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Biomedizinische Technik. Biomedical Engineering

Nikolai Blanik, Konrad Heimann, Carina Pereira, Michael Paul, Vladimir Blazek, Boudewijn Venema, Thorsten Orlikowsky, Steffen Leonhardt
Vital parameter monitoring of term and preterm infants during incubator care with self-adhesive electrodes or sensors directly positioned on the skin [e.g. photoplethysmography (PPG) for oxygen saturation or electrocardiography (ECG)] is an essential part of daily routine care in neonatal intensive care units. For various reasons, this kind of monitoring contains a lot of stress for the infants. Therefore, there is a need to measure vital parameters (for instance respiration, temperature, pulse, oxygen saturation) without mechanical or conductive contact...
October 15, 2016: Biomedizinische Technik. Biomedical Engineering
Andreas Heinrich, Felix V Güttler, Florian Schlesies, René Aschenbach, Niklas Eckardt, Ulf K-M Teichgräber
PURPOSE: The purpose of this study was to measure artifacts and visibility of lumen for modern and most commonly used stents in vascular interventions according to a standardized test method of the American Society for Testing and Materials (ASTM). MATERIALS AND METHODS: Twenty-four peripheral self-expanding nitinol stents and three stainless steel stents with diameters between 5 and 8 mm and lengths between 30 and 250 mm from seven different manufacturers were compared on a 1...
October 14, 2016: Biomedizinische Technik. Biomedical Engineering
Cui Tan, Xiaoxu Zhang, Qing Li
Two major problems with magnesium (Mg) alloy biomaterials are the poor corrosion resistance and infection associated with implantation. In this study, a novel calcium phosphate (CaP)/tetracycline (TC) composite coating for Mg implants that can both improve the corrosion resistance of Mg and release a drug in a durable way is reported. Scanning electron microscope (SEM) images showed that TC additives make the CaP coating more compact and uniform. Electrochemical tests indicated CaP/TC coatings can provide excellent corrosion protection for Mg alloy substrates...
October 8, 2016: Biomedizinische Technik. Biomedical Engineering
Linda Tran, Khosrow Mottaghy, Sabine Arlt-Körfer, Christian Waluga, Mehdi Behbahani
Undesirable thrombotic reactions count among the most frequent and serious complications for patients who rely on the use of medical devices. To improve the design of medical devices, it is essential to develop a more precise understanding of platelet reactions. Clinical studies and experiments have shown a strong dependence of platelet deposition behavior on the flow. However, today the influence of hemodynamic parameters such as the shear rate on thrombotic reactions is not well understood. For the study of the shear-dependent mechanisms leading to the activation, adhesion and aggregation of platelets, a Couette flow system was used to investigate thrombocyte behavior with regard to well-defined flow conditions at shear-rate values between γ˙=400 $\dot \gamma = {\rm{400}}$ and 1400 1/s...
October 8, 2016: Biomedizinische Technik. Biomedical Engineering
Sascha Princz, Ulla Wenzel, Hanna Tritschler, Silke Schwarz, Christian Dettmann, Nicole Rotter, Martin Hessling
An automated bioreactor system for three-dimensional (3D) cultivation of facial cartilage replacement matrices (e.g. whole human auricles) with automatised medium exchange, gas flow and temperature control was developed. The measurement of O2 saturation and pH value in the medium was performed with a non-invasive optical method. The whole system can be observed via remote monitoring worldwide. First results demonstrated that the complete system remained sterile throughout a period of 42 days. Human chondrocytes migrated into the employed cartilage replacement matrix consisting of decellularised porcine nasoseptal cartilage (pNSC)...
October 4, 2016: Biomedizinische Technik. Biomedical Engineering
Antoine Vaesken, Christian Pidancier, Nabil Chakfe, Frederic Heim
Transcatheter aortic valve implantation (TAVI) is nowadays a popular alternative technique to surgical valve replacement for critical patients. Biological valve tissue has been used in these devices for over a decade now with over 100,000 implantations. However, material degradations due to crimping for catheter insertion purpose have been reported, and with only 6-year follow-up, no information is available about the long-term durability of biological tissue. Moreover, expensive biological tissue harvesting and chemical treatment procedures tend to promote the development of synthetic valve leaflet materials...
