Conventional aquaculture faces declining productivity, shifting to recirculating aquaculture system (RAS), known for minimizing water usage and maintaining consistent water temperatures for year-round fish growth. Rainbow trout (Oncorhynchus mykiss), a globally important cold-water species and the third most farmed fish in inland waters of Korea, valued for its fecundity and rapid growth. Dissolved oxygen, an important environmental factor affecting fish production and economics, highlights the need for smart aquaculture practices. Since 2018, the rise of intelligent aquaculture platforms, incorporating information and communications technology (ICT), emphasizes the essential role of RAS implementation. This eight-week study aimed to determine the optimal dissolved oxygen concentration for rainbow trout in RAS, utilizing a device for continuous monitoring, control and record. Dissolved oxygen concentrations were set at 5-6 mg/L, 9-10 mg/L, 14-15 mg/L and 17-18 mg/L. The growth rate significantly decreased at 5-6 mg/L, with no significant differences in other experimental groups. In hematological analysis, growth hormone (GH) was significantly highest at 5-6 mg/L, followed by 9-10 mg/L while Insulin-like growth factor-1 (IGF-1) was significantly lowest at 5-6 mg/L. In conclusion, the optimal dissolved oxygen concentration for rainbow trout in RAS is approximately 9-10 mg/L. Higher concentrations do not contribute to further growth or profitability.

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.

본 연구에서는 진해만의 DO 농도 재현을 목표로 LSTM 모형의 최적 매개변수 조건과 예측변수를 선별하기 위한 Case study를 진행하였다. 모형 매개변수 Case study 결과, 가장 적은 Hidden node와 Epoch인 Hidden node=10, Epoch=100에서 가장 낮은 정확도를 보였다. 이는 모형이 과소적합(Underfitting) 상태인 것으로 판단된다. Hidden node=80, Epoch=1200에서 R2 값은 0.99로 가장 높은 정확도를 보였다. 예 측변수 Case study 결과, 1개의 환경변수만을 예측변수로 사용한 Step 1에서 수온을 예측변수로 했을 때 저층 DO 농도 재현의 R2 값은 0.81 로 가장 높은 정확도를 보였다. 이후 2개의 환경변수를 사용한 Step 2에서는 수온과 SiO2를 예측변수로 했을 때 R2 값은 0.92로 수온만 사 용했을 때보다 정확도가 급격히 증가하였다. 이는 저층 DO 농도와 SiO2 농도간의 높은 상관성(=0.70)에 기인한 것으로 판단된다. 상기 결과로부터 진해만의 DO 농도 재현에 적합한 LSTM 모형의 매개변수와 예측변수를 찾을 수 있었다.

Mass mortality of mariculture fish due to high summer temperatures is a major issue in the mariculture industry in many coastal waters of Korea, yet measures to mitigate the impact are generally limited. We injected a micro-bubble of liquefied oxygen into the bottom of rockfish cages (about 6-8 m deep) in order to maximize the dispersal of micro-bubbled seawater and reduce fish mortality. The injection of low-temperature oxygen in micro-bubbles lowered the water temperature at the injection area by as much as 1℃ and increased dissolved oxygen concentration by 0.5 ppm. In early August, following a week with persistent high water temperature (above 28.5℃), there was an increase in fish mortality despite the micro-bubble system, which resulted in approximately 7% death of the total introduced fish population. However, this mortality appeared to be much lower than mortality reported in a neighboring mariculture facility (approximately 50% mortality). We also estimated the volume that can be recirculated with pumped seawater using a micro-bubble system. We suggest that this approach of injecting liquefied oxygen through a micro-bubble system may reduce fish mortality during high temperature periods.

In order to determine the location of average concentration and distribution status of dissolved oxygen in the rectangular aeration tank of the sewage treatment plant was analyzed and the difference of dissolved oxygen concentration was remarkable at each location. Compared with the computational fluid dynamics analysis, it was found that the results were consistent with the measurement results by showing the difference of dissolved oxygen concentration between the locations. Based on the measured data, the representative location of dissolved oxygen in aeration tank was selected by using statistical analysis method and the representative location was expressed in three-dimensional coordinates(LWH : 25%, 50%, 33%) from flow direction and left wall. Also the difference between the dissolved oxygen concentration at the actual measurement location and the average concentration value of the entire aeration tank was founded, and the equations for calibrating the automatic measurement data considering the actual measurement location were calculated.

