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Periodontal and endodontic pathology delays extraction socket healing in a canine model
Kim, Jung-Hoon,Koo, Ki-Tae,Capetillo, Joseph,Kim, Jung-Ju,Yoo, Jung-Min,Ben Amara, Heithem,Park, Jung-Chul,Schwarz, Frank,Wikesjo, Ulf M.E. Korean Academy of Periodontology 2017 Journal of Periodontal & Implant Science Vol.47 No.3
Purpose: The aim of the present exploratory study was to evaluate extraction socket healing at sites with a history of periodontal and endodontic pathology. Methods: The mandibular 4th premolar teeth in 5 adult beagle dogs served as experimental units. Periodontal and endodontic lesions were induced in 1 premolar site in each animal using wire ligatures and pulpal exposure over 3 months (diseased sites). The contralateral premolar sites served as healthy controls. The mandibular 4th premolar teeth were then extracted with minimal trauma, followed by careful wound debridement. The animals were sacrificed at days 1, 7, 30, 60, and 90 post-extraction for analysis, and the healing patterns at the healthy and diseased extraction sites were compared using radiography, scanning electron microscopy, histology, and histometry. Results: During the first 7 days of healing, a significant presence of inflammatory granulation tissue was noted at the diseased sites (day 1), along with a slightly accelerated rate of fibrin clot resolution on day 7. On day 30, the diseased extraction sites showed a greater percentage of persistent fibrous connective tissue, and an absence of bone marrow formation. In contrast, healthy sites showed initial signs of bone marrow formation on day 30, and subsequently a significantly greater proportion of mature bone marrow formation on both days 60 and 90. Radiographs exhibited sclerotic changes adjoining apical endodontic lesions, with scanning electron microscopy showing collapsed Volkmann canals protruding from these regions in the diseased sites. Furthermore, periodontal ligament fibers exhibited a parallel orientation to the alveolar walls of the diseased sites, in contrast to a perpendicular arrangement in the healthy sites. Conclusions: Within the limitations of this study, it appears that a history of periodontal and endodontic pathology may critically affect bone formation and maturation, leading to delayed and compromised extraction socket healing.
Effect of Intensity of Unconditional Stimulus on Reconsolidation of Contextual Fear Memory
Kwak, Chul-Jung,Choi, Jun-Hyeok,Bakes, Joseph T.,Lee, Kyung-Min,Kaang, Bong-Kiun The Korean Society of Pharmacology 2012 The Korean Journal of Physiology & Pharmacology Vol.16 No.5
Memory reconsolidation is ubiquitous across species and various memory tasks. It is a dynamic process in which memory is modified and/or updated. In experimental conditions, memory reconsolidation is usually characterized by the fact that the consolidated memory is disrupted by a combination of memory reactivation and inhibition of protein synthesis. However, under some experimental conditions, the reactivated memory is not disrupted by inhibition of protein synthesis. This so called "boundary condition" of reconsolidation may be related to memory strength. In Pavlovian fear conditioning, the intensity of unconditional stimulus (US) determines the strength of the fear memory. In this study, we examined the effect of the intensity of US on the reconsolidation of contextual fear memory. Strong contextual fear memory, which is conditioned with strong US, is not disrupted by inhibition of protein synthesis after its reactivation; however, a weak fear memory is often disrupted. This suggests that a US of strong intensity can inhibit reconsolidation of contextual fear memory.
Design of a 22-nm FinFET-Based SRAM With Read Buffer for Near-Threshold Voltage Operation
Juhyun Park,Younghwi Yang,Hanwool Jeong,Seung Chul Song,Wang, Joseph,Yeap, Geoffrey,Seong-Ook Jung Institute of Electrical and Electronics Engineers 2015 IEEE transactions on electron devices Vol. No.
