• The Korean Journal of Physiology
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• v.24 no.1
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• pp.161-170
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• 1990

The effects of $H^{+}$ on the arterial contraction and their mechanisms were investigated in the renal artery of a rabbit. The helical strips of isolated renal artery were immersed in the HEPES-buffered or $CO_{2}/HCO_{3}^{-}$-buffered Tyrode's solution. The contractions induced by agonists (norepinephrine, histamine, serotonin and angiotensin II) or high $K^{+}$ were observed with change of extracellular or intracellular $H^{+}$ concentration. The contractions induced by norepinephrine, histamine, serotonin, angiotensin II or high $K^{+}$ in HEPES-buffered Tyrode's solution were inhibited by increase in extracellular $H^{+}$ concentration and potentiated by decrease in extracellular $H^{+}$ concentration. The degrees of these effects were most evident in the contraction induced by serotonin and angiotensin II, moderate in those by histamine and high $K^{+}$, and least in those by norepinephrine. Maximal contraction by norepinephrine, histamine and high $K^{+}$ were not influenced by change in extracellular $H^{+}$ concentration, but influenced in those contration by serotonin and angiotensin II. The attenuated contractions by an acidic pH were not returned to the level of contraction at normal pH (7.4) by elevation of extracellular $Ca{2+}$ concentration. The agonists (norepinephrine, histamine and serotonin)-induced contractions in $Ca{2+}$-free Tyrode's solution were also attenuated by increase in extracellular $H^{+}$ concentration and potentiated by decrease in extracellular $H^{+}$ concentration. Elevation of $Pco_{2}$ in the $CO_{2}/HCO_{3}^{-}$-buffered Tyrode's solution, which increase the intracellular $H^{+}$ concentration, at constant extracellular pH (7.4), increased the contraction by 30 mM $K^{+}$. From the above results, it is suggested that the decrease in contractions by increase in extracellular $H^{+}$ concentration may be resulted from that $H^{+}$ make the receptors less sensitive to agonists and cell membrane hyperpolarize and then inhibit the $Ca{2+}$ influx as well as $Ca{2+}$ release from intracellular $Ca{2+}$ storage site.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.51-65
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• 1990

The purpose of the present study was to examine the hemodynamic responses, especially in arterial and skin blood flows, in conjunction with the changes of plasma catecholamine levels as an indirect marker of adrenergic tone during the early stage of head-down tilt (HDT), and to evaluate the early physiological regulatory mechanism in simulated weightlessness. Ten mongrel dogs, weighing8\;{\sim}\;14\;kg, were intravenously anesthetized with nembutal, and postural changes were performed by using the tilting table. The postural changes were performed in the following order: supine, prone, HDT $(-6^{\circ}C)$ and lastly recovery prone position. The duration of each position was 30 minutes. The measurements were made before, during and after each postural change. The arterial blood flow $({\.{Q}})$ at the left common carotid and right brachial arteries was measured by the electromagnetic flowmeter. Blood pressure (BP) was directly measured by pressure transducer in the left brachial artery. To evaluate the peripheral blood flow, skin blood flow $({\.{Q}})$ was calculated by the percent changes of photoelectric pulse amplitude on the forepaw, and skin temperature was recorded. The peripheral vascular resistance (PR) was calculated by dividing respective mean BP values by ${\.{Q}}$ of both sides of common carotid and brachial arteries. Heart rate (HR), respiratory rate (f) and PH, $Po_{2},\;Pco_{2}$ and hematocrit of arterial and venous blood were also measured. The concentration of plasma epinephrine and norepinephrine was measured by radioenzymatic method. The results are summarized as follows: Tilting to head-down position from prone position, HR was initially increased (p<0.05) and BP was not significantly changed. While ${\.{Q}}$ of the common carotid artery was decreased (p<0.05) and PR through the head was increased, ${\.{Q}}$ of the brachial artery was increased (p<0.05) and PR through forelimbs was decreased. ${\.{Q}}$ of the forepaw was initially increased (p<0.05) and then slightly decreased, on the whole revealing an increasing trend. Plasma norepinephrine was slightly decreased and the epinephrine was slightly increased. f was increased and arterial pH was increased (p<0.05). In conclusion, the central blood pooling during HDT shows an increased HR via Bainbridge reflex and an increased ${\.{Q}}$ of the forepaw and brachial ${\.{Q}}$, due to decreased PR which may be originated from the depressor reflex of cardiopulmonary baroreceptors. It is suggested that the blood flow to the brain was adequately regulated throughout HDT $(-6^{\circ}C)$ in spite of central blood pooling. And it is apparent that the changes of plasma norepinephrine level are inversely proportional to those of ${\.{Q}}$ of the forepaw, and the changes of epinephrine level are paralleled with those of the brachial ${\.{Q}}$.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.123-129
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• 1990

