• Title/Summary/Keyword: LT$_{50}$

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Changes of Tree Growth and Fruit Quality of "Yumi" Peach under Long-Term Soil Water Deficit

  • Yun, Seok Kyu;Kim, Sung Jong;Nam, Eun Young;Kwon, Jung Hyun;Chung, Kyeong Ho;Choi, In Myung;Kim, Ghiseok;Shin, Hyunsuk
    • Journal of Biosystems Engineering
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    • v.42 no.4
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    • pp.276-282
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    • 2017
  • Purpose: This paper presents the effects of soil drought stress during the growing season and pre-harvest period on tree growth and fruit quality of "Yumi" peach, an early season cultivar. Methods: Soil drought stresses were treated with four levels of -30, -50, -60, and -70 kPa during long term (LT) and short term (ST). For LT treatments, soil water was controlled for nine weeks from May 1 to July 5, which was assumed as the full growing season. For ST treatments, soil water was controlled for four weeks from June 10 to July 5, which was assumed as the pre-harvest season. Tree growth and leaf photosynthesis were measured, and fruit characteristics such as fruit weight and diameter, soluble solid and tannin contents, and harvest date were investigated. Results: Soil water deficit treatments caused a significant reduction in tree growth, leaf photosynthesis, and fruit enlargement. LT water stress over -60 kPa during the full growing season caused significant reduction in tree growth, including shoot length, trunk girth, leaf photosynthesis, and fruit enlargement. ST water stress over -60 kPa during the pre-harvest period also induced significant reduction in leaf photosynthesis and fruit enlargement, while tree growth was not reduced. In terms of fruit quality, water stress over -50 kPa significantly reduced fruit weight, increased soluble solid and tannin contents, and delayed harvest time in both LT and ST treatments. Conclusions: As a result, it is assumed that LT water stress over -60 kPa can reduce both tree growth and fruit enlargement, whereas ST water stress over -50 kPa can reduce fruit enlargement without reducing tree growth. From an agricultural perspective, moderate water deficit like -50 kPa treatments could have positive effects, such increased fruit soluble solid contents along with minimal reduction in fruit size.

Acute and Chronic Toxicity of Phenol to Mysid, Archaeomysis kokuboi (곤쟁이, Archaeomysis kokuboi에 미치는 phenol의 급성 및 만성독성)

  • KIM Jeong-Seon;CHIN Pyung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.28 no.1
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    • pp.87-97
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    • 1995
  • Acute and chronic toxicity of phenol on the mortality, long-term survival and respiration rates of the mysid, Archaeomysis kokuboi adult and juvenile were examined. This experiment was condurted by static bioassay procedure with the different salinity at $25^{\circ}C$ In lethal test, the test animals were exposed to 6 different phenol concentrations to determine $LC_{50}$ and I$LT_{50}$ (median lethal concentration and time) values. The $LC_{50}$ values with the exposure time for the mysid adult ranged from 31.31ppm to 1.49ppm phenol and for the mysid juvenile ranged from 6.90ppm to 0.26ppm in all experimental groups. Mortality was increased with the decrease of salinity, The $96hr-LC_{50}$ values at 16, 24 and $32\%o$ salinity for the mysid adult were 1.49, 2.71 and 4.53ppm phenol, white the values for the mysid juvenile were 0.26, 0.56 and 0.71ppm, respectively. The ratios of $96hr-LC_{50}$ values for the mysid adult to those for the mysid juvenile at 16, 24 and $32\%p$ salinity were 5.73, 4.84 and 6.38, respectively. The mysid juveniles were more sensitive to phenol than the mysid adults. Compared $LT_{50}$ values for the mysid adult with those for the mysid juvenile, the $LT_{50}$ values for the mysid adult ranged from 384.7 to 29.0 hours at 1.7-127ppm phenol concentrations and for the mysid juvenile ranged from 132.2 to 18.7 hours at 0.5~6.Oppm phenol concentrations. The lowest $LT_{50}$ values for the mysid adult and juvenile were showed at the combination of the highest experimental concentration of phenol and the lowest experimental salinity. The mysid juveniles showed lower $LT_{50}$ values than those of adults. The chronic effects of phenol on the mysid at the sublethal effective concentration of phenol were lower in the $32\%o$ salinitr group than 16 or $24\%o$ salinity groups. Oxygen consumption rates of the mysid adult were decreased with the increase of phenol concentration and exposure time, and decreased significantly in lower salinity at the same concentration or phenol.

