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661.
目的以自发性高血压大鼠(SHR)为研究对象,探讨动脉血管壁胶原成分、血管紧张素Ⅱ受体(ATR)AT1和AT2亚型蛋白表达的增龄性改变。方法幼年组(7周)、成年组(26周)、老年组(51周)雄性SHR各20只,正常饮食饲养1周后,测定鼠尾动脉收缩压;胸主动脉及肠系膜上动脉(SMA)取材后,石蜡切片,Mallory染色观察壁纤维化程度,免疫组化SABC法测定ATR蛋白表达。结果 3个年龄组SHR大鼠的血压随增龄呈现明显升高[(151±26)mmHg vs.(166±9.0)mmHg vs.(180±13)mmHg,P<0.05];胸主动脉和SMA壁Ⅰ型和Ⅲ型胶原纤维沉积亦随增龄增多(IA值:主动脉416±43 vs.483±74 vs.553±83,SMA 387±46 vs.425±67 vs.468±81,P均<0.05);胸主动脉和SMA壁AT1和AT2表达均随年龄增长呈增高趋势(灰度值:胸主动脉AT1 159±7.0 vs.150±8.7 vs.139±8.9,AT2 187±6.9 vs.181±9.5 vs.169±10;SMA AT1 163±11 vs.112±11 vs.128±18,AT2 188±11 vs.171±15 vs.171±13;P均<0.05),AT1/AT2比值仅在老龄组增高(幼龄及老龄组胸主动脉0.86±0.01 vs.0.78±0.08;SMA 0.85±0.07 vs.0.71±0.08,P均<0.05)。结论增龄可导致SHR成纤维细胞生长、胶原纤维沉积,血管壁局部AT1、AT2表达及二者比例改变,同时AT1由单纯的介导血管收缩作用转变为介导血管壁重塑,可能是SHR大鼠血压增龄性改变的机制之一。 相似文献
662.
L. P. Perera J. P. Carvalho C. Guedes Soares 《Journal of Marine Science and Technology》2011,16(1):84-99
This paper focuses on a fuzzy logic based intelligent decision making system that aims to improve the safety of marine vessels
by avoiding collision situations. It can be implemented in a decision support system of an oceangoing vessel or included in
the process of autonomous ocean navigation. Although Autonomous Guidance and Navigation (AGN) is meant to be an important
part of future ocean navigation due to the associated cost reduction and improved maritime safety, intelligent decision making
capabilities should be an integrated part of the future AGN system in order to improve autonomous ocean navigational facilities.
In this study, the collision avoidance of the Target vessel with respect to the vessel domain of the Own vessel has been analyzed
and input, and output fuzzy membership functions have been derived. The if–then rule based decision making process and the
integrated novel fuzzy inference system are formulated and implemented on the MATLAB software platform. Simulation results
are presented regarding several critical collision conditions where the Target vessel fails to take appropriate actions, as
the “Give way” vessel to avoid collision situations. In these situations, the Own vessel is able to take critical actions
to avoid collisions, even when being the “Stand on” vessel. Furthermore, all decision rules are formulated in accordance with
the International Maritime Organization Convention on the International Regulations for Preventing Collisions at Sea (COLREGs),
1972, to avoid conflicts that might occur during ocean navigation. 相似文献
663.
The use of spatial computable general equilibrium (SCGE) models for assessing the economic impacts of transport projects is one of the key items on the research agenda for project appraisal in the Netherlands. These models are particularly suitable for analysing indirect effects of transport projects through linkages between the transport sector and the wider economy. Potentially, according to the literature, indirect effects that are additional to first-order direct cost reductions can turn out to be up to almost 80% in magnitude of the direct impacts. Given the relevance of these models for policy appraisal, experiences with this new modelling approach are important to report. After two years of development and application of SCGE models for transport appraisal, we found that the translation of theory behind the spatial equilibrium models into practical model specifications and empirical applications is a challenging task, and may lead to problems in project appraisal in terms of inaccuracies in the assessment of impacts. This paper discusses some key challenges we encountered with the specification of the Dutch SCGE model RAEM. This chapter is especially useful for researchers developing SCGE applications for use in transport appraisal and those who want to get a better understanding of differences between theoretical and computable SCGE modelling. 相似文献
664.
665.
666.
Moira L. McConnell 《WMU Journal of Maritime Affairs》2011,10(2):127-141
This paper begins by providing a brief overview of the International Labour Organization’s Maritime Labour Convention, 2006 (MLC, 2006), noting that this Convention, often called the “Seafarers’ bill of rights”, seeks to achieve both social and labour rights (“decent work”) for seafarers and fair competition (achieving a level-playing field) for shipowners. It has been described as the “fourth pillar” of the international maritime regulatory regime complementing the major International Maritime Organization conventions. The paper provides a brief update on international efforts to achieve the 30/33 formula needed to bring the Convention into force [at present, the tonnage element, 33% has been achieved already with coverage now at 54% of the world fleet (by gross tonnage), with 18 ratifications]. It then explores challenges faced by flag States in connection with capacity to implement the ship inspection and certification system under the MLC, 2006 and other difficulties with respect to legal implementation by the flag States. The paper also comments on some challenges in connection with port State, coastal State and labour-supplying State responsibilities. The paper points out that the MLC, 2006 is a comprehensive code that covers diverse issues and a wider range of both ships and seafarers than previous conventions. It often requires interdepartmental cooperation to implement its requirements at the national level. The paper concludes that, despite the slower pace of ratification in some regions, largely because of the recent economic and other crises, it appears that many actors in the maritime sector are already actively engaged in MLC, 2006 implementation, often ahead of governments. The question is not “if” but “when” the formula will be achieved to allow the MLC, 2006 to enter into force. 相似文献
667.
668.
M. J. L. Boada B. L. Boada D. Garcia-Pozuelo V. Diaz 《International Journal of Automotive Technology》2011,12(6):821-829
The behaviour of the tyre plays an important role in the vehicle handling. An accurate tyre model that estimates these forces
and moments it is highly essential for the studies of vehicle behaviour. For the last ten years neural networks have attracted
a great deal of attention in vehicle dynamics and control. Neural networks have been effectively applied to model complex
systems due to their good learning capability. In this paper a recursive lazy learning method based on neural networks is
considered to model the tyre characteristics under combined braking and cornering. The proposed method is validated by comparison
with experimental obtained responses. Results show the estimated model correlates very well with the data obtained experimentally.
Moreover, the neural model proposed allows to include the asymetric tyre behaviour in the tyre model without difficulty. 相似文献
669.
为综合开发利用低价值贝类中的功能保健品成分,利用索氏/超声提取、尿素包合法提取了紫贻贝中的多烯脂肪酸乙酯,对提油后的残渣利用热水提取、离子交换层析富集的方法提取了其中的牛磺酸,利用高效液相色谱-二极管阵列检测器(HPLC-DAD)分析测定了产品中二十碳五烯酸乙酯(EPA-E)、二十二碳六烯酸乙酯(DHA-E)的含量,利用薄层色谱法、吸光光度法定性定量测定了产品中的牛磺酸,结果显示紫贻贝中含有相当量的多烯脂肪酸乙酯及牛磺酸成分,有望作为高价值功能保健食品的来源. 相似文献
670.
运用产业关联的基本理论,通过投入产出表的计算,对TOD模式下轨道交通产业与其他产业的直接关联系数、影响力系数及感应度系数进行分析,得出轨道交通产业的特点,同时对轨道交通产业与其他产业的技术经济联系进行分析,具有一定的参考价值。 相似文献