Search

The quality control of testing and inspection laboratories operated in Korea, the United States, and Canada was compared. The basic framework of on-site evaluation operated by each country was similar in terms of evaluation procedure, document evaluation, issuance of verification certificate, and follow-up management. For conducting on-site evaluation and granting the certificate, the preparation materials and evaluation processes are subdivided in Korea, while the dates of granting the certificate are restricted to four times a year in the United States. After receiving accreditation as a testing/inspection laboratories for the first time in Canada, follow-up management is divided into re-evaluation, verification evaluation, and monitoring evaluation.

The concept of physiological link between the gut and the skin, known as the gut-skin axis, has been gaining more evidence recently. Although experimental data from animal and human studies support the existence of the gut-skin axis, in vitro model platforms that can test the hypothesis are lacking. Organ-on-a-chip offers the possibility of connecting different tissues and recapitulating interactions between them. In this study, we report a multiorgan chip that can capture the basic interorgan communication between the gut and the skin. Its modular design enables separate culture and differentiation of the gut and skin tissues, and after assembly the two organs are connected via microfluidic channels than enables perfusion and mass transfer. We showed that the impairment of the gut barrier function exacerbated the adverse effect of fatty acids on skin cells, with decreased viability, increased level of cytokine secretion and human beta defensin-2 (hBD-2), an inflammatory dermal disease marker. Based on these results, we believe that our multiorgan chip can be a novel in vitro platform for recapitulating complex mechanisms underlying the gut-skin axis.

The importance of physiologically realistic in vitro skin models in development of cosmetics and drugs for skin disorders have been well recognized, but current in vitro skin models carry several limitations in recapitulating the physiology of the human skin. Recently, in vitro skin models in a microfluidic platform have been proposed with improved physiological relevance. Survival and differentiation of skin tissue construct requires accurate refinement of cell culture environment, which can be different for static and dynamic culture conditions. In this study, we studied the effect of different culture conditions on the skin construct in a microfluidic skin chip. Our observation suggests that different seeding cell concentrations, thickness of the collagen matrix, volume of cell culture media and the frequency of media exchange affects the cell viability, extent of collagen gel contraction, and adherence of keratinocytes to the gel matrix. Our study provides valuable information about optimization of cell culture conditions in a microfluidic skin chip.

This study validates the relationship between the perceived brands of Korean wave and country-of-origin image (COI) of Korea on the basis of categorization and stereotype content theories. Data col...

The forced cultivation of strawberries (Fragaria &times, ananassa Duch.) requires fast flower bud differentiation. Using temporary nutrient-withholding periods is a common management practice for inducing flower bud differentiation at strawberry nurseries in the Republic of Korea. After the temporary nutrient-withholding period, nutrient solution resupply can advance both flower bud growth and fruit yield. This study aims to determine the optimal nutrient solution resupply period with anatomical analysis in order to find a method for fast flower bud differentiation in the early harvest period. Here, the runner plants were divided into 5 groups, each receiving a treatment period of watering (W) and nutrient solution (N) (W40 + N0 (control), W30 + N10, W20 + N20, W10 + N30, and W0 + N40, each number represents the days of the treatment period). The nutrient solution treatments were supplied using a strawberry nutrient solution developed by Gyeongsangnam-do Agricultural Research and Extension. Rapid flower bud differentiation was found for W20 + N20 via anatomical analysis. When the temporary nutrient-withholding period was decreased, the T-N (total nitrogen), P, K, and S concentrations showed a tendency to increase. The C/N ratio showed a tendency to decrease when the nutrient solution resupply period was increased. The W20 + N20 group showed faster flower bud development than the other groups at 10 days before transplanting and on the day of transplanting (2.2 and 5.5), 6 days in a primary cluster budding ratio, and 16 days in flowering plants. No differences in fruit characteristics were observed for the different treatments. In conclusion, the W20 + N20 treatment, which maintains fast flowering, seems to be appropriate for nutrient solution resupply treatment for &ldquo, Maehyang&rdquo, strawberries during the nursery period.

