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91.
Objective To study the effect of cyclosporine A drug delivery system (CsA-DDS) on the prevention of posterior capsule opacification (PCO) after experimental intraocular lens implantation in rabbit eyes. Methods Twenty healthy New Zealand white rabbits, whose left eyes and right eyes were used respectively as experiment eyes and controls, were subjected to extracapsular lens extraction and artificial lens implantation. During the operation, CsA-DDS with poly (lactideco-glycolide) as carriers or empty DDS was implanted in the capsular bag for the experimental eyes and controls respectively. After the operation, anterior chamber reaction, intraocular pressure (IOP) and CsA concentration were monitored and twelve weeks after the operation, the eyes were extracted for histopathological and morphological examinations. Results There were no differences between the two groups in conjunctival congestion,IOP change and anterior chamber reaction. PCO was less severe in the experimental eyes than in the controls. Light microscopy revealed that posterior capsular membrane in the experimental eyes was slick, with no obvious proliferation,whereas in the controls, there were lens epithelial cell proliferation and cortex regeneration of different degrees.Morphological examination with electron microscope showed that in the experimental eyes, lens epithelial cells did not function actively and apoptosis occurred, whereas in the controls, epithelial cells presented active function. No marked ultrastructural changes were found in either group. Conclusion Cs-DDS can inhibit PCO after intraocular lens implantation in rabbit eyes and does not have toxic effects on the surrounding ocular tissues. Therefore, it has a good potential for clinical use in prevention of PCO. 相似文献
92.
93.
中国西部地区46个贫困县妇女孕产期保健现况 总被引：6，自引：0，他引：6
目的 了解西部地区妇女保健现状 ,分析其影响因素 ,从而寻找适当的改进措施。方法 对 9个项目省、自治区和直辖市的 4 6个项目县 ,进行了横断面调查设计及分层多阶段随机抽样调查。结果 产前检查率平均在 86 %以上 ;产前检查地点主要以乡卫生院为主 (占 4 7.78% ) ;分娩地点 :住院分娩的占 4 8.5 0 % ,在家里的占 4 9.2 6 %。结论 进一步提高住院分娩率 ,提高乡级卫生人员的业务素质 ,加强妇女保健的宣传工作 ,将有助于改善西部贫困地区的妇女保健状况 相似文献
94.
地铁车辆回送方法的研究 总被引：2，自引：0，他引：2
制动系统是城市轨道交通车辆的关键系统之一,其工作可靠性直接关系到列车的运行安全。回送试验是保证地铁车辆安全押运的重要环节,本文阐述了地铁车辆各个制动系统的回送工作原理、回送管路铺设和连接方法,并总结了地铁车辆在回送试验和押运过程中的注意事项。 相似文献
95.
ABSTRACTThe Mega-ships, the maximum containerships represented by 20,000TEU-class (LOA:400m, Breadth: 60m, Draft: 16m) which are able to transit both the Malacca Strait and the Suez Canal, have emerged in 2013, aiming at lower shipping cost by economy of scale. At the same time, they inevitably increased port calls in a rotation to collect more cargo demand, resulting in the longer transit time than ever before. Taking this trend into account, the authors proposed the quick delivery scenario between East Asia and Northwest Europe by the NSR (Northern Sea Route)/SCR (Suez Canal Route)-combined shipping, of which 4,000 TEU ice-class containership transits the NSR during the summer season and the SCR in the wintertime, based on a year-round scheduled operation. The quick delivery scenario gives the shorter transit time at an affordable shipping cost depending on the NSR navigable season length. However, the quick delivery scenario cannot avoid uncertainties in navigation especially via the NSR in the summer season, due to rough weather, sea ice, low visibility and icing in the icy water section of the NSR. The authors preliminarily concluded that a year-round scheduled operation of the NSR/SCR-combined shipping will be secured, if the practical navigation schedule is appropriately prepared. 相似文献
96.
《Maritime Policy and Management》2012,39(8):982-994
ABSTRACTThis study empirically evaluated the effects of unmanned aerial vehicles (UAVs) applications and acceptable cost on intention to use UAVs in maritime shipping contexts. Factor analysis was employed to identify key UAVs applications (i.e. pollution forensics, supervision and service, search and rescue, humanitarian and emergency delivery, and safety and security), acceptable UAV cost, and intention to use UAVs. Survey data were collected from 201 respondents working for a maritime port corporation, shipping company, agency, and stevedoring company, and then hierarchical regression analysis was conducted to test research hypotheses and examine the effects of UAVs applications and acceptable cost dimensions on intention to use UAVs. The results suggested that the pollution forensics, supervision and service, search and rescue, humanitarian and emergency delivery, and safety and security dimensions positively affected intention to use UAVs. The study findings also revealed negative associations among seniority, turnover, and intention to use UAVs. Theoretical contributions and managerial implications are proposed to assist maritime port bureaus, corporations, and operating practice design in remaining competitive and efficient. 相似文献
97.
