• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.2
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• pp.79-89
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• 2009

The objective of this study was to find out the stable formulation of nano-emulsion containing high concentration of quercetin and to investigate the effect of an ethanol on the nano-emulsion prepared by POE (30) hydrogenated castor oil (HCO-30)/oil/quercetin/ethanol/water system. Nano-emulsion was prepared using emulsion inversion point (EIP) method as low-energy method plus homogenizer as high-energy method. To evaluate effect of ethanol and other components on the nano-emulsion, physical properties such as droplet size, morphology, and size distribution were determined. The optimal quercetin concentration was 0.2 % on the nano-emulsion. The droplet diameter was below 300 nm at the HCO-30 concentration below 2.00 %. Nano-emmulsion containing 4.75 % HCO-30 was the most stable and its mean droplet size was 172.40 nm. Finally, the size of nano-emulsion containing 4.00 % ethanol was 128.15 nm and size distribution was also narrow. The results showed that the breakdown process of this nano-emulsion could be attributed to Ostwald ripening. This study about effect of ethanol on the nano-emulsion showed that loading capacity of drug could be increased by using a small amount of ethanol. As prepared stable nano-emulsion, this study showed that these results could be applied to pharmaceutics, cosmetic including skin-care products, perfume and etc.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.273-273
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• 2013

Recently, Point-of-care (POC) testing microdevices enable to do the patient monitoring, drug screening, pathogen detection in the outside of hospital. Immunochromatographic strip (ICS) is one of the diagnostic technologies which are widely applied to POC detection. Relatively low cost, simplicity to use, easy interpretations of the diagnostic results and high stability under any circumstances are representative advantages of POC diagnosis. It would provide colorimetric results more conveniently, if the genetic analysis microsystem incorporates the ICS as a detector part. In this work, we develop a reverse transcriptase-polymerase chain reaction (RT-PCR) microfluidic device integrated with a ROSGENE strip for colorimetric influenza H1N1 virus detection. The integrated RT-PCR- ROSGENE device is consist of four functional units which are a pneumatic micropump for sample loading, 2 ${\mu}L$ volume RT-PCR chamber for target gene amplification, a resistance temperature detector (RTD) electrode for temperature control, and a ROSGENE strip for target gene detection. The device was fabricated by combining four layers: First wafer is for RTD microfabrication, the second wafer is for PCR chamber at the bottom and micropump channel on the top, the third is the monolithic PDMS, and the fourth is the manifold for micropump operation. The RT-PCR was performed with subtype specific forward and reverse primers which were labeled with Texas-red, serving as a fluorescent hapten. A biotin-dUTP was used to insert biotin moieties in the PCR amplicons, during the RT-PCR. The RT-PCR amplicons were loaded in the sample application area, and they were conjugated with Au NP-labeled hapten-antibody. The test band embedded with streptavidins captures the biotin labeled amplicons and we can see violet colorimetric signals if the target gene was amplified with the control line. The off-chip RT-PCR amplicons of the influenza H1N1 virus were analyzed with a ROSGENE strip in comparison with an agarose gel electrophoresis. The intensities of test line was proportional to the template quantity and the detection sensitivity of the strip was better than that of the agarose gel. The test band of the ROSGENE strip could be observed with only 10 copies of a RNA template by the naked eyes. For the on-chip RT-PCR-ROSGENE experiments, a RT-PCR cocktail was injected into the chamber from the inlet reservoir to the waste outlet by the micro-pump actuation. After filling without bubbles inside the chamber, a RT-PCR thermal cycling was executed for 2 hours with all the microvalves closed to isolate the PCR chamber. After thermal cycling, the RT-PCR product was delivered to the attached ROSGENE strip through the outlet reservoir. After dropping 40 ${\mu}L$ of an eluant buffer at the end of the strip, the violet test line was detected as a H1N1 virus indicator, while the negative experiment only revealed a control line and while the positive experiment a control and a test line was appeared.

• Korean Journal of Community Nutrition
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• v.27 no.2
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• pp.146-157
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• 2022

