Fate of mesophilic aerobic bacteria and <i>Salmonella enterica</i> on the surface of eggs as affected by chicken feces, storage temperature, and relative humidity

Park, Sunhyung,Choi, Seonyeong,Kim, Hoikyung,Kim, Yoonsook,Kim, Byeong-sam,Beuchat, Larry R.,Ryu, Jee-Hoon Elsevier 2015 FOOD MICROBIOLOGY Vol.48 No.-

<P><B>Abstract</B></P> <P>We compared the microbiological quality of chicken eggshells obtained from a traditional wholesale market and a modern supermarket. We also determined the survival and growth characteristics of naturally occurring mesophilic aerobic bacteria (MAB) and artificially inoculated <I>Salmonella enterica</I> on eggshells under various environmental conditions (presence of chicken feces, temperature [4, 12, or 25?°C], and relative humidity [RH; 43 or 85%]). The populations of MAB, coliforms, and molds and yeasts on eggshells purchased from a traditional wholesale market were significantly (<I>P</I>?≤?0.05) higher than those from a modern supermarket. In the second study, when we stored uninoculated eggs under various storage conditions, the population of MAB on eggshells (4.7–4.9 log CFU/egg) remained constant for 21 days, regardless of storage conditions. However, when eggshells were inoculated with <I>S.?enterica</I> and stored under the same conditions, populations of the pathogen decreased significantly (<I>P</I>?≤?0.05) under all tested conditions. Survival of <I>S.?enterica</I> increased significantly <I>(P</I>?≤?0.05) in the presence of feces, at low temperatures, and at low RH. These observations will be of value when predicting the behavior of microorganisms on eggshells and selecting storage conditions that reduce the populations of <I>S. enterica</I> on eggshells during distribution.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Microbial levels of eggshells from traditional market and supermarket were compared. </LI> <LI> Behaviors of microbes on eggshells as affected by storage conditions were studied. </LI> <LI> Eggshells from traditional market had more microbes than those from supermarket. </LI> <LI> Populations of <I>Salmonella</I> on eggshell surfaces decreased under all tested conditions. </LI> <LI> Survival of <I>Salmonella</I> increased when stored with feces at low temperature and RH. </LI> </UL> </P>

Survival of Salmonella enterica and naturally occurring microbiota on eggshell as affected by storage temperature, relative humidity, and inoculum carrier

Sunhyung Park,Seonyeong Choi,Jee-Hoon Ryu 한국식품영양과학회 2013 한국식품영양과학회 학술대회발표집 Vol.2013 No.11

분산적 지도성: 학문토대와 개념정의 및 국내 연구동향 분석

박선형(Park, Sunhyung) 한국교육행정학회 2018 敎育行政學硏究 Vol.36 No.3

분산적 지도성은 서구의 학문공동체에서 21세기를 대표하는 가장 강력한 지도성 이론모형으로서 연구 범위와 적용 수준을 확대해가고 있다. 분산적 지도성 시각은 지도자 개인의 내생적 특성보다는 학교현장 상황에서의 조직구성원 전체의 지도성역량과 상황 요인 및 다양한 교육도구들 간의 상호작용의 총체적 활용을 주창한다. 신뢰와 협력 등의 사회적 자본이 학교공동체가 지향해야할 조직문화로서 새롭게 강조되고 있는 현 시점에서 학교조직의 탈집중화와 지도자의 권한위임이 부각될 수 있는 개념기제로서의 분산적 지도성에 대한 체계적인 분석은 교육지도성 연구체계 확립과 학교운영의 이론적 기초 확대 및 향후 발전 방향 탐색을 위한 시의적절한 교육적 의미를 가진다고 할 수 있다. 이러한 맥락에서 본 논문은 국내·외 관련 선행연구를 중심으로 분산적 지도성의 학문토대와 개념정의 및 관련 쟁점(분산적 지도성 구인영역 설정의 적절성, 연구동향의 편향성, 양적 연구 만능주의 등)을 검토해보고자 하였다. 또한, 분산적 지도성이론 발전에 선도적 역할을 수행하였던 서구학자들의 이론체계와 학문적 토대를 확인하고 국내 관련 선행연구의 내용체계를 분석하였다. This article discussed the main ideas of distributed leadership, recently being emerged in the field of educational administration, as a new alternative framework of leadership studies. Disciplinary foundation, such as distributed cognition and expanded cognition largely developed by Hutchins, conceptual definitions and research trends in distributed leadership were explored in a detailed manner. In order to understand the whole feature of leadership, the distributed perspective argues, all the situational factors by which leadership happens need to be taken into account, since the practice of leadership is "stretched over" school leaders, followers and symbolic artifacts in the situation. The article also found that only 34 papers regarding distributed leadership, manly quantitative research, are available to date since 2003 the first paper written by the author, dealing with the notion of distributed leadership, was introduced in Korea. It was pointed out that empirical evidence of the quantitative research is shown to be remarkably thin and to be derived from an inadequate conception of distributed leadership. In order to capture comprehensively dynamic aspects of social and situational distribution of leadership especially in schools, it was suggested, the employment of various research models including qualitative research methods and mixed methods research are essentially required further, as a promising avenue that substantially broadens the field of leadership studies.

