3,963 results on '"SURFACE contamination"'
Search Results
2. Measuring complex SFG: Characterizing a phase reference.
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Xiong, Ziqing, Lynch, Rebecca G., Gubbins, Emma F., and Shultz, Mary Jane
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PHOTON upconversion , *ATMOSPHERIC aerosols , *SURFACE contamination , *BIOLOGICAL membranes , *REFERENCE sources - Abstract
Reactions and interactions at interfaces play pivotal roles in processes ranging from atmospheric aerosols influencing climate to battery electrodes determining charge–discharge rates to defects in catalysts controlling the fate of reactants to the outcome of biological processes at membrane interfaces. Tools to probe these surfaces at the atomic-molecular level are thus critical. Chief among non-invasive probes is the vibrational spectroscopy sum frequency generation (SFG). The complex signal amplitude generated by SFG requires techniques to interfere the unknown amplitude with a well-characterized one. An interferometric method is described to characterize the signal from any nonresonant reference material. The technique is demonstrated by measuring the phase of polycrystalline GaAs, chosen due to the strong signal and insensitivity to surface contamination. With a 515 nm visible field, the phase of GaAs is 54.5° ± 0.5°. The capability of choosing a reference based solely on its signal intensity enables probing a wide range of interfaces. [ABSTRACT FROM AUTHOR]
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- 2024
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3. SARS-CoV-2 transmission via maritime cold chains: A statistical analysis of nucleic acid detection results of cold chain food imported from Fuzhou ports
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Chen, Yuxiang, Zhao, Shuai, Xu, Yiyuan, Cai, Mingzhi, and Zhang, Guanbin
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- 2023
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4. Film swelling and contaminant adsorption at polymer coated surfaces: Insights from density functional theory.
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Frink, Laura J. Douglas, van Swol, Frank, Malanoski, Anthony P., and Petsev, Dimiter N.
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MONOMOLECULAR films , *DENSITY functional theory , *SURFACE coatings , *SURFACE contamination , *CORROSION prevention - Abstract
Designing coatings and films that can protect surfaces is important in a wide variety of applications from corrosion prevention to anti-fouling. These systems are challenging from a modeling perspective because they are invariably multicomponent, which quickly leads to an expansive design space. At a minimum, the system has a substrate, a film (often composed of a polymeric material), a ubiquitous carrier solvent, which may be either a vapor or liquid phase, and one or more contaminants. Each component has an impact on the effectiveness of coating. This paper focuses on films that are used as a barrier to surface contamination, but the results also extend to surface coatings that are designed to extract a low density species from the fluid phase as in liquid chromatography. A coarse-grained model is developed using Yukawa potentials that encompasses both repulsive and attractive interactions among the species. Classical density functional theory calculations are presented to show how contaminant adsorption is controlled by the molecular forces in the system. Two specific vectors through the parameter space are considered to address likely experimental manipulations that change either the solvent or the polymer in a system. We find that all the adsorption results can be unified by considering an appropriate combination of molecular parameters. As a result, these calculations provide a link between molecular interactions and film performance and may serve to guide the rational design of films. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Persistence of Structural Lubricity on Contaminated Graphite: Rejuvenation, Aging, and Friction Switches.
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Oo, Wai, Gao, Hongyu, Müser, Martin, and Baykara, Mehmet
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Atomic force microscopy ,Friction mechanisms ,Gold nanoislands ,Molecular dynamics ,Structural lubricity ,Surface contamination - Abstract
Using atomic force microscopy experiments and molecular dynamics simulations of gold nanoislands on graphite, we investigate why ultralow friction commonly associated with structural lubricity can be observed even under ambient conditions. Measurements conducted within a few days after sample synthesis reveal previously undiscovered phenomena in structurally lubric systems: rejuvenation, a drop in kinetic friction of an order of magnitude shortly after the onset of sliding; aging, a significant increase in kinetic friction forces after a rest period of 30 min or more; and switches, spontaneous jumps between distinct friction branches. These three effects are drastically suppressed a few weeks later. Imaging of a contamination layer and simulations provide a consistent picture of how single- and double-layer contamination underneath the gold nanoislands as well as contamination surrounding the nanoislands affect structural lubricity without leading to its breakdown.
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- 2024
6. Rapid virus inactivation by nanoparticles-embedded photodynamic surfaces.
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Zhang, Gengxin, Zhou, Jiewen, Lv, Quanjie, Yang, Ruihao, Zhang, Yuhan, Chu, Jing, Zhang, Haoran, Han, Yijun, Sun, Kang, Yuan, Congli, and Tao, Ke
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VIRUS inactivation , *VIRAL transmission , *SURFACE contamination , *REACTIVE oxygen species , *AIR filters , *METHYLENE blue - Abstract
[Display omitted] The persistent threat of viral epidemics poses significant risks to human health, highlighting the urgent need for antiviral surfaces to mitigate viral transmission through bioaerosols and surface contamination. However, there is still a scarcity of readily accessible antiviral coatings to address this critical concern. In this study, we demonstrate that photodynamic nanoparticle-embedded surfaces can swiftly inactivate both enveloped and non-enveloped viruses. We prepared core–shell structured methylene blue (MB)-loaded SiO 2 nanoparticles with a high reactive oxygen species (ROS) yield (0.47 ± 0.02). The superior ROS production was maintained after modifying these nanoparticles onto air filter fibers, likely due to the prevention of aggregation-caused quenching effects. Three viruses, including both enveloped and non-enveloped types, were rapidly inactivated within just 12 min (>6 log units) under medium light intensity (660 nm, 30 mW/cm2). Mechanistic studies revealed that envelope glycoproteins are the primary targets for this rapid inactivation. Thus, photodynamic nanoparticle-embedded surfaces offer a straightforward and adaptable strategy in the fight against viral epidemics. [ABSTRACT FROM AUTHOR]
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- 2025
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7. Simultaneous measurement of fentanyl, fentanyl analogues and other drugs of abuse by multiplex bead assay.
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Smith, J. P., Alexander-Scott, M., Striley, C., and Sammons, D.
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LIQUID chromatography-mass spectrometry , *DRUGS of abuse , *SURFACE contamination , *CONTROLLED substances , *CERAMIC tiles , *FENTANYL - Abstract
AbstractQuantification of illicit drugs and controlled substances, in urine or as surface contamination, is often performed using expensive analytical techniques such as liquid chromatography with tandem mass spectrometry (LC-MS/MS). A time and cost-effective semi-quantitative surface-wipe and urine screening multiplex immunoassay for fentanyl and its analogues was developed in this investigation. We previously created a surface wipe multiplex immunoassay for methamphetamine, caffeine, cocaine, tetrahydrocannabinol (THC) and oxycodone. This fluorescent covalent microsphere immunosorbent assay (FCMIA) is a competitive assay where drugs compete with protein-drug conjugates attached to microspheres for antibodies. It was assembled using a commercially available fentanyl antibody and protein-conjugate. Surface recovery from ceramic tiles was assessed by FCMIA, with results ranging from 26% for fentanyl to 60% for methamphetamine. Only fentanyl and its structurally similar analogues showed significant response to the fentanyl assay whereas, analogues structurally similar to carfentanil gave no response. Non-fentanyl drug assays did not appreciably detect fentanyl or its analogues. Overall, this method is a useful tool for assessing surface contamination and the effectiveness of decontamination by multiple drugs of abuse, potentially lowering workplace exposures. To broaden applicability, different antibodies or aptamers must be developed to detect structural differences found in classes of analogues such as carfentanil. [ABSTRACT FROM AUTHOR]
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- 2025
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8. Human Metapneumovirus: an emerging respiratory pathogen and the urgent need for improved Diagnostics, surveillance, and vaccine development.
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Akingbola, Adewunmi, Adegbesan, Abiodun, TundeAlao, Samuel, Adewole, Olajumoke, Ayikoru, Comfort, Benson, Akpevwe Emmanuella, Shekoni, Mayowa, and Chuku, Joel
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HEALTH facilities , *RESPIRATORY infections , *RESOURCE-limited settings , *SURFACE contamination , *SOCIAL distancing - Abstract
AbstractHuman Metapneumovirus (HMPV) is a re-emerging respiratory pathogen causing significant morbidity and mortality, particularly among young children, the elderly, and immunocompromised individuals. First identified in 2001, HMPV has since been recognised as a leading cause of acute respiratory tract infections (ARTIs) worldwide. Its transmission occurs through droplets, direct contact, and surface contamination, with crowded spaces and healthcare facilities serving as key environmental amplifiers. HMPV’s clinical manifestations, ranging from mild cold-like symptoms to severe pneumonia, often overlap with those of other respiratory pathogens like RSV and COVID-19, complicating timely diagnosis and management. Despite advancements in molecular diagnostics, the limited accessibility of these tools in low-resource settings presents a challenge. Preventive measures, such as hygiene practices and physical distancing, remain critical, as no approved vaccines or targeted antiviral therapies are currently available. However, promising innovations, including AI-guided vaccine design and portable diagnostic tools, highlight the potential for future breakthroughs. This article highlights the urgent need for enhanced surveillance, scalable diagnostics, and intensified research into vaccines and therapeutic strategies. By addressing these gaps, HMPV’s global burden can be significantly mitigated, improving outcomes for high-risk populations, and strengthening preparedness against respiratory virus outbreaks. [ABSTRACT FROM AUTHOR]
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- 2025
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9. 基于高光谱成像的复合绝缘子表面污秽成分识别方法.
