• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.316-326
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• 2014

Determination of the late marginal heading date (LMHD), which would allow estimation of the late marginal seeding date and the late marginal transplanting date, would help identification of potential double cropping areas and, as a result, establishment of cropping systems. The objective of this study was to determine the LMHD at 51 sites in Korea. For these sites, weather data were obtained from 1971 to 2000 and from 1981 to 2010, which represent past and current normal climate conditions, respectively. To examine crop productivity on the LMHD, climatic yield potential (CYP) was determined to represent the potential yield under a given climate condition. The LMHD was calculated using accumulated temperature for 40 days with threshold values of $760^{\circ}C$, $800^{\circ}C$, $840^{\circ}C$ and $880^{\circ}C$. The value of CYP on a given LMHD was determined using mean temperature and sunshine duration for 40 days from the LMHD. The value of CYP on the LMHD was divided by the maximum value of CYP (CYPmax) in a season to represent the relative yield on the LMHD compared with the potential yield in the season. Our results indicated that the LMHD was delayed at most sites under current normal conditions compared with past conditions. Spatial variation of the LMHD differed by the threshold temperature. Overall, the minimum value of CYP/CYPmax was 81.8% under all of given conditions. In most cases, the value of CYP/CYPmax was >90%, which suggested that yield could be comparable to the potential yield even though heading would have occurred on the LMHD. When the LMHD could be scheduled later without considerable reduction in yield, the late marginal transplanting date could also be delayed accordingly, which would facilitate doublecropping in many areas in Korea. Yield could be affected by sudden change of temperature during a grain filling period. Yet, CYP was calculated using mean temperature and sunshine duration for 40 days after heading. Thus, the value of CYP/CYPmax may not represent actual yield potential due to change of the LMHD, which suggested that further study would be merited to take into account the effect of weather events during grain filling periods on yield using crop growth model and field experiments.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.12
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• pp.656-661
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• 2016

Manufacturing membrane materials with high selectivity and permeability is quite desirable but practically not possible, since the permeability and selectivity are usually inversely proportional. From the viewpoint of reducing the cost of $CO_2$ capture, module performance is even more important than the performance of membrane materials itself, which is affected by the permeance of the membrane (P, stagecut) and selectivity (S). As a typical example, when the mixture with a composition of 13% $CO_2$ and 87% of $N_2$ is fed into the module with 10% stage cut and selectivity 5, in the 10 parts of the permeate, $CO_2$ represents 4.28 parts and $N_2$ represents 5.72 parts. In this case, the $CO_2$ concentration in the permeate is 42.8% and the recovery rate of $CO_2$ in this first separation appears as 4.28/13 = 32.9%. When permeance and selectivity are doubled, however, from 10% to 20% and from 5 to 10, respectively, the $CO_2$ concentration in the permeant becomes 64.5% and the recovery rate is 12.9/13 = 99.2%. Since in this case, most of the $CO_2$ is separated, this may be the ideal condition. For a given feed concentration, the $CO_2$ concentration in the separated gas decreases if permeance is larger than the threshold value for complete recovery at a given selectivity. Conversely, for a given permeance, increasing the selectivity over the threshold value does not improve the process further. For a given initial feed gas concentration, if permeance or selectivity is larger than that required for the complete separation of $CO_2$, the process becomes less efficient. From all these considerations, we can see that there exists an optimum design for a given set of conditions.

• Journal of Life Science
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• v.9 no.2
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• pp.136-145
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• 1999

