• KSBB Journal
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• v.14 no.3
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• pp.342-350
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• 1999

Photobacterium phosphoreum was used in order to study response to heavy metal including $HgCl_2$, $CdCl_2$, $MnSO_4$ and $ZnSO_4$ in view of developing monitoring system for toxic substances. The concentrations of heavy metal causing 50% reduction($EC_{50}$) in bioluminescence intensity were determined with both free and immobilized P. phosphoreum. The bioluminescence responses were examined at various concentrations of heavy metal after 10, 20 and 30 min of exposure. The linear correlation between Gamma values and concentrations of heavy metal was obtained and $EC_{50}$ was calculated from the linear correlation. The significant inhibitory concentrations for bioluminescence emission were found to be 0.05mg/L for $HgCl_2$, 25mg/L for $CdCl_2$, 50mg/L for $MnSO_4$ and 12.5mg/L for $ZnSO_4$, respectively. The free cell and disc type were shown to be more sensitive to heavy metal than cells mixed with Na-alginate or immobilized on Sr-alginate. However, the linear regression curves were derived from the Sr-alginate immobilized cells indicating the immobilization method is a useful tool for monitoring of heavy metal under more stable condition of bioluminescence.

• Journal of the Korean Magnetics Society
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• v.5 no.3
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• pp.216-221
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• 1995

Both manufacturing parameters and particles' chemical composition controll coercivity and its distribution of magnetic particles. The coercivity and its distribution are important properties for high density magnetic recording, so these are used as tool for evaluation of reproducibility of magnetic particles. We report in this paper the applications of dM/dH versus H curve, which is derived from magnetic hysteresis loop, to the evaluation of coercivity distribution of magnetic particles and oxidation studies of recording metal particles. The coercivity distri-bution can be estimated from the full width half rnaximun (FWHM) and the peak shape of the dM/dH versus H curve. The peak shape of the curve depends upon distribution of particles' coercivity. The peak of dM/dH versus H curve becomes broad and lor is splitted into two or rmre peaks. It depends on uniformity of particles' coercivity. When the coercivity difference between Ba-Ferrite and ${\gamma}-Fe_{2}O_{3}$ is larger than 600 Oe, the peak becomes broad and is consequently splitted into two peaks. Ununiformly substituted Ba-Ferrite particles show broad peak. It is apparent that the analysis of the curve is one of sensitive measuring techniques for determination of coercivity distri-bution and studies on magnetic properties of substituted Ba-Ferrite and oxidation of magnetic recording metal particles.

• Food Science and Preservation
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• v.12 no.1
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• pp.28-35
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• 2005

The storage temperature significantly affected the microbiological quality of the chicken breast In the non-inadiated samples at $30^{\circ}C$, aerobic plate count (APC) and Echerichia coli count of the samples considerably increased during 3 days of storage and were eliminated by an irradiation at dose of 10 kGy or more. The APC and E coli count of the samples stored at $5^{\circ}C$ were reduced to below the limit of detection (< 2 log CFU/g) through the whole storage period by an irradiation at 5 kGy or mote. There was no significant difference in the TBA values between the non-inadiated and inadiated samples, which were not significantly higher in the irradiated samples than the non-inadiated samples during 2 weeks of storage at $5^{\circ}C$. According to the same-different test and acceptance test the sensory quality of the irradiated chicken breast was not significantly different from that of the non-inadiated sample even at 10 kGy. It is found that gamma irradiation is an effective tool to improve the quality of chicken breast in a group-meal service. It was also found that there was no evidence that an irradiation induced mutagenicity in the chicken breast meat.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.910-917
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• 2018