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缪 金, 秦 军, 陈峻宇, 吴俊锋, 任 明, and 刘润宇
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COMPOSITE insulators ,POLLUTION measurement ,SURFACE contamination ,PRINCIPAL components analysis ,SUPPORT vector machines - Abstract
Copyright of Zhejiang Electric Power is the property of Zhejiang Electric Power Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2025
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10. Characteristics, source analysis, and risk assessment of organochlorine pesticide contamination in nearshore surface sediments of a tropical tourist island.
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Wang, Hongbing, Zhang, Lin, Yang, Feng, Yan, Li, Lin, Cong, and Shen, Cheng
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ENVIRONMENTAL protection ,ATMOSPHERIC deposition ,SUSTAINABLE tourism ,SURFACE contamination ,SEDIMENT sampling ,ECOLOGICAL risk assessment ,ORGANOCHLORINE pesticides ,DDT (Insecticide) - Abstract
Surface sediment samples were collected from the surrounding waters of the two largest tourist islands in Sanya, China, to compare and evaluate the sources, distribution, and ecological risks of 21 organochlorine pesticides (OCPs). The total concentration of OCPs ranged from 1.35 to 5.0 ng/g. Among the OCPs, ΣDDTs accounted for the largest proportion, followed by ΣHCHs. The concentrations of HCHs and DDTs from the west side of West Island were significantly higher than those from the east side, and fine-grained sediments exhibited a stronger adsorption effect on OCPs. Source analysis indicated that the area experienced new inputs of HCH pollutants, while historical residues of HCHs remained high. Residual OCPs are still widely present in the environment, transported mainly by river runoff, with a smaller portion originating from atmospheric deposition and ship paints. Ecological risk assessment results showed that factors occasionally causing adverse biological effects include Heptachlor epoxide, 4,4'-DDE, ΣDDT, Dieldrin, Endrin, and γ-HCH, while other factors rarely caused negative biological effects. Potential ecological effect evaluations indicated that stations SY03, SY04, SY06, and SY09 were classified as having moderate ecological effect levels, while other stations were classified as having no ecological effects. Strengthened investigation, monitoring, and control of pollutant sources in ecologically impacted areas are necessary. This study fills a data gap for the region and provides an academic foundation for environmental protection and the sustainable development of tourism resources. [ABSTRACT FROM AUTHOR]
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- 2025
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11. Efficiency boosting of 236 nm AlGaN-based micro-LEDs.
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Li, Hongbo, Lu, Shunpeng, Zhu, Licai, Sun, Wenchao, Bai, Jiangxiao, Hao, Jialong, Zhang, Shanli, Jiang, Ke, Shi, Zhiming, Jia, Yuping, Chen, Yang, Ben, Jianwei, Liu, Mingrui, Zang, Hang, Wu, Tong, Li, Dabing, and Sun, Xiaojuan
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SURFACE recombination , *STRAY currents , *POWER density , *SURFACE contamination , *LIGHT absorption - Abstract
In this study, 236 nm AlGaN-based deep ultraviolet (DUV) micro-LEDs with different sized P-contact areas are designed and fabricated, and the sidewalls are restored by a wet chemical treatment method with KOH solution. The results reveal that proper KOH treatment can effectively remove plasma damaged materials and clearly show the formation of m -plane facets. Compared with untreated micro-LEDs, the reverse leakage current of the treated micro-LEDs under −10 V decreases by up to 91.7% and the specific contact resistivity (SCR) reduces from 6.94 Ω cm2 to 0.07 Ω cm2. The underlying mechanism is that the KOH treatment removes the sidewall defects which lead to surface nonradiative recombination sites and surface leakage. Moreover, KOH treatment also removes contamination on the P+-GaN surface and leads to lower SCR. However, a much longer treatment also destructs the 20 nm P+-GaN layer, which results in higher voltage but less DUV light absorption. As a result, the peak light output power density increases from 2.12 W cm−2 to 4.01 W cm−2, representing an 89.2% increase. Efficient enhancement of micro-LEDs is anticipated to facilitate the development of DUV micro-LEDs for maskless lithography and high-capacity DUV non-line-of-sight communication. [ABSTRACT FROM AUTHOR]
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- 2025
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12. Enhanced decontamination of surface radioactive contamination using a hydrogel coating composited with Prussian blue.
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Yang, Man, Li, Zhanguo, Wang, Yi, and Lin, Xiaoyan
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PRUSSIAN blue , *RADIOACTIVE contamination , *SURFACE contamination , *LACQUER & lacquering , *HYDROGEN bonding , *GUAR gum - Abstract
In this study, a hydrogel-based strippable coating was expeditiously synthesised by employing hydrogen bonding between eco-compatible guar gum (GG), borax, and glycerol (Gly), thereby endowing the coating with excellent swelling capabilities and a high water retention capacity. This approach was specifically designed to navigate the intricate rheological management associated with strippable coating decontaminants. Through the incorporation of Prussian blue (PB), a material highly effective in adsorbing cesium (Cs), the solubility and diffusion of radionuclides within the hydrogel were significantly enhanced, thereby augmenting the decontamination efficacy of the hydrogel. The PB–GG–Gly composite demonstrated remarkable decontamination efficiencies, removing Cs from surfaces of glass, stainless steel, rubber, lacquer, and cement with percentages of 99.66%, 99.37%, 99.71%, 99.67%, and 83.83%, respectively. [ABSTRACT FROM AUTHOR]
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- 2025
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13. Research on surface charge accumulation characteristics of post-composite insulators in polluted environments.
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Huang, Ping, Yang, Guoting, Wei, Kequan, Huang, Junlin, and Zhang, Biao
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SURFACE conductivity , *SURFACE phenomenon , *WIND speed , *SIMULATION software , *SURFACE contamination , *SURFACE charges - Abstract
Post insulators are commonly used in DC converter stations. Studying their contamination accumulation characteristics is crucial for reducing pollution flashover accidents and ensuring power systems' safe and stable operation. This paper takes the FZSMW-75/8-Z post-composite insulator as the research object. Natural contamination accumulation tests are carried out under DC voltage. Group sampling of contamination accumulation on the upper and lower surfaces of insulator umbrella skirts resulted in a greater accumulation of dirt on the lower surface of the insulator skirt than on the upper surface. Based on the results of natural contamination accumulation tests, an FZSMW-75/8-Z insulator model is developed using COMSOL multiphysics simulation software. The simulation results are basically consistent with the natural contamination accumulation test results, verifying the rationality of the simulation model. Subsequently, aiming at the phenomenon of surface conductivity differences and surface charge accumulation caused by uneven contamination on the insulator surface, the surface charge accumulation situation is characterized by changes in surface charge density distribution. Analysis is carried out on how wind speed, the diameter of contaminating particles, and the inclination of wind direction impact the distribution of surface charge density on post-composite insulators. The results show that when the wind direction is fixed, the insulator's surface charge density has a positive association with the wind velocity, and it first declines and then ascends as the diameter of the contaminated particles enlarges. When the wind direction changes, the surface charge density of the insulator slowly rises with the increase in airflow inclination. [ABSTRACT FROM AUTHOR]
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- 2025
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14. A Simplified Non‐Hertzian Wheel‐Rail Adhesion Model Under Interfacial Contaminations Considering Surface Roughness.
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Wang, Zhaoyang, Wu, Bing, and Huang, Jiaqing
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HERTZIAN contacts , *SURFACE roughness , *SURFACE contamination , *AXLES , *ELASTOHYDRODYNAMIC lubrication , *ROLLING contact - Abstract
The accuracy and efficiency of the wheel‐rail adhesion model are important to the wheel‐rail rolling contact issues. The purpose of this study is to develop a simplified non‐Hertzian wheel‐rail adhesion model under interfacial contaminations to predict the wheel‐rail adhesion coefficient. Firstly, a non‐Hertzian full elasto‐hydrodynamic lubrication (EHL) model was developed and applied to determine the wheel‐rail contact pressure and film thickness under interfacial contaminations. Then, the empirical formula of central film thickness available to non‐Hertzian wheel‐rail normal contact relating to train speeds, axle loads and material parameters were proposed based on a large number of non‐Hertzian full EHL simulation for smooth surface under interfacial contaminations using linear regression. The empirical non‐Hertzian central film thickness formula and minimum film thickness formula for wheel‐rail contact obtained in this paper show certain differences from the formulas based on Hertzian contact. Using the proposed non‐Hertzian central film thickness formula, a simplified non‐Hertzian wheel‐rail contact adhesion model was developed, and the adhesion coefficient was obtained at different speeds and compared with the field test data. The numerical results showed good agreement with field test data. [ABSTRACT FROM AUTHOR]
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- 2025
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15. Infrared Thermography of Turbulence Patterns of Operational Wind Turbine Rotor Blades Supported With High‐Resolution Photography: KI‐VISIR Dataset.
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Chaudhuri, Somsubhro, Stamm, Michael, Lapšanská, Ivana, Lançon, Thibault, Osterbrink, Lars, Driebe, Thomas, Hein, Daniel, and Harendt, René
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CONVOLUTIONAL neural networks ,WIND turbine blades ,LAMINAR flow ,SURFACE contamination ,TURBULENT flow - Abstract
With increasing wind energy capacity and installation of wind turbines, new inspection techniques are being explored to examine wind turbine rotor blades, especially during operation. A common result of surface damage phenomena (such as leading edge erosion) is the premature transition of laminar to turbulent flow on the surface of rotor blades. In the KI‐VISIR (Künstliche Intelligenz Visuell und Infrarot Thermografie—Artificial Intelligence‐Visual and Infrared Thermography) project, infrared thermography is used as an inspection tool to capture so‐called thermal turbulence patterns (TTPs) that result from such surface contamination or damage. To complement the thermographic inspections, high‐resolution photography is performed to visualise, in detail, the sites where these turbulence patterns initiate. A convolutional neural network (CNN) was developed and used to detect and localise turbulence patterns. A unique dataset combining the thermograms and visual images of operational wind turbine rotor blades has been provided, along with the simplified annotations for the turbulence patterns. Additional tools are available to allow users to use the data requiring only basic Python programming skills. [ABSTRACT FROM AUTHOR]
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- 2025
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16. Reusable Tourniquets as Potential Transmitters of Infection: A Microbiological Analysis.
