RESUMEN
Transparent and flexible surface-enhanced Raman scattering (SERS) substrates have attracted much interest for the detection of probe molecules on the curved surfaces of real samples, but a facile route to fabricate such substrates is still lacking. Herein, we present a rationally designed, high-performance flexible SERS substrate fabricated using a simple drop and peel-off technique for the ultrasensitive detection of pesticides. The proposed SERS substrate consists of a polymethyl methacrylate (PMMA) film anchored with plasmonic silver nanoparticles (Ag NPs), which are photoreduced using chemically patterned ferroelectric templates. The photoreduced Ag NPs extracted onto the PMMA film offer strong electromagnetic enhancement and produce intensive hotspots for the effective enhancement of the Raman signal. They provide superior SERS performance for the detection of parathion (PT) and fenitrothion (FNT) at trace-level concentrations of 10-9 M and 10-10 M with excellent enhancement factors in the order of 108 and 109, respectively. Moreover, the Ag NP/PMMA SERS substrate has good spot-to-spot uniformity and batch-to-batch reproducibility with the reservation of high detection sensitivity even after the mechanical deformation of bending and torsion up to 50 cycles. The multiplex detection ability is also investigated for the simultaneous detection of PT and FNT. To ensure the practical feasibility, the in-situ, real-time detection of PT and FNT on the curved surfaces of tomato and lemon using a fiber-coupled Raman probe is performed with limits of detection of 4.24 × 10-8 M and 2.74 × 10-9 M. The proposed Ag NP/PMMA flexible SERS substrate possesses unique features, such as easy fabrication through a simple, economical, rapid process, and facilitates straightforward implementation of in-situ SERS detection on curved fruit/vegetable surfaces.
RESUMEN
The construction of novel electrocatalysts for efficient and economic electrochemical sensors is continuously a significant conceptual barrier for the point-of-care technology. Binary metal oxides with heterostructures have gained plenty of attention due to their promising physicochemical properties. Herein, we develop a rapid and sensitive electrochemical probe for the detection of flufenamic acid (FFA) by using a zinc manganate (ZnMnO)-modified electrode. The formation of ZnMnO was confirmed by various analytical techniques, such as X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and field-emission scanning electron microscopy with energy dispersive X-ray spectroscopy and elemental mapping. The ZnMnO-based electrocatalyst, which was used for the electrochemical detection of FFA, shows better performance than the previously reported electrode materials. The ZnMnO assay shows a linear quantitative range from 0.05 to 116 µM with a limit of detection of 0.003 µM and sensitivity of 0.385 µA µM-1 cm-2. Its good electrochemical performance can be ascribed to the large surface area, rapid charge mass transfer, copious active sites, and high carrier mobility. The electrochemical study displays that the fabricated ZnMnO-based sensor has the potential to be applied in the clinical analysis. This work constructs an advanced functional electrode material with a microscale architecture for the point-of-care technology.
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A general and practical cross-dehydrogenative coupling protocol between readily available trisubstituted α,ß-dehydro α-amino carboxylic esters and H-phosphites is described. This C(sp2)-H phosphorylation reaction proceeds with absolute Z-selectivity promoted by silver salt in a radical relay manner. The bulky tetrasubstituted ß-phosphonodehydroamino acids were obtained in grams and added new modules to the toolkit for peptide modifications.
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Herein we report a novel and straightforward protocol for the construction of valuable gem-BPs by means of proton-coupled electron-transfer (PCET)-triggered enamido C(sp2 )-H diphosphorylation. This reaction represents a rare example of realizing the challenging double C-P bond formation at a single carbon atom, thus providing facile access to a broad variety of structurally diverse bisphosphonates from simple enamides under silver-mediated conditions. Initial mechanistic studies demonstrated that the diphosphorylation involves two rounds of PCET-initiated radical relay process.
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BACKGROUND: Invasive fungal infections such as candidiasis and mold infections cause significant morbidity and mortality in seriously ill patients. Micafungin is an echinocandin antifungal agent with potent activity against most species of Candida and Aspergillus. We did this meta-analysis to clarify whether micafungin offers superior efficacy and safety compared with other antifungal agent for treating infections associated with invasive candidiasis. METHODS: We did a meta-analysis of randomized controlled trials to examine whether micafungin has superior efficacy and safety compared with other antifungal agents recommended by the treatment guidelines for fungal infection. Seven trials involving 2913 patients were included in this analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated. RESULTS: Micafungin was associated with significantly better treatment success compared with the comparator antifungal agents (modified intention to treat, 2851 patients; random-effects model, OR 1.20, 95%CI 1.00 - 1.45, P = 0.0487). In addition, micafungin was more effective than the comparators for antifungal prophylaxis of neutropenic patients undergoing hematopoietic stem cell transplantation (OR 1.47, 95%CI 1.08 - 2.00, P = 0.01). Although there was no significant difference between the compared regimens in terms of the incidence of adverse drug effects (OR 0.94, 95%CI 0.77 - 1.11), fewer patients treated with micafungin withdrew from the studies because of adverse events (OR 0.64, 95%CI 0.44 - 0.94). CONCLUSIONS: Micafungin has a good safety and tolerability profile, with an efficacy at least comparable to the other antifungal agents. Micafungin offers advantages over other agents for antifungal prophylaxis. Micafungin offers an appropriate alternative for antifungal prophylaxis rather than the treatment of invasive candida infections.
Asunto(s)
Antifúngicos/efectos adversos , Antifúngicos/uso terapéutico , Candidiasis Invasiva/tratamiento farmacológico , Equinocandinas/efectos adversos , Equinocandinas/uso terapéutico , Lipopéptidos/efectos adversos , Lipopéptidos/uso terapéutico , Humanos , Micafungina , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del TratamientoRESUMEN
OBJECTIVE: To observe the therapeutic effect of acupuncture treatment on stroke according to the acupoint selection of "Najia method of Ziwua Liuzhu" and to investigate the mechanism. METHODS: One hundred and ninety cases were randomly divided into a Ziwu Liuzhu group (n=95) and a routine acupuncture group (n=95). Five shu points on different meridians were selected according to the Tiangan (Heavenly Stems)-tables of "Najia method of Ziwu Liuzhu" in the Ziwu Liuzhu group, and the treatment was carried out within the period from Chen (7:00-9:00 AM) to Si (9:00-11:00 AM). In the routine acupuncture group, Fengchi (GB 20), Shuigou (GV 26), Waiguan (TE 5), etc. were selected to treat the patients immediately on first visit. The therapeutic effects of two groups were assessed by the scores of neural functial cinl deficiency, status of total living ability, blood rheological indexes and clinical comprehensive effectiveness. RESULTS: The total effective rate of 95.8% in the Ziwu Liuzhu group was significantly better than 80.0% in the routine acupuncture group. The scores of neural functional deficiency, main items of blood rheology and total living ability in the Ziwu Liuzhu group were significantly lower than those in the routine acupuncture group (all P < 0.05). CONCLUSION: Acupuncture treatment in the period from Chen to Si according to the acupoint selection of "Najia method of Ziwu Liuzhu" has a significant clinical effectiveness which is related with improvement of the indexes of blood rheology.