• Laboraroty Animal Research
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• 제34권4호
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• pp.302-310
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• 2018

CD47 (integrin-associated protein), a multi-spanning transmembrane protein expressed in all cells including red blood cells (RBCs) and leukocytes, interacts with signal regulatory protein ${\alpha}$ ($SIRP{\alpha}$) on macrophages and thereby inhibits phagocytosis of RBCs. Recently, we generated a novel C57BL/6J CD47 knockout ($CD47^{-/-}$ hereafter) mouse line by employing a CRISPR/Cas9 system at Center for Mouse Models of Human Disease, and here report their hematological phenotypes. On monitoring their birth and development, $CD47^{-/-}$ mice were born viable with a natural male-to-female sex ratio and normally developed from birth through puberty to adulthood without noticeable changes in growth, food/water intake compared to their age and sex-matched wild-type littermates up to 26 weeks. Hematological analysis revealed a mild but significant reduction of RBC counts and hemoglobin in 16 week-old male $CD47^{-/-}$ mice which were aggravated at the age of 26 weeks with increased reticulocyte counts and mean corpuscular volume (MCV), suggesting hemolytic anemia. Interestingly, anemia in female $CD47^{-/-}$ mice became evident at 26 weeks, but splenomegaly was identified in both genders of $CD47^{-/-}$ mice from the age of 16 weeks, consistent with development of hemolytic anemia. Additionally, helper and cytotoxic T cell populations were considerably reduced in the spleen, but not in thymus, of $CD47^{-/-}$ mice, suggesting a crucial role of CD47 in proliferation of T cells. Collectively, these findings indicate that our $CD47^{-/-}$ mice have progressive hemolytic anemia and splenic depletion of mature T cell populations and therefore may be useful as an in vivo model to study the function of CD47.

• 한국건설관리학회논문집
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• 제20권1호
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• pp.52-61
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• 2019

2017년 6월 30일 국토교통부는 주차단위구획의 최소 크기를 확대하는 것을 입법 예고하였다. 주차단위구획의 확대는 주차장 연면적의 증가를 초래하여 아파트 분양가를 상승시킬 우려가 있다. 그러므로 주차장의 기둥 간격과 개수를 조정하고, 주차효율이 좋은 8-Bay 장스팬 주차모듈을 적용할 필요가 있다. 연구결과, 주차단위구획을 확대한 6-Bay 주차모듈과 8-Bay 주차모듈의 공사비는 거의 비슷한 수준이었으나, 8-Bay 주차모듈의 연면적 감소 효과가 확인되어 8-Bay 주차모듈이 더 경제적인 것으로 나타났다. 8-Bay 주차모듈의 공사비를 분석한 결과, 탈형데크플레이트 RC공법을 적용한 모듈이 가장 경제성이 있는 것으로 나타났다. PC 복합화공법은 부재의 체적 증가로 인해 비교적 공사비가 높게 나타났으나, 프리스트레스를 적용하여 보 춤을 감소시키면 경제성을 확보할 수 있을 것으로 확인되었다. 또한 중공슬래브 공법 모듈은 가장 공사비가 높게 나타났으나, $1m^2$당 공사비가 가장 낮아 비용적 측면에서 아파트 주차장의 구조공법으로 적용 가능성을 확인하였다. 이 연구는 8-Bay 주차모듈의 공사비를 분석하고 비용적 측면에서 경제성을 확인하였다는 점에서 의의를 가지며, 향후에 8-Bay 주차모듈을 적용한 최적의 공법을 도출하는데 기초자료로 활용될 것으로 기대된다.

• 농촌계획
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• 제24권4호
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• pp.135-146
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• 2018

A Visual landscape planning and management system has been introduced and implemented by each ministry so as to solve the problems of visual landscape destruction due to recognition on the value of natural landscape of beautiful territory and various development projects. At present, this system emphasizes the importance of the visual and perceptual aspect of the landscape however, there is a lack of techniques required for comprehensively predicting, evaluating, and managing it. Furthermore, sustainable landscape management after the completion of development projects has been inadequately carried out, as the focus has been only on consultation in the planning process of the development project in institutional performance. To this end, we presented objective and standardized criteria to predict and judge the effects of development projects on landscapes before project implementation. During the implementation of the development project, the influence of the visual landscape becomes accumulated in the construction progress stage. There is a need to identify the main viewpoints and to examine the continuous changes in the landscape-influencing factors, owing to the remarkable influences on the landscape, such as the change in the topography and the change caused by the artificial structure. During the stage of managing the influence on the visual landscape after the completion of the project, the influence on landscape should be monitored by measuring the change in the continuous landscape-influencing factors and determining the extent to which the actual reduction plan has been implemented. These processes should be performed continuously to maintain the quality of the visual landscape. The change in the landscape caused by the development project is shown to cause relatively greater visual damage than other factors composing the landscape owing to the influence of the artificial factors including the structure or the building. This shows that not only detailed examination of the visual impact before the development project but also continuous management is required during and after the development project. For this purpose, we derived eight landscape-influencing factors including form/shape, line, color, texture, scale/volume, height, skyline, and landscape control point. The proposed considering to be of high utilization in that it has a clear target of the landscape influencing factors.

