Enhancement of the cytotoxicities and antioxidative activities of white ginseng extract by hydrolysis under mild acidic conditions

White ginseng extract (WGE) was hydrolyzed with organic acids to increase the yield of ginsenoside Rg₃ which has high bio-functional activities. The condition of hydrolysis by citric acid was studied to maximize a production of ginsenoside Rg₃. The total content of ginsenoside Rg₃ in WGE treated with 10% citric acid at 110°C for 1 h was 10-folds greater than that of commercial extract. The antitumor and antioxidant activities of WGE and the acid-hydrolysates were evaluated via an MTT assay and the DPPH method, respectively. At 1.0 mg/mL, hydrolysates inhibited the proliferation of AGS and Hep-2 cells by more than 90%, but did not inhibit their growth. It suggests that citric acid hydrolysis enhances the content of Rg₃. In addition, the acid hydrolysates evidenced a free radical scavenging activity of 80% at a concentration of 4.0 mg/mL, while WGE exhibited only a 49% free radical scavenging activity at the same concentration.     

Leaky mode directional coupler for prism coupling interconnection

A leaky mode directional coupler was fabricated with its beam shaped into a Gaussian-like profile and was experimentally demonstrated for suppressing the diffraction of an out-coupled beam. The demonstrated coupler consists of a multilayered waveguide with six layers that are embedded in a symmetric slab waveguide. The out-coupled beam profile was measured to be shaped into a Gaussian function by using the prism coupling method. There was an excellent agreement between the measured and theoretically predicted coupling angles, and it was also confirmed that the diffraction was suppressed.     

Lysophosphatidic Acid Mediates Imiquimod-Induced Psoriasis-like Symptoms by Promoting Keratinocyte Proliferation through LPAR1/ROCK2/PI3K/AKT Signaling Pathway

Psoriasis is a chronic inflammatory skin disease. Recently, lysophosphatidic acid (LPA)/LPAR5 signaling has been reported to be involved in both NLRP3 inflammasome activation in macrophages and keratinocyte activation to produce inflammatory cytokines, contributing to psoriasis pathogenesis. However, the effect and molecular mechanisms of LPA/LPAR signaling in keratinocyte proliferation in psoriasis remain unclear. In this study, we investigated the effects of LPAR1/3 inhibition on imiquimod (IMQ)-induced psoriasis-like mice. Treatment with the LPAR1/3 antagonist, ki16425, alleviated skin symptoms in IMQ-induced psoriasis-like mouse models and decreased keratinocyte proliferation in the lesion. It also decreased LPA-induced cell proliferation and cell cycle progression via increased cyclin A2, cyclin D1, cyclin-dependent kinase (CDK)2, and CDK4 expression and decreased p27^Kip1 expression in HaCaT cells. LPAR1 knockdown in HaCaT cells reduced LPA-induced proliferation, suppressed cyclin A2 and CDK2 expression, and restored p27^Kip1 expression. LPA increased Rho-associated protein kinase 2 (ROCK2) expression and PI3K/AKT activation; moreover, the pharmacological inhibition of ROCK2 and PI3K/AKT signaling suppressed LPA-induced cell cycle progression. In conclusion, we demonstrated that LPAR1/3 antagonist alleviates IMQ-induced psoriasis-like symptoms in mice, and in particular, LPAR1 signaling is involved in cell cycle progression via ROCK2/PI3K/AKT pathways in keratinocytes.     

Hypocholesterolemic effect of quercetin-rich onion peel extract in C57BL/6J mice fed with high cholesterol diet

Food Science and Biotechnology - Onion peel (OP) extract is known as a rich source of flavonoids, mainly quercetin. We hypothesized that OP has hypocholesterolemic effects. To investigate the...     

An Efficient Multicast Routing Protocol in Wireless Mobile Networks

Providing multicast service to mobile hosts in wireless mobile networking environments is difficult due to frequent changes of mobile host location and group membership. If a conventional multicast routing protocol is used in wireless mobile networks, several problems may be experienced since existing multicast routing protocols assume static hosts when they construct the multicast delivery tree. To overcome the problems, several multicast routing protocols for mobile hosts have been proposed. Although the protocols solve several problems inherent in multicast routing proposals for static hosts, they still have problems such as non-optimal delivery path, datagram duplication, overheads resulting from frequent reconstruction of a multicast tree, etc. In this paper, we summarize these problems of multicast routing protocols and propose an efficient multicast routing protocol based on IEFT mobile IP in wireless mobile networks. The proposed protocol introduces a multicast agent, where a mobile host receives a tunneled multicast datagram from a multicast agent located in a network close to it or directly from the multicast router in the current network. While receiving a tunneled multicast datagram from a remote multicast agent, the local multicast agent may start multicast join process, which makes the multicast delivery route optimal. The proposed protocol reduces data delivery path length and decreases the amount of duplicate copies of multicast datagrams. We examined and compared the performance of the proposed protocol and existing protocols by simulation under various environments and we got an improved performance over the existing proposals.     

Modeling the effect of γ-irradiation on reducing total bacterial populations in <Emphasis Type="Italic">gochujang</Emphasis> intended for consumption by astronauts in space programs

This study modeled the effect of γ-irradiation on reducing bacterial populations in space gochujang (Korean red pepper paste). The gochujang samples were γ-irradiated at 0, 5, 10, 15, and 20 kGy, and stored under accelerated storage condition (35°C for 10 days). During storage, total bacterial populations in gochujang samples were enumerated on plate count agar (PCA) on day 0, 1, 3, 5, 7, and 10. To calculate maximum specific growth rate (μ_max; log CFU/g/day), lag phase duration (day), low asymptote (Y ₀; log CFU/g), upper asymptote (Y _max; log CFU/g), and surviving cell counts recovered with PCA were fitted to the Baranyi equation. The parameters then were further expressed as a function of irradiation dose. Total bacterial populations in gochujang were decreased to below detection limit (1 log CFU/g) after irradiation (5–20 kGy). The samples irradiated at 5, 10, and 15 kGy then had bacterial cell recovery, but no growth was observed in 20 kGy irradiated samples during accelerated storage. After validation of models, acceptable model performances (B factor=1.15, A factor=1.29, RMSE=1.044, R ²=0.862) were observed. These results indicate that the developed models may be useful in predicting irradiation doses to produce space gochujang.     

Combined effects of heating and γ-irradiation on the microbiological and sensory characteristics of Gochujang (Korean fermented red pepper paste) sauce during storage

This study was conducted to evaluate the combined effect of heating and γ-irradiation on the microbiological and sensory characteristics of gochujang sauce. Gochujang sauces could be sterilized by heating (HT: 121°C for 15 min) or γ-irradiation (IR: 30 kGy), but their sensory qualities were severely decreased. Otherwise, the combined treatment of heat and γ-irradiation could minimize the change of sensory qualities. Combination treatment of γ-irradiation at 17.5 kGy after heating at 100°C for 30 min (HT-IR) would be optimal. During storage the gochujang sauce samples then were analyzed to enumerate total bacterial populations, to measure pH, and Hunter’s color values, and for sensory evaluation. Any growth of total bacterial populations was not observed in HT, IR, and HT-IR (detection limited 1< log CFU/g). The pH values of gochujang sauce ranged from 4.57 to 4.75 during storage. The Hunter’s (L*, a*, and b*) values of gochujang sauce were gradually decreased during storage, regardless of treatment. Sensory characteristics and acceptance of HT and IR were significantly lower (p<0.05) than those of non-treated control and HT-IR, but there was no difference (p⩾0.05) among non-treated control and HT-IR.