• Tuberculosis and Respiratory Diseases
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• v.60 no.4
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• pp.451-463
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• 2006

Background : Reactive oxygen species (ROS) take center stage as executers in ventilator-induced lung injury (VILI). The protein with DNA-damage scanning activity, poly (ADP-ribose) polymerase-1 (PARP1), signals DNA rupture and participates in base-excision repair. Paradoxically,overactivation of PARP1 in response to massive genotoxic injury such as ROS can induce cell death through ${\beta}$ -nicotinamide adenine dinucleotide ($NAD^+$) depletion, resulting in inflammation. The purpose of this study is to investigate the role of PARP1 and the effect of its inhibitor in VILI. Methods : Forty-eight male C57BL/6 mice were divided into sham, lung protective ventilation(LPV), VILI, and PARP1 inhibitor (PJ34)+VILI (PJ34+VILI) groups. Mechanical ventilator setting for the LPV group was $PIP\;15cmH_2O$ + $PEEP\;3cmH_2O$ + RR 90/min + 2 hours. The VILI and PJ34+VILI groups were ventilated on a setting of $PIP\;40cmH_2O$ + $PEEP\;0cmH_2O$ + RR 90/min + 2 hours. As a PARP1 inhibitor for the PJ34+VILI group, 20 mg/Kg of PJ34 was treated intraperitoneally 2 hours before mechanical ventilation. Wet-to-dry weight ratio and acute lung injury (ALI) score were measured to determine the degree of VILI. PARP1 activity was evaluated by using an immunohistochemical method utilizing biotinylated NAD. Myeloperoxidase (MPO) activity and the concentration of inflammatory cytokines such as tumor necrosis factor $(TNF)-{\alpha}$, interleukin $(IL)-1{\beta}$, and IL-6 were measured in bronchoalveolar lavage fluid (BALF). Results : In the PJ34+VILI group, PJ34 pretreatment significantly reduced the degree of lung injury, compared with the VILI group (p<0.05). The number of cells expressing PARP1 activity was significantly increased in the VILI group, but significantly decreased in the PJ34+VILI group (p=0.001). In BALF, MPO activity, $TNF-{\alpha}$, $IL-1{\beta}$, and IL-6 were also significantly lower in the PJ34+VILI group (all, p<0.05). Conclusion : PARP1 overactivation plays a major role in the mechanism of VILI. PARP1 inhibitor prevents VILI, and decreases MPO activity and inflammatory cytokines.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.378-385
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• 2017

In this study, we evaluated the changes of fruit quality indices during fruit development and ripening in Korean new pear cultivar 'Changjo', developed from a cross between 'Tama' and '81-1-27' ('Danbae' ${\times}$ 'Okusankichi') in 1995 and named in 2009, to determine appropriate harvest time and to enhance the market quality and broaden the cultivation area. The fruits of 'Changjo' pears harvested from 132 days after full bloom (DAFB) to 160 DAFB. Fruit growth and quality indices were monitored at 1 week interval by measuring fruit weight, length, diameter, firmness, and taste related quality indices. The calculated fruit fresh weight increased continuously with fruit development and reached to an average of 594g on Sep. 20 (160 DAFB). The ratio of length to diameter declines as fruit maturation progress, resulting in 0.898 for ripe fruit stage as a round oblate shape. Flesh firmness of 'Changjo' pears showed over 30N until 153 DAFB and then decreased abruptly with fruit ripening, reaching a final level of about 26.44N on 160 DAFB. Starch content of fruit sap was also decreased abruptly after 146 DAFB which decreased almost half of the fruits harvested at 139 DAFB. In parallel with the decrease of flesh firmness, ethanol insoluble solids (EIS) content decreased sharply with fruit ripens, only 50% of EIS was detected on the fruits harvested on 160 DAFB when compared to that of the fruits harvested on 139 DAFB (Aug. 30). The maximum value of soluble solids contents was observed in the fruits harvested on 153 DAFB, resulting in $14.2^{\circ}Brix$. The changes of skin color difference $a^*$ which means loss of green color occurred only after 139 DAFB, coincide with the decrease of SPAD value of the fruit skin. The sugars of the 80% ethanol soluble fraction consisted mainly of fructose, sorbitol, glucose and sucrose, also increased during maturation and ripening. Fructose and sucrose contents were larger than those of glucose and sorbitol in flesh tissues. These results were explained that stored starch is converted to soluble sugars during fruit maturation, mainly in fructose and sucrose increasing the sweetness of this cultivar. Total polyphenols were increased up to middle of fruit maturation (146 DAFB) and then decreased continuously until the end of fruit maturation. Consequently, our results suggested that the commercial harvest time of 'Changjo' pears should not be passed 153 DAFB and late harvest of this cultivar would not good for quality maintenance during shelf-life. As a result of the post-harvest low-temperature acclimation experiment during the short-term transportation period, fruits harvested at 146 DAFB tended to maintain higher firmness after 14 days of simulated marketing at $25^{\circ}C$ compared to fruits harvested at 153 DAFB regardless of temperature set. And, the slower the rate of decrease to the final transport temperature of $5^{\circ}C$, the higher the incidence of internal browning and ethylene production. Therefore, in order to suppress the physiological disorder and to maintain the fruit quality when exporting to Southeast Asia in the 'Chanjo' pears, it is desirable to lower the temperature of the fruits within a short time after harvest and to set the harvest time before 146 days after full bloom.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.162-166
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• 2012

