An On-Demand Routing Algorithm for Mobile Wireless Networks

Yan, Huai-Zhi,Ajith P.K,Park, Dong-Won,Joo, Gi-Ho 배재대학교 공학연구소 2005 공학논문집 Vol.7 No.1

An ad hoc network is a collection of wireless mobile nodes forming a temporary network without the centralized administration. Due to the limited transmission range of wireless work interface, multiple networks “hops” maybe needed for one node to exchange data with adjacent node. In recent years, a variety of new routing protocol about ad hoc network was developed. This paper presents a new routing protocol based on the Dynamic Source Routing which is not suitable for the high mobility ad hoc network. The Enhanced DSR adapts quickly to routing changes when node movement is frequent. When a trunk route is broken, this protocol will utilize the alternative route saved in the route to discovery quickly the new route. It improves the performance of the existing DSR algorithm, so that the negative impacts from weakness of DSR are reduced.

자외선 (UVB) 노출 증가에 대한 피부암 위해도 예측 모델의 적용

신동천,이종태,정용,강나경,양지연 한국환경독성학회 1996 환경독성보건학회지 Vol.11 No.1

A decrease in stratospheric ozone probably caused by chloroflurocarbons (CFCs) emissions, has been observed large parts of the globe. It is generally accepted that if ozone levels in the stratosphere are depleted, greater amounts of shortwave ultraviolet radiation-B (UVB) will reach the earth's surface, resulting in increased incidence of nonmelanoma skin cancer. In this study, we evaluated several mathematical models, such as a power and an exponential model, and a geometric model considering the surface area of a human body part and ages for the prediction of skin cancer incidence caused by exposure to the UVB radiation. These models basically estimated the risk of skin cancer based on those measurements of the local ozone in stratosphere and UVB. Both were measured at a part of Seoul with a Dobson ozone spectrometer and Robertson-Berger UV Biometer for 1995. As a result, we calculated the point estimation applying a biological amplification factor (BAF), UVB radiation and other factors. We used a Monte-Carlo simulation technique with assumption on the distribution of each considered factor. The sensitivity analysis of model by there components conducted using Gaussian sensitivity method. The annual integral of UVB radiation was 2275 MED (minimal erythema dose)/yr. Also, an estimate of the annual amount of UVB reaching the earth's surface at a korea's latitude and altitude was 3328 MED/yr. The values of the radiation amplification factor (RAF) were ranged from 0.9 to 1.5 in Seoul. To give the effective factors required to model the prediction of skin cancer incidence caused by exposure to the UVB radiation in Korea, we studied the pros and cons of above mentioned models with the application of those parameters measured in Seoul, Korea.

롤러스케이트 선수의 운동상해발생과 예방에 대한 조사 연구

김동희,김도수,채양석,이하얀,김선호,조성채 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.1

The study was intended to research the fact of roller skate players injury. For the study, kinds and parts of injuries, skills to be hurted, facility, injured time, cause, remedy, mental response and protecting were investigated through 182 roller skate players. The results were as follows : 1. The injury body part was showed that leg was the highest and followed by knee and ankle. 2. In the cause of injury was showed as follows: skills on corner work, bank track with concrete, 200m distance. 3. In the general cause of injury was showed: chronic fatigue by over training. 4. In the treatment and participation period after injury outbreak were showed: treatment period was toward the inside 1 week and participation to play during the treatment. 5. To the injury prevention players responded warm up, and cool down and mental-concentration were needed. Supervisor, coach and players responded knee protector wearing was needed in elementary school players and helmet-chin protector wearing in general players. The game rule revision was not necessary and the agree and disagree for ground unity to resemble. Almost players to be like concrete ground.

