Botulinum toxin A injection into the anterior belly of the digastric muscle increased the posterior width of the maxillary arch in developing rats

Ahn, Janghoon,Kim, Seong-Gon,Kim, Min-Keun,Jang, Insan,Seok, Hyun Korean Association of Maxillofacial Plastic and Re 2019 Maxillofacial Plastic Reconstructive Surgery Vol.41 No.-

Background: The purpose of this study was to evaluate the effects of botulinum toxin A (BTX) injection into the anterior belly of the digastric muscle on a growing rat. Methods: Ten Sprague Dawley rats were used in this study. When the rats were 13 days old, 0.5 units of BTX was injected into the anterior belly of the digastric muscle for the experimental group (n = 5). For the control, the same volume of normal saline was injected (n = 5). The rats were sacrificed at 60 days old, and the skulls were harvested for micro-computed tomography (μCT) analysis. Results: In anthropometric analysis, the zygomatic arch and mandibular bi-condylar width were significantly lower in the experimental group than those in the control group (P = 0.025 and 0.027, respectively). The maxillary point width was significantly higher in the experimental group than that in the control group (P = 0.020). Conclusion: BTX injection into the anterior belly of the digastric muscle had effects on the maxillofacial bony width in growing rats.

Assessment of the proximity between the mandibular third molar and inferior alveolar canal using preoperative 3D-CT to prevent inferior alveolar nerve damage

Lee, Byeongmin,Park, Youngju,Ahn, Janghoon,Chun, Jihyun,Park, Suhyun,Kim, Minjin,Jo, Youngserk,Ahn, Somi,Kim, Beulha,Choi, Sungbae Korean Association of Maxillofacial Plastic and Re 2015 Maxillofacial Plastic Reconstructive Surgery Vol.37 No.-

Background: The inferior alveolar nerve (IAN) may be injured during extraction of the mandibular third molar, causing severe postoperative complications. Many methods have been described for evaluating the relative position between the mandibular third molar and the inferior alveolar canal (IAC) on panoramic radiography and computed tomography, but conventional radiography provides limited information on the proximity of these two structures. The present study assessed the benefits of three-dimensional computed tomography (3D-CT) prior to surgical extraction of the mandibular third molar, to prevent IAN damage. Methods: This retrospective study included 4917 extractions in 3555 patients who presented for extraction of the mandibular third molars. The cases were classified into three groups, according to anatomical relationship between the mandibular third molars and the IAC on panoramic radiography and whether 3D-CT was performed. Symptoms of IAN damage were assessed using the touch-recognition test. Data were compared using the chi-square test and Fisher's exact test. Results: Among the 32 cases of IAN damage, 6 cases were included in group I (0.35 %, n = 1735 cases), 23 cases in group II (1.1 %, n = 2063 cases), and 3 cases in group III (0.27 %, n = 1119 cases). The chi-square test showed a significant difference in the incidence of IAN damage between groups I and II. No significant difference was observed between groups I and III using Fisher's exact test. In the 6 cases of IAN damage in group I, the mandibular third molar roots were located lingual relative to the IAC in 3 cases and middle relative to the IAC in 3 cases. The overlap was ${\geq}2mm$ in 3 of 6 cases and 0-2 mm in the remaining 3 cases. The mean distance between the mandibular third molar and IAC was 2.2 mm, the maximum distance 12 mm, and the minimum distance 0.5 mm. Greater than 80 % recovery was observed in 15 of 32 (46.8 %) cases of IAN damage. Conclusions: 3D-CT may be a useful tool for assessing the three-dimensional anatomical relationship and proximity between the mandibular third molar and IAC in order to prevent IAN damage during extraction of mandibular third molars.

압축센싱 디지털 수신기 신호처리 로직 구현

안우현,송장훈,강종진,정웅,Ahn, Woohyun,Song, Janghoon,Kang, Jongjin,Jung, Woong 한국군사과학기술학회 2018 한국군사과학기술학회지 Vol.21 No.4

This paper describes the real-time logic implementation of orthogonal matching pursuit(OMP) algorithm for compressive sensing digital receiver. OMP contains various complex-valued linear algebra operations, such as matrix multiplication and matrix inversion, in an iterative manner. Xilinx Vivado high-level synthesis(HLS) is introduced to design the digital logic more efficiently. The real-time signal processing is realized by applying dataflow architecture allowing functions and loops to execute concurrently. Compared with the prior works, the proposed design requires 2.5 times more DSP resources, but 10 times less signal reconstruction time of $1.024{\mu}s$ with a vector of length 48 with 2 non-zero elements.

