503 research outputs found
Numerical Sensitivity Tests of Volatile Organic Compounds Emission to PM2.5 Formation during Heat Wave Period in 2018 in Two Southeast Korean Cities
A record-breaking severe heat wave was recorded in southeast Korea from 11 July to 15 August 2018, and the numerical sensitivity simulations of volatile organic compound (VOC) to secondarily generated particulate matter with diameter of less than 2.5 mu m (PM2.5) concentrations were studied in the Busan and Ulsan metropolitan areas in southeast Korea. A weather research and forecasting (WRF) model coupled with chemistry (WRF-Chem) was employed, and we carried out VOC emission sensitivity simulations to investigate variations in PM2.5 concentrations during the heat wave period that occurred from 11 July to 15 August 2018. In our study, when anthropogenic VOC emissions from the Comprehensive Regional Emissions Inventory for Atmospheric Transport Experiment-2015 (CREATE-2015) inventory were increased by approximately a factor of five in southeast Korea, a better agreement with observations of PM2.5 mass concentrations was simulated, implying an underestimation of anthropogenic VOC emissions over southeast Korea. The simulated secondary organic aerosol (SOA) fraction, in particular, showed greater dominance during high temperature periods such as 19-21 July, 2018, with the SOA fractions of 42.3% (in Busan) and 34.3% (in Ulsan) among a sub-total of seven inorganic and organic components. This is considerably higher than observed annual mean organic carbon (OC) fraction (28.4 +/- 4%) among seven components, indicating the enhancement of secondary organic aerosols induced by photochemical reactions during the heat wave period in both metropolitan areas. The PM2.5 to PM10 ratios were 0.69 and 0.74, on average, during the study period in the two cities. These were also significantly higher than the typical range in those cities, which was 0.5-0.6 in 2018. Our simulations implied that extremely high temperatures with no precipitation are significantly important to the secondary generation of PM2.5 with higher secondary organic aerosol fraction via photochemical reactions in southeastern Korean cities. Other possible relationships between anthropogenic VOC emissions and temperature during the heat wave episode are also discussed in this study
Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma: Prevalence and Causative Factors of Extrahepatic Collateral Arteries in 479 Patients
OBJECTIVE: We wanted to investigate the prevalence and causative factors of extrahepatic arterial blood supply to hepatocellular carcinoma (HCC) at its initial presentation and during chemoembolization. MATERIALS AND METHODS: Between February 1998 and April 2000, consecutive 479 patients with newly diagnosed HCC were prospectively enrolled into this study. A total of 1629 sessions of transcatheter arterial chemoembolization (TACE) were performed in these patients (range: 1-15 sessions; mean: 3.4 sessions) until April 2004. For each TACE procedure, we determined the potential extrahepatic collateral arteries (ExCAs) depending on the location of the tumor, and we performed selective angiography of all suspected collaterals that could supply the tumor. The prevalence of ExCAs and the causative factors were analyzed. RESULTS: At initial presentation, 82 (17%) of these 479 patients showed 108 ExCAs supplying tumors. Univariate analysis showed that tumor size (p or =5 cm) was significantly higher than that for those patients with a small tumor (< 5 cm) (p < 0.01). CONCLUSION: The presence of ExCAs supplying HCC is rather common, and the tumor size is a significant causative factor for the development of these collateral arteries.This study was supported by a grant
(0620220-1) from the National R & D
Program for Cancer Control, Ministry of
Health & Welfare, Republic of Korea
Angiolipoma of the Posterior Mediastinum with Extension into the Spinal Canal: A Case Report
Angiolipoma is a rare benign soft tissue tumor, an unusual variant of lipoma, consisting of fatty and vascular components and located in the subcutis, usually in the trunk and extremities. We report a case of posterior mediastinal angiolipoma extending into the spinal canal and showing both fat and angiomatous features on CT scan
Manumycin from a new Streptomyces strain shows antagonistic effect against methicillin-resistant Staphylococcus aureus (MRSA)/vancomycin-resistant enterococci (VRE) strains from Korean Hospitals
