• Title/Summary/Keyword: Middle Beam

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Pattern of buccal and palatal bone density in the maxillary premolar region: an anatomical basis of anterior-middle superior alveolar (AMSA) anesthetic technique

  • Ahad, Abdul;Haque, Ekramul;Naaz, Sabiha;Bey, Afshan;Rahman, Sajjad Abdur
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.20 no.6
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    • pp.387-395
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    • 2020
  • Background: The anterior-middle superior alveolar (AMSA) anesthetic technique has been reported to be a less traumatic alternative to several conventional nerve blocks and local infiltration for anesthesia of the maxillary teeth, their periodontium, and the palate. However, its anatomic basis remains controversial. The present study aimed to determine if the pattern of cortical and cancellous bone density in the maxillary premolar region can provide a rationale for the success of the AMSA anesthetic technique. Method: Cone-beam computed tomography scans of 66 maxillary quadrants from 34 patients (16 men and 18 women) were evaluated using a volumetric imaging software for cortical and cancellous bone densities in three interdental regions between the canine and first molar. Bone density was measured in Hounsfield units (HU) separately for the buccal cortical, palatal cortical, buccal cancellous, and palatal cancellous bones. Mean HU values were compared using the Mann-Whitney U test and one-way ANOVA with post-hoc analysis. Results: Cancellous bone density was significantly lower (P ≤ 0.001) in the palatal half than in the buccal half across all three interdental regions. However, there was no significant difference (P = 0.106) between the buccal and palatal cortical bone densities at the site of AMSA injection. No significant difference was observed between the two genders for any of the evaluated parameters. Conclusions: The palatal half of the cancellous bone had a significantly lower density than the buccal half, which could be a reason for the effective diffusion of the anesthetic solution following a palatal injection during the AMSA anesthetic technique.

A study of incisive canal using a cone beam computed tomography (cone beam형 전산화 단층촬영장치를 이용한 절치관의 연구)

  • Kim Gyu-Tae;Hwang Eui-Hwan;Lee Sang-Rae
    • Imaging Science in Dentistry
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    • v.34 no.1
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    • pp.7-12
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    • 2004
  • Purpose: To investigate the anatomical structure of the incisive canal radiographically by a cone beam computed tomography. Materials and Methods: 38 persons (male 26, female 12) were chosen to take images of maxillary anterior region in dental CT mode using a cone beam computed tomography. The tube voltage were 65, 67, and 70kVp, the tube current was 7 mA, and the exposure time was 13.3 seconds. The FH plane of each person was parallel to the floor. The images were analysed on the CRT display. Results: The mean length of incisive canal was 15.87 mm±2.92. The mean diameter at the side of palate and nasal fossa were 3.49 mm±0.76 and 3.89 mm± 1.06, respectively. In the cross-sectional shape of incisive canal, 50% were round, 34.2% were ovoid, and 15.8% were lobulated. 87% of incisive canal at the side of nasal fossa have one canal, 10.4% have two canals, and 2.6% have three canals, but these canals were merged into one canal in the middle portion of palate. The mean angles of the long axis of incisive canal and central incisor to the FH plane were 110.3°±6.96 and 117.45°±7.41, respectively. The angles of the long axis of incisive canal and central incisor to the FH plane were least correlated (r= 0.258). Conclusion : This experiment suggests that a cone beam computed radiography will be helpful in surgery or implantation on the maxillary incisive area.

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Dual Backlight Unit Incorporating a Single Light Source Integrated with a Beam Splitting Reflector (광분할 반사경이 집적된 단일 광원 기반의 통합형 듀얼 백라이트 유닛)

  • Park, Chan-Kyu;Lee, Hak-Soon;Lee, Sang-Shin
    • Korean Journal of Optics and Photonics
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    • v.19 no.2
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    • pp.122-126
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    • 2008
  • Dual backlight unit incorporating a single light source integrated with a beam splitting reflector was demonstrated, providing a surface light beam for both the keypad and the display section simultaneously. The reflector was realized by aligning a groove substrate with a matching cover, and a light guiding module comprising a stack of light guide panels and prism/diffuser sheets was attached to both sides of the reflector. A light emanating from the light source-placed in the middle of the substrate-undergoes a series of reflections through the reflector to reach the input of the light guiding module. Then it is transformed into a surface light beam, which is used to irradiate the keypad and display sections simultaneously. As for the accomplished dual surface light sources, the measured average luminance and the spatial luminance uniformity were respectively about $420\;cd/m^2$ and 69% for the keypad section, and $640\;cd/m^2$ and 79% for the display section.

