Feasibility of Expanding the Use of Steel Slag as a Concrete Pavement Aggregate

Sustainability has become an important aspect of developed countries throughout the world. Sustainability is the ability to use byproducts and or waste materials from industry and recycle these materials in such a way that the application of the materials provides a beneficial use in the manufacturing or construction sector. As the United States and the rest of the world continue to grow, so too does the demand on the limited natural resources throughout the world. It is this demand on the resources that has brought the idea of sustainability to the forefront of research and design.The transportation industry continues to incorporate sustainability into its projects. The industry is constantly trying new and innovative ways to recycle materials that would otherwise be sent to a landfill. Slag, a byproduct from the production of steel, is one of these materials. The transportation sector has used slags as aggregates for subbase and base layers in roads. Some slags, like blast furnace slag, have been used in portland concrete cement (PCC) applications as well. The focus of this research is to investigate the feasibility of using steel slag as an aggregate for use in portland concrete cement.An important aspect of this research was to complete a comprehensive review of other research that has been conducted on the use of steel slag as an aggregate. The literature reviewed included of laboratory studies that focused on the physical, mechanical, chemical, and expansive characteristics of the steel slag. The research on the use of steel slag was gathered from 16 different countries, which include the United States, Spain, Japan, China, Germany, Finland, and Saudi Arabia. Some of these studies have found that properly treated slag may be non-expansive and used in PCC. The possible expansion of the steel slag is the most important characteristic. The expansion of the steel slag aggregate can have detrimental effects on a pavement. This research investigated some of the treatment processes that are being used to alter t

Feasibility of Expanding the Use of Steel Slag as a Concrete Pavement Aggregate

Sustainability has become an important aspect of developed countries throughout the world. Sustainability is the ability to use byproducts and or waste materials from industry and recycle these materials in such a way that the application of the materials provides a beneficial use in the manufacturing or construction sector. As the United States and the rest of the world continue to grow, so too does the demand on the limited natural resources throughout the world. It is this demand on the resources that has brought the idea of sustainability to the forefront of research and design.The transportation industry continues to incorporate sustainability into its projects. The industry is constantly trying new and innovative ways to recycle materials that would otherwise be sent to a landfill. Slag, a byproduct from the production of steel, is one of these materials. The transportation sector has used slags as aggregates for subbase and base layers in roads. Some slags, like blast furnace slag, have been used in portland concrete cement (PCC) applications as well. The focus of this research is to investigate the feasibility of using steel slag as an aggregate for use in portland concrete cement.An important aspect of this research was to complete a comprehensive review of other research that has been conducted on the use of steel slag as an aggregate. The literature reviewed included of laboratory studies that focused on the physical, mechanical, chemical, and expansive characteristics of the steel slag. The research on the use of steel slag was gathered from 16 different countries, which include the United States, Spain, Japan, China, Germany, Finland, and Saudi Arabia. Some of these studies have found that properly treated slag may be non-expansive and used in PCC. The possible expansion of the steel slag is the most important characteristic. The expansion of the steel slag aggregate can have detrimental effects on a pavement. This research investigated some of the treatment processes that are being used to alter t

Mortality in Peripheral Arterial Disease: A Comparison of Patients Managed by Vascular Specialists and General Practitioners

BACKGROUND: Peripheral arterial disease (PAD) is undertreated by general practitioners (GPs). However, the impact of the suboptimal clinical management is unknown. OBJECTIVE: To assess the mortality rate of PAD patients in relation to the type of physician who provides their care (GP or vascular specialist). DESIGN: Prospective study. SETTING: Primary care practice and academic vascular laboratory. PARTICIPANTS: GP patients (n = 60) were those of the Peripheral Arteriopathy and Cardiovascular Events study (PACE). Patients managed by specialists (n = 82) were consecutive subjects with established PAD who were referred to our vascular laboratory during the enrolment period of the PACE study. MEASUREMENTS: All-cause and cardiovascular mortality. RESULTS: After 32 months of follow-up, specialist management was associated with a lower rate of all-cause mortality (RR = 0.04; 95% CI 0.01–0.34; p = .003) and cardiovascular mortality (RR = 0.07; 95% CI 0.01–0.65; p = .020), after adjustment for patients’ characteristics. Specialists were more likely to use antiplatelet agents (93% vs 73%, p < .001), statins (62% vs 25%, p < .001) and beta blockers (28% vs 3%, p < .001). Survival differences between specialists and GPs disappeared once the use of pharmacotherapies was added to the proportional hazard model. The fully adjusted model showed that the use of statins was significantly associated with a reduced risk of all-cause mortality (RR = 0.02; 95% CI 0.01–0.73, p = .034) and cardiovascular mortality (RR = 0.02; 95% CI 0.01–0.71, p = .033). CONCLUSIONS: Specialist management of patients with symptomatic PAD resulted in better survival than generalist management. This effect appears to be mainly caused by the more frequent use of effective medicines by specialists

