Adherencia de bacterias a superficies recubiertas con grafeno

La adherencia de microorganismos sobre diferentes materiales y del desarrollo de "biofilms" generan problemas de biocorrosión y biodeterioro de materiales, afectando el normal funcionamiento de sistemas de distribución de agua, equipamiento industrial o dispositivos biomédicos, entre otros.Diferentes técnicas se han aplicado con el objeto de evitar o disminuir el desarrollo de "biofilms", tales como la modificación de las propiedades de superficies, la incorporación de nanoparticulas y/o biocidas en recubrimientos o desarrollo de nuevos recubrimientos. Entre este ultimo se encuentra el Grafeno (G), primer material 2D aislado y caracterizado que exhibe propiedades físico-químicas inusuales y únicos, en comparación a su contraparte el grafito. Desde su descubrimiento la comunidad científica esta trabajando en su aplicación en el diseño de materiales para sensado químico-biológico, catálisis por mencionar solo algunas.Centro de Investigación y Desarrollo en Tecnología de PinturasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Aplicación de grafeno en recubrimientos antifouling

La adherencia de microorganismos sobre diferentes materiales y el desarrollo de “biofilms” generan problemas de biocorrosión, pérdida de rendimiento de equipos, biodeterioro de materiales, etc. Puede afectar el normal funcionamiento de sistemas como tuberías de distribución de agua, equipamiento industrial o dispositivos biomédicos. Dado que la adherencia microbiana es requisito para que se genere el biofilm, tiene un importante impacto evitar, o al menos reducir, la contaminación biológica del sistema. Algunos enfoques eficaces para reducir esta problemática son: i) alterar las propiedades de la superficie de los materiales base de modo que sean menos afines con los microorganismos, ii) incorporar nanopartículas, y/o biocidas de origen natural en recubrimientos, iii) desarrollar nuevos recubrimientos con grafeno, entre otros. El grafeno (G) fue el primer material 2D aislado y caracterizado. Este nanocarbón exhibe propiedades químicas y físicas inusuales y únicas, en comparación a su contraparte el grafito. Desde su descubrimiento la comunidad científica esta trabajando en su aplicación en el diseño de materiales para sensado químico/biológico, catálisis, por mencionar sólo algunas. Pero poco se ha explorado sobre los efectos antimicrobianos que posee el G sobre bacterias formadoras de biofilms en materiales de importancia industrial y patrimonial. El objetivo de este trabajo fue determinar el efecto del G en la adherencia bacteriana y formación de biofilms sobre acero al carbono SAE 1010 y vidrio. La cubierta de G fue obtenida por la técnica CVD (chemical vapor deposition). La adherencia bacteriana y la formación del biofilm se ensayaron utilizando Pseudomonas sp. y Desulfovibrio. La inhibición de la adherencia bacteriana sobre los materiales cubiertos con G se analizó utilizando microscopia electrónica de barrido (MEB). Pudo observarse que en el acero al carbono SAE 1010, la película de G disminuyó la adherencia de ambas cepas bacterianas a la superficie metálica, no observándose este comportamiento sobre el vidrio.Adherence of microorganisms to surface of different materials and the subsequent development of biofilms generate several problems including biocorrosion, loss of equipment performance, deterioration of products, biodeterioration of materials, etc. Microbial adherence may affect the normal functioning of different systems including water distribution pipes, industrial equipment or biomedical devices. Given that adherence of microorganisms to surfaces is required for biofilm formation, preventing microbial adhesion is of major importance to avoid or at least reduce biological contamination of the system. Efficient proposals to solve this problem include: i) to alter the surface properties of the base materials, ii) to incorporate nanoparticles, and/or biocides of natural origin to coatings, iii) to develop new coatings using graphene, among other. Graphene (G) was the first 2D material to be isolated and characterized. This nanocarbon shows unusual and unique chemical and physical properties compared with its counterpart, the graphite. Since the discovery of graphene the scientific community has been actively working on the application of this nanocarbon in the design of materials for chemical/biological sensing, to name a few. However, there has been little discussion on the antimicrobial effects of G on bacteria forming biofilms in materials of industrial and patrimonial importance The aim of this study was to determine the effect of G coating in bacterial adherence and biofilms formations on 1010 carbon steel and on glass. G was obtained by the CVD technique (chemical vapor deposition). Bacterial adherence and biofilm formation were tested using two bacteria Pseudomonas sp. and Desulfovibrio vulgaris. Inhibition of bacterial adherence on materials covered with G was analyzed using scanning electronic microscopy (SEM). Results from the analysis revealed that the G film caused a reduction on the adherence of both bacteria to the steel surface. No reduction in the adherence on glass samples was observed.Centro de Investigación y Desarrollo en Tecnología de PinturasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Aplicación de grafeno en recubrimientos antifouling