• 자원리싸이클링
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• 제29권6호
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• pp.15-26
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• 2020

최근 미세플라스틱의 발생 측면에서 폐플라스틱의 친환경적 처리에 대한 관심이 증대하고 있다. 이에, 폐플라스틱의 재활용이 폐기물 간소화, 이산화탄소 배출 감소 및 부가가치 제품 재생산의 이점을 제공하기 때문에 매우 중요하다고 할 수 있다. 특히, 친환경적인 폐플라스틱의 재활용을 위해서는 물리적 선별방법을 통해야 하며, 그 중에서도 폐플라스틱내의 재질별 분리가 가능한 부유선별이 물질재활용 측면에서 매우 효과적인 분리방법으로 잘 알려져 있다. 따라서, 본 총설에서는 혼합 폐플라스틱의 효과적인 재질 분리를 하기 위한 부유 선별의 연구 동향을 조사하였다. 추가적으로 보고된 연구결과들을 통하여 플라스틱의 원재료인 폴리머로부터 기능성 신소재로서의 활용에 대한 접근방법을 요약 정리하였다.

• 한국환경보건학회지
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• 제46권6호
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• pp.719-725
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• 2020

Objectives: With the growth of national interest in fine particulate matter, many complaints about pollutants emitted from air pollution emitting facilities have arisen in recent years. In particular, it is thought that a large volume of particulate pollutants are discharged from workplaces that use Solid Refuse Fuel (SRF). Therefore, particulate contaminants generated from SRF were measured and analyzed in this study in terms of respective particle sizes. Methods: In this study, particulate matter in exhaust gas was measured by applying US EPA method 201a using a cyclone. This method measures Filterable Particulate Matter (FPM), and does not consider the Condensable Particulate Matter (CPM) that forms particles in the atmosphere after being discharged as a gas in the exhaust gas. Results: The mass concentration of Total Suspended Particles (TSP) in the four SRF-using facilities was 1.16 to 11.21 mg/Sm3, indicating a very large concentration deviation of about 10 times. When the fuel input method was the continuous injection type, particulate matter larger than 10 ㎛ diameter showed the highest particle size fraction, followed by particulate matter smaller than 10 ㎛ and larger than 2.5 ㎛, and particulate matter of 2.5 ㎛ or less. Contrary to the continuous injection type, the batch injection type had the smallest particle size fraction of particulate matter larger than 10 ㎛. The overall particulate matter decreased as the operating load factor decreased from 100% to 60% at the batch input type D plant. In addition, as incomplete combustion significantly decreased, the particle size fraction also changed significantly. Both TSP and heavy metals (six items) satisfied the emissions standards. The measured value of the emission factor was 38-99% smaller than the existing emissions factor. Conclusions: In the batch injection facility, the particulate matter decreased as the operating load factor decreased, as did the particle size fraction of the particulate matter. These results will help the selection of effective methods such as reducing the operating load factor instead of adjusting the operating time during emergency reduction measures.

• Advances in nano research
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• 제10권2호
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• pp.115-128
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• 2021

