• Journal of the Korean Society of Radiology
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• v.5 no.1
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• pp.37-49
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• 2011

To examine the possible changes in the SNRs, CNRs, and ADC values for lumbar spines with metastasis based on the DW images before and after contrast agent injection taken from metastatic spinal cancer patients using a 1.5 T MR machine. The quantitative analysis revealed that in case of spinal cancer subjects, both SNRs and CNRs at all of those assessed locations significantly increased on the DWI after contrast agent injection compared to before, while on the ADC map images, SNRs significantly decreased. On the other hand, significantly decreased ADC values at all the assessed locations were found on the ADC map images. With reference to the normal group, significantly increased SNRs were found at all of the assessed locations on the DWI image after injection compared to before, while significantly decreased SNRs were found on the ADC map images. Also, significantly decreased ADC values at all the assessed locations were found on the ADC map images. For the qualitative analysis, after contrast agent injection, significantly increased signal intensities were found at the locations with spinal cancer on the DWI. In contrast, significantly decreased signal intensities were found on the ADC map images. The implication from the results showing that SNR and CNR significantly increased while ADC value significantly decreased at, above, and below the location of metastatic spinal cancer on DWI after contrast agent injection is that DWI obtained after contrast agent injection can be made available for wider application to vertebral disorders.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.39-42
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• 1999

Perfluoropolymers represent the ultimate resistance to hostile chemical environments and high service temperature, attributed to the presence of fluorine in the polymer backbone, i.e. to the high bond energy of C-F and C-C bonds of fluorocarbons. Copolymers of Tetrafluoroethylene (TEE) and 2, 2, 4Trifluoro-5Trifluorometoxy- 1, 3Dioxole (TTD), commercially known as HYFLON AD, are amorphous perfluoropolymers with glass transition temperature (Tg)higher than room temperature, showing a thermal decomposition temperature exceeding 40$0^{\circ}C$. These polymer systems are highly soluble in fluorinated solvents, with low solution viscosities. This property allows the preparation of self-supported and composite membranes with desired membrane thickness. Symmetric and asymmetric perfluoropolymer membranes, made with HYFLON AD, have been prepared and evaluated. Porous and not porous symmetric membranes have been obtained by solvent evaporation with various processing conditions. Asymmetric membranes have been prepared by th wet phase inversion method. Measure of contact angle to distilled water have been carried out. Figure 1 compares experimental results with those of other commercial membranes. Contact angles of about 120$^{\circ}$for our amorphous perfluoropolymer membranes demonstrate that they posses a high hydrophobic character. Measure of contact angles to hexandecane have been also carried out to evaluate the organophobic character. Rsults are reported in Figure 2. The observed strong organophobicity leads to excellent fouling resistance and inertness. Porous membranes with pore size between 30 and 80 nanometers have shown no permeation to water at pressures as high as 10 bars. However high permeation to gases, such as O2, N2 and CO2, and no selectivities were observed. Considering the porous structure of the membrane, this behavior was expected. In consideration of the above properties, possible useful uses in th field of gas- liquid separations are envisaged for these membranes. A particularly promising application is in the field of membrane contactors, equipments in which membranes are used to improve mass transfer coefficients in respect to traditional extraction and absorption processes. Gas permeation properties have been evaluated for asymmetric membranes and composite symmetric ones. Experimental permselectivity values, obtained at different pressure differences, to various single gases are reported in Tab. 1, 2 and 3. Experimental data have been compared with literature data obtained with membranes made with different amorphous perfluoropolymer systems, such as copolymers of Perfluoro2, 2dimethyl dioxole (PDD) and Tetrafluorethylene, commercialized by the Du Pont Company with the trade name of Teflon AF. An interesting linear relationship between permeability and the glass transition temperature of the polymer constituting the membrane has been observed. Results are descussed in terms of polymer chain structure, which affects the presence of voids at molecular scale and their size distribution. Molecular Dyanmics studies are in progress in order to support the understanding of these results. A modified Theodoru- Suter method provided by the Amorphous Cell module of InsightII/Discover was used to determine the chain packing. A completely amorphous polymer box of about 3.5 nm was considered. Last but not least the use of amorphous perfluoropolymer membranes appears to be ideal when separation processes have to be performed in hostile environments, i.e. high temperatures and aggressive non-aqueous media, such as chemicals and solvents. In these cases Hyflon AD membranes can exploit the outstanding resistance of perfluoropolymers.

