Tuning the Microstructure and Mechanical Properties of Cold Sprayed Equiatomic CoCrFeMnNi High-Entropy Alloy Coating Layer

Ji‑Eun Ahn,Young‑Kyun Kim,Sang‑Hoon Yoon,Kee‑Ahn Lee 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

An equiatomic CoCrFeMnNi high entropy alloy (HEA) coating layer was prepared via a cold spray (CS) process. In orderto control the microstructure and nano-indentation properties of the CS HEA, heat treatments were employed. CS HEAcoating layer showed a heterogeneous microstructure where ultra-fine grains were formed at the particle interfaces, whilecoarse grains were formed inside the particles. Furthermore, deformation twins (DTs) were also formed inside the particlesdue to severe plastic deformation (SPD) in each particle generated during the CS deposition. For the 550 °C heat treatment(HT), fine Cr-rich precipitates were additionally formed at the grain boundary and particle boundary. By contrast, recrystallizationoccurred during 850 °C HT, while the size of the Cr-rich precipitate increased. The nano-indentation hardness ofthe CS HEA coating layer was 10.9 GPa, which was ~ 3 times higher than that of the conventional cast HEA. The superiorhardness of the CS HEA might has been enabled due to the combination of the high dislocation density, DTs, and ultra-finegrains. Based on the results above, the strategy to control the microstructure and mechanical properties through HT of theequiatomic CoCrFeMnNi HEA coating layer prepared via the CS process has been discussed.

The Beneficial Effect of Adenophorae Radix on DSS‐induced Colitis in Mice

Ji?Wook Jung,Sa?Rang Oh,Eun?Mi Ahn,Eun?Ju Yang,Su?Jin Kim 대한의생명과학회 2013 Biomedical Science Letters Vol.19 No.3

Ulcerative colitis (UC) is an inflammatory bowel disease, which is a chronic gastrointestinal disorder. Adenophorae Radix (AR) has been used as a traditional medicine for various diseases including strengthening cardiac function, allaying a fever, and easing pain and cough. However, the regulatory effects of AR in intestinal inflammation are not yet understood. This study attempted to determine the effect of AR in dextran sulfate sodium (DSS) ? induced colitis in mice. The colitis mice were induced by drinking water containing 5% DSS for 7 days. The results showed that mice treated with DSS showed remarkable clinical signs, including weight loss, and reduced colon length. Administration of AR attenuated weight loss, colon shortening and inhibited the levels of interleukin (IL) ? 6 in DSS ? treated colon tissues. These results provide experimental evidence that AR might be a useful therapeutic medicine for patients with UC.

대한방사선종양학회지 게재 논문의 통계적 오류 현황

박희철(Hee Chul Park),최두호(Doo Ho Choi),안성복(Song-Vogue Ahn),강진오(Jin Oh Kang),김은석(Eun-Seog Kim),박원(Won Park),안승도(Seung Do Ahn),양대식(Dae Sik Yang),윤형근(Hyong Geun Yun),정은지(Eun Ji Chung),지의규(Eui Kyu Chie),표홍렬( 대한방사선종양학회 2008 Radiation Oncology Journal Vol.26 No.4