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Improvement of Particleboard Manufacturing Process and its Properties Using Powdered Tannin Adhesives (분말상 탄닌수지를 이용한 파티클보드 제조기술 및 물성개선)

  • Kang, Seog Goo;Lee, Hwa Hyoung
    • Journal of the Korean Wood Science and Technology
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    • v.32 no.1
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    • pp.80-87
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    • 2004
  • This study was carried out to improve the properties of powdered tannin adhesive(PT) by adding liquid tannin resin(LT) to PT in the manufacture of particleboard. Mixing the LT to PT from 50% to 100% by weight did not show any difference in particleboard properties, but the higher the powdered tannin resin ratio, the lower the properties of the board. The proper ratio of PT to LT was 30:70 for the improvement of PT-particleboard, unless LT lower than 70%. Internal bonding strength was in proportional to the amount of LT. Mixing amino adhesives and PT did not show any improvements in mechanical and physical properties of the board but they only acted as scavenger for the free formaldehyde.Manufacturing particle board with the adhesive of 30:70 (PT:LT) and by using double blender resulted in high-performance products of E0 level of formaldehyde emission with high water resistance (U type; below 12%, M type; below 25%), as well as saving chip drying energy.

Bioassays On marine Organisms: Acute Toxicity Test Of mercury, Cadmium And Copper To Arkshell, Anadara broughtonii, From Jin-Dong Bay, And To Oyster, Crassostrea gigas, From Kwang-Do Bay, South Coast Of Korea

  • Park, Joo-Suck;Kim, Hak-Gyoon
    • 한국해양학회지
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    • v.13 no.1
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    • pp.35-43
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    • 1978
  • Short-term acute toxicity of mercury, cadmium and copper to arkshell, Anadara broughtonii, and to oyster, Crassostrea gigas, was determinedby static bioassays from 20 May to 27 June in 1977. During the observations of the opening rate of the shell mercury was the most sensitive toxicant of the three toxic substances to the test animals and caused them to close their shellvalves together after being exposed to a mercury solution for an hour during the test. Opening rate to cadmium and copper increased gradually at the higher concentration. the 96hr-LC50 values for the test animals are 4.84mg/l for mercury and 1.86mg/l for cadmium, while the 72hr-LC50 value for copper is 0.31mg/l. the death rate of oysters for cadmium showed lower than that of the mercury and copper test solutions. The 96hr-LC50 values of mercury, copper and cadmium were 1.1mg/l, 2.54mg/l and 19.5mg/l, respectively. For oysters mercury was the most toxic substance, and cadmium was the least toxic one. the medium lethal time (LT 50) value decreased gradually at higher concentration of heavy metals. The LT 50 of 2mg/l was found within 96 hours ofr copper, 104 hours for mercury and 121 hours for cadmium. The lethal threshold concentrations for 7 days were found to be about 1mg/l for mercury and copper, and 2mg/l for cadmium.

