Combined Surface-Enhanced Raman and Infrared Absorption Spectroscopies for Streamlined Chemical Detection of Polycyclic Aromatic Hydrocarbon-Derived Compounds.

Polycyclic aromatic hydrocarbons (PAHs) constitute a class of universally prevalent carcinogenic environmental contaminants. It is increasingly recognized, however, that PAHs derivatized with oxygen, sulfur, or nitrogen functional groups are frequently more dangerous than their unfunctionalized counterparts. This much larger family of chemicals─polycyclic aromatic compounds─PACs─is far less well characterized than PAHs. Using surface-enhanced Raman and IR Absorption spectroscopies (SERS + SEIRA) combined on a single substrate, along with density functional theoretical (DFT) calculations, we show that direct chemical detection and identification of PACs at sub-parts-per-billion concentration can be achieved. Focusing our studies on 9,10-anthraquinone, 5,12-tetracenequinone, 9-nitroanthracene, and 1-nitropyrene as model PAC contaminants, detection is made possible by incorporating a hydroxy-functionalized self-assembled monolayer that facilitates hydrogen bonding between analytes and the SERS + SEIRA substrate. 5,12-Tetracenequinone was detected at 0.3 ppb, and the limit of detection was determined to be 0.1 ppb using SEIRA alone. This approach is straightforwardly extendable to other families of analytes and will ultimately facilitate fieldable chemical detection of these dangerous yet largely overlooked environmental contaminants.

Performance of modified first-stage French Vertical Flow Constructed Wetlands under extreme operational conditions.

Operation conditions considerably affect the removal efficiency of wastewater treatment systems, and yet we still lack data on how these systems function under extreme dilution rates and climatic conditions at high altitudes. Here, we applied two modified First-Stage French Vertical Flow Constructed Wetlands (FS-FVFCWs) for sewage treatment in Northern Tropical Andes. Specifically, within 18 months, we conducted a pilot-scale experiment at two hydraulic loading rates (HLRs) of 0.94 and 0.56 m d-1, representing 2.5 and 1.5 times the recommended design values, with two different feeding/resting periods to investigate the impact of HLRs and operational strategy on system performance. We found that chemical oxygen demand (COD) and total suspended solids (TSS) removal was satisfactory, with average values of 53 ± 18 and 69 ± 16%, respectively. Moreover, reducing HLRs resulted in higher removal efficiency for COD, from 46 ± 15 to 64 ± 15%, but had no impact on TSS removal, with 3 days of feeding and 6 days of resting. For an equal time of feeding and resting, COD and TSS removals were not affected by the modified HLR. These findings suggest that high HLRs can be applied to FS-FVFCW without compromising the system operation and obtaining satisfactory results, leading to opportunities to reduce areas and costs.

Chronbiologically-based sub-groups in bipolar I disorder: A latent profile analysis.

BACKGROUND: Bipolar disorder presents with significant phenotypic heterogeneity. The aim of this study was to investigate whether bipolar disorder, type I (BDI) subjects could be meaningfully classified into homogeneous groups according to activity, sleep, and circadian characteristics using latent profile analysis (LPA). We hypothesized that distinct BDI sub-groups would be identified based primarily on circadian-associated markers. MATERIALS AND METHODS: 105 individuals with BDI were included in the study. Seventeen activity, sleep, and circadian characteristics were assessed via actigraphy and clinical assessments. LPA was conducted to stratify our sample into homogenous sub-groups. Differences between groups on demographic, clinical, activity, sleep, and circadian characteristics were explored. RESULTS: Two distinct groups were identified, a High Chronobiological Disturbance group (HCD) (56%, N = 59) and a Low Chronobiological Disturbance group (LCD) (41%; N = 46). Circadian variables were the defining characteristics in sub-group determination. Large effect sizes and magnitudes of association were noted in circadian variables between HCD and LCD sub-groups. Several circadian rhythm variables accounted for a large percentage of the variance between HCD and LCD sub-groups. No differences were noted between sub-groups on demographic characteristics and the psychiatric medications currently in use. Mood state did not significantly impact sub-group differences. LIMITATIONS: The protocol was cross-sectional in design. Longitudinal studies are required to determine the stability of the identified sub-groups. CONCLUSION: LPA was able to identify sub-groups in BDI with circadian variables being the most distinguishing factors in determining sub-group class membership. Future research should explore the role that circadian characteristics can play in defining sub-phenotypes of bipolar disorder.

