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本文研究了不同纳米金属含量对溶胶-凝胶法制备的纳米Fe,Co,Ni/介孔TiO2复合体的饱和磁化强度、剩余磁化强度、矩形比和矫顽力的影响.通过振动样品磁强计对纳米复合分体磁学参量(-7.96×105 A·m-1<H<7.96×105 A·m-1)进行测定;结果表明:纳米金属含量对复合体的磁学参量有着复杂的影响. 相似文献
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Controlled-release furosemide microspheres were prepared with various combinations of Eudragit L: Eudragit RS and Eudragit S: Eudragit RS and release of drug from microspheres containing these polymers in different ratios was studied. A wide range of release rates of drug can obtained by a simple change in the ratio of polymers. An increase in Eudragit RS content of polymer microsphere matrix brought about a decrease in the release rate.
On the other hand, the effect of particle size on the drug release rate from furosemide microspheres was also investigated. The effect of microsphere sizes on release rate depends on the type of Eudragit. The decrease in release rates of small microspheres may be due to agglomerate formation. Dissolution data indicated that the release followed Higuchi's matrix model kinetics. 相似文献
On the other hand, the effect of particle size on the drug release rate from furosemide microspheres was also investigated. The effect of microsphere sizes on release rate depends on the type of Eudragit. The decrease in release rates of small microspheres may be due to agglomerate formation. Dissolution data indicated that the release followed Higuchi's matrix model kinetics. 相似文献
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Marianna Erbano Guilherme Schnell e Schühli élide Pereira dos Santos 《International journal of molecular sciences》2015,16(4):7839-7850
The genetic diversity and population structure of Salvia lachnostachys Benth were assessed. Inter Simple Sequence Repeat (ISSR) molecular markers were used to investigate the restricted distribution of S. lachnostachys in Parana State, Brazil. Leaves of 73 individuals representing three populations were collected. DNA was extracted and submitted to PCR-ISSR amplification with nine tested primers. Genetic diversity parameters were evaluated. Our analysis indicated 95.6% polymorphic loci (stress value 0.02) with a 0.79 average Simpson’s index. The Nei-Li distance dendrogram and principal component analysis largely recovered the geographical origin of each sample. Four major clusters were recognized representing each collected population. Nei’s gene diversity and Shannon’s information index were 0.25 and 0.40 respectively. As is typical for outcrossing herbs, the majority of genetic variation occurred at the population level (81.76%). A high gene flow (Nm = 2.48) was observed with a correspondingly low fixation index. These values were generally similar to previous studies on congeneric species. The results of principal coordinate analysis (PCA) and of arithmetic average (UPGMA) were consistent and all three populations appear distinct as in STRUCTURE analysis. In addition, this analysis indicated a majority intrapopulation genetic variation. Despite the human pressure on natural populations our study found high levels of genetic diversity for S. lachnostachys. This was the first molecular assessment for this endemic species with medicinal proprieties and the results can guide for subsequent bioprospection, breeding programs or conservation actions. 相似文献
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Marianna Erbano Carlos Augusto Ehrenfried Maria Élida Alves Stefanello Élide Pereira Dos Santos 《Microscopy research and technique》2012,75(12):1737-1744
Salvia lachnostachys Benth., Lamiaceae, is a endemic species from southern Brazil. The essential oil of its leaves and flowers is mainly constituted by aliphatic compounds, such as dodecanoic acid, with sesquiterpenes as minor constituents. This work evaluated the morphology, anatomy, microchemistry, and phytochemistry of S. lachnostachys to provide advanced knowledge of Brazilian plants with medicinal potential. Light and scanning electron microscopy techniques were used in the anatomical and microchemical studies. Compounds were isolated by chromatographic techniques, identified by analysis of their NMR spectra and compared with published data. S. lachnostachys can be distinguished from other related species mainly by its petiolate leaves, terminal inflorescence, persistent bracts, and villous‐glandular corolla. The stem and leaves of S. lachnostachys display anatomical characteristics common to the family Lamiaceae. However, this species can be distinguished from other family members by the morphology and the presence of eglandular and glandular trichomes, as well as the organization of the vascular bundles of the petiole. The phytochemical results revealed that S. lacnostachys produces oleanolic and ursolic acids in addition to the diterpene fruticuline A, which is a rare compound, previously found only in Salvia fruticulosa Benth. and S. corrugata Vahl. Ursolic and oleanolic acids are bioactive triterpenes that exhibit antiatherosclerotic, anticancer, antihypertensive, antinflammatory, antileukemic, antimutagenic, antioxidant, antiproliferative, and antiviral activities, and fruticuline A has antibacterial activity. Microsc. Res. Tech. © 2012 Wiley Periodicals, Inc. 相似文献
