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171.
Ashley L. Kiemen André Forjaz Ricardo Sousa Kyu Sang Han Ralph H. Hruban Laura D. Wood PeiHsun Wu Denis Wirtz 《Advanced Materials Technologies》2024,9(6):2301837
Pancreatic ductal adenocarcinoma (PDAC) is a deadly cancer that can develop from pancreatic intraepithelial neoplasia (PanIN), a microscopic lesion in the pancreatic ductal system. PanIN and PDAC are conventionally studied in 2D via histological tissue sections. As such, their true structure is poorly understood due to the inability to image them in 3D. CODA, a recently developed technique for reconstruction of tissues at cellular resolution, is used to study the 3D morphology of the pancreas. Here, CODA is extended through 3D printing of normal pancreatic ducts, PanIN, and PDAC at cm-scale and µm resolution. A methodology is presented to create 3D printable files from anatomical maps generated from serial histological images and to show detailed validation of the accuracy of this method. Existing 3D printing workflows utilizing medical images derived from computerized tomography (CT), X-ray, and magnetic resonance imaging (MRI) are scientifically proven to be useful in printing whole organ-scale structures with sub-mm resolution. Here, using serial histological sections, it is demonstrated that 3D printing of higher-resolution structures is also possible. Finally, with the 3D models of normal ducts, PanIN, and PDAC, marked changes to the structure of the human pancreas during tumorigenesis are revealed. 相似文献
172.
Asantewa Tenkorang Mark Yeboah-Agyepong Richard Buamah Nelson W. Agbo Rabia Chaudhry Ashley Murray 《国际水》2013,38(7):831-842
Several of the 10 key challenges targeted by the African Water Vision 2025 are directly or indirectly related to human waste management, in particular strengthening the financial base for providing adequate sanitation services. This case study describes a novel approach to improving the operation and maintenance of a waste stabilization pond system in Ghana by turning it into a dual-purpose wastewater treatment plant and commercial fish farm. Results of a collaborative pilot study between private, public and academic partners to test the institutional and technical feasibility of the model as well as the public health impacts are presented. 相似文献
173.
Over the past century, flow regulation and vegetation encroachment have reduced active channel widths along the central Platte River, Nebraska. During the last two decades, an annual program of in‐channel vegetation management has been implemented to stabilize or expand active channel widths. Vegetation management practices are intended to enhance riverine habitats which include nocturnal roosting habitat for sandhill cranes. Evaluating the success of other management treatments such as streamflow modification requires an understanding of how flow shapes the sandbars in the river and how sandbar morphology interacts with flow to create crane habitat. These linkages were investigated along a 1‐km managed river reach by comparing the spatial pattern of riverine roosts and emergent sandbars identified with aerial infrared imagery to variables computed with a two‐dimensional hydraulic model. Nocturnal observations made multiple years showed that the area and patterns of riverine roosts and emergent sandbars and the densities of cranes within roosts changed with stage. Despite sandbar vegetation management, low flows were concentrated into incised channels rather than spread out over broad sandbars. The flow model was used to compute hydraulic variables for identical streamflows through two sandbar morphologies; one following a period of relatively high flow and the other following the low‐flow period. Compared with the simulation using the morphology from the antecedent high flow, the simulation using the morphology from the antecedent low flow produced a smaller quantity of available wetted area. These remote‐sensing observations and hydraulic simulations illustrate the importance of considering flow history when designing streamflows to manage in‐channel habitat for cranes. Published in 2008 by John Wiley & Sons, Ltd. 相似文献
174.
Carlos N. A. Salinas Rodriguez Richard Ashley Berry Gersonius Jeroen Rijke Assela Pathirana Chris Zevenbergen 《Wiley Interdisciplinary Reviews: Water》2014,1(2):173-186
The water sensitive city is a term within urban water management in which the concept of resilience to extreme climatic events and climate change plays a key role and represents the interaction between different branches of water science, engineering, and other domains such as urban planning and design. In this context, resilience is the ability of a system to cope with or recover from inter alia floods and droughts and also to retain original identity in some form in the face of long‐term change. It is generally accepted that sustainable systems with respect to water management are mainly dominated by their resilience, which is intrinsic to water sensitive cities, and includes social, economic, and environmental as well as technical systems, such as built infrastructure and environments, and their interactions. Therefore, each system cannot be considered in isolation but needs to be seen as a part of wider aspects of water and urban services and utilities in resilient cities. New urban development can be better provided with flood and drought resilience because of the opportunity for the implementation of the available technical, social, and economic knowledge. This is different in the case of existing urban areas where maximization of the value and use of water requires more and in‐depth analysis. The growing movement for water‐sensitive urban design (WSUD), a concept developed in Australia, provides inspiration for maximizing the value and use of water in urban areas, with an increasing consideration of flood and drought resilience. Synergistic integration between the extant knowledge on WSUD together with resilience approaches can lead to the establishment of a new model for water sensitive cities which are also flood resilient. Similarly, dealing with urban flooding in a wise manner can simultaneously optimize the use of all kinds of available resources—also enhancing resilience for droughts. This article is categorized under:
- Engineering Water > Planning Water
175.