Carbon Nanotube Reinforced Poly(ε-caprolactone)/Epoxy Blends for Superior Mechanical and Self-Sensing Performance in Multiscale Glass Fiber Composites.

In this paper, a novel carbon nanotube (CNT) polycaprolactone (PCL), epoxy, and glass fiber (GF) composite is reported. Here, the nanoreinforced composites show a flexural strength increase of around 30%, whereas the interlaminar shear strength increases by 10-15% in comparison to unenhanced samples. This occurs because the addition of the CNTs induces a better PCL/epoxy/GF interaction. Furthermore, the nanoparticles also give novel functionalities to the multiscale composite, such as strain and damage monitoring. Here, the electrical response of the tensile- and compressive-subjected faces was simultaneously measured during flexural tests as well as the transverse conductivity in interlaminar tests, showing an exceptional capability for damage detection. Moreover, it was observed that the electrical sensitivity increases with PCL content due to a higher efficiency of the dispersion process that promotes the creation of a more uniform electrical network.

Correlación del grado de percepción y cultura de seguridad del paciente en una Institución de tercer nivel 2015-2019 / Correlação do grau de percepção e cultura da segurança do paciente em um hospital de nível terciário entre 2015-2019 / Correlation between the Degree of Perception and Culture on Patient Safety in a Tertiary Hospital between 2015-2019

Introducción: La seguridad del paciente es considerado como un patrón integrado de comportamiento individual y organizacional, basado en creencias y valores compartidos que continuamente busca minimizar el daño al paciente, que resulta de la atención. Objetivo: Analizar la correlación de percepción de cultura de seguridad del paciente, y grado de seguridad percibido en funcionarios de una Institución de Salud de tercer nivel de atención (2015-2017-2019). Materiales y Métodos: Estudio cuantitativo correlacional, con una muestra intencional derivada del registro de una base de datos de cultura de seguridad del paciente, con un total de 402 registros. La medición se realizó mediante el cuestionario Hospital Survey on Patient Safety Culture. Resultados: En los resultados globales el mayor porcentaje de encuestados correspondió al personal asistencial (73,4%). El principal servicio asistencial es unidad de cuidado intensivo (18,2%) y la mayor participación correspondió al rol de enfermeras y auxiliares de enfermería (45,7%). Según las respuestas positivas para los datos globales se determina 2 de 12 dimensiones clasificadas como fortaleza en el componente de Aprendizaje organizacional (81,5%) y Trabajo en equipo (85,5%) y el grado de seguridad percibido con correlaciones (p: 0,000) que se identifican en seis dimensiones entre ellas notificación de eventos, y aprendizaje organizacional. Discusión: La correlación del grado de seguridad percibido con las dimensiones del cuestionario guarda similitud en especial la notificación de eventos. Conclusión: La seguridad del paciente y el grado de seguridad percibido guardan correspondencia en la medida que en las instituciones realizan intervenciones en diferentes componentes entre ellos la notificación de eventos y trabajo en equipo.

Introduction: Patient safety is defined as an integrated pattern of individual and organizational behavior based on shared beliefs and values that continuously seeks to minimize harm to patients. Objective: To analyze the correlation between the perception of patient safety culture and the degree of safety perceived by healthcare workers in a tertiary hospital in 2015, 2017 and 2019. Materials and Methods: A quantitative correlational study was conducted with a purposive sample of 402 records obtained from a patient safety culture database. The Hospital Survey on Patient Safety Culture was used for assessment. Results: The global results show that the highest percentage of respondents corresponded to healthcare workers (73.4%). The main healthcare service provided is the intensive care unit (18.2%) in which most participants were nurses (45.7%). According to positive responses received for global data, 2 out of the 12 dimensions are classified as strengths in the Organizational Learning (81.5%) and Teamwork (85.5%) components, as well as the degree of safety perceived through correlations (p: 0.000) is found in five dimensions such as event notifications and organizational learning, among others. Discussion: The correlation between the perceived degree of safety and survey dimensions shows similarity, especially for event notifications. Conclusion: Patient safety and the perceived degree of safety are correlated as institutional interventions are made for different components, including organizational learning and teamwork.

