Role Of Surface Contamination Research Articles

One-year monitoring SARS-CoV-2 RNA surface contamination in hospitals reveals no correlation with organic material and negative pressure as a limiting factor for contamination

Understanding transmission routes of SARS-CoV-2 is crucial to establish effective interventions in healthcare institutions. Although the role of surface contamination in SARS-CoV-2 transmission has been controversial, fomites have been proposed as a contributing factor. Longitudinal studies about SARS-CoV-2 surface contamination in hospitals with different infrastructure (presence or absence of negative pressure systems) are needed to improve our understanding of their effectiveness on patient healthcare and to advance our knowledge about the viral spread.We performed a one-year longitudinal study to evaluate surface contamination with SARS-CoV-2 RNA in reference hospitals. These hospitals have to admit all COVID-19 patients from public health services that require hospitalization. Surfaces samples were molecular tested for SARS-CoV-2 RNA presence considering three factors: the dirtiness by measuring organic material, the circulation of a high transmissibility variant, and the presence or absence of negative pressure systems in hospitalized patients' rooms.Our results show that: (i) There is no correlation between the amount of organic material dirtiness and SARS-CoV-2 RNA detected on surfaces; (ii) SARS-CoV-2 high transmissible Gamma variant introduction significantly increased surface contamination; (iii) the hospital with negative pressure systems was associated with lower levels of SARS-CoV-2 surface contamination and, iv) most environmental samples recovered from contaminated surfaces were assigned as non-infectious.This study provides data gathered for one year about the surface contamination with SARS-CoV-2 RNA sampling hospital settings. Our results suggest that spatial dynamics of SARS-CoV-2 RNA contamination varies according with the type of SARS-CoV-2 genetic variant and the presence of negative pressure systems. In addition, we showed that there is no correlation between the amount of organic material dirtiness and the quantity of viral RNA detected in hospital settings. Our findings suggest that SARS CoV-2 RNA surface contamination monitoring might be useful for the understanding of SARS-CoV-2 dissemination with impact on hospital management and public health policies. This is of special relevance for the Latin-American region where ICU rooms with negative pressure are insufficient.

Analysis of acute sinusitis-related early failed implant surface: a combined histological, electron microscopy, and X-ray spectroscopy approach

BackgroundEven though dental implants are a reliable choice for dental rehabilitation, implant failures due to various etiologies have been reported. Early implant failures account for 2 to 6% of installed implants and are reported to have a higher rate than late failures, regardless of loading time. We herein report three cases of acute sinusitis and early implant failure with implants that failed within 1 month after installation. The aim of this study was to evaluate the surface properties of early failed implants and peri-implant tissue to determine the early osseointegration pattern in acute sinusitis-related failed implants as well as the possible role of surface contamination in the failure of osseointegration.ResultsA combined histological, electron microscopy, and X-ray spectroscopy approach was used to characterize the surface of non-osseointegrated titanium implants and the surrounding biological tissues. Morphologic scanning electron microscopy revealed a heterogeneous surface and irregular osseointegration. The implant surface was covered mostly by carbon- and oxygen-rich organic matter. Energy-dispersive X-ray spectroscopy surface analysis of three implants showed the incorporation of some contaminants in both the upper and apical regions. Carbon, nitrogen, sodium, silicon, chlorine, sulfur, gold, and zirconium were detected on the surface of one or more failed implants. Fibrosis, lymphocytic, and macrophage infiltrates and a high activation of osteoclasts surrounding the bone graft particles were detected in the surrounding tissues.ConclusionsThe etiology and mechanism of early implant failure, especially in sinus-related cases, as well as the proper management interventions to minimize the rate of early implant failures, are of great concern. No matter how confident and accurate the surgeon’s operation, there may be unknown errors in the whole procedure that no one knows about. Rather than errors related to the implant surface, it is expected that there were invisible problems during the evaluation of the patient’s own unique sinus mucosal inflammation or the operator’s own procedure. Furthermore, well-designed researches are necessary to reveal the effect of material-related factors on acute sinus complication and early implant failure.