R.M. Ashley J. Blanskby R. Newman B. Gersonius A. Poole G. Lindley S. Smith S. Ogden R. Nowell 《Journal of Flood Risk Management》2012,5(1):14-22
Flood risks are increasing and available funding is reducing, posing professionals with the need to change practices. ‘Active learning’ can help to develop the capacity to accept different perspectives on risk and performance and to use alternative innovatory responses. Breaking the entrapment of traditional approaches requires cultural change in the organisations and the individuals involved. Learning Alliances can help to do this. In Yorkshire (England), a common forum for learning and action in relation to flood and water management has evolved into Learning and Action Alliances (LAAs). These alliances, which are essential components of three European Union INTERREG IVB projects, have national, regional and local dimensions. Internationally, these and partner LAAs, are being utilised to engender transnational learning. Experience from the establishment and operation of these LAAs is presented and it is concluded that there is no single blueprint for an ideal LAA. Nor is their establishment and operation straightforward. 相似文献
176.
The breakover voltage of double-injection devices is calculated and is shown to be a constant at low thermal hole densities but a monotonically decreasing function of thermal holes at high densities. The results are applied to GaAs:Mn double-injection devices to explain their relatively low experimental breakover voltage. The radiant flux from the GaAs:Mn devices is measured and shown to exhibit a decreasing quantum efficiency with increasing current due to a carrier sweep out effect. 相似文献
177.
Recovery of most surface features in many parts of the Rotorua geothermal field (RGF) has continued as water levels rose and pressures increased following bore closures that began in 1986. However, the pattern of recovery of features is very variable, even within a relatively small area, with no apparent consistency as to location or type of feature. Most features in the Whakarewarewa Thermal Area that were affected by the pre-1986 pressure drawdown have recovered, but some have not. More puzzling is the behaviour of a few features (such as Waikorohihi and Mahanga geysers) that initially showed recovery, but later ceased activity. Chemical data indicate that for some features there has been an increase in the amounts of deep fluid reaching the surface, but in others there has been no change. Examination of seismic records suggests that the unusual behaviour is not related to local seismic activity. The recovery of many thermal features has been beneficial from a tourist and environmental viewpoint. However, there have been some detrimental occurrences. Following the decline and disappearance of thermal features before the bore closures, the vents of some features were inadvertently filled in and the land around them reclaimed and used for buildings or services. As water levels recovered after the closures, discharge to the surface recommenced, causing damage to buildings and associated services, resulting in several houses being damaged or forced to be relocated. In all cases, however, the discharges were from historically active vents. The data suggest that while most natural thermal features may recover from the effects of geothermal exploitation some may not, and in the case of Rotorua there does not appear to be any pattern or explanation for such non-recovery. 相似文献
178.
179.
Exploitation of the Rotorua geothermal system started in the 1920s, but during 1967–1986 the number of wells and mass withdrawal greatly increased. Natural surface activity waned in the 1970s, prompting public concern, which led to a monitoring programme (1982), enforced closures of many wells (1987), and punitive royalty charges (1987). During the well closure programme, mass withdrawal was reduced by about 60%. Within one year, water levels increased by 2 m and pressures by 0.02 MPa. Since then, levels and pressures have continued to rise gradually. Many surface thermal features have shown recovery: geysers have resumed stronger or longer duration eruptions, springs have recommenced or strengthened overflows, and the frequency of hydrothermal eruptions has decreased. Some failed geysers have not yet recovered, indicating recovery is slow or that the bore closure programme may not guarantee recovery of all surface features. 相似文献
180.
Large motor loads on long line services present several technical problems involving starting, operating, and protection of the facilities equipment. Where there are several large synchronous motors driving reciprocating compressors, problems tend to become more difficult and expensive to solve. One such facility is described and some aspects of the problems and their solutions are presented. The static var generator (SVG) is shown to have a strong effect on system stability. Analysis is presented by the authors for optimizing equipment and operating procedures at the company-owned 115-13.8 kV facilities. 相似文献