Cyclic response and design procedure of a weak-axis cover-plate moment connection

  • Lu, Linfeng;Xu, Yinglu;Zheng, Huixiao;Lim, James B.P.
    • Steel and Composite Structures
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    • v.26 no.3
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    • pp.329-345
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    • 2018
  • This paper systematically investigated the mechanical performance of the weak-axis cover-plate connection, including a beam end monotonic loading test and a column top cyclic loading test, and a series of parametric studies for exterior and interior joints under cyclic loading using a nonlinear finite element analysis program ABAQUS, focusing on the influences of the shape of top cover-plate, the length and thickness of the cover-plate, the thickness of the skin plate, and the steel material grade. Results showed that the strains at both edges of the beam flange were greater than the middle's, thus it is necessary to take some technical methods to ensure the construction quality of the beam flange groove weld. The plastic rotation of the exterior joint can satisfy the requirement of FEMA-267 (1995) of 0.03 rad, while only one side connection of interior joint satisfied ANSI/AISC 341-10 under the column top cyclic loading. Changing the shape or the thickness or the length of the cover-plate did not significantly affect the mechanical behaviors of frame joints no matter in exterior joints or interior joints. The length and thickness of the cover-plate recommended by FEMA 267 (1995) is also suitable to the weak-axis cover-plate joint. The minimum skin plate thickness and a design procedure for the weak-axis cover-plate connections were proposed finally.

Seismic Performance Evaluation of Welded Beam-Column Connections abricated with SHN Steel Sections (SHN 형강 보-기둥 접합부의 내진성능 평가)

  • Kim, Tae Jin;Park, JongWon;Cho, Jeong Hyuk;Kim, Hee Dong
    • Journal of Korean Society of Steel Construction
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    • v.20 no.6
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    • pp.829-838
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    • 2008
  • In this study, cyclic tests of beam-column connections composed with members applicable to the domestic low-middle rise steel buildings were conducted to develop seismic connection details and its evaluation. Connection types and material properties of the steel were testing variables and the difference between the newly developed seismic rolled section (SHN490) and existing rolled section (SM490) was also investigated. Distributions of the yield strength and the ultimate strength of the SHN490 rolled section were relatively uniform comparing to those of the SM490 rolled section Brittle fracture in the weldments of the test specimens was not observed. Instead, fracture occurred at heat-affected zones or the stress-concentrated point near the weld access hole of the beam flanges. In the case of identical rolled-section specimens, the rotational capacity and dissipated energy of the WUF-W connection was larger than those of the WUF-B connection. In the case of identical connection types, the rotational capacity and dissipated energy of the SHN490 section connection was larger than those of the WUF-B section connection.

Effect of the Thermal Lensing on stable Region, Beam Waist and Astigmatic Compensation of Z-fold Cr4+ : YAG laser Cavity (Cr4+ : YAG 레이저에서 열 렌즈 효과에 따른 공진기의 안정영역과 빔 허리 및 비점수차의 보상)

  • Lee, Bong-Yeon
    • Korean Journal of Optics and Photonics
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    • v.17 no.5
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    • pp.447-454
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    • 2006
  • We obtained analytic solutions of boundary conditions to the stable region of Z-fold $Cr^{4+}$ : YAG laser cavity when the conditions are with and without thermal tensing effect. Also we investigated the influence of the thermal tensing effect on the stability of cavity, beam waist, and astigmatic compensation using aberration transformation matrices. The thermal tensing effect almost has no influence on the stable region of the cavity when the crystal is located in the middle of two concave mirrors and when the distances from the concave mirror to the reflecting mirror and the output coupler are the same. The beam waist, however, is affected more in a tangential plane than in a sagittal plane, and so it is difficult to have astigmatic compensation when the thermal tensing effect exists. This result means that the thermal tensing effect should be considered even for the Kerr-lens mode-locking.

Evaluation of Performance of CFRP Sheet Reinforcement on RC Members Subjected to Axial Load and Flexural Moment (축력과 휨 모멘트를 받는 RC 부재의 CFRP 시트 보강에 따른 성능 평가)

  • Bae, Chan Young;Lee, Ji Hyeong;Kim, Sang Woo;Kim, Jin Sup
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.5
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    • pp.567-576
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    • 2023
  • In general, RC beam members are designed as flexural members, considering only the bending load. However, in actual buildings, axial and bending load are simultaneously applied due to the continuity between members. As a result, the bending strength of the RC beam member increases, but the displacement decreases, and cracks are mainly concentrated in the center of the beam. Therefore, in this study, the bending performance of both normal and strengthened RC beam using carbon fiber sheets subjected to combined axial and bending load was experimentally evaluated. The carbon fiber sheets were wrapped around the middle of the specimens, and axial and bending load were applied simultaneously to the beams. The magnitude of the axial force and the effects of carbon fiber sheet reinforcement on the deformed shape, bending strength, deflection, and ductility of the RC beams were analyzed. The results show that as the applied axial force increased, the maximum bending strength increased, but the ductility decreased 64%. The bending strength of the strengthened beams increased up to 27%, the maximum deflection decreased around 8% and the ductility increased by up to 43%.

