• Title/Summary/Keyword: Concentration profiles

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Effects of Cesarean Section in Dogs on Blood Coagulation Profiles (개 제왕절개 수술이 혈액응고계에 미치는 영향)

  • Ahn, So-Jeo;Jeoung, Seok-Young;Kwon, Eun-Jung;Park, Son-Il;Kim, Doo
    • Journal of Veterinary Clinics
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    • v.24 no.2
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    • pp.160-163
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    • 2007
  • Patients often present with spontaneous bleeding, or a bleeding disorder may be discovered when an otherwise healthy dog develops marked bleeding during or after surgery. In this study, we were aimed to elucidate whether the cesarean section in dogs has influence on the coagulation profiles. And we gained the normal data on a panel of screening laboratory tests which allow accurate characterization of a hemostatic defects in dogs. Of the 20 healthy adult dogs, buccal mucosa bleeding time (BMBT) was $83.0{\pm}10.5$ seconds, platelet count was $24.0{\pm}3.5{\times}10^4/{\mu}l$, activated partial thromboplastin time (APTT) was $8.8{\pm}2.0$ seconds, the concentration of fibrinogen was $288.5{\pm}77.9mg/dl$, and the concentration of fibrin degradation products (D-dimer) was <250.0 ng/ml. Coagulation profiles before and after cesarean section of 13 cesarean sectioned dogs were in the normal range and there were no statistical differences in coagulation profiles between normal dogs and cesarean sectioned dogs (p>0.05). The results suggested that labor and cesarean section in healthy dogs did not alter coagulation profiles.

Preparation and in Vitro Release of Melatonin-Loaded Multivalent Cationic Alginate Beads

  • Lee, Beom-Jin;Min, Geun-Hong;Kim, Tae-Wan
    • Archives of Pharmacal Research
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    • v.19 no.4
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    • pp.280-285
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    • 1996
  • The sustained release dosage form which delivers melatonin (MT) in a circadian fashion over 8 h is of clinical value for those who have disordered circadian rhythms because of its short halflife. The purpose of this study was to evaluate the gelling properties and release characteristics of alginate beads varying multivalent cationic species $(Al^{+++}, \; Ba^{++}, \; Ca^{++}, \; Mg^{++}, \; Fe^{+++}, \; Zn^{++})$. The surface morphologies of Ca- and Ba-alginate beads were also studied using scanning electron microscope (SEM). MT, an indole amide pineal hormone was used as a model drug. The $Ca^{++}, \; Ba^{++}, \; Zn^{++}, \; Al^{++}\; and\; Fe^{+++}\; ions\; except\; Mg^{++}$ induced gelling of sodium alginate. The strength of multivalent cationic alginate beads was as follows: $Al^{+++}\llFe^{+++} the induced hydrogel beads were very fragile and less spherical. Fe-alginate beads were also fragile but stronger compared to Al-alginate beads. Ba-alginate beads had a similar gelling strength but was less spherical when compared to Ca-alginate beads. Zn-alginate beads were weaker than Ca- and Ba-alginate beads. Very crude and rough crystals of Ba- and Ca-alginate beads at higher magnifications were observed. However, the type and shape of rough crystals of Ba- and Ca-alginate beads were quite different. No significant differences in release profiles from MT-loaded multivalent cationic alginate beads were observed in the gastric fluid. Most drugs were continuously released upto 80% for 5 h, mainly governed by the passive diffusion without swelling and disintegrating the alginate beads. In the intestinal fluid, there was a significant difference iq the release profiles of MT-loaded multivalent cationic alginate beads. The release rate of Ca-alginate beads was faster when compared to other multivalent cationic alginate beads and was completed for 3 h. Ba-alginate beads had a very long lag time (7 h) and then rapidly released thereafter. MT was continuously released from Feand Zn-alginate beads with initial burstout release. It is assumed that the different release rofiles of multivalent cationic alginate beads resulted from forces of swelling and disintegration of alginate beads in addition to passive diffusion, depending on types of multivalent ions, gelling strength and drug solubility. It was estimated that 0.2M $CaCl_2$ concentration was optimal in terms of trapping efficiency of MT and gelling strength of Ca-alginate beads. In the gastric fluid, Ca-alginate beads gelled at 0.2 M $CaCl_2$ concentration had higher bead strength, resulting in the most retarded release when compared to other concentrations. In the intestinal fluid, the decreased release of Ca-alginate beads prepared at 0.2 M $CaCl_2$ concentration was also observed. However, release profiles of Ca-alginate beads were quite similar regardless of $CaCl_2$ concentration. Either too low or high $CaCl_2$ concentrations may not be useful for gelling and curing of alginate beads. Optimal $CaCl_2$ concentrations must be decided in terms of trapping efficiency and release and profiles of drug followed by curing time and gelling strength of alginate beads.

