• Title/Summary/Keyword: Reference Stress

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A Study on Ground Reinforcement Effect with Structural Forms of Improved Soil (개량체 구조형상에 따른 지반보강효과 연구)

  • Park, Kyunghan;Jang, Gisoo;Lee, Song
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.1
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    • pp.25-34
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    • 2014
  • The aim of this study is to analyze the mechanical characteristics and settlement feature of the composite ground with structural form changes. The laboratory model test is a soil tanker to be contained with clay and grid form improved soil, which is conducted in total 9 case with the uniaxial compressive strength of improved soil and replacement ratio of improved soil. The numerical analysis for variation of stress distribution ratio with depth was performed in the same conditions which are the laboratory model test. As a result, stress distribution ratios in mid and high replacement ratio are increasing and settlement is decreasing, except low replacement ratio. This study is presented for form effect ratio and settlement reduction factor with change of structure form, which is able to be helpful in further research and reference for change of structural forms at composite ground.

Antioxidant Activity and Protective Effect of Leaf Extract from Diospyros lotus on Oxidative Stress of Red Blood Cells (고욤 잎 추출물의 항산화 활성 및 적혈구 산화적 손상에 대한 보호 효과)

  • Kim, Hyeon Soo;Kang, Hyun Ju;Jeon, In Hwa;Mok, Ji Ye;Park, Young Kyun;Shin, Jun Ho;Kim, Jang Ho;Jang, Seon Il
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.5
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    • pp.631-636
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    • 2013
  • This study was to evaluate the antioxidant properties of the leaf extracts of Diospyros lotus (DLE) on the chemical-induced free radical and rat red blood cell (RBC) oxidative damage in vitro. DLE were prepared by extracting with water. DLE showed the high antioxidant activities on the scavenging of 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)-induced radicals. An antioxidant activities of DLE was similar to the reference antioxidant butylated hydroxytoluene (BHT) and (${\pm}$)6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox). Reducing power of $1,000{\mu}g/mL$ DLE also was similar to the vitamin C. In RBC, oxidative hemolysis induced by the aqueous peroxyl radical generator (2,2'-Azobis (2-methylpropionamidine) dihydrochloride (AAPH)) were significantly suppressed by DLE in a dose-dependent manner. Furthermore, DLE prevented the depletion of cytosolic antioxidant glutathione in RBC damaged with AAPH. These results suggest that DLE may has value as natural product with its high quality antioxidant properties against oxidative stress.

Three Dimensional Stress Analysis of a Dental Implant with Central Cavity (중공을 가지는 치과용 임플란트의 3차원 응력해석)

  • Kim, Jin-Gon;Lee, Jae-Kon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.5
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    • pp.2197-2202
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    • 2011
  • In this study, we propose a new short dental implant and investigate its bio-mechanical characteristics by using three dimensional finite element analyses. The proposed dental implant has the central cavity which can be integrated with the core of cancellous bone remained by trepanning drill. We take the Bicon short implant as a reference model for studying the effects according to the shape of cavity. The parametric finite element model using ANSYS APDL has been built to determine which length, diameter and thread of central cavity would be effective to dissipate stress. The reduction of undesirable stress in adjacent bone which can suppress bone defects and the eventual failure of implants. The numerical results shows that the cavity of well-determined shape has the beneficial effects on reducing the bone absorption in cancellous bone.

In-Plane Collision Analysis of Perforated Steel Plates (면내 충돌에 의한 유공 강판의 거동 해석)

  • Kang, Dong-Baek;Lee, Ju-Won;Na, Won-Bae;Kim, Jeong-Tae
    • Journal of Ocean Engineering and Technology
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    • v.22 no.4
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    • pp.65-71
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    • 2008
  • In many cases, open-type plate breakwaters use plates with multiple holes; the holes serve as energy dissipaters and weight reducers. Because of the multi-holes configuration, stress concentration should be considered during the design process. Among several design loading conditions, the loads from a possible collision with a man-made vessel or other unexpected events many damage a multi-perforated steel plate. In that case, the structural behavior of a multi-perforated steel plate is quite significant, and is not well understood. This study presents a collision analysis for a multi-perforated steel plate. First, four different perforation topologies (three with circles and one with squares) were selected to investigate the effect of different hole shapes on the structural response. Second, the wave force at a specific site was calculated and loaded onto a steel plate as a static load. The static stresses were used for reference values. Third, two rigid body impacters (cubical & cylindrical) were applied to the steel plates to investigate the transient stress responses. In addition, two different impacting angles ($45^{\circ}\;&\;90^{\circ}$) were selected to investigate the angle effect. From the collision analysis, the significance of the transient stresses was emphasized.

