• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.109-113
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• 1997

Purpose: To evaluate the differences of functional imaging patterns between conventional spoiled gradient echo (SPGR) and echo planar imaging (EPI) methods in cerebral motor cortex activation. Materials and Methods: Functional MR imaging of cerebral motor cortex activation was examined on a 1.5T MR unit with SPGR (TRfrE/flip angle=50ms/4Oms/$30^{\circ}$, FOV=300mm, matrix $size=256{\times}256$, slice thickness=5mm) and an interleaved single shot gradient echo EPI (TRfrE/flip angle = 3000ms/40ms/$90^{\circ}$, FOV=300mm, matrix $size=128{\times}128$, slice thickness=5mm) techniques in five male healthy volunteers. A total of 160 images in one slice and 960 images in 6 slices were obtained with SPGR and EPI, respectively. A right finger movement was accomplished with a paradigm of an 8 activation/ 8 rest periods. The cross-correlation was used for a statistical mapping algorithm. We evaluated any differences of the time series and the signal intensity changes between the rest and activation periods obtained with two techniques. Also, the locations and areas of the activation sites were compared between two techniques. Results: The activation sites in the motor cortex were accurately localized with both methods. In the signal intensity changes between the rest and activation periods at the activation regions, no significant differences were found between EPI and SPGR. Signal to noise ratio (SNR) of the time series data was higher in EPI than in SPGR by two folds. Also, larger pixels were distributed over small p-values at the activation sites in EPI. Conclusions: Good quality functional MR imaging of the cerebral motor cortex activation could be obtained with both SPGR and EPI. However, EPI is preferable because it provides more precise information on hemodynamics related to neural activities than SPGR due to high sensitivity.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.135-143
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• 2013

Purpose: This study was performed to obtain a quantitative evaluation of the cortical and cancellous bone graft harvestable from the mental and canine regions, and to evaluate the cortical vestibular thickness. Materials and Methods: This study collected cone-beam computed tomographic (CBCT) images of 100 Italian patients. The limits of the mental region were established: 5 mm in front of the medial margin of each mental foramen, 5 mm under the apex of each tooth present, and above the inferior mandibular cortex. Cortical and cancellous bone volumes were evaluated using SimPlant software (SimPlant 3-D Pro, Materialize, Leuven, Belgium) tools. In addition, the cortical vestibular thickness (minimal and maximal values) was evaluated in 3 cross-sections corresponding to the right canine tooth (3R), the median section (M), and the left canine tooth (3L). Results: The cortical volume was $0.71{\pm}0.23mL$ (0.27-1.96 mL) and the cancellous volume was $2.16{\pm}0.76mL$ (0.86-6.28 mL). The minimal cortical vestibular thickness was $1.54{\pm}0.41mm$ (0.61-3.25 mm), and the maximal cortical vestibular thickness was $3.14{\pm}0.75mm$ (1.01-5.83 mm). Conclusion: The use of the imaging software allowed a patient-specific assessment of mental and canine region bone availability. The proposed evaluation method might help the surgeon in the selection of the donor site by the comparison between bone availability in the donor site and the reconstructive exigency of the recipient site.

• ALGAE
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• v.22 no.2
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• pp.87-93
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• 2007

Three ecotypes of the freshwater red alga Compsopogon coeruleus (Balbis) Montagne were recorded from different freshwater and brackish water habitats of Orissa state in the east coast of India. These three had persistent differences in their branching pattern, e.g. (i) acute angle between main axis and lateral branch, (ii) equal or near to right angle between main axis and lateral branch, and (iii) short spine-like outgrowth instead of a branch in older filaments, besides having differences in the length, breadth and thickness of cortex of the thallus. Morphological observation of these taxa, and the ecological characteristics of the habitat of their occurrence is presented.