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Szymczyk, Julia, Kurpas, Monika, Krasiński, Bartosz, Zorena, Katarzyna, and Mędrzycka-Dąbrowska, Wioletta
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BACTERIAL contamination ,MICROBIAL contamination ,CATHETER-related infections ,BACTERIAL cell surfaces ,SURFACE contamination - Abstract
Introduction: Healthcare-associated infections (HAIs) pose a significant global challenge, resulting in prolonged hospital stays, higher healthcare costs, and increased morbidity and mortality rates. Reusable medical equipment, such as tourniquets, represents a potential vector for infection transmission. Despite frequent use and close contact with patients' skin, infection control protocols often overlook these devices. This study examines microbial contamination on the surface of reusable tourniquets in both emergency department and operating theatre settings. Methods: A cross-sectional study was conducted between March and September 2024 in Gdansk, Poland. Samples from tourniquets used in the emergency department and the operating theatre were collected after an indefinite period, 14 days, and 28 days. Bacterial contamination on the surfaces of the tourniquets was measured using Columbia agar blood medium and expressed as colony-forming units (CFUs) per cm
2 . Results: Significant bacterial loads were detected on reusable tourniquets, with contamination levels varying by location and duration of use. The average number of CFU/cm2 across all stages of this study was 545 CFU/cm2 for the emergency department and 101 CFU/cm2 for the operating theatre. Tourniquets used in the emergency department exhibited higher bacterial counts compared to those from the operating theatre, which showed a greater diversity of bacterial species. These findings underscore the need to revise infection control protocols for reusable tourniquets. Conclusion: This study provides critical data that may influence future policy changes aimed at reducing the risk of HAIs through the improved management of reusable medical devices. [ABSTRACT FROM AUTHOR]- Published
- 2025
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17. Modeling and predicting caffeine contamination in surface waters using artificial intelligence and standard statistical methods.
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Peixoto, Luis Otávio Miranda, da Costa Pereira, Jorge Luis Gabriel Ferreira da Silva, Fernandes, Cristovão Vicente Scapulatempo, Centeno, Jorge Antonio Silva, and de Azevedo, Júlio César Rodrigues
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ARTIFICIAL neural networks ,WATER pollution ,SURFACE contamination ,ARTIFICIAL intelligence ,WATER quality - Abstract
Caffeine, considered an emerging contaminant, serves as an indicator of anthropic influence on water resources. This research employs various modeling techniques, including Artificial Neural Networks (ANN), Random Forest (RF), and more, along with hybrid and ensemble methods, to predict caffeine concentrations (in regression and classification scenarios) using readily available water quality parameters. The results indicate Ensemble-RF as the most effective method for estimating caffeine concentrations, while classification scenarios highlight Ensemble-RF, ANN, and Ensemble-ANN as promising methodologies for predicting contamination levels. This study offers a valuable tool for swiftly assessing caffeine contamination in water, leveraging easily obtainable data, with implications for safeguarding water resource systems. [ABSTRACT FROM AUTHOR]
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- 2025
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18. Reducing the Radioactive Surface Contamination Level of Cobalt-60-Contaminated Material with PVA-Glycerol-EDTA Combination Gel.
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Anggakusuma, Rezky, Utama, Gemilang Lara, Zain, Muhammad Khoirul, and Megasari, Kartini
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NUCLEAR facility decommissioning ,SURFACE contamination ,RADIOACTIVE contamination ,POLYVINYL alcohol ,SURFACES (Technology) - Abstract
Decommissioning of nuclear facilities can be performed in stages. One of the stages and processes in decontamination is the decontamination process before dismantling or facility area recovery activities. Decontamination can be performed using various methods, primarily physical and chemical. One chemical method involves using a gel made of polymers for decontamination. In this study, a gel consisting of a mixture of 15 g polyvinyl alcohol (PVA), 15 mL of glycerol, and 2 g Na-EDTA was dissolved in 100 mL. The three materials were dissolved in hot conditions until they dissolved, and a gel was formed. The formed gel was applied to the material contaminated by Co-60 with a radioactivity of 81 µCi, as much as 5 µL. The decontamination radioactive efficiency test results range from 53% to 98%, with the highest decontamination efficiency observed on glass media. This study also showed that higher EDTA concentrations can increase the ability of the PVA-glycerol gel to absorb and bind Co. This study also found that decontamination efficiency was influenced by the type of contaminated material and the concentration of EDTA. It can be concluded that gels with a composition of PVA, glycerol, and EDTA can reduce the level of contamination on the surface of materials made of glass, ceramics, and metal plates. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
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19. Mercury accumulation and transformation in the surface sediments of urban waterscapes in the megacity of Shanghai, China.
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Deng, Hong, Li, Xin, Wang, Yongjie, Wen, Qian, and Wong, Ming Hung
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SUBURBS ,CITIES & towns ,LIFE sciences ,SURFACE contamination ,MEGALOPOLIS ,ATMOSPHERIC mercury - Abstract
Purpose: The effects of urbanization on the distribution and methylation of mercury (Hg) in local-scale aquatic ecosystems have been poorly characterized. Here, we aim to characterize and compare total Hg (THg) concentrations and methylmercury (MeHg) production in sediments in waterscapes across the megacity of Shanghai, China, and evaluate the impacts of organic matter and Hg inputs on changes in sediment MeHg production during reduction and reoxidation. Materials and methods: Surface sediments were collected in summer and winter from 15 lakes in parks and 17 rivers located in central urban or suburban areas, and THg, MeHg and environmental parameters were measured. In addition, two different incubation series were conducted under different redox conditions over a short period (21 or 56 days). Results and discussion: Concentrations of THg and MeHg generally increased in sediments from rural to urban areas, with abnormally high levels at several urban sites. The historical point-source anthropogenic Hg releases could be important contributors to the increases, as reflected by the marked deviations from the regression line between Hg and loss on ignition. Furthermore, both litterfall organic matter and Hg inputs strongly promoted net MeHg production in sediments over a short period, resulting in potential MeHg bioaccumulation in waterscapes. Conclusions: Our study suggested that urbanization in the Shanghai area resulted in Hg loading in central urban areas. However, the low %MeHg but abnormally elevated Hg levels observed at some sites in the field indicated that the potential ecological risks of Hg could be limited, even with new Hg inputs. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
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20. Comparison of closed‐system transfer devices to compound cytotoxic medicines in a hospital pharmacy compounding unit.
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Smith, Evonne Katherine
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SURFACE contamination , *JUSTIFICATION (Ethics) , *ONCOLOGY pharmacy , *HOSPITAL pharmacies , *QUALITY assurance - Abstract
Background Aim Method Results Conclusion The use of a closed system transfer device (CSTD) is recommended when compounding hazardous cytotoxic medicines for operator and environmental protection. The hospital pharmacy compounding unit has used the CSTD PhaSeal since 2014. Recent evidence suggests an alternative CSTD, Equashield, may be a suitable alternative.To determine if Equashield provides any advantages financially, in compounding time, rubber bung contamination, cytotoxic medicine surface contamination, staff satisfaction, and work health and safety benefits when compared to PhaSeal.CSTD PhaSeal was compared to Equashield by performing a financial cost comparison, time in motion study to compare compounding time, evaluation of product contamination rates and cytotoxic surface contamination levels, work health and safety (WH&S) review and staff satisfaction survey. This project was exempt due to the local policy requirements that constitute research by the Children's Health Queensland Research Ethics Committee (Reference no: EX/23/QCHQ/97690). The justification for this ethics exemption was as follows: the study conformed with the Ethical considerations in quality assurance and evaluation activities and met local requirements for a quality assurance activity and did not involve any assessment of staff. Informed consent was obtained from all staff via verbal explanation of the project and their voluntary participation. Staff consented via completion of the voluntary survey.The cost to compound using Equashield instead of PhaSeal was increased by AUD $4684 over a 6‐month period, with a compounding time saving benefit of approximately 1 min per product. Product contamination by rubber stopper core was 16 per 100,000 products using Equashield. Surface cytotoxic contamination levels remained undetectable before and after the comparison. Staff preferred Equashield and a WH&S product review determined Equashield required less torque and force during use and may reduce repetitive strain injury.Equashield performed better in time to compound, rate of product contamination, staff satisfaction and WH&S assessment. The cost of Equashield was greater; however, Equashield demonstrated benefits over Phaseal in other areas of comparison, which could potentially offset the cost increase. The pharmacy demonstrated Equashield may be a suitable alternative to PhaSeal. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Effects of anthranilic diamide insecticides on metamorphosis in the common toad Rhinella arenarum (Hensel, 1867) at concentrations found in aquatic environments.
