Magnetic resonance characterization of gadolinium-based contrast agents

Several magnetic resonance methods have been used for characterizing gadolinium-based contrast agents in NMR Imaging in this thesis. Many Gd-based contrast agents were studied including Gd DTPA(dimethylenetriaminepentaacetic acid). The zero field splitting energies and g values of Gd complexes were obtained in frozen solutions by the EPR technique. Solvent structures of Gd-based contrast agents were studied by the ESE(Electron Spin Echo) method. Analysis of \sp2H-ESEEM of Gd TTHA(trimethylenetetraaminehexaacetic acid) demonstrated the existence of the second sphere water. The distance between \sp2H-Gd, a\sb{\rm iso}, and quadrupolar coupling constants were obtained by computer simulations of \sp2H-ESEEM of Gd complexes in frozen solutions. Water exchange times between the Gd complexes and bulk water were studied by O-17 NMR. However, it was found that the direct application of the Merbach method to the Gd-based contrast agent system showed some limitations. NMRD(Nuclear Magnetic Resonance Dispersion) studies provided useful information when combined with many other techniques. Data from NMRD simulations were well correlated with ones from EPR, ESEEM, and O-17 NMR. As a result, the combination of several techniques made NMRD analysis more reliable.In the last chapter, the results of low osmolar Gd-based contrast agents studies are described. NMRD measurements were done in water and human plasma. Some of the Gd complexes showed binding behavior with plasma proteins, especially albumin. This binding affinity seems to be varied depending on the balance between the hydrophilic and lipophilic groups in one compound

Environmental tobacco smoke and children's health

Passive exposure to tobacco smoke significantly contributes to morbidity and mortality in children. Children, in particular, seem to be the most susceptible population to the harmful effects of environmental tobacco smoke (ETS). Paternal smoking inside the home leads to significant maternal and fetal exposure to ETS and may subsequently affect fetal health. ETS has been associated with adverse effects on pediatric health, including preterm birth, intrauterine growth retardation, perinatal mortality, respiratory illness, neurobehavioral problems, and decreased performance in school. A valid estimation of the risks associated with tobacco exposure depends on accurate measurement. Nicotine and its major metabolite, cotinine, are commonly used as smoking biomarkers, and their levels can be determined in various biological specimens such as blood, saliva, and urine. Recently, hair analysis was found to be a convenient, noninvasive technique for detecting the presence of nicotine exposure. Because nicotine/cotinine accumulates in hair during hair growth, it is a unique measure of long-term, cumulative exposure to tobacco smoke. Although smoking ban policies result in considerable reductions in ETS exposure, children are still exposed significantly to tobacco smoke not only in their homes but also in schools, restaurants, child-care settings, cars, buses, and other public places. Therefore, more effective strategies and public policies to protect preschool children from ETS should be consolidated

The Origin of Star Formation in Early-type Galaxies Inferred from Spatially Resolved Spectroscopy

We investigate the origin of star formation activity in early-type galaxies with current star formation using spatially resolved spectroscopic data from the Mapping Nearby Galaxies at APO (MaNGA) in the Sloan Digital Sky Survey (SDSS). We first identify star-forming early-type galaxies from the SDSS sample, which are morphologically early-type but show current star formation activity in their optical spectra. We then construct comparison samples with different combinations of star formation activity and morphology, which include star-forming late-type galaxies, quiescent early-type galaxies and quiescent late-type galaxies. Our analysis of the optical spectra reveals that the star-forming early-type galaxies have two distinctive episodes of star formation, which is similar to late-type galaxies but different from quiescent early-type galaxies with a single star formation episode. Star-forming early-type galaxies have properties in common with star-forming late-type galaxies, which include stellar population, gas and dust content, mass and environment. However, the physical properties of star-forming early-type galaxies derived from spatially resolved spectroscopy differ from those of star-forming late-type galaxies in the sense that the gas in star-forming early-type galaxies is more concentrated than their stars, and is often kinematically misaligned with stars. The age gradient of star-forming early-type galaxies also differs from those of star-forming late-type galaxies. Our findings suggest that the current star formation in star-forming early-type galaxies has an external origin including galaxy mergers or accretion gas from the cosmic web.Comment: 19 pages, 12 figures, Accepted for publication in Ap

