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ISSN 0928-7329 (P)
ISSN
1878-7401 (E)
Impact Factor 2024: 1.4
Technology and Health Care is intended to serve as a forum for the presentation of original articles and technical notes, observing rigorous scientific standards. Furthermore, upon invitation, reviews, tutorials, discussion papers and minisymposia are featured.
The following types of contributions and areas are considered:
1. Original articles:
Technology development in medicine: New concepts, procedures and devices associated with the use of technology in medical research and clinical practice are presented to a readership with a widespread background in engineering and/or medicine.
Significance of medical technology and informatics for healthcare: The appropriateness, efficacy and usefulness deriving from the application of engineering methods, devices and informatics in medicine and with respect to public health are discussed.
2. Technical notes:
Short communications on novel technical developments with relevance for clinical medicine.
3. Reviews and tutorials (upon invitation only):
Tutorial and educational articles for persons with a primarily medical background on principles of engineering with particular significance for biomedical applications and vice versa are presented.
4. Minisymposia (upon invitation only):
Under the leadership of a Special Editor, controversial issues relating to healthcare are highlighted and discussed by various authors.
Abstract: Recently, advances in computers and high-speed communication tools have led to enhancements in remote medical consultation research. Laws in some localities require hospitals to encrypt patient information (including images of the patient) before transferring the data over a network. Therefore, developing suitable encryption algorithms is quite important for modern medicine. This paper demonstrates a digital image encryption algorithm based on chaotic mapping, which uses the no-period and no-convergence properties of a chaotic sequence to create image chaos and pixel averaging. Then, the chaotic sequence is used to encrypt the image, thereby improving data security. With this method, the security of…data and images can be improved.
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Keywords: Digital image, chaotic sequence, image encryption
Abstract: BACKGROUND: Pneumatic artificial muscles are quite promising actuators for humanoid robots owing to their similar characteristics with human muscles. Moreover, biologically inspired musculoskeletal systems are particularly important for humanoid robots to perform versatile dynamic tasks. OBJECTIVE: This study aims to develop a pneumatic musculoskeletal biped robot, and its controller, to realize human-like walking. METHODS: According to the simplified musculoskeletal structure of human lower limbs, each leg of the biped robot is driven by nine muscles, including three pairs of monoarticular muscles which are arranged in the flexor-extensor form, as well as three biarticular…muscles which span two joints. To lower cost, high-speed on/off solenoid valves rather than proportional valves are used to control the muscles. The joint trajectory tracking controller based on PID control method is designed to achieve the desired motion. Considering the complex characteristics of pneumatic artificial muscles, the control model is obtained through parameter identification experiments. RESULTS: Preliminary experimental results demonstrate that the biped robot is able to walk with this control strategy. CONCLUSION: The proposed musculoskeletal structure and control strategy are effective for the biped robot to achieve human-like walking.
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Keywords: Biped robot, musculoskeletal structure, pneumatic artificial muscles, PID control
Abstract: BACKGROUND: Intravascular ultrasound (IVUS) has been widely used in diagnosis and interventional treatment of cardiac vessel diseases. The coronary artery IVUS images are usually polluted by motion artifacts caused by cardiac motion, pulsatile blood and catheter twist during continuous pullback acquisition. OBJECTIVE: Strategies for rigid and elastic registration of coronary artery IVUS studies are developed to suppress the longitudinal motion and misalignment between successive frames. METHODS: Rigid registration is performed by searching for the optimal matching for each frame in other cycles based on the cyclic variation of gray-scale features. The image sequence…is gated to properly identify the frames in each cardiac phase. Then, elastic registration between frames is achieved through an optimization algorithm based on thin plate spline (TPS) to correct the misalignment of successive slices. RESULTS: Experimental results with in vivo image data shows that the rigid registration performs better than the offline ECG gating. The elastic mapping relation between lumen contours in successive frames is smooth and continuous. CONCLUSION: The serrated vessel wall borders in longitudinal cuts are smoothed after rigid registration while image segmentation and feature extraction are required. The point-to-point correspondence between lumen contours detected from two matched frames is obtained with elastic registration.
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Abstract: BACKGROUND: Postpartum hemorrhage (PPH) is the most common cause of parturient death worldwide [1]. However, most cases of PPH can be avoided. OBJECTIVE: This paper employs statistical methods to screen risk factors of PPH and calculate relevant parameters. METHODS: Multivariable logistic regression analysis was applied to obtain the regression equation and odds ratio (OR) value. The determined risk factors were assigned comprehensive and reasonable scores according to scientific relevance and reasoning according to the OR value. PPPH values were calculated in order to assess the morbidity of PPH. RESULTS:…The scores of pregnant women could be intuitively used to show the risk of getting PPH. CONCLUSIONS: Through the above methods, a comprehensive risk evaluation method of detecting PPH was developed.
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Keywords: Postpartum hemorrhage, high risk factors, comprehensive scores
Abstract: BACKGROUND: Fetal electrocardiography (FECG) places electrodes on the maternal abdomen to convert the fetal electrocardiosignals into fetal heart rate (FHR), improving the accuracy and comfort of pregnant woman. At the same time, FECG simplifies the procedure of long term monitoring in the perinatal period. OBJECTIVE: Investigating the influence of gestational age and time of day on FHR features to distinguish between non-stress test (NST) normal fetuses and NST suspicious fetuses. METHODS: A novel method of FHR baseline estimation was presented; then baseline value and fetal heart rate variation (FHRV) were analyzed in the…time domain using FHR signals recorded from 52 fetuses. RESULTS: Baseline values in 1:00, 2:00, 4:00, 5:00 and heart rate variation (HRV) distribution showed a significant difference (p< 0.05) between NST normal fetuses and NST suspicious fetuses. CONCLUSIONS: The results suggest that NST normal and suspicious fetuses had same outcome and different FHR features. Accurately distinguishing normal fetuses and suspicious fetuses is important for lowering the false positive rate and reducing unnecessary clinical intervention.
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Abstract: BACKGROUND: There are two major classes of cardiac tissue models: the ionic model and the FitzHugh-Nagumo model. During computer simulation, each model entails solving a system of complex ordinary differential equations and a partial differential equation with non-flux boundary conditions. The reproducing kernel method possesses significant applications in solving partial differential equations. The derivative of the reproducing kernel function is a wavelet function, which has local properties and sensitivities to singularity. Therefore, study on the application of reproducing kernel would be advantageous. OBJECTIVE: Applying new mathematical theory to the numerical solution of the ventricular muscle model…so as to improve its precision in comparison with other methods at present. METHODS: A two-dimensional reproducing kernel function inspace is constructed and applied in computing the solution of two-dimensional cardiac tissue model by means of the difference method through time and the reproducing kernel method through space. RESULTS: Compared with other methods, this method holds several advantages such as high accuracy in computing solutions, insensitivity to different time steps and a slow propagation speed of error. It is suitable for disorderly scattered node systems without meshing, and can arbitrarily change the location and density of the solution on different time layers. CONCLUSIONS: The reproducing kernel method has higher solution accuracy and stability in the solutions of the two-dimensional cardiac tissue model.