알데히드탈수소효소 2(ALDH2) 및 CYP2E1 유전자 다형성에 따른 요중 뮤콘산 농도와 요중 8-hydroxydeoxyguanosine과의 관련성

김용대,강종원,엄상용,장연위,김성훈,김은영,이철호,문재동,김헌 대한산업의학회 2007 대한직업환경의학회지 Vol.19 No.2

Life Science : Evaluation of physicochemical properties, skin permeation and accumulation profiles of salicylic acid amide prodrugs as sunscreen agent

( Yi Dong Yan ),( Jun Ho Sung ),( Dong Won Lee ),( Jung Su Kim ),( Eun Mi Jeon ),( Dae Duk Kim ),( Dong Wuk Kim ),( Jong Oh Kim ),( Ming Guan Piao ),( Dong Xun Li ),( Chul Soon Yong ),( Han Gon Choi ) 영남대학교 약품개발연구소 2012 영남대학교 약품개발연구소 연구업적집 Vol.22 No.0

Various amide prodrugs of salicylic acid were synthesised, and their physicochemical propertiesincluding lipophilicity, chemical stability and enzymatic hydrolysis were investigated. In vivo skinpermeation and accumulation profiles were also evaluated using a combination of common permeationenhancing techniques such as the use of a supersaturated solution of permeants in an enhancer vehicle, a lipophilic receptor solution, removal of the stratum corneum and delipidisation of skin. Their capacity factor values were proportional to the degree of carbon-carbon saturation in the side chain. All these amides were highly stable in acetonitrile and glycerine. Amide prodrugs were converted tosalicylic acid both in hairless mouse liver and skin homogenates. N-dodecyl salicylamide (C12SM) showed the lowest permeation of salicylic acid in skin compared to the other prodrugs, probably due to its low aqueous solubility. It had a high affinity for the stratum corneum and its accumulation was restricted to only the uppermost layer of skin. Thus, this amide prodrug could be a safer topicalsunscreen agent with minimum potential for systemic absorption.ⓒ2011 Elsevier B.V.All rights reserved.

Study on Paper Drying Rate Based on Lattice Boltzmann Method

Yan Yan,Pan Jiangli,Dong Jixian,Sun Jian 한국펄프.종이공학회 2022 펄프.종이기술 Vol.54 No.1

The lattice Boltzmann method and the law of conservation of kinetic energy were used to simulate and analyze moisture transfer during the drying process. The effects of paper porosity, paper basis weight, drying temperature and hot air velocity on the drying char- acteristic curve were investigated. The results show that porosity has a strong influence on the drying characteristic curve in the constant drying stage but less of an influence in the falling rate drying stage. Different paper basis weights have a significant effect on drying characteristics. The greater the weight is, the longer the drying time is. Increasing the drying temperature and hot air velocity could shorten the drying time, but the effect became weaker as these parameters were increased. These results indicated that the drying efficiency cannot be significantly improved by increasing the temperature and flow rate.

Voltammetric Studies of Diazocalix[4]crown-6 for Metal Ion Sensing

Dong, Yun-Yan,Kim, Tae-Hyun,Lee, Chang-Seuk,Kim, Hyun-Jung,Lee, Jae-Hong,Lee, Joung-Hae,Kim, Ha-Suck,Kim, Jong-Seung Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.12

The complex formation between diazocalix[4]dipropyl (1) and diazocalix[4]crown-6 ether (2) with alkali, alkaline earth and transition metal ions was investigated by voltammetry. Electrochemical properties of compounds 1 and 2 and their selectivity toward metal ions were evaluated in $CH_3CN$ solution by comparison of voltammetric behaviors of two phenols in each compound. Compounds 1 and 2 showed almost same voltammetric behavior which is two irreversible oxidation peaks caused by intramolecular hydrogen bonding between two phenols in 1 and 2. While, however, upon interacting with various metal ions, 1 with two propyl ether groups showed no significant changes in voltammetry, 2 with crown ether group caused significant voltammetric changes upon the addition of $Ba^{2+}$ to 2. Their behavior is closely related to the complex formation by entrapment of metal ion into crown ether cavity, and ion-dipole interaction between metal ion and two phenolic groups in calix[4]crown-6.

Review : Purification and Characterization of a Novel Extracellular Thermostable Alkaline Protease from Streptomyces sp. M30

( Yan Xin ),( Zhibin Sun ),( Qiongzhen Chen ),( Jue Wang ),( Yicheng Wang ),( Linfeng Luogong ),( Shuhuan Li ),( Weiliang Dong ),( Zhongli Cui ),( Yan Huang ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.11

