151 research outputs found
The Development of Recurrent Choroidal Neovascularization in a Patient with Choroidal Coloboma
We report a case of recurrent choroidal neovascularization (CNV) in an eye with chorioretinal coloboma. A 36-year-old woman presented complaining of decreased visual acuity (VA) in her left eye. Best corrected visual acuity (BCVA) was 20/200 and iris coloboma was observed. Funduscopy and fluorescein angiography (FA) showed CNV in the superior extrafoveal region with chorioretinal coloboma reaching just inferior to the optic disc. No other cause for CNV was observed except for the chorioretinal coloboma. BCVA improved to 20/30 after laser photocoagulation. She revisited our clinic for deteriorating VA (20/400) in the same eye 3 years after treatment. Funduscopy and FA demonstrated recurrent CNV with subfoveal hemorrhage. Photodynamic therapy (PDT) was followed by three consecutive intravitreal bevacizumab injections (IVB) for the subfoveally-located CNV. However, the CNV persisted with the appearance of a fresh subretinal hemorrhage. Additional PDT was combined with IVB on the same day 6 months after the initial PDT. The CNV regressed 3 months after treatment and has not recurred as of 8 months after the last treatment. The patient's BCVA improved to 20/60. This case suggests that PDT combined with IVB can be an alternative treatment for the management of recurrent CNV after laser photocoagulation in eyes with chorioretinal coloboma
Evaluation for Damaged Degree of Vegetation by Forest Fire Using LiDAR and Digital Aerial Photograph
The amount of vegetation physically damaged by forest fire can be evaluated using lidar (Light Detection And Ranging) data because the loss of canopy height and width by forest fire can be relevant to the number of points transmitted to the ground through the canopy of the damaged forest. On the other hand, the biological damage of vegetation caused by forest fire can be obtained from the Normalized Difference Vegetation Index (NDVI), which determines the vegetation vitality. In this study, the degree of physical damage from the lidar data was classified into serious physical damage (SPD) and light physical damage (LPD). The degree of biological damage using NDVI was likewise classified into serious biological damage (SBD) and light biological damage (LBD). Finally, the damaged area was graded into four categories: (a) SPD and SBD, (b) LPD and SBD, (c) SPD and LBD, and (d) LPD and LBD. The accuracy assessment for the area classified into four grades showed an overall accuracy of 0.74, and a kappa value of 0.61 which provides improvement over previous works
Application of the Savitzky-Golay Filter to Land Cover Classification Using Temporal MODIS Vegetation Indices
In this study, the Savitzky-Golay filter was applied to smooth observed unnatural variations in the temporal profiles of the Normalized Difference Vegetation Index (NDVI} and the Enhanced Vegetation Index {EVI} time series from the MODerate Resolution Imaging Spectroradiometer (MODIS}. We computed two sets of land cover classifications based 011 the NDVI and EVI time series before and after applying the Savitzky-Golay filter. The resulting classification from the filtered versions of the vegetation indices showed a substantial improvement in accuracy when compared to the classifications from the unfiltered versions. The classification by the EVIsg had the highest K (0.72} for all classes compared to those of the EVI (0.67}, NDVI (0.63}, and NDV/sg (0.62). Therefore, we conclude that the EVIsg is best suited for land cover classification compared to the other data sets in this study
Vascular effects of estrogen in type II diabetic postmenopausal women
AbstractOBJECTIVESWe assessed the effects of estrogen on vascular dilatory and other homeostatic functions potentially affected by nitric oxide (NO)-potentiating properties in type II diabetic postmenopausal women.BACKGROUNDThere is a higher cardiovascular risk in diabetic women than in nondiabetic women. This would suggest that women with diabetes do not have the cardioprotection associated with estrogen.METHODSWe administered placebo or conjugated equine estrogen, 0.625 mg/day for 8 weeks, to 20 type II diabetic postmenopausal women in a randomized, double-blinded, placebo-controlled, cross-over design.RESULTSCompared with placebo, estrogen tended to lower low-density lipoprotein (LDL) cholesterol levels by 15 ± 23% (p = 0.007) and increase high-density lipoprotein (HDL) cholesterol levels by 8 ± 16% (p = 0.034). Thus, the ratio of LDL to HDL cholesterol levels significantly decreased with estrogen, by 20 ± 24%, as compared with placebo (p = 0.001). Compared with placebo, estrogen tended to increase triglyceride levels by 16 ± 48% and lower glycosylated hemoglobin levels by 3 ± 13% (p = 0.295 and p = 0.199, respectively). However, estrogen did not significantly improve the percent flow-mediated dilatory response to hyperemia (17 ± 75% vs. placebo; p = 0.501). The statistical power to accept our observation was 81.5%. Compared with placebo, estrogen did not significantly change E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein-1 or matrix metalloproteinase-9 levels. Compared with placebo, estrogen tended to decrease tissue factor antigen and increase tissue factor activity levels by 7 ± 46% and 5 ± 34%, respectively (p = 0.321 and p = 0.117, respectively) and lower plasminogen activator inhibitor-1 levels by 16 ± 31% (p = 0.043).CONCLUSIONSThe effects of estrogen on endothelial, vascular dilatory and other homeostatic functions were less apparent in type II diabetic postmenopausal women, despite the beneficial effects of estrogen on lipoprotein levels
C-Band GaN Dual-Feedback Low-Noise Amplifier MMIC with High-Input Power Robustness
