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Effect of Oxybenzone (Benzophenone-3) on Embryo Development in the Shimofuri Goby, Tridentiger bifasciatus
No full textOxybenzone (Benzophenone-3; BP-3) is used as a component of sunscreens, and known to disrupt the endocrine system of marine organisms. This study evaluated BP-3 toxicity on Shimofuri goby (Tridentiger bifasciatus). We evaluated morphological changes during embryogenesis. In addition, hatching rate (HR) and embryo survival to hatching were assessed. Embryos were exposed to BP-3 in artificial seawater, and then they were randomly sampled every 12 hours for microscopic observation and cortisol analysis. 36 hours after exposure to BP-3 100 and 1,000 μg/L groups, the tail was not separated from the yolk sac. 72 hours after exposure, incompleted eye pigmentation was observed at 100 and 1,000 μg/ L BP-3. After 48 and 60 hours of exposure, all individuals in the control group had elongated tails, whereas individuals in the all BP-3 treated group failed to elongate or showed signs of bent tails. Survival rate decreased dose-dependently (control: >90%) with LC50-96h=493 μg/ L. HR significantly declined in all BP-3 groups in a dose-dependent manner. And, heartbeat was increased in response to BP-3 1,000 μg/L. High levels of cortisol were observed in the initial groups (0 hours) and decreased after 24 hours. The BP-3 100 and 1,000 μg/L showed significantly lower cortisol levels than the control at 96 hours of exposure. Overall, this study suggests that BP-3 can interfere with embryonic development, resulting in adverse effects on survival and HRs in T. bifasciatus embryos.22Nkc
Environmental contour correction using Bayesian inference for areas with limited metocean data
No full textWind speed–wave height contours are crucial for evaluating the extreme metocean conditions of offshore wind structures. To construct reliable contours, long-term buoy data are essential. However, in Korea, the limited observation period of simultaneous wind and wave data poses a challenge, resulting in low reliability in estimating extreme environmental loads. Therefore, in this study, we proposed a method for refining the distribution of metocean data using Bayesian inference. Our comparison of extreme metocean conditions based on different observation periods revealed significant variations in the estimated conditions over short observation periods. To address this issue, the wave buoy data distribution was defined as a prior distribution, and the wave height distribution for the target region was corrected using a Bayesian inference approach. In addition, the wind speed distribution was improved by considering the correlation between wind speed and wave height. Subsequently, extreme metocean conditions were evaluated using the environmental contour approach based on the IFORM method. The results confirmed that the distribution of metocean data was improved, allowing for the derivation of more reliable extreme environmental loads than with conventional environmental contours. Therefore, the methodology presented in this study can be applied for constructing reasonable and reliable environmental contours, even when observation periods are limited.11Nsciescopu
Artificial light-enhanced cultivation of Arthrospira maxima for improved C-phycocyanin production in mid-latitude open raceway ponds
No full textLight is a crucial factor influencing microalgal growth. In open raceway pond (ORP) systems, seasonal light variations directly affect microalgal biomass production. In this study, annual cultivation of the cyanobacterium, Arthrospira maxima in ORPs located in South Korea, a mid-latitude region, showed a significant positive correlation between day length and biomass production (p < 0.05). Based on this, we proposed a hybrid strategy combining natural and artificial light to enhance C-phycocyanin (C-PC), a photosynthetic pigment from A. maxima. Laboratory-scale experiments investigated suitable light–dark cycle, effective wavelengths for growth and C-PC accumulation, and their mixing ratio. Continuous lighting (24 h light: 0 h dark, 24 L:0D) with red and blue light at an intensity ratio of 8:2 was identified as a highly effective condition for enhancing C-PC production. Under these conditions, biomass, intracellular C-PC, and C-PC yield per culture volume increased by 2.24-, 1.49-, and 3.32-fold, respectively, compared with 12 h light:12 h dark white light. These enhancing conditions were further applied in pilot-scale ORPs, where natural sunlight was used during the day and artificial light at night (on 1 h before sunset and off 1 h after sunrise). Seasonal C-PC production under this regime ranged from 114.16 ± 7.74–165.37 ± 1.03 mg L⁻¹, representing a 1.7- to 2.5-fold increase compared to sunlight-only cultivation. The extra costs of artificial light were offset by higher C-PC yield. In summary, this strategy provides a practical basis for enhancing C-PC production by A. maxima in mid-latitude ORP systems.11Nsciescopu
