[6]-Gingerol-loaded cellulose acetate electrospun fibers as a topical carrier for controlled release

[6]-Gingerol (6 % w/v)-loaded cellulose acetate (12 % w/v CA; MW ~ 3 × 10⁴ g/mol) fibers (375 ± 107 nm) were prepared by electrospinning at 7.5 kV. ATR-FTIR spectra indicated that the mixture was miscible at this composition. Differential scanning calorimetry revealed that [6]-gingerol was uniformly dispersed in the CA matrix and interrupted the hydrogen bond formation among the CA chains. Controlled release study showed that ~97 % of the loaded [6]-gingerol could be released from the loaded fibers to the acetate buffer solution at 37 °C, whereas only ~74 % of it could be done from the corresponding films. About 92 % of [6]-gingerol in the fibers was dramatically released within 4 h. Release was mainly governed by a diffusion-controlled mechanism. The radical scavenging assay showed antioxidant activity of the loaded fibers. The in vitro cytotoxicity test revealed that the viability of L-929 mouse fibroblast cells to the loaded fibers was ~65 %.     

Influences of phase transition and microstructure on dielectric properties of Bi<Subscript>0.5</Subscript>Na<Subscript>0.5</Subscript>Zr<Subscript>1-x</Subscript>Ti<Subscript>x</Subscript>O<Subscript>3</Subscript> ceramics

Bismuth sodium zirconate titanate ceramics with the formula Bi_0.5Na_0.5Zr_1-xTi_xO₃ [BNZT], where x = 0.3, 0.4, 0.5, and 0.6, were prepared by a conventional solid-state sintering method. Phase identification was investigated using an X-ray diffraction technique. All compositions exhibited complete solubility of Ti⁴⁺ at the Zr⁴⁺ site. Both a decrease of unit cell size and phase transition from an orthorhombic Zr-rich composition to a rhombohedral crystal structure in a Ti-rich composition were observed as a result of Ti⁴⁺ substitution. These changes caused dielectric properties of BNZT ceramics to enhance. Microstructural observation carried out employing SEM showed that average grain size decreased when addition of Ti increased. Grain size difference of BNZT above 0.4 mole fraction of Ti⁴⁺ displayed a significant increase of dielectric constant at room temperature.     

Phase,microstructure and ferroelectric properties of new complex-structured ferroelectric ceramics in the PZT–SBN system

This study aimed to fabricate and characterize new complex-structured ceramics with formula (1-x)Pb(Zr_0.52Ti_0.48)O₃–xSrBi₂Nb₂O₉ or (1-x)PZT–xSBN (where x=0, 0.1, 0.3 and 0.5 weight fraction). The ceramics were prepared by a solid-state mixed-oxide method and sintered at temperatures between 1000 and 1250 °C. Optimum sintering temperature for this system was found to be 1050 °C for 3 h dwell time. X-ray diffraction patterns of (1-x)PZT–xSBN powders showed peak intensities of two-phase mixture corresponding to the relative amount of each phase as a result of SBN addition. Microstructure of (1-x)PZT–xSBN ceramics showed a variation in grain shape and grain size. The small addition of SBN (x=0.1) was also found to improve ferroelectric properties of pure PZT ceramic.     

Effects of sintering temperature on microstructure and electrical properties of 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 modified with CuO

The structural, dielectric and ferroelectric properties of Pb(Mg_1/3Nb_2/3)_0.9Ti_0.1O₃ (PMNT) ceramics prepared with CuO as a sintering aid at various sintering temperatures between 950 °C and 1150 °C are investigated. The lattice parameters slightly increase with the sintering temperature >1050 °C. A significant increase in the grain size is observed when the sintering temperature is increased from 1000 °C to 1050 °C. The maximum dielectric constant reaches the highest value of ∼22,000 for the ceramic sintered at 1050 °C. For the ceramics sintered at >1050 °C, the temperature of maximum dielectric constant and the diffuseness parameters tend to increase with the increasing sintering temperature. The optimal sintering temperature for this ceramic is 1050 °C, which displays significant improvements in ferroelectric properties at room temperature, i.e. the increase in the remanent polarization and the ferroelectric loop squareness.     

Lead‐Free (Ba0.70Sr0.30)TiO3‐Modified Bi0.5(Na0.80K0.20)0.5TiO3 Ceramics with Large Electric Field–Induced Strains

The dielectric, ferroelectric, and electric field–induced strain behavior of Bi_0.5(Na_0.80K_0.20)_0.5TiO₃ (BNKT) ceramics modified with (Ba_0.70Sr_0.30)O₃ (BST) were investigated as a function of composition and temperature. The ceramic samples were synthesized by a solid‐state mixed oxide method and sintered at 1125°C for 2 h. The XRD and Raman spectra showed coexisting rhombohedral and tetragonal phases throughout the entire compositional range with the tetragonal phase becoming dominant at higher BST concentrations. For all compositions, the temperature dependence of the dielectric spectra revealed a frequency dependence that is characteristic of a relaxor mechanism. This suggests that these ceramics lacked long‐range order and it appears that the maximum disorder was observed for the composition with 5 mol% BST (BNKT–0.05BST sample). This was evidenced by the observation of pinched hysteresis loops, even at room temperature, and a significant decrease in the P_r and E_c values which resulted in large electric field–induced strains (S_max) of 0.40% and a normalized strain coefficient ( = S_max/E_max) of 732 pm/V. This significant strain enhancement at the composition of x = 0.05 may be attributed to both a composition‐induced structural phase transition and a field‐induced relaxor to ferroelectric phase transition.     

