36 research outputs found
Impact of recipient functional status on 1-year liver transplant outcomes
BACKGROUND: The Karnofsky Performance Status (KPS) scale has been widely validated for clinical practice for over 60 years.AIM: To examine the extent to which poor pre-transplant functional status, assessed using the KPS scale, is associated with increased risk of mortality and/or graft failure at 1-year post-transplantation.METHODS: This study included 38278 United States adults who underwent first, non-urgent, liver-only transplantation from 2005 to 2014 (Scientific Registry of Transplant Recipients). Functional impairment/disability was categorized as severe, moderate, or none/normal. Analyses were conducted using multivariable-adjusted Cox survival regression models.RESULTS: The median age was 56 years, 31% were women, median pre-transplant Model for End-Stage for Liver Disease score was 18. Functional impairment was present in 70%; one-quarter of the sample was severely disabled. After controlling for key recipient and donor factors, moderately and severely disabled patients had a 1-year mortality rate of 1.32 [confidence interval (CI): 1.21-1.44] and 1.73 (95%CI: 1.56-1.91) compared to patients with no impairment, respectively. Subjects with moderate and severe disability also had a multivariable-adjusted 1-year graft failure rate of 1.13 (CI: 1.02-1.24) and 1.16 (CI: 1.02-1.31), respectively.CONCLUSION: Pre-transplant functional status is a useful prognostic indicator for 1-year post-transplant patient and graft survival.</p
CPT-based axial capacity design method for driven piles in clay
There are clear advantages in the establishment of reliable, direct cone penetration test (CPT) based methods for assessment of the axial capacity of driven piles. These advantages motivated the formation of a joint industry project (JIP) under the management of the Norwegian Geotechnical Institute (NGI), which initially led to the creation of a unified database of high-quality pile load tests in sand and clay. The unified database has the consensus approval of representatives of the profession and personnel in multiple companies from the offshore energy sector. This paper presents a component of the research from the second phase of the JIP, which had the objective of developing a new CPT-based method for driven piles in clay to unify several CPT-based methods that are in use today. First, a rational basis for the CPT-based formulation is described, using trends from instrumented pile tests; the description facilitates an understanding of the approach and illustrates its empirical nature and limitations. The unified database was used to calibrate the formulation and it led to good predictions for an independent database of pile load tests and for measured distributions of shaft friction
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FABSYN: Floorplan-aware bus architecture synthesis
As system-on-chip (SoC) designs become more complex, it is becoming harder to design communication architectures to handle the ever increasing volumes of inter-component communication. Manual traversal of the vast communication design space to synthesize a communication architecture that meets performance requirements becomes infeasible. In this paper, we address this problem by proposing an automated approach for floorplan-aware bus architecture synthesis (FABSYN) to synthesize cost-effective, bus-based communication architectures that satisfy the performance constraints in a design. Our synthesis approach incorporates a high-level floorplanning and wire delay estimation engine to evaluate the feasibility of the synthesized bus architecture and detect bus cycle time violations early in the design flow, at the system level. We present case studies of network communication SoC subsystems for which we synthesized bus architectures, detected and eliminated timing violations, and generated core placements in a matter of hours instead of several days for a manual effort
Growth of single-walled carbon nanotubes on a Co–Mo–MgO supported catalyst by the CVD of methane in a fixed bed reactor: Model setting and parameter estimation
In this work methane was decomposed to hydrogen and carbon to determine its kinetic behavior during reaction over a Co–Mo–MgO supported catalyst using the CVD (Chemical Vapor Deposition) technique. Decomposition of methane molecules was performed in a continuous fixed bed reactor to obtain data to simulate methane decomposition in a gas phase heterogeneous media. The products and reactants of reaction were analyzed by molecular sieve column followed by GC-analysis of the fractions to determine the amount of product converted or reactant consumed. The synthesis of single-walled carbon nanotubes was performed at atmospheric pressure, different temperatures and reactant concentrations. The experimental data analyzed to suggest the formula for calculation of the initial specific reaction rate of the carbon nanotubes synthesis, were fitted by several mathematical models derived from different mechanisms based on Longmuir-hinshelwood expression. The suggested mechanism according to dissociation adsorption of methane seems to explain the catalytic performance in the range of operating conditions studied. The apparent activation energy for the growth of SWNTs was estimated according to Arrhenius equation. The as grown SWNTs products were characterized by SEM, TEM and Raman spectroscopy after purification. The catalyst deactivation was found to be dependent on the time, reaction temperature and partial pressure of methane and indicated that the reaction of deactivation can be modeled by a simple apparent second order of reaction
Growth of single-walled carbon nanotubes on a Co–Mo–MgO supported catalyst by the CVD of methane in a fixed bed reactor: Model setting and parameter estimation
In this work methane was decomposed to hydrogen and carbon to determine its kinetic behavior during reaction over a Co–Mo–MgO supported catalyst using the CVD (Chemical Vapor Deposition) technique. Decomposition of methane molecules was performed in a continuous fixed bed reactor to obtain data to simulate methane decomposition in a gas phase heterogeneous media. The products and reactants of reaction were analyzed by molecular sieve column followed by GC-analysis of the fractions to determine the amount of product converted or reactant consumed. The synthesis of single-walled carbon nanotubes was performed at atmospheric pressure, different temperatures and reactant concentrations. The experimental data analyzed to suggest the formula for calculation of the initial specific reaction rate of the carbon nanotubes synthesis, were fitted by several mathematical models derived from different mechanisms based on Longmuir-hinshelwood expression. The suggested mechanism according to dissociation adsorption of methane seems to explain the catalytic performance in the range of operating conditions studied. The apparent activation energy for the growth of SWNTs was estimated according to Arrhenius equation. The as grown SWNTs products were characterized by SEM, TEM and Raman spectroscopy after purification. The catalyst deactivation was found to be dependent on the time, reaction temperature and partial pressure of methane and indicated that the reaction of deactivation can be modeled by a simple apparent second order of reaction