Strategies for managing the insufficiency of the proximal landing zone during endovascular thoracic aortic repair

Background The insufficiency of the proximal landing zone (PLZ) is a frequent factor challenging the applicability and efficacy of endovascular repair (EVR) for thoracic aortic disorders. This study discusses two strategies for conquering this challenge.Methods Ten patients underwent EVR for thoracic aortic diseases during a one-year period ending June 30, 2004. Nine patients had DeBakey type Ⅲ dissecting aortic aneurysm (DAA), and one had descending thoracic aortic aneurysm (DTAA). The PLZ, defined as the distance from the origin of the left subclavian artery (LSA) to the primary entry tear of the dissection or to the proximal aspect of DTAA, was less than 15 mm in all instances. EVR with intentional coverage of the LSA without any supportive bypass was employed in 6 patients with DAA, and the preliminary right-left carotid and left carotid-subclavian bypass combined with EVR in the DTAA and other 3 DAA cases. Results Technical success was achieved in all the patients. The patient with DTAA died from hemispheric cerebral infarction and subsequent multiple system organ failure following an uneventful recovery from the cervical reconstruction performed 1 week previously. In cases receiving the EVR with intentional coverage of the LSA, in two patients dizziness occurred, which noticeably resolved after intravenous administration of mannitol for 4 to 5 days, and a drop in blood pressure of the left arm was noted in all the cases, but remained clinically silent. No neurological deficits or limb ischaemia developed perioperatively or during the followup, ranging from 3 to 12 months, and complete thrombosis of the thoracic aortic false lumen was revealed on CT at 3 months in the 9 patients with DAA.Conclusions Both the intentional bypass absent coverage of the LSA and the adjunctive surgical bypass appear to be feasible and effective in managing the insufficiency of the PLZ during the endovascular thoracic aortic repair.

Management with the insufficient proximal landing zone for endovascular repair in aortic dissection

Background Sufficient length of the proximal landing zone （PLZ） is the key for a successful thoracic endovascular aortic repair （TEVAR） of an aortic lesion. The aim of this research was to investigate the safety, feasibility, efficacy, and problems of endovascular repair for aortic dissection with insufficient PLZ.Methods The clinical data between August 2005 and February 2010 from patients with insufficient PLZ for endovascular repair of aortic dissection were retrospectively reviewed. According to the classification proposed by Ishimaru, aortic zone 0 was involved in 3 cases, zone 1 in 10 cases, and zone 2 in 11 cases. A hybrid surgical procedure of supraortic debranching and revascularization, directly coverage the orifice of left subclavian artery, or a left common carotid artery chimney graft technique were performed to obtain an adequate proximal aortic landing zone.Results There was no significant difference in risk factors and diameter of the PLZ between Zone 0, Zone 1, and Zone 2. But the length of the PLZ was significantly different in the three groups （P 〈0.01）. There was no significant difference in technical and clinical success rate between the groups.Conclusions The procedure for extending an insufficient PLZ for endovascular repair for aortic arch pathology is feasible and relatively safe. The applicability of TEVAR in such aortic disorders may be expanded.

The ecological cost of land reclamation and its enlightenment to coast sustainable development in the northwestern Bohai Bay,China

Land has been widely reclaimed in large area in coastal zones all over the world to relieve the pressure of land shortage,promoting social development and economic growth.Asia has become a focus of land reclamation with the rapid industrialization and urbanization.From the Binhai New Area of Tianjin to the Caofeidian New Area of Tangshan,the undergoing project of land reclamation on the northwest coast of Bohai Bay,China,is the largest in the world.To clarify the environmental issues and benefit sustainable development of the coastal zone,we conducted both retrospective and predictive assessments of the ecological cost caused by land reclamation on the northwest coast of Bohai Bay,China.We calculated the ecological costs of ten aspects of the four ecosystem services,i.e.,supply,regulation,support and culture,with the monetary estimate approach.The results indicate that the ecological cost of the new land reclamation is US$971.9 million from 2000 to 2010 and that the cost will be US$702.1 million from 2010 to 2020.The costs of gas regulation and marine food supply account for the greatest parts of the total value.Suggestions for land reclamation oriented to sustainable development in the study area are put forward,including a rational planning based on the comprehensive evaluation,reducing the amount of land reclamation area,optimizing the structure of the reclaimed land,reclaiming land with the concept of ＂low impact development＂ and implementing ecological compensation mechanisms,etc.

Development and Prospect of Zoning Mode in the Three Rounds of Overall Land Use Planning of China

Zoning system is the basic mode of establishment of overall land use planning. In this study,the zoning mode and practice in the three rounds of overall land use planning that have been carried out in China were analyzed and summarized firstly,and then some obvious problems existing in the implementation of the zoning mode were analyzed. Finally,countermeasures and suggestions were put forward to provide necessary reference for further development and improvement of the zoning mode and the development of overall land use planning at all levels in China.

THE FEATURE AND EVALUATION OF ECOTONE IN CHINA

Based on explicating the definition of ecotone, this paper discussed emphatically the distribution and features of joint zone between land and water, transition zone between mountains and plains, and intersection zone between agricultural and animal husbandry regions. The geographic environment of the three ecotones were evaluated, their developing tendency predicted and the corresponding measures to be taken in the 21st century pointed out.

