• Journal of radiological science and technology
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• 제39권1호
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• pp.71-79
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• 2016

The purpose of this study is computed tomography contrast agent at low concentrations and low tube voltage technique to evaluate the usefulness on the phantom image. By varying the degree of mixture by the contrast medium concentration it was inserted in phantom. It was taken by changing the tube voltage and tube current step by step, and to evaluate the dose and the CT value obtained from the phantom image. As a result, low-contrast, low tube voltage(300 mgI/ml, 100 kV) was reduced by an average 21%(CTDIvol; computed tomography dose indexvol) more standard condition(350 mgI/ml, 120 kV). SNR was increased at all depths of the phantom, respectively 1:10 and 1:20(by diluting a contrast agent and normal saline) 12.2(26%) 6.2(17%). CNR was increased at all depths of the phantom, respectively 1:10 and 1:20(by diluting a contrast agent and normal saline) 11.5(32%), 6.3(26%). Research work on the CT scan is necessary in a variety of studies on the low contrast concentration and low tube voltage techniques for dose reduction and reducing of side effects the contrast agent.

• 전기의세계
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• 제34권9호
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• pp.537-540
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• 1985

인체에 발생하는 여러 질환을 진단 및 치료하고 예후를 결정하는데 혈관의 분포 및 그 상태를 관찰하는 것은 극히 중요하다. 형관조영술의 진단적 기치 및 그 임상적 응용은 1950년대 부터 널리 인정되고 있다. 다만 조영제 주입에는 동맥의 천자 및 도관(Catheter)삽입이라는 비교적 침습적 방법에 의존하여 왔다. 최근 Computer의 도입으로 대표되는 전자기술의 발전 등으로 혈관 특히 동맥의 저농도 조영상을 전산처리로서 숫자화하여 증강, 가산 또는 감산시키는 기법이 개발되어 1970년대 후반에 이르러 임상적으로 응용되게 되었다. 이러한 전산화 감산 형과조영술(Digital Subtraction Angiography : DAS)은 종래의 혈관조영술의 기본 수기에 전산 시스템을 복합시킨 것으로 그 임상적 효과는 매우 큰 것이다.

• Progress in Medical Physics
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• 제16권4호
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• pp.192-201
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• 2005

Experiments and simulation were done to study the impact of contrast agent when CT scan was used to attenuation correction for PET Images in PET/CT system. Whole body phantom was imaged with various concentration of iodine-based contrast agent using CT. Mathematical emission and transmission density map with liver were made to simulate for whole body FDG Imaging. A variety of factors were estimated, including non-uniform enhancement of contrast agent, concentration and distribution size of contrast agent, noise level, image resolution, reconstruction algorithm, hypo-attenuation of contrast agent, and different time phases for contrast agent. Experimental studies showed that Hounsfield unit depends on the concentration of contrast agent and tube voltage. From the simulation data, contrast agents Introduced artifacts and degraded image quality on the attenuation-corrected PET images. The severity of these effects depends on a variety of factors, including the concentration and distribution size of contrast agent, the noise levels, and the Image resolution. These results Indicated that the impact of contrast agents should be considered with a full understanding of their potential problems in clinical PET/CT images.

• Nuclear Medicine and Molecular Imaging
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• 제40권5호
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• pp.257-262
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• 2006

