25 research outputs found
Impact dynamics of granular debris flows based on a small-scale physical model
The peak pressure of a granular debris flow at low Froude conditions can be calculated with knowledge of the stress anisotropy and the bulk density as well as the run-up height at impact. Based on a small-scale physical model, measurements of stress anisotropy and flow density values at impact are presented and applied to existing run-up prediction models, and further compared with back-calculated run-up coefficients from measured maximum impact pressures. For this purpose, we conducted 17 experiments with impact measurements and six experiments without impact measurements at Froude numbers, ranging from 0.84 to 2.41. Our results indicate that run-up heights are best reproduced by predictive models, either based on energy or mass and moment conservation, when anisotropic stress conditions, found in this study to range from 1.2 to 5.0, and bulk density variations due to impact, ranging in this study from 0.8 to 2.3, are considered. The influence of stress anisotropy and density variation on the run-up prediction differs, depending on the modelling approach. For the calculation of run-up heights based on the energy conservation concept, the influence of stress anisotropy becomes more significant with increasing Froude number, whereas for models based on mass and momentum conservation, bulk density variations have a greater influence on the estimation of the potential run-up
Asymmetric Synthesis of Cyclic Hydroxy Ketones Derived from Enol Ethers via Sharpless Asymmetric Dihydroxylation. A Study in the Correlation of the Enol Ether Chain Length and Enantioselectivity
Outcomes After Severe Distal Tibia, Ankle, and/or Foot Trauma: Comparison of Limb Salvage Versus Transtibial Amputation (OUTLET)
Severe foot and ankle injuries are complex and challenging to treat, often requiring multiple operations to salvage the limb contributing to a prolonged healing period. There is some evidence to suggest that early amputation for some patients may result in better long-term outcomes than limb salvage. The challenge is to identify the regional injury burden for an individual that would suggest a better outcome with an amputation. The OUTLET study is a prospective, multicenter observational study comparing 18-month outcomes after limb salvage versus early amputation among patients aged 18-60 years with severe distal tibia, ankle, and foot injuries. This study aims to build upon the previous work of the Lower Extremity Assessment Project by identifying the injury and patient characteristics that help define a subgroup of salvage patients who will have better outcomes had they undergone a transtibial amputation
Physician Satisfaction with Chronic Care Processes: A Cluster-Randomized Trial of Guided Care
PURPOSE Chronically ill older patients with multiple conditions are challenging to care for, and new models of care for this population are needed. This study evaluates the effect of the Guided Care model on primary care physicians’ impressions of processes of care for chronically ill older patients
Effect of Severe Distal Tibia, Ankle, and Mid- to Hindfoot Trauma on Meeting Physical Activity Guidelines 18 Months After Injury
ObjectiveTo examine the effect of severe lower extremity trauma on meeting Physical Activity Guidelines for Americans (PAGA) 18 months after injury and perform an exploratory analysis to identify demographic, clinical, and psychosocial factors associated with meeting PAGA.DesignSecondary analysis of observational cohort study.SettingA total of 34 United States trauma centers PARTICIPANTS: A total of 328 adults with severe distal tibia, ankle and mid- to hindfoot injuries treated with limb reconstruction (N=328).InterventionsNone.Main outcome measuresThe Paffenbarger Physical Activity Questionnaire was used to assess physical activity levels 18 months after injury. Meeting PAGA was defined as combined moderate- and vigorous-intensity activity ≥150 minutes per week or vigorous-intensity activity ≥75 minutes per week.ResultsFewer patients engaged in moderate- or vigorous-intensity activity after injury compared with before injury (moderate: 44% vs 66%, P<.001; vigorous: 18% vs 29%; P<.001). Patients spent 404±565 minutes per week in combined moderate- to vigorous-intensity activity before injury compared with 224±453 minutes postinjury (difference: 180min per week; 95% confidence interval [CI], 103-256). The adjusted odds of meeting PAGA were lower for patients with depression (adjusted odds ratio [AOR], 0.45; 95% CI, 0.28-0.73), women (AOR, 0.59; 95% CI, 0.35-1.00), and Black or Hispanic patients (AOR, 0.49; 95% CI, 0.28-0.85). Patients meeting PAGA prior to injury were more likely to meet PAGA after injury (odds ratio, 2.0; 95% CI, 1.20-3.31).ConclusionsPatients spend significantly less time in moderate- to vigorous-intensity physical activity after injury. Patients with depression are less likely to meet PAGA. Although the causal relationship is unclear, results highlight the importance of screening for depression