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531.
作者通过大鼠乌头碱中毒心肌线粒体 CCO 的超微结构定位,观察到乌头碱引起 CCO 的定位紊乱。由于损害程度不同,出现三种情况:(1)CCO 失去在线粒体嵴膜和内膜上的定位,酶反应产物呈自由扩散状态,酶反应强度对照组有所增强或相似;(2)CCO 失去在线粒体嵴膜和内膜上的定位,酶反应强度较对照组明显减弱;(3)在同一线粒体中部分保持 CCO 的嵴膜、内膜定位,部分失去 CCO 在嵴膜和内膜上的定位。实验结果表明,乌头碱干扰了心肌细胞呼吸链的电子传递,抑制氧化磷酸化的正常进行,导致心肌能量代谢障碍。 相似文献
532.
目的通过测定免疫正常人、β-内酰胺类药物过敏者以及非离子型造影剂过敏者血液中CD63、肥大细胞羧肽酶A3(MC-CPA3)、人末端补体复合物SC5b-9,探讨嗜碱性粒细胞活化试验(basophil activation test,BAT)在非离子型造影剂过敏反应中的诊断价值。方法采用流式细胞术测定全血中嗜碱性粒细胞CD63表达率。采用ELISA法测定血清中MC-CPA3、血浆中SC5b-9含量。结果非离子型造影剂和β-内酰胺类药物过敏者血液中嗜碱性粒细胞CD63表达率、MC-CPA3以及SC5b-9含量均较免疫正常人升高(P0.05)。结论非离子型造影剂过敏者血液中嗜碱性粒细胞和肥大细胞发生活化,补体系统的激活也参与了非离子型造影剂过敏反应的发生。流式细胞术分析BAT可作为非离子型造影剂过敏反应的诊断方法。 相似文献
533.
目的采用CT容积再现技术(CT volume rendering technique,CT-VRT)测量西南地区汉族人胸骨柄体和,建立其与身高的回归方程。方法 160例(男、女性各80例)西南地区汉族成年体检者通过CTVRT(重建层厚1 mm)分别测量胸骨柄长和体长,二者的代数和即为柄体和。同时测量受检者真实身高,分别建立男、女性柄体和与身高的回归方程。结果分别建立了男、女性胸骨柄体和(x3)与身高(y)之间关系的一元回归方程(男性:y=135.000+2.118 x3;女性:y=120.790+2.808 x3)。两方程均具有统计学意义(P0.05),且预测准确性均为100%。结论 CT-VRT能作为胸骨指标测量的有效方法。采用CT-VRT测量的胸骨柄体和能应用于西南地区汉族人身高推算。 相似文献
534.
Maíra Kerpel dos Santos PhD Alexander Acosta PhD Ryan Capote BS Bakhtawar Tabassam BS James Ley PhD Martin Quirke PhD José Almirall PhD 《Journal of forensic sciences》2023,68(4):1162-1177
The 4- Aminophenol (4-AP) colorimetric test is a fast, easy-to-use, and cost-effective presumptive assay of cannabis plant material producing different chromophores with THC-rich cannabis (blue color) and with CBD-rich cannabis (pink color). The main drawback of the 4-AP test is a brief observation window where the color rapidly changes to black, limiting the utility of the test. We now report for the first time, the identification of the product chromophores between 4-AP and CBD/THC as well as propose an explanation and a solution for the color degradation of the chromophores. The identification of the chromophores is provided by spectroscopic (UV–Vis), chromatography, and mass spectrometry (TLC and LC-QToF-MS). Oxidation of excess 4-AP (Reagent A) in the presence of NaOH (Reagent B) produces the black color observed for the previously reported 4-AP tests and reported in the literature. The adjustment of reactants concentrations and volumes of 4-AP:THC/CBD to a 1:1 ratio significantly reduces the black oxidation by-product and increases the observation window up to 2 h instead of the previously reported 5–10 min. For the first time, mass spectrometry and chromatography confirmed that the reaction of THC and CBD with 4-AP produced chromophores with m/z (M + H) = 420, consistent with proposed indophenol structures. The TLC method developed confirmed the separation between CBD and THC chromophores. The specificity of the test is also reported, showing false positive results for the presence of THC (blue color) for samples of thyme and oregano. LDA and SIMCA models showed that the optimized 4-AP procedure performs better than the previously reported 4-AP color test. 相似文献
535.
