• Korean Journal of Remote Sensing
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• v.33 no.5_2
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• pp.709-720
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• 2017

In this study, we tried to analyze the correlation between corn yield and, satellite-based vegetation index, NDVI (Normalized Difference Vegetation Index) and various climatic factors in the three provinces of Northeast China during the past 20 years (1996-2015). The corn yields in the corn cultivation area of all three provinces showed a statistically significant positive correlation with the NDVI of the harvest period. Also, these have significant negative correlation with the daily maximum temperature in August and September and the occurrence frequency of above $30^{\circ}C$ for the summer season. The correlation between the corn yields and the precipitation showed a significant positive coefficient in only Liaoning Province in July, but the correlation was not found in Jilin and Heilongjiang Provinces. In this study, the NDVI and the daily maximum temperature data are suitable to be used as predictors of corn yield in the three provinces of Northeast China provinces.

• Journal of Ginseng Research
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• v.40 no.3
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• pp.220-228
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• 2016

Background: Among the various ginseng strains, Shizhu ginseng is endemic to China, mainly distributed in Kuandian Manchu Autonomous County (Liaoning Province, China); however, not much is known about the compounds (especially saponins) in Shizhu ginseng. Methods: A rapid, sensitive, and reliable ultra-high performance liquid chromatography coupled with MS/MS (UHPLC-MS/MS) method was developed to separate and identify saponins in Shizhu ginseng. Results: The separation was carried out on a Waters ACQUITY UPLC BEH $C_{18}$ column ($100mm{\times}2.1mm$, $1.7{\mu}m$) with acetonitrile and 0.1% formic acid aqueous solution as the mobile phase under a gradient elution at $40^{\circ}C$. The detection was performed on a Micromass Quattro Micro API mass spectrometer equipped with electrospray ionization source in both positive and negative modes. Under the optimized conditions, a total of 31 saponins were identified or tentatively characterized by comparing retention time and MS data with related literatures and reference substances. Conclusion: The developed UHPLC-MS/MS method was suitable for identifying and characterizing the chemical constituents in Shizhu ginseng, which provided a helpful chemical basis for further research on Shizhu ginseng.

• Journal of Ginseng Research
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• v.44 no.2
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• pp.205-214
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• 2020

Background: This article aims to compare and analyze the contents of ginsenosides in ginseng of different plant ages from different localities in China. Methods: In this study, 77 fresh ginseng samples aged 2-4 years were collected from 13 different cultivation regions in China. The content of eight ginsenosides (Rg₃, Rc, Rg₁, Rf, Rb₂, Rb₁, Re, and Rd) was determined using rapid resolution liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (RRLC-Q-TOF MS/MS) to comparatively evaluate the influences of cultivation region and age. Results: Ginsenoside contents differed significantly depending on age and cultivation region. The contents of ginsenosides Re, Rc, Rg₁, Rg₃, and Rf increased with cultivation age, whereas that of ginsenoside Rb₁ peaked in the third year of cultivation. Moreover, the highest ginsenoside content was obtained from Changbai (19.36 mg/g) whereas the lowest content was obtained from Jidong (12.05 mg/g). Ginseng from Jilin Province contained greater total ginsenosides and was richer in ginsenoside Re than ginseng of the same age group in Heilongjiang and Liaoning provinces, where Rb₁ and Rg₁ contents were relatively high. Conclusion: In this study, RRLC-Q-TOF MS/MS was used to analyze ginsenoside contents in 77 ginseng samples aged 2-4 years from different cultivation regions. These patterns of variation in ginsenoside content, which depend on harvesting location and age, could be useful for interested parties to choose ginseng products according to their needs.

• Journal of the Economic Geographical Society of Korea
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• v.20 no.3
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• pp.329-352
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• 2017

