• Korean Journal of Radiology
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• v.21 no.11
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• pp.1199-1209
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• 2020

The glymphatic system hypothesis is a concept describing the clearance of waste products from the brain. The term "glymphatic system" combines the glial and lymphatic systems and is typically described as follows. The perivascular space functions as a conduit that drains cerebrospinal fluid (CSF) into the brain parenchyma. CSF guided to the perivascular space around the arteries enters the interstitium of brain tissue via aquaporin-4 water channels to clear waste proteins into the perivascular space around the veins before being drained from the brain. In this review, we introduce the glymphatic system hypothesis and its association with fluid dynamics, sleep, and disease. We also discuss imaging methods to evaluate the glymphatic system.

• Near Infrared Analysis
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• v.2 no.1
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• pp.43-53
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• 2001

A non-invasive spectroscopic method is presented for the measurement of pulmonary edema. Both early diagnosis and quantitative edema estimates were investigated. The spectroscopic determination of pulmonary edema involved the acquisition of diffuse reflectance spectra in the near-infrared (NIR) region with change in water concentration - water is the main constituent of edema fluid. Pulmonary edema was induced into the excised perfused lungs of seven animals by elevating the hydrostatic pressure. Estimates of edema were ascertained from a partial least squares regression of the measured spectral response. Actual edema was determined from the change (increase) in total lung weight. Estimates in relative lung weight increases due to in vitro edema were made with the near infrared spectra. The results revealed that fluid accumulation produced spectral changes in the O-H and C-H absorptions as well as scattering changes in the spectra. Histology of the lung was used to verify the presence or absence of interstitial and alveolar edema. Results demonstrated that near infrared spectroscopy might provide a new tool for clinical assessment of pulmonary edema.

• Transactions of the Korean hydrogen and new energy society
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• v.2 no.1
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• pp.47-56
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• 1990

Pure titanium rods were oxidized by anodic oxidation, furnace oxidation and flame oxidation and used as a electrode in the photodecomposition of water. The maximum photoelectrochemical conversion efficiency(${\eta}$) was found for flame oxidized electrode ($1200^{\circ}C$ for 2 min in air), 0.8 %. Anodically oxidized electrodes have minimum photoelectrochemical conversion efficiencies, 0.3 %. Furnace oxidized electrode ($800^{\circ}C$ for 10min in air) has 0.5% phtoelectrochemical efficiency and shows a band-gap energy of about 2.9eV. The efficiency shows a parallelism with the presence of the metallic interstitial compound $TiO_{O+X}$(X < 0.33) at the metal-semiconductor interface, the thickness of the sub oxide layer and that of the external rutile scale.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.258-267
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• 2003

Recently inside nano liposome particles or nano-emulsions which contain tough-melting physiology activity materials or the coefficient of low organism utilization promote the coefficient of organism utilization, so this part has been studied a lot because they can absorb selectly cosmetics, specially physiology activity materials, into the skin. Also, in particle size, cells interstitial lipid interval are 30~50nm, so nano-emulsions that the size is similar to 30~50 nm are made to study for absorbing quickly into the skin. And transparent skin which contains oils in common skin lotion dosage form has become the center of public interest. The used nano-emulsions in this study were unsaturated lecithin/co-surfactant! ethanol/ oil / water. And polysorbate 20/ polysorbate 80/ Dicetyl phosphate/hydrogenated .caster oil/ isoceteth-20/SLS were used in co-surfactant. The used oils were cyclomethicone and caprylic/capric triglyceride. The manufacturing process was that microfluidizer was fixed in 1000bar and transit times were changed from 1 to 10 times. From transparency and particle size, the transparency sequence was SLS> polysorbate 20= polysorbate 80> isoceteth-20> dicetyl phosphate >hydrogenated caster oil and the particle size was small. Specially cyclomethicone nano-emulsions, when we made unsaturated lecithin /SLS /ethanol/water/cyclomethicone, cyclomethicone 5％ was good for transparency. And 20％ of this was used for making transparent skin toner in common skin dosage form.

• Korean Journal of Veterinary Research
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• v.16 no.2
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• pp.187-190
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• 1976

In order to approximate plasma volume, extracellular fluid volume and total body water volume of Korean native goats, measurements were made of the volumes of distribution of Evans blue, potasium thiocyanate and antipyrine. The results obtained in this work were summarized as follows: 1. Plasma volume showed a range of 50 to 72ml/kg with a mean of $62{\pm}6.2ml/kg$ (SD). 2. Blood volume showed a range of 69 to 98ml/kg with a mean of $85{\pm}7.9ml/kg$. 3. Extracellular fluid volume showed a range of 265 to 310ml/kg with a mean of $297{\pm}18.3ml/kg$. 4. Interstitial fluid volume showed a range of 204 to 261ml/kg with a mean of $236{\pm}16.8ml/kg$. 5. Intracellular fluid volume showed a range of 380 to 436ml/kg with a mean of $420{\pm}12.6ml/kg$. 6. The volume of total body water showed a range of 680 to 735ml/kg with a mean of $714{\pm}17.7ml/kg$.

