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1.
Dalton Trans ; 53(7): 2922-2928, 2024 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-38284239

RESUMEN

The viscoelastic damping of nanocomposites reinforced with BNNTs and CNTs was compared. MD simulations revealed that the interfacial damping of pristine-CNT was superior to that of pristine-BNNT. The contrasting effects of structural defects were elucidated using interfacial adhesion, interphase, and overlapping phonon density of states in the nanotubes and polymers.

2.
Korean J Orthod ; 54(1): 48-58, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38072448

RESUMEN

Objective: : To quantify the effects of midline-related landmark identification on midline deviation measurements in posteroanterior (PA) cephalograms using a cascaded convolutional neural network (CNN). Methods: : A total of 2,903 PA cephalogram images obtained from 9 university hospitals were divided into training, internal validation, and test sets (n = 2,150, 376, and 377). As the gold standard, 2 orthodontic professors marked the bilateral landmarks, including the frontozygomatic suture point and latero-orbitale (LO), and the midline landmarks, including the crista galli, anterior nasal spine (ANS), upper dental midpoint (UDM), lower dental midpoint (LDM), and menton (Me). For the test, Examiner-1 and Examiner-2 (3-year and 1-year orthodontic residents) and the Cascaded-CNN models marked the landmarks. After point-to-point errors of landmark identification, the successful detection rate (SDR) and distance and direction of the midline landmark deviation from the midsagittal line (ANS-mid, UDM-mid, LDM-mid, and Me-mid) were measured, and statistical analysis was performed. Results: : The cascaded-CNN algorithm showed a clinically acceptable level of point-to-point error (1.26 mm vs. 1.57 mm in Examiner-1 and 1.75 mm in Examiner-2). The average SDR within the 2 mm range was 83.2%, with high accuracy at the LO (right, 96.9%; left, 97.1%), and UDM (96.9%). The absolute measurement errors were less than 1 mm for ANS-mid, UDM-mid, and LDM-mid compared with the gold standard. Conclusions: : The cascaded-CNN model may be considered an effective tool for the auto-identification of midline landmarks and quantification of midline deviation in PA cephalograms of adult patients, regardless of variations in the image acquisition method.

3.
Arch Pharm Res ; 47(1): 20-39, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38151648

RESUMEN

Ocular diseases are a growing global concern and have a significant impact on the quality of life. Cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy are the most prevalent ocular diseases. Their prevalence and the global market size are also increasing. However, the available pharmacotherapy is currently limited. These diseases share common pathophysiological features, including neovascularization, inflammation, and/or neurodegeneration. Histone deacetylases (HDACs) are a class of enzymes that catalyze the removal of acetyl groups from lysine residues of histone and nonhistone proteins. HDACs are crucial for regulating various cellular processes, such as gene expression, protein stability, localization, and function. They have also been studied in various research fields, including cancer, inflammatory diseases, neurological disorders, and vascular diseases. Our study aimed to investigate the relationship between HDACs and ocular diseases, to identify a new strategy for pharmacotherapy. This review article explores the role of HDACs in ocular diseases, specifically focusing on diabetic retinopathy, age-related macular degeneration, and retinopathy of prematurity, as well as optic nerve disorders, such as glaucoma and optic neuropathy. Additionally, we explore the interplay between HDACs and key regulators of fibrosis and angiogenesis, such as TGF-ß and VEGF, highlighting the potential of targeting HDAC as novel therapeutic strategies for ocular diseases.


Asunto(s)
Retinopatía Diabética , Glaucoma , Degeneración Macular , Recién Nacido , Humanos , Retinopatía Diabética/tratamiento farmacológico , Histona Desacetilasas/metabolismo , Calidad de Vida , Glaucoma/tratamiento farmacológico , Inhibidores de Histona Desacetilasas/farmacología , Inhibidores de Histona Desacetilasas/uso terapéutico , Inhibidores de Histona Desacetilasas/química
4.
Comput Methods Programs Biomed ; 242: 107853, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37857025

