• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.1-9
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• 1996

Functional and morphological characteristics of the exocrine pancreas in genetic model BB rat of insulin dependent diabetes medllitus(IDDM) were carried out. Wistar rat was used as control animal. Flow rate of pancreatic juice, output of amylase and protein, and plasma glucose and insulin levess were examined. Also light and ultrastructural characteristics of the exocrine pancreas were observed. Pancreatic flow rate, output of amylase and protein, and insulin level were lower;glucose level was higher comparing with those of the control Wistar rat. In Wistar rat, exocrine pancreas was typical light microscopically. Zymogen granules and cell organelles were well developed in fine structure. Cell size of the periinsular acini was larger, and number of zymogen granules were more than those of the teleinsular acini. Most acinar cells were dark cells which containe well-developed RER in their cytoplasm. On the other hand, some light cells which have the dilated RER cisterns were found. In BB rat exocrine pancreas, cell size of per-and tele-insular acini similar to that of Wistar rat. The number of light cells occupied 40-50% compairing with that of Wistar rat. Zymogen granules were lower in number than that of Wistar rat and divied into three types in morphological characteristics ; type I showing normal structure, type II showing the wide hallo and small electron dense core in center of the zymogen granule and type III not having the electron dense core in the zymogen granule. The present ratio of type I, type II and type III are less than 5%, 30-40% and more than 50%, respectively.

• Korea and Global Affairs
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• v.2 no.1
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• pp.137-162
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• 2018

This paper covers the issues including geopolitical effects of sea power on sea space in East Asia and its nature in a perspective of the past and the present. This paper analyzes the significance of Sea Power which is emphasized in Mahan's Theory of Insular Dominance and grasps the geopolitical nature of Sea Power. Along with this awareness, it deals with the problem of designated strategic phenomenon that is spreading to the Pacific Ocean with the concept of the Island Chain in China in the 21st century. Around the turn of 20th century, Japan materialized the policy of Greater East Asia Co-prosperity Sphere which was planned to expand power sphere in sea space in the East Asia based on sea power and China took shape of the concept of Island Chain in the 21st century, which has divided sea space in East Asia. Under the circumstance that China's policy of island chain faced the resistance from countries in the East Asia as well as the USA, the question about whether Korea's policy of depending on sea power is valuable even in the 21st century has been raised.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.517-527
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• 2020

Layer 2/3 pyramidal neurons (L2/3 PyNs) of the cortex extend their basal dendrites near the soma and as apical dendritic tufts in layer 1, which mainly receive feedforward and feedback inputs, respectively. It is suggested that neuromodulators such as serotonin and acetylcholine may regulate the information flow between brain structures depending on the brain state. However, little is known about the dendritic compartment-specific induction of synaptic transmission in single PyNs. Here, we studied layer-specific serotonergic and cholinergic induction of long-term synaptic plasticity in L2/3 PyNs of the agranular insular cortex, a lateral component of the orbitofrontal cortex. Using FM1-43 dye unloading, we verified that local electrical stimulation to layers 1 (L1) and 3 (L3) activated axon terminals mostly located in L1 and perisomatic area (L2/3). Independent and AMPA receptor-mediated excitatory postsynaptic potential was evoked by local electrical stimulation of either L1 or L3. Application of serotonin (5-HT, 10 μM) induced activity-dependent longterm depression (LTD) in L2/3 but not in L1 inputs. LTD induced by 5-HT was blocked by the 5-HT₂ receptor antagonist ketanserin, an NMDA receptor antagonist and by intracellular Ca²⁺ chelation. The 5-HT₂ receptor agonist α-me-5-HT mimicked the LTD induced by 5-HT. However, the application of carbachol induced muscarinic receptor-dependent LTD in both inputs. The differential layer-specific induction of LTD by neuromodulators might play an important role in information processing mechanism of the prefrontal cortex.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.93-100
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• 2002

In this paper, in ordor to examine the relevant technical facts which are very instructive to revise the domestic standard for lightning protection systems, standards and technical guideline for the protection of structure against lightning were reviewed, and several issues of the domestic standards were experimentally investigated. As a consequence, the insulator of relatively low implse voltage and a large percentage of lighting rods is flashovered by relatively low impulse voltage and a lage percentage of lighting current flows through supporting mast. Thus the potential gradient in the vicinity of supporter for lighting rods is extremely increased and the role of lighting propection systems is nullified. It seems obvious that the flashover of insular supporting lighting rod can range from erratic operation of microelectronic devices to minor physical ham or even death, or costly damage electrical equipment.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.32 no.4
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• pp.129-136
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• 2021

