• Ocean and Polar Research
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• 제30권1호
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• pp.21-31
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• 2008

Analyzing the results of East Sea Regional Ocean Model using a 3-dimensional variational data assimilation scheme, we investigated spatial and temporal variability of the North Korean Cold Current (NKCC) in the East Sea. The climatological monthly mean transport of the NKCC clearly shows seasonal variation of the NKCC within the range of about 0.35 Sv ($=0^6m^3/s$), which increases from its minimum (about 0.45 Sv) through December-January to March, decreases during March and May, and then increases again to the maximum (about 0.8 Sv) in August-September. The volume transport of the NKCC shows interannual variation of the NKCC with the range of about 1.0 Sv that is larger than seasonal variation. The southward current of the NKCC appears often not only in summer but in winter as well. The width of the NKCC is about 35 km near the Korean coast and its core is located under the East Korea Warm Current. The North Korean Cold Water (NKCW), characterized by low salinity and low temperature, is located both under the Tsushima Warm Water and in the western side of the maximum southward current of the NKCC that means the NKCC advects the NKCW southward along the Korean coast. It is revealed that the intermediate low salinity water, formed off the Vladivostok in winter, flows southward to the south of $37^{\circ}N$ through $2{\sim}3$ paths; one path along the Korean coast, another one along $132^{\circ}E$, and the middle path along $130^{\circ}E$. The path of the intermediate low salinity varies with years. The reanalysis fields suggest that the NKCW is advected through the paths along the Korean coast and along $130^{\circ}E$.

• Fisheries and Aquatic Sciences
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• 제18권2호
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• pp.173-181
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• 2015

We identified the $Na^+-K^+-2Cl^-$ cotransporter 2 (NKCC2) cDNA isoform from starry flounder, Platichthys stellate. The NKCC2 cDNA encoded a polypeptide of 1,043 amino acids representing 12 putative transmembrane domains based on the bioinformatic topology prediction. In addition, starry flounder NKCC2 possessed highly conserved residues within transmembrane domain 4, known as an essential site for its function. End-point reverse transcription-polymerase chain reaction analysis revealed that the NKCC2 transcript was moderately expressed only in the anterior and posterior intestines and the rectum. The NKCC2 mRNA level in the rectum, but not in other segments, was significantly induced 3 days post Streptococcus parauberis challenge, indicating that excess salt may be transported into the rectum. Taken together, our data indicate that an S. parauberis infection could tip the intestinal fluid balance in favor of fluid accumulation, indicating that bacterial pathogens can interfere with intestinal osmotic balance and normal mucosal immune homeostasis.

• The Korean Journal of Physiology and Pharmacology
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• 제19권3호
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• pp.249-255
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• 2015

Wnk kinase maintains cell volume, regulating various transporters such as sodium-chloride cotransporter, potassium-chloride cotransporter, and sodium-potassium-chloride cotransporter 1 (NKCC1) through the phosphorylation of oxidative stress responsive kinase 1 (OSR1) and STE20/SPS1-related proline/alanine-rich kinase (SPAK). However, the activating mechanism of Wnk kinase in specific tissues and specific conditions is broadly unclear. In the present study, we used a human salivary gland (HSG) cell line as a model and showed that $Ca^{2+}$ may have a role in regulating Wnk kinase in the HSG cell line. Through this study, we found that the HSG cell line expressed molecules participating in the WNK-OSR1-NKCC pathway, such as Wnk1, Wnk4, OSR1, SPAK, and NKCC1. The HSG cell line showed an intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) increase in response to hypotonic stimulation, and the response was synchronized with the phosphorylation of OSR1. Interestingly, when we inhibited the hypotonically induced $[Ca^{2+}]_i$ increase with nonspecific $Ca^{2+}$ channel blockers such as 2-aminoethoxydiphenyl borate, gadolinium, and lanthanum, the phosphorylated OSR1 level was also diminished. Moreover, a cyclopiazonic acid-induced passive $[Ca^{2+}]_i$ elevation was evoked by the phosphorylation of OSR1, and the amount of phosphorylated OSR1 decreased when the cells were treated with BAPTA, a $Ca^{2+}$ chelator. Finally, through that process, NKCC1 activity also decreased to maintain the cell volume in the HSG cell line. These results indicate that $Ca^{2+}$ may regulate the WNK-OSR1 pathway and NKCC1 activity in the HSG cell line. This is the first demonstration that indicates upstream $Ca^{2+}$ regulation of the WNK-OSR1 pathway in intact cells.

