Zinc nutrition in young Chilean adults

To evaluate the effect of dietary factors on plasma zinc levels, dietary zinc intake was estimated and plasma levels were measured in 37 healthy young adults of low and middle socioeconomic status. Our study included 16 males aged 29 +/- 7 and 21 females aged 26 +/- 6 years. Dietary intake of zinc and protein was determined from a 24-hour dietary recall survey. Plasma zinc was measured by atomic absorption spectrophotometry. Alkaline phosphatase (AP) in plasma was also measured and the weight/height percentage for each subject calculated according to Jelliffe's standards. The average diet was composed of cereals, legumes, eggs, bread and noodles, caloric intake was 2051 +/- 154 kcal/day for men and 1767 +/- 158 (x +/- SD) kcal/day for women. The daily intake of zinc was 8.3 +/- 3.0 mg/day for males, and 9.7 +/- 2.0 mg/day for females. Cereals were the main source of zinc for men, while egg and dairy products were for women. Plasma zinc values were 82 +/- 22 micrograms/dl for men and 94 +/- 19 micrograms/dl for women (p less than 0.01). For the whole group plasma zinc concentration was 89 +/- 21 micrograms/dl. Seven males and two females had low plasma zinc values (70 micrograms/dl or less). Alkaline phosphatase (AP) levels were 110 +/- 10 IU for males and 71 +/- 4 IU for females (p less than 0.001). These values did not correlate with the zinc levels. Average weight/height was 99 +/- 18 for men, and 108 +/- 18 for females. Results indicate that on the average, in our study group plasma zinc levels were within the normal range, although they were significantly lower in men. Dietary intake of zinc was below the recommendations, being higher for women as related to values presented by men. The observed low plasma levels of zinc may be caused by a low intake, and/or poor bioavailability.     

Infrared studies of the interaction of carbon monoxide and dinitrogen with ferrisilicate MFI-type zeolites

Fourier transform IR spectroscopy of CO and N₂, adsorbed at liquid nitrogen temperature, was used to characterize an MFI-type H-FeZSM-5 ferrisilicate which was synthesized with a Si/Fe ratio of 50. Thermal treatment of this material at 773 and 973 K was performed in order to follow formation of extraframework species. On samples fired at 773 K Brønsted acid sites were present which gave an O-H stretching band at 3630 cm^–1. These hydroxyl groups formed adducts with both probe molecules, which were monitored by the corresponding bathochromic shift, . Corresponding values for adsorbed CO and N₂ were = –270 and = – 100, respectively. Increasing the firing temperature up to 973 K led to complete removal of iron from the zeolite framework, and consequent disappearance of Brønsted acidity. In this process, extraframework iron oxide species were formed which were also characterized by IR spectroscopy of the adsorbed probe molecules. Both CO and N₂ gave Lewis-type adducts with coordinatively unsaturated Fe³⁺ ions present in the extraframework material. A comparison is made with results of a previous study on the H-GaZSM-5 isomorph.     

葡聚糖修饰漆酶的制备及其催化特性和稳定性

将经NaIO₄氧化处理的葡聚糖（500×10³）连接在漆酶分子上以提高漆酶在酸性溶液环境中的稳定性。HPLC和SDS-PAGE分析表明葡聚糖修饰漆酶的分子量在200×10³以上。荧光光谱和圆二色性光谱分析表明修饰漆酶保持了天然漆酶的三级和二级结构。酶催化反应显示修饰漆酶与天然漆酶具有类似的底物亲和性和催化活性，而其在酸性条件下的稳定性显著提高。通过葡聚糖修饰使得漆酶在pH 3,50℃下的酶活半衰期从0. 07 h提高到17. 1 h，在含30%（体积）乙腈, pH 3下的酶活半衰期从0. 11 h提高到10. 3 h。在不同pH下测定修饰漆酶在216 nm处的圆二色性光谱，结果显示偶联葡聚糖增强了漆酶分子的结构稳定性，提高了其在高温及有机溶剂存在下的催化活性。     

Study of Ozonated Sunflower Oil Using 1H NMR and Microbiological Analysis

Prior studies have proven that ozonated vegetable oils present a high germicidal power. Ozonation of sunflower oil at different applied ozone dosage was carried out and peroxide and aldehydes indices along with antimicrobial activity were determined. The reaction products were identified using Proton Nuclear Magnetic Resonance Spectroscopy (¹H NMR). The principal signals intensity values were used for following the reaction course between ozone and sunflower oil. The reaction was following up to peroxide index values of 1202 mmol-equi/kg. The intensities of olefinic proton signals decreased with the gradual increase in ozone concentration but without disappearing completely. The Criegee ozonides obtained at 107.1 mg/g of ozone doses were approximately 3.9-fold higher than that at beginning of the reaction. The aldehyde protons were observed as a weak intensity signal in all the spectra. The signals belonging to olefinic protons from hydroperoxides appeared weak and increased with the increase in ozone doses. Signals from other oxygenated groups were assigned. The highest action spectrum of antimicrobial activity was obtained with the higher peroxide index. It was concluded that at higher applied ozone doses, the higher the antimicrobial activity potential of ozonized sunflower oil     

