• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.247-261
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• 1999

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO, Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age $40.3{\pm}24.9$ years, range 4 to 82 years) were underwent rost/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in (rental, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018, rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was $29.9{\pm}12.9%$. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.71-76
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• 2001

In this study, the variation of astigmatism axis according to the age was studied 4227 eyes of healthy eyes. The refractive errors were measured by objective and subjective refraction. The astigmatism among the total eyes was 76.5%. With-the-rule, against-the-rule and oblique astigmatism were 51.4%, 31.7% and 16.9%, respectively. The frequency of with-the-rule was the highest and against-the-rule was the lowest of all the astigmatism in the refractive error. In relation to the age and astigmatism, the with-the-rule was 68.3% in the 10's age group which was the highest among the astigmatism and the against-the-rule was 10.3% in the 50's age group and upward which was the lowest among the astigmatism. The difference in the with-the-rule and against-the-rule ratio was a little in the 30's age group. As they aged, the tendency of the with-the-rule was increased between 10's and 20's age group continually. And the tendency of the against-the rule was increased between 30's and 50's age group and upward. There was a decrease in with-the-rule and an increase in against-the-rule, with the age increase. The oblique astigmatism relationship to age could not be determined.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.261-275
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• 1994

The annual ring widths of tree and the vertical distribution of fine roots were investigated at 33 sites of pitch pine forests in Seoul, its vicinity and rural areas. The annual ring widths among 16 - 20 year-old pitch pines in urban areas were significantly lower than those in rural areas. The annual ring widths for the latest 5 years (1985-1989) for the age class of 11-20, 21-30 and 31-40 year old pines increased in the following order for all the age classes: urban areas< suburbs

• The Journal of the Petrological Society of Korea
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• v.20 no.4
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• pp.231-241
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• 2011

Cheolwon Group in the Cheolwon Basin, which lies northwest of the Gyeonggi massif, has been correlated to the Yucheon Group in the Gyeongsang Basin, but its ages and volcanic times are defined to be considerately earlier than the other one. In this study, SHRIMP zircon U-Pb ages were determined from the igneous rocks in the Cheolwon Basin. The mean ages from zircons are $115.0{\pm}1.1Ma$ in rhyolite, and $111.24{\pm}0.85Ma$ and $109.1{\pm}1.1Ma$ in granite porphyry. The minimum age is 113 Ma in the Jijangbong Tuff. Such age in the rhyolite define the intrusion time of ring dykes, suggesting a caldera collapse following eruption of the Dongmakgol Tuff. Such age in the Jijangbong Tuff represent latest volcanism as postcaldera in the basin. The volcanic rocks in the basin were erupted during late Aptian, and are correlated to the Sindong Group in the Gyeongsang Basin. The plutonism in the basin occurred during $111.24{\pm}0.85Ma{\sim}109.1{\pm}1.1Ma$, following the volcanism. The age distribution of the analyzed zircons in the Jijangbong Tuff indicates the presence of foreign zircons derived from protoliths, regarding a wide span of zircon ages from Cretaceous to Jurassic, Triassic, early and late Protozoic, and Archean. The Archean age suggests the possible presence of the Archean protoliths with such age, which have not been exposed on the surface. The age distribution with wide span suggests that its vent is located in an area that several strata with different ages piled up and intercepted with some intrusives.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.71-75
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• 2007

This research was conducted from 1 March 2005 to 28 February 2007. We collected data from optician stores around Kwang-Ju city, 208 people aged 40 to 80 years using the cross cylinder method to find out age and gender dependence of near addition. 1. Age dependence of Refractive error shows 5% of emmetropia 34% of myopia and 43% of hyperopia. These results reveal that rate of hyperopia is higher than emmetropia and myopia. Mixed Astigmatism rate was 18%. 2. Near addition required to correct Presbyopia is analyzed as functions of gender and ages. In case of man: 40-44 (+0.75D), 45-49(+1.25D), 50-54(+1.41D), 55-59(+1.92D), 60-64(+2.35D), 65-69(+1.97D), 70(+3.12D), In case of woman: 40-44 (+1.08D), 45-49 (+1.38D), 50-54 (+1.67D), 55-59(+2.05D), 60-64 (+2.50D), 65-69 (+2.57D), $70{\leq}(+3.18D)$. Result shows it's Adding power higher than man. 3. Age dependence of Axis of Astigmatism. In case of horizontal astigmatism 61.2%, vertical 2.8% and rest else for 36%. Setting point from Binocular vision tells that average adding power of 40-44 (+0.75D) or (+1.00D), 45-49 (+1.25D) or (+1.50D), 50-54 (+1.50D), 55-59 (+2.00D), 60-64 (+2.50D), 65-69 (+2.50D) or (+2.75D), over $70{\leq}(+3.00D)$ or (+3.25D) of average adding power.

• Proceedings of the Malacological Society of Korea Conference
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• 2001.11b
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• pp.134-135
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• 2001

• 한국수산학회:학술대회논문집
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• 2005.05a
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• pp.93-94
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• 2005

• The Bulletin of The Korean Astronomical Society
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• v.8
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• pp.7.2-7.2
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• 1983

• Proceedings of the Malacological Society of Korea Conference
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• 2001.11a
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• pp.15-16
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• 2001

• Proceedings of the Korean Nutrition Society Conference
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• 2001.05a
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• pp.157.1-157
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• 2001