Performance Analysis of DSOGI PLL under Balanced and Unbalanced Conditions

DPGS (distributed power generation system) gives an efficient and economic way of generating electricity by using renewable energy sources near to the load requirement. And it is the better way for reducing the transmission and distribution losses. But the process of synchronizing the DPGS system with grid is becoming one new challenge. As a consequence, the control of grid-connected power converters, grid synchronization method are very important because in order to implement stable control strategies under generic grid conditions a accurate and fast detecting method of the grid voltage characteristics is required .In actual practice the grid code requirements such as grid stability fault ride through, power quality improvement, power control and grid synchronization etc. should be satisfied by power plant operators. There are so many methods for grid synchronization , has been explained in the literature review to control the parameters like active and reactive power by tracking the phase angle of the supply grid voltage or grid current for proper synchronization of grid and DG system. In this thesis different types of grid synchronization system with DPGS system has been explained and later different types of PLL has been introduced for single phase and 3 phase system. For balanced 3 phase supply for getting better result SRF PLL is advisable, it uses the advanced method of conversion to 2 constant voltages from 2 orthogonal signals known as Park's transform and the Clarke's transform, it will take 3 phase supply as input and gives the 2 orthogonal signals as the output. But whenever the supply voltage is unbalanced the SRF PLL gives the output with the oscillating error means it is going to fail, so in case of the unbalanced supply voltage Decoupled Double Synchronous Reference Frame (DDSRF) PLL is suggested .the DDSRF PLL can detect the sequence components and positive sequence phase angle under unbalancing conditions. For generating the orthogonal signals Second Order Generalized Integrator (SOGI) is the better replacement of Clarke’s transform and it has high capacity of harmonic rejection because it can perform current controller duty and also sequence components also can be detected easily. For grid synchronization another advanced method is Dual Second Order Generalized Integrator - Phase Locked Loop (PLL) has been implemented by using Matlab simulink and LABVIEW under unbalanced conditions like sag and swell

Contribution to the simulation of new standard testing cycles by means of a 0D/1D tool

Tesis por compendio[ES] El objetivo principal de esta tesis es establecer una metodología para predecir el consumo de combustible y las emisiones de un motor de encendido por compresