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Soil depth- and root diameter- related variations affect root decomposition in temperate pine and oak forests

Journal of Plant Ecology 2019年第5期12卷 871-881页

作者： seung hyun han Seongjun Kim hanna Chang hyun-Jun Kim Asia Khamzina Yowhan Son Department of Environmental Science and Ecological Engineering Graduate SchoolKorea UniversityAnam-DongSeongbuk-GuSeoul 02841Republic of Korea

Aims Assessment of factors regulating root decomposition is needed to understand carbon and nutrient cycling in forest *** ob-jective of this study is to examine the effects of soil depth and root diameter on root decomposition and to analyze the relationship of root decomposition with factors such as soil environmental conditions and initial litter *** two decomposition experiments were conducted in natural pine(Pinus densiflora)and oak(Quercus serrata)forests over a 2-year period using the litterbag *** the soil depth experiment,216 litterbags containing fine roots(∅=0-2 mm)were buried at 0-10-,10-20-and 20-30-cm soil *** properties and soil enzyme activities and microbial biomass at each soil depth were *** the root diameter experiment,216 litterbags containing roots 0-1-,1-2-and 2-3-mm in diameter were buried at 10-cm soil *** initial litter qualities(carbon(c),nitrogen(N),calcium(ca)and phosphorus(P)concentrations)for each of the root diameter classes were *** were retrieved after 3,6,12 and 24 months in each forest *** Findingsthe root decomposition rate was significantly altered by soil depth and root *** 2 years,the root decay constant at 0-10-cm depth(pine:0.35 and oak:0.41)was significantly higher than that at 10-20-cm(0.31 and 0.37)and 20-30-cm(0.32 and 0.33)depths in the *** and *** *** activities and microbial biomass declined with soil depth,which may be associated with decreasing soil moisture and organic *** decay constant for the 0-1-mm roots(pine:0.32 and oak:0.37)was higher than that of 1-2-mm(0.29 and 0.33)and 2-3-mm roots(0.26 and 0.33)for the *** and *** *** in initial P concentration and c/N ratio among the different diameter roots were linearly related with root *** particular,the increasing c/N ratio with root diameter resulted in decreases in the decomposition *** re

关键词： decomposition stage litter quality soil environmental condition soil microbial activity

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Estimating the production and mortality of fine roots using minirhizotrons in a Pinus densiflora forest in Gwangneung,Korea

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Journal of Forestry Research 2016年第5期27卷 1029-1035页

作者： seung hyun han Soonjin Yun Jongyeol Lee Seongjun Kim hanna Chang Yowhan Son Department of Environmental Science and Ecological Engineering Graduate SchoolKorea University Department of Forest Conservation Korea Forest Research Institute Department of Biological and Environmental Sciences Qatar University

The aim of this study was to estimate fine root production （FP） and fine root mortality （FM） at 0-10, 10-20, and 20-30 cm soil depths using minirhizotrons in a 75-year-old Pinus densiflora Sieb. et Zucc. forest located in Gwangneung, Korea. We developed the conversion factors （frame cm-2） of three soil depths （0.158 for 0-10 cm, 0.120 for 10-20 cm, and 0.131 for 20-30 cm） based on soil coring and minirhizotron data. FP and FM were estimated using conversion factors from March 26, 2013 to March 2, 2014. The annual FP and FM values at the 0-30 cm soil depth were 3200.2 and 2271.5 kg ha-1 yr -1, respectively. The FP estimate accounted for approximately 17 % of the total net primary production at the study site. FP was highest in summer （July 31-September 26）, and FM was highest in autumn （September 27-November 29）. FP was positively correlated with seasonal change in soil temperature, while FM was not related to that change. The sea- sonality of FP and FM might be linked to above-ground photosynthetic activity. Both FP and FM at the 0-10 cm depth were significantly higher than at 10-20 and 20-30 cm depths, and this resulted from the decrease in nutrient availability with increasing soil depth. The minirhizotron approach and conversion factors developed in this study will enable fast and accurate estimation of the fine root dynamics in P. densiflora forest ecosystems.