A comparative study of acid-base balance has been made between acidemia-induced hyperkalemia and hyperkalemia-induced acidemia. A group of rabbits was infused 0.1 N hydrochloric acid solution and metabolic acidosis was induced. Another group was administered 20 mM potassium chloride solution and hyperkalemia was induced. The third group was infused 0.1 N hydrochloric acid and 20 mM potassium chloride solution, simultaneously. Acid-base data and plasma potassium ion concentration were monitored every thirty minutes in these three groups of rabbits. Following results were obtained: 1 ) Along with the infusion of hydrochloric acid, acute metabolic acidosis was induced in the rabbits. Plasma bicarbonate ion concentration decreased primarily in this group. As a respiratory compensation, there was a tendency of reduction of arterial $Pco_{2}$. The alteration of data became larger along with the amount of administration and the time elapsed. However, hyperkalemia was not so severe compared with the second group. 2) In potassium chloride infused group, plasma potassium ion concentration increased along with the time elapsed and the amount of infusion. And the alteration of acid-base data was parrallel to the level of potassium ion concentration, above all depression of pH was prominent. 3) Above data suggest that when acute metabolic acidosis was induced, exchange of intracellular potassium ion with extracellular hydrogen ion seems significant for the regulation of extracellular acid-base balance. And when hyperkalemia was induced with the infusion of potassium chloride solution, the exchange of intracellular hydrogen ion with extracellular potassium ion also seems significant for the regulation of extracellular potassium balance. 4) In the group of rabbits infused hydrochloric acid and potassium simultaneously, disturbances of acid-base balance and potassium balance were much more severe than two other groups. In these mixed disturbances, the process of compensatory mechanism might be inhibited and one disturbance might aggregate each other. 5) Through above data it has been postulated that in acid-base disturbance potassium balance can be sacrificed as a compensatory mechanism, and vice versa in disturbance of potassium balance. And our data also suggest that hydrogen ion and potassium ion are compensatory pair, one another.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.364-364
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• 2017

Saemangeum reclaimed land is a part of Saemangeum Development Project. Most of the persistent problems of Saemangeum reclaimed land remain to be related to soil salinity. Soil salinity is a major abiotic factor related to microbial community structure and also fungi have been reported to be more sensitive to salinity stress than bacteria. The aim of this study was conducted to investigate the effect of soil salinity levels on the microbial communities in Saemangeum reclaimed land using 454 pyrosequencing analysis. Soil samples was collected from 12 sites of in Saemangeum reclaimed land. For pyrosequencing, 27F/518R (bacteria) and ITS3/ITS4 (fungi) primers were used containing the Roche 454 pyrosequencing adaptor-key-linker (underlined) and unique barcodes (X). Pyrosequencing was performed by Chun's Lab (Seoul, Korea) using the standard shotgun sequencing reagents and a 454 GS FLX Titanium sequencing System (Roche, Inc.). In the soil samples, Proteobacteria (bacteria) and Ascomycota (fungi) shows the highest relative abundance in all the soil sample sites. Proteobacteria, Bacteroidetes, Plantomycetes, Gemmatimonadetes and Parcubacteria were shown to have significantly higher abundance in high salinity level soils than low salinity level soils, while Acidobacteria and Nitrospirae has significantly higher relative abundance in low salinity level soils. The abundance of fungal, Ascomycota has the highest relative abundance in soil samples, followed by Basidiomycota, Chlorophyta, Zygomycota and Chytridiomycota. Basidiomycota, Zygomycota, Glomeromycota and Cerozoa were show significantly higher relative abundance in low salinity level soils. The principal coordinate analysis (PCoA) and correlation analysis shown to salinity-related soil parameters such as ECe, Na+, SAR and EPS were affected to bacterial and fungal community structure. Proteobacteria, Bacteroidetes, Plantomycetes exhibited significantly positive correlation with soil salinity, while Acidobacteria exhibited significantly negative correlation. In the case of fungal community, Basidiomycota and Zygomycota were seen show significantly negative correlation with salinity related soil parameters. These results suggest that provide understanding effect of soil salinity on microbial community structure and correlation of microbial community with soil parameters in Saemangeum reclaimed land.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.266-273
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• 2002