목 적: 본 연구는 대한방사선종양학회지 게재 논문의 통계 오류 현황을 파악하고 이에 근거한 문제 제기를 통해 학회지의 학술적 발전에 기여하고자 하였다. 대상 및 방법: 2006∼2007년 사이에 대한방사선종양학회지에 게재된 총 77편의 논문을 연구 대상으로 하였다. 각각의 논문에 적용된 통계 방법론의 적정성 평가는 통계점검표를 활용하였다. 통계점검표에는 연구의 종류, 통계기법의 사용 범위, 각 논문에 적용된 통계 기법의 종류, 통계적 기법 적용의 타당성 항목이 포함되었다. 통계 오류는 ‘생략의 잘못’과 ‘시행의 잘못’ 항목으로 나누었다. 한 논문에서 서로 다른 항목이 여러 가지 관찰된 경우 각각 횟수로 측정하였다. 같은 항목이 2회 이상 측정된 경우 1회로 횟수를 측정하였다. 통계 전문가가 개별 논문을 대상으로 통계점검표를 작성하였다. 일차 평가자가 방사선종양학 전문가가 아닌 것에서 올 수 있는 평가 오류가 있을 수 있으므로 개별 통계점검표는 간행위원회에서 한 차례 더 세부 점검을 하였다. 작성된 통계점검표의 통계 분석은 SAS (version 9.0, SAS Institute, NC, USA) 소프트웨어를 이용하였고 빈도분석을 시행하여 각 항목의 빈도와 백분율을 산출하였다. 결 과: 총 77편 중 원문을 다운로드 할 수 없었던 4편을 제외한 73편의 게재 논문을 대상으로 평가하였다. 증례보고는 5편, 원저 논문은 68편이었다. 대상 논문 중 46편의 논문에서 통계적 추론을 사용하였고, 16편의 논문에서 단순한 기술통계를 사용했으며, 11편의 논문에서는 통계적 기법을 사용하지 않았다. 추론통계를 사용한 46편의논문에서 사용된 추론통계의 횟수는 각각 분할표분석 17회(37.0%), 비교통계분석 23회(50.0%), 회귀분석 7회(15.2%), 상관분석 5회(10.9%), 생존분석이 27회(58.7%)였다. 통계 기법을 활용하여 연구 결과를 분석할 때 통계적용의 오류가 없는 논문은 19%였다. ‘생략의 잘못’은 34편(50.0%)의 논문에서 총 50회 관찰되었다. ‘시행의 잘못’은 35편(51.5%)의 논문에서 총 47회 관찰되었다. ‘생략의 잘못’과 ‘시행의 잘못’이 모두 발견된 논문은 21편 (30.9%)이었다.결 론: 대한방사선종양학회지에 게재된 논문에서 통계 분석 과정의 다양한 영역에 걸쳐 크고 작은 통계적 오류가 있음을 확인하였다. 향후 대한방사선종양학회지 투고 논문의 심사 과정에서 통계 오류에 관한 적절한 심사를 추가하는 것이 필요하다고 판단된다. Purpose: To improve the quality of the statistical analysis of papers published in the Journal of the Korean Society for Therapeutic Radiology and Oncology (JKOSTRO) by evaluating commonly encountered errors. Materials and Methods: Papers published in the JKOSTRO from January 2006 to December 2007 were reviewed for methodological and statistical validity using a modified version of Ahn’s checklist. A statistician reviewed individual papers and evaluated the list items in the checklist for each paper. To avoid the potential assessment error by the statistician who lacks expertise in the field of radiation oncology; the editorial board of the JKOSTRO reviewed each checklist for individual articles. A frequency analysis of the list items was performed using SAS (version 9.0, SAS Institute, NC, USA) software. Results: A total of 73 papers including 5 case reports and 68 original articles were reviewed. Inferential statistics was used in 46 papers. The most commonly adopted statistical methodology was a survival analysis (58.7%). Only 19% of papers were free of statistical errors. Errors of omission were encountered in 34 (50.0%) papers. Errors of commission were encountered in 35 (51.5%) papers. Twenty-one papers (30.9%) had both errors of omission and commission. Conclusion: A variety of statistical errors were encountered in papers published in the JKOSTRO. The current study suggests that a more thorough review of the statistical analysis is needed for manuscripts submitted in the JKOSTRO.

전신마취 후 점액으로 인한 기관내관 폐쇄 : 증례보고 A case report

안기량,엄희상,김지은 순천향의학연구소 2004 Journal of Soonchunhyang Medical Science Vol.10 No.2

Nasotracheal intubation is commonly and safely used in the anesthetic management of patients undergoing oral cavity surgery. But endotracheal tube obstruction causes serious complications, including pneumothorax, pulmonary edema, brain injury and death. We experienced a case of endotracheal tube obstruction due to mucous crust after general anesthesia. A 5-year-old woman with cleft palate was intubated with a 4.5 mm amored tube for general anesthesia. During the surgery, vital signs were within normal limits. In the intensive care unit, she exhibited sign of complete airway obstruction. We exchanged the tube with another tube after failure of suction. The airway obstruction was due to a dried mucous crust attached to the bevel of the endotracheal tube. We should keep in mind the presence of an amored endotracheal tube cannot be regarded as a guarantee of a patent airway.

Nuss 방법에 의한 소아 오목가슴 수술 후 정맥 통증자가조절법을 사용한 Fentanyl 과 Fentanyl-Ketorolac의 진통효과 비교

안기량,서은정,김천숙,강규식,유시현,정진헌,정지원 순천향의학연구소 2006 Journal of Soonchunhyang Medical Science Vol.12 No.2

..