This paper describes the developments to improve the feeling and safety of the remote control system of unmanned vehicles. Generally, in the case of the remote control systems, a joystick-type device or a simple steering-wheel are used. There are many cases, in which there are operations without considering the feedback to users and driving feel. Recently, as the application area of the unmanned vehicles has been extended, the problems caused by not considering the feedback are emphasized. Therefore, the need for a force feedback-haptic control arises to solve these problems. In this study, the force feedback-haptic control algorithm considering the vehicle parameters is proposed. The vehicle parameters include first the state variables of dynamics, such as the body side-slip angle (${\beta}$) and yawrate (${\gamma}$), and second, the parameters representing the driving situations. Force feedback-haptic control technology consists of the algorithms for general and specific situations, and considers the situation transition process. To verify the algorithms, a simulator was constructed using the vehicle dynamics simulation tool with CAN communication environment. Using the simulator, the feasibility of the algorithms was verified in various scenarios.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.703-708
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• 2022

A detector module measuring the depth of interaction(DOI) was designed to improve the spatial resolution of positron emission tomography(PET). The scintillation pixel array consists of two layers, and a light guide is inserted between the layers to make the light generated through the gamma-ray event different for each layer. There are four light guides, and one light guide is designed to be coupled to a 2 × 2 array of scintillation pixels. The light generated from the top layer is moved to the photosensor with a wider distribution through the light guide, and the light generated from the bottom layer is incident on the photosensor with a narrower distribution than the top layer. When a flood image is reconstructed based on the signals obtained from the photosensor by different distributions, scintillation pixels are imaged at different positions for each layer. To verify this, a DETECT2000 simulation tool that simulates the behavior of light in a scintillator was used. By designing a scintillation pixel array, a detector consisting of a light guide and a photosensor, a gamma ray event was generated in all scintillation pixels to obtain a flood imgae. As a result, it was confirmed that the top and bottom layers were imaged at different positions and completely separated. When this detector is applied to PET, it is considered that image quality can be improved through imporved spatial resolution.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.438-442
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• 1997

Antisense oligonucleotide represents an interesting tool for selective inhibition of gene expression. However, their low efficiency of introduction within intact cells remains to be overcome. Antisense-$TGF{\beta}$ (25 mer) and antisense-$TGF{\beta}$ (18 mer) were used to study the cellular transport and biological function of antisense oligonucleotide in vitro. Since TGF and TNF play on important role in regulating the nitric oxide production from macrophages, the action of the above antisense oligonucleotides was easily monitored by the determination of nitrite. Poly-L-lysine, benzalkonium chloride and tetraphenylphosphonium chloride were used as polycations, which neutralize the negative charge of antisense oligonucleotide. The production of nitric oxide mediated by .gamma.-IFN in mouse peritoneal macrophage was increased by antisense-TGF.betha. in a dose-dependent manner. Antisense-$TGF{\beta}$ reduced the nitric oxide release from activated RAW 264.7 cells. Significant enhancement in the nitric oxide production was investigated by the cotreatment of poly-L-lysine with antisense-$TGF{\beta}$On the meanwhile, inhibition effect of antisense-$TGF{\beta}$ is not changed by the addition of poly-L-lysine. These results demonstrate that control of expression of $TGF{\beta}$ and TNF.alpha. gene is achieved using antisense technology and the cellular uptake of antisense oligonucleotide could be enhanced by ion-pairing.

• Journal of Korean Neurosurgical Society
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• v.51 no.5
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• pp.262-267
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• 2012

Objective : We aimed to investigate the correlation between the success of recanalization and a modified version of the Qureshi grading system in acute ischemic stroke patients. Methods : We retrospectively analyzed the intra-arterial thrombolysis (IAT) records of 37 patients who were evaluated by Thrombolysis in Myocardial Infarction (TIMI) and a modified version of the Qureshi grading systems as follows : 1) post-IAT Qureshi grade, 2) modified ${\Delta}$ Qureshi grade : pre-IAT group grade - post-IAT group grade (grade 1 : Qureshi grades 0-2 and grade 2 : Qureshi grade 3-5) and 3) ${\Delta}$ Qureshi grade (post-IAT Qureshi grade - pre-IAT Qureshi grade). Successful recanalization was defined as follows : 1) post-IAT TIMI grades 2 and 3, 2) post-IAT Qureshi grade 0-2, 3) modified ${\Delta}$ Qureshi grade=1, and 4) ${\Delta}$ Qureshi grade of ${\geq}2$ and/or post-IAT Qureshi grade=0. We investigated the correlation between the post-IAT TIMI grade and the modified Qureshi grade and also compared the various grading systems with modified Rankin Scale scores for evaluating the clinical outcome at 3 months. Results : The post-IAT Qureshi grade and ${\Delta}$ Qureshi grade and/or post-IAT Qureshi grade were significantly correlated with the TIMI grade (${\gamma}$=0.976 and, 0.942, respectively). Further, post-IAT Qureshi grade and ${\Delta}$ Qureshi grade and/or post-IAT Qureshi grade showed a significantly stronger association with clinical outcome than did the post-IAT TIMI grade (p=0.001 and, 0.000 vs. 0.083, respectively). Conclusion : Our preliminary results suggest that the modified Qureshi grading system is a useful tool for assessing the success of recanalization after IAT.

