• Journal of the Korean Society of Radiology
• /
• v.81 no.1
• /
• pp.243-247
• /
• 2020

We report a rare case of hyperglycemia-related osmotic demyelination syndrome (ODS) with focus on the imaging findings. A 61-year-old man with diabetes was admitted for general weakness and severe thirst. A few days later, he complained of dysarthria, dysphasia, and dysmetria. Laboratory examinations showed significant hyperglycemia, but normal electrolyte levels. Brain MRI revealed T2-signal abnormalities that were symmetrical, non-space occupying, and located in the central pons with a peripheral sparing pattern, which were suggestive of ODS. In addition, subsequent MRI revealed progression of signal hyperintensity; however, the patient's symptoms improved.

• Imaging Science in Dentistry
• /
• v.54 no.2
• /
• pp.181-190
• /
• 2024

Purpose: This study compared sequential changes in skeletal stability and the pharyngeal airway following mandibular setback surgery involving fixation with either a titanium or a bioabsorbable plate and screws. Materials and Methods: Twenty-eight patients with mandibular prognathism undergoing bilateral sagittal split osteotomy by titanium or bioabsorbable fixation were randomly selected in this study. Lateral cephalometric analysis was conducted preoperatively and at 1 week, 3-6 months, and 1 year postoperatively. Mandibular stability was assessed by examining horizontal (BX), vertical (BY), and angular measurements including the sella-nasion to point B angle and the mandibular plane angle (MPA). Pharyngeal airway changes were evaluated by analyzing the nasopharynx, uvula-pharynx, tongue-pharynx, and epiglottis-pharynx (EOP) distances. Mandibular and pharyngeal airway changes were examined sequentially. To evaluate postoperative changes within groups, the Wilcoxon signed-rank test was employed, while the Mann-Whitney U test was used for between-group comparisons. Immediate postoperative changes in the airway were correlated to surgical movements using the Spearman rank test. Results: Significant changes in the MPA were observed in both the titanium and bioabsorbable groups at 3-6 months post-surgery, with significance persisting in the bioabsorbable group at 1 year postoperatively (2.29°±2.28°; P<0.05). The bioabsorbable group also exhibited significant EOP changes (-1.21±1.54 mm; P<0.05) at 3-6 months, which gradually returned to non-significant levels by 1 year postoperatively. Conclusion: Osteofixation using bioabsorbable plates and screws is comparable to that achieved with titanium in long-term skeletal stability and maintaining pharyngeal airway dimensions. However, a tendency for relapse exists, especially regarding the MPA.

• Journal of the Korean Society of Radiology
• /
• v.85 no.1
• /
• pp.247-251
• /
• 2024

Respiratory epithelial adenomatoid hamartoma (REAH) in the head and neck is a rare benign lesion containing glandular tissue covered with ciliated respiratory epithelium. In the head and neck, REAH of the nasal cavity, paranasal sinuses, and nasopharynx have been reported in literature. Due to rareness of REAH and insufficient knowledge of its imaging features, the diagnosis can be challenging when we encounter a non-specific cystic mass at an uncommon site in the head or neck. Here, we report the case of a pathologically confirmed REAH showing a cystic mass centered at the buccal space (retromaxillary fat pad) with CT and MRI findings.

• Advances in nano research
• /
• v.17 no.2
• /
• pp.137-147
• /
• 2024

Graphene nanoribbons (GNRs) are considered a promising alternative to graphene for future nanoelectronic applications. However, GNRs-based device modeling is still at an early stage. This research models the electronic properties of n-doped rough-edged 13-armchair graphene nanoribbons (13-AGNRs) and quantum transport properties of n-doped rough-edged 13-armchair graphene nanoribbon field-effect transistors (13-AGNRFETs) at different doping concentrations. Step-up and edge doping are used to incorporate doping within the nanostructure. The numerical real-space nearest-neighbour tight-binding (NNTB) method constructs the Hamiltonian operator matrix, which computes electronic properties, including the sub-band structure and bandgap. Quantum transport properties are subsequently computed using the self-consistent solution of the two-dimensional Poisson and Schrödinger equations within the non-equilibrium Green's function method. The finite difference method solves the Poisson equation, while the successive over-relaxation method speeds up the convergence process. Performance metrics of the device are then computed. The results show that highly doped, rough-edged 13-AGNRs exhibit a lower bandgap. Moreover, n-doped rough-edged 13-AGNRFETs with a channel of higher doping concentration have better gate control and are less affected by leakage current because they demonstrate a higher current ratio and lower off-current. Furthermore, highly n-doped rough-edged 13-AGNRFETs have better channel control and are less affected by the short channel effect due to the lower value of subthreshold swing and drain-induced barrier lowering. The inclusion of dopants enhances the on-current by introducing more charge carriers in the highly n-doped, rough-edged channel. This research highlights the importance of optimizing doping concentrations for enhancing GNRFET-based device performance, making them viable for applications in nanoelectronics.

