• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.262-274
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• 1999

Several alternatives for increasing the fluoride concentration in the mouth, such as water fluoridation, ingestion of fluoride supplements, fluoride paste, fluoride mouthrinse, application of fluoride gel are available. There is an impressive body of evidence that the topically deliverd fluorides are clinically effective in inhibiting the progression of dental caries. Recent studies on the cariostatic action of fluoride have indicated the importance of fluoride in the fluid environment of the teeth. The fluoride levels in unstimulated whole saliva can be considered indicative of F in the aqueous phase available for interaction with the tooth surface at a given time. The retention of F in the mouth after topical fluoride treatment is considered to be an important factor in the clinical efficacy of F. The aim of this study was to determine the elevation and clearance of fluoride in whole saliv after the following topical flouride treatments using HMDS-diffusion technique and fluoride ion electrode. The obtained results were as follow: 1. Average salivary fluoride concentration in the unstimulated whole saliva was $0.0152ppm{\pm}0.0091ppm$. Unstimulated salivary flow rate was between 0.34-0.36ml/min and there was no statistically significant difference among the groups(p>0.05). 2. Except for the immediate time after treatment, fluoride levels followed as APF gel>neutral gel>F-rinse>F-paste. There was no statistical difference between the salivary F concentration of F-paste group and that of control group after 2 hours. In case of F-rinse group, after 3 hours the concentration had dropped to baseline value. But there was statistically significant difference among the F concentraion of F gel groups and that of control group(p<0.05). 3. The mean $AUC_{0-120min}$ values were followed as neutral gel>APF gel>F-rinse>F-paste, and the values of the two former groups were significantly higher than those of the two latter groups(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.38-45
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• 2009

The aim of this study was to examine efficacy of the commercially available 10% CPP-ACP cream (Tooth mousse, GC Co., Japan) and/or 0.05% NaF solution on the remineralization of artifical caries-like lesion in the bovine teeth enamel. Sixty bovine teeth were embedded in orthodontic resin and flattened. The enamel surface in 3 mm diameter was exposed with nail varnish. Specimens were stored in demineralizing solution and divided 5 groups; Group 1 (No treatment), 2 (0.05% NaF solution 1 min), 3 (Tooth mousse 3 min), 4 (After 0.05% NaF solution, Tooth mousse treatment), and 5 (After Tooth mousse treatment, soaking in 0.05% NaF solution during 1 min). After treatment by groups, all specimens was stored in artificial saliva for 30 min. After the process described as above was performed during 10 days without pH cycling, surface hardness (Vickers Hardness Number, VHN) was tested and analyzed by paired t-test and one-way ANOVA test with SPSS 14.0. In intragroup comparison between surface hardness of pre and post-treatment, group 3, 4, 5 showed statistically significant increase (P < 0.05). In intergroup comparison among surface hardness increase of all groups, difference of group 5 between pre and post-treatment ($15.80{\pm}12.21$) was the highest, and followed by group 4 ($14.27{\pm}11.73$), 3 ($4.05{\pm}5.18$), 2 ($1.15{\pm}6.83$), 1 ($0.78{\pm}6.21$). Tooth mousse can be a good alternative agent for the fluoride, and the combination use with fluoride might have the additional anticariogenic effect.

• Journal of Radiation Protection and Research
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• v.39 no.3
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• pp.127-133
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• 2014

North Korea's uranium enrichment facility is a matter of international concern. It is of particular alarming to South Korea with regard to the security and safety of the country. This situation requires continuous monitoring of the DPRK and emergency preparedness on the part of the ROK. To assess the detectability of an undeclared uranium enrichment plant in North Korea, uranium concentrations in the air at both a short and a long distance from the enrichment facility were estimated. $UF_6$ source terms were determined by using existing information on North Korean facility and data from the operation experience of enrichment plants from other countries. Using the calculated source terms, two atmospheric dispersion models (Gaussian Plume Model and HYSPLIT models) and meteorological data were used to estimate the uranium particle concentrations from the Yongbyon enrichment facility. A maximum uranium concentration and its location are dependent upon the meteorological conditions and the height of the UF6 release point. This study showed that the maximum uranium concentration around the enrichment facility was about $1.0{\times}10^{-7}g{\cdot}m^{-3}$. The location of the maximum concentration was within about 0.4 km of the facility. It has been assumed that the uranium sample of about a few micrograms (${\mu}g$) could be obtained; and that few micrograms of uranium can be easily measured with current measurement instruments. On the contrary, a uranium concentration at a distance of more than 100 kilometers from the enrichment facility was estimated to be about $1.0{\times}10^{-13}{\sim}1.0{\times}10^{-15}g{\cdot}m^{-3}$, which is less than back-ground level. Therefore, based on the results of our paper, an air sample taken within the vicinity of the Yongbyon enrichment facility could be used to determine as to whether or not North Korea is carrying out an undeclared nuclear program. However, the air samples taken at a longer distance of a few hundred kilometers would prove difficult in detecting a clandestine nuclear activities.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.378-383
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• 2001