Collective bursting of free-surface bubbles, and the role of surface contamination

Abstract

Nanodiamond seeding on plasma-treated tantalum thin films and the role of surface contamination

The surface of tantalum (Ta) thin films is exposed to different gas discharge plasmas (N2, O2, CF4) followed by an investigation of surface wetting properties and water-based colloidal seeding of ultra-dispersed nanodiamond (ND) particles. Fluorination of the Ta surface resulted in a hydrophobic surface, whereas other surface treatments resulted in hydrophilic surfaces. Regardless of treatment and wetting contact angle, the ND seeding density of approximately 2 × 1011cm−2 is obtained for all the samples. This shows that the electrostatic interaction of the Ta surface with ND particles is the primary factor determining the successful ND seeding, while the surface wetting property is of lesser importance. In addition, Ta surface contamination dynamics and its impact on ND seeding is studied. An analytic model is proposed to account for surface contamination and explain its impact on the ND seeding density. The model can be more generally applied for other material systems.

Application of a Continuously Active Antimicrobial Surface Coating in Two Professional Sports Training Facilities

Background: The role of surface contamination in infections is of interest in healthcare as well as other industries, especially where infections incur high cost. One such industry is professional sports, where infections pose significant risks to players and the organizations that employ them. Sports training facilities experience highly variable occupancy rates due to differing seasonal activities, presenting a measurement challenge because the relationship between occupancy and surface contamination is not well described. In a recent publication, a continuously active antimicrobial (CAA) surface coating demonstrated a reduction in bacterial bioburden in ICUs alongside a reduction in healthcare-associated infections (HAIs). Objective: We investigated the impact of a CAA surface coating on bioburden in 2 professional sports training facilities, despite changes in occupancy. Methods: A CAA surface coating was applied using an electrostatic sprayer to all surfaces in both facilities during a period of high-occupancy at facility A and during low occupancy at facility B. Surface cultures were taken using 3M Sponge-Sticks from lockers, gym equipment, and physiotherapy surfaces before treatment, 4–13 weeks after treatment at facility A and 4–23 weeks after treatment at facility B. Total aerobic bacteria counts were obtained by plating on tryptic soy agar, and geometric means of aerobic plate counts (APCs) were used to compare bioburden before and after treatment at both facilities and for an out-of-efficacy period at facility B (17–23 weeks). Occupancy rates were monitored as person days per week (pd/w) over the course of the study. Results: APC counts at facility A decreased 61% (585 CFU/100 cm2 to 226 CFU/100 cm2) from baseline to posttreatment, and occupancy remained constant (165 pd/w to 171 pd/w). At facility B, there was no significant change in APC (76 CFU/100 cm2 to 80 CFU/100 cm2), although occupancy increased >13,000% during the treatment period (3 pd/w to 386 pd/w). During the out-of-efficacy period at facility B, total bacteria increased 170% (217 CFU/100 cm2) compared to the treatment period, and the occupancy remained relatively constant (344 pd/w). Conclusions: Levels of bioburden were significantly influenced by the application of the CAA surface coating, especially considering the variation in occupancy in both facilities before, during, and after the efficacy period. Facility A saw a significant reduction in bioburden during the treatment period (P < .0001), and a significant increase was observed at facility B during the out-of-efficacy period (P < .0001) despite constant occupancy rates, demonstrating the ability of the surface coating to reduce bioburden levels despite large changes in occupancy.Funding: Allied BioScience, Inc, provided Funding: for this study.Disclosures: Gavri Grossman, Valerie Beck, and Daniel S Watson report salary from Allied BioScience.

Role of Surface Contamination in Titanium PM

The powder metallurgy (PM) approach is widely used for cost-effective production of titanium alloys and articles. In the PM approach the large specific surface of starting powders heightens the risk of excessive impurity presence and, hence, degradation of final alloy properties. The present study analyzes the opportunity to produce sintered commercially pure titanium (CP-Ti) with acceptable impurity content from powder materials. Starting titanium and titanium hydride powders were comparatively examined. The impurity elements (oxygen, chlorine, carbon) and their conditions on the powder particle surface, as well as the surface processes and gases emitted from powders upon heating, have been analyzed by means of surface science techniques. The role of hydrogen emitted from titanium hydride in material purification has been discussed. The opportunity to produce titanium materials with final admissible content of interstitials (O, C, Cl, and H) using starting titanium hydride powder has been demonstrated.