• Tunnel and Underground Space
• /
• v.34 no.4
• /
• pp.413-420
• /
• 2024

When planning gripper TBM, which is highly applicable to urban areas, the excavation characteristics are not considered. In addition the excavation stability and constructability are degraded by installing reinforcements in the adjacent construction site considering the relaxation load theory of the pre-existing NATM. In this study, a rationalization plan for the support was proposed considering the excavation characteristics of gripper TBM when planning reinforcements for adjacent pre-existing construction. The effect of excavation on the surrounding ground was analyzed by conducting three-dimensional stability analyses considering the construction stage for each excavation phase. In NATM, relaxation phenomenon is concentrated in tunnel face due to non-supporting time occurring simultaneously with excavation, but gripper TBM supports the ground around the tunnel face through the cutter head and skin plate, simultaneously causing ground relaxation behind the skin plate. Considering these excavation characteristics, problems in reinforcement planning for adjacent construction at the study site were pointed out. A performance improvement plan for a reasonable supporting system was proposed.

• Smart Structures and Systems
• /
• v.33 no.6
• /
• pp.399-414
• /
• 2024

This study discusses the long-term deformation monitoring and shape sensing of bridge girder surfaces with an automated extraction scheme for point clouds in the Region Of Interest (ROI), invariant to the position of a Light Detection And Ranging system (LiDAR). Advanced smart construction necessitates continuous monitoring of the deformation and shape of bridge girders during the construction phase. An automated scheme is proposed for reconstructing geometric model of ROI in the presence of noisy non-stationary background. The proposed scheme involves (i) denoising irrelevant background point clouds using dimensions from the design model, (ii) extracting the outer boundaries of the bridge girder by transforming and processing the point cloud data in a two-dimensional image space, (iii) extracting topology of pre-defined targets using the modified Otsu method, (iv) registering the point clouds to a common reference frame or design coordinate using extracted predefined targets placed outside ROI, and (v) defining the bounding box in the point clouds using corresponding dimensional information of the bridge girder and abutments from the design model. The surface-fitted reconstructed geometric model in the ROI is superposed consistently over a long period to monitor bridge shape and derive deflection during the construction phase, which is highly correlated. The proposed scheme of combining 2D-3D with the design model overcomes the sensitivity of 3D point cloud registration to initial match, which often leads to a local extremum.

• The korean journal of orthodontics
• /
• v.33 no.2 s.97
• /
• pp.103-111
• /
• 2003

The Purpose of this study was to evaluate the effect of occlusion on the mechanical strength of periodontal fibers during retention periods after experimental tooth movement. In the Sprague-Dawley male rats weighing 200g or more, the ntraoral elastics were inserted into the both right and left interproximal space between upper first and second molars for tooth movement. kiter 4 days later, the left lower first, second, and third molars were extracted for differentiating the non-occlusal side from the occlusal side in the same mouth. At the same time the elastics were removed and then light cured resin was Placed in the space between upper first and second molars following undercut was made for retention bilaterally. From the beginning of retention, 7 rats were sacrificed at 0, 4, 8, 12, 16, 20 days respectively. For evaluating of magnitude on the mechanical strength of periodontal tissue, the maximal shear load of the upper first molars were measured bilateraly during extraction using Instron Universal Testing Machine. The results of this study were obtained as follows : 1. In the occlusal side, the maximal shear load was increased from no retention to retention 20 days group as time was going and statistically difference was shown from retention 12 days group (p<0.05). 2. In the non-occlusal side, the maximal shear load was increased slightly from no retention to 20 days group as time was going but there was no statistically difference (p>0.05). 3. The result compared with the maximal shear load between occlusal and nonocclusal side showed no statistically difference until retention 8 day group (p>0.05), but showed statistically difference from retention 12 day to 20day group (P<0.05). These results show that occlusion had an effect on mechanical strength of the periodontal fibers during retention periods after experimental tooth movement; therefore, it is suggested that occlusion should be considered while the retainer types and retention period are planned.