We investigated the effects of red and blue light on the growth and content of bioactive compounds of Salvia plebeia R. Br in a closed-type plant production system (CPPS). The seedlings of Salvia plebeia R. Br. were transplanted into a deep floating technique system with nutrient recycling (pH 6.5 and electrical conductivity (EC) 1.5 dS∙m&minus, 1). The plants were cultured for a duration of 35 days at 25 &plusmn, 1 &deg, C, with relative humidity 60 &plusmn, 5%, a 12/12 h (light/dark) photoperiod, and a light intensity of 180 &micro, mol∙m&minus, 2∙s&minus, 1 photosynthetic flux photon density, providing standard fluorescent (FL) lighting and various light qualities of red:blue ratios (10:0, 7:3, 5:5, 3:7, and 0:10) in the CPPS. The growth characteristics of Salvia plebeia R. Br., such as leaf length, leaf area, and fresh and dry weights of shoots, were the greatest in Red only and R7B3. The leaf shape index was the highest in Blue only and specific leaf weight was lower in FL and Blue than in the other treatments. The photosynthetic rate was the highest in R7B3. The total phenolic and flavonoid concentrations per gram of fresh weight of Salvia plebeia R. Br. were higher in combined light, such as R7B3, R5B5, and B3B7, than in the monochromatic light treatments. However, the antioxidant activity per fresh weight was the highest in FL. In conclusion, the results suggest that 7:3 is the most effective red and blue light ratio for production of high quality Salvia plebeia R. Br. in a CPPS.

Adenophora triphylla var. japonica Hara is a highly valued medicinal plant that is used to treat or prevent bronchitis, cough, cancer, and obesity. However, there has been no study on the production of Adenophora triphylla var. japonica Hara seedlings in a closed-type plant production system (CPPS). This study was conducted to examine the growth characteristics of Adenophora triphylla var. japonica Hara seedlings as affected by different growing media. The seeds were sown on a 128-cell plug tray filled with urethane sponges (US), LC grow foam (LC), rockwool (RW), or terra-plugs (TP). The seedlings were cultured for a duration of 54 days under temperature 25 &plusmn, 1&deg, C, a photoperiod of 12/12 h (light/dark), and light intensity of 180 &micro, mol&middot, m&minus, 2&middot, s&minus, 1 photosynthetic photon flux density provided by RB LEDs (red:blue = 8:2) in a closed-type plant production system (CPPS). The germination rate of Adenophora triphylla var. japonica Hara was significantly highest in the TP. Also, seedling shoot growth indicators of plant height, leaf length, leaf width, number of leaves, fresh weight (FW), and dry weight (DW) of the shoot, and leaf area were markedly the greatest in the TP and the lowest in the US. The SPAD (soil-plant analysis development) value was higher in the TP and US than in the LC or RW. In addition, the seedling root growth characteristics of total root length, root surface area, root volume, and number of root tips were significantly greatest in the TP. Moreover, the maximum root diameter, FW and DW of roots were the greatest in the TP. In conclusion, the results suggest that TP are viable for the growth development of Adenophora triphylla var. japonica Hara seedlings.

Adenophora triphylla var. japonica Hara is a highly valued medicinal plant that is used to treat or prevent bronchitis, cough, cancer, and obesity. However, there has been no study on the production of Adenophora triphylla var. japonica Hara seedlings in a closed-type plant production system (CPPS). This study was conducted to examine the growth characteristics of Adenophora triphylla var. japonica Hara seedlings as affected by different growing media. The seeds were sown on a 128-cell plug tray filled with urethane sponges (US), LC grow foam (LC), rockwool (RW), or terra-plugs (TP). The seedlings were cultured for a duration of 54 days under temperature 25 ± 1°C, a photoperiod of 12/12 h (light/dark), and light intensity of 180 µmol·m−2·s−1 photosynthetic photon flux density provided by RB LEDs (red:blue = 8:2) in a closed-type plant production system (CPPS). The germination rate of Adenophora triphylla var. japonica Hara was significantly highest in the TP. Also, seedling shoot growth indicators of plant height, leaf length, leaf width, number of leaves, fresh weight (FW), and dry weight (DW) of the shoot, and leaf area were markedly the greatest in the TP and the lowest in the US. The SPAD (soil-plant analysis development) value was higher in the TP and US than in the LC or RW. In addition, the seedling root growth characteristics of total root length, root surface area, root volume, and number of root tips were significantly greatest in the TP. Moreover, the maximum root diameter, FW and DW of roots were the greatest in the TP. In conclusion, the results suggest that TP are viable for the growth development of Adenophora triphylla var. japonica Hara seedlings.