Purpose : Vitamin $B_{12}$ and Folate are for anemia work-up which is well known for its sensitivity of light; the screening manual also specifies to be careful with light conditions. According to this, our laboratory minimized the exposure of light when inspecting the Vitamin $B_{12}$ and Folate, but the exposure cannot be wholly blocked due to other various factors such as when conducting specimen segregation. Thus, this inspection is to identify to what extent light can influence and whether the exclusion of light is mandatory during the Vitamin $B_{12}$/Folate test. Materials and Methods : We have conducted two experiments of identifying the extent of light's influence when conducting the Vitamin $B_{12}$/Folate test and also when specimens are under preservation. These experiments were progressed with various concentrations of patients' specimens which were requested to our hospital in March 2012. The first experiment is to verify the results on Vitamin $B_{12}$/Folate dependent on light exposure during the experiment. In the process, we have compared the results of light exposure/exclusion during the incubation process after the reagent division. The second experiment is about the impact of light exposure on the results on Vitamin $B_{12}$/Folate during the preservation. For 1, 2, 7 days the light on the specimen were wholly blocked and were preserved under $-15^{\circ}C$ temperature refrigeration. Then, we compared the results of light-excluded specimen and the exposed one. Results : When conducting first experiment, there were no noticeable changes in the Standard and specimen's cpm, but for Vitamin $B_{12}$, the average result of specimen exposed to light increased 7.8% compare to that of excluded one's. Furthermore, in the significant level 0.05, the significance probability or the p-value was 0.251 which means it has no impact. For Folate, the result being exposed to light decreased 5.4%, the significance probability was 0.033 which means it has little impact. For the second preservation, the result was dependent on the light exposure. The first day of preservation of Vitamin $B_{12}$, the clinical material exposed to light was 11.6%, second day clinical material exposed to light was 10.8%, seventh day clinical material exposed to light increased 3.8%, the significance probability of the $1^{st}$, $2^{nd}$, $7^{th}$ day is 0.372, 0.033, 0.144 respectively, and which indicates that the $1^{st}$ and $7^{th}$ day seems to have no impact. For Folate's case, the clinical material exposed to light has increased 1.4% but hardly had impact, $2^{nd}$ day clinical material being exposed to light was 6.1%, $7^{Th}$ day clinical material being exposed to light decreased 5.2%. The significance probability of Folate on the $1^{st}$, $2^{nd}$, $7^{th}$ day is 0.378, 0.037, 0.217 respectively, and the $1^{st}$ day and the $7^{th}$ day seems to have no impact. Conclusion : After scrutinizing the impact of light exposure/exclusion, Vitamin $B_{12}$ has no impact, while Folate seems to have no noticeable influence but light exclusion is recommended due to its significance probability of 0.033 when conducting experiment. During the preservation, the $2^{nd}$ day result depend on the light exclusion seems to have impact or influence. However, to consider the complication of the experimental process, the experiment including technical errors is predictable. Hence, it is likely to have no impact of light. Nevertheless, it is recommendable to exclude the light during the long preservation as per the significance probability (p-value) of $1^{st}$ and $7^{th}$ day has been diminished.

• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.169-196
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• 2017

The fourth industrial revolution represents a revolutionary change in the business environment and its ecosystem, which is a fusion of Information Technology (IT) and other industries. In line with these recent changes, the Ministry of Employment and Labor of South Korea announced 'the Fourth Industrial Revolution Leader Training Program,' which includes five key support areas such as (1) smart manufacturing, (2) Internet of Things (IoT), (3) big data including Artificial Intelligence (AI), (4) information security, and (5) bio innovation. Based on this program, we can get a glimpse of the South Korean government's efforts and willingness to emit leading human resource with advanced IT knowledge in various fusion technology-related and newly emerging industries. On the other hand, in order to nurture excellent IT manpower in preparation for the fourth industrial revolution, the role of educational institutions capable of providing high quality IT education services is most of importance. However, these days, most IT educational institutions have had difficulties in providing customized IT education services that meet the needs of consumers (i.e., learners), without breaking away from the traditional framework of providing supplier-oriented education services. From previous studies, it has been found that the provision of customized education services centered on learners leads to high satisfaction of learners, and that higher satisfaction increases not only task performance and the possibility of business application but also learners' recommendation intention. However, since research has not yet been conducted in a comprehensive way that consider both antecedent and consequent factors of the learner's satisfaction, more empirical research on this is highly desirable. With the advent of the fourth industrial revolution, a rising interest in various convergence technologies utilizing information technology (IT) has brought with the growing realization of the important role played by IT-related education services. However, research on the role of IT education service quality in the context of IT education is relatively scarce in spite of the fact that research on general education service quality and satisfaction has been actively conducted in various contexts. In this study, therefore, the five dimensions of IT education service quality (i.e., tangibles, reliability, responsiveness, assurance, and empathy) are derived from the context of IT education, based on the SERVPERF model and related previous studies. In addition, the effects of these detailed IT education service quality factors on learners' educational satisfaction and their work application/recommendation intentions are examined. Furthermore, the moderating roles of learner position (i.e., practitioner group vs. manager group) and participation motivation (i.e., voluntary participation vs. involuntary participation) in relationships between IT education service quality factors and learners' educational satisfaction, work application intention, and recommendation intention are also investigated. In an analysis using the structural equation model (SEM) technique based on a questionnaire given to 203 participants of IT education programs in an 'M' IT educational institution in Seoul, South Korea, tangibles, reliability, and assurance were found to have a significant effect on educational satisfaction. This educational satisfaction was found to have a significant effect on both work application intention and recommendation intention. Moreover, it was discovered that learner position and participation motivation have a partial moderating impact on the relationship between IT education service quality factors and educational satisfaction. This study holds academic implications in that it is one of the first studies to apply the SERVPERF model (rather than the SERVQUAL model, which has been widely adopted by prior studies) is to demonstrate the influence of IT education service quality on learners' educational satisfaction, work application intention, and recommendation intention in an IT education environment. The results of this study are expected to provide practical guidance for IT education service providers who wish to enhance learners' educational satisfaction and service management efficiency.

• Journal of Yeungnam Medical Science
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• v.17 no.1
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• pp.21-30
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• 2000

Background: The purpose of the present study was to investigate the effect of exercise on the activities of antioxidant enzymes, super oxide dismutase(SOD), glutathione peroxidase(GPX) and catalase(CAT) of skeletal muscle(gastrocnemius) and liver in streptozotocin(STZ) induced diabetic rats. The malondialdehyde(MDA) concentration was also measured as an index of lipid poroxidation of tho tissues by exercise-induced oxidative stresses in diabetic rats. Material and Methods: Male Sprague-Dawley rats were randomly divided into control and STZ-induced diabetic rats. The STZ in citrate buffer solution was injected twice at S days intervals intraperitoneally(50, 70 mg/kg respectively). On the 28th day after the first STZ injection, the diabetic animals were randomly divided into pre- and post-exercise groups, The exercise was introduced to the rats of post-exercise group by treadmill running until exhaution with moderate intensity ($V_{O2max}$: 50-70%) of exercise. The duration of average running time was 2 hours and 19 minutes. Results: The blood glucose concentration was increased(p<0.001) and plasma insulin concentration was decreased(p<0.001) in the diabetic rats. The glycogen concentration in the muscle and liver was decreased by exhaustive exercise in the diabetic rats(p<0.001), In the skeletal muscle, the activities of GPX was increased(p<0.05) and the activities of SOD and CAT were not changed in the diabetic rats compare to those of the control rats. The activities of GPX was not changed by exercise but the activities of SOD(p<0.01) and CAT(p<0.01) were decreased by exercise in the diabetic rats, The concentration of MDA was not changed by exercise in diabetic rats, and the values of pre-exercise and post-exercise diabetic rats were not different from the value those of control rats, In the liver, the activities of SOD was decreased(p<0.01), and the activities of GPX and CAT were not changed in diabetic rats compared to the values of control rats, The activities of SOD, GPX and CAT were not changed by exercise in diabetic rats but the activity of SOD seemed to decrease slightly, The MDA concentration was increased in the diabetic rats compared to the values of control rats(p<0.001), but there was no change of MDA concentration by exercise in diabetic rats, Conclusions: In summary, exhaustive physical exercise did not seem to impose oxidative stress on the skeletal muscle because of due to oxygen free radicals, regardless of the decrease in SOD and CAT in the diabetic rats, In liver tissue, the tissue damage by oxidative stress was observed in diabetic rats but the additional tissue damage by exhaustive physical exercise was not observed.

