Biomedical engineering advances最新文献

Hearing loss is a significant quality-of-life (QOL) issue in aging populations and is linked to social isolation, dementia, and depression. Early detection and treatment of hearing loss are critically important aspects of preventing cognitive decline and dementia. To date, smartphone, or tablet-based hearing test methods have been proposed to increase the rate of hearing loss detection outside of the hospital. However, simple hearing tests may be performed without adequate soundproofing facilities; therefore, the reliability of such tests in noisy environments is questionable. In this study, we propose a simple hearing test method that uses a soundproof active noise control (ANC) headphone with acoustic-filtering earcups. The ANC headphones provide sufficient soundproofing over a wide frequency range, and the acoustic-filtering earcups provide effective soundproofing around the test frequency. The proposed earcup is equipped with a Helmholtz resonator (HR) array, wherein multiple HRs are densely arrayed in a honeycomb structure. The muffling effect of the HRs effectively attenuated the noise at a specific frequency. This property is useful for high-accuracy hearing tests, in which the noise around the test frequency is sufficiently reduced. The prototype device attained a maximum noise attenuation of 50 dB at approximately 4 kHz and provided hearing tests that were as accurate as those obtained in a soundproof room.

The utilization of telemedicine significantly surged during COVID-19 pandemic. For both patients and physicians, this was a safe way to access and provide healthcare services. Remotely accessible medical devices play an integral part in delivery of these services. To understand the current status, this study dives into technological advancements of these telemedicine devices applied to surgery, diagnosis, monitoring and consultation during the last ten years. We present a comprehensive review of the telemedicine devices developed between 2012 and 2022. This article will enable the reader to identify the prevailing technologies, gaps that exist and the potential trend towards the development of telemedicine devices.

Noninvasive measurement of arterial pulse provides information about the heart condition through the evaluation of primary hemodynamic parameters such as blood pressure (BP), pulse rate (PR), and pulse regularity. Moreover, BP is one of the most important biomarkers of cardiovascular disease, mainly hypertension. To prevent this, accurate measurement of BP becomes necessary. Currently, flexible pressure sensors have drawn a lot of interest due to their prospective applications in wearable devices for healthcare monitoring. We have collected the human oscillometric pulse by a polymer-based flexible capacitive pressure sensor and calculated the BP as well as PR using the maximum amplitude algorithm. The results are compared with a pre-calibrated oscillometric BP monitor available in the market. Based on the error criteria, the device followed the universal standard. In addition, the flexibility and high accuracy of the device result in the assessment of the possible medical applications, including abnormal pulse rates such as tachycardia or bradycardia and irregular heart rhythm such as cardiac arrhythmia.

Experts require large high-resolution retinal images to detect tiny abnormalities, such as microaneurysms or issues of vascular branches. However, these images often suffer from low quality (e.g., resolution) due to poor imaging device configuration and misoperations. Many works utilized Convolutional Neural Network-based (CNN) methods for image super-resolution. The authors focused on making these models more complex by adding layers and various blocks. It leads to additional computational expenses and obstructs the application in real-life scenarios. Thus, this paper proposes a novel, lightweight, deep-learning super-resolution method for retinal images. It comprises a Vision Transformer (ViT) encoder and a convolutional neural network decoder. To our best knowledge, this is the first attempt to use a transformer-based network to solve the issue of accurate retinal image super-resolution. A progressively growing super-resolution training technique is applied to increase the resolution of images by factors of 2, 4, and 8. The prominent architecture remains constant thanks to the adaptive patch embedding layer, which does not lead to additional computational expense due to increased up-scaling factors. This patch embedding layer includes 2-dimensional convolution with specific values of kernel size and strides that depend on the input shape. This strategy has removed the need to append additional super-resolution blocks to the model. The proposed method has been evaluated through quantitative and qualitative measures. The qualitative analysis also includes vessel segmentation of super-resolved and ground truth images. Experimental results indicate that the proposed method outperforms the current state-of-the-art methods.

Tissue engineering strategies for tendon repair and regeneration rely heavily on the use of tendon derived cells. However, these cells frequently undergo phenotypic drift in vitro, which compromises their therapeutic potential. In order to maintain the phenotype of tendon derived cells in vitro, microenvironmental cues (biophysical, biochemical and/or biological in origin) have been used to better imitate the complex tendon microenvironment. Herein, the influence of planar and grooved (groove width of ∼1.0 µm, groove depth of ∼1.4 µm and distance between groves of ∼1.7 µm) poly(glycolide-co-ε-caprolactone) substrates with elastic modulus of 7 kPa and poly(lactide-co-trimethylene carbonate) substrates with elastic modulus of 12 kPa on human tendon derived cell response was assessed, using planar tissue culture plastic substrates of 3 GPa elastic modulus as control, in both basal and tenogenic media. At day 17, the grooved 12 kPa poly(lactide-co-trimethylene carbonate) substrate induced the highest deposition and alignment of collagen type I in tenogenic media. At day 17, the grooved 12 kPa poly(lactide-co-trimethylene carbonate) substrate and the tissue culture plastic induced the highest deposition and the tissue culture plastic and the planar 7 kPa poly(glycolide-co-ε-caprolactone) induced the lowest alignment of tenascin C in tenogenic media. Also at day 17 in tenogenic media, the grooved 12 kPa poly(lactide-co-trimethylene carbonate) substrate induced the upregulation of most tenogenic genes (COL1A1, COL3A1, MKX, TNMD). Our data further support the notion of multifactorial tissue engineering for effective control over cell fate in vitro setting.

Endovascular technologies such as percutaneous transluminal coronary angioplasty and stenting are widely used due to being minimally invasive procedures. One of the endovascular devices, a drug-eluting stent (DES), proved to be a safe and effective therapeutic option for cardiologists, substantially reducing in-stent restenosis (ISR) rates. DES consists of thin (< 200 µm) or ultra-thin (< 70 µm) struts made of Cobalt-Chromium (CoCr) or other alloys. The DES with ultra-thin struts exhibits higher longitudinal flexibility and improved trackability. It also reduces vascular injury and promotes more rapid endothelization, substantially decreasing the risk of ISR. This study evaluates comprehensive mechanical performances of two different structural designs of newly developed ultra-thin CoCr stents (i.e., strut width of 75 µm or 65 µm). These two stent designs are engineered with distinct bridge size and distribution patterns, prioritizing enhanced flexibility irrespective of the strut thickness. Computational modeling results show anticipated stress distribution with maximum local stresses, which are compared with experimental outcomes conducted in this study. ASTM guideline based in vitro experimental studies have been conducted to assess the stents’ longitudinal flexibility, radial strength, recoil and shortening, as well as crushability through this study. Three-point bending experiments have demonstrated that the stent design 1 requires less bending force compared to the design 2, showing better longitudinal flexibility of the stent design 1 in the collapsed state for the new ultra-thin DES devices. The design 1 also showed superior radial strength and recoiling phenomena, as well as smaller shortening. In short, the stent design 1 shows better mechanical performance needed for the coronary artery DES.