September 22, 2016: Biomedizinische Technik. Biomedical Engineering
Zheng Ma, Tianshuang Qiu
When we examine the event-related potential (ERP) responses of Donchin's brain-computer interface (BCI) speller, a type of quasi-periodic fluctuation (FLUC) overlapping with the ERP components can be observed; this fluctuation is traditionally treated as interference. However, if the FLUC is detectable in a working BCI, it can be used for asynchronous control, i.e. to indicate whether the BCI is under the control state (CS) or under the non-control idle state (NC). Asynchronous control is an important issue to address to enable BCI's practical use...
September 21, 2016: Biomedizinische Technik. Biomedical Engineering
Benjamin Kienast, Hellal Mohsen, Robert Wendlandt, Nils Reimers, Arndt P Schulz, Hinrich Heuer, Justus Gille, Hanjo Neumann
BACKGROUND: Osteochondral injuries often lead to osteoarthritis of the affected joint. All established systems for refixation of osteochondral defects show certain disadvantages. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants, a more secure anchoring is assumed. MATERIALS AND METHODS: The aim of the study was to investigate if ultrasound-activated pins can provide secure fixation of osteochondral fragments compared to screws and conventional resorbable pins...
September 2, 2016: Biomedizinische Technik. Biomedical Engineering
Claudia Wittkowske, Stefan Raith, Maximilian Eder, Alexander Volf, Jan S Kirschke, Benjamin König, Christoph Ihle, Hans-Günther Machens, Stefan Döbele, Laszlo Kovacs
A semi-automated workflow for evaluation of diaphyseal fracture treatment of the femur has been developed and implemented. The aim was to investigate the influence of locking compression plating with diverse fracture-specific screw configurations on interfragmentary movements (IFMs) with the use of finite element (FE) analysis. Computed tomography (CT) data of a 22-year-old non-osteoporotic female were used for patient specific modeling of the inhomogeneous material properties of bone. Hounsfield units (HU) were exported and assigned to elements of a FE mesh and converted to mechanical properties such as the Young's modulus followed by a linear FE analysis performed in a semi-automated fashion...
August 30, 2016: Biomedizinische Technik. Biomedical Engineering
Rahul Khare, Branislav Jaramaz
After a knee replacement procedure, postoperative radiological assessment is carried out to evaluate outcome and predict procedure success. For this assessment, long-standing load-bearing antero-posterior radiographs are used to carry out manual identification of anatomic landmarks. These landmarks are subsequently used to estimate leg alignment. The positions of the landmarks in the radiographs are affected by the patient pose and the X-ray projection center. Although there is some past work exploring the impact of patient pose on the landmarks in the radiographs, there is no previous work on the impact of the X-ray projection center on the estimated leg alignment...
August 29, 2016: Biomedizinische Technik. Biomedical Engineering
Sanaz Mosafer Khoorjestan, Gholamreza Rouhi, Karamollah Toolabi
How the distance of sutures from the edge of tissue and the horizontal distance between stitches affect the mechanical strength of anastomosis is investigated. In this study, 180 bovine intestines were used to investigate the optimum pattern in 18 groups by considering a 4, 6, and 8 mm horizontal distance between stitches, and a 3, 5, and 7 mm distance from the edge of tissue with 3-0 Silk and 3-0 PDS sutures to maximize the strength of anastomosis (10 specimens in each group). Also, 80 specimens were used to investigate the maximum effective distance of sutures from the edge of tissue in eight groups of: 3, 5, 7, and 10 mm distance from the edge, with the same type of sutures...