Needle-like NiO protecting layers on NiCrAl alloy foam, used as support for hydrogen production, are introduced through electroplated Ni and subsequent microwave annealing. To improve the stability of the NiCrAl alloy foam, oxygen concentration of microwave annealing to form a needle-like NiO layer with good chemical stability and corrosion resistance is controlled in a range of 20 and 50 %. As the oxygen concentration increases to 50 %, needle-like NiO forms a dense coating layer on the NiCrAl alloy foam; this layer formation can be attributed to accelerated growth of the (200) plane. In addition, the increased oxygen concentration causes increased NiO/Ni ratio of the resultant coating layer on NiCrAl alloy foam due to improved rate of the oxidation reaction. As a result, the introduction of dense needle-like NiO layers formed at 50 % oxygen concentration improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the electrolyte and the foam. Thus, needle-like NiO can be proposed as a superb protecting layer to improve the chemical stability of NiCrAl alloy form.

In this study, the growth kinetics of sulfur oxidizing bacteria, Acidithiobacillus thiooxidans, and the effect of dissolved oxygen were determined in low pH conditions for the effective removal of high concentrations of hydrogen sulfide. A dual growth kinetic was applied to identify the microbial growth rate at different hydrogen sulfide and oxygen concentrations in the liquid. A modified Monod-Gompertz equation was deemed most appropriate to examine the growth kinetic parameters of A. thiooxidans. The half saturation constants of hydrogen sulfide and oxygen for the modified Monod-Gompertz equation were found to be 0.9 and 1.1 mg/L, respectively. In addition, a bioreactor model, where the Monod-Gompertz equation was modified, was applied to simulate dissolved oxygen concentrations required for the removal of hydrogen sulfide. As a result, the dissolved oxygen concentrations were 0.5, 1.0, 1.5, and 3.3 mg/L, which were necessary to remove hydrogen sulfide to less than 10 ppm at the influent concentrations of 100, 500, 1000 and 3000 ppm, respectively. The required minimum dissolved oxygen concentrations under various conditions including reactor volume, gas retention time, and microbial concentrations can be determined using the numerical model developed in this study.

This research was planned and executed to evaluate how the composition of Yack-sun (oriental diet therapy) tea can effect the health conditions of people who are suffering from diet-related diseases such as being overweight, obese and hyperlipidemic, by taking Yack-sun tea in a form of nutritional supplement with daily meals. We produced Kangjieum with Lycense Mill., Polygonum multflorum Thunb, Cassia tora L., Crataegus pinnatifida Bge and Salvia miltiorrhiza Bge. We evaluated the effects of this tea on serum lipids, on homocysteine concentration, and on active oxygen contents, oxidative stress by clinical practices. We have determined that this tea has a significant effect on decreasing body fat content, decreasing total cholesterol, decreasing LDL-cholesterol, and decreses triglyceride and homocysteine concentrations. In addition, blood active oxygen content and oxidative stress were significantly decreased. We think that scientific and objective evaluation was performed on the components of Kangjieum prescription. We concluded that we could apply the components, not only in a form of tea, but also in other forms of various foods. The information we received from this conclusion will be basic information on how we can apply oriental medicinal resources into other food and will be a steppingstone for medicinal herbs to place a foot in the field of functional food research, which already draws sizable attention world-wide.

In this study, it was observed through the ability of performing secondary tasks and baseline fetal heart rate how the supply of lavender, peppermint and highly concentrated oxygen (40%) affected distraction due to the performance of secondary tasks in the driving environment. Twelve male university students conducted secondary tasks while driving in the environments (6 in total) mixed and designed with oxygen concentration (21%, 40%) and the condition of odors (Normal, Lavender, Peppermint). The test was proceeded in order of stable state (5mins), driving (5mins), and secondary tasks (1min), and by extracting ECG data from every section by 30secs, the mean value of baseline fetal heart rate was calculated. As a result of analysis, in the ability of performing secondary tasks, a percentage of correct answers showed no difference in oxygen concentration and the condition of odors (p > 0.05). In performance completion time, a percentage of correct answers decreased showing a statistically significant difference in the condition of odors compared with the condition where odors were not provided (p < 0.05). As for baseline fetal heart rate, in the comparison between sections, while performing secondary tasks, it increased showing a significant difference compared with stable state and driving state (p < 0.05). The effect of interaction was observed in oxygen concentration and the condition of odors. When odors were not provided, baseline fetal heart rate decreased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05), however, when peppermint was provided, it increased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05). In conclusion, the fact that the condition of odors increased the ability of calculation, and when only the highly concentrated oxygen was provided, parasympathetic nerve system was activated, however, when highly concentrated oxygen was provided with peppermint at the same time, sympathetic nervous system (sns) was activated, which had a negative effect on the autonomic nervous system was drawn.

