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排序方式: 共有5013条查询结果,搜索用时 31 毫秒
951.
Seong Kyun Chung Ji Yeon Seo Jung Hoon Lim Hyung Hwan Park Myeong Jai Yea Hyun Jin Park 《Journal of food science》2013,78(5):E709-E714
Microcapsules containing thyme oil were prepared by in situ polymerization, using melamine–formaldehyde prepolymer as a wall material and 3 different emulsifiers (pluronic F‐127, tween 80, and sodium lauryl sulfate [SLS]). The general characteristics and release behavior of microcapsules, and their repellent effect against insects were investigated. The morphology of microcapsules using SLS was spherical shape with smooth surface. Microcapsules began to degrade at 150 °C. The particle size ranged from 1 to 10 μm and the loading efficiency of thyme oil was clearly affected by the emulsifier type. The highest loading efficiency appeared in microcapsules using SLS, which have good thermal resistance and smooth surface. The release rate of thyme oil from microcapsules was not only dependent on the storage temperature but also emulsifier type and microcapsules showed the sustained release properties for a long time. Diets, which were mixed with encapsulated thyme oil, expressed high insect repellent efficacy over 90% for 4 wk. Practical Application : Essential oil has various pest‐control characteristics, including repellent, ovicidal, and antifeedant efficacy. This work showed the sustained release properties and long‐lasting repellency of encapsulated essential oil. The results suggest that the great potential of essential oil microcapsules can be applied in coating or printing of food packaging materials for the insects repelling effects. 相似文献
952.
Mi Kwon Son Kyung Hee Jung Sang-Won Hong Hee-Seung LeeHong-Mei Zheng Myung-Joo ChoiJu Hyeon Seo Jun-Kyu SuhSoon-Sun Hong 《Food chemistry》2013
Pulsatilla koreana has been used as a traditional medicine for the treatment of several diseases. The purpose of this study was to determine if SB365, Pulsatilla saponin D isolated from the root of P. koreana inhibits the progression of colon cancer. We found that SB365 strongly suppressed the growth and proliferation of colon cancer cells and induced their apoptosis. Also, SB365 showed anti-angiogenic activity by decreasing the expression of HIF-1α and VEGF. These results were confirmed by an in vivo study showing that SB365 significantly inhibited tumor growth by the induction of apoptosis and inhibition of angiogenesis with stronger anticancer activity than 5-FU. When further examined for its anticancer mechanism, SB365 effectively suppressed the AKT/mTOR pathway both in vitro and in vivo. Taken together, our study demonstrated that SB365 inhibits the AKT/mTOR pathway, leading to the suppression of tumor growth and angiogenesis together with induction of apoptosis. Therefore, SB365 is a good candidate as a natural product for use in the treatment of colon cancer. 相似文献
953.
Comparative studies on major nutritional components of black waxy rice with giant embryos and its rice bran 总被引:1,自引:0,他引:1
Kim Jun Young Seo Woo Duck Park Dong-Soo Jang Ki Chang Choi Kyung-Jin Kim Sang-Yeol Oh Seong-Hwan Ra Ji-Eun Yi Gihwan Park Soo-Kwon Hwang Un-Ha Song You-Chun Park Bo-Ram Park Mi-Jin Kang Hang-Won Nam Min-Hee Han Sang-Ik 《Food science and biotechnology》2013,22(1):121-128
The concentration of nutrients in brown rice is mainly associated with embryo size. Various beneficial components have been purified from rice bran. Recently developed black waxy rice with a giant embryo (‘Milyang 263’, BGE), which is the ge t mutant of the GE gene, was selected and analyzed to produce high quality nutritional components. γ-Aminobutyric acid (GABA) content in BGE rice bran, one of the most important nutritional compounds in rice, showed a 10.6-fold increase (2.66±0.48 mg/g) compared to that of BGE brown rice (0.25±0.01 mg/g). In addition, brown rice and BGE rice bran showed enriched amylopectin (94.5±0.5 and 97.0±0.0%) and bioactive anthocyanin [Cy-3-G: 75.15±4.18 (brown rice), 82.97±0.81 (rice bran) and Pn-3-G: 1.52±0.50 (brown rice), 4.33±0.20 (rice bran); mg/100 g] contents. These results suggest that BGE rice bran can be used as an excellent raw material to efficiently produce high quality essential amino acids, cyanidin-3 glycoside-enriched anthocyanins, and GABA. 相似文献
954.