• Biomolecules & Therapeutics
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• 제3권4호
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• pp.273-278
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• 1995

The effect of methamphetamine on the pulmonary metastasis was investigated in C57BL/6 mice injected with Bl6 melanoma cells. Bl6 melanoma cells (2$\times$10$^{5}$ cells) were injected intravenously into 5~7 weeks old C57BL/6 mice. Mice were then treated intraperitoneally with methamphetamine either acutely (two times with one week interval) or subchronically (daily for 14 days). Degree of pulmonary metastasis was investigated and specific immunologic parameters such as natural killer cell cytotoxicity(NKCC), antibody-dependent cellular cytotoxicity(ADCC) and blastogenic responses of splenocytes were examined. Mice which had been subchronically treated with methamphetamine showed significant decreases in the number of pulmonary metastasis of Bl6 melanoma cells, NKCC and ADCC without a significant change in blastogenic responses. In the acutely-treated group, slight trends of decrease in the numbers of pulmonary metastasis, NKCC and ADCC were observed without statistical significances whereas there was a significant increase in blastogenic responses. The mechanism underlying the decrease in the degree of metastasis despite diminished NKCC and ADCC after methamphetamine treatment and the relationship between the degree of pulmonary metastasis and duration of methamphetamine treatment remain to be investigated.

• 한국해양학회지
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• 제16권1호
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• pp.1-11
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• 1981

The seasonal variations of surface current patterns in the Japan Sea were drawn out from the results of drift bottle experiments, current measurements and hydrographic observations during 1979∼1980. The North Korean Cold Current(NKCC) and the East Korean Warm Current(EKWC) were common features of circulation in the eastern sea of Korea. The intrusion of NKCC along the Korean coast became strong in summer(average velocity of 47.4cm/sec off Jumunjin and 23.4cm/sec near Jugbyeon) when the Tsushima Current was strong. But there was no indication of the NKCC in November 1979. Dynamic topography(August & November 1979) and satellite picture(November 1979) seemed to show the topographic steering of EKWC beginning off Janggigab. Drift bottles arrived at the Japaness coast were affected significantly by the strong Tsushima Current in summer and by the predominant northwesterlies in winter instead of weak current.

• 한국지구과학회지
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• 제41권5호
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• pp.490-503
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• 2020

해류와 해양 순환은 지구의 에너지를 분배하는 조절자로서 중요한 역할을 하고 있다. 2015 개정 교육과정에 기반한 중등학교 과학 및 지구과학 교과서에는 한반도 주변 해류 중 북한한류의 계절변동성에 대한 오개념을 포함하고 있는 것으로 드러났다. 이를 분석하기 위하여 중학교 5종, 고등학교 6종 교과서에 제시되어 있는 북한한류와 관련된 교과내용을 수집하였으며, 중등학교 과학교사 30인을 대상으로 해류와 북한한류에 관한 설문 조사를 실시하였다. 설문 내용은 교과서에서 북한한류에 대해서 언급하고 있는지, 북한한류의 시간변동성에 대한 개념의 오류가 있는지에 관한 질문으로 구성하였고, 북한한류와 관련된 자유로운 의견을 수집하였다. 교과서에서는 북한한류의 유속이 겨울에 강하다고 제시되어 있는데, 이는 그동안 장기간의 과학계의 연구 결과와는 정반대로 배치되는 결과이다. 북한한류의 세기는 여름에 강함에도 불구하고 겨울에 강하다고 교과서에서 제시하고 있는 것에 대한 오개념의 원인과 형성 과정을 조사하였다. 교사대상 설문을 분석한 결과, 대부분의 교사들이 북한한류의 세기가 겨울에 강하다는 지식 오류를 가지고 있었다. 이는 교사들이 가지고 있는 용어에 대한 오개념에서 출발하여 교사들의 확고한 지식으로 각인되어 있었다. 이러한 오개념은 교사 자신이 중등학교 재학시절부터 획득한 지식에서 기원하였고, 교과서의 오개념은 수정되지 않은 상태로 오랫동안 교사와 학생들에게 전달되고 있었다. 이러한 상황은 향후 학생들의 오개념을 재생산하는 구조를 가질 수 있을 것으로 예상된다. 따라서 본 연구는 교사 및 학생들이 가지고 있는 북한한류의 계절변동성에 관한 오개념을 단절하기 위하여 기존의 과학적 연구 결과들의 요약하였고, 교과서 수정의 필요성과 교사 전문성 신장을 위한 재교육의 필요성을 제안하였다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 춘계학술대회
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• pp.95-112
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• 2003