Since the late 2000s Korean foreign direct investors in North Korea and China border regions have gone through the closure of outward processing trade(OPT) networks and changes in their location due to UN security council resolution and Korean independent sanctions against North Korea's nuclear and missile tests. However, the introduction of new Chinese OPT policy has led to the invigoration of domestic market-based OPT networks towards North Korea. The main aim of this paper is to identify the exceptional characteristics of Dandong in Liaoning province, a North Korea and China border region by analyzing OPT networks towards North Korea. Fundamentally the establishment of OPT networks towards North Korea is likely to be based on the utilization of a plenty of low wages in North Korea. The main reasons for this are fallen into two perspectives: geo-economics and geo-politics. The first perspective is geo-economics centering on the consolidation of economic exchange between North Korea and China, and North Korean economic development. For example, the introduction of Chinese OPT in border region has enabled Chinese local firms based on domestic market to access a plenty of low wage in North Korea in formal and institutional contexts. The second is geo-politics for the stability of North Korean regime based on the means of geo-economics. As the invigoration of domestic market-based OPT networks might make North Korea possible promoting foreign money earning, it enable North Korea to be sustainable as a buffering region between capitalist and socialist regime for China. It shows Chinese geo-strategic attempts to deal with the economic and regime stability of North Korean as a buffering state. In other words, OPT networks in North Korea should be concerned with the discourse practice of geo-economics and geo-politics which might lead to various and contingent spatial economies in border region. As a consequence, North Korea and China border regions could defined as a space in which is applicable to exceptional institutions and policies, and an exploitative space in which create surplus and rents by utilizing a plenty of low wages in North Korea through OPT networks.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.167-174
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• 2012

Transport of marine debris between countries is a potential source of diplomatic conflicts. U-i Island in Shinan County, Jeonnam Province has been reported by media as being damaged by marine debris from foreign countries. However, scientific researches on those marine debris have not been published. So, the features of foreign marine debris on Seongchon Beach in U-i Island were surveyed on Feb. 2012. The ratio of marine debris from foreign countries was 34.7% by number of items, 56.3% by weight, and 48.5% by volume in $200m^2$ transacts. Most of them, 98.9% in number, were inferred to be originated from China. The most abundant items were plastic beverage bottles and black floats. The total number of black floats was 539 within the 1,100m beach. Fifteen of them had information on manufactured locations, of which 87.6% were Liaoning Province in northern China. As domestic policy cannot prevent the inflow of the marine debris from foreign countries, countermeasures should be sought out from the international cooperation with the neighboring countries. For the black floats, recycling method should be developed as lots of the same types of black floats are drifted ashore in winter. And, as the U-i Island is a National Park with its valuable natural heritages, methods should be designed to minimize impacts on dune topography and ecology.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.371-376
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• 2017

In a nationwide survey of the occurrence and density of the migratory locust (Locusta migratoria), high density was continuously observed in the reclaimed areas of Mangun-myeon in Muan-gun, Jeollanam-do, and Sanye-myeon in Haenam-gun, Jeollanam-do, Korea. We have analyzed the nucleotide sequences of NADH dehydrogenase subunit (NAD) 2, NAD4, and NAD5 genes in order to determine the origins of the migratory locusts at two sites. According to the analysis, the migratory locusts in Haenam-gun were closely related with those in Liaoning Province and Heilongjiang Province in the northeast China. In contrast, the migratory locusts in Muan-gun were most similar to those in Japan. Because Korean migratory locusts were not included in the previous global study on the evolution and migration of migratory locusts, we did not know the origin of Korean migratory locusts, earlier. Phylogenetic analyses this study suggested that the migratory locusts from the northeast Chinese population might have migrated and settled in Haenam-gun in Korea. Moreover, another northeast Chinese population might have migrated to Muan-gun in Korea though Sakhalin, Russia and Hokkaido, Japan. However, the possibility that the migratory locusts moved from northeast China might be isolated from each other in Korea, and that the Muan population might migrate to Japan cannot be excluded.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.175-184
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• 2016

In this study, we transplanted Chinese (Liaoning Dandong) and Chungnam (Taean) manila clam seeds to Gochang tidal flats in Jeonbuk province, and compared growth, mortality, and condition indices from May 2015 to August 2016. Within 2 months after transplantation, clam mortality of Chungnam and Chinese origin were $6.9{\pm}4.3%$, $16.9{\pm}7.9{\sim}21.0{\pm}6.3%$, respectively. We supposed that higher mortality of Chinese manila clams might be due to higher stress and weakening of physiological functions by air-exposure and unavailability of food intake for 5 days harvesting, transportation, quarantine procedures. Unlike the local clam farmer's opinion based on their field experience, growth of Chungnam clams in shell length and total weight were a little better than Chinese without statistical significant difference (P > 0.05). Condition indices of Chinese clams showed declining tendency after reaching a peak in May 2014, and in June 2015, respectively. Meanwhile, Chungnam clams has reached its peak of condition indices in May 2014 and in April 2015, respectively. From this result, we supposed that there might be at least one month difference in reproduction between the Chinese and Chungnam manila clams during the first-transplanted year. Because the mortality of adult clam have sharply increased from June 2015 (due to high temperature, few rainfall and spawning) in Gochang tidal flat, it would be recommendable that farmers harvest the clams before June when its shell length are larger than 40 mm. In conclusion, we could directly compare the productivity of Chinese and Chungnam manila clam at Gochang tidal flats by field experiment, and these results are also meaningful to manila clam farmers.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.10021-10025
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• 2014

