Integrated-optic current sensors with a multimode interference waveguide device.

Optical current sensors based on polarization-rotated reflection interferometry are demonstrated using polymeric integrated optics and various functional optical waveguide devices. Interferometric sensors normally require bias feedback control for maintaining the operating point, which increases the cost. In order to resolve this constraint of feedback control, a multimode interference (MMI) waveguide device is integrated onto the current-sensor optical chip in this work. From the multiple outputs of the MMI, a 90° phase-shifted transfer function is obtained. Using passive quadrature demodulation, we demonstrate that the sensor could maintain the output signal regardless of the drift in the operating bias-point.

Electrorheology of graphene oxide.

Novel polarizable graphene oxide (GO) particles with oxidized groups on their edge and basal planes were prepared by a modified Hummers method, and their electro-responsive electrorheological (ER) characteristics when dispersed in silicone oil were examined with and without an electric field applied. The fibrillation phenomenon of this GO-based electro-responsive fluid was also observed via an optical microscope under an applied electric field. Both flow curves and dielectric spectra of the ER fluid were measured using a rotational rheometer and a LCR meter, respectively. Its viscoelastic properties of both storage and loss moduli were also examined using a vertical oscillation rheometer equipped with a high voltage generator, finding that the GO-based smart ER system behaves as a viscoelastic material under an applied electric field.

Catalytic pyrolysis of oil fractions separated from food waste leachate over nanoporous acid catalysts.

Oil fractions, separated from food waste leachate, can be used as an energy source. Especially, high quality oil can be obtained by catalytic cracking. In this study, nanoporous catalysts such as Al-MCM-41 and mesoporous MFI type zeolite were applied to the catalytic cracking of oil fractions using the pyrolysis gas chromatography/mass spectrometry. Mesoporous MFI type zeolite showed better textural porosity than Al-MCM-41. In addition, mesoporous MFI type zeolite had strong Brönsted acidity while Al-MCM-41 had weak acidity. Significant amount of acid components in the food waste oil fractions were converted to mainly oxygenates and aromatics. As a result of its well-defined nanopores and strong acidity, the use of a mesoporous MFI type zeolite produced large amounts of gaseous and aromatic compounds. High yields of hydrocarbons within the gasoline range were also obtained in the case of mesoporous MFI type zeolite, whereas the use of Al-MCM-41, which exhibits relatively weak acidity, resulted in high yields of oxygenates and diesel range hydrocarbons.

Catalytic upgrading of oil fractions separated from food waste leachate.

In this work, catalytic cracking of biomass waste oil fractions separated from food waste leachate was performed using microporous catalysts, such as HY, HZSM-5 and mesoporous Al-MCM-48. The experiments were carried out using pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) to allow the direct analysis of the pyrolytic products. Most acidic components, especially oleic acid, contained in the food waste oil fractions were converted to valuable products, such as oxygenates, hydrocarbons and aromatics. High yields of hydrocarbons within the gasoline-range were obtained when microporous catalysts were used; whereas, the use of Al-MCM-48, which exhibits relatively weak acidity, resulted in high yields of oxygenated and diesel-range hydrocarbons. The HZSM-5 catalyst produced a higher amount of valuable mono aromatics due to its strong acidity and shape selectivity. Especially, the addition of gallium (Ga) to HZSM-5 significantly increased the aromatics content.

Implementation of Medical Information Exchange System Based on EHR Standard.

OBJECTIVES: To develop effective ways of sharing patients' medical information, we developed a new medical information exchange system (MIES) based on a registry server, which enabled us to exchange different types of data generated by various systems. METHODS: To assure that patient's medical information can be effectively exchanged under different system environments, we adopted the standardized data transfer methods and terminologies suggested by the Center for Interoperable Electronic Healthcare Record (CIEHR) of Korea in order to guarantee interoperability. Regarding information security, MIES followed the security guidelines suggested by the CIEHR of Korea. This study aimed to develop essential security systems for the implementation of online services, such as encryption of communication, server security, database security, protection against hacking, contents, and network security. RESULTS: The registry server managed information exchange as well as the registration information of the clinical document architecture (CDA) documents, and the CDA Transfer Server was used to locate and transmit the proper CDA document from the relevant repository. The CDA viewer showed the CDA documents via connection with the information systems of related hospitals. CONCLUSIONS: This research chooses transfer items and defines document standards that follow CDA standards, such that exchange of CDA documents between different systems became possible through ebXML. The proposed MIES was designed as an independent central registry server model in order to guarantee the essential security of patients' medical information.

Prevalence of diabetes mellitus in the elderly of Namwon County, South Korea.

BACKGROUND: Ethnic and geographic differences exist in the prevalence of diabetes mellitus which has increased dramatically in South Korea. A few community-based epidemiologic studies with oral glucose tolerance test were performed in South Korea. The purpose of this study was to determine the prevalence of diabetes mellitus by the World Health Organization (WHO) and the American Diabetic Association (ADA) diagnostic criteria and to investigate their associated risk factors. Also, we compared and analyzed the characteristics of Koreans by WHO and ADA diagnostic criteria. METHODS: Between March 22, 1999 and July 14, 1999, a random sampling of 1,445 residents over 40 years of age in five villages (3 myons and 2 dongs) in Namwon City. Chollabuk-do Province, South Korea was carried out. WHO and ADA diagnostic criteria were used for the prevalence of DM, IGT and IFG. The associated factors of subjects were analyzed. RESULTS: After age adjustment for the population projection of Korea (1999), the prevalence of DM and IGT was 13.7% and 13.8%, respectively, by WHO criteria, while the prevalence of DM, IGT and IFG was 15.8%, 12.8% and 5.7%, respectively, by ADA criteria, and the previous diagnosed diabetics were 5.8% in 665 adults over 40 years of age in the Namwon area. The age-adjusted prevalence of previously diagnosed diabetics was 5.8%. When the subjects classified by both criteria were compared, the level of agreement between WHO and ADA diagnostic criteria, except IFG, was very high (kappa = 0.94; p < 0.001). The ROC curve analysis determined FSG of 114.5 mg/dL (6.4 mmol/L) to yield optimal sensitivity and specificity corresponding to a PP2SG 200 mg/dL (11.1 mmol/L). The prevalence of DM and IGT with ADA diagnostic criteria rose with increasing age (p < 0.05). The body mass index was mean 23.8 +/- 3.4 in all the subjects, 23.75 +/- 3.46 in NGT group and 23.67 +/- 3.16 in DM group, but the differences in the prevalence of DM, IGT and IFG by BMI were not significant. The prevalence of DM rose significantly with the increase in the waist-hip ratio (p < 0.05). The prevalence of DM significantly increased in subjects by increases in blood pressure, and triglyceride and the relative risk in the prevalence of DM was significantly high with dyslipidemia (Odds ratio 2.29, 95% CI: 1.16-3.49). CONCLUSION: The prevalence of Diabetes Mellitus in the population over 40 years of age in Namwon City. South Korea remarkably increased compared with the 1970s and 1980s and was similar to that of the West. Ethnic differences in obesity of normal, DM and IGT subjects and in the effect on the prevalence of DM may exist in the Korean population, but they were not significant. As there is a limit in number, it is considered that a general population-based epidemiologic study on a large scale is required to investigate ethnic and geographic differences for the risk factors of DM in South Korea. The level of agreement, except IFG, by WHO and ADA diagnostic criteria was high, which indicates that these results may show that not only fasting serum glucose but also postprandial 2-h serum glucose are important for diagnosing diabetes in Korean.