A total of 225 day-old broiler chicks (43.08 g initial body weight) were allotted to three dietary treatments for a 6-week feeding trial. The treatments were 1) Control (defatted rice bran; DFRB), 2) fresh rice bran (FRB) and 3) rancid rice bran (RRB). Rice brans were intentionally spoiled by two degrees of rancidity by the values of free fatty acids (FFA): 7.6% (FRB) and 16.3% (RRB). Diets were prepared on an isonutrient basis, and defatted or rancid rice brans were included 5 and 10% for starter (0-3 week) and finisher (3-6 week), respectively. At the end of the feeding trial, six chicks per treatment were sacrificed, and thigh meats were ground and stored at $1^{\circ}C$ for thiobarbituric acid reactive substances (TBARS) and peroxide value (POV) analyses. For a digestibility, 48 growing chicks (4 weeks old) were employed in cages (3 replicates/treatment, 2 birds/cage) according to the experimental design: FRB, RRB, pelleted and extruded rice bran. Some of the FRB were pelleted ($70^{\circ}C$) or extruded ($110^{\circ}C$). There was no significant difference in growth performance during the starter period, but chicks fed a diet containing DFRB grew faster (p<0.05) with increased feed intake (p<0.05) than those fed diets containing rice brans, FRB or RRB, during the finisher period. Feed conversion ratio in the RRB was inferior (p<0.05) to the DFRB. Between rice bran groups, weight gain was higher (pco.os) in FRB than in RRB during finisher period. There was a similar trend in growth performance of chicks for the overall period (0-6 week) as the finisher period. Dry matter and energy digestibilities were higher (p<0.05) in extruded than in RRB group. Protein digestibility was improved (p<0.05) when rice bran was extruded, but not pelleted. The chicken meats from RRB showed higher (p<0.05) TBARS than those from FRB during storage for 4 weeks at $1^{\circ}C$. In conclusion, it would appear that feeding rancid rice bran gave negative effects on growth performance and lipid stability of meat in broiler chicks.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.360-367
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• 2010

The genetic diversity and structure of P. tongkangensis in 5 populations from 3 regions was investigated using 56 markers derived from 6 ISSR primers. Genetic diversity at the species level (P=94.6, SI=0.377, h=0.240) was substantial considering the limited distribution and small size of populations. Genetic differentiation among regions (12%) and among populations (13%) in the region was not clearly evident, which suggested a moderate level of gene flow among adjacent populations. The Mantel test revealed a significant correlation between genetic differentiation (${\Phi}_{ST}$) and geographic distance among populations. This was supported by cluster analysis and principal coordinate analysis (PCoA). The significant difference in marker band frequency at many loci and their fixation in opposite directions in the smallest and most isolated population SC were considered due to genetic drift. Therefore, the genetic diversity of P. tongkangensis could be compromised if the distribution area or the size of the population was further reduced. In particular, small and isolated populations could be at great risk of extinction. Considering this, the unique habitats of P. tongkangensis should be protected and the reduction of population size should be closely monitored. Conservation efforts including the seeding and planting of seedlings should be done carefully based on their genetic and ecological traits. Our data support the argument that establishing an integrated management system for the efficient conservation of P. tongkangensis is critical.

• Journal of Veterinary Clinics
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• v.25 no.5
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• pp.359-362
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• 2008

This study examined the efficacy of needle-acupuncture (AP) at Nei Guan (PC06) and Xin Shu (BL15) on canine tachycardia. A total of 18 beagle dogs were divided into three groups: a control (6 heads), PC06 (6 heads) and PC06 (6 heads) group. Tachycardia was induced by an intramuscular injection of glycopyrrolate. No treatment was given to the control group. Needle-AP at PC06 and BL15 were applied simultaneously at the same time as the glycopyrrolate injection for 20 minutes in PC06 and BL15 groups, respectively. The changes in R-R intervals and respiration rates were determined. The changes in the R-R intervals in the PC06 and BL15 groups were significantly higher than the control group. The R-R intervals of the BL15 group were significantly higher than in the PC06 group. The changes in the respiration rates in the PC06 group were similar to those of the control group. However, the respiration rates in the BL15 group were significantly lower than the control and PC06 groups. In conclusion, needle-AP at PC06 and BL15 is effective in assisting in the recovery from induced canine tachycardia. However, needle-AP at BL15 is more effective than that at PC06.