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Jülide Hazal Türkcan Hüseyin Elçiçek Oğuz Kaan Özdemir 《International Journal of Hydrogen Energy》2021,46(11):7903-7911
Hydrogen production through hydrolysis of sodium borohydride (NaBH4) by using metal catalysts is promising for fuel cell applications. Nickel (Ni) and its alloys are favorable due to their high catalytic activity, relatively low cost and availability. In present study, the effects of temperature, pH, reduction rate and reducing agent concentration, which significantly affect the catalyst performance, were investigated using the response surface methodology (RSM). A mathematical model was derived according to results which were obtained from four-level orthogonal Taguchi L16 (44) experimental design used for the optimization of multiple parameters in the process. From the RSM analyses, that compatible with the predicted experimental results, maximum hydrogen generation rate (HGR) 49.81 L min?1 gcat?1 was obtained temperature of 278.12 K, pH of 5.52, reducing agent concentration of 85.96 NaBH4.water?1 and reduction rate of 6.82 mL min?1. Analysis of variance reveals that both pH and rate of reduction have significant effect than the temperature on the HGR. 相似文献
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Jülide Kıvançlı 《International Journal of Food Properties》2016,19(8):1671-1686
The characteristic volatiles of light, medium, and dark roasted Turkish-style boiled coffee brews were studied by headspace solid-phase micro extraction/gas chromatography-mass spectrometry and sensory flavor profile analysis. Sixty-five volatile compounds, including furans, pyrazines, pyrroles, phenols, pyridines, ketones, oximes, alcohols, aldehydes, thiophenes, benzenes, and terpenes, were isolated from Turkish-style boiled coffee samples. The flavor profile analysis showed Turkish coffee brews as roasted/burnt, spicy, bitter, acidic, sweet, salty, astringent (dry), woody, fermented, earthy, and tobacco-like flavor characteristics. It was concluded that Turkish coffee was rich in furans, pyrazines, pyrroles, and phenols giving its roasted/burnt, spicy, woody, and fermented flavor characteristics. 相似文献
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Modeling of cadmium(II) adsorption on kaolinite-based clays in the absence and presence of humic acid 总被引:2,自引:0,他引:2
Cadmium adsorption on kaolinite-based clays in the absence and presence of humic acid was modeled with the aid of the FITEQL 3.2 computer program using a modified Langmuir approach for capacity calculations. Formation of surface–metal ion and surface–humate–metal ion complexes was assumed using the DLM approach. As Cd(II) adsorption was ionic strength-dependent, the adsorption experiments were carried out in solutions containing two different concentrations of an inert electrolyte (0.1 M and 0.005 M NaClO4). The surface sites responsible for the adsorption were assumed to be the permanent charges, ≡S1OH silanol groups and carboxyl groups having pKa values close to that of the silanol groups, and ≡S2OH aluminol groups and phenol groups with pKa values close to that of the aluminol groups, because the studied clays (partly composed of clay soil) contained organic carbon. Cd2+ ions were assumed to bind to the surface in the form of outer-sphere X22− Cd2+ and inner-sphere ≡SOCd+ monodentate complexes. When humic acid was added, Cd(II) adsorption was modeled using a multi-site binding model by the aid of FITEQL3.2. The fit between model and experimental values was excellent in each case. Since the stability of the ternary surface complexes in the presence of humic acid was higher than that of the corresponding binary surface–cadmium ion complexes, the adsorption vs. pH curves were much steeper (and distinctly S-shaped) compared to the tailed curves observed in binary clay–cadmium ion systems. The clay mineral in the presence of humic acid probably behaved more like a chelating ion-exchanger for heavy metal ions than as a simple inorganic ion exchanger. 相似文献
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试谈县级规划部门的改革和发展 总被引:3,自引:0,他引:3
在我国目前的规划体制中,县级规划部门行政级别低、机构设置混乱、人才不足、经费短缺,导致县级规划部门的职能不能有效发挥,严重制约了城乡规划工作的开展。需完善规划立法,理顺规划体制,规范机构设置,改革财政机制和人才机制,增强规划编制的科学性,建立双重领导监督制度。 相似文献