Intermediate aminophenol enables hectogram-scale synthesis of highly bright red carbon quantum dots under ambient conditions.

Carbon quantum dots (C-dots) have developed into potential nanomaterials for lighting, catalysis and bioimaging because of their excellent optical properties and good biocompatibility. However, it is still a challenge to produce efficient red emitting carbon quantum dots (R-C-dots) due to their obscure formation mechanism. This work offered a method to reveal the formation process from the precursor o-phenylenediamine (o-PDA) to R-C-dots. Different from traditional hydrothermal reactions, R-C-dots were synthesized at relatively low temperature and ambient pressure. The pre-oxidation intermediate aminophenol played an important role in the synthesis of R-C-dots, which further cross-linked and polymerized with o-PDA in an acid environment to form R-C-dots. The obtained R-C-dots had a photoluminescence quantum yield of up to 33.26% and excellent two-photon fluorescence properties. A white light-emitting diode (WLED) based on R-C-dots as the red phosphor exhibited standard white light CIE color coordinates of (0.33, 0.33) with a correlated color temperature of 5342 K and a high color rendering index (CRI) of 94.5. The obtained rendering index is the highest value among WLEDs with color coordinates of (0.33, 0.33) based on C-dots. This work provides a new perspective for the controllable large-scale synthesis of red C-dots.

Self-Precipitation of Highly Purified Red Emitting Carbon Dots as Red Phosphors.

Colloidal carbon dots (C-dots) have attracted a great deal of attention for their unique optical properties. However, it is still a challenge to obtain highly purified C-dots without using multiple-step purification or postsize selection. In this work, a self-precipitation hydrothermal reaction was used to synthesize red-emitting C-dots (R-C-dots) using o-phenylenediamine (o-PDA) as a precursor without using any catalyst. The R-C-dots are able to precipitate on the wall of the reactor, which enables us to obtain solid-state C-dots with high purity. The R-C-dots have a photoluminescence quantum yield (PLQY) of as high as 36.75%, which is among the highest PLQY values reported previously for R-C-dots without using catalysts. The transient PL and transient absorption spectra revealed that 5,14-dihydroquinoxalino[2,3-b]phenazine linked on the surface of the C-dots determined the red luminescence behavior. This work provides a new path for the controllable synthesis of high-purity R-C-dots, showing potential applications in optoelectronic devices.

Facile Fabrication of Anthocyanin-Nanocellulose Hydrogel Indicator Label for Intelligent Evaluation of Minced Pork Freshness.

In order to develop a reliable and rapid method for meat freshness detection, nanocellulose (TOCNF) prepared via the TEMPO (2,2,6,6-tetramethylpiperidine oxidation) oxidation method was used as raw material to prepare hydrogels using Zn2+ coordination and binding. Physicochemical properties such as water absorption and porosity were analyzed. It was further used to select suitable hydrogels for the preparation of indication labels after anthocyanin adsorption, and it was applied in the freshness detection of fresh minced pork. Five percent TOCNF (w/w) aqueous solution was homogenized by high shear for 4 min, and 20% (w/w) zinc chloride solution was added to it, so that the concentration of zinc ions could reach 0.25 mol/L. After standing for 24 h, the hydrogel was obtained with good water absorption and a porous three-dimensional network structure. The activation energies of volatile base nitrogen (TVBN) and anthocyanin indicating label color changes were 59.231 kJ/mol and 69.453 kJ/mol, respectively. The difference between the two is within 25 kJ/mol, so the prepared indicator label can accurately visualize the shelf life of fresh pork.

Reduction of oil uptake in vacuum fried Pleurotus eryngii chips via ultrasound assisted pretreatment.

The reduction of oil uptake in vacuum-fried Pleurotus eryngii chips by ultrasound assisted pretreatment was investigated regarding the pore structure changes. Pore structure of P. eryngii chips with four pretreatments, such as blanching, blanching + osmosis, blanching + ultrasound and blanching + ultrasound assisted osmosis was determined by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). In addition, the quality parameters of vacuum-fried P. eryngii chips such as hardness, rehydration ratio, reducing sugar, protein and oil content were also measured. The results showed that the oil absorption of vacuum fried P. eryngii chips was affected by the porous structure. The oil content of vacuum fried P. eryngii chips was significantly and positively correlated with the pores with diameters above 50, 5-50, and 0.5-5 µm in the samples both before and after vacuum frying, while negatively correlated with the pores with diameters below 0.5 µm. Ultrasound pretreatment changed the microporous structure of P. eryngii chips, effectively hindering the oil absorption of samples. In particular, ultrasound assisted osmosis pretreatment induced the formation of more micropores. It was concluded that blanching + ultrasound assisted osmosis pretreatment is a promising method to reduce oil absorption and improve the quality of vacuum fried foods.

