• Steel and Composite Structures
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• v.3 no.4
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• pp.243-260
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• 2003

This paper reports on the development of a new composite slab system that uses a large- lipped steel channel and reinforced concrete. The advantages of this new system are that it serves as both a structural unit and an unsupported form and it has a secondary structural barrier function. A concrete pouring test was carried out for the large-lipped steel channel. Full-scale tests were carried out to assess the flexural strength-deformation characteristics and structural mechanics of the composite slab. The barrier mechanics of the steel channel concrete element (referred to as the SC subunit) of the composite slab are examined. The test results indicate that the new composite slab has excellent strength, ductility characteristics, and a structural barrier function in its SC subunit that is highly effective against severe loading.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1130-1135
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• 2003

The need to increase the reliability of a structural system has been significantly brought in the procedure of real designs to consider, for instance, the material properties or geometric dimensions that reveal a random or incompletely known nature. Reliability based design optimization of a real system now becomes an emerging technique to achieve reliability, robustness and safety of these problems. Finite element analysis program and the reliability analysis program are necessary to evaluate the responses and the probabilities of failure of the system, respectively. Moreover, integration of these programs is required during the procedure of reliability based design optimization. It is well known that reliability based design optimization can often have so many local minima that it cannot converge to the specified probability of failure. To overcome this problem, barrier function method in reliability based design optimization is suggested. To illustrate the proposed formulation, reliability based design optimization of a bracket is performed. AMV and FORM are employed for reliability analysis and their optimization results are compared based on the accuracy and efficiency.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.93-102
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• 2021

This paper describes the process of developing a concrete median barrier of SB4 grade with anti-glare function. The development section has a height and width of 1,270mm and 560mm, respectively. A wire mesh is placed in the center of the cross section to improve the protection performance. Collision analysis predicted that this section satisfies the strength and occupant protection performance, and that no damage to the barrier occurs. In the actual collision test, it was confirmed that this section satisfies the strength and occupant protection performance. However, damage was observed on two concrete barrier when the truck crashed. In order to improve the accuracy of the collision analysis of the concrete barrier in the future, it is considered that a study on the model development and continuous collision analysis method for domestic commercial vehicles should be carried out.

• Biomolecules & Therapeutics
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• v.23 no.3
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• pp.207-217
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• 2015

Skin is the first line of defense for protecting our bodies against external perturbations, including ultraviolet (UV) irradiation, mechanical/chemical stress, and bacterial infection. Nutrition is one of many factors required for the maintenance of overall skin health. An impaired nutritional status alters the structural integrity and biological function of skin, resulting in an abnormal skin barrier. In particular, the importance of micronutrients (such as certain vitamins and minerals) for skin health has been highlighted in cell culture, animal, and clinical studies. These micronutrients are employed not only as active compounds in therapeutic agents for treating certain skin diseases, but also as ingredients in cosmetic products. Here, the author describes the barrier function of the skin and the general nutritional requirements for skin health. The goal of this review is to discuss the potential roles and current knowledge of selected micronutrients in skin health and function.

• Biomolecules & Therapeutics
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• v.27 no.2
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• pp.222-230
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• 2019

Intestinal barrier dysfunction always accompanies cirrhosis in patients with advanced liver disease and is an important contributor facilitating bacterial translocation (BT), which has been involved in the pathogenesis of cirrhosis and its complications. Several studies have demonstrated the protective effect of Vitamin D on intestinal barrier function. However, severe cholestasis leads to vitamin D depletion. This study was designed to test whether vitamin D therapy improves intestinal dysfunction in cirrhosis. Rats were subcutaneously injected with 50% sterile $CCl_4$ (a mixture of pure $CCl_4$ and olive oil, 0.3 mL/100 g) twice a week for 6 weeks. Next, $1,25(OH)_2D_3$ ($0.5{\mu}g/100g$) and the vehicle were administered simultaneously with $CCl_4$ to compare the extent of intestinal histologic damage, tight junction protein expression, intestinal barrier function, BT, intestinal proliferation, apoptosis, and enterocyte turnover. Intestinal heme oxygenase-1 (HO-1) expression and oxidative stress were also assessed. We found that vitamin D could maintain intestinal epithelial proliferation and turnover, inhibit intestinal epithelial apoptosis, alleviate structural damage, and prevent BT and intestinal barrier dysfunction. These were achieved partly through restoration of HO-1 and inhibition of oxidative stress. Taken together, our results suggest that vitamin D ameliorated intestinal epithelial turnover and improved the integrity and function of intestinal barrier in $CCl_4$-induced liver cirrhotic rats. HO-1 signaling activation was involved in these above beneficial effects.

