Chiyul Yoon

Measurement of Shoulder Range of Motion in Patients with Adhesive Capsulitis Using a Kinect

Range of motion (ROM) measurements are essential for the evaluation for and diagnosis of adhesive capsulitis of the shoulder (AC). However, taking these measurements using a goniometer is inconvenient and sometimes unreliable. The Kinect (Microsoft, Seattle, WA, USA) is gaining attention as a new motion detecting device that is nonintrusive and easy to implement. This study aimed to apply Kinect to measure shoulder ROM in AC; we evaluated its validity by calculating the agreement of the measurements obtained using Kinect with those obtained using goniometer and assessed its utility for the diagnosis of AC. Both shoulders of 15 healthy volunteers and affected shoulders of 12 patients with AC were included in the study. The passive and active ROM of each were measured with a goniometer for flexion, abduction, and external rotation. Their active shoulder motions for each direction were again captured using Kinect and the ROM values were calculated. The agreement between the two measurements was tested with the intraclass correlation coefficient (ICC). Diagnostic performance using the Kinect ROM was evaluated with Cohen’s kappa value. The cutoff values of the limited ROM were determined in the following ways: the same as passive ROM values, reflecting the mean difference, and based on receiver operating characteristic curves. The ICC for flexion/abduction/external rotation between goniometric passive ROM and the Kinect ROM were 0.906/0.942/0.911, while those between active ROMs and the Kinect ROMs were 0.864/0.932/0.925. Cohen’s kappa values were 0.88, 0.88, and 1.0 with the cutoff values in the order above. Measurements of the shoulder ROM using Kinect show excellent agreement with those taken using a goniometer. These results indicate that the Kinect can be used to measure shoulder ROM and to diagnose AC as an alternative to goniometer.

Manikin-Integrated Digital Measuring System for Assessment of Infant Cardiopulmonary Resuscitation Techniques

The process of cardiopulmonary resuscitation (CPR) involves various components that must be followed to deliver high quality of CPR. While the components commonly apply to CPR for all ages from infant to adult, there are several different suggestions for infant CPR such as two-thumb CPR and two-finger CPR. However, the comprehensive evaluation based on all these components has been difficult in the absence of proper evaluation tool. Here, we developed a new manikin-integrated, digital measuring system that objectively estimates overall performance of infant CPR by evaluating individual CPR components one by one including different hand placements. The system collects and analyzes data to present estimations in digital scores according to a new evaluation index constructed based on the previously verified one. The feasibility of the system was validated through simulations with beginners and experts in first aid, resulting in statistically significant differences between the two groups with the indication of specific weaknesses for each group which may provide a basis for creating customized CPR training strategy in compliance with the personal level. We believe that the system would become a valuable assessment tool not only for infant CPR but also for the CPR technique, in general, by reflecting every component in the evaluation.

Heart Rate Tracking Using a Doppler Radar With the Reassigned Joint Time-Frequency Transform

Heart rate variations are tracked using an RF Doppler signal by applying a reassigned joint time-frequency transform (RJTFT). In time-frequency analysis, RJTFT improves the readability of the heart rate on a spectrogram and the heart rate is continuously tracked with it. To verify the result, a heartbeat signal was acquired from a stationary human subject using a Doppler radar unit. The sensor operating at 2.45 GHz was located a distance of 0.5 m from the subject. Using the RJTFT, the heart rate was clearly extracted, thereby improved the readability. A reference heart rate was measured by a photoplethysmography (PPG) device and compared with the heart rate tracked by the RJTFT. The resulting root mean square (RMS) difference of the heart rate measured by the two methods was 5%.

Development and evaluation of an automatic acne lesion detection program using digital image processing

Existing acne grading methods, which depend on overall impression, require a long training period and there is a high degree of variability among raters, including trained dermatologists. The use of lesion count provides fair reproducibility but the method is time consuming. New technologies in photographic equipment and software allow solutions to the problem of acne evaluation. This study was conducted to develop the automatic acne lesion program and evaluation of its usefulness.

The temperature dependence of conductivity anisotropy in intermediately doped polyacetylene

Abstract The temperature dependence of electrical conductivity and conductivity anisotropy of FeCl 3 doped stretch-oriented polyacetylene film at different doping levels were measured by using Montgomery technique. The increase of conductivity anisotropy upon doping is related to the aligned fibrillar structure and the interfibrillar contact effect. Weak temperature dependence, the slight decrease at low temperature and the persistence of anisotropy through aging indicate that the interfibrillar contact barriers limit the quasi-one-dimensional charge transport in heavily doped polyacetylene and play a major role in the conductivity anisotropy.

Thermoelectric power and conductivity of the stretch-oriented polyacetylene film doped with MoCl5

Abstract Thermoelectric power (TEP) and Montgomery conductivity are measured for the various concentrations of the MoCl 5 doped stretch-oriented polyacetylene film synthesized using the heat treated catalysts. The obtained maximum conductivity is σ ∥ (RT)=6400 S/cm along the oriented direction. Its anisotropy is σ ∥ / σ ⊥ = 25 and temperature independent. Temperature dependence of TEP is quasi-linear in the heavily doped regime. However, the extrapolated T=O intercept value of TEP changes from positive to negative as the doping concentration increases. Similar cross over behavior was also observed in NbCl 5 doped polyacetylene but not in FeCl 3 and ZrCl 4 doped ones. The electron-phonon interaction and the Kondo effect like coupling mechanism are discussed to compare with the observed results.

