The purpose of this study is to develop a pH measurement system capable of measuring the acidity of saliva to check the change in pH level in saliva during driving and to detect whether fatigue is affected. When the pH level is checked at rest and operation, and oxygen concentration is supplied additionally, it will be verified whether the fatigue is reduced. It is reported that the pH level in saliva is divided into stages from 0 to 14, and the lower the value based on step 7, the higher the fatigue, and the lower the fatigue. In particular, in enclosed vehicles, drowsiness and fatigue due to increased carbon dioxide have increased, leading to a major cause of traffic accidents. Therefore, fatigue may be detected in advance by analyzing fatigue through a change in pH level by supplying oxygen during operation. The electromotive force generated by the existing itself is a level of several mV to develop a pH measurement system, so it is developed by expanding it to a range that can be measured using a readout circuit. In the experiment, 13 male experimenters in their 20s measured pH levels in resting and driving conditions. After 20 minutes of rest, the process of inhaling oxygen for 20 minutes was repeated three times. The oxygen concentration used in the experiment was 21% oxygen and 30% oxygen concentration in the atmospheric state, and in the oxygen supply method, a triangular flask was directly connected to the subject’s nose and then oxygen was supplied. As a result of collecting and analyzing saliva after rest and operation, it was confirmed that the pH level tended to decrease in the operating state. In addition, as a result of increasing the pH level when the oxygen concentration is 30% more than 21%, it is confirmed that fatigue tends to decrease as the oxygen concentration increases. Therefore, it was possible to confirm a significant change in fatigue by analyzing the pH level of saliva through this pH measurement system. This study can be used as a fatigue test in various environments through simple pH measurement.

The The purpose of this study is to establish evaluation criteria for the purchase of electric vehicles and to present an evaluation model using quantitative scales for evaluation factors. This study was limited to the study of purchasing factors related to electric vehicles, and the spatial scope was limited to potential buyers in their 20s to 50s living in the Daejeon area. Based on the survey, the factors affecting the purchase factors (energy economics, image, performance, maintenance, price) were examined using the AHP method, and the priorities were analyzed to determine how much influence these factors have on the purchase of electric vehicles. In addition, in order to verify the logical consistency of the survey items, a consistency ratio test (c) was conducted. Through this study, priority considerations for the purchase of electric vehicles were presented, and information on future consumer interest in electric vehicles was conducted. It is judged to be able to provide an opportunity to provide various services for each layer.

Human umbilical cord is easy to obtain because it is discarded after birth, so that ethical issues can be avoided. Chondrogenesis studies using MSCs from bone marrow, cord blood, and adipose have indicated that TGFβ3 and BMP6 stimulate chondrogenesis. Therefore, we investigated chondrogenesis of hUC-MSCs on TGFβ3, BMP6, and combination of the two growth factors. We initiated chondrogenesis of cells by application of physical forces to form 3D cell clusters. After initiation, we designated four experimental groups for differentiation of cells, as follows: control, 10 ng/mL TGFβ3, 100 ng/mL BMP6, and the combination of 5 ng/mL TGFβ3 and 50 ng/mL BMP6. For analysis of chondrogenesis, GAG contents, mRNA expression, histological analysis and immunohistochemistry (IHC) were performed. For analysis of GAG contents, GAG assay was performed and RT-PCR was performed for determination of chondrogenic markers. Histological analysis was performed through safranin O, alcian blue, and IHC was performed using collagen type I and II. GAG contents were increased 184% by TGFβ3, 147% by BMP6, and 189% by the combination of TGFβ3 and BMP6, compared to control. The growth factors improved collagen II and aggrecan expression; in particular, TGFβ3 and BMP6 showed a synergistic effect, compared to only TGFβ3 or BMP6 treated. The results of histological and IHC analysis indicated that chondrogenic differentiation in TGFβ3 and the combination of TGFβ3 and BMP6 showed more cartilage deposition. In conclusion, TGFβ3 and BMP6 differentiated hUC-MSCs into chondrogenic clusters of the combination treatment of the two growth factors showed more efficient chondrogenic ability.

The use of high throughput screening (HTS) in drug development is principally for the selection new drug candidates or screening of chemical toxicants. This system minimizes the experimental environment and allows for the screening of candidates at the same time. Umbilical cord-derived stem cells have some of the characteristics of fetal stem cell and have several advantages such as the ease with which they can be obtained and lack of ethical issues. To establish a HTS system, optimized conditions that mimic typical cell culture conditions in a minimal space such as 96 well plates are needed for stem cell growth. We have thus established a novel HTS system using human umbilical cord derived-mesenchymal stem cells (hUC-MSCs). To determine the optimal cell number, hUC-MSCs were serially diluted and seeded at 750, 500, 200 and 100 cells per well on 96 well plates. The maintenance efficiencies of these dilutions were compared for 3, 7, 9, and 14 days. The fetal bovine serum (FBS) concentration (20, 10, 5 and 1%) and the cell numbers (750, 500 and 200 cells/well) were compared for 3, 5 and 7 days. In addition, we evaluated the optimal conditions for cell cycle block. These four independent optimization experiments were conducted using an MTT assay. In the results, the optimal conditions for a HTS system using hUC-MSCs were determined to be 300 cell/well cultured for 8 days with 1 or 5% FBS. In addition, we demonstrated that the optimal conditions for a cell cycle block in this culture system are 48 hours in the absence of FBS. In addition, we candidates using our HTS system which demonstrates the feasibility if using hUC-MSCs for this type of screen. Moreover, the four candidate compounds can be tested for stem cell research application.

Endothelial cells are a vital constituent of most mammalian organs and are required to maintain the integrity of these tissues. These cells also play a major role in angiogenesis, inflammatory reactions, and in the regulation of thrombosis. Angiogenesis facilitates pulp formation and produces the vessels which are essential for the maintenance of tooth homeostasis. These vessels can also be used in bone and tissue regeneration, and in surgical procedures to place implants or to remove cancerous tissue. Furthermore, endothelial cell regeneration is the most critical component of the tooth generation process. The aim of the present study was to stimulate endothelial regeneration at a site of acute cyclophosphamide (CP)-induced endothelial injury by treatment with human umbilical cord-derived endothelial/mesenchymal stem cells (hEPCs). We randomly assigned 16 to 20-week-old female NOD/SCID mice into three separate groups, a hEPC (1 × 105 cells) transplanted, 300mg/kg CP treated and saline (control) group. The mice were sacrificed on days 5 and 10 and blood was collected via the abdominal aorta for analysis. The alanine transaminase (ALT), aspartate aminotransferase (AST), serum alkaline phosphatase (s-ALP), and albumin (ALB) levels were then evaluated. Tissue sections from the livers and kidneys were stained with hematoxylin and eosin (HE) for microscopic analysis and were subjected to immunohistochemistry to evaluate any changes in the endothelial layer. CP treatment caused a weight reduction after one day. The kidney/body weight ratio increased in the hEPC treated animals compared with the CP only group at 10 days. Moreover, hEPC treatment resulted in reduced s-ALP, AST, ALT levels compared with the CP only group at 10 days. The CP only animals further showed endothelial injuries at five days which were recovered by hEPC treatment at 10 days. The number of CD31-positive cells was increased by hEPC treatment at both 5 and 10 days. In conclusion, the CP-induced disruption of endothelial cells is recovered by hEPC treatment, indicating that hEPC transplantation has potential benefits in the treatment of endothelial damage.