• Investigative Magnetic Resonance Imaging
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• v.14 no.1
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• pp.31-40
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• 2010

Purpose : To compare the relative values of various fast breath-hold imaging sequences for superparamagnetic iron-oxide (SPIO)-enhanced hepatic MRI for the assessment of solid focal lesions with a 3T MRI unit. Materials and Methods : 102 consecutive patients with one or more solid malignant hepatic lesions were evaluated by spoiled gradient echo (GRE) sequences with three different echo times (2.4 msec [GRE_2.4], 5.8 msec [GRE_5.8], and 10 msec [GRE_10]) for $T2^*$-weighted imaging in addition to T2-weighted turbo spin echo (TSE) sequence following intravenous SPIO injection. Image qualities of the hepatic contour, vascular landmarks and artifacts were rated by two independent readers using a four-point scale. For quantitative analysis, contrast-to-noise ratio (CNR) was measured in 170 solid focal lesions larger than 1 cm (107 hepatocellular carcinomas, nine cholangiocarcinomas and 54 metastases). Results : GRE_5.8 showed the highest mean points for hepatic contour, vascular anatomy and imaging artifact presence among all of the subjected sequences (p<0.001) and was comparable (p=0.414) with GRE_10 with regard to lesion conspicuity. The mean CNRs were significantly higher (p<0.001) in the following order: GRE_10 ($24.4{\pm}14.5$), GRE_5.8 ($14.8{\pm}9.4$), TSE ($9.7{\pm}6.3$), and GRE_2.4 ($7.9{\pm}6.4$). The mean CNRs of CCCs and metastases were higher than those of HCCs for all imaging sequences (p<0.05). Conclusion : Regarding overall performances, GRE using a moderate echo time of 5.8 msec can provide the most reliable data among the various fast breath-hold SPIO-enhanced hepatic MRI sequences at 3T unit despite the lower CNR of GRE_5.8 compared to that of GRE_10.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.6
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• pp.29-34
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• 1978

It has been investigated that the elect of an wideband FDM-FM signal upon an M-ary coherent PSK (MCPSK) signal in an intersystem radio interference environment between analog and digital systems, which had not been discussed before and had been obscure. It is assumed that PSK and FM signal are adjacently allocated in same radio frequency band. And the symbol error performance of MCPSK signal with co-channel and adjacent channel interference from an FDM-FM signal is evaluated with considering the receiver noise. The numerical results for the theoretical symbol error rates of MCPSK system in the presence of Gaussian noise and co-channel or adjacent channel interference are given in graphical forms as the function of carrier-to-noise ratio (CNR), carrier-to-interference ratio (CIR) and normalized carrier separation between the desired PSK and interfering FM signal. The objective of this research is to find some optimal conditions for coexistence of analog and digital systems in an intersystem interference environment. The results we obtained here stress a possible utilization of them for designing the frequency allocation, bandwidth and power of PSK channel in the intersystem interference from an FDM-FM signall.

• Korean Journal of Digital Imaging in Medicine
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• v.14 no.1
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• pp.7-12
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• 2012

The purpose of this study was to examine usefulness of 3T equipment-based time-of-flight magnetic resonance angiography (3T-TOF MRA) by comparing standard technique (ST) with high resolution technique (HRT) in evaluation of cerebral blood vessel. The 3T-TOF MRA was performed for 31 patients who were suspected of having cerebrovascular disease from March to July 2010. For evaluation of cerebral blood vessel, classification was conducted randomly: group I that included vertebral artery and basilar artery, group II that ranged from 2.5cm before basin part of common carotid artery to basin part of internal and external carotid arteries and to genu part of internal carotid artery, group III that ranged from vertebral part of internal carotid artery to the first basin art of anterior and middle cerebral through education recognizes the importance of dose reduction and examine if their efforts and further reduce patient dose could achieve optimization of the medical exposure is considered.