Resource ReSerVation Protocol에서 QoS를 보장하는 새로운 타이머 매카니즘

박선형(Sunhyung Park),최종원(Jongwon Choe) 한국정보과학회 1997 한국정보과학회 학술발표논문집 Vol.24 No.2Ⅲ

인터넷의 사용이 급증함에 따라 MBone상의 새로운 응용들에 대한 연구 및 구현에 활발하게 이루어지고 있다. 그러나, 현재 MBone상의 막연한 순서와 시간에 대한 정보를 제공하는 것만으로는 화상회의나 기타 공동작업을 위한 프로그램을 개발하는데 큰 도움이 되지 못한다. 그래서, 메시지들을 송수신하기전에 어느 정도의 손실, 지연 등을 보장받는 메카니즘이 필요하다. 이런 요구사항을 만족하기 위해 개발되고 있는 대표적인 프로토콜로 RSVP가 있다. RSVP는 자원예약 정보를 유지, 운영하기 위해 상태(state)를 사용한다. 이 상태를 제어하기 위해 1)트리거 메세지(trigger message) 2)리프레쉬 메세지(refresh message)를 주고받는데 현재 RSVP에서는 이 메세지를 주고받는 주기(period)를 고정시켜 놓은 한계를 가지고 있다. 이러한 고정 타이머는 네트워크의 빠른 변화에 적응을 하지 못하고 메시지의 손실을 가져 올 수 있다. 그리고, 리프레쉬 되어야 할 상태의 양이 증가함에 따라 제어 메시지의 양도 같이 증가하여 대역폭이 늘어나 링크 상태를 악화시키게 된다. 본 논문에서는 멀티캐스트 라우팅 프로토콜에서 적용했던 확장성 타이머(scalable timer)를 기반으로 다이내믹한 리프레쉬 타이머 매카니즘을 이용하여 안정된 대역폭을 확보하고 패킷손실을 감소시켜 RSVP에서 좀 더 나온 QoS를 보장할 수 있는 R-scalable timer를 제안한다.

LED와 유연가공 광섬유 기술에 기반한 디지털 컬러기능 의류의 모듈화디자인 방안연구

박수진(Soojin Park),박선형(Sunhyung Park),이주현(Joohyun Lee),홍순교(Soonkyo Hong) 한국색채학회 2009 한국색채학회 학술대회 Vol.2009 No.10

안드로이드 기반 차량정보 시스템에 관한 연구

백선형(Sunhyung Beak),김정국(Jung-Guk Kim),박상현(Sang Hyun Park),주현태(Hyuntae Ju) 한국정보과학회 2010 한국정보과학회 학술발표논문집 Vol.37 No.2B

최근 안드로이드기반 스마트폰, 타블렛 PC등 다양한 응용 제품과 연구들이 이루어지고 있다. 또한 자동차가 지능화됨에 따라 차량에 장착되는 센서 및 전자제어 장치가 늘어가고 있다. 따라서 처리해야할 정보의 양이 과거에 비해 많이 들어났으며, 이러한 정보를 활용한 연구들이 활발히 이루어지고 있다. 본 논문에서는 자동차의 주행 평균 속도, 주행거리, RPM 등 차량의 정보를 수집하는 장치와 차량정보 처리를 위해 안드로이드를 하드웨어에 탑재하는 임베디드 소프트웨어 처리기술과 차량정보를 수집처리 하는 응용애플리케이션 개발에 관해 기술한다.

Well-dispersed Pd₃Pt₁ alloy nanoparticles in large pore sized mesocellular carbon foam for improved methanol-tolerant oxygen reduction reaction

An, Sunhyung,Park, Jung-Hyun,Shin, Chae-Ho,Joo, Jin,Ramasamy, Easwaramoorthi,Hwang, Jongkook,Lee, Jinwoo Elsevier 2011 Carbon Vol.49 No.4

