a topoframe, denoted by $l_{ tau}$,  is a pair $(l, tau)$ consisting of a frame $l$ and a subframe $ tau $ all of whose elements are complementary elements in$l$. in this paper, we define and study the notions of a$tau $-real-continuous function on a frame $l$ and the set of realcontinuous functions $mathcal{r}l_tau $ as an $f$-ring.we show that $mathcal{r}l_{ tau}$is actually a generalization ...

Polyols and sulfate esters have recently been identified in the secondary organic aerosol (SOA) formed in the photooxidation of biogenic hydrocarbons both in the laboratory and under ambient atmospheric conditions. In the present study, the potential role of the reactions of epoxides in SOA to form diols and hydroxy sulfate esters is explored. Nuclear magnetic resonance methods were used to mon...

Aliphatic polyesters constitute an important class of polymers because of their biodegradability1,2 and biocompatability,2,3 which enable their use in drug delivery systems,2 artificial tissues,3 and commodity materials.4 Polyesters such as poly(butylene succinate) are commonly produced through condensation polymerization; however, this method is energy intensive, requiring high temperature and...

We have investigated the metabolism of chrysene (CHR) and 5-methychyrsene (5-MeCHR) by Shasta rainbow trout (Oncorhyncus mykiss) and Long Evans rat liver microsomes to assess the effect of a non-benzo ring methyl substituent on the reactions involved in the metabolism of polycyclic aromatic hydrocarbons (PAHs). Trout as well as rat liver microsomes metabolized both CHR and 5-MeCHR at essentiall...

Fluorescent polyesters have been prepared using ring-opening copolymerization by adding a fluorescent monomer to the reaction. The coloured polymers depolymerized and white polymer resynthesized from recovered monomers.

The mutagenic activities of benz(a)acridine, benz(c)acridine, and a number of their derivatives, including 12 epoxides and diol-epoxides, were examined in bacterial and mammalian cells to determine the importance of bay-region activation of azapolycyclic aromatic hydrocarbons. In Salmonella typhimurium strain TA98, the diastereomeric bay-region 3,4-diol-1,2-epoxides of benz(c)acridine, in which...

Several triterpenic derivatives, with the A-ring functionalized, were semisynthesized from oleanolic and maslinic acids. The reactivities of sulfites, sulfate, and epoxides in these triterpene compounds were investigated under different reaction conditions. Moreover, contracted A-ring triterpenes (five-membered rings) were obtained, by different treatments of the sulfate 7. From the epoxide 8, ...