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To compare postoperative pain, nausea and vomiting, and bleeding between intravascular dexamethasone injection group and control group among children undergoing powered intracapsular tonsillectomy and adenoidectomy (PITA).Retrospective review of medical records was performed for pediatric patients who underwent PITA from March 1, 2017, to February 28, 2021, at a tertiary referral medical center in South Korea. Postoperative pain and nausea were measured using the visual analogue scale (VAS) from the postoperative day (POD) 0 to POD 6. The number of analgesics administered and the number of vomiting episodes were recorded in the same period. The repeatedly measured parameters were statistically analyzed between the dexamethasone group and control group.A total of 71 children with complete questionnaires including 44 boys and 27 girls were included, and the mean age was 7.49 ± 2.44 years. There were 33 patients in the dexamethasone group and 38 in the control group. Postoperative pain (p = 0.169) or nausea (p = 0.460) on the VAS showed no statistically significant difference between the two groups. Postoperative analgesics showed no difference between the groups (p = 0.398), and neither did postoperative vomiting (p = 0.270). In both groups, no child showed signs of postoperative bleeding.This study indicates that the beneficial effects of intravascular dexamethasone administration in PITA may not be evident. This might be due to the superior outcome of the PITA technique compared to total extracapsular tonsillectomy. Therefore, otolaryngologists performing PITA may not necessarily need to administer dexamethasone in children before surgery.

Background: Olfactory and gustatory dysfunction have been reported as characteristic symptoms of coronavirus disease 2019 (COVID-19). This study evaluated olfactory and gustatory dysfunction in mild COVID-19 patients using validated assessment methods. Methods: A prospective surveillance study was conducted for mild COVID-19 patients who were isolated at the Gyeonggi International Living and Treatment Support Center (LTSC), Korea. Olfactory function was assessed using the Korean version of the Questionnaire of Olfactory Disorders (QOD) and Cross-Cultural Smell Identification Test (CC-SIT). Gustatory function was assessed using an 11-point Likert scale and 6-n-propylthiouracil, phenylthiocarbamide, and control strips. All patients underwent nasal and oral cavity endoscopic examination. Findings: Of the 62 patients at the LTSC, 15 patients (24.2%) complained of olfactory or gustatory deterioration on admission. Four of 10 patients who underwent functional evaluation did not have general symptoms and 2 patients were asymptomatic. The mean sQOD-NS and QOD-VAS scores were 13 ± 6 and 4.7 ± 3.6, respectively. The mean CC-SIT score was 8 ± 2. No patients showed anatomical abnormalities associated with olfactory dysfunction on endoscopic examination. The mean Likert scale score for function was 8 ± 2, and there were no abnormal lesions in the oral cavity of any patient. Interpretation: The prevalence of olfactory and gustatory dysfunction was 24.2% in mild COVID-19 patients. All patients had hyposmia due to sensorineural olfactory deterioration, which was confirmed using validated olfactory and gustatory evaluation methods and endoscopic examination. Olfactory and gustatory dysfunction may be characteristic indicators of mild COVID-19. Funding Statement: No funding. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: This study protocol was approved by the Institutional Review Board of the Korea University Ansan Hospital (2020AS0122).

The growth rate of biomass and removal characteristics of nitrogen and phosphorus were examined using nitrate and ammonia as nitrogen sources for batch cultures of the heterotrophic microalgae, Chlorella sorokiniana. The initial nitrogen concentrations examined were 10, 20, 40, 80 and 160 mg-N l−1. The results show that a nitrate concentration of 80 mg-N l−1 as a nitrogen source provided the maximum growth rate and greatest removal of nitrogen and phosphorus, while the growth rate decreased with decreasing ammonia concentration. The maximum growth rate and removal amounts of nitrate and phosphorus were 0.48 d−1, 32.6 mg-N and 5.9 mg-P, respectively, with 80 mg NO3–N l−1. With ammonia as a nitrogen source, the maximum growth rate and removal amounts of nitrogen and phosphorus were 0.6 d−1, 79.2 mg-N and 5.9 mg-P, respectively, with 160 mg NH3–N l−1. When ammonia was used as a nitrogen source, removal rates of nitrogen and phosphorus were higher than those with nitrate. However, the pH decrease caused by ammonia affected the growth of Chlorella sorokiniana, resulting in a lower yield of biomass than when using nitrate as a nitrogen source.