Purpose: The standard protocol using large volume of oral contrast media may cause gastrointestinal discomfort and contrast-related artifacts in PET/CT. The aim of this study was to evaluate the usefulness of low dose oral contrast in $^{18}F-FDG$ PET/CT. Materials and Methods: We retrospectively reviewed the whole-body PET/CT images in a total of 435 patients. About 200 ml of oval contrast agent (barium sulfate) was administered immediately before injection of $^{18}F-FDG$. The FDG uptake of intestines was analyzed by visual and semi- quantitative method on transaxial, coronal and saggital planes. Results: Seventy (16%, 113 sites) of 435 images showed high FDG uptake (peak SUV > 4); 50 (74%, 84 sites) with diffuse and 20 (15%, 29 sites) with focal uptake. The most commonly delivered site of oral contrast media was small bowel (n=27, 39%). On PET/CT images, FDG uptake coexisted with oral contrast media in 26 patients (54%, 38 sites) with diffuse pattern and 9 (45%, 9 sites) with focal pattern, and by sites, those were 38 (45%) and 9 (31%), respectively. In small bowel regions, the proportion of coexistence reached as high as 61% (29/47 sites). A visual analysis of available non-attenuation corrected PET images of 27 matched regions revealed no contrast-related artifact. Conclusion: We concluded that the application of low dose contrast media could be helpful in the evaluation of abdominal uptake in the FDG PET/CT image.

• Journal of the Korean Applied Science and Technology
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• 제30권1호
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• pp.88-95
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• 2013

This study attempts to capture the low level carbon dioxide from indoor spaces using a granular activated carbon (WSC-470) which was modified with primary monoethanolamine. Adsorption capacity of the prepared adsorbents was evaluated for pure $CO_2$ flow and 3000 ppm as a function of MEA concentration and solvents such as distilled water, ethanol and methanol. The AC based adsorbents then were characterized in terms of pore structure by BET and chemical functionalities by XPS. While high concentration of MEA reduced specific surface area, porosity and micro pores, nitrogen content which can enhance the surface basicity was increased. The maximum adsorption capacity decreased comparing to the initial AC pellets, whilst the potential of selective adsorption amount at low level $CO_2$ was increased at 45% (0.73 mmol/g).

• Applied Biological Chemistry
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• 제46권4호
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• pp.317-322
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• 2003

Changes of physicochemical properties during the preparation of persimmon pickles were investigated. The salinity in persimmon pickles increased during storage time $(0{\sim}50\;days)$ with soy sauce and soy paste. When the fermented soy sauce and soy paste was added to the soaking solution with $80{\sim}100%$, the salinity increased more rapidly. The hardness of persimmon pickles with soy sauce and soy paste was slightly increased up to the 20 or 30th day of storage and then decreased. L value of persimmon pickles was gradually decreased, but a and b value were slightly increased. The concentration of soluble tannin in persimmon pickles was slightly decreased down to the 20th day of storage and then decreased rapidly. The activities of polygalacturonase and pectinesterase as softening enzyme in persimmon pickles with soy sauce and soy paste increased during storage time $(0{\sim}50\;days)$ and enzyme activity was inhibited by high concentration of soaking solution.

• Journal of Applied Biological Chemistry
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• 제60권2호
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• pp.119-124
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• 2017

The extracted phenolic compounds from Pinus densiflora root were examined biological activities for beauty food. The tyrosinase inhibitory activity which was related to skin-whitening was observed. The tyrosinase inhibitory activity was confirmed to be 92% in ethanol extract at $50{\mu}g/mL$ phenolic. The elastase and collagenase inhibitory activity as anti-wrinkle effect were showed 61 and 78% in ethanol extract at $200{\mu}g/mL$ phenolic, respectively. Astringent effect of ethanol extract was showed to be 82% at $50{\mu}g/mL$ phenolic. Hyaluronidase inhibitory activity of ethanol extract as anti-inflammation effect was confirmed to be 94% of inhibition at $200{\mu}g/mL$ phenolic. These results demonstrated that isolated phenolic compounds from P. densiflora root could be expected to use as a functional cosmetic materials.