자일리톨 섭취에 따른 Streptococcus mutans의 글루칸 생성관련 유전자 발현 억제효과

김지혜,이영은,안상헌,최연희,남순현,송근배 大韓小兒齒科學會 2009 大韓小兒齒科學會誌 Vol.36 No.4

본 연구에서는 장기적인 자일리톨의 섭취가 Streptococcus mutans의 대표적인 독성인자 중 하나인 글루칸 생성에 미치는 영향을 알아보기 위하여 글루칸 합성효소인 glucosyltansferase의 mRNA 발현을 실시간 역전사 중합효소 연쇄반응을 통해 평가하여 다음과 같은 결과를 얻었다. 1. 24개월 동안 자일리톨껌을 섭취한 군에서 타액 내 Streptococcus mutans의 colony 수는 통계적으로 유의하게 감소하였다(p<0.05). 2. 비수용성 글루칸 합성에 관여하는 유전자인 gtfB, gtfC의 발현은 자일리톨껌을 섭취한 군에서 시간이 지남에 따라 유의 하게 감소하였다(p<0.05). 특히 gtfB의 발현은 12개월과 24개월째 대조군에 비하여 통계적으로 유의하게 낮았고, gtfC의 발현은 24개월째 대조군에 비하여 통계적으로 유의하게 낮았다(p<0.05). 3. 수용성 글루칸 합성에 관여하는 유전자인 gtfD의 발현 역시 자일리톨껌을 섭취한 군에서 시간이 지남에 따라 유의하게 감소하였다(p<0.05). 또한 gtfD의 발현은 12개월과 24개월째 대조군에 비하여 통계적으로 유의하게 낮았다(p<0.05). 이상의 결과들을 종합해 보았을 때, 자일리톨의 섭취는 구강 내 Streptococcus mutans의 글루칸 합성 관련 유전자들의 발현을 억제시킴으로써 Streptococcus mutans의 수적인 감소를 가져오는 것으로 생각된다. Xylitol has the ability to reduce the adherence of Streptococcus mutans(S. mutans), which can make it easier to remove plaque, decrease acid production and inhibit dental caries. There are few reports on the effects of xylitol on the expression of the virulence related genes in S. mutans. This study examined the inhibitory effect of chewing gum containing xylitol on glucan synthesis related gene expression of S. mutans. Participants were voluntarily recruited for a women's oral health prevention program, classified into two groups(a control and a xylitol group), and then followed for 2 years. Twenty salivary samples were randomly selected from each group. Colony count and real-time reverse transcription polymerase chain reaction were used to analyze the characteristics of S. mutans. The following results were obtained: The S. mutans counts decreased steadily in the xylitol group over the study period(p<0.05). The expression of the virulence related genes (gtfB, gtfC and gtfD) was significantly lower in the xylitol group than in the control groups (p<0.05). In conclusion, these results suggest that chewing xylitol gum for a long period of time may reduce the expression of the genes associated with S. mutans virulence, which can result in a decrease growth of S. mutans colonies as a result.

자매 관계에 따른 의복행동

박지은;안홍선;정세희 한양대학교 2012 韓國 生活 科學 硏究 Vol.32 No.1

This research set the big three research-questions in order to find out how sister-relations influence on clothing-consumer sentiment and behavior. The purpose of this study was to analyze the difference of clothing-consumer sentiment and behavior according to Sisters` order of birth; toanalyze sister-relations` influence on the sharing of clothes; to analyze the extent of sisters` sharing clothes and ownership. As a result, when they have older sisters, sister-dependence of decision making is high and attitude about sharing is positive. Also the actual number of sharing clothes is more than the case of having younger sisters. Moreover when intimacy of sisters is high and their body-shapes and styles are similar, they share clothes more. Also sharing extent of outers and accessaries is high according to the less gap between sisters` age. Sharing clothes of sisters is high in T-shirts, accessaries and outer wear and ownership is indefinite when they share clothes a lot. In short, it shows that sister relations and clothing-consumer sentiment and behavior are related.