Human umbilical Mesenchymal Stem Cell(uMSC) has been known as one of major component to regenerate connective tissues such as bone, cartilage, fat and others. The effect of low(5%), normotensive(20%) oxygen and freezing-thawing damage on proliferation of uMSC were investigated. low oxygen concentration culture of uMSC resulted in enhanced proliferation significantly(p<0.05) than 20% of oxygen culture. After the freezing-thawing injury to uMSC, 5% oxygen culture showed marked proliferation of uMSC than that of 20% oxygen(p<0.05) in the 5th passage of uMSC. Expression of antioxidant enzymes such as superoxide anion 1 and glutathione peroxidase 1 appeared marked in 20% oxygen cultured uMSC, which suggest oxidative stress could induce less proliferation of uMSC. Above findings would suggest prolferation of uMSC in 5% of oxygen will give more yields.

The effect of oxygen on the shape memory characteristics in Ti-18Nb-6Zr-XO (X = 0-1.5 at%) biomedical alloys was investigated by tensile tests. The alloys were fabricated by an arc melting method at Ar atmosphere. The ingots were cold-rolled to 0.45 mm with a reduction up to 95% in thickness. After severe cold-rolling, the plate was solution-treated at 1173 K for 1.8 ks. The fracture stress of the solution-treated specimens increased from 450 Mpa to 880 MPa with an increasing oxygen content up to 1.5%. The fracture stress increased by 287MPa with 1 at% increase of oxygen content. The critical stress for slip increased from 430 MPa to 695 MPa with an increasing oxygen content up to 1.5 at%. The maximum recovery strain of 4.1% was obtained in the Ti-18Nb-6Zr-0.5O (at%) alloy. The martensitic transformation temperature decreased by 140 K with a 1.0 at% increase in O content, which is lower than that of Ti-22Nb-(0-2.0)O (at%) by 20 K. This may have been caused by the effect of the addition of Zr. This study confirmed that addition of oxygen to the Ti-Nb-Zr alloy increases the critical stress for slip due to solid solution hardening without being detrimental to the maximum recovery strain.

This study investigated changes in cognitive ability of intellectual and disability people by supplying two different condition of oxygen (21%, and 92%), during visual matching task. 10 males (average 28.7±4.7 years), and 13 females (average 34.1±7.2 years) in intellectual and disability people were selected as the subjects for this study. The each run consisted of four phases, i.e., Rest (2 min.), Adaptation (1 min.), Control (2 min.) and Task (2 min.). The analysis of cognitive performance with 92% oxygen administration when compared to 21% oxygen revealed that the response time decreased. This result supports the hypothesis that hyperoxic air increase oxygen saturation level in the blood, lead to more available oxygen to the brain, thus increase the ability of cognitive processing of intellectual and disability people.

Human gingival fibroblasts (hGFs) were reported to play an important role in inflammatory reactions to lipopolysaccharide (LPS) from P.gingivalis in the periodontal connective tissue. Although the biostimulatory effects of hyperbaric oxygen therapy, such as anti-inflammatory activity, have been reported, the pathological mechanism is not completely understood. This study examined the changes in the inflammatory cytokine profiles, which are produced after exposure to hyperbaric oxygen in P.gingivalis LPS-treated human gingival fibroblasts, and subsequently to examine the mitogen activated protein kinase (MAPK) pathway involved in cytokine production. Gingival fibroblasts with or without P.gingivalis LPS were exposed to hyperbaric oxygen, and the cytokine profiles in the supernatant were observed using a human inflammation antibody array. The expression of cyclooxyginase-2 (COX-2) protein, phosphorylation of extracellular signal-regulated kinase (ERK1/2), p38, and c-Jun-N-terminal kinase (JNK) MAPK by western blot analysis, and the amount of prostaglandin E2 (PGE2) in the supernatant by an enzyme-linked immunoassay were determined. COX-2 protein expression and PGE2productionwereincreasedsignificantlyintheP. gingivalis LPS-treated group, and were decreased by treating P. gingivalis LPS with hyperbaric oxygen. Treatment of P. gingivalis LPS in the gingival fibroblasts led an increase in the amount of pro-inflammatory-related cytokines interleukin-6 (IL-6) and IL-8 released, whereas hyperbaric oxygen inhibits the irrelease. Ananalysis of the MAPK signal transduction showed that hyperbaric oxygen induced a significant decrease in the level of P38 phosphorylation regardless of the presence or absence of LPS. In addition, hyperbaric oxygen promoted JNK phosphorylation, significantly in the presence of LPS. Hyperbaric oxygen can inhibit pro-inflammatory cytokines and mediate the MAPK signal pathway, and appears to be useful as an anti-inflammatory tool.