Nanotribology and nanomechanics in nano/biotechnology

Owing to larger surface area in micro/nanoelectromechanical systems (MEMS/NEMS), surface forces such as adhesion, friction, and meniscus and viscous drag forces become large when compared with inertial and electromagnetic forces. There is a need to develop lubricants and identify lubrication methods that are suitable for MEMS/NEMS. For BioMEMS/BioNEMS, adhesion between biological molecular layers and the substrate, and friction and wear of biological layers may be important, and methods to enhance adhesion between biomolecules and the device surface need to be developed. There is a need for development of a fundamental understanding of adhesion, friction/stiction, wear, the role of surface contamination and environment, and lubrication. MEMS/NEMS materials need to exhibit good mechanical and tribological properties on the micro/nanoscale. Most mechanical properties are known to be scale dependent. Therefore, the properties of nanoscale structures need to be measured. Component-level studies are required to provide a better understanding of the tribological phenomena occurring in MEMS/NEMS. The emergence of micro/nanotribology and atomic force microscopy-based techniques has provided researchers with a viable approach to address these problems. This paper presents an overview of micro/nanoscale adhesion, friction, and wear studies of materials and lubrication studies for MEMS/NEMS and BioMEMS/BioNEMS. It also presents a review of scale-dependent mechanical properties, and stress and deformation analysis of nanostructures.

Nanotribology and nanomechanics of MEMS/NEMS and BioMEMS/BioNEMS materials and devices

The micro/nanoelectromechanical systems (MEMS/NEMS) need to be designed to perform expected functions typically in millisecond to picosecond range. Expected life of the devices for high speed contacts can vary from few hundred thousand to many billions of cycles, e.g., over a hundred billion cycles for digital micromirror devices (DMDs), which puts serious requirements on materials. For BioMEMS/BioNEMS, adhesion between biological molecular layers and the substrate, and friction and wear of biological layers may be important. There is a need for development of a fundamental understanding of adhesion, friction/stiction, wear, and the role of surface contamination, and environment. Most mechanical properties are known to be scale dependent. Therefore, the properties of nanoscale structures need to be measured. MEMS/NEMS materials need to exhibit good mechanical and tribological properties on the micro/nanoscale. There is a need to develop lubricants and identify lubrication methods that are suitable for MEMS/NEMS. Methods need to be developed to enhance adhesion between biomolecules and the device substrate. Component-level studies are required to provide a better understanding of the tribological phenomena occurring in MEMS/NEMS. The emergence of micro/nanotribology and atomic force microscopy-based techniques has provided researchers a viable approach to address these problems. This paper presents a review of micro/nanoscale adhesion, friction, and wear studies of materials and lubrication studies for MEMS/NEMS and BioMEMS/BioNEMS, and component-level studies of stiction phenomena in MEMS/NEMS devices.

Comparative thickness measurements of SiO2/Si films for thicknesses less than 10 nm

AbstractWe report on a comparative measurement of SiO2/Si dielectric film thickness (t < 10 nm) using grazing‐incidence x‐ray photoelectron spectroscopy, neutron reflectometry and spectroscopic ellipsometry. Samples with nominal thicknesses of 3–7 nm were characterized by XPS with grazing‐incidence x‐rays at 1.8 keV, by cold neutron reflectometry (λ = 0.475 nm) and by spectroscopic ellipsometry over 1.5 eV < E < 6.0 eV. The results show good agreement between the ellipsometry and grazing‐incidence XPS, with slightly lower values for the neutron reflectometry. The role of surface contamination in each type of measurement is discussed. Published in 2004 by John Wiley & Sons, Ltd.

