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91.
Wenchao Chen Zhengzhong Jing Kek Foo Chin Baokun Qiao Yan Zhao Lin Yan Choon‐Hong Tan Zhiyong Jiang 《Advanced Synthesis \u0026amp; Catalysis》2014,356(6):1292-1300
The first asymmetric conjugate addition of mercaptans to β‐substituted‐β‐trifluoromethyl oxazolidinone enoates has been developed. The opposite enantiomers of adducts, containing a trifluoromethylated hetero‐quaternary stereogenic centers, could be obtained by utilizing two pseudo‐enantiomeric Cinchona alkaloid‐derived tertiary amine/squaramides as catalysts. Potassium dihydrogen phosphate was found to accelerate the reaction rate without compromising the enantioselective excess. A variety of chiral trifluoromethylated tertiary thioethers and thiols were readily prepared with excellent enantioselectivity.
92.
V. Senthilkumar ;Le C. Tam ;Yong Soo Kim ;Yumin Sim ;Maeng-Je Seong ;Joon. I. Jang 《Nano Research》2014,(12):1759-1768
There has been growing research interest in the use of molybdenum disulfide in the fields of optoelectronics and energy harvesting devices, by virtue of its indirect-to-direct band gap tunability. However, obtaining large area thin films of MoS2 for future device applications still remains a challenge. In the present study, the amounts of the precursors (S and MOO3) were varied systematically in order to optimize the growth of highly crystalline and large area MoS2 layers by the chemical vapor deposition method. Careful control of the amounts of precursors was found to the key factor in the synthesis of large area highly crystalline flakes. The thickness of the layers was confirmed by Raman spectroscopy and atomic force microscopy. The optical properties and chemical composition were studied by photoluminescence (PL) and X-ray photoelectron spectroscopy. The emergence of strong direct excitonic emissions at 1.82 eV (A-exciton, with a normalized PL intensity of -55 × 10^3) and 1.98 eV (B-exciton, with a normalized PL intensity of -5 × 10^3) of the sample at room temperature clearly indicates the high luminescence quantum efficiency. The mobility of the films was found to be 0.09 cm^2/(V.s) at room temperature. This study provides a method for the controlled synthesis of high-quality two-dimensional (2D) transition metal dichalcogenide materials, useful for applications in nanodevices, optoelectronics and solar energv conversion. 相似文献
93.
94.
Quasi-isotropic bending responses of metallic sandwich plates with bi-directionally corrugated cores
In order to reduce anisotropic behaviors of sandwich plates with open channel cores under the bending load, bi-directionally corrugated cores were introduced. Bi-directionally corrugated core has two additional design parameters related with a corrugation pass than uni-directionally corrugated core, so that its properties with respect to core orientations can be controlled. Sandwich plate with bi-directionally corrugated core is designed optimally so that beam buckling of face sheets is reduced drastically and anisotropic buckling behavior in the face sheets is minimized. The cores fabricated by a sectional forming process were bonded with face sheets by adhesive bonding. Three-point bending experiments were carried out with respect to core orientations. It has been shown from the experiments that sandwich plates with bi-directionally corrugated cores exhibit quasi-isotopic bending behaviors and structural performances in sandwich plates. 相似文献
95.
96.
Utilisation possibility of Enterococcus faecalis isolates from neonate's faeces for production of fermented sausages as starter cultures 下载免费PDF全文
Hoa Van Ba Hyun‐Woo Seo Soo‐Hyun Cho Yoon‐Seok Kim Jin‐Hyoung Kim Beom‐Young Park Hyun‐Wook Kim Jun‐Sang Ham Pil‐Nam Seong 《International Journal of Food Science & Technology》2017,52(7):1660-1669
This study aimed at assessing the utilisation possibility of Enterococcus faecalis as starter cultures for production of fermented sausages. The E. faecalis isolates isolated from faeces samples of 5‐day‐old healthy newborn babies, identified by 16SrDNA sequencing and free from virulence determinants as proven by genomic sequencing, were used for fermented sausages production as starter culture. Six treatments (four inoculated with four different E. faecalis isolates, one with commercial starter culture and one control) were prepared. The inoculation with E. faecalis showed a stronger acidification compared with the control. The treatments with E. faecalis showed significantly higher flavour and acceptability scores in comparison with the control or commercial starter culture. Both of commercial starter culture and E. faecalis were positive with tyramine. Apart from the amine production, the inoculation with E. faecalis generally improved the acidifying activity and flavour of the products, suggesting their application potentials in fermented sausages production as starter cultures. 相似文献
97.
