Su-Yong Kim

Predominant immunoreactivity of Porphyromonas gingivalis heat shock protein in autoimmune diseases.

BACKGROUND AND OBJECTIVE Autoimmune diseases, including atherosclerosis, diabetes mellitus and rheumatoid arthritis, can be triggered and aggravated by the pathogen-driven antigenic peptide from Porphyromonas gingivalis HSP60. P. gingivalis is the major pathogen of chronic periodontitis, which is a global epidemic prevalent in two-thirds of the adult population. The monoclonal antibody raised against peptide 19 (Pep19: TLVVNRLRGSLKICAVKAPG) from P. gingivalis HSP60 was polyreactive to the human homolog. The aim of this study was to determine if Pep19 from P. gingivalis HSP60 manifests itself as a predominant antigen in infection-triggered autoimmune diseases. MATERIAL AND METHODS  Pep19 from P. gingivalis HSP60, Mycobacterium tuberculosis HSP60 and Chlamydia pneumoniae HSP60 was synthesized for comparative recognition by the sera from patients with atherosclerosis, type 2 diabetes and rheumatoid arthritis, all with ongoing periodontal disease, and by the sera of a control group of patients with periodontal disease but with no history of atherosclerosis, type 2 diabetes or rheumatoid arthritis. RESULTS Of the Pep19 peptides from P. gingivalis HSP60, M. tuberculosis HSP60 and C. pneumoniae HSP60, Pep19 from P. gingivalis HSP60 was the peptide epitope predominantly and most consistently recognized by the serum samples of the four disease groups (chronic periodontitis, atherosclerosis, type 2 diabetes mellitus and rheumatoid arthritis). CONCLUSION Seroreactivity to Pep19 of P. gingivalis HSP60, an oral pathogen, was predominant in patients with autoimmune disease with ongoing periodontal disease.

Effect of caffeic acid phenethyl ester on Prevotella intermedia lipopolysaccharide‐induced production of proinflammatory mediators in murine macrophages

BACKGROUND AND OBJECTIVE Caffeic acid phenethyl ester (CAPE) has numerous potentially beneficial properties, including antioxidant, immunomodulatory and anti-inflammatory activities. However, the effect of CAPE on periodontal disease has not been studied before. This study was designed to investigate the efficacy of CAPE in ameliorating the production of proinflammatory mediators in macrophages activated by lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease. MATERIAL AND METHODS LPS from P. intermedia ATCC 25611 was isolated by using the standard hot phenol-water method. Culture supernatants were assayed for nitric oxide (NO), interleukin (IL)-1β and IL-6. We used real-time polymerase chain reaction to quantify inducible NO synthase, IL-1β, IL-6, heme oxygenase (HO)-1 and suppressors of cytokine signaling (SOCS) 1 mRNA expression. HO-1 protein expression and levels of signaling proteins were assessed by immunoblot analysis. DNA-binding activities of NF-κB subunits were analyzed by using the enzyme-linked immunosorbent assay-based kits. RESULTS CAPE exerted significant inhibitory effects on P. intermedia LPS-induced production of NO, IL-1β and IL-6 as well as their mRNA expression in RAW264.7 cells. CAPE-induced HO-1 expression in cells activated with P. intermedia LPS, and selective inhibition of HO-1 activity by tin protoporphyrin IX attenuated the inhibitory effect of CAPE on LPS-induced NO production. CAPE did not interfere with IκB-α degradation induced by P. intermedia LPS. Instead, CAPE decreased nuclear translocation of NF-κB p65 and p50 subunits induced with LPS, and lessened LPS-induced p50 binding activity. Further, CAPE showed strong inhibitory effects on LPS-induced signal transducer and activator of transcription 1 and 3 phosphorylation. Besides, CAPE significantly elevated SOCS1 mRNA expression in P. intermedia LPS-stimulated cells. CONCLUSION Modulation of host response by CAPE may represent an attractive strategy towards the treatment of periodontal disease. In vivo studies are required to appraise the potential of CAPE further as an immunomodulator in the treatment of periodontal disease.

USAT(Ultrasonic Satellite System) for the Autonomous Mobile Robots Localization

We propose a new distance measurement method and local positioning system for the autonomous mobile robots localization. The distance measurement method is able to measure long-range distances with a high accuracy by using ultrasonic sensors. The time of flight of the ultrasonic waves include various noises is calculated accurately by the proposed period detecting method. The proposed local positioning system is composed of four ultrasonic transmitters and one ultrasonic receiver. The ultrasonic transmitter and receiver are separated but they are synchronized by RF (Radio frequency) signal. The proposed system using ultrasonic waves is represented as USAT(Ultrasonic Satellite System). USAT is able to estimate the position using the least square estimation. The experimental results show that the proposed local positioning system enables to estimate the absolute position precisely.

A Study on the Application of U-SAT System for the Indoor Positioning Technology of Ubiquitous Computing

This study presents an ultrasonic location awareness system for the ubiquitous computing with absolute position. The flight time of ultrasonic waves is determined by a period detecting technique which is able to extend the sensing range compared with traditional methods. For location awareness, ultrasonic waves are sent successively from each ultrasonic transmitter and synchronized by radio frequency (RF) signal, where the transmitting part is fixed and the receiving part is movable. To expand the recognizing range, cell matching technique and coded ultrasonic technique are introduced. The experimentation for various distances is accomplished to verify the used period detecting technique of U-SAT system. The positioning accuracy by using cell matching is also verified by finding the locations of settled points and the usability of coded ultrasonic technique is verified. As a result, the possibility of ultrasonic location awareness system for the ubiquitous computing can be discussed as a pseudo-satellite system with low cost, a high update rate, and relatively high precision, in the places where CPS is not available.