Role of Environmental Contamination in the Transmission of Vancomycin-Resistant Enterococci

The acquisition and spread of bacterial resistance to commonly used antibiotics is an ongoing problem in the 1990s.1 Important nosocomial pathogens with an increasing incidence or newly acquired resistance include oxacillin-resistant Staphylococcus aureus, enteric gram-negative bacilli producing extended-spectrum p-lactamase, and vancomycin-resistant Enterococcus species (VRE). Reports of VRE began to appear in the mid-1980s in Europe and are now an important problem in an evergrowing number of hospitals in the United States. Data accumulated via the National Nosocomial Infection Surveillance (NNIS) system of the Centers for Disease Control and Prevention (CDC) revealed that VRE increased 35-fold among all nosocomial isolates of enterococci (0.3% to 10.4%) between 1989 and 1995.2 By 1994 and 1995, 41% of all NNIS hospitals reported at least one nosocomial enterococcal infection. A recent report notes that attributable mortality is approximately 40%.3 Because of the importance of VRE as a nosocomial pathogen, the Hospital Infection Control Practices Advisory Committee (HICPAC) of the CDC has published guidelines for preventing nosocomial transmission.4 Among the important scientific questions regarding nosocomially acquired VRE are the following. First, do patients colonized or infected with VRE contaminate their environment? Second, what is the role of surface contamination in the transmission of VRE? Third, is surface contamination linked to the transmission of other nosocomial pathogens? Finally, what scientifically based policies can infection control professionals adopt to prevent or reduce nosocomial transmission of these pathogens? Several investigators have studied the frequency of environmental contamination found in the rooms of patients with VRE.11 Cultures of the surface environment yielded VRE in 7% to 37% of samples (Table). These investigations also produced several other important findings. Boyce et al reported that environmental contamination was more widespread in the rooms of patients with diarrhea6 (Table). In a later study, Boyce et al reported that the disposable gowns of nurses who cared for a patient with copious diarrhea also were contaminated with VRE.8 Montecalvo et al reported that 8% of cultures taken after terminal cleaning still yielded VRE.7 Molecular analysis of VRE strains has demonstrated both multiple circulating strains9,1112 and outbreaks due to a single strain.6,8,12,13 In some cases, isolates obtained from the environment were identical to the epidemic strain causing infection.6'8 However, in these outbreaks, it often has been difficult to determine whether cross-transmission occurred due to contaminated common equipment (eg, stethoscopes), acquisition of transient hand carriage by

The diffusion coefficient of hydrogen and deuterium in vanadium, niobium and tantalum by Gorsky-effect measurements. (Germany): G Schaumann et al, Phys Stat Sol, 42 (1), Nov 1970, 401–413

An examination has been made of the prebreakdown conduction between stainless steel, copper, aluminium and tungsten electrodes at small gaps (less than 1 cm) and in poor (106 torr, unbaked) and clean (3 x 109 torr, baked) vacuum systems. Emphasis has been placed on means of distinguishing between the various types of conduction found to occur. These were identified as (1) field emission and an associated current pulse structure, (2) field emission and activationfignition effects, (3) microdischarges. This identification was possible directly as a result of using a fast response current measuring system. Equally, the determination of true field emission characteristics, especially in the poor vacuum system, in the presence of the pulse structure and activationlignition effects was achieved only by means of an ageing process and a fast I-V plotter. The role of surface contamination in determining apparent emission law characteristics has been recognized and a simple, qualitative model proposed which can account for many of the observed effects.

Prebreakdown conduction between vacuum insulated electrodes

An examination has been made of the prebreakdown conduction between stainless steel, copper, aluminium and tungsten electrodes at small gaps (less than 1 cm) and in poor (106 torr, unbaked) and clean (3 x 109 torr, baked) vacuum systems. Emphasis has been placed on means of distinguishing between the various types of conduction found to occur. These were identified as (1) field emission and an associated current pulse structure, (2) field emission and activationfignition effects, (3) microdischarges. This identification was possible directly as a result of using a fast response current measuring system. Equally, the determination of true field emission characteristics, especially in the poor vacuum system, in the presence of the pulse structure and activationlignition effects was achieved only by means of an ageing process and a fast I-V plotter. The role of surface contamination in determining apparent emission law characteristics has been recognized and a simple, qualitative model proposed which can account for many of the observed effects.