• 한국가축번식학회지
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• 제13권1호
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• pp.18-25
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• 1989

This study was carried out to investigate the general semen characteristics of the Korean native goat and the effect of temperature, incubation time, dilution rate, freezing rate and glycerol concentration on motility and NAR (normal apical ridge) acrosome of fresh and frozen Korean native goat spermatozoa. 1. Average semen volume per ejaculate, motility, concentration and pH of fresh Korean native goat spermatozoa were 0.19${\pm}$0.09 ml, 94.5${\pm}$0.47%, 26.17${\times}$108${\pm}$1.68/ml and 6.63${\pm}$0.18, respectively. 2. Motility and NAR acrosome of fresh spermatozoa during incubation were higher at 22$^{\circ}C$ than at 5$^{\circ}C$ or 37$^{\circ}C$(P<.01). 3. Motility and NAR acrosome of spermatozoa diluted 1:4 during incubation were higher at 22$^{\circ}C$ than at 5$^{\circ}C$ or 37$^{\circ}C$(P<.01). 4. Motility and NAR acrosome of spermatozoa during incubation were higher for samples diluted 1:1, 1:2, or 1:4 than for samples diluted 1:6(P<.01). 5. Motility and NAR acrosome of post-thaw spermatozoa were higher at freezing rate of 12$^{\circ}C$/min than at freezing rate of 1$^{\circ}C$/min or 24$^{\circ}C$/min when glycerol concentration was 9%(P<.01).

• The Korean Journal of Physiology and Pharmacology
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• 제4권4호
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• pp.333-338
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• 2000

We have examined whether bile acids can affect the electrical and mechanical activities of circular smooth muscle of canine colon and ileum, using isometric tension measurement or patch clamp technique. It was found that a dilution of canine bile $(0.03{\sim}2%\;by\;volume)$ enhanced or inhibited the amplitude of spontaneous contractions. An individual component of bile, deoxycholic acid (DCA) enhanced the frequency and amplitude of the spontaneous contractile activity at $10^{-6}\;M,$ while DCA at $10^{-4}\;M$ inhibited the contraction. Similarly, the response to cholic acid was excitatory at $10^{-5}\;M$ and inhibitory at $3{\times}10^{-4}\;M.$ Taurocholic acid at $10^{-4}\;M$ enhanced the amplitude of muscle contraction. Electrically, canine bile at 1% reversibly depolarized the colonic myocytes under current clamp mode. Bile acids also elicited non-selective cation currents under voltage clamp studies, where $K^+$ currents were blocked and the $Cl^-$ gradient was adjusted so that $E_{Cl}^-$ was equal to -70 mV, a holding potential. The non-selective cation current might explain the depolarization caused by bile acids in intact muscles. Furthermore, the bile acid regulation of electrical and mechanical activities of intestinal smooth muscle may explain some of the pathophysiological conditions accompanying defects in bile reabsorption.

• 대한기계학회논문집A
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• 제32권12호
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• pp.1115-1122
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• 2008

This paper presents a new microchip which can separate motile sperm by chemotaxis. The microchip was developed to create longitudinal concentration gradient in the microchannel due to diffusion. Linearly good concentration gradient of chemoattractant was generated without any fluid control devices. In sperm separation experiment with the developed microchip, mouse sperm was used as sample and acetylcholine was selected as chemoattractant. Human tubal fluid (HTF), buffer solution, was introduced into the microchannel of the microchip and attractants diluted in ratio of 1, 1/2, 1/4, 1/8, 1/16, 1/32 and 1/64 including control (DI water) were dropped in each outlet by $2\;{\mu}l$ volume with micropippet. After 5min, $1\;{\mu}l$ sperm solution was dropped into inlet of the chip. After 10 min, when sperms reached to the outlet by chemotaxis, we counted sperms in each outlet by using microscopy. Consequently, we could separate progressive motile sperm with the new microchip. In the experiment, the most sperms were isolated at the outlet dropped with 1/16 diluted solution. The optimal concentration gradient to induce chemotaxis was about 0.625 mg/ml/mm.

• Asian-Australasian Journal of Animal Sciences
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• 제13권7호
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• pp.901-905
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• 2000

An experiment was conducted to investigate the effect of caffeine, cAMP and cattle seminal plasma on preservation of semen at ultra low temperature ($-196{^{\circ}C}$). Each semen sample was divided into four parts equal in volume and sperm concentration; three were treated with caffeine, or cAMP, or cattle seminal plasma (CSP) and the fourth was kept as control. Sperm motility, abnormal spermatozoa, live-dead count and acrosomal damage were studied at different stages of freeze preservation viz.; just after dilution, at $5{^{\circ}C}$, at glycerolisation, before freezing, just after freezing, 24 hours of storage, and one week of storage. Sperm motility (58.39, 61.33, 52.00 and 50.39 per cent), non-eosinophilic spermatozoa (72.55, 69.98, 63.31 and 67.64 per cent), abnormal spermatozoa (5.71, 4.98, 8.04 and 5.66 per cent) and acrosomal damage (13.28, 13.33, 14.80 and 14.65 per cent) were observed in cAMP, caffeine, cattle seminal plasma and control, respectively, at every stage of freeze preservation. From this study it could be concluded that freezability of buffalo semen can be improved through the addition of caffeine followed by cAMP and cattle seminal plasma.