Transcriptome profiling of the coffee (C. arabica L.) seedlings under salt stress condition

  • Haile, Mesfin;Kang, Won Hee
    • Journal of Plant Biotechnology
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    • v.45 no.1
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    • pp.45-54
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    • 2018
  • This research was conducted to study the gene expression of coffee (Coffea arabica L.) seedlings under salt stress condition. A solution of five percent ($2.3dS\;m^{-1}$) deep sea water was used for the salt treatment, and it was thereby compared to normal irrigation water ($0.2dS\;m^{-1}$) used for the control treatment. The mRNA was extracted from the leaves of the coffee seedlings for a comprehensive analysis. In this study, a total of 19,581 genes were identified and aligned to the reference sequences available in the coffee genome database. The gene ontology analysis was performed to estimate the number of genes associated with the identified biological processes, cellular components and molecular functions. Among the 19,581 genes, 7369 (37.64%) were associated with biological processes, 5909 (30.18%) with cellular components, and 5325 (27.19%) with molecular functions. The remaining 978 (4.99%) genes were therefore grouped as unclassified. A differential gene expression analysis was performed using the DESeq2 package to identify the genes that were differentially expressed between the treatments based on fold changes and p-values. Namely, a total of 611 differentially expressed genes were identified (treatment/control) in that case. Among these, 336 genes were up-regulated while 275 of the genes were down-regulated. Of the differentially expressed genes, 60 genes showed statistically significant (p < 0.05) expression, 44 of which were up-regulated and 16 which were down-regulated. We also identified 11 differentially expressed transcription factor genes, 6 of which were up-regulated and rest 5 genes were down-regulated. The data generated from this study will help in the continued interest and understanding of the responses of coffee seedlings genes associated with salinity stress, in particular. This study will also provide important resources for further functional genomics studies.

Brief review of cancer treatment focused on JIJU(積聚) (적취(積聚)를 위주로 한 종양(腫瘍)의 치법(治法)에 관한 소고(小考))

  • Park, Jae-Hyun;Moon, Goo
    • Journal of Korean Traditional Oncology
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    • v.13 no.1
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    • pp.1-11
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    • 2008
  • Objectives: To grasp the traditional stream of cancer treatment inherited from the previous doctors. Methods: The author's research has been performed cancer treatment based on JIJU(積聚) taking the original text as a reference. Results & Conclusion: The general three outlines and five detailed rules of cancer treatment have been obtained as follows. The first outline of cancer treatment is that reinforced vital function makes cancer reduce naturally. the second is that Harmless cancer can coexist in human beings and aging with them. and the third is that Elimination and reinforcing therapies should be executed in appropriate era and those therapies should utilize appropriate methods. The first detailed rule of cancer treatment is when using reinforcing therapy, it must applicate mildly and when using elimination therapy, it must applicate calmly. The second detailed rule is that the methods of cancer treatment are different from each cancer stage. The concentration should be made on reinforcing therapy at early stage while reinforcing and elimination therapies must be conducted together at middle stage. At terminal stage reinforcing therapy is the sole method to be taken. The third detailed rule is that the basis property of cancer drug is warm nature and extremely biased property should be avoided and when complication arises (eg. inflamatory disease, cancer fever, etc), cold or cool nature can be applied. The fourth detailed rule is that Cancer drug must have the effect eliminating the blood stasis, phlegm and excessive fluid, all together. The fifth detailed rule is that Physicians have to control patient's stress or stress related symptom and teach patients about right way of taking care of themselves and patients should take hygienic rules with their free will by themselves (eg diet, exercise, stress, etc)

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Statistical Analysis of Determining Optimal Monitoring Time Schedule for Crop Water Stress Index (CWSI) (작물 수분 스트레스 지수 산정을 위한 최적의 관측 간격과 시간에 대한 통계적 분석)

  • Choi, Yonghun;Kim, Minyoung;Oh, Woohyun;Cho, Junggun;Yun, Seokkyu;Lee, Sangbong;Kim, Youngjin;Jeon, Jonggil
    • Journal of The Korean Society of Agricultural Engineers
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    • v.61 no.6
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    • pp.73-79
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    • 2019
  • Continuous and tremendous data (canopy temperature and meteorological variables) are necessary to determine Crop Water Stress Index (CWSI). This study investigated the optimal monitoring time and interval of canopy temperature and meteorological variables (air temperature, relative humidity, solar radiation and wind speed) to determine CWSIs. The Nash-Sutcliffe model efficiency coefficient (NSE) was used to quantitatively describe the accuracy of sampling method depending upon various time intervals (t=5, 10, 15, 20, 30 and 60 minutes) and CWSIs per every minute were used as a reference. The NSE coefficient of wind speed was 0.516 at the sampling time of 60 minutes, while the ones of other meteorological variables and canopy temperature were greater than 0.8. The pattern of daily CWSIs increased from 8:00 am, reached the maximum value at 12:00 pm, then decreased after 2:00 pm. The statistical analysis showed that the data collection at 11:40 am produced the closest CWSI value to the daily average of CWSI, which indicates that just one time of measurement could be representative throughout the day. Overall, the findings of this study contributes to the economical and convenient method of quantifying CWSIs and irrigation management.