Sung Keun Jung Tae-Gyu Lim Sang Gwon Seo Hyong Joo Lee Young-Sun Hwang Myoung-Gun Choung Ki Won Lee 《Food science and biotechnology》2013,22(2):507-513
Cyanidin-3-O-(2″-xylosyl)-glucoside (C-3-O-(2″-xylosyl)-G) was analyzed as an active constituent from the fruit of Siberian ginseng (Acanthopanax senticosus) using a HPLC diode array detection-electrospray ionization/mass spectrometry analysis system and the effect of C-3-O-(2″-xylosyl)-G on UVB-induced inflammatory signaling in JB6 P+ cells was investigated. C-3-O-(2″-xylosyl)-G inhibited UVB-induced cyclooxygenase (COX)-2 expression and promoter binding activity in JB6 P+ cells and JB6 P+ cells stably transfected with the COX-2 luciferase reporter plasmid. It inhibited both the UVB-induced activator protein-1 (AP-1) and nuclear factor (NF)-κB transactivation in JB6 P+ cells stably transfected with the AP-1 and NF-κB luciferase reporter plasmids. Additionally, C-3-O-(2″-xylosyl)-G significantly suppressed UVB-induced upregulated phosphorylation of c-Jun N terminal kinase, MEK/extracellular signaling kinase, and mitogen activated protein kinase kinase (MAPKK) 3/6 in JB6 P+ cells. These results indicate that C-3-O-(2″-xylosyl)-G may be a promising chemopreventive material that acts by suppressing COX-2 expression and AP-1 and NF-κB transactivation and JNK, MAPKK3/6, and MEK/ERK1/2 phosphorylation. 相似文献
955.
A precise estimation and compensation of sampling frequency offset (SFO) is an important issue in an orthogonal frequency division multiplexing (OFDM) system because of its time-variant behavior. This paper considers the problem of SFO estimation for OFDM-based digital radio mondiale (DRM) systems. In this study, we develop expressions for the mean square error (MSE) of the conventional SFO estimators used in the OFDM-based DRM system. Their low-complexity variants and computation complexity are reported. The theoretical MSE analysis for different algorithms are validated by Monte-Carlo simulations within the framework of the OFDM parameter and pilot pattern defined in the DRM specification. It is also shown that the computation complexity of the low-complexity variants is significantly reduced, compared with that of original versions. 相似文献
956.
Sung-Chul Seo Sergey A. Grinshpun Yulia Iossifova Detlef Schmechel Carol Y. Rao Tiina Reponen 《Aerosol science and technology》2013,47(8):794-803
A field-compatible collection system was developed and tested for the collection and analysis of fungal fragments. The new collection system consists of two types of Sharp-Cut cyclone samplers (PM 2.5 and PM 1.0 ) and an after-filter. Fungal particles are collected into three size fractions: (1) spores ( > 2.5 μ m); (2) a fragment-spore mixture (1.0–2.5 μ m); and (3) submicrometer-sized fragments ( < 1.0 μ m). The system was laboratory-tested using polystyrene latex (PSL) particles and particulate matter aerosolized from sporulating Aspergillus versicolor and Stachybotrys chartarum cultures. In addition to the particle count measured with direct-reading instruments, the (1 → 3)- β -D-glucan content in each size fraction was determined with the Limulus Amebocyte Lysate (LAL) assay. Experiments conducted with PSL particles showed that the 50% cut-off values of the two cyclone samplers under the test conditions were 2.25 μ m and 1.05 μ m, respectively. No particle bounce onto the after-filter was observed when the total particle number entering the collection system was kept below 1.6 × 10 8 . The (1 → 3)- β -D-glucan assay of samples aerosolized from both fungal species suggested that surface area is an important factor for determining the (1 → 3)- β -D-glucan content in the entire size-range of particles. In conclusion, the new methodology is a promising tool for separating and analyzing fungal fragment samples. 相似文献
957.