Influence of mixed alkali oxides on some melt properties of TV screen glass

The influence of K2O/R2O (R2O = Na2O+K2O) on some melt properties was studied in alkali-alkaline earth-silicate TV screen glasses. Viscosity, surface tension, electrical resistivity, volatilization and devitrification of glass melts were determined. No mixed alkali effect was observed in viscosity, surface tension and liquidus temperature. They showed a linear behavior with increase of K2O/R2O. On the other hand, electrical resistivity and weight loss by volatilization showed a strong mixed alkali effect against relative alkali concentration. According to the dependence of viscosity, electrical resistivity and volatilization on K2O/R2O, the slope change of those properties took place at K2O/R2O = 0.4 to ≈ 0.5. The compositional dependence of viscosity, surface tension and liquidus temperature was discussed in terms of field strength, polarizability and material diffusion, respectively. Α correlation was also discussed between the dependence of properties on K2O/R2O and the production process of TV screen glass. In conclusion, from the viewpoint of both production and application of TV glasses it was suggested that the mole fraction of K2O/R2O should lie between 0.2 and 0.5

Removal of Particulate Matter in a Tubular Wet Electrostatic Precipitator Using a Water Collection Electrode

As one of the effective control devices of air pollutants, the wet electrostatic precipitator (ESP) is an effective technique to eliminate acid mist and fine particles that are re-entrained in a collection electrode. However, its collection efficiency can deteriorate, as its operation is subject to water-induced corrosion of the collection electrode. To overcome this drawback, we modified the wet ESP system with the installation of a PVC dust precipitator wherein water is supplied as a replacement of the collection electrode. With this modification, we were able to construct a compact wet ESP with a small specific collection area (SCA, 0.83 m2/(m3/min)) that can acquire a high collection efficiency of fine particles (99.7%)

A Study on the Flora of 15 Islands in the Western Sea of Jeollanamdo Province, Korea

AbstractThis study aims to investigate the flora of 15 islands in Yeonggwang, Shinan, and Mokpo of the Jeollanamdo province and the distribution of major plants in order to use the results as fundamental data for studies on plants in islands. Field surveys were performed 25 times from 2004 to 2010 to investigate the flora in these regions. A total of 793 taxa including 123 families, 421 genera, 695 species, 2 subspeices, 88 varieties, and 8 forms was found. Korean endemic plants including Hepatica insularis and Galium koreanum were 6 taxa. 25 taxa of rare plants including Trachomitum lancifolium, Daphne kiusiana, and Centranthera cochinchinensis var. lutea were confirmed 120 taxa floristic special plant species were confirmed; 11 taxa of the fifth class, four taxa of the fourth class, 28 taxa of the third class. 78 taxa of naturalized plants were confirmed

H-1-MRS of femoral red and yellow bone marrow fat composition and water content in healthy young men and women at 3 T

Objectives There is a discrepancy between studies suggesting that higher bone marrow fat saturation is associated with impaired health, and studies suggesting that erythropoiesis increases red bone marrow (RBM) fat saturation in young healthy individuals. Here, we seeked to elucidate these discrepancies by using long TE magnetic resonance spectroscopy (MRS) to study both yellow bone marrow (YBM) and RBM in the femur of healthy volunteers. Materials and methods Thirty-three young healthy volunteers (17 females), age range 20-31 years, underwent long TE H-1 MRS at 3.0 T of RBM and YBM fat composition in the left femur. The water content of the bone marrow depots was measured using short TE MRS. Results The female participants displayed a lower unsaturation in the sampled RBM volume (RBMV) than the males (P <0.01) without displaying a concomitant difference in YBM (P = 0.42). They also showed a higher water content and broader spectral linewidths in RBM (P = 0.04). The water content in RBM strongly associated with broader spectral linewidths (R = 0.887, P MUCH LESS-THAN 0.01) and inversely with RBMV fat unsaturation (R = - 0.365, P = 0.04). Discussion These results partly support the notion that females display higher rate of erythropoiesis and lower fat unsaturation in RBM.Peer reviewe

PCR for Diagnosis of Male Trichomonas vaginalis Infection with Chronic Prostatitis and Urethritis

The aim of this study was to assess the usefulness of PCR for diagnosis of Trichomonas vaginalis infection among male patients with chronic recurrent prostatitis and urethritis. Between June 2001 and December 2003, a total of 33 patients visited the Department of Urology, Hanyang University Guri Hospital and were examined for T. vaginalis infection by PCR and culture in TYM medium. For the PCR, we used primers based on a repetitive sequence cloned from T. vaginalis (TV-E650). Voided bladder urine (VB1 and VB3) was sampled from 33 men with symptoms of lower urinary tract infection (urethral charge, residual urine sensation, and frequency). Culture failed to detect any T. vaginalis infection whereas PCR identified 7 cases of trichomoniasis (21.2%). Five of the 7 cases had been diagnosed with prostatitis and 2 with urethritis. PCR for the 5 prostatitis cases yielded a positive 330 bp band from bothVB1 and VB3, whereas positive results were only obtained from VB1 for the 2 urethritis patients. We showed that the PCR method could detect T. vaginalis when there was only 1 T. vaginalis cell per PCR mixture. Our results strongly support the usefulness of PCR on urine samples for detecting T. vaginalis in chronic prostatitis and urethritis patients