In wastewater treatment using microalgae, the effects of wavelength and wavelength mixing ratio on microalgae growth and removal of nitrogen and phosphorus were evaluated using LEDs (white light, 670 nm, 450 nm, and 525 nm). Microalgae production rates were enhanced by a maximum of 45% with 400–700 nm white light compared to that of a single wavelength. The phosphorus removal rate was as high as 90% with blue light. When red light and blue light were mixed and supplied, the microalgae production rate was about 50% higher than the rate of the culture with white light. Nitrogen and phosphorus removal rates were as high as approximately 15 mg/L/day at a wavelength mixing ratio of 7 (red light):3 (blue light) and 2.1 mg/L/day at a wavelength mixing ratio of 5 (red light):5 (blue light).

Batch experiments were conducted to investigate the effects of Na(+) concentration on hydrogen production with dark fermentation. The Na(+) concentration was varied from 0 to 8 g/L in the mixed culture using an anaerobic sludge treated by acid. The maximum hydrogen production was achieved with 1 g-Na(+)/L, whereas the hydrogen production was decreased over 2 g-Na(+)/L due to the inhibitory of Na(+). The mechanisms of Na(+) inhibition to the hydrogen production are studied using pure culture of Clostridium butyricum by calculating the energy balance. At a high sodium concentration, C. butyricum used a greater proportion of the ATP generated via fermentation for cell maintenance rather than for cell synthesis. Additionally, higher Na(+) concentrations shifted the fermentation process toward the acetate synthesis pathway instead of the butyrate pathway, and the value of Y(X/ATP) decreased. With high Na(+) concentrations, a greater ratio of hydrogen was produced via the oxidation of NADH. Excess hydrogen production decreased as the Na(+) concentration increased.

This study evaluated that the effects of concentration of VFAs (volatile fatty acids), such as acetate and butyrate, on bio-hydrogen production from high salinity organic substrate with halophilic hydrogenproducing bacteria of Clostridium bifermentans 3AT-ma. Glucose medium was used a substrate. Supplementary acetate and butyrate concentrations were ranged 0 to 500 mM and 0 to 250 mM, respectively. The increased concentration of acetate and butyrate significantly influenced to hydrogen production. At the initial condition, VFAs concentration of 0 g/L, maximum hydrogen was produced. The hydrogen production was decreased as increasing dosage of acetate and butyrate. The inhibitory effect by adding acetate on fermentative hydrogen production was less significant compared to that by butyrate. A modified Gompertz equation could be successfully described the cumulative H2 production at different VFAs concentrations. In addition, the inhibition by adding VFAs on hydrogen production was described well by a non-competitive inhibition model.

Many countries have investigated the new sandfilter backwash water treatment process to recycling the backwash water. There are various methods for reclamation of sandfilter backwash water (Such as Sedimentation, Sand filter, Membrane Filtration System ETC…), but the membrane filtration system is generally regarded as most efficient. This study is applied tubular membrane filtration system for backwash water treatment. In general, crossflow filtration operation mode is used in the tubular membrane system. Thus, the objective of this study is to verify the application of a dead-end filtration operation mode for tubular membrane filtration system in order to reduce electricity usage for the pump. For efficient operation of filtration and bleed, a matrix was established to simulate various sets of filtration and bleed times. Based on the results on the applicability of the matrix, it was possible to mathematically estimate the concentrated final suspended solids concentration. Deciding values for operational parameters such as filtration time that depend on the permeate flux and suspended solids concentration of inlet feed water was deemed appropriate. Dead-end filtration operation experimental results indicated that flow occlusion did not occur and operations could be safely performed using this process.

Various adsorptive materials, including granular activated carbon (GAC) and ground tire rubber (GTR), were mixed with compost in biofilters used for treating gaseous toluene, and the effects of the mixtures on the stability of biofilter performance were investigated. A transient loading test demonstrated that a sudden increase in inlet toluene loading was effectively attenuated in the compost/GAC biofilter, which was the most significant advantage of adding adsorptive materials to the biofilter packing media. Under steady conditions with inlet toluene loading rates of 18.8 and 37.5 g/m3/h, both the compost and the compost/GAC biofilters achieved overall toluene removal efficiencies greater than 99%. In the compost/GAC mixture, however, biodegradation activity declined as the GAC mass fraction increased. Because of the low water-holding capacity of GTR, the compost/ground tire mixture did not show a significant improvement in toluene removal efficiency throughout the entire operational period. Furthermore, nitrogen limitations affected system performance in all the biofilters, but an external nitrogen supply resulted in the recovery of the toluene removal efficiency only in the compost biofilter during the test periods. Consequently, the introduction of excessive adsorptive materials was unfavorable for long-term performance, suggesting that the mass ratio of the adsorptive materials in such mixtures should be carefully selected to achieve high and steady biofilter performance.