Maxillary alveolar bone evaluation following dentoalveolar expansion with clear aligners in adults: A cone-beam computed tomography study

  • Marcio Antonio de Figueiredo;Fabio Lourenco Romano;Murilo Fernando Neuppmann Feres;Maria Bernadete Sasso Stuani;Jose Tarcisio Lima Ferreira;Ana Carla Raphaelli Nahas;Mirian Aiko Nakane Matsumoto
    • The korean journal of orthodontics
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    • v.53 no.4
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    • pp.264-275
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    • 2023
  • Objective: To investigate the effects of maxillary orthodontic expansion on the alveolar bone tissue in adult patients treated with aligners by using cone-beam computed tomography. Methods: Thirty patients (22 females and 8 males; mean age: 36.3 years) were treated with Invisalign® aligners. Cone-beam computed tomography and digital models were obtained before (T0) and after (T1) upper arch expansion. The bone thicknesses in the cervical, middle, and apical areas of the incisors, canines, premolar, and first molars were buccally and palatally measured, totaling 96 areas and 2,880 measurements. The buccolingual inclinations and transverse measurements of the teeth were obtained from digital models to correlate them with the bone changes. The statistical tests used were Student's t-test, analysis of variance, and Pearson's correlation tests (p < 0.05). Results: From the 96 areas evaluated, 84 revealed an increase or stability in the alveolar bone thickness and twelve displayed significant bone loss. Bone changes did not correlate with the tooth inclination and transverse measurements. Conclusions: Within the limitation of the present study, mild levels of upper arch expansion obtained with Invisalign® aligners in adult patients did not result in any clinically significant loss of alveolar bone thickness.

Change of Sprouting-related Enzymes Activities and Food Quality Characteristics of Sweetpotato Root (Ipomea batatas Lam.) by Electron Beam Irradiation (전자빔 조사에 의한 고구마의 발아관련 효소의 활성과 식품특성 변화)

  • Lim, Sung Jin;Song, Mi Seon;Lee, Gyeong Ae;Cho, Jae-Young
    • Journal of Applied Biological Chemistry
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    • v.55 no.4
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    • pp.267-272
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    • 2012
  • We investigated that electron beam irradiation is the effective method to control the sprouting of sweetpotato roots without changing of food quality characteristics. In 12 and $25^{\circ}C$ storage after electron beam irradiation, all control samples were sprouted from 6 and 4 weeks after storage, respectively. The sprouting rate of control increased with time and the rate reached to 11.2-12.4 and 70.5-74.2% at 8 weeks after 12 and $25^{\circ}C$ storage. Also, the sprouting of middle and below positioning sweetpotato roots at 12 and $25^{\circ}C$ storage after irradiation reached to 8.6-11.3 and 42.7-48.7% after a storage period of 8 weeks, respectively. However, the sprouting of all sweetpotato roots stored at $4^{\circ}C$ and upper (0-7 cm) positioning samples of box stored at 12 and $25^{\circ}C$ with electron beam was completely inhibited due to increase peroxidase and indole acetic acid (IAA) oxidase activity. Also, all samples with electron beam such as hardness, pH, sugar content, weight loss, and vitamin C and dacarotene content did not differ from that of the control. Therefore, if electron beam will be irradiated to sweetpotato roots above 0.1 kGy before packing, it will effectively inhibit their sprouting stored at $25^{\circ}C$ without the change of food quality characteristics.

A Study on the ultrasonic signals analysis for scan fish schools and seabed targets (어군 및 해저 목표물 탐지를 위한 초음파 신호분석에 관한 연구)

  • Kim Jae-Gab;Kim Won-Jung;Yang Hwa-Sup;Jeong Chan-Ju
    • Management & Information Systems Review
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    • v.2
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    • pp.95-106
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    • 1998
  • Color Echo-sounder display signals reflected from underwater objects in eight colors according to the strength of the signal. When the sea bottom is hard due to the presence of rocks, etc, the trailing on the reflection become strong signal and soft to presence of mud, etc the trailing on the reflection become weak signal. Strong signals are displayed in the color range, reddish brown, orange and yellow, in descending order of intensity. Weak signals are displayed in the range blue, light blue, cyan and green, in ascending order of intensity. Image of fish schools at or near the sea bottom vary according to the characteristics of the beam angle setting. When the angle is wide, even fish not near the bottom may be recorded as being on the seabed. A narrow angle should, therefore, be selected when you want to get an accurate recording of fish at or near the sea bottom. The condition of the sea bottom can be determinded more easily when the beam angle is wide and pulse with is long. Though the objects could be verified by the type of reflected signals which have been transformed into digital signals strong middle and weak ones, the experiments have in continue under various condition. Futhermore, the methode of measuring temperature inside the sea ought to be examined.

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