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Abstract: Urethral ultrasonography is non-invasive and able to indicate the urethral lumen clearly, as well as the surrounding tissues of the posterior urethra, without contrast agent or X-ray irradiation. In this paper, we evaluate the reliability of urethral ultrasonography in the diagnosis of dysuria following bipolar transurethral plasma kinetic prostatectomy (TUPKP). A total of 120 benign prostate hyperplasia (BPH) patients with dysuria undergoing TUPKP were enrolled in this study, with a mean age of 72.8 years. All the patients received urethral ultrasonography, urethroscopy and bladder neck urethra stenosis oulectomy. Among the 120 cases, there were 22 cases of bladder neck closure,…20 bladder orifice stricture, 60 urethral stricture, 10 prostate remnants, 2 calculi in prostatic urethra, 4 dysfunction of bladder detrusor muscle and 2 flap of internal urethral orifice. χ2 -test was used for the comparison of ultrasonography and urethral cystoscopy in the diagnosis of dysuria following TRPKP, and no significant difference was found between two diagnostic tools (χ 2 = 0.94, P > 0.05). Urethral ultrasonography is a reliable and minimally invasive diagnostic tool for dysuria following TUPKP and is conducive to early treatment of dysuria following prostatectomy.
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Abstract: BACKGROUND: Vascularized bone grafting was used in the treatment of osteonecrosis femoral head, which may directly influence the pathologic event of femoral head. OBJECTIVE: This paper evaluates hemodynamic changes in osteonecrosis treatment of the femoral head (ONFH) with iliac bone flaps from the lateral femoral circumflex artery ascending branches via digital subtraction angiography. METHODS: A total of 48 patients, (31 males and 17 females; 38 at stage II and 10 at stage III), were treated with iliac bone flaps pedicled with the ascending branch of the lateral femoral circumflex artery. DSA…was performed on all 48 patients preoperatively and 6 months postoperatively, and 10 years postoperatively on 1 patient. RESULTS: Six months after surgery, femoral head blood supplies were distinctly visualized in the selective DSA in 44 cases. 4 patients showed poor or failed vessel pedicle filling in the transplanted bone flaps. Total hip arthroplasty was performed on these 4 patients. DSA was conducted 10 years post-operation in 1 case; the subject showed normal blood supply of the femoral head. CONCLUSIONS: The anatomical position of the ascending branch of the lateral femoral circumflex artery was constant. Digital subtraction angiography successfully examined hemodynamic changes in osteonecrosis treatment of the femoral head with vascularized bone flaps.
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Keywords: Femoral head necrosis, digital subtraction angiography, bone remodelling
Abstract: BACKGROUND: Gestational diabetes mellitus (GDM) is not easily detected. The difficulty in detecting GDM is largely due to the late onset of clinical symptoms as well as the various complications that result from GDM [1]. OBJECTIVE: GDM greatly influences both mother and child. Therefore, the purpose of this study was to reduce the morbidity of GDM. METHODS: In this study, risk factors that influence GDM were selected through statistical analysis. Multivariable logistic regression analysis was used to obtain the regression equation and Odds Ratio (OR) value. The risk score of…each factor was obtained according to the OR value. RESULTS: The score of every pregnant woman could be very intuitively used to show the risk of getting GDM. CONCLUSION: Through the above methods, a comprehensive risk evaluation method of detecting GDM was developed.
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Abstract: BACKGROUND: Esophageal reconstruction is the key issue in esophageal surgery. However, currently there is no satisfied technique to repair esophagus after surgery. OBJECTIVE: To combine an inner chitosan stent and a muscle tissue with vascular pedicle to repair the esophageal defect in cervical segment. METHODS: Esophageal defect was repaired using the combination of a muscle tissue flap and a chitosan tube stent in experimental group while only muscle tissue flap was utilized in controls for comparison. One animal in each group was sacrificed at week 3, 6 and 9 after operation…respectively to exam the healing status. Barium X-ray was used to evaluate the esophageal status in 12 weeks. RESULTS: Histology showed the inflammatory response in 3 weeks after surgery, the chitosan stent was partially absorbed in 6 weeks, and there was no obvious fibrotic proliferation in experimental group; while the fibrotic proliferation and esophageal stenosis were obvious in controls, the chitosan stent was completely absorbed in 9 weeks, and squamous epidermis cells were observed. Twelve weeks later, the barium swallow went smoothly through the esophagus with noticeable peristalsis in the experimental group; esophageal stenosis without peristalsis was observed in controls. CONCLUSION: The combination of chitosan stent and muscle tissue flap is feasible to reconstruct a partial defect in esophagus.
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Abstract: OBJECTIVE: To relieve large airway obstruction in a patient with advanced non-small cell lung cancer (NSCLC) by injecting the mouse-human chimeric monoclonal antibody radiolabeled with iodine 131 chimeric tumor necrotic treatment (131 I-chTNT) and to study the irradiation absorption in the tumor and critical organs. METHODS: A 50-year-old patient with NSCLC was treated with radioimmunotherapy. His airway was still obstructed in spite of intensive chemotherapy and radiotherapy.131 I-chTNT was injected into the tumor at the right bronchus through a fiberscope. A131 I scan was performed during treatment, and a computed tomography (CT) scan of the chest…and fiberscope were performed pre- and post-treatment.131 I-chTNT distribution in tissues was followed for up to 4 weeks using gamma camera imaging. RESULTS: The radiation material accumulated notably in the tumor, relieving the patient's symptoms by suppressing the tumor. Recanalization of the airway was achieved so that the patient was able to breathe easily and cough. CONCLUSION: As a new type of radioimmunotherapy,131 I-chTNT may be helpful in treatment of advanced lung cancer.
