Recommended vaccinations for asplenic and hyposplenic adult patients

Asplenic or hyposplenic (AH) individuals are particularly vulnerable to invasive infections caused by encapsulated bacteria. Such infections have often a sudden onset and a fulminant course. Infectious diseases (IDs) incidence in AH subjects can be reduced by preventive measures such as vaccination. The aim of our work is to provide updated recommendations on prevention of infectious diseases in AH adult patients, and to supply a useful and practical tool to healthcare workers for the management of these subjects, in hospital setting and in outpatients consultation. A systematic literature review on evidence based measures for the prevention of IDs in adult AH patients was performed in 2015. Updated recommendations on available vaccines were consequently provided. Vaccinations against S. pneumoniae, N. meningitidis, H. influenzae type b and influenza virus are strongly recommended and should be administered at least 2 weeks before surgery in elective cases or at least 2 weeks after the surgical intervention in emergency cases. In subjects without evidence of immunity, 2 doses of live attenuated vaccines against measles-mumps-rubella and varicella should be administered 4–8 weeks apart from each other; a booster dose of tetanus, diphtheria and pertussis vaccine should be administered also to subjects fully vaccinated, and a 3-dose primary vaccination series is recommended in AH subjects with unknown or incomplete vaccination series (as in healthy people). Evidence based prevention data support the above recommendations to reduce the risk of infection in AH individuals

Choice of the stress integration scheme for accurate large-deformation finite element analysis

The use of computational structural models that include geometrical non-linearity in many application cases may require high reliability in prediction of displacements. Nevertheless, large differences up to 60% on maximum total displacement have been found among results of static large-deformation analyses performed by means of the major commercial software packages in a simple benchmark study with linear material properties. In order to investigate the causes of such disagreement, the present work compares different finite element formulations including well-established stress update schemes. The various formulations are tested, and results are compared in three test cases. Rodriguez stress update algorithms have shown the best performance among methods reported in literature. Finally, the cause of the large differences found in the predictions of commercial codes is identified. It is linked to the energetic inconsistency of some stress update methods in the simulation of extension/compression loading conditions. Such inaccuracy is reproduced analytically by formulating and integrating the corresponding inconsistent constitutive equations. The identified problem is very important for designers, as it affects almost all the static simulations, which are the most common type of largedeformation analyses and usually involve extension/compression loading

Development of a new test rig for the analysis of hydrodynamic bearings for rotors of microGT

The aim of the present work is to design a test rig suited to investigate the dynamic interaction between rotor and hydrodynamic journal bearings in micro gas turbines (microGT), i.e. with reference to small bearings (diameter in the order of ten millimeters). Particularly, the device is capable of measuring the journal location. Therefore, the journal motion due to rotor vibrations can be displayed, in order to assess performance as well as stiffness and damping of the bearings. The new test rig is based on Bently Nevada Rotor Kit (RK), but substantial modifications are carried out. Indeed, the relative radial clearance of the original RK bearings is about 2/100, while it is in the order of 1/1000 in industrial bearings. Therefore, the same RK bearings are employed in the new test rig, but a new shaft has been designed in order to reduce the original clearance. The new shaft enables us to study the bearing behaviour for different clearances, as it is equipped with interchangeable journals. The experimental data yielded by the new test rig are compared with numerical results. These are obtained by means of a suitable finite element (FEM) code developed by our research group. It allows the Thermo Elasto-HydroDynamic (TEHD) analysis of the bearing in static and dynamic conditions. In the present paper, bearing static performances are analysed in order to assess the reliability of the journal location predictions by comparing numerical and experimental results. Such comparisons are presented for both large and small clearance bearings of original and modified RK, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance equal to 8/1000). Nevertheless, rotor alignment is quite difficult with small clearance bearings and a completely new test rig is designed for future experiments

A Methodology For Technolgy Risk Assessment in Hospitals

The health model is a complex system in which interact multiple factors including the continuous growing use of biomedical technologies in the clinical activity. This paper aims to provide to the technology decision makers in healthcare (Health Management, Clinical Engineering and Prevention and Protection Service) a decision support system for analyzing the safety level associated to the use of technology for both patients and personnel. The evaluation was carried out to different levels: 'Equipment', 'Hospital department', 'hospital' and 'Local Health System.' Moreover, the system provided a 'simulation mode' which permits to build different scenarios resulting from the application of different improving solutions such as the quality improvement of training phase or increasing the frequency of preventive maintenance actions. The system is based on the use of simple or combined indicators which were classified into five different categories depending on the area of application: 'Technical Maintenance,' 'Intrinsic Safety-Usability- Ergonomics,' 'Intrinsic Criticality,' 'Process and Training' and 'Operational Risk.' Finally the system was applied to the Florence digestive endoscopy department

A methodology aimed to guarantee technology continuity in health structures

In healthcare the importance of clinical continuity is essential for both patients life and health organization activity. Since technology continuity is having more and more importance for the service continuity, a correct management of medical devices must be guided by criteria that ensure its safe, appropriate and economical use through a well planned purchase, appropriate preventive and corrective maintenance Indeed, the aim of health technology managers is to optimize the integration of external interventions assistance and internal technical service to guarantee an efficient and cost-effective maintenance system. This paper proposes an innovative carefully thought methodology which is aimed to provide technological and procedural actions which offer support to decision makers in technology management regarding the implementation of continuity in medical services and response to technology failures and emergency events

Hysteresis and torsional-lateral vibration coupling in a complex shaft line supported by hydrodyanamic journal bearings

In some rotating machinery for specific industrial applications the driving as well as resistance torques or the inertias reduced to the rotation axis may be nonstationary, thus affecting system dynamics. Under such operating conditions, in some peculiar cases torsional response and rotational motion irregularity may influence system lateral vibrations. The present paper shows how such coupling phenomena may become significant in particular conditions, where the occurrence of fluid–structure interactions causes a reduction in stability threshold of hydrodynamic journal bearings and torsional energy yields a hysteresis behaviour in system synchronous lateral response. A hypothesis based on Hopf bifurcation theory (HBT) is formulated in order to justify how and under which operating conditions such coupling phenomenon can develop. In order to validate such hypothesis, an experimental campaign is performed on a real-size shaft line including a TG rotor for heavy-duty power plants mounted on hydrodynamic bearings. The detected rotor-bearings system lateral operating response is found to become more complex in presence of a pulsating driving torque inducing significant angular speed oscillation as well as a dynamic perturbation, which causes strong coupling from torsional to lateral vibrations. Such coupling entity has been experimentally found to be dependent from excitation frequency with respect to revolution one. Particularly, localized hysteresis and jump-up phenomena are detected in trends of fundamental order contents measured during run-up and run-down tests when such torsional response is present. Consequently, a hydrodynamic bearing numerical model is built that can solve Reynolds equation in unsteady conditions in order to quantify journal lateral vibrations amplitude in presence of both an angular speed oscillation and a dynamic perturbation, both characterized by well-defined amplitude and characteristic frequency. The proposed approach, validated by means of both suitable measurements and numerical simulations, can justify the existence of such coupling phenomena. The detected anomalous response characterized by localized hysteresis is ascribable to journals unstable behaviour onset within hydrodynamic bearings due to operating angular speed irregularity related to an induced torsional vibration