• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.356-362
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• 2010

Ceramide is important not only for the maintenance of the barrier function of the skin but also for the water-binding capacity of the stratum corneum. Although the exact role of ceramide in the human skin is not fully understood, ceramide has become a widely used ingredient in cosmetic and pharmaceutical industries. Compared with other microorganisms, yeast is more suitable for the production of ceramide because yeast grows fast and is non-toxic. However, production of ceramide from yeast has not been widely studied and most work in this area has been carried out using Saccharomyces cerevisiae. Regulating the genes that are involved in sphingolipid synthesis is necessary to increase ceramide production. In this study, we investigated the effect of the genes involved in the synthesis of ceramide, lcb1, lcb2, tsc10, lac1, lag1, and sur2, on ceramide production levels. The genes were cloned into pYES2 high copy number vectors. S. cerevisiae was cultivated on YPDG medium at $30^{\circ}C$. Ceramide was purified from the cell extracts by solvent extraction and the ceramide content was analyzed by HPLC using ELSD. The maximum production of ceramide (9.8 mg ceramide/g cell) was obtained when the tsc10 gene was amplified by the pYES2 vector. Real-time RT-PCR analysis showed that the increase in ceramide content was proportional to the increase in the tsc10 gene expression level, which was 4.56 times higher than that of the control strain.

• Journal of the Korean Society for Marine Environment & Energy
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• v.1 no.2
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• pp.27-39
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• 1998

The interaction of monochromatic incident waves with a horizontal flexible membrane is investigated in the context of two-dimensional linear hydro-elastic theory. First, analytic diffraction and radiation solutions for a submerged impermeable horizontal membrane are obtained. Second, the theoretical prediction was compared with a series of experiments conducted in a two-dimensional wave tank at Texas A&M University. The measured reflection and transmission coefficients reasonably follow the trend of predicted values. Using the developed computer program, the performance of surface-mounted or submerged horizontal membrane wave barriers is tested with various system parameters and wave characteristics. It is found that the properly designed horizontal flexible membrane can be an effective wave barrier.

• Korean Journal of Materials Research
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• v.10 no.1
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• pp.90-96
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• 2000

The effects of the type and thickness of underlayers on the crystallographic texture and the sheet resistance of aluminum thin films were studied. Sputtered Ti and Ti/TiN were examined as the underlayer of the aluminum films. The texture and the sheet resistance of the metal thin film stacks were investigated at various thicknesses of Ti or TiN, and the sheet resistance was measured after annealing at $400^{\circ}C$ in an nitrogen ambient. For the Ti underlayer, the minimum thickness to obtain excellent texture of aluminum <111> was 10nm, and the sheet resistance of the metal stack was greatly increased after annealing due to the interdiffusion and reaction of Al and Ti. TiN between Ti and Al could suppress the Al-Ti reaction, while it deteriorated the texture of the aluminum film. For the Ti/TiN underlayer, the minimum Ti thickness to obtain excellent texture of aluminum <111> was 20nm, and the minimum thickness of TiN to function as a diffusion barrier between Ti and Al was 20nm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.8
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• pp.33-41
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• 2007

The IEEE 802.11 DCF channel access function allows single transmission inside two-hop network in order to avoid collisions and eliminate the hidden and exposed terminal problems. Singular transmission capability causes data frames waiting for the entire roundtrip time in the transmitter neighborhood, and results in increased frame latency and lower network throughput. Real-time and pervasive applications are severely affected for the lower medium utilization; especially with high network traffic. This work proposes a new scheme with the help of Frame Aggregation technique in IEEE802.11n and overcomes the single transmission barrier maintaining the basic DCF functionality. Proposed scheme allows parallel transmissions in non-interfering synchronized slots. Parallel transmissions bypass the conventional physical carrier sense and random Backoff time for several cases and reduce the frame latency and increase the medium utilization and network capacity.

• Journal of Digital Contents Society
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• v.15 no.4
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• pp.501-512
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• 2014

Due to smart phones introduced since 2007, mobile contents production become activated and with this trend, attention among different age groups to production of mobile games has been growing. Whereas in the past, development of games was the domain of developers equipped with technical knowledge, provision of editor-type engines in recent times is lowering the high barrier of entry to game production. This paper proposes an event-based module design method from the perspective of general users, aimed at producing games by oneself with a Unity 3D, one of editor-type game engines. This is to plan behaviors and roles in the unit of modules in the whole process of a game to be in line with the perspective of game production by one person. Each module includes diverse events that express game characteristics. In addition, the script function provided by the Unity 3D is appropriate to embody the proposed module structure and utilizes the Unity 3D. Lastly, this study produce a simple 3D mobile casual game in order to verify whether effective game production from the planning to the development is possible through the proposed method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.226-233
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• 1999

An experimental study has been performed on natural convection heat transfer with a rapid crust formation in the molten metal pool of a low Prandtl number fluid. Two types of steady state tests, a low and high geometric aspect ratio cases in the molten metal pool, were performed. The crust thickness by solidification was measured 88 a function of boundary surface temperatures. The experimental results on the relationship between the Nusselt number and Rayleigh number In the molten metal pool with a crust formation were compared with existing correlations. The experimental study has shown that the bottom surface temperature of the molten metal layer, in all experiments. is the major influential parameter in the crust formation, duo to the natural convection flow. The Nusselt number of the case without a crust formation in the molten metal pool is greater than that of the case with the crust formation at the same Rayleigh number. The present experimental results on the relationship between the Nusselt number and Rayleigh number In the molten metal pool match well with Globe and Dropkin's correlation. From the experimental results, a now correlation between the Nusslet number and Rayleigh number in the molten metal pool with the crust formation was developed as $Nu=0.0923(Ra)^{0.302}$ ($2{\times}10^4< Ra<2{\times}10^7$).