• Journal of The Korea Institute of Healthcare Architecture
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• v.10 no.2
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• pp.125-133
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• 2004

Safety, accessibility and distinguishment as the concept of architectural planning and design are demanded in staircases due to increase of the old aged people and disabled people's enlarged social participation. In this research is tried to provide the importance of vertical walking function at the design for the staircases. For this reason, structural elements of the staircases are studied in the ergonomic aspect for barrier-free environment and a comparative study is made on the regulations of the staircases in the inside and outside of the country in disabled & aged people's view. Based on this study, the quality of the staircases in public facilities and Apartments is analyzed. As the result, it has been proved that the vertical walking function of the staircases is the most fundamental characteristic of the staircases design before everything else.

• Archives of Pharmacal Research
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• v.27 no.11
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• pp.1177-1182
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• 2004

The effect of poly[2-methacryloyloxyethyl phosphorylcholine] (pMPC) on the skin permeation property was investigated by performing in vitro skin permeation study of a model drug, nicotinic acid (NA). Effect of pMPC polymer in donor solution on skin permeation rates was evaluated using side-by-side diffusion cells. Also, the structural alterations in the stratum corneum (SC), inter-lamellar bilayer (ILB) and dermis layers in pMPC-treated and -untreated skin sections were investigated with transmission electron microscopy (TEM). The permeation profile of NA without pMPC in donor solution showed biphasic mode: initial $1^{st} phase and 2^{nd}$ hydration phase. The sudden, more than 10-fold increase in flux from the initial steady state (43.5 $\mu g/cm^2$/hr) to the $2^{nd}$ hydration phase (457.3 $\mu g/cm^2$/hr) suggests the disruption of skin barrier function due to extensive hydration. The permeation profile of NA with 3% pMPC in the donor solution showed monophasic pattern: the steady state flux (10.9 $\mu g/cm^2$/hr) without abrupt increase of the flux. The degree of NA permeation rate decreased in a concentration-dependent manner of pMPC. TEM of skin equilibrated with water or 2% pMPC for 12 h showed that corneocytes are still cohesive and epidermis is tightly bound to dermis in 2% pMPC-treated skin, while wider separation between corneocytes and focal dilations in inter-cellular spaces were observed in water-treated skin. This result suggests that pMPC could protect the barrier property of the stratum corneum by preventing the disruption of ILB structure caused by extensive skin hydration during skin permeation study.

• Journal of the Korean Magnetics Society
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• v.15 no.4
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• pp.231-235
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• 2005

We studied the microstructural evolution of ZrTM-Al (TM=Nb and Ti) alloy films, MR and electrical properties of the MTJ with $ZrTM-AlO_x$ barrier as a function of Zr/TM ratio. We observed that the ternary-oxide barrier reduced the TMR ratio due mainly to the structural defects such as the surface roughness. The change in TMR ratio and $V_h$ with Zr/TM ratio exactly corresponds to the systematic changes in the microstructural variation. Although the MTJ with ternary oxide reduced the TMR and the electrical stabilities, the junction resistances decreased as the Ti and Nb concentration increased due to the band-gap reduction caused by the formation of extra bands

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.215-224
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• 2013

Recently, many cosmetic researchers have been focused on the development of high functional cosmetics including anti-wrinkle and whitening. In these studies, they couldn't afford to pay a deep attention to stable encapsulations for unstable materials and efficient drug deliveries for them. Particularly, in order to show a degree of instant effects as cosmetics, they can't also ignore moisturizing effect enough to satisfy customers just after applying and its maintenance by improving the function of skin barrier as well as above two effects. Therefore, skin analogue systems have attracted considerable attention in the view of structural and compositional similarity to intercellular membrane in stratum corneum. And, some models for skin analogue composition were developed to improve the function of skin barrier, stably encapsulate unstable materials such as retinol, vitamin B, C, E, etc., and control their skin penetration in order to show good effects as cosmetics. In this study, we suggest the new skin analogue model having the compositional similarity as well as conventional structural ones. Our skin analogue membrane(SAM) is mainly composed of ceramide/ cholesterol/phosphatidylcholin/fatty acids and its structural defects are compensated by including cholesterol amphiphile and controlling the ratio of ceramide/cholesterol. It was possible to confirm the formation of skin analogue membrane having highly-densed multilamella structure and compare them according to the change of each ratio with a polarized microscope, X-ray diffraction. More detaily, we observed their structures with a electron microscope(TEM). Finally, we dispersed them in excess of continuous water phase, observed the formation of maltese-cross liquid crystalline and measured the efficiency of drug deliveries and moisturizing effects.

• Biomedical Science Letters
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• v.27 no.4
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• pp.231-238
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• 2021

Several structural proteins present in keratinocytes of the skin are known to play an important role in the formation of epidermal tissue and barrier function, and the absence of structural proteins in keratinocytes causes various skin diseases. In this study, 42 types of tetrapeptides derived from the sequence of Loricrin, a kind of terminally differentiating structural protein, were synthesized, and skin anti-aging properties were measured by measuring the elastase inhibition, proliferation of skin cells. The anti-aging efficacy was verified and, based on this, it succeeded in selecting one of the most excellent peptides. It is expected that the selected tetrapeptide can be used as a raw material for various cosmetics and quasi-drugs based on anti-aging and skin cell proliferation effects.