An antimicrobial compound, highly effective against multidrug-resistant (MDR) bacteria, purified from a Streptomyces strain was identified as manumycin. The minimal inhibitory concentrations (MICs) of manumycin against 8 different strains of methicillin-resistant Staphylococcus aureus (MRSA) were ranged 2 to 32 μg/ml. Similarly, MICs of manumycin against 4 vancomycin-resistant enterococci (VRE) strains were ranged 8 to 32 μg/ml while it remained ineffective against 4 other VRE strains. Compared to vancomycin, manumycin provided slightly weaker activity against MRSA strains but stronger activity against 4 VRE strains. This is the first report of antagonistic effect of manumycin against MDR pathogens.Keywords: Manumycin, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE)African Journal of Biotechnology Vol. 12(17), pp. 2249-225
Severe bradycardia during suspension laryngoscopy performed after tracheal intubation using a direct laryngoscope with a curved blade -A case report-
There are a few reports about bradycardia or asystole caused by direct laryngoscopy. However, we encountered severe bradycardia in response to suspension laryngoscopy for laryngeal polypectomy after safely completing tracheal intubation using a direct laryngoscope with a curved blade. The tip of the curved blade of the direct laryngoscope is positioned at the vallecula (between the base of the tongue and the pharyngeal surface of the epiglottis) during tracheal intubation, while the blade tip of the suspension laryngoscope lifts the laryngeal surface of the epiglottis or supraglottic area during surgery. Therefore, suspension laryngoscopy can be said more vagotonic than curved-blade direct laryngoscopy. Because of the possibility of bradycardia induced by suspension laryngoscopy, clinicians must be careful about severe bradycardia even after safely completing intubation using direct laryngoscopy
Follow-up CT Evaluation of the Mural Changes in Active Takayasu Arterities
OBJECTIVE: We wanted to evaluate the mural changes by CT on the follow-up examination of patients with active Takayasu arteritis. MATERIALS AND METHODS: The study included 18 patients, (4 males and 14 females), with active Takayasu arteritis. A total of 44 CT examinations were done during the follow-up period (mean: 55.6 months). At the time of the last follow-up CT, the disease, on the basis of the erythrocyte sedimentation rate (ESR), was found to be inactive in five patients and the disease was active and persistent in 13 patients. The thickness and CT attenuation of the aortic wall on the precontrast, arterial and venous phases were measured on the initial and the follow-up CT examinations. The ratio of the mural attenuation over that of the back muscle on the initial CT was compared with the ratio found on the follow-up CT. RESULTS: The initial CT findings included high density and calcifications of the aortic wall in the precontrast images and a thickened wall with enhancements in the arterial and the venous phases. A low-attenuation ring was demonstrated in the venous phase in 15 patients (83%). On the follow-up evaluation, the mean mural thickness decreased significantly from 4.1 mm to 2.4 mm. The mean mural attenuation ratio in the venous phase decreased significantly from 1.9 to 1.3 (p = 0.001). The low attenuation ring was identified in seven patients (39%) who had only with active, persistent Takayasu arteritis. CONCLUSION: The mural changes demonstrated by the follow-up CT evaluations for the patients with active Takayasu arteritis included a decrease of the mural thickness and enhancement, disappearance of the low-attenuation ring on the venous phase, and an increase of the mural attenuation and calcification on the precontrast phase
Shaping the tip of microcatheters for superselective catheterization: steam vs. manual methods
PURPOSEWe aimed to evaluate and compare the shapeability and stability of five microcatheters commonly used in interventional radiology after steam shaping and manual shaping.METHODSSteam shaping was performed using three mandrels of different angles: L(S) shape (90°), U(S) shape (180°), and O(S) shape (360°). Three manual shapes—L(M), U(M), and O(M)—were made to have a similar angle to their steam-shaped counterparts. The stability of the microcatheters was evaluated by passing them through a 5 F catheter and inserting microguidewires. The tip angles of the microcatheters and the angle change rates were compared between groups.RESULTSThe mean angle of the microcatheters after steam shaping was 42.4°–54.1° for L(S) shape, 80.2°–96.7° for U(S) shape, and 130.7°–150.8° for O(S) shape. Five microcatheters showed significantly different mean angle reductions after passing through the 5 F catheter (17.4%–30.3%) and inserting