The purpose of this study was to evaluate the effect of organic slovents and noise on hearing loss. We selected organic solvents exposed group of 32 cases, noise exposed group of 31 cases, both noise and solvent exposed group of 31 cases, and control group of 53 cases and studied the relation between exposure level of noise and organic solvents and degree of hearing loss. The results were as follows. The subjects under investigation were exposed to noise and organic solvents under threshold limit values and the amount of urinary hippuric acid excretion were also under biological exposure indices. In case of noise, both noise and organic solvents exposed group and noise exposed group were more exposed than organic solvents exposed group(p<0.05). When urinary hippuric acid excretion were concerned, both noise iud organic solvents exposed group and organic solvents exposed group showed higher values than noise exposed group(p<0.05). In comparison of mean auditory threshold values by frequency, on the air conduction test, both noise and organic solvents exposed group showed significantly higher hearing loss than noise exposed group in 500Hz of right ear, 500 and 2000Hz of left ear(p<0.05). Forty-three cases among 147 subjects were regarded as hearing loss group and average age(42.6years) of hearing loss group was higher than normal groups average age of 38.0 years. Urinary hippuric acid excretions of hearing loss group were significantly higher than normal group(p<0.05). Thirty-eight percent(12cases) of noise exposed group, 40.6 $\%$(13cases) of organic solvents exposed group, 51.6 $\%$(16cases) of both noise and organic solvents exposed group, and 3.8 $\%$(2cases) of unexposed group were regarded as hearing losers. Exposed groups showed higher incidence of hearing loss than unexposed group but there were no significant differences among the exposed groups. The variables showing significant correlation with hearing loss were age and the amount of hippuric acid in urinary excretion. When age were adjusted for the purpose of seeing the effects of hearing losses due to organic solvent, urinary excretion of hippuric acids was the only variable with significant correlation with hearing loss (p<0.05). When odds ratio to hearing loss between control and exposed groups was considered, noise exposed group showed 6.1 times (95 $\%$ CI: 3.3-8.7), organic solvents exposed group showed 7.4 times (95 $\%$ CI: 3.5-14.6) and both noise and organic solvents exposed group showed 17.2 times(95% CI: 5.6-31.8) higher values than unexposed group(p<0.01). Above results suggest that health screening test of hearing loss is also needed in organic solvents exposed workers.

• The Korean Journal of Pharmacology
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• v.30 no.1
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• pp.29-37
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• 1994

Inhibition of the nociceptive Tail Flick Reflex (TFR) was observed with electrical stimulation of the locus coeruleus/subcoeruleus (LC/SC) in the male Sprague - Dawley rats under light anesthesia, and the involved neurotransmitter (s) were characterized. Electrical stimulation of LC/SC induced the analgesia with the stimulation threshold (intensity of the current, given for 100 usec and in 100 Hz frequency, which caused the TF latency longer than 6.5 sec) around 55 uA. Intrathecal administrations of ${\alpha}_2$ antagonist, yohimbine (30 ug) or opioid antagonist, naloxone (20 ug) increased the stimulation threshold by 147% and 123% respectively (from 55 uA to 135 uA,9 and from 54 uA to 123 uA;P0.01, n=5, each). The basal TF latency without stimulation (3.1 sec) was reduced by the antagonists (to 2.5 sec by yohimbine, p<0.05, n=5; to 2.6 sec by naloxone, p<0.1, n=5), vehicle only did not show any effect. Noradrenaline(NA) in the spinal cord superfusates measured with HPLC was increased by the LC/SC stimulation, from 4.18 ng/ml before to 7.74 ng/ml after stimulation (P<0.05, n=10). The result suggest that analgesia induced by LC/SC stimulation is mediated, at least in part, by the noradrenergic system in which ${\alpha}_2$ receptor is involved, as well as the opioid system.

• Journal of Oral Medicine and Pain
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• v.36 no.4
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• pp.225-234
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• 2011

Tobacco smoking is a major risk factor of systemic health and also impairs oral health, which is related to development of oral cancers, periodontitis, delayed wound healing, tooth loss, failure of implant, etc. Aside from smoking, many other risk factors can be related to oral health and long-term effects of smoking on salivary flow and taste threshold are still in controversy. Authors considered dental students to be an appropriate group with good oral hygiene for a long-term study to reveal effects of smoking on oral health. This study was performed to compare smoking patterns and current oral health conditions between smokers and nonsmokers in dental students prior to long-term evaluation. 192 volunteers (85.7%) of 224 male dental students in Dankook University were evaluated through questionnaires and clinical examination in 2010. Questionnaires included smoking pattern, alcohol use, nicotine dependence, preventive care, psychological profile and clinical examinations comprised assessment of teeth or periodontal status, nicotine pigmentation, salivary flow, electrical taste thresholds and halitosis. From the study, (current) smokers were older, and drank more frequently with more alcohol intake compared to former smokers and nonsmokers(p<0.05). There was no significant difference among them in salivary flow rate, halitosis and electrical taste threshold. However, there was significant difference in DMFT rate, periodontal treatment need, nicotinic pigmentation between smokers and nonsmokers(p<0.05), irrespective of their levels of preventive care. The smokers in this study, who are young dental students with relatively shorter duration of smoking, less use of cigarettes and low level of nicotine dependence, did not reveal significant impairment of oral health. However, their oral health was found to be relatively impaired compared to nonsmokers', which suggests negative effect of smoking on the oral health and a need of smoking cessation.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.265-279
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• 1996

