• 대한기계학회논문집B
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• 제31권3호
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• pp.209-216
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• 2007

Bacterial chemotaxis is essential to the study of structure and function of bacteria. Although many studies have accumulated the knowledge about chemotaxis in the past, the motion of a single bacterium has not been studied much yet. In this study, we have developed a device microfabricated by soft lithography and consisting of microfluidic channels. The microfluidic assay generates a concentration gradient of chemoattractant linearly in the main channel by only diffusion of the chemicals. Bacteria are injected into the main channel in a single row by hydrodynamic focusing technique. We measured the velocity of bacteria in response to a given concentration gradient of chemoattractant using the microfludic assay, optical systems with CCD camera and simple PTV (Particle Tracking Velocimetry) algorithm. The advantage of this assay and experiment is to measure the velocity of a single bacterium and to quantify the degree of chemotaxis by statistically analyzing the velocity at the same time. Specifically, we measured and analyzed the motility of Escherichia coli strain RP437 in response to various concentration gradients of L-aspartate statistically and quantitatively by using this microfluidic assay. We obtained the probability density of the velocity while RP437 cells are swimming and tumbling in the presence of the linear concentration gradient of L-aspartate, and quantified the degree of chemotaxis by analyzing the probability density.

• 한국가금학회지
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• 제31권1호
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• pp.45-54
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• 2004

The consumption of poultry meat (chicken and turkey) grew the most during the past few decades due to several contributing factors such as low price, product research and development, favorable meat characteristics, responsive to consumer needs, vertical integration and industry consolidation, new processing equipments and technology, and aggressive marketing. The major processing technologies developed and used in chicken processing include forming/restructuring, tumbling, curing, smoking, massaging, injection, marination, emulsifying, breading, battering, shredding, dicing, and individual quick freezing. These processing technologies were applied to various parts of chicken including whole carcass. Product developments using breast, thigh, and mechanically separated chicken meat greatly increased the utilization of poultry meat. Chicken breast became the symbol of healthy food, which made chicken meat as the most frequent menu items in restaurants. However, the use of and product development for dark meat, which includes thigh, drum, and chicken wings were rather limited due to comparatively high fat content in dark meat. Majority of chicken are currently sold as further processed ready-to-cook or ready-to-eat forms. Major quality issues in chicken meat include pink color problems in uncured cooked breast, lipid oxidation and off-flavor, tenderness PSE breast, and food safety. Research and development to ensure the safety and quality of raw and cooked chicken meat using new processing technologies will be the major issues in the future as they are now. Especially, the application of irradiation in raw and cooked chicken meat products will be increased dramatically within next 5 years. The market share of ready-to-eat cooked meat products will be increased. More portion controlled finished products, dark meat products, and organic and ethnic products with various packaging approaches will also be introduced.

• 한국식품과학회지
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• 제9권1호
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• pp.61-67
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• 1977

고추씨를 분리(分離)하는 방법(方法)으로 자유낙하(自由落下), 상하진탕, 회전사(回轉篩)를 이용(利用)하는 방법(方法)과 그 기구(機構)에 관(關)하여 연구(硏究)한 결과(結果) 씨의 분리(分離)는 고추에 가(加)해 주는 충격량(衝擊量)으로 설명(說明)할 수있었으며, 이를 운동량(運動量)의 크기로 분석(分析)하였다. 씨의 분리(分離)에 기여(寄與)하는 운동량(運動量)의 영향은 속도(速度)를 얻은 방법(方法)에 따라 상이(相異)하였다. 한편 동일속도하(同一速度下)에서 운동량(運動量)의 씨분리효과(分離？果)를 산출(算出)하였으며, 자유낙하(自由落下), 상하진탕 및 회전사방법(回轉篩方法)에서 각각(各各) $2.50{\times}10^{-6}$, $2.09{\times}10^{-6}$과 $3.94{\times}10^{-8}$의 값을 보였다. 고추씨의 분리속도(分離速度)의 변화율(變化率)은 고추의 건조속도(乾燥速度)의 변화율(變化率)과 유사한 경시적(經時的) 변화양상(變化樣相)을 갖고 있었다.