关键词： Conversion factor Fine root Minirhizotron Mortality Production

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Antimicrobial effect of alexidine and chlorhexidine against Enterococcus faecalis infection

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International Journal of Oral Science 2013年第1期5卷 26-31页

作者： hyun-Shik Kim Seok Woo Chang seung-Ho Baek seung hyun han Yoon Lee Qiang Zhu Kee-Yeon Kum Department of Conservative Dentistry Dental Research Institute and BK21 ProgramSeoul National University Dental HospitalSeoul National University School of Dentistry Department of Conservative Dentistry School of DentistryKyung Hee University Department of Oral Microbiology and Immunology Dental Research Institute and BK21 ProgramSeoul National University Dental HospitalSeoul National University School of Dentistry Department of Dentistry Wonju College of Medicine Yonsei University Division of Endodontology School of Dental MedicineUniversity of Connecticut Health Center

A previous study demonstrated that alexidine has greater affinity for the major virulence factors of bacteria than *** aim of this study was to compare the antimicrobial activity of 1%alexidine with that of 2%chlorhexidine using Enterococcus faecalis-infected dentin *** bovine dentin blocks were prepared and randomly divided into six groups of 10 *** was inoculated on 60 dentin blocks using the Luppens apparatus for 24 h and then the dentin blocks were soaked in 2%chlorhexidine or 1%alexidine solutions for 5 and 10 min,*** saline was used as a *** antimicrobial efficacy was assessed by counting the number of bacteria adhering to the dentin surface and observing the degradation of bacterial shape or membrane rupture under a scanning electron *** fewer bacteria were observed in the 2%chlorhexidine-or 1%alexidine-soaked groups than in the control group(P0.05).Ruptured or antiseptic-attached bacteria were more frequently observed in the 10-min-soaked chlorhexidine and alexidine groups than in the 5-min-soaked chlorhexidine and alexidine *** conclusion,10-min soaking with 1%alexidine or 2%chlorhexidine can be effective against *** infection.

关键词： alexidine antibacterial effect chlorhexidine Enterococcus faecalis Luppens apparatus root canal soaking scanning electron microscope

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Soluble components of Hericium erinaceum induce NK cell activation via production of interleukin-12 in mice splenocytes

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Acta Pharmacologica Sinica 2007年第6期28卷 901-907页

作者： Myung-hyun YIM Jang-woo SHIN Jin-young SON Se-mi OH seung-hyun han Jung-hyo CHO Chong-kwan CHO Hwa-seung YOO Yeon-weol LEE Chang-gue SON East-West Cancer Center Dunsan Oriental Hospital of Daejeon UniversityDaejeon 302-122Korea

Aim:To investigate the immunoregulatory functions of water extracts of Hericiumerinaceum （WEHE） focusing on natural killer （NK） cell-based anticancer ***:Mouse splenocytes or purely isolated NK ceils were stimulated with1-100 mg/L WEHE for 24 h followed by co-culture with51Cr-labled Yac-1 cells for4 h,then NK cell-derived cytolytic activity was measured using a *** antibodies against mouse interleukin-12 （IL-12） were addedinto the WEHE-stimulated splenocytes,thereafter,cytotoxicity was measured toexamine the involvement of ***-PCR and ELISA analyses were performed toconfirm the induction of transcription and the translation of IL-12 and interferon-gamma （IFN-gamma） in the WEHE-treated ***:WEHE enhancedthe cytolytic activity of total splenocytes towards Yac-1 ceils in a ***,this activation was not observed when the NK cells isolatedfrom the splenocytes were treated with ***,the treatment withantibodies against IL-12 abolished the effect of WEHE on splenocyte-derivedcytolytic ***-PCR and ELISA analyses showed the induction of IL-12 andIFN-gamma in the WEHE-treated ***:WEHE indirectlyactivates the cytolytic ability of NK cells via the induction of IL-12 in totalsplenocytes,and possibly via other immuno-mediators or cellular components.