• Radiation Oncology Journal
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• v.24 no.2
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• pp.144-148
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• 2006

Trigeminal neuralgia is defined as an episodic electrical shock-like sensation in a dermatomal distribution of the trigeminal nerve. When medications fail to control pain, various procedures are used to attempt to control refractory pain. Of available procedures, stereotactic radiosurgery is the least invasive procedure and has been demonstrated to produce significant pain relief with minimal side effects. Recently, linear accelerators were introduced as a tool for radiosurgery of trigeminal neuralgia beneath the already accepted gamma unit. Author have experienced one case with trigeminal neuralgia treated with linear accelerator. The patient was treated with 85 Gy by means of 5 mm collimator directed to trigeminal nerve root entry zone. The patient obtained pain free without medication at 20 days after the procedure and remain pain free at 6 months after the procedure. He didn't experience facial numbness or other side effects.

• Reproductive and Developmental Biology
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• v.31 no.4
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• pp.241-248
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• 2007

Epigenetic modification dependent DNA methyltransferases (DNMTs) play an important role in tissue- and stage-specific gene regulation and normal mammalian development. In this study, we show that DNMTs are expressed at different levels during hematopoietic stem cell (HSC) differentiation to proerythrocytes. DNMT1, DNMT3A, and DNMT3B were highly expressed at day 7 after differentiation. We used specific siRNA as a tool to probe the relationship between the expression of DNMTs and erythropoietic differentiation. When introduced siRNA of DMNT1 and DMNT3b in human $CD34^+$ cells, these more differentiated into erythrocytes. This was confirmed by glycophorin A (GPA) positive cell analysis and globin gene expression. $GPA^+$ cells increased up to $20{\sim}30%$, and ${\gamma}$- and ${\epsilon}$-globin genes increased in siRNA transfected cells. Therefore, our data suggest that suppression of DNA methylation can affect positively differentiation of HSC and may contribute to expression of erythrocyte lineage genes including GPA and globins.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.884-888
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• 2009

Effect of citrus pectin oligosaccharides produced by irradiation was studied on the ability to improve lipid metabolism and hypercholesterolemia in mice fed high cholesterol diets. A total of 35 mice were divided into 5 groups and fed the following diets for 6 weeks: normal diet (C), 0.5% cholesterol (CH), 0.5% cholesterol+5% non-irradiated pectin (P), 0.5% cholesterol+5% irradiated pectin at 20 kGy (PIR), and 0.5% cholesterol+5% irradiated at 20 kGy and dialyzed (PIR-F). CH group had significantly higher serum triglycerides, total cholesterol, and low density lipoprotein (LDL)-cholesterol contents than pectin oligosaccharide-treated groups (p<0.05). Triglycerides and total cholesterol contents was the lowest in C and PIR-F and followed by PIR and P group, and CH group had significantly higher LDL-cholesterol. Serum high density lipoprotein (HDL)-cholesterol content in C group was not different from that in CH and P groups, but lower than that of PIR and PIR-F groups. These results suggest that pectin oligosaccharides produced by irradiation can reduce the levels of serum triglyceride, total cholesterol, and LDL-cholesterol in the blood of mice fed high-cholesterol diets and therefore, irradiation can be used as a tool to produce functional oligosaccharides from citrus pectin.