Efficacy of a Mouthwash Containing CHX and CPC in SARS-CoV-2–Positive Patients: A Randomized Controlled Clinical Trial

Soon after the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, preprocedural mouthwashes were recommended for temporarily reducing intraoral viral load and infectivity of individuals potentially infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in order to protect medical personnel. Particularly, the antiseptic cetylpyridinium chloride (CPC) has shown virucidal effects against SARS-CoV-2 in vitro. Therefore, the aim of this randomized controlled clinical trial was to investigate the efficacy of a commercially available mouthwash containing CPC and chlorhexidine digluconate (CHX) at 0.05% each in SARS-CoV-2–positive patients as compared to a placebo mouthwash. Sixty-one patients who tested positive for SARS-CoV-2 with onset of symptoms within the last 72 h were included in this study. Oropharyngeal specimens were taken at baseline, whereupon patients had to gargle mouth and throat with 20 mL test or placebo (0.9% NaCl) mouthwash for 60 s. After 30 min, further oropharyngeal specimens were collected. Viral load was analyzed by quantitative reverse transcriptase polymerase chain reaction, and infectivity of oropharyngeal specimens was analyzed by virus rescue in cell culture and quantified via determination of tissue culture infectious doses 50% (TCID50). Data were analyzed nonparametrically (α = 0.05). Viral load slightly but significantly decreased upon gargling in the test group (P = 0.0435) but not in the placebo group. Viral infectivity as measured by TCID50 also significantly decreased in the test group (P = 0.0313), whereas there was no significant effect but a trend in the placebo group. Furthermore, it was found that the specimens from patients with a vaccine booster exhibited significantly lower infectivity at baseline as compared to those without vaccine booster (P = 0.0231). This study indicates that a preprocedural mouthwash containing CPC and CHX could slightly but significantly reduce the viral load and infectivity in SARS-CoV-2–positive patients. Further studies are needed to corroborate these results and investigate whether the observed reductions in viral load and infectivity could translate into clinically useful effects in reducing COVID-19 transmission (German Clinical Trials Register DRKS00027812)

Diagnosis of functionality and use of a recreational park with the aplocation of the placemaking method

Artykuł opisuje wyniki badań sposobów użytkowania jednego z warszawskich parków rekreacyjnych. Podejmuje także tematy funkcjonowania poszczególnych przestrzeni i w ograniczonym zakresie ocenę jakości wizualnej krajobrazu tego obiektu. Diagnoza terenu jest próbą wykorzystania metody placemaking, która do tej pory używana była w analizach miejskich przestrzeni publicznych, na potrzeby oceny podmiejskiego kompleksu leśno-rekreacyjnego. Wyniki strukturyzowanych obserwacji uporządkowane zostały za pomocą metody SWOT, która zestawia obecne mocne i słabe strony funkcjonalnego aspektu parku oraz wskazuje na możliwe scenariusze (szanse i zagrożenia) w przyszłości.The article describes the results of studies on the usage of a recreational park in Warsaw and the functioning of individual spaces, as well as the limited assessment of the visual quality of the landscape of this facility. The diagnosis of the area is an attempt in adapting the placemaking method, which has so far been used in the analysis of urban public spaces for the purposes of assessing a suburban forest-recreational complex. The results of structured observations were organized with the use of SWOT method, which summarizes the current strengths and weaknesses of the functional aspect of the park and points to possible scenarios (opportunities and threats) in the future

A review on ash formation during pulverized fuel combustion: State of art and future research needs

Solid hydrocarbon fuels-coal and biomass are commonly used for large-scale heat and power generation worldwide. The solid incombustible ash, residing from combustion, leads to several operational issues. Ash-related problems such as slagging, fouling, corrosion, erosion (all resulting in boiler efficiency reduction), emissions of particulate matter and reuse or disposal of captured ashes, may restrict future use of the said fuels. The above mentioned technical bottlenecks are closely related with fuel and combustion process characteristics, as during the combustion process, solid fuel particle undergoes several physical and chemical transformations, which all depend on both the fuel ash chemistry as well as combustion technology. The said transformations include volatilization, fragmentation, chemical reactions, nucleation, coagulation, homogeneous/heterogeneous condensation, All of these processes play a role in the formation of submicron through coarse-sized ash particles are generated. The present paper provides a synthesis of available information on typical fuel characteristics and operating parameters responsible for the said transformations and final size distribution of the ash particles based on critically reported investigations and modeling efforts to date. The fuel characteristics addressed in the review are fuel mineral matter composition and its association (mineralogy), particles' size, shape and density, as well as char structure etc. Also reviewed is the interrelation between the fuel characteristics with operating parameters essential for the understanding of ash transformations. Descriptions of a variety of analytical methods applied to quantify the parameters responsible for ash formation are also covered, including the recognition of modeling efforts to date (from the simple calculations to advance numerical simulations)

A kinetic-empirical model for particle size distribution evolution during pulverised fuel combustion

Particle size is an essential parameter in pulverised fuel (PF) combustion as many of the problems or further areas of development in these systems are strongly influenced by the fuel and ash size distribution. This is particularly true for dynamic processes like pollutant formation, corrosion, erosion, slagging and fouling and the related decrease of the combustion and boiler efficiency. The evolution of particle size distribution (PSD) is a complex interaction of various competing chemical and physical transformations. Char oxidation, devolatilization and fragmentation, etc. represent first line physical and chemical transformations which can amend the particle size in the radiation zone. The evolution of the PSD represents the convolution of all of these physical and chemical transformations, operating over the entire size distribution. As a consequence, it is difficult to extract the relative importance of all competing size altering processes from the experiments. Various models such as break-up, thermal stress, shrinking core, percolation and particle-population model have been developed by incorporating numerous ash transformation mechanisms to predict the particle size evolution during the pulverised fuel combustion. The present work describes an adaptation of the numerical kinetic-based particle-population balance for predicting particle size evolution during PF combustion developed by Dunn-Rankin and Mitchell. The model is further simplified analytically and validated against experimental results. Several empirical parameters derived from the experiments are incorporated into the model. The resulting simplified PSD evolution model shows good agreement with literature and experimental results, with maximum 10% absolute standard deviation