ammonium cation at 100% of the clay's CEC. Batch adsorption studies were conducted to evaluate the effect of various parameters such as the quaternary ammonium cation (CTAMB) loading, contact time and initial 4GL concentration.From the kinetic study, it is interesting to note that Organobentonite exhibits faster kinetics compared to Na-bentonite/CTAMB system. The comparison between isotherm plots makes clear that the presence of CTAMB in solution changes the 4GL isotherm. Compared to organobentonite, the adsorption capacity is higher when CTAMB was present in solution. In this case, the results of 4GL adsorption by bentonite obey to Langmuir model. While for organobentonite, all models seem to be applicable. The difference between the two methods is confirmed by XRD analysis.The performance shown by Organobentonite and Na-bentonite/CTAMB system was suitable compared to other adsorbents, reflecting a promising future utilization in wastewater treatment.     

Instantaneous blood flow, impedance and elastic properties computed in man from aortic pulse waves

A mathematical model of the pressure-flow relationship in the arterial circulation and its possible use in routine hemodynamics in man are described. The instantaneous blood flow velocity in the ascending aorta can be calculated from two pressure curves simultaneously recorded 5 cm apart. The mechanical aortic input impedance is computed from the recorded pressure and the calculated blood flow velocity curves. Projection of the pulse waves on a time-length plane leads to the determination of the pulse wave velocity and then an estimation of the elastic modulus of the aortic wall.     

铈对黄瓜叶绿体叶绿素蛋白质复合物形成的影响

黄瓜（Ｃｕｃｕｍ ｉｓｓａｔｉｖｕｓＬ．）叶片叶绿体中铈（Ｃｅ）含量随Ｈｏａｇｌａｎｄ 培养液中ＣｅＣｌ３ 浓度的增加而增加。Ｃｅ 对黄瓜叶片Ｃｈｌａ／ｂ 比值的影响与光强度有关,当植株生长在强光下,对照和处理叶片的Ｃｈｌａ／ｂ 比值均为３．０７;但在弱光下对照叶片的Ｃｈｌａ／ｂ 比值为２．７２,而处理叶片为２．８６。这说明只有在弱光下Ｃｅ才对叶片色素的组分有影响,Ｃｅ 使叶片中的Ｃｈｌｂ 略有下降。Ｃｅ能促进叶绿体光系统Ⅰ叶绿素蛋白质复合物及１１０ ｋＤ多肽的形成,并使捕光叶绿素ａ／ｂ 蛋白质复合物及其２７ ｋＤ多肽的含量减少。     

Calculated vibrational properties of semiquinones in the A1 binding site in photosystem I

Time-resolved (P700⁺A₁^? – P700A₁) FTIR difference spectra have been obtained using photosystem I (PSI) particles with several different quinones incorporated into the A₁ protein binding site. Difference spectra were obtained for PSI with unlabeled and ¹⁸O labeled phylloquinone (2-methyl-3-phytyl-1,4-naphthoquinone) and 2-methyl-1,4-naphthaquinone (2MNQ) incorporated, and for PSI with unlabeled 2,3-dimethyl-1,4-naphthoquinone (DMNQ) incorporated. (¹⁸O – ¹⁶O), (2MNQ – PhQ) and (DMNQ – PhQ) FTIR double difference spectra were constructed from the difference spectra. These double difference spectra allow one to more easily distinguish protein and pigment bands in convoluted difference spectra. To further aid in the interpretation of the difference spectra, particularly the spectra associated with the semiquinones, we have used two-layer ONIOM methods to calculate corresponding difference and double difference spectra. In all cases, the experimental and calculated double difference spectra are in excellent agreement. In previous two and three-layer ONIOM calculations it was not possible to adequately simulate multiple difference and double difference spectra. So, the computational approach outlined here is an improvement over previous calculations. It is shown that the calculated spectra can vary depending on the details of the molecular model that is used. Specifically, a molecular model that includes several water molecules that are near the incorporated semiquinones is required.