Carbon dots as multifunctional fluorescent probe for Fe3+ sensing in ubiquitous water environments and living cells as well as lysine detection via "on-off-on" mechanism.

Iron and amino acids are essential nutrients for living organisms, and their deficiency or excess can cause a range of diseases. Therefore, there is considerable interest in developing sensing assays capable of detecting these nutrients with sensitivity, selectivity, and multifunctionality even in complex environments. In this report, hydrothermally synthesized blue fluorescent carbon dots (C-dots) from zinc gluconate were utilized for the detection of Fe3+ and lysine via "on-off" and "on-off-on" mechanisms, respectively. Specifically, the Fe3+ sensing assay achieved a broad linear range of 0-200 µM and a low limit of detection (LOD) of 1.9 µM. It is worth mentioning that the assay was also well adapted to natural aqueous environments (e.g., lake water), and its linear detection range could be extended to 0-1000 µM with a LOD of 3.3 µM. Furthermore, the assay was also effective for intracellular Fe3+ tracking. Most importantly, the assay could also be applied for the quantitative detection of lysine with a linear range of 0-1200 µM and LOD of 8.6 µM. Systematic mechanistic studies revealed that Fe3+ sensing was based on a static quenching process between C-dots and Fe3+, whereas a stronger complexation might have formed between Fe3+ and Lys, leading to the release of C-dots and thus the recovery of fluorescence.

Carbon Dots-Based Fluorescence Assay for the Facile and Reliable Detection of Ag+ in Natural Water and Serum Samples.

In this report, red-emissive carbon dots (C-dots) were facilely prepared from o-phenylenediamine via microwave-assisted hydrothermal treatment. The C-dots demonstrated excitation wavelength-independent emission with maximums at 621 nm that could be effectively quenched by Ag+ via static quenching. This phenomenon was exploited to establish a sensitive fluorescence assay with a low detection limit (0.37 µM) and wide linear range (0-50 µM). In addition, this assay demonstrated excellent selectivity toward Ag+, free from the interference of 16 commonly seen metal ions. Most importantly, the assay demonstrated high reliability toward samples in deionized water, mineral water, lake water, and serum, which could indicate potential applications for Ag+ monitoring in complicated natural and biological environments.

Sensitive, Selective and Reliable Detection of Fe3+ in Lake Water via Carbon Dots-Based Fluorescence Assay.

In this study, C-dots were facilely synthesized via microwave irradiation using citric acid and ethylenediamine as carbon precursors. The fluorescence emissions of the C-dots could be selectively quenched by Fe3+, and the degree of quenching was linearly related to the concentrations of Fe3+ presented. This phenomenon was utilized to develop a sensitive fluorescence assay for Fe3+ detection with broad linear range (0-250, 250-1200 µmol/L) and low detection limit (1.68 µmol/L). Most importantly, the assay demonstrated high reliability towards samples in deionized water, tap water and lake water, which should find potential applications for Fe3+ monitoring in complicated environments.

Usefulness of a Nurse-Led Program of Care for Management of Patients with Chronic Heart Failure.

BACKGROUND The aims of the present study were to determine whether a nurse-led program of care can improve medication adherence, quality of life (QoL), rates of rehospitalization, and all-cause mortality for chronic heart failure (CHF) patients. MATERIAL AND METHODS CHF patients were randomly assigned into either a control group or an intervention group. At 12 weeks, patients were followed up to evaluate the rate of medication adherence, QoL (as assessed by SF-12 physical and mental component score [PCS and MCS]), rehospitalization, and all-cause mortality. RESULTS We recruited 152 patients. No significant differences in demographics, comorbidities, CHF severity, or etiology at baseline were observed. At discharge, no significant differences in medications prescription, PCS (46 vs. 45), or MCS (55 vs. 56) were observed. However, at 12-week follow-up, compared to the control group, patients in the intervention group were more likely to keep on medications therapy, with a significantly higher use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker [73.8% vs. 59.7%], beta-blocker (62.5% vs. 51.4%), and aldosterone receptor antagonist (60% vs. 54.2%). Both PCS (35 vs. 40) and MCS (42 vs. 49) were also significantly lower in the control group versus the intervention groups (P<0.05). Patients in the control group had higher incident rate of rehospitalization (8.0% vs. 5.2% per person-week) than in the intervention group, with an incident rate ratio of 1.54 (95% confidence interval [CI]: 1.06-2.23). CONCLUSIONS A nurse-led discharge program of care can be a cost-effective and feasible approach for management of CHF patients in China.