脂肪胺水溶液吸收CO2的热力学参数的密度泛函理论研究

采用密度泛函理论研究CO₂在脂肪胺水溶液热力学参数．研究的脂肪胺包括烷基胺、链烷醇胺、二胺以及氨基酰胺．在B3LYP/6-311+ G(d,p)水平计算脂肪胺在CO₂气相中的振动频率．通过连续介质模型在HF/6-31G(d)水平计算了溶剂几何优化的标准自由能,评价了CO₂吸收到脂肪胺水溶液过程有关的两个重要参数：酸解离常数和标准焓变二者之间大致呈线性关系．随着胺碱度的提高,CO₂吸收过程释放的热量增加,则胺再生所需的能量增加．     

Orthoproducts and f-representations of archimedean {\ell}-groups

Let G be an archimedean \({\ell}\) -group. By an f-representation of G we mean an orthomorphism-valued group homomorphism S on G for which (Sf)g =  (Sg)f for all \({f, g \in G}\) . We prove that the set \({\mathfrak{Rep}(G)}\) of all f-representations in G is an archimedean \({\ell}\) -group with respect to pointwise addition and ordering. Furthermore, we define an orthoproduct on G to be a bilinear map on G which is an orthomorphism in each variable separately. It turns out that the set \({\mathfrak{Opro}(G)}\) is an archimedean \({\ell}\) -group G with the set \({\mathfrak{Mult}(G)}\) of f-multiplications in G as a positive cone. Moreover, we show that \({\mathfrak{Opro}(G)}\) and \({\mathfrak{Rep}(G)}\) are isomorphic as \({\ell}\) -groups. In spite of that, we get a representation theorem for f-multiplications in an \({\ell}\) -subgroup of an archimedean f-ring R with unit element. This allows us to find an example of an archimedean \({\ell}\) -group with no nontrivial structure of an f-ring and another which cannot be a reduced f-ring.     

Description of phenomenological process during thermal formation of an epoxy system in presence of metal nanoparticles using advanced kinetics analysis

The curing process of diglycidyl ether of bisphenol A (DGEBA)–isophoronediamine (IPDA) system filled with different contents of Fe nanoparticles (nano-Fe) has been investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy analysis in order to understand the effect of nano-Fe. These studies revealed that high percentage of the nanofiller, i.e. 10 %, results in improved epoxy matrix as evidenced by increasing in the reaction heat and conversion degree. Kinetics of DGEBA/IPDA/10 % nano-Fe cure was studied by calorimetry measurements at isothermal mode. Isothermal kinetic parameters, including k ₁, k ₂, m, and n were determined and it was shown that the reaction kinetics could be expressed well by dα/dt = (k ₁ + k ₂ α ^m)(1?α)ⁿ which called Kamal model. The results also showed that the diffusion control does not occur. The excellent fitting Kamal model with experimental data at the end of the isothermal cure process could be mentioned as evidences here. The dispersion of 10 % nano-Fe into epoxy matrix was analyzed by atomic force microscopy observations.     

Probing fibronectin-surface interactions: a multitechnique approach

The development of adhesive as well as antiadhesive surfaces is essential in various biomaterial applications. In this study, we have used a multidisciplinary approach that combines biological and physicochemical methods to progress in our understanding of cell-surface interactions. Four model surfaces have been used to investigate fibronectin (Fn) adsorption and the subsequent morphology and adhesion of preosteoblasts. Such experimental conditions lead us to distinguish between anti- and proadhesive substrata. Our results indicate that Fn is not able to induce cell adhesion on antiadhesive materials. On adhesive substrata, Fn did not increase the number of adherent cells but favored their spreading. This work also examined Fn-surface interactions using ELISA immunoassays, fluorescent labeling of Fn, and force spectroscopy with Fn-modified tips. The results provided clear evidence of the advantages and limitations of each technique. All of the techniques confirmed the important adsorption of Fn on proadhesive surfaces for cells. By contrast, antiadhesive substrata for cells avoided Fn adsorption. Furthermore, ELISA experiments enabled us to verify the accessibility of cell binding sites to adsorbed Fn molecules.     

