Characterisation of fatigue crack growth using the CJP model of crack tip fields or plastic CTOD

This paper provides an update on the current status of work that has been done to validate the CJP model of crack tip stresses and also summarises some findings from linked work that has used DIC to determine the range of plastic crack tip opening displacement as a correlator of fatigue crack growth rate. The paper considers several ways of calculating an effective range of stress intensity factor that have been proposed in various papers, as the preferred option is not yet fully clear. It further highlights the potential value, in terms of elucidating the mechanisms involved in plasticity-induced crack tip shielding, arising from data obtained from using two different DIC techniques on the same specimens

Adverse Effect of Nano-Silicon Dioxide on Lung Function of Rats with or without Ovalbumin Immunization

BACKGROUND: The great advances of nanomaterials have brought out broad important applications, but their possible nanotoxicity and risks have not been fully understood. It is confirmed that exposure of environmental particulate matter (PM), especially ultrafine PM, are responsible for many lung function impairment and exacerbation of pre-existing lung diseases. However, the adverse effect of nanoparticles on allergic asthma is seldom investigated and the mechanism remains undefined. For the first time, this work investigates the relationship between allergic asthma and nanosized silicon dioxide (nano-SiO₂). METHODOLOGY/PRINCIPAL FINDINGS: Ovalbumin (OVA)-treated and saline-treated control rats were daily intratracheally administered 0.1 ml of 0, 40 and 80 µg/ml nano-SiO₂ solutions, respectively for 30 days. Increased nano-SiO₂ exposure results in adverse changes on inspiratory and expiratory resistance (Ri and Re), but shows insignificant effect on rat lung dynamic compliance (Cldyn). Lung histological observation reveals obvious airway remodeling in 80 µg/ml nano-SiO₂-introduced saline and OVA groups, but the latter is worse. Additionally, increased nano-SiO₂ exposure also leads to more severe inflammation. With increasing nano-SiO₂ exposure, IL-4 in lung homogenate increases and IFN-γ shows a reverse but insignificant change. Moreover, at a same nano-SiO₂ exposure concentration, OVA-treated rats exhibit higher (significant) IL-4 and lower (not significant) IFN-γ compared with the saline-treated rats. The percentages of eosinophil display an unexpected result, in which higher exposure results lower eosinophil percentages. CONCLUSIONS/SIGNIFICANCE: This was a preliminary study which for the first time involved the effect of nano-SiO₂ to OVA induced rat asthma model. The results suggested that intratracheal administration of nano-SiO₂ could lead to the airway hyperresponsiveness (AHR) and the airway remolding with or without OVA immunization. This occurrence may be due to the Th1/Th2 cytokine imbalance accelerated by the nano-SiO₂ through increasing the tissue IL-4 production

Changes in Cardiac Substrate Transporters and Metabolic Proteins Mirror the Metabolic Shift in Patients with Aortic Stenosis

In the hypertrophied human heart, fatty acid metabolism is decreased and glucose utilisation is increased. We hypothesized that the sarcolemmal and mitochondrial proteins involved in these key metabolic pathways would mirror these changes, providing a mechanism to account for the modified metabolic flux measured in the human heart. Echocardiography was performed to assess in vivo hypertrophy and aortic valve impairment in patients with aortic stenosis (n = 18). Cardiac biopsies were obtained during valve replacement surgery, and used for western blotting to measure metabolic protein levels. Protein levels of the predominant fatty acid transporter, fatty acid translocase (FAT/CD36) correlated negatively with levels of the glucose transporters, GLUT1 and GLUT4. The decrease in FAT/CD36 was accompanied by decreases in the fatty acid binding proteins, FABPpm and H-FABP, the β-oxidation protein medium chain acyl-coenzyme A dehydrogenase, the Krebs cycle protein α-ketoglutarate dehydrogenase and the oxidative phosphorylation protein ATP synthase. FAT/CD36 and complex I of the electron transport chain were downregulated, whereas the glucose transporter GLUT4 was upregulated with increasing left ventricular mass index, a measure of cardiac hypertrophy. In conclusion, coordinated downregulation of sequential steps involved in fatty acid and oxidative metabolism occur in the human heart, accompanied by upregulation of the glucose transporters. The profile of the substrate transporters and metabolic proteins mirror the metabolic shift from fatty acid to glucose utilisation that occurs in vivo in the human heart

The UK INFINITY study - early experience and complications of a multicenter series of 504 total ankle arthroplasties.