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Thermal and Flow Analysis in a Proton Exchange Membrane Fuel Cell

  • Jung, Hye-Mi;Koo, Ja-Ye
    • Journal of Mechanical Science and Technology
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    • v.17 no.9
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    • pp.1358-1370
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    • 2003
  • The effects of anode, cathode, and cooling channels for a Proton Exchange Membrane Fuel Cell (PEMFC) on flow fields have been investigated numerically. Continuous open-faced fluid flow channels formed in the surface of the bipolar plates traverse the central area of the plate surface in a plurality of passes such as a serpentine manner. The pressure distributions and velocity profiles of the hydrogen, air and water channels on bipolar plates of the PEMFC are analyzed using a two-dimensional simulation. The conservation equations of mass, momentum, and energy in the three-dimensional flow solver are modified to include electro-chemical characteristics of the fuel cell. In our three-dimensional numerical simulations, the operation of electro-chemical in Membrane Electrolyte Assembly (MEA) is assumed to be steady-state, involving multi-species. Supplied gases are consumed by chemical reaction. The distributions of oxygen and hydrogen concentration with constant humidity are calculated. The concentration of hydrogen is the highest at the center region of the active area, while the concentration of oxygen is the highest at the inlet region. The flow and thermal profiles are evaluated to determine the flow patterns of gas supplied and cooling plates for an optimal fuel cell stack design.

Progesterone assays as an aid for improving reproductive efficiency in dairy cattle III. Milk progesterone profiles in repeat-breeder dairy cows (Progesterone 농도측정(濃度測定)에 의한 유우(乳牛)의 번식효율증진(繁殖效率增進)에 관한 연구(硏究) III. 저수태우(低受胎牛)에서 유즙(乳汁)중 progesterone 농도변화(濃度變化))

  • Kang, Byong-kyu;Choi, Han-sun;Choi, Sang-gong;Son, Chang-ho;Chon, Hong-suk
    • Korean Journal of Veterinary Research
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    • v.34 no.1
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    • pp.189-193
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    • 1994
  • This study was undertaken to clarify the relationship between the cause of repeat-breeder and the luteal dysfunction in repeat-breeder dairy cows that failed to conceive to three or more artificial insemination(AI) at a regular interval. Progesterone concentrations were measured in milk fat for 20 to 22 days after AI. From the 15 repeat-breeder dairy cows, six cows had a normal progesterone profiles. Five cows showed a delayed rise of the progesterone concentrations until 7 to 10 days after AI, two cows had a comparatively low concentration of milk progesterone below 150 ng/ml through most of the luteal phase, and two cows had a combined pattern of a delayed rise and a low concentration of milk progesterone during luteal phase. It is suggest that luteal dysfunction as indicated by progesterone profiles is one of the causes of repeat-breeder in dairy cows.

