On Surface O3 Associated with Long-Range Transport in the Yellow Sea Region     

H. S. Kim  Y. S. Chung 《Water, air, and soil pollution》2005,165(1-4):95-112

Measurements of surface ozone (O₃) and nitrogen oxides (NO _x ) were conducted at Tae-ahn (TAP) and Chongwon (CHN) on the Korean Peninsula, during the Aerosol Characterization Experiment—Asian Pacific region (ACE-Asia) campaign, March–May 2001. The measurements provide ground-based data at a western remote site of south Korea and characterize the long-range transport of O₃ over the Yellow Sea region during spring. The mean values of O₃ and NO₂ concentration at TAP were 42 ppb and 12 ppb, respectively. The average O₃ diurnal variation of 17 ppb at TAP indicates that the loss of O₃ was not pronounced during the night. The highest NO₂ concentrations, with an average diurnal variation of 8 ppb, occurred in the afternoon at 13–15 LST. The day-to-day variation of daily O₃ concentrations at TAP is strongly influenced by the movement of synoptic scale weather patterns. In general, the O₃ concentration in a southwesterly airflow tended to increase when a moving anticyclone crossed the site, ahead of a cold front. By contrast, north-northwesterly airflows associated with the passage of a cold front bring fresh continental outflow and decrease O₃ concentrations. Surface O₃ data at TAP were classified utilizing backward trajectory analysis based on the residence time, as well as the path of the airflows, in the boundary layer (1500 m asl) over the Yellow Sea region. The results show that north-northwest continental airflows, that were transported around Lake Baikal and eastern Mongolia at an altitude of approximately 3 km at relatively high speed and came straight down at TAP, represent continental background O₃ concentrations with a mean value of 29 ppb for this period. These airflows have a short period of residence of less than one day in the boundary layer over the Yellow Sea region. In contrast, the mean O₃ value of 45 ppb was observed in regionally polluted airflows mainly passing through the east-southeast part of China and remaining for 3 days, on average, in the Yellow Sea region. These three days residence time of the regionally polluted airflows over the Yellow Sea region allowed sufficient time for photochemical O₃ formation.  相似文献   

Concentration and deposition of trace metals in Ontario-1982     

Walter H. Chan  Al J. S. Tang  David H. S. Chung  Maris A. Lusis 《Water, air, and soil pollution》1986,29(4):373-389

Results of trace metal concentrations in air and precipitation and the corresponding wet and dry deposition in Ontario in 1982 arc reported. In terms of the spatial patterns, in general, there was a decreasing gradient from south-to-north in both concentration and deposition. Patterns differed with each parameter although certain groups of metals (e.g., Fe and Al; Pb, Zn, and Mn) displayed similar patterns. In general, wet deposition was greater than dry deposition at all sites. Geographically, the variability in the wet to dry deposition ratio for coarse particles (MMD > 2.5 μm) was small. However, it increased from the south to the north for fine particles (MMD < 2.5 μm), being higher away from the source areas. Scavenging ratios (W) have been derived from the precipitation and air concentrations of trace metals. The scatter in W is quite large for all trace metals, up to 2 orders of magnitude. There was little seasonal variability in W for fine particles (Pb, Mn, Zn, and Cd). However, coarse particles (Fe, Al, and Cu) were more efficiently scavenged by snow than by rain.  相似文献   

His-His-Leu, an angiotensin I converting enzyme inhibitory peptide derived from Korean soybean paste, exerts antihypertensive activity in vivo.   总被引：9，自引：0，他引：9  

Z I Shin  R Yu  S A Park  D K Chung  C W Ahn  H S Nam  K S Kim  H J Lee 《Journal of agricultural and food chemistry》2001,49(6):3004-3009

It has been reported that soybean peptide fractions isolated from Korean fermented soybean paste exert angiotensin I converting enzyme (ACE) inhibitory activity in vitro. In this study, further purification and identification of the most active fraction inhibiting ACE activity were performed, and its antihypertensive activity in vivo was confirmed. Subsequently, a novel ACE inhibitory peptide was isolated by preparative HPLC. The amino acid sequence of the isolated peptide was identified as His-His-Leu (HHL) by Edman degradation. The IC(50) value of the HHL for ACE activity was 2.2 microg/mL in vitro. Moreover, the synthetic tripeptide HHL (spHHL) resulted in a significant decrease of ACE activity in the aorta and led to lowered systolic blood pressure (SBP) in spontaneously hypertensive (SH) rats compared to control. Triple injections of spHHL, 5 mg/kg of body weight/injection resulted in a significant decrease of SBP by 61 mmHg (p < 0.01) after the third injection. These results demonstrated that the ACE inhibitory peptide HHL derived from Korean fermented soybean paste exerted antihypertensive activity in vivo.  相似文献   

Novel flavonol glycoside, 7-O-methyl mearnsitrin, from Sageretia theezans and its antioxidant effect     

Chung SK  Kim YC  Takaya Y  Terashima K  Niwa M 《Journal of agricultural and food chemistry》2004,52(15):4664-4668