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Fatigue and weakness hinder patient social reintegration after liver transplantation

  • Kang, So Hyun;Choi, YoungRok;Han, Ho-Seong;Yoon, Yoo-Seok;Cho, Jai Young;Kim, Sungho;Kim, Kil Hwan;Hyun, In Gun;Shehta, Ahmed
    • Clinical and Molecular Hepatology
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    • v.24 no.4
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    • pp.402-408
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    • 2018
  • Background/Aims: With improvements in the survival of liver transplantation (LT) recipients, the focus is shifting to patient quality of life (QOL), and employment is an important factor in aiding the social reintegration of LT patients. This study aims to evaluate the current employment status of liver graft recipients and various factors that may hinder reemployment. Methods: Fifty patients above age 18 who underwent either living or deceased donor LT at a single center from March 2009 to July 2016 were interviewed during their visit to the outpatient clinic. The internally developed questionnaire consisted of 10 items. The Karnofsky Performance Scale and EQ-5D were used to evaluate patient function and QOL. Results: A total of 25 (50%) patients returned to work after transplantation (the working group), and 21 (84%) patients in the working group returned to work within the first year after transplantation. In the non-working group (n=25), 17 (68%) answered that their health was the reason for unemployment. Fatigue and weakness were the most frequent symptoms. Conclusions: The data shows that as many as 50% of total patients returned to work after receiving LT. Fatigue and weakness were the most common complaints of the unemployed group, and resolving the causes of these symptoms may help to increase the employment rate.

The Results of Various Vestibular Function Tests in Young Male Adult (장정에 시행한 몇가지 평가기능 검사성적에 대한 고찰)

  • 박찬일;추광철;노관택
    • Proceedings of the KOR-BRONCHOESO Conference
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    • 1972.03a
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    • pp.2.3-2
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    • 1972
  • The vestibular function test reveals the objective findings of the impairment of the vestibular labyrinth. It's purpose is based on the analysis of the findings and detect the location and etiology of the labyrinthine impairment. In the vestibular function test, the vestibulo-spinal reflex has the clinical significance upon the tonus of the striated muscles by the labyrithine stimulation and contribute to regulating the posture and the position, at rest as well as in motion. The vestibulo-spinal reflex must performe as one of the routine vestivular function test because it can be evoked in man by such weak stimuli to the labyrinth as cannot induce vestibulo-ocular reflex. Authors performed the vestibular function test such as one leg test, gait test, stepping test and vertical writing test to one hundred of healthy and young male adult and received the following results. Results 1. One leg test: In 30 seconds, the frequency of dropping the leg on the ground was between 0 to 3 times in Rt., and 0 to 5 times in Lt. The mean frequency was 0.48 times in Rt., and 0.68 times in Lt. 2. Gait test: In forward gait; the range of the deviation was distributed 0 to 100 cm and mean range was 22.5cm to the Rt., 26.1cm to the Lt. In backward gait; the range deviation was distributed 0 to 140cm and mean range was 35.4cm to the Rt., 33.0cm to the Lt. 3. Stepping test: In normal head position; forward movement war 93% and backward 5%. The angle of displacement deviated to the Rt. side in 36%, and Lt. in 50%. The angle of rotation deviated to the Rt. side in 53 %, and Lt. in 36%. The mean values: angle of displacement was 22.05 degrees, angle of rotation was 24.40 degrees, distance of displacement was 48.95cm. In backward head position; Forward movement was 94% and backward was 3%. The angle of displacement deviated in 34%, and Rt. in 55%, to the Rt. side The angle of rotation deviated to the Rt. side in 50%, and Lt. in 42%. The mean values; angle of displacement was 29.72 degrees, angle of rotation was 39.53 degrees, distance of displacement was 44.17cm. 44.17cm. 4. Vertical writing test: The angle of deviation was between 0 to 16 degrees in all cases, and was between 0 to 12 degrees in the cases of normal head position. The mean angle of deviation was between 4.15 to 5.76 degrees on each side. The direction of deviation to the Rt. side was 54~69%, Lt. was 25~40% and 3~7% was vertical without deviation.