• Journal of Distribution Research
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• v.16 no.1
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• pp.95-115
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• 2011

Food service is the major part of franchise business in Korea, accounting for 69.9% of the brands in the market. As the food service industry becomes mature, many franchisees have struggled to survive in the market. In general, consumers have higher levels of expectation toward service quality of franchised outlets compared that of (non-franchised) independent ones. They also tend to believe that franchisees deliver standardized service at the uniform food price, regardless of their locations. Such beliefs seem to be important reasons that consumers prefer franchised outlets to independent ones. Nevertheless, few studies examined the impact of qualify features of franchisees on customer satisfaction so far. To this end, this study examined the characteristics of various quality features of franchisees in the food service industry, regarding their relationship with customer satisfaction and dissatisfaction. The quality perception of heavy-users was also compared with that of light-users in order to find insights for developing differentiated marketing strategy for the two segments. Customer satisfaction has been understood as a one-dimensional construct while there are recent studies that insist two-dimensional nature of the construct. In this regard, Kano et al. (1984) suggested to categorize quality features of a product or service into five types, based on their relation to customer satisfaction and dissatisfaction: Must-be quality, Attractive quality, One-dimensional quality, Indifferent quality, and Reverse quality. According to the Kano model, customers are more dissatisfied when Must-be quality(M) are not fulfilled, but their satisfaction does not arise above neutral no matter how fully the quality fulfilled. In comparison, customers are more satisfied with a full provision of Attactive quality(A) but manage to accept its dysfunction. One-dimensional quality(O) results in satisfaction when fulfilled and dissatisfaction when not fulfilled. For Indifferent quality(I), its presence or absence influences neither customer satisfaction nor dissatisfaction. Lastly, Reverse quality(R) refers to the features whose high degree of achievement results in customer dissatisfaction rather than satisfaction. Meanwhile, the basic guidelines of the Kano model have a limitation in that the quality type of each feature is simply determined by calculating the mode statistics. In order to overcome such limitation, the relative importance of each feature on customer satisfaction (Better value; b) and dissatisfaction (Worse value; w) were calculated following the formulas below (Timko, 1993). The Better value indicates how much customer satisfaction is increased by providing the quality feature in question. In contrast, the Worse value indicates how much customer dissatisfaction is decreased by providing the quality feature. Better = (A + O)/(A+O+M+I) Worse = (O+M)/(A+O+M+I)(-1) An on-line survey was performed in order to understand the nature of quality features of franchisees in the food service industry by applying the Kano Model. A total of twenty quality features (refer to the Table 2) were identified as the result of literature review in franchise business and a pre-test with fifty college students in Seoul. The potential respondents of our main survey was limited to the customers who have visited more than two restaurants/stores of the same franchise brand. Survey invitation e-mails were sent out to the panels of a market research company and a total of 257 responses were used for analysis. Following the guidelines of Kano model, each of the twenty quality features was classified into one of the five types based on customers' responses to a set of questions: "(1) how do you feel if the following quality feature is fulfilled in the franchise restaurant that you visit," and "(2) how do you feel if the following quality feature is not fulfilled in the franchise restaurant that you visit." The analyses revealed that customers' dissatisfaction with franchisees is commonly associated with the poor level of cleanliness of the store (w=-0.872), kindness of the staffs(w=-0.890), conveniences such as parking lot and restroom(w=-0.669), and expertise of the staffs(w=-0.492). Such quality features were categorized as Must-be quality in this study. While standardization or uniformity across franchisees has been emphasized in franchise business, this study found that consumers are interested only in uniformity of price across franchisees(w=-0.608), but not interested in standardizations of menu items, interior designs, customer service procedures, and food tastes. Customers appeared to be more satisfied when the franchise brand has promotional events such as giveaways(b=0.767), good accessibility(b=0.699), customer loyalty programs(b=0.659), award winning history(b=0.641), and outlets in the overseas market(b=0.506). The results are summarized in a matrix form in Table 1. Better(b) and Worse(w) index indicate relative importance of each quality feature on customer satisfaction and dissatisfaction, respectively. Meanwhile, there were differences in perceiving the quality features between light users and heavy users of any specific franchise brand in the food service industry. Expertise of the staffs was labeled as Must-be quality for heavy users but Indifferent quality for light users. Light users seemed indifferent to overseas expansion of the brand and offering new menu items on a regular basis, while heavy users appeared to perceive them as Attractive quality. Such difference may come from their different levels of involvement when they eat out. The results are shown in Table 2. The findings of this study help practitioners understand the quality features they need to focus on to strengthen the competitive power in the food service market. Above all, removing the factors that cause customer dissatisfaction seems to be the most critical for franchisees. To retain loyal customers of the franchise brand, it is also recommended for franchisor to invest resources in the development of new menu items as well as training programs for the staffs. Lastly, if resources allow, promotional events, loyalty programs, overseas expansion, award-winning history can be considered as tools for attracting more customers to the business.