Physical and electrical properties of Nb doped Bi0.5Na0.5[Zr0.59Ti0.41]O3

This research studied the effect of Nb doping on Bi_0.5Na_0.5[Ti_0.41Zr_0.59]O₃ (when Nb concentration = 0.00, 0.01, 0.03, 0.05, 0.07 and 0.09 mol fraction). Nb doped BNTZ ceramics were fabricated using a conventional mixed-oxide method. All samples were calcined at a temperature of 700 °C for 2 h and sintered at a temperature of 900 °C for 2 h. X-ray diffraction patterns suggested that the compounds possessed rhombohedral perovskite structure. SEM micrographs indicated that average grain size decreased as the amount of Nb additives increased. The electrical resistivity showed a decreasing trend with increasing Nb concentration due to excess charge present in the sample. The dielectric constant and dielectric loss of samples showed no particular trend when Nb was added but the optimum was observed when 0.05–0.07 Nb mol fraction was present in BNTZ ceramics. In this study, both microstructure and donor-type effects played an important role in determining electrical resistivity and dielectric properties of these ceramics.     

Ferroelectric properties of Pb(Zr0.52Ti0.48)O3–Bi3.25La0.75Ti3O12 ceramics

The ceramic samples of compound (1 ? x)Pb(Zr_0.52Ti_0.48)O₃–xBi_3.25La_0.75Ti₃O₁₂ (when x = 0, 0.03, 0.05, 0.07, 0.10, 0.15 and 0.20) were prepared by a solid-state mixed oxide method. X-ray diffraction analysis showed that complete solid solutions occurred for all compositions. Perovskite phase with tetragonal crystal structure and corresponding lattice distortion was observed. Scanning electron micrographs of sample surfaces showed equiaxed grains for all compositions. Ferroelectric measurements revealed that the addition of small amount of BLT (x = 0.03) showed high remanent polarization (～33.5 μC cm^?2) and low coercive field (～2.74 kV mm^?1). Further increasing BLT content could maintain ferroelectric properties of PZT–BLT ceramics. Based on this study, ferroelectric properties of this PZT–BLT ceramic system can be improved for being further used in ferroelectric memory applications.     

Pyrolysis GC-MS-based metabolite fingerprinting for quality evaluation of commercial Angelica acutiloba roots

Metabolite fingerprinting was applied in the attempt to evaluate the quality of Angelica acutiloba dried roots (Yamato-toki). A pyrolyser coupled to a gas chromatography mass spectrometer (PY-GC-MS) was used to obtain higher chemical universality by analyzing whole compounds including high molecular weight metabolites. The machine was relatively fast and easy to use, with no sample preparation procedure required. Multivariate pattern recognition methods, specifically principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA), were successful in discriminating various toki samples. In addition, an enhanced understanding of the dominant relationship of cultivation area to quality evaluation was conceptualized and therefore applied to the construction of a PLS-DA classification model which provided the basis for accurate and reliable predictivity.     

Structure-property relations of co-doped bismuth layer-structured Bi3.25La0.75(Ti1-xMox)3O12 ceramics

In this work, the fabrication and investigation of substituting higher-valence Mo⁶⁺ for Ti⁴⁺ ion on the B-site of La³⁺-doped Bi₄Ti₃O₁₂ [BLT] structure to form Bi_3.25La_0.75(Ti_1-x Mo _x )₃O₁₂ [BLTM] (when x = 0, 0.01, 0.03, 0.05 0.07, 0.09, and 0.10) ceramics were carried out. X-ray diffraction patterns of BLTM ceramics indicated an orthorhombic structure with lattice distortion, especially with a higher concentration of a MoO₃ dopant. Microstructural investigation showed that all ceramics composed mainly of plate-like grains. An increase in MoO₃ doping content increased the length and thickness of the grain but reduced the density of the ceramics. Electrical conductivity was found to decrease, while the dielectric constant increased with Mo⁶⁺ doping concentration. Ferroelectric properties were found to be improved with increasing MoO₃ content and were optimized at x = 0.1.     

Effects of ZnO nanoparticulate addition on the properties of PMNT ceramics

This research was conducted in order to study the effect of ZnO nanoparticulate addition on the properties of 0.9 Pb(Mg_1/3Nb_2/3)O₃-0.1PbTiO₃ [PMNT] ceramics. The PMNT ceramics were prepared by a solid-state reaction. The ZnO nanoparticles were added into PMNT ceramics to form PMNT/xZnO (x = 0, 0.05, 0.1, 0.5, and 1.0 wt.%). The PMNT/xZnO ceramics were investigated in terms of phase, microstructure, and mechanical and electrical properties. It was found that the density and grain size of PMNT ceramics tended to increase with an increasing amount of ZnO content. Moreover, a transgranular fracture was observed for the samples containing ZnO, while pure PMNT ceramics showed only a intergranular fracture. An addition of only 0.05 wt.% of ZnO was also found to enhance the hardness and dielectric and ferroelectric properties of the PMNT ceramics.