August 17, 2016: Biomedizinische Technik. Biomedical Engineering
Seonhong Hwang, Yen-Sheng Lin, Nathan S Hogaboom, Lin-Hwa Wang, Alicia M Koontz
Wheelchair propulsion is a major cause of upper limb pain and injuries for manual wheelchair users with spinal cord injuries (SCIs). Few studies have investigated wheelchair turning biomechanics on natural ground surfaces. The purpose of this study was to investigate the relationship between tangential push force and linear velocity of the wheelchair during the turning portions of propulsion. Using an instrumented handrim, velocity and push force data were recorded for 25 subjects while they propel their own wheelchairs on a concrete floor along a figure-eight-shaped course at a maximum velocity...
August 17, 2016: Biomedizinische Technik. Biomedical Engineering
Vijay Mahadeo Mane, D V Jadhav
Diabetic retinopathy (DR) is the most common diabetic eye disease. Doctors are using various test methods to detect DR. But, the availability of test methods and requirements of domain experts pose a new challenge in the automatic detection of DR. In order to fulfill this objective, a variety of algorithms has been developed in the literature. In this paper, we propose a system consisting of a novel sparking process and a holoentropy-based decision tree for automatic classification of DR images to further improve the effectiveness...
August 11, 2016: Biomedizinische Technik. Biomedical Engineering
Zhihong Mao, Dake Yi, Guo Cao
The purpose of this study is to discuss the influence of sizes of abutments and fixation screws on immediately loaded dental implants in mandibular bones using nonlinear finite element methods. Abutments with three unilateral wall thicknesses and fixation screws with three diameters are analyzed to compare the stresses and deformations under a vertical or oblique force of 130 N. The nonlinearity due to friction contacts between the fixation screw, the abutment, the implant, and the bone is taken into account...
August 11, 2016: Biomedizinische Technik. Biomedical Engineering
Christoph Arndt, Alexandra Görgner, Carsten Klöhn, Roger Scholz, Christian Voigt
As literature implies, daily activities of total hip arthroplasty (THA) patients may include movements prone to implant-implant impingement. Thus, high shear stresses may be induced at the acetabular implant-bone interface, increasing the risk of implant loosening. The aim of the current study is to determine whether or not impingement events may pose an actual risk to acetabular periprosthetic bone. An existing experimental workflow was augmented to cover complete three-dimensional strain gage measurement...
August 9, 2016: Biomedizinische Technik. Biomedical Engineering
Mathias Rebholz, Raffael Amacher, Anastasios Petrou, Mirko Meboldt, Marianne Schmid Daners
Ventricular assist devices (VADs) are mechanical blood pumps that are clinically used to treat severe heart failure. Pulsatile VADs (pVADs) were initially used, but are today in most cases replaced by turbodynamic VADs (tVADs). The major concern with the pVADs is their size, which prohibits full pump body implantation for a majority of patients. A reduction of the necessary stroke volume can be achieved by increasing the stroke frequency, while maintaining the same level of support capability. This reduction in stroke volume in turn offers the possibility to reduce the pump's overall dimensions...
August 9, 2016: Biomedizinische Technik. Biomedical Engineering
Ernst Hofer, Robert Arnold, Gernot Reishofer, Helmut Ahammer
No abstract text is available yet for this article.
September 1, 2016: Biomedizinische Technik. Biomedical Engineering
Fabian Braun, Alia Lemkaddem, Virginie Moser, Stephan Dasen, Olivier Grossenbacher
No abstract text is available yet for this article.
September 1, 2016: Biomedizinische Technik. Biomedical Engineering
Jörg Schröttner, Andreas Tilp, Robert Neubauer, Sigrid Ranner, Peter Grieshofer
No abstract text is available yet for this article.
September 1, 2016: Biomedizinische Technik. Biomedical Engineering
Natascha Bayer, Nino Hirnschall, Lukas Traxler, Andreas Drauschke, Oliver Findl
No abstract text is available yet for this article.
September 1, 2016: Biomedizinische Technik. Biomedical Engineering
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