Krasnoselskii type fixed point theorems and applications

In this paper, we establish two fixed point theorems of Krasnoselskii type for the sum of , where is a compact operator and may not be injective. Our results extend previous ones. As an application, we apply such results to obtain some existence results of periodic solutions for delay integral equations and then give three instructive examples.

     

Sulfonylamidine-substituted derivatives of avibactam: Synthesis and antibacterial activity

Avibactam is a clinically approved non-β-lactam based β-lactamase inhibitor. Derivatization of this scaffold with improved inhibition profile is the demand of the day to cope with the future challenges. We successfully synthesized new derivatives of avibactam containing sulfonylamidine moieties at C2 position of the diazabicyclooctane ring. We tested in vitro antibacterial activities of newly synthesized compounds against 10 bacterial strains expressing variable β-lactamases. All compounds did not exhibit antimicrobial profile when assayed individually; however, all compounds minimized the MIC value of the imipenem in combination. Compound 5l proved most potent against all 10 bacterial strains, and showed improved inhibition against six bacterial strains as compared with the control inhibitor, relebactam. The compound 5l may be a lead hit for future development.     

Mutlhews-Sumner定理的证明

本文证明了：若Ｇ是２连通无爪图且δ（Ｇ）≥ｎ－２３,则Ｇ是Ｈａｍｉｌｔｏｎ图     

Study of the generalization of regularized long-wave equation

Nonlinear Dynamics - A generalization of the regularized long-wave equation is considered, and the existences of smooth soliton, peakon, and periodic solutions are established via the complete...     

步进累加方法的实践

本文由理论与实验证明步进累加方法本质上是一种狭带的带通滤波的选择接收方法。其线型为类sinc函数。累加的结果与累加次数有关。对单脉冲后步进累加在一定次数以后即趋近饱和。对类回波的接收则出现极大值。只有在弱耦合体系中且offset选择在化学位移处才能得到所谓化学位移滤波。最后讨论实验条件及应用例子。     

系数倍率和卡尔曼滤波紫外分光光度法同时测定发洗剂中的苯酚、间苯二酚和水杨酸

用系数倍率和卡尔曼滤波紫外分光光度法同时测定发洗剂中苯酚、间苯二酚、水杨酸的含量，苯酚、间苯二酚、水杨酸的线性回归方程分别为：A=0．00546 0．01762X，r=0.9999；A=0．00245 0.01606X，r=0．9999；A=-0.00748 0.02491X．r=0．9999。回收率分别为97．8％～102.3％、99．9％～102．3％、99．3％～103．2％。     

二烷基磷（膦）酸钠盐萃取体系的相行为

用二烷基磷（膦）酸钠盐ＮａＡ作为阴离子表面活性剂，测定了ＮａＡ－醇－油－水体系Ｗ／Ｏ型微乳液中水的增溶量，用类三元相 图单相微乳区，测定了ＮａＤＴＭＰＰ－ＨＤＴＭＰＰ－煤油－水（含Ｎａ２ＳＯ４）体系相的变化，并讨论了溶剂、醇、温度、含盐量等对相行为的影响。     

Enantioselective aerobic oxidative cross-dehydrogenative coupling of glycine derivatives with ketones and aldehydes via cooperative photoredox catalysis and organocatalysis

The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective aerobic oxidative cross-dehydrogenative coupling between glycine derivatives and simple ketones or aldehydes, which provides an efficient approach for the rapid synthesis of enantiopure unnatural α-alkyl α-amino acid derivatives in good yield with excellent diastereo- (up to >99 : 1) and enantioselectivities (up to 97% ee). This process includes the direct photoinduced oxidation of glycine derivatives to an imine intermediate, followed by the asymmetric Mannich-type reaction with an enamine intermediate generated in situ from a ketone or aldehyde and a chiral secondary amine organocatalyst. This mild method allows the direct formation of a C–C bond with simultaneous installation of two new stereocenters without wasteful removal of functional groups.

A visible-light-induced enantioselective aerobic oxidative cross-dehydrogenative coupling between glycine derivatives and simple ketones or aldehydes is achieved.     

Click and Release: A Chemical Strategy toward Developing Gasotransmitter Prodrugs by Using an Intramolecular Diels–Alder Reaction

Prodrug strategies have been proven to be a very effective way of addressing delivery problems. Much of the chemistry in prodrug development relies on the ability to mask an appropriate functional group, which can be removed under appropriate conditions. However, developing organic prodrugs of gasotransmitters represent unique challenges. This is especially true with carbon monoxide, which does not have an easy “handle” for bioreversible derivatization. By taking advantage of an intramolecular Diels–Alder reaction, we have developed a prodrug strategy for preparations of organic CO prodrugs that are stable during synthesis and storage, and yet readily release CO with tunable release rates under near physiological conditions. The effectiveness of the CO prodrug system in delivering a sufficient quantity of CO for possible therapeutic applications has been studied using a cell culture anti‐inflammatory assay and a colitis animal model. These studies fully demonstrate the proof of concept, and lay a strong foundation for further medicinal chemistry work in developing organic CO prodrugs.