Embryo culture, ovule culture and ovary slice culture were tested to find optimum method for overcoming post fertilization barrier in interspecific crosses between L. longiflorum 'Gelria' and L. cernuum. Although reciprocal crosses between the species were carried out by cut-style pollination method, fruits developed only in crosses of L. longiflorum${\times}$L. cernuum. On the 40 days after pollination, ovaries were sliced into 2-4mm thickness and cultured on a hormone-free Murashige-Skoog (MS) medium, supplemented with 2%, 4%, 6%, 8% and 10% sucrose. For the L. longiflorum Gelria'${\times}$L. cernuum cross, ovule development was found to be best at 6% sucrose and a lot of hybrid plant lets established directly from the ovary slice culture and subsequent ovule culture. High concentration of sucrose above 8% made ovules abort or vitrificate from 40 days after culture. In contrast, ovules from the L. cernuum${\times}$L. longiflorum 'Gelria' cross swelled well in ovary slice culture, however, they did not germinated in subsequent ovule culture. On the 60 days after pollination, ovules thicker than 0.6mm was interpreted as one containing embryo. The embryo size ranged from 1.2 mm to 1.7 mm, and in vitro development of the excised embryos was found to be best with the MS medium (pH 5.8), supplemented with $0.1-1 mg{\cdot}L^{-1}$ NAA and 6% sucrose. Thick ovules excised 60 days after pollination germinated about 60% as normal seeds in MS medium supplemented with 6% sucrose and free hormone. The ovule culture 60 days after pollination was concluded to be most recommendable to produce interspecific hybrids in large scale crosses between L. longiflorum 'Gelria' and L. cernuum by the reason of easy procedure.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.645-650
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• 2011

Pear cultivar 'Supergold' (Pyrus pyrifolia var. culta Nakai) was originated from the cross between 'Chuwhangbae' and 'Manpungbae' with the aims of improving the fruit quality of 'Chuwhangbae' cultivar at Pear Research Station of National Institute of Horticultural & Herbal Science, Rural Development Administration in 1994. 'Supergold' was preliminarily selected in 2002 and named in 2008. The tree shows a vigorous growth habit and semi-spread characters like as 'Manpungbae'. Furthermore, it has sufficient flowers and carries abundant pollen grains, so it can also be used as a pollinator. 'Supergold' is highly resistant to black leaf spot (Alternaria kikuchiana) in the field condition. The optimum harvest time is around Sep. 11th, which is ahead of 'Whangkeumbae' about 5 days in the harvest period. The fruit shape is oblate and fruit skin color is greenish-white at harvesting time. The average weight of fruit is 570 g, and the soluble solids content is $13.6\;^{\circ}Brix$. The flesh is very soft and juicy, and renders good eating quality. Shelf life is about 6 months under the cold storage condition. To determine the self-incompatibility (SI) genotype of 'Supergold' pear cultivar, it was crossed with other cultivars of which SI genotypes have already known. The result of cross-pollinations of 'Supergold' with other cultivars showed relatively high rates of fruit set from 64.5% to 91.0%, except for the cross with pollens of 'Nijisseiki' that represented only 28.8% of fruiting rate. Although sometimes the stigma of 'Supergold' crossed with 'Hayatama', 'Chojuro', and 'Nijisseiki' showed malformed pollen tube tips, 'Supergold' is generally supposed to have cross-compatibility with all other pollen donor cultivars. It is considered that the S-allele of 'Supergold' is $S_3S_4$, which is based on the result of PCR-RFLP.