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Zinc Deficiency Elevates Fecal Protein, But Not Electrolyte and Short-Chain Fatty Acid, Levels in Enterotoxigenic Escherichia coli-Induced Diarrhea in Rats

  • David, Ebuka E.;Yameen, Muhammad A.;Igwenyi, Ikechuku O.;David, Chidinma N.;Nwobodo, Valentine;Ismail, Akindele K.
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.25 no.1
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    • pp.79-86
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    • 2022
  • Purpose: To determine the effect of zinc deficiency on fecal protein, electrolyte, and short-chain fatty acid levels in both heat-stable (ST) and heat-labile (LT) enterotoxigenic Escherichia coli (ETEC)-induced diarrhea in rats. Methods: Albino rats, weighing 100 to 150 g, were divided into 2 groups, with 15 animals each: non-zinc and zinc-deficient. These two groups were sub-divided into three sub-groups with five rats each: control (saline); LT-ETEC; and ST-ETEC. Sodium phytate (30 mmol/L) was added to the animals' water to induce zinc deficiency, while diarrhea was induced using 5×109 ETEC cells/mL. Fecal protein levels were estimated using the Bradford method, while sodium and potassium levels were determined using atomic absorption spectrophotometry. Short-chain fatty acids were measured using gas chromatography-mass spectrometry. Results: Among the non-zinc and zinc-deficient groups, there were significant increases (p=0.04), (p=0.03) in fecal protein concentrations (mg/mL) in the LT-ETEC- (4.50±0.33), (6.50±0.26) and ST-ETEC- (3.85±0.19), (5.98±0.32) induced groups compared to the control groups (2.60±0.52), (3.50±0.11) respectively. Fecal sodium and potassium levels (mg/L) were significantly (p=0.029) increased in non-zinc-deficient rats induced with LT-ETEC (9.35±0.95, 1.05±0.48), and ST-ETEC (9.96±1.02, 1.21±0.45) compared with the control group (8.07±0.44, 0.47±0.17) but the increase were not statistically significant (p=0.059) in the zinc deficient rat groups. Fecal acetate and propionate levels (mg/g) significantly (p=0.032) increased when induced with LT-ETEC and ST-ETEC in non-zinc and zinc-deficient groups compared with the control groups. Conclusion: Zinc deficiency among rats with ETEC-induced diarrhea elevated fecal protein loss but may not have an effect on fecal sodium, potassium and short-chain fatty acid levels.

Changes in forest fire fuel amount in a Chamaecyparis obtusa forest according to stand density control (편백림 임분밀도 조절에 따른 유기물층의 산불 연료량 변화)

  • Du-Hee Lee;Jeong-Gwan Lee;Han Doo Shin;Sle-Gee Lee;Woo Jin Park;Hyun-Jun Kim
    • Korean Journal of Environmental Biology
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    • v.41 no.4
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    • pp.447-454
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    • 2023
  • This study was conducted to analyze the effects of stand density on fire fuel (FF) changes in a Chamaecyparis obtusa forest. The study site was located in Mt. Munsu in Jeollabuk-do and consisted of a control, 30% thinning treatment(LT), and 50% thinning treatment(HT). Three-year-old seedlings were planted at a density of 3,000trees ha-1 in 1976, and thinning was carried out in 2000. FF production was measured every 2 months by installing 3 circular litter traps 1.2m above the ground. Litter bags containing 5g of each leaf and branch were made and buried in the organic layer to investigate the FF decomposition rate. The decay constant was calculated after 18 months. FF accumulation was measured by collecting dry-weight organic matter from each plot using a square frame (0.09 m2) in September 2018. The FF production in LT and HT was significantly lower than that of the control(P<0.001). The leaf decay constant for HT was significantly lower than that of the control (P<0.05). The FF accumulation in HT was significantly lower than that of the control (P<0.01), but LT was not significantly different from the control. The results of this study showed that thinning decreased FF production.

