Influence of low-cost Thai leucoxene minerals on the growth, bioactive compounds, and antibacterial activities of Chrysanthemum indium L. cuttings in in vitro culture.

The effects of low-cost Thai leucoxene mineral (LM) at different concentrations (10, 20, 30, 40, 50, and 60 mg/L) on the growth and antibacterial properties of Chrysanthemum indium L. cuttings under in vitro were evaluated. The primary chemical composition of LM was approximately 86% titanium dioxide (TiO2), as determined by dispersive X-ray spectroscopy. The crystalline structure, shape, and size were investigated by X-ray diffraction and scanning electron microscopy. LM at 40 and 50 mg/L significantly increased plant height, leaf number, node number, and fresh and dry weight. These growth-promoting properties were accompanied by improved chlorophyll and carotenoid contents and antioxidant enzyme activities and reduced malondialdehyde levels. Additionally, LM treatment at 40 and 50 mg/L had positive effects on antibacterial activity, as indicated by the lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. The high levels of phenolic compounds in the plants contributed to the MIC and MBC values. In conclusion, these findings provide evidence for the effectiveness of LM in enhancing the growth of Chrysanthemum plants in in vitro culture and improving their antibacterial abilities.

Impact of pretreatment with dielectric barrier discharge plasma on the drying characteristics and bioactive compounds of jackfruit slices.

BACKGROUND: Hot-air drying is a popular method for preserving the production of jackfruit, but heat treatment damages its nutritional qualities. Cold plasma is one of the pretreatment methods used to preserve quality attributes of fruits before drying. In the present work, we studied the effect of dielectric barrier discharge (DBD) plasma on the drying characteristics, microstructure, and bioactive compounds of jackfruit slices with different pretreatment times (15, 30, 45, and 60 s), followed by hot-air drying at 50, 60, and 70 °C. A homemade DBD device was operated via three neon transformers. RESULTS: Optical emission spectrophotometry revealed the emitted spectra of the reactive species in DBD plasma, including the N2 second positive system, N2 first negative system, nitrogen ion, and hydroxyl radical. The results showed that the DBD plasma promoted moisture transfer and enhanced the drying rate, related to the changes in the surface microstructure of samples damaged by DBD plasma. The modified Overhults model was recommended for describing the drying characteristics of jackfruit slices. The contents of ascorbic acid, total phenolics, total flavonoids, total polysaccharides, and antioxidant activity in pretreated jackfruit slices were improved by 9.64%, 42.59%, 25.77%, 27.00%, and 23.13%, respectively. However, the levels of color and carotenoids were reduced. CONCLUSION: Thus, the bioactive compounds in dried jackfruit slices can be improved using the DBD plasma technique as a potential pretreatment method for the drying process. © 2023 Society of Chemical Industry.

Investigation on the physical properties and biocompatibility of zirconia-alumina-silicate@diopside composite materials and its in vivo toxicity study in embryonic zebrafish.

Bioceramic materials have a wide range of applications in the biomedical field, such as in the repair of bone defects and dental surgery. Silicate-based bioceramics have attracted biomedical researchers' interest due to their bioactivity and biodegradability. In this study, extended the scope of ZAS utilization in bone tissue engineering by introducing calcium-magnesium-silicate (diopside, CMS) as an interface material aim to develop a machinable bioceramic composite (ZASCMS) by the sol-gel method. The physicochemical characterization, in vitro biological properties and in vivo zebrafish cytotoxicity study of ZAS-based composites as a function of CMS contents, 0, 25, 50, 75 and 100 wt%, were performed. Results showed that the as-prepared ZASCMS possessed porous architecture with well-interconnected pore structure. Results also revealed that the mechanical properties of ZASCMS composite materials were gradually improved with increasing CMS contents. The ZASCMS composites with more than 50 wt% CMS had the highest compressive strength and modulus of 6.78 ± 0.62 MPa and 340.10 ± 16.81 MPa, respectively. Regarding in vitro bioactivities, the composite scaffolds were found to stimulate osteoblast-like UMR-106 cell adhesion, growth, and proliferation. The antibacterial activity of the ZASCMS composite scaffolds was tested against Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli) also exhibited an antibacterial property. Furthermore, the in vivo studies using embryonic zebrafish were exposed to as-prepared particles (0-500 µg mL-1) and showed that the synthesized ZAS, CMS and ZASCMS composite particles were non-toxic based on the evaluation of survivability, hatching rate and embryonic morphology. In conclusions, our results indicated that the synthesized composite exhibited their biological properties and antibacterial activity, which could well be a promising material with high potential to be applied in orthopaedic and dental tissue engineering.