• Journal of Environmental Impact Assessment
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• v.7 no.2
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• pp.5-14
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• 1998

This study was performed to estimate interrelation between characteristics of sediment and nutrient releare from sediment in Dae-cheong lake. For the investigations, sediments were sampled in June and October 1997 at fish farms, embayment, and the main stream of Dae-cheong lake. Items for investigation are as follows; water content, weight loss on ignition(IG), porosity of sediment, Total Kjeldahl Nitrogen(TKN), content of element(H, N, C), nutrient release rate. Water content and porosity were measured to conjecture the physical trait and grain size. And weight loss on ignition was measured to determine the contents of organic substance. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentration of interstitial water and overlying water were measured. Release rate of nutrients which has direct influenced upon the water quality were 0.05-8.63mg-$P/m^2{\cdot}day$ and 4.99-36.56mg-$N/m^2{\cdot}day$. And it was found that release rate was measured higher in the 1st sampling than in the 2nd sampling. And for determination of the humus level of sediment, carbon and nitrogen content were measured by using elemental analyzer. Generally, C/N ratio is used to determine humus level of lake sediment. As a result of elemental analysis, C/N ratio was determined in the range of 7.64~11.55, so humus level of Dae-cheong lake sediment was estimated from mesohumic state to oligohumic state.

• Journal of the Korean Electrochemical Society
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• v.22 no.1
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• pp.13-21
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• 2019

Prussian blue analogues(PBAs) are comprised of cyano-bridged transition metal ions. The wide and unique open-framework structures of the PBAs enable reversible intercalation and deintercalation of various ions such as $Na^+$, $K^+$, $Mg^{2+}$, $Zn^{2+}$, etc. In addition, since PBAs are synthesized through coprecipitation reaction in aqueous solution at room temperature, they are produced economically and environmentally friendly. However, the formation of crystals proceeds rapidly, and defects such as vacancy and crystal water tend to be present in the crystals, thereby affecting key battery performance. Therefore, significant efforts to inhibit defects in PBAs have been made. In the case of vacancy, the reaction rate was controlled at the synthesis stage to reduce the formation of vacancy, and the crystal water was removed by heat treatment under vacuum. In addition, by adding transition metals that do not react within the structure of PBA, the structural instability during the electrochemical reaction was largely alleviated.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.295-300
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• 2007

A new characterization method using a porous plug model was proposed to determine the degree of sulfonation (DS) of ionomer binder with respect to the membrane used in membrane-electrode assemblies (MEAs) and to analyze the fraction of proton pathways through ionomer-catalyst combined electrodes in MEAs for polymer electrolyte fuel cells (PEFCs). Sulfonated poly(ether ether ketone) was prepared to use a polymeric electrolyte and laboratory-made SPEEK solution (5wt.%, DMAc based) was added to catalyst slurry to form catalyst layers. In case of the SPEEK-based MEAs in this study, DS of ionomer binder for catalyst layers should be the same or higher than that of the SPEEK membrane used in the MEAs. The porous plug model suggested that most of protons were via the ionomer binder (${\sim}92.5%$) bridging the catalyst surface to the polymeric electrolyte, compared with the pathways through the alternative between the interstitial water on the surface of ionomer binder or catalyst and the ionomer binder (${\sim}7.3%$) and through only the interstitial water on the surface of ionomer or catalyst (${\sim}0.2%$) in the electrode of the MEA comprising of the sulfonated poly(ether ether ketone) membrane and the 5wt.% SPEEK ionomer binder. As a result, it was believed that the majority of proton at both electrodeds moves through ionomer binder until reaching to electrolyte membrane. The porous plug model of the electrodes of MEAs reemphasized the importance of well-optimized structure of ionomer binder and catalyst for fuel cells.

• The Journal of Engineering Geology
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• v.6 no.3
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• pp.155-163
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• 1996

The current ASTM C227-90 is a prescription on the mortar-bar method. This recornrnends that mortar-bars should be made using a mixing ratio by weight of 675 grams aggregate to 300 grams cement, and their initial lengths should be measured in $24{\pm}2$ hours. This method emphasizes that the prepare sample mortar-bars and calculate expansion rates of them. This method requires constant G values (effective gauge lengths) of denominator in the calculation formula, which are fixed either at 10 inches or 250mm. This study, based on experimental approaches, reexamines the suggestions made by those two prescriptions above and important results are summarized in the following. 1. Not only alkali-aggregate reaction but also interaction of interstitial and gel water are responsible for expansion of mortar-bars. This requires partial modification of the current ASTM C227-90. 2. A mixing ratio by volume rather than by weight of aggregate to cement is recommendable for measuring the amount of expansion resulting from alkali-aggregate reaction and from interstitial water. 3. The method of when to measure initial lengths and how to calculate expansion rate suggested by ASThI C227-90 and Cl90-93a should partly be modified for more accurate results.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.2
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• pp.133-144
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• 2000

Objective: Several water channels (aquaporins; AQP) that belong to the MIP (major intrinsic protein) family have identified. In the selected tissues including red blood cells or renal tubules, water movements are abundant and/or physiologically important. Unexpectedly, a high water permeability of human and ram sperm has been reported. Recent studies showed that AQP7 and AQP8 are present in testes, so that the high water permeability of human sperm suggested to be mediated by AQPs. Method: To identify the identity of aquaporins expressed in testes, RT-PCR was performed using degenerative primers, which were designed to correspond to highly conserved sequences surrounding the Asn-Pro-Ala (NPA) motifs in the aquaporins. New expressed AQP series were reconfirmed by immunohistochemical study using rabbit polyclonal antibodies. Results: DNA sequencing of PCR products revealed that AQP2 and AQP3 mRNA as well as AQP7 and AQP8 are expressed in human and rat testes. In human and rat testes, AQP2 are expressed in spermatozoa, interstitial cells and myofibroblasts and AQP3 are expressed in myofibroblasts of semineferous tubules on immunocytochemical stain. Conclusion: These results indicate that multiple aquaporins are expressed in testes, and that they may have important roles in the spermatogenesis and the germ cell function of testis.