• Geomechanics and Engineering
• /
• 제18권1호
• /
• pp.85-96
• /
• 2019

A free vibration analysis and wave propagation of triclinic and orthotropic plate has been presented in this work using an efficient quasi 3D shear deformation theory. The novelty of this paper is to introducing this theory to minimize the number of unknowns which is three; instead four in other researches, to studying bulk waves in anisotropic plates, other than it can model plates with great thickness ratio, also. Another advantage of this theory is to permits us to show the effect of both bending and shear components and this is carried out by dividing the transverse displacement into the bending and shear parts. Hamilton's equations are a very potent formulation of the equations of analytic mechanics; it is used for the development of wave propagation equations in the anisotropic plates. The analytical dispersion relationship of this type of plate is obtained by solving an eigenvalue problem. The accuracy of the present model is verified by confronting our results with those available in open literature for anisotropic plates. Moreover Numerical examples are given to show the effects of wave number and thickness on free vibration and wave propagation in anisotropic plates.

• Steel and Composite Structures
• /
• 제44권2호
• /
• pp.155-169
• /
• 2022

In the present paper an analytical model was developed to study the non-linear vibrations of Functionally Graded Carbon Nanotube (FG-CNT) reinforced doubly-curved shallow shells using the Multiple Scales Method (MSM). The nonlinear partial differential equations of motion are based on the FGM shallow shell hypothesis, the non-linear geometric Von-Karman relationships, and the Galerkin method to reduce the partial differential equations associated with simply supported boundary conditions. The novelty of the present model is the simultaneous prediction of the natural frequencies and their mode shapes versus different curvatures (cylindrical, spherical, conical, and plate) and the different types of FG-CNTs. In addition to combining the vibration analysis with optimization algorithms based on the genetic algorithm, a design optimization methode was developed to maximize the natural frequencies. By considering the expression of the non-dimensional frequency as an objective optimization function, a genetic algorithm program was developed by valuing the mechanical properties, the geometric properties and the FG-CNT configuration of shallow double curvature shells. The results obtained show that the curvature, the volume fraction and the types of NTC distribution have considerable effects on the variation of the Dimensionless Fundamental Linear Frequency (DFLF). The frequency response of the shallow shells of the FG-CNTRC showed two types of nonlinear hardening and softening which are strongly influenced by the change in the fundamental vibration mode. In GA optimization, the mechanical properties and geometric properties in the transverse direction, the volume fraction, and types of distribution of CNTs have a considerable effect on the fundamental frequencies of shallow double-curvature shells. Where the difference between optimized and not optimized DFLF can reach 13.26%.

• 한국엔터테인먼트산업학회논문지
• /
• 제13권8호
• /
• pp.281-290
• /
• 2019

본 연구는 뮤지컬 광고커뮤니케이션이 뮤지컬 관객의 관람태도와 관람의도 및 재 관람의도에 어떠한 영향을 미치는지 알아보고자 하였다. 연구 결과 첫째, 뮤지컬 광고커뮤니케이션의 뮤지컬 공연 관람태도에 대한 영향을 알아본 결과, 광고커뮤니케이션의 뮤지컬 공연 브랜드 친숙도와 광고 노블티는 뮤지컬 공연 관람태도에 정(+)의 영향을 미치는 것으로 나타났다. 반면 메시지 복잡성은 뮤지컬 공연 관람태도에 유의한 영향을 미치지 않는 것으로 나타났다. 둘째, 뮤지컬 공연 관람태도는 뮤지컬 공연 관람의도에 정(+)의 영향을 미치는 것으로 나타났다. 셋째, 뮤지컬 공연 관람의도는 뮤지컬 공연 재 관람의도에 정(+)의 영향을 미치는 것으로 나타났다. 본 연구결과는 향후 뮤지컬 콘텐츠의 관객에 대한 커뮤니케이션 효과 제고를 위한 유용한 시사점과 함께 커뮤니케이션 방법과 전략을 제시할 수 있을 것으로 기대된다.