• ALGAE
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• v.31 no.4
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• pp.341-349
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• 2016

The red algal genus Amalthea was first described from New Zealand with one species, A. freemaniae. We discovered a new species of Amalthea from Korea, Amalthea rubida sp. nov., and described it based on morphology and rbcL sequences. A. rubida is characterized by a foliose, membranous and soft thallus having loosely arranged anticlinal medullary filaments, much like A. freemaniae, except for a difference of the cortex thickness in the basal part of vegetative structure. In the rbcL phylogenetic analyses, A. rubida formed a clade with A. freemaniae from New Zealand and Halymenia abyssicola from Mexico. A. rubida showed 5.7% interspecific divergence to A. freemaniae and 4.7% to H. abyssicola. Our discovery of A. rubida expands the distribution of Amalthea from the oceanic southwestern Pacific into the continental northwestern. A targeted global study is needed to fully reveal the species diversity and phylogenetic relationships of the genus Amalthea and members of the order Halymeniales.

• Korean Journal of Computational Design and Engineering
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• v.5 no.2
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• pp.122-126
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• 2000

A major mechanical problem with total hip replacement is the loosening of the femoral component. The loss of proximal support, with firm fixation distally, has been thought to be a major caused of fatigue failure of femoral stems. While many causes have been proposed, the most frequently suggested cause of the calcar resorption is the disuse atrophy of the cortex of the calcar due to the stress shielding of the proximal bone by the metal femoral stem. In this research, the new-designed stem(modified collar stem) was considered which made a hole inside stem and had a 3 mm thickness. Using the 3-dimensional finite element methods, the common collar stem and the modified colla stem was modeled and analysed. Also, the two models was compared. The results showed that the modified collar stem decreased the stress-shielding and it made a effective load transfer at the entire femoral region.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.253-257
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• 2013

This study examined the mechanism of action of a local anesthetic, lidocaine HCl. Energy transfer between the surface fluorescent probe, 1-anilinonaphthalene-8-sulfonic acid, and the hydrophobic fluorescent probe, 1,3-di(1-pyrenyl) propane, was used to determine the effect of lidocaine HCl on the thickness (D) of the synaptosomal plasma membrane vesicles (SPMV) isolated from the bovine cerebral cortex, and liposomes of the total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. The thickness (D) of the intact SPMV, SPMVTL and SPMVPL were $1.044{\pm}0.008$, $0.914{\pm}0.005$ and $0.890{\pm}0.003$ (arbitrary units, n=5) at $37^{\circ}C$ (pH 7.4), respectively. Lidocaine HCl decreased the thickness of the neuronal and model membrane lipid bilayers in a dose-dependent manner with a significant decrease in the thickness, even at 0.1 mM. The decreasing effect of lidocaine HCl on the membrane thickness might be responsible for some, but not all of its anesthetic action.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.1
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• pp.12-25
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• 2000

To demonstrate possible influences of general bone density on the mandible, histomorphometric analysis was carried out in mandibles and iliac bones and the correlation of the two bone densities was tested. Comparison of bony density in women and men over 60 years in the mandible was carried out too. Quantitative computed tomography(QCT) was taken in cross-section of mandibles at the same site where histomorphometric analysis was peformed to evaluate the reliability of QCT. The analysis included 40 cadavers with no known diseases affecting the bones. The subjects consisted of 15 females and 25 males with a mean age of 60.3 years. Spearman correlation analysis and Wilcoxon rank sum test was performed. The results were as follows. 1. There was statistically no correlation between the mandible and iliac bone in the values of corrected cortical width(CCW), cortical porosity(POR) in cortex, and total bone volume(TBV), mean trabecular plate thickness(MTPT), mean trabecular plate density(MTPD), and mean trabecular plate separation(MTPS) in trabecular bone. 2. Comparison of women and men over 60 years, men had statistically higher bone density than women except fir POR of buccal and lingual cortex, and WTPD of alveolar trabeculae in mandible. 3. There was statistically significant correlation between TBV of trabecular bone and CT No., but not between POR and CT No. in mandible. According to the results above, there was no correlation between mandible and iliac bone density and between mandibular bony density and age. Further studies are required to support the results. A more noninvasive method to be able to measure the bone density of mandible should be developed and it is necessary to accumulate data on the normal values of bone density of mandible according to age and sex. Further study should be carried out about QCT to measure mandibular bony density using QCT.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.1
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• pp.225-233
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• 1998

