• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.410-415
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• 1999

Yakju was sterilized with high-voltage pulses of short time of a continuous pulsed electric field (PEF) system. The initial microbial counts of Yakju were $2.2{\times}10^{5}$ CFU/mL for total aerobes. The pH, acidity and electric conductivity of Yakju were 3.82, 0.37% and 1.24 mS/cm, respectively. Yakju was treated with exponential-wave formed electric pulses of 100 Hz for $0{\sim}4000{\mu}s$ under the field strength of $20{\sim}35\;kV/cm$. The lethal effect of electric fields on microorganisms was resulted from the breakdown of the cell membrane induced by the transmembrane electric potential. The critical values of the external field for the sterilization were 16.0 kV/cm for total aerobes. Logarithmic survival rates decreased linearly at low electric field strength, but curvilinearly at high electric field strength with treatment time. The sterilization of Yakju was more largely affected by the electric field strength than by the treatment time. Any changes in pH, acidity, and the growth of microorganisms were not found in the PEF treated Yakju during the storage at both $4^{\circ}C\;and\;30^{\circ}C$.

• Clean Technology
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• v.24 no.2
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• pp.135-145
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• 2018

There are various activities for reduction of the greenhouse gasses (GHG) emission around the world. The countries agreed to submit their's individual plans to the United Nations and have operated programs related to the Climate Change, in addition, the enterprises have spontaneously been developed individual calculation methodologies of GHG emission. This paper aims at examining methods for calculating the effect of the reduction of environmental impact, being divided into three categories; international standard, country, enterprise. The reduction effects of environmental impact were compared by applying an existing product of the vehicle undercover and the uni-materialized product and being selected six calculation methods of environmental footprint. There are significant differences according to the evaluation methods of product environmental footprint (PEF) reduction. Main factors of differences are a gap in system boundary, a scope of data collection and the replacement amount standard of existing products. Stakeholders are unreliable in the results of PEF reduction because of the differences in results by each methodology. Therefore, it is necessary to disclose in detail the methodologies of calculating the PEF reduction that relevant people can easily understand, also to enable comparisons of the reduction results by developing the standardization of evaluation methods of PEF in the long term.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1175-1183
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• 1997

Lethal effects of high voltage pulsed electric fields (PEF) on suspensions of Lactobacillus plantarum cells in phosphate buffer solution were examined by using continuous recycle treatment system. Critical electric field strength and treatment time needed for inactivation of L. plantarum were 13.6 kV/cm and $16.1\;{\mu}s$ at room temperature, respectively. As decrease in frequency (decreasing pulse number), the degree of inactivation of L. plantarum was increased. A 2.5 log reduction in microbial population could be achieved with an electric field strength of 80 kV/cm, 300 Hz frequency and $2000\;{\mu}s$ treatment time. Survivability was decreased with increase in total treatment time (cycle number) and frequency at the same cycle number. As sterilization model of continuous recycle PEF treatment, $logS=-N_m\;log\;m+B$ and $N_m=k_1\;P_n+k_2$ were established. This model was very well fitted to tile empirical data. The rate of inactivation increased with increase in the processing temperature. The maximum reduction in survivability (5.6 log reduction) was obtained with 80 kV/cm electric field strength at $50^{\circ}C$ for $1000\;{\mu}s$ treatment.

• Korean Journal of Radiology
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• v.23 no.11
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• pp.1102-1111
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• 2022

