RESUMEN
We determine the presence of four open-form configurational isomers for an unsubstituted metastable-state photoacid (mPAH) of the tricyanofuran (TCF) type in solution, at room temperature, via 2D NMR experiments. Electronic structure calculations are carried out to predict the relative stability of the isomers found experimentally and their isomerization barriers. According to the calculated rate constants for isomerization, the molecule can freely interconvert between the open-form isomers, thereby providing a thermal pathway between the isomers that might be better suited to access the cyclized closed-form configuration and those that are not. In establishing the open form isomeric makeup of the TCF mPAH under study, this work establishes the need to consider the four isomers in further studies on the thermal and excited-state isomerization processes and substituent effect thereon.
RESUMEN
Small changes in the pH gradient play a critical role in numerous biological and chemical pathways. Systems capable of monitoring and regulating these changes with high sensitivity and minimum photo-fatigue are in demand. Herein, we propose a visible light-triggered molecular system that allows for reversible regulation of acidity and fluorescence. This robust bi-functional system opens a new horizon towards novel studies that rely on small changes in acid-mediated controlled processes with high sensitivity. The two photosensitive compounds employed, a metastable-state photoacid (mPAH) and a boron-dipyrromethene (BODIPY) derivative, allow for consistent modulation of both fluorescence (based on the working principle of the inner filter effect) and pH (around a magnitude) over multiple cycles.
RESUMEN
OBJECTIVE: There are limited studies in Latin America regarding the chronic consequences of the Chikungunya virus (CHIK), such as post-CHIK chronic inflammatory rheumatism (pCHIK-CIR). We assessed the largest cohort so far of pCHIK-CIR in Latin America, at the municipality of La Virginia, Risaralda, a new endemic area of CHIK in Colombia. METHODS: We conducted a cohort retrospective study in Colombia of 283 patients diagnosed with CHIK that persisted with pCHIK-CIR after a minimum of 6 weeks and up to a maximum of 26.1 weeks. pCHIK cases were identified according to validated criteria via telephone. RESULTS: Of the total CHIK-infected subjects, 152 (53.7%) reported persistent rheumatological symptoms (pCHIK-CIR). All of these patients reported joint pains (chronic polyarthralgia, pCHIK-CPA), 49.5% morning stiffness, 40.6% joint edema, and 16.6% joint redness. Of all patients, 19.4% required and attended for care prior to the current study assessment (1.4% consulting rheumatologists). Significant differences in the frequency were observed according to age groups and gender. Patients aged >40 years old required more medical attention (39.5%) than those ≤40 years-old (12.1%) (RR=4.748, 95%CI 2.550-8.840). CONCLUSIONS: According to our results, at least half of the patients with CHIK developed chronic rheumatologic sequelae, and from those with pCHIK-CPA, nearly half presented clinical symptoms consistent with inflammatory forms of the disease. These results support previous estimates obtained from pooled data of studies in La Reunion (France) and India and are consistent with the results published previously from other Colombian cohorts in Venadillo (Tolima) and Since (Sucre).
