• Tuberculosis and Respiratory Diseases
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• v.56 no.2
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• pp.144-150
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• 2004

Background : An assessment of the presence and the degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. However, the time responses of spirometric parameters in response to bronchodilator have not been well investigated. Methods: We studied 15 patients with asthma. Spirometric and mini-Wright peak expiratory flow measurements were performed at 15, 30, 45, and 60 minutes after using single dose($200{\mu}g$) of inhaled bronchodilator, salbutamol. Results : The mean values of forced expiratory volume in one second($FEV_1$) and forced vital capicaty(FVC) were significantly increased at 60 minutes after using bronchodilator in comparison to 15 minutes. And peak expiratory flow rate measured by either mass flow sensor or mini-Wright peak flow meter were significantly increased at 45 minutes after using bronchodilator in comparison to 15 minutes. Conclusions : To appropriate evaluation of the bronchodilator response in patients with reversible airflow limitation, it would be useful measuring either $FEV_1$ or PEF at the later time point 60 or 45 minutes in comparison to 15 minutes after using bronchodilator.

• Phonetics and Speech Sciences
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• v.5 no.1
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• pp.19-26
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• 2013

The aerodynamic characteristics (subglottal pressure (Ps) and mean airflow rate (MFR)), fundamental frequency (Fo), intensity (I), vocal efficiency (VE), and closed quotient (CQ) were compared during a sustained vowel /o/ sound under three conditions: in a comfortable loudness and pitch level (condition 1), in a maximum loudness level with a fixed pitch (condition 2), and in a maximum loudness level without a fixed pitch (condition 3). Also, multiple regression analyses were done to measure the aerodynamic characteristics affect on the VE and the CQ in each condition. The results showed the Fo, Ps, MFR, VE, and CQ increased as I increased with and without fixed pitch. Most notably, VE in condition 3 was the highest of all the conditions, but CQ was not very high. By the results of multiple regression analysis, VE was significantly affected by I and Ps in all conditions; Fo was the other main key for affecting VE in high pitch. However, none of the aerodynamic characteristics significantly affected CQ. As I increases, Fo should be increased by increasing Ps and VE. Therefore, researchers should consider and specify an a priori to Fo, Ps, and I when measuring VE to examine the complex and delicate vocal mechanism.

• Phonetics and Speech Sciences
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• v.10 no.4
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• pp.135-146
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• 2018

The Modified Voiced Lip Trill (MVoLT) training is a variant of voiced lip-till training characterized by increased loudness, lowered laryngeal position, and lip contact facilitated with fingers. The purpose of the current study was to assess the effect of the MVoLT training program on vocal changes of musical singing theater students. A total of 32 musical theater students (17 males and 15 females, age ranging from 18 to 29) participated in the study. For about three months, each participant was tutored using a systematic program focussing on the MVoLT training, accompanied by certain facilitating strategies. Pre- & post-training multi-dimensional vocal characteristics were assesed and compared. Results showed that cepstral peak prominence during vowel phonation increased after training, while its standard deviation and Cepstral Spectral Index of Dysphonia decreased. When an aerodynamic assessment was performed, maximum phonation time, subglottal pressure, mean airflow rate increased, while electroglottographic measures did not change. In addition, decreased psychometric measures, higher maximum pitch, and increased vocal range were noted after training. In conclusion, the MVoLT was proven to have a potential as an effective and safe training method for musical theater singing.

• Korean Journal of Plant Resources
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• v.29 no.6
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• pp.670-678
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• 2016

We compared the germination rate of dehisced ginseng (Panax ginseng) seeds that were dried under two different conditions, slowly at $15^{\circ}C$ [relative humidity (RH) 10-12%] and rapidly under a laminar airflow cabinet at $25^{\circ}C$ (RH 22-25%). The measurements showed that drying rate and seed moisture content (SMC) play important roles in storage ability and vigor. The seeds that were dried rapidly at $25^{\circ}C$ showed high GR compared with the seeds that were dried at $15^{\circ}C$ after 6 and 12 months of storage at $-80^{\circ}C$ irrespective of MC. Seeds dried slowly at $15^{\circ}C$ with MC higher than 7.0% showed high GR maintenance after storage at $-18^{\circ}C$ and at $4^{\circ}C$ in comparison with rapidly dried seeds. However, the GR of the slowly desiccated seeds decreased as mean SMC was reduced to less than 5.0%, whereas the rapidly dried seeds were distinguished by significantly high GR irrespective of the storage conditions. The ginseng seeds desiccated under different conditions showed differences in storage performance. Seeds with 7-9% MC that were dried slowly at $15^{\circ}C$ for 5-7 days showed high GR after $4^{\circ}C$ and $-18^{\circ}C$ storage; however, longer periods of desiccation decreased the germination level remarkably compared with that of rapidly dried seeds.