Ankle brachial index combined with Framingham risk score to predict cardiovascular events and mortality - A meta-analysis

CONTEXT: Prediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction. OBJECTIVE: To determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction. DATA SOURCES: Relevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies. STUDY SELECTION: Studies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality. DATA EXTRACTION: Prespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease. RESULTS: Sixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women. CONCLUSION: Measurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS

Endothelial Function: The Impact of Objective and Subjective Socioeconomic Status on Flow-Mediated Dilation

Although objective and subjective indicators of socioeconomic status (SES) are linked to cardiovascular disease (CVD), little is known about their relationship to endothelial dysfunction, which often precedes CVD. This study examined how objective and subjective SES relate to brachial artery flow-mediated dilation (FMD). FMD was assessed in 72 healthy adults (mean age 36 years). The MacArthur Scale of Subjective Social Status assessed perceived social standing in the USA (SSS-USA) and local community (SSS-Community). Objective SES measures included income and the Hollingshead Two-Factor Index of Social Position (education, occupation). Adjusted regressions revealed that SSS-Community positively correlated with FMD (p &lt; 0.05) and explained 8% of the variance. No other SES measures were significant for FMD. The association between FMD and SSS-Community remained significant (p &lt; 0.01) after adjustment for objective SES and other covariates. Lower subjective social status in one’s community may be linked to CVD via impaired vasodilation

Heritability of the dimensions, compliance and distensibility of the human internal jugular vein wall

AIMS: The elasticity of the internal jugular vein (IJV) is a major determinant of cerebral venous drainage and right atrium venous return. However, the level of genetic determination of IJV dimensions, compliance and distensibility has not been studied yet. METHODS: 170 adult Caucasian twins (43 monozygotic [MZ] and 42 dizygotic [DZ] pairs) were involved from the Italian twin registry. Anteroposterior and mediolateral diameters of the IJV were measured bilaterally by ultrasonography. Measurements were made both in the sitting and supine positions, with or without Valsalva maneuver. Univariate quantitative genetic modeling was performed. RESULTS: Genetic factors are responsible for 30-70% of the measured properties of IJV at higher venous pressure even after adjustment for age and gender. The highest level of inheritance was found in the supine position regarding compliance (62%) and venous diameter during Valsalva (69%). Environmental and measurement-related factors instead are more important in the sitting position, when the venous pressure is low and the venous lumen is almost collapsed. The range of capacity changes between the lowest and highest intraluminal venous pressure (full distension range) are mainly determined by genetic factors (58%). CONCLUSIONS: Our study has shown substantial heritability of IJV biomechanics at higher venous pressures even after adjustment for age and gender. These findings yield an important insight to what degree the geometric and elastic properties of the vascular wall are formed by genetic and by environmental factors in humans

A multiple timepoint pre-post evaluation of a ‘sexual respect’ dvd to improve competence in discussing sex with patients with disability

Sexual problems are common after chronic illnesses and disability, yet research indicates that this is a neglected area in healthcare services. Evaluation studies provide evidence of the effectiveness of education in enhancing professionals’ knowledge, skills, and comfort in addressing patients’ sexual concerns. However, there are limited evaluations aimed at improving ability to discuss sexuality when working with people with disabilities. The overall aim of this study was to evaluate a ‘Sexual Respect’ DVD as an intervention to improve competence in addressing ‘sexuality and disability’. A mixed methods design was used with both quantitative and qualitative components. Nursing students’ self-report ratings of knowledge, confidence, comfort and willingness (to discuss sexuality) levels were collected across four time points: baseline, pre-intervention, post-intervention, and follow-up. Data were analysed using one-way repeated measures ANOVAs with post hoc comparisons. Open-ended qualitative comments relating to the barriers and facilitators to discussing sexuality were analysed using content analysis and subsequent frequency analysis. Reported barriers included lack of knowledge about sex¬uality and disability issues, the patient’s level of disability, and waiting for the patient to raise sexuality issues first. Facilitators included education/training, written information, and if the patient raised it first. Overall, the DVD intervention had a significant and positive impact on nursing students’ self-reported knowledge, confidence, comfort and willingness levels. The findings are discussed in relation to the PLISSIT model, which emphasises the importance of a proactive approach to addressing sexuality issues

The association between elevated ankle systolic pressures and peripheral occlusive arterial disease in diabetic and nondiabetic subjects

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