• 한국식품과학회지
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• 제16권3호
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• pp.279-284
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• 1984

분유와 분유로 제조된 cheese의 미세구조(微細構造)가 전자 현미경(顯微鏡)에 의해서 관찰되었다. 동결건조 분유는 사과모양을 나타내었다. 동결건조 분유로 제조된 cheese는 전형적인 용융 cheese와 비교하여 표면의 구조가 비교적 편편하고 백색의 균일한 침적물을 나타내었다. 도입 분유 역시 동결건조 분유와 거의 유사한 모앙을 나타내었고, 도입분유로 제조된 cheese는 균일한 분산을 나타내나 표면이 약간 거칠고 caseins matrix와 침적물 사이에 공간이 있다. 시판 분유는 건조중 변성된 것으로 불규칙한 변성 응고물의 모양을 나타내었다. 시판분유로 제조된 cheese의 모양은 불규칙하고 작은 침적물과 세공성이 큰 것으로 나타나 분유의 열변성도는 cheese의 세공성을 증가시키는 것으로 보인다. 변성된 단백질은 변성되지 않은 단백질보다 polyphosphate에 의한 단백질 분산성이 덜 효과적인 것으로 보인다. 분유로 제조한 cheese의 내부구조에서 지방구막과 casein micelle이 전형적인 용융 cheese에 비해 아주 근접해있고 casein micelle이 아주 치밀한 양상을 나타내었다. 분유의 용융 기작도 전형 적인 cheese의 용융과는 다른 것으로 보인다.

• Journal of Yeungnam Medical Science
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• 제35권1호
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• pp.114-120
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• 2018

Tracheal tumors are rare and difficult to diagnose. Moreover, delays in diagnosis are very common because the symptoms are nonspecific. As a result, tracheal tumors are commonly mistreated as chronic obstructive pulmonary disease or bronchial asthma. We report a case of a 49-year-old male who presented with a 3-month history of dyspnea and cough. Chest computed tomography scan showed a $1.5{\times}1.3cm$ homogenous tumor originating from the right lateral wall of the tracheobronchial angle into the tracheal lumen as well as a $0.5{\times}0.4cm$ round nodular lesion at the right upper lobe with multiple mediastinal lymph nodes enlargement. Bronchoscopic findings revealed a broad-based, polypoid lesion nearly obstructing the airway of the right main bronchus. The patient was diagnosed with pleomorphic adenoma which is the most common benign tumor of the salivary glands, but rarely appears in the trachea. Upon surgery, tracheal pleomorphic adenoma and co-existing active pulmonary tuberculoma that had been mistreated as bronchial asthma over 3 months was revealed. Following surgery, the patient underwent anti-tuberculosis treatment. No recurrence has been detected in the 3 years since treatment and the patient is now asymptomatic.

• 농업생명과학연구
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• 제43권2호
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• pp.55-63
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• 2009

본 논문에서는 선행연구와 달리 냉장육 돼지고기와 냉동육 돼지고기에 대한 서로 다른 관세철폐 일정을 명시적으로 고려하여 한?미 FTA가 국내 돼지고기 시장에 미치는 영향을 분석하였다. 국산 돼지고기의 균형가격은 최소 2.69%에서 최대 15.96%까지 감소하고, 물량은 최소 1.35%에서 최대 5.6%까지 감소할 수 있는 것으로 시뮬레이션 된다. 또한 부위별로 보면 관세철폐 이행 이후 돼지고기의 도매가격은 kg당 최소 100원에서 최대 1300원까지 하락할 수 있는 것으로 분석된다. 이러한 분석결과는 한 EU의 협상결과나 DDA 협상 타결로 인한 다른 나라 돼지고기의 수입증가와 같은 돼지고기 시장의 다른 측면과 돼지고기가 타 육류와 가지는 대체관계 등은 고려하지 않은 것이기 때문에, 본 논문의 분석결과는 다른 모든 조건이 일정하다는 가정 하에 미국산 돼지고기의 수입가격이 하락한 상황이 가져오는 효과만을 분석했다는 전제하에 이해되어야 한다.

• Structural Engineering and Mechanics
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• 제19권4호
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• pp.425-440
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• 2005

In this paper, the behavior of a crack between two half-planes of functionally graded materials subjected to arbitrary tractions is resolved using a somewhat different approach, named the Schmidt method. To make the analysis tractable, it is assumed that the Poisson's ratios of the mediums are constants and the shear modulus vary exponentially with coordinate parallel to the crack. By use of the Fourier transform, the problem can be solved with the help of two pairs of dual integral equations in which the unknown variables are the jumps of the displacements across the crack surfaces. To solve the dual integral equations, the jumps of the displacements across the crack surfaces are expanded in a series of Jacobi polynomials. This process is quite different from those adopted in previous works. Numerical examples are provided to show the effect of the crack length and the parameters describing the functionally graded materials upon the stress intensity factor of the crack. It can be shown that the results of the present paper are the same as ones of the same problem that was solved by the singular integral equation method. As a special case, when the material properties are not continuous through the crack line, an approximate solution of the interface crack problem is also given under the assumption that the effect of the crack surface interference very near the crack tips is negligible. It is found that the stress singularities of the present interface crack solution are the same as ones of the ordinary crack in homogenous materials.

