Nano-Hydroxyapatite (nHA) was isolated from salmon bone by alkaline hydrolysis. The resulting nHA was characterized using several analytical tools, including thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), to determine the purity of the nHA sample. The removal of organic matter from the raw fish was confirmed by TGA. FT-IR confirmed the presence of a carbonated group and the similarities to synthetic Sigma HA. XRD revealed that the isolated nHA was amorphous. Microscopy demonstrated that the isolated nHA possessed a nanostructure with a size range of 6–37 nm. The obtained nHA interacted with mesenchymal stem cells (MSCs) and was non-toxic. Increased mineralization was observed for nHA treated MSCs compared to the control group. These results suggest that nHA derived from salmon is a promising biomaterial in the field of bone tissue engineering.

Gastric cancer is the second most common cause of cancer-related deaths in the world. In this study, a bioactive derivative of chitooligosaccharide, named gallic acid-grafted-chitooligosaccharide (G-COS), was evaluated for its capabilities against the proliferation of AGS human gastric cancer cells. It was found that G-COS treatment caused significant inhibition of gastric cancer cell growth at concentrations of 200 and 400 μg mL⁻¹. The anti-growth effect of G-COS in AGS cells was characterized using flow cytometry, fluorescence microscopy, DNA fragmentation and evaluation of protein expression. Notably, G-COS-induced apoptosis was related to the increase in the expression of p53, p21, Bax, and caspases (-9 and -3) and the decrease in the activation of Bcl-2, p-IκB-α and NF-κB (p50 and p65). These findings indicate that G-COS has potential to be applied in the treatment of gastric cancer as a cancer chemopreventative agent.

The performance of air conditioning systems deteriorate due to the natural aging and wear caused by operating the devices. This is termed “aging degradation,” and it results from a lack of appropriate maintenance which accelerates the degree of performance degradation. The performance degradation of an air conditioning system can cause problems such as increased energy consumption, deteriorated indoor heating environment, and shortened lifespan of air conditioning equipment. To prevent such problems, it is important to establish a long-term maintenance plan to recover degraded performance, such as predicting an appropriate maintenance time by identifying the real-time performance degradation rate based on a system’s operation data. In this study, the performance degradation rate, according to the operating time, was estimated using long-term operation data for devices constituting a heat source system, and the effect of performance degradation of the heat source system’s operation and energy consumption was reviewed using a simulation. The performance degradation rate of the target device was estimated by analyzing the variation trend of the calibration coefficient, which was calculated when the initial performance prediction model was calibrated through operating data. Using this approach, it was confirmed that the annual performance degradation rate was 1.0–1.4% for the heat source equipment, 0.4–1.2% for the cooling towers, and 0.8–1.3% for the pumps. In addition, a heat source system energy simulation calculated the 15-year performance degradation of the heat source equipment to be 34–52% and 7–19% for both the cooling towers and pumps. Due to the equipment performance deterioration, the number of operating heat source equipment and cooling tower fans, and the pump flow rate gradually increased every year, thus accelerating the performance deterioration even further. As a result, energy consumption in the 15th year increased by approximately 41% compared with the initial energy consumption.