Springer Science and Business Media LLC

This study investigated the maximum insertion torque value (ITV) of different dimensions of orthodontic miniscrews for primary stability, and further explored the effects of continuous rotation insertion and intermittent rotation insertion methods on the stability of orthodontic miniscrews. Six different dimensions of orthodontic miniscrews, three lengths (6.0, 8.0, and 10.0 mm) and two diameters (1.4 and 1.6 mm), were inserted into the artificial bone specimens by using a torque testing machine, and continuous and intermittent rotation insertion methods were applied. There were a total of 12 groups, and each group was composed of five samples. The torque testing machine was used to record the maximum ITV and torque-time curve. The median maximum ITV of the orthodontic miniscrews in the 12 groups ranged between 11.5 and 23.7 N cm. In orthodontic miniscrews of 1.6 mm diameter, regardless of the insertion method, the ITV increased with length. For orthodontic miniscrews of 1.4 mm diameter, there was no statistical difference in the maximum ITV regardless of the inserted method as the differences in length were negligible (only 2.0 mm). Furthermore, there was no statistical difference in the maximum ITV required for the continuous rotation insertion and intermittent rotation insertion methods between inserting orthodontic miniscrews of similar dimensions. The maximum ITV mostly increased with the increase in the diameter or length of the orthodontic miniscrew. There was no statistical difference in the maximum ITV required for continuous rotation and intermittent rotation insertion methods.

Most image denoising methods process each noise-corrupted pixel from the top-left to the bottom-right of the images using a sliding window. By firstly processing a noise-corrupted pixel with plenty of noise neighbor pixels in a local window may deteriorate the quality of subsequent pixels, enabling the quality of the denoised image to be reduced. In this paper, we present a method to change the process order on noise-corrupted pixels to improve the performance of bio-image denoising according to the confidence measure. If the center pixel of a local window with a non-extreme gray value (the pixel value is neither 0 nor 255 for an 8-bit gray bio-image) represents a noise-free pixel, no processing is performed. Conversely, the gray level of the center pixel is modified by a restored value. Two confidence measures are used to determine the order of producing the restored value, including direction confidence and noise-free confidence. An analysis window both with a greater quantity of noise-free pixels and with a consistent pixel change direction is defined as a high confidence region which will be processed firstly. If the variation direction of a pixel is consistent with the neighbor pixels, directional mean filtering is performed. Conversely, median filtering is performed for the pixels with low confidence where the quantity of noise-free pixels is low in a local window or the directions of pixel changes are inconsistent. The experimental results show that the proposed method can further improve the performance of an image denoising method which utilizes the sliding window from the top-left to the bottom-right. The major reason is because of the prior restoration of the noise-corrupted pixels in high confidence regions. These restored pixels are subsequently employed to restore the noise-corrupted pixels with low confidence, resulting in the quality of restored bio-image being improved.

Many studies showed electrocardiogram (ECG) parameters are useful for predicting fatal ventricular arrhythmias (VAs). However, the studies have several shortcomings. Firstly, all studies lack of effective way to present behavior of various ECG parameters prior to the occurrence of the VAs. Secondly, they also lack of discussion on how to consider the parameters as abnormal. Thirdly, the reports do not include approaches to increase the detection accuracy for the abnormal patterns. The purpose of this study is to address the aforementioned issues. It identifies ten ECG parameters from various sources and then presents a review based on the identified parameters. From the review, it has been found that the increased risk of VAs can be represented by presence and certain abnormal range of the parameters. The variation of parameters range could be influenced by either gender or age. This study also has discovered the facts that averaging, outliers elimination and morphology detection algorithms can contribute to the detection accuracy.

Hip fracture has become a common health problem among old people. Understanding hip fracture mechanics is the first step to effectively prevent hip fracture. The objective of this study was to investigate the combined effect of reversed stress/strain patterns in femur (during single-leg stance and sideways fall) and the inhomogeneous material properties of femur bone. We constructed 40 subject-specific femur finite element models from medical quantitative computed tomography and used them to identify high risk regions in the femur induced by the two loading configurations. The obtained results showed that compared to the single-leg stance, in the sideways fall the highest stress and strain occurred at different locations; and the tensile-compressive stress status was also completely reversed. Previous studies have found that a bone has different strength at different anatomic sites, and at the same site it has different compressive and tensile strength. Our study suggested that, in addition to the large magnitude of impact force induced in falling, the abnormal stress/strain patterns produced by the non-habitual loading condition in falling may be another external contributor to hip fracture.

Atlantoaxial instability is a progressive cervical spine condition that often requires surgical intervention. The posterior C1-2 transarticular fixation has been a great advancement for the management of atlantoaxial instability as it provides improved biomechanical stability. However, the surgical risks of serious neurovascular injury associated with this technique remain an obstacle for its wider adoption. The goal of this study is to evaluate the surgical outcome of C1-2 transarticular screw fixation utilizing a lab-designed trajectory planning software (TPS) system and to investigate the likely kinematical impact of deviated screw trajectory. The TPS system was applied to 19 patients (mean age: 61.1 years, range: 35–71 years; 14 males and 5 females) that underwent C1-2 transarticular fixation at our institution. A total of 32 transarticular screws were inserted. Pre-operative computed tomography images were used to render a three-dimensional bone tissue model as well as the corresponding multi-planar digitally reconstructed radiographs. The pre- and post-operative positions of C1 and C2 were also compared. Overall, only one malpositioned screw was identified and no major complications occurred for any of the patients. A comparison of the planned and actual screw insertion trajectories indicated that the vertical angle was the only parameter to have a statistically significant difference. Moderate negative correlation was found between the vertical entry point and the vertical angle, and moderate positive correlation was found between the horizontal entry point and the horizontal angle. The TPS system is a cost-effective clinical implementation that can potentially reduce the associated complication rates for C1-2 transarticular fixation. The system should be viewed as a useful assistive device as well as a potential training and auditing tool for institutions where more expensive navigational systems are not readily available.