RESUMEN

BACKGROUND AND OBJECTIVE: Despite recent development of AI, prediction of the surgical movement in the maxilla and mandible by OGS might be more difficult than that of tooth movement by orthodontic treatment. To evaluate the prediction accuracy of the surgical movement using pairs of pre-(T0) and post-surgical (T1) lateral cephalograms (lat-ceph) of orthognathic surgery (OGS) patients and dual embedding module-graph convolution neural network (DEM-GCNN) model. METHODS: 599 pairs from 3 institutions were used as training, internal validation, and internal test sets and 201 pairs from other 6 institutions were used as external test set. DEM-GCNN model (IEM, learning the lat-ceph images; LTEM, learning the landmarks) was developed to predict the amount and direction of surgical movement of ANS and PNS in the maxilla and B-point and Md1crown in the mandible. The distance between T1 landmark coordinates actually moved by OGS (ground truth) and predicted by DEM-GCNN model and pre-existed CNN-based Model-C (learning the lat-ceph images) was compared. RESULTS: In both internal and external tests, DEM-GCNN did not exhibit significant difference from ground truth in all landmarks (ANS, PNS, B-point, Md1crown, all P > 0.05). When the accumulated successful detection rate for each landmark was compared, DEM-GCNN showed higher values than Model-C in both the internal and external tests. In violin plots exhibiting the error distribution of the prediction results, both internal and external tests showed that DEM-GCNN had significant performance improvement in PNS, ANS, B-point, Md1crown than Model-C. DEM-GCNN showed significantly lower prediction error values than Model-C (one-jaw surgery, B-point, Md1crown, all P < 0.005; two-jaw surgery, PNS, ANS, all P < 0.05; B point, Md1crown, all P < 0.005). CONCLUSION: We developed a robust OGS planning model with maximized generalizability despite diverse qualities of lat-cephs from 9 institutions.


Asunto(s)
Mandíbula , Procedimientos Quirúrgicos Ortognáticos , Humanos , Cefalometría/métodos , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Procedimientos Quirúrgicos Ortognáticos/métodos , Maxilar/diagnóstico por imagen , Maxilar/cirugía
5.
Cartilage ; : 19476035231199442, 2023 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-37698092

RESUMEN

OBJECTIVE: Treatment strategies for osteochondral defects, for which particulated autologous cartilage transplantation (PACT) is an emerging treatment strategy, aim to restore the structure and function of the hyaline cartilage. Herein, we compared the efficacy of PACT with control or human transforming growth factor-ß (rhTGF-ß), and clarified the necessity of bone graft (BG) with PACT to treat shallow osteochondral defects in a porcine model. DESIGN: Two skeletally mature male micropigs received 4 osteochondral defects in each knee. The 16 defects were randomized to (1) empty control, (2) PACT, (3) PACT with BG, or (4) rhTGF-ß. Animals were euthanized after 2 months and histomorphometry, immunofluorescence analysis, semiquantitative evaluation (O'Driscoll score), and magnetic resonance observation of cartilage repair tissue (MOCART) score were performed. RESULTS: Hyaline cartilages, glycosaminoglycan synthesis, and collagen type II staining were more abundant in the PACT than in the control and rhTGF-ß groups. The O'Driscoll score was significantly different between groups (P < 0.001), with both PACT groups showing superiority (P = 0.002). PACT had the highest score (P = 0.002), with improved restoration of subchondral bone compared with PACT with BG. The MOCART score showed significant differences between groups (P = 0.021); MOCART and O'Driscoll scores showed high correlation (r = 0.847, P < 0.001). CONCLUSION: Treatment of osteochondral defects with PACT improved tissue quality compared with that with control or rhTGF-ß in a porcine model. BG, in addition to PACT, may be unnecessary for shallow osteochondral defects. Clinical Relevance. BG may not be necessary while performing PACT.