• 한국의류산업학회지
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• 제21권4호
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• pp.497-508
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• 2019

Snowboarder accidents at ski resorts are increasing; therefore, it is essential to wear protective wrist, hip and knee protectors when snowboarding. However, most studies focus on the improvement of gear or expansion of safety facilities with few studies on protectors that directly safeguard the body from accidents caused by tumbling. Protectors currently on the market do not properly consider the needs of the users. Therefore, this study investigates the reality of usage and satisfaction rate of those that use snowboarding protectors along with factors deemed important upon wearing them to provide the grounds for the development of comfortable protectors. Subjects were 1,058 adults in their 20s to 40s. First, a survey was conducted regarding demographic traits as well as the wearing and purchasing of protectors. Second, 325 people that purchased and wore protectors were investigated in regards to the wearing satisfaction rate of current commercial protectors. The results showed that 86% of the 1,058 subjects wore protectors; knee protectors (72%), hip protectors (57%) and wrist protectors (38%). Important factors upon purchasing and wearing satisfaction were studied according to demographic traits, snowboarding experience, and number of snowboard rides for one season. As a result, the damage rate increased along with the number of snowboard rides for one season. Important factors considered when purchasing varied significantly according to sex, age, snowboarding experience, and favored slopes. The results of this study will help in the design of comfortable protectors for snowboarders.

• 한국식품저장유통학회지
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• 제31권3호
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• pp.423-432
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• 2024

본 연구에서는 육가공 산업의 필수 공정인 냉동육 해동 시 발생하는 식육의 품질 저하를 최소화하기 위하여 진공 텀블링 해동 방식을 적용하고자 산업용 국산 임펠러-진공 텀블러(DVT, 6 ton)를 고안하고 이를 이용하여 해동한 냉동 돈육의 품질 특성을 현재 상업적으로 이용하는 자연해동(NTA)과 수입산 진공 텀블링 해동(IVT) 특성과 비교 분석하였다. 냉동 돈육(앞다리)의 자연해동 시간은 4,200분인데 반하여 DVT 해동은 165분이 소요되어 냉동 돈육 해동시간이 약 25배 단축되었다. 해동 시 돈육의 드립감량은 자연해동 2.08%에 비하여 DVT 해동은 0.85%로 낮아져 높은 해동 수율(99.2%)을 얻을 수 있었다. 자연 해동육에서 대장균군이 0.10±0.17 log CFU/g 수준으로 검출된데 반하여 DVT 해동육의 pH는 5.92, 총균수 1.96±0.01 log CFU/g, 대장균군 불검출로 높은 신선도를 보였다. 또한, DVT 해동육의 지방산패도(TBARS) 0.31±0.01 MDA mg/kg와 단백질변패도(VBN) 5.67±1.98 mg%를 보여 자연해동 돈육(각각 0.42±0.01 MDA mg/kg와 6.86±0.00 mg%)에 비해 지방과 단백질 변패도를 유의적으로 낮출 수 있는 것으로 나타났다. DVT 해동육의 보수력은 97.50±0.90%로 자연해동육(95.24±0.03%)에 비해 유의적으로 높았다. 자연해동(NTA) 후 조리한 돈육은 경도 212.03±0.02 N과 씹힘성 885.36±0.80이 진공 텀블링(DVT, IVT) 해동육에 비하여 각각 6.1배와 4.7배 높게 나타나 진공 텀블링 해동이 부드러운 조직감을 갖는 식육을 생산할 수 있는 것으로 나타났다. 해동육과 이를 가열조리한 돈육의 미세구조(SEM)를 관찰한 결과, 진공 텀블링 해동(DVT, IVT) 시료에서 근원섬유의 손상이 적어 섬유배열과 간격이 촘촘한 구조를 나타냈다. 본 연구에서 국내 최초로 고안한 산업용 대용량 진공텀블러는 해동 시 근육 조직의 손상을 최소화하여 보수력을 높이고, 드립감량을 감소시켜 부드러운 조직감과 함께 생산 수율을 높일 수 있을 뿐만 아니라 미생물학적 및 이화학적 변패도를 최소화할 수 있어 고품질의 육제품 생산에 활용될 수 있을 것으로 보인다. 또한, 본 장치는 수입산 진공텀블러와 비교해 우수한 품질의 해동육을 생산할 수 있어 본 연구자료를 이용한 국산 기술 자립화, 제품 품질 개선 및 수율 향상 등 육가공 산업 발전에 기여할 수 있을 것이라 사료된다.

• 대한디지털의료영상학회논문지
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• 제15권2호
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• pp.63-68
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• 2013

