• The Korean Journal of Pain
• /
• v.21 no.3
• /
• pp.224-228
• /
• 2008

Ulnar nerve compression in the cubital tunnel is a common entrapment syndrome of the upper limb. Pulsed radiofrequency lesioning (PRFL) has been reported as a treatment method for relieving neuropathic pain. Since the placement of the electrode in close proximity to a targeted nerve is very important for the success of PRFL, ultrasound seems to be well suited for this technique. A 36-year-old woman presented with complaints of numbness and pain on the medial aspect of the elbow and the pain radiated down to the $4^{th}$ and $5^{th}$ fingers for 10 years after she suffered an elbow contusion, we then scheduled this woman for the ultrasound guided PRFL of the ulanr nerve. The initial ultrasound examination demonstrated a swollen nerve, loss of the fascicular pattern and an increased cross sectional area of the ulnar nerve. After confirmation of the most swollen site of the nerve via ultrasound, two sessions of PRFL were performed. The postprocedural 10 cm visual analog scale score decreased from 8 to 1 after the two sessions of PRFL.

• The Korean Journal of Pain
• /
• v.23 no.3
• /
• pp.198-201
• /
• 2010

Persistent and intractable hiccups (with respective durations of more than 48 hours and 1 month) can result in depression, fatigue, impaired sleep, dehydration, weight loss, malnutrition, and aspiration syndromes. The conventional treatments for hiccups are either non-pharmacological, pharmacological or a nerve block treatment. Pulsed radiofrequency lesioning (PRFL) has been proposed for the modulation of the excited nervous system pathway of pain as a safe and nondestructive treatment method. As placement of the electrode in close proximity to the targeted nerve is very important for the success of PRFL, ultrasound appears to be well suited for this technique. A 74-year-old man suffering from intractable hiccups that had developed after a coronary artery bypass graft and had continued for 7 years was referred to our pain clinic. He had not been treated with conventional methods or medications. We performed PRFL of the phrenic nerve guided by ultrasound and the hiccups disappeared.

• The Journal of Korea Robotics Society
• /
• v.15 no.1
• /
• pp.62-69
• /
• 2020

This paper proposes a pattern recognition and classification algorithm based on a circular structure that can reflect the characteristics of the sEMG (surface electromyogram) signal measured in the arm without putting the placement limitation of electrodes. In order to recognize the same pattern at all times despite the electrode locations, the data acquisition of the circular structure is proposed so that all sEMG channels can be connected to one another. For the performance verification of the sEMG pattern recognition and classification using the developed algorithm, several experiments are conducted. First, although there are no differences in the sEMG signals themselves, the similar patterns are much better identified in the case of the circular structure algorithm than that of conventional linear ones. Second, a comparative analysis is shown with the supervised learning schemes such as MLP, CNN, and LSTM. In the results, the classification recognition accuracy of the circular structure is above 98% in all postures. It is much higher than the results obtained when the linear structure is used. The recognition difference between the circular and linear structures was the biggest with about 4% when the MLP network was used.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.20 no.1
• /
• pp.60-70
• /
• 2014

Purpose: Bedside electrocardiograph (ECG) monitoring is continuously used for assessing patients' cardiac status in intensive care units. However, it has not been explored whether it is used with proper knowledge and nursing practices; if not, its usage will be limited and the risk for compromised patient safety might be significant. This study, therefore, explored knowledge and nursing practices regarding bedside ECG monitoring in nurses working at intensive care units. Methods: Participants in this survey research were a convenience sample of 156 nurses from 25 intensive care units distributed in five hospitals with more than 1,000 beds each in Seoul, South Korea. Results: Participants showed limited and incorrect knowledge and nursing practices. Only 4 (2.6%) participants correctly answered to all electrode placement sites of RA, LA, LL, and V1. Lead II was the most frequently monitored unit regardless of the main purpose of ECG monitoring, and nursing practices to manage noisy signals did not include skin care at the top priorities. Conclusion: Educators and clinicians alike need to make an effort to ensure that a safe level of knowledge and practices for the monitoring is maintained in order to make sure that patient outcomes are not compromised.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.11
• /
• pp.1205-1211
• /
• 2011

In this paper, we developed a pacemaker that can increase the efficacy of a left ventricular assist device (LVAD) and increase the survival rate for patients suffering end-stage heart failure. Because LVAD patients can experience arrhythmia, the pacemaker incorporated into the LVAD has the important role of sustaining sufficient blood circulation during arrhythmia. The electrode of the pacemaker is located at the apex of the left ventricle, where the VAD's inlet cannula is connected. This is efficient placement, in that the electrode can transmit electrical stimulation directly to the Purkinje fibers of the myocardium. The pacemaker can change the stimulation rate from 0 bpm to 191.4 bpm when a button is pressed on the external control module, and the pacemaker normally stimulates the heart at 60 bpm with 0.25 J of energy. We performed animal experiments to evaluate the performance and reliability of the combination of the LVAD and pacemaker. At pacemaker stimulation rates of 86.4 bpm, 100.2 bpm, 126.6 bpm, we recorded the ECGs, aortic pressures, and flow rates to analyze the heart loads.