휴대용 고분자전해질 연료전지의 수소발생용으로써 NaBH4는 많은 장점을 갖고 있다. 본 연구에서는 고농도 NaBH4용액에서 비담지 Co-P-B, Co-B 촉매의 NaBH4 가수분해 특성에 대해 연구하였다. 고농도에서 수소 발생 수율을 높이기 위해 NaBH4 가수분해 반응의 수소 발생 수율에 미치는 촉매 형태, NaBH4 농도, 응축수 회수 등의 영향에 대해 실험하였다. Co-P-B 제조과정에서 붕소의 비가 높아질수록 수소 발생 수율이 증가하였다. Co-P:B = 1:5 촉매를 사용해 NaBH4 수용액 농도를 20 wt%에서 25 wt%로 증가시켰을 때 수소 발생 수율이 감소하였다. Co-P-B와 Co-B 촉매를 같이 사용한 반응기에서 촉매 팩의 두께를 감소시키고 응축수를 회수하여, NaBH4 25 wt% 수용액으로 최고 수소 발생수율 96.4%를 얻었다.

− Recently, there are many efforts focused on development of more economical non-fluorinated membranes for PEMFCs (Proton Exchange Membrane Fuel Cells). In this study, to test the durability of sPEEK MEA (Membrane and Electrode Assembly), ADT (Accelerated Degradation Test) of MEA degradation was done at the condition that membrane and electrode were degraded simultaneously. Before and after degradation, I-V polarization curve, hydrogen crossover, electrochemical surface area, membrane resistance and charge transfer resistance were measured. Although the permeability of hydrogen through sPEEK membrane was low, sPEEK membrane was weaker to radical evolved at low humidity and OCV condition than fluorinated membrane such as Nafion. Performance after MEA degradation for 144 hours and 271 hours were reduced by 15% and 65%, respectively. It was showed that the main cause of rapid decrease of performance after 144 hours was shorting due to Pt/C particles in the pinholes.

Nanoscale drug carriers fabricated by phospholipid end-capped polyurethane bearing acetal backbones that degrade in acidic conditions are fabricated. These micelles effectively allow drugs to enter the blood circulation, and then disintegrate in acidic endosomes and lysosomes for intelligent delivery of payloads.

최근에 저가의 고분자 전해질 연료전지(Proton Exchange Membrane Fuel Cells, PEMFC)용 비불소계 전해질 막 연구개발이 활발히 진행되고 있다. 본 연구에서는 sulfonated Poly(ether ether ketone)(sPEEK)막의 특성을 술폰화도, 상대습도, 단위 전지 온도에 따라 PEMFC 운전 조건에서 비교하였다. I-V 분극곡선, 수소투과도, 전기화학적 표면적, 막 저항 및 부하 전달 저항 등을 측정·분석했다. 술폰화도와 온도, 상대습도가 높을수록 성능이 높았으며, 특히 낮은 슬폰화도와 낮은 상대습도에서 이온 전도도 감소 때문에 성능이 큰 폭으로 감소함을 확인하였다.Abstract − Recently, there are many efforts focused on development of more economical non-fluorinated membranesfor use in PEMFCs (Proton Exchange Membrane Fuel Cells). In this study, characteristics of sulfonated Poly(ether etherketone) (sPEEK) were compared according to degrees of sulfonation (DS), relative humidity, cell temperatures at PEMFCoperation condition. I-V polarization curve, hydrogen crossover, electrochemical surface area, membrane resistance andcharge transfer resistance were measured. sPEEK membrane showed high performance at high DS, high temperatureand high relative humidity, in particular, performance of sPEEK membrane decreased largely due to low ionic conduc-tivity at low DS and low relative humidity.Key words: PEMFC, sPEEK, Performance, Degrees of sulfonation, Relative Humidity, Cell Temperatures, Ionic Conductivity

