Reducing Implant Infection in Orthopaedics (RIIiO): a pilot study for a randomised controlled trial comparing the influence of forced air versus resistive fabric warming technologies on postoperative infection rates following orthopaedic implant surgery in adults

Background Approximately 70,000 to 75,000 proximal femoral fracture repairs take place in the UK each year. Hemiarthroplasty is the preferred treatment for adults aged over 60 years. Postoperative infection affects up to 3% of patients and is the single most common reason for early return to theatre. Ultraclean ventilation was introduced to help mitigate the risk of infection, but it may also contribute to inadvertent perioperative hypothermia, which itself is a risk for postoperative infection. To counter this, active intraoperative warming is used for all procedures that take 30 min or more. Forced air warming (FAW) and resistive fabric warming (RFW) are the two principal techniques used for this purpose; they are equally effective in prevention of inadvertent perioperative hypothermia, but it is not known which is associated with the lowest infection rates. Deep surgical site infection doubles operative costs, triples investigation costs and quadruples ward costs. The Reducing Implant Infection in Orthopaedics (RIIiO) study seeks to compare infection rates with FAW versus RFW after hemiarthroplasty for hip fracture. A cost-neutral intervention capable of reducing postoperative infection rates would likely lead to a change in practice, yield significant savings for the health economy, reduce overall exposure to antibiotics and improve outcomes following hip fracture in the elderly. The findings may be transferable to other orthopaedic implant procedures and to non-orthopaedic surgical specialties. Methods RIIiO is a parallel group, open label study randomising hip fracture patients over 60 years of age who are undergoing hemiarthroplasty to RFW or FAW. Participants are followed up for 3 months. Definitive deep surgical site infection within 90 days of surgery, the primary endpoint, is determined by a blinded endpoint committee. Discussion Hemiarthroplasty carries a risk of deep surgical site infection of approximately 3%. In order to provide 90% power to demonstrate an absolute risk reduction of 1%, using a 5% significance level, a full trial would need to recruit approximately 8630 participants. A pilot study is being conducted in the first instance to demonstrate that recruitment and data management strategies are appropriate and robust before embarking on a large multi-centre trial

Reducing the hardware requirements in FPGA based controllers: a photovoltaic application

Sistemas fotovoltaicos monofásicos experimentan oscilaciones de voltaje debido a la diferencia entre la potencia promedio generada y la potencia instantánea inyectada a la red. Estas oscilaciones de voltaje degradan la producción de potencia. Este artículo propone una solución para mitigar las oscilaciones propagadas a las terminales del generador, la cual minimiza los recursos de hardware requeridos para implementar la técnica de compensación de un dispositivo FPGA, permitiendo su coexistencia con algoritmos de control adicionales en un solo dispositivo. La efectividad de la solución se valida experimentalmente, y sus requerimientos de hardware se contrastan con soluciones basadas en plataformas comerciales

A fast current-based MPPT technique based on sliding mode control

This paper introduces a novel maximum power point tracking technique aimed at maximizing the power produced by photovoltaic systems. The largest part of the approaches presented in literature are based on the sensing of the photovoltaic generator voltage. On the contrary, in this paper a current-based technique is proposed: the sensing of the current in the capacitor placed in parallel with the photovoltaic source is one of the innovative aspects of the proposal. A dual control loop based on the sliding mode control ensures a very fast tracking of irradiation variations. Features of the proposed algorithm are supported by a theoretical analysis and simulations. The technique described in this paper is patent pending

A fast current-based MPPT technique based on sliding mode control

This paper introduces a novel maximum power point tracking (MPPT) technique aimed at maximizing the power produced by photovoltaic (PV) systems. The largest part of the MPPT approaches presented in the literature are based on the sensing of the PV generator voltage. On the contrary, in this paper, a current-based technique is proposed: the sensing of the current in the capacitor placed in parallel with the PV source is one of the innovative aspects of the proposal. A dual control technique based on an inner current loop plus an outer voltage loop allows to take profit of the fast current tracking capability of the inner current loop while the voltage loop benefits from the logarithmic dependency of the PV voltage on the irradiation level. The features of the proposed algorithm, particularly in terms of tracking of irradiation variations and disturbance rejection, are supported by theoretical analysis, simulations, and experimental results. The technique described in this paper is patent pending

Perturb and Observe MPPT-algorithm with a Current Controller based on the Sliding Mode

In this paper a current controller is used to reject the 100-Hz oscillation of the voltage of the photovoltaic field taking place in any grid connected system. With respect to the classical linear voltage control the current-based sliding-mode approach ensures a wider regulation band but, unfortunately, in presence of a fast irradiance variation the sliding conditions might be violated, so that the operating point, which should be the maximum power point, might not be the expected one. In order to prevent such a drawback, an appropriate voltage compensation loop is used to interface the current-based sliding mode with the Maximum Power Point Tracking algorithm. Simulation and experimental results confirm the goodness of the proposed algorithm

Oxidative stress in ageing and disease development studied by FT-IR spectroscopy

FT-IR spectroscopy was used to investigate the effect of oxidative stress and to approach the mechanism on cancer bone demineralization, aortic valve mineralization and heterotopic ossification on disease development. The FT-IR spectra obtained from paediatric, adult bone and ex vivo irradiated adult healthy bone with a dose of 20 Gy were compared with those of healthy bone. The increase of band intensity changes of vasCH2 vsCH2 in the region 3000–2850 cm−1 depended on aging, the disease progression and the dose of irradiation. The bands at 3080 cm−1 and 1744 cm−1, which originate from olefinic terminal bond (v = CH) and ester carbonyl group (vRO–C[dbnd]O), respectively, indicate the influence of oxidative stress on lipid degradation and peroxidation, respectively. The new bands at about 1690 cm−1 and 1516 cm−1 denote the presence of β-sheet conformation of the proteins due to the diseases, confirming the increasing amount of lipophilic environment and fibril formation. Comparison of the FT-IR spectra of calcified aortic valve and hip heterotopic ossification with that of normal bones showed that in the bone-like formation the peroxide anion free radicals play an important role in the disease. © 2017 Elsevier B.V