Exploring mitophagy levels in Drosophila Malpighian tubules unveils the pivotal role of mitophagy in kidney function and diabetic kidney disease
No full textMitophagy has been implicated in kidney function and related diseases. However, a direct analysis of mitophagy in kidney models, including disease models, remains notably lacking. Here we analyzed mitophagy levels in Drosophila Malpighian tubules, a functional analog of the human kidney, using a transgenic model of the engineered mitophagy reporter mt-Keima. We found that mitophagy is highly active in the major cell types of the Malpighian tubules, including renal stem cells, principal cells and stellate cells. Notably, the suppression of mitophagy by genetic downregulation of mitophagy-related genes, such as ATG5 and ULK1, led to a significant decrease in the secretion function of the Malpighian tubules, suggesting that mitophagy is essential for their proper function. Interestingly, a continuous high-sugar diet, which is used as a model for diabetic kidney disease, caused a reduction in mitophagy levels in principal cells before the development of mitochondrial dysfunction and defective secretion. Importantly, stimulation of mitophagy with the recently developed mitophagy inducer PDE701 rescued both mitochondrial dysfunction and defective phenotypes in a diabetic kidney disease model. Our results highlight the pivotal role of mitophagy in kidney function and suggest that modulating mitophagy could be a potential strategy for treating kidney diseases.11Ysciescopuskc
Behaviours of 210Pb and 137Cs in Yellow Sea sediments under the influence of waste dumping
No full textThis study presents and evaluates the distribution patterns and deposition fluxes of both natural and artificial radionuclides, 210Pb and 137Cs, in the sediments of the Yellow Sea region. Higher sediment deposition fluxes of 210Pb were observed in the muddy sediment area compared to the sandy area. In addition, the deposition fluxes of excess 210Pb at the dumping site and surrounding areas showed higher values (663.1 ± 588.6 Bq/m2 yr−1) than those at the non-dumping sites (359.7 ± 373.3 Bq/m2 yr−1) within the muddy area. Thus, although the sedimentation rates in the study area calculated using excess 210Pb showed an average value of 0.35 ± 0.23 cm yr−1, which is comparable with those reported in previous studies of the Yellow Sea, this study indicates the significant influence of anthropogenic waste dumping on the accumulation of 210Pb in the bottom sediments. The 137Cs activities in most stations exhibited an exponential decrease from the surface sediments, similar to the pattern of 210Pb, although one site showed peak values at depths of 9–13 cm. However, unlike the typical 137Cs peaks that correspond to major events, such as the 1963 nuclear tests, the age of the sediments at peak depths in this study ranged widely, from the 1950s to the 1970s. This imprecision in dating is likely attributable to the high sediment turbulence in the Yellow Sea and the weaker particle-reactive nature of 137Cs, which facilitates the remobilization of particulate 137Cs into the dissolved phase. Moreover, our results indicate a much lower deposition flux of 137Cs compared to previous studies, further demonstrating the limitations of using 137Cs as a tracer in high-sediment-surface areas. Overall, this study highlights the impact of waste dumping on the accumulation of 210Pb in marginal seas, even in dynamic sedimentary environments such as the Yellow Sea.11Nsciescopu
Miocene ice sheet dynamics and sediment deposition in the central Ross Sea, Antarctica
No full textDrill cores from the Antarctic continental shelf are essential for directly constraining changes in past Antarctic Ice Sheet extent. Here, we provide a sedimentary facies analysis of drill cores from International Ocean Discovery Program (IODP) Site U1521 in the Ross Sea, which reveals a unique, detailed snapshot of Antarctic Ice Sheet evolution between ca. 18 Ma and 13 Ma. We identify distinct depositional packages, each of which contains facies successions that are reflective of past baseline shifts in the presence or absence of marine-terminating ice sheets on the outermost Ross Sea continental shelf. The oldest depositional package (>18 Ma) contains massive diamictites stacked through aggradation and deposited in a deep, actively subsiding basin that restricted marine ice sheet expansion on the outer continental shelf. A slowdown in tectonic subsidence after 17.8 Ma led to the deposition of progradational massive diamictites with thin mudstone beds/laminae, as several large marine-based ice sheet advances expanded onto the mid- to outer continental shelf between 17.8 Ma and 17.4 Ma. Between 17.2 Ma and 15.95 Ma, packages of interbedded diamictite and diatom-rich mudstone were deposited during a phase of highly variable Antarctic Ice Sheet extent and volume. This included periods