73 research outputs found
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Alternate methods of supplying the Oregon coast with construction aggregates
Impending shortages of high-quality aggregates in areas along the Oregon coast have forced users to search for new sources of supply. A number of feasible methods exist for supplying the affected areas. Three of these alternatives are: (1) importation, either by truck, rail, or barge; (2) the use of good-quality dredged rock; or (3) the use of abundant supplies of lowÂ-quality or marginal aggregates, including low-quality dredged materials comÂbined with admixtures to improve performance.
This report evaluates these alternatives in terms of energy, economics, and environmental consequences. Advantages and disadvantages of each method and cost comparisons are included as an aid to planning and decision making
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Construction aggregates available along the Oregon coast
The natural reserves of high quality construction aggregates found along the Oregon coast are being depleted. The impending shortages are compounded by restrictions being placed on existing aggregate sources because of energy. economic, and environmental considerations, and zoning regulations. A curÂrent solution for the shortage is to import quality aggregate from areas that have more abundant reserves, such as the Willamette Valley. Figure 1 shows the amounts of aggregate imported to the Oregon coast from various sources, usually by truck. As this practice is both costly and energy-intensive, alternative sources of aggregate must be identified. As abundant supplies of lower-quality aggregates can be found near the Oregon coast, one alternative is to use these lower-quality, or "marginal," aggregates for construction purposes, particularly for road building materials.
The purpose of this paper is to identify the general types and extent of aggregates available along the Oregon coast. An evaluation of the imporÂtant characteristics of the aggregates and the problems associated with their use in construction is also provided
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Upgrading marginal aggregates for road construction along the Oregon Coast
The task of obtaining good-quality aggregate for construction is a growÂing problem for most Oregon coastal communities. Current shortages have forced users to import quality aggregate from areas as far as the Willamette Valley. The practice of transporting aggregate over such long distances is both costÂly and energy-intensive.
One feasible solution to this problem is to use abundant local supplies of low-quality, "marginal" aggregates. However, engineers encounter numerous problems when they use marginal aggregates for construction. Characteristics of these aggregates that contribute to problems include low resistance to mechanical and chemical degradation and poor gradation. Although these materiÂals are not of sufficient quality for conventional use, special design conÂsiderations can help obtain satisfactory performance.
The term beneficiate is used to describe a process by which marginal aggregates are upgraded or otherwise made suitable for construction purposes. Marginal aggregates available along the Oregon coast and considered good candidates for beneficiation include: marine basalts, sandstones, sand, and dredged materials.
This report briefly outlines the problems associated with the use of these aggregates (a more thorough examination can be found in Construction Aggregates Available Along the Oregon Coast, Oregon State University Extension Service Special Report 614, hereafter Available). This report also includes a discussion of some of the more promising methods of beneficiating marginal aggregates and design considerations for their use
Mesenchymal Stem Cells Secrete Multiple Cytokines That Promote Angiogenesis and Have Contrasting Effects on Chemotaxis and Apoptosis
We have previously shown that mesenchymal stem cells (MSC) improve function upon integration in ischemic myocardium. We examined whether specific cytokines and growth factors produced by MSCs are able to affect angiogenesis, cellular migration and apoptosis. Conditioned media (CM) was prepared by culturing MSC for 48 hours. CM displayed significantly elevated levels of VEGF, Monocyte Chemoattractant Protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), MIP-1β and monokine induced by IFN-γ (MIG) compared to control media. MSC contained RNA for these factors as detected by RT-PCR. CM was able to induce angiogenesis in canine vascular endothelial cells. MCP-1 and MIP-1α increased cell migration of MSC while VEGF reduced it. H9c2 cells treated with CM under hypoxic conditions for 24 hours displayed a 16% reduction in caspase-3 activity compared to controls. PI 3-kinase γ inhibitor had no effect on controls but reversed the effect of CM on caspase-3 activity. MCP-1 alone mimicked the protective effect of CM while the PI 3-Kγ inhibitor did not reverse the effect of MCP-1. CM reduced phospho-BAD (Ser112) and phospho-Akt (Ser473) while increasing phospho-Akt (Thr308). MCP-1 reduced the level of phospho-Akt (Ser473) while having no effect on the other two; the PI 3-Kγ inhibitor did not alter the MCP-1 effect. ERK 1/2 phosphorylation was reduced in CM treated H9c2 cells, and inhibition of ERK 1/2 reduced the phosphorylation of Akt (Ser473), Akt (Thr308) and Bad (Ser112). In conclusion, MSC synthesize and secrete multiple paracrine factors that are able to affect MSC migration, promote angiogenesis and reduce apoptosis. While both MCP-1 and PI3-kinase are involved in the protective effect, they are independent of each other. It is likely that multiple pro-survival factors in addition to MCP-1 are secreted by MSC which act on divergent intracellular signaling pathways
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Understanding the influences on successful quality improvement in emergency general surgery: learning from the RCS Chole-QuIC project
Abstract: Background: Acute gallstone disease is the highest volume Emergency General Surgical presentation in the UK. Recent data indicate wide variations in the quality of care provided across the country, with national guidance for care delivery not implemented in most UK hospitals. Against this backdrop, the Royal College of Surgeons of England set up a 13-hospital quality improvement collaborative (Chole-QuIC) to support clinical teams to reduce time to surgery for patients with acute gallstone disease requiring emergency cholecystectomy. Methods: Prospective, mixed-methods process evaluation to answer the following: (1) how was the collaborative delivered by the faculty and received, understood and enacted by the participants; (2) what influenced teams’ ability to improve care for patients requiring emergency cholecystectomy? We collected and analysed a range of data including field notes, ethnographic observations of meetings, and project documentation. Analysis was based on the framework approach, informed by Normalisation Process Theory, and involved the creation of comparative case studies based on hospital performance during the project. Results: Chole-QuIC was delivered as planned and was well received and understood by participants. Four hospitals were identified as highly successful, based upon a substantial increase in the number of patients having surgery in line with national guidance. Conversely, four hospitals were identified as challenged, achieving no significant improvement. The comparative analysis indicate that six inter-related influences appeared most associated with improvement: (1) achieving clarity of purpose amongst site leads and key stakeholders; (2) capacity to lead and effective project support; (3) ideas to action; (4) learning from own and others’ experience; (5) creating additional capacity to do emergency cholecystectomies; and (6) coordinating/managing the patient pathway. Conclusion: Collaborative-based quality improvement is a viable strategy for emergency surgery but success requires the deployment of effective clinical strategies in conjunction with improvement strategies. In particular, achieving clarity of purpose about proposed changes amongst key stakeholders was a vital precursor to improvement, enabling the creation of additional surgical capacity and new pathways to be implemented effectively. Protected time, testing ideas, and the ability to learn quickly from data and experience were associated with greater impact within this cohort
Safety and Effectiveness of Meropenem in Infants With Suspected or Complicated Intra-abdominal Infections
Background. Intra-abdominal infections are common in young infants and lead to significant morbidity and mortality. Meropenem is a broad-spectrum antimicrobial with excellent activity against pathogens associated with intra-abdominal infections. The purpose of this study was to determine the safety and effectiveness of meropenem in young infants with suspected or complicated intra-abdominal infections
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