• Korean Chemical Engineering Research
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• 제61권1호
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• pp.155-161
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• 2023

이온 농도 분극 현상은 전기투석, 전기화학 전지에서 일어나는 기초 이동 현상일 뿐만 아니라, 생체 물질 전처리용 농축 장치의 핵심 기작으로 활용된다. 외부 인가 전압에 의해 발생한 이온 농도 분극 현상은 분석 물질의 농축에 필요한 국소적으로 증폭된 전기장을 통해 물질의 농축을 가능케 한다. 그러나 기존의 농축 기작은 농축의 평형 지점이 불분명하며, 농축 플러그의 유체역학적 불안정성의 두가지 문제점을 가지고 있다. 본 연구에서는, 이온 농도 분극 기반의 농축 기작의 한계점을 해결하기 위해 막다른 미세유로와 양이온 교환막을 사용한 농축 방법을 연구하였다. 막다른 미세유로의 공간 제약적 구조를 통해 유체역학적 안정성을 확보할 수 있으며, 분석 물질의 농축 지점이 이온 공핍 영역의 충격 전단과 일치함을 수치적으로 확인하였다. 또한 농축 공정의 핵심 인자로써 인가 전압과 미세유로의 체적 전하 농도를 변화시켜가며, 농축 물질의 전기동역학적 거동을 연구하였다. 본 연구의 결과는 현장 진단 검사(point-of-care)와 같은 초단시간의 농축을 필요로 하는 미세유체역학 장치에 유효한 기작으로 사용될 수 있을 것이다.

• 한국ITS학회 논문지
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• 제18권6호
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• pp.43-59
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• 2019

현재 국내에서 사용되고 있는 교통신호제어기는 220V의 고전압을 신호등에 일대일로 직접 전달하는 스위치 제어 방식이다. 이러한 방식은 교통신호제어기와 신호등들을 연결하는 데 상대적으로 많은 케이블이 소요되고, 또한 감전에 대한 우려가 있다. 이에 따라 도로교통공단에서는 경찰청 교통신호제어기 표준규격서에 디지털 통신 방식을 이용한 디지털 교통신호제어기의 규격을 추가하였다. 본 연구에서는 이러한 표준규격서를 바탕으로 디지털 교통신호제어기를 개발하고자 하였다. 또한 디지털 교통신호제어기와 아날로그 교통신호제어기가 혼재되어 있어도 현재 운영 중인 신호제어시스템에서 운영이 가능함을 검증하였다.

• Journal of Trauma and Injury
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• 제30권3호
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• pp.80-86
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• 2017

Purpose: To analyze the data of patients who suffered trauma in a cultivator accident and visited the trauma center in rural Gyeongbuk Province. Methods: We retrospectively reviewed the medical records and Korean Trauma Data Bank data of 120 patients who suffered cultivator-related traumas and visited the rural regional trauma center in Gyeongbuk Province from January to December 2015. Results: The age of the patients ranged from 35 to 96 years (mean, 70 years). Ninety-one (75.8%) patients were men, and twenty-nine (24.2%) were women. Most of the patients were in their 70s (46 men [50.5%] and 13 women [44.8%]). In total, 113 patients (94.1%) arrived at the regional trauma center by ground transport and 7 (5.9%) arrived by air transport. Ninety-eight patients (81.7%) were transported to the regional trauma center directly from the scene of the accident, and twenty-two (18.3%) were transferred from another medical institute. The mean time from the accident to arrival at the emergency department was 139 minutes, and only 46 patients (38.3%) arrived within 1 hour. Twelve (10.0%) patients died, including two deaths on arrival and two post- cardiopulmonary resuscitation deaths in the emergency department. All deaths were of male cultivator operators. The causes of death were shock (hypovolemic, traumatic, or septic), subdural hematoma (open), hemothorax, rhabdomyolysis, and pneumonia. Conclusions: As the government - led regional trauma center project is on process, it would be clinically important to summarize the initial outcome of cultivator injuries, which are characteristically found more in regional trauma centers in the rural area, and have high mortality. Based on this study, in the future, it will be necessary to follow up and analyze more number of patients and to construct accurate database about trauma cases related to cultivator in Gyeongbuk region.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.44-54
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• 2019