6.
Biomater Res ; 26(1): 73, 2022 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-36471437

RESUMEN

Until recent, there are no ideal small diameter vascular grafts available on the market. Most of the commercialized vascular grafts are used for medium to large-sized blood vessels. As a solution, vascular tissue engineering has been introduced and shown promising outcomes. Despite these optimistic results, there are limitations to commercialization. This review will cover the need for extrusion-based 3D cell-printing technique capable of mimicking the natural structure of the blood vessel. First, we will highlight the physiological structure of the blood vessel as well as the requirements for an ideal vascular graft. Then, the essential factors of 3D cell-printing including bioink, and cell-printing system will be discussed. Afterwards, we will mention their applications in the fabrication of tissue engineered vascular grafts. Finally, conclusions and future perspectives will be discussed.

7.
Arch Craniofac Surg ; 23(4): 171-177, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36068692

RESUMEN

BACKGROUND: The treatment of zygoma complex fractures is of crucial importance in the field of plastic surgery. However, surgical methods to correct zygoma complex fractures, including the number of fixation sites, differ among operators. Although several studies have compared two-point and three-point fixation, no comparative research has yet been conducted on one-point versus two-point fixation using computed tomography scans of surgical results. Therefore, the present study aimed to address this gap in the literature by comparing surgical results between one-point and two-point fixation procedures. METHODS: In this study, we randomly selected patients to undergo surgery using one of two surgical methods. We analyzed patients with unilateral zygoma complex fractures unaccompanied by other fractures according to whether they underwent one-point fixation of the zygomaticomaxillary buttress or two-point fixation of the zygomaticomaxillary buttress and the zygomaticofrontal suture. We then made measurements at three points-the zygomaticofrontal suture, inferior orbital wall, and malar height-using 3-month postoperative computed tomography images and performed statistical analyses to compare the results of the two methods. RESULTS: All three measurements (zygomaticofrontal suture, inferior orbital wall, and malar height) showed significant differences (p < 0.05) between one-point and two-point fixation. Highly significant differences were found for the zygomaticofrontal suture and malar height parameters. The difference in the inferior wall measurements was less meaningful, even though it also reached statistical significance. CONCLUSION: Using three parameters in a statistical analysis of imaging findings, this study demonstrated significant differences in treatment outcomes according to the number of fixations. The results indicate that bone alignment and continuity can be achieved to a greater extent by two-point fixation instead of one-point fixation.

8.
Clin Exp Ophthalmol ; 50(9): 1047-1056, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36073108

RESUMEN

BACKGROUND: To determine the prevalence and risk factors of epiretinal membrane (ERM) utilising spectral-domain optical coherence tomography (SD-OCT). METHODS: We investigated data from the 2017 to 2018 Korea National Health and Nutrition Examination Survey. Individuals aged ≥40 years with readable fundus photographs and SD-OCT results were included. ERM was diagnosed by fundus photography and OCT. The following data was collected: demographics, health interview, health examination, and nutritional survey results. The prevalence of ERM was estimated and risk factors for ERM were analysed. RESULTS: A total of 6807 participants were finally included. Adjusted prevalence of ERM was 7.0% (95% confidence interval, 6.3%-7.8%). Multivariate logistic regression analysis revealed that age ≥ 50 years (p < 0.001 for all age groups), history of cataract surgery (p < 0.001), well-controlled hypertension (p = 0.006), and diabetic retinopathy (p = 0.041) were risk factors for ERM. CONCLUSIONS: The estimated prevalence of ERM was 7.0%, which was higher than that of previous reports using fundus photography only in an East Asian population. Possible risk factors for ERM were older age, history of cataract surgery, hypertension, and diabetic retinopathy.


Asunto(s)
Catarata , Retinopatía Diabética , Membrana Epirretinal , Oftalmopatías , Hipertensión , Humanos , Membrana Epirretinal/diagnóstico , Membrana Epirretinal/epidemiología , Retinopatía Diabética/diagnóstico , Prevalencia , Encuestas Nutricionales , Tomografía de Coherencia Óptica , Factores de Riesgo , Estudios Retrospectivos
9.
Comput Biol Med ; 148: 105914, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35961089

