Volume 68, Issue 6

Proximal humeral shaft fractures can be treated with helically deformed bone plates to reduce the risk of iatrogenic nerve lesion. Controversially to this common surgical technique that was first established in 1999, no biomechanical investigation on humeral helical plating is recorded by other reviews, which focus on proximal fractures exclusively. Does an additional scope for shaft fractures reveal findings of helical testing? The present systematic literature review was performed based on guidelines by Kitchenham et al. to systematically search and synthesize literature regarding biomechanical testing of osteosynthetic systems for proximal humeral shaft fractures. Therefore, a systematic approach to search and screen literature was defined beforehand and applied on the findings of the database PubMed ® . Synthesized information of the included literature was categorized, summarized and analyzed via descriptive statistics. Out of 192 findings, 22 publications were included for qualitative synthesis. A wide range of different test methods was identified, leading to a suboptimal comparability of specific results between studies. Overall, 54 biomechanical test scenarios were identified and compared. Physiological based boundary conditions (PB-BC) were referenced in 7 publications only. One study of testing straight and helical dynamic compression plates without PB-BCs was identified, showing significant differences under compressional loading. The absence of test standards of specific fields like humeral fractures lead to a high variance in biomechanical testing of osteosynthetic locking plates for proximal humeral shaft fractures. Physiological approaches offer realistic test scenarios but need to be uniformed for enhanced comparability between studies. The impact of helically deformed locking plates under PB-BC was not identified in literature.

This study aims compare the spatiotemporal and kinematic running parameters obtained by the WalkerView (Tecnobody, Bergamo, Italy) with those recorded by a optoelectronic 3D motion capture system. Seventeen participants were simultaneously recorded by the WalkerView and a motion capture system during running tests on the WalkerView at two different speeds (i.e., 8 km/h and 10 km/h). Per each parameter and speed the Root Mean Square Error (RMSE), the intraclass correlation coefficient (ICC), and the mean of the difference (MOD) and limits of agreement (LOAs) indexes obtained from Bland-Altman analysis were used to compare the two systems. ICCs show an excellent agreement for the mean step time and the cadence at both testing speeds (ICC=0.993 at 8 km/h; ICC=0.998 at 10 km/h); a lower agreement was found for all the kinematic variables. Small differences for some spatio-temporal parameters and greater differences for the kinematic variables were found. Therefore, WalkerView could represent a practical, accessible, and less expensive tool for clinicians, researchers, and sports trainers to assess the characteristics spatio-temporal parameters of running in non-laboratory settings.

Objectives Tunnel enlargement and graft failure are common complications associated with ACL reconstruction. The mechanical interaction between the graft and the tunnel aperture may play a more important role. This study aims to evaluate graft position within femoral tunnel and the graft force under external loads. Methods An FE model of the femur-graft-tibia complex was constructed from CT images of an anatomically reconstructed knee specimen. The model was subjected to kinematics of passive flexion extension, anterior/posterior translation, internal/external rotation and valgus kinematics, which were collected from experimental testing. Graft shift and rotation of graft-tunnel contact region during flexion/extension and external loadings were recorded and compared to experimental measurements. Results Model showed that the graft shifted in the femoral tunnel during flexion and under external loads. The graft-tunnel contact area rotated by up to 55° during flexion from full extension to 90° of extension implying that the so-called “wiper effect” occurs during most of flexion angles. Conclusions Different regions of the femoral tunnel aperture, particularly the anterior region, were under significantly more contact force from the graft than other areas of the aperture during the anterior translation test, potentially leading to femoral tunnel enlargement to the anterior side of the aperture.