A frequent lament among researchers is that public policy makers should pay more attention to scientific and technical information (STI). If there is any single area where one might expect STI to be used in public policy making and agenda setting it is in science and technology policy. Many of the policy makers in science and technology policy are themselves scientists or researchers and presumably would prove especially receptive to STI. However, STI is only one of many types of information used in policy making and policy actors often differ in the extent to which they view STI as credible, particularly compared to other types of potentially policy‐relevant information. Research on credibility (the believability of information, information types, and media) has shown variance and policy makers’ “credibility maps.” Thus, some policy makers have preference for formal information generally and STI specifically, but others privilege raw data, personal experience, authority, history and anecdote, analogical reasoning, or conformance to ideology, to name just a few of the information choices. Here, we build on the current researchers’ previous bibliometrics‐based work and use data from 41 semi‐structured elite interviews with National Research Council (NRC) executives and staff and NRC committee members concerning the use of STI in reports issued by the NRC. Findings show that the use of STI in NRC reports varies according to the nature of the inquiry and the sponsor. Information used in the reports is based on not only the assessed credibility of information but also its perceived direct relevance and the availability of STI as compared to other types of information. In general, the amount of STI in the NRC reports tends to have modest effects on the likelihood that reports will be used in policy making or by the mass media. More important factors include the timing of the report with respect to political agendas, the party requesting the report, and the enacted roles of NRC staff members and committee chairs. 相似文献
536.
Policy termination is identified as a rare occurrence and thus difficult to study. However, one policy area, community water fluoridation, has seen an apparent increase in termination in recent years. We examine the specific case of termination in Calgary, Alberta in 2011 with a specific goal to apply Kingdon's Multiple Streams Approach to the policy termination framework. Our findings suggest that of key importance for the termination of water fluoridation was the impending need for an upgrade to the fluoridation infrastructure, the effectiveness of the local anti‐fluoridation activists, the speed of decision making, and a prominent framing of the issue in ethical terms. The opening of a policy window made possible by the 2010 Calgary municipal election, one that introduced a number of new members to council, as well as the presence of a policy entrepreneur who took advantage of the window's opening, were of specific importance to the success of policy termination. 相似文献
537.
Alex Ingrams 《政策研究评论》2019,36(3):357-377
Big data applications have been acclaimed as potentially transformative for the public sector. But, despite this acclaim, most theory of big data is narrowly focused around technocratic goals. The conceptual frameworks that situate big data within democratic governance systems recognizing the role of citizens are still missing. This paper explores the democratic governance impacts of big data in three policy areas using Robert Dahl’s dimensions of control and autonomy. Key impacts and potential tensions are highlighted. There is evidence of impacts on both dimensions, but the dimensions conflict as well as align in notable ways and focused policy efforts will be needed to find a balance. 相似文献
538.
This research examines the impact of increasing the stringency of renewable portfolio standards (RPS) on the consumption of energy produced from renewable sources. Putting prior findings in the context of policy learning, first we focus on technological innovation, factor endowments, and economic energy dependence of American states to track how RPS have proliferated and strengthened. Next, we look at the net effect of this RPS evolution on state fossil fuel energy divestment. To evaluate the interplay between: a) the political desire to lower fossil fuel use, b) technological feasibility to do so, and c) the economic trade‐offs and risks, we focus on the industrial sector dependence on energy security and affordability. Our results indicate that energy security is a priority and even in light of increasing RPS stringency, states with relatively weak but mandatory RPS are leaders in aggregate renewable energy consumption. This fact is due to favoring biofuel and hydro generation rather than solar and wind because of lower deployment costs. 相似文献
539.
Laurie E. Adkin 《政策研究评论》2019,36(5):603-634
Innovation is the central element of climate change policy in many jurisdictions. Reduced to technology development and linked to market‐driven priorities, innovation accommodates the interests of large emitters in the energy sector and underpins a sustainable development discourse that denies ecological limits to economic growth. This study examines the use of innovation as a key component of climate change policy in the case of Alberta's Climate Change Emissions Management Corporation, utilizing a political economy approach to explain the drivers of government funding priorities. An analysis of this technology fund's investments over nine years, under two different governments, revealed that nearly half of the revenue has been used to subsidize R&D in the fossil fuels industry in the name of clean energy development, and that this priority has continued despite recent government commitments under the Paris CoP agreement. The carbon levy system that generates revenue for the fund has been unsuccessful in incentivizing facility reductions, pointing to the need for more stringent regulation. Innovation as a framework for transition to a post‐carbon economy is severely limited by its exclusion of the roles of social knowledge and citizen participation in envisaging and designing paths for change. 相似文献
540.
Information controls are actions intended to deny, disrupt, monitor, or secure information for political ends. They can be implemented using a wide variety of technical and nontechnical means. Political contests over the control of information are heightened around important events, such as major anniversaries, armed conflicts, protests, and elections. In this paper, we offer a comparative case study of online censorship of the circumvention tool Psiphon during the Iranian elections in 2016 and 2013, drawing on unique access to analytics data from Psiphon. We find that the Iranian regime developed its censorship approach in two ways, deploying blocking that was more targeted and strategically timed in the more recent case. Evidence suggests that the regime relaxed censorship of Psiphon during the official campaign period for the 2016 election. The apparent objective of this new approach was to control access to information while minimizing the political consequences of doing so. 相似文献