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Abstract: Revised high-heeled shoes (HHSs) were designed to improve the shortcomings of standard HHSs. This study was conducted to compare revised and standard HHSs with regard to joint angles and electromyographic (EMG) activity of the lower extremities during standing. The participants were five healthy young women. Data regarding joint angles and EMG activity of the lower extremities were obtained under three conditions: barefoot, when wearing revised HHSs, and when wearing standard HHSs. Lower extremity joint angles in the three dimensional plane were confirmed using a VICON motion capture system. EMG activity of the lower extremities was measured using active bipolar surface…EMG. Kruskal-Wallis one-way analysis of variance by rank applied to analyze differences during three standing conditions. Compared with the barefoot condition, the standard HHSs condition was more different than the revised HHSs condition with regard to lower extremity joint angles during standing. EMG activity of the lower extremities was different for the revised HHSs condition, but the differences among the three conditions were not significant. Wearing revised HHSs may positively impact joint angles and EMG activity of the lower extremities by improving body alignment while standing.
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Abstract: Telehealth cost analysis has become a crucial issue for governments in recent years. In this study, we examined cases of metabolic syndrome in Hualien County, Taiwan. This research adopted the framework proposed by Marchand to establish a study process. In addition, descriptive statistics, a t test, analysis of variance, and regression analysis were employed to analyze 100 questionnaires. The results of the t$ test revealed significant differences in medical health expenditure, number of clinical visits for medical treatment, average amount of time spent commuting to clinics, amount of time spent undergoing medical treatment, and average number of people accompanying patients…to medical care facilities or assisting with other tasks in the past one month, indicating that offering telehealth care services can reduce health expenditure. The statistical analysis results revealed that customer satisfaction has a positive effect on reducing health expenditure. Therefore, this study proves that telehealth care systems can effectively reduce health expenditure and directly improve customer satisfaction with medical treatment.
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Abstract: BACKGROUND: The potential mechanism of compression apparel remains unclear to date because of insufficient knowledge on the influence of compressive level on muscular responses. OBJECTIVE: To explore the influence of external leg compression on (a) the muscle force and endurance of the quadriceps femoris and (b) the muscle activation patterns during prolonged muscle actions. METHODS: Twelve male participants performed consecutive maximal concentric muscle actions of the quadriceps in compression garment (CG) and control condition (CON) at two angular velocities on the Contrex. The EMG amplitude and frequency of the rectus femoris (RF), vastus…lateralis (VL), and vastus medialis were quantified during the concentric phase of the knee extension movement. RESULTS: There was no significant compression effect on muscle force and total work during knee extensions. Contrarily, the overall EMG amplitude was significantly lower in CG than in CON at 60 and 300°/s. Additionally, the EMG frequency of the RF and VL was significantly higher in CG than in CON at 60°/s. CONCLUSION: Increased external pressure is associated with changes in EMG time and frequency domain behavior. These effects can potentially relieve muscle fatigue and improve muscle endurance during long-term exercise.
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Keywords: External leg compression, muscle contraction, EMG amplitude, EMG frequency
Abstract: BACKGROUND: The goal of a brain-computer interface (BCI) is to enable communication by pure brain activity without neural and muscle control. However, the practical use of BCIs is limited by low information transfer rate. Recently, code modulation visual evoked potential (c-VEP) based BCIs have exhibited great potential in establishing high-rate communication between the brain and the external world. OBJECTIVE: This study aims at exploring a more effective modulation code than the commonly used pseudorandom M sequence for c-VEP based BCIs (c-VEP BCIs) in order to increase the detection accuracy of stimulus targets and the resulting information…transfer rate. METHOD: Golay complementary sequence pair is used for constructing the modulation code of c-VEP BCIs due to their superior autocorrelation property. The modulation code is created by concatenating a pair of Golay complementary sequences. Sixteen target stimuli are modulated by the Golay code and its time shift versions. RESULTS: Through offline analysis on data recorded from seven subjects and online test on five subjects, the Golay code modulated BCI yielded higher detection accuracy and information transfer rate than those achieved by M sequence. CONCLUSION: The Golay code modulated BCI demonstrates a high performance compared with the M sequence modulated systems, and it is applicable to persons with motor disabilities.
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Abstract: In this paper, a method for classifying electroencephalographic (EEG) recordings with images as stimulation is introduced, which aims at selecting the target images. EEG recordings to be processed are referred to the onset of the test images with a single stimulation so as to avoid spending extra time on repeating images. Independent component analysis (ICA) is used to reduce the redundancy of EEG recordings, and wavelet packet (WP) analysis is efficient for dealing with the non-stationary character of brain activity. Feature vectors are extracted by a method that combines these two algorithms. The support vector machine is used as a…classifier, carrying out the classification result. The experimental results demonstrate that the accuracy of this method's image classification is affected very little by different classifier parameters. The best result achieves 90% accuracy, which indicts it is feasible for classifying images with a single stimulation.
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Keywords: EEG, independent component analysis, wavelet-packet, support vector machine
Abstract: Ultrasound diagnosis is a widely used medical tool. Among the various ultrasound techniques, ultrasonic imaging is particularly relevant. This paper presents an improvement to a two-dimensional (2D) ultrasonic system using measurements taken from perpendicular planes, where digital signal processing techniques are used to combine one-dimensional (1D) A-scans were acquired by individual transducers in arrays located in perpendicular planes. An algorithm used to combine measurements is improved based on the wavelet transform, which includes a denoising step during the 2D representation generation process. The inclusion of this new denoising stage generates higher quality 2D representations with a reduced level of speckling.…The paper includes different 2D representations obtained from noisy A-scans and compares the improvements obtained by including the denoising stage.
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Abstract: An abdominal aortic aneurysm doesn't result in specific symptoms, and so providing a successful diagnosis can be challenging. Patients may require surgery for successful treatment, with the risk of aortic rupture being dependent on diameter. In this study, a CT screen of a patient with an aneurysm of the abdominal aorta was processed. In order to provide a more accurate and comfortable diagnosis, and to more easily determine the diameter of the abdominal aortic aneurysm, the Sobel and Top-hat methods were employed. Using a filtered screen overlap for the CT scan, the aortic diameter of a patient could be compared…with the diameter of a healthy individual, thus allowing an immediate and accurate comparison. It was found that with a diameter of more than 40 mm the risk of rupture is higher.
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Abstract: BACKGROUND: Propagation of photon signals in biological systems, such as neurons, accompanies the production of biophotons. The role of biophotons in a cell deserves special attention because it can be applied to diverse optical systems. OBJECTIVE: This work has been aimed to investigate the time behavior of biophoton signals emitted from living systems in detail, by introducing a Hamiltonian that describes the process. The ratio of the energy loss during signal dissipation will also be investigated. METHOD: To see the adiabatic properties of the biophoton signal, we introduced an adiabatic invariant of…the system according to the method of its basic formulation. RESULTS: The energy of the released biophoton dissipates over time in a somewhat intricate way when t is small. However, after a sufficient long time, it dissipates in proportion (1+λ_0t)^2 to where λ_0 is a constant that is relevant to the degree of dissipation. We have confirmed that the energy of the biophoton signal oscillates in a particular way while it dissipates. CONCLUSION: This research clarifies the characteristics of radiation fields associated with biophotons on the basis of Hamiltonian dynamics which describes phenomenological aspects of biophotons signals.