Donglei Wei Beiling Yuan Yanlin Huang Taiju Tsuboi Hyo Jin Seo 《Journal of the American Ceramic Society》2013,96(7):2167-2171
Sm3+‐doped glass 13SrO–2Bi2O3–5K2O–80B2O3 was fabricated by the conventional melt‐quenching technique. The glass‐ceramics were obtained by heating the as‐prepared glasses in air atmosphere at selected temperatures 550°C, 600°C, 615°C, and 650°C, respectively. The luminescence spectra of both Sm3+ and Sm2+ were detected in the ceramic heated at 650°C where crystalline phase is formed. The as‐prepared glass and the ceramics heated at 550°C, 600°C, and 615°C show only the emission due to Sm3+. In the sample heated at 650°C in air atmosphere, however, part of Sm3+ ions was converted to Sm2+, giving rise to sharp emission lines which are characteristic of Sm2+ in crystalline state. It is suggested that Sm2+ ions are located at Sr2+ site in the ceramic while Sm3+ ions are located at Bi3+ sites. The Sm2+‐doped glass‐ceramic has a high optical stability because the fluorescence intensity decreases by only about 8% of its initial value upon excitation at 488 nm Ar+ laser. 相似文献
958.
An oscillator(OSC)with a metamaterial resonator based on high-Q is designed to improve the phase noise in Kband.The proposed metamaterial resonator is a lattice structure resonator(LSR)that is designed to be high-Q by a strong coupling of E-field at the resonance frequency.Thus the output of OSC is about 12.5dBm at the f0.The phase noise is 109.477dBc/Hz at 100kHz offset frequency. 相似文献
959.
Tip gap flow and aerodynamic loss generation in a turbine cascade equipped with suction-side winglets 总被引:4,自引:0,他引:4
The tip gap flow and aerodynamic loss generation over a plane tip equipped with a “constant-width suction-side” (CWSS) winglet and a “varying-width suction-side” (VWSS) winglet have been investigated in a turbine cascade. For a fixed tip gap of h/c = 2.0%, three different winglet widths of w/p = 5.28, 10.55, and 15.83% are tested for the CWSS winglet. The VWSS winglet is designed based on flow visualization and has almost the same winglet area as the CWSS winglet of w/p = 15.83%. In general, the suction-side winglets have a role to increase aerodynamic loss in the tip leakage vortex region but reduce aerodynamic loss in the passage vortex region. For the CWSS winglet, the total-pressure loss coefficient mass-averaged all over the measurement plane has no appreciable changes with increasing w/p from 0.0 to 10.55%, but tends to decrease with further increment of w/p. The VWSS winglet performs better in reducing aerodynamic loss in the passage vortex region than the CWSS winglet of w/p = 15.83% but leads to a little bit higher aerodynamic loss in the tip leakage vortex region. The aerodynamic loss reduction by the VWSS winglet is 7.4% in comparison with the plane tip without winglet, and is about 60% lower than that by the widest CWSS winglet. 相似文献
960.
Doyoung Chang Jeongryul Kim Dongkyu Choi Kyu-Jin Cho TaeWon Seo Jongwon Kim 《Journal of Mechanical Science and Technology》2013,27(1):207-214
Legged locomotion has been widely researched due to its effectiveness in overcoming uneven terrains. Due to previous efforts there has been much progress in achieving dynamic gait stability and as the next step, mimicking the high speed and efficiency observed in animals has become a research interest. The main barrier in developing such a robotic platform is the limitation in the power efficiency of the actuator: the use of pneumatic actuators produce sufficient power but are heavy and big; electronic motors can be compact but are disadvantageous in producing sudden impact from stall which is required for high speed legged locomotion. As a new attempt in this paper we suggest a new leg design for a mobile robot which uses the slider-crank mechanism to convert the continuous motor rotation into piston motion which is used to impact the ground. We believe this new mechanism will have advantage over conventional leg mechanism designs using electronic motors since it uses the continuous motion of the motor instead of sudden rotation movements from stall state which is not ideal to draw out maximum working condition from an electronic motor. In order to control impact timing from the periodic motion of the piston a mechanical passive clutch trigger mechanism was developed. Dynamic analysis was performed to determine the optimal position for the mechanical switch position of the clutch trigger mechanism, and the results were verified through simulation and experiment. Development of a legged locomotion with two degrees of freedom, slider-crank mechanism for impact and additional actuation for swing motion, is proposed for future work. 相似文献