Objectives: To investigate the relationship between brain structure and empathy in early adolescents with attention-deficit/hyperactivity disorder (ADHD). Methods: Nineteen early adolescents with ADHD and 20 healthy controls underwent 3T MRI. All the participants were assessed for different aspects of empathy using measures including the Interpersonal Reactivity Index and Empathy Quotient. Cortical thickness and subcortical structural volume based on T1-weighted scans were analyzed using FreeSurfer. Results: Cognitive empathy (t=-2.52, p=0.016) and perspective taking (t=-2.10, p=0.043) were impaired in the ADHD group compared with the control group. The cluster encompassing the left posterior insular, supramarginal, and transverse temporal cortices [cluster-wise p-value (CWP)=0.001], which are associated with emotional empathy, was significantly smaller in the ADHD group, and the volume of the left nucleus accumbens was greater than that of the control group (F=10.12, p=0.003, effect size=0.22). In the control group, the left superior temporal (CWP=0.002) and lingual cortical (CWP=0.035) thicknesses were positively associated with cognitive empathy, while the right amygdala volume was positively associated with empathic concern (Coef=14.26, t=3.92, p=0.001). However, there was no significant correlation between empathy and brain structure in the ADHD group. Conclusion: The ADHD group had a smaller volume of the cortical area associated with emotional empathy than the control group, and there was no brain region showing significant correlation with empathy, unlike in the control group.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.441-449
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• 2015

This study was conducted to screen the characteristics of external and cranial characters of Crocidura shantungensis collected from Korean Peninsula, Ulleung Island and Jeju Island. There were significant differences in head-body length (HBL), tail length (TL), ear length (EL), and hind foot length (HFL) in males and HBL, TL, and HFL in females among three populations (p<0.05). The HBL and TL in the Jeju Island population were larger (8.0 mm and 4.0 mm in lengths, respectively) than those of the Korean Peninsula population. Based on skull analysis, a total of thirteen traits showed significant differences among the three populations (p<0.05). The condylo-insicive length (CIL), maximum width of brain case (MWB), mandibular length (ML), and mandibular height (MH) in the Jeju Island population were significantly larger than those of Korean Peninsula population (p<0.05). Principle component analysis (PCA) showed that two principle components (PC) identified from the PCA affected on the body size and width of the skull, respectively. Discriminant analysis revealed that these populations could be discriminated through skull traits. These findings concluded that the Jeju Island population was greater in the size than the Korean Peninsula, suggesting that the Jeju Island shrews have successfully adapted to the island environments and they had morphologically differentiated during glacial period after natural immigration into that Island. Thus, this study supports the 'Island Rule', showing that the population is well adapted to the island environments. This may provide important information for biogeographical and ecological studies on insular animals.

• Journal of radiological science and technology
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• v.27 no.3
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• pp.31-41
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• 2004

Attention deficit hyperactivity disorder(ADHD)is one of the most common psychiatric disorders in childhood, especially school age children and persisting into adult. ADHD is affected 7.6% in our children, Korea. and persisting into $15{\sim}20%$ in adult. And it is characterized by hyperactivity, inattention and impulsivity. Brain imaging is one of way to diagnosis for ADHD. Brain imaging studies may be provide information two types - structural and functional imaging. Structural and functional images of the brain play an important role in management of neurologic and psyciatric disorders. Brain SPECT, with perfusion imaging radiopharmaceuticals is one of the appropriate test to diagnosis of neurologic and psychiatric diseases. Ther are a few studies about separated analysis between boys and girls ADHD SPECT brain images. Selection of Probability level(P-value) is very important to determind the abnormalities when analysis a data by SPM. SPM is a statistical method used for image analysis and determine statistical different between two groups-normal and ADHD. Commonly used P-value is P<0.05 in statistical analysis. The purpose of this study is to evaluation of blood flow clusters distribution, between boys and girls ADHD. The number of normal boys are 8(6-7y, average : $9.6{\pm}3.9y$) and 51(4-11y, average : $9.0{\pm}2.4$) ADHD patients, and normal girls are 4(6-12y, average : $9{\pm}2.4y$) and 13(2-13y, average $10{\pm}3.5y$) ADHD patiens. Blood flow tracer $^{99m}Tc-ethylcysteinate$ dimer(ECD) injected as rCBF agent and take blood flow images after 30 min. during sleeping by SPECT camera. The anatomical region of hyperperfusion of rCBF in boys ADHD group is posterior cingulate gyrus and hyperperfusion rate is 15.39-15.77% according to p-value. And girls ADHD group appears at posterior cerebellum, Lt. cerbral limbic lobe and Lt. Rt. cerebral temporal lobe. These areas hyperperfusion rate are 24.68-31.25%. Hypoperfusion areas in boys ADHD,s brain are Lt. cerebral insular gyrus, Lt. Rt. frontal lobe and mid-prefrontal lobe, these areas decresed blood flow as 15.21-15.64%. Girls ADHD decreased blood flow regions are Lt. cerebral insular gyrus, Lt. cerebral frontal and temporal lobe, Lt. Rt. lentiform nucleus and Lt. parietal lobe. And hypoperfusion rate is 30.57-30.85% in girls ADHD. The girls ADHD group's perfusion rate is more variable than boys. The studies about rCBF in ADHD, should be separate with boys and girls.