In this article, free vibration behavior of electro-magneto-thermo sandwich Timoshenko beam made of porous core and Graphene Platelet Reinforced Composite (GPLRC) in a thermal environment is investigated. The governing equations of motion are derived by using the modified strain gradient theory for micro structures and Hamilton's principle. The magneto electro are under linear function along the thickness that contains magnetic and electric constant potentials and a cosine function. The effects of material length scale parameters, temperature change, various distributions of porous, different distributions of graphene platelets and thickness ratio on the natural frequency of Timoshenko beam are analyzed. The results show that an increase in aspect ratio, the temperature change, and the thickness of GPL leads to reduce the natural frequency; while vice versa for porous coefficient, volume fractions and length of GPL. Moreover, the effect of different size-dependent theories such as CT, MCST and MSGT on the natural frequency is investigated. It reveals that MSGT and CT have most and lowest values of natural frequency, respectively, because MSGT leads to increase the stiffness of micro Timoshenko sandwich beam by considering three material length scale parameters. It is seen that by increasing porosity coefficient, the natural frequency increases because both stiffness and mass matrices decreases, but the effect of reduction of mass matrix is more than stiffness matrix. Considering the piezo magneto-electric layers lead to enhance the stiffness of a micro beam, thus the natural frequency increases. It can be seen that with increasing of the value of WGPL, the stiffness of microbeam increases. As a result, the value of natural frequency enhances. It is shown that in hc/h = 0.7, the natural frequency for WGPL = 0.05 is 8% and 14% less than its for WGPL = 0.06 and WGPL = 0.07, respectively. The results show that with an increment in the length and width of GPLs, the natural frequency increases because the stiffness of micro structures enhances and vice versa for thickness of GPLs. It can be seen that the natural frequency for aGPL = 25 ㎛ and hc/h = 0.6 is 0.3% and 1% more than the one for aGPL = 5 ㎛ and aGPL = 1 ㎛, respectively.

• 대한방사선치료학회지
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• 제33권
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• pp.55-62
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• 2021

목 적: 방사선 피부염은 유방암 방사선 치료로 인해 발생하는 가장 흔한 부작용 중 하나로 본 연구는 자세오차에 따른 피부선량 차이를 분석하여 방사선 치료 부작용을 줄이고자 한다. 대상 및 방법 : 3D 프린터를 이용하여 유방 모형을 제작하고, 그것을 팬텀에 적용하였으며, 컴퓨터단층촬영을 통해 영상을 획득하였다. 처방선량의 95%가 들어가는 치료계획용적이 체적의 95%이상이 될 수 있도록, Dmax가 처방선량의 107%넘지 않게 치료계획하였다. 자세오차는 X축, Y축, Z축으로 ±1mm/±3mm/±5mm를 동일하게 적용하여 비교평가하였다. 결 과 : 자세오차 시 피부선량의 변동성은 처방선량 대비 약 106%에서 약 123%였으며 가장 큰 피부선량의 증가는 X축의 바깥쪽(lateral) 방향 5mm 자세오차에서 49.24 Gy였다. 처방선량 대비 107%이상의 영역은 skin lateral에서 6.87 cc로 가장 넓게 나타났다. 결 론 : 좌측 유방암 용적 변조 회전 방사선 치료 시 자세오차가 일어났을 경우 X축의 바깥쪽 방향에서 처방선량 대비 가장 큰 피부선량의 차이가 나타났다. 이를 통해 치료실 CBCT 정합 시 치료받는 쪽 유방의 Y축, Z축을 정합하는 것도 물론 중요하지만 X축을 정합하는데 더 노력한다면 치료 간 피부선량의 변동성을 더 줄이기 위한 효과적인 방법으로 사료된다.

• 대한토목학회논문집
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• 제42권6호
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• pp.787-792
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• 2022

겨울철 제설염의 사용은 콘크리트의 미세조직을 손상시기게 되고 이는 내구성을 감소시켜 콘크리트의 수명 단축으로 이어진다. 이러한 단점을 개선하기 위해 상변화물질(Phase Change Material, PCM)의 잠열을 콘크리트에 적용함으로써 손상을 완화하고 제설염의 수요를 감소시킬 수 있는 융설 PCM 함침 경량골재(Phase Change Material Impregnated Light Weight Aggregate, PCM-LWA) 콘크리트를 개발하고자 한다. 콘크리트를 제작할 때, PCM을 함침하고 캡슐화한 팽창점토(Expanded Clay)는 일반골재의 50 %를 대체하여 사용되었으며, 열적 성능을 향상시키기 위해 사용된 다중벽 탄소나노튜브(Multi-walled Carbon Nano Tube, MWCNT)는 바인더 중량 대비 0.10 %, 0.15 % 및 0.20 %의 비율로 첨가되었다. PCM-LWA를 적용한 시편들의 압축강도 시험 결과 약 54 %의 강도 감소를 보였지만 MWCNT의 첨가를 통하여 PCM-LWA 콘크리트의 열적 성능을 크게 향상시켰다. 열 사이클링 시험에서 모든 시편은 15℃ ~ -5℃의 온도에서 시험하였다. 주변 온도가 0℃ 미만으로 내려갈 때, 다른 시편들의 내부 온도는 0℃ 미만으로 내려가거나 조금 웃도는 경향을 보였지만, CNT를 0.10 % 첨가한 시편의 내부 온도는 2℃로 유의미한 차이를 보였다. 0.15CNT와 0.20CNT의 경우 CNT의 함유로 인하여 과냉각이 발생하였고 열효율이 떨어지게 되어 시편 내부의 온도가 0℃ 이하로 떨어지는 것을 확인할 수 있었다. 융설 시험에서 열 사이클링 시험의 결과와 유사하게 50PCM-LWA와 0.10CNT는 얼음을 녹이는 데에 가장 뛰어난 성능을 보였지만 시간이 흐름에 따라 열전도율이 높은 0.10CNT 시편이 가장 우수한 성능을 보였다.