RESUMEN

Landmark detection in flatfoot radiographs is crucial in analyzing foot deformity. Here, we evaluated the accuracy and efficiency of the automated identification of flatfoot landmarks using a newly developed cascade convolutional neural network (CNN) algorithm, Flatfoot Landmarks AnnoTating Network (FlatNet). A total of 1200 consecutive weight-bearing lateral radiographs of the foot were acquired. The first 1050 radiographs were used as the training and tuning, and the following 150 radiographs were used as the test sets, respectively. An expert orthopedic surgeon (A) manually labeled ground truths for twenty-five anatomical landmarks. Two orthopedic surgeons (A and B, each with eight years of clinical experience) and a general physician (GP) independently identified the landmarks of the test sets using the same method. After two weeks, observers B and GP independently identified the landmarks once again using the developed deep learning CNN model (DLm). The X- and Y-coordinates and the mean absolute distance were evaluated. The average differences (mm) from the ground truth were 0.60 ± 0.57, 1.37 ± 1.28, and 1.05 ± 1.23 for the X-coordinate, and 0.46 ± 0.59, 0.97 ± 0.98, and 0.73 ± 0.90 for the Y-coordinate in DLm, B, and GP, respectively. The average differences (mm) from the ground truth were 0.84 ± 0.73, 1.90 ± 1.34, and 1.42 ± 1.40 for the absolute distance in DLm, B, and GP, respectively. Under the guidance of the DLm, the overall differences (mm) from the ground truth were enhanced to 0.87 ± 1.21, 0.69 ± 0.74, and 1.24 ± 1.31 for the X-coordinate, Y-coordinate, and absolute distance, respectively, for observer B. The differences were also enhanced to 0.74 ± 0.73, 0.57 ± 0.63, and 1.04 ± 0.85 for observer GP. The newly developed FlatNet exhibited better accuracy and reliability than the observers. Furthermore, under the FlatNet guidance, the accuracy and reliability of the human observers generally improved.


Asunto(s)
Pie Plano , Pie , Humanos , Redes Neurales de la Computación , Reproducibilidad de los Resultados , Soporte de Peso
10.
Front Plant Sci ; 12: 693854, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34489997

RESUMEN

Dietary supplements of anthocyanin-rich vegetables have been known to increase potential health benefits for humans. The optimization of environmental conditions to increase the level of anthocyanin accumulations in vegetables during the cultivation periods is particularly important in terms of the improvement of agricultural values in the indoor farm using artificial light and climate controlling systems. This study reports on the measurement of variations in anthocyanin accumulations in leaf tissues of four different cultivars in Brassica rapa var. chinensis (bok choy) grown under the different environmental conditions of the indoor farm using hyperspectral imaging. Anthocyanin accumulations estimated by hyperspectral imaging were compared with the measured anthocyanin accumulation obtained by destructive analysis. Between hyperspectral imaging and destructive analysis values, no significant differences in anthocyanin accumulation were observed across four bok choy cultivars grown under the anthocyanin stimulation environmental condition, whereas the estimated anthocyanin accumulations displayed cultivar-dependent significant differences, suggesting that hyperspectral imaging can be employed to measure variations in anthocyanin accumulations of different bok choy cultivars. Increased accumulation of anthocyanin under the stimulation condition for anthocyanin accumulation was observed in "purple magic" and "red stem" by both hyperspectral imaging and destructive analysis. In the different growth stages, no significant differences in anthocyanin accumulation were found in each cultivar by both hyperspectral imaging and destructive analysis. These results suggest that hyperspectral imaging can provide comparable analytic capability with destructive analysis to measure variations in anthocyanin accumulation that occurred under the different light and temperature conditions of the indoor farm. Leaf image analysis measuring the percentage of purple color area in the total leaf area displayed successful classification of anthocyanin accumulation in four bok choy cultivars in comparison to hyperspectral imaging and destructive analysis, but it also showed limitation to reflect the level of color saturation caused by anthocyanin accumulation under different environmental conditions in "red stem," "white stem," and "green stem." Finally, our hyperspectral imaging system was modified to be applied onto the high-throughput plant phenotyping system, and its test to analyze the variation of anthocyanin accumulation in four cultivars showed comparable results with the result of the destructive analysis.

