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Background and objective: Chronic respiratory diseases in children deteriorate their daily life due to dyspnea and reduced lung function. We aimed to evaluate the feasibility of home-based pulmonary rehabilitation in pediatric chronic respiratory diseases. Methods: This prospective, single-arm, cohort study included children with chronic lung disease. They were instructed to perform home-based pulmonary rehabilitation 30 min/session, three sessions/week for three months. Pulmonary function test (PFT) using spirometry, respiratory muscle strength (RMT), cardiopulmonary exercise test (CPET), 6 min walk test (6MWT), dyspnea questionnaires, speech evaluation, and pediatric quality of life inventory (PedsQL) were assessed pre- and post-pulmonary rehabilitation. Compliance and satisfaction of the program were also evaluated. Results: Twenty children (mean age: 11.2 ± 3.1 years) with chronic respiratory diseases without cardiopulmonary instability participated. The overall compliance was 71.1% with no related adverse events. After pulmonary rehabilitation, forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), RMT, 6MWT, dyspnea questionnaire, speech rate, and PedsQL (child) significantly improved (p < 0.05), particularly better in the FEV1 < 60% group than in the FEV1 ≥ 60% group and in the high-compliance group (compliance ≥ 50%) than in the low-compliance group (compliance < 50%). Conclusions: Home-based pulmonary rehabilitation for children with chronic lung disease was feasible with high compliance and effective in terms of objective functions, subjective dyspnea symptom, and quality of life.

For patients with severe burns that consist of contractures induced by fibrous scar tissue formation, a graft must adhere completely to the wound bed to enable wound healing and neovascularization. However, currently available grafts are insufficient for scar suppression owing to their nonuniform pressure distribution in the wound area. Therefore, considering the characteristics of human skin, which is omnidirectionally stretched via uniaxial stretching, we proposed an auxetic skin scaffold with a negative Poisson’s ratio (NPR) for tight adherence to the skin scaffold on the wound bed site. Briefly, a skin scaffold with the NPR effect was fabricated by creating a fine pattern through 3D printing. Electrospun layers were also added to improve adhesion to the wound bed. Fabricated skin scaffolds displayed NPR characteristics (−0.5 to −0.1) based on pulling simulation and experiment. Finger bending motion tests verified the decreased marginal forces (95%) of the scaffold comprising rarely dead cells and their spindle-shaped morphologies revealed the high cytocompatibility of the developed scaffold. Overall, the developed skin scaffold may help reduce wound strictures in the joints of patients with burns as it exerts less pressure on the wound margin.

Sarcopenia is the degenerative loss of skeletal muscle mass and function associated with aging and occurs in the absence of any underlying disease or condition. A comparison of the age-related molecular signaling signatures of different muscles has not previously been reported. In this study, we compared the age-related molecular signaling signatures of the intercostal muscles, the diaphragm, and the gastrocnemii using 6-month and 20-month-old rats. The phosphorylation of Akt, ribosomal S6, and Forkhead box protein O1 (FoxO1) in diaphragms significantly increased with age, but remained unchanged in the intercostal and gastrocnemius muscles. In addition, ubiquitin-proteasome degradation, characterized by the levels of MuRF1 and Atrogin-1, did not change with age in all rat muscles. Interestingly, an increase in LC3BII and p62 levels marked substantial blockage of autophagy in aged gastrocnemii but not in aged respiratory muscles. These changes in LC3BII and p62 levels were also associated with a decrease in markers of mitochondrial quality control. Therefore, our results suggest that the age-related signaling events in respiratory muscles differ from those in the gastrocnemii, most likely to preserve the vital functions played by the respiratory muscles.