학교보건교육에서의 매체활용실태 및 영향요인 분석

박은옥,안지영,정혜선,김영임,박정영 韓國學校保健學會 1999 韓國學校保健學會誌 Vol.12 No.2

The objectives of this study are to explain the use of media materials in school health education with other related factors in elementary, middle, and high schools in Korea. The data were collected by questionnaires from June to September in 1988. The number of subjects were 294 school nurses. The PC-SAS program was used for statistical analysis such as percent distribution, chi-squared test, spearman correlation test, and logistic regression. The use of media materials in health education has become extremely common. Unfortunately, much of the early materials were of poor production quality, reflected low levels of interest, and generally did little to enhance health education programming. A recent trend in media materials is a move away from the fact filled production to a more affective, process-oriented approach. There is an obvious need for health educators to use high-quality, polished productions in order to counteract the same levels of quality used by commercial agencies that often promote "unhealthy" lifestyles. Health educators need to be aware of the advantages and disadvantages of the various forms of media. Selecting media materials should be based on more than cost, availability, and personal preference. Selection should be based on the goal of achieving behavioral objectives formulated before the review process begins. The decision to use no media materials rather than something of dubious quality will usually be the right decision. Poor-quality, outdated, or boring materials will usually have a detrimental effect on the presentation. Media materials should be viewed as vehicles to enhance learning, not products that will stand in isolation. Process of materials is an essential part of the educational process. The major results were as follows:1. The elementary schools used the materials more frequently. But the production rate of media materials was not enough. The budget was too small for a wide use of media materials in school health education. These findings suggest that all schools have to increase the budget of health education programs. 2. Computers offer an incredibly diverse set of possibilities for use in health education, ranging from complicated statistical analysis to elementary-school-level health education games. But the use rate of this material was not high. The development of related software is essential. 3. In this study, the most effective materials were films in elementary school and videotapes in middle and high school. Film tends to be a more emotive medium than videotape. The difficulties of media selection involved the small amount of extant educational materials. Media selection is a multifaceted process and should be based on a combination of sound principles. 4. The review of material use following student levels showed that the more the contents were various, the more the use rate was high. 5. Health education videotapes and overhead projectors proved the most plentiful and widest media tools. The information depicted was more likely to be current. As a means to display both text and graphic information, this instructional medium has proven to be both effective and enduring. 6. An analysis of how effective the quality of school nurse and school use of media materials shows a result that is not complete)p=0.1113). But, the budget of health education is a significant variable. The increase of the budget therefore is essential to effective use of media materials. From these results it is recommended that various media materials be developed and be wide used.

심한 척추후측만증 환자의 대퇴골절 복원술을 위한 부위마취 : 증례보고 A case report

김지은,박대용,유시현,강규식,권진형,김천숙,안기량 순천향의학연구소 2004 Journal of Soonchunhyang Medical Science Vol.10 No.2

Kyphoscoliosis is a disease manifested as lateral curvature of spine and accompanying rotation of the vertebrae, resulting in distortion of rib cage. Restrictive lung disease and pulmonary hypertension progressing to cor pulmonale are the major cause of mortality in patients with kyphoscoliosis. We had experienced a successful spinal and caudal epidural anesthesia for the open reduction and internal fixation with plate of fractured femur shaft in two patients with severe kyphosoliosis. We had chosen regional anesthesia as an anesthetic method because of there poor pulmonary function and severe deformities of thoracolumbar spine. We could achieve the adequate anesthetic sensory dermatome level, T_(5) and T_(8), for operation without any significant deterioration of blood pressure and respiration. We recommended that regional anesthesia is a useful anesthetic method for a patients with severe kyphoscoliosis when the operation on hip or lower extremity is required.

수술실 오염도감소를 위한 수술실공조시스템에 대한 연구

김천숙,박은정,강규식,김지은,안기량,권진형,유시현,주영철,권순정 순천향의학연구소 2004 Journal of Soonchunhyang Medical Science Vol.10 No.1

Background: The OR(operating room) should provide an optimum environment that is safe for the patient and the working personnel. The air ventilation system of OR has been studied to decrease the contamination of air. We investigated the flow and contamination of the air in OR at our hospital. Method: Cultures in OR were made and the number of bacteria and fungi were calculated. A two-dimensional model for the cross-section of an operation room is developed for the CFD (computational fluid dynamics) analysis. The characteristics of air flow in the empty operation room and in the occupied operation room are calculated by using a CFD program. Results: The current air ventilation system of our hospital does not deliver the clean air to the operating site efficiently in occupied OR. Conclusions: We suggested a new location of air ventilation system which improves air venting with little increase of the cost of equipment.