11.
Small ; 17(20): e2100438, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33817966

RESUMEN

The highly selective detection of trace gases using transparent sensors at room temperature remains challenging. Herein, transparent nanopatterned chemiresistors composed of aligned 1D Au-SnO2 nanofibers, which can detect toxic NO2 gas at room temperature under visible light illumination is reported. Ten straight Au-SnO2 nanofibers are patterned on a glass substrate with transparent electrodes assisted by direct-write, near-field electrospinning, whose extremely low coverage of sensing materials (≈0.3%) lead to the high transparency (≈93%) of the sensor. The sensor exhibits a highly selective, sensitive, and reproducible response to sub-ppm levels of NO2 , and its detection limit is as low as 6 ppb. The unique room-temperature NO2 sensing under visible light emanates from the localized surface plasmonic resonance effect of Au nanoparticles, thereby enabling the design of new transparent oxide-based gas sensors without external heaters or light sources. The patterning of nanofibers with extremely low coverage provides a general strategy to design diverse compositions of gas sensors, which can facilitate the development of a wide range of new applications in transparent electronics and smart windows wirelessly connected to the Internet of Things.

12.
Regen Biomater ; 8(2): rbab001, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33738115

RESUMEN

Among many biomaterials, gelatin methacrylate (GelMA), a photocurable protein, has been widely used in 3D bioprinting process owing to its excellent cellular responses, biocompatibility and biodegradability. However, GelMA still shows a low processability due to the severe temperature dependence of viscosity. To overcome this obstacle, we propose a two-stage temperature control system to effectively control the viscosity of GelMA. To optimize the process conditions, we evaluated the temperature of the cooling system (jacket and stage). Using the established system, three GelMA scaffolds were fabricated in which different concentrations (0, 3 and 10 wt%) of silanated silica particles were embedded. To evaluate the performances of the prepared scaffolds suitable for hard tissue regeneration, we analyzed the physical (viscoelasticity, surface roughness, compressive modulus and wettability) and biological (human mesenchymal stem cells growth, western blotting and osteogenic differentiation) properties. Consequently, the composite scaffold with greater silica contents (10 wt%) showed enhanced physical and biological performances including mechanical strength, cell initial attachment, cell proliferation and osteogenic differentiation compared with those of the controls. Our results indicate that the GelMA/silanated silica composite scaffold can be potentially used for hard tissue regeneration.

13.
Sensors (Basel) ; 21(2)2021 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-33435556

RESUMEN

We present a novel simultaneous localization and mapping (SLAM) system that extends the state-of-the-art ORB-SLAM2 for multi-camera usage without precalibration. In this system, each camera is tracked independently on a shared map, and the extrinsic parameters of each camera in the fixed multi-camera system are estimated online up to a scalar ambiguity (for RGB cameras). Thus, the laborious precalibration of extrinsic parameters between cameras becomes needless. By optimizing the map, the keyframe poses, and the relative poses of the multi-camera system simultaneously, observations from the multiple cameras are utilized robustly, and the accuracy of the shared map is improved. The system is not only compatible with RGB sensors but also works on RGB-D cameras. For RGB cameras, the performance of the system tested on the well-known EuRoC/ASL and KITTI datasets that are in the stereo configuration for indoor and outdoor environments, respectively, as well as our dataset that consists of three cameras with small overlapping regions. For the RGB-D tests, we created a dataset that consists of two cameras for an indoor environment. The experimental results showed that the proposed method successfully provides an accurate multi-camera SLAM system without precalibration of the multi-cameras.