• BMB Reports
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• 제54권10호
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• pp.505-515
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• 2021

Human pluripotent stem cells (hPSCs) include human embryonic stem cells (hESCs) derived from blastocysts and human induced pluripotent stem cells (hiPSCs) generated from somatic cell reprogramming. Due to their self-renewal ability and pluripotent differentiation potential, hPSCs serve as an excellent experimental platform for human development, disease modeling, drug screening, and cell therapy. Traditionally, hPSCs were considered to form a homogenous population. However, recent advances in single cell technologies revealed a high degree of variability between individual cells within a hPSC population. Different types of heterogeneity can arise by genetic and epigenetic abnormalities associated with long-term in vitro culture and somatic cell reprogramming. These variations initially appear in a rare population of cells. However, some cancer-related variations can confer growth advantages to the affected cells and alter cellular phenotypes, which raises significant concerns in hPSC applications. In contrast, other types of heterogeneity are related to intrinsic features of hPSCs such as asynchronous cell cycle and spatial asymmetry in cell adhesion. A growing body of evidence suggests that hPSCs exploit the intrinsic heterogeneity to produce multiple lineages during differentiation. This idea offers a new concept of pluripotency with single cell heterogeneity as an integral element. Collectively, single cell heterogeneity is Janus-faced in hPSC function and application. Harmful heterogeneity has to be minimized by improving culture conditions and screening methods. However, other heterogeneity that is integral for pluripotency can be utilized to control hPSC proliferation and differentiation.

• 대한치과교정학회지
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• 제51권5호
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• pp.355-362
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• 2021

Objective: This study aimed to establish the prevalence and patterns of nonsyndromic tooth agenesis in patients referred to a tertiary health care facility. Methods: The intraoral records and panoramic radiographs of 9,874 patients aged 12-22 years were evaluated. The study group included 716 patients (371 male, 345 female) with non-syndromic agenesis of at least one tooth (except the third molars). The study data were assessed using descriptive statistics, chi-square test, and Mann-Whitney U test, while patterns were evaluated using a tooth agenesis code (TAC) tool. Results: A total of 1,627 congenitally missing teeth, were found in patients with non-syndromic tooth agenesis, with an average of 2.27 missing teeth per patient. The prevalence of tooth agenesis was 7.25%, and the most commonly missing teeth were the left mandibular second premolars (10.17%). The age group comparison revealed no significant difference in the median number of missing teeth per patient according to the cutoff values for ages between 12 and 22 years. When the missing teeth were examined separately according to quadrants, 114 different tooth agenesis patterns (upper right quadrant = 28, upper left quadrant = 27, lower left quadrant = 31, and lower right quadrant = 28) were identified, and 81 of these patterns appeared only once. Conclusions: This study highlights the benefits of applying the TAC tool in a large sample population. The application of the TAC tool in such studies will enable the development of template treatment plans by determining homogenous patterns of tooth agenesis in certain populations.

• Steel and Composite Structures
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• 제32권2호
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• pp.157-171
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• 2019

In this research, the dynamic instability region (DIR) of the sandwich nano-beams are investigated based on nonlocal strain gradient elasticity theory (NSGET) and various higher order shear deformation beam theories (HSDBTs). The sandwich piezoelectric nano-beam is including a homogenous core and face-sheets reinforced with functionally graded (FG) carbon nanotubes (CNTs). In present study, three patterns of CNTs are employed in order to reinforce the top and bottom face-sheets of the beam. In addition, different higher-order shear deformation beam theories such as trigonometric shear deformation beam theory (TSDBT), exponential shear deformation beam theory (ESDBT), hyperbolic shear deformation beam theory (HSDBT), and Aydogdu shear deformation beam theory (ASDBT) are considered to extract the governing equations for different boundary conditions. The beam is subjected to thermal and electrical loads while is resting on Visco-Pasternak foundation. Hamilton principle is used to derive the governing equations of motion based on various shear deformation theories. In order to analysis of the dynamic instability behaviors, the linear governing equations of motion are solved using differential quadrature method (DQM). After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as various shear deformation theories, nonlocal parameter, strain gradient parameter, the volume fraction of the CNTs, various distributions of the CNTs, different boundary conditions, dimensionless geometric parameters, Visco-Pasternak foundation parameters, applied voltage and temperature change on the dynamic instability characteristics of sandwich piezoelectric nano-beam.