Screening of Korean Herbal Medicines with Inhibitory Activity on Advanced Glycation End Products Formation (IX) (한국약용식물의 최종당화산물 생성저해활성 검색 (IX))

  • Lee, Yun Mi;Kim, Young Sook;Kim, Joo Hwan;Kim, Jin Sook
    • Korean Journal of Pharmacognosy
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    • v.44 no.3
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    • pp.298-304
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    • 2013
  • In this study, 64 Korean herbal medicines have been investigated with an in vitro evaluation systems using glycation end products (AGEs) formation inhibitory activity. Of these, 30 herbal medicines ($IC_{50}&lt;50{\mu}g/ml$) were found to have significant AGEs formation inhibitory activity. Of these, four herbal medicines ($IC_{50}&lt;5{\mu}g/ml$) were found to have significant AGEs formation inhibitory activity. Particularly, Cornus controversa (branches and leaves), Acer ginnala (stems and leaves), Platycarya strobilacea (flowers) and Picrasma quassioides (stems), showed more potent inhibitory activity (approximately 17-27 fold) than the positive control aminoguanidine ($IC_{50}=77.04{\mu}g/ml$).

The Shape and the Location of Forehead Hairline of Korean Males in Their 20s & 30s (20, 30대 한국 남성의 전두부 모발선의 모양과 위치)

  • Yoon, Sung-Won;Kim, Chung-Hun
    • Archives of Plastic Surgery
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    • v.38 no.3
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    • pp.295-299
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    • 2011
  • Purpose: It is generally believed that alopecia is caused by various factors such as scars, stress, genetical factors, androgens, etc. Androgenic alopecia is one of the most common cause of alopecia and found mainly in males. Propecia (Merck & Co., USA) and Minoxidil (McNEIL-PPC, Inc, USA) were the drugs approved from FDA for treatment of androgenic alopecia. Surgical treatments such as flap, tissue expansion, scalp reduction and hair transplantation can be considered if necessary. Hair micrograft techniques were developed for natural hair shapes and minimal adverse effect. There were attempts to measure the length of the forehead of the Korean young adults. However attempts to classify the shape and location of forehead hairline were rare. This study attempted to find out standard hairlines of young adults in their 20s & 30s and the result would be the guideline of the hairline in hair replacement surgery of male patients in their 40s & 50s. Methods: 200 male adults in 20s and 30s were photographed and measured the length of 11 vertical index lines to determine hairline. The indexes are the distances from hairline to intercanthal midpoint (A), to medial canthus (B), to upper eyelid fissure (C), to lower eyelid fissure (D), to lateral canthus (E) and distance from lateral highest point to medial lowest point, if the hairline is M-shape (F). Additionally, we classified the hairlines into 4 groups, M, horizontal, inverted U and irregular shapes. Results: The most common hairline of male adults in their 20s is inverted U-shape (53.3%), followed by horizontal-shape, M-shape, irregular-shape. In their 30s, inverted U-shape (59%) is followed by irregular-shape, M-shape, horizontal-shape. The M-shape is more frequently found in males in 30s than those in 20s. The mean values of the indexes in their 20s are as follows: A (76.14 mm), B (Rt: 75.78 mm, Lt:76.41 mm), C (Rt: 69.43 mm, Lt: 69.92 mm), D (Rt: 76.92 mm, Lt:77.46 mm), E (Rt: 64.16 mm, Lt: 64.73 mm), F (4.09 mm). Those in their 30s are as follows: A (76.13 mm), B (Rt: 76.114 mm, Lt: 76.02 mm), C (Rt: 69.87 mm, Lt: 70.37 mm), D (Rt: 77.37 mm, Lt: 77.58 mm), E (Rt: 69.63 mm, Lt: 69.85 mm), F (6.14 mm). Conclusion: The knowledge about human body measurement is indispensable to plastic surgeons. In this study, inverted U shape is the most common type of hairline in 30s, and similar distribution is found in 20s. The percentage of M shape in their 30s is elevated more than 10% compared to that in their 20s. The study of hairline shapes and 11 indexes of hairlines can be useful for planning of the hair transplantation and postoperative evaluation. This study being based on photogrammetry, there may be differences between actual distance of curved face and projected distance on flat photographs.