14.
Orthod Craniofac Res ; 24(1): 111-120, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32741117

RESUMEN

OBJECTIVE: The objective of this study was to compare the resistance to sliding of aesthetic orthodontic coated wires after prolonged water immersion for up to 4 weeks. SETTING AND SAMPLE POPULATION: An in vitro study of commercially available orthodontic appliances. MATERIALS AND METHODS: Aesthetic coated stainless-steel wires (Parylene-coated, epoxy-coated and Teflon-coated) (0.019" × 0.025") and an uncoated control were immersed in distilled-deionized water for zero, two or four weeks at 37°C and then were subjected to resistance-to-sliding tests through a three-bracket system of sapphire ceramic brackets (0.022" × 0.028" slot) and clear-coloured elastic ligatures at a contact angle of 0° or 3°. Maximal and average resistance to sliding was analysed by a three-way analysis of variance, two general linear models and a post hoc Tukey's honest significant difference test. RESULTS: Water immersion time, contact angle, wire group and their interactions had statistically significant effects on the resistance to sliding of tested orthodontic wires. Various coated wires had distinct timely changes in the maximal and average resistance to sliding after water immersion for 2 to 4 weeks. When compared to the uncoated control in most of the experimental conditions, epoxy-coated wires had lower or non-significant differences in resistance to sliding, while Parylene-coated wire had higher resistances. CONCLUSIONS: Prolonged water immersion for weeks alters the resistance to sliding of aesthetic orthodontic wires coated with Parylene, epoxy or Teflon. Based on their resistance to sliding, different designs in orthodontic biomechanics should be considered for the different aesthetic orthodontic coated wires.


Asunto(s)
Soportes Ortodóncicos , Alambres para Ortodoncia , Aleaciones Dentales , Estética Dental , Fricción , Inmersión , Ensayo de Materiales , Níquel , Diseño de Aparato Ortodóncico , Acero Inoxidable , Propiedades de Superficie , Titanio , Agua
15.
Work ; 67(1): 157-164, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32986639

RESUMEN

BACKGROUND: The philosophy of universal design contributes to providing age-friendly products and environments in the ageing society. OBJECTIVE: The purpose of this study is to establish the philosophy of universal safety and design to ensure the safety and health of product users and production workers. METHODS: The concept and principles of universal safety and design are developed based on the limitations of universal design and the necessity of a new philosophy. RESULTS: Requirements of physical support, flexibility, accessibility, ensuring safety and health, diversity and inclusion, and sustainability are proposed for implementing the universal safety and design philosophy. Also, the guidelines for applying the universal safety and design philosophy are presented. CONCLUSIONS: The principles presented in this study can be applied to reduce incidents and ensure productivity in customers and production workers by helping them to work efficiently, comfortably, and safely.


Asunto(s)
Salud Laboral , Diseño Universal , Humanos , Filosofía
16.
Adv Mater ; 32(51): e2002075, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32930431

RESUMEN

Artificial olfaction based on gas sensor arrays aims to substitute for, support, and surpass human olfaction. Like mammalian olfaction, a larger number of sensors and more signal processing are crucial for strengthening artificial olfaction. Due to rapid progress in computing capabilities and machine-learning algorithms, on-demand high-performance artificial olfaction that can eclipse human olfaction becomes inevitable once diverse and versatile gas sensing materials are provided. Here, rational strategies to design a myriad of different semiconductor-based chemiresistors and to grow gas sensing libraries enough to identify a wide range of odors and gases are reviewed, discussed, and suggested. Key approaches include the use of p-type oxide semiconductors, multinary perovskite and spinel oxides, carbon-based materials, metal chalcogenides, their heterostructures, as well as heterocomposites as distinctive sensing materials, the utilization of bilayer sensor design, the design of robust sensing materials, and the high-throughput screening of sensing materials. In addition, the state-of-the-art and key issues in the implementation of electronic noses are discussed. Finally, a perspective on chemiresistive sensing materials for next-generation artificial olfaction is provided.


Asunto(s)
Nariz Electrónica , Semiconductores , Gases/química
17.
Opt Express ; 28(18): 26870-26881, 2020 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-32906953

RESUMEN

In this study, a double-ring erbium-doped fiber (EDF) laser with an optical switch and a fiber Bragg grating (FBG)-referenced interrogating system was developed and demonstrated. This double-ring configuration can achieve high power amplified spontaneous emission, enabling laser oscillation even within the L-band. The output range and signal-to-noise ratio (SNR) of the double-ring EDF laser were measured to be 1512-1610 nm and 55 dB. In addition, the interrogating system using FBGs for reference resulted in precision improvement of ∼25 pm over those achieved in previous studies, reaching a precision of about 7 pm. The high power, broad tuning range, and sufficiently high precision of the proposed interrogating system make it promising for use in FBG-based sensing applications.

