Evaluation of full scale shear performance of tension anchor foundations: Load displacement curves and failure criteria

One of the biggest challenges faced by the offshore wave and tidal energy industry is the high cost of constructing and installing offshore foundations. Foundations based on post tensioned pile anchors can be effectively proposed to tackle this issue. A series of full-scale direct shear tests were performed on-shore to evaluate the shear resistance of post-tensioned pile anchor foundations designed for securing tidal turbine devices to a rock seabed. We focused, in particular, on the primary shear resistance mechanism of post-tensioned anchors, by applying a vertical force which mobilizes, a frictional force able to resist horizontal thrusts. Different load paths, involving monotonic or cyclic loading, were applied; several configurations for the footing of the foundation were tested. The footing stress-displacement behavior and the stress conditions at sliding failure from a number of different testing configurations were compared and analyzed. A marked consistency with the shear performance of natural rock joints was identified. This allows the behavior of tension pile foundations subjected to substantial horizontal loads to be modelled using relationships developed for rock joints, widely available in the literature. Additionally, the results obtained from different tests were also collated considering the various configurations adopted for the foundation-rock system and the applied load paths, to identify the factors that affect the shear resistance of the foundation.

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

A Multicenter, Randomized, Placebo‐Controlled Trial of Atorvastatin for the Primary Prevention of Cardiovascular Events in Patients With Rheumatoid Arthritis

Objective: Rheumatoid arthritis (RA) is associated with increased cardiovascular event (CVE) risk. The impact of statins in RA is not established. We assessed whether atorvastatin is superior to placebo for the primary prevention of CVEs in RA patients. Methods: A randomized, double‐blind, placebo‐controlled trial was designed to detect a 32% CVE risk reduction based on an estimated 1.6% per annum event rate with 80% power at P 50 years or with a disease duration of >10 years who did not have clinical atherosclerosis, diabetes, or myopathy received atorvastatin 40 mg daily or matching placebo. The primary end point was a composite of cardiovascular death, myocardial infarction, stroke, transient ischemic attack, or any arterial revascularization. Secondary and tertiary end points included plasma lipids and safety. Results: A total of 3,002 patients (mean age 61 years; 74% female) were followed up for a median of 2.51 years (interquartile range [IQR] 1.90, 3.49 years) (7,827 patient‐years). The study was terminated early due to a lower than expected event rate (0.70% per annum). Of the 1,504 patients receiving atorvastatin, 24 (1.6%) experienced a primary end point, compared with 36 (2.4%) of the 1,498 receiving placebo (hazard ratio [HR] 0.66 [95% confidence interval (95% CI) 0.39, 1.11]; P = 0.115 and adjusted HR 0.60 [95% CI 0.32, 1.15]; P = 0.127). At trial end, patients receiving atorvastatin had a mean ± SD low‐density lipoprotein (LDL) cholesterol level 0.77 ± 0.04 mmoles/liter lower than those receiving placebo (P < 0.0001). C‐reactive protein level was also significantly lower in the atorvastatin group than the placebo group (median 2.59 mg/liter [IQR 0.94, 6.08] versus 3.60 mg/liter [IQR 1.47, 7.49]; P < 0.0001). CVE risk reduction per mmole/liter reduction in LDL cholesterol was 42% (95% CI −14%, 70%). The rates of adverse events in the atorvastatin group (n = 298 [19.8%]) and placebo group (n = 292 [19.5%]) were similar. Conclusion: Atorvastatin 40 mg daily is safe and results in a significantly greater reduction of LDL cholesterol level than placebo in patients with RA. The 34% CVE risk reduction is consistent with the Cholesterol Treatment Trialists’ Collaboration meta‐analysis of statin effects in other populations

Association Between Statin Use and Uveitis: Results From the Pacific Ocular Inflammation Study

PURPOSE: To assess whether there is a protective association between statin use and uveitis diagnosis DESIGN: Retrospective, population-based case-control study METHODS: Medical records of all patients in the Kaiser Permanente Hawaii health plan between January 1, 2006 and December 31, 2007 (N=217,061) were searched electronically for International Classification of Diseases, 9(th) Revision, diagnosis codes related to uveitis. Chart review was done to confirm incident uveitis diagnosis during the study period. Two control groups were each randomly selected at a 5:1 ratio to cases, and controls were assigned an index date to match their respective case diagnosis date. One control group was selected from the general Kaiser Permanente Hawaii population that had at least one healthcare visit during the study period. Another control group was selected from the population of Kaiser Permanente Hawaii members who had at least one visit to the ophthalmology clinic during the study period. Statin use was defined as filling a prescription for statin medication in the year prior to the diagnosis or index date based on an electronic search of the Kaiser Permanente Hawaii pharmacy database for Generic Product Identification codes. A conditional logistic regression model with clinical diagnosis of uveitis as the outcome was used to assess the relationship between statin use and uveitis. RESULTS: One hundred eight incident cases of uveitis were identified. Nineteen percent of uveitis patients had used statin medication in the year prior to diagnosis compared to 30% of patients in the general Kaiser population control (p=0.03) and 38% of patients in the ophthalmology clinic control (p<0.001). Using the general Kaiser population control and adjusting for age, gender, race, and autoimmune diseases, the odds of a statin user developing uveitis were 48% less than the odds of a non-statin user developing uveitis (OR: 0.52, 95% CI: 0.29 to 0.94, p=0.03). Similarly, the odds of developing uveitis were 33% less for statin users compared to non-statin users (OR: 0.67, 95% CI: 0.38 to 1.19, p=0.17) when adjusting for these factors and using the ophthalmology clinic control group. CONCLUSIONS: Statin use may be protective against the development of uveitis. Several anti-inflammatory and immunomodulatory mechanisms may explain this association