The solubilities of different multicomponent lanthanide oxide (Ln2O3) solid solutions including binary (Ln1 and Ln2 = La, Nd, Eu, or Tm), ternary (Ln1, Ln2, and Ln3 = La, Nd, Eu, or Tm), and higher systems (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were studied after aging for four weeks at 60°C. Our recent study revealed that the phase transformations in binary ((La, Nd) and (La, Eu)) and ternary (La, Nd, Eu) systems are responsible for the formation of (La, Nd)(OH)3, (La, Eu)(OH)3, and (La, Nd, Eu)(OH)3 solid solutions, respectively. The variations in the mole fractions of La3+, Nd3+, and Eu3+ in the sample solutions of these hydroxide solid solutions indicated that a thermodynamic equilibrium might account for the apparent La, Nd, and Eu solubilities. Conversely, the binary and ternary systems containing Tm2O3 as the heavy lanthanide oxide retained the oxide-based solid solutions, and their solubility behaviors were dominated by their congruent dissolutions. In the higher multicomponent system, the X-ray diffraction patterns of the solid phases, before and after contact with the aqueous phase indicated the formation of a stable oxide solid solution and their solubility behavior was explained by its congruent dissolution.

최근 들어 여러 산업 분야에 활발히 사용되고 있는 고분자 분리막은 화학구조의 제어나 제막공정에서의 물리적 특성 제어뿐만 아니라 다양한 소재와 혼합된 복합막 제조를 통해서 고유의 특성을 부여할 수 있는 장점을 가지고 있다. 본 연구에서는 분리막 제조 시에 누에(Bombyx mori)가 생산한 친환경 천연소재로 활용 가능성이 넓은 실크 고분자의 복합막 제조 시 다른 소재와의 혼화성 지표로 사용할 수 있는 용해도 파라미터를 분자동역학을 이용하여 계산하였다. 역시 친환경성 및 생체적합성을 갖고 있는 polyvinylalcohol (PVA)의 용해도 파라미터를 분자동역학을 이용하여 계산 후 서로 비교하였을 때 두 고분자 소재가 비슷한 용해도 파라미터 값을 갖는 것을 확인하였다. 결론적으로, 두 고분자가 서로 잘 혼합될 수 있음을 이론적으로 증명하였고, 실제 실험을 통해서도 이를 확인할 수 있었다.

A safety assessment of radioactive waste repositories is a mandatory requirement process because there are possible radiological hazards owing to radionuclide migration from radioactive waste to the biosphere. For a reliable safety assessment, it is important to establish a parameter database that reflects the site-specific characteristics of the disposal facility and repository site. From this perspective, solubility, a major geochemical parameter, has been chosen as an important parameter for modeling the migration behavior of radionuclides. The solubilities were derived for Am, Ni, Tc, and U, which were major radionuclides in this study, and on-site groundwater data reflecting the operational conditions of the Gyeongju low and intermediate level radioactive waste (LILW) repository were applied to reflect the site-specific characteristics. The radiation dose was derived by applying the solubility and radionuclide inventory data to the RESRAD-OFFSITE code, and sensitivity analysis of the dose according to the solubility variation was performed. As a result, owing to the low amount of radionuclide inventory, the dose variation was insignificant. The derived solubility can be used as the main input data for the safety assessment of the Gyeongju LILW repository in the future.

In our previous study, exogenous plasminasminogen activators (PAs) influenced to fertility of boar spermatozoa via reduction of zona pellucida (ZP) resistance against protease and number of sperm binding ZP. plasminasmin (plasmin), is converted by PAs, is an important enzyme to degrade extracellular matrix and it is closely associated with fertilization process. Therefore, the aim of present study was to confirm changes of sperm penatration and ZP solubility by plasmin during in vitro fertilization (IVF). The cumulus-oocyte complasminexes (COCs) were aspirated from the antral follicles 3-6 mm in diameter and matured for 44 hours. Then, the cumulus cells were removed and denuded oocytes were co-incubated with spermatozoa for 18-20 hours in IVF medium containing 100 ng/ml plasmin. The number of sperm binding ZP and ZP solubility were measured using hoechst 33342 and 0.5% (w/v) pronase, respectively. Aceto-orcein stain was used to assess fertilization parameters. In results, sperm penetration did not affect by plasmin treatment during fertilization. Hoewever, treatment of plasmin decreased monospermic fertilization and IVF efficiency compared with control group (p<0.05). Furthermore, the number of penetrated sperm and pronucleus formation per zygote in plasmin group was significantly increased compared with control group (p<0.05). Despite of reduced monospermic fertilization by plasmin treatment, the number of sperm binding ZP was significantly higher in non-treated zygote than plasmin-treated zygote (p<0.05). Similar with previous study, ZP digestion time was reduced by plasmin treatment (p<0.05). These findings shown that plasminasmin during fertilization enhance the penetration of spermatozoa into ZP via increasing of ZP solubility and it was correspond with our previous results that fertility of spermatozoa during IVF was increased by exogenous urokinase-type PA treatment via sperm-ZP binding and increase of ZP solubility. Therefore, during the fertilization process, plasmin that is converted by PAs from oviduct epithelial cells might be closely associated with degradation of ZP proteins for penetration of sperm. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Education) (2016R1D1A1B03931746).

