Laser performance of perylenebis (dicarboximide) dyes with long secondary alkyl chains

The laser performance and related photophysical properties of two very soluble perylene dyes with long chain secondary alkyl groups were investigated in cyclohexane solution. With a dye laser as pump source a tuning range of 555–580 nm was obtained at an optimum concentration of 3×10–4 M. The quantum efficiencies (=0.29 and 0.21) were better than 1/2 that of rhodamine 6G. No photodegradation was observed over an excitation period of several hours

Fluorescence and laser activity of some pyrazinyl Schiff-base derivatives

The emission and excitation spectra of a series of Schiff-base derivatives from 2-aminopyrazines and substituted benzaldehydes (I a-h) have been studied together with their fluorescence quantum yields (ϕf). Laser emission of three members of this series having high ϕf values, was observed in the violet spectral region upon pumping with a nitrogen laser (peak power 100 kW). Bathochromicafly shifted emission has also been observed in concentrated solutions (ca. 10-2 mol dm-3) at ca. 500 nm(λex = 337 nm). The enthalpy of association (AHa) of some derivatives has been evaluated and correlated to the nature of substituent. The association ability is higher in case of electron withdrawing groups compared with electron donating groups indicating that association occurs as a result of interaction between the electron-rich pyrazinyl moiety and the relatively electron deficient substituted phenyl rings.Molecular association between the p-methoxy derivative and 1,4-bis (β-pyridyl-2-vinyl) benzene (P2VB) laser dye has also been studied using fluorescence quenching and some relevant spectroscopic techniques

Fluorescence quenching of meso-substituted anthracenes by electron acceptors

The fluorescence quenching of some meso-susbstituted anthracenes was studied using organic acceptors as quenchers. The quenching process does not obey the Stern-Volmer relation and both medium viscosity and temperature effects indicate that static-quenching is the underlying mechanism with ground-state charge-transfer (CT) complex formation. The existence of the anticipated CT complexes has been verified by visible spectroscopy and thermal analysis

Correction to: Potentially modifiable factors contributing to outcome from acute respiratory distress syndrome: the LUNG SAFE study

Correction to: Intensive Care Med (2016) 42:1865\u20131876 DOI 10.1007/s00134-016-4571-

Resolved versus confirmed ARDS after 24 h: insights from the LUNG SAFE study

Purpose: To evaluate patients with resolved versus confirmed ARDS, identify subgroups with substantial mortality risk, and to determine the utility of day 2 ARDS reclassification. Methods: Our primary objective, in this secondary LUNG SAFE analysis, was to compare outcome in patients with resolved versus confirmed ARDS after 24\ua0h. Secondary objectives included identifying factors associated with ARDS persistence and mortality, and the utility of day 2 ARDS reclassification. Results: Of 2377 patients fulfilling the ARDS definition on the first day of ARDS (day 1) and receiving invasive mechanical ventilation, 503 (24%) no longer fulfilled the ARDS definition the next day, 52% of whom initially had moderate or severe ARDS. Higher tidal volume on day 1 of ARDS was associated with confirmed ARDS [OR 1.07 (CI 1.01\u20131.13), P = 0.035]. Hospital mortality was 38% overall, ranging from 31% in resolved ARDS to 41% in confirmed ARDS, and 57% in confirmed severe ARDS at day 2. In both\ua0resolved and confirmed\ua0ARDS, age, non-respiratory SOFA score, lower PEEP and P/F ratio, higher peak pressure and respiratory rate were each\ua0associated with mortality. In confirmed ARDS, pH and the presence of immunosuppression or neoplasm were also associated\ua0with mortality. The increase in area under the receiver operating curve for ARDS reclassification on day 2 was marginal. Conclusions: ARDS, whether resolved or confirmed at day 2, has a high mortality rate. ARDS reclassification at day 2 has limited predictive value for mortality. The substantial mortality risk in severe confirmed ARDS suggests that complex interventions might best be tested in this population. Trial Registration: ClinicalTrials.gov NCT02010073. \ua9 2018, Springer-Verlag GmbH Germany, part of Springer Nature and ESICM