18.
Sci Rep ; 10(1): 11403, 2020 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-32647270

RESUMEN

Thermal perception is essential for the survival and daily activities of people. Thus, it is desirable to realize thermal feedback stimulation for improving the sense of realism in virtual reality (VR) for users. For thermal stimulus, conventional systems utilize liquid circulation with bulky external sources or thermoelectric devices (TEDs) on rigid structures. However, these systems are difficult to apply to compact wearable gear used for complex hand motions to interact with VR. Furthermore, generating a rapid temperature difference, especially cooling, in response to a thermal stimulus in real-time is challenging for the conventional systems. To overcome this challenge and enhance wearability, we developed an untethered real-time thermal display glove. This glove comprised piezoelectric sensors enabling hand motion sensing and flexible TEDs for bidirectional thermal stimulus on skin. The customized flexible TEDs can decrease the temperature by 10 °C at room temperature in less than 0.5 s. Moreover, they have sufficiently high durability to withstand over 5,000 bends and high flexibility under a bending radius of 20 mm. In a user test with 20 subjects, the correlation between thermal perception and the displayed object's color was verified, and a survey result showed that the thermal display glove provided realistic and immersive experiences to users when interacting with VR.

19.
Sensors (Basel) ; 20(7)2020 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-32235532

RESUMEN

This paper presents a wearable hand module which was made of five fiber Bragg grating (FBG) strain sensor and algorithms to achieve high accuracy even when worn on different hand sizes of users. For real-time calculation with high accuracy, FBG strain sensors move continuously according to the size of the hand and the bending of the joint. Representatively, four algorithms were proposed; point strain (PTS), area summation (AREA), proportional summation (PS), and PS/interference (PS/I or PS/I_α). For more accurate and efficient assessments, 3D printed hand replica with different finger sizes was adopted and quantitative evaluations were performed for index~little fingers (77 to 117 mm) and thumb (68~78 mm). For index~little fingers, the optimized algorithms were PS and PS/I_α. For thumb, the optimized algorithms were PS/I_α and AREA. The average error angle of the wearable hand module was observed to be 0.47 ± 2.51° and mean absolute error (MAE) was achieved at 1.63 ± 1.97°. These results showed that more accurate hand modules than other glove modules applied to different hand sizes can be manufactured using FBG strain sensors which move continuously and algorithms for tracking this movable FBG sensors.


Asunto(s)
Técnicas Biosensibles , Dedos/anatomía & histología , Mano/anatomía & histología , Dispositivos Electrónicos Vestibles , Algoritmos , Humanos , Impresión Tridimensional
20.
Int J Occup Saf Ergon ; 26(3): 497-506, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29722612

RESUMEN

This study aimed to describe the characteristics of occupational injuries of female workers in residential healthcare facilities for the elderly, and to analyze human errors as causes of accidents. From the national industrial accident compensation data, 506 female injuries were analyzed by age and occupation. The results showed that medical service worker was the most prevalent (54.1%), followed by social welfare worker (20.4%). Among injuries, 55.7% had <1 year of work experience and 37.9% were aged ≥60 years. Slips/falls were the most common type of accident (42.7%), and the proportion injured by slips/falls increases with age. Among human errors, action errors were the primary reasons, followed by perception errors and cognition errors. In addition, the ratios of injuries by perception errors and action errors increase with age. The findings of this study suggest that there is a need to design workplaces that accommodate the characteristics of older female workers.


Asunto(s)
Accidentes de Trabajo/estadística & datos numéricos , Ergonomía , Traumatismos Ocupacionales/epidemiología , Accidentes por Caídas/estadística & datos numéricos , Adulto , Factores de Edad , Femenino , Hogares para Ancianos/estadística & datos numéricos , Humanos , Persona de Mediana Edad , Traumatismos Ocupacionales/etiología , República de Corea , Factores de Riesgo , Indemnización para Trabajadores/estadística & datos numéricos
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