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Peña, Shirley Vivian Daniela Fonseca and Brodeur, Julie Céline
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CHLORANTRANILIPROLE , *NEONICOTINOIDS , *ENDOCRINE disruptors , *SURFACE contamination , *WATER pollution , *INSECTICIDES , *AMPHIBIANS - Abstract
Anthranilic diamides (AD) are a modern class of insecticides used as alternatives to pyrethroids and neonicotinoids, particularly against lepidopteran pests. Despite their widespread use and presence in surface waters, little is known regarding their effects on amphibians. The aim of this study was to examine the effects of environmentally-relevant concentrations of AD insecticides chlorantraniliprole (CHLO) and cyantraniliprole (CYAN) on metamorphosis of the toad Rhinella arenarum. Tadpoles were exposed to CHLO or CYAN at concentrations ranging from 5 and 5000 µg/L from stage 27 until metamorphosis completion. Both insecticides produced a non-monotonic acceleration of the time required for individuals to progress through development and a decrease in the proportion of individuals completing metamorphosis, although a delay in metamorphosis was also observed at 5 µg/L of CHLO. Snout-vent length and body weight of metamorphosed toads were not markedly affected by either insecticide. CHLO was more toxic than CYAN, with a lowest observed effect concentration (LOEC) for CHLO on time to metamorphosis defined as 5 µg/L compared to 5000 µg/L for CYAN. The LOEC for reduced metamorphic success defined as 50 µg/L for CHLO compared to 500 µg/L for CYAN. As most effects occurred after stage 39, when metamorphosis depends upon thyroid hormones, it is conceivable that that AD insecticides act as endocrine disruptors. These findings suggest that contamination of surface waters with CHLO and CYAN may disrupt amphibian development in the wild and warrant further research to investigate the possibility of endocrine-disruption by ADs. [ABSTRACT FROM AUTHOR]
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- 2024
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22. Risk assessment of groundwater and surface water contamination by waste leachate from the Guercif open dump, Morocco.
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Zamani, Nora, Merzouki, Mohammed, Talbi, Fatima Zahra, Najy, Mohamed, and Janati-Iddrissi, Abdellatif
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METALS , *WATER pollution , *WATER table , *SURFACE contamination , *LEACHATE - Abstract
This study examines the physicochemical parameters of leachate from an uncontrolled landfill in the town of Guercif before its remediation, and its impact on the Tafrata aquifer located beneath the landfill and the adjacent Oued Moulouya surface waters. The results revealed significant organic pollution in the raw leachate, characterised by high levels of BOD5 (13,141.56 mg O2/l), COD (89,821.38 mg/L), nitrate, nitrite, and orthophosphate. Additionally, elevated concentrations of metallic elements (Co: 3 mg/L, Cr: 11.7 mg/L, Pb: 3 mg/L) exceeded recommended standards. The analysis also detected high pollutant concentrations in groundwater (e.g. BOD5 at P1: 176.65 mg O2/L), COD at P1: 589.25 mg/L), nitrate at P1: 57.08 mg/L, nitrite at P1: 0.86 mg/L, ammoniacal nitrogen at P1: 1.112 mg/L) and surface (BOD5: 420.14 mg O2/L, COD: 797.86 mg/L, nitrate, nitrite, orthophosphate). These findings indicate significant percolation of polluted leachate into the natural bedrock. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Reducing the effects of clogging and surface wear on the radiative properties of concrete blocks produced with recycled glass by incorporating titanium dioxide nanoparticles.
- Author
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Preve, Arthur Reichert Damian, de Melo, João Victor Staub, Marinoski, Deivis Luis, and Manfro, Alexandre Luiz
- Subjects
- *
TITANIUM dioxide nanoparticles , *CONCRETE blocks , *SURFACE contamination , *GLASS recycling , *MECHANICAL wear - Abstract
This study aimed to demonstrate how incorporating titanium dioxide nanoparticles into concrete blocks made with recycled glass mitigates the effects of clogging and surface wear on pavement radiative properties. Using a reference concrete, four variants were formulated: with colourless, green, and amber glass, and a photocatalytic concrete with colourless glass. Three accelerated processes were applied to the concrete blocks in field: clogging, wear, and clogging on a worn surface. After each cycle of clogging and/or wear, solar reflectance and thermal emittance were measured to calculate the solar reflectance index (SRI). Surface clogging decreased the SRI for all concrete types, albeit less for photocatalytic concrete with colourless glass. SRI decreased with wear until a mean texture depth (MTD) near 0.80 mm, where a stabilisation trend was noted across all concretes. Photocatalytic concrete with colourless glass consistently showed the highest SRI values relative to the MTD. Clogging on worn surfaces indicated superior radiative properties for photocatalytic concrete with colourless glass at surface contamination degree (SCD) values less than 40%. In conclusion, conventional concretes with glass had inferior radiative properties compared to reference concrete. However, photocatalytic concrete with colourless glass showed superior radiative properties, indicating that nano-TiO2 addition reduced clogging and wear effects. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Microplastics in the Delaware River Estuary: Mapping the Distribution and Modeling Hydrodynamic Transport.
- Author
-
Akbari, Elham, Powers, Lacey, Shah, Tanishka, Suri, Rominder, Jedrusiak, Scott, Bransky, Jacob, Chen, Fanghui, and Andaluri, Gangadhar
- Subjects
- *
WATER pollution , *MICROPLASTICS , *WATERSHEDS , *SURFACE contamination , *PLASTIC marine debris , *PLANT health - Abstract
Microplastic pollution poses a significant threat to the ecosystem, encompassing not only aquatic organisms but also plants and human health due to their capacity for bioaccumulation, driven by their minute size and persistence. Although previous research predominantly centered on the effects of microplastics in ocean environments, it is vital to recognize that their ultimate destination is often rivers and estuaries, serving as more precise point sources for analysis. This research focuses on a comprehensive investigation involving the monitoring and modeling of microplastic distribution and concentration within the Delaware estuary. Grab and net sampling methods were employed across Philadelphia, Camden, and Wilmington, Delaware, to examine the distribution, concentration, and characteristics of these pollutants. The findings indicate that microplastic's diameters varied from 90 µm to 1000 µm along the Delaware River, with 71% of particles in grab samples under 500 µm. In contrast, 66% of particles in net samples exceeded 500 µm. Moreover, concentrations in grab samples ranged from 0.24072 to 7.08 particles/m3, whereas net samples showed significantly lower concentrations, ranging from 0.000059 to 0.00268 particles/m3. The investigation discovered a range of plastic compounds, most notably polyester, polypropylene, and polyethylene, with fibers being the most common shape. Furthermore, the concentration and composition of microplastics were closely linked to urbanization, population density, and industrial activities. Analysis using the Delaware River Basin Commission's 3D hydrodynamics model revealed that microplastics predominantly stayed in upper water layers for up to 20 days and moved toward the opposite bank from their release point, influenced by current dynamics. These findings not only enhance our comprehension of microplastic pollution in freshwater ecosystems but also establish a foundational framework for future research aimed at developing effective management and remediation strategies, particularly for ecosystems near to the Delaware estuary. This study provides essential data that can inform policy decisions and conservation initiatives designed to reduce the environmental impact of microplastics. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Fibrin clot adherence on cleaned and decontaminated titanium abutment surfaces: An in vitro study.
- Author
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Ulusoy, Habibe Öztürk, Ercan, Esra, Özatik, Orhan, and Tunalı, Mustafa
- Subjects
- *
PLATELET-rich fibrin , *THROMBOSIS , *SURFACE contamination , *SCANNING electron microscopy , *STERILIZATION (Disinfection) - Abstract
Statement of Problem: Osseointegration is now primarily established, but soft tissue integration is still susceptible to failure and problematic on implant surfaces. So, implant dentistry is increasingly focusing on improving peri‐implant soft tissue integration. Purpose: The present study aimed to evaluate the blood fibrin clot formation and adhesion on the abutment after cleaning and decontamination and determine the suitable abutment surface associated with fibrin clot attachment. Materials and Methods: Forty‐two abutments (14 per group) were used in the present study: a brand‐new (BN), contaminated with biofilm (CO) and decontaminated with an enzymatic cleaner and autoclave sterilization (DEC). For a fibrin clot, 9 mL of whole human blood and abutments was centrifuged at 2700 rpm for 12 min. Clots were divided into two parts for histomorphometry and scanning electron microscopy (SEM) analysis. Twelve abutments disconnected from the clot and two not treated with blood were observed under SEM. Results: Residual debris and biofilm were observed on the abutment surface in the CO group but not in other groups. Healthy and organized fibrin clots formed on all abutments. The fibrin extension areas are distributed uniformly in BN and DEC groups but irregularly in CO. The surface percentage of the fibrin clot extensions was 41.76% ± 6.73, 26.99% ± 6.40, and 37.83% ± 9.72 for the BN, CON, and DEC groups, respectively. The blood clot‐attached areas in the CO group were statistically lower than the other groups. No difference was observed between the BN and DEC groups. Conclusions: This study confirmed that surface contamination could influence blood clot attachment on the abutment surfaces. Cleaning and sterilization can have a favorable effect on soft tissue healing on abutment surfaces. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Detection of SARS-CoV-2 in Environment: Current Surveillance and Effective Data Management of COVID-19.
- Author
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Nadzirah, Sh., Mohamad Zin, Noraziah, Khalid, Arif, Abu Bakar, Nur Faizah, Kamarudin, Siti Syafiqah, Zulfakar, Siti Shahara, Kon, Ken Wong, Muhammad Azami, Nor Azila, Low, Teck Yew, Roslan, Roharsyafinaz, M Nassir, M. Nizar Hadi, Alim, Anis Amirah, Menon, P. Susthitha, Soin, Norhayati, Gopinath, Subash C. B., Abdullah, Huda, Sampe, Jahariah, Zainal Abidin, Hafzaliza Erny, Mohd Noor, Siti Nurfadhlina, and Ismail, Ahmad Ghadafi
- Subjects
- *
SARS-CoV-2 , *VIRAL transmission , *SURFACE contamination , *DATA management , *ENVIRONMENTAL management - Abstract
Since diagnostic laboratories handle large COVID-19 samples, researchers have established laboratory-based assays and developed biosensor prototypes. Both share the same purpose; to ascertain the occurrence of air and surface contaminations by the SARS-CoV-2 virus. However, the biosensors further utilize internet-of-things (IoT) technology to monitor COVID-19 virus contamination, specifically in the diagnostic laboratory setting. The IoT-capable biosensors have great potential to monitor for possible virus contamination. Numerous studies have been done on COVID-19 virus air and surface contamination in the hospital setting. Through reviews, there are abundant reports on the viral transmission of SARS-CoV-2 through droplet infections, person-to-person close contact and fecal-oral transmission. However, studies on environmental conditions need to be better reported. Therefore, this review covers the detection of SARS-CoV-2 in airborne and wastewater samples using biosensors with comprehensive studies in methods and techniques of sampling and sensing (2020 until 2023). Furthermore, the review exposes sensing cases in public health settings. Then, the integration of data management together with biosensors is well explained. Last, the review ended with challenges to having a practical COVID-19 biosensor applied for environmental surveillance samples. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Urushiol-Based Coating with High Surface Hydrophilicity for Easy-Cleaning of Oil Pollutants.