본 연구는 93% 고농도 산소의 세 가지 공급량(1L/min, 3L/min, 5L/min)에 대해 20대 및 60대의 혈중산소 포화도의 차이를 규명하고자 하였다. 20대 남자 10명(25.0±1.8세)과 여자 10명(23.7±1.9세), 60대 남자 10명(68.0±2.6세)과 여자 10명(65.5±3.1세)의 피험자를 대상으로 실험을 수행하였다. 1L/min, 3L/min, 그리고 5L/min의 유량 변화가 가능하면서 순도 93%의 산소 농도를 일정하게 유지 할 수 있는 산소 공급 장치(OXUS Co.)를 사용하였다. Pre-hyperoxia(5분), 93%의 Hyperoxia(10분), Post-hyperoxia(10분)의 세 단계의 순서로 실험이 진행되었고, 전 단계에서 혈중 산소 포화도가 측정되었다. 유량이 증가할수록 혈중 산소 포화도는 증가하였고, 60대보다 20대의 혈중 산소 포화도가 더 높았다. 안정 상태(Pre-/Post-hyperoxia)에 비해 고농도 산소를 공급한 Hyperoxia 구간에서 혈중 산소 포화도가 증가하였다. 그러나 고농도 산소 공급으로 20대에 비해 60대의 혈중 산소 포화도의 증가량이 더 컸다.

본 연구에서는 공간 과제 수행 시 21%의 산소 농도와 30%의 고농도 산소 공급이 변연계의 활성화에 어떠한 변화를 유발하는지 관찰하였다. 총 8명의 오른손잡이 남자 대학생을 본 연구의 실험 참여자로 선정하였다. 공간 과제를 수행하는 동안 3T MRI 를 이용하여 뇌기능 영상을 획득하였다. 실험은 21%의 일반 공기 중의 산소 농도와 30%의 고농도 산소를 각각 공급하면서 공간 인지 과제를 수행하는 두 개의 회기로 구성된다. 변연계를 대상이랑(cingulate gyrus), 시상(thalamus), 변연엽(limbic lobe), 시상하부(hypothalamus), 해마(hippocampus), 해마방회(parahippocampa gyrus), 편도(amygdala), 유두체(mammilary body)의 8 개의 영역으로 분리하여 뇌 활성화 영역을 비교하였다. 공간 과제 수행 시 두 가지 산소 농도에 따른 변연계의 활성화 영역은 거의 동일하였다. 그러나 21%의 산소 농도에 비해 30%의 고농도 산소 공급 시 대상이랑(cingulate gyrus)과 시상(thalamus) 영역에서 활성화가 증가하였다. 즉, 30%의 고농도 산소 공급 시 공간 인지 수행 능력의 증가는 공간 인지 처리와 관련이 있는 대뇌 피질 뿐만 아니라 시상(thalamus)과 대상이랑(cingulate gyrus) 같은 피질하 영역에서의 신경 활성화의 증가와도 관련이 있는 것으로 판단된다.

The purpose of this study was to examine differences between male and female in blood oxygen saturation due to 93% oxygen administration of the three levels (1L/min, 3L/min, 5L/min) Ten healthy male (25 0±1 8 years) and ten female (23 7±1 9 years) college

주요 엽채류 7종의 주년 안정생산을 위한 담액수경 재배 시 양액의 순환주기가 양액의 용존산소 농도, 엽채류의 생육, 그리고 식물영양소의 함량에 미치는 효과를 검토한 결과, 양액을 1일 10분 순환 처리구는 정식 13일 후 용존산소 농도가 급격하게 떨어지고 17일 후에는 2.8mg L-1, 20일 후에는 최저 1.5mg L-1까지 낮아졌다. 처리 20일 후 7가지 엽채류의 생체중은 1일 10분 처리구에서는 대조구인 10분 순환/110분 정지 처리구에 비해 0~24% 범위에서 낮아졌으며, 10분 순환/10분 정지 처리구에서는 -2~34% 증가하였다. 양액의 순환주기가 짧을수록 식물체 엽내 P의 함량이 증가하였으며, 식물체의 C/N율과 비타민 C 함량은 감소하였다. 이상의 결과, 담액수경 엽채류의 안정적인 생육과 식물영영소의 흡수를 위해서 2시간에 10분 정도의 양액 순환 처리가 효율적이었다.