Rice starch is a natural source of polysaccharides that can be used as a stabilizer, thickener, binder and fat mimetic in various foods. However, untreated starch possesses limited functionality due to its poor water solubility with a densely packed granular structure of amylopectin and amylose chains. Also, it shows weak complexing ability as the only amylose participates in complex formation with a chemical compound. The objective of this study is to improve complexation ability and water solubility of rice starch by 4-α-glucanotransferase (4αGTase) treatment. Complex forming capacity was examined by fully dissolving the 4αGTase-treated rice starch in 90% DMSO by mechanical stirring and mixing with iodine solution with following UV/Vis spectrophotometer measurements. Water solubility of the starch was measured by dissolving in distilled water (5% w/v) with mechanical stirring at 25 °C and 60 °C, and drying the supernatant after centrifugation. The complexing ability of starch was enhanced after the 4αGTase treatment. The absorbance at a peak wavelength increased, as well as the peak wavelength was shifted leftward, indicating that the type of molecules got involved in the complexation was changed. Alteration in the molecule composition and starch composition during the enzyme treatment may be due to disproportionation and cyclization by the 4αGTase. The water solubility (%) of the starch at 25 °C and 60 °C increased by 28-fold with the 4αGTase treatment regardless of the treatment time. The untreated starch showed solubility of 0.15 %, while the solubility of the 4αGTase-treated starch was about 4 - 4.5 % (w/v). It may be due to heat treatment and recrystallization which melted a granular structure and made it easier to be solubilized in water. Moreover, the increased solubility might be attributed to increase in the number of short branched chains and decrease in molecular weight.

고분자 분리막을 통한 기체 분리는 기체의 용해 및 확산으로 진행되며 따라서 기체 분리 성능은 기체의 용해도 또는 확산도에 좌우된다. 이에 이산화탄소와 같은 극성 기체의 용해도를 향상시키기 위해 acylation, bromination, sulfonation과 같은 화학적 개질을 통한 연구들이 진행되었으며 또한 술폰산기 를 가지는 고분자에 금속이온을 치환시켜 이산화탄소 선택도를 증가시킨 연구가 보고되었다. 본 연구에서는 biphenol기와 fluorene기를 가지는 Sulfonated Poly(arylene ehter sulfone) (SPAES) 고분자 분리막을 제조하였으며 술폰화 정 도와 치환된 극성 그룹의 종류에 따른 기체투과특성을 알아보고자 하였다.

Although carnosic acid (CaA) is known as one of the useful polyphenolic compounds due to its antimicrobial and antioxidant activities, it is limited to use as aqueous solution because of its low solubility and unstability. The objective of this study was to investigate the capability of CA to improve the solubility of CaA by forming an inclusion complex in comparison with cyclodextrin (CD) and maltodextrin (MD). Enzymatically-produced CA was reacted with CaA in aqueous solution to form a complex using a freeze-drying. And the formation of complex between CaA and CA was identified by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and field emission scanning electron microscope (FESEM). As a result of XRD and DSC analysis, disappearance of characteristics of CaA that was reacted with CA could be indicated the complex formation between CaA and CA. The formation complex of CaA with CA was also confirmed through the change in morphology of CaA and CA in the electron micrograph result. Aqueous solubility of CaA with various concentrations (1, 5, 10, 20, 30%) of CA was measured by absorbance change at 285 nm. As a result, the solubility of the CaA was significantly increased with increasing CA concentration. At 30% CA, the maximum solubility of CaA was 0.095% (w/v) in solution, which was approximately 3 times higher than that of free CaA (0.033%). The effect of inclusion complex with CA on the solubility of CaA was superior than that with CD (0.057%) and MD (0.066%). These results indicated that the effects on the solubility and formation abilities of inclusion complex were associated with host materials and its concentration rate. This study confirmed that the CA can be a viable solution to improve the aqueous solubility of CaA. Further investigation is still needed to understand the effect of inclusion complex with CA.

