BACKGROUND/OBJECTIVES: The immunomodulatory effect of Platycodon grandiflorum (PG) has been reported, but studies on its mechanism are still lacking. This study was undertaken to confirm whether the ...hydrolyzed and fermented PG extract (HFPGE) obtained by adding hydrolysis and fermentation to the extraction process has an immune-enhancing effect in the in vivo system. MATERIALS/METHODS: Five-week-old BALB/c mice were divided into 4 groups: normal control group (NOR), control group (CON), 150 mg/kg body weight (BW)/day HFPGE-treated group (T150), and 300 mg/kg BW/day HFPGE-treated group (T300). The mice were administered HFPGE for 4 weeks and intraperitoneally injected with cyclophosphamide (CPA, 80 mg/kg BW/day) on day 6, 7, and 8, respectively, to induce immunosuppression. The levels of immunoglobulins (Igs) and cytokines were measured in the serum. In splenocytes, proliferation and cytokine levels were measured. RESULTS: Serum IgA, IgG, and IgM levels were observed to decrease after CPA treatment, which was recovered by HFPGE administration. The levels of serum interleukin (IL)-12, tumor necrosis factor (TNF)-α, IL-8, and transforming growth factor (TGF)-β were also decreased after exposure to CPA but increased after HFPGE administration. Decreased splenocyte proliferation was seen in CPA-treated mice, but was observed to increase in the T150 and T300 groups as compared to the NOR group. Compared to the CON group, splenocyte proliferation stimulated with concanavalin A (ConA) or lipopolysaccharide (LPS) in the HFPGE-treated groups was significantly increased. The cytokines secreted by ConA-stimulated splenocytes (IL-2, IL-12, interferon-γ, TNF-α) were increased in the T150 and T300 groups, and cytokines secreted by LPS-stimulated splenocytes (IL-4, IL-8, TGF-β) were also increased by HFPGE administration. CONCLUSION: These results suggest that HFPGE stimulates the immunity in immunosuppressed conditions, thereby enhancing the immune response. Therefore, it is expected that HFPGE has the potential to be used as functional food and medicine for immune recovery in various immunocompromised situations.
미국의 패권이 유지되고 있는 21세기에 중국의 부상이 가져올 잠재적 위기 상황을 두고 우리가 “투키디데스의 함정(Thucydides’ Trap)”에 빠지는 것은 아닐까라는 표현이 줄곧 사용되고 있다. 고대 그리스 시기 도시국가인 아테네(Athens)는 당시패권을 장악하고 있던 다른 도시국가인 스파르타(Sparta)에 대항해 점차 세력을 확장하면서 대립 ...구도를 형성했다. 이러한 구조적 틀 안에서 스파르타가 느꼈던 두려움(fear)으로 인해 펠로폰네소스 전쟁(Peloponnesian War)이라는 대전쟁이 일어났음을 투키디데스가 전하고자 했다는 내용이 담긴 용어가 바로 ‘투키디데스의 함정’이다. 하지만 실제로 투키디데스는 저서 어디에서도‘함정’이라는 단어를 직접 사용하지 않았다. 이에 투키디데스가 말한 적이 없는 함정이라는 용어를 학자들은 어떻게사용하게 되었고, 그 쓰임은 적절한지를 묻는 일은 해당 용어를 언급하는 사례가 늘어남에 따라 필수적으로 수행되어야 할 것으로 판단된다. 이에 따라 본고는 ‘투키디데스의 함정’이라는 용어가 국제정치 분과에서 어떻게 사용되고 있는지 살펴보고, 투키디데스 저작에 대한 검토를 통해 이러한 사용이 적절한지를 논한다. 이를 통해(신)현실주의나 여타 국제정치이론에서 제시되는 것처럼 투키디데스는 전쟁 원인론을 밝히려는 저술 의도보다는 인간의 본성상 항시 내재할 수밖에 없는 두려움이라는요소를 부각하고자 했음을 지적하고자 한다. 이러한 검토에 더해 실질적으로 인간의두려움을 자극하는 요인은 인간의 무지인데, 인간은 이를 극복할 수 있다는 과도한자신감을 내세우며 위기를 맞닥뜨리게 된다는 가르침을 투키디데스가 전하고자 했다고 주장한다. 