液膜稳定性的研究

利用单滴法对三种表面活性剂的液膜体系的稳定性进行了研究，重点考察了载体的影响，讨论了介质与表面活性剂，介质与载体，载体与表面活性剂的相互作用对液膜稳定性的影响，并根据膜强度数据，给出了液膜稳定的条件。     

Determination and Differentiation of Two Seemingly Identical Medicinal Herbs by Capillary Electrophoresis with Electrochemical Detection

A high-performance capillary electrophoresis with electrochemical detection (CE-ED) method has been employed for the determination of six bioactive ingredients in traditional Chinese herbs, Herba cepbalanoplosis segeti and Herba cirsii japonici. The effects of several factors such as the acidity and concentration of running buffer, the separation voltage, the applied potential and the injection time on CE-ED were investigated. Under the optimum conditions, the six analytes could be well separated within 21 min in a 75 cm length capillary at the separation voltage of 15 kV in a 50 mmol L^–1 borax running buffer (pH 8.4). A 300 m diameter carbon disk electrode was used as the working electrode positioned carefully opposite the outlet of the capillary in a wall-jet configuration at potential of +950 mV (vs. SCE). Good linear relationship was established between peak current and concentration of analytes over two orders of magnitude with detection limits (S/N=3) ranged from 1.5×10^–7 to 6.0×10^–7 g mL^–1 for all six analytes. This proposed method has been successfully applied for the analysis of traditional Chinese herbs after a relatively simple extraction procedure, further on, for the differentiation of these above two seemingly identical herbs based on their electropherograms or characteristic electrochemical profiles.     

A facile electrochemical synthesis of caffeic acid derivatives in the presence of acetylacetone or methyl acetoacetate in aqueous medium

The anodic oxidation of caffeic acid in the presence of acetylacetone or methyl acetoacetate in aqueous solution has been studied by cyclic voltammetry and controlled-potential electrolysis techniques. The result showed that caffeic acid was oxidized to the corresponding o-benzoquinone, which underwent further Michael-addition with acetylacetone or methyl acetoacetate to produce caffeic acid derivative 3,4-dihydroxy-6-(1-acetylacetone)-yl cinnamic acid 4a or 3,4-dihydroxy-6-(1-acetyl-methylacetate)-yl cinnamic acid 4b.     

The adsorption and dissociation of O2 on Cu low-index surfaces

The extended LEPS of O(2)-Cu single crystal plane systems is constructed by means of 5-MP (the 5-parameter Morse potential). Both the adsorption and dissociation of O(2) on Cu low-index surfaces are investigated with extended LEPS in detail. All critical characteristics of the system that we obtain, such as adsorption geometry, binding energy, eigenvalues for vibration, etc., are in good agreement with the experimental results. Our calculated results suggest there are many differences between O(2)-Cu (110) and O(2)-Pd (110) systems. On a Cu (110) surface, O(2) adsorbs in a tilted configuration and there are two lowest energy dissociation channels along the [001] and [10] directions, respectively. We speculate that the adsorption geometry of O(2) on the metal surfaces relates to the lattice constant of metal. Meanwhile, We use the concepts of the molecular dissociation limit and the surface dissociation distance to analyze again the dissociation mechanism of the O(2) on the low-index surfaces.     

A recyclable fluorous organocatalyst for Diels-Alder reactions

Chiral fluorous imidazolidinone catalyst 2 provides consistently high enantioselectivities in Diels–Alder reactions of dienes and ,β-unsaturated aldehydes. The catalyst can be readily separated from the reaction products by fluorous solid-phase extraction, and recovered in excellent purity for direct reuse.     

Quasienergy formalism for intense field multiphoton ionization of atoms induced by circularly polarized radiation

A practical non-perturbative approach is presented for multiphoton ionization of atoms induced by circularly polarized radiation. By use of co-ordinate rotation transformation and L²-discretization of the atomic continuum, the complex energy spectrum of a stationary quesienergy operator can be located and multiphoton ionization rates determined as a function of time and arbitrary photon intensity. The theory is applied to the two-photon ionization of the H atom in intense fields.     

An unprecedented N-transacylation reaction on 2-acetamido-2-deoxy-α-d-glucopyranosides

An unprecedented N-transacylation reaction on 2-acetamido-2-deoxy-α-d-glucopyranosides was disclosed in the presence of acyl chloride and DMAP under reflux in pyridine.     

A study on postsplenectomy changes of serum tuftsin level using a radioimmunoassay protocol

In this article, postsplenectomy changes of serum tuftsin level were studied on both human subjects and rabbits by using a self-established radioimmunoassay protocol. Antituftsin antibodies were raised in rabbits and roosters.¹²⁵I-tuftsin was prepared through an Iodogen method. The characteristics of the RIA were satisfactory with a detecting range of 0.5–100 ug/ml and the lowest detection limit of 400ng/ml. Serum tuftsin levels of splenectomized subjects were measured and compared with control groups. The serum tuftsin level from 30 postsplenectomy human beings was 406±179 ng/ml ( ± s) while that from a control group of 40 healthy blood donors was 557±256 ng/ml; the serum tuftsin level of 10 postsplenectomy rabbits was found to be 206±75 ng/ml while that of a control group of 10 normal rabbits was 318±96 ng/ml. The results showed that serum tuftsin level decreased markedly after splenectomy.     

全硅MCM-41担载的加氢脱硫催化剂的TPR研究

用TRP技术研究了以全硅MCM-41(Si-MCM-41)和HNO3交换的全硅MCM-41(H-MCM-41)为载体制备的Ni-Mo、Co-Mo和Ni-W加氢脱硫(HDS)催化剂的还原性能，并以0．8(wt)％二苯并噻吩(DBT)的十氢萘溶液为模型化合物，在高压固定床反应器上考察了上述催化剂的加氢脱硫(HDS)反应性能。结果表明，Si-MCM-41经稀HNO3交换后，所担载的Ni-Mo和Ni-W催化剂还原性能、HDS活性和加氢活性有显著变化，但对Co-Mo催化剂影响不大。这说明在Ni-Mo／H-MCM-41和Ni-W／H-MCM-41中可能存在氢溢流现象，DBT的HDS活性与载体表面酸性和氢溢流有关。     

Design, synthesis, and binding affinities of pyrrolinone-based somatostatin mimetics

[structure: see text] Tetrapyrrolinone somatostatin (SRIF) mimetics (cf. 1), based on a heterochiral (D,L-mixed) pyrrolinone scaffold, were designed, synthesized, and evaluated for biological activity. The iterative synthetic sequence, incorporating the requisite functionalized coded and noncoded amino acid side chains, comprised a longest linear synthetic sequence of 23 steps. Binding affinities at two somatostatin receptor subtypes (hsst 4 and 5) reveal micromolar activity, demonstrating that the d,l-mixed pyrrolinone scaffold can be employed to generate functional mimetics of peptide beta-turns.