Anode는 효소를 이용한 효소전극과 cathode는 PEMFC용 전극을 이용해 효소연료전지를 구동하였다. 효소 anode는graphite 분말과 효소로서 글루코스 산화제, 전자매개체로 ferrocene을 혼합해 압축해서 만들고 Nafion 이오노머로 코팅하였다. Anode 제조조건을 변화시키며 성능을 측정해 효소 anode 제조 최적조건을 찾았다. 효소 anode 압축 시 최적 압력은 8.89 MPa이고, 효소 anode의 graphite 성분비가 60%일 때 최고의 출력밀도를 나타냈다. Anode 기질 용액의 최적glucose 농도는 1.7mol/l이었다. 효소 anode는 Nafion 용액에 1초, 2회 침지에 의해 안정화되었다. Abstract − Enzyme fuel cells were operated with cells composed of enzyme anode and PEMFC cathode. Enzymeanodes was fabricated by compression of a mixture of graphite particle, glucose oxidase(Gox) as a enzyme and ferro-cene as a redox mediator, and then coated with Nafion ionomer solution. Performances of enzyme unit cell were mea-sured with variation of anode manufacture factors, to find optimum condition of enzyme anode. Optimum pressure was8.89MPa for enzyme anode pressing process. Highest power density was obtained at 60% graphite composition inenzyme anode. Optimum glucose concentration was 1.7 mol/l in anode substrate solution. The enzyme anode was sta-bilized by two times of deeping in Nafion solution for 1 sec.Key words: Enzyme fuel cells, Performance, Pressing Anode, Fabrication method, Glucose oxidase, Stability

A powerful T2-weighted magnetic resonance imaging (MRI) contrast agent with targetability has been fabricated by encapsulating manganese ferrite (MnFe2O4) nanoparticles (NPs) into biocompatible L-α-phosphatidylethanolamine-hyperbranched polyglycidol (PE–HBPG) bioconjugates covalently functionalized with folic acid (FA). The PE–HBPG is synthesized by anionic ring-opening multibranching polymerization of glycidol using soy-based PE as an initiator. FA is then conjugated onto the periphery of PE–HBPG for targeting tumor cells which have over-expressed the folate receptor. The highly monodisperse MnFe2O4 NPs with uniform size (7–10 nm) stabilized by oleylamine are labeled with the PE–HBPG–FA by ligand exchange reaction to fabricate the water-soluble and biocompatible hybrid NPs, MnFe2O4@ PE–HBPG–FA, showing targetability through receptor-mediated cellular binding and uptake. The transverse relaxivity value of MnFe2O4@PE–HBPG–FA is 140.56 mM−1 s−1, higher than those of conventional superparamagnetic iron oxide particle contrast agents.

Atopic dermatitis (AD) is a chronic inflammatory skin disease resulting pruritic, erythema, edema, excoriation, and thickening of the skin, and thus leads to significant impairment in the patient's life. The objective of this study is to develop a steroid drug [prednisolone (PS)]-loaded coatable hydrogel for the treatment of AD. PS-loaded hydrogel was composed of PVA entrapped in mildly crosslinked alginate (PS-loaded PVA/ALG hydrogel). The PS concentration to be loaded in the hydrogel that takes AD efficacy without cell necrosis was determined from the cytotoxicity test using human dermal fibroblasts. The in vivo therapeutic effects for AD of the PS-loaded PVA/ALG hydrogel were evaluated using 2, 4-dinitrochlorobenzene (DNCB)-induced AD Balb/c mouse model. The PS-loaded hydrogel has an appropriate viscosity for easy application and provides moisturizing effect on the skin, as well as anti-inflammatory effect by the sustained drug release for effective AD treatment. From the animal study, the PS-loaded PVA/ALG hydrogel showed effective suppressions of various AD symptoms such as ear edema, pruritus, high IgE levels, epidermal swelling, and mast cell infiltration. Our findings suggest that the PS-loaded coatable PVA/ALG hydrogel may be a promising therapeutic system for the treatment of AD.

