Fatigue-Life Prediction Methodology Using Small-Crack Theory

This paper reviews the capabilities of a plasticity-induced crack-closure model to predict fatigue lives of metallic materials using 'small-crack theory' for various materials and loading conditions. Crack-tip constraint factors, to account for three-dimensional state-of-stress effects, were selected to correlate large-crack growth rate data as a function of the effective-stress-intensity factor range (delta K(eff)) under constant-amplitude loading. Some modifications to the delta k(eff)-rate relations were needed in the near-threshold regime to fit measured small-crack growth rate behavior and fatigue endurance limits. The model was then used to calculate small- and large-crack growth rates, and to predict total fatigue lives, for notched and un-notched specimens made of two aluminum alloys and a steel under constant-amplitude and spectrum loading. Fatigue lives were calculated using the crack-growth relations and microstructural features like those that initiated cracks for the aluminum alloys and steel for edge-notched specimens. An equivalent-initial-flaw-size concept was used to calculate fatigue lives in other cases. Results from the tests and analyses agreed well

K/DOQI Clinical Practice Guidelines on Hypertension and Antihypertensive Agents in Chronic Kidney Disease

INTRODUCTION: CHRONIC KIDNEY disease (CKD) is a worldwide public health issue. In the United States, there is a rising incidence and prevalence of kidney failure (Fig 1), with poor outcomes and high cost. The prevalence of earlier stages of CKD is approximately 100 times greater than the prevalence of kidney failure, affecting almost 11% of adults in the United States. There is growing evidence that some of the adverse outcomes of CKD can be prevented or delayed by preventive measures, early detection, and treatment. Hypertension is a cause and complication of CKD. Hypertension in CKD increases the risk of important adverse outcomes, including loss of kidney function and kidney failure, early development and accelerated progression of cardiovascular disease (CVD), and premature death. In the ongoing effort to improve outcomes of CKD, the National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (K/DOQI) appointed a Work Group and an Evidence Review Team in 2001 to develop clinical practice guidelines on hypertension and use of antihypertensive agents in CKD. During this same time, clinical practice guidelines on this topic relevant to CKD were also under development by other organizations, including the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) and the 2003 report of the American Diabetes Association (ADA) on the Treatment of Hypertension in Adults with Diabetes. The Work Group maintained contact with these organizations during development of these guidelines. The purpose of the Executive Summary is to provide a "stand-alone" summary of the background, scope, methods, and key recommendations, as well as the complete text of the guideline statements. Most tables and figures in the Executive Summary are taken from other sections of the document. BACKGROUND: Chronic Kidney Disease: Figure 2 is a conceptual model of CKD, which defines stages of CKD, as well as antecedent conditions, outcomes, risk factors for adverse outcomes, and actions to improve outcomes. CKD is defined as kidney damage, as confirmed by kidney biopsy or markers of damage, or glomerular filtration rate (GFR

K/DOQI Clinical Practice Guidelines on Hypertension and Antihypertensive Agents in Chronic Kidney Disease

INTRODUCTION: CHRONIC KIDNEY disease (CKD) is a worldwide public health issue. In the United States, there is a rising incidence and prevalence of kidney failure (Fig 1), with poor outcomes and high cost. The prevalence of earlier stages of CKD is approximately 100 times greater than the prevalence of kidney failure, affecting almost 11% of adults in the United States. There is growing evidence that some of the adverse outcomes of CKD can be prevented or delayed by preventive measures, early detection, and treatment. Hypertension is a cause and complication of CKD. Hypertension in CKD increases the risk of important adverse outcomes, including loss of kidney function and kidney failure, early development and accelerated progression of cardiovascular disease (CVD), and premature death. In the ongoing effort to improve outcomes of CKD, the National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (K/DOQI) appointed a Work Group and an Evidence Review Team in 2001 to develop clinical practice guidelines on hypertension and use of antihypertensive agents in CKD. During this same time, clinical practice guidelines on this topic relevant to CKD were also under development by other organizations, including the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) and the 2003 report of the American Diabetes Association (ADA) on the Treatment of Hypertension in Adults with Diabetes. The Work Group maintained contact with these organizations during development of these guidelines. The purpose of the Executive Summary is to provide a "stand-alone" summary of the background, scope, methods, and key recommendations, as well as the complete text of the guideline statements. Most tables and figures in the Executive Summary are taken from other sections of the document. BACKGROUND: Chronic Kidney Disease: Figure 2 is a conceptual model of CKD, which defines stages of CKD, as well as antecedent conditions, outcomes, risk factors for adverse outcomes, and actions to improve outcomes. CKD is defined as kidney damage, as confirmed by kidney biopsy or markers of damage, or glomerular filtration rate (GFR

The long-term health consequences of child physical abuse, emotional abuse, and neglect: a systematic review and meta-analysis

Background: Child sexual abuse is considered a modifiable risk factor for mental disorders across the life course. However the long-term consequences of other forms of child maltreatment have not yet been systematically examined. The aim of this study was to summarise the evidence relating to the possible relationship between child physical abuse, emotional abuse, and neglect, and subsequent mental and physical health outcomes