Recently, there is a growing interest of consumers in natural products thus a large number of natural preservatives have been studied as food additives. Among those natural preservatives, rosemary extract are commonly used by the food industry to extend the shelf life of several products. Nevertheless, the incorporation of the rosemary extract in food matrix is highly limited due to the low water solubility and poor chemical stability of constituents of rosemary extract. In this context, it is needed to find a way that can improve the water solubility to incorporate rosemary extract into aqueous system like foods. Hence, in this study we added surfactants that have a relatively high hydrophilic-liphophilic balance number into rosemary extract solution to increase the water solubility of rosemary extract and then investigated the microbial activities of rosemary extract with surfactants. Tween 20, decaglycerol monooleate, decaglycerol laurate and decaglycerol myristate were used in a range 0.1~4% and rosemary-surfactant solution was prepared by dissolving rosemary in surfactant added phosphate buffer (pH 7) as much as extract can be dissolved. Water solubility of rosemary-surfactant solution were examined by observance of the UV-vis spectra. The antimicrobial effects rosemary-surfactant solution on B.subtilis were also examined by paper disc diffusion method. Rosemary extract showed poor solubility in normal phosphate buffer but its water solubility was highly increased when surfactant was added. This tendency was lasted at all types of surfactant. This is because of amphipathic property of surfactant. Antimicrobial effect to B.subtilis was observed when a relatively lower concentration of surfactants were used, however, not in high concentrations. This result might be attributed to the formation of surfactant micelles containing rosemary extract when a relatively higher concentration of surfactants were used. The information presented may be useful for the development of a new rosemary-loaded delivery systems.

고분자 분리막을 통한 기체 분리메커니즘은 기체의 용해 및 확산으로 진행 되어진다. 따라서 기체 분리 성능은 용해도 또는 확산도에 좌우되어진다. 이에 연구자들은 산화탄소와 같은 극성 기체의 용해도를 향상시키기 위해 acylation, bromination, sulfonation과 같은 화학적 개질을 통한 연구들을 진행하였고 또한 술폰산기를 가지는 고분자에 금속이온을 치환시켜 이산화탄소 선택도를 증가시킨 연구가 진행되어 보고되었다. 본 연구에서는 biphenol기와 fluorene기를 가 지는 Sulfonated Poly(arylene ehter sulfone) (SPAES) 고분자 분리막을 제조하였 으며 술폰화 정도와 치환된 극성 그룹의 종류에 따른 기체투과특성을 알아보고자 하였다.

분리막 분야에서, solubility parameter의 계산은 고분자 합성 단계에서 뿐만 아니라 투과성능 분석 등에 있어서 매우 중요한 역할을 하고 있다. 이를 위하여, 전통적으로 Hildebrand solubility parameter가 가장 널리 쓰여져 왔으며, 보다 세세한 분자간력의 기여도를 계산하기 위하여, Hansen solubility parameter와 같은 다차원 solubility parameter 계산법도 활발히 활용되고 있다. 본 연구에서는 이러한 계산에 분자 동력학(MD) 기술을 적용함으로써, 기존의 경험적인 방법에 기반한 계산법들의 한계를 극복하여, 좀 더 다양한 여러 분리막 소재 및 관련 화학 물질들의 solubility parameter 계산 방법에 대하여 논의하고자 한다.

고분자 분리막을 통한 기체 분리는 기체의 용해 및 확산으로 진행되며 따라서 기체 분리 성능은 기체의 용해도 또는 확산도에 좌우된다. 이산화탄소와 같은 극성 기체의 용해도를 향상시키기 위해 acylation, bromination, sulfonation과 같은 화학적 개질을 통한 연구들이 진행되었으며 또한 술폰산기를 가지는 고분자에 금속이온을 치환시켜 이산화탄소 선택도를 증가시킨 연구가 보고되었다. 본 연구에서는 biphenol기와 fluorene기를 가지는 Sulfonated Poly(arylene ehter sulfone) (SPAES) 고분자 분리막을 제조하였으며 술폰화 정도와 치환된 극성 그룹의 종류에 따른 기체투과특성을 알아보고자 하였다.