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.3
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• pp.259-264
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• 2014

Retrograde peri-implantitis (RPI) is defined as a clinically symptomatic periapical lesion. RPI is generally accompanied by symptoms of pain, tenderness, swelling and fistula. Several etiologic factors of RPI were possible, residual bacteria would be the main cause of RPI. Various treatment modalities have been introduced: debridement only or a combination of debridement with the grafting material accompanied by a detoxification of the infected implant surfaces, apicoectomy and so on. Although the definitive management methods remain undefined, many favorable clinical results of a treatment of RPI have been published. This case report introduces the 7-year long-term clinical result of the application the principle: implant surface detoxification using saline and chlorhexidine and guided bone regeneration with bone graft material and barrier membrane. If the implant was not mobile, it would be possible to treat RPI according to surgical approach and good results will be maintained over long term.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.726-729
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• 2010

Copper Pillar Tin Bump (CPTB) was investigated for high density chip interconnect technology development, which was prepared by electroplating and electro-less plating methods. Copper pillar tin bumps that have $100{\mu}m$ pitch were introduced with fabrication process using a KM-1250 dry film photoresist (DFR), with copper electroplating for Copper Pillar Bump (CPB) formation firstly, and then tin electro-less plating on it for control oxidation. Electric resistivity and mechanical shear strength measurements were introduced to characterize the oxidation effects and bonding process as a function of thermo-compression. Electrical resistivity increased with increasing oxidation thickness, and shear strength had maximum value with $330^{\circ}C$ and 500 N thermo-compression process. Through the simulation work, it was proved that when the CPTB decreased in its size, it was largely affected by the copper oxidation.

• Journal of Environmental Health Sciences
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• v.39 no.4
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• pp.360-368
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• 2013

Objectives: Phthalates are used in a large variety of products including as coatings of pharmaceutical tablets, film formers, stabilizers, dispersants, emulsifying agents, and suspending agents. They have been the subject of great public concern in recent years. The extensive uses of this material have attracted attention and issues regarding its safety have been raised. Methods: In this study, three types of phthalate skin permeation were studied using matrixes such as ointments, creams and lotions in vitro. The absorption of phthalate diesters [Dimethyl phthalate (DMP), Di-n-propyl phthalate (DPP) and Di-n-pentyl phthalate (DNPP)] using film former has been measured in vitro through rat skin. Epidermal membranes were set up in Franz diffusion cells and their permeability to PBS measured in order to establish the integrity of the skin before the phthalates were applied to the epidermal surface. Results: Absorption rates for each phthalate ester were determined and permeability assessment made to quantify any irreversible alterations in barrier function due to contact with the esters. Types of phthalate in vitro experimental results quickly appeared in the following order DMP > DPP ${\geq}$ DNPP. Conclusions: In the experimental results, lotion> cream> ointment, and the permeation rate of lotion with a great amount of moisture was the fastest. Skin permeation rate is generally influenced by the chemical characteristics of a given chemical, such as molecular weight and lipophilicity. As the esters became more lipophilic and less hydrophilic, the rate of absorption decreased.

• Biomedical Science Letters
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• v.26 no.3
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• pp.157-163
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• 2020

Long-term exposure to environmental pollutants can impair the human skin's barrier function and promote skin aging mechanisms. The visible consequences of these effects are dryness, wrinkles, black spots and worsening skin sensitivity. As awareness of the effects of environmental stressors on the skin has recently increased, consumers' demand for cosmetics that can provide anti-pollution effects is increasing. In this study, the possibility of anti-pollution cosmetic material was investigated by measuring the inhibitory effect of free radicals using a mixture of Nypa fruticans Wurmb (NF), Saussurea neoserrata (SN), Codium fragile (CF) and Enteromorpha compressa (EC), which has anti-inflammatory and antioxidant effects against irritation caused by dust. Combining the experimental results of a mixture of NF, SN, CF and EC by induction of fine dust stimulation, inhibition of inflammatory factors (PGE₂) and intracellular free radicals (ROS) by inhibiting effects were significant, indicating the possibility of use as anti-pollution cosmetics. The most plants used as sources of anti-pollution cosmetic ingredients contain antioxidants as active substances. In our highly industrialized and chemically polluted world, it is not surprising that most plants used as sources of anti-pollution cosmetic ingredients contain antioxidants as active substances. Considering our results, it can be suggested that this anti-pollutant consisting of NF, SN, CF and EC may be a good ingredient for skincare products for the cosmetic industry due to their antioxidant properties, which may especially alter skin aging.