Introduction/Purpose: This is the first report from the UK INFINITY study. This is a multicentre, non-inventor, prospective observational study of 504 INFINITY fixed bearing total ankle arthroplasties. We report our early experience, complications, radiographic and functional outcomes of this prosthesis. Methods: Patients were recruited from 11 specialist centres between June 2016 and November 2019. Demographic, radiographic, and functional outcome data (Ankle Osteoarthritis Scale, Manchester Oxford Questionnaire and Euroquol 5D-5L) were collected preoperatively, at 6 months (454 patients), 1 year (328 patients) and 2 years (104 patients). The average age was 67.8 (range 23.9 to 88.5) and average BMI 29.9 (18.9 to 48.0). The COFAS grading system was used to stratify deformity. There were 259 (51.4%) COFAS Type 1, 122 (24.2%) COFAS Type 2, 32 (6.3%) COFAS 3 and 87 (17.3%) COFAS type 4. 38 patients (7.54%) presented with inflammatory arthritis. 101 (20.0%) of implantations utilised patient specific instrumentation (Prophecy). 169 (33.5%) of patients underwent an additional procedure at the time of surgery. Early and late complications and reoperations were recorded as adverse events. Radiographs were assessed for lucencies, cysts and/or subsidence. Results: There was a significant (p<0.01) improvement across all functional outcome scores at 6 months, which was sustained at one and two years. There was no significant difference with the use of patient specific instrumentation. 167 (33.1%) underwent additional procedures at index surgery. At the latest follow up 3 implants (0.6%) have been revised. One patient at 6 weeks for deep infection, one patient at 6 months for subsidence and one patient at 18 months for loosening. There were an additional 13 reoperations (2.6%) at the latest follow up. Conclusion: The UK INFINITY study is the largest reported multicentre study of a Total Ankle Arthroplasty to date. This study has shown a low early revision rate and high functional outcomes of the INFINITY prosthesis

Model-Based Therapeutic Correction of Hypothalamic-Pituitary-Adrenal Axis Dysfunction

The hypothalamic-pituitary-adrenal (HPA) axis is a major system maintaining body homeostasis by regulating the neuroendocrine and sympathetic nervous systems as well modulating immune function. Recent work has shown that the complex dynamics of this system accommodate several stable steady states, one of which corresponds to the hypocortisol state observed in patients with chronic fatigue syndrome (CFS). At present these dynamics are not formally considered in the development of treatment strategies. Here we use model-based predictive control (MPC) methodology to estimate robust treatment courses for displacing the HPA axis from an abnormal hypocortisol steady state back to a healthy cortisol level. This approach was applied to a recent model of HPA axis dynamics incorporating glucocorticoid receptor kinetics. A candidate treatment that displays robust properties in the face of significant biological variability and measurement uncertainty requires that cortisol be further suppressed for a short period until adrenocorticotropic hormone levels exceed 30% of baseline. Treatment may then be discontinued, and the HPA axis will naturally progress to a stable attractor defined by normal hormone levels. Suppression of biologically available cortisol may be achieved through the use of binding proteins such as CBG and certain metabolizing enzymes, thus offering possible avenues for deployment in a clinical setting. Treatment strategies can therefore be designed that maximally exploit system dynamics to provide a robust response to treatment and ensure a positive outcome over a wide range of conditions. Perhaps most importantly, a treatment course involving further reduction in cortisol, even transient, is quite counterintuitive and challenges the conventional strategy of supplementing cortisol levels, an approach based on steady-state reasoning

Intelligent Monitoring and Controlling of Public Policies Using Social Media and Cloud Computing

Part 3: Government and InfrastructureInternational audienceLack of public participation in various policy making decision has always been a major cause of concern for government all around the world while formulating as well as evaluating such policies. With availability of latest IT infrastructure and the migration of government think-tank towards realizing more efficient cloud based e-government, this problem has been partially answered, but this predicament still persists. However, the exponential rise in usage of social media platforms by general public has given the government a wider insight to overcome this long pending dilemma. This paper presents a pragmatic approach that combines the capabilities of cloud computing and social media analytics towards efficient monitoring and controlling of public policies. The proposed arrangement has provided us some encouraging results, when tested for the policy of the century i.e. GST implementation by Indian government and established that proposed system can be successfully implemented for efficient policy making and implementation