• Journal of Nutrition and Health
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• v.33 no.1
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• pp.86-101
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• 2000

Various kinds of living circumstances are making population structure of Korean changed. That is, number of the children is decreased and that of the aged is increased. It is predicted that population of the children and the aged will be almost same until 2020. With above, as the expectation of the aged on healthy living might be increased, some special programs for the aged will be needed strongly. At this point, Korean aged population might be economically poor, comparing with other generation. In general, economic factor affects the subjective living-satisfaction and health status of them. Moreover, educational status, household shape and family tieing also affect their health status. According to the foreign articles, health status of the aged might be related to income, educational status, job, employed or/not, marital status, family structure, sex, and childhood condition. decrease of the income or unemployment could make the death rate of the aged higher. During childhood, discordance among the family might affect their health status after. IGUR is also important factor to affect the adulthood health. Positive life style of the aged would lessen their unequality of the health among them. Nutritional status of the Korean aged population might be indicated under the nutritional recommendation. It is affected by their income, education level, social class, and residing place. (Korean J Nutrition 33(1) : 86-101, 2000)

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.9-14
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• 1973

In order to find out effects of the generative power of silk worm moth which have been brought up in the high temperature accommodation at their pupa stage. For this specific study, 9 different kinds of male silk worms have been selected as specimen. All those specimen were brought up in the normal temperature at their larvae stage and after the pupation period they have been accommodated in the condition of high temperature for a certain length in accordance with the study programme. Afterwards, those mlae specimen were copulated with Suwon jam 103${\times}$104 which were all brought up in normal conditions. This study was carried out to find the copulation function as well as the ratio of unfertilized eggs(male sterility test). Results of study have been revealed as follows: 1) Although some differences were observed, male pura which have been brought up in the condition of high temperature shown the low rate of unfertilized eggs rather than those were brought up in the normal conpition. 2) In this group the eclosion(emergency) has been found to be poor rather, than those specimen brought up in normal conditions. 3) The copulation function of Moran, Daedong, J124 and C108 specimen were found to be poor than those of Suwon jam. 4) Fertility rate of Moran, Daedong, J124 and C108 was found to be around 65%. This figure is rather lower than what we normally expect. 5) Unfertilized egg ratio of Moran, Daedong and C108 were found to be around 20% if they were brought up in the condition of high temperature for one day from the time of pupation: 40% at 2 days, and 70% at 3 days duration. More than 3 days treatment has shown no progress in the unfertilized egg ratio. 6) One day's treatment for the pupa at the later stage has shown the unfertilized egg ratio of about 10%; 20% at 2 day's treatment, 35% at 3 day's treatment, 40-60% at 4 day's treatment, more than 60% at 5 day's treatment, and the 70% of fertilized egg ratio was only observed when the treatment days come to 7 days. It was understood that the unfertilized egg ratio was high at the antepupa stage rather than that of post-pupa stage. 7) According to the result of observation the sperm in copulatory pouch and seminal receptacle out of the normal female silk worm which have been copulated with the male brought up in the condition of high temperature at their moth stage. The reproduction system found in the control zone has been found to be normal and the sperm is amountful and active in motion while the sperm found in the treatment to be limited in amount and slow in motion. The observation was made within 5 hours from the copulation. 8) According to the result of observation of sperm of seminal receptacles of the female silkworm moth, and according to that observation of sperm in the seminal receptacle in female silkworm moth, the amount of sperm and mobility in the female moth brought up in high temperature were poor comparing that were brought up in normal temperature zone. Some of them are even found to be no trace of such. 9) Appearance and mosle of the copulatory organ of the male silkworm moth was found to be no anatomical change. 10) Testis of the later pupa stage which was brought up in the high temperature was found to be almost net developed to anucleate sperm and they are degenerated at stage of between maturation division and sperm abnormal stage. Mean time at control zone, the formation of anucleate sperm was already observed.