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Photoisomerization of Symmetric Carbocyanines

  • 민형식;강유남;박정희
    • Bulletin of the Korean Chemical Society
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    • v.19 no.7
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    • pp.747-753
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    • 1998
  • The phoisomerization process of symmetric carbocyanine dyes such as 3,3'-diethyloxadicarbocyanine iodide (DODCI), 3,3'-diethylthiadicarbocyanine iodide (DfDCI), 1,1'-diethyl-2,2'-dicarbocyanine iodide (DDI), 1,1'-diethyl-2,2'-carbocyanine iodide (DCI), and cryptocyanine (1,1'-diethyl-4,4'-carbocyanine) iodide (CCI) have been studied by measuring the steady state and time resolved fluorescence spectra and the ground-state recovery profiles. The steady-state fluorescence spectrum of photoisomer as a function of concentration and excitation wavelength provides the evidence that the fluorescence of photoisomer is formed by the radiative energy transfer from the normal form and the quantum yield for the formation of photoisomer is increased by decreasing the excitation wavelength. The fluorescence decay profiles have been measured by using the time correlated single photon counting (TCSPC) technique, showing a strong dependence on the concentration and the detection wavelength, which is due to the formation of excited photoisomers produced either by the radiative energy transfer from the non-nal form or by absorbing the 590 nm laser pulse. We first report the fluorescence decay time of photoisomers for these cyanine dyes. The experimental results are explained by introducing the semiempirical calculations. The ground state recovery profiles of DTDCI, DDI, and CCI normal forms have been measured, showing that the recovery time from the singlet excited state is similar with the fluorescence decay time.

Investigation of Vertical Profiles of Meteorological Parameters and Ozone Concentration in the Mexico City Metropolitan Area

  • Benitez-Garcia, Sandy E.;Kanda, Isao;Okazaki, Yukiyo;Wakamatsu, Shinji;Basaldud, Roberto;Horikoshi, Nobuji;Ortinez, Jose A.;Ramos-Benitez, Victor R.;Cardenas, Beatriz
    • Asian Journal of Atmospheric Environment
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    • v.9 no.2
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    • pp.114-127
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    • 2015
  • In the Mexico City Metropolitan Area (MCMA), ozone ($O_3$) concentration is still higher than in other urban areas in developed countries. In order to reveal the current state of photochemical air pollution and to provide data for validation of chemical transport models, vertical profiles of meteorological parameters and ozone concentrations were measured by ozonesonde in two field campaigns: the first one, during the change of season from wet to dry-cold (November 2011) and the second during the dry-warm season (March 2012). Unlike previous similar field campaigns, ozonesonde was launched twice daily. The observation data were used to analyze the production and distribution of ozone in the convective boundary layer. The observation days covered a wide range of meteorological conditions, and various profiles were obtained. The evolution of the mixing layer (ML) height was analyzed, revealing that ML evolution was faster during daytime in March 2012 than in November 2011. On a day in November 2011, the early-morning strong wind and the resulting vertical mixing was observed to have brought the high-ozone-concentration air-mass to the ground and caused relatively high surface ozone concentration in the morning. The amount of produced ozone in the MCMA was estimated by taking the difference between the two profiles on each day. In addition to the well-known positive correlation between daily maximum temperature and ozone production, effect of the ML height and wind stagnation was identified for a day in March 2012 when the maximum ground-level ozone concentration was observed during the two field campaigns. The relatively low ventilation coefficient in the morning and the relatively high value in the afternoon on this day implied efficient accumulation of the $O_3$ precursors and rapid production of $O_3$ in the ML.

Batch Variation and Pharmacokinetics of Oral Sustained Release Melatonin-loaded Sugar Spheres in Human Subjects