Introdução: A segurança dos pacientes é definida como um padrão integrado de comportamento individual e organizacional baseado em crenças e valores compartilhados que busca continuamente minimizar os danos aos pacientes. Objetivo: Analisar a correlação entre a percepção da cultura de segurança do paciente e o grau de segurança percebido pelos profissionais de saúde em um hospital de nível terciário em 2015, 2017 e 2019. Materiais e Métodos: Um estudo correlacional quantitativo foi realizado com uma amostra proposital de 402 registros obtidos de um banco de dados de cultura de segurança do paciente. A Pesquisa sobre Cultura de Segurança dos Pacientes em Hospitais foi utilizada para a avaliação. Resultados: Os resultados globais mostram que a maior porcentagem de entrevistados correspondeu a trabalhadores da área de saúde (73,4%). O principal serviço de saúde prestado é a unidade de terapia intensiva (18,2%) e a maioria dos participantes eram enfermeiros (45,7%). De acordo com as respostas positivas recebidas para os dados globais, 2 das 12 dimensões são classificadas como pontos fortes nos componentes Aprendizagem Organizacional (81,5%) e Trabalho em Equipe (85,5%), assim como o grau de segurança percebido através de correlações (p: 0,000) é encontrado em cinco dimensões, tais como notificações de eventos e aprendizagem organizacional, entre outras. Discussão: A correlação do grau de segurança percebido com as dimensões da pesquisa é particularmente semelhante à notificação de eventos. Conclusão: A segurança do paciente e o grau de segurança percebido são correspondentes à medida que são feitas intervenções institucionais para diferentes componentes, incluindo o aprendizado organizacional e o trabalho em equipe.

Paciente ambulatorio y hospitalizado, estado actual de la evidencia para la prevención de caídas / Outpatient and hospitalized patient, actual state of evidence for fall prevention

Introducción: el envejecimiento de la población genera un incremento de la prevalencia de distintos procesos patológicos, generando un aumento de la estancia de los pacientes hospitalizados y demanda de atención ambulatoria. Estos mismos procesos patológicos se clasifican como factores de riesgos de caídas. Reportándose las caídas como el tercer evento adverso más notificado por la Joint Commission International para el año 2015. Objetivo: identificar los factores de riesgos, determinar las principales recomendaciones dadas por la literatura y correlacionar cuatro intervenciones NIC para disminuir las caídas. Metodología: revisión sistemática de literatura, con formato PICOT (Problema, Intervención, Comparador, Resultado y Tiempo) utilizando terminología DeCS y MeSH, Búsqueda en 5 bases de datos online e inclusión de estudios de los últimos 5 años, en tres idiomas. Inclusión de estudios secundarios, criterio de valoración crítica metodológica de la literatura CASPe, escala JADAD y AGREE. Resultados: se identifican 588 estudios, 83 cumplen con criterios de inclusión, valoración crítica de 55 y 31 estudios fueron seleccionados. Conclusión: la valoración del riesgo de caídas y las intervenciones de identificación del riesgo, son la piedra angular de prevención en la atención integral de seguridad del paciente hospitalizado y ambulatorio.

Introduction: The aging of population generates an increase in prevalence of different pathological processes, generating an increase in the stay of hospitalized patients and demand for outpatient care. These same pathological processes are classified as risk factors of fall. Reporting the falls as the third most reported adverse event by Joint Commission International for 2015. Objective: Identify risk factors, determine the main recommendations given by the literature and correlate four NIC interventions to reduce falls. Methods: Systematic review of literature, with PICOT format (Problem, Intervention, Comparator, Outcome and Time) using DeCS and MeSH terminology, Search in 5 online databases and inclusión of studies from the last 5 years, in three languages. Inclusión of secondary studies, criterion of critical methodological assessment of CASPe literature, JADAD and AGREE scale. Results: 588 studies are identified, 83 meet inclusión criteria, critical assessment of 55 and 31 studies were selected. Conclusión: The risk assessment of falls and risk identification interventions are the cornerstone of prevention in the integral safety care of the hospitalized and outpatient patient.

