Choline chloride based deep eutectic solvents for the lignocellulose nanofibril production from Mongolian oak (Quercus mongolica)

Cellulose - Lignocellulose nanofibrils (LCNFs) were produced from the biomass of Mongolian oak for the first time using deep eutectic solvent pretreatment and mechanical defibrillation. Three...     

α-Tocopherol-loaded Ca-pectinate microcapsules: Optimization, in vitro release, and bioavailability

We used response surface methodology to optimize microcapsule preparation conditions, including the ratio of pectin:α-tocopherol (TP) (X₁), emulsifier concentration (X₂), and CaCl₂ concentration (X₃) for maximal entrapment efficiency (EE) of TP-loaded Ca-pectinate microcapsules. The values of X₁, X₂, and X₃, optimized for maximal EE were a ratio of 9.7:6.3, and 1.33% and 5.09%, respectively. The experimental results obtained from the optimum formulation agreed with the predicted results, indicating the usefulness of models for EE. TP release from the Ca-pectinate microcapsules prepared according to the optimized conditions was slow and incomplete in simulated gastric fluid, whereas it was relatively rapid and considerably sustained in simulated intestinal fluid. An in vivo release study revealed that physical entrapment of TP within Ca-pectinate microcapsules can be a good technique to demonstrate the sustained release pattern of TP and to improve the bioavailability for TP following oral administration.     

γ-Oryzanol-loaded calcium pectinate microparticles reinforced with chitosan: Optimization and release characteristics

The cationic surfactant, cetyltrimethyl ammonium bromide (CTAB) effect on accurate determination of dopamine in the presence of ascorbic acid (as natural obtrusive in determination of dopamine) using chemically modified electrode based on tin hexacyanoferrate (SnHCF) as a modifier at carbon paste electrode (CPE) is described. The electrochemical response of bare CPE and SnHCF modified electrode (ME) examined in different pHs, in absence and presence of different concentration of dopamine (DA) and ascorbic acid (AA). In addition a simple and reliable method for simultaneous electrochemical determination of AA and DA was presented. It was based on the use of the cationic surfactant CTAB that enables the separation of the oxidation peaks potential of AA and DA. The experimental results showed that DA and AA have two separate peaks. In pH 3 and at presence of 3 mM of CTAB the separation of DA and AA peaks and the eminence of them increased evidently. Good linear response to AA and DA was observed in the range of 0.4–50 and 0.2–25 mM with the correlation of 0.9912 and 0.9955, respectively.     

Ultrathin carbon support films for high-resolution electron microscopy of nanoparticles.

We introduce a simple preparation method for ultrathin carbon support films that is especially useful for high-resolution electron microscopy (HREM) of nanoparticles. Oxidized iron nanoparticles were used as a test sample in a demonstration of this method. The film qualities are discussed on the basis of electron-energy-loss spectroscopy (EELS) and image analysis techniques such as thickness maps and histograms. We carried out a comparison between the homemade and commercial film qualities. The relative thickness of the homemade support films was 0.6 times less than that of the commercial films, which was calculated from the EELS analysis, whereas the thicknesses of both carbon support films varied within about 3%. The percentage of the observable area was about 67 +/- 7.6% of the support film. This was about twice as large as the commercial film (32 +/- 9.3%). The HREM image of the sample prepared with our support film improved 9% in brightness and 15% in contrast compared with images obtained with the commercial support.     

Characteristics and antioxidant activity of catechin-loaded calcium pectinate gel beads prepared by internal gelation

Catechin-loaded calcium pectinate gel beads prepared by internal gelation were characterized for their catechin entrapment efficiency and release behavior. The entrapment efficiency was higher when the beads were prepared with a lower catechin-to-pectin ratio, shorter gelling time, higher pectin concentration, and lower acetic acid concentration. The entrapment efficiency was much higher under all tested conditions, when the beads were prepared by internal gelation instead of external gelation. The catechin release was slower for the beads prepared with lower catechin-to-pectin ratio, longer gelling time, and higher concentrations of pectin and acetic acid in both simulated gastric and intestinal fluids. Antioxidant power of catechin was effectively maintained in alkaline simulated intestinal fluid when catechin was entrapped within the beads, compared to cases where it was not entrapped, indicating that the beads can protect catechin molecules from the alkaline environment and release them in a sustained fashion.