La adherencia de microorganismos sobre diferentes materiales y el desarrollo de “biofilms” generan problemas de biocorrosión, pérdida de rendimiento de equipos, biodeterioro de materiales, etc. Puede afectar el normal funcionamiento de sistemas como tuberías de distribución de agua, equipamiento industrial o dispositivos biomédicos. Dado que la adherencia microbiana es requisito para que se genere el biofilm, tiene un importante impacto evitar, o al menos reducir, la contaminación biológica del sistema. Algunos enfoques eficaces para reducir esta problemática son: i) alterar las propiedades de la superficie de los materiales base de modo que sean menos afines con los microorganismos, ii) incorporar nanopartículas, y/o biocidas de origen natural en recubrimientos, iii) desarrollar nuevos recubrimientos con grafeno, entre otros. El grafeno (G) fue el primer material 2D aislado y caracterizado. Este nanocarbón exhibe propiedades químicas y físicas inusuales y únicas, en comparación a su contraparte el grafito. Desde su descubrimiento la comunidad científica esta trabajando en su aplicación en el diseño de materiales para sensado químico/biológico, catálisis, por mencionar sólo algunas. Pero poco se ha explorado sobre los efectos antimicrobianos que posee el G sobre bacterias formadoras de biofilms en materiales de importancia industrial y patrimonial. El objetivo de este trabajo fue determinar el efecto del G en la adherencia bacteriana y formación de biofilms sobre acero al carbono SAE 1010 y vidrio. La cubierta de G fue obtenida por la técnica CVD (chemical vapor deposition). La adherencia bacteriana y la formación del biofilm se ensayaron utilizando Pseudomonas sp. y Desulfovibrio. La inhibición de la adherencia bacteriana sobre los materiales cubiertos con G se analizó utilizando microscopia electrónica de barrido (MEB). Pudo observarse que en el acero al carbono SAE 1010, la película de G disminuyó la adherencia de ambas cepas bacterianas a la superficie metálica, no observándose este comportamiento sobre el vidrio.Adherence of microorganisms to surface of different materials and the subsequent development of biofilms generate several problems including biocorrosion, loss of equipment performance, deterioration of products, biodeterioration of materials, etc. Microbial adherence may affect the normal functioning of different systems including water distribution pipes, industrial equipment or biomedical devices. Given that adherence of microorganisms to surfaces is required for biofilm formation, preventing microbial adhesion is of major importance to avoid or at least reduce biological contamination of the system. Efficient proposals to solve this problem include: i) to alter the surface properties of the base materials, ii) to incorporate nanoparticles, and/or biocides of natural origin to coatings, iii) to develop new coatings using graphene, among other. Graphene (G) was the first 2D material to be isolated and characterized. This nanocarbon shows unusual and unique chemical and physical properties compared with its counterpart, the graphite. Since the discovery of graphene the scientific community has been actively working on the application of this nanocarbon in the design of materials for chemical/biological sensing, to name a few. However, there has been little discussion on the antimicrobial effects of G on bacteria forming biofilms in materials of industrial and patrimonial importance The aim of this study was to determine the effect of G coating in bacterial adherence and biofilms formations on 1010 carbon steel and on glass. G was obtained by the CVD technique (chemical vapor deposition). Bacterial adherence and biofilm formation were tested using two bacteria Pseudomonas sp. and Desulfovibrio vulgaris. Inhibition of bacterial adherence on materials covered with G was analyzed using scanning electronic microscopy (SEM). Results from the analysis revealed that the G film caused a reduction on the adherence of both bacteria to the steel surface. No reduction in the adherence on glass samples was observed.Centro de Investigación y Desarrollo en Tecnología de PinturasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Adherencia de bacterias a superficies recubiertas con grafeno

La adherencia de microorganismos sobre diferentes materiales y del desarrollo de "biofilms" generan problemas de biocorrosión y biodeterioro de materiales, afectando el normal funcionamiento de sistemas de distribución de agua, equipamiento industrial o dispositivos biomédicos, entre otros.Diferentes técnicas se han aplicado con el objeto de evitar o disminuir el desarrollo de "biofilms", tales como la modificación de las propiedades de superficies, la incorporación de nanoparticulas y/o biocidas en recubrimientos o desarrollo de nuevos recubrimientos. Entre este ultimo se encuentra el Grafeno (G), primer material 2D aislado y caracterizado que exhibe propiedades físico-químicas inusuales y únicos, en comparación a su contraparte el grafito. Desde su descubrimiento la comunidad científica esta trabajando en su aplicación en el diseño de materiales para sensado químico-biológico, catálisis por mencionar solo algunas.Centro de Investigación y Desarrollo en Tecnología de PinturasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Aplicación de grafeno en recubrimientos antifouling