The purpose of this study was to determine the thickness of the cortical bone at the mandibular angle in children and adolescents. The subjects were composed of 153 subjects who were 3 to 17 years of age that had not been history of bone disease or metabolic disease and no dental caries or tooth loss on mandibular molars. The subjects were divided into three age groups, group I (preschool children) was 3 to 5 years of age and grouop II (school children) was 6 to 11 years of age and group III (adolescence) was 12 to 17 years of age. Panoramic radiographs of these patients were collected and measurements of the thickness of the cortical bone were obtained at the mandibular angle. The average thickness of the cortical bone in the group I was 1.01$\pm$0.18 mm in boys and 1.07$\pm$0.22 mm in girls. In the group II was 1.23$\pm$0.18 mm in boys and 1.32$\pm$0.18 mm in girls. In the group III was 1.60$\pm$0.23 mm in boys and 1.58$\pm$0.20 mm in girls. Statistical analyses did not reveal any significant difference between the right or left side of the mandible but difference was exist between the same age groups by sex, especially in group II (p<0.01), except in group III. The greater thickness of cortical bone in the older age group was shown to be statistically significant. The correlation coefficient between age and the thickness of the cortical bone at the mandibular angle showed a high value of r=0.76.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.620-631
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• 2022

Purpose This study aimed to investigate the diagnostic performance of features suggestive of nodal metastasis on preoperative MRI in patients with invasive breast cancer. Materials and Methods We retrospectively reviewed the preoperative breast MRI of 192 consecutive patients with surgically proven invasive breast cancer. We analyzed MRI findings of axillary lymph nodes with regard to the size, long/short ratio, cortical thickness, shape and margin of the cortex, loss of hilum, asymmetry, signal intensity (SI) on T2-weighted images (T2WI), degree of enhancement in the early phase, and enhancement kinetics. Receiver operating characteristic (ROC) analysis, chi-square test, t test, and McNemar's test were used for statistical analysis. Results Increased shorter diameter, uneven cortical shape, increased cortical thickness, loss of hilum, asymmetry, irregular cortical margin, and low SI on T2WI were significantly suggestive of metastasis. ROC analysis revealed the cutoff value for the shorter diameter and cortical thickness as 8.05 mm and 2.75 mm, respectively. Increased cortical thickness (> 2.75 mm) and uneven cortical shape showed significantly higher sensitivity than other findings in McNemar's test. Irregular cortical margins showed the highest specificity (100%). Conclusion Cortical thickness > 2.75 mm and uneven cortical shape are more sensitive parameters than other findings, and an irregular cortical margin is the most specific parameter for predicting axillary metastasis in patients with invasive breast cancer.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.114-118
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• 1997

Purpose: Functional MR imaging is the method of demonstrating changes in regional cerebral blood flow produced by sensory, motor, and any other tasks. Functional MR of visual cortex is performed as a patient stares a photic stimulation, so adaptable photic stimulation is necessary. The purpose of this study is to evaluate whether the size of photic stimulator can affect the degree of visual cortex activation. Materials and Methods: Functional MR imaging was performed in 5 volunteers with normal visual acuity. Photic stimulator was made by 39 light-emitting diodes on a plate, operating at 8Hz. The sizes of photic stimulator were full field, half field and focal central field. The MR imager was Siemens 1.5-T Magnetom Vision system, using standard head coil. Functional MRI utilized EPI sequence (TR/TE= 1.0/51. Omsec, matrix $No.=98{\times}128$, slice thickness=8mm) with 3sets of 6 imaging during stimulation and 6 imaging during rest, all 36 scannings were obtained. Activation images were obtained using postprocessing software(statistical analysis by Z-score), and these images were combined with T-1 weighted anatomical images. The activated signals were quantified by numbering the activated pixels, and activation a index was obtained by dividing the pixel number of each stimulator size with the sum of the pixel number of 3 study using 3 kinds of stimulators. The correlation between the activation index and the stimulator size was analysed. Results: Mean increase of signal intensities on the activation area using full field photic stimulator was about 9.6%. The activation index was greatest on full field, second on half field and smallest on focal central field in 4. The index of half field was greater than that of full field in 1. The ranges of activation index were full field 43-73%(mean 55%), half field 22-40 %(mean 32%), and focal central field 5-24%(mean 13%). Conclusion: The degree of visual cortex activation increases with the size of photic stimulator.