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Keywords: Biophoton, energy dissipation, hamiltonian, damped harmonic oscillator, biological system
Abstract: The aim of this study is to observe the differences between mechanical and electrical dyssynchrony in patients with impaired systolic ventricular function and symptomatic heart failure and to highlight the importance of mechanical dyssynchrony besides electrical dyssynchrony in clinical guidelines and clinical practice. Fifty-eight patients with heart failure, who are with the New York Heart Association (NYHA) functional class II-IV and left ventricular ejection fraction (LVEF) under 35%, were enrolled. Patients were divided into two groups, according to the duration of QRS complex (> 120 ms and ≤ 120 ms respectively). Echocardiographic parameters of interventricular (interventricular mechanical delay - IMD)…and intraventricular (septal-to-posterior wall motion delay - SPWMD) dyssynchrony were measured in both groups. Results indicate that the duration of the QRS complex (i.e. electrical dyssynchrony) is not a fully reliable indicator of ventricular dyssynchrony; therefore ecocardiographic evaluation of mechanical dyssynchrony should also be recommended for better selection of candidates for cardiac resynchronization therapy (CRT).
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Abstract: Diffusion tensor magnetic resonance (DTMR) imaging and diffusion tensor imaging (DTI) have been widely used to probe noninvasively biological tissue structures. However, DTI suffers from long acquisition times, which limit its practical and clinical applications. This paper proposes a new Compressed Sensing (CS) reconstruction method that employs joint sparsity and rank deficiency to reconstruct cardiac DTMR images from undersampled k-space data. Diffusion-weighted images acquired in different diffusion directions were firstly stacked as columns to form the matrix. The matrix was row sparse in the transform domain and had a low rank. These two properties were then incorporated into the CS…reconstruction framework. The underlying constrained optimization problem was finally solved by the first-order fast method. Experiments were carried out on both simulation and real human cardiac DTMR images. The results demonstrated that the proposed approach had lower reconstruction errors for DTI indices, including fractional anisotropy (FA) and mean diffusivities (MD), compared to the existing CS-DTMR image reconstruction techniques.
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Abstract: Finding the minimum number of appropriate biomarkers for specific targets such as a lung cancer has been a challenging issue in bioinformatics. We propose a hierarchical two-phase framework for selecting appropriate biomarkers that extracts candidate biomarkers from the cancer microarray datasets and then selects the minimum number of appropriate biomarkers from the extracted candidate biomarkers datasets with a specific neuro-fuzzy algorithm, which is called a neural network with weighted fuzzy membership function (NEWFM). In this context, as the first phase, the proposed framework is to extract candidate biomarkers by using a Bhattacharyya distance method that measures the similarity of two…discrete probability distributions. Finally, the proposed framework is able to reduce the cost of finding biomarkers by not receiving medical supplements and improve the accuracy of the biomarkers in specific cancer target datasets.
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Abstract: BACKGROUND: For implementing autonomous rehabilitation exercises for upper limb hemiplegic patients, interfaces and a rehabilitation scenario that allow lateral and bilateral motions in a rehabilitation exercise robot are proposed. OBJECTIVE: The proposed method measures the motion information generated from the unaffected part and projects it to an affected part in which the affected part expresses motions of the unaffected part. METHODS: Both the accelerometer and gyro data were merged for estimating the motion information of the unaffected part. Also, HDR and complementary filters were applied to improve measurement errors in a data merging…process. RESULTS: For verifying the proposed method, a device, which is similar to a human body joint, was fabricated. Then, the angular values estimated by using an inertial sensor and the encoder values from the device were compared. In addition, a camera analysis was used to verify the proposed rehabilitation scenario by applying the rehabilitation interface proposed in this study to an exo-skeleton robot arm. CONCLUSION: It is possible to apply the method proposed in this study to the control variables in different upper limb rehabilitation exercise robots. Thus, it is expected that patient centered active lateral/bilateral rehabilitation exercises can be performed through this interface method.
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Keywords: Lateral and bilateral upper limb movement, upper limb rehabilitation, active rehabilitation, rehabilitation interface
Abstract: This paper presents a method to characterize tissue thermal damage by taking into account the thermal-mechanical effect of soft tissues for thermal ablation. This method integrates the bio-heating conduction and non-rigid motion dynamics to describe thermal-mechanical behaviors of soft tissues and further extends the traditional tissue damage model to characterize thermal-mechanical damage of soft tissues. Simulations and comparison analysis demonstrate that the proposed method can effectively predict tissue thermal damage and it also provides reliable guidelines for control of the thermal ablation procedure.
Abstract: BACKGROUND: Kidney function assessment from renography has great potential for clinical diagnosis. Compartment models are the main analytical models in this field and the vascular compartment is the most important one, whether in the two-compartment model or three-compartment model. Currently, there are some published research studies on renal cortex segmentation. However, there are few publications introducing the methods on how to segment the vascular compartment yet. OBJECTIVE: The objective of this paper is to segment the vascular compartment automatically. METHODS: This method was tested on multi-phase scan images. A feature image reconstructed from…the original images was used to segment the vascular compartment. It used the features of the time-density curve of each voxel in the contrast-enhanced images to distinguish vascular space from other areas. RESULTS: The segmentation result was evaluated by the renal glomerular filtration rate (GFR) analysis of a two-compartment model with the Patlak-Rutland technique. The dataset contained 11 kidney subjects whose GFR ranged from 19.8 ml/min to 74.9 ml/min. The results showed that the correlation between reference GFR and model derived GFR was 0.919 (P< 0.001). CONCLUSION: Compared with segmentation performed on certain phase images, this method can avoid the problem of subjective phase selection. For a given kidney data, the proposed method can always obtain the same segmentation result automatically.
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Keywords: Renal function, GFR, renography, vascular compartment segmentation, time density curve, contrast-enhanced image
Abstract: It is important to detect abnormal brains accurately and early. The wavelet-energy (WE) was a successful feature descriptor that achieved excellent performance in various applications; hence, we proposed a WE based new approach for automated abnormal detection, and reported its preliminary results in this study. The kernel support vector machine (KSVM) was used as the classifier, and quantum-behaved particle swarm optimization (QPSO) was introduced to optimize the weights of the SVM. The results based on a 5 × 5-fold cross validation showed the performance of the proposed WE + QPSO-KSVM was superior to ``DWT + PCA + BP-NN'', ``DWT +…PCA + RBF-NN'', ``DWT + PCA + PSO-KSVM'', ``WE + BPNN'', ``WE +$ KSVM'', and ``DWT $+$ PCA $+$ GA-KSVM'' w.r.t. sensitivity, specificity, and accuracy. The work provides a novel means to detect abnormal brains with excellent performance.