A novel alkaline protease from Streptomyces sp. M30, SapHM, was purified by ammonium sulfate precipitation, hydrophobic interaction chromatography, and DEAE-Sepharose chromatography, with a yield of 15.5% and a specific activity of 29,070 U/mg. Tryptic fragments of the purified SapHM were obtained by electrospray ionization quadrupole timeof- flight mass spectrometry. Nucleotide sequence analysis revealed that the gene sapHM contained 1,179 bp, corresponding to 392 amino acids with conserved Asp156, His187, and Ser339 residues of alkaline protease. The first 24 amino acid residues were predicted to be a signal peptide, and the molecular mass of the mature peptide was 37.1 kDa based on amino acid sequences and mass spectrometry. Pure SapHM was optimally active at 80°C in 50 mM glycine-NaOH buffer (pH 9.0), and was broadly stable at 0-50°C and pH 4.0-9.0. The protease relative activity was increased in the presence of Ni2+, Mn2+, and Cu2+ to 112%, 113%, and 147% of control, respectively. Pure SapHM was also activated by dimethylformamide, dimethyl sulfoxide, Tween 80, and urea. The activity of the purified enzyme was completely inhibited by phenylmethylsulfonyl fluoride, indicating that it is a serine-type protease. The Km and Vmax values were estimated to be 35.7 mg/ml, and 5 × 104 U/mg for casein. Substrate specificity analysis showed that SapH was active on casein, bovine serum albumin, and bovine serum fibrin.

Stable pH sensitivity of LaAlO3/SrTiO3 interfacial electronic gas

Dong Yan,Zhang Lunyong,Li Chen,Liu Yanli,Shao Pengfei,Lei Jianming,Wang Rui,Wu Di,Chen Dunjun,Zhang Rong,Zheng Youdou 한국물리학회 2022 Current Applied Physics Vol.34 No.-

Probing pH value is essential for many applications. The request of developing stable and highly sensitive pH sensor with small size are increased recently, this is a challenge to the traditional glass pH sensors. This work investigated the pH sensing performance of the novel two-dimensional electronic gas (2DEG) at the LaAlO3/ SrTiO3 heterostructure interface discovered recently. The experimental results demonstrated that the devices host excellent sensing ability to the pH value of aqueous solutions. Quite stable output current is realized for a given pH value, and the output current is linearly dependent on pH value as required by sensor applications. This work would prompt the application research of LaAlO3/SrTiO3 heterostructure and design of new generation of advanced pH sensors.

Enhanced Oral Bioavailability of Curcumin <i>via</i> a Solid Lipid-Based Self-Emulsifying Drug Delivery System Using a Spray-Drying Technique

Yan, Yi-Dong,Kim, Jung Ae,Kwak, Mi Kyung,Yoo, Bong Kyu,Yong, Chul Soon,Choi, Han-Gon Pharmaceutical Society of Japan 2011 Biological & pharmaceutical bulletin Vol.34 No.8

<P>In this study, a novel liquid self-emulsifying drug delivery system (SEDDS) containing curcumin was formulated and further developed into a solid form by a spray drying method using Aerosil 200 as the solid carrier. The optimum liquid SEDDS consisted of Lauroglycol Fcc, Labrasol and Transcutol HP as the oil phase, the surfactant and the co-surfactant at a weight ratio of 15.0 : 70.8 : 14.2 (w/w/w), respectively. There was no difference in droplet size between the emulsions obtained from the liquid and solid forms of SEDDS. Solid state characterization of the solid SEDDS was performed by scanning electron micrograph (SEM), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRPD). The drug formulated in the solid SEDDS was quickly and completely dissolved within 5 min, both in 0.1 <SMALL>N</SMALL> HCl and phosphate buffer pH 6.8 dissolution media, whereas crude curcumin powder was significantly less dissoluble. The solid SEDDS formulation was stable for at least 3 months at 40°C with 75% relative humidity. After oral administration to rats, curcumin in the solid SEDDS resulted in significant improvement in <I>in vivo</I> absorption compared with that of curcumin powder. As the dose of curcumin formulated in solid SEDDS increased from 25 to 100 mg/kg, the <I>C</I><SUB>max</SUB> and area under the drug concentration time curve (<I>AUC</I>) of curcumin were increased by 4.6 and 7.6 times, respectively. However, the over-proportional increase in the <I>AUC</I> in the higher dose group might be due to underestimation of <I>AUC</I> in the lower dose group. In conclusion, this solid SEDDS is a promising solid dosage form for poorly water-soluble curcumin.</P>