Effect of nano-silica coating combined with pressurized Ar treatment on postharvest quality and reactive oxygen species metabolism in sweet cherry fruit.

The mechanisms of effect of nano-silica coating and pressurized Ar on regulating reactive oxygen species (ROS) generation and scavenging in the senescence of sweet cherries remains unclear. The amounts of reactive oxygen species, hydrogen peroxide, non-enzymatic antioxidants and antioxidases, and cell membrane lipid peroxidation in sweet cherries were determined. Nano-silica coating, pressurized Ar, and the combination of these two treatments, all significantly delayed senescence by suppressing decay rate, and maintained good sensory quality. In additional, all treatments inhibited the generation and accumulation of superoxide anion and hydrogen peroxide, and mitigated the lipid peroxidation of cell membranes of sweet cherries. The combination of these two treatments maintained higher contents of ascorbic acid and glutathione, and enhanced the activities of antioxidases in sweet cherries. It is suggested that nano-silica coating and pressure Ar mediated the ROS metabolism, which might have a role in retaining the quality sweet cherries during cold storage.

Antioxidant activities of chlorogenic acid derivatives with different acyl donor chain lengths and their stabilities during in vitro simulated gastrointestinal digestion.

In this study, chlorogenic acid (CA) was acylated with vinyl esters of different carbon chain lengths under the action of the lipase Lipozyme RM. Five CA derivatives (C2-CA, C4-CA, C6-CA, C8-CA, and C12-CA) with different lipophilicities were obtained, and their digestive stabilities and antioxidant activities were evaluated. The lipophilicities were positively correlated with the digestive stabilities of CA derivatives. The antioxidant activities of CA derivatives did not change with the reduction of phenolic hydroxyl groups, and their capacity to scavenge 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) were similar to those of CA. In cellular antioxidant activity (CAA) tests, it was found that the capacity of these derivates to cross cell membranes were enhanced upon enhancing lipophilicity, and their antioxidant activities were improved. C12-CA showed the best antioxidant activity with a median effective dose (EC50) of 9.40 µg/mL, which was significantly lower than that of CA (i.e., 29.08 µg/mL).

Solubility, structural properties, and immunomodulatory activities of rice dreg protein modified with sodium alginate under microwave heating.

This research aims to investigate the solubility, structural properties, and immunomodulatory of rice dreg protein (RDP) modified with sodium alginate. The modification was done by wet heating assisted with microwave treatment. The solubility, emulsifying properties at pH 2-12, amino acid composition, molecular weight distribution, circular dichroism (CD) spectroscopy, and FTIR spectra of modified RDP were analyzed and discussed. Results showed that Maillard reaction could significantly enhance the solubility and emulsifying capacity of RDP. Further, an animal model for cyclophosphamide-induced immunodeficiency was designed to evaluate the immunomodulatory effect of modified RDP. It is therefore suggested that modified RDP could improve the immunomodulatory effect of immunosuppressed mice, and the immunomodulation was concentration dependent, being generally enhanced by increased concentrations. This research revealed that glycosylation modification of RDP through Maillard reaction by wet heating assisted with microwave treatment may be successfully applied to improve the physicochemical properties and bioactive benefits of the final product.

Anticancer activity of a novel glycoprotein from Camellia oleifera Abel seeds against hepatic carcinoma in vitro and in vivo.

Glycoproteins are naturally occurring biological macromolecule that possess known pharmacological properties. This study investigated the anticancer potential of a new glycoprotein, COG2a with the weight-average molecular weight of 25.9 kDa, isolated from Camellia oleifera Abel seeds by multiple column chromatography and the mechanism of anticancer action. MTT assay showed that the maximum inhibition rate of COG2a on HepG2 cells was 92.1%. Electron microscopic and fluorescence microscopy observation indicated that the HepG2 cells treated with COG2a exhibited typical apoptotic morphological character. Flow cytometry manifested that COG2a induced the cell cycle arrest at the G2 phases and decreased in mitochondrial membrane potential on the HepG2 cells. Western blotting exhibited that COG2a increased the expressions of the pro-apoptotic protein caspase-3 and Bax and decreased the expression of the anti-apoptotic proteins Bcl-2. Additionally, COG2a exerted an obvious anticancer effect on tumor-bearing mice and the maximum tumor inhibition rate is 72.77%. It also can promote the mouse thymus and pancreas index, the number of T lymphocytes cell subset and interferon-gamma to increase. These results indicate that COG2a exhibits in vitro and in vivo anticancer activities that associate with its immunopotentiation properties and may serve as a potential anticancer agent.

Recent Developments in Film and Gas Research in Modified Atmosphere Packaging of Fresh Foods.