이러한 무지와 과도한 자신감으로 인해 전쟁의 씨앗이 심어졌고 여러차례 전쟁이 중단될 수 있었음에도 불구하고 전쟁이 계속되었던 모습을 그려냈다는것이다. 그리고 투키디데스는 결국 전쟁을 승리로 이끈 스파르타의 여러 지도자들을 소개하면서, 지도자의 성품과 지혜로 인해 도시국가가 어떠한 결과를 마주했는지를보여주자 했음을 강조할 것이다. 그리고 이러한 투키디데스의 가르침을 상기한다면, ‘무역 분쟁’을 지속하고 ‘COVID-19’ 바이러스 책임론을 떠넘기는 등 악화일로를 걷고 있는 미중 양국이 제3차 세계대전에 임박했다는 식의 공포를 조장하며 ‘함정’에빠지기 보다는, 합리적이라고 내린 판단이 여전히 불완전함을 깨닫고 주변국들과 좀더 원만한 관계를 유지하고자 하는 태도와 지혜를 갖출 것을 촉구하는 분위기가 형성되지 않을까 바라본다. In the 21st century, where the United States still overpowers every other country, the expression “Thucydides’ Trap” gains more currency since China rises on the world scene. In ancient Greece, against the hegemonic city-state Sparta, another city-state, Athens, who was gradually expanding its power, challenged Sparta’s status. The structural pressure, which both city-states is claimed to have been experienced, is termed “Thucydides’ Trap”. However, Thucydides did not use the word “trap” anywhere in his book. For what reason many scholars used the term, which Thucydides had never written? Is it appropriate using the term to explain his thought? Raising these questions, this paper examines the way the term “Thucydides’ Trap” has been used in the International Relations Division, and discusses whether such usage is appropriate. This paper is in line with the view that, contrary to what (neo)realism and other international political theories had assumed, Thucydides, rather than showing the cause of war, intended to emphasize the element of fear, inherent in human nature. In addition, it will argue both that such a fear is aroused by our ignorance, and that on the other hand, Thucydides attempted to problematize human arrogance. Both ignorance and excessive self-confidence were the seeds of provoking war; the war could have ended earlier or not even started without those. While explicating these factors, Thucydides also shows the way several leaders of Sparta, who eventually won the war, behaved during the war; he seemed to show the consequences of their wisdom and attitudes. Recalling Thucydides’ teaching, we, under the perilous situation where ‘trade dispute’ affects negatively on economic matters and ‘COVID-19’ virus threatens our daily life, would hope a way out from this stalemate. Rather than falling into the trap, we should realize our limit and seek a more amicable relationship with others. KCI Citation Count: 0
메탈폼 지지체를 이용한 액체연료 분해반응 촉매의 흡열특성 문정인; Jeongin Mun; 김나리 ...
Korean Chemical Engineering Research(HWAHAK KONGHAK), 59(4),
11/2021, Letnik:
59, Številka:
4
Journal Article
Recenzirano
Odprti dostop
극초음속 비행체의 비행 중에 발생되는 열 문제를 해결하기 위해 탑재된 연료의 분해반응 시 나타나는 흡열효과를 이용하는 냉각기술이 개발되고 있다. 본 연구에서는 HZSM-5를 촉매로 사용하여 n-dodecane 연료의 분해반응을 수행하였으며, 촉매 분해반응의 흡열효과를 극대화하고 코크생성을 억제하기 위해 촉매를 메탈폼에 코팅하였다. 반응기는 외경 1.27 ...cm의 스테인리스 스틸 흐름형 반응기를 사용하였다. HZSM-5를 메탈폼에 코팅한 촉매를 사용한 촉매 분해 반응 결과 흡열량은 최대 2887 kJ/kg, 기상전환율은 34% 이었으며, 메탈폼의 코크생성량은 촉매를 코팅함에 따라 촉매를 코팅하지 않은 것에 비해 약 56% 감소하였다.