Damage produced by radiation elicits a complex response in mammalian cells, including growth rate changes and the induction of a variety of genes associated with growth control and apoptosis. At doses of 10,000 cGy or greater, the exposed individual was killed in a matter of minutes to a couple of days, with symptoms consistent with pathology of the central nervous system(CNS) including degenerative changes. The nature of the damage in irradiated cells underlies the unique hazards of ionizing radiation. Radiation injury to CNS is a rare event in clinical medicine, but it is catastrophic for the patient in whom it occurs. The incidence of cerebral necrosis has been reported as high as 16% for doses greater than 6,000 cGy. In this study, the effect of radiation on brain tissue was studied in vivo. Jun and p53 genes in the rat brain were induced by whole body irradiation of rat with 600Co in doses between 1 Gy and 100 Gy and analyzed for expression of jun and p53 genes at the postirradiation time up to 6 hours. Northern analyses were done using 1.8 Kb & 0.8 Kb-pGEM-2-JUN/Eco RI/Pst I fragments, 2.0 Kb-php53B/Bam HI fragment and ,1.1 Kb-pBluescript SK--ACTIN/Eco RI fragment as the digoxigenin or [${\alpha}^{32}P$] dCTPlabeled probes for Jun, p53 and ${\beta}$-actin genes, respectively. Jun gene seemed to be expressed near the threshold levels in 1 hour after irradiation of $^{60}$Co in dose less than 1 Gy and was expressed in maximum at 1 hour after irradiation of $^{60}$Co in dose of 30 Gy. Jun was expressed increasingly with time until 5 or 6 hours after irradiation of $^{60}$Co in doses of 1 Gy and 10 Gy. After irradiation of $^{60}$Co in dose between 20 Gr and 100 Gy, the expression of Jun was however increased to peak in 2 hours and decreased thereafter. p53 gene in this study also seemed to be expressed near the threshold levels in 1 hour after irradiation of $^{60}$Co in dose less than 1 Gy and was expressed in maximum at 6 hours after irradiation of $^{60}$Co in dose of 1 Gy, p53 was expressed increasingly with time until 5 or 6 hours after irradiation of $^{60}$Co in dose between 1 Gy and 40 Gy. After irradiation of $^{60}$Co in doses of 50 Gy and 100 Gy, the expression of p53 was however increased to peak in 2 hours and decreased thereafter. The expression of Jun and p53 genes was not correlative in the brain tissue from rats. It seemed to be very important for the establishment of the optimum conditions for the animal studies relevant to the responses of genes inducible on DNA damage to ionizing radiation in mammalian cells. But there are many limitations to the animal studies such as the ununiform patterns of gene expression from the tissue because of its complex compositions. It is necessary to overcome the limitations for development of in situ Northern analysis.

• Journal of Preventive Medicine and Public Health
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• v.36 no.2
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• pp.137-146
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• 2003

Objectives : Impaired hearing is a prevalent occupational hazard, not only in industry, but also in the armed forces. In military life, noise has unusual characteristics, and constitutes a serious hazard to hearing. The aim of this study was to analyze the hearing threshold data in order to compare the hearing loss among shipyard workers, representing different workers, and a military service background. Methods : A cross-sectional audiological survey, combined with a questionnaire study, was conducted on a stratified random sample of 440 shipyard workers, with long-term exposure to noise. The employees were divided into four groups, according to their working and military service backgrounds, in relation to their exposure to noise. Results : As expected, the working and military noise exposure group (Group I) had significantly poorer hearing than the other groups. The high frequencies (2-8 kHz) showed the greatest difference in terms of poorer fearing in both ears. The prevalence of noise-induced hearing loss (NIHL) was highest in Group I. A logistic regression analysis was applied to determine the dependence of the NIHL in relation to age, smoking, drinking, working duration, ear protection, past history of ear diseases, and working and military sonics backgrounds, on the noise exposure The important factors found to be related to the NIHL, in relation to noise exposure were: age, work duration, and working and military service backgrounds. The adjusted odds ratio estimates for NIML in the right ear were 4.5 times greater (95% CI 1.7-11.6) for the military noise exposed group, and 7.9 times greater (95% CI 2.0-31.3) for the working noise exposed group than in the controls. The hearing thresholds at the pure-tone average and 4 kHz were significantly increased with age and work duration with both the working and military service backgrounds. Conclusions : From these results, specific preventive programs were planned, which should be assessed by epidemiological surveillance of the military noise exposed population.