Tool to visualize and evaluate operator proficiency in laser hair-removal treatments

BackgroundThe uniform delivery of laser energy is particularly important for safe and effective laser hair removal (LHR) treatment. Although it is necessary to quantitatively assess the spatial distribution of the delivered laser, laser spots are difficult to trace owing to a lack of visual cues. This study proposes a novel preclinic tool to evaluate operator proficiency in LHR treatment and applies this tool to train novice operators and compare two different treatment techniques (sliding versus spot-by-spot).MethodsA simulation bed is constructed to visualize the irradiated laser spots. Six novice operators are recruited to perform four sessions of simulation while changing the treatment techniques and the presence of feedback (sliding without feedback, sliding with feedback, spot-by-spot without feedback, and spot-by-spot with feedback). Laser distribution maps (LDMs) are reconstructed through a series of images processed from the recorded video for each simulation session. Then, an experienced dermatologist classifies the collected LDMs into three different performance groups, which are quantitatively analyzed in terms of four performance indices.ResultsThe performance groups are characterized by using a combination of four proposed indices. The best-performing group exhibited the lowest amount of randomness in laser delivery and accurate estimation of mean spot distances. The training was only effective in the sliding treatment technique. After the training, omission errors decreased by 6.32% and better estimation of the mean spot distance of the actual size of the laser-emitting window was achieved. Gels required operators to be trained when the spot-by-spot technique was used, and imposed difficulties in maintaining regular laser delivery when the sliding technique was used.ConclusionsBecause the proposed system is simple and highly affordable, it is expected to benefit many operators in clinics to train and maintain skilled performance in LHR treatment, which will eventually lead to accomplishing a uniform laser delivery for safe and effective LHR treatment.

A grip force model for the da Vinci end-effector to predict a compensation force

A torque transfer system (TTS) that measures grip forces is developed to resolve a potential drawback of the current da Vinci robot system whose grip forces vary according to the different postures of its EndoWrist. A preliminary model of EndoWrist Inner Mechanism Model (EIMM) is also developed and validated with real grip force measurements. EndoWrist’s grip forces, posture angles, and transferred torque are measured by using TTS. The mean measured grip forces of three different EndoWrist for 27 different postures were very diverse. The EndoWrist exerted different grip forces, with a minimum of 1.84-times more and a maximum of 3.37-times more in specific posture even if the surgeon exerted the same amount of force. Using the posture angles as input and the grip forces as output, the EIMM is constructed. Then, expected grip force values obtained from EIMM are compared with actual measurements of da Vinci EndoWrist to validate the proposed model. From these results, surgeons will be beneficial with the understandings of actual grip force being applied to tissue and mechanical properties of robotic system. The EIMM could provide a baseline in designing a force-feedback system for surgical robot. These are significantly important to prevent serious injury by maintaining a proper force to tissue.

Patch type integrated sensor system for measuring electrical and mechanical cardiac activities

The ElectroMechanical Film (EMFi), a thin and flexible piezoelectric material, has been widely used as a mechanical sensor or actuator. Especially in Biomedical Engineering field, many researchers have used EMFi for measuring ballistocardiogram (BCG) which is a mechanical signal caused by blood ejection from heart. However, previous methods required special equipments installed on a chair or a bed to measure BCG. In this preliminary study, we designed a flexible patch type sensor that can measure electrical and mechanical signal simultaneously on a single unit. The Ballistocardiogram-Electrocardiogram patch (BEpatch), integrated with flexible circuit and attached to chest, can successfully measure fine electrocardiogram (ECG) and BCG signals simultaneously. The result shows that BEpatch can be used for continuous monitoring of bio-signals in a simple and comfortable manner, thereby, advantageous as a wearable health care device.

An assessment of the accuracy of a novel weight estimation device for children

Background We sought to validate the accuracy and assess the efficacy of a newly developed electronic weight estimation device (ie, the rolling tape) for paediatric weight estimation. Methods We enrolled a convenience sample of children aged <17 years presenting to our emergency department who volunteered to participate in the study. The childrens heights and weights were measured, and three researchers estimated these values using the rolling tape and Broselow tape at 5 min intervals. The weight estimates of researcher 1, researcher 2 and the Broselow tape were compared with measured values, and mean percentage error (MPE), root mean square error (RMSE) and percentage of estimates within 10% of the actual measured values were calculated. For 30 randomly selected subjects, we compared the time interval from the start of the measurement to the time that orders for epinephrine, defibrillation dose and instrument size could be given in a simulated arrest scenario. Results We enrolled 906 children (median age 4.0 years). For researcher 1, researcher 2 and the Broselow tape, MPE values were 0.11% (RMSE 2.61 kg), 1.41% (RMSE, 2.61 kg) and 1.72% (RMSE 5.41 kg), respectively, and the percentages of children with predictions within 10% of their actual weight were 75.1%, 75.7% and 60.6%, respectively. In the 30 simulated cases, the mean time for measurement to ordering was significantly shorter (25.8 s vs 35.5 s, p<0.001) for the rolling tape compared with the Broselow tape method. Conclusions The rolling tape is a good weight estimation tool for children compared with other methods. The rolling tape method significantly decreased the time from weight estimation to orders for essential drug dose, instrument size and defibrillation dose for resuscitation.