In a hypersonic vehicle to solve the heat problem generated during flight, a cooling technology is being developed which uses the endothermic effect that appears during the decomposition reaction of the mounted fuel. In this study, the decomposition reaction of n-dodecane fuel was performed using HZSM-5 as a catalyst, and the catalyst was coated on metal foam to maximize the endothermic effect of the catalytic decomposition reaction and suppress coke formation. The reactor was a stainless steel flow reactor with a outer diameter of 1.27 cm, and the reaction temperature was 550 ℃, the reaction pressure was 4 MPa, and the flow rate was 12 ml per minute. As a result of the catalytic decomposition reaction using a catalyst coated with HZSM-5 on the metal foam, the heat sink was 2887 kJ/kg as a maximum, the gas phase conversion rate was 34%, and the amount of coke produced on the metal foam decreased by about 56% as the catalyst was coated compared to the uncoated catalyst.
Comparative genomic analysis was performed on eight species of lactic acid bacteria (LAB)― Lactococcus (L.) lactis, Lactobacillus (Lb.) plantarum, Lb. casei, Lb. brevis, Leuconostoc (Leu.) ...mesenteroides, Lb. fermentum, Lb. buchneri, and Lb. curvatus―to assess their glutamic acid production pathways. Glutamic acid is important for umami taste in foods. The only genes for glutamic acid production identified in the eight LAB were for conversion from glutamine in L. lactis and Leu. mesenteroides, and from glucose via citrate in L. lactis. Thus, L. lactis was considered to be potentially the best of the species for glutamic acid production. By biochemical analyses, L. lactis HY7803 was selected for glutamic acid production from among 17 L. lactis strains. Strain HY7803 produced 83.16 pmol/μl glutamic acid from glucose, and exogenous supplementation of citrate increased this to 108.42 pmol/μl. Including glutamic acid, strain HY7803 produced more of 10 free amino acids than L. lactis reference strains IL1403 and ATCC 7962 in the presence of exogenous citrate. The differences in the amino acid profiles of the strains were illuminated by principal component analysis. Our results indicate that L. lactis HY7803 may be a good starter strain for glutamic acid production.
We propose a new numerically stable sequential implicit method for coupled flow and finite-strain multiplicative elastoplastic geomechanics. We find from stability analysis that the sequential method ...that solves the flow problem first by fixing the first Piola–Kirchhoff total stress, solving the geomechanics (solid deformation) problem at the next step, is unconditionally stable (contractive and B-stable). In this sense, this method named the fixed first Piola–Kirchhoff stress method is an extension of the fixed stress method in coupled flow and infinitesimal geomechanics. We also study the fixed second Piola–Kirchhoff stress method, comparing it with the fixed first Piola–Kirchhoff stress method, because the constitutive relations are formulated by the second Piola–Kirchhoff total stress, although fixing the second Piola–Kirchhoff total stress field does not provide theoretical unconditional stability. In space discretization, we use the finite element method for the geomechanics problem with the total Lagrangian approach, while employing the finite volume method for the flow problem. Geometrical nonlinearity from the total Lagrangian approach results in full-tensor permeability even if the initial permeability is isotropic. To consider the full-tensor permeability accurately, we employ the multipoint flux approximation in solving the flow problem. In time discretization, the backward Euler method is used. Then, we perform numerical experiments of the two fixed-stress sequential methods with various scenarios, and find superiority of their numerical stability. Specifically, the two fixed-stress sequential methods provide almost identical results for elasticity. For J2 plasticity, the two sequential methods yield slightly different numerical results although the trends of the results are similar. For the Drucker–Prager plasticity, we find that the results from the two methods are almost identical. For all the test cases, the two sequential methods are numerically stable.
•New sequential method for largely deformable poromechanics.•Mathematical stability analysis of the proposed sequential method.•Straightforward implementation using existing simulators.•No need to update the mesh for flow and geomechanics.
BACKGROUND AND PURPOSE—The prediction of long-term outcomes in ischemic stroke patients may be useful in treatment decisions. Machine learning techniques are being increasingly adapted for use in the ...medical field because of their high accuracy. This study investigated the applicability of machine learning techniques to predict long-term outcomes in ischemic stroke patients.