In this paper, using the 0.2 μm ETRI GaN HEMT process, we developed a C-band GaN dual-feedback low-noise amplifier MMIC for an RF receiver module that requires high-input power robustness. By applying a feedback microstrip line at the source of the transistor and series resistor-capacitor (RC) feedback between the gate and the drain of the transistor, we obtained stable amplifier operation and a compromised impedance trace for both input impedance matching and noise matching while suppressing performance degradation of the maximum available gain and minimum noise figure. The developed low-noise amplifier MMIC, which implements simple matching circuits by using biasing elements as matching elements, had a linear gain of more than 21.4 dB and a noise figure of less than 1.91 dB in the wide bandwidth of 4.3–7.4 GHz. Under the single-tone power test, the low-noise amplifier MMIC had an output P1dB of 14.3–20.1 dBm, and the two-tone intermodulation distortion measurement exhibited an input third-order intercept point (IIP3) of 2.2–5.6 dBm in the same frequency range as the above
Characteristics of Classified Aerosol Types in South Korea during the MAPS-Seoul Campaign
During the Megacity Air Pollution Studies-Seoul (MAPS-Seoul) campaign from May to June 2015, aerosol optical properties in Korea were obtained based on the AERONET sunphotometer measurement at five sites (Anmyon, Gangneung_WNU, Gosan_SNU, Hankuk_UFS, and Yonsei_University). Using this dataset, we examine regional aerosol types by applying a number of known aerosol classification methods. We thoroughly utilize five different methods to categorize the regional aerosol types and evaluate the results from each method by inter-comparison. The differences and similarities among the results are also discussed, contingent upon the usage of AERONET inversion products, such as the single scattering albedo. Despite several small differences, all five methods suggest the same general features in terms of the regionally dominant aerosol type: Fine-mode aerosols with highly absorbing radiative properties dominate at HankukUFS and Yonsei_University; non-absorbing fine-mode particles form a large portion of the aerosol at Gosan_SNU; and coarse-mode particles cause some effects at Anmyon. The analysis of 3-day back-trajectories is also performed to determine the relationship between classified types at each site and the regional transport pattern. In particular, the spatiotemporally short-scale transport appears to have a large influence on the local aerosol properties. As a result, we find that the domestic emission in Korea significantly contributes to the high dominance of radiation-absorbing aerosols in the Seoul metropolitan area and the air-mass transport from China largely affects the western coastal sites, such as Anmyon and Gosan_SNU
Regional Characteristics of NO2 Column Densities from Pandora Observations during the MAPS-Seoul Campaign
Vertical column density (VCD) of nitrogen dioxide (NO2) was measured using Pandora spectrometers at six sites on the Korean Peninsula during the Megacity Air Pollution Studies-Seoul (MAPS-Seoul) campaign from May to June 2015. To estimate the tropospheric NO2 VCD, the stratospheric NO2 VCD from the Ozone Monitoring Instrument (OMI) was subtracted from the total NO2 VCD from Pandora. European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis wind data was used to analyze variations in tropospheric NO2 VCD caused by wind patterns at each site. The Yonsei/SEO site was found to have the largest tropospheric NO2 VCD (1.49 DU on average) from a statistical analysis of hourly tropospheric NO2 VCD measurements. At rural sites, remarkably low NO2 VCDs were observed. However, a wind field analysis showed that trans-boundary transport and emissions from domestic sources lead to an increase in tropospheric NO2 VCD at NIER/BYI and KMA/AMY, respectively. At urban sites, high NO2 VCD values were observed under conditions of low wind speed, which were influenced by local urban emissions. Tropospheric NO2 VCD at HUFS/Yongin increases under conditions of significant transport from urban area of Seoul according to a correlation analysis that considers the transport time lag. Significant diurnal variations were found at urban sites during the MAPS-Seoul campaign, but not at rural sites, indicating that it is associated with diurnal patterns of NO2 emissions from dense traffic
Long-Pulsed Nd:YAG Laser Treatment of Warts: Report on a Series of 369 Cases
Various treatment methods have been adopted in the management of warts; however, there is still no consensus on first-line treatment. This study was designed to evaluate the efficacy of long-pulsed Nd:YAG laser in the treatment of warts. Over the course of 1 yr, 369 patients with recalcitrant or untreated warts were exposed to a long-pulsed Nd:YAG laser. The following parameters were used: spot size, 5 mm; pulse duration, 20 msec; and fluence, 200 J/cm2. No concomitant topical treatment was used. In all, 21 patients were lost during follow up; hence, the data for 348 patients were evaluated. The clearance rate was 96% (336 of the 348 treated warts were eradicated). The clearance rate of verruca vulgaris after the first treatment was very high (72.6%), whereas the clearance rate of deep palmopantar warts after the first treatment was low (44.1%). During a median follow-up period of 2.24 months (range, 2-10 months), 11 relapses were seen (recurrence rate, 3.27%). In conclusion, long-pulsed Nd:YAG laser is safe and effective for the removal or reduction of warts and is less dependent on patient compliance than are other treatment options
Prognostic significance of interim PET/CT based on visual, SUV-based, and MTV-based assessment in the treatment of peripheral T-cell lymphoma
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