Objective: To evaluate the ultrasonography (US) features for diagnosing metastasis in cervical lymph nodes (LNs) in patients with thyroid cancer and compare the US classification of risk of LN metastasis between European and Korean guidelines. Materials and Methods: From January 2014 to December 2018, US-guided fine-needle aspiration was performed on 836 LNs from 714 patients for the preoperative nodal staging of thyroid cancer. The US features of LNs were retrospectively reviewed for the following features: size, presence of hilum, margin, orientation, cystic change, punctate echogenic foci (PEF), large echogenic foci, eccentric cortical thickening, abnormal vascularity, and cortical hyperechogenicity. A multiple logistic regression analysis was performed to identify the independent US features for the diagnosis of metastatic LNs. The diagnostic performance of independent US features was subsequently evaluated. LNs were categorized according to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and European Thyroid Association (ETA) guidelines, and the correlation between the two sets of classifications was assessed. Results: Absence of the hilum, presence of cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features of metastatic LNs. Cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity showed high specificity (86.8%-99.6%). The absence of the hilum had the highest sensitivity yet low specificity (66.4%). When LNs were classified according to the ETA guidelines and K-TIRADS, they yielded similar categorizations of malignancy risks and were strongly correlated (Spearman coefficient, 0.9766 [95% confidence interval, 0.973-0.979]). According to the ETA guidelines, 9.8% (82/836) of LNs were classified as "not specified." Conclusion: Absence of hilum, cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features suggestive of metastatic LNs in thyroid cancer. Both K-TIRADS and the ETA guidelines provided similar risk stratification for metastatic LNs with a high correlation; however, the ETA guidelines failed to classify 9.8% of LNs into a specific risk stratum. These results may provide a basis for revising LN classification in future guidelines.

• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.374-378
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• 2013

Purpose: Human body have biological rhythmic pattern in a day, which is affected by internal and external environmental factors. We investigated whether respiratory function was fluctuated according to the influence of time-of-day (around at 9 am, 1 pm, and 6 pm) in health subjects, using pulmonary function test (PFT). Methods: Eighteen healthy volunteers (8 men, mean ages; $22.4{\pm}1.6$, mean heights; $166.61{\pm}9.60$, mean weight; $59.3{\pm}10.3$) were recruited. Pulmonary function test (PFT) was measured at three time points in day, around 9 am, 1 pm, and 6 pm in calm research room with condition of under 55dB noise level, using a spirometer (Vmax 229, SensorMecis, USA). Forced vital capacity (FVC), forced expiratory volume at one second (FEV1), FVC/FEV1, and peak expiratory flow (PEF) were acquired. Results: In comparison of raw value of PFT among three time points, subjects showed generally better respiratory function at 9 am, than at other points, although no significance was found. In comparison of distribution of ranking for respiratory function in each individual, only PEF showed significant difference. In general, distributional ratio of subjects who showed best performance of respiratory function in a day was high. Conclusion: These findings showed that circadian rhythm by diurnal pattern was not detected on respiratory function throughout all day. But, best performance on respiratory function was observed mostly in the morning, although statistical significance did not exist.

• The Journal of Korean Physical Therapy
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• v.24 no.5
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• pp.340-347
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• 2012

Purpose: This study was conducted in order to investigate the effect on respiratory function, trunk control, and functional activities of daily living (ADL) through respiratory muscle strength training in patients with chronic stroke. Methods: Eighteen subjects who were six months post stroke participated in this study. The subjects were randomly allocated to two groups: experimental (n=10) and control (n=8). Both groups received physical therapy for five sessions, 30 minutes per week, during a period of six weeks. Subjects in the experimental group participated in an additional respiratory muscle strength training program, in which the threshold PEP device was used for 30 minutes per day, three days per week, during a period of six weeks. Results from pretest-posttest control were evaluated by pulmonary function forced vital capacity (FVC), forced expiratory volume at one second (FEV1), FEV1/FVC, peak expiratory flow (PEF), capacity of cough, trunk control, and functional ADL. Results: Significant improvement in the FEV1, PEF of pulmonary function (p<0.05), cough function (p<0.05), and trunk control (p<0.05) was observed among the groups. Conclusion: Respiratory muscle strength training improves pulmonary function, capacity of cough, and trunk control. These results suggest that respiratory muscle strength training is feasible and suitable for individuals with chronic stroke.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.311-315
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• 2013

Purpose: Forward head posture is a typical symptom in people who use computers for long periods of time. Respiration is a complex function involving co-operation of muscular, skeletal, and nervous systems. Abnormal posture can have a negative effect on respiratory function. The purpose of this study was to investigate the relationship between forward head posture and respiratory function in young adults. Methods: Forty-six healthy subjects participated in this study. Craniovertebral angle was measured for assessment of the forward head posture. The respiratory function of all subjects was evaluated by measuring forced vital capacity (FVC), forced expiratory volume at one second (FEV1), forced expiratory volume at one second/forced vital capacity (FEV1/FVC) ratio, and peak expiratory flow (PEF). The baseline of forward head posture was less than 49 degrees. Results: : Significant differences for predicted FVC and FEV1 were observed between the two groups, however, no statistically significant differences in FEV1/FVC ratio and PEF were observed between the two groups. Conclusion: Results of this study demonstrate that forward head posture has a negative effect on respiratory function in young adults.