• Ocean and Polar Research
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• 제36권2호
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• pp.165-177
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• 2014

In an effort to investigate the structure and variability of the coastal current in the East Sea, a moored ADCP observation was conducted off Uljin from late May to mid-October 2006. Owing to the transition of season from summer to autumn, the features of the current and wind can be divided into two parts. Until mid-August (Part-I), a southward flow is dominant at all depths with a mean alongshore velocity of 4.2~8.9 cm/s but northward winds are not strong enough to reverse the near-surface current. During Part-II, a strong northward current occurs frequently in the upper layer but winds are predominantly southward including two typhoons that have deep-reaching influence. Profile of mean velocity has three layers with a northward velocity embedded at 12~28 m depth. The near-surface current of Part-II significantly coheres with winds at 4-8 day periods with a phase lag of about 12 hours. The modal structure of the current obtained by EOF analysis is: (1) Mode-1, having 83.6% of total variance, represents the current in the same direction at all depths corresponding to the southward North Korean Cold Current (NKCC). (2) Mode-2 (11.7%) reveals a two-layer structure that can be explained by the northward East Korean Warm Current (EKWC) in the upper layer and NKCC in the lower. (3) Mode-3 (2.6%) has three layers, in which the EKWC is reversed near the surface by opposing winds. This mode is particularly similar to the mean velocity profile of Part-II.

• Ocean and Polar Research
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• 제25권3호
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• pp.287-302
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• 2003

The seasonal variations in the circulation of the water mass in the East Sea/Japan Sea have been simulated using a free surface primitive ocean model, RIAMOM (RIAM Ocean Model), comparing the results from GFDL-MOM1 (Geophysical Fluid Dynamics Laboratory Modular Ocean Model, version 1.1, hereafter MOM) with the GDEM (Generalized Digital Environmental Model) data. Both models appear to successfully reproduce the distinct features of circulation in the East Sea/Japan Sea, such as the NB (Nearshore Branch) flowing along the Japanese coast, the EKWC (East Korean Warm Current) flowing northward along the Korean coast, and the NKCC/LCC (North Korean Cold Current/Liman Cold Current) flowing southwestward along Korean/Russian coast. RIAMOM has shown better performance, compared to MOM, in terms of the realistic simulation of the flow field in the East Sea/Japan Sea; RIAMOM has produced more rectified flows on the coastal region, for example, the narrower and stronger NKCC/LCC than MOM has. There is however obvious differences between the model results and the GDEM data in terms of the calculation of the water mass; both models have shown a tendency to overpredict temperature and underpredict salinity below 50m; more diffusive forms of thermocline and halocline have been simulated than noted in GDEM data.

• 한국해안해양공학회지
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• 제8권2호
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• pp.215-220
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• 1996

동한만을 중심으로 한 동해 북서해역의 계절별 및 연별 표층해황 특성을 고찰하였다. 동한만의 계절별 해황은 춘계에 동한난류수의 세력이 우세하다가 하리에 북한한류의 강화와 더불어 냉수역이 발달하는 형과, 봄부터 냉수의 세력이 탁월하다가 여름이 되면서 동한난류수의 영향을 받는 형의 두가지 유형을 보인다. 경년변동 특성도 동한난류와 북한한류간의 흐름의 상대적 세기와 유로에 따라 4가지 유형으로 분류된다. 각각의 경우, 동한만 부근에는 대ㆍ소규모의 저기압성 냉수과 혹은 고기압성 난수과가 발달하는 것이 한 특징이다.