La adherencia de microorganismos sobre diferentes materiales y el desarrollo de “biofilms” generan problemas de biocorrosión, pérdida de rendimiento de equipos, biodeterioro de materiales, etc. Puede afectar el normal funcionamiento de sistemas como tuberías de distribución de agua, equipamiento industrial o dispositivos biomédicos. Dado que la adherencia microbiana es requisito para que se genere el biofilm, tiene un importante impacto evitar, o al menos reducir, la contaminación biológica del sistema. Algunos enfoques eficaces para reducir esta problemática son: i) alterar las propiedades de la superficie de los materiales base de modo que sean menos afines con los microorganismos, ii) incorporar nanopartículas, y/o biocidas de origen natural en recubrimientos, iii) desarrollar nuevos recubrimientos con grafeno, entre otros. El grafeno (G) fue el primer material 2D aislado y caracterizado. Este nanocarbón exhibe propiedades químicas y físicas inusuales y únicas, en comparación a su contraparte el grafito. Desde su descubrimiento la comunidad científica esta trabajando en su aplicación en el diseño de materiales para sensado químico/biológico, catálisis, por mencionar sólo algunas. Pero poco se ha explorado sobre los efectos antimicrobianos que posee el G sobre bacterias formadoras de biofilms en materiales de importancia industrial y patrimonial. El objetivo de este trabajo fue determinar el efecto del G en la adherencia bacteriana y formación de biofilms sobre acero al carbono SAE 1010 y vidrio. La cubierta de G fue obtenida por la técnica CVD (chemical vapor deposition). La adherencia bacteriana y la formación del biofilm se ensayaron utilizando Pseudomonas sp. y Desulfovibrio. La inhibición de la adherencia bacteriana sobre los materiales cubiertos con G se analizó utilizando microscopia electrónica de barrido (MEB). Pudo observarse que en el acero al carbono SAE 1010, la película de G disminuyó la adherencia de ambas cepas bacterianas a la superficie metálica, no observándose este comportamiento sobre el vidrio.Adherence of microorganisms to surface of different materials and the subsequent development of biofilms generate several problems including biocorrosion, loss of equipment performance, deterioration of products, biodeterioration of materials, etc. Microbial adherence may affect the normal functioning of different systems including water distribution pipes, industrial equipment or biomedical devices. Given that adherence of microorganisms to surfaces is required for biofilm formation, preventing microbial adhesion is of major importance to avoid or at least reduce biological contamination of the system. Efficient proposals to solve this problem include: i) to alter the surface properties of the base materials, ii) to incorporate nanoparticles, and/or biocides of natural origin to coatings, iii) to develop new coatings using graphene, among other. Graphene (G) was the first 2D material to be isolated and characterized. This nanocarbon shows unusual and unique chemical and physical properties compared with its counterpart, the graphite. Since the discovery of graphene the scientific community has been actively working on the application of this nanocarbon in the design of materials for chemical/biological sensing, to name a few. However, there has been little discussion on the antimicrobial effects of G on bacteria forming biofilms in materials of industrial and patrimonial importance The aim of this study was to determine the effect of G coating in bacterial adherence and biofilms formations on 1010 carbon steel and on glass. G was obtained by the CVD technique (chemical vapor deposition). Bacterial adherence and biofilm formation were tested using two bacteria Pseudomonas sp. and Desulfovibrio vulgaris. Inhibition of bacterial adherence on materials covered with G was analyzed using scanning electronic microscopy (SEM). Results from the analysis revealed that the G film caused a reduction on the adherence of both bacteria to the steel surface. No reduction in the adherence on glass samples was observed.Centro de Investigación y Desarrollo en Tecnología de PinturasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Speculative Trading and Market Performance: The Effect of Arbitrageurs on Efficiency and Market Power in the New York Electricity Market