• Journal of Sensor Science and Technology
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• v.13 no.2
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• pp.79-84
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• 2004

Asthma is one of the important respiratory diseases requiring home self care usually performed by commercialized peak expiratory flow meter (PEFM). However, this simple device can measure only single parameter, PEF, due to its purely mechanical principle, significantly limiting desease management quality. The present study introduced a new expiratory flow measurement technique by miniatured air expansion chamber easily installed within PEFM. Continuous pressure signal obtained from the chamber demonstrated an accurate quadratic relationship with flow. The volume measurement error was $<{\pm}1%$ well within the American Thoracic Society (ATS) criteria of 3%. Important spirometric parameters of FVC, PEF, and FEF25-75% were all accurately estimated with correlation coefficients > 0.95. The present technique obtains continuous expiratory air flow signal, making possible and convenient to perform spirometric test at home. Electronic interface capability would be also useful for remote asthma management.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.738-741
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• 2009

본 논문에서는 RAW 이미지 포맷 중 PEF, MRW에 대한 분석 결과와 RAWImage Viewer에 대해 소개한다. DSLR 디지털 카메라로 촬영되는 이미지 파일은 범용의 JPEG 포맷이나 제조사별 독자적인 RAW 이미지 포맷으로 저장된다. 이러한 RAW 이미지 파일을 PMP 등의 휴대용 멀티미디어 기기나 디지털액자에서 재생 및 확인하기 위한 요구가 증대되고 있다. 하지만, RAW 이미지 포맷이 디지털 카메라 제조사별로 다르고, 해당 포맷에 대한 구체적인 정보가 공개되지 않아 대부분의 휴대용 멀티미디어 기기에서 RAW 이미지 파일 재생 기능을 완벽하게 지원하지 못하고 있다. 본 논문에서는 RAW 이미지 파일 포맷을 분석하여 다양한 임베디드 멀티미디어 기기에서 모든 RAW 이미지 파일을 지원할 수 있는 라이브러리 구축을 위한 연구 결과 중 일부를 소개한다. Cannon의 CRW, CR2 포맷과 Nikon의 NEF 분석 결과에 이어 PEF, MRW에 대한 분석 결과와 RAW 이미지 출력 및 분석 기능이 포함된 RAWImage Viewer에 대해 설명한다. 연구 결과는 RAW 파일을 재생할 수 있는 임베디드 장비 및 PC용 RAW 이미지 파일 재생 라이브러리를 구축 및 응용 프로그램 개발시 활용될 것이다.

• Journal of International Academy of Physical Therapy Research
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• v.8 no.2
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• pp.1146-1151
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• 2017

The purpose of this study was to compare the effects of respiratory exercise on cardiopulmonary function and muscle activity of rectus abdominis in smokers and non-smokers with elderly people. All the participants were older than 65 years, and twenty non-smokers, and twenty smokers participated. Non-smokers and smokers were randomly divined into 10 feedback breathing exercises (FBE) and a balloon-blowing exercise (BBE) group. The FBE and the BBE were performed three times a week for four weeks. Forced vital capacity (FVC), forced expiratory volume at one second (FEV1), forced expiratory volume at one second/forced vital capacity (FEV1/FVC), peak expiratory flow (PEF), and vital capacity (VC) were measured as pulmonary function. EMG was used to measure the activity of the rectus abdominis. In the FBE and BBE groups, $FEV_1$ was significantly lower in non-smokers compared to smokers at two and four weeks (p<.05), $FEV_1/FVC$, PEF and VC were significantly lower in non-smokers compared to smokers to pre-test, two weeks, four weeks and six weeks (p<.05). Muscle activity of rectus abdominis was significantly difference in the BBE group at pre-test, two weeks, four weeks, and six weeks (p<.05). These results suggest that respiratory exercise was effective in improving pulmonary function and rectus muscle activity.