Purpose : The relaxation times of tissue in MRI depend on strength of magnetic field, morphology of nuclear, viscosity, size of molecules and temperature. This study intended to analyze quantitatively that materials' temperatures have effects on T1 and T2 relaxation times without changing of other conditions. Materials and Methods : The equipment was used MAGNETOM SKYRA of 3.0T(SIEMENS, Erlagen, Germany), 32 channel spine coil and Gd-DTPA water concentration phantom. To find out T1 relaxation time, Inversion Recovery Spin Echo sequences were used at 50, 400, 1100, 2500 ms of TI. To find out T2 relaxation time, Multi Echo Spin Echo sequences were used at 30, 60, 90, 120, 150, 180, 210, 240, 270 ms of TE. This experiment was scanned with 5 steps from 25 to $45^{\circ}C$. next, using MRmap(Messroghli, BMC Medical Imaging, 2012) T1 and T2 relaxation times were mapped. on the Piview STAR v5.0(Infinitt, Seoul, Korea) 5 steps were measured as the same ROI, and then mean values were calculated. Correlation between the temperatures and relaxation times were analyzed by SPSS(version 17.0, Chicago, IL, USA). Results : According to increase of temperatures, T1 relaxation times were $214.39{\pm}0.25$, $236.02{\pm}0.87$, $267.47{\pm}0.48$, $299.44{\pm}0.64$, $330.19{\pm}1.72$ ms. T2 relaxation times were $180.17{\pm}0.27$, $197.17{\pm}0.44$, $217.92{\pm}0.39$, $239.89{\pm}0.53$, $257.40{\pm}1.77$ ms. With the correlation analysis, the correlation coefficients of T1 and T2 relaxation times were statistically significant at 0.998 and 0.999 (p< 0.05). Conclusion : T1 and T2 relaxation times are increased as temperature of tissue goes up. In conclusion, we suggest to recognize errors of relaxation time caused local temperature's differences, and consider external factors as well in the quantitative analysis of relaxation time or clinical tests.

• Investigative Magnetic Resonance Imaging
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• 제3권2호
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• pp.159-166
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• 1999

Purpose : To evaluate the effect of rotational correlation time (${\tau}_R$) and the possible related changes of other parameters, ${\tau}_M,{\;}{\tau}_S,{\;}and{\;}(\tau}_V$ of gadolinium (Gd) chelate on T1 relaxation enhancement in two pool model. Materials and Methods : The NMRD (Nuclear Magnetic Relaxation Dispersion) profiles were simulated from 0.02 MHz to 800 MHz proton Larmor frequency for different values of rotational correlation times based on Solomon-Bloembergen equation for inner-sphere relaxation enhancement. To include both unbound pool (pool A) and bound pool (pool B), the relaxivity was divided by contribution from unbound pool and bound pool. The rotational correlation time for pool A was fixed at the value of 0.1 ns, which is a typical value for low molecular weight complexes such as Gd-DTPA in solution and ${\tau}_R$ for pool B was changed from 0.1 ns to 20 ns to allow the slower rotation by binding to macromolecule. The fractional factor of was also adjusted from 0 to 1.0 to simulate different binding ratios to macromolecule. Since the binding of Gd-chelate to macromolecule cab alter the electronic environment of Gd ion and also the degree of bulk water access to hydration site of Gd-chelate, the effects of these parameters were also included. Results : The result shows that low field profiles, ranged from 0.02 to 40 MHz, and dominated by contribution from bound pool, which is bound to macromolecule regardless of binding ratios. In addition, as more Gd-chelate bound to macromolecule, sharp increase of relaxivity at higher field occurs. The NMRD profiles for different values of ${\tau}_S$ show the enormous increase of low field profile whereas relaxivity at high field is not affected by ${\tau}_S$. On the other hand, the change in ${\tau}$V does not affect low field profile but strongly in fluences on both inflection fie이 and the maximum relaxivity value. The results shows a fluences on both inflection field and the maximum relaxivity value. The results shows a parabolic dependence of relaxivity on ${\tau}_M$. Conclusion : Binding of Gd-chelate to a macromolecule causes slower rotational tumbling of Gd-chelate and would result in relaxation enhancement, especially in clinical imaging field. However, binding to macromolecule can change water enchange rate (${\tau}_M$) and electronic relaxation ($T_le$) vis structural deformation of electron environment and the access of bulk water to hydration site of metal-chelate. The clinical utilities of Gd-chelate bound to macromolecule are the less dose requirement, the tissue specificity, and the better perfusion and intravascular agents.

• 한국콘텐츠학회논문지
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• 제9권7호
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• pp.218-224
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• 2009

