Biochemistry behind firmness retention of jujube fruit by combined treatment of acidic electrolyzed water and high-voltage electrostatic field.

Harvested jujube (Zizyphus jujuba Mill) is prone to softening due to active metabolism. This study investigated the effects of acidic electrolyzed water (AEW), high-voltage electrostatic field (HVEF) and their combination (AEW + HVEF) on softening and associated cell wall degrading enzymes (CWDEs), cell membrane integrity and antioxidant system of 'Huping' jujube during storage at 0 ± 1 °C. The results indicated that fruit subjected to AEW + HVEF, AEW or HVEF treatments maintained firmness 15.7%, 10.7%, and 5.3% higher than that of untreated control fruit at the end of 90 days cool storage. Fruit treated with AEW + HVEF could better maintain cell membrane integrity and exhibit lower activities of CWDEs and higher antioxidant capacity than that treated with either AEW or HVEF. Correlation analysis suggested that inhibition of softening was associated with reduction of CWDEs activities, and maintenance of membrane integrity and antioxidant system.

Combined Treatment of Acidic Electrolyzed Water and High-Voltage Electrostatic Field Improves the Storage Quality of Huping Jujube (Ziziphus jujuba Mill. cv. Huping).

Fresh jujube is prone to rapid deterioration after harvest due to its active metabolism and rich nutrients. This study aimed to investigate the effects of acidic electrolyzed water (AEW), a high-voltage electrostatic field (HVEF) and a combination of AEW and HVEF (AEW + HVEF) treatments on the storage quality of Huping jujube (Ziziphus jujuba Mill. cv. Huping) stored at 0 ± 1 °C for 90 days. The results showed that the fruits treated with AEW + HVEF exhibited better storage quality than those treated with either AEW or HVEF alone. Specifically, the fruits treated with AEW + HVEF maintained higher levels of nutrients and taste compounds, including total soluble solid (TSS), total soluble sugar, reducing sugar and titratable acidity (TA), as well as lower respiration rate, weight loss, decay index and TSS/TA ratio. Additionally, the AEW + HVEF treatment could delay the increase in reddening index, a* and color change (ΔE) values, and the decrease in L* and b* values, by retarding the degradation of chlorophyll and accumulation of carotenoids and flavonoids, thereby preserving the more desirable appearance color. Furthermore, the combined treatment could enhance the glutathione reductase (GR) activity and 2,2'-azino-bis-(3-ethylbenzothizoline)-6-sulfonic acid (ABTS) +-scavenging ability. Thus, the AEW + HVEF treatment is a potential method for Huping jujube preservation.

One-step microwave synthesis of red-emissive carbon dots for cell imaging in extreme acidity and light emitting diodes.

Red emissive carbon dots (R-CDs) have received great attention in biological fields due to their deep tissue penetrability, great bioimaging capability, low interference from auto-fluorescence, and potential for optoelectronic applications. Herein, excitation-independent, highly acid-sensitive R-CDs were successfully obtained via one-step microwave treatment of o-phenylenediamine (o-PD) and phosphoric acid and carefully purified by column chromatography. The relationship between the fluorescence emission and surface groups of the R-CDs was studied in detail using XPS, NMR, and fluorescence spectroscopy, and the different mechanisms of action of the R-CDs and acid in H2O and ethanol were determined. The excellent anti-interference ability and biocompatibility of the R-CDs were confirmed, and the probes were successfully used for imaging A549 and Escherichia coli (E. coli) cells in extreme acidity. Finally, based on their relatively high quantum yield and long wavelength emission, the application potential of the R-CDs in the fabrication of red light-emitting diodes (LEDs) was investigated.

The fabrication and the use of immobilized cells as test organisms in a ferricyanide-based toxicity biosensor.