- Author
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Ye, Yuansong, Shi, Huiping, Zhang, Yuchi, Xia, Jianrong, Shiu, Bing-Chiuan, and Fang, Run
- Subjects
- *
CONTACT angle , *POLYETHYLENE glycol , *SURFACE contamination , *SURFACE coatings , *MARINE engineering - Abstract
Urushiol is recognized as a sustainable coating material with superior properties; however, it faces significant challenges in applications such as petrochemicals and marine engineering due to surface oil contamination. This study aimed to enhance the cleanability of urushiol-based coatings through hydrophilic modification. Polyethylene glycol monooleate (PEGMO) was identified as an appropriate hydrophilic macromonomer and utilized as a modifier to develop a novel urushiol-based coating, termed P(U-PEGMO), via thermal curing. The results indicated that copolymerization occurred between urushiol and PEGMO during the curing process, forming a stable urushiol copolymer with favorable compatibility. The incorporation of PEGMO greatly improved the surface hydrophilicity of the coatings, as evidenced by a reduction in the water contact angle to below 30° when the modifier content reached 30% or higher, demonstrating a high degree of surface hydrophilicity. This enhanced property imparted the modified coating with underwater superoleophobicity and reduced oil adhesion, thereby facilitating the removal of oil. The cleaning performance was evaluated using a simple water rinsing method, after which, less than 2.5 wt% of oil residues remained on the surface of the modified coating. The high hydrophilicity is considered responsible for the coating's easy-cleaning capability. In addition, the modified coatings exhibited improved flexibility and impact resistance, albeit with a slight decrease in hardness. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. 2M NaCl by XPS using monochromatic Al Kα x rays.
- Author
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Zahra, Khadisha M., Soomary, Liam A. J., and Counsell, Jonathan D. P.
- Subjects
POROUS materials ,X-rays ,ULTRAHIGH vacuum ,SURFACE contamination ,ION sources - Abstract
Cryo-XPS enables the study of many substances that are unsuitable for standard XPS analysis, such as moderately volatile liquids, biological samples, porous materials, and polymeric materials that may outgas significantly under ultrahigh vacuum conditions. In this article, XPS spectra of a 50 μl frozen droplet of 2M sodium chloride solution (NaCl) in Millipore water purified to 18.2 MΩ cm at 25 °C were obtained using an Al Kα (1486.6 eV) source with a quartz (1010) crystal monochromator through first order diffraction and irradiating the sample at 54.7° to the surface normal. The sample was sputter cleaned using a Gas Cluster Ion Source pre-acquisition to remove the minor layer of adventitious carbon contamination on the surface. Spectra of the principal lines include Na 1s, O 1s, and Cl 2p. Spectra of O KLL, Na KLL, Cl 2s, Na 2s, Na 2p, O 2s, and valence band were also acquired. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Analysis of silver metal with a Thermo Scientific K-Alpha XPS instrument at 50 and 200 eV pass energies.
- Author
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Kulbacki, Braxton J., Jafari, Samira, Dean, Annika M., Ko, Steven, Linford, Matthew R., and Major, George H.
- Subjects
SURFACE contamination ,SCIENTIFIC apparatus & instruments ,SURFACE analysis ,METAL analysis ,X-rays - Abstract
Silver metal was analyzed by x-ray photoelectron spectroscopy using a Thermo Scientific K-Alpha instrument with an Al K
α x-ray source (1486.6 eV). The silver survey spectrum and high-resolution Ag 3d, Ag M4 N45 N45 , Ag M5 N45 N45 , Ag 3p, O 1s, C 1s, Ar 2p, Ag 4p, and Ag 4s narrow scans were obtained. The sample analyzed is the standard instrument calibration silver foil mounted inside the analysis chamber of the K-Alpha. Sputtering with monoatomic Ar+ was performed prior to analysis to remove surface contamination. Narrow and survey scans were collected at 50 and 200 eV pass energy, respectively. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
30. Predicted Potential for Aquatic Exposure Effects of Per- and Polyfluorinated Alkyl Substances (PFAS) in Pennsylvania's Statewide Network of Streams.
- Author
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Breitmeyer, Sara E., Williams, Amy M., Conlon, Matthew D., Wertz, Timothy A., Heflin, Brian C., Shull, Dustin R., and Duris, Joseph W.
- Subjects
CONVOLUTIONAL neural networks ,FLUOROALKYL compounds ,ENVIRONMENTAL health ,SURFACE contamination ,WATER pollution - Abstract
Per- and polyfluoroalkyl substances (PFAS) are contaminants that can lead to adverse health effects in aquatic organisms, including reproductive toxicity and developmental abnormalities. To assess the ecological health risk of PFAS in Pennsylvania stream surface water, we conducted a comprehensive analysis that included both measured and predicted estimates. The potential combined exposure effects of 14 individual PFAS to aquatic biota were estimated using the sum of exposure-activity ratios (Σ EARs) in 280 streams. Additionally, machine learning techniques were utilized to predict potential PFAS exposure effects in unmonitored stream reaches, considering factors such as land use, climate, and geology. Leveraging a tailored convolutional neural network (CNN), a validation accuracy of 78% was achieved, directly outperforming traditional methods that were also used, such as logistic regression and gradient boosting (accuracies of ~65%). Feature importance analysis highlighted key variables that contributed to the CNN's predictive power. The most influential features highlighted the complex interplay of anthropogenic and environmental factors contributing to PFAS contamination in surface waters. Industrial and urban land cover, rainfall intensity, underlying geology, agricultural factors, and their interactions emerged as key determinants. These findings may help to inform biotic sampling strategies, water quality monitoring efforts, and policy decisions aimed to mitigate the ecological impacts of PFAS in surface waters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Assessment of pesticide contamination in hill reservoirs: combination of a rainfed farming survey and water multiresidue monitoring (Lebna watershed, Cap Bon, Tunisia).
- Author
-
Dahmeni, Ghada, Grünberger, Olivier, and Chaabane, Hanène
- Subjects
PESTICIDE residues in food ,DRINKING water standards ,WATER pollution ,PESTICIDE pollution ,SURFACE contamination - Abstract
Due to Mediterranean climatic conditions, traditional pluvial agrosystems are widespread along the southern Mediterranean shore and were previously thought to have minimal impact on surface water resources due to low agricultural input levels. However, current pesticide applications are now considered to contribute significantly to the contamination of surface water resources, which may result in severe impacts on biodiversity and the environment. This study examined the presence and mobility risk of pesticides in the surface waters of the Lebna watershed in northeastern Tunisia, a rainfed Mediterranean agricultural region. Water samples were collected from eight hilly reservoirs and the Lebna dam over three farming seasons (2017–2018, 2019–2020, and 2020–2021) and analyzed for 469 pesticide active ingredients (PAIs). According to the field questionnaire, local farmers used 44 PAIs, including 15 herbicides, 21 fungicides, and 8 insecticides. Seventeen pesticide molecules were detected, with glyphosate (1.73 µg L
−1 ) and 2,4-D (0.23 µg L−1 ) being the most prevalent. Despite toxicity indexes, which classify a threat of pesticides as low to moderate, their concentrations may now exceed European standards for drinking water and endanger aquatic life. According to the Pesticide Impact Rating Index (PIRI), PAIs can be organized into three mobility risk categories: medium to high for 2,4-D and glyphosate, low for five PAIs, and very low for 13 undetected PAIs. This work provides the first assessment of pesticide contamination in surface waters of the Cap Bon region, raising concerns about water quality in a low-input agrochemical system and increasing interest in similar contexts. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
32. Efficacy of Antimicrobial Dry Fog in Improving the Environmental Microbial Burden in an Inpatient Ward.
- Author
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Jalali, Yashar, Kološová, Andrea, Džupa, Karol, Pavlovič, Pavol, Jalali, Monika, Rácek, Peter, Zicháčková, Nikola, Kyselovič, Ján, Vasiková, Adriana, Glodová, Klaudia, and Payer, Juraj
- Subjects
AIRBORNE infection ,SURFACE contamination ,INFECTION control ,AIR sampling ,SHOWROOMS - Abstract
Background/Objectives: In healthcare environments with high microbial loads, effective infection control measures are critical for reducing airborne and surface contamination. One of the novel modalities in the achievement of these goals is the use of antimicrobial mists, such as droplets, in the form of dry fog. Although the usage of dry fog in the disinfection of contained healthcare microenvironments is well known, the effect of such a system in terms of a meaningful reduction in the microbial burden in an open inpatient ward is unclear. Our objective was to assess the impact of scheduled dry fogging on microbial reduction in such settings. Methods: We collected air and surface samples from rooms receiving daily, biweekly, or no fogging (controls) over six months, establishing the baseline contamination and evaluating the reduction trends in treated rooms. The "reduction effect" was measured by tracking microbial isolation trends before and after treatment, while the "degree of reduction" assessed differences across rooms with varied disinfection schedules. Results: The results indicate that scheduled dry fogging significantly reduced microbial loads in treated rooms, especially with daily disinfection (SE = 64.484, p = 0.002). The airborne contamination in treated rooms showed a strong downward trend over time (SE = 19.192, p < 0.001). Surface contamination remained challenging due to frequent recontamination; however, treated rooms exhibited a consistent reduction in microbial presence (SE = 2.002, p = 0.010), confirming dry fogging's role as a valuable adjunct to routine cleaning. Conclusions: In conclusion, this study highlights that dry fogging effectively reduces microbial loads in open, high-traffic healthcare environments, supporting its use as part of a multimodal infection control strategy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Sublimation behavior of AlN in nitrogen and argon at conditions used for high-temperature annealing.