METHODS—This was a retrospective study using a prospective cohort that enrolled patients with acute ischemic stroke. Favorable outcome was defined as modified Rankin Scale score 0, 1, or 2 at 3 months. We developed 3 machine learning models (deep neural network, random forest, and logistic regression) and compared their predictability. To evaluate the accuracy of the machine learning models, we also compared them to the Acute Stroke Registry and Analysis of Lausanne (ASTRAL) score.
RESULTS—A total of 2604 patients were included in this study, and 2043 (78%) of them had favorable outcomes. The area under the curve for the deep neural network model was significantly higher than that of the ASTRAL score (0.888 versus 0.839; P<0.001), while the areas under the curves of the random forest (0.857; P=0.136) and logistic regression (0.849; P=0.413) models were not significantly higher than that of the ASTRAL score. Using only the 6 variables that are used for the ASTRAL score, the performance of the machine learning models did not significantly differ from that of the ASTRAL score.
CONCLUSIONS—Machine learning algorithms, particularly the deep neural network, can improve the prediction of long-term outcomes in ischemic stroke patients.
본 논문에서는 전기자동차용 배터리 충/방전 상태 추정의 정확도를 개선하기 위해 칼만 필터(Kalman Filter, KF) 알고리즘과 등가회로모델(Equivalent Circuit Model)을 활용한 State Of Charge (SOC) 추정 방법을 적용하였다. 특히 노화된 배터리 용량을 함께 추정 가능한 관측기(observer)를 설계하였다. 우선 ...노화가 없는 경우, 칼만 필터를 이용하여 SOC를 단일 추정하면, 관측기 없이 모델로 계산된 경우와 비교하여 평균 절대 오차율이 1.43%(관측기 미사용)에서 0.27%(관측기 사용)로 감소하였다. 차량 주행상태에서는 전류가 고정되지 않아 SOC와 배터리 용량을 모두 추정하는 것에 일반적인 KF 혹은 Extended KF 알고리즘을 이용할 수 없다. 배터리 노화에 의한 용량 변화는 단시간에 일어나지는 않다는 점에 착안하여, 충전 시 배터리 용량 추정을 주기적으로 실시하는 전략을 제시하였다. 충전 모드에서는 일정 구간마다 전류가 고정되기에, 해당 상황에서 배터리 노화 용량을 SOC와 함께 추정 전략을 제시하였다. 전류가 고정된 상태에서 SOC 추정의 평균 절대 오차율은 0.54% 였으며, 용량 추정의 평균 절대 오차율은 2.24%로 나타났다. 충전상태에서 전류가 고정됨으로 일반적인 EKF를 활용하여 배터리 용량과 SOC 동시 추정이 가능하도록 하였다. 이를 통하여 배터리 충전 시 주기적인 배터리 용량 보정을 수행할 수 있다. 그리고, 방전 시에는 해당 용량으로 고정한 채 SOC를 추정하는, 배터리 관리 시스템에서 활용 가능한 추정 알고리즘을 제안하였다.
In this paper, an estimation algorithm for state of charge (SOC) was applied using an equivalent circuit model (ECM) and an Extended Kalman Filter (EKF) to improve the estimation accuracy of the battery system states. In particular, an observer was designed to estimate SOC along with the aged capacity. In the case of the fresh battery, when SOC was estimated by Kalman Filter (KF), the mean absolute percentage error (MAPE) was 0.27% which was smaller than MAPE of 1.43% when the SOC was calculated by the model without the observer. In the driving mode of the vehicle, the general KF or EKF algorithm cannot be used to estimate both SOC and capacity. Considering that the battery aging does not occur in a short period of time, a strategy of periodically estimating the battery capacity during charging was proposed. In the charging mode, since the current is fixed at some intervals, a strategy for estimating the capacity along with the SOC in this situation was suggested. When the current was fixed, MAPE of SOC estimation was 0.54%, and the MAPE of capacity estimation was 2.24%. Since the current is fixed when charging, it is feasible to estimate the battery capacity and SOC simultaneously using the general EKF. This method can be used to periodically perform battery capacity correction when charging the battery. When driving, the SOC can be estimated using EKF with the corrected capacity.
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