RESUMEN
Metal nanoclusters (MNCs) represent a promising class of materials for catalytic carbon dioxide and proton reduction as well as dihydrogen oxidation. In such reactions, multiple proton-coupled electron transfer (PCET) processes are typically involved, and the current understanding of PCET mechanisms in MNCs has primarily focused on the sequential transfer mode. However, a concerted transfer pathway, i.e., concerted electron-proton transfer (CEPT), despite its potential for a higher catalytic rate and lower reaction barrier, still lacks comprehensive elucidation. Herein, we introduce an experimental paradigm to test the feasibility of the CEPT process in MNCs, by employing Au18(SR)14 (SR denotes thiolate ligand), Au22(SR)18, and Au25(SR)18- as model clusters. Detailed investigations indicate that the photoinduced PCET reactions in the designed system proceed via an CEPT pathway. Furthermore, the rate constants of gold nanoclusters (AuNCs) have been found to be correlated with both the size of the cluster and the flexibility of the Au-S framework. This newly identified PCET behavior in AuNCs is prominently different from that observed in semiconductor quantum dots and plasmonic metal nanoparticles. Our findings are of crucial importance for unveiling the catalytic mechanisms of quantum-confined metal nanomaterials and for the future rational design of more efficient catalysts.
RESUMEN
α-Glucosidase (α-Glu) is implicated in the progression and pathogenesis of type II diabetes (T2D). In this study, we developed a rapid colorimetric technique using platinum nanoparticles stabilized by chitosan (Ch-PtNPs) to detect α-Glu activity and its inhibitor. The Ch-PtNPs facilitate the conversion of 3,3',5,5'-tetramethylbenzidine (TMB) into oxidized TMB (oxTMB) in the presence of dissolved O2. The catalytic hydrolysis of 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) by α-Glu produces ascorbic acid (AA), which reduces oxTMB to TMB, leading to the fading of the blue color. However, the presence of α-Glu inhibitors (AGIs) hinders the generation of AA, allowing Ch-PtNPs to re-oxidize colorless TMB back to blue oxTMB. This unique phenomenon enables the colorimetric detection of α-Glu activity and AGIs. The linear range for α-Glu was found to be 0.1-1.0 U mL-1 and the detection limit was 0.026 U mL-1. Additionally, the half-maximal inhibition value (IC50) for acarbose, an α-Glu inhibitor, was calculated to be 0.4769 mM. Excitingly, this sensing platform successfully detected α-Glu activity in human serum samples and effectively screened AGIs. These promising findings highlight the potential application of the proposed strategy in clinical diabetes diagnosis and drug discovery.
RESUMEN
Background: Homeostasis of thyroid hormones has significant effects on the cardiovascular system. The aim of this study was to investigate the association between free triiodothyronine (FT3) and adverse cardiovascular events in patients with acute coronary syndrome (ACS) who were undergoing percutaneous coronary intervention (PCI). Methods: A total of 1701 patients with ACS undergoing PCI were included in this study. All patients were divided into three groups according to the tertiles of FT3 level: the lowest tertile (FT3 < 4.51 pmol/L), the middle tertile (4.51 pmol/L ≤ FT3 < 4.89 pmol/L) and the highest tertile group (FT3 ≥ 4.89 pmol/L). The primary study endpoint was a composite of major adverse cardiovascular events (MACE), which included all-cause death, ischemic stroke, myocardial infarction, or unplanned repeat revascularization. Results: During a median follow-up period of 927 days, 349 patients had at least one event. Compared with patients with the highest tertile, those with the lowest tertile had a significantly higher incidence of MACE, all-cause death, MI, ischemic stroke and repeat revascularization (all p values < 0.05). In the multivariate Cox regression analysis, the middle tertile had similar risk of MACE (HR = 0.986, 95% CI 0.728-1.336, p = 0.929) as the highest tertile, but the patients with the lowest tertile had a 92.9% higher risk of MACE (HR = 1.929, 95% CI 1.467-2.535, p < 0.001). There was a non-linear relationship between FT3 and MACE and unplanned repeat revascularization (all p values for non-linear association < 0.001). Adding the tertiles of FT3 level into the baseline model yielded a significant improvement in discrimination for predicting MACE ( Δ AUC = 0.013, p = 0.025). Conclusions: A significantly reduced FT3 level was independently associated with a worse prognosis in patients with ACS undergoing PCI.
RESUMEN
A new series of complex anion ionic liquids (ILs) [Emim][BF3X] (X = CH3SO3, EtSO4, HSO4, Tosylate) were synthesized and characterized by nuclear magnetic resonance, elemental analysis, differential scanning calorimetry analysis, and thermogravimetry. The physicochemical properties of these ILs, such as density, viscosity, conductivity, and surface tension, were measured and correlated with thermodynamic and empirical equations in the temperature range of 293.15-358.15 K under ambient conditions, and the thermal expansion coefficient, standard molar entropy, lattice potential energy, viscosity activation energy, surface enthalpy, and surface entropy were further calculated from experimental values. According to the temperature-dependent viscosity and conductivity, [Emim][BF3X] ILs follow the Walden rule, and they are classified as "good (or super) ionic liquids".
RESUMEN
ABSTRACT Sarcopenia, a concept reflecting the loss of skeletal muscle mass, was reported to be associated with the prognosis of several tumors. However, the prognostic value of sarcopenia in patients with renal cancer remains unclear. We carried out this metaanalysis and systematic review to evaluate the prognostic value of sarcopenia in patients with renal cell carcinomas. We comprehensively searched PubMed, Embase, and Cochrane Library from inception to December 2018. Hazard ratio (HR) and 95% confidence interval (CI) were pooled together. A total of 5 studies consisting of 771 patients were enrolled in this quantitative analysis, 347 (45.0%) of which had sarcopenia. Patients with sarcopenia had a worse OS compared with those without sarcopenia (HR=1.76; 95%CI, 1.35-2.31; P <0.001). In the subgroup of patients with localized and advanced/metastatic diseases, sarcopenia was also associated with poor OS (HR=1.48, P=0.039; HR=2.14, P <0.001; respectively). With a limited sample size, we did not observe difference of PFS between two groups (HR=1.56, 95% CI, 0.69-3.50, P=0.282). In the present meta-analysis, we observed that patients with sarcopenia had a worse OS compared with those without sarcopenia in RCC. Larger, preferably prospective studies, are needed to confirm and update our findings.