이 연구는 악안면외상경험과 측두하악장애 유병상태와의 관련성을 조사하여 측두하악장애의 예방과 치료계획에 도움을 주고자 울산광역시에 소재한 C보건대학 학생 370명을 대상으로 설문조사를 실시하였다. 수집된 자료는 SPSS 프로그램을 이용하여 분석하여 다음과 같은 결론을 얻었다. 1. 측두하악관절잡음 유병률은 남학생 25.7%, 여학생 22.7%로 남학생이 측두관절잡음 발생이 높았으나(p<0.01), 학년별로는 유의한 차이를 보이지 않았다. 2. 측두하악동통 유병률은 여학생이 높게 나타났다. 3. 개구장애 유병률은 여학생 10.8%, 남학생 7.0%로 여학생이 개구장애 발생이 약간 높게 나타났다. 4 측두하악장애로 인한 치료 경험은 남학생 6.5%, 여학생 4.3%로 남학생이 측두하악장애 치료경험률이 높게 나타났다(p<0.05). 5. 악 안연외상 경험률은 남학생이 높게 나타났으며(p<0.01), 악안면외상 경험 경로 중 넘어짐이 가장 많았으며, 운동, 기타 순으로 나타났다. 6. 악안면 외상과 측두하악장애와의 관련성은 악악면외상과 측두하악관절잡 음 간에 통계적으로 유의한 관련성을 보였다(p<0.01). 이상의 결과 악안면외상 경험유무와 측두하악장애 간에는 관련성이 존재하며 악안면외상을 측두하악장애 발생의 기여요인으로 볼 수 있겠다. 따라서 향후 측두하악장애를 일으키는 요인이 무엇인지 그 관련요인에 대한 추가연구가 필요하다고 사료된다.

• Journal of Astronomy and Space Sciences
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• 제33권2호
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• pp.127-135
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• 2016

Inactive space objects are usually rotating and tumbling as a result of internal or external forces. KOREASAT 1 has been inactive since 2005, and its drift trajectory has been monitored with the optical wide-field patrol network (OWL-Net). However, a quantitative analysis of KOREASAT 1 in regard to the attitude evolution has never been performed. Here, two optical tracking systems were used to acquire raw measurements to analyze the rotation period of two inactive satellites. During the optical campaign in 2013, KOREASAT 1 was observed by a 0.6 m class optical telescope operated by the Korea Astronomy and Space Science Institute (KASI). The rotation period of KOREASAT 1 was analyzed with the light curves from the photometry results. The rotation periods of the low Earth orbit (LEO) satellite ASTRO-H after break-up were detected by OWL-Net on April 7, 2016. We analyzed the magnitude variation of each satellite by differential photometry and made comparisons with the star catalog. The illumination effect caused by the phase angle between the Sun and the target satellite was corrected with the system tool kit (STK) and two line element (TLE) technique. Finally, we determined the rotation period of two inactive satellites on LEO and geostationary Earth orbit (GEO) with light curves from the photometry. The main rotation periods were determined to be 5.2 sec for ASTRO-H and 74 sec for KOREASAT 1.

• 의료법학
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• 제19권2호
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• pp.173-207
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• 2018

일본은 고령화가 빠르게 진전되어 이미 총 인구 중 65세 이상 인구가 차지하는 비율이 20% 이상인 초고령사회에 해당한다. 일본의 판례는 요양시설에 입소한 고령자가 사상을 당한 다수의 사안에서 요양시설의 손해배상책임을 인정하였다. 구체적인 사안들은 ①전도 또는 전락, ②배회 또는 무단외출, ③질식, ④욕창 및 ⑤이용자 간 사고의 5가지 유형으로 나눌 수 있다. 판례는 대부분의 사안에서 채무불이행책임을 중심으로 검토하였으며, 과실 또는 안전배려의무 위반을 인정하였다. 과실 또는 의무위반은 시설의 관리자 또는 직원이 입소자를 주시하고 주의를 기울일 의무를 위반한 경우 뿐 아니라, 경우에 따라서는 인적·물적 체제를 정비하지 못한 것 자체만으로도 인정된다. 특히 일본에서는 신속한 권리 구제를 위하여 손해배상에 관한 특약 조항이 있는 경우 원고는 사고 및 손해의 발생을 주장·입증하면 충분하고, 피고로서는 불가항력에 의한 사고임을 주장·입증하지 않는 한 손해배상책임을 부담한다고 하여 입증책임의 전환을 인정한다. 그런데 요양시설의 손해배상책임은 시설에서 대상자의 입소를 허락하고 서비스이용계약을 체결하는 것을 주저할 만큼 과중한 것이어서는 안 될 것이다. 이러한 점에서 일본 재판소가 상대적으로 과실상계와 소인감액을 널리 인정한 논리는 충분히 음미할 필요성이 있다. 개호사고 소송에서 법원의 판단은 구체적인 사실관계에 근거한 사례판단이지만, 개호사업자와 이용자에 대한 관계를 살펴보는 것은 향후 우리나라에서 개호사고 소송의 심리·판단 뿐 아니라 요양자의 일탈 및 사고 등을 인식할 수 있는 체제를 구축하기 위한인적·물적 체제를 구축하는 기준을 제시하는 법안을 입안함에 있어서도 시사점을 제공할 수 있을 것이다.