- Author
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Peters, Lukas, Sergeev, Dmitry, Margenfeld, Christoph, Müller, Michael, and Waag, Andreas
- Subjects
- *
MASS spectrometry , *SAPPHIRES , *EPITAXY , *PARTIAL pressure , *ARGON , *SURFACE contamination - Abstract
High-temperature annealing (HTA) is one of the most promising techniques to produce high-quality, cost-efficient AlN templates for further epitaxial growth of AlGaN devices. Unfortunately, the yield of this process seems to be limited due to the restricting face-to-face configuration that is typically used, in which contaminations of the template surface can occur easily. A high yield is crucial for process transfer into industry. Indeed, templates that are annealed in open-face configuration suffer from surface degradation due to excessive AlN evaporation during the course of the annealing process. To highlight the physics that are restricting the open-face approach of the process, sublimation behavior of AlN at temperatures and atmospheres typically used in HTA processes has to be examined. In this study, we use the Knudsen effusion mass spectrometry technique to confirm the previously published results on equilibrium partial pressures of species above AlN. Based on the experimentally determined data and further AlN sublimation experiments, the apparent sublimation coefficient of AlN in N2 and Ar atmospheres at HTA process conditions can be derived. Despite N2 having a stabilizing effect on AlN during HTA, the still high decomposition rates of several hundred nanometers per hour can explain the excessive damage that is typically observed if AlN/sapphire templates are annealed in an open-face configuration. Finally, based on theoretical considerations, a strategy to reduce the sublimation of AlN during HTA in open-face configuration is suggested. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Investigation of SARS-CoV-2 Contamination of Indoor Air and Highly Touched Surfaces On-Campus Buildings
- Author
-
Nita Khanal, Lauren Roppolo Brazell, Md Ariful Islam Juel, Cynthia Gibas, Jessica Schlueter, and Mariya Munir
- Subjects
surface contamination ,aerosol transmission ,highly touched surfaces ,COVID-19 spread ,and RNA quantification ,Microbiology ,QR1-502 - Abstract
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spreads primarily through respiratory droplets, aerosols, and contaminated surfaces. While high-traffic locations like hospitals and airports have been studied extensively, detecting significant virus levels in aerosols and on environmental surfaces, campus settings remain underexplored. This study focused on two crowded buildings at the University of North Carolina at Charlotte (UNCC). From December 2021 to March 2022, we collected 16 indoor air samples and 201 samples from high-touch surfaces. During the sampling timeframe, 44.82% of surface samples from the Student Union and 28% from the University Recreational Center (UREC) tested positive for the presence of SARS-CoV-2 RNA. Median and average viral RNA copies per swab were higher in UREC (273 and 475) than in Student Union (92 and 269). However, all air samples tested negative. Surface positivity in these high-traffic campus locations was directly correlated with COVID-19 clinical cases in Mecklenburg County. The campus COVID-19 cases, driven by the Omicron wave, peaked a week before the peak detection of surface contamination. These findings underscore the importance of surface hygiene measures and highlight environmental conditions as potential contributors to COVID-19 spread on campuses.
- Published
- 2024
- Full Text
- View/download PDF
35. Prediction of olive tuberculosis through physicochemical characterisation of <italic>Pseudomonas savastanoi</italic> and surfaces of different olive tree parts.
- Author
-
Mitro, Soukaina, Zanane, Chorouk, Hakim, Taoufik, Mazigh, Doha, Lekchiri, Souad, El Louali, Mostafa, Latrache, Hassan, and Zahir, Hafida
- Subjects
- *
ELECTRON donors , *BACTERIAL adhesion , *SURFACE contamination , *CONTACT angle , *SUSTAINABLE agriculture , *OLIVE - Abstract
This study examined plant–microbe interactions and surface contamination of olive trees by
Pseudomonas savastanoi pv.savastanoi , the pathogen causing olive tuberculosis. Using XDLVO theory, we assessed the theoretical adhesion ofP. savastanoi B97 cells to the bark, upper, and lower leaf surfaces of four olive cultivars based on physicochemical properties. Contact angle measurements revealed that lower leaf surfaces were more hydrophobic than upper leaf and bark surfaces, with a stronger electron donor character observed on the latter two. Lower leaf surfaces were identified as the preferred site for bacterial adhesion because of higher hydrophobicity. Among the cultivars, Arbicuina DOC and Arbicuina were most susceptible to colonisation. Conversely, cultivars with lower hydrophobicity and stronger electron donor properties, such as Haouzia and Moroccan Picholine, demonstrated greater resistance. These findings suggest that evaluating these properties can inform disease control strategies, promoting sustainable agriculture through resistant cultivars or targeted management of vulnerable surfaces. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
36. Controlled synthesis of silver/silicon hybrid nanostructures enables enhanced photocatalytic CO2 reduction.
- Author
-
Chen, Huai, Deng, Xuebiao, Lin, Meiqi, Yuan, Huiqing, Lan, Ban, and Xiong, Yangyang
- Subjects
- *
PHOTOREDUCTION , *SURFACE contamination , *SILVER nanoparticles , *SURFACE recombination , *SURFACE charges - Abstract
Localized surface plasmon resonances in plasmonic nanoparticles enable effective photon harvesting and generate energetic electrons and holes. However, fast charge recombination and surface contamination due to reactant-involved synthesis can significantly hinder the activity. Herein, we report a facile, solution-processed synthesis of hybrid uncoated silver nanoparticles combined with silicon nanocrystals to address these issues. The resulting hybrid nanocolloid exhibits enhanced photocatalytic CO2 reduction, achieving 1552 μmol g−1 and 100% selectivity for CO production. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. On the Variation in Surface State of Nominally Identical Fused Silica Optics Surfaces.
- Author
-
Seeling, Sebastian, Köhler, Robert, Tasche, Daniel, and Gerhard, Christoph
- Subjects
- *
FUSED silica , *ATOMIC force microscopy , *PHOTOELECTRON spectroscopy , *REFRACTIVE index , *SURFACE contamination , *LASER-induced breakdown spectroscopy - Abstract
ABSTRACT A considerable number of different tools and operating materials are used in classical optics manufacturing. Moreover, further parameters such as environmental and process conditions contribute to material removal and surface smoothing in the course of production. A large potential variety of the final surface state of optics can thus be expected. Against this background, nominally identical fused silica optics surfaces purchased from different suppliers were investigated in the present work via x‐ray photoelectron spectroscopy, laser‐induced breakdown spectroscopy, infrared spectroscopy, ellipsometry, and atomic force microscopy. It is shown that the surfaces under consideration feature quite different types and degrees of contamination that can be attributed to the particularly used water and polishing agent. Moreover, slight differences in index of refraction and surface roughness were detected. The presented data thus confirm the expectation that the surface state of an optical component might depend on its origin. The findings are intended to sensitize users regarding such a potential impact, for example, when switching to other suppliers for bought‐in parts and outsourced precision optics items. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Comparing Isovac® to High-Volume Evacuation on Aerosols and Surface Contamination During Operative Dentistry in Children: A Randomized, Controlled Trial.
- Author
-
Dworkin, Sara D., Kotak, Nidhi, Manchanda, Mega, and Lee, Susan
- Subjects
- *
SURFACE contamination , *OPERATIVE dentistry , *BIOLOGICAL interfaces , *INFECTION control , *BIOLUMINESCENCE - Abstract
Purpose: To compare the efficacy of high-volume evacuation (HVE) with a standard tip to Isovac® in reducing contamination. The changes in biological contamination on surfaces with distance and direction from the mouth were also examined. Methods: Children aged four to 17 years requiring an aerosol-producing restorative procedure on at least two primary and/or permanent teeth were included. For part one, 60 patients (Frankl score three or four) were randomly treated using HVE or Isovac®. After seven minutes, the patient’s napkin and operator’s face mask were examined for contamination. For part two, samples were collected from 15 subjects at five locations at varying distances and directions from the mouth after 12 minutes. Surface contamination was quantified using ATP bioluminescence. Results: Isovac® significantly reduced surface contamination versus HVE but only close to the patient. Contamination decreased rapidly with distance and was not greater than the control 18 inches from the mouth horizontally. More contamination was directed vertically than horizontally. There was no increase in contamination with longer preparation time. Conclusions: Surface contamination falls rapidly with distance. Isovac® was only superior to standard high-volume evacuation close to the mouth, which may not be clinically important for providers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
39. Polyamidoxime and graphene oxide synergistically stabilized foam decontaminant for removal of radioactive surface contaminants.