While the effect speculators have on forward premiums (the difference between forward and expected spot prices) has been widely studied, there has been very little focus on the effect speculators have on competition in the product market. I study the effect speculators have had on production decisions and price levels in New York’s deregulated electricity market. For the first two years of its operation, the market, which opened in November 1999, restricted trade to producers and retailers of electricity. During this period, the forward price of electricity in western New York was significantly higher than the expected spot price. I show that, after the market opened to purely speculative traders, the forward premium significantly decreased. In addition, the forward price of transmission (the price difference between two geographically distinct points) ceased to differ significantly from the expected spot price of transmission. I present a theoretical model to help understand these price relationships and other possible effects of speculators on market prices and firms’ production decisions. Absent speculators, the model predicts that firms with market power will price discriminate between the forward and spot markets for electricity, resultin

An Empirical Assessment of the Competitiveness of the New England Electricity Market

Underlying the current debates over the appropriate organization of the electricity industry and its wholesale markets is a need for metrics that allow for comparisons of the markets that are already operating. One such metric is provided by competitive benchmark analysis. The basic idea behind a competitive benchmark is to estimate the price that would result if no firm attempted to exercise market power and to compare it to observed market prices. In this paper we estimate competitive benchmark prices for the electricity market overseen by the Independent System Operator of New England (ISO-NE).We study the period from May 1999 to September 2001. Using the Energy Clearing Price (ECP) of the ISO-NE as a measure of market price, we find the demand-weighted markup between the ECP and the competitive benchmark to be 12%. However, the ECP reflects adjustments for factors, including transmission congestion and other unit operating constraints, that are not explicitly considered in forming our competitive benchmark. Alternative measures of market prices that more closely match our methods for estimating a competitive price can be derived by intersecting market demand with the aggregate supply curve taken from the offer prices of generation units. One such measure intersects the aggregate offer curve of all generation units with overall market demand. Using this measure of price, we find a demand-weighted markup of 4% over our estimate of competitive price.Another measure of price intersects the offer prices only of large fossil-fuel generation units with the actual demand served by that set of units. This price is usually higher than the previous offer-based measure because transmission and other operating constraints cause many fossil-fuel units to be called upon to operate even though their offer prices are higher than other units that are not operating. The margin produced from this latter offer-based measure is 11%. However this latter margin does not reflect ISO-NE's ex-post reduction of offer prices from certain transmission constrained units. Because of these reductions, the revenues earned by these units will be lower than indicated by this measure. It is extremely difficult to say how large the impact of ex-post market-power mitigation on this index is without more detailed data on specific mitigation events.The differences among these three measures indicate that factors other than energy bids play an important role in market outcomes in New England. Unit operating constraints are raising the ECP above the levels produced by a simple aggregation of energy bids. In addition, the set of units actually called upon to operate appears to be working larger margins into their energy offer prices than are reflected in the bids of other units. It is likely that the strategic bidding of other unit operating parameters, such Low Operating Limits (LOL) also plays a role in these outcomes.Other studies using similar methods have examined the competitive performance of the California and PJM electricity markets. The only time period over which all 3 studies overlap is May to December 1999. Over this period the performance of the New England market compares favorably to that of the California and PJM electricity markets. Further comparison of the New England and California markets during 2000 reinforces this impression.From the perspective of market efficiency the results to date are encouraging, particularly when compared to California, but need to be considered in context. The continued vertical integration of some suppliers and the transition contracts imposed on others provide a powerful mitigating influence on the incentives of these firms to exercise market power. The pending expiration of transition periods and potential consolidation of supply portfolios will reverse this effect. It is difficult to predict the extent to which new entry will offset these trends. The market power created by transmission congestion and other unit operating constraints presents an ongoing challenge to the efficient operation of electricity markets. Last, the operations, monitoring, and market power mitigation functions of the ISO no doubt has contributed to the outcomes detailed in this report. It is important that we continue to examine both the short and long term impacts of these activities, particularly as widespread changes to the ISO-NE's operations and pricing protocols are adopted

Market structure and competition: a cross-market analysis of U.S. electricity deregulation, CSEM Working Paper No

This paper examines the importance of market characteristics in restructured electricity markets. We measure market performance relative to benchmarks that abstract away from market design characteristics but capture important structural elements. Specifically, we estimate market outcomes under an assumption of perfect competition and under an assumption of Cournot competition in three U.S. markets: California, New England, and PJM. These two counter-factual assumptions bound the space of possible static, non-cooperative outcomes. By establishing where actual market outcomes fall within these bounds, we can compare how markets perform relative to the extremes determined by structural factors alone. Our findings suggest that vertical arrangements between suppliers and retailers, dramatically affect estimated market outcomes. When we include vertical arrangements in firms ’ objective functions, Cournot equilibrium prices in both PJM and New England fall dramatically. California did not have such arrangements. After accounting for vertical arrangements, performance in each market relative to Cournot is similar, particularly during hours of peak demand