Purification of pediocin PA-1 by immunoaffinity chromatography

A one-step purification procedure for purifying pediocin PA-1, a class IIa bacteriocin produced by Pediococcus acidilactici UL5, was developed based on column immunoaffinity chromatography with specific antipediocin PA-1 polyclonal antibodies coupled to cyanogen bromide-activated SepharoseTM. About 13.3 microg/mL purified pediocin PA-1 was obtained from 15 mL P. acidilactici UL5 culture supernatant, as measured by enzyme-linked immunosorbent assay. The specific activity and average recovery of the eluted pediocin PA-1 were about 6602 AU/mg and 53.3%, respectively. This is the first report of successful purification of pediocin PA-1 by immunoaffinity using pediocin PA-1-specific polyclonal antibodies.     

Determination of etofibrate, fenofibrate, and atorvastatin in pharmaceutical preparations and plasma using differential pulse polarographic and square wave voltammetric techniques

Etofibrate, fenofibrate, and atorvastatin were determined in their pharmaceutical preparations and human plasma using differential pulse polarographic and square wave voltammetric techniques by reduction at a dropping-mercury working electrode versus Ag/AgCl reference electrode. The reversibility of the electrode reactions was tested using cyclic voltammetry, and they were found to be irreversible reduction reactions. Optimum conditions such as pH, scan rate, and pulse amplitude were studied, and validation of the proposed methods was performed. The proposed methods proved to be accurate, precise, robust, and specific for determination of the 3 drugs. The relative standard deviation values were <2%, indicating that these methods are precise. Limits of detection and quantitation were in the ranges of 0.037-0.21 and 0.12-0.71 microg/mL, respectively, indicating high sensitivity.     

Synthesis and anti‐HIV activity of new 2‐thiolumazine and 2‐thiouracil metal complexes

A series of new Cu(II), Pt(II), VO(II), Fe(II), and Co(II) complexes ( 1‐‐5 ) with 3‐methyl‐6,7‐diphenyllumazine are described. Similarly, complexes from 2‐thiouracil with Cu(II) ( 6,7 ) and Pt(II) ( 8 ) have been prepared and characterized by spectroscopic methods. All the complexes were assayed for their anti‐HIV‐1 and HIV‐2 activity by examination of their inhibition of HIV‐induced cytopathogenicity in MT‐4 cells. Compound 3 was found to be the most active inhibitor against HIV‐2 in cell culture (EC₅₀ = >18.9 μ g/mL, selectivity index (SI) = 3), which provided a good lead for further optimization. Compounds 6 and 7 exhibited some activity (EC₅₀ = >7.12 μ g/mL and >2.23 μ g/mL) against HIV‐1 and HIV‐2, but no selectivity was observed (SI <1). © 2010 Wiley Periodicals, Inc. Heteroatom Chem 22:44–50, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20654     

Synthesis of Cyclic Polyamines by Enzymatic Generation of an Amino Aldehyde In Situ

Multifunctional polycationic polyamines, for example, used in drug and gene delivery, have product range limitations in their synthesis methods. Here, we synthesize a polyamine by forming a self‐assembling amino aldehyde from the corresponding amino alcohol with horse liver alcohol dehydrogenase (HLADH), followed by reduction. Circular polyamines were synthesized from 3‐amino‐propan‐1‐ol as starting material, analogous to cyclic polyamines formed from azetidin. The product had an isolated yield of 89.7% or 15.3 g L⁻¹. The predicted range of possible polyamine products by this method is broad since many amino alcohols are putative substrates for HLADH. The enzyme also had activity for 2‐amino‐propan‐1‐ol and 2‐amino‐2‐phenyl‐ethanol, for which the enantioselectivity was 330 (S) and 32 (R), respectively.     

Fluorimetric Determination of Cerium(IV) with Ascorbic Acid

A simple, sensitive, and selective method for the determination of cerium(IV), based on the oxidative reaction between cerium(IV) and ascorbic acid, has been described. The fluorescence comes from Ce(III) at λ_excitation 298 nm and λ_emission 358 nm, which, in turn, is obtained from the oxidation of ascorbic acid by Ce(IV) in the presence of sulfuric acid. The optimum conditions such as concentrations of ascorbic acid, sulfuric acid media and pH of the buffer solution were investigated. The fluorescent intensity of the system is linear over the range 0.0531 μg/ml to 0.3322 mg/ml Ce(IV) and detection limit and correlation coefficient are 0.0145 μg/ml and R=0.99987,respectively.