<P><B>Abstract</B></P><P>Oxygen reduction reaction (ORR) catalysts, Pd<SUB>3</SUB>Pt<SUB>1</SUB> nanoparticles with methanol tolerance, are supported on various carbon supports: mesocellular carbon foam (MSU-F-C), CMK-3, and Vulcan XC-72. The particle size of Pd<SUB>3</SUB>Pt<SUB>1</SUB> (∼5nm) is larger than the pore size of CMK-3 (∼3nm), resulting in the agglomeration of Pd<SUB>3</SUB>Pt<SUB>1</SUB> nanoparticles on the external surface of the CMK-3. The large surface area and large pore size of MSU-F-C allows a high degree of dispersion of Pd<SUB>3</SUB>Pt<SUB>1</SUB> nanoparticles inside the pores. Due to its highly dispersed state, the Pd<SUB>3</SUB>Pt<SUB>1</SUB>/MSU-F-C shows higher ORR activity than Pd<SUB>3</SUB>Pt<SUB>1</SUB>/Vulcan XC-72 and Pd<SUB>3</SUB>Pt<SUB>1</SUB>/CMK-3. The charge transfer resistance (<I>R</I><SUB>ct</SUB>), as measured by electrochemical impedance spectroscopy, increases in the order of Pd<SUB>3</SUB>Pt<SUB>1</SUB>/CMK-3>Pd<SUB>3</SUB>Pt<SUB>1</SUB>/Vulcan XC-72>Pd<SUB>3</SUB>Pt<SUB>1</SUB>/MSU-F-C. Pd<SUB>3</SUB>Pt<SUB>1</SUB>/MSU-F-C is methanol tolerant at 400rpm in the presence of 0.5M CH<SUB>3</SUB>OH, while methanol oxidation peaks are observed in the case of Pd<SUB>3</SUB>Pt<SUB>1</SUB>/Vulcan XC-72 and Pd<SUB>3</SUB>Pt<SUB>1</SUB>/CMK-3.</P>

재식방식에 따른 정원용 삼백초와 약모밀의 경합능력 분석

류선형(Sunhyung Ryu),임민경(Min Kyung Lim),이호진(Ho Jin Lee),이문규(Moon Kyu Lee),황레홍늉(Le Hong Nhung Hoang),박형빈(Hyung Bin Park),김완순(Wan Soon Kim) 한국원예학회 2017 한국원예학회 학술발표요지 Vol.2017 No.10

Molecular identification of sweet potato accessions using ARMS-PCR based on SNPs

Hyungjun Park,Sujung Kim,Hualin Nie,Jiseong Kim,Jeongeun Lee,Sunhyung Kim 한국식물생명공학회 2020 JOURNAL OF PLANT BIOTECHNOLOGY Vol.47 No.2

The sweet potato (Ipomoea batatas [L.] Lam.) is the sixth-most important crop in the world following rice, wheat, potato, maize, and cassava. Four varieties (‘Beniharuka’, ‘Annobeni’, ‘Pungwonmi’, ‘Hogammi’) and their Japanese cultivars are broadly distributed in South Korea. In the Korean marketplace, sweet potatoes are classified by color and shape, not by variety, making it necessary to differentiate varieties for uniform production and consumption. In this study, molecular markers were developed to distinguish the four varieties of sweet potato using SNPs and genotyping-by-sequencing (GBS) analysis via a tetra-primer amplification refractory mutation system (ARMS)-PCR. The results revealed that three variety-specific fragments (164 bp and 241 bp of SNP 04-27457768 and 292 bp of SNP 03-16195623) were amplified in the ‘Beniharuka’, ‘Pungwonmi’, and ‘Annobeni’ sweet potato varieties. There were instances where some varieties produced three bands within the gel electrophoresis, indicating heterozygosity at the given SNPs loci. DNA sequencing analysis also confirmed the results of electrophoresis at the SNPs loci. Overall, these molecular markers would provide a useful, rapid, and, simple evaluation method for the Korean sweet potato marketplace, where the mixing of varieties is a serious issue.

Low-Temperature Performance Improvement of Graphite Electrode by Allyl Sulfide Additive and Its Film-Forming Mechanism

Jurng, Sunhyung,Park, Sangjin,Yoon, Taeho,Kim, Hyun-seung,Jeong, Hyejeong,Ryu, Ji Heon,Kim, Jae Jeong,Oh, Seung M. The Electrochemical Society 2016 Journal of the Electrochemical Society Vol.163 No.8

<P>This work describes the beneficial effects given by the allyl sulfide (AS)-derived surface film on the low-temperature performances of graphite electrode and the film-forming mechanism. Adding a small amount of allyl sulfide as an electrolyte additive into a Li/graphite cell increases the reversible capacity of graphite electrode to three times larger than that of the AS-free cell at -30 degrees C. Lithium plating is also suppressed by adding AS into the background electrolyte. An impedance analysis reveals that the charge transfer resistance is significantly lower in the AS-added cell at low-temperatures. When the graphite electrode is soaked in the AS-added electrolyte, allyl sulfide is spontaneously oxidized to produce the sulfur-containing surface film. The as-generated film is then electrochemically reduced during the first lithiaiton period to produce another type of the sulfur-containing film. After repeated cycling, a carbon-rich sulfur-containing film is generated near the graphite surface, while the decomposition products of background electrolyte are deposited in the outer surface region. The presence of the carbon-rich sulfur-containing film near the graphite surface seems to be responsible for the facilitation of charge transfer reaction at low temperatures. (C) 2016 The Electrochemical Society. All rights reserved.</P>