• Korean journal of applied entomology
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• v.44 no.4 s.141
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• pp.325-330
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• 2005

This study was conducted to determine the effect of temperatures on the egg and nymphal development, adult longevity and oviposition of bean bug, Riptortus clavatus Thunberg, using Saealkong seed as food sources in fibrous nylon-tube at four different temperatures (20, 24, 28 and $32^{\circ}C$). Hatchability showed the highest value of 100% at $28^{\circ}C$ and decreased with increasing temperature. Egg duration ranged from 7 days at $32^{\circ}$ to 16.7 days at $20^{\circ}C$. Instar duration was longer with increasing instar stage. Nymphal duration was 38 days at $20^{\circ}C$, 30 days at $24^{\circ}C$, 23 days at $28^{\circ}C$, and 18 days at $32^{\circ}C$ Emergence rates to adult were 16, 41, 72 and 68% at 20, 24, 28 and $32^{\circ}C$, respectively. Female adult longelity ranged from a minimum 20 days at $20^{\circ}C$ to a maximum 63 days at $28^{\circ}C$, while the longevity of male ranged from 19 days at $20^{\circ}C$ to 60 days at $28^{\circ}C$. Preoviposition duration was shorter with increasing temperature and ranged from 11 days at $20^{\circ}C$ to 5 days at $32^{\circ}C$. Total number of eggs laid per female ranged from a minimum 21 eggs at $20^{\circ}C$ to a maximum 67 eggs at $28^{\circ}C$. Consequently, the estimated lower threshold tempeatures of each developmental stage were $10.3^{\circ}C$ for egg, and 9.3, 12.7, 10.0, 11.0 and 8.7 for the 1st, 2nd, 3rd, 4th and 5th instar, respectively.

• Journal of Oral Medicine and Pain
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• v.32 no.2
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• pp.177-185
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• 2007

Iatrogenic injury following dental treatments and the use of local anesthetics may cause taste disorders. The aims of this study were to investigate quantitative and qualitative changes of taste due to unilateral inferior alveolar nerve block anesthesia and further to evaluate potential effects on taste function related to anesthesia or hypoesthesia of inferior alveolar nerve, possibly occurring after dental procedure. 30 healthy volunteers in their twenties participated in this study (male to female = 1:1, mean age of $24.0{\pm}1.8$ years). Each subject received inferior alveolar nerve block anesthesia on his or her right side with 2% lidocaine HCl containing 1:100,000 epinephrine. Before and after anesthesia, electrogustometric test and chemical localized test for salty, sweet, sour and bitter tastes were performed on the eight sites in the oral cavity; right and left anterior and lateral tongue and circumvallate papilla of the tongue and soft palate. Unilateral inferior alveolar nerve anesthesia produced elevation of electrical taste threshold and reduction of intensity ratings for all 4 tastes (salty, sweet, sour and bitter) over anterior and lateral tongue and circumvallate papilla on the ipsilateral side (p<0.05). Contralateral sides exhibited decreased intensity ratings for salty and sweet taste (p<0.05) on anterior and lateral tongue while there was no significant difference in electrogustometric testing. Based on the results of this study, it is assumed that unilateral local anesthesia on inferior alveolar nerve can affect chorda tympani and glossopharyngeal nerves on the same side, leading to taste deficits. Taste intensity on the contralateral side may, in part, be deteriorated as well.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.635-645
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• 2019

Non-specific chronic neck pain (CNP) is a prevalent disorder and often accompany with pain, fatigue, reduced range of motion (ROM), and hand function. Although various types of drug are commonly used to manage the symptoms following CNP, there is a need for therapeutic exercise and alternative medicine interventions that have few side effects or are easy to apply. Present study investigated the effects of salt pack and neck exercise for life care of the elderly with non-specific CNP. Sixteen patients with non-specific CNP were recruited and randomly assigned into two groups: the intervention group (n=8) or the control group (n=8). All patients performed neck self-exercise for 30 min/day, 5 times a week for 1 week. And the subjects in the intervention group additionally received salt hot pack for 20 min per session. Visual analogue scale (VAS) and pain pressure threshold (PPT) using algometer were used to assess pain intensity (primary outcome). ROM of shoulder joint and grip strength were measured to test shoulder and hand function (secondary outcome). There were significant improvements in the intervention group (p<.05), while the subjects in the control group did not show a significant change after intervention (p>.05). Also, the intervention group show significant differences in VAS and PPT compared to the control group (p<.05). Thus, our results demonstrated that salt pack and neck exercise have a positive effect for life care in elderly patients with non-specific CNP.