Biomedizinische Technik. Biomedical engineering最新文献

Objectives: Contaminated apparatus and surgical tools pose serious health risks. For such purpose, disinfection chambers are employed. However, these systems rely on mercury-based UV lamps which comes with various drawbacks. These limitations have driven interest in Ultraviolet-C Light Emitting Diode (UV-C LED) technology as a safer and more efficient alternative. However, existing studies have not thoroughly explored the impact of varying intensities of pulse width modulation (PWM) on disinfection efficacy.

Methods: To addess this, the present study designed and tested a LED-based disinfection chamber by employing 4-W 275 nm Surface Mount Device (SMD) LEDs against frequently isolated bacteria. By following prior approach, irradiation time was alternated at 30-s intervals and antibacterial efficacy was assessed through various parameters. Additionally, scanning electron microscopy (SEM) was performed to examine the morphological changes.

Results: Results indicated that the reduction was significantly influenced (p<0.05) with varying PWM levels (60-100 %), achieving 2.05-log₁₀ and 1.54-log₁₀ inactivation against Escherichia coli and Staphylococcus aureus, respectively, upon exposure to 51.24 mJ/cm² under maximum exposure settings. Moreover, complete cellular damage leading to bleb protrusion and cell-leakage confirmed the disruption of bacterial DNA.

Conclusions: In conclusion, UV-LEDs show great potential for disinfection, with efficiency influenced by PWM and dosage.

Objectives: The objective of this study was to evaluate the sealing ability of the implant-abutment interface in a specific implant system in comparison to other implant systems under conditions of increasing dynamic loading.

Methods: Three different implants and four abutment types were tested: one implant with a conical abutment connection, one implant with a flat abutment connection, and one implant with an abutment switch feature and two different abutment connections. The tests consisted of a phase of cyclic loading followed by a leakage test. The maximum loading force was increased, and the procedure was repeated, until either the implant-abutment connection failed, or a leakage was detected. Loading criteria were modified based on the ISO standard 14801:2016.

Results: The conical implant abutment connections exhibited fracture prior to leakage at varying failure forces and loading cycles, whereas the platform abutment type showed leakage or fracture at a relatively low force. The two different abutment types used on the same implant system showed extremely different results.

Conclusions: Literature shows similar high chewing forces mostly only for healthy subjects. For patients with dental implants, leakage is still preferable to fracture. In conclusion, the test showed that some implants with a conical abutment are more resistant to leakage and may be preferable if higher chewing forces are expected.

Objectives: The electrical bioimpedance (EBI) technique has been used to measure gastric motility and emptying parameters. A well-known technique for this purpose is electrogastrography (EGG). No correlation between EGG signal and mechanical motility has been reported. In this study, a direct data comparison of these two techniques was performed.

Methods: 23 volunteers underwent simultaneous gastric monitoring using EGG and EBI. Signal processing was performed to isolate the slow waves of 0.5-9 cpm. The parameters obtained from 70 % overlapped time slots of 3.5 min, included the dominant frequency and power of the normo-gastric region and the percentage of brady-, normo-, and tachy-gastric slow waves.

Results: The EGG showed slightly higher values in dominant frequencies, whereas EBI displayed higher variability. High-frequency features were more significant in the EBI, with lower variability, and correlations were found in approximately half of the frequency spectra. Slow waves exhibited poor correlation, but were significant at 95 % of the timeslots.

Conclusions: Comparing EBI and EGG, global parameters in the normogastric region had slight variances, which may not significantly impact clinical findings. The sensitivity of the EBI to higher frequencies is evident.

Objectives: This study evaluates how research output and impact in medical informatics vary among EU member states before and during the COVID-19 pandemic by analyzing publication volume, impact metrics, collaboration patterns, and open-access trends. It seeks to identify regional disparities, highlight key research themes, and provide insights for researchers, the public, and policymakers to promote equitable access, collaboration, and investment in medical informatics across the EU.

Methods: A bibliometric analysis was performed using Clarivate Web of Science and InCites databases, encompassing 6,620 articles from 47 medical informatics journals published between 2018 and 2022. Metrics such as cumulative impact factors, article counts, and collaboration trends were analyzed.

Results: Our analysis identified substantial regional disparities in research output and impact. Western European countries, including Germany, the Netherlands, and Spain, consistently led in article volume and cumulative impact factors, while Eastern European countries showed lower engagement. Collaboration metrics revealed that 66 % of publications involved international partnerships, showcasing strong cross-border cooperation within the EU.

Conclusions: This study highlights the uneven distribution of research productivity in medical informatics across the EU. The findings underline the importance of international partnerships and equitable access to research in advancing medical informatics and addressing evolving healthcare challenges.

Objectives: The aim of the present study was to investigate, whether polyetherketoneketone (PEKK) secondary crowns could be considered as alternative to gold standard in terms of their physical properties and manufacturing costs.

Methods: An upper jaw model with six implants was used. Frameworks with either 6 PEKK- or 6 electroplated secondary crowns were cemented in a wear simulator. A total of 20 specimens (10 PEKK, 10 gold) run 10,000 cycles in the wear simulator with a lubricant. Additionally, 10,000 cycles in the thermocycling baths with 5 °C and 55 °C have gone through, before running extra 10,000 cycles in the wear simulator again. Finally, the abutments were analysed for signs of wear under the electron microscope.