• Korean Journal of Plant Taxonomy
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• v.45 no.3
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• pp.213-220
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• 2015

To elucidate the origin and patterns of establishment of insular plants on Ulleungdo Island, maternally inherited chloroplast DNA, which is useful for tracing seed movements, was used. Fagus multinervis, an endemic species that dominated broadleaf deciduous forests on Ulleungdo Island, is an excellent model for such a study. To understand the diversity and spatial distribution of the chloroplast haplotypes of F. multinervis, nucleotide sequences of the psbA-trnH region were determined from 144 individuals sampled throughout the island. Results of a phylogenetic analysis of the region with close relatives of F. multinervis suggest that F. multinervis is sister to a clade of F. japonica and F. engleriana. No haplotype variation was found within F. multinervis. This remarkably low cpDNA haplotype diversity is in contrast to the findings of previous allozyme studies of F. multinervis populations that showed high genetic diversity on Ulleungdo Island. Repeated colonization during the early stage of establishment via birds that migrated from a source area where the F. multinervis cpDNA haplotype was geographically structured may have resulted in the observed pattern of haplotype diversity. Alternatively, long-distance dispersal of seeds of the progenitor of F. multinervis via birds or typhoons to Ulleungdo may have been a single event, whereas the immigration of pollen from the mainland likely occurred frequently. Comparative phylogeographic studies of other species endemic to Ulleungdo Island and their close relatives on the neighboring mainland are necessary for a more complete understanding of the evolution of the island's native species.

• Journal of the Korean earth science society
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• v.32 no.6
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• pp.602-612
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• 2011

Jeju Island, a volcanic island located in South Korea, has been one of the main targets of geophysical and/or geological studies because of its tectonic importance related to the volcanism and tectonic link to the southern part of the Korean Peninsula. Recently, as a number of broad-band magnetotelluric (MT) measurements were made, we have examined the deep part of the island. In such an insular setting, it is not easy to properly recover the deep structures such as the lower crust and the upper crust using MT data, because their low-frequency components are strongly affected by the surrounding sea of the island. In this study, we apply the sea-effect correction to the existing MT data collected at a total of 102 sites in Jeju Island. The sea-effect correction makes remarkable changes in the observed MT data at frequencies below 1 Hz, clearly indicating the existence of a conductive lower crust. The 2-D inversion results for both Jeju Southern Line (JSL) and Jeju Northern Line (JNL) show that the transition zone separating the resistive upper crust and conductive lower crust exists at a depth of 20 km on average.

• Investigative Magnetic Resonance Imaging
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• v.14 no.2
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• pp.126-133
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• 2010

Purpose : The study was to evaluate the localization of the abnormal gyral and sulcal patterns obtained by means of brain surface rendering imaging. Materials and Methods : Nineteen patients with cortical dysplasia who underwent brain surface rendering MR imaging were included in this study. We acquired MP-RAGE sequence and created the 3-D surface rendering MR images by using $VoxelPlus^{(R)}$. Anatomical locations and configurations of abnormal gyri and sulci were reviewed. Results : Abnormal gyral and sulcal patterns were seen 18 in 19 patients. The configuration and orientation of affected gyri and sulci were clearly evaluated in the brain surface rendering images. In a lissencephaly, the a cortex was not delineated and showed markedly thick and smooth gyral pattern. In a schizencephaly, there were wheel shaped broad gyral pattern around the cleft. In a hemimegalencephaly, an affected hemisphere were enlarged and displayed thick and wide gyral pattern. In CBPS, the insular cortex was exposed and the gyri of the lesion were thickened. In focal cortical dysplasia, there were irregular serrated or thick and enlarged gyri. Conclusion : Brain surface rendering MR imaging is useful for the evaluation of a detailed gyral pattern and accurate involvement site of abnormal gyri.