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一种新型Ka波段三节3 dB Wilkinson耦合器
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作者 刘源 王婕 《科学技术与工程》 2008年第19期5389-5393,共5页
根据多节3dBWilkinson耦合器的经典设计方法,针对Ka波段遇到的问题,提出了使用90°圆弧线替代半圆形分支臂,设计了一种Ka波段三节3dBWilkinson等功率耦合器,有效地解决了分支臂间的去耦合问题。仿真结果表明,在26.5—40GHz,插入损... 根据多节3dBWilkinson耦合器的经典设计方法,针对Ka波段遇到的问题,提出了使用90°圆弧线替代半圆形分支臂,设计了一种Ka波段三节3dBWilkinson等功率耦合器,有效地解决了分支臂间的去耦合问题。仿真结果表明,在26.5—40GHz,插入损耗约为0.5dB,所有端口的回波损耗>13dB(VSWR小于1.65),输出端口隔离度>13dB,较好地满足了Ka波段HMIC功率分配与合成电路的需求。 展开更多
关键词 功率分配器 毫米波 多节3 DB Wilkinson耦合器 混合MIC
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Omega-3 fatty acids for the treatment of non-alcoholic fatty liver disease 被引量:5
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作者 Matteo Nicola Dario Di Minno Anna Russolillo +3 位作者 Roberta Lupoli Pasquale Ambrosino Alessandro Di Minno Giovanni Tarantino 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第41期5839-5847,共9页
Non-alcoholic fatty liver disease (NAFLD) has been recognized as a major health burden. It is the most important cause of chronic liver disease and a major in- dependent cardiovascular risk factor. Lacking a definit... Non-alcoholic fatty liver disease (NAFLD) has been recognized as a major health burden. It is the most important cause of chronic liver disease and a major in- dependent cardiovascular risk factor. Lacking a definite treatment for NAFLD, a specific diet and an increase in physical activity represent the most commonly used therapeutic approaches. In this review, major literature data about the use of omega-3 polyunsaturated fatty ac- ids (n-3 PUFAs) as a potential treatment of NAFLD have been described, n-3 PUFAs, besides having a beneficial impact on most of the cardio-metabolic risk factors (hy- pertension, hyperlipidemia, endothelial dysfunction and atherosclerosis) by regulating gene transcription factors [i.e., peroxisome proliferator-activated receptor (PPAR) cz, PPARy, sterol regulatory element-binding protein-i, carbohydrate responsive element-binding protein], im- pacts both lipid metabolism and on insulin sensitivity. In addition to an enhancement of hepatic beta oxidation and a decrease of the endogenous lipid production, n-3 PUFAs are able to determine a significant reduction of the expression of pro-inflammatory molecules (tumor necrosis factor-~ and interleukin-6) and of oxygen reac- tive species. Further strengthening the results of the in vitro studies, both animal models and human interven- tion trials, showed a beneficial effect of n-3 PUFAs on the severity of NAFLD as expressed by laboratory pa- rameters and imaging measurements. Despite available results provided encouraging data about the efficacy of n-3 PUFAs as a treatment of NAFLD in humans, well- designed randomized controlled trials of adequate size and duration, with histological endpoints, are needed to assess the long-term safety and efficacy of PUFA, as well as other therapies, for the treatment of NAFLD and non-alcoholic steatohepatitis patients. It is worthwhile to consider that n-3 PUFAs cannot be synthesized by the human body and must be derived from exogenous sources (fish oil, flaxseeds, olive oil) which are typical foods of the Mediterranean diet, known for its beneficial effects in preventing obesity, diabetes and, in turn, cardiovascular events. According to these data, it is important to consider that most of the beneficial effects of n-3 PUFAs can also be obtained by an equilibrate nutrition program. 展开更多
关键词 Hepatic steatosis Non-alcoholic fatty liverdisease Omega-3 polyunsaturated fatty acids Animalmodels
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Morphometric, Reproductive Parameters and Seasonal Variations in Fatty Acid Composition of the Mantis Shrimp Squilla mantis (Crustacea: Stomatopoda) in the Gulf of Gabes (Tunisia) 被引量:2
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作者 Sami Mili Nawzet Bouriga +1 位作者 Hechmi Missaoui Othman Jarboui 《Journal of Life Sciences》 2011年第12期1058-1071,共14页
The growth, reproductive properties and the variations in total lipids and fatty acids in the gonads and muscle tissue of the mantis shrimp Squilla mantis (Crustacea: Stomatopoda) caught from the gulf of Gabes in T... The growth, reproductive properties and the variations in total lipids and fatty acids in the gonads and muscle tissue of the mantis shrimp Squilla mantis (Crustacea: Stomatopoda) caught from the gulf of Gabes in Tunisia were studied by sampling carried out between Jan. 2005 and Dec. 2006 to elucidate the importance of these components during sexual maturation. A total of 16,569 specimens were examined. The sex of this species was determined macroscopically and the proportion of females (47.07%) was significantly lower than that of males (52.93%) with a ratio of 1 :l. 12 (male^female). The mean total lengths (TL) of the male and female individuals were 142.02 ~: 22.76 mm and 141.45 + 24.37 mm, respectively. Length-weight (TL-W) relationship was estimated as W = 7 ~ l06 TL3 o644 for females and W = 4 ~ 10"6 TL320o7 for males, being altometrically positive for both sexes. The reproductive season, evaluated from the gonado-somatic index (GS1), extended from Dec. to July, with a peak in Feb.. The smallest mature female was 93 mm total length. Fifty percent of the females were mature at 147.19 mm total length. The levels of lipid displayed pronounced seasonal fluctuations with the highest value in Feb. and the lowest value in Oct.. Major fatty acids in both gonads and muscle tissue (female and male) were C 14:0, C 16:0, C 18:0, C 18: I n-9, C 18:2n-6, C 18:3n-3, C20:4n-6, C20:5n-3 and C22:6n-3. Significant increases in the levels of saturated and poly-unsaturated fatty acids were observed in gonads. The levels of n-3 poly-unsaturated fatty acids (PUFA), particularly C20:5n-3, decreased in gonads as ovarian development proceeded. Docosahexaenoic acid (DHA), linoleic acid (LA) and eicosapentaenoic acid (EPA) were the most abundant polyunsaturated fatty acids (PUFAs) in the muscle tissue for both male and female. The highest percentages for EPA and DHA were found in winter and summer season for Squilla mantis in the Gulf of Gabes. The n-3/n-6 ratio fatty acids ratio in Squilla mantis can be significantly influenced by spawning and season. It was conchtded that the mantis shrimp is a healthy item in the human diet during the winter and summer period when balanced n-3/n-6 ratios and EPA and DHA levels are considered. 展开更多
关键词 Squilla mantis mantis shrimp growth reproduction fatty acid Gulf of Gabes
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