Total synthesis of tropoloisoquinolines: imerubrine, isoimerubrine, and grandirubrine.

A unified, ready access to the tropoloisoquinoline alkaloids imerubrine (1), grandirubrine (2), and isoimerubrine (3) is delineated and features sequential application of the intramolecular Diels-Alder reaction of an acetylene-tethered oxazole and the [4 + 3] cycloaddition of an oxyallyl. A regioselective synthesis of 1 was achieved by stereo- and regioselective oxidation of an 8-oxabicyclo[3.2.1]oct-6-en-3-one cycloadduct by means of the Moriarty method. Such a post-cycloaddition functionalization complements the synthetic utility of an alpha-alkoxy-substituted oxyallyl so as to broaden the scope of the oxyallyl [4 + 3] cycloaddition reaction.     

Electrochemical quartz crystal microbalance study of R-SNO with immobilization on self-assembled monolayer of [Co(tpy-SH)Cl2]

Au/[Co(tpy-SH)Cl₂] electrode was prepared by self-assembled monolayer (SAM) of Au and then synthesized [Co(tpy-SH)Cl₂] and showed good reproducibility in electrochemical properties. The observed formal potential for Co^2+/3+using this electrode was 0.05 V in phosphate buffer at pH 5.6. A strong desorption peak at 0.5 V was observed for deposited R-SNO. The resistance of solutions with Au/[Co(tpy-SH)Cl₂] and Au/[Co(tpy-SH) (R-SNO)_x] electrodes was similar; however, the larger resistance of electron transfer was observed for Au/[Co(tpy-SH) (R-SNO)_x] electrode that incorporated one R-SNO in an electroactive site. A relative standard deviation for calibration curve (r=0.98) was 8% and a liner response was observed for the concentration from 5.8×10⁻¹ M to 5.8×10⁻⁶ M. Interference from amino acids that do not contain a thiol group was 5% or less.     

甲醇-三氟化硼乙醚混合质子电解质

甲醇和三氟化硼乙醚(BFEE)本身离子电导率很低,向甲醇溶液中加入少量BFEE可以形成良好的质子电解质溶液.随着甲醇中BFEE浓度的变化,溶液的离子电导率具有最大值,达20mS/cm.红外光谱和1HNMR研究表明混合电解质中的主要导电离子为MeOH2+和MeOBF3-.     

Spreader-CDR system for efficient,reproducible, and frugal western blot

Efficient antibody incubation is a vital step for successful western blot. During the incubation, a thin antibody-depleted layer is created around the blotting membrane, which limits antibody binding. Although the conventional batch shaking method is ineffective against it, this layer can be easily disrupted by cyclic draining and replenishing (CDR) of the antibody solution during membrane incubation. Previously, we introduced a closed and rotating cylindrical chamber as a tool to implement CDR for western blots (rCDR). A new open bucket-style chamber was devised for easier operation and the possibility of process automation. Instead of rotation as in rCDR, rocking it back and forth achieved the CDR antibody incubation (R-CDR). The chamber was then equipped with a spreader-rod to facilitate the uniform movement of the antibody solution across the membrane surface. Hence, it was named spreader CDR (S-CDR). Compared to the batch incubation method, both the S-CDR and R-CDR devices produced significantly enhanced signals and developed faster results. There were several additional benefits of using the spreader-rod, which included uniform antibody binding across the membrane, reduced usage of antibodies, and the ability to recover results even from mishandled, creased membranes. The S-CDR device ensures better blots and can be easily implemented in existing western blot protocols.     

Variable grid decomposition for ill-posed interferometric tomography: Comparison of algorithms

An algorithm, termed the variable grid method (VGM), has been developed to provide enhanced reconstruction by interferometric tomography under the ill-posed problems of restricted angular scanning and incomplete projection that frequently arise in flow measurements. The algorithm is based on variable grid decomposition of a field. The performances of the two versions of the VGM are compared to investigate the effects of the redundancy criteria in generating variable grid elements. Performance comparison is also made with a conventional fixed grid method. The testing is conducted through computer simulation of experiments and reconstruction with a known three-dimensional field that has been produced by computational fluid dynamics. The reconstruction through computer simulation demonstrates the superiority of the two VGMs to the conventional method. Both the maximum and average reconstruction errors are reduced appreciably. The VGM version with stricter parameter contro performs best. The technique can reflect spatial information contained in measured data. Thus, improvement is noticeable in the regions with dense scanning of probing rays. These regions are usually of interest in engineering applications.     

Optoelectronic Thresholder for Pattern Recognition with Double Feedback Module

The present paper proposes a modification of a simple optoelectronic architecture (A. Bergeron et al.: Appl. Opt. 33 (1994) 1463) for carrying out optical thresholding operations. The threshold operation is achieved by means of a feedback loop. The setup is modified by inserting an attenuator adapted in each iteration to the total incident energy measured by an intensity detector. The proposed architecture does not need an additional light source, assures translation invariance and does not break the beam propagation path. The adaptive attenuator permits working under different lighting conditions (illumination, partially occluded objects, etc.). This kind of architecture is suitable for an optical pattern recognition task, optical neural network or optical associative memory. Application of the modified thresholder to the recognition task based on an optical correlator is reported.     

On stereochemistry of osmium tetraoxide oxidation of allylic alcohol systems. Empirical rule

An empirical formulation is presented to predict the stereochemistry of major osmylation products of allylic alcohols and their derivatives.     

具有轴对称g,A张量的粉末ESR线型表达式

本文推导了s=1/2, g、A均为轴对称张量并具有相同主轴坐标系的粉末ESR线型表达式, 利用这种表达式计算的曲线能与实验曲线很好地吻合。     

A note on differential operators of infinite order

A sufficient condition for entire functions f and g to be such that the series ∑_m=0^∞f^(m)(0)g^(m)/m! represents an entire function is established; and in that case, the growth of the resulting function is described.