Transforming waste into value: pomelo-peel-based nitrogen-doped carbon dots for the highly selective detection of tetracycline.

Tetracycline (TC) is widely used as a veterinary drug, and its residue in livestock products could enter the human body and cause damage. In this study, we developed an eco-friendly approach that utilized pomelo peel as a carbon source to synthesize new water-soluble N-doped carbon dots (P-NCDs) with blue fluorescence, obtaining a high quantum yield of up to 76.47% and achieving the goal of turning waste into value. Our prepared P-NCDs can selectively recognized TC, and their fluorescence was quenched based on the IFE. P-NCDs could measure the TC concentration in the linear range of 0-100 µmol L-1 with a detection limit (LOD, S/N = 3) as low as 0.045 µmol L-1. Furthermore, we have successfully applied our P-NCDs to the detection of TC in milk samples with convincing results within 90 s. Overall, our newly synthesized fluorescent sensor, P-NCDs, demonstrated huge potential to become an alternative way to detect TC in a simple, efficient, sensitive way without using any special instruments.

A Continuously Tunable Full-Color Emission Nitrogen-Doped Carbon Dots and for Ultrasensitive and Highly Selective Detection of Ascorbic Acid.

Nitrogen-doped carbon dots exhibiting excitation-dependent full-color emissions (F-NCDs) were prepared via the one-step hydrothermal method with citric acid and phenylenediamine. Specifically, the emission wavelength of the F-NCDs tuned from 452 nm to 602 nm due to the introduction of new energy levels by C=O and C=N functional groups. We exploited its stability in illumination, ionic strength, and pH, as well as its specificity, sensitivity, especially in ascorbic acid (AA) detection. F-NCDs could measure the AA concentration in the linear ranges of 0~0.1 and 0.1~1 mmol/L with the detection limit (LOD, S/N = 3) as low as 2.6 nmol/L. Additionally, we successfully detected AA in bovine serum with our F-NCDs and obtained the result within 1 min. Because of full-color emission features, we believe our F-NCDs have a great potential in fluorescent sensor detection.

Hepatoprotective effects and structure-activity relationship of five flavonoids against lipopolysaccharide/d-galactosamine induced acute liver failure in mice.

Acute liver failure (ALF) is a distinct clinical syndrome with high mortality and characterized by metabolic derangements, neurological complication, and multiple failures. Flavonoids exert great biological properties on anti-oxidation, anti-inflammation, and anti-apoptosis. After lipopolysaccharide (LPS)/d-galactosamine (d-GalN) administration, five flavonoids inhibited oxidative activities with reducing nitric oxide synthase (iNOS), malondialdehyde (MDA), and improving catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). They reduced the serum levels of alanine and aspartate aminotransferase (ALT, AST) and pro-inflammatory cytokines, prevented the phosphorylation of IKK, IκBα, and NF-κB/p65 in the NF-κB signaling pathway. Additionally five flavonoids inhibited hepatocyte apoptosis through increasing Bcl-2/Bax ratio and suppressing the Caspase family proteins. Chrysin, luteolin, apigenin, hesperetin and 3', 4'-dimethoxy hesperetin have apparently hepato-protective effects against ALF induced by LPS/d-GalN. The study found, the C2C3 double bond at A ring, and the hydroxyl group of C3' or C4' at B ring increased the protective activities, however, the effect of hydroxymethylation at C3' and C4' was reversed. In addition, apigenin has good hepatoprotective effects and potential as a promising therapeutic agent for ALF in clinical application.

[Effects of recombinant human erythropoietin on the immune function of premature rats].

OBJECTIVE: To observe the effect of recombinant human erythropoietin (rHuEPO) on immune function of premature rats. METHODS: RHuEPO of 250 IU/(kg.t) or 500 IU/(kg.t) was administered to premature rats every other day for nineteen days. The control premature rats were received normal saline. The changes of hemoglobin (Hb), serum erythropoietin (EPO), red blood cell (RBC) immune function, T lymphocyte proliferative responsiveness, and production of tumor necrosis factor alpha (TNF-alpha) were observed. RESULTS: Premature rats showed lower levels on Hb, RBC immune function, T cell responsiveness and production of TNF-alpha compared with mature rats at birth. The postnatal declines of Hb and RBC immune function were lessened in the treated groups of premature rats, the higher dosage group of 500 IU/(kg.t) was more significant than the lower dosage group of 250 IU/(kg.t). When experiments were over, Hb of control premature rats was (7.72 +/- 0.89) g/dl, Hb of premature rats received 500 IU/(kg.t) was (10.08 +/- 0.90) g/dl (P < 0.01). C3b-R% of control premature rats was (11.00 +/- 0.95)%, C3b-R% of premature rats received 500 IU/(kg.t) was (17.75 +/- 1.04)% (P < 0.01). IC-R% in control premature rats was (12.83 +/- 1.33)%, IC-R% of premature rats received 500 IU/(kg.t) was (10.50 +/- 1.67)% (P < 0.01). The postnatal rise of T cell responsiveness and the production of TNF-alpha in premature rats increased in the treated groups, which was more significant in the higher dosage group of 500 IU/(kg.t) than in the lower dosage group of 250 IU/(kg.t). The OD index of control premature rats was 0.159 +/- 0.014, the OD index of premature rats received 500 IU/(kg.t) was 0.354 +/- 0.050 (P < 0.01). TNF-alpha in control premature rats was (0.270 +/- 0.014) ng/ml, TNF-alpha of premature rats received 500 IU/(kg.t) was (0.415 +/- 0.010) ng/ml (P < 0.01). CONCLUSIONS: (1) Premature rats had lower RBC immune function and T cell responsiveness and underproduction of TNF-alpha at birth. (2) Premature rats had an improvement with the RBC immune function after rHuEPO administration. (3) Premature rats had improvements with T cell responsiveness and TNF-alpha after rHuEPO administration, and there was a positive correction between the RBC immune function and T cell responsiveness with the production of TNF-alpha.