Point-of-Encounter Assessment: Using Health Belief Model Constructs to Change Grading Behaviors.

OBJECTIVE: Fourth-year medical students need feedback to improve. Even during 1-month rotations, there needs to be a formal mid-clerkship feedback session. Better feedback involves multiple surgical evaluators at multiple levels. Constructs from the Health Belief Model of behavior change were used to assess faculty and resident grading behaviors to create a more usable evaluation system. A point-of-encounter (POE) system was created. The objective of this study was to review the efficacy of a POE clinical evaluation card (CEC) system which was initiated to increase evaluator's participation in grading and formative feedback prior to mid-clerkship evaluation. DESIGN: The study was a 1-year retrospective cohort study reviewing the CECs for level of evaluator, content, and student compliance. A Likert-type scale survey regarding the usage of the clinical cards was also completed by evaluators. SETTING: Texas Tech University Health Sciences Center at El Paso, during 2 fourth-year medical student rotations, Subinternship (Sub-I), and Surgical Intensive Care Unit (SICU). PARTICIPANTS: 34 fourth-year medical students and 20 evaluators. RESULTS: Students turned in a mean of 10 cards, 75% in SICU and 65% in Sub-I turned in all 10 cards. There were significantly greater advanced residents evaluating during Sub-I vs SICU: mean evals by PGY3 were 1.9 vs 0.75 (p = .01) and mean evals by PGY5 were 1.4 vs 0.1 (p < .0001). There were significantly more faculty completing evaluations during SICU vs Sub-I: 2.5 faculty evals/student vs 1.4 faculty evals/student (p = .023). Evaluator ratings were high on a 5-point Likert-type scale, with most responses near the "strongly agree" rating of 4.7 to 4.8. CONCLUSIONS: Use of POE CECs met goals of having at least 7 CECs turned in by mid-clerkship and 10 at end-clerkships. Formative evaluations by mid-clerkship went from 0 to 7 evaluations. Evaluator surveys highlighted clarity and efficiency as reasons for using CECs.

Report of Adverse Events in Colombia: A Successful Case.

BACKGROUND: The Colombian National Food and Drug Surveillance Institute (INVIMA) is responsible for monitoring the safety and efficacy of medicines circulating the Colombian market. DISCUSSION: This article summarizes the three key strategies the institution has implemented to strengthen the National Pharmacovigilance Program: improving the interaction and working relationship with regional health authorities, expanding the National Pharmacovigilance Network and implementing the electronic submission of adverse events. CONCLUSION: The number of adverse events reported in Colombia increased from 5,447 in 2013 to 95,658 in 2017, reaching a population-based reporting ratio within international standards (563 in 2016).

An integrated mechanistic modeling of a facultative pond: Parameter estimation and uncertainty analysis.

Imitating natural lakes, pond treatment systems inherit a high complexity with interconnected web of biochemical reactions and complex hydraulic processes. As such, its simulation requires a large and integrated model, which has been a challenge for pond engineers. In this study, we develop an all-encompassing model to gain a quantitative and comprehensive understanding of the hydraulic, physicochemical and microbiological conversion processes in the most common pond, a facultative pond. Moreover, to deal with an evitable issue of large mechanistic models as overparameterization leading to poor identifiability, a systematic parameter estimation was implemented. The application of sensitivity analysis reveals the most influential parameters on pond performance. Particularly, physical parameters, such as vertical eddy diffusivity, water temperature, and maximum growth rate of heterotrophs induce the most changes of organic matters while microbial assimilation and ammonia volatilization appear to be main processes for nutrient removal. In contrast, the efficiency of phosphate precipitation and nutrient biological removal via polyphosphate accumulating organisms and denitrifying bacteria is limited. Identifiability problems are addressed mainly by the characterization of light dependence of algal growth, interaction between water temperature and its coefficient, and the growth of autotrophic bacteria while based on the determinant measures, the most important parameter subsets affecting model outputs are related to physical processes and algal activity. After the establishment of the influential and identifiable parameter subset, an automatic calibration with the data collected from Ucubamba pond system (Ecuador) demonstrates the effect of high-altitude climatic conditions on pond behaviors. An aerobic prevailing condition is observed as a result of high light intensity causing accelerated algal activities, hence, leading to the limitation of hydrolysis, anaerobic processes, and the growth of anoxic heterotrophs for denitrification. Furthermore, the output of uncertainty analysis indicates that a large avoidable uncertainty as a result of vast complexity of the applied model can be reduced greatly via a systematic approach for parameter estimation.