• Transactions of the Society of Information Storage Systems
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• v.3 no.1
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• pp.34-39
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• 2007

Super-REsolution Near-field Structure (Super-RENS) 재생 현상을 모델링하고 재생 신호를 계산하여 실험 결과와 비교하였다. 약 2mW 내외의 높은 광 파워로 집광된 Spot 은 디스크 내의 상변화 물질인 GST 를 용융시키므로 집광 Spot 내에는 용융 영역과 비 용융 영역이 공존하게 되고 연속적 또는 불연속적인 경계를 이루게 된다. 이러한 열 효과로부터 기인하는 집광 Spot 내에서의 물질의 광학적 특성 변화와 변화 정도의 차이를 가정하였고 변화된 광학적 특성은 집광된 Spot 의 유효 크기를 줄어들게 함으로써 회절한계 이하의 정보를 재생 가능하게 한다. 계산은 FDTD 방법과 Scalar 방법을 병행하였다. FDTD 방법으로는 위와 같은 집광 Spot 내의 물질 굴절률 (n,k) 변화로부터 회절한계 이하의 정보가 재생 가능함과 CNR 문턱 현상을 확인하였고, Scalar 방법으로는 물질 굴절률을 직접 다루지 않고 굴절률 변화로부터 기인하는 광의 Amplitude 와 Phase 변화로부터 회절한계 이하의 정보가 재생 가능함을 확인하였다. 이 때 광의 Amplitude 와 Phase 변화를 모델링하기 위하여 지름, 위치, 반사율 변화량, 위상 변화량의 네가지 변수로 정의되는 광 마스크를 도입하였다. Scalar 방법을 이용하여 재생 RF 신호 등 다양한 Super-RENS 디스크의 신호를 계산 활용 할 수 있고 다음의 두가지 광학계에 대하여 계산과 실험으로 얻은 채널 특성 및 RF 신호를 비교하여 각각 오차평균 4.2%, 4.7%로 일치함을 확인하였다. 파장 659nm, NA=0.6, Min Pit Length=173nm ROM 디스크 System, 파장 405nm, NA=0.85 Min Mark Length=75nm WORM 디스크 System.

• Clinical Nutrition Research
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• v.6 no.3
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• pp.172-182
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• 2017

We investigated the association between dietary habits/food group consumption patterns and early risk of metabolic syndrome (MetS), a main cause for metabolic disease. Study participants were recruited from the health promotion center in Dong-A University Hospital and public advertisement. Study subjects (n = 243, 21-80 years) were categorized into three groups: Super-healthy (MetS risk factor [MetS RF] = 0, n = 111), MetS-risk carriers (MetS RF = 1-2, n = 96), and MetS (MetS $RF{\geq}3$, n = 27). Higher regularity in dietary habits (breakfast-everyday, regular eating time, non-frequent overeating, and non-frequent eating-out) was observed in the Super-healthy group than in the MetS-risk carriers, and particularly in the MetS subjects. The relationship between food group consumption patterns and MetS-risk related parameters were investigated with adjustment for confounding factors. Fruit consumption was positively associated with HDL-cholesterol, and tended to be negatively associated with waist circumference, triglyceride, LDL-cholesterol, and insulin resistance (IR). The consumption of low-fat meats and fish, and vegetables was negatively associated with hs-CRP. Specifically, the consumption of seafoods belonging to the low-fat fish was negatively associated with fasting glucose, hs-CRP, and interleukin (IL)-6. Anchovy/dried white baits consumption was negatively associated with fasting insulin and IR. Green-yellow vegetables consumption was negatively associated with fasting insulin, IR, and hs-CRP. On the other hand, sugars and fast-foods were positively associated with LDL-cholesterol. Additionally, fast-foods consumption was positively associated with hs-CRP and IL-6 levels. In conclusion, dietary habits/food group consumption patterns are closely associated with MetS-risk related parameters in Koreans. It may suggest useful information to educate people to properly select healthy foods for early prevention of MetS.