A high composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was simultaneously extracted from soybean lecithin by using a mixed solvent consisting of ethanol and chloroform. The addition of chloroform in ethanol improved the total extraction yield to give high a composition of PC and PE. Thus, the best extraction yield (52%) of PC and PE was achieved at an ethanol/chloroform ratio of 6/4 (v/v). Molecular dynamics calculations of the amorphous cell bearing PC, PE, and solvent molecules were performed in order to understand the distribution of PC and PE molecules in specific solvent conditions. The extraction yield was also sensitive to extraction temperature, time and liquid to solid ratio. The extracted PC and PE mixture was successfully purified by flash chromatography using chloroform/methanol (8/2 v/v) as eluting solvent. The purified yields of PE and PC from lecithin extract were 16 and 35%, respectively. The structure of the extracted products was characterized by thin-layer chromatography and 1H, 13C, 31P NMR, FTIR and UV/vis spectroscopies, and elemental analysis. The purity of PE and PC was higher than 95%. Practical applications: Lecithin composed of phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids is widely used in human food, animal feed, pharmaceuticals, paints, and other industrial applications. Lecithin can easily be extracted chemically using various solvents in order to obtain pure components. Due to the importance of phospholipids there have been a number of reports on the extraction of PC from lecithin; however, there have been few reports on the extraction of PE or the simultaneous extraction of PC and PE. Thus the simultaneous extraction of PC (35%) and PE (16%) from soybean lecithin by using a mixed solvent consisting of ethanol and chloroform can be a good example to obtain such components in high yields. The protocol employed here is quite straightforward so that pure PC and PE can be obtained economically and may attract interest on mixed solvent systems for the simultaneous extraction of lecithin components. Phosphatidylcholine and phosphatidylethanolamine were simultaneously extracted from soybean lecithin by using a mixed solvent consisting of ethanol and chloroform.

As a means of developing biologically active compounds, a series of α-hydroxyphosphonates, ArC(OH)PO(OR)2 (Ar = 5-G-2-OHPh; R = Me, Et, iPr, Bu; G = H, Br, Cl, NO2), have been synthesized by reacting diversely substituted salicylaldehydes with dialkyl phosphites by employing the Pudovik reaction in the presence of phospho sulfonic acid under neat conditions. The cytotoxicity of the compounds was tested in two human cancer cell lines by using MTT assay. Compounds bearing R = Et; G = Cl, R = Bu; G = Cl, and R = Et; G = NO2 showed good anticancer activity.

A new design procedure of a two-way liquid damper which reduces wind-induced responses of a tall building is presented as a quick guide for structural engineers. The two-way liquid damper combines the (1) Tuned Liquid Column Damper (TLCD) in which liquid moves through a U-shape tube and the (2) Tuned Sloshing Damper (TSD) in which liquid sloshes within a container, respectively for two orthogonal directions. Dimensions of the damper, such as horizontal liquid column length and the thickness of the TLCD, the width of the TSD, and liquid height are determined given the condition of tuning the natural frequencies of liquid motion in the damper to those of the building. The design procedure is a trial and error process of satisfying geometrical constraints (i.e., maximum space where the damper is installed) and varying controlled response factors (i.e., performance of vibration attenuation). A design example of the damper is illustrated in the paper for its installation at a 64-story reinforced-concrete residential building.

In this study, PANI nanocomposite with modified multi-walled carbon nanotube (mMWCNT) was prepared. Herein MWCNT was modified by Friedel-Crafts acylation reaction. The dc conductivity of PANI nanocomposite according to the content of mMWCNT was measured by four-point probe. The highest conductivity of 9.49 S/cm was obtained in case of PANI nanocomposite with 3 wt% of mMWCNT. And it could be known that MWCNT was less damaged by the modification of Friedel-Crafts acylation reaction (mMWCNT) than strong acid treatment (aMWCNT), so the thermal stability of PANI nanocomposite was higher than that of pure PANI. And the morphology and crystallinity of the PANI nanocomposite were investigated by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and X-ray diffraction. Also the electrochemical property of PANI nanocomposite was intensively investigated by cyclic voltammetry (CV) and charge-discharge capacity. From the CV data, it could be known that the charge-discharge capacity of PANI nanocomposite electrode was improved compared to pure PANI and PANI + aMWCNT electrodes.