Exploring the influence of meteorological conditions on the performance of a waste stabilization pond at high altitude with structural equation modeling.

Algal photosynthesis plays a key role in the removal mechanisms of waste stabilization ponds (WSPs), which is indicated in the variations of three parameters, dissolved oxygen, pH, and chlorophyll a. These variations can be considerably affected by extreme climatic conditions at high altitude. To investigate these effects, three sampling campaigns were conducted in a high-altitude WSP in Cuenca (Ecuador). From the collected data, the first application of structure equation modeling (SEM) on a pond system was fitted to analyze the influence of high-altitude characteristics on pond performance, especially on the three indicators. Noticeably, air temperature appeared as the highest influencing factors as low temperature at high altitude can greatly decrease the growth rate of microorganisms. Strong wind and large diurnal variations of temperature, 7-20 °C, enhanced flow efficiency by improving mixing inside the ponds. Intense solar radiation brought both advantages and disadvantages as it boosted oxygen level during the day but promoted algal overgrowth causing oxygen depletion during the night. From these findings, the authors proposed insightful recommendations for future design, monitoring, and operation of high-altitude WSPs. Moreover, we also recommended SEM to pond engineers as an effective tool for better simulation of such complex systems like WSPs.

Disparities in breast cancer: a multi-institutional comparative analysis focusing on American Hispanics.

Breast cancer (BC) is the leading cause of cancer death in Hispanic/Latino women nationwide. Hispanic women are more likely to be presented with advanced disease and adverse prognosis subtypes. The aim of this study is to describe the clinico- pathological characteristics and disparities in breast cancer in this group at two tertiary care University-based medical centers. After IRB approval, Cancer registry was used to analyze the variables of 3441 patients with breast cancer diagnosed and treated consecutively at two large tertiary University based medical and cancer center database centers in El Paso, TX and Loma Linda, CA between 2005 and 2015. Association between race/ethnicity and cancer type, stage, hormone receptor status and treatment option were investigated. Overall 45.5% of the patients were Hispanic (n: 1566) and those were more likely to be diagnosed at a younger age (57 years) similar to African Americans, more likely to have invasive ductal carcinoma type (82.7%) & triple negative disease (17.1%, 95%CI: 15% to 19%). 58.8% of Hispanics (95%CI: 56% to 61%) have hormone receptor (HR)+ & HER2- as opposed to 71% in non-Hispanic White people. In addition, Hispanic individuals presented with advanced stages of BC (25.3%, 95% CI: 23% to 28%) similar to African American (25.4%), and had a lower proportion of lumpectomy (50%) similar to African American (50%). When compared to African American patients, Hispanic patients had a higher prevalence of triple negative BC (17.11% in Hispanics Versus 13.86% in African American). CONCLUSION: Hispanics had significantly higher relative risk of advanced stages at presentation (Relative Risk Ratio (RRR) = 2.05, P < 0.001), triple negative tumors (RRR = 2.64, P < 0.0001), HER2 + /HR - disease (RRR = 1.77, P < 0.0001), and less HR+ /HER2- BC (RRR = 0.69, P < 0.0001). Hispanics and African Americans are diagnosed with breast cancer at a younger age, have a higher prevalence of Triple negative breast cancer, and are diagnosed at more advanced stages of disease. Increasing awareness and targeting minority populations for health promotion interventions, screening and early detection continue to be of paramount importance to reduce the burden of health disparities.

Hispanic Americans and Non-Hispanic White Americans Have a Similar Inflammatory Bowel Disease Phenotype: A Systematic Review with Meta-Analysis.