• 운동영양학회지
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• 제24권2호
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• pp.30-37
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• 2020

[Purpose] The present study investigated the effect of endurance exercise with blood flow restriction (BFR) performed at either 25% maximal oxygen uptake (${\dot{V}}O_2$ max) or 40% ${\dot{V}}O_2$ max) on muscle oxygenation, energy metabolism, and endocrine responses. [Methods] Ten males were recruited in the present study. The subjects performed three trials: (1) endurance exercise at 40% ${\dot{V}}O_2$ max without BFR (NBFR40), (2) endurance exercise at 25% ${\dot{V}}O_2$ max with BFR (BFR25), and (3) endurance exercise at 40% ${\dot{V}}O_2$ max with BFR (BFR40). The exercises were performed for 15 min during which the pedaling frequency was set at 70 rpm. In BFR25 and BFR40, 2 min of pressure phase (equivalent to 160 mmHg) followed by 1 min of release phase were repeated five times (5 × 3 min) throughout 15 minutes of exercise. During exercise, muscle oxygenation and concentration of respiratory gases were measured. The blood samples were collected before exercise, immediately after 15 min of exercise, and at 15, 30, and 60 minutes after completion of exercise. [Results] Deoxygenated hemoglobin (deoxy-Hb) level during exercise was significantly higher with BFR25 and BFR40 than that with NBFR40. BFR40 showed significantly higher total-hemoglobin (total-Hb) than NBFR40 during 2 min of pressure phase. Moreover, exercise-induced lactate elevation and pH reduction were significantly augmented in BFR40, with concomitant increase in serum cortisol concentration after exercise. Carbohydrate (CHO) oxidation was significantly higher with BFR40 than that with NBFR40 and BFR25, whereas fat oxidation was lower with BFR40. [Conclusion] Deoxy-Hb and total Hb levels were significantly increased during 15 min of pedaling exercise in BFR25 and BFR40, indicating augmented local hypoxia and blood volume (blood perfusion) in the muscle. Moreover, low-and moderate-intensity exercise with BFR facilitated CHO oxidation.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권4호
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• pp.49-62
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• 2022

The magnesium and iron-based layered double hydroxide (Mg-Fe LDH) was synthesized by the co-precipitation process and the bead type LDH (BLDH, 5~6 mm in diameter) was manufactured by using the Mg-Fe LDH and the starch as a binder. To evaluate the feasibility of the BLDH as the As stabilizer in the soil, various experiments were performed and the As stabilization efficiency of the BLDH was compared to that of powdered type LDH (PLDH, <149 ㎛ in diameter). For the As sorption batch experiment, the As sorption efficiency of both of the PLDH and the BLDH showed higher than 99%. For the stabilization experiment with soil, the As extraction reducing efficiency of the PLDH was higher than 87%, and for the BLDH, it was higher than 80%, suggesting that the BLDH has similar the feasibility of As stabilization for the contaminated soil, compared to the PLDH. From the continuous column experiments, when more than 7% BLDH was added into the soil, the As stabilization efficiency of the column maintained at over 91% for 7 pore volume flushing (simulating about 21 months of rainfall) and slowly decreased down to 64% after that time (to 36 months) under the non-equilibrium conditions. Results suggested that more than 7% of BLDH added in As-contaminated soil could be enough to stabilize As in soil for a long time. The main As fixation mechanisms on the LDH were also identified through the X-ray fluorescence (XRF), the X-ray diffraction (XRD), and the Fourier transform infrared (FT-IR) analyses. Results showed that the LDH has enough of an external surface adsorption capacity and an anion exchange capability at the interlayer spaces. Results of SEM/EDS and BET analyses also supported that the Mg-Fe LDH used in this study has sufficient porous structures and outer surfaces to fix the As. The reduction of carbonate (CO₃^2-) and sulfate (SO₄^2-) anions in the LDH after the reaction between As and the LDH was observed through the FT-IR, the XRF, and the XRD analyses, suggesting that the exchange of some of these anions with the arsenate (H₂AsO₄^- or HAsO₄^2-) occurs at the LDH interlayers during the stabilization process in soil.