<P>A near-threshold voltage (V<SUB>th</SUB>) operation circuit is important for both energy- and performance-constrained applications. The conventional 6-T SRAM bit-cell designed for super-V<SUB>th</SUB> operation cannot achieve the target SRAM bit-cell margins such as the hold stability, read stability, and write ability margins in the near-V<SUB>th</SUB> region. The recently proposed SRAM bit-cells with read buffer suffer from the problems of low read 0 sensing margin and large read 1 sensing time in the near-V<SUB>th</SUB> region. This paper proposes a read buffer with adjusted the number of fins or V<SUB>th</SUB> to resolve the problems in the near-V<SUB>th</SUB> region. This paper also proposes a design method for pull-up, pull-down, and pass-gate transistors to achieve the target hold stability and presents an effective write assist circuit to achieve the target write ability in the near-V<SUB>th</SUB> region.</P>
Younghwi Yang,Juhyun Park,Seung Chul Song,Wang, Joseph,Yeap, Geoffrey,Seong-Ook Jung IEEE 2015 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 1 R Vol.62 No.6
<P>As the semiconductor technology scales down, the read stability and write ability of a static random-access memory (SRAM) cell are degraded because of the increased mismatch among its transistors. Extremely thin silicon-on-insulator is one of the attractive candidates to reduce this mismatch, and it offers an independent back-gate control using a thin buried oxide. The implementation of back-gate control has recently attracted much interest to improve the read stability and write ability. In this paper, we propose a selective cell current (ICELL) boosting scheme (SIB) and an asymmetric back-gate control write-assist (ABC-WA) circuit. SIB enhances the read performance by selectively boosting ICELL of the SRAM cells. ABC-WA enhances the write ability by forward biasing the NMOSs at one side, which improves the write ability with reduction in the dynamic power overhead and without requiring a voltage generator. The proposed SRAM design improves the read performance and energy by 38.6% and 24.9%, respectively.</P>
Yang, Younghwi,Jeong, Hanwool,Song, Seung Chul,Wang, Joseph,Yeap, Geoffrey,Jung, Seong-Ook IEEE 2016 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 1 R Vol.63 No.7
<P>Although near-threshold voltage (NTV) operation is an attractive means of achieving high energy efficiency, it can degrade the circuit stability of static random access memory (SRAM) cells. This paper proposes an NTV 7T SRAM cell in a 14 nm FinFET technology to eliminate read disturbance by disconnecting the path from the bit-line to the cross-coupled inverter pair using the transmission gate. In the proposed 7T SRAM cell, the half-select issue is resolved, meaning that no write-back operation is required. A folded-column structure is applied to the proposed 7T SRAM cell to reduce the read access time and energy consumption. To reduce the standby power, the proposed 7T SRAM cell uses only a single bit-line for both read and write operations. To achieve proper '1' writing operation with a single bit-line, a two-phase approach is proposed. Compared to the conventional 8T SRAM cell, the proposed 7T SRAM cell improves the read access time, energy, and standby power by 13%, 42%, and 23%, respectively, with a 3% smaller cell area.</P>
Younghwi Yang,Juhyun Park,Seung Chul Song,Wang, Joseph,Yeap, Geoffrey,Seong-Ook Jung IEEE 2015 IEEE transactions on very large scale integration Vol.23 No.11
<P>Although near-threshold (Vth) operation is an attractive method for energy and performance-constrained applications, it suffers from problems in terms of circuit stability, particularly, for static random access memory (SRAM) cells. This brief proposes a near-Vth 9T SRAM cell implemented in a 22-nm FinFET technology. The read buffer of the proposed cell ensures read stability by decoupling the stored node from the read bit-line and improves read performance using a one-transistor read path. Energy and standby power are reduced by eliminating the sub-Vth leakage current in the read buffer. For accurate sensing yield estimation, a new yield-estimation method is also proposed, which considers the dynamic trip voltage. The proposed SRAM cell can achieve a minimum operating voltage of 0.3 V.</P>
Experimental Study on Application of an Optical Sensor to Measure Mooring-Line Tension in Waves
Nguyen Thi Thanh Diep,박지원(Ji Won Park),Van Minh Nguyen,윤현규,Jung Joseph Chul,Lee Michael Myung Sub 한국해양공학회 2022 韓國海洋工學會誌 Vol.36 No.3
Moored floating platforms have great potential in ocean engineering applications because a mooring system is necessary to keep the platform in station, which is directly related to the operational efficiency and safety of the platform. This paper briefly introduces the technical and operational details of an optical sensor for measuring the tension of mooring lines of a moored platform in waves. In order to check the performance of optical sensors, an experiment with a moored floating platform in waves is carried out in the wave tank at Changwon National University. The experiment is performed in regular waves and irregular waves with a semi-submersible and triangle platform. The performance of the optical sensor is confirmed by comparing the results of the tension of the mooring lines by the optical sensor and tension gauges. The maximum tension of the mooring lines is estimated to investigate the mooring dynamics due to the effect of the wave direction and wavelength in the regular waves. The significant value of the tension of mooring lines in various wave directions is estimated in the case of irregular waves. The results show that the optical sensor is effective in measuring the tension of the mooring lines.