关键词： Hericium erinaceum NK cells interleukin-12

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An herbal formula,CGX,exerts hepatotherapeutic effects on dimethylnitrosamine-induced chronic liver injury model in rats

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World Journal of Gastroenterology 2006年第38期12卷 6142-6148页

作者： Jang-Woo Shin Jin-Young Son Se-Mi Oh seung-hyun han Jing-Hua Wang Jung-Hyo Cho Chong-Kwan Cho Hwa-seung Yoo Yeon-Weol Lee Myong-Min Lee Xiao Ping Hu Chang-Gue Son East-West Cancer Center Dunsan Oriental Hospitalof Orientai medical College of Daejeon University 1136 Dunsan-dong Seo-gu Daejeon 302-122 South Korea Department of Oromaxillofacial Infection and Immunity and Dental Research Institute School of Dentistry Seoul National University 28 Yongon-Dong Chongno-Gu Seoul 110-749 South Korea

AIM： To evaluate the therapeutic effect of Chunggan extract （CGX）, a modified traditional Chinese hepatotherapeutic herbal, on the dimethylnitrosamine （DMN）-induced chronic liver injury model in rats. METHODS： Liver injuries were induced in Wistar rats by injection of DMN （ip, 10 mg/mL per kg） for 3 consecutive days per week for 4 wk. The rats were administered with CGX Coo, 100 or 200 mg/kg per day） or distilled water as a control daily for 4 wk starting from the 15^th d of the DMN treatment. Biochemical parameters （serum albumin, bilirubin, ALP, AST and ALT）, lipid peroxides, hydroxyproline, as well as histological changes in liver tissues were analyzed. In addition, gene expression of TNF-α, TGF-β, TIMP-1, TIMP-2, PDGF-β, and MMP-2, all of which are known to be associated with liver fibrosis, were analyzed using real-time PCR. RESULTS： CGX administration restored the spleen weight to normal alter having been increased by DMN treatment. Biochemical analysis of the serum demonstrated that CGX significantly decreased the serum level of ALP （P 〈 0.05）, ALT （P 〈 0.02）, and AST （P 〈 0.02） that had been elevated by DMN treatment. CGX administration moderately lowered lipid peroxide production and markedly lowered hydroxyproline generation caused by DMN treatment in accordance with histopathological examination. DMN treatment induced a highly upregulated expression of TNF-α, TGF-β,TIMP-1, TIMP-2, PDGF-β, and MMP-2. Of these, the gene expression encoding PDGF-β and MMP-2 was still further enhanced 2 wk after secession of the 4-wk DMN treatment, and was remarkably ameliorated by CGX administration. CONCLUSION： CGX exhibits hepatotherapeutic properties against chronic hepatocellular destruction and consequential liver fibrosis.

关键词： Dimethylnitrosamine Hepatotherapeutic Herbal medicine PDGF-β Chunggan extract

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Toxicological study of the hepatotherapeutic herbal formula,Chunggan extract,in beagle dogs

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World Journal of Gastroenterology 2006年第46期12卷 7497-7502页

作者： Woo-Jin Choi Jang-Woo Shin Jin-Young Son Dong-Seok Seo Hark-Soo Park seung-hyun han Ha-lung Sung Jung-Hyo Cho Chong-Kwan Cho Hwa-seung Yoo Yeon-Weol Lee Chang-Gue Son East-West Cancer Center Dunsan Oriental Hospital of Oriental medical Collage of Daejeon University 1136Dunsan-dong Seo-gu Daejeon 302-122 South Korea Safety Assess-ment Center Korea Testing and Research Institute for Chemical Industry 7-6 Gomak-ri Wolgot-myeon Gimpo-si Kyonggi-doKorea Department of Oromaxillofacial Infection & Immunity and Dental Research Institute School of DentistrySeoul National University 28 Yongon-Dong Chongno-Gu Seoul110-749 South Korea