- Author
-
Lei, Sijie, Lin, Xiaoyan, and Han, Qiang
- Subjects
- *
RADIOACTIVE contamination , *SURFACE contamination , *GRAPHENE oxide , *STAINLESS steel , *POLLUTANTS - Abstract
In this study, polyacrylonitrile was modified to polyamidoxime to enhance foam stabilization and decontamination rate. Polyamidoxime was combined with graphene oxide, 1 wt% of saponins, and 1 wt% of alkyl glycosides to formulate the PAO/GO foam decontaminant. The outcomes demonstrated resulted in the half-life of the foam extending from 32 to 308 min. The PAO/GO foam decontaminant displayed α-ray decontamination rates of 93.30%, 98.34%, and 99.81% on stainless steel, tile, and glass surfaces. Hence, the dual functional PAO/GO in stabilizing foam while enhancing decontamination rates underscores its potential for radioactive decontamination. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. An Assessment of Surface Contamination and Dermal Exposure to 5-Fluorouracil in Healthcare Settings by UPLC-MS/MS Using a New Atmospheric Pressure Ionization Source.
- Author
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Creta, Matteo, Verscheure, Eline, Tans, Birgit, Devriese, Herman, Devriendt, An, Devolder, David, Lebegge, Robin, Poels, Katrien, Godderis, Lode, Duca, Radu-Corneliu, and Vanoirbeek, Jeroen A. J.
- Subjects
LAMINAR flow ,ANTINEOPLASTIC agents ,ATMOSPHERIC ionization ,SURFACE contamination ,SAFETY gloves - Abstract
5-Fluorouracil (5-FU) is a well-known cytostatic drug, which is often used in cancer treatments. Yet, it is also a very dangerous compound for people who are occupationally exposed to it for a long time, such as pharmacy employees, nurses and cleaning staff. We aimed to improve and implement a LC-MS/MS method for 5-FU quantification on surface contamination samples collected with swabs in a pharmacy department and outpatient nursing station of a university hospital. To improve the existing methods to quantify 5-FU, we compared a LC-MS/MS method using the frequently applied electrospray ionization source (ESI) with a UniSpray ionization source (USI). To determine the contamination of 5-FU in a pharmacy department preparing 5-FU infusion bags, which are then given to patients in the outpatient nursing stations, we collected multiple surface swabs of the laminar flow cabinets and frequently touched objects, before the preparation and administration of 5-FU and afterwards. Furthermore, we sampled the protective gloves and the bare hands of employees of the pharmacy department, involved in the preparation of the infusion bags. Using the USI source, we were able to reach the lowest limit of quantification (LOQ). With this technique, we were able to detect 5-FU contamination on the laminar flow cabinets and frequently used objects in the pharmacy department and the outpatient nursing station in the very low ng/cm
2 range. This contamination was mostly higher after preparation or administration than before. While we also found 5-FU on the protective gloves, we almost found no 5-FU on the skin of the pharmacy technicians preparing the 5-FU infusion bags. In conclusion, our method was able to detect very low concentrations of 5-FU contamination, but the contamination we found is very unlikely to result in any issues for the personnel working in these areas. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
41. Mechanism of Wheel-Rail Adhesion Recovery During Large Sliding Processes Under Water Lubrication Condition.
- Author
-
Zhou, Jiajun, Tian, Chun, Ma, Tianhe, and Zhai, Gengwei
- Subjects
WATER temperature ,SURFACE contamination ,HEAT transfer ,BRAKE systems ,WATER testing ,ROLLING contact - Abstract
The challenge of low adhesion between the wheel and the rail constrains the advancement of train braking technologies, resulting in sliding during braking, increased braking distances, and even operational safety incidents. Low adhesion arises from the contamination of the rail surface by a third body, such as water or oil, significantly reducing adhesion. However, experimental studies have found that wheel-rail adhesion coefficient under water lubrication conditions possesses recovery capability. In scenarios characterized by low adhesion in water lubrication conditions, a secondary rise in adhesion occurs when substantial wheel-rail sliding is present. This paper focuses on numerically modeling the unique phenomenon of adhesion recovery during large-sliding processes under water lubrication conditions. Considering the notable differences in frictional heating during wheel sliding, as opposed to pure rolling conditions, we construct a wheel-rail contact model under mixed lubrication conditions that incorporates the solid–liquid coupled heat transfer effect. This model achieves stable solutions for the wheel-rail contact relationship and the temperature at the wheel-rail interface. The impacts of velocity, axle load, water temperature, and slide ratio on the adhesion recovery phenomenon are discussed, revealing the underlying mechanism of adhesion recovery during large sliding processes. Finally, brake adhesion tests under water lubrication conditions are conducted on a scaled test rig to validate the proposed theoretical model. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Microplastic pollution in the surface waters of the zuari river, goa, india.
- Author
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Kalangutkar, Niyati, Mhapsekar, Shritesh, M. M., Abhaykrishna, and Pednekar, Pradnesh
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ENERGY dispersive X-ray spectroscopy ,WATER pollution ,POLYETHYLENE terephthalate ,RIVER pollution ,SURFACE contamination ,PLASTIC marine debris - Abstract
Limited research has been conducted on microplastic (MP) contamination in the rivers of Goa. To address this gap, this study examines the levels of MP contamination in the surface water of the Zuari River, Goa. We investigate the abundance, characteristics (size, shape, colour, and polymer composition), and risk assessment of MPs. MPs were detected at all sampling stations in the Zuari River, with concentrations varying from 0.01 particles/L (S3) to 1.38 particles/L (S13). The average abundance of MPs in the water samples was 0.28 ± 0.35 particles/L. MPs were more common in the 0.3–1 mm size range (51.70%) than in the 1–5 mm range (48.30%). The most common MP shapes observed were fibers (37.88%) and fragments (29.66%). FTIR analysis confirmed the presence of polyethylene terephthalate, high-density polyethylene, polypropylene, and polyacrylamide carboxyl-modified MPs. The Pollution Load Index (PLI) showed an average value of 3.8, indicating significant contamination (PLI > 1). Scanning electron microscopy (SEM) revealed various degradation features such as pits, scratches, grooves, and cracks on the MPs surfaces, while energy dispersive X-ray spectroscopy (EDS) detected metals on the MP's surfaces. This study provides key insights into MP pollution in the Zuari River's surface water and lays the groundwork for future research and management strategies in the region. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Microplastic contamination in three environmental compartments of a coastal lagoon in the southern Gulf of Mexico.
- Author
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Sánchez-Campos, Mitzi, Ponce-Vélez, Guadalupe, Sanvicente-Añorve, Laura, and Alatorre-Mendieta, Miguel
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PLASTIC marine debris ,BIOSPHERE reserves ,MICROPLASTICS ,SURFACE contamination ,PROTECTED areas ,RAYON ,LAGOONS - Abstract
The Sontecomapan lagoon (Mexico) is a Ramsar site within the Los Tuxtlas Biosphere Reserve, facing the Gulf of Mexico. Although the site has a protected area status, it is vulnerable to microplastic contamination, whose long-term effects are uncertain. This study gives the first approach to the degree of contamination by microplastics in surface waters, zooplankton, and sediments in the lagoon. The samples in these three environmental compartments were collected in June 2018 and analyzed in the laboratory to extract and quantify the microplastics. The microplastics sampled were classified into fibers, fragments, and foams and identified as polyester, acrylic, and rayon, among others. In the surface waters, the mean concentration of microplastics was 7.5 ± 5.3 items/L, which is higher than the values registered in other protected coastal systems, perhaps because of differences in the methods used. Zooplankton, represented by copepods, luciferids, and chaetognaths, showed concentrations of 0.002 ± 0.005, 0.011 ± 0.011, and 0.019 ± 0.016 items/individual, respectively. These values were low compared to systems with high anthropic influence, and the differences between the three kinds of organisms were attributed to their feeding habits. In the sediments, the mean concentration was 8.5 ± 12.5 items/kg, lower than the values registered in sites of high human impact; the maximum value here found (43 items/kg) was recorded in the internal part of a lagoon arm of almost stagnant water. In general, the degree of contamination by microplastics in the lagoon was low; however, their presence indicates a potential risk to the biota. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Development of α-ray visualization survey meter in high gamma and neutron background environment.
- Author
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Tsubota, Youichi, Kobayashi, Kenji, Ishii, Tatsuya, Hirato, Misaki, Shioya, Satoshi, and Nakagawa, Takahiro
- Subjects
SURFACE contamination ,BACKGROUND radiation ,PHOTOMULTIPLIERS ,NEUTRONS ,DENSITY - Abstract
A survey meter was developed to reliably detect and visualize surface contamination of suits and objects by α-nuclides in high γ/n-rays background radiation environment. The survey meter features a semi-opaque ZnS:Ag scintillator mounted directly onto a multi-anode photomultiplier tube (MA-PMT) and amplification circuits, ensuring output gain equalization for all channels. α-ray events induce localized light emission in thin-film scintillators. By directly mounting the scintillator, diffusion of light before reaching the MA-PMT is suppressed, concentrating it in just a few channels, thereby facilitating discrimination from background radiation. This design also enables clear visualization of the shape of surface contamination. The prototyped survey meter is capable of responding up to 2.1 × 10
7 cpm, with no γ-ray response even in high-radiation environments exceeding 1 Sv/h. In actual environments with high background radiation, contamination of ~1/100th of the surface contamination density limit of 4 Bq/cm2 could be reliably detected. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
45. Microbial Contamination and Sterilization Methods in an Air Circulation-Type Geothermal Ventilation System.
- Author
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Kim, Hyuntae
- Subjects
ULTRAVIOLET lamps ,STERILIZATION (Disinfection) ,HEAT exchangers ,AIR flow ,SURFACE contamination ,RADIATION sterilization ,MICROBIAL contamination - Abstract
A simulated system was created to evaluate an air circulation-type geothermal ventilation system, focusing on measuring microbial contamination levels on the surface of the heat exchange unit. Additionally, this study examined sterilization methods using UV lamps on the surface of the heat exchanger. The fungal concentration on the surface of the heat exchanger showed a tendency to increase over time. Although direct comparison is challenging due to the varying concentrations of outdoor air fungi at different measurement times, the surface fungal concentration was highest at a minimum airflow rate of 150 m
3 /h compared to other conditions. However, since the adhesion of contaminants from outdoor air to the surface of the heat exchanger is influenced not only by airflow but also by outdoor temperature and relative humidity conditions, future research needs to consider these factors. According to the ATP measurement results, microbial contamination was evaluated as "slightly dirty" after 24 h and "dirty" after 48 h of operating the experimental apparatus. Therefore, it is advisable to clean the internal surfaces of the geothermal ventilation system every 1–2 days. The results of the sterilization experiments using UV lamps indicated that irradiation for approximately 30 min inactivated 94.5%-to-96.1% of microorganisms derived from outdoor air. However, since the sterilization dose varies depending on the type of microorganism, it is necessary to determine the optimal irradiation time based on the target microorganisms and the UV lamp's irradiation intensity. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
46. EVALUATION OF PEEL PLY EFFECTIVENESS IN CONTROLLING MOULD RELEASE AGENT CONTAMINATION OF EPOXY/CARBON FIBRE COMPOSITE LAMINATE SURFACES.