개인의 동적능력, 기업역량이 경영성과에 미치는 영향에 관한 연구: 기술지향성의 매개효과와 정부지원정책의 조절효과

장민(Min Zhang),안세연(Seyeon Ahn),김장훈(Janghoon Kim) 한국통상정보학회 2021 통상정보연구 Vol.23 No.1

본 연구는 대전지역 스마트부품 중소업체 직원의 동적능력 및 기업역량이 기업의 경영성과에 미치는 영향을 분석하는 연구이다. 대전지역 스마트부품 중소업체를 대상으로 설문조사를 통해 127부의 자료를 수집하였다. 자료 분석결과는 직원의 변환융합능력 및 기업역량이 기술지향성에 긍정적인 영향을 미치는 한편, 기술지향성이 경영성과에 긍정적인 영향을 미치는 것으로 검증되었다. 또는 기술지향성은 부분 또는 완전 매개효과 있는 것으로 나타났고, 정부지원정책은 조절효과가 없는 것으로 나타났다. 본 연구의 결과는 스마트부품 중소업체에게 직원의 동적능력이 기업성장에 매우 중요한 역량이 되는 것을 확인되었고, 더 나아가 기술 주도 중소 부품업체에게 실질적 도움이 되도록 맞춤형 지원책의 입안과 실행의 중요성을 제안할 수 있다. This study analyzes the dynamic capabilities of employees of small and medium-sized Smart Parts companies in Daejeon and the impact of corporate capabilities on the company s management performance. 127 copies of data were collected through a survey of small and medium-sized Smart Parts businesses in Daejeon. The data analysis results proved that employees convergence and corporate capabilities have a positive impact on technology orientation, while technology orientation has a positive impact on management performance. Alternatively, technology orientation was found to be partially or fully mediated, and government support policies were found to be ineffective. The results of this study confirmed that the dynamic capability of employees is a very important capability for business growth for small and medium-sized Smart Parts companies, and further suggest the importance of customized support measures to help technology-driven small and medium-sized parts companies.

Biomechanical analysis of distalization of mandibular molars by placing a mini-plate

Myungsoon Park,Yonghyun Na,Minbong Park,Janghoon Ahn 대한치과교정학회 2017 대한치과교정학회지 Vol.47 No.5

Objective: The objective of this study was to analyze the patterns of tooth movements when distalization of mandibular molars using a mini-plate took place. A finite element analysis was applied to analyze patterns of tooth movements. Methods: The model of the mandible and teeth were used to build a finite element analysis model, and a mini-plate was inserted in the mandibular ramus. Two different orthodontic forces were established for displacement of mandibular molars. Orthodontic forces were applied at the level of the bracket and at the level of the cemento-enamel junction in the mandibular canine respectively. Results: Applying orthodontic forces at the level of the cemento-enamel junction resulted in a greater biomechanical bodily movement in distalization of the mandibular molars compared to when the orthodontic forces were applied at the level of the bracket. Applying orthodontic forces to the cemento-enamel junction also resulted in unwanted greater extrusive movements in distalization of the mandibular molars compared to the bracket level. Conclusions: With considering the mode of orthodontic teeth movement, applying different vertical orthodontic forces for distalization of mandibular molars can lead to more effective distalization of teeth.

Assessment of anterior-posterior jaw relationships in Korean adults using the nasion true vertical plane in cone-beam computed tomography images

Youngju Park,Youngserk Cho,James Mah,Janghoon Ahn 대한치과교정학회 2016 대한치과교정학회지 Vol.46 No.3

Objective: The aims of this study were to investigate a simple method for assessing anterior-posterior jaw relationships via cone-beam computed tomography (CBCT) images taken in the natural head position (NHP) relative to the nasion true vertical plane (NTVP), and measure normative data in Korean adults with normal profiles. Methods: Subjects were selected from patients presenting for third molar extraction and evaluated as having normal profiles by three examiners. The CBCT images of 80 subjects (39 males, 41 females) were taken in the NHP according to Solow and Tallgren’s method. Linear measurements of the A-point, B-point, and Pog were calculated relative to the NTVP. Student’s t -test was used to assess sexual differences in these measurements. Results: The mean linear measurements of the A-point, B-point, and Pog relative to the NTVP were 0.18 mm (standard deviation [SD], 4.77 mm), −4.00 mm (SD, 6.62 mm), and −2.49 mm (SD, 7.14 mm) respectively in Korean males, and 1.48 mm (SD, 4.21 mm), −4.07 mm (SD, 6.70 mm) and −2.91 mm (SD, 7.25 mm) in Korean females respectively. There were no statistically significant differences between Korean males and females (p < 0.05). Conclusions: Threedimensional CBCT analysis using the NTVP is a simple and reliable method for assessing anterior-posterior skeletal relationships.

Effect of the masseter muscle injection of botulinum toxin A on the mandibular bone growth of developmental rats

Seok, Hyun,Kim, Seong-Gon,Kim, Min-Keun,Jang, Insan,Ahn, Janghoon Korean Association of Maxillofacial Plastic and Re 2018 Maxillofacial Plastic Reconstructive Surgery Vol.40 No.-

Background: The objective of this study was to evaluate the influence of masticatory muscle injection of botulinum toxin type A (BTX-A) on the growth of the mandibular bone in vivo. Methods: Eleven Sprague-Dawley rats were used, and BTX-A (n = 6) or saline (n = 5) was injected at 13 days of age. All injections were given to the right masseter muscle, and the BTX-A dose was 0.5 units. All of the rats were euthanized at 60 days of age. The skulls of the rats were separated and fixed with 10% formalin for micro-computed tomography (micro-CT) analysis. Results: The anthropometric analysis found that the ramus heights and bigonial widths of the BTX-A-injected group were significantly smaller than those of the saline-injected group (P < 0.05), and the mandibular plane angle of the BTX-A-injected group was significantly greater than in the saline-injected group (P < 0.001). In the BTX-A-injected group, the ramus heights II and III and the mandibular plane angles I and II showed significant differences between the injected and non-injected sides (P < 0.05). The BTX-A-injected side of the mandible in the masseter group showed significantly lower mandibular bone growth compared with the non-injected side. Conclusion: BTX-A injection into the masseter muscle influences mandibular bone growth.