Background: The study aimed to describe the age distribution of breast cancer diagnosis among Chinese females for comparison with the United States and the European Union, and provide evidence for the screening target population in China. Materials and Methods: Median age was estimated from hospital databases from 7 tertiary hospitals in China. Population-based data in China, United States and European Union was extracted from the National Central Cancer Registry, SEER program and GLOBOCAN 2008, respectively. Age-standardized distribution of breast cancer at diagnosis in the 3 areas was estimated based on the World Standard Population 2000. Results: The median age of breast cancer at diagnosis was around 50 in China, nearly 10 years earlier than United States and European Union. The diagnosis age in China did not vary between subgroups of calendar year, region and pathological characteristics. With adjustment for population structure, median age of breast cancer at diagnosis was 50~54 in China, but 55~59 in United States and European Union. Conclusions: The median diagnosis age of female breast cancer is much earlier in China than in the United States and the European Union pointing to racial differences in genetics and lifestyle. Screening programs should start at an earlier age for Chinese women and age disparities between Chinese and Western women warrant further studies.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.347-350
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• 2013

The aim of the present study was to determine whether allogeneic red blood cell transfusions showed a deleterious effect and what might be preoperative risk factors for blood transfusion in patients with TNM stage II colon cancer. Total 470 patients who fulfilled inclusion criteria were selected for a further 10-year follow-up study. We found that there were statistical significance between non-transfused and transfused group in mortality (P=0.018), local recurrence (P=0.000) and distant metastasis (P=0.040). Local recurrence and distant metastasis between 1 to 3 units and more than 3 units group did not show any significant differences. There was no difference in survival rate between non-transfused and 1 to 3 units group (log rank=0.031, P=0.860). The difference between different blood transfusion volume in transfused patients was found (78.77% vs 63.83%, P=0.006). Meanwhile, the significant difference of survival rate was existed between non-transfused group and more than 3 units group (84.83% vs 63.83%, P=0.002 ). Univariate analysis showed the following 3 variables to be associated with an increased risk of allogeneic blood transfusions: preoperative CEA level (P<0.05), location of tumor (P<0.01) and diameter of tumor (P<0.01). Multivariate analysis revealed that location of tumor and diameter of tumor are two independent factors for requirement of perioperative transfusions. Therefore, allogeneic transfusion increase the postoperative tumor mortality, local recurrence and distant metastasis in patients with stage II colon cancer. The postoperative tumor mortality, local recurrence and distant metastasis were not associated with the blood transfusion volume. The blood transfusion volume was associated with the survival rate. Location of tumor and diameter of tumor were the independent preoperative risk factors for blood transfusion.

• Korean journal of applied entomology
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• v.61 no.2
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• pp.335-347
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• 2022

We investigated the emergence patterns of Chilo suppressalis (Lepidoptera: Crambidae) adults using sex pheromone traps in the three northeastern areas, Dandong (40°07'N 124°23'E) (Liaoning province), and Gongzhuling (43°30'N 124°49') and Longjing (42°46'N 129°26'E) (Jilin province), China, in 2020 and 2021. Two times of adult flight seasons were isolated clearly during the rice growing periods in the all areas, in which the first season from mid May to late July, and the second season from mid July to mid September were observed. The adult emergence seasons in the areas at higher latitude were later than that at lower latitude. Using the adult emergence data during the first flight seasons, the second flight seasons were estimated through insect phenology modelling, and compared with the observed data. Temperature-dependent life history models (developmental rate, development completion, survival rate, adult aging rate, total fecundity, oviposition completion, and adult survival completion) were collected or constructed for each life stage of C. suppressalis, in which the data from the four previous studies were used. Those models were combined in an insect phenology estimation software, PopModel, and operated for the observed areas. In the results, the phenology modelling operated with the models based on the data of shorter larval periods in the previous studies estimated more accurately the second flight seasons. In 2021, we investigated the change of damaged hill ratios of rice with observing the adult emergence at Dandong and Longjing, 2021. The increase periods of damaged hill ratios of rice were observed two times during the total rice cultivation season, which may be caused by different generations of C. suppressalis larvae.