• Korean Journal of Biological Psychiatry
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• v.7 no.1
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• pp.85-98
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• 2000

Objective : There are four possible explanations for the sexual dysfunction of schizophrenics. The first is the possibility of a real structural aspect. The second possibility is that sexual function changes secondary to the illness. The third possibility is that there are medical and sociocultural barriers to sexual expression for chronic schizophrenics. The fourth possibility is that sexual dysfunction due to antipsychotic medication. However, we didn't know the precise cause of sexual dysfunction in schizophrenics. Therefore, the purpose of this study was to explore the mechanism of illness itself and antipsychotics on sexual dysfunction in male schizophrenics. Methods : The serum prolactin(PRL), testosterone(TST), and the plasma serotonin(5-HT) concentrations were measured by radioimmunoassay and high performance liquid chromatography method for 100 healthy male schizophrenics according to the DSM-IV. Concomitantly, the severity of psychotic symptoms using Clinical Global Impression(CGI), Brief Psychiatric Rating Scale(BPRS), Positive and Negative Syndrome Scale(PANSS), and the severity of side effects for antipsychotics using Extrapyramidal Side Effects Scale(EPSE), Anticholinergic Side Effects Scale(ACSE), the cognitive function using PANSS-Cognitive Function(PANSS-CF), Mini Mental State Exam-Korean(MMSE-K), and the sexual dysfunction using Sexual Functioning Questionnaire(SFQ), Questionnaire for Sexual Dysfunction in Men were assessed. The PRL, TST, and 5-HT levels of 50 healthy male controls who had no medical, neurological, and psychiatric illnesses were evaluated. The sexual function using SFQ(items FGa, FNa) were also assessed. Furthermore, the correlation with age, education, religion, economic status, age at onset, duration of illnesses, duration of admission, levels of PRL, TST, 5-HT, antipsychotic dosages, potency, benztropine, total duration of medication, EPSE, ACSE, CGI, BPRS, PANSS, PANSS-CF, MMSE-K and sexual dysfunctions were identified in male schizophrenics. Results : 1) The frequencies of sexual dysfunctions for schizophrenics(80%) were significantly(p<0.001) higher than those for controls(42%). The sexual dysfunctions according to sexual response cycle were 'low sexual desire' 76%, 'impairment of achieving erection' 75%, 'impairment of maintaining erection' 75%, 'impairment of obtaining orgasm' 32%, 'impairment in the quality of orgasm' 61%, 'impairment in quantity of ejaculate' 44%, 'premature ejaculation' 15%, and 'delayed ejaculation' 50%. 2) The PRL, 5-HT levels of schizophrenics($28.5{\pm}20.6ng/ml$, $298.5{\pm}89.1ng/ml$) were significantly(p<0.001) higher than those of controls($10{\pm}5.6ng/ml$, $169.2{\pm}37.8ng/ml$), while the TST levels of schizophrenics($4.3{\pm}1.5ng/ml$) and controls($4.5{\pm}1.2ng/ml$) were not significantly different. The sexual dysfunctions of schizophrenics who had abnormal 5-HT levels($4.7{\pm}1.3$ scores) were significantly(p<0.05) higher than those of who had normal 5-HT levels($3.8{\pm}1.6$ scores) on item D7. 3) The sexual dysfunctions of unmarried schizophrenics were significantly(p<0.01 : p<0.05) higher than those of married schizophrenics($6.1{\pm}2.8$ scores, $4.7{\pm}1.3$ scores on item FGa : ${\beta}$=-0.211 on item FNa). The sexual dysfunctions were positively correlated with the rise of 5-HT levels(r=0.209, p<0.05 on item D4 and r=0.241, p<0.05 on item D7), the higher age at onset(r=0.275, p<0.01 on item FNa : r=-0.202, p<0.05 on item FDa), the longer duration of illnesses(r=0.237, p<0.05 on item D6), the longer duration of admission(r=0.234, p<0.05 on item D4 : r=0.328, p<0.05 on item D6), the longer total duration of medication(r=0.237, p<0.05 on item D6). However, age, education, religion, economic status, PRL, TST levels, antipsychotics dosage, potency, benztropine, ACSE, CGI, BPRS, PANSS, PANSS-CF, MMSE-K scores were not correlated with increased sexual dysfunctions. Conclusions : Male schizophrenics have significantly more sexual dysfunction to compare with controls. The higher frequencies of sexual dysfunctions were low sexual desire and erectile disorder. The unmarried, higher age at onset, and longer duration of diseases were positively correlated with increased sexual dysfunctions. Also high 5-HT levels were positively correlated with increased sexual dysfunctions. This means that studies of plasma 5-HT levels, albeit questionable indicators of central 5-HT function, offer some additional support for the association of sexual dysfunction with excess 5-HT activity as primary pathology of schizophrenia. Our findings suggest that excess 5-HT activity seems to affect the patient's sexual function.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1519-1527
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• 2002