• Clinical Nutrition Research
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• v.12 no.2
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• pp.138-153
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• 2023

The prevalence of metabolic syndrome (MetS) and its cost are increasing due to lifestyle changes and aging. This study aimed to develop a deep neural network model for prediction and classification of MetS according to nutrient intake and other MetS-related factors. This study included 17,848 individuals aged 40-69 years from the Korea National Health and Nutrition Examination Survey (2013-2018). We set MetS (3-5 risk factors present) as the dependent variable and 52 MetS-related factors and nutrient intake variables as independent variables in a regression analysis. The analysis compared and analyzed model accuracy, precision and recall by conventional logistic regression, machine learning-based logistic regression and deep learning. The accuracy of train data was 81.2089, and the accuracy of test data was 81.1485 in a MetS classification and prediction model developed in this study. These accuracies were higher than those obtained by conventional logistic regression or machine learning-based logistic regression. Precision, recall, and F1-score also showed the high accuracy in the deep learning model. Blood alanine aminotransferase (β = 12.2035) level showed the highest regression coefficient followed by blood aspartate aminotransferase (β = 11.771) level, waist circumference (β = 10.8555), body mass index (β = 10.3842), and blood glycated hemoglobin (β = 10.1802) level. Fats (cholesterol [β = -2.0545] and saturated fatty acid [β = -2.0483]) showed high regression coefficients among nutrient intakes. The deep learning model for classification and prediction on MetS showed a higher accuracy than conventional logistic regression or machine learning-based logistic regression.

• Clinical Nutrition Research
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• v.12 no.2
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• pp.91-98
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• 2023

Adequate nutritional support is crucial in preventing complications and improving outcomes in critically ill patients. Extracorporeal membrane oxygenation (ECMO) is a mode of supportive care for patients with respiratory and/or cardiac failure. ECMO patients frequently exhibit a hypermetabolic state characterized by protein catabolism and insulin resistance, which can lead to malnutrition. Nutritional therapy is a vital component of intensive care, but its optimal administration for ECMO patients is unknown. This case report aims to provide insights into effective nutritional management for critically ill patients undergoing ECMO therapy. The patient was a 72-year-old male with a history of gastric and lung cancer who underwent a lobectomy complicated by bronchopleural fistula, postoperative bleeding, pneumonia, and acute respiratory distress syndrome (ARDS). The patient's nutritional status was assessed indicating a high risk of malnutrition, using the modified Nutrition Risk in the Critically Ill (mNUTRIC) Score. Nutritional support was administered based on the recommendations of European Society for Clinical Nutrition and Metabolism (ESPEN) and the American Society for Parenteral and Enteral Nutrition (ASPEN), with energy requirements set at 25-30 kcal/kg/d and protein requirements set at 1.2-2.0 g/kg/day. The patient received parenteral nutrition until the enteral nutrition target amount was reached, with zinc supplements for wound healing. The study highlights the need for further research on proactive and effective nutritional support for ECMO patients to improve compliance and prognosis.

• Clinical Nutrition Research
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• v.12 no.2
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• pp.99-115
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• 2023

Patients with colorectal cancer may experience symptoms such as diarrhea, nausea, and anorexia, during surgery and chemotherapy, which can increase the risk of malnutrition. In addition, dietary habits play a key role in the onset of colorectal cancer; therefore, it is necessary to improve dietary habits to prevent recurrence during treatment after diagnosis. In this study, a clinical nutritionist conducted 4 interviews for patients diagnosed with colorectal cancer and scheduled for colectomy: before surgery, after surgery, 1st chemotherapy, and 2nd chemotherapy, and provided nutrition care for each treatment course to determine its effects on nutrition status and disease prognosis. Significant weight loss but no decrease in muscle mass was observed during treatment. Body fat mass, although not statistically significant, showed a decreasing tendency. The percentage of people who responded 'yes' to the below items increased after compared to before receiving nutrition education: 'I eat meat or eggs more than 5 times a week,' 'I eat seafood at least three times a week,' 'I eat vegetables at every meal,' 'I eat fruits every day,' and 'I eat milk or dairy products every day.' These results indicate that the patients changed their dietary habit from a monotonous eating pattern to a pattern of consuming various food groups after receiving nutrition education. These results suggest that continuous nutrition care by clinical dietitians, according to the patient's treatment process, can help improve the patient's nutritional status and establish healthy eating habits.