A novel flavonol glycoside, 7-O-methylmearnsitrin (7,4'-O-dimethylmyricetin 3-O-alpha-L-rhamnopyranoside), and myricetrin, kaempferol 3-O-alpha-L-rhamnopyranoside, europetin 3-O-alpha-L-rhamnoside, and 7-O-methyl quercetin 3-O-alpha-L-rhamnopyranoside were isolated from the leaves of Sageretia theezans, and their chemical structures were identified by spectroscopic analyses including two-dimensional NMR (HSQC, HMBC). Whereas myricetrin, europetin 3-O-alpha-L-rhamnoside, and 7-O-methylquercetin 3-O-alpha-L-rhamnopyranoside showed stronger activities than ascorbic acid and alpha-tocopherol, 7-O-methylmearnsitrin showed very weak antioxidant activities by ESR and LDL oxidation inhibition tests.  相似文献   

Herbicidal Activity of Stylosanthes guianensis and its Phytotoxic Components     

T. D. Khanh  N. H. Hong  D. Q. Nhan  S. L. Kim  I. M. Chung  T. D. Xuan 《Journal of Agronomy and Crop Science》2006,192(6):427-433

Stylosanthes guianensis is a popular pasture legume and cover crop. The legume possessed strong allelopathic potential and suppressed spontaneous growth of paddy weeds. In a bioassay, aqueous extract of S. guianensis remarkably inhibited germination and growth of barnyardgrass and monochoria. Application of 1 ton ha^?1 upland parts of S. guianensis significantly reduced paddy weed biomass by 80 % and increased rice yield by 40 % when compared with the control. Gas chromatography‐mass spectrometry analysis reveals the presence of several allelochemicals in S. guianensis including phenolic acids, coumarin and long‐chain fatty acids. Stylosanthes guianensis may be used as a source of natural herbicide for reducing the dependency on synthetic herbicides in agricultural production.  相似文献   

Detection and differentiation of North American and European genotypes of porcine reproductive and respiratory syndrome virus in formalin-fixed, paraffin-embedded tissues by multiplex reverse transcription-nested polymerase chain reaction.     

Han-Kook Chung  Changsun Choi  Junghyun Kim  Chanhee Chae 《Journal of veterinary diagnostic investigation》2002,14(1):56-60

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IMMUNOGLOBULIN CLASSES IN SERUM ANTIBODY REACTIONS IN CATTLE FOLLOWING VACCINATION WITH BRUCELLA ABORTUS STRAIN 19 AND KILLED 45/20 VACCINES     

Y. S. Chung    W. T. K. Hall  G. C. Simmons 《Australian veterinary journal》1980,56(9):413-416

SUMMARY A group of 4 cows was vaccinated with Brucella abortus strain 19, followed 8 weeks later by a single dose of B. abortus 45/20 vaccine. A similar group received 2 doses of B. abortus 45/20 vaccine 8 weeks apart. The antibody responses of the groups were compared by testing whole serums and separated IgM and IgG fractions by the Rose Bengal Plate (RBP) agglutination and the complement fixation tests (CFT) using rough and smooth B. abortus antigens. Animals that had received B. abortus strain 19 responded to the 45/20 vaccine with increased titres to the smooth antigen. These relevant antibodies were predominantly of the IgG class. Standard CFT and RBP test antibodies could be detected in IgM and IgG fractions after the primary inoculation with B. abortus strain 19 vaccine.  相似文献   

Evaluation of a regimen using a progesterone releasing intravaginal device (CIDR) and PMSG as a treatment for post partum anoestrus in dairy cattle     

TF. JUBB  P. BRIGHTLING  J. MALMO†  MT. LARCOMBE  GA. ANDERSON  SJ. HIDES‡ 《Australian veterinary journal》1989,66(10):334-336

Anoestrous dairy cows in seasonally calving herds in the Macalister Irrigation District of Gippsland, Victoria were treated at the start of the mating period with a progesterone releasing intravaginal device (CIDR). The CIDR was inserted for 7 days and 400 IU of PMSG was injected intramuscularly at removal. There was no clinically useful difference among cows receiving the CIDR, a placebo and untreated cows in the interval from treatment to either first oestrus or conception, the conception rate to first service or percent pregnant by the end of mating. Analyses of data from 2-year-old cows, older cattle, cows calved at least 45 days or cows calved at least 55 days and cows treated 3 weeks after the start of mating did not show improved reproductive performance following treatment with the CIDR.  相似文献   

An attempt to prevent acute toxoplasmosis in macropods by vaccination with Hammondia hammondi     

GL REDDACLIFF  SJ PARKER  JP DUBEY  PJ NICHOLLS  AM JOHNSON  DW COOPER 《Australian veterinary journal》1993,70(1):33-35

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Assessment of tetracycline and Babesia culture supernatant as prophylactics for moderating reactions in cattle to live Babesia and Anaplasma vaccines     

WK JORGENSEN  RE BOCK  TG KINGSTON  AJ DE VOS  SJ WALDRON 《Australian veterinary journal》1993,70(1):35-36

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