Objectives: This study aimed to develop and assess the content validity and internal consistency of a questionnaire on the feasibility of mobile dietary self-monitoring applications. Methods: We developed a feasibility questionnaire to assess the overall usage, convenience, usefulness, and satisfaction of mobile dietary applications. The initial draft of the questionnaire contained 17 items with yes/no, multiple-choice, and open-ended questions and 52 items on 5-point Likert scales. To validate the content, ten experts evaluated the relevance of the items for each subscale using a 5-point scale. We calculated the item-level content validity index (I-CVI) and scale-level content validity index (S-CVI). A total of 102 adults answered the questionnaires which reflected the experts' reviews. We conducted an exploratory factor analysis to determine the underlying structure of responses and categorized convenience, usefulness, and satisfaction. We also calculated Cronbach's alpha coefficient to examine the internal consistency of items in each subscale. Results: The S-CVI score of the items was 0.86, and we removed items with an I-CVI score of < 0.80. We combined, revised, or separated some remaining items and added one item as per the experts' comments. As a result, we included 16 items about overall usage and 42 sub-questions. Based on the responses of the 102 adults, we performed exploratory factor analysis using the principal axis method. We retained items with a factor loading of > 0.40, resulting in a final set of 35 questions (convenience: 15, usefulness: 12, satisfaction: 8 items). The Cronbach's alpha values of the three scales were 0.93, 0.91, and 0.91 for 1) usefulness, 2) convenience, and 3) satisfaction, respectively. Conclusions: We developed a feasibility questionnaire for mobile dietary self-monitoring applications and examined its content validity and internal consistency. Our questionnaire has the potential to measure the feasibility of mobile dietary self-monitoring applications.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.43-50
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• 2007

Liposomes having particle size from several tens to hundreds nanometers are efficient carriers for injectable drug delivery. Enhancement of liposome stability in bloodstream has been studied because of its relatively short circulation time and fast clearance from human body by reticuloendothelial system (RES) in blood vessel. In this study, new disaccharide-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) derivatives in which lactose or sucrose as the disaccharide molecule was conjugated covalently to DSPE were synthesized. Liposomes of which surface had disaccharide molecules were prepared by incorporating the disaccharide-DSPE into liposomes as one of their lipid components. Particle size of the prepared liposomes was approximately 100 nm. The liposomes of which surface were modified with the disaccharide-DSPE showed -25 mV of zeta potential value due to the presence of hydroxyl groups on their surface, while the unmodified control liposomes showed -10 mV of zeta potential value. Loading efficiency of model drug, doxorubicin, into liposomes was about 90%. Stability of the disaccharide-modified liposomes in vitro was evaluated by monitoring the amount of protein adsorption and particle size of the liposomes in serum. Disaccharide-modified liposomes were more stable in serum than unmodified control liposomes or polyethyleneglycol (PEG)-modified liposomes due to less adsorption of serum protein and hence less increase of their particle size. The liposomes of which surface was modified with disaccharide-DSPE conjugate can be used as long-circulating carriers for drugs having high toxicity or short half-life time due to their enhanced stability in blood circulatory system.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.15 no.2
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• pp.143-151
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• 2004

Objectives : Child and adolescent onset obsessive compulsive disorder(C-OCD) is known to be associated with poor drug response, high comorbid rate and strong genetic tendencies. Till now studies for C-OCD have been very rare in Korea. We conducted this study to investigate the informations about clinical features, familial psychiatric loading, treatment profiles and course of server C-OCD from the retrospective analysis of inpatient data of Seoul National University Children's Hospital. Method : Retrospective chart review and data analysis was performed. Twenty(male 16 : female 4) patients with final C-OCD diagnosis by DSM-IV at discharge from 1994 to 2002 were found and their medical chart, psychological data, family interview data and nursing reports were collected and analyzed. Results : 1) The sex ratio of C-OCD was male dominant(4:1). 2) Phenomenological, most common obsession was pathologic doubt, contamination fear, followed by aggressive obsession, need for symmetry, sexual obsession, most common compulsion was checking and washing, followed by breathing, movement, symmetry, repetitive asking, hoarding, mental compulsion. 3) Most common comorbid diagnosis was depression. Other axis-I diagnosis associated OCD were anxiety disorder, tic disorder, conduct and oppositional defiant disorder and psychosis. 4) Regarding psychiatric familial loadings, 17 patients(85%) had relatives with psychiatric disorders, OC-spectrum disorders(OCD or OCPD) were found in 9 patients(45%). 5) The majority of patients(75%) have received SSRI and antipsychotics treatment. The response rate above 'moderate improved" by CGI was 75%. 6) During follow-up period in outpatient clinic, five patients(25%) showed continuous complete remission, 10 patients (50%) did residual symptoms with chronic course. Conclusion : This seems to be the first systemic investigation of severe pediatric OCD patients in Korea. The children & adolescents with severe OCD in inpatient-setting showed the high comorbid rate, familial psychiatric loading, and combined pharmacotherapy with antipsychotics, As for symptoms, high rate of aggressive-sexual obsession and atypical compulsions like breathing and moving was reported in this study. Severe pediatric OCD patients, however, responded well to the combined SSRI and antipsychotics regimen.