• The Korean Journal of Pain
• /
• v.18 no.2
• /
• pp.263-266
• /
• 2005

The ganglion impar is a solitary retroperitoneal structure at the caudal end of the paravertebral sympathetic chain. Block of this ganglion has been advocated as a means of managing intractable perineal pain. In 1990, Plancarte et al performed a neurolytic block of the ganglion impar using 4-6 ml of 10% phenol through the intergluteal skin over the anococcygeal ligament. However, technical difficulties are encountered with the placement of the needle while performing this technique, with complications from the injection of phenol also being a possibility. In 1995, a modified approach for blocking the ganglion impar through the sacrococcygeal ligament was introduced by Wemm and Saberski. We used a radiofrequency (RF) lesion generator to create a controlled and localized lesion with a lower incidence of neural damages compared to chemical neurolysis. RF thermocoagulation of the ganglion impar through the sacrococcygeal ligament was performed on a 70-year-old male patient with constant anal pain using a curved TEW electrode. The patient has been relieved of his pain, without serious complication. Therefore, this technique may be an easier and safer approach, which is associated with fewer chances of complications.

• Composites Research
• /
• v.28 no.6
• /
• pp.383-388
• /
• 2015

Ionic Polymer-Metal Composite (IPMC) consisting of soft membrane plated by platinum electrode layers on both surfaces generates electric energy when subjected to various mechanical stimuli. The paper proposes a circuit model that describes the physical composition of IPMC to predict the voltage generation characteristic corresponding to bending motion. The parameter values in the model are identified to minimize the RMS error between the real and simulated outputs. Following the design of IPMC circuit model, the state observer of the model is designed by using pole placement technique which improves the model accuracy. State observer design technique is also applied to find the inverse model which estimates the input bending angles from the output voltage data. The results show that the inverse model estimates input bending angles fairly well enough for the further applications of IPMC not only as an energy harvester but also as a bending sensor.

• Particle and aerosol research
• /
• v.19 no.2
• /
• pp.21-30
• /
• 2023

Solar cells, converting abundant solar energy into electrical energy, are considered crucial for sustainable energy generation. Recent advancements focus on nanoparticle-enhanced solar cells to overcome limitations and improve efficiency. These cells offer two potential efficiency enhancements. Firstly, plasmonic effects through nanoparticles can improve optical performance by enhancing absorption. Secondly, nanoparticles can improve charge transport and reduce recombination losses, enhancing electrical performance. However, factors like nanoparticle size, placement, and solar cell structure influence the overall performance. This study evaluates the performance of silver nanoparticles incorporated in a p-i-n structure of perovskite solar cells, generated via aerosol state by the evaporation and condensation system. The silver nanoparticles deposited between the hole transport layer and transparent electrode form nanoparticle embedded transport layer (NETL). The evaluation of the optoelectronic properties of perovskite devices using NETL demonstrates their potential for improving efficiency. The findings highlight the possibility of nanoparticle incorporation in perovskite solar cells, providing insights for sustainable energy generation.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.8
• /
• pp.117-125
• /
• 2015

In this paper, we propose a classification algorithm based on the obtained EEG(Electroencephalogram) signal for the control of 'left' and 'right' turnings of which a driving system composed of EEG sensor, Labview, DAQ, Matlab and driving robot. The proposed algorithm uses features extracted from frequency band information obtained by DWT (Discrete Wavelet Transform) and selects features of high discrimination by using Fisher score. We, also propose the number of feature vectors for the best classification performance by using SVM(Support Vector Machine) classifier and propose a decision pending algorithm based on MLD (Maximum Likelihood Decision) to prevent malfunction due to misclassification. The selected four feature vectors for the proposed algorithm are the mean of absolute value of voltage and the standard deviation of d5(2-4Hz) and d2(16-32Hz) frequency bands of P8 channel according to the international standard electrode placement method. By using the SVM classifier, we obtained 98.75% accuracy and 1.25% error rate. Also, when we specify error probability of 70% for decision pending, we obtained 95.63% accuracy and 0% error rate by using the proposed decision pending algorithm.

• Restorative Dentistry and Endodontics
• /
• v.22 no.1
• /
• pp.111-131
• /
• 1997

Eighty two of extracted bovine mandibular incisors were sectioned transversely through the cementoenamel junction(CEJ) and instrumented to a size minimum-# 110 file at the working length by 5.25 % NaOCl irrigation. The roots in group 1 were received a final irrigation with 10ml of 17% EDTA followed by 10ml of 5.25% NaOCl, group 2, 10ml of 40% citric acid followed by 10ml of 5.25% NaOCl, group 3, 20ml of 5.25% NaOCl, and control group, 20ml distilled water. Canal walls of four roots in each group and control group were examined by SEM(x3000). Calcium hydroxide was placed into all experimental roots except control group. Each root was placed in nalgen bottle containing unbuffered distilled water. The pH level of the medium surrounding tooth was recorded at 0, one hour, and daily for 1week, then 14days, 21days, and 28days using pH electrode. At 1, 3, 7, 14, 21days, and 28days, four roots from each group were split longitudinally and the ratio change was recorded using spectroiluorometer. The results were followings : 1. The smear layer was totally removed from canal walls in group 1 and 2, but was observed in group 3 and control group. 2. The hydroxyl ion diffused more rapidly through radicular dentin when smear layer was removed from canal walls. 3. The hydroxyl ion derived from calcium hydroxide began to diffuse from the root canal to the exterior surface of the root at 1day, and continued to 1-2weeks. 4. The pH level of dentin near the CEJ was not different in all experimental group regardless of presence of smear layer. It is clinically advisable to place calcium hydroxide into root canal for 1-2weeks for the purpose of expectation of diffusion of hydroxyl ion. But, after the placement of calcium hydroxide into root canal, the consequent pH level of external root surface will be futher studied with respect to it's effect on the root and periodontium.