Conditions Of High Contamination Research Articles

An agent-based modeling approach to estimate pathogen exposure risks from wheelchairs

Contributions of contaminated wheelchairs to nosocomial pathogen transmission are relatively unknown. Our aim was to develop a model predicting pathogen exposures for patients utilizing wheelchairs and estimate exposure reduction potential of wheelchair disinfection between rides. An agent-based model was informed by wheelchair location data from a connected 215-bed acute care and 250-bed long-term care facility. Simulated scenarios varied in frequencies of patient wheelchair contamination and wheelchair disinfection in between trips. Clostridioides difficile and methicillin-resistant Staphylococcus aureus concentrations on patient hands at the end of wheelchair trips were estimated. Exposure reductions due to disinfection, assuming low real-world efficacies (50%, 70%, and 90%), were compared. In the simulation, when few patients introduced contamination to wheelchairs, disinfection in between patients 50% of the time decreased baseline (no disinfection) estimated exposures for the 50th wheelchair rider by >99.999%. When patients had a 50% chance of being contaminated before the wheelchair ride, disinfection did not reduce exposures consistently. The efficacy of disinfection in between patient rides as an exposure mitigation strategy likely depends on the frequency of infected patient wheelchair use. During outbreak, high contamination conditions, disinfection, alone, is not enough to protect patients from wheelchair-mediated exposures.

Comparison of estimated norovirus infection risk reductions for a single fomite contact scenario with residual and nonresidual hand sanitizers

The purpose of this study was to relate experimentally measured log10 human norovirus reductions for a nonresidual (60% ethanol) and a residual (quaternary ammonium-based) hand sanitizer to infection risk reductions. Human norovirus log10 reductions on hands for both sanitizers were experimentally measured using the ASTM International Standard E1838-10 method, with modification. Scenarios included product application to: (1) inoculated fingerpads with 30- and 60-second contact times, and (2) hands followed by inoculation with human norovirus immediately and 4 hours later. Hand sanitizer efficacies were used in a mathematical model estimating norovirus infection risk from a single hand-to-fomite contact under low and high environmental contamination conditions. The largest log10 reductions for the residual and nonresidual hand sanitizers were for a 60-second contact time, reducing infection risk by approximately 99% and 85%, respectively. Four hours after application, the residual hand sanitizer reduced infection risks by 78.5% under high contamination conditions, whereas the nonresidual hand sanitizer offered no reduction. Log10 virus and infection risk reductions were consistently greater for the residual hand sanitizer under all scenarios. Further data describing residual hand sanitizer efficacy with additional contamination or tactile events are needed. Residual antinoroviral hand sanitizers may reduce infection risks for up to 4 hours.

ОЦЕНКА ЭФФЕКТИВНОСТИ БАКОВОЙ СМЕСИ НОВОГО ГЕРБИЦИДА ФЛЕКС С ГРАМИНИЦИДОМ ФЮЗИЛАД ФОРТЕ В ПОСЕВАХ СОИ

The results of the study of the biological and economic efficiency of the tank mixture Flex 1.5 l/ha + Fusilade Forte 1.5 l/ha in the post-emergence application in soybean crops are presented. The studies were conducted in 2018 according to the generally accepted methods in the plot experiment on the experi-mental field of The Far Eastern Research Institute of Plant Protection. It is established that this mixture has a high herbicidal activity (reduction of crude above - ground biomass by 99%) in respect of annual dicotyledonous and cereal weeds, as well as perennial dicotyledonous weeds, ensuring the purity of crops during the entire period of vegetation of the crop. Maximum toxic effect of a mixture of herbicides had on the most common in the coastal region and predominate in the cenosis of the dicotyledonous weed common ragweed and Asian copperleaf (reduction of mass by 91-100%). High sensitivity also showed lamb’s quarters, Asiatic dayflower, cockspur grass, Eriochloa villosa and dicotyledonous perennial species (field milk and creeping thistle), plants which at the time of treatment were in the rosette phase. As a standard, a mixture of Galaxy Top 1.7 l/ha + Fusilade Forte 1.5 l/ha was used, which showed high activity against annual and perennial dicotyledonous and annual cereal weeds. The increase in yield of soybean seeds in the Flex 1.5 l/ha + Fusilade Forte 1.5 l/ha was 1.04 t/ha with yield in the control-0.11 t/ha. In conditions of high contamination of crops with a wide range of broadleaved and cereal species characteristic of the South of the Far East, the use of tank mixtures of the new herbicide Flex with Fusilade Forte or other graminicides is very promising and should become an important element of the system of chemical protection of soybeans from weeds.

Реакция тканей трахеи на применение монофиламентного шовного материала

The article presents the results of experimental research on monofilament suture with different biodegradation periods when implanted into trachea tissue. The data obtained via histological, morphological and morphometric methods have been shown that application of monofilament suture material with long biodegradation period causes evident inflammatory reaction of trachea tissue, which persists through the entire period of monitoring, by 30th day the cell index value is 0.4±0.05. Unlike monofilament non-absorbable suture and suture with short biodegradation period, the application of which is marked with active proliferative process on the 14th day, the cell index is equal to 0,9±0.05 and 1,1±0,06 respectively. The obtained data demonstrate that application of monofilament suture material with long-term biodegradation period in tracheal surgery is non-desirable as the inflammatory process maintained by the suture material under conditions of high contamination by bacteria and active process of mucus formation will adversely affect healing. Application of suture with short-term biodegradation period in acute trachea injury treatment is optimal due to the fact that the organ tissue shows minimal reaction to suture and 60 days later the suture is completely absorbed, that means will not cause further complications.