• Physical Therapy Rehabilitation Science
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• 제8권3호
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• pp.125-133
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• 2019

Objective: To compare the postural control between non-specific chronic low back pain (NSCLBP) subgroups and healthy people during dynamic balance performance using a modified Star Excursion Balance Test (mSEBT). Design: Cross-sectional study. Methods: Eighteen NSCLBP subjects (9 active extension pattern [AEP], 9 flexion pattern [FP]), and 10 healthy controls were enrolled in this study. All subjects performed mSEBT on their dominant leg on a force plate. Normalized reach distance and balance parameters, including the center of pressure (COP) displacement and velocity, were recorded. Results: There were significant differences in mean reach distances in both posterolateral and posteromedial (PM) reach directions between AEP and healthy subjects (p<0.001) and between FP and healthy subjects (p<0.001). However, there were no significant differences among the three groups in the anterior reach direction. Also, the results showed no significant differences in mean COP variables (velocity and displacement) between pooled NSCLBP and healthy subjects. However, the subjects were reclassified into AEP, FP and healthy groups and the results showed a significant difference in mean COP velocity in the PM direction between AEP and FP subjects (p=0.048), and between AEP and healthy subjects (p=0.024). Conclusions: The findings in this study highlight the heterogeneity of the individuals with NSCLBP and the importance of identifying the homogenous subgroups. Individuals with AEP and FP experience deficits in dynamic postural control compared to healthy controls. In addition, the findings of this study support the concept of the Multidimensional Classification System.

• Nuclear Engineering and Technology
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• 제50권7호
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• pp.1138-1147
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• 2018

Delayed hydride cracking (DHC) is an important failure mechanism for Zircaloy tubes in the demanding environment of nuclear reactors. The threshold stress intensity factor, $K_{IH}$, and critical hydride length, $l_C$, are important parameters to evaluate DHC. Theoretical models of them are developed for Zircaloy tubes undergoing non-homogenous temperature loading, with new stress distributions ahead of the crack tip and thermal stresses involved. A new stress distribution in the plastic zone ahead of the crack tip is proposed according to the fracture mechanics theory of second-order estimate of plastic zone size. The developed models with fewer fitting parameters are validated with the experimental results for $K_{IH}$ and $l_C$. The research results for radial cracking cases indicate that a better agreement for $K_{IH}$ can be achieved; the negative axial thermal stresses can lessen $K_{IH}$ and enlarge the critical hydride length, so its effect should be considered in the safety evaluation and constraint design for fuel rods; the critical hydride length $l_C$ changes slightly in a certain range of stress intensity factors, which interprets the phenomenon that the DHC velocity varies slowly in the steady crack growth stage. Besides, the sensitivity analysis of model parameters demonstrates that an increase in yield strength of zircaloy will result in a decrease in the critical hydride length $l_C$, and $K_{IH}$ will firstly decrease and then have a trend to increase with the yield strength of Zircaloy; higher fracture strength of hydrided zircaloy will lead to very high values of threshold stress intensity factor and critical hydride length at higher temperatures, which might be the main mechanism of crack arrest for some Zircaloy materials.

• Asian-Australasian Journal of Animal Sciences
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• 제32권7호
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• pp.977-987
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• 2019

Objective: The use of tannin extract and other phytochemicals as dietary additives in ruminants is becoming more popular due to their wide biological actions such as in methane mitigation, bypass of dietary protein, intestinal nematode control, among other uses. Unfortunately, some have strong astringency, low stability and bioavailability, and negatively affecting dry matter intake and digestibility. To circumvent these drawbacks, an effective delivery system may offer a promising approach to administer these extracts to the site where they are required. The objectives of this study were to encapsulate acacia tannin extract (ATE) with native starch and maltodextrin-gum arabic and to test the effect of encapsulation parameters on encapsulation efficiency, yield and morphology of the microparticles obtained as well as the effect on rumen in vitro gas production. Methods: The ATE was encapsulated with the wall materials, and the morphological features of freeze-dried microparticles were evaluated by scanning electron microscopy. The in vitro release pattern of microparticles in acetate buffer, simulating the rumen, and its effect on in vitro gas production was evaluated. Results: The morphological features revealed that maltodextrin/gum-arabic microparticles were irregular shaped, glossy and smaller, compared with those encapsulated with native starch, which were bigger, and more homogenous. Maltodextrin-gum arabic could be used up to 30% loading concentration compared with starch, which could not hold the core material beyond 15% loading capacity. Encapsulation efficiency ranged from $27.7%{\pm}6.4%$ to $48.8%{\pm}5.5%$ in starch and $56.1%{\pm}4.9%$ to $64.8%{\pm}2.8%$ in maltodextrin-gum arabic microparticles. Only a slight reduction in methane emission was recorded in encapsulated microparticles when compared with the samples containing only wall materials. Conclusion: Both encapsulated products exhibited the burst release pattern under the pH conditions and methane reduction associated with tannin was marginal. This is attributable to small loading percentages and therefore, other wall materials or encapsulation methods should be investigated.