BACKGROUND: Inflammatory bowel disease (IBD) is a devastating immune-mediated disease on the rise in Hispanics living in the USA. Prior observational studies comparing IBD characteristics between Hispanics and non-Hispanic whites (NHW) have yielded mixed results. AIMS: We performed a meta-analysis of observational studies examining IBD phenotype in Hispanics compared to NHW. METHODS: We conducted a systematic search of US-based studies comparing IBD subtype (Ulcerative Colitis: UC or Crohn's disease: CD) and phenotype (disease location and behavior) between Hispanics and NHW. We evaluated differences in age at IBD diagnosis, the presence of family history and smoking history. A random effects model was chosen "a priori." Categorical and continuous variables were analyzed using odds ratio (OR) or standard mean difference (SMD), respectively. RESULTS: Seven studies were included with 687 Hispanics and 1586 NHW. UC was more common in Hispanics compared to NHW (OR 2.07, CI 1.13-3.79, p = 0.02). Location of disease was similar between Hispanics and NHW except for the presence of upper gastrointestinal CD, which was less common in Hispanics (OR 0.58, CI 0.32-1.06, p = 0.07). Hispanics were less likely to smoke (OR 0.48, CI 0.26-0.89, p = 0.02) or have a family history of IBD (OR 0.35, CI 0.22-0.55, p < 0.001). CD behavior classified by Montreal classification and age at IBD diagnosis were similar between Hispanics and NHW. CONCLUSION: UC was more common among US Hispanics compared to NHW. Age at IBD diagnosis is similar for both Hispanics and NHW. For CD, disease behavior is similar, but Hispanics show a trend for less upper gastrointestinal involvement. A family history of IBD and smoking history were less common in Hispanics.

The association between mood state and chronobiological characteristics in bipolar I disorder: a naturalistic, variable cluster analysis-based study.

BACKGROUND: Multiple types of chronobiological disturbances have been reported in bipolar disorder, including characteristics associated with general activity levels, sleep, and rhythmicity. Previous studies have focused on examining the individual relationships between affective state and chronobiological characteristics. The aim of this study was to conduct a variable cluster analysis in order to ascertain how mood states are associated with chronobiological traits in bipolar I disorder (BDI). We hypothesized that manic symptomatology would be associated with disturbances of rhythm. RESULTS: Variable cluster analysis identified five chronobiological clusters in 105 BDI subjects. Cluster 1, comprising subjective sleep quality was associated with both mania and depression. Cluster 2, which comprised variables describing the degree of rhythmicity, was associated with mania. Significant associations between mood state and cluster analysis-identified chronobiological variables were noted. Disturbances of mood were associated with subjectively assessed sleep disturbances as opposed to objectively determined, actigraphy-based sleep variables. No associations with general activity variables were noted. Relationships between gender and medication classes in use and cluster analysis-identified chronobiological characteristics were noted. Exploratory analyses noted that medication class had a larger impact on these relationships than the number of psychiatric medications in use. CONCLUSIONS: In a BDI sample, variable cluster analysis was able to group related chronobiological variables. The results support our primary hypothesis that mood state, particularly mania, is associated with chronobiological disturbances. Further research is required in order to define these relationships and to determine the directionality of the associations between mood state and chronobiological characteristics.

Comparison of Health Examination Survey Methods in Brazil, Chile, Colombia, Mexico, England, Scotland, and the United States.

Comparability of population surveys across countries is key to appraising trends in population health. Achieving this requires deep understanding of the methods used in these surveys to examine the extent to which the measurements are comparable. In this study, we obtained detailed protocols of 8 nationally representative surveys from 2007-2013 from Brazil, Chile, Colombia, Mexico, the United Kingdom (England and Scotland), and the United States-countries that that differ in economic and inequity indicators. Data were collected on sampling frame, sample selection procedures, recruitment, data collection methods, content of interview and examination modules, and measurement protocols. We also assessed their adherence to the World Health Organization's "STEPwise Approach to Surveillance" framework for population health surveys. The surveys, which included half a million participants, were highly comparable on sampling methodology, survey questions, and anthropometric measurements. Heterogeneity was found for physical activity questionnaires and biological samples collection. The common age range included by the surveys was adults aged 18-64 years. The methods used in these surveys were similar enough to enable comparative analyses of the data across the 7 countries. This comparability is crucial in assessing and comparing national and subgroup population health, and to assisting the transfer of research and policy knowledge across countries.

