Chiang Mai Journal of Science

     In the present work, the characteristic of β-tricalcium phosphate (β-TCP) powder was investigated for its film coating on a Ti6Al4V metallic biomaterial. The β-TCP powder was synthesized by a solid-state reaction technique at different temperatures. The β-TCP formed at temperatures 900-1000 ^oC, while α-tricalcium phosphate (α-TCP) was occurred at higher temperatures (≥1000 ^oC). Crystallite size increased with increasing temperature, but it decreased at temperatures higher than 1000 ^oC due to the formation of α-TCP. Furthermore, the amount of α-TCP phase increased with temperature. However, maximum crystallite size and density values were found for the 1000 ^oC powder. The 1000 ^oC powder was coated on a titanium alloy (Ti6Al4V) by a dip coating technique. The coated surface presented a uniform grain with an average grain size of 3.21 μm. Bioactivity testing of the coated samples indicated that they had good bioactivity. The results indicate the possibility of developing the samples for biomedical applications.

     In the present work, ZnSe nanocrystals doped (NCs) with selenium (ZnSe:Se) were synthesized and characterized. The impact of the concentration of ZnSe:Se NCs nanocrystals on the properties of the Poly(3-hexylthiophene-2,5-diyl) (P3HT) matrix was studied with a collection of experimental and theoretical investigations of this organic-inorganic hybrid structure. The optical absorption spectra were found to be strongly dependent on the level of ZnSe:Se NCs. Theoretical analysis provided insight into the experimental data for the explanation of energy and charge transfer. The Benesi-Hildebrand diagram was use to prove the complex formation in our layers.

     Lotus (Nelumbo nucifera Gaertn.) is a species of aquatic plants in the Nelumbonaceae family. Currently, cultivation of ornamental flowers and breeding is widespread resulting in numerous hybrids and significant genetic diversity. Consequently, classification based on morphology becomes challenging and confusing. This research purposed to evaluate genetic diversity among nine samples in Phitsanulok province using sixteen qualitative and nine quantitative characters, along with three molecular markers: sequence-related amplified polymorphism (SRAP), random amplified polymorphic DNA (RAPD) and high annealing temperature random amplified polymorphic DNA (HAT-RAPD). The similarity index for the combined molecular markers ranged 0.736 to 0.990, while for morphological characteristics, it ranged from 0.440 to 0.920. Results from the molecular markers indicated that 5 SRAP, 7 RAPD and 8 HAT-RAPD primers produced an average of 38.2%, 40.2% and 28.8% polymorphic fragments per primer, respectively. The UPGMA cluster analysis based on molecular data and morphological traits grouped the Indochina Garden cultivars with those from Phitsanulok cultivars. Using the three molecular marker, seven cultivars in Phitsanulok province clustered together. In contrast, morphological characteristics separated into three groups. This suggested that two cultivars from the plant market were distinctly different from lotus cultivars in Phitsanulok province.

     The consumption of kombucha in Southeast Asia has risen significantly due to increasing awareness of wellness, leading to a high demand for novel beverages in the kombucha market. In this study, we focused on using dragon blood tea (Peristrophe bivalvis L. Merr), a local plant in Southeast Asia, as an alternative substrate for producing kombucha. The fermentation process was performed at 30°C for 15 days and compared with traditional kombucha made from green tea and black tea (Camellia sinensis L.). The microbiological properties of the three types of kombucha revealed similar growth patterns for both acetic acid bacteria and yeast. In terms of total phenolic content and antioxidant activity, green tea kombucha demonstrated the highest values, followed by dragon blood tea kombucha and black tea kombucha, respectively. Notably, dragon blood tea kombucha displayed a significant increase in total phenolic content throughout the fermentation period, whereas green tea and black tea kombucha exhibited a decrease after day 6 of fermentation. Antioxidant activity remained consistent across all types of kombucha during fermentation. Sensory evaluation revealed that dragon blood tea kombucha received the highest scores for appearance and color, although it scored lower in the aroma. These findings suggest the potential of dragon blood tea kombucha as a novel substrate for kombucha production, offering directions for future research, particularly focusing on enhancing aroma through the infusion of flowers or herbs.

       Limestone and calcined clay, due to their abundance and sustainability are seen as feasible materials to be used to replace Portland cement in the future. In this work, Portland cement was replaced with calcined clay and limestone at 50 % by weight. In addition to compressive strength, the microstructure and phase characterizations were investigated at 7 and 28 days to determine hydration and pozzolanic reaction of the mixes using thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. When using 20% calcined clay, the 50PC30LS20CC mix showed an increase in the compressive strength by 225% compared to the 50PC50LS mix. Although the compressive strength was still lower than 100 PC control mix, using calcined clay and limestone together lead to a significant reduction in the water absorption compared to 50% LS mix due to the phases formed and the filling effects, and comparable result to 100PC mix was found when calcined clay was used at 20%. In addition to calcium carbonate detected in mixes with limestone, monocarboaluminate phase was also found at 7 days and became clearer at 28 days, especially when there was a combination of calcined clay and limestone in the mix due to the presence of alumina from calcined clay. Moreover, pozzolanic reaction from the use of calcium clay resulted in the increase of C-S-H and C2ASH8 which increased with calcined clay content and corresponds with a reduction in calcium hydroxide and an increase in compressive strength.

     In this study, mung bean protein hydrolysates were prepared to evaluate their antioxidant properties under simulated conditions for food processing and in vitro digestion. Mung bean protein isolate, with a protein content of 93.6%, was hydrolyzed by Alcalase at 55 °C, pH 8, for 5-7 hours, using an enzyme-to-substrate ratio of 7%. The degree of hydrolysis (DH) was monitored during enzymatic treatment, reaching selected DH values of 50% and 55% after 360 and 420 minutes, respectively. Hydrolysates collected at 360 (H360) and 420 minutes (H420) demonstrated distinct antioxidant profiles, with H360 exhibiting optimal metal chelating activity (MCA) and ABTS radical scavenging activity. The stability of antioxidant protein hydrolysates derived from mung bean protein was evaluated under different incubation pH levels (4 and 6), at different temperatures (-18°C, 4°C, and 25°C for 24 hours; 63°C for 30 minutes; and 100°C for 5 minutes) and under in vitro digestion. Antioxidant properties were influenced by incubation pH, with higher ABTS scavenging activity observed at pH 6 compared to pH 4. However, MCA did not significantly differ between the two pH levels. Additionally, hydrolysates demonstrated thermal stability, retaining significant antioxidant activity after subjected to various temperature treatment. The hydrolysates also maintained or improved antioxidant capacity post simulated gastrointestinal digestion, highlighting their potential for functional food applications.