Geldanamycin and its derivatives, inhibitors of heat shock protein 90, are considered potent anticancer drugs, although their biosynthetic pathways have not yet been fully elucidated. The key step of conversion of 4,5-dihydrogeldanamycin to geldanamycin was expected to catalyze by a P450 monooxygenase, Gel16. The adequate bioconversions by cytochrome P450 mostly rely upon its interaction with redox partners. Several ferredoxin and ferredoxin reductases are available in the genome of certain organisms, but only a few suitable partners can operate in full efficiency. In this study, we have expressed cytochrome P450 gel16 in Escherichia coli and performed an in vitro assay using 4,5-dihydrogeldanamycin as a substrate. We demonstrated that the in silico method can be applicable for the efficient mining of convenient endogenous redox partners (9 ferredoxins and 6 ferredoxin reductases) against CYP Gel16 from Streptomyces hygroscopicus. The distances for ligand FDX4-FDR6 were found to be $9.384{\AA}$. Similarly, the binding energy between Gel16-FDX4 and FDX4-FDR6 were -611.88 kcal/mol and -834.48 kcal/mol, respectively, suggesting the lowest distance and binding energy rather than other redox partners. These findings suggest that the best redox partners of Gel16 could be NADPH ${\rightarrow}$ FDR6 ${\rightarrow}$ FDX4 ${\rightarrow}$ Gel16.

• 한국기계가공학회지
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• 제20권3호
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• pp.60-67
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• 2021

Recently, research attention has been focused on vibration-free vehicles to transport small numbers of expensive electronic products. Vibration-free vehicles can be used to transport expensive test equipment or semiconductors, mainly produced in the domestic IT industry, and can serve as a readily available transportation system for short driving distances due to the increased efficiency on narrow national highways. This study was aimed at developing a Z-Spring to minimize the vibration by installing an air spring instead of the plate spring applied to conventional freight cars and to prevent the damage of the loaded cargo from the shock occurring during movement. The mechanical properties (elastic modulus, tensile strength, and shear strength) of carbon fiber (CF) and glass fiber (GF) prepreg were derived, and ANSYS ACP PrepPost analyses were performed. It was observed that in the case of hybrid composites, the total deformation and equivalent stress are higher than that of CFRP; however, in terms of the unit cost, the hybrid Z-Spring is more inexpensive and durable compared to the GF.

• Journal of Animal Science and Technology
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• 제64권1호
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• pp.110-122
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• 2022

The reduction of milk yield caused by heat stress in summer is the main condition restricting the economic benefits of dairy farms. To examine the impact of hyperthermia on bovine mammary epithelial (MAC-T) cells, we incubated the MAC-T cells at thermal-neutral (37℃, CON group) and hyperthermic (42℃, HS group) temperatures for 6 h. Subsequently, the cell viability and apoptotic rate of MAC-T cells, apoptosis-related genes expression, casein and amino acid transporter genes, and the expression of the apoptosis-related proteins were examined. Compared with the CON group, hyperthermia significantly decreased the cell viability (p < 0.05) and elevated the apoptotic rate (p < 0.05) of MAC-T cells. Moreover, the expression of heat shock protein (HSP)70, HSP90B1, Bcl-2-associated X protein (BAX), Caspase-9, and Caspase-3 genes was upregulated (p < 0.05). The expression of HSP70 and BAX (pro-apoptotic) proteins was upregulated (p < 0.05) while that of B-cell lymphoma (BCL)2 (antiapoptotic) protein was downregulated (p < 0.05) by hyperthermia. Decreased mRNA expression of mechanistic target of rapamycin (mTOR) signaling pathway-related genes, amino acid transporter genes (SLC7A5, SLC38A3, SLC38A2, and SLC38A9), and casein genes (CSNS1, CSN2, and CSN3) was found in the heat stress (HS) group (p < 0.05) in contrast with the CON group. These findings illustrated that hyperthermia promoted cell apoptosis and reduced the transport of amino acids into cells, which inhibited the milk proteins synthesis in MAC-T cells.