Objectives The aim of the present study was to assess the biomechanical behaviour of using a posterior implant design with inclined shoulder designs in all-on-four treatment via three-dimensional finite element analysis. Methods Implants with standard and inclined shoulder designs were modelled for posterior implants. Implants were positioned into the maxilla and mandible models according to the all-on-four concept. Compressive stresses in the peri-implant bone, the von Mises stresses in the different components of the prosthetic restoration, and movement of the prosthesis were obtained. Results The compressive stresses of the models with inclined shoulder design resulted in 15–58 % decrease compared with standard shoulder design. The von Mises stresses in the posterior implants reduced 18–47 %, stresses in the implant body increased 38–78 %, stresses in the abutment screw reduced 20–65 %, stresses in the framework of prosthesis reduced 1–18 % and deformation of the prosthesis was reduced 6–37 % in the models of inclined shoulder design compared with models of standard shoulder design. The compressive and von Mises stresses were generally higher in the mandible models than in the maxilla models for standard and inclined shoulder designs. Conclusions All evaluated components of the simulated treatment except for posterior abutment bodies showed better biomechanical behaviour with inclined shoulder design. The clinical success of all-on-four treatment maybe enhanced by using posterior implants with an inclined shoulder design.

Objectives Dental composite materials for filling teeth are usually hardened by polymerisation lamps emitting blue light. However, the same wavelength is also emitted by light of dental operating lamps for lighting the oral cavity. Thus, the hardening of the composite is already initiated earlier, shortening the time of formability. The objective of this study is to develop a specific white LED for dental operating lamps. When restoring teeth, it enables dentists to work longer on light-curing composites in the same brightness. Methods Based on a short-wave blue coloured LED and a fluorescent substance, a white luminescent LED with a colour temperature of approx. 3,000 K is produced as a prototype. The formable working times of three composites are measured for this LED and two dental head lamps at an illuminance of 10,000 lx. Results Shorter working times of 98–237 s were measured for the headlamps and 409–807 s for the new LED. This light of the new LED is perceived by the human eye as warm white. Conclusions The new LED extends the working time by the factor of 3.0 to 5.8 compared to the head lamps. This enables more precise modelling of fillings.

Objectives Together with the corneoscleral shell the intraocular pressure maintains the shape of the human eyeball and thus ensures both mechanical and optical integrity, whereby the relationship between the intraocular volume and pressure is described by the so-called ocular compliance. The compliance of the human eye is of significance in situations where a variation of the intraocular volume leads to a change in pressure or vice versa, as this is the case in many clinical settings. In order to provide a framework and set-up for experimental investigations and testing this paper presents a bionic inspired approach to simulate the ocular compliance by using elastomeric membranes – based on physiological behaviour. Methods For parameter studies and for validation, the numerical analysis with hyperelastic material models shows good agreement with reported compliance curves. In addition, the compliance curves of six different elastomeric membranes have been measured. Results The results show that the characteristics of the compliance curve of the human eye can be modeled within a 5 % range using the proposed elastomeric membranes. Conclusions A set-up for experimental investigations is presented that allows the simulation of the compliance curve of the human eye without simplifications in terms of shape, geometry, and deformation behaviour.

Objectives Diabetic foot ulcers (DFU) can be avoided if symptoms of diabetic foot complications are detected early and treated promptly. Early detection requires regular examination, which might be limited for many reasons. To identify affected or potentially affected regions in the diabetic plantar foot, the region-wise severity of the plantar foot must be known. Methods A novel thermal diabetic foot dataset of 104 subjects was developed that is suitable for Indian healthcare conditions. The entire plantar foot thermogram is divided into three parts, i.e., forefoot, midfoot, and hindfoot. The division of plantar foot is based on the prevalence of foot ulcers and the load on the foot. To classify the severity levels, conventional machine learning (CML) techniques like logistic regression, decision tree, KNN, SVM, random forest, etc., and convolutional neural networks (CNN), such as EfficientNetB1, VGG-16, VGG-19, AlexNet, InceptionV3, etc., were applied and compared for robust outcomes. Results The study successfully developed a thermal diabetic foot dataset, allowing for effective classification of diabetic foot ulcer severity using the CML and CNN techniques. The comparison of different methods revealed variations in performance, with certain approaches outperforming others. Conclusions The region-based severity analysis offers valuable insights for targeted interventions and preventive measures, contributing to a comprehensive assessment of diabetic foot ulcer severity. Further research and development in these techniques can enhance the detection and management of diabetic foot complications, ultimately improving patient outcomes.