• Anatomy and Cell Biology
• /
• 제57권1호
• /
• pp.119-128
• /
• 2024

Glucocorticoids play a physiologic role in the adult male reproductive functions, modulating gonadal steroid synthesis and spermatogenesis, through the glucocorticoid receptor (GR). The expression of GR has been described in several key testicular cell types, including somatic cells and early germ cell populations. Nothing is known on GR in human spermatozoa. Herein, we explored the GR expression and its possible role in normal and testicular varicocele semen samples from volunteer donors. After semen parameter evaluation by macro- and microscopic analysis, samples were centrifuged; then spermatozoa and culture media were recovered for further investigations. By western blotting and immunofluorescence analyses we evidenced for the first time in spermatozoa the presence of GR-D3 isoform which was reduced in sperm from varicocele patients. By treating sperm with the synthetic glucocorticoid dexamethasone (DEXA), we found that survival, motility, capacitation, and acrosome reaction were increased in both healthy and varicocele samples. GR involvement in mediating DEXA effects, was confirmed by using the GR inhibitor mifepristone (M2F). Worthy, we also discovered that sperm secretes different cortisol amounts depending on its physio-pathological status, suggesting a defence mechanism to escape the immune system attach in the female genital tract thus maintaining the immune-privilege as in the testis. Collectively, our data suggests a role for glucocorticoids in determining semen quality and function, as well as in participating on sperm immune defensive mechanisms. The novelty of this study may be beneficial and needs to take into account in artificial insemination/drug discovery aimed to enhancing sperm quality.

• 벤처창업연구
• /
• 제9권5호
• /
• pp.103-114
• /
• 2014

기업가적 지향성은 신생기업의 사업 성공을 위해 필수적으로 요구되는 성향이라고 알려져 있다. 기업가적 지향성은 시장기회를 포착하는데 유용하기 때문에 자원이 부족하고 조직 성장을 위한 수단들을 모색하기 쉽지 않은 중소 벤처기업들이 고려할 수 있는 좋은 대안으로 설명되고 있다. 그렇지만 다양한 경영성과를 대상으로 기업가적 지향성의 성과 효과를 심도 있게 비교하고 있는 실증연구들은 제한된다. 이에 본 연구는 기업가적 지향성과 경영성과간의 관계를 파악하는 기존 실증연구들을 검토하여 그 동안 논의가 제한적이었던 두 가지 이슈에 초점을 맞추어 기업가적 지향성의 성과 효과를 재검토하였다. 첫째, 기업가적 지향성의 선형적인 효과뿐만 아니라 비선형적인 효과를 파악함으로써 기업가적 지향성의 성과 효과를 다각도로 검토하였다. 둘째, 기업가적 지향성을 측정하는 방식을 달리 하더라도 분석결과가 일관되게 나타나는 지를 검토하였다. 한국의 1,497개 중소 벤처기업을 대상으로 한 논문의 분석결과, 매출액 증가율과 같은 재무적 성과를 경영성과로 한 기업가적 지향성의 비선형 효과는 통계적으로 유의미하지 않은 것으로 나타난 반면, 기술개발 및 제품개발 성과와 같은 혁신성과에 대한 기업가적 지향성의 비선형 효과는 통계적으로 유의미한 것으로 나타났다. 그리고 이와 같은 기업가적 지향성과 경영성과간의 관계 패턴은 기업가적 지향성의 측정 방법을 달리하더라도 유사하게 나타났다. 이러한 분석결과에 근거하여 본 연구의 이론적 함의, 한계 및 미래의 연구 방향에 대해 기술하였다.