Eun-Jeong Jeong Nam Keun Lee Jisun Oh Seong Eun Jang Jai-Sung Lee In-Hyu Bae Hyun Hee Oh Hoo Kil Jung Yong-Seob Jeong 《Food science and biotechnology》2014,23(4):1193-1198
The antifungal effects of essential oils (EOs) on cultures of the known cheese fungal contaminants Penicillium spp. were evaluated. Cinnamon leaf and bark EOs were the most effective among 8 EOs tested. The main components of both cinnamon EOs were eugenol, cinnamaldehyde, and linalool. Both inhibited growth of Penicillium spp. at a concentration of 10% v/v (2,000 ppm/mm2) on a lawn cell plate. When tested using 3 commercially available cheese starters, cinnamon EOs showed no effect against the FD-DVS ABT-5 cheese starter. However, growth of lactobacilli was inhibited in the presence of ≥10% (v/v) of leaf and bark EOs for the KAZU 1 starter, and ≥5% (v/v) for the FD-DVS FLORA-DANICA starter. A concentration of 4,000 ppm/mm2 of cinnamon EOs completely inhibited growth of the Penicillium spp. that naturally contaminates the surface of Appenzeller cheese. 相似文献
98.
Development of a microbial time-temperature integrator system using lactic acid bacteria 总被引:1,自引:0,他引:1
Seong Hwan Lim Woo Yeong Choe Byung Hyun Son KwangWon Hong 《Food science and biotechnology》2014,23(2):483-487
A microbial time-temperature integrator (TTI) system was developed using lactic acid bacteria (Weissella koreensis) obtained from baechukimchi. Activation energy (Ea), which represents the temperature dependence of the TTI response, was calculated using the Arrhenius equation. Ea values for the color change (ΔE value), maximum specific growth rate (μmax), and pH change of the TTI measured under different isothermal conditions (5, 10, 15 and 20°C) were 99.88, 95.91, and 93.38 kJ/mol, respectively. According to the time taken to reach the TTI endpoint by the initial inoculum level of W. koreensis (6.2, 5.5, 4.5, and 3.4 log CFU/mL), a negative correlation was observed in 63.5, 101.8, 115.1 and 166.6 h. In addition, initial bacterial counts decreased significantly up to almost 4% at 20°C in 3 months when W. koreensis viability was measured at the freezing point of the microbial TTI system (20 and ?80°C) for 1 week, 1 month, 2 months, and 3 months. However, viability was about 95% at 80°C. This microbial TTI system would be useful to monitor the quality of food with similar Ea values during storage or distribution. 相似文献
99.
Song Hee Moon Mi Chang Hae Young Kim Hae Choon Chang 《Food science and biotechnology》2014,23(2):489-497
Yeasts were isolated from over-ripened kimchi and identified. Isolates were identified as Pichia kudriavzevii, Kazachstania servazii, Kazachstania exigua, Kazachstania bulderi, and Rhodotorula mucilaginosa. Among the isolates, P. kudriavzevii GY1 and K. bulderi HY2 were separately inoculated into kimchi and incubated at 10°C for 21 days. After incubation, HY2 kimchi showed less offodors, whereas GY1 kimchi showed strong off- and moldyodors in the sensory evaluation. P. kudriavzevii GY1 showed significantly higher polygalacturonase activity than K. bulderi HY2. Volatile compounds in kimchi samples were analyzed by HSPM-GC. Peak areas of obnoxiousodor compounds, including methanethiol, were 6.61, 9.46, and 20.87% for control kimchi, HY2 kimchi, and GY1 kimchi, respectively. Therefore, P. kudriavzevii was mainly responsible for kimchi spoilage, including off-odors and texture softening. Moreover, K. bulderi was associated with kimchi deterioration at cell counts up to 8.0–9.0 log CFU/mL, even though its effects were not as strong as those of P. kudriavzevii. 相似文献
100.
The anti-inflammatory effects of Acanthopanax senticosus leaves (ASL) and the effects of extrusion were evaluated. ASL exhibited in vitro and in vivo antiinflammatory activities in experimental systems. Extrusion increased the effect of ASL. ASL reduced C48/80-induced histamine release from HMC-1 cells as well as in vivo model, suggesting that ASL induces mast cell stabilization and has an anti-histamine activity. The effects of ASL and extruded ASL (ASLE) on pro-inflammatory cytokine production were evaluated. ASL treatment reduced MCP- 1, TNF-α, and IL-1β mRNA expressions and decreased their protein levels in HMC-1 cells. Decreases in serum NO, MDA, and TNF-α levels were observed in acute inflammatory rats, and extrusion increased the effects of ASL in a dose-dependent manner. These data support pharmacological basis of ASL and the effect of extrusion for future treatment of inflammation. 相似文献