Degenerate primer MOB typing of multiresistant clinical isolates of E. coli uncovers new plasmid backbones.

Degenerate Primer MOB Typing is a PCR-based protocol for the classification of γ-proteobacterial transmissible plasmids in five phylogenetic relaxase MOB families. It was applied to a multiresistant E. coli collection, previously characterized by PCR-based replicon-typing, in order to compare both methods. Plasmids from 32 clinical isolates of multiresistant E. coli (19 extended spectrum beta-lactamase producers and 13 non producers) and their transconjugants were analyzed. A total of 95 relaxases were detected, at least one per isolate, underscoring the high potential of these strains for antibiotic-resistance transmission. MOBP12 and MOBF12 plasmids were the most abundant. Most MOB subfamilies detected were present in both subsets of the collection, indicating a shared mobilome among multiresistant E. coli. The plasmid profile obtained by both methods was compared, which provided useful data upon which decisions related to the implementation of detection methods in the clinic could be based. The phylogenetic depth at which replicon and MOB-typing classify plasmids is different. While replicon-typing aims at plasmid replication regions with non-degenerate primers, MOB-typing classifies plasmids into relaxase subfamilies using degenerate primers. As a result, MOB-typing provides a deeper phylogenetic depth than replicon-typing and new plasmid groups are uncovered. Significantly, MOB typing identified 17 plasmids and an integrative and conjugative element, which were not detected by replicon-typing. Four of these backbones were different from previously reported elements.

CFD study to determine the optimal configuration of aerators in a full-scale waste stabilization pond.

Aerated lagoons (ALs) are important variants of the pond wastewater treatment technology that have not received much attention in the literature. The hydraulic behaviour of ALs and especially the Facultative aerated lagoons (FALs) is very complex since the aeration in these systems is designed for oxygen transfer but not necessarily to create complete mixing. In this work, the energy expenditure of the aerators was studied by means of a scenario analysis. 3D CFD models (one phase and multiphase) of a 3 ha FAL in a waste stabilization pond system in Cuenca (Ecuador) were built for different configurations of aerators. The thrust produced by the aerators was modelled by an external momentum source applied as velocity vectors into the pond fluid. The predictions of a single phase model were in satisfactory agreement with experimental results. Subsequently, a scenario analysis assessing several aeration schemes with different numbers of aerators in operation were tested with respect to velocity profiles and residence time distribution (RTD) curves. This analysis showed that the aeration scheme with all 10 aerators switched on produces a similar hydraulic behaviour compared to using only 6 or 8 aerators. The current operational schemes comprise of switching off some aerators during the peak hours of the day and operating all 10 aerators during night. This current practice could be economically replaced by continuously operating 4 or 6 aerators without significantly affecting the overall mixing. Furthermore, a continuous mixing regime minimises the sediment oxygen demand enhancing the oxygen levels in the pond.

CFD analysis of sludge accumulation and hydraulic performance of a waste stabilization pond.

Sludge management in waste stabilization ponds (WSPs) is essential for safeguarding the system performance. Sludge accumulation patterns in WSPs are strongly influenced by the pond hydrodynamics. CFD modeling was applied to study the relation between velocity profiles and sludge deposition during 10 years of operation of the Ucubamba WSP in Cuenca (Ecuador). One tracer experiment was performed and three sludge accumulation scenarios based on bathymetric surveys were simulated. A residence time distribution (RTD) analysis illustrated the decrease of residence times due to sludge deposition. Sludge accumulation rates were calculated. The influence of flow pattern on the sludge deposition was studied, enabling better planning of future pond operation and desludging.

A degenerate primer MOB typing (DPMT) method to classify gamma-proteobacterial plasmids in clinical and environmental settings.