of Antarctic Ice Sheet advance near the outer shelf during the early Miocene Climate Optimum (MCO)—despite this being a well-known period of peak global warmth between ca. 17.0 Ma and 14.6 Ma. Conversely, there were periods of peak warmth within the MCO during which diatom-rich mudstones with little to no ice-rafted debris were deposited, which indicates that the Antarctic Ice Sheet was greatly reduced in extent and had retreated to a smaller terrestrial-terminating ice sheet, most notably between 16.3 Ma and 15.95 Ma. Post-14.2 Ma, diamictites and diatomites contain unambiguous evidence of subglacial shearing in the core and provide the first direct, well-dated evidence of highly erosive marine ice sheets on the outermost continental shelf during the onset of the Middle Miocene Climate Transition (MMCT; 14.2−13.6 Ma). Although global climate forcings and feedbacks influenced Antarctic Ice Sheet advances and retreats during the MCO and MMCT, we propose that this response was nonlinear and heavily influenced by regional feedbacks related to the shoaling of the continental shelf due to reduced subsidence, sediment infilling, and local sea-level changes that directly influenced oceanic influences on melting at the Antarctic Ice Sheet margin. Although intervals of diatom-rich muds and diatomite indicating open-marine interglacial conditions still occurred during (and following) the MMCT, repeated advances of marine-based ice sheets since that time have resulted in widespread erosion and overdeepening in the inner Ross Sea, which has greatly enhanced sensitivity to marine ice sheet instability since 14.2 Ma.11Nsciescopu
Mamba-based Fault Diagnosis of Underwater Thrusters
No full textAs the use of Unmanned Surface Vehicles (USVs) expands, fault diagnosis technology for underwater thrusters, which are key components, is becoming increasingly important. This study proposes a Mamba model-based fault diagnosis algorithm to diagnose faults in USV underwater thrusters. The proposed algorithm extracts features from vibration, current consumption, and control input data using a one-dimensional convolutional neural network (1D-CNN), and then designs a Mamba model to learn fault patterns and classify fault types. A normal condition and five fault scenarios caused by external factors during underwater thruster operation were simulated, including blade damage, floating debris entanglement, and biofouling. Sea trials were conducted to verify system performance. As a result, the proposed Mamba-based fault diagnosis algorithm achieved 98.05% accuracy in classifying six thruster conditions. The high accuracy verifies the applicability of the Mamba model to USV thruster fault diagnosis.2
Evaluation system for the marine heatwave simulation performance and method for the same
No full text본 발명은 기후모형의 해양열파 특성 오차 원인을 알아내기 위한 것으로, 모형이 모사하는 해면수온의 표
준편차(변동성)와 해면수온 선형경향성을 함께 이용하여 오차에 기여하는 두 요소의 비율과 크기를 연구자
에게 제시하는 평가시스템이다. 기여 정도는 -1부터 1까지의 범위를 갖으며, 0은 두 요소의 기여도가
50:50인 경우이다. 크기는 관측자료로 정규화(normalize)된 변동성과 선형경향성의 절대값의 합으로 나타
낸다
THERMALLY STABLE FGF7 POLYPEPTIDE AND USE OF THE SAME
No full textFGF7 활성을 가지며 온도안정성이 향상된 폴리펩타이드가 제공된다. 폴리펩타이드는 서열번호 1에서 120번
째 알라닌(A)이 시스테인(C)으로 치환되거나, 126번째 리신(K)이 글루탐산(E) 또는 아스파르트산(D)으로
치환되거나, 178번째 리신(K)이 글루탐산(E) 또는 아스파르트산(D)으로 치환되는 것 중에서 선택된 적어
도 하나 이상의 치환을 포함하고, FGF7 고유의 활성을 가지는 온도안정성을 향상시킨(thermally stable)
폴리펩타이드이
Consultation Mechanisms Between the Conference of the Parties of the BBNJ Agreement and Relevant Instruments, Frameworks and Bodies
No full textThe Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (the BBNJ Agreement) intends to centralise the establishment and management of area-based management tools (ABMT s). Meanwhile, an extensive network of existing instruments, frameworks, and bodies (IFB s) have been managing ABMT s with their legal mandates. During the negotiation of the BBNJ Agreement, it was controversial whether the Conference of the Parties (COP) of the BBNJ Agreement
or existing IFB s should be the main decision-makers in establishing and managing ABMT s. Despite the negotiators’ efforts, the BBNJ Agreement leaves the issue unresolved. This paper focuses on the two ambiguities related to the undecided balance between the COP and IFB s. First, the BBNJ Agreement is silent on what ‘relevant IFB s’ are in terms of the ABMT s. Second, the BBNJ Agreement is ambiguous about what the ‘mechanism’ for consultation is and what it should be under Article 22. In light of these two uncertainties, this paper explores the scope of relevant IFB s and examines the possible mechanisms of consultation between the COP and IFB s. This paper probes the ideal mechanism for the COP by exploring various inter-institutional
mechanisms adopted by IFB s, including both bilateral and multilateral mechanisms. This paper suggests the hub-and-spoke model as the ideal mechanism to streamline the issue of uncertainty in ‘relevant IFB s’ and to effectively implement Part III of the BBNJ Agreement.33Nscopu