Cell immobilization is an effective method to prolong the lifetime of a microorganism and has proven feasibility in some other biosensors. Thus, we studied the use of Escherichia coli immobilized by agar, gelatin, an agar/gelatin mixture, chitosan, and polyvinyl alcohol (PVA) to screen toxicity electrochemically. The E. coli immobilized by PVA gel showed the highest apparent bioactivity and the longest storage time in pH 7.0 phosphate-buffered saline solution. Furthermore, the E. coli immobilized by different gels was applied in the toxicity determination via a reported ferricyanide-mediated electrochemical method, where 3,5-dichlorophenol (DCP) was used as a model toxin. The E. coli immobilized by PVA showed the highest sensitivity to DCP, and the corresponding value of 50% inhibition concentration was 9.62 mg L-1 . Inhibition concentrations were in the range of 6.32 to 13.75% when the E. coli immobilized by PVA was challenged by wastewater, which were comparable with values obtained with the standard luminescent bacteria method (effective inhibition were in the range 7.96-25.42% for the same samples). Given the apparent bioactivity, storage ability, and sensitivity to toxin, PVA was the best polymer to confine cells among the polymers used in the present study. Environ Toxicol Chem 2018;37:329-335. © 2017 SETAC.

A rapid and sensitive colorimetric measurement of antibiotic efficacy against Escherichia coli in vitro.

A common dye of prussian blue (PB) as an indicator was used to develop a colorimetric method for detecting the efficacy of the antibiotics in vitro. Considering the electronic production capacity of microbial respiration, ferricyanide was employed in transferring electrons from target microorganism of Escherichia coli (E. coli) to produce ferrocyanide. Subsequently, ferrocyanide reacted with ferric ions to form PB. In view of relationship between the PB yield and the bacterial activity, the efficacy of the antibiotics on E. coli was directly detected at 700 nm of PB absorption. When the 5% activity of antibiotics on 20 isolates of E. coli was quantified as 5% efficacy, the applied concentrations of eight antibiotics, such as cefepime, ceftriaxone sodium, cefoperazone sodium, piperacillin sodium, amoxicillin, gentamicin, amikacin and levofloxacin were 2, 2, 4, 4, 10, 4, 8 and 8 µg mL⁻¹, respectively. To compare with minimum inhibitory concentration results obtained by Clinical and Laboratory Standards Institute broth macrodilution method, the results of PB methods showed good agreements except with gentamicin. Paired t-test result (P) also showed that difference between two methods was statistically significant (P = 0.006).

Changes in the radical scavenging activity of bacterial-type douchi, a traditional fermented soybean product, during the primary fermentation process.

We studied the effects of isoflavones and peptides on antioxidant activities of bacterial-type douchi during fermentation. Radical scavenging activities increased with increasing fermentation time. Isoflavone conversion was not obvious, while soy protein hydrolyzed dramatically during fermentation. These results suggest that soybean peptides rather than isoflavones result in variations in antioxidant activity in bacterial-type douchi.

Antithrombotic and fibrinolytic activities of methanolic extract of aged sorghum vinegar.

Antithrombotic activities, namely, in vitro platelet aggregation and in vivo pulmonary thrombosis, of the methanolic extract of aged vinegar were evaluated. The ability of the extract to inhibit platelet aggregation induced by adenosine diphosphate (ADP) and thrombin was concentration-dependent. IC(50) values for the inhibition of platelet aggregation induced by ADP and thrombin were 1.7 +/- 0.3 and 8.9 +/- 1.9 mg/mL, respectively. When administered orally at >100 mg/kg of body weight, the extract protected the rats against thrombotic death induced by collagen and epinephrine. Furthermore, the low molecular weight fraction of the extract showed strong fibrinolytic activity and altered coagulation parameters such as activated partial thromboplastin time (APTT), prothrombin time (PT), and throbin time (TT) in rat platelet. These results suggested that the antithrombotic ability of the vinegar extract corresponded to both antiplatelet and anticoagulation activities.

[Evaluation of direct digital radiography image quality in dentistry].

PURPOSE: To evaluate the quality of direct digital radiograph according to its application in dentistry. METHODS: 1195 patients with dental caries, periodontal diseases, periapical diseases, trauma of teeth or hypodontia were tested with Trophy elitys Radio Visio Graphy(RVG) and the quality of the tests was evaluated at four levels. RESULTS: It was convenient to operate RVG and easy to save the images, which reduced the amount of X-rays. 1587 pictures were taken, among which 92.3% was at level I, 6.3% was at level II,1.14% was at level III and level IV. CONCLUSIONS: The quality of the images at different positions is good, which can meet the requirement for clinical diagnosis. However, the radiography receptor should be improved for better images.