Transmissible plasmids are responsible for the spread of genetic determinants, such as antibiotic resistance or virulence traits, causing a large ecological and epidemiological impact. Transmissible plasmids, either conjugative or mobilizable, have in common the presence of a relaxase gene. Relaxases were previously classified in six protein families according to their phylogeny. Degenerate primers hybridizing to coding sequences of conserved amino acid motifs were designed to amplify related relaxase genes from γ-Proteobacterial plasmids. Specificity and sensitivity of a selected set of 19 primer pairs were first tested using a collection of 33 reference relaxases, representing the diversity of γ-Proteobacterial plasmids. The validated set was then applied to the analysis of two plasmid collections obtained from clinical isolates. The relaxase screening method, which we call "Degenerate Primer MOB Typing" or DPMT, detected not only most known Inc/Rep groups, but also a plethora of plasmids not previously assigned to any Inc group or Rep-type.

Plasmid typing and genetic context of AmpC ß-lactamases in Enterobacteriaceae lacking inducible chromosomal ampC genes: findings from a Spanish hospital 1999-2007.

OBJECTIVES: To gain insights into ampC transmission between bacterial strains. METHODS: We examined the genetic context of 117 acquired ampC genes from 27119 Enterobacteriaceae collected between 1999 and 2007. Plasmid analysis was carried out by PCR-based replicon or relaxase typing, S1-PFGE and Southern hybridization. I-CeuI/PFGE was used for isolates not characterized by plasmid analysis. PCR reactions were used to map the genetic organization of the ampC genes. RESULTS: Among the isolates studied, 81.2% of ampC genes were located on plasmids of known Inc/MOB groups, 7.7% were chromosomally located and 11.1% were not determined. A/C, I1 and K were the most commonly found replicons in plasmids carrying bla(CMY-2), while L/M replicons were associated with bla(DHA-1). bla(ACC-1) was linked to I1 and MOB(F11) plasmids; bla(CMY-27) was associated with IncF and MOB(P12) plasmids; the plasmid carrying bla(CMY-25) could not be typed, and bla(CMY-40) was chromosomally located. All 87 isolates carrying bla(CMY-2), bla(CMY-4), bla(CMY-25), bla(CMY-27), bla(CMY-40) or bla(ACC-1) displayed the transposon-like structures ISEcp1/ΔISEcp1-bla(CMY)-blc-sugE or ΔISEcp1-bla(ACC-1)-gdha. The most prevalent structure in bla(DHA-1) (93.3% of cases) was identical to that described in the Klebsiella pneumoniae pTN60013 plasmid. Remarkably, in three isolates containing chromosomal bla(CMY-2), this gene was mobilized by conjugation. CONCLUSIONS: Although plasmids are the main cause of the rapid dissemination of ampC genes among bacteria, we need to be aware that other mobile genetic elements such as integrative and conjugative elements (ICEs) can be involved in the mobilization of these genes.

A compartmental model to describe hydraulics in a full-scale waste stabilization pond.

The advancement of experimental and computational resources has facilitated the use of computational fluid dynamics (CFD) models as a predictive tool for mixing behaviour in full-scale waste stabilization pond systems. However, in view of combining hydraulic behaviour with a biokinetic process model, the computational load is still too high for practical use. This contribution presents a method that uses a validated CFD model with tracer experiments as a platform for the development of a simpler compartmental model (CM) to describe the hydraulics in a full-scale maturation pond (7 ha) of a waste stabilization ponds complex in Cuenca (Ecuador). 3D CFD models were validated with experimental data from pulse tracer experiments, showing a sufficient agreement. Based on the CFD model results, a number of compartments were selected considering the turbulence characteristics of the flow, the residence time distribution (RTD) curves and the dominant velocity component at different pond locations. The arrangement of compartments based on the introduction of recirculation flow rate between adjacent compartments, which in turn is dependent on the turbulence diffusion coefficient, is illustrated. Simulated RTD's from a systemic tanks-in-series (TIS) model and the developed CM were compared. The TIS was unable to capture the measured RTD, whereas the CM predicted convincingly the peaks and lags of the tracer experiment using only a minimal fraction of the computational demand of the CFD model. Finally, a biokinetic model was coupled to both approaches demonstrating the impact an insufficient hydraulic model can have on the outcome of a modelling exercise. TIS and CM showed drastic differences in the output loads implying that the CM approach is to be used when modelling the biological performance of the full-scale system.