Factors influencing consideration of dental specialisation: a survey of current dental students at the University of Western Australia

Aim. At present, little research exists regarding factors that influence dental students and recent graduates to pursue specialist training. Through the provision of a questionnaire, the study investigated student's perceptions of dental specialities and factors impacting specialisation.Methods. Questionnaires (n=65) were undertaken by Doctor of Dental Medicine students in year three (n=34) and four (n=31) through paper means. An analysis was undertaken of the knowledge of speciality courses, speciality preferences and the main motivating and deterring factors influencing specialisation.Results. A response rate of 70% was observed, revealing that 13% of all participants correctly identified the speciality courses available in Western Australia, with 6% of students wanting to specialise in the long term. Altruistic factors were most motivating and financial most deterring when considering specialisation. Speciality preferences also varied between cohorts.Conclusions. Findings highlight that a small proportion of students want to pursue specialisation and the majority of students are unaware of the speciality courses available in Western Australia. This emphasises the need for greater exposure and education in dental specialties. Further research is advised in this field to better understand factors involved in the pathway to dental specialisation and how to encourage specialisation

Informed assessment of structural health conditions of bridges based on free-vibration tests

consolidated procedure for the evaluation of current structural health con-ditions in bridges consists in the comparison between estimated modal features from in-situ tests and numerical values. This strategy allows making informed decisions for existing bridge structures to ensure structural safety or serviceability. Free vibration tests are common in bridges monitoring since they allow a quick and cost-effective determination of dynamic infor-mation about the structure, using a sparse network of few sensors and avoid long-lasting monitoring campaigns. Exploiting an identification method based on a tuned version of Vari-ational Mode Decomposition and an area-ratio based approach, modal parameters are deter-mined from free vibration tests. This technique is applied to the dynamic identification of cables in a stay-cabled bridge assumed as case study: the obtained results prove reliability of the adopted method as a useful tool for objective dynamic identification purposes, with focus on the structural health conditions of bridges

Numerical Simulation of Compressible Vortical Flows Using a Conservative Unstructured-Grid Adaptive Scheme

A two-dimensional numerical scheme for the compressible Euler equations is presented and applied here to the simulation of exemplary compressible vortical flows. The proposed approach allows to perform computations on unstructured moving grids with adaptation, which is required to capture complex features of the flow-field. Grid adaptation is driven by suitable error indicators based on the Mach number and by element-quality constraints as well. At the new time level, the computational grid is obtained by a suitable combination of grid smoothing, edge-swapping, grid refinement and de-refinement. The grid modifications-including topology modification due to edge-swapping or the insertion/deletion of a new grid node-are interpreted at the flow solver level as continuous (in time) deformations of suitably-defined node-centered finite volumes. The solution over the new grid is obtained without explicitly resorting to interpolation techniques, since the definition of suitable interface velocities allows one to determine the new solution by simple integration of the Arbitrary Lagrangian-Eulerian formulation of the flow equations. Numerical simulations of the steady oblique-shock problem, of the steady transonic flow and of the start-up unsteady flow around the NACA 0012 airfoil are presented to assess the scheme capabilities to describe these flows accurately

Prediction and Simulator Verification of Roll/Lateral Adverse Aeroservoelastic Rotorcraft–Pilot Couplings

The involuntary interaction of a pilot with an aircraft can be described as pilot-assisted oscillations. Such phenomena are usually only addressed late in the design process when they manifest themselves during ground/flight testing. Methods to be able to predict such phenomena as early as possible are therefore useful. This work describes a technique to predict the adverse aeroservoelastic rotorcraft–pilot couplings, specifically between a rotorcraft’s roll motion and the resultant involuntary pilot lateral cyclic motion. By coupling linear vehicle aeroservoelastic models and experimentally identified pilot biodynamic models, pilot-assisted oscillations and no-pilot-assisted oscillation conditions have been numerically predicted for a soft-in-plane hingeless helicopter with a lightly damped regressive lead–lag mode that strongly interacts with the roll modeat a frequency within the biodynamic band of the pilots. These predictions have then been verified using real-time flight-simulation experiments. The absence of any similar adverse couplings experienced while using only rigid-body models in the flight simulator verified that the observed phenomena were indeed aeroelastic in nature. The excellent agreement between the numerical predictions and the observed experimental results indicates that the techniques developed in this paper can be used to highlight the proneness of new or existing designs to pilot-assisted oscillation