In this study, we present a new method for acquiring human vital signs using a Range-Doppler matrix (RDM) of FMCW radar data and a Gaussian interpolation algorithm (GIA). First, the RDM is derived by applying a two-dimensional fast Fourier transform (2D-FFT) to the radar data, and the GIA is applied in the Doppler dimension to estimate the target velocity signal. Subsequently, a robust enhanced trend filtering (RETF) algorithm is used to eliminate the large-scale body motion from the vital signs. Finally, the time-varying filter-based empirical mode decomposition (TVF-EMD) algorithm is employed to extract the respiratory and heartbeat intrinsic mode functions (IMFs), which are filtered according to their respective spectral power to obtain the respiratory and heartbeat frequencies. The proposed method was evaluated using vital signs data collected from seven volunteers (4 males and 3 females) with Texas Instrument’s AWR1642, and the results were compared with data from a reference monitor. The experiments showed that the method had an accuracy of 93 % for respiration and 95 % for heart rate in the presence of random body movements. Unlike traditional radar-based vital signs detection methods, this approach does not rely on range bin selection of the range profile matrix (RPM), thereby avoiding phase wrap problems and producing more accurate results. Currently, research in this field is limited.

Adults with coronary artery disease often have atherosclerosis, this is defined as the accumulation of plaque in the tissues of the arterial wall. Cardiologists utilize optical coherence tomography (OCT), a light-based imaging method, to examine the layers of intracoronary tissue along pathological formations, such as plaque accumulation. Intracoronary cross-sectional images produced by state-of-the-art catheter-based imaging scheme have 10–15 µm high resolution. Nevertheless, interpretation of the obtained images depends on the operator, which takes a lot of time and is exceedingly error-prone from one observer to another. OCT image post-processing that automatically and accurately tags coronary plaques can help the technique become more widely used and lower the diagnostic error rate. To overcome these problems, Atherosclerosis plaque tissue classification using Self-Attention-Based Conditional Variational Auto-Encoder Generative Adversarial Network (APC-OCTPI-SACVAGAN) is proposed which classifies the Atherosclerosis plaque images as Fibro calcific plaque, Fibro atheroma, Thrombus, Fibrous plaque and Micro-vessel. The proposed APC-OCTPI-SACVAGAN technique is executed in MATLAB. The efficiency of proposed APC-OCTPI-SACVAGAN method attains 16.19 %, 17.93 %, 19.81 % and 1.57 % higher accuracy; 16.92 %, 11.54 %, 5.29 % and 1.946 % higher Area under curve; and 28.06 %, 25.32 %, 32.19 % and 39.185 % lower computational time comparing to the existing methods respectively.

Transthoracic impedance is one of the key factors affecting the success of defibrillation. Impedance compensation technique is used to adjust defibrillation parameters according to the transthoracic impedance of the defibrillator. In this paper, a combined impedance compensation strategy is proposed to address the shortcomings of existing compensation strategies. In order to evaluate the performance of the combined compensation strategy, this paper uses the prototype as the experimental machine, and uses two AED with representative impedance compensation strategies as the control machine, and the simulated defibrillation method is used for comparative testing. The results show that the combined impedance compensation has a more steadier distribution over the defibrillation energy and current: compared with the energy-based impedance compensation strategy, this strategy can significantly reduce the peak current (25 Ω: 27.8 vs. 54.7 A; 50 Ω: 20.7 vs. 32.3 A) and average current (25 Ω: 24.8 vs. 37.5 A) of defibrillation at low impedance, and compared with the current impedance compensation strategy, it can significantly reduce the defibrillation energy (150 Ω: 8.6 vs. 1.7 %, 175 Ω: 15.6 vs. 4.9 %, 200 Ω: 21.9 vs. 8.5 %) at high impedance. Impedance compensation is more precise and the current passing during defibrillation is steadier.