Pyridinium derivatives of histamine are potent activators of cytosolic carbonic anhydrase isoforms I, II and VII

A series of positively-charged derivatives has been prepared by reaction of histamine with substituted pyrylium salts. These pyridinium histamine derivatives were investigated as activators of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1) and more precisely the human isoforms hCA I, II and VII. Activities from the subnanomolar to the micromolar range were detected for these compounds as activators of the three isoforms, confirming the validity of current and previous designs. The substitution pattern at the pyridinium ring was the main factor influencing activity, the three isoforms showing different structural requirements for good activity, related with the number of pyridinium substituting groups and their nature, among various alkyl, phenyl and para-substituted styryl moieties. We were successful in identifying nanomolar potent and selective activators for each isozyme and also activators with a relatively good activity against all isozymes tested--valuable lead compounds for physiology and pathology studies involving these isozymes.     

A Stark future for quantum control

We present an overview of developments using the nonresonant dynamic Stark effect within the fields of time-resolved molecular dynamics and quantum control, drawing on examples from our own recent work. Particular emphasis is placed on the notion that "dynamics" and "control" are not distinct disciplines and that a clear synergy exits between these areas which has, up to now, been somewhat underexploited. The dynamic Stark effect is a universal interaction which we expect to have broad applicability.     

Investigation of ion-electrode interactions of linear polyimides and alkali metal ions for next generation alternative-ion batteries

Organic electrode materials offer unique opportunities to utilize ion-electrode interactions to develop diverse, versatile, and high-performing secondary batteries, particularly for applications requiring high power densities. However, a lack of well-defined structure–property relationships for redox-active organic materials restricts the advancement of the field. Herein, we investigate a family of diimide-based polymer materials with several charge-compensating ions (Li⁺, Na⁺, K⁺) in order to systematically probe how redox-active moiety, ion, and polymer flexibility dictate their thermodynamic and kinetic properties. When favorable ion-electrode interactions are employed (e.g., soft K⁺ anions with soft perylenediimide dianions), the resulting batteries demonstrate increased working potentials and improved cycling stabilities. Further, for all polymers examined herein, we demonstrate that K⁺ accesses the highest percentage of redox-active groups due to its small solvation shell/energy. Through crown ether experiments, cyclic voltammetry, and activation energy measurements, we provide insights into the charge compensation mechanisms of three different polymer structures and rationalize these findings in terms of the differing degrees of improvements observed when cycling with K⁺. Critically, we find that the most flexible polymer enables access to the highest fraction of active sites due to the small activation energy barrier during charge/discharge. These results suggest that improved capacities may be accessible by employing more flexible structures. Overall, our in-depth structure–activity investigation demonstrates how variables such as polymer structure and cation can be used to optimize battery performance and enable the realization of novel battery chemistries.

Organic electrode materials offer unique opportunities to utilize ion-electrode interactions to develop diverse, versatile, and high-performing secondary batteries, particularly for applications requiring high power densities.     

利用便携式示波器轻松进行浮动测量

泰克TPS2000系列示波器采用隔离通道（IsolatedChannel^TM）技术，提供厂四条隔离通道、全功能、电池操作的示波器。该仪器提供厂高达200MHz的带宽和2GS／s的实时取样速率，一个隔离外部触发器和8小时连续电池操作能力，TPS2000系列示波器用途广泛。使得工程师和技术人员能够在实验室或现场迅速、精确、经济地进行浮动测量和差分测量。     

Synthesis of nanosized silver colloids by microwave dielectric heating

Silver nanosized crystallites have been synthesized in aqueous and polyols viz., ethylene glycol and glycerol, using a microwave technique. Dispersions of colloidal silver have been prepared by the reduction of silver nitrate both in the presence and absence of stabilizer poly(vinylpyrolidone) (PVP). It was observed that PVP is capable of complexing and stabilizing Ag nanoparticles formed through the reduction of Ag⁺ ions in water and ethylene glycol. In the case of ethylene glycol, it has been shown that the use of PVP leads to particles with a high degree of stability. The colloids are stable in glycerol for months even in the absence of stabilizer.     

基于PLD的通信产品中的宏功能

本文介绍了由ＡｌｔｅｒａＦＬＥＸ１０ＫＰＬＤ优化的几个功能模块的发展，讨论了用通信产品开发的宏功能特性。     

A probabilistic inventory model for deteriorating items with lead time equal to one scheduling period

A probabilistic inventory model for continuously deteriorating items is developed, in which the lead time is assumed to be of one scheduling period, shortages are not allowed, time is treated as discrete variable, and deterioration is assumed to be a constant fraction of the on hand inventory. The developed model is related to the EOQ model for deteriorating items. An example is given to illustrate the derived results.     

Quantum geometry from coordinate transformations relating quantum observers

The relativity principle that the law of propagation for light has the same form for all macroscopic observers is extended to include quantum observers; i.e., observers who may be large, but not infinitely large, by comparison with quantum mechanical systems. This leads to the extension of the covariance group from the diffeomorphisms to the conservation group (which is the largest group of coordinate transformations under which conservation laws are covariant statements) and, thus, to the quantum geometry and quantum unified field theory considered in a previous paper.