Purpose : Although influenza virus is one of the most important causes of acute respiratory tract infections(ARTIs) in children, virus isolation is not popular and there are only a few clinical studies on influenza in Korea. We evaluated the epidemiologic and clinical features of ARTIs by influenza virus in children. Methods : From February 1995 to August 2001, nasopharyngeal aspirations were obtained and cultured for the isolation of influenza virus in children admitted with ARTIs. The medical records of patients with influenza virus infection were reviewed retrospectively. Results : Respiratory viruses were isolated in 997(22.0%) out of 4,533 patients examined, and influenza virus was isolated in 164 cases(3.6%). Influenza virus was isolated year after year mainly from December to April of next year. The ratio of male and female was 1.9 : 1 with a median age of 15 months. The most common clinical diagnosis of influenza virus infection was pneumonia, and fever and cough developed in most patients. There was no difference between influenza A and B infection in clinical diagnoses and symptoms. All patients recovered without receiving antiviral treatment except for one patient diagnosed with pneumonia who had underlying disease of Down syndrome with ventricular septal defect. Conclusion : ARTIs caused by influenza virus developed every winter and spring during the period of study. Because fatal complication can develop in the high risk group, prevention, early diagnosis and proper management of influenza should be emphasized.

• The Korean Journal of Physiology
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• v.18 no.2
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• pp.151-162
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• 1984

