Dicationic, zwitterionic and "conventional" yttrium compounds act as catalysts for the primary or secondary amine-initiated immortal ROP of rac-lactide; amine-terminated, highly heterotactic poly(rac-lactides) with narrow polydispersities and well-controlled molecular weights are prepared in this manner.

in this paper, the performance evaluation of a two-way hybrid photovoltaic/thermal (pv/t) solar collector was analytically and experimentally carried out. mathematical expressions for operating parameters in glass to glass and glass to tedlar pv/t solar collectors were developed and experimentally validated by a glass to tedlar pv/t solar collector system. also the influence of air flow rate on...

This paper deals with the performance of a heat pipe solar collector. The solar collector consisted of an interconnected heat pipe so as to reduce the production cost by using an interconnected heat pipe because all the heat pipes can be evacuated, sealed and tested at once. Performance of a prototype of the heat pipe solar collector was experimentally examined, and the results were compared wi...

Oxidation of the biologically important polyamines spermine and spermidine by plasma amine oxidase (PAO) was specified many years ago to occur at the terminal primary rather than internal secondary amine positions. However, the finding of sequential enzymatic conversion of spermine to spermidine and then to putrescine (1, 4-butanediamine) is superficially suggestive of metabolism at the seconda...

I AI3STI1ACT The mechanism of field enhnncctl secondary emission has been studied es-pcrimcntally in detail for KC1 low density transmission dynodes transferred in a dry nitrogen atmosphere. By means of a Kelvin probe located at the center of a collector, dynode surface potentials and their relationship with collector potential , secondary yield, primary energy and current density have been stu...

FeII- and α-ketoglutarate-dependent halogenases oxygenases can catalyze site-selective functionalization of C−H bonds via a variety C−X bond forming reactions, but achieving high chemoselectivity for using non-native functional groups remains rare. The current study shows that directed evolution be used to engineer variants the dioxygenase SadX address this challenge. Site-selective azidation s...

This experimental study is intended to explore the heat performance of a novel vacuum tube heat collector with thermal storage. In order to enhance the heat transfer performance, we add radial metal fins to the U-tube which is used as the heat transfer channel of water. Meanwhile, in order to increase the thermal capacity of the heat collector, the heat collector model is designed to be larger ...

The site of outflow resistance leading to elevated intraocular pressure in primary open-angle glaucoma is believed to be located in the region of Schlemm's canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Tradit...