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Keywords: Magnetic resonance imaging, particle swarm optimization, quantum-behaved PSO, wavelet energy
Abstract: BACKGROUND: In this study, the authors cultivated ECV-304 in vitro and incubated cells with H2 O2 , established injury models, and induced oxidized endothelial cell apoptosis. This model makes it possible to choose suitable concentrations of North Schisandra Lignans. OBJECTIVE: To study the protective effects of North Schisandra Lignans on human umbilical vein endothelial cell injuries. METHODS: Endothelial cell growth and proliferation activity were detected through the MTT method. The colorimetric method was used to determine superoxide dismutase (SOD) activity in the cell culture solution, as well as malondialdehyde (MDA) content…in the cell. RESULTS: North Schisandra Lignans noticeably decreased ECV-304 cell injury induced by H2 O2 . Moderate and high concentrations of North Schisandra Lignans could significantly lower MDA content and heighten SOD activity. These differences were significant compared to the H2 O2 group (P< 0.05). CONCLUSIONS: North Schisandra Lignans had an obvious protective effect on ECV-304 injured by H2 O2 $. The mechanism decreases MDA production and heightened SOD activity.
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Keywords: North Schisandra Lignans, vascular endothelial cell, superoxide dismutase, malondialdehyde
Abstract: BACKGROUND: As it is not easy to investigate various variables that affect exercise efficacies and cause injuries while pedaling in the actual experiment, especially for the elderly, the musculoskeletal model simulation with a comparison of measured electromyography (EMG) data could be used to minimize experimental trials. OBJECTIVE: The measured EMG data were compared with the muscle activities from the musculoskeletal model through forward (FD) and inverse dynamic (ID) analysis. METHODS: EMG was measured from eight young adult (20's) and eight elderly (70's) in three minutes pedaling with a constant load and…40 revolutions per minute (RPM) cadence. The muscles used for the analysis were the VastusLateralis, Tibialis Anterior, Bicep Femoris, and Gastrocnemius Medial. Pearson's correlation coefficients of the muscle activity patterns, on-off set, and peak timing at the maximum muscle activity were calculated and compared. BIKE3D and GaitLowerExtremity model were used for the FD and ID simulation. RESULTS: There are significant correlations in the muscle activity patterns except in the case of Biceps Femoris muscle by ID. Thus, it can be concluded that muscle activities of model & EMG showed similar results. CONCLUSION: The result shows that it could be possible to use the musculoskeletal model for various pedaling simulations.
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Abstract: BACKGROUND: With the rapid development of modern medical imaging technology, medical image classification has become more important for medical diagnosis and treatment. OBJECTIVE: To solve the existence of polysemous words and synonyms problem, this study combines the word bag model with PLSA (Probabilistic Latent Semantic Analysis) and proposes the PLSA-BOW (Probabilistic Latent Semantic Analysis-Bag of Words) model. METHODS: In this paper we introduce the bag of words model in text field to image field, and build the model of visual bag of words model. RESULTS: The method enables the word…bag model-based classification method to be further improved in accuracy. CONCLUSIONS: The experimental results show that the PLSA-BOW model for medical image classification can lead to a more accurate classification.
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Keywords: Medical image classification, bag of words model, PLSA
Abstract: In this paper, an Archimedean planar spiral antenna for the application of thermotherapy was designed. This type of antenna was chosen for its compact structure, flexible application and wide heating area. The temperature field generated by the use of this Two-armed Spiral Antenna in a muscle-equivalent phantom was simulated and subsequently validated by experimentation. First, the specific absorption rate (SAR) of the field was calculated using the Finite Element Method (FEM) by Ansoft's High Frequency Structure Simulation (HFSS). Then, the temperature elevation in the phantom was simulated by an explicit finite difference approximation of the bioheat equation (BHE). The temperature…distribution was then validated by a phantom heating experiment. The results showed that this antenna had a good heating ability and a wide heating area. A comparison between the calculation and the measurement showed a fair agreement in the temperature elevation. The validated model could be applied for the analysis of electromagnetic-temperature distribution in phantoms during the process of antenna design or thermotherapy experimentation.
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Abstract: BACKGROUND: As two of the new biological electrical impedance tomography (EIT), magneto-acoustic tomography (MAT) and magneto-acousto-electrical tomography (MAET) achieve both the high contrast property of EIT and the high spatial resolution property of sonography through combining EIT and sonography. As both MAT and MAET contain a uniform magnetic field, vibration and electrical current density, there is a secondary process both in MAT and in MAET, which is MAET and MAT respectively. OBJECTIVE: To analyze the effect of the secondary process on mass point vibration velocity (MPVV) propagation in MAT and MAET. METHODS: By…analyzing the total force to the sample, the wave equations of MPVV in MAT and MAET - when the secondary processes were considered - were derived. The expression of the attenuation constant in the wave number was derived in the case that the mass point vibration velocity propagates in the form of cylindrical wave and plane wave. Attenuations of propagation of the MPVV in several samples were quantified. RESULTS: Attenuations of the MPVV after propagating for 1 mm in copper or aluminum foil, and for 5 cm in gel phantom or biological soft tissue were less than 1%. CONCLUSION: Attenuations of the MPVV in MAT and MAET due to the secondary processes are relatively minor, and effects of the secondary processes on MPVV propagation in MAT and MAET can be ignored.
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Keywords: Magneto-acoustic tomography, magneto-acousto-electrical tomography, wave equation of mass point vibration velocity, linear damping
Abstract: OBJECTIVE: To study the safety and effectiveness of the Heart-Gallbladder acupuncture treatment for motor aphasia after stroke via clinical studies. METHODS: Sixty valid patients were divided into two groups randomly with a ratio of 1:1. The treatment group was the Heart-Gallbladder acupuncture group and the control group was the conventional acupuncture group. The two groups underwent testing before and after treatments, which included: the Aphasia Battery of Chinese (ABC), the Chinese functional communication profile (CFCP), and the Boston diagnostic aphasia examination (BDAE). RESULTS: All the BDAE, CFCP and ABC results showed…a significant difference between the two groups after treatment (P< 0.05), indicating that the Heart-Gallbladder acupuncture treatment for motor aphasia after stroke can reduce the degree of aphasia and improve patients' daily communication skills more than the conventional acupuncture treatment. The Heart-Gallbladder acupuncture treatment is better than the conventional acupuncture treatments for motor aphasia after stroke, with significantly improved scores for fluency, repetition, naming, and reading. CONCLUSIONS: Both the Heart-Gallbladder acupuncture and the conventional acupuncture are effective in the treatment of motor aphasia after stroke. Nevertheless, when compared to the conventional acupuncture, the Heart-Gallbladder acupuncture had better efficacy and it is safe as well.