Due to the rise of consumer's awareness of fresh foods to health, in the past few years, the consumption of fresh and fresh-cut produces has increased sturdily. Modified atmosphere packaging (MAP) possesses a potential to become one of the most appropriate technologies for packaging fresh and fresh-cut produces. The MAP has advantages of extending the shelf-life, preserving or stabilizing the desired properties of fresh produces, and convenience in handing and distribution. The success of MAP-fresh foods depends on many factors including types of fresh foods, storage temperature and humidity, gas composition, and the characteristics of package materials. This paper reviews the recent developments highlighting the most critical factors of film and gas on the quality of MAP fresh foods. Although the innovations and development of food packaging technology will continue to promote the development of novel MAP, concentrated research and endeavors from scientists and engineers are still important to the development of MAP that focuses on consumers' requirements, enhancing product quality, environmental friendly design, and cost-effective application.

Extraction optimization of polysaccharides from Chinese rice wine from the Shaoxing region and evaluation of its immunity activities.

BACKGROUND: Chinese rice wine is well known for its unique flavor and high nutritional value. It is of interest to investigate the functional components of Chinese rice wine and their health benefits. RESULTS: Response surface design of three factors - pH, ethanol concentration and precipitation time - at three levels was utilized to optimize the extraction of Chinese rice wine polysaccharide (CRWP). The results indicated that the CRWP yield was 77.287% at the optimal levels for pH 8.4, ethanol concentration 88% and precipitation time 23 h. In addition, immune activity of CRWP was investigated by measuring body weight, spleen index and thymus index. Furthermore, immunity activity of CRWP was investigated by measuring lymphocyte proliferation, phagocytic index and phagocytic percentage of immunosuppressed mice. Compared with the control mice and model mice, it was found that CRWP has beneficial immune activities in vivo. CONCLUSION: These findings indicate that CRWP has immune activities in vivo by modulating the immune response, and implies full development and utilization of the nutritional value of Chinese rice wine. However, further work will be conducted in the future to elucidate the structure-bioactivity relationship for CRWP.

Extraction optimization and bioactivity of exopolysaccharides from Agaricus bisporus.

Response surface methodology was used to optimize the extraction parameters of EPS produced by Agaricus bisporus MJ-0811 in submerged culture. The optimal levels for ethanol concentration (85%, v/v), pH (8) and precipitation time (22 h) were determined, and EPS production was estimated at 2.71 g/L. The actual yield of EPS under these conditions was 2.69 g/L. In addition, the antioxidant activity of EPS was investigated by measuring its scavenging ability on superoxide radicals and hydroxyl radicals in vitro. Furthermore, the hypoglycemic activity of EPS was investigated by measuring its effects on body weights and blood glucose of diabetic mice. The study suggests that EPS has beneficial antioxidant activities (hydroxyl radical-scavenging activities, superoxide radical-scavenging activities) in vitro, anti-diabetic effect on alloxan induced diabetic mice. The EPS from A. bisporus may be a novel resource of natural antioxidants and anti-diabetic agents for use in the functional food or medicine.

[Protein-protein interaction network of receptor activator of nuclear factor-kappaB ligand and macrophage colony-stimulating factor induced differentiation of osteoclasts].

OBJECTIVE: To systemically investigate receptor activator of nuclear factor-kappaB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) induced differentiation of osteoclasts. METHODS: Mouse protein-protein interaction(PPI) database NIA and published microarray dataset GES16749 were used to construct and analyze PPI network of RANKL and M-CSF induced mouse monocyte RAW264.7. RESULTS: In the PPI network, transforming growth factor beta receptor 1 (TGFBR1), Rous sarcoma oncogene (SRC), myelocytomatosis oncogene(MYC) and integrin beta 3 (ITGB3) were able to interact with more proteins and they were the key nodes in the signaling transduction. CONCLUSION: TGFBR1, SRC, MYC and ITGB3 might be the key points of RANKL and M-CSF induced differentiation of osteoclasts.

[An animal experiment of immediate construction of mandibular defect].

PURPOSE: To observe the effect of immediate construction of mandibular defect with or without teeth missing by bone composite and absorbable Bio-gide membrane. METHODS: 40 New Zealand rabbits were randomly divided into 3 groups. For the mandibular defect, group A was filled with nothing, group B was filled with bone composite and Bio-gide membrane, group C was filled with bone composite and Bio-gide membrane as well as autogenous tooth implantation. The rabbits were sacrificed 4,8,12 weeks after surgery for evaluation of gross morphology, X-ray and histopathology. RESULTS: After 12 weeks, the defect in group A was still there but narrower, the defect in group B was filled with new bone, the density of which was same to the bone X-ray, and lamellar bone were under microscope, the implanted teeth in group C had been fixed tightly in 17 animals, no transparent areas in 13 animals from X-ray, but absorbable areas in 13 animals under microscope were noted. CONCLUSIONS: Immediate construction of mandibular defect with bone composite and Bio-guide membrane is feasible and effective,autogeneous tooth implantation on the construction area is also stable.