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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.

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.

During seedling production, growth control of seedlings is an important problem because the overgrowth of seedlings causes a decrease of seedling quality and has disadvantages after transplanting. In this study, we aim to evaluate the possibility of replacing chemical plant growth regulators using light quality in a closed-type plant production system (CPPS) for cucumber seedling production. We used various light treatments, such as monochromatic or combined red (R) and blue (B), and combined R and B with UV-A or Far-red (Fr) light, to compare with a chemical plant growth regulator conventionally using in nursery farms. The combined R and B treatment decreased stem elongation and increased dry matter and compactness. UV-A treatment increased compactness but did not significantly affect the stem elongation or dry matter. Fr increased stem elongation and stem diameter and decreased compactness and dry matter. In leaf growth, combined R and B treatments and UV-A treatments increased leaf area, specific leaf weight, and SPAD value, and decreased leaf shape index. Fr treatments increased leaf area and leaf shape index and decreased specific leaf weight (SLW) and SPAD values. Cucumber seedlings have many different morphological changes, and R5B5 light quality was more effective in growth control due to higher compactness than chemical plant growth regulators. Also, R5B5 light quality has increased seedling quality, such as dry matter and SLW compared with fluorescent lamps. Thus, the use of light quality is a possible alternative to a chemical plant growth regulator.

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.

This study aims to determine the effect of different CO2 concentrations and light intensities on the growth, photosynthetic rate, and bioactive compound content of Glehnia littoralis Fr. Schmidt ex Miquel in a closed-type plant production system (CPPS). The plants were transplanted into a deep floating technique system with recycling nutrient solution (EC 1.0 dS&middot, m-1 and pH 6.5) and cultured for 96 days under a temperature of 20 &plusmn, 1 &deg, C, a photoperiod of 12/12 h (light/dark), and RGB LEDs (red:green:blue = 7:1:2) in a CPPS. The experimental treatments were set to 500 or 1500 &micro, mol∙mol&minus, 1 CO2 concentrations in combination with one of the three light intensities: 100, 200, or 300 &micro, mol∙m&minus, 2∙s&minus, 1 photosynthetic photon flux density (PPFD). The petiole length of G. littoralis was the longest in the 500 &micro, 1 CO2 concentration with the 100 &micro, 1 PPFD. The fresh weight (FW) and dry weight (DW) of shoots and roots were the heaviest in the 300 &micro, 1 PPFD regardless of the CO2 concentration. Higher CO2 concentrations and light intensities produced the greatest photosynthetic rates. However, the SPAD value was not significantly different between the treatments. Higher light intensities produced greater content per biomass of chlorogenic acid and total saponin, although the concentration per DW or FW was not significantly different between treatments. The first and second harvest yields were the greatest in the 300 &micro, 1 PPFD, regardless of the CO2 concentration. These results show that the 300 &micro, 1 PPFD enhanced the growth, photosynthetic rate, and bioactive compound accumulation of G. littoralis, regardless of the CO2 concentration in a CPPS.

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

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.

Strawberry (Fragaria &times, ananassa Duch.) is an important horticultural crop that is vegetatively propagated using runner plants. To achieve massive production of runner plants, it is important to transfer the assimilation products of the mother plant to the runner plants, and not to the runner itself. Application of prohexadione&ndash, calcium (Pro&ndash, Ca), a plant growth retardant with few side effects, to strawberry is effective in inhibiting transport of assimilates to runners. This study aimed to determine the optimum application method and concentration of Pro&ndash, Ca on the growth characteristics of mother plants, runners, and runner plants for the propagation of strawberry in nurseries. Pro&ndash, Ca was applied at the rate of 0, 50, 100, 150, or 200 mg&middot, L&minus, 1 (35 mL per plant) to plants via foliar spray or drenching under greenhouse conditions at 30 days after transplantation. Petiole lengths of mother plants were measured 15 weeks after treatment, growth was suppressed at the higher concentrations of Pro&ndash, Ca regardless of the application method. However, the crown diameter was not significantly affected by the application method or Pro&ndash, Ca concentration. The number of runners was 7.0 to 8.2, with no significant difference across treatments. Runner length was shorter at higher concentrations of Pro&ndash, Ca, especially in the 200 mg&middot, 1 drench treatment. However, fresh weight (FW) and dry weights (DW) of runners in the 50 mg&middot, 1 Pro&ndash, Ca drench treatments were higher than controls. Foliar spray and drench treatments were more effective for runner plant production than the control, a greater number of runner plants were produced with the 100 and 150 mg&middot, Ca foliar spray treatment and the 50 and 100 mg&middot, 1 drench treatment. The FW and DW of the first runner plant was not significantly different in all treatments, but DW of the second runner plant, and FW and DW of the third runner plant were greatest in the 50 mg&middot, Ca drench treatment. These results suggested that growth and production of runner plants of Maehyang strawberry were greatest under the 50 mg&middot, Ca drench treatment.