Wind Tunnel Investigation of a Helicopter Model in Shipboard Operations

The paper presents the wind tunnel simulation of a helicopter model in shipboard operations. The test rig consists of a scaled helicopter model and a simplified ship model, based on the geometry of the Simple Frigate Shape 1. In the first phase of the experiment, pressure and Particle Image Velocimetry survey of the flow field on the flight deck were performed without the presence of the helicopter, to study the flow features on the ship deck, for several wind conditions obtained modifying the wind speed and direction. The influence of Atmospheric Boundary Layer was investigated as well. Then, the rotorcraft was positioned in a series of points representative of both a typical fore-aft landing trajectory toward the deck, and a vertical descent on the deck. Loads generated by the rotor were monitored by means of a six-axis load cell. Particle Image Velocimetry of the ship wake and of the helicopter inflow were carried out in order to have a better understanding of how the interacting flow fields affected the helicopter performance. The test showed a significant effect of the mutual aerodynamic influence between the helicopter and the ship model and a limited effect of the Atmospheric Boundary Layer

Induced pluripotent stem cells in hematology: current and future applications

Reprogramming somatic cells into induced pluripotent stem (iPS) cells is nowadays approaching effectiveness and clinical grade. Potential uses of this technology include predictive toxicology, drug screening, pathogenetic studies and transplantation. Here, we review the basis of current iPS cell technology and potential applications in hematology, ranging from disease modeling of congenital and acquired hemopathies to hematopoietic stem and other blood cell transplantation

The impact of intra-operative factors in otosclerosis outcomes: retrospective study in a tertiary centre

The aim of the study was to assess results from a large cohort of patients undergoing otosclerosis surgery with respect to the impact of intra-operative variables on post-operative hearing function and complications. We enrolled 384 patients affected by otosclerosis who were subjected to stapes surgery between 2004 and 2013 at a single institution. Surgery was performed in all cases under local anaesthesia, using a manual perforator and/or microdrill. Teflon-piston prosthesis was used in all patients. Audiological data obtained preoperatively and at last follow-up examination (minimum 12 months) were compared. Statistical analysis was performed using the multiple regression model. Peripheral rim otosclerosis and diffuse otosclerosis were associated with better functional results compared to the obliterative pattern (p < 0.05). Mean post-operative Air-Bone Gap was significantly higher in the 0.4 mm, compared to 0.6 mm piston group at 0.5 kHz (p < 0.001) and 1 kHz (p < 0.02); in the stapedotomy group a statistically significant difference was found between 0.4 and 0.6 mm piston groups, in favour of the latter (p < 0.05). No differences were encountered in terms of average hearing threshold and complications. Intra-operative variables cannot be fully predictable and our data could help in stratification of the results and as a landmark for the surgeon’s decisions

Low-temperature thin film encapsulation for MEMS with silicon nitride/chromium cap

In this work, a low-temperature fabrication process of thin film encapsulation (TFE) with silicon nitride/chromium cap is proposed for large-size (750 μm x 300 μm) packaging of microelectromechanical systems (MEMS). A FEM model was developed to evaluate the shape of TFE as a function of the residual stress and the thickness of the sealing layer, providing useful guidelines for the fabrication process. The low temperature of 200 °C, which was used in the plasma-enhanced chemical vapor deposition of the silicon nitride capping layer, allowed an organic sacrificial material to be employed for the definition of the encapsulation area. Silicon nitride/chromium (1 μm/20 nm) bilayer was demonstrated to be successful to overcome the technological limitations that affect the creation of cap holes with size of ~2 μm on high topography substrates, as in the case of MEMS. Plasma focused ion beam (PFIB) and scanning electron microscopy (SEM) techniques were used in combination to gain deeper insight into the sealing process of cap holes. Specifically, a PFIB-SEM serial section procedure was developed, resulting to be a powerful tool to directly observe the sealing profile above cap holes. Hence, the presented results greatly contribute to overcome the main technological/reliability issues of TFE, paving the way for the widespread application of the proposed encapsulation methodology to the most used MEMS devices, as radio-frequency (RF) switches, transducers, actuators, sensors and resonators