• Korean Journal of Plant Resources
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• v.31 no.1
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• pp.77-85
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• 2018

The cultivation area of rapeseed (Brassica napus L.) has been increased for oil production and landscaping purpose in Korea. However, as the color of rapeseed flower is very simple, diversified flower color is necessary to improve landscape effect. Interspecific and intergeneric crosses between rapeseed (Brassica napus) and three Cruciferae crops were performed in order to grow diverse flower color of rapeseed. The silique formation rate of interspecific cross rapeseed with cabbage (B. oleracea L) was relatively high (65.8%) and higher than intergeneric cross with rapeseed and radish (Raphanus sativus L.), rapeseed and Orychophragmus, respectively. During silique developing period after artificial pollination, there were many siliques without seeds due to the failure of fertilization. The average number of seed per silique obtained from cross rapeseed and cabbage, rapeseed and radish, rapeseed and O. violaceus were 0.12, 0.4 and 0.12, respectively. The phenotypes of $F_1$ hybrid plants from cross rapeseed and Cruciferae crops were mostly similar to maternal line, but leaf length and leaf width were increased. The interspecific cross of rapeseed and cabbage generated ivory color of flower which is the medium color of parents, and intergeneric cross of rapeseed and O. violaceus created entities with larger flowers which seems to enhance landscape effect. The fatty acid composition of most hybrid seeds intermediated of the two parents for oleic acid, linoleic acid and linolenic acid, content. Whereas hybrid of rapeseed and radish produced less erucic acid than radish parent.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.272-283
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• 2016

This study compared and analyzed the occluding effects of fluoride compounds and desensitizers, which are commonly used in dental clinics, on dentinal tubules. This study also evaluated the persistence of the active ingredients over time by performing toothbrushing with an electric toothbrush. Thirty-five molar teeth, which had been extracted within the past 3 months from healthy people without tooth decays, amalgam fillings, or dental crowns, were divided into 4 pieces each. Of these, 135 teeth pieces were used as study specimens. These specimens were divided into a control group, an untreated group, and 5 experimental groups (acidulated fluoride gel, fluoride varnish, Gluma, Super Seal, and SE-Bond). The specimens were then subjected to toothbrushing equivalent to 1 week (140 times), 2 weeks (280 times), and 4 weeks (560 times), and the occluding effects on dentinal tubules in 3 regions of each specimen were examined under a scanning electron microscope. The fluoride varnish treated group showed the highest degree of dentinal tubule occlusion effects during the first, second, and fourth weeks of toothbrushing, with the SE-Bond treated group showing the second highest degree and the Gluma treated group showing the lowest degree. After 4 weeks of toothbrushing, the Gluma treated group and the Super Seal treated group showed the lowest degrees of dentinal tubule occlusion effects. In summary, the fluoride varnish treated group and the SE-Bond treated group displayed higher occlusion effects even after 4 weeks of treatment than did the other experimental groups. Therefore, it is the authors' belief that fluoride varnish and SE-Bond are effective for treating dentinal hyperesthesia.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.381-390
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• 2004

The purpose of this in vitro study was to investigate the effects of Nd:YAG laser irradiation and fluorides on acid drink demineralized enamel. The materials were 30 freshly extracted permanent premolars with intact smooth enamel surfaces. They were demineralized with Coca-cola at $37^{\circ}C$ for 12hours and then irradiated by Nd:YAG laser with 6W power, $50mJ/cm^2$ energy density, and 20Hz pulse repetition. After laser irradiation, teeth were treated by three kinds of fluorides; (1)0.05% NaF fluoride solution (2)1.23% APF gel and (3)0.1%F fluoride varnish, microhardness(VHN) and Diagnodent scores were measured and the surfaces of each treated specimens were also observed with SEM under 1500 magnification. The results were as follows: 1. In the change of microhardness(VHN), it decreased to 34.68% from the initial micrhardness, increased to 78.37% after laser irradiation and increased to 82.62% after fluoride treatment, there were significant differences except when it was irradiated and treated with fluoride(P<0.05). 2. In the change of Diagnodent scores, it was decreased to 28.08% from the initial scores after demineralization, and then increased to 59.81% after laser irradiation, and increased to 82.17% after fluoride treatment. Scores were different significantly between the scores of initial, demineralization, laser irradiation and fluoride treatment(P<0.05). All the scores were not different significantly between fluoride types. 3. SEM observation showed that the lased enamel surfaces after demineralization were thermally degenerated and showed molten lava-like appearance and crater with cracks and many microholes.