Mechanical and Pore Properties of Concrete Using Basalt-Based Recycled Aggregates According to Mixture Conditions.

This study investigated recycled aggregates of Jeju Island-where porous basalt exists as a natural aggregate-and is a study aimed at verifying the applicability of the basalt-based recycled aggregate in the field. To this end, the application properties of concrete were analyzed using the quality improvement of the recycled aggregate (PRA), the type of fine aggregate received in the region, and the cement content as variables. In an experiment using concrete in which 50% of the PRA was replaced with basalt (BA), the air content of the fresh concrete decreased due to the increasing solid content of the aggregate when PRA and fine aggregates (with an even particle size distribution) were used. Regarding the properties of the hardened concrete, when the PRA and fine aggregate (with a high fineness modulus) were used, the compressive strength was 33.6 MPa and the modulus of elasticity was 23.1 GPa, which are higher than those of the BA specimen. The resistance to carbonation increased due to the improved quality of the PRA specimen. Pores that are 0.3 mm in size or larger decreased when the PRA and fine aggregates of even particle sizes were used. This form of pore reduction was found to have a direct correlation with the improvement of mechanical properties.

Study on Mechanical Properties of Concrete Using Basalt-Based Recycled Aggregate and Varying Curing Conditions.

To replace porous basalt, the mechanical properties of concrete with recycled resources and durability improvement were analyzed in this study. The analysis was based on the quality improvement of recycled aggregate, use of fly ash, and changes in curing conditions. Basalt aggregate (BA) with a 3% water absorption, raw recycled aggregate and basalt (RRA), and improved recycled aggregate and basalt (PRA) were the main experimental variables. As PRA was applied to concrete, the compressive strength was lower than that of the specimen comprising BA in the normal strength region, but the modulus of elasticity (22.9 GPa) was equivalent or higher. The initial drying shrinkage increased because of the use of basalt-based recycled aggregate (B-RA). The drying shrinkage of PRA was similar to that of BA with an average difference of <7% as the age increased. The specimens subjected to steam curing exhibited the lowest drying shrinkage. These results showed that pores in the old paste of recycled aggregate increased freeze−thaw resistance because of the increase in the spacing factor. Although the PRA did not satisfy the quality criteria, the efficient use of recycled aggregate achieved an equivalent or higher performance than that of concrete comprising BA and improved durability.

Mechanical Properties of Basalt-Based Recycled Aggregate Concrete for Jeju Island.

Recycled aggregate is essential to protect Jeju Island's natural environment, but waste concrete, including porous basalt, is a factor that lowers the quality of recycled aggregate. Therefore, an experiment was conducted to analyze the properties of concrete application of basalt-based recycled aggregate (B-RA) through quality improvement. The absorption of the B-RA ranged from 3-5%; restricting its absorption to less than 3% was challenging owing to its porosity and irregular shape. However, the increase in the solid volume percentage of the concrete when replacing 25 or 50% of fresh basalt aggregate with recycled basalt aggregate improved the mechanical performance of the concrete, especially at 25%, for which a compressive strength of 55.9 MPa and modulus of elasticity of 25.9 GPa exceeded those of concrete with fresh basalt aggregate. Moreover, increasing the replacement ratio of the fresh basalt with recycled aggregate reduced the slump and decreased the air content, consequently increasing the concrete drying shrinkage. However, the replacement of fresh basalt aggregate with recycled basalt aggregate unaltered the mechanical performance of the concrete. The results indicate that efficient use of recycled aggregates can yield superior performance to that of fresh basalt, irrespective of aggregate quality.

A study of skin characteristics with long-term sleep restriction in Korean women in their 40s.

BACKGROUND: Previous studies have demonstrated increased pore size and darkening skin color with total sleep deprivation. There are many studies of skin characteristics with short-term sleep restriction, but there are few studies on skin characteristics when sleep is restricted more than three consecutive days. This study evaluated skin changes with sleep limited to 4 hours per night for six nights. MATERIALS AND METHODS: The study included 32 Korean women in their 40s. Skin hydration, desquamation, barrier recovery, texture, gloss, transparency, elasticity, crow's feet, frown lines, and color were measured. Individual sleep time was monitored by smartwatches. Subjects slept 8 hours per night for six nights in week one and 4 hours per night for six nights in week two. RESULTS: Skin hydration was significantly reduced after 1 day of sleep deprivation, and it continued to decrease. Skin gloss, desquamation, transparency, elasticity, and wrinkles were significantly aggravated after 1 day of sleep deprivation. Skin texture was significantly aggravated on the fourth day of sleep restriction. Elasticity was most affected by reduced sleep, with a standardized coefficient of -.320, indicating a significant decrease over time as compared to other characteristics. CONCLUSION: Skin hydration was gradually decreased with sleep restriction. Skin texture did not change after only 1 day of sleep restriction. It is a new finding that elasticity decreases more than other skin characteristics with prolonged sleep restriction.

Efficacy and safety of a novel, soluble microneedle patch for the improvement of facial wrinkle.

BACKGROUND: Various kinds of functional cosmetics are on the market, although there are a variety of opinions concerning the actual effect. Transdermal microneedle patch has been introduced as a newly developed device for drug delivery through the skin. OBJECTIVE: This study was conducted to verify the face skin improvement effect and safety of a novel cosmetic microneedle patch. METHODS: A total of 84 Korean females finished this prospective clinical trial. The subjects were divided into 3 groups: (1) soluble hyaluronic acid (HA) microneedle patch alone, (2) soluble HA microneedle patch plus adenosine wrinkle cream, and (3) adenosine wrinkle cream alone. The treatments were applied to the crow's feet and nasolabial fold wrinkle for 12 weeks. The test areas were measured before treatment and at 4, 8, and 12 weeks after use of the test product. At the completion of the testing period of the trial, the global assessment of efficacy and product preferences were surveyed from the subjects. RESULTS: Combination treatment with wrinkle cream and microneedle patch significantly improved Merz scale for crow's feet and nasolabial folds, compared to the sole application of wrinkle cream or patch. Measurement on the crow's feet showed an overall improvement in all 3 groups, yielding no significant differences among the groups. No serious adverse effects were observed during the follow-up period. CONCLUSION: Combination application of a soluble microneedle patch and wrinkle cream was an effective treatment in improving facial wrinkles, thus enhancing skin rejuvenation.

A new method for transduction of mesenchymal stem cells using mechanical agitation.

Applications of bone marrow-derived mesenchymal stem cells in gene therapy have been hampered by the low efficiency of gene transfer to these cells. In current transduction protocols, retrovirus particles with foreign genes make only limited contact with their target cells by passive diffusion and have short life spans, thereby limiting the chances of viral infection. We theorized that mechanically agitating the virus-containing cell suspensions would increase the movement of viruses and target cells, resulting in increase of contact between them. Application of our mechanical agitation for transduction process has increased the absorption of retrovirus particles more than five times compared to the previous static method without changing cell growth rate and viability. The addition of a mechanical agitation step increased transduction efficiency to 42%, higher than that of any other previously-known static transduction protocol.