在四氯化碳中合成邻硝基对甲基苯胺的研究

以对甲基苯胺为母体，合成了邻硝基对甲苯胺，产品收率在85％以上，在乙酰化，硝化反应中引入了四氯化碳溶剂，2最佳原料配比为对甲基苯胺；醋酐：硫酸＝1：1．30：1．13。改进后，每mol母体的醋酐用量由3．10mol减少至1．30mol，浓硫酸用量由3．17mol减少至1．13mol，溶剂回收率在95％以上。     

Tocopherol oil concentration in field-grown sunflower is accounted for by oil weight per seed

Tocopherols are natural antioxidants that increase the stability of fat-containing foods and perform important biological activities. Significant variations (389 to 1873 μg g oil⁻¹) in the total tocopherol concentration of sunflower seed oil have been reported. The main objectives of this work were to determine the influence of intercepted photosynthetically active radiation on tocopherol concentration during seed filling and to establish and validate relationships between tocopherol concentration in oil and other quality variables of the seed. Seven sunflower hybrids were grown under good water and nutritional conditions in two similar experiments carried out in two contrasting environments. Treatments were applied to modify the amount of radiation intercepted per plant during seed filling in order to obtain a range in oil yield per plant and its components. Greater per plant intercepted radiation decreased the tocopherol concentration in oil. Tocopherol concentration decreased when oil weight per seed increased. Tocopherol concentration stabilized for oil weight per seed higher than 23 mg oil seed⁻¹. This exponential relationship accounted for 73% of the variability in tocopherol concentration (507 to 1203 μg g oil⁻¹) despite differences in hull type, locations, hybrids, and radiation treatments. The proposed relationship acceptably predicted independent results. Crop management techniques could lead to seeds with greater concentrations of tocopherols.     

磷铝酸盐水泥浆体的抗冻性研究

抗冻性是砼耐久性的重要方面,尤其影响北方地区砼工程的使用寿命。引气能提高砼的抗冻性,但同时又存在气泡的稳定性问题和砼其他性能的受损问题。若能提高砼中水泥浆体的抗冻性,则对提高砼耐久性更有意义。作者从宏观和微观两方面研究了磷铝酸盐水泥浆体的抗冻性,同时与硅酸盐水泥、硫铝酸盐水泥浆体进行了比较;采用压汞测孔方法测试了三种水泥浆体冻融前后的孔结构,并用分形理论分析了各自特征。结果证实:磷铝酸盐水泥具有优越的抗冻融性能,其自身优良的水化特性以及体系的低碱度是良好抗冻性的内在原因。     

From Molecular Clusters to Metal Nanoparticles

Different methods to prepare supported metal nanoparticles of uniform size are discussed. (i) Supported ruthenium particles were generated from Ru and Ru-Fe bimetallic molecular metal carbonyl cluster precursors (MCC). (ii) Gold nanoparticle formation in the supercage of Y zeolite was studied on Au/NaY, Au/HY and Au-Fe/HY system. (iii) Palladium nanoparticles were grown in liquid phase then deposited on an SiO₂ support or they were grown on the support surface in a solid-liquid interfacial layer. The particle size control was more efficient in the latter two cases than in the preparation starting from MCC.     

Modeling and control of Wiener-type processes

We develop a simple relay feedback method to identify Wiener-type nonlinear processes. It separates the identification problem of the nonlinear static function from that of the linear dynamic subsystem to simplify the identification procedure significantly. Owing to the separation, the unmeasurable output of the linear dynamic subsystem can be obtained in a straightforward manner. Then, determining the model structure of the nonlinear static function becomes very simple and the estimates are robust to additive output noises. We can identify the whole activated region of the nonlinear static function as well as the ultimate information of the linear dynamic subsystem from only one relay feedback test. More information on the linear dynamic subsystem can be estimated by well-established linear system identification methods from additional tests. We use a nonlinear control strategy to compensate the nonlinear dynamics of the Wiener process so that the design parameters can be determined by usual tuning rules developed for linear processes and a high control performance can be achievable as in linear processes.     

柴油机废烟气驱动的热管LiBr制冷机的分析

工业过程中的废热排放造成了可用能的损失 ,又造成热污染和环境污染。针对一种利用热管回收废热的LiBr制冷机 ,采用柴油机烟气废热制冷实测后 ,对该系统的实测结果进行了火用分析 ,分析结果表明了这种新型废热LiBr制冷机有效利用了柴油机烟气余热 ,提高了系统的火用效率