The mechanism of the contractile response of longitudial muscle of rabbit ileum to substance P (SP) has been investigated. The contractions in rabbit ileum under various conditions were recorded isometrically The following results were obtained. 1) The contractions by SP increased according to concentrations. SP·induced contraction was not sustained but faded rapidly at $10^{-7}M$. The response to the commutative addition of SP was decreased in comparison to the response to separate administration of each concentration . 2) The response to $10^{-8}M$ SP after 5 min application cf $10^{-7}M$ SP was increased with increasing the time interval between the administration of $10^{-7}$ and $10^{-8}M$ SP. 3) The treatment of rabbit ileum by $10^{-7}M$ SP for 5 min didn't decrease the response to $10^{-6}M$ acetylcholine. 4) $10^{-6}M$ atropine had no effect of the contractile response to $10^{-7}M$ SP. The response to $10^{-7}M$ SP was normal or subnormal in the presence of 3 mM tetraethylammonium(TEA). 5) 100k solution, $10^{-4}M$ ouabain, and Na-free solution inhibited the response to $10^{-8}M$ SP and 3 mM TEA completely, and to $10^{-7}M$ SP incompletely. 3 mM TEA induced a considerable contraction in K-free solution, but $10^{-8}M$ SP didn't induce the contraction. $10^{-6}M$ norepinephrine decreased the contractile responses to SP and TEA. 6) The contractile response to $10^{-7}M$ SP was dependent on the extracellular $Ca^{2+}$ concentrations to 1.8 mM. 7) The contractile response to $10^{-7}M$ SP remained 15% of the maximal response after bathing the ileum in a Ca-free solution for 2.5 min. 8) The responsiveness to SP was completely lost within 10 min of bathing in Ca-free solution, but was restored by the exposure to $Ca^{2+}$. The restorative effect of $Ca^{2+}$ depended on the concentration of $Ca^{2+}$, and on time for which the tissue exposed to this $Ca^{2+}$ concentration. These results suggest that there are two mechanisms of the action by which the low concentrations of substance P causes the contraction of intestinal smooth muscle: the reduction of K conductance and a mechanism dependent on the extracellular $Ca^{2+}$, and that high concentration of SP may elicit a contraction by releasing $Ca^{2+}$ from an intracellular store, which is not as sensitive to removal of extracellular $Ca^{2+}$ or as easily accessible to EGTA as the extracellular space of the muscle. The location of this store is not known; it may be associated with the internal side of the cell membrane.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.158-173
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• 2012

The objectives of this study were to analyze the longitudinal gradient and temporal variations of water quality in Daecheong Reservoir in relation to the major inflowing streams from the watershed, during 2001~2010. For the study, we selected 7 main-stream sites of the reservoir along the main axis of the reservoir, from the headwater to the dam and 8 tributary streams. In-reservoir nutrients of TN and TP showed longitudinal declines from the headwater to the dam, which results in a distinct zonation of the riverine ($R_z$, M1~M3), transition ($T_z$, M4~M6), and lacustrine zone ($L_z$, M7) in water quality, as shown in other foreign reservoirs. Chlorophyll-a (CHL) and BOD as an indicator of organic matter, were maximum in the $T_z$. Concentration of total phosphorus (TP) was the highest (8.52 $mg\;L^{-1}$) on March in the $R_z$, and was the highest (165 ${\mu}g\;L^{-1}$) in the $L_z$ on July. Values of TN was the maximum (377 ${\mu}g\;L^{-1}$) on August in the $R_z$, and was the highest (3.76 $mg\;L^{-1}$) in the $L_z$ on August. Ionic dilution was evident during September~October, after the monsoon rain. The mean ratios of TN : TP, as an indicator of limiting factor, were 88, which indicates that nitrogen is a surplus for phytoplankton growth in this system. Nutrient analysis of inflowing streams showed that major nutrient sources were headwater streams of T1~T2 and Ockcheon-Stream of T5, and the most influential inflowing stream to the reservoir was T5, which is located in the mid-reservoir, and is directly influenced by the waste-water treatment plants. The key parameters, influenced by the monsoon rain, were TP and suspended solids (SS). Empirical models of trophic variables indicated that variations of CHL in the $R_z$ ($R^2$=0.044, p=0.264) and $T_z$ ($R^2$=0.126, p=0.054) were not accounted by TN, but were significant (p=0.032) in the $L_z$. The variation of the log-transformed $I_r$-CHL was not accounted ($R^2$=0.258, p=0.110) by $I_w$-TN of inflowing streams, but was determined ($R^2$=0.567, p=0.005) by $I_w$-TP of inflowing streams. In other words, TP inputs from the inflowing streams were the major determinants on the in-reservoir phytoplankton growth. Regression analysis of TN : TP suggested that the ratio was determined by P, rather than N. Overall, our data suggest that TP and suspended solids, during the summer flood period, should be reduced from the eutrophication control and P-input from Ockcheon-Stream should be controlled for water quality improvement.