Evaluation of activity of dichloroxylenol (1.2% w/v) on Staphylococcus aureus Oxoid 701/1 Lot 610254 and clinical isolates of Escherichia coli and Salmonella typhi

The activity of dichloroxylenol (1.2% w/v), a commercial disinfectant formulation called Tiscol, on Staphylococcus aureus Oxoid 701/1 Lot 610254 and clinical isolates ofEscherichia coli and Salmonella typhi was carried out using the kill kinetics and the Kesley – Sykes procedures. The study demonstrates that the effectiveness of dichloroxylenol (1.2% w/v) against the test bacteria was time and concentration dependent and markedly affected by the presence of organic matter. Dichloroxylenol (1.2% w/v) also showed slightly greater activity against S. aureus Oxoid 701/1 Lot 610254 than against Escherichia coli and Salmonella typhi, indicating a probable role for cell wall in the susceptibility of bacteria to dichloroxylenol (1.2% w/v). The kesley – Sykes results suggest that in conditions of high contamination or presence of organic matter such as food, blood or tissue particles, dichloroxylenol (1.2% w/v) at or above 6% v/v can be appropriate in disinfection. Key words: Dichloroxylenol (1.2% w/v), Kill kinetics, Kesley – Sykes method.

Innovación tecnológica: dispositivo para el rodillado, en tornos horizontales, de los muñones de ejes.

Consiste en el diseño de un dispositivo para el rodillado, adaptado a torno horizontal, para la deformación plástica superficial, mediante la aplicación de rodillos, para el reacondicionamiento de ejes dañados en los muñones producto del rozamiento durante su trabajo. Hay ejes que trabajan en condiciones de gran contaminación por suciedades y a bajas velocidades soportando altas solicitaciones, en contacto con cojinetes de deslizamiento lubricados por salpicadura. Después de dos o tres años de trabajo tienen que retirarse de explotación debido al alto deterioro de los muñones, a pesar de que interiormente no presentan ningún síntoma de fatiga. Después de realizarle el tratamiento superficial, con el dispositivo de la invención, tardan el doble de tiempo para que aparezcan los síntomas de deterioro. Se diseñó, fabricó y puso en explotación un dispositivo adaptado al torno horizontal. Se aplicó para la recuperación de los ejes de los carros jaula ferroviarios para el transporte de la caña de azúcar. El dispositivo garantiza la calidad de acabado superficial y resistencia al desgaste, sin afectar las exigencias de la seguridad ferroviaria.DOI: http://dx.doi.org/10.5377/nexo.v25i1.794 Nexo Revista Científica,Vol. 25, No. 01, pp.22-27/Junio 2012

Sedimentary diatoms along a temporal and spatial gradient of metal contamination

We examined changes at the community and population level of sedimentary diatoms over a wide temporal and spatial gradient of metal pollution encountered in cores from three lakes in the Abitibi mining region (Quebec, Canada). Diatom communities on the whole appeared to be very tolerant of metal contamination, as shown by diatom cell accumulation rates decreasing only under the most severe conditions of contamination, which were found from the 1930s to the 1980s in Lac Dufault (cadmium, up to 94 μg/g dry sediment; Cu, up to 8600 μg/g; Zn, up to 9000 μg/g). Under the moderate conditions of contamination observed in the other two lakes and in the most recent sediment of Lac Dufault, diatom cell accumulation rates tended to increase over values typical of the pre-mining period. However, there were increasing rearrangements of the community composition along the contamination gradient. Under moderate metal enrichment, the diatom community of Lac Vaudray experienced only subtle changes, with Cyclotella stelligera, albeit decreasing, remaining the dominant taxon. In the intermediately contaminated Lac Caron, several benthic taxa, noticeably Cymbella silesiaca and several Fragilaria species, rose in taxonomic importance. The most extreme contamination observed in Lac Dufault led to a severely impoverished community almost entirely represented by Achnanthes minutissima and Brachysira vitrea. With increasing levels of contamination, there was a shift from planktonic to benthic taxa and morphotypes and a consistent decrease in the siliceous stomatocysts/diatom frustules ratio. These trends suggest that littoral zones may represent an important refugium under conditions of high contamination. Responses to metal stress were in general more evident at the population than at the community level. Cyclotella stelligera and B. vitrea had a consistent negative and positive response, respectively, along the gradient and are the most promising indicators of metal pollution for this region.

Application of a Mass Balance Model To Assess In-Place Arsenic Pollution

A simple, steady-state mass balance model based on aquivalence as an equilibrium criterion is used to estimate chemical behavior in a lake and, together with the linear additivity principle (LAP), to quantify chemical contributions, especially that of in-place pollution. Since the model is linear, it is argued that chemical contributions from particular sources that vary spatially or temporally can be quantified and their effect isolated from total chemical dynamics. This is demonstrated by considering three loading scenarios for Moira Lake in eastern Ontario that has received elevated arsenic (As) inputs since 1866. Steady-state estimates of precontamination and high contamination conditions are generated by linearly scaling model results obtained with a unit inflow of 0.001 mg/L (unit profile)