Results: The mean pulling out force value for PEKK was 21 N. For the electroplated gold secondary crowns an average of 19 N was measured. Multiple fluctuations were observed in the gold series of tests. After 20,000 cycles in the wear simulator and 10,000 cycles in the thermocycling machine, there were no major losses to be measured in terms of wear for both materials. In the microscopic analysis of the abutments, traces of wear could be seen in pull-out direction, mainly in the gold samples.

Conclusions: PEKK secondary crowns have lower costs, more stable retention force values and are easier to produce than the gold standard. On average, the pull-out force values were 11 N higher than recommended.

Globally, the prevalence of stroke is significant and increasing annually. This growth has led to a demand for rehabilitation services that far exceeds the supply, leaving many stroke survivors without adequate rehabilitative care. In response to this challenge, this study introduces a portable exoskeleton system that integrates neural control mechanisms governing human arm movements. This design leverages neuroplasticity principles to simulate natural movements, aiming to reactivate and strengthen neuromuscular connections and thus enhance rehabilitation outcomes. A tailored musculoskeletal model of the human arm and an associated cost function were developed to accurately replicate the planar motion trajectories of a healthy human arm across 32 directions. The application of a Proportional-Derivative (PD) controller enables precise tracking of these trajectories by the exoskeleton. Individual testing has demonstrated high consistency between the exoskeleton-driven motion paths and the simulated trajectories, especially in trajectory accuracy along the X and Y axes. These findings support the efficacy of integrating advanced neural control strategies with practical exoskeleton designs in stroke rehabilitation.

Objectives: The shape is commonly used to describe the objects. State-of-the-art algorithms in medical imaging are predominantly diverging from computer vision, where voxel grids, meshes, point clouds, and implicit surface models are used. This is seen from the growing popularity of ShapeNet (51,300 models) and Princeton ModelNet (127,915 models). However, a large collection of anatomical shapes (e.g., bones, organs, vessels) and 3D models of surgical instruments is missing.

Methods: We present MedShapeNet to translate data-driven vision algorithms to medical applications and to adapt state-of-the-art vision algorithms to medical problems. As a unique feature, we directly model the majority of shapes on the imaging data of real patients. We present use cases in classifying brain tumors, skull reconstructions, multi-class anatomy completion, education, and 3D printing.

Results: By now, MedShapeNet includes 23 datasets with more than 100,000 shapes that are paired with annotations (ground truth). Our data is freely accessible via a web interface and a Python application programming interface and can be used for discriminative, reconstructive, and variational benchmarks as well as various applications in virtual, augmented, or mixed reality, and 3D printing.

Conclusions: MedShapeNet contains medical shapes from anatomy and surgical instruments and will continue to collect data for benchmarks and applications. The project page is: https://medshapenet.ikim.nrw/.

Objectives: One of the primary causes of the women death is breast cancer. Accurate and early breast cancer diagnosis plays an essential role in its treatment. Computer Aided Diagnosis (CAD) system can be used to help doctors in the diagnosis process. This study presents an efficient method to performance improvement of the breast cancer diagnosis CAD system using thermal images.

Methods: The research strategy in the proposed CAD system is using efficient algorithms in feature extraction and classification phases, and new efficient feature selection algorithm. In the feature extraction phase, the Segmentation Fractal Texture Analysis (SFTA) algorithm that is a texture analysis algorithm is used.This algorithm utilizes two-threshold binary decomposition. In the feature selection phase, the developed feature selection algorithm, which is hybrid of binary grey wolf optimization algorithm and firefly optimization algorithm, is applied to extracted features. Then, the kNN, SVM, and DTree classification techniques are applied to check whether the selected features are efficiently discriminated the group successfully with minimal misclassifications.

Results: The DMR database is utilized for performance evaluation of the proposed method. The results indicate that the obtained accuracy, specificity, sensitivity, and MCC are 97, 96, 98, and 94.17 %, respectively.

Conclusions: The developed breast cancer diagnosis method has advantages compared to other breast cancer diagnosis using thermal images.

Objectives: Helical plating is an established method for treating proximal humeral shaft fractures, mitigating the risk of iatrogenic radial nerve damage. However, biomechanical test data on helical plates under physiological load condition is limited. Hence, the aim of this study was to compare the biomechanical performance of helical and straight PHILOS^® Long plates in AO12C2 fractures using static and cyclic implant system testing.

Methods: Helical and straight PHILOS^® Long plates on artificial bone substitutes were tested under physiological axial static (n=6) and cyclic loading (n=12). The axial construct stiffness was the main parameter for comparing the biomechanical performance of the two groups. Mimicking a clinical scenario, the helical deformation was performed consecutively by an experienced surgeon using iron bending tools. The torsional angle was determined computationally from 3D-scanning models afterwards.

Results: Helical plating resulted in a significantly reduced axial construct stiffness in all test scenarios compared to conventional straight plating (static testing: p=0.012; cyclic testing: p≤0.010). No failure occurred within the range of physiological loading in both groups.

Conclusions: Helical plating favors multidimensional deformation of the test sample in lateral-ventral direction under axial loading, resulting in a reduced axial construct stiffness and in an increased interfragmentary movement. No biomechanical failure is to be expected within physiological load boundaries.