Twisted scroll wave dynamics: partially pinned waves in excitable chemical media.

We present an investigation of the dynamics of scroll waves that are partially pinned to inert cylindrical obstacles of varying lengths and diameters in three-dimensional Belousov-Zhabotinsky excitable media. Experiments are carried out in which a scroll wave is initiated with a special orientation to be partially pinned to the obstacle. Numerical simulations with the Oregonator model are also carried out, where the obstacle is placed in the region of the core of a preexisting freely rotating scroll wave. In both cases, the effect of the obstacle on the wave dynamics is almost immediately observable, such that after the first revolution of the wave, the pinned region of the scroll wave has a longer period than that of the freely rotating scroll wave. The dependence of the scroll wave period on the obstacle position gives rise to a transition from a straight scroll wave to a twisted scroll wave in the pinned region, while the form of the freely rotating wave remains unchanged. The twisted scroll wave arises from the interaction of the freely rotating scroll wave with the obstacle, giving rise to a pinned twisted wave with the same period. The twisted scroll wave gradually advances, displacing the slower untwisted scroll wave until the scroll wave helically wraps around the entire obstacle. At this point, the period of the entire wave has a single value equal to that of the freely rotating scroll wave. The time for the transition to the twisted wave structure increases when either the obstacle length is increased or the obstacle diameter is decreased, while the average speed of the development increases with both the obstacle length and diameter. After the transition, the twisted wave remains stable, with its structure depending on the obstacle diameter - the larger the diameter, the shorter the helical pitch but the higher the twist rate.

Propagation of spiral waves pinned to circular and rectangular obstacles.

We present an investigation of spiral waves pinned to circular and rectangular obstacles with different circumferences in both thin layers of the Belousov-Zhabotinsky reaction and numerical simulations with the Oregonator model. For circular objects, the area always increases with the circumference. In contrast, we varied the circumference of rectangles with equal areas by adjusting their width w and height h. For both obstacle forms, the propagating parameters (i.e., wavelength, wave period, and velocity of pinned spiral waves) increase with the circumference, regardless of the obstacle area. Despite these common features of the parameters, the forms of pinned spiral waves depend on the obstacle shapes. The structures of spiral waves pinned to circles as well as rectangles with the ratio w/h∼1 are similar to Archimedean spirals. When w/h increases, deformations of the spiral shapes are observed. For extremely thin rectangles with w/h≫1, these shapes can be constructed by employing semicircles with different radii which relate to the obstacle width and the core diameter of free spirals.

Influence of excitability on unpinning and termination of spiral waves.

Application of electrical forcing to release pinned spiral waves from unexcitable obstacles and to terminate the rotation of free spiral waves at the boundary of excitable media has been investigated in thin layers of the Belousov-Zhabotinsky (BZ) reaction, prepared with different initial concentrations of H_{2}SO_{4}. Increasing [H_{2}SO_{4}] raises the excitability of the reaction and reduces the core diameter of free spiral waves as well as the wave period. An electric current with density stronger than a critical value Junpin causes a pinned spiral wave to drift away from the obstacle. For a given obstacle size, Junpin increases with [H_{2}SO_{4}]. Under an applied electrical current, the rotation center of a free spiral wave drifts along a straight path to the boundary. When the current density is stronger than a critical value Jterm, the spiral tip is forced to hit the boundary, where the spiral wave is terminated. Similar to Junpin for releasing a pinned spiral wave, Jterm also increases with [H_{2}SO_{4}]. These experimental findings were confirmed by numerical simulations using the Oregonator model, in which the excitability was adjusted via the ratio of the excitation rate to the recovery rate of the BZ reaction. Therefore, our investigation shows that decreasing the excitability can facilitate elimination of spiral waves by electrical forcing, either in the presence of obstacles or not.

Unpinning of spiral waves by electrical forcing in excitable chemical media.

We present experimental observations on the electrically forced release of spiral waves pinned to unexcitable circular obstacles in the Belosov-Zhabotinsky reaction. When the applied electric current density reaches the necessary current density J(unpin), the spiral tip is detached and subsequently drifts away from the obstacle. J(unpin) is found to increase with the obstacle diameter d. The growth rate ΔJ(unpin)/Δd is much higher for obstacles larger than the free spiral core compared to that for smaller obstacles. The experimental findings are confirmed by numerical simulations using the Oregonator model. The results imply that it is more difficult to release spiral waves pinned to larger obstacles, especially when the obstacle size exceeds that of the free spiral core.