• 한국전산유체공학회지
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• 제19권4호
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• pp.68-74
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• 2014

This computational study features the transient compressible and inviscid flow analysis on a metallic plasma discharge from the opposing composite electrodes which is subjected to pulsed electric power. The computations have been performed using the flux corrected transport algorithm on the axisymmetric two-dimensional domain of electrode gap and outer space along with the calculation of plasma compositions and thermophysical properties such as plasma electrical conductivity. The mass ablation from aluminum electrode surfaces are modeled with radiative flux from plasma column experiencing intense Joule heating. The computational results shows the highly ionized and highly under-expanded supersonic plasma discharge with strong shock structure of Mach disk and blast wave propagation, which is very similar to muzzle blast or axial plasma jet flows. Also, the geometrical effects of composite electrodes are investigated to compare the amount of mass ablation and penetration depth of plasma discharge.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1494-1498
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• 2007

Impulsive shooting noise is basically complex phenomenon which contains the linear and non-linear characteristics. For those reasons, numerical analysis of impulsive shooting noise has the difficulties in control of the numerical stability and accuracy on the simulation. In this research, Wave-number Extended Finite Volume Scheme (WEFVS) is applied to the numerical analysis of impulsive shooting noise. In the muzzle blast flow simulation, the generation of the precursor wave and the induced vortex ring are observed. Consequently, blast wave. vortex ring interaction and vortex ring. bow shock wave interaction are evaluated on the shooting process using the accurate and stable scheme. The sound generation in the interactions can be explained by the vorticity transport theorem. The shear layer is evolved behind the projectiles due to the jet flow. In these computations, the impulsive shooting noise is generated by the complex interaction with shooting process and is propagated to the far-field boundary. The impulsive shooting noise generation can be observed by the applications of WEFVS and analyzed by the physical phenomena.

• Journal of Microbiology and Biotechnology
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• 제30권2호
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• pp.237-243
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• 2020

A novel psychrotolerant Psychrobacillus strain PB01, isolated from an Antarctic iceberg, was comparatively analyzed with five related strains. The complete genome of strain PB01 consists of a single circular chromosome (4.3 Mb) and a plasmid (19 Kb). As potential low-temperature adaptation strategies, strain PB01 has four genes encoding cold-shock proteins, two genes encoding DEAD-box RNA helicases, and eight genes encoding transporters for glycine betaine, which can serve as a cryoprotectant, on the genome. The pan-genome structure of the six Psychrobacillus strains suggests that strain PB01 might have evolved to adapt to extreme environments by changing its genome content to gain higher capacity for DNA repair, translation, and membrane transport. Notably, strain PB01 possesses a complete TCA cycle consisting of eight enzymes as well as three additional Helicobacter pylori-type enzymes: ferredoxin-dependent 2-oxoglutarate synthase, succinyl-CoA/acetoacetyl-CoA transferase, and malate/quinone oxidoreductase. The co-existence of the genes for TCA cycle enzymes has also been identified in the other five Psychrobacillus strains.

• 한국초지조사료학회지
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• 제20권2호
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• pp.97-102
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• 2000

To increase thennotolerance of forage crops, transgenic rice plants as a model for transformation of monocots were generated. A cDNA encoding the chloroplast-localized small heat shock protein (small HSP) of rice, Oshsp21, was introduced into rice plants via Agrobacterium-mediated gene transfer system. Calli induced from scutella were co-cultivated with a A. tumefaciens strain EHAlOl canying a plasmid, pIGhsp21. A large number of transgenic plants were regenerated on a medium containing hygromycin. Integration of Oshsp2l gene was confirmed by PCR and Southern blot analyses with genomic DNA. Northern blot and immunoblot analyses revealed that the Oshsp21 gene was constitutively expressed and accumulated as mature protein in transgenic plants. Effects of constitutive expression of the OshspZl on thermotolerance were first probed with the chlorophyll fluorescence. Results indicate that inactivation of electron transport reactions in photosystem I1 (PSII), were mitigated by constitutive expression of the Oshsp21. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery during heat stress. (Key words : Thermotolerance, Rice, Transgenic, cDNA)