• The Korean Journal of Ecology
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• v.28 no.1
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• pp.15-23
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• 2005

The black locust (Robinia pseudoacacia L.) forests were studied by a phytosociological approach. Particular attention was given to characterize the vegetation classification, distribution pattern, and ecological flora of the syntaxa classified. A total of 38 releves were analyzed by using Correlation coefficient, UPGMA as the clustering method, and Principal Coordinates Analysis for ordination. Ecological flora analyzed by plant character sets such as scrambler, annual and biennial plants, forest elements, and actual urbanization index. The analyzed data are based on site-releve matrix with relative net contribution degree (r-NCD) of species. A total of 77 families, 193 genera and 323 species of vascular plants are recorded. Camellino-Robinietum pseudoacaciae ass. nov. and Phragmites-Robinia pseudoacacia community were described. Main cluster and ordination could be separated: 1) urban type, 2) rural type, 3) riparian type, and 4) combined type. It is defined that the Robinietum is a representative unit on the black locust afforestation, Phragmites-Robinia community on the lentic zone in the river ecosystem, and Cameliino-Robinietum ailanthetosum altissimae as an urban forest type. The Robinietum was considered as a perpetual community.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.687-700
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• 2014

Rice blast (Magnaporthe oryza B.) is one of the most important diseases in rice that causing great yield losses every year around the world. It is important to screen valuable genetic resources for improving blast resistance. This study was conducted to identify the blast resistance in 279 Korean rice landraces using blast nursery tests and isolate inoculum screening. The results showed that 11 landrace accessions found to be resistant to rice blast in blast nursery and inoculation screening tests and the degree of lesions in most accessions showed that they were susceptible to reactions. In order to find the distribution of blast resistant genes, a molecular survey was conducted to identify the presence of major blast resistance (R) gene in 279 Korean landraces. The results revealed that their frequency distribution was Pik-m (36.2%), Piz (25.4%), Pit (13.6%), and Pik (10%). Besides, the frequency distribution of Piz-t, Pii, Pik-m/Pik-p, Pi-39(t), Pib, Pi-d(t)2, Pita/Pita-2 and Pi-ta genes were identified as less than 10%. The results did not consist with the reactions against blast diseases between genotypes and phenotypic part of the nursery tests and isolate inoculation. For concluding these results, we used genome-wide SSR markers that have closely been located with resistance genes. The PCoA analysis showed that the landrace accessions formed largely two distinct groups according to their degree of blast resistance. By comparing genetic diversities using polymorphic information contents (PIC) value among the resistant, total and susceptible landraces, we found that PIC values decreased in four SSR markers and increased in six markers in the resistant accessions, which showed contrary to total and susceptible groups. These regions might be linked to resistance alleles. In this study, we evaluated the degree of blast resistance and the information about the distribution of rice blast resistant genes in Korean rice landraces. This study might be the basis for association analysis of blast resistance in rice.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.469-477
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• 2010

The purpose of this study was to evaluate the effects of insole-equipped ankle-foot-orthoses (AFO) on gait. 10 healthy males who had no history of injury in the lower extremity participated in this study as the subjects. The foot of each subject was first scanned, and the insole fit to the plantar was made using BDI-PCO(Pedcad Gmbh, Germany). The subject then was made to walk on a treadmill under four experimental conditions: 1) normal walking, 2) walking wearing AFO, 3) walking wearing AFO equipped with the insole, 4) walking wearing pneumatic-ankle-foot-orthosis (pAFO) equipped with the insole. During walking, foot pressure data such as maximum force, contacting area, peak pressure, and mean pressure was collected using Pedar-X system (Novel Gmbh, Germany) and EMG activity of lower limb muscles such as gastrocnemius medial head, gastrocnemius lateral head, and soleus was recorded using MP150 EMG module (BIOPAC System Inc., USA). Collected data was then analyzed using paired t-test in order to investigate the effects of the insole. As a result of the analysis, when insole was equipped, overall contacting area was increased while both the highest peak pressure and the mean pressure were significantly decreased, and EMG activity of the lower limb muscles was decreased. On the contrary, the cases of wearing AFO showed the decreased contacting area and the increased pressures. Therefore, the AFO equipped with a proper insole fit well to the foot can help comfortable walking by spreading the pressure over the entire plantar.