microguidewires (24.1%–61.2%). Different microguidewires also caused significantly different mean angle reductions (34.6%–50.8%). The reduced angle caused by the guidewire was almost completely recovered after withdrawing it (93.2%–101.6%). Although manual-shaped microcatheters showed a 4.2%–6.3% greater angle reduction than steam-shaped microcatheters after passing through the 5 F catheter, the final tip angle was not significantly different between the two groups and was within 10%.CONCLUSIONThe tip angle of the microcatheters after steam shaping using mandrels may differ depending on the shape of the mandrel and the type of microcatheter used, and the stability varies depending on the type of microcatheter. The manual shaping of microcatheters can be a good alternative to steam shaping
Safety and Efficacy of Second-Generation Everolimus-Eluting Xience V Stents Versus Zotarolimus-Eluting Resolute Stents in Real-World Practice Patient-Related and Stent-Related Outcomes From the Multicenter Prospective EXCELLENT and RESOLUTE-Korea Registries
ObjectivesThis study sought to compare the safety and efficacy of the Xience V/Promus everolimus-eluting stent (EES) (Abbott Vascular, Temecula, California) with the Endeavor Resolute zotarolimus-eluting stent (ZES-R) (Medtronic Cardiovascular, Santa Rosa, California) in “all-comer” cohorts.BackgroundOnly 2 randomized controlled trials have compared these stents.MethodsThe EXCELLENT (Efficacy of Xience/Promus Versus Cypher to Reduce Late Loss After Stenting) and RESOLUTE-Korea registries prospectively enrolled 3,056 patients treated with the EES and 1,998 patients treated with the ZES-R, respectively, without exclusions. Stent-related composite outcomes (target lesion failure [TLF]) and patient-related composite outcomes were compared in crude and propensity score-matched analyses.ResultsOf 5,054 patients, 3,830 (75.8%) had off-label indication (2,217 treated with EES and 1,613 treated with ZES-R). The stent-related outcome (82 [2.7%] vs. 58 [2.9%], p = 0.662) and the patient-related outcome (225 [7.4%] vs. 153 [7.7%], p = 0.702) did not differ between EES and ZES-R, respectively, at 1 year, which was corroborated by similar results from the propensity score-matched cohort. The rate of definite or probable stent thrombosis (18 [0.6%] vs. 7 [0.4%], p = 0.306) also was similar. In multivariate analysis, off-label indication was the strongest predictor of TLF (adjusted hazard ratio: 2.882; 95% confidence interval: 1.226 to 6.779; p = 0.015).ConclusionsIn this robust real-world registry with unrestricted use of EES and ZES-R, both stents showed comparable safety and efficacy at 1-year follow-up. Overall incidences of TLF and definite stent thrombosis were low, even in the patients with off-label indication, suggesting excellent safety and efficacy of both types of second-generation drug-eluting stents
Bronchial and non-bronchial systemic artery embolization with transradial access in patients with hemoptysis
PURPOSEWe aimed to determine the safety and feasibility of transradial access (TRA) in bronchial artery and non-bronchial systemic artery (NBSA) embolization in patients with non-massive hemoptysis.METHODSThis retrospective study was approved by the Institutional Review Board. Among the 300 patients treated for hemoptysis with bronchial artery and NBSA embolization between April 2018 and July 2019, 19 procedures in 19 patients were conducted by TRA and were retrospectively analyzed. TRA was considered when the bronchial artery or NBSA originated from the arch vessel or its tributaries. The exclusion criteria of TRA included Barbeau C or D waveform and a radial artery diameter of less than 1.8 mm on ultrasound. TRA was also avoided in cases of the high-origin bronchial artery (i.e., T4 or higher level of the aorta). The hemoptysis-free time was estimated using the Kaplan–Meier method.RESULTSThe technical success (i.e., embolization of all target artery with TRA) rate was 94.7% (18 out of 19 patients). In terms of the target arteries, embolization with TRA was technically successful in treating 47 out of 48 arteries (97.9%). The 1-month and 6-month hemoptysis-free rates were 89.5% (17/19) and 73.7% (14/19), respectively. The only adverse event was iatrogenic dissection of the bronchial artery with little clinical significance in 1 patient. No access site complications were identified on post-procedure day 1 ultrasonography.CONCLUSIONWith proper patient selection, TRA offers a safe and effective approach to embolize the bronchial arteries and NBSAs in patients with hemoptysis
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