Postbiotics Enhance NK Cell Activation in Stress-Induced Mice through Gut Microbiome Regulation

  • Jung, Ye-Jin;Kim, Hyun-Seok;Jaygal, Gunn;Cho, Hye-Rin;Lee, Kyung bae;Song, In-bong;Kim, Jong-Hoon;Kwak, Mi-Sun;Han, Kyung-Ho;Bae, Min-Jung;Sung, Moon-Hee
    • Journal of Microbiology and Biotechnology
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    • v.32 no.5
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    • pp.612-620
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    • 2022
  • Recent studies have revealed that probiotics and their metabolites are present under various conditions; however, the role of probiotic metabolites (i.e., postbiotics in pathological states) is controversial. Natural killer (NK) cells play a key role in innate and adaptive immunity. In this study, we examined NK cell activation influenced by a postbiotics mixture in response to gut microbiome modulation in stress-induced mice. In vivo activation of NK cells increased in the postbiotics mixture treatment group in accordance with Th1/Th2 expression level. Meanwhile, the Red Ginseng treatment group, a reference group, showed very little expression of NK cell activation. Moreover, the postbiotics mixture treatment group in particular changed the gut microbiome composition. Although the exact role of the postbiotics mixture in regulating the immune system of stress-induced mice remains unclear, the postbiotics mixture-induced NK cell activation might have affected gut microbiome modulation.

Banana agriculture waste as eco-friendly material in fibre-reinforced concrete: An experimental study

  • Mohammed M., Attia;Abd Al-Kader A., Al Sayed;Bassam A., Tayeh;Shymaa M.M., Shawky
    • Advances in concrete construction
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    • v.14 no.5
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    • pp.355-368
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    • 2022
  • This paper investigates the impact of length and volume fractions (VFs) of banana fibres (BFs) on the mechanical and physical properties of concrete. The mechanical properties were compressive strength, splitting tensile, flexural strength, and bond stress, while the physical properties were unit weight and absorption. The slump test was used to determine workability. The concrete's behaviour with BFs was studied using scanning electron microscopy. Experimental work of concrete mixtures with BFs of various lengths (12 mm, 25 mm, and 35 mm) and VFs (0%, 0.5%, 1.0%, and 1.5%) were carried out. The samples did not indicate any agglomeration of fibres or heterogeneity during mixing. The addition of BFs to concrete with VFs of up to 1.50% for all fibre lengths have a significant impact on mechanical properties, also the longer fibres performed better than shorter ones at all volume fractions of BFs. The mix10, which contain BFs with VFs 1.5% and length 35 mm, demonstrated the highest mechanical properties. The compressive strength, splitting tensile, flexural strength, and bond stress of the mix10 were 37.71 MPa, 4.27 Mpa, 6.12 MPa, and 6.75 MPa, an increase of 7.37%, 20.96%, 24.13%, and 11.2% over the reference concrete, which was 35.12 MPa, 3.53 MPa, 4.93 MPa, and 6.07 MP, respectively. The absorption is increased for all lengths by increasing the VFs up to 1.5%. Longer fibres have lower absorption, while shorter fibres have higher absorption. The mix8 had the highest absorption of 4.52%, compared to 3.12% for the control mix. Furthermore, the microstructure of concrete was improved through improved bonding between the fibres and the matrix, which resulted in improved mechanical properties of the composite.

Physiological Data Monitoring of Physical Exertion of Construction Workers Using Exoskeleton in Varied Temperatures

  • Ibrahim, Abdullahi;Okpala, Ifeanyi;Nnaji, Chukwuma
    • International conference on construction engineering and project management
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    • 2022.06a
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    • pp.1242-1242
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    • 2022
  • Annually, several construction workers fall ill, are injured, or die due to heat-related exposure. The prevalence of work-related heat illness may rise and become an issue for workers operating in temperate climates, given the increase in frequency and intensity of heatwaves in the US. An increase in temperature negatively impacts physical exertion levels and mental state, thereby increasing the potential of accidents on the job site. To reduce the impact of heat stress on workers, it is critical to develop and implement measures for monitoring physical exertion levels and mental state in hot conditions. For this, limited studies have evaluated the utility of wearable biosensors in measuring physical exertion and mental workload in hot conditions. In addition, most studies focus solely on male participants, with little to no reference to female workers who may be exposed to greater heat stress risk. Therefore, this study aims to develop a process for objective and continuous assessment of worker physical exertion and mental workload using wearable biosensors. Physiological data were collected from eight (four male and four female) participants performing a simulated drilling task at 92oF and about 50% humidity level. After removing signal artifacts from the data using multiple filtering processes, the data was compared to a perceived muscle exertion scale and mental workload scale. Results indicate that biosensors' features can effectively detect the change in worker physical and mental state in hot conditions. Therefore, wearable biosensors provide a feasible and effective opportunity to continuously assess worker physical exertion and mental workload.

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