ABSTRACT
The development of a new methodology for visualizing and detecting gases is imperative for various applications. Here, we report a novel strategy in which gas molecules are detected by signals from a reporter guest that can read out a host structural transformation. A composite between a flexible porous coordination polymer and fluorescent reporter distyrylbenzene (DSB) selectively adsorbed CO2 over other atmospheric gases. This adsorption induced a host transformation, which was accompanied by conformational variations of the included DSB. This read-out process resulted in a critical change in DSB fluorescence at a specific threshold pressure. The composite shows different fluorescence responses to CO2 and acetylene, compounds that have similar physicochemical properties. Our system showed, for the first time, that fluorescent molecules can detect gases without any chemical interaction or energy transfer. The host-guest coupled transformations play a pivotal role in converting the gas adsorption events into detectable output signals.
ABSTRACT
This study was performed to investigate the risk of cardiac events by eccentric or continuous dosing of nitrates in patients with healed myocardial infarction. A total of 573 patients with healed myocardial infarction were assigned to one of two groups: a nitrate-treatment (n =239) and a nontreatment (n =334) group. The nitrate-treatment group was further subdivided into a group receiving eccentric dosing of nitrates (n =153) and a group receiving continuous dosing of nitrates (n =86). The mean observation period was 11.2+/-8.2 months. The cardiac events investigated were nonfatal and fatal recurrent myocardial infarction, death from congestive heart failure, sudden death, worsening angina and rebound angina. Baseline characteristics were also compared among the three groups to determine any effects on outcome. Among the patients receiving eccentric or continuous dosing of nitrates, the rates of cardiac events were 12.7/1,000 person.year and 67.4/1,000 person.year, respectively, whereas the rate was 19.7/1,000 person.year in the nontreated patients. The incidence of cardiac events was significantly greater in patients receiving continuous dosing of nitrates than in the nontreated patients (p <0.05). Continuous dosing of nitrates thus increases cardiac events, and while eccentric dosing of nitrates does not increase them, it is also not effective at preventing them in patients with healed myocardial infarction.