• 공업화학
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• 제25권2호
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• pp.147-151
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• 2014

많은 고분자 공정에서 고분자에서의 유기 용매와 같은 저분자 물질의 확산은 중요하다. 고분자에서의 저분자 물질의 이동은 중합 반응기의 효율성과 제조된 고분자의 특성을 결정한다. 공정을 설계하고 최적화하는데 중요한 물성값은 고분자/용매 상호확산 계수이다. 용매의 농도가 매우 낮은 무한희석 상태에서의 고분자/용매 계의 무한확산계수를 측정하기 위해서 capillary column inverse gas chromatography (CCIGC) 기법이 흔히 사용된다. 이 기법을 사용하면 비교적 짧은 시간에 확산계수와 분배계수를 측정하는 것이 가능하다. 본 연구에서는 CCIGC 기법을 사용해서 styrene/butadiene/styrene (SBS) 블록 공중합체에서 환형 구조를 가지는 용매의 확산계수와 분배계수를 다양한 온도 범위에서 측정하였다.

• 대한수의학회지
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• 제36권1호
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• pp.65-74
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• 1996

Atrial Natriuretic Peptide(ANP) is a hormone with potent natriuretic, diuretic and relaxing properties of vascular smooth muscle. Specific chemical modulator responsible for the ANP secretion has not yet been found. Although atrial stretch of stretch-release is to be a major stimulus for the secretion of ANP, the precise mechano-molecular transduction mechanism responsible for its evoked secretion remains to be elucidated. It is interested to clarify the effect of superoxide anion in the stretch-induced ANP secretion. In order to investigate the effectg of $H_2O_2$ in the regulation of ANP secretion, a perfused model of left atrium of rats was used. The results obtained were as follows; 1. The ANP secretion and the extracellular fluid(ECF) translocation were accentuated by the effect of repetitive atrial distension-reduction volume at atrial pressure($4cmH_2O$). 2. The dilution curve showed to be in parallel between pure atriopeptin III (AP III) and perfusated buffer. 3. $H_2O_2(5{\times}10^{-4}M)$ accenturated a strectch-release induced increase of the ANP secretion. The amount of released ANP was significantly(p<0.01) increased. These results suggest that the superoxide anion may be involved in the regulatory mechanism of mechanically activated ANP release.

• 한국미생물·생명공학회지
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• 제22권2호
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• pp.197-202
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• 1994

Microalga, Spirulina platensis has been cultivated in a pilot scale photo-bioreactor to treat wastewater and to produce high protein feedstocks from swine waste containing medium. 0.31(1/day) of specific growth rate and 0.170 of bioenergeric yield were obtanined from batch cultivation in 30% waster containing medium, compared to 0.71(1/day) and 0.545 from clean culture. An optimal dilution concentration was decided as 20% of working volume, based upon the cell growth and biomass productivity. The removal rate of nitrates in the wastewater was decreased as the adding concentration of wastewater was increased while the decrease of total phosphates was reversed, showing 0.33(1/day) and 0.30(1/day) of rate constants for nitrate removal in 10% addition and for phosphate removal in 30% addition, respectively. The chemical composition and amino acid profile of the biomass were superior to those of commerically available health food product, Spirulina sp.

• Asian Journal of Atmospheric Environment
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• 제1권1호
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• pp.1-8
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• 2007

Vehicle exhaust is a dominant source of air pollutants in urban areas. Since people are easily exposed to vehicle exhaust particles while driving a car and/or traveling via public transportation, air pollution near traffic has been extensively studied in developed countries. In this paper, investigations on vehicle-related fine particulate air pollution at roadsides and on roads in Seoul, Korea were reviewed to understand air pollution near traffic. Comparison of $PM_{10}$ concentrations in Seoul showed that roadside air is more contaminated than urban air, implying that exposure levels near vehicular emissions are more critical to sensitive persons. Concentrations of ultrafine particles and BC (black carbon) at roadsides of Seoul fluctuate highly for short durations, responding to traffic situations. Diurnal variations of ultrafine particles and BC concentrations at roadsides seem to be affected by traffic volume, mixing layer height, and wind speed. Concentrations of ultrafine particles and BC decrease as distance from the road increases due to dilution during transport. On-road air pollution seems to be more severe than roadside air pollution in Seoul. Since nearby traffic air pollution has not been well understood in Seoul, further studies including various vehicular air pollutants and representative locations are needed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1763-1765
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• 2000

This paper presents deposition and characterizations of microcrystalline silicon ($\mu$ c-Si:H) films prepared by hot wire chemical vapor deposition at substrate temperature at 300$^{\circ}C$. The flow rates of $SiH_4$ gas are critical parameter for the formation of Si films with microcrystalline phase. We could obtain $\mu$ c-Si:H with columnar grain structure and volume fraction of 75% without H2 dilution. The electronic properties, hydrogen bonding configurations, and $H_2$ concentration inside the films are also strongly affected by $SiH_4$ flow rate, which is provided in this paper.

• Food Science and Biotechnology
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• 제15권4호
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• pp.572-577
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• 2006

The physiochemical interactions of 1-methylcyclopropene (1-MCP) and adsorbing agents can be described using a very powerful tool, inverse gas chromatography (IGC). Sorption behavior of 1-MCP on various adsorbing agents was assessed using the profile peaks of 1-MCP at an infinite dilution concentration using the IGC technique. Chromatogram peaks of 1-MCP adsorption were not observed for the adsorbing agent activated carbon. The forms of sorption isotherms followed Henry's law, and behaved according to the binding site theory. Specific retention volume and distribution coefficients for 1-MCP on the adsorbing agents were determined at 50, 60, 70, and $80^{\circ}C$, respectively. Silica gel had a much higher number of binding sites for 1-MCP compared to Tenax-TA and activated clay agents. Meanwhile, activated carbon proved to be a very strong binding agent for 1-MCP based on 1-MCP efficiency experiments on the selected adsorbing agents. However, as a proper means of delivering 1-MCP molecules to fresh food products, activated carbon is not fit for the binding and release of 1-MCP gas under dry or high humidity conditions because activated carbon has a strong affinity for 1-MCP, even when treated with distilled water.