AIM: To evaluate the pharmaceutical safety of a Chinese herbal formula, Chunggan extract (CGX), traditionally prescribed as a hepatotherapeutic drug via systemic acute and subacute toxicological study. METHODS: Twenty male dogs and 20 female dogs were fed doses 50 times and 4 times greater than the clinically-recommended drug dosages in an acute and a subacute toxicological study, respectively. Adverse effects were examined by comparing the differences between normal and drug-administered groups using clinical signs, necropsies, histopathologic findings, haematology, urinalysis, and biochemical analysis. RESULTS: In the acute study no change in the body weight, diarrhoea, apetite, mortality rate and histopa- thology of major organs was observed in male or female dogs with a single administration of CGX at 5 g/kg. No drug-induced abnormalities at analysis of histopathology, haematology, urinalysis, and biochemistry were found with any dose of this drug. CONCLUSION: CGX is supposed to be very safe when used in a clinical application with a wide therapeutic index.

关键词： Hepatotherapeutics Herbal remedy Chung-gan extract Safety Toxicological study

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Bacterial entombment by intratubular mineralization following orthograde mineral trioxide aggregate obturation: a scanning electron microscopy study

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International Journal of Oral Science 2014年第4期6卷 227-232页

作者： Jun Sang Yoo Seok-Woo Chang So Ram Oh Hiran Perinpanayagam Sang-Min Lim Yeon-Jee Yoo Yeo-Rok Oh Sang-Bin Woo seung-hyun han Qiang Zhu Kee-Yeon Kum Department of Dentistry U Dental Hospital Department of Conservative Dentistry School of Dentistry Kyung Hee University Department of Conservative Dentistry Dental Research Institute Seoul National University Dental Hospital Seoul National University School of Dentistry Division of Restorative Dentistry Schulich School of Medicine & Dentistry University of Western Ontario Department of Conservative Dentistry Jukjeon Dental Hospital College of Dentistry Dankook University Department of Oral Microbiology & Immunology Dental Research Institute and BK21 Program Seoul National University School of Dentistry Division of Endodontology Department of Oral Health and Diagnostic Sciences School of Dental Medicine University of Connecticut Health Center

The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate（MTA） was studied by scanning electron microscopy（SEM）. Single-rooted human premolars（n560） were instrumented to an apical size #50/0.06 using ProF ile and treated as follows： Group 1（n510） was filled with phosphate buffered saline（PBS）; Group 2（n510） was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3（n520） was obturated orthograde with a paste of OrthoM TA（BioM TA, Seoul, Korea） and PBS; and Group 4（n520） was incubated with E. faecalis for 3 weeks and then obturated with OrthoM TA–PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material（IRM）, and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoM TA-filled roots（Groups 3 and 4）. Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots（Group 4）. Therefore, the orthograde obturation of root canals with OrthoM TA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.

关键词： bacterial entombment intratubular mineralization orthograde canal obturation scanning electron microscopy tag-like structure

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Effect of smoking on the risk of gastrointestinal cancer after cholecystectomy: A national population-based cohort study

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World Journal of Gastrointestinal Surgery 2024年第9期16卷 2796-2807页

作者： Minseob Kim Kyung-Do han seung-hyun Ko Yoonkyung Woo Jae hyun han Department of Surgery Graduate School of MedicineThe Catholic University of KoreaSeoul 06591South Korea Department of Statistics and Actuarial Science Soongsil UniversitySeoul 06978South Korea Division of Endocrinology and Metabolism Department of Internal MedicineSt Vincent’s HospitalCollege of MedicineThe Catholic University of KoreaSuwon 16247South Korea Division of Hepatobiliary-Pancreas Surgery and Liver Transplantation Department of SurgerySt Vincent’s HospitalCollege of MedicineThe Catholic University of KoreaSuwon 16247South Korea