A new on-line predictive monitoring and prediction model for periodic biological processes is proposed using the multiway non-Gaussian modeling. The basic idea of this approach is to use multiway non-Gaussian modeling to extract some dominant key components from daily normal operation data in a periodic process, and subsequently combining these components with predictive statistical process monitoring techniques. The proposed predictive monitoring method has been applied to fault detection and diagnosis in the biological wastewater-treatment process, which is based on strong diurnal characteristics. The results show the power and advantages of the proposed predictive monitoring of a continuous process using the multiway predictive monitoring concept, which is thus able to give very useful conceptual results for a daily monitoring process and also enables a more rapid detection of the process fault than other traditional monitoring methods.

The concentrations of three different size fractions of particulate matter (PM) including PM2.5, PM10, and TSP were determined continuously at hourly intervals from four different sites in Seoul, Korea during the spring of 2001. To learn the effects of wind speed change on PM fractionation, the entire data sets were initially sorted into three particle fractions such as: fine (F: PM2.5), coarse (C: PM10-PM2.5), and giant (G: TSP-PM10). The inter-fraction relationships of PM were then explored by linear regression analysis of the data divided into four wind speed regimes. The results of this analysis, when examined in terms of either relative dominance between different PM fractions (i.e., in terms of their slope values) or strength of correlations, indicate the existence of diverse inter-fraction patterns. Most importantly, the physical influence of wind speed is seen to be reflected most efficiently between fine and coarse particle fractions, as the relative contribution of coarse fraction to the mass concentration of total particles (e.g., PM10) changes proportionally with changes in wind speed. However, such systematic patterns decrease noticeably between fine and giant fractions, as they can be affected more sensitively by such factors as the nature of their sources or the surrounding environmental conditions. The results of our comparative analysis thus confirm that wind speed is a useful barometer to distinguish and predict the behavior of different particle fractions in relation to each other.

Rib tumors are uncommon, constituting only 5% to 10% of all bony neoplasms. Cholesterol granuloma is also rare and is described as inflammatory granulation that occurs in response to the deposition of cholesterol crystals. Cholesterol granulomas are found most commonly in the paranasal sinuses or temporal bones, but there are also rare reports of their occurrence in the peritoneum, parotid gland, lymph nodes, thyroglossal duct, kidney, liver, and spleen. Involvement of the ribs has rarely been described previously. We report a rare case of cholesterol granuloma involving the second rib of a 38-year-old-woman who presented with a slowly growing lesion of the anterior aspect of the chest.

In the present study, TSP-bound metal concentrations were measured from seven different urbanized locations in Seoul, Korea for the period from March 2001 through May 2002. Our measurement data were analyzed to explore the possible influences of spatial and temporal factors on metal distribution characteristics. To determine the importance of those aspects, the measured concentrations were compared between different metals and between different sites in terms of several criteria: (1) absolute concentrations and enrichment factor (EF) values; (2) coefficient of variation (CV) values of metal concentrations; (3) relative patterns of temporal variations; and (4) relative abundance of strong correlations. According to our analysis of metal distribution characteristics in the study area, the main results of our study can be summarized as follows: (1) a number of metals (e.g., Cd, Cu, and Pb) are highly enriched relative to the average crustal ratios (to Fe); (2) the behavior of Cu is found to vary irregularly, while Fe, Mn, and Pb are tightly coupled both spatially and temporally in the study area; (3) for most elements except Cu and Cd, seasonal variations are observed in a systematic manner; and (4) when compared against those observed in other parts of the world, our Cu and Cd concentrations observed in many locations of Seoul are notably high. The overall results of our study suggest that the distribution characteristics of metals can be regulated strongly by spatial and temporal factors and that such controls are distinguished very clearly between different metal types.

The purposes of this study were to evaluate the potential production of nitrous oxide (N2O), which is known as a greenhouse gas, to identify the reaction responsible for it and to examine the effects of oxygen and moisture content on nitrification, denitrification and N2O production. Applying a tracer method using a 15N-isotope into an oxygen controllable reactor with artificial refuse proved that biological denitrification was a main source of released N2O even when the oxygen of the bulk atmosphere was as high as 15%. Calculating the mass balance for nitrogenous compounds showed that only denitrification occurred as the sole microbial process when the bulk oxygen was 0–5%. With increasing oxygen above 5% nitrification also began to occur simultaneously with denitrification. As the bulk space of the refuse became aerobic, the total amount of N2 produced from denitrification decreased but the proportion of N2O in the (N2 + N2O) increased. Denitrification was the main source of released N2O when the moisture content was between 40–60% and oxygen 10%. The amounts of nitrification, denitrification and N2 production increased as the moisture content increased.