Investigation of the Effects of Autorotative Flare Index Variation on Helicopter Flight Dynamics in Autorotation

Autorotation is a flight condition whereby the engine of a helicopter is no longer supplying power to the main rotor system, which is driven solely by the upward flow of the air moving through the rotor. For helicopters, autorotation is a common emergency procedure performed by pilots to safely land the vehicle in the event of a power failure or tail-rotor failure. In the classic analysis of dynamic stability of helicopters in powered flight, it is common practice to neglect the effect of variation of rotor angular velocity, as the rotorspeed is constant. However, this assumption is no longer justified in case of autorotative flight. Therefore, the rotorspeed becomes an additional degree-of-freedom in autorotation, giving rise to a new stability mode that couples with classical rigid-body modes. The present paper aims at understanding the role of the rotorspeed degree-of-freedom in modifying the stability characteristics in autorotation of rotor systems with different autorotative flare indexes. Results show that the helicopter dynamics are considerably affected in autorotation as a consequence of the fact that the rotorspeed degree of freedom couples with the heave subsidence mode. Therefore, autorotation requires a different control strategy by the pilot and should not be mistakenly considered only as an energy management task. Furthermore, the autorotative flare index, used to characterize the autorotative performance during the preliminary design phase of a new helicopter, provides only energy information. Indeed, this paper demonstrates that high values of this index, representative of good autorotative performance in terms of available energy over required energy, may lead to degraded stability characteristics of the helicopter in autorotation.Control & Simulatio

Tinnitus revival during COVID‑19 lockdown: how to deal with it?

To the Editor, The novel Coronavirus Disease, officially designated as COVID-19 by the WHO, is a serious issue for public health. To contain the COVID-19, the Italian Government stated on March 9th 2020 the prohibition of any movement throughout the national area unless for work/health reasons and the obligation to remain as much as possible inside one’s own home. With the start of the so-called “Phase Two” on May 4th 2020, circulation within the same region was allowed again, due to the progressive slowdown of the outbreak. Therefore, since lockdown measures were relaxed and access to the emergency room or ENT clinic became less worrying for patients, specialists of Otolaryngology Units in Bari (Italy) observed an increase in the amount of subjects complaining of the revival of intense tinnitus. We attempt in this letter to focus on patients affected by chronic subjective tinnitus, that already had a diagnosis and self-stabilized without a massive treatment. Research studies have reported tinnitus wide impact on quality of life of subjects experiencing it, involving their emotional state, concentration and sleep quality; at this regard, Tinnitus Handicap Inventory (THI) is a self-reported tool regularly used to quantify the grade of perceived handicap as slight (0–16), mild (18–36), moderate (38–56), severe (58–76) or catastrophic (78–100) on the basis of 25 questions [1]. During the past 2 weeks, we have collected data from 16 patients among our population of chronic sufferers: THI observed was moderate in 62.5% and severe in 18.75% of cases, catastrophic in 12.5% and mild in 6.25% of subjects. Interestingly, the grade of handicap resulted increased by one-level in 12 out of 16 patients (75%); in particular, THI shifted from mild to moderate in 9 patients and from moderate to severe in 3 patients. As shown in the literature, tinnitus generation, maintenance and recrudescence are still debated. A cortical reorganization secondary to sensory deprivation has been proposed as one on the most frequent cause of tinnitus [2]. The avoidance of silence and acoustic masking have been proposed as effective measures to overcome sensory deprivation and increase masking of the symptom [3]. It is reasonable to think that, during the lockdown, the absence of environmental masking sounds from everyday life may have enhanced the tinnitus perception. Furthermore, proneness to worry and incoming stress during pandemic could be included as further potential risk factors for tinnitus worsening. As proficiently reviewed in a recent work [4], some internet/smartphone-based applications provide in tinnitus patients adequate counseling and interactive information together with sound therapy. As brain networks implicated in adaptive responses to sound stimuli and to worry are shared in many cases, an early decrease of anxiety status may release neural resources crucial for tinnitus habituation/distress perception [5]. In general, interactive platforms have been widely implemented during lockdown period due to the forced lack of real personal and working relationships; since smart-working seems to be successful for future plans, the development of smart applications and mobile services in the health care field may be promising in terms of cost-effectiveness, tolerability and simplicity of use