• The Korean Journal of Air & Space Law and Policy
• /
• v.35 no.2
• /
• pp.113-136
• /
• 2020

Worldwide, so-called 'over-booking' of Air Carriers is established in practice. Although not invalid, despite their current contracts, passengers can be refused boarding, which can hinder travel planning. The Korean Supreme Court ruled that an airline carrier who refused to board a passenger due to over-booking was liable for compensation under the "Nonperformance of obligation". But what the court should be thinking about is when the benefit(transport) have been disabled. Thereforeit may be considered that the impossibility of benefit (Transport) due to the rejection of boarding caused by 'Over-booking' may be not the 'subsequent impossibility', but not the 'initialimpossibility '. The legal relationship due to initial impossibility is nullity (imposibilium nulla est obligation). When benefits are initial impossibile, our civil code recognizes liability for damages in accordance with the law of "Culpa in Contrahendo", not "nonperformance of obligation". On this reason, the conclusion that the consumer will be compensated for the loss of boarding due to overbooking by the Air Carrier is the same, but there is a need to review the legal basis for the responsibility from the other side. However, it doesn't matter whether it is non-performance or Culpa in Contrahendo. Rather, the recognition of this compensation is likely to cause confusion due to unstable contractual relationships between both parties. Even for practices permitted by Air Carriers, modifications to current customary overbooking that consumers must accept unconditionally are necessary. At the same time, if Air Carriers continue to be held liable for non-performance of obligations due to overselling tickets, it can be fatal to the airline business environment that requires overbooking for stable profit margins. Therefore, it would be an appropriate measure for both Air Carriers and passengers if the Air Carrier were to be given a clearer obligation to explain (to the consumer) and, at the same time, if the explanation obligation is fulfilled, the Air Carrier would no longer be forced to take responsibility for overbooking.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.15 no.3
• /
• pp.187-199
• /
• 2013

Umbrella arch method (UAM) used for improving the stability of the tunnel ground condition has been widely applied in the tunnel construction projects due to the advantage of obtaining both reinforcement and waterproof. The purpose of this study is to develop the evaluation technique of the integrity of bore-hole in UAM by using a non-destructive test and to evaluate the possibility of being applied to the field. In order to investigate the variations of frequency depending on grouted length, the specimens with different grouted ratios are made in the two constraint conditions (free boundary condition and embedded condition). The hammer impact reflection method in which excitation and reception occur simultaneously at the head of pipe was used. The guided waves generated by hitting a pipe with a hammer were reflected at the tip and returned to the head, and the signals were received by an acoustic emission (AE) sensor installed at the head. For the laboratory experiments, the specimens were prepared with different grouted ratios (25 %, 50 %, 75 %, 100 %). In addition, field tests were performed for the application of the evaluation technique. Fast Fourier transform and wavelet transform were applied to analyze the measured waves. The experimental studies show that grouted ratio has little effects on the velocities of guided waves. Main frequencies of reflected waves tend to decrease with an increase in the grouted length in the time-frequency domain. This study suggests that the non-destructive tests using guided ultrasonic waves be effective to evaluate the bore-hole integrity of the UAM in the field.

• Korean journal of communication and information
• /
• v.84
• /
• pp.99-123
• /
• 2017

We analyzed the movie (2016/ directed by J-yong E), which is entangled in politics of gender, age, class, or sexuality, naming as "spaces of Others", using the concepts of heterotopia of Foucault. Foucault addressed three types of spaces: the realistic space where we currently live, the unrealistic and non-existent utopia, and heterotopia, which functions antithetically to reality. Thus, Foucault's heterotopia can be considered to indicate "heterogeneous spaces" in reality. The Bacchus Lady revolves a 65-year old prostitute So-Young, sells her body to old men at the parks in downtown of Seoul. Old prostitute on streets are often referred as "Bacchus Ladies", because suggest the popular energy drink a bottle of Bacchus while selling sex. The movie represents some minorities such as transgender, Tina and madam of the club, G-spot, migrant women like Camila and Aindu, and a amputee, Dohoon. Through these people's bodies, the problems such as imperials, nations, ethnics, gender, age, class are entangled in the movie. The politics of these points work and construct heterotopias in four spaces of Others. First, the spaces which ageing and death are intersected. Second, the spaces of So-Young for prostitutes, Third, the spaces of So-Young's mothering: she adopted her baby to American when he was a infant, so she have felt guilty. Fourth, the spaces for So-young's quasi-family with Minho, a Kopian boy who was abandoned by Korean father, Dohoon, who is a poor amputee, and Tina, who is a transgender singer. Fifth, the spaces of speech of So-Young as the subaltern: the subaltern does not have the language to express its own experiences. In order to listen to the words of subaltern, we must do the task of measuring the silence. This cinematic representation of So-young as the subaltern makes her speak about her situation. Finally, the spaces constructed by the movie can be connected 'heterotopia of crisis', 'heterotopia of deviation' and 'heterotopia of fantasy'. The spaces of the movie represents lives of Others, nevertheless, So-Young's Otherness through spaces of heterotopia was transformed to an absolute Other by patriarchal traits of cinematic narrative.