• 마케팅과학연구
• /
• 제16권2호
• /
• pp.109-132
• /
• 2006

본 연구는 기업 내 신제품 개발 조직의 내적 특성에 초점을 투고, 심리적 임파워먼트, 조직기억이 신제품 창조성의 매개효과 분석, 그리고 시장 불확실성의 조절효과 분석을 주목적으로 한다. 이러한 연구 목적을 달성하기 위하여 신제품 성과에 영향을 미치는 선행요인으로 신제품 개발 조직의 임파워먼트, 조직기억, 신제품 창조성을 설정하고, 조절변수로서 시장 불확실성을 고려하여 연구모형을 제시하였으며, 이들 각 요인들 간의 관계를 국내 식음료 제조업에 속한 121개 기업을 대상으로 설문조사를 통한 실증분석을 수행하였다. 공변량구조분석을 통한 신제품 성과와 선행요인간의 관계에 관한 실증분석 결과, 임파워먼트와 조직기억은 신제품 창조성에 유의한 영향을 미치는 것으로 나타났다. 신제품 창조성의 새로움 차원은 신제품 성과에 유의적인 영향을 미쳤지만, 의미성 차원은 유의적이지 않았다. 그리고 시장불확실성 조절효과 존재여부에 대한 검증에서는 경쟁불확실성만이 신제품 창조성의 의미성 차원과 신제품 성과 간의 관계에서 유의한 조절효과를 가지는 것으로 나타났다.

• 한국환경생태학회지
• /
• 제30권3호
• /
• pp.406-414
• /
• 2016

본 연구는 치악산국립공원 구룡 오토캠핑장 이용객을 대상으로 설문조사를 실시하여(N =165), 누가 그리고 왜 오토캠핑을 휴양활동으로 선택하였는지 분석하였다. 설문조사 결과 오토캠핑장 주이용객은 교육 수준(전문대졸 이상 88%)과 소득 수준(가구 총소득 3,000만 원 이상 87%)이 높은 30~40대(85%)의 직장인(60%)이었다. 또한 오토캠핑 이용객은 가족 단위 이용객(82%)이 대부분이었고 오토캠핑장을 년 10회 이상 이용한다는 응답자 비율이 24%에 달해 오토캠핑이 주요 여가 활동인 경우도 많았다. 5년 이상 오토캠핑 경력이 있는 응답자는 18%에 불과해 오토캠핑은 최근 수요가 증가하고 있는 휴양 활동이라는 것을 알 수 있었다. 오토캠핑의 19개 장점에 대한 응답자들의 동의수준 데이터를 요인분석으로 분석한 결과, '자연접촉으로 기분전환(요인 1)', '새로움과 성취감(요인 2)', '편리성(요인 3)', '즐거움(즐길거리)(요인 4)'의 4가지 오토캠핑 선택 요인을 추출하였다. 4가지 오토캠핑 선택 요인이 오토캠핑장 이용 만족도(연간 오토캠핑장 방문 횟수)에 미치는 영향을 토빗(Tobit) 회귀분석으로 분석한 결과 '자연접촉으로 기본전환'의 영향이 가장 크고, '편리함', '즐거움' 순으로 영향을 주었지만 '즐거움'은 오토캠핑장 이용 만족도에 통계적으로 유의미한 영향을 주지 않았다. 이는 오토캠핑장 설계 운영시 편의시설이나 놀이시설을 늘리기 보다는 주변의 자연을 훼손하지 않고 유지하도록 할 필요가 있음을 시사해 주는 결과이다.