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Keywords: Motor aphasia, stroke, Heart-Gallbladder treatment, tongue acupuncture
Abstract: BACKGROUND: Lasers are advantageous in some applications to stimulate a small target area and is used in various fields such as optogenetic, photoimmunological and neurophysiological studies. OBJECTIVE: This study aims to implement a non-contact sense of touch without damaging biological tissues using laser. METHODS: Various laser parameters were utilized in safety range to induce a sense of touch and investigate the human responses. With heat distribution simulation, the amount of changes in the temperature and the tendency in laser parameters of sensory stimulation were analyzed. RESULTS: The…results showed the identified tactile responses in safety range with various laser parameters and temperature distribution for the laser stimulus was obtained through the simulation. CONCLUSIONS: This study can be applied to the areas of sensory receptor stimulation, neurophysiology and clinical medicine.
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Keywords: Laser stimuli, pulse laser, perception, skin temperature simulation
Abstract: BACKGROUND: Nowadays, stroke is a leading cause of disability in adults. Assessment of motor performance has played an important role in rehabilitation for post stroke patients. Therefore, it is quite important to develop an automatic assessment system of motor function. OBJECTIVE: The purpose of this study is to assess the performance of the single task upper-limb movements quantitatively among stroke survivors. METHODS: Eleven normal subjects and thirty-five subjects with stroke were involved in this study. The subjects, who were wearing the micro-sensor motion capture system, performed shoulder flexion in a sitting…position. The system recorded three-dimensional kinematics data of limb movements in quaternions. By extracting the significant features from these data, we built a linear model to acquire the functional assessment score (FAS). RESULTS: All of the kinematics features have a significant statistical difference (P < 0.05) between patients and healthy people, while the feature values have a high correlation with Fugl-Meyer (FM) scores (r > 0.5, p < 0.05), indicating that these features are able to reflect the level of motion impairment. Furthermore, most samples of the linear model locate in the confidence interval after regression, with the residual approaching a normal distribution. These results show that the FAS is capable of motor function assessment for stroke survivors. CONCLUSION: These findings represent an important step towards a system that can be utilized for precise single task motor evaluation after stroke, applicable to clinical research and as a tool for rehabilitation.
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Keywords: Stroke, rehabilitation, motor assessment, upper-limb, micro-sensor
Abstract: The purpose of this study is to design and fabricate an anthropopathic abdominal phantom for accuracy evaluation of deformable image registration (DIR) algorithms in adaptive radiation therapy. The constructed deformable organs, including the liver, kidney, spleen and stomach, are made of mixture of polyvinyl chloride (PVC) and softener dioctyl terephthalate, while the rigid structures, i.e. vertebrae, are made of white cement. Relation between the PVC-softener blending ratio and organ CT number is studied, and three-dimensional printing technic is employed to create highly anthropopathic organs in terms of organ shape and density. Detailed steps for phantom construction, landmark point placement…and choice of phantom ingredients and construction recipe are introduced. Preliminary results of the mechanical properties of the fabricated organs are also presented. The experimental results indicate that the constructed phantom has satisfactory elastic characteristics and close CT number with corporal organs, and can potentially be applied to simulate real abdominal organ deformation in geometric accuracy validation of DIR algorithms.
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Keywords: Three-dimensional deformable phantom, deformable image registration, PVC, phantom construction
Abstract: BACKGROUND: Doctors who practice Traditional Chinese Medicine (TCM) diagnose using four methods - inspection, auscultation and olfaction, interrogation, and pulse feeling/palpation. The shape and shape changes of the moon marks on the nails are an important indication when judging the patient's health. There are a series of classical and experimental theories about moon marks in TCM, which does not have support from statistical data. OBJECTIVE: To verify some experiential theories on moon mark in TCM by automatic data-processing equipment. METHODS: This paper proposes the equipment that utilizes image processing technology to…collect moon mark data of different target groups conveniently and quickly, building a database that combines this information with that gathered from the health and mental status questionnaire in each test. RESULTS: This equipment has a simple design, a low cost, and an optimized algorithm. The practice has been proven to quickly complete automatic acquisition and preservation of key data about moon marks. CONCLUSION: In the future, some conclusions will likely be obtained from these data; some changes of moon marks related to a special pathological change will be established with statistical methods.
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Keywords: Moon mark, Traditional Chinese Medicine, real time tracking
Abstract: Magneto-Acousto-Electrical Tomography (MAET) is a novel hybrid modality that can provide a high spatial resolution in determining the electrical conductivity of biological tissue. The present paper primarily analyzes the existing basic formulations with the MAET, derives the propagation equations of the sound wave when the mass density of the biological tissues are variable, and then solves the respective current density and potential difference in an inhomogeneous and homogeneous density medium based on the sound speeds obtained. Finally, numerical simulations are performed. As is shown, sound waves affect magneto-acousto-electrical tomography while varying the biological tissue mass density.
Abstract: BACKGROUND: Efficient mid-range wireless power transfer between transmitter and the receiver has been achieved based on the magnetic resonant coupling method. The influence of electromagnetic field on the human body due to resonant wireless power transfer system (RWPT) should be taken into account during the design process of the system. OBJECTIVE: To analyze the transfer performance of the RWPT system and the change rules of the specific absorption rate (SAR) in the human head model due to the RWPT system. METHODS: The circuit-field coupling method for a RWPT system with consideration of the…displacement current was presented. The relationship between the spiral coil parameters and transfer performance was studied. The SAR in the human head model was calculated under two different exposure conditions. RESULTS: A system with output power higher than 10 W at 0.2 m distance operating at a frequency of approximately 1 MHz was designed. The FEM simulation results show the peak SAR value is below the safety limit which appeared when the human head model is in front of the transmitter. CONCLUSION: The simulation results agreed well with the experimental results, which verified the validity of the analysis and design.