- Author
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KUPPUSAMY, R. R. P., ZADE, A., and BABU, B. SRIDHAR
- Subjects
- *
LAMINATED materials , *X-ray photoelectron spectroscopy , *FIBROUS composites , *SURFACE contamination , *CARBON composites , *POLYESTERS - Abstract
The peel-ply effectiveness in controlling the mould release contaminations of resin transfer molded (RTM) RTM6/G0926 epoxy-carbon fibre composite laminate surfaces have been examined. X-ray photoelectron spectroscopy (XPS) was employed to evaluate the extent of transfer of mould release agents and other surface contaminants of RTM composite laminates at semi-cured and fully cured states. Fully cured and 55% semi-cure degree of RTM composite laminates were prepared using polyester and diatex peel plies. The effectiveness of polyester and diatex peel plies were evaluated by comparing the amount of Frekote mould release contaminants present in the laminate surfaces processed with and without peel plies. The XPS results shows that the composite laminates processed without peel plies at different cured states exhibit uniform contamination with Freakote calcium metal ions. At the comparisons of polyester and diatex peel plies, the diatex peel ply performs better in controlling the surface contaminations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Longitudinal evaluation of environmental contamination with hazardous drugs by surface wipe sampling.
- Author
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Sessink, Paul JM, Tans, Birgit, Spriet, Isabel, and Devolder, David
- Subjects
- *
ANALYSIS of hazardous substances , *DRUG adulteration , *RESEARCH funding , *LIQUID chromatography-mass spectrometry , *ENVIRONMENTAL monitoring , *HOSPITALS , *DESCRIPTIVE statistics , *STERILIZATION (Disinfection) , *LONGITUDINAL method , *POLLUTION , *OCCUPATIONAL exposure , *DOXORUBICIN , *GEMCITABINE , *DOSAGE forms of drugs , *HOSPITAL pharmacies , *CYCLOPHOSPHAMIDE - Abstract
Introduction: Exposure of healthcare workers to hazardous drugs can lead to adverse health effects supporting the importance of a continuous monitoring program, for example, by taking surface wipe samples. The objective was to describe the results of repeated monitoring of contamination with hazardous drugs on multiple surfaces in a hospital pharmacy and at two wards using standardized preparation techniques and cleaning procedures. Methods: Twelve surfaces in the hospital pharmacy and at two wards were sampled and analyzed for contamination with the hazardous drugs cyclophosphamide, doxorubicin, 5-fluorouracil, gemcitabine, methotrexate, and paclitaxel. The drugs were prepared with a closed-system drug transfer device (CSTD). Sampling of the drugs was performed in four trials during eight months. Liquid chromatography tandem mass spectrometry was used for the analysis of the drugs. Results: During the four trials, contamination with five of the six hazardous drugs was found on half of the surfaces in the pharmacy and in a ward. Seventeen out of 288 possible outcomes were positive (6%), with the biological safety cabinet grate (n = 6) and scanner (n = 5) most frequently contaminated. The highest level of contamination was observed on the pass-thru window (cyclophosphamide: 2.90 ng/cm2) and the touch screen of the Diana device (5-fluorouracil: 2.38 ng/cm2). Both levels were below the action level of 10 ng/cm2. Conclusions: The long-term use of a CSTD in combination with appropriate cleaning has proven effective in achieving low levels of surface contamination with hazardous drugs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Assessment of Surface Sterilisation Approaches for the Removal of Pollen DNA from Philaenus spumarius.
- Author
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McGreig, Sam, Pufal, Hollie, Conyers, Chris, Jones, Eleanor P., and Haynes, Edward
- Subjects
- *
PLANT DNA , *SURFACE contamination , *ULTRAVIOLET radiation , *INSECT-plant relationships , *POLLEN - Abstract
Simple Summary: To reliably identify the gut contents of plant-feeding insects, the removal of contaminant plant DNA from the insect surface is necessary. Previous approaches have used bleach and alcohol washes to achieve this. We perform a controlled baseline study on a herbivorous insect, the Meadow Spittlebug (Philaenus spumarius), to identify possible contamination that may persist after bleach washes. Despite the reported success of these methods, we find that contamination is still present, leading to unreliable results. We hypothesise that pollen is the main source of contamination, its robust nature making it difficult to remove. We conduct a further three experiments, investigating the effectiveness of more robust bleach washes, sterilised gut excision, and ultraviolet light as alternative sterilisation approaches. Overall, our findings indicate that we are unable to remove surface contamination while still detecting signals that may originate in the gut. In no experiment did we unequivocally detect plant DNA that originated in the P. spumarius gut. Dietary analysis of herbivorous insects relies on successfully eliminating surface contamination. If this cannot be performed reliably, then it will not be possible to differentiate between plants that the insect is feeding on and plants the insect has been in contact with, either directly or via pollen. Methods in the literature often use bleach and alcohol washes to remove contamination. We perform a controlled metabarcoding baseline study on a herbivorous, xylem-feeding insect, the Meadow Spittlebug (Philaenus spumarius), using Oxford Nanopore Technologies (ONT) sequencing, and identify possible contamination that persists after washes. Despite the reported success of methods in the literature, we find that contamination is still present, leading to possible false-positive results. We hypothesise that pollen is the main source of contamination, its robust nature making it difficult to remove, and conduct a further three experiments with the goal of removing pollen from the surface of Philaenus spumarius. This study investigates the effectiveness of robust bleach/Tween/alcohol washes, sterile gut excision (including combined with Distel application), and ultraviolet light as alternative sterilisation approaches. Overall, our findings indicate that we are unable to remove surface contamination and still detect signals that may originate in the gut. In no experiment did we unequivocally detect plant DNA that originated in the P. spumarius gut. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Results of Monitoring the Radioactive Contamination of Surface Water Bodies in the Surveillance Zone of the Mayak Production Association in 2023.
- Author
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Mokrov, Yu. G., Golubtsova, I. V., and Kochegorov, V. M.
- Subjects
- *
RADIOACTIVE contamination , *WATER pollution , *SURFACE contamination , *BODIES of water , *STRONTIUM isotopes - Abstract
A brief hydrographic description of the Techa River and main radionuclide-contaminated water bodies (WBs) located in the surveillance zone of the Mayak Production Association is made. Along with the Mayak Production Association, two other independent institutions monitor the radioactive contamination of these WBs. The results of monitoring the contamination of surface WBs, obtained by all the participating institutions in 2023, are presented in comparison with the results obtained in 2021–2022. With respect to the majority of the parameters monitored, the radioactive contamination of WBs is considerably lower than the interference level. In 2023, the discharge of radionuclides (90Sr) into the open hydrographic network of the Techa River was 0.24% of the established limit of permissible discharges. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Decontamination of Fused-Silica Surfaces by UVC Irradiation as Potential Application on Touchscreens.
- Author
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Sicks, Ben, Gurow, Oksana, Sommerfeld, Florian, and Hessling, Martin
- Subjects
MICROCOCCUS luteus ,SURFACE contamination ,QUARTZ crystals ,PSEUDOMONAS stutzeri ,ACINETOBACTER - Abstract
The contamination of surfaces by antibiotic-resistant pathogens presents an escalating challenge, especially on touchscreens in public settings such as hospitals, airports, and means of transport. Traditional chemical cleaning agents are often ineffective and leave behind harmful residues. Thus, the application of optical radiation is gaining relevance as a rapid, effective, and environmentally friendly disinfection method. This study examines the contamination of publicly accessible touchscreens and the efficacy of an irradiation approach for the radiation disinfection of microorganisms on quartz surfaces with UVC LEDs. In this setup, the LED radiation is laterally coupled into a quartz plate that serves as cover glass of a simplified touchscreen model. The process allows for the irradiation of microorganisms on the surface, without the user being exposed to hazardous radiation. To assess the efficacy of the disinfection process, a range of bacteria, mostly ESKAPE surrogates, such as Staphylococcus carnosus, Acinetobacter kookii, Escherichia coli, Enterococcus mundtii, and additionally Micrococcus luteus, were spread over a quartz plate with a homebuilt nebulization system. After operating the side-mounted LEDs for 30 s, a reduction in all bacteria except M. luteus by more than three orders of magnitude was observed. In the case of M. luteus, a significant reduction was achieved after 60 s (p < 0.05). This result demonstrates the potential of side-mounted UVC LEDs for rapid disinfection of touchscreens between two users and thus for reducing the spread of pathogens without irradiating humans. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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