Improved Ultrasonic Satellite System for the Localization of Mobile Robots

The localization of mobile robot in environment is a major concern in mobile robot navigation. So, many kinds of localization techniques have been researched for several years. Among them, the positioning system using ultrasound has received attention. Most of these ultrasonic positioning systems to synchronize the transmitters and receivers are used for RF (Radio Frequencies). However, due to the use of RF, the interference problems can not be avoided and the performance of radio frequencies directly affects the positioning performance. So we proposed the ultrasonic positioning system without synchronizing RF. The proposed system is based on existing USAT (Ultrasonic Satellite System) adopted infrastructure transmitting type, and consists of transmitter and receiver synchronizing modules instead of the radio frequency transmitters and receiver. The ultrasonic transmitters and receivers are synchronized individually by the transmitter and receiver synchronizing modules. In order to calculate the bias between the transmitter and receiver synchronizing modules, new positioning algorithm similar to GPS was proposed. The positioning performance of the improved USAT without synchronizing RF and the validity of the proposed positioning algorithm are verified and evaluated by experiments.

Effects of daidzein on alveolar bone loss and internal microstructures of bone in a rat model of experimental periodontitis: a study using micro-computed tomography

BACKGROUND AND OBJECTIVE Daidzein is an isoflavone abundant in soybeans, kudzu root and red clover, which have been widely studied for its therapeutic potential. The present study was designed to evaluate the effects of daidzein on alveolar bone loss and internal microstructures of bone in a rat model of experimental periodontitis by assessing morphological data obtained from micro-computed tomography (micro-CT). MATERIAL AND METHODS Twenty-four male Sprague-Dawley rats were randomly assigned to the following three groups comprising eight animals each: the nonligation (NL) group; the ligation (L) group; and the ligation+daidzein (LD) group. To induce periodontitis, a 4-0 braided silk ligature was tied around the cervical area of the lower-right first molars of rats in groups L and LD. Rats in the LD group were given daily doses of daidzein (10 mg/kg of body weight) by intraperitoneal injection immediately after ligature placement. Two weeks after the placement of ligatures, mandibular block biopsies were scanned using a micro-CT system. RESULTS Daily administration of daidzein strongly suppressed the ligature-induced loss of alveolar bone height. In addition, when rats were treated with daidzein, the ligature-induced decrease in the bone volume fraction was significantly recovered. Furthermore, daidzein significantly reversed ligature-induced deteriorations in the microarchitecture parameters of trabecular bone, such as trabecular thickness, bone mineral density, trabecular separation and structure model index. CONCLUSION The study presented here demonstrates, for the first time, that daidzein effectively reduces alveolar bone destruction resulting from experimental periodontitis in rats. Further studies are necessary for the translation of this compound clinically to improve the outcomes of patients diagnosed with periodontitis.

Unmanned Navigation of Vehicle Using the Ultrasonic Satellite System

In order for a vehicle to follow a predetermined trajectory accurately, its position must be estimated accurately and reliably. In this thesis, we propose trajectory tracking control methods for unmanned vehicle and a positioning system using ultrasonic wave. The positioning problem is an important part of control problem for unmanned navigation of a vehicle. Dead Reckoning is widely used for positioning of vehicle. However this method has problems because it accumulates estimation errors. We propose a new method to increase the accuracy of position estimation using the Ultrasonic Satellite System (USAT). It is shown that we will be able to estimate the position of vehicle precisely, in which errors are not accumulated. And proposed trajectory tracking control methods include both a new path planning method and a lateral control method for vehicle. The experimental results show that the proposed methods enables exact vehicle trajectory tracking even under various environmental factors.

Modeling and robustic control of reduction car using the ultrasonic satellite system

In this paper In this paper, which is one of the part of the development for the automation system in the navigation process, covers the car system. Local detection system based on pseudo-satellite was used to be able to detect the space coordinates and the absolute location with four ultrasonic transmitters and two receivers. Using this system we get the lateral dynamic model of a reduced car by using system identification methods and design a lateral controller. The system input is the steering wheel angle of the vehicle with constant speed and the output is the yaw of the vehicle. With system identification for a basis, to achieve a control objective, we design a controller using the model equation.

Indoor Positioning System using Incident Angle Detection of Infrared sensor

In this paper, a new indoor positioning system based on incident angle measurement of infrared sensor has been suggested. Though there have been various researches on indoor positioning systems using vision sensor or ultrasonic sensor, they have not only advantages, but also disadvantages. In a new positioning system, there are three infrared emitters on fixed known positions. An incident angle sensor measures the angle differences between each two emitters. Mathematical problems to determine the position with angle differences and position information of emitters has been solved. Simulations and experiments have been implemented to show the performance of this new positioning system. The results of simulation were good. Since there existed problems of noise and signal conditioning, the experimented has been implemented in limited area. But the results were acceptable. This new positioning method can be applied to any indoor systems that need absolute position information.