• Journal of the Korean Applied Science and Technology
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• 제29권1호
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• pp.1-12
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• 2012

In this study, $CO_2$ adsorbent was developed for removing low concentration of $CO_2$ in multiple-use facilities. The efficiency of the adsorbent which was improved selective $CO_2$ adsorption capabilities was evaluated. The pellet type adsorbent was modified from a commercial zeolite with mixing LiOH, binder, additives, and $H_2O$. Column tests showed over 90 % of $CO_2$ was adsorbed within 400min. Chamber tests including batch and continuous types were performed for evaluating the adsorbent module. By batch tests, it was evaluated that about 92% of $CO_2$ was removed within 30 min. By continuous tests, 70% of $CO_2$ was removed within 30 min. It was analyzed that over 2,500 ppm of $CO_2$ was continuously removed as shown chamber tests. The reproducibility tests repeatedly performed for 15 days shows that over 1,000 ppm of $CO_2$ was continuously removed. Adsorption capacity of the developed adsorbent was 5.0mmol $CO_2/g$ adsorbent which was analyzed by TGA. It was estimated that the modified adsorbent was applicable to low $CO_2$ concentration and low temperature of indoor environment.

• Food Science and Preservation
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• 제22권3호
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• pp.335-344
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• 2015

The objective of this study was to determine the rheological characteristics and sensory evaluation of yanggaeng by using the functional properties of Momordica charantia. Dried Momordica charantia was roasted at $180^{\circ}C$ to remove its bitter taste. The results of the study were as follows : The phenolic compound of Momordica charantia was $6.30{\pm}0.17mg/g$ in water extracts, which was the highest extractive rate. The anti-oxidant activity of non-roasted and roasted samples was determined in various phenolic concentrations at $50{\sim}200{\mu}g/mL$. The DPPH activities of non-roasted and roasted Momordica charantia water and ethanol extracts were 74.06~92.71% and 86.06~94.07%, respectively. The ABTS were 36.26~98.03% and 67.02~99.60% in water and ethanol extracts, respectively. The anti-oxidant protection factor of water and ethanol extracts were 2.19~2.25 PF and 2.20~2.36 PF respectively, and TBARS were 13.81~40.97% and 23.32~82.47%, respectively. The anti-oxidant activity of ethanol extracts was higher than that of water extracts at low phenolics concentration of $50{\mu}g/mL$, while the roasted sample was higher than the sample that was not roasted. The ${\alpha}$-glucosidase inhibition activity of non-roasted Momordica charantia ethanol extracts was higher than that of water extracts, showing that there were increasing pattern depending on the increases in the phenolics concentration of Momordica charantia. The texture, such as hardness, springiness, cohesiveness, chewiness and color changed in proportion to the concentration of Momordica charantia powder. Moreover sensory characteristics, such as color, flavor, taste, texture and overall acceptability of the non-roasted sample changed in proportion to the concentration of Momordica charantia powder. However, in the roasted sample, the sensory characteristics was improved at a lower concentration (below 1%). Thus, when the yanggang was prepared by Momordica charantia powder as a minor ingredient, it would be desirable to add it after roasting, in consideration of its functional and sensory properties, and at appropriate concentration on below 1%.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제33권5호
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• pp.393-398
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• 2000

To extend utilization of alginate from the sea tangle, Laminaria japonicus, depolymerized alginates (HAG-10, average molecular weight 10,000; HAC-50, average molecular weight 50,000; HAG-100, average molecular weight 100,000) were obtained by hydrolysis of alginate by heating at $12^{\circ}C$. The effects of each depolymerized alginate on excretion of cholesterol, glucose and namium in rats were investigated. The total excretion rate (${\%}$) of cholesterol and cadmium was the highest in rats administered with HAG-50, The rate was $45.81{\%} and 59.02{\%} with HAG-50$. It was high in the order of $45.78{\%} and 56.05{\%}$ in HAG-100, $41.28{\%}$ and $55.96{\%}$ in alginate, and $32.11{\%} and 44.92{\%} in HAC-10$, respectively. In the case of HAG-50, it significantly (p<0.01) prevented the serum glucose level of rats from rising within 30 min and 60 min after glucose loading or administration among all the samples, but it had no particular effects on the serum insulin level. In conclusion, it was suggested that HAG-50, in which the alginate had a decreased molecular weight, while still retaining its desirable functions as a dietary fiber, was effective in excretion of harmful substances, such as cadmium and cholesterol, and in lowering glucose activities in serum of rats.