Echocardiography is a medical examination that uses ultrasound to assess and diagnose the structure and function of the cardiac. Through the use of ultrasound waves, this examination allows medical professionals to create visualizations of the cardiac muscle, enabling them to diagnose and monitor conditions such as cardiac diseases, abnormalities, and functional disorders. An echocardiogram plays a crucial role in the early detection and diagnosis of various cardiac issues such as hypertension, myocardial infarction, valvular cardiac disease, and myocardial hypertrophy. It significantly contributes to determining treatment and management strategies. To achieve accurate disease diagnosis and develop appropriate treatment plans through echocardiography, it is essential to have a thorough understanding of proper probe usage, the precise acquisition of echocardiographic images, and the ability to interpret various echocardiographic examinations such as two-dimensional, M-mode, Doppler, etc. To enhance the skills required for echocardiography, medical educational institutions conduct theoretical classes, practical sessions using patient models, and clinical practice sessions with actual patients. However, issues such as inadequate practical adaptation due to theory-centric education, limitations in practical opportunities due to insufficient practice equipment, ethical or safety concerns arising during clinical practice, and a lack of educators leading to insufficient feedback, are currently being encountered. Hence, there is a need for new educational methods that can address the existing challenges in echocardiography education. In this paper, as part of these efforts, we propose a virtual reality-based immersive simulator for practical echocardiography training. The proposed echocardiography simulator allows users to explore a virtual echocardiography examination space by wearing a head-mounted display (HMD). This simulator consists of 3D virtual space models, interactive models manipulated by interaction devices, and 3D patient models containing normal or abnormal anatomical cardiac models. Using interactive devices such as HMD controllers and haptic devices, users can manipulate 3D models related to echocardiography within the simulator and interact with 3D patient models containing normal or abnormal anatomical cardiac models, allowing for the practice of echocardiography examinations. Ultimately, a performance evaluation of the developed immersive virtual reality simulator and usability validation targeting medical university students were conducted. The evaluation and validation results confirmed the potential efficacy of the proposed echocardiography VR simulator.

Vein blood sampling is a method of mass blood sampling that involves drawing blood from a vein for blood type discrimination, confirmation of various physiological indicators, disease diagnosis, etc.; it is the most commonly used blood sampling method. An important aspect of vein blood sampling is the search for the exact location of the vein for insertion of the syringe to draw blood. This is influenced by obesity as well as skin and blood vessel conditions in the patient and the experience of the clinical technologist, nurse, and resident who performs the blood sampling. Frequent practice is required to effectively perform blood sampling techniques. However, due to the many limitations of the practice room or laboratory, there is a problem of using only a limited environment and model for clinical practice. As a result, many medical educational institutions have situations in which only fragmentary clinical practices are performed, and it is difficult to practice many blood sampling skills, so they do not provide enough experience to understand the actual skill field. In this paper, we propose a virtual-reality-based vein blood sampling simulator that allows the practice of blood sampling techniques without limitation. The proposed vein blood sampling simulator can operate a 3D model related to vein blood sampling using an HMD controller and a haptic device in a virtual space for vein blood sampling practice by wearing an HMD (head-mounted display). Vein blood sampling can also be practiced through interaction with the patient 3D model. In addition, the effectiveness of a simulator developed for dental students was verified, and as a result of the verification, the potential of the proposed vein blood sampling simulator was confirmed.

In metal product manufacturing, additive manufacturing (AM) is a method that has the advantage of fabricating complex shapes and customized production, unlike existing machining methods. However, owing to the characteristics of the AM process, anisotropy of macrostructure occurs because of various causes such as the scan direction, melting, fusion, and cooling of the powdered material. The macrostructure anisotropy is realized from the scan direction, and when a single layer is stacked in one direction, it is expressed as orthogonal anisotropy. Here, the classical lamination theory is applied to simply calculate the individual orthotropic layers by superimposing them. Through this, the authors analyzed whether the mechanical properties of the product are isotropically expressed with a periodic layer rotation strategy. To determine if the mechanical properties can be reasonably considered to be isotropic, a shock absorber mount for a vehicle was manufactured by AM. The tensile and vibration test performed on the product was compared with the finite element analysis and experimental results. As a result of the comparison, it was confirmed that the macroscopically of the product was considered isotropic as the load-displacement diagram and the fracture location coincided, as well as the natural frequency and mode shape.

One of the factors that influence the dynamic characteristics of machining systems is the cutting tool. Cutting tools are very diverse, and receptance coupling substructure analysis (RCSA) is essential for analyzing the dynamic characteristics of each tool. For RCSA, a full receptance matrix of the equipment and tools is essential. In this study, rotational degree-of-freedom receptance was estimated and analyzed using translational receptance. Displacement/moment receptance was analyzed according to the distance of the response point using the first-and second-order finite difference methods. The rotation/moment receptance was estimated according to the distance of the response point. Rotation/moment receptance was analyzed using Schmitz’s method and compensation strategies. The limitations of these strategies were analyzed, and the rotation/moment receptance for the beam under free-free boundary conditions was predicted using the second compensation strategy.