• 대한치과마취과학회지
• /
• 제14권1호
• /
• pp.29-39
• /
• 2014

Background: Dental phobia or anxiety of patients is the serious impediment to appropriate and effective dental treatment. Sedative technique helps to mitigate patients' fear and anxiety thus make them more cooperative and familiar to dental practices. With increasing attention to sedative dentistry in dentists, educational requirements and technical qualification also become stricter but actual survey on recent sedative dentistry has not been reported yet. Especially there is insufficient study reporting the survey of sedative dentistry subjected to Korean adults. In this paper, we conducted a survey study on the actual condition and practice related to sedation with a questionnaire to dentists in South Korea. Methods: The survey was done for members of The Korean Dental Society of Anesthesiology (KDSA), who had great interest in sedation and for whom survey-by-mail was convenient. 472 members of The KDSA having dental license and solid address and contact information were subjected to the survey by sending them survey questions about their sedative techniques and knowledge. In order to increase the response rate, small gifts were presented to those who accurately responded to the survey questions and text messages and phone calls were made to encourage their participation. We collected their responses over two months and examined the returned surveys. Statistical analysis was performed using IBM SPSS Statistics 21 for each question. Results: Out of 472 dentists, 181 responded (38.4% response rate). 63.0% (114 dentists; 77 male and 37 female) of respondents had experience on sedative technique and their average age was $39.8{\pm}7.6$ year. 74 of them were private practitioners, 17 of them were professors (14.9%), 11 of them were dentists-in-service (9.6%), 11 of them were residents (specialist training) (9.6%) and 1 of them was military doctors (0.9%). There were 89 dentists (78.1%) who were specialists or receiving trainings to be specialist, most of whom were pediatric dentists (55, 48.2%) and oral surgeon (31, 27.2%). The most popular route for drug medications was orderly oral, inhalational, intravenous medication. Combination of oral and inhalational medications or single use of intravenous medication was the most common. The most preferred sedative drug was pocral in oral sedation and midazolam in intravenous sedation. 48.2% of practitioners responded that they experienced side effects and emergency situations. Airway obstruction was the most frequent. Conclusions: Results from the survey show that the protocol and system for sedative dentistry have been improved compared to the past. Nevertheless, quality of emergency protocol, monitoring devices and preparation of sedative drugs was still insufficient to achieve safe sedative procedure. This study acquires novelty since actual survey on recent sedative dentistry for adult patients has not been reported yet.

• Journal of Microbiology and Biotechnology
• /
• 제19권9호
• /
• pp.987-996
• /
• 2009

Aspergillus niger GH1 previously isolated and identified by our group as a wild tannase producer was grown under solid-state (SSC) and submerged culture (SmC) conditions to select the enzyme production system. For tannase purification, extracellular tannase was produced under SSC using polyurethane foam as the inert support. Tannase was purified to apparent homogeneity by ultrafiltration, anion-exchange chromatography, and gel filtration that led to a purified enzyme with a specific activity of 238.14 IU/mg protein with a final yield of 0.3% and a purification fold of 46. Three bands were found on the SDS-PAG with molecular masses of 50, 75, and 100 kDa. PI of 3.5 and 7.1% N-glycosylation were noted. Temperature and pH optima were 600e and 6.0 [methyl 3,4,5-trihydroxybenzoate (MTB) as substrate], respectively. Tannase was found with a $K_M$ value of $0.41{\times}10^{-4}M$ and the value of $V_{max}$ was $11.03{\mu}$moL/min at $60^{\circ}C$ for MTB. Effects of several metal salts, solvents, surfactants, and typical enzyme inhibitors on tannase activity were evaluated to establish the novelty of the enzyme. Finally, the tannase from A. niger GH1 was significantly inhibited by PMSF (phenylmethylsulfonyl fluoride), and therefore, it is possible to consider the presence of a serine or cysteine residue in the catalytic site.

• Biomolecules & Therapeutics
• /
• 제25권4호
• /
• pp.374-382
• /
• 2017

Autism spectrum disorder (ASD) remains unexplained and untreated despite the high attention of research in recent years. Aside from its various characteristics is the baffling male preponderance over the female population. Using a validated animal model of ASD which is the telomerase reverse transcriptase overexpressing mice (TERT-tg), we conducted ASD-related behavioral assessments and protein expression experiments to mark the difference between male and females of this animal model. After statistically analyzing the results, we found significant effects of TERT overexpression in sociability, social novelty preference, anxiety, nest building, and electroseizure threshold in the males but not their female littermates. Along these differences are the male-specific increased expressions of postsynaptic proteins which are the NMDA and AMPA receptors in the prefrontal cortex. The vGluT1 presynaptic proteins, but not GAD, were upregulated in both sexes of TERT-tg mice, although it is more significantly pronounced in the male group. Here, we confirmed that the behavioral effect of TERT overexpression in mice was male-specific, suggesting that the aberration of this gene and its downstream pathways preferentially affect the functional development of the male brain, consistent with the male preponderance in ASD.