• Korean Journal of Food Science and Technology
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• v.14 no.3
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• pp.271-275
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• 1982

Low-temperature in-bin drying with high-moisture paddy were demonstrated and studied under local autumn weather condition. Paddy with the initial moisture content of about 24.5 percent in the steel storage bin(diameter: 3 m, height: 3.17 m) was uniformly dried to about 15 percent by continuous blowing of ambient air (average temperature: $10.5^{\circ}C$, RH: 58 percent) in the middle part of October. The amount of grain and grain height were 4.19 M/T and 90 cm, respectively. Total fan operation time was 288 hours and airflow rate was $4.81\;m^3/min/m^3$ of paddy. Mean drying rate was 0.03 percent per hour and enery requirement for fan operation was 0.38 KWh per kg water removed.

• Phonetics and Speech Sciences
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• v.3 no.1
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• pp.103-110
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• 2011

Idiopathic Parkinson's Disease patients' speech is hypokinetic dysarthria and their speech is possibly the consequence of impaired respiratory support. The purpose of this study was focused on the respiratory characteristics of speech breathing in de novo IPD who were not given prior vocal or anti-Parkinson treatment. A total of 40 subjects participated in the study: 20 de novo IPD patients between the ages of 50 and 80, and 20 normal subjects with similar age, height, and weight matches. Forced Expiratory Vital Capacity (FVC), Forced Expiratory Volume in 1 sec (FEV1) and $FEV_1$ as a percentage of FVC (FEV1/FVC) was measured with a PC-based spirometer (Cosmed). In addition, Maximum Phonation Time (MPT), Mean Airflow Rate (MFR), Subglottal Pressure (Psub) and the number of syllables produced per breath were measured with a Phonatory Aerodynamic System (Kay PENTAX). All subjects were asked to read a standardized Korean paragraph and the following measurements were obtained from the task. Results indicated no statistically significant differences in respiratory function (FEV1/FVC%) and aerodynamic function between the two groups, but the number of syllables per breath was significantly lower in the IPD patient group than in the normal group and it could be predicted by FVC and MFR. Therefore, the study shows that the MFR from the lungs during speech in de novo IPD patients is used inefficiently.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.1
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• pp.44-50
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• 2007

Background and Objectives: The 585-nm pulsed dye laser (PDL) has recently been adopted by otolaryngologists because of its epithelial-sparing properties. Many authors have reported the use of PDL for treatment of various vocal cord lesions. This purpose of this study is to examine the effectiveness of 585-nm PDL in the treatment of vocal polyp. Materials and Methods: Eight patients with vocal polyp were treated with 585-nm PDL from Sep. 2006 to Nov. 2006 in Yong-dong Sevrance hospital. 5 of them went through local anesthesia and 3 of them went through general anesthesia. In order to control laser fiber, flexible digital transnasal laryngoscope was applied under local anesthesia and general anesthesia using LMA, and micromanipulator was used under general anesthesia using endotracheal tube. The evaluations of vocal function was done at pre-and postoperation. Results: All patients improved in the perceptual evaluation of voice after PDL surgery. The aerodynamic study revealed that 5 of 8 patients showed improvement in maximal phonation time, and 6 of 8 showed improvement in mean airflow rate during phonation. The acoustic analysis revealed that all patients showed improvement in Jitter and Shimmer, and 7 of 8 showed improvement in noise to harmony ratio. Conclusion: This study demonstrates promising results in the efficacy of 585-nm PDL for the treatment of vocal polyps, and it illustrates a new option for vocal polyp treatment as well as the advantage of PDL surgery.