Dual-objective pattern optimization method for land suitability zoning in mountain counties

As the basic administrative unit of China,counties have grown rapidly in recent years in the context of rapid urbanization,especially for counties located in mountainous areas.The drastic changes in land in mountainous areas can easily cause irreversible damage to the sensitive ecological environment.Through the dual-objective suitability zoning of ecological and construction balance,regional sustainable land use patterns can be realized.In this study,Hantai District in Southern Shaanxi province,China,was chosen as the research area aiming at creating a balance between ecological supply and the development of construction in spatial planning.A dual-objective process evaluation system for ecological protection and construction development was proposed with 15 resistance factors selected from three attributes:natural ecology,economic society,and policy.The minimum resistance surface discrimination methods for ecological land and construction development land were proposed based on vertical space superposition and horizontal minimum cumulative resistance models.Finally,the land in Hantai District was divided into four development grades from the optimal angle of dual goals,i.e.,the construction core zone being 134.56 km^(2),the suitable construction zone 115.77 km2,the ecological buffer zone 153.74 km^(2),and the ecological control zone 151.93 km^(2),using the method combining resistance difference and threshold division.In addition,the development direction of each town under jurisdiction was identified.This study compensates for the deficiency of traditional methods that evaluate land only from a single vertical or horizontal process.

Soil Health and Sustainable Land Resource Management Practices at Municipal Level: A Case from Bheri Nagarpalika (Municipality), Jajorkot District, Nepal

The increasing challenges of pressure and ever-growing demands on limited resources in Nepal by diverse actors,land degradation,biodiversity loss and climate change require the rational use of land resources to sustain and enhance productivity and maintain resilient ecosystems for achieving the sustainable and efficient use of resources,taking into account biophysical and socioeconomic dimensions.Regarding this,Nepal Government has realized and taken initiation of scientific and sustainable land use zoning following the National Land Use Act 2019(2076 B.S.)to use land resources in practicable and sustainable manner.Using spatial information techniques such asZ-3 satellite image,remote sensing(RS),global positioning system(GPS)and geographic information system(GIS).Multicriteria decision making(MCDM)methods for acquiring spatial/temporal data,through expert judgment techniques based on field observation as well as laboratory analysis result,it was found that the soil nutrient status of,the municipality varied spatially and has pH with very high acidic to slightly alkaline but most of the soils are slightly acidic(39.58%).Majority of the soil are loam and sandy loam type with very low to high level of organic matter.Most of the municipal area is under medium range of organic matter.Nitrogen content ranges from very low to very high level as to same ranges of phosphorous(37.69%).Potassium level is also in very high to low as 37 percent land area has high level of potassium.Reclamation of acidic soil mainly in leachable soil is recommended with the proper management of Nitrogen with addition of organic matter is needed to manage for improving crop production.

近30年来洞里萨湖沿岸土地覆被变化及其对水位的响应

The transboundary influence of environmental change is a critical issue in the Lancang-Mekong region.As the largest river-connected lake in the lower Mekong,the ecological change and influence of Tonle Sap Lake have received widespread attention and discussion,especially after 2008,when the hydrological regime of the Lancang-Mekong River mainstream underwent distinct changes.However,the linkage and coupling mechanism between the lake riparian environment and mainstream water level change are still unclear.In this study,the interannual spatiotemporal changes in land cover in the Tonle Sap Lake riparian zone(TSLRZ)and their relationship with mainstream water levels were analysed.The results showed that the expansion of farmland was the most notable change in 1988–2020.After 2008,the land cover changes intensified,manifested as accelerated farmland expansion,intensified woodland fragmentation and significant water body shrinkage.Furthermore,the responses of the water body,degraded land,wasteland and grassland areas to the mainstream water levels weakened after 2008.Evidently,the land cover changes in the TSLRZ in the last 30 years were less related to the mainstream water level change than to local reclamation and logging.These results can offer a new scientific basis for the transboundary influence analysis of hydrological change.

1Chinese human geography and its contributions

The aim of this paper is to sift through examples of outstanding contributions made by Chinese human geography in terms of social applications and explain the basic concepts and theoretical methods explored by human geography that are behind the applications of results with major social influence, so as to be able to summarize the main school that represents developments in contemporary Chinese human geography. Chinese human geography upholds the subject＇s designation as being integrated and interdisciplinary. Research focuses on interactions between the natural and human spheres of the Earth＇s surface, and it is guided by the understanding and effects of the processes of regional sustainable development at different spatial scales. Chinese human geography has innovatively established the following development paradigm： ＂To be guided by application requirements, refine key issues of the discipline in the course of solving major issues of human geography in national and regional development, and by solving those key issues, to enhance its ability to provide scientific and technological support to serve national and local needs while promoting its own development.＂ Results from early Chinese human geography studies on land use and agricultural zoning, recent research results on point-axis system models and T-shaped national spatial development patterns, and current research results on territorial function theory and major function oriented zones have all continued and strengthened the mainstream school of Chinese human geography and have avoided the global tendency for human geography to become rapidly human-oriented, while results have been applied at the highest level of decision-making management. Chinese human geography can provide lessons for developing countries and may play a leading role in the future development of global human geography.

A Historical Analysis on the Public Transport Development in Shanghai's Concessions

Set in modern Shanghai's concessions, this paper reviews and identifies the evolution of public transport in Shanghai's concessions from such perspectives as the distribution of public transport lines, the growth of passenger volume, and traffic management. Then, by using quantitative analysis and superposing related statistical data with historical maps, it analyzes the relationship between the density of the public transport network and the land price zoning. The paper concludes that public transport has great influences on the modernization of urban space and public life in modern Shanghai.