BACKGROUND The role of smoking in the incidence of colorectal cancer(CRC)or gastric cancer(GC)in populations undergoing cholecystectomy has not been *** To evaluate the effect of smoking on CRC or GC development in cholecystectomy *** A total of 174874 patients who underwent cholecystectomy between January 1,2010 and December 31,2017 were identified using the Korean National Health Insurance Service claims *** patients were matched 1:1 with mem-bers of a healthy population according to age and *** or GC risk after cholecystectomy and the association between smoking and CRC or GC risk in cholecystectomy patients were evaluated using adjusted hazard ratios(HRs)and 95%*** The risks of CRC(adjusted HR:1.15;95%CI:1.06-1.25;P=0.0013)and GC(adjusted HR:1.11;95%CI:1.01-1.22;P=0.0027)were significantly higher in cholecystectomy *** the population who underwent cholecystectomy,both CRC and GC risk were higher in those who had smoked compared to those who had never *** both cancers,the risk tended to increase in the order of non-smokers,ex-smokers,and current *** addition,a positive correlation was observed between the amount of smoking and the risks of both CRC and *** Careful follow-up and screening should be performed,focusing on the increased risk of gastrointestinal cancer in the cholecystectomy group,particularly considering the individual smoking habits.

关键词： Cholecystectomy Smoking,Gastric cancer Colon cancer Risk factor Hazard ratio

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Flow Characteristics in Compact Thermal Spray Coating Systems with Minimum Length Nozzle

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Plasma Science and Technology 2009年第5期11卷 550-554页

作者： seung-hyun KIM Youn-Jea KIM School of Mechanical Engineering Sungkyunkwan University

In this study, numerical analysis is performed to adopt the equivalence ratio on the high velocity oxygen fuel （HVOF） thermal spray coating systems equipped with a minimum length nozzle. The analysis is applied to investigate the axisymmetric, steady-state, turbulent, and chemically combusting flow both within the torch and in a free jet region between the torch and the substrate to be coated. The combustion is modeled using a single-step and eddy-dissipation model which assumes that the reaction rate is limited by the turbulent mixing rate of the fuel and oxidant. As the diameter of the nozzle throat is increased, the location of the Mach shock disc moves backward from the nozzle exit. As the throat diameter and the divergent portion are 6 mm and 8 mm, respectively, the pressure in the HVOF system is the lowest at the chamber and the expanding gas is steadily maintained with both high velocity and high temperature for different equivalence ratios. Thus, relatively minor amendments of the equivalence ratio and the geometry of HVOF can lead to improved control over coating characteristics.

关键词： minimum length nozzle HVOF equivalence ratio

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Adverse effects of early-life stress:focus on the rodent neuroendocrine system

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Neural Regeneration Research 2024年第2期19卷 336-341页

作者： seung hyun Lee Eui-Man Jung Department of Molecular Biology College of Natural SciencesPusan National UniversityBusanRepublic of Korea

Early-life stress is associated with a high prevalence of mental illnesses such as post-traumatic stress disorders,attention-deficit/hyperactivity disorder,schizophrenia,and anxiety or depressive behavior,which constitute major public health *** the early stages of brain development after birth,events such as synaptogenesis,neuron maturation,and glial differentiation occur in a highly orchestrated manner,and external stress can cause adverse long-term effects throughout *** body utilizes multifaceted mechanisms,including neuroendocrine and neurotransmitter signaling pathways,to appropriately process external *** individuals first exposed to early-life stress deploy neurogenesis as a stress-defense mechanism;however,in adulthood,early-life stress induces apoptosis of mature neurons,activation of immune responses,and reduction of neurotrophic factors,leading to anxiety,depression,and cognitive and memory *** process involves the hypothalamus-pituitary-adrenal axis and neurotransmitters secreted by the central nervous system,including norepinephrine,dopamine,and *** rodent early-life stress model is generally used to experimentally assess the effects of stress during *** paper reviews the use of the early-life stress model and stress response mechanisms of the body and discusses the experimental results regarding how early-life stress mediates stress-related pathways at a high vulnerability of psychiatric disorder in adulthood.

关键词： early-life stress hypothalamic-pituitary-adrenergic axis maternal separation mental illness neurodevelopmental disorder neuroendocrine system neurotransmitter

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