This study developed a speech recognition technique to detect wheezing. Wheezes are important in the diagnosis of pulmonary pathologies such as asthma. The acoustic features of wheezes are distinct in the frequency domain. Therefore, many studies have focused on detecting wheezing peaks in spectrograms through image processing. However, automated detection of wheezing peaks is difficult because of blurred edges and noise. This paper proposes an alternative approach for wheezing detection in which the mel frequency cepstral coefficients (MFCCs) are integrated into the Gaussian mixture model (GMM). The MFCCs reduce the short-term spectral information to a few coefficients, and the GMM recognizes the respiratory sounds. The respiratory sounds of 18 volunteers (9 asthmatic and 9 normal adults) were recorded for training and testing. The results of a qualitative analysis of wheeze recognition showed a good sensitivity of 0.881 and a high specificity of 0.995.

We developed a method to estimate the cross-sectional area (CSA) of the lower limb skeletal muscle using lower extremity circumference measured by a three-dimensional (3D) structured light scanner. 3D scanning data and magnetic resonance (MR) images of the lower extremities of 36 volunteers were collected. MR images of the lower extremities of 31 supplementary volunteers were also obtained. The CSA and circumference of the legs of the 36 volunteers were measured using 3D scanning and MR images. The measurements based on the 3D scanning and MR images were compared and analyzed. The CSA and circumference of the lower extremity, CSA of the lower extremity without fatty acid lining, and muscle CSA in the respective positions of the 31 supplementary volunteers were measured using MR images. The relationship between the muscle CSA and lower limb circumference and CSA was analyzed. The measured circumference and CSA based on 3D scan data were consistent with those based on MR images. A better linear correlation was observed between lower limb CSA and the square of the circumference, between muscle CSA and lower limb CSA without fatty acid lining, and between muscle CSA and calf CSA. This finding indicates that the skeletal muscle CSA of the lower extremity can be estimated reliably based on lower limb circumference measured using 3D scan data. This study verified the feasibility of estimating muscle CSA using structured light 3D scanning technology and provided a simple method for monitoring muscle atrophy in space flights and clinics.

Việc đánh giá độ sâu của vết bỏng là một nhiệm vụ cứu sống tính mạng và rất thách thức, đòi hỏi các kỹ thuật khách quan để hoàn thành. Mặc dù đánh giá bằng mắt là phương pháp thường được các bác sĩ phẫu thuật sử dụng nhất, nhưng độ chính xác và độ tin cậy của nó chỉ dao động từ 60 đến 80%, và mang tính chủ quan, thiếu các hướng dẫn tiêu chuẩn. Hiện tại, cơ sở tiêu chuẩn duy nhất để đánh giá lâm sàng về độ sâu của vết bỏng là Hình ảnh Doppler Laser (LDI), đo lường vi tuần hoàn trong mô da và cung cấp thời gian hồi phục tiềm năng của các vết bỏng tương ứng với độ sâu của chấn thương với độ chính xác đạt tới 100%. Tuy nhiên, việc sử dụng LDI bị hạn chế bởi nhiều yếu tố, bao gồm chi phí cao và chi phí chẩn đoán, độ chính xác của nó bị ảnh hưởng bởi sự di chuyển, điều này làm cho việc đánh giá bệnh nhân thiếu niên trở nên khó khăn, và yêu cầu mức độ chuyên môn cao từ con người để vận hành thiết bị, cũng như chỉ có thể đạt độ chính xác 100% sau 72 giờ. Những thiếu sót này làm nổi bật sự cần thiết của một kỹ thuật khách quan và có khả năng chi trả. Trong nghiên cứu này, chúng tôi tận dụng kỹ thuật học sâu chuyển giao bằng cách sử dụng hai mô hình đã được đào tạo trước là ResNet50 và VGG16 để trích xuất các mẫu hình ảnh (ResFeat50 và VggFeat16) từ một tập dữ liệu bỏng gồm 2080 hình ảnh RGB bao gồm da khỏe mạnh, vết bỏng độ một, độ hai và độ ba được phân phối đồng đều. Sau đó, chúng tôi sử dụng Máy vector hỗ trợ Nhị phân (SVM) cho việc dự đoán đa lớp và đã được đào tạo bằng cách sử dụng 10 lần kiểm tra chéo để đạt được sự cân bằng tối ưu giữa thiên lệch và phương sai. Phương pháp đề xuất cho độ chính xác dự đoán tối đa đạt 95.43% khi sử dụng ResFeat50 và 85.67% khi sử dụng VggFeat16. Độ hồi phục, độ chính xác trung bình và F1-score lần lượt đạt 95.50%, 95.50%, 95.50% cho cả ResFeat50 và VggFeat16 và 85.75%, 86.25%, 85.75% đối với VggFeat16. Quy trình đề xuất đã đạt được độ chính xác dự đoán tiên tiến và điều thú vị là cho thấy quyết định có thể được đưa ra trong vòng chưa đến một phút về việc liệu chấn thương có cần can thiệp phẫu thuật như ghép da hay không.