This paper examines network design where OD demand is not known a priori, but is the subject of responses in household or user itinerary choices to infrastructure improvements. Using simple examples, we show that falsely assuming that household itineraries are not elastic can result in a lack in understanding of certain phenomena; e.g., increasing traffic even without increasing economic activity due to relaxing of space–time prism constraints, or worsening of utility despite infrastructure investments in cases where household objectives may conflict. An activity-based network design problem is proposed using the location routing problem (LRP) as inspiration. The bilevel formulation includes an upper level network design and shortest path problem while the lower level includes a set of disaggregate household itinerary optimization problems, posed as household activity pattern problem (HAPP) (or in the case with location choice, as generalized HAPP) models. As a bilevel problem with an NP-hard lower level problem, there is no algorithm for solving the model exactly. Simple numerical examples show optimality gaps of as much as 5% for a decomposition heuristic algorithm derived from the LRP. A large numerical case study based on Southern California data and setting suggest that even if infrastructure investments do not result in major changes in link investment decisions compared to a conventional model, the results provide much higher resolution temporal OD information to a decision maker. Whereas a conventional model would output the best set of links to invest given an assumed OD matrix, the proposed model can output the same best set of links, the same daily OD matrix, and a detailed temporal distribution of activity participation and travel from which changes in peak period OD patterns can be observed. 相似文献
98.
Several industry leaders and governmental agencies are currently investigating the use of Unmanned Aerial Vehicles (UAVs), or ‘drones’ as commonly known, for an ever-growing number of applications from blue light services to parcel delivery. For the specific case of the delivery sector, drones can alleviate road space usage and also lead to reductions in CO2 and air pollution emissions, compared to traditional diesel-powered vehicles. However, due to their unconventional acoustic characteristics and operational manoeuvres, it is uncertain how communities will respond to drone operations. Noise has been suggested as a major barrier to public acceptance of drone operations in urban areas. In this paper, a series of audio-visual scenarios were created to investigate the effects of drone noise on the reported loudness, annoyance and pleasantness of seven different types of urban soundscapes. In soundscapes highly impacted by road traffic noise, the presence of drone noise lead to small changes in the perceived loudness, annoyance and pleasantness. In soundscapes with reduced road traffic noise, the participants reported a significantly higher perceived loudness and annoyance and a lower pleasantness with the presence of the same drone noise. For instance, the reported annoyance increased from 2.3 ± 0.8 (without drone noise) to 6.8 ± 0.3 (with drone noise), in an 11-point scale (0-not at all, 10-extremely). Based on these results, the concentration of drone operations along flight paths through busy roads might aid in the mitigation of the overall community noise impact caused by drones. 相似文献
99.
The retail route design problem extends the capacitated vehicle routing problem with time windows by introducing several operational constraints, including order loading and delivery restrictions (last-in, first-out), order-dependent vehicle capacity, material handling limits at the warehouse, backhauling, and driving time bounds. In this paper, the problem is modeled on a directed network for an application associated with a major grocery chain. Because the corresponding mixed-integer program proved too difficult to solve with commercial software for real instances, we developed a greedy randomized adaptive search procedure (GRASP) augmented with tabu search to provide solutions. Testing was done using data sets provided Kroger, the largest grocery chain in the US, and benchmarked against a previously developed column generation algorithm. The results showed that cost reductions of $4887 per day or 5.58% per day on average, compared to Kroger’s corresponding solutions. 相似文献
100.
The purpose of this paper to present a cooperative scheduling algorithm for solving the Dynamic Pickup and Delivery Problem with Time Windows (DPDPTW). The idea behind cooperative waiting strategies is to calculate simultaneously the waiting times for all nodes in the solution. Classical non‐cooperative scheduling algorithms perform the scheduling for each route independently of the scheduling of the other routes. We present the Cooperative Scheduling Problem (CSP) based on the elliptical areas generated by vehicles waiting at their nodes. The CSP is solved by means of a genetic algorithm and is evaluated by using a set of benchmarks based on real‐life data found in the literature. Initially, two waiting strategies are presented: Wait‐Early‐Time scheduling and Balanced‐Departure scheduling. Extensive empirical simulations have been carried out by analyzing the degree of dynamism and the average waiting time, a new concept defined to take into account the gap between the time windows of pickup and delivery nodes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献