  • Lee, Beom-Jin;Ryu, Seung-Goo;Choi, Han-Gon;Kim, Chong-Kook;Parrott, Keith-A.;Ayres, James-W.;Sack, Robert-L.
    • Archives of Pharmacal Research
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    • v.20 no.6
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    • pp.555-559
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    • 1997
  • The three different batches of an oral sustained release melatonin (MT) delivery system were prepared by aqueous-based fluid-bed coating of the sugar spheres for the evaluation of in vitro release characteristics and plasma concentration profiles in human subjects. The MT contents in 20% coated sugar spheres of three batches (B1, B2 and B3) were $3.3{\pm}0.08$, $2.4{\pm}0.1$ and $2.5{\pm}0.13$ mg per gram of coated sugar spheres, respectively. The release profiles of three different batches had a very similar fashion. However, the release profiles of three different batches had a very similar fashion. However, the release half-lives $(T_{50%})$ of MT from B1, B2 and B3 was $3.70{\pm}0.2$, $5.2{\pm}0.2$ and $4.9{\pm}0.07h$, respectively. Plasma concentration profiles of sustained release 0.2mg melatonin-loaded sugar spheres containing 10% immediate release melatonin in gelatin capsules (B1 and B2) were then evaluated in human subjects. The in vivo plasma concentration profies of the two batches (B1 and B2) were very similar each other and located between the physiological endogenous ranges. The time to reach the peak concentration $(T_max)$ was more advanced in case of B1 when compared to B2. However, there was no statistically significant difference in the maximum concentration $(C_max)$ and the area under the curve (AUC) between B1 and B2. The AUC of melatonin-loaded sugar spheres containing 10% and 20% immediate release MT in human subjects had a good linearity between dose and AUC, regardless of the fraction of immediate release MT, indicating the first order elimination process of MT within these doses. The current oral sustained release MT delivery system may be utilized to treat circadian rhythm disorders if it is proven to be more clinically useful when compared to immediate release MT.

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Ozone Monitoring in the Lower Tropospheric Atmosphere by LIDAR System (라이다 시스템을 이용한 하층 대류권 오존농도 측정)

  • 최성철;차형기;김덕현;김영상
    • Journal of Korean Society for Atmospheric Environment
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    • v.17 no.5
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    • pp.385-393
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    • 2001
  • We have developed a Differential Absortion LIDAR (DIAL) method for the measurement of lower tropospheric ozone concentration. We used two laser beams from quadrupled Nd:YAG (266 nm) for the resonance wavelength and dye lasers (299.5 nm) for non -resonance wavelength. Aerosol extinction coefficients in the lower troposphere was computed by both Klett and Slope methods. To correct the SIN (Signal -Induced Noise) effect caused by photo detector, we subtracted a new-fitted baseline on the background part of a LIDAR signal, after the subtraction of the DC level. This is because SIN can be treated as an exponentially decaying tail. Using theme results, ozone profiles were obtained approximately 2km at daytime and 3km at nighttime. We compared the results derided by the Slope method with those measured by UV spectrometer. The computed results are in mostly good agreement with experimental results. In the measurement of the vertical layer, we observed the variation of the ozone profiles around the top mixed layer.

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Development of Novel Techniques for Determining the Oxygen Tracer Diffusion Coefficients in Oxides II - Measurements of the Depth Profiles of $^{18}O$ Concentration in the solid Samples by Raman Spectroscopy (산화물에서의 산소추적자확산계수를 결정하는 새로운 방법의 개발 II - 라만분광법에 의한 고체시료 중의 시간에 따른 $^{18}O$ 농도변화 측정 -)

  • 김병국;마하구찌히로오;박순자
    • Journal of the Korean Ceramic Society
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    • v.31 no.12
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    • pp.1459-1466
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    • 1994
  • A novel technique for determining the oxygen tracer diffusion coefficients in oxides was developed. After the 16O-18O solid-gas exchange reactions between 16O in the oxides and 18O in the ambient gas, Raman spectra of the cross sections of oxide samples were measured in a spatial resolution of 5 ${\mu}{\textrm}{m}$. From thus obtained Raman spectra, depth profiles of 18O concentration in the oxide samples were calculated. The oxygen tracer diffusion coefficients and the surface exchange coefficients were determined under the assumptions that samples are semi-infinite slab and that the surface exchange reactionsare not negligible. The oxygen tracer diffusion coefficient of 2.8 mol% Y2O3-containing tetragonal ZrO2 polycrystals, 8 mol% Y2O3-containing ZrO2 polycrystals, and 10 mol% Y2O3-containing cubic ZrO2 single crystals (along the a axis) are as follows.

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