• Land and Housing Review
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• v.14 no.4
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• pp.111-120
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• 2023

Indoor air quality has become increasingly important with the increase in time spent in residential environments, impact of external fine dust, yellow dust, and the post-COVID 19 pandemic. Residential mechanical ventilation plays a key role in addressing indoor air quality. The legal standard for residential air changes per hour in Korea is 0.5 ACH. However, there are no standards for the location of supply and return vents. This study atempts to analyze the impact of ventilation performance based on the location of supply and return vents. An experiment was conducted using the CO₂ tracer gas concentration decay method in a mock-up house set inside a large chamber to minimize external influences. The experimental results indicated that the commonly used combination of 2 supply and 2 return vents in living room spaces had a lower mean age of air than the combination of 1 supply and 2 return vents. Using multiple supply and return vents had lower mean age of air than using just 1 supply and 1 return vent.

• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.379-388
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• 1994

Background : In sleep apnea syndrome, arterial oxygen saturation($SaO_2$) decreases at a variable rate and to a variable degree for a given apneic period from patient to patient, and various kinds of cardiac arrythmia are known to occur. Factors supposed to affect arterial oxygen desaturation during apnea are duration of apnea, lung voulume at which apnea occurs, and oxygen consumption rate of the subject. The lung serves as preferential oxygen source during apnea, and there have been many reports related with the influence of lung volume on $SaO_2$ during apnea, but there are few, if any, studies about the influence of oxygen consumption rate of an individual on $SaO_2$ during breath holding or about the profile of arterial oxygen resaturation after breathing resumed. Methods : To investigate the changes of $SaO_2$ and heart rate(HR) during breath holding(BH) and rebreathing(RB) and to evaluate the physiologic factors responsible for the changes, lung volume measurements, and arterial blood gas analyses were performed in 17 healthy subjects. Nasal airflow by thermistor, $SaO_2$ by pulse oxymeter and ECG tracing were recorded on Polygraph(TA 4000, Gould, U.S.A.) during voluntary BH & RB at total lung capacity(TLC), at functional residual capacity(FRC) and at residual volume(RV), respectively, for the study subjects. Each subject's basal metabolic rate(BMR) was assumed on Harris-Benedict equation. Results: The time needed for $SaO_2$ to drop 2% from the basal level during breath holding(T2%) were $70.1{\pm}14.2$ sec(mean${\pm}$standard deviation) at TLC, $44.0{\pm}11.6$ sec at FRC, and $33.2{\pm}11.1$ sec at RV(TLC vs. FRC, p<0.05; FRC vs. RV, p<0.05). On rebreathing after $SaO_2$ decreased 2%, further decrement in $SaO_2$ was observed and it was significantly greater at RV($4.3{\pm}2.1%$) than at TLC($1.4{\pm}1.0%$)(p<0.05) or at FRC($1.9{\pm}1.4%$)(p<0.05). The time required for $SaO_2$ to return to the basal level after RB(Tr) at TLC was not significantly different from those at FRC or at RV. T2% had no significant correlation either with lung volumes or with BMR respectively. On the other hand, T2% had significant correlation with TLC/BMR(r=0.693, p<0.01) and FRC/BMR (r=0.615, p<0.025) but not with RV/BMR(r=0.227, p>0.05). The differences between maximal and minimal HR(${\Delta}HR$) during the BH-RB manuever were $27.5{\pm}9.2/min$ at TLC, $26.4{\pm}14.0/min$ at RV, and $19.1{\pm}6.0/min$ at FRC which was significantly smaller than those at TLC(p<0.05) or at RV(p<0.05). The mean difference of 5 p-p intervals before and after RB were $0.8{\pm}0.10$ sec and $0.72{\pm}0.09$ sec at TLC(p<0.001), $0.82{\pm}0.11$ sec and $0.73{\pm}0.09$ sec at FRC(p<0.025), and $0.77{\pm}0.09$ sec and $0.72{\pm}0.09$ sec at RV(p<0.05). Conclusion Healthy subjects showed arterial desaturation of various rates and extent during breath holding at different lung volumes. When breath held at lung volume greater than FRC, the rate of arterial desaturation significantly correlated with lung volume/basal metabolic rate, but when breath held at RV, the rate of arterial desaturation did not correlate linearly with RV/BMR. Sinus arrythmias occurred during breath holding and rebreathing manuever irrespective of the size of the lung volume at which breath holding started, and the amount of change was smallest when breath held at FRC and the change in vagal tone induced by alteration in respiratory movement might be the major responsible factor for the sinus arrythmia.