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In this study, solution enhanced dispersion by supercritical fluids (SEDS) technique was applied for the preparation of 5-aminosalicylic acid (5-ASA) loaded Eudragit S100 (EU S100) nanoparticles. The effects of various process variables including pressure, temperature, 5-ASA concentration and solution flow rate on morphology, particle size, 5-ASA loading and entrapment efficiency of nanoparticles were investigated. Under the appropriate conditions, drug-loaded nanoparticles exhibited a spherical shape and small particle size with narrow particle size distribution. In addition, the nanoparticles prepared were characterized by X-ray diffraction, Differential scanning calorimetry and Fourier transform infrared spectroscopy analyses. The results showed that 5-ASA was imbedded into EU S100 in an amorphous state after SEDS processing and the SEDS process did not induce degradation of 5-ASA.

Bioorthogonal ligations have been designed and optimized to provide new experimental avenues for understanding biological systems. Generally, these optimizations have focused on improving reaction rates and orthogonality to both biology and other members of the bioorthogonal reaction repertoire. Less well explored are reactions that permit control of bioorthogonal reactivity in space and time. Here we describe a strategy that enables modular control of the cyclopropene-tetrazine ligation. We developed 3-N-substituted spirocyclopropenes that are designed to be unreactive towards 1,2,4,5-tetrazines when bulky N-protecting groups sterically prohibit the tetrazine's approach, and reactive once the groups are removed. We describe the synthesis of 3-N spirocyclopropenes with an appended electron withdrawing group to promote stability. Modification of the cyclopropene 3-N with a bulky, light-cleavable caging group was effective at stifling its reaction with tetrazine, and the caged cyclopropene was resistant to reaction with biological nucleophiles. As expected, upon removal of the light-labile group, the 3-N cyclopropene reacted with tetrazine to form the expected ligation product both in solution and on a tetrazine-modified protein. This reactivity caging strategy leverages the popular carbamate protecting group linkage, enabling the use of diverse caging groups to tailor the reaction's activation modality for specific applications.

The effects of microwave cooking on the changes of physical properties, protein denaturation, microstructure and volatiles of yak meat were investigated. Various microwave power settings were used for cooking the yak longissimus meats, and SDS-PAGE, cooking loss, colour difference, shear force, microstructure and volatile flavour compounds of longissimus muscle were evaluated. Cooking losses (37.03-45.92%) and shear forces (257.20-315.57 N) in microwave heated meats were higher and lower, respectively, than these in boiled meats (p < .05). Cooking loss, a* values, and shear force significantly (p < .05) increased as the prolonged microwave cooking time, while L* value decreased (p < .05) and more muscle fibres fractured and contracted. High power (700 W; 100%) microwave cooked yak meat had higher L* values, but lower a* values and shear force than meats cooked at medium (560 W; 80%) or low (420 W; 60%) settings. Significant higher cooking loss and volatiles were found in medium power cooked meats compared to high and low power groups. The results suggested that microwave cooking could yield yak meat product with better texture and volatiles attributes but higher cooking loss and decolorization compared to conventional boiling cooking, and maybe an applicable processing method to obtain high quality yak meat products.

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