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Keywords: Wireless power transfer, SAR, resonant coupling, field-circuit coupling method, FEM
Abstract: Deformable image registration (DIR) is a critical technic in adaptive radiotherapy (ART) to propagate contours between planning computerized tomography (CT) images and treatment CT/Cone-beam CT (CBCT) image to account for organ deformation for treatment re-planning. To validate the ability and accuracy of DIR algorithms in organ at risk (OAR) contours mapping, seven intensity-based DIR strategies are tested on the planning CT and weekly CBCT images from six Head & Neck cancer patients who underwent a 6 ∼ 7 weeks intensity-modulated radiation therapy (IMRT). Three similarity metrics, i.e. the Dice similarity coefficient (DSC), the percentage error (PE) and the Hausdorff distance…(HD), are employed to measure the agreement between the propagated contours and the physician delineated ground truths. It is found that the performance of all the evaluated DIR algorithms declines as the treatment proceeds. No statistically significant performance difference is observed between different DIR algorithms (p> 0.05), except for the double force demons (DFD) which yields the worst result in terms of DSC and PE. For the metric HD, all the DIR algorithms behaved unsatisfactorily with no statistically significant performance difference (p= 0.273). These findings suggested that special care should be taken when utilizing the intensity-based DIR algorithms involved in this study to deform OAR contours between CT and CBCT, especially for those organs with low contrast.
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Keywords: Adaptive radiotherapy, deformable image registration, CBCT, contour propagation, head & neck cancer
Abstract: Based on compressive sensing (CS) technology, a high resolution confocal microwave imaging algorithm is proposed for breast cancer detection. With the exploitation of the spatial sparsity of the target space, the proposed image reconstruction problem is cast within the framework of CS and solved by the sparse constraint optimization. The effectiveness and validity of the proposed CS imaging method is verified by the full wave synthetic data from numerical breast phantom using finite-difference time-domain (FDTD) method. The imaging results have shown that the proposed imaging scheme can improve the imaging quality while significantly reducing the amount of data measurements and…collection time when compared to the traditional delay-and-sum imaging algorithm.
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Keywords: Microwave imaging, breast cancer detection, compressive sensing (CS), FDTD method
Abstract: BACKGROUND: Existing methods may fail to locate and segment the optic disc (OD) due to imprecise boundaries, inconsistent image contrast and deceptive edge features in retinal images. OBJECTIVE: To locate the OD and detect the OD boundary accurately. METHODS: The method exploits a multi-stage strategy in the detection procedure. Firstly, OD location candidate regions are identified based on high-intensity feature and vessels convergence property. Secondly, a line operator filter for circular brightness feature detection is designed to locate the OD accurately on candidates. Thirdly, an initialized contour is obtained by iterative thresholding and…ellipse fitting based on the detected OD position. Finally, a region-based active contour model in a variational level set formulation and ellipse fitting are employed to estimate the OD boundary. RESULTS: The proposed methodology achieves an accuracy of 98.67% for OD identification and a mean distance to the closest point of 2 pixels in detecting the OD boundary. CONCLUSION: The results illuminate that the proposed method is effective in the fast, automatic, and accurate localization and boundary detection of the OD. The present work contributes to the more effective evaluation of the OD and realizing automatic screening system for early eye diseases to a large extent.
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Abstract: Currently, cardiovascular disease affects a relatively high proportion of the world's population. Thus, developing simple and effective methods for monitoring patients with cardiovascular disease is critical for research. Monitoring the heart rate of patients is a relatively simple and effective method for managing patients with this condition. For patients, the desired heart rate monitoring equipment should be portable, instantaneous, and accurate. Because smartphones have become the most prevalent mobile device, we utilized this technology as a platform for developing a novel heart-rate measurement system. Catering to the phenomenon of people using the front camera of their smartphones as a mirror,…the proposed system was designed to analyze facial-image sequences captured using the front camera. A spatiotemporal alpha-trimmed mean filter was developed to estimate a user's heart rate quickly and accurately. The experimental results show that in addition to achieving these objectives, the developed system outperforms a similar personal computer-based system. In addition, the system performs effectively even when users are wearing glasses. Hence, the proposed system demonstrates practical value for people who must monitor their heart rate daily.
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Abstract: BACKGROUND: In recent years, MR images have been increasingly used in therapeutic applications such as image-guided radiotherapy (IGRT). However, images with low contrast values and noises present challenges for image segmentation. OBJECTIVE: The objective of this study is to develop a robust method based on fuzzy C-means (FCM) method which can segment MR images polluted with Gaussian noise. METHODS: A modified FCM algorithm accommodating non-local pixel information via Hausdorff distance was developed for segmenting MR images. The membership and objective functions were modified accordingly. Segmentations with different weights of the Hausdorff distance…were compared. RESULTS: Segmentation tests using synthetic and MR images showed that the proposed algorithm was better at resolving boundaries and more robust to Gaussian noise. By segmenting a sample MR image of a tumor, we further showed the capability of the method in capturing the centroid of the target region. CONCLUSIONS: The modified FCM algorithm with neighboring information can be used to segment blurry images with potential applications in segmenting motion MR images in image-guided radiotherapy (IGRT).
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Abstract: BACKGROUND: The effective connectivity refers explicitly to the influence that one neural system exerts over another in frequency domain. To investigate the propagation of neuronal activity in certain frequency can help us reveal the mechanisms of information processing by brain. OBJECTIVE: This study investigates the detection of effective connectivity and analyzes the complex brain network connection mode associated with motor imagery (MI) tasks. METHODS: The effective connectivity among the primary motor area is firstly explored using partial directed coherence (PDC) combined with multivariate empirical mode decomposition (MEMD) based on electroencephalography (EEG)…data. Then a new approach is proposed to analyze the connection mode of the complex brain network via the information flow pattern. RESULTS: Our results demonstrate that significant effective connectivity exists in the bilateral hemisphere during the tasks, regardless of the left-/right-hand MI tasks. Furthermore, the out-in rate results of the information flow reveal the existence of the contralateral lateralization. The classification performance of left-/right-hand MI tasks can be improved by careful selection of intrinsic mode functions (IMFs). CONCLUSION: The proposed method can provide efficient features for the detection of MI tasks and has great potential to be applied in brain computer interface (BCI).
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Keywords: Electroencephalogram (EEG), information flow pattern, multivariate empirical mode decomposition (MEMD), effective connectivity, motor imagery (MI)
Abstract: BACKGROUND: Impedance cardiography (ICG) is an inexpensive, noninvasive technique for estimating hemodynamic parameters. ICG can be used to obtain the ejection fraction of the left atrium and to monitor systolic time intervals. Traditional ICG technique does not enable unambiguous detection of the left ventricle ejection time (LVET) and the time relationships between specific marker points. OBJECTIVE: This work aims to approbate a new approach for ICG signal processing using wavelet transform (WT) and to investigate the possibilities of this approach for determination of the parameters which are related to the stroke volume (SV), in particular…LVET. METHODS: Thoracic tetrapolar polyrheocardiography method for simultaneous registration of ECG, ICG and phonocardiograms has been used. A control group consisted of eight healthy men aged 20-25 years. In addition, four patients with essential hypertension participated in the study. Wavelet representation of the ICG data produced local maxima in a two dimensional distribution of the wavelet coefficient. Each extremum point was characterized by the amplitude, scale and time, which determine SV. RESULTS: LVET was defined as the scale corresponding to the E-wave maximum related to the systolic phase of the cardiac cycle. Also, we defined the initial systolic time interval (ISTI) as the time interval between R peak in the ECG and E-wave maximum on the wavelet plane. During functional test LVET and ISTI values defined by WT demonstrated a proper hemodynamic response to loading for the control group and patients with essential hypertension. CONCLUSION: The proposed approach demonstrates the ability of ICG-WT technique for adequate assessment of SV parameters, including cardiac time intervals.
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Abstract: BACKGROUND: Surgical site infection is one of the most common complications of conventional laparoscopic surgery. Preventing infection of the incision is particularly important. OBJECTIVE: To discuss how to prevent the occurrence of surgical site infection after contaminated abdominal surgery. METHODS: Five hundred and fifty-one surgery patients with ``contaminated abdominal incisions'' from January 2011 to May 2013 were analyzed in terms of the preventative treatment, and summarized for surgical site infection. Subcutaneous tissue flushed with normal saline + hydrogen peroxide before suturing in the intervention 1 group; subcutaneous tissue flushed with normal saline +…0.5% povidone-iodine before suturing in the intervention 2 group. RESULTS: When subcutaneous fat was contaminated to a depth of ≤ 2.5 cm, the rates of surgical site infection in the control group and the intervention groups showed no significant difference (P > 0.05). When subcutaneous fat was contaminated to a depth of ≥ 3.0 cm, the rate of surgical site infection in the control group compared with the intervention one group was not statistically different (P > 0.05). The rate of surgical site infection in the control group compared with the intervention two group was statistical significant (P < 0.05). The rate of surgical site infection in the intervention one group compared with the intervention two group was statistical significant (P < 0.05). CONCLUSIONS: Preoperative control of the blood sugar; correction of anemia and the hypoalbuminemia; use of intraoperative the high-frequency electrotome; irrigation of the incision with plenty of physiological saline +$ iodophor before suturing the subcutaneous fat layer were key to effectively preventing infection in contaminated abdominal incisions.
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Keywords: Surgical site infection, preventive treatment
Abstract: Functional magnetic resonance imaging (fMRI) is an important tool in neuroscience for assessing connectivity and interactions between distant areas of the brain. To find and characterize the coherent patterns of brain activity as a means of identifying brain systems for the cognitive reappraisal of the emotion task, both density-based k-means clustering and independent component analysis (ICA) methods can be applied to characterize the interactions between brain regions involved in cognitive reappraisal of emotion. Our results reveal that compared with the ICA method, the density-based k-means clustering method provides a higher sensitivity of polymerization. In addition, it is more sensitive to…those relatively weak functional connection regions. Thus, the study concludes that in the process of receiving emotional stimuli, the relatively obvious activation areas are mainly distributed in the frontal lobe, cingulum and near the hypothalamus. Furthermore, density-based k-means clustering method creates a more reliable method for follow-up studies of brain functional connectivity.
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Abstract: In order to ensure the safety and effectiveness of magnetic induction hyperthermia in clinical applications, numerical simulations on the temperature distributions and extent of thermal damage to the targeted regions must be conducted in the preoperative treatment planning system. In this paper, three models, including a thermoseed thermogenesis model, tissue heat transfer model, and tissue thermal damage model, were established based on the four-dimensional energy field, temperature field, and thermal damage field distributions exhibited during hyperthermia. In addition, a numerical simulation study was conducted using the Finite Volume Method (FVM), and the accuracy and reliability of the magnetic induction hyperthermia…model and its numerical calculations were verified using computer simulations and experimental results. Thus, this study promoted the application of computing methods to magnetic induction therapy and conformal hyperthermia, and improved the accuracy of the temperature field and tissue thermal damage distribution predictions.
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Keywords: Magnetic induction hyperthermia, numerical simulation, tissue thermal damage, FVM
Abstract: BACKGROUND: Despite medical progress worldwide, dental caries are still widespread. Miswak is derived from the plant Arak (Salvadora persica). It is used by Muslim peoples as a natural product for the cleansing of teeth, to ensure oral and dental hygiene. OBJECTIVE: This study was conducted to evaluate the antimicrobial effects of ethanol, methanol, and ethanol/methanol extracts of Miswak against three bacterial pathogens of the oral cavity. METHODS: The pathogens were isolated from the oral cavity of volunteers/patients and were identified on the basis of 16S rRNA gene amplification data. Sequence comparisons…were made with 16S rRNA gene sequences available in the GenBank database. RESULTS: The results of sequence alignment and phylogenetic analysis identified the three pathogens as being Staphylococcus aureus strain KKU-020, Enterococcus faecalis strain KKU-021 and Klebsiella pneumoniae strain KKU-022. All Miswak extracts showed powerful antimicrobial activity against the three pathogens. The maximum zone of inhibition (40.67 ± 0.88 mm) was observed against E. faecalis KKU-021 with ethanolic extracts whilst methanolic extracts showed the minimum zone of inhibition (10.33 ± 0.88 mm) against K. pneumonia KKU-022. CONCLUSION: Based upon the significant effects of the Miswak extracts, against the oral cavity pathogens in our study, we recommend that Miswak could be used as a dental hygiene method to prevent tooth caries.
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Abstract: BACKGROUND: The study of human walking patterns mainly focuses on how control affects walking because control schemes are considered to be dominant in human walking. OBJECTIVE: This study proposes that not only fine control schemes but also optimized body segment parameters are responsible for humans' low-energy walking. METHODS: A passive dynamic walker provides the possibility of analyzing the effect of parameters on walking efficiency because of its ability to walk without any control. Thus, a passive dynamic walking model with a relatively human-like structure was built, and a parameter optimization process based on…the gait sensitivity norm was implemented to determine the optimal mechanical parameters by numerical simulation. RESULTS: The results were close to human body parameters, thus indicating that humans can walk under a passive pattern based on their body segment parameters. A quasi-passive walking prototype was built on the basis of the optimization results. Experiments showed that a passive robot with optimized parameters could walk on level ground with only a simple hip actuation. CONCLUSION: This result implies that humans can walk under a passive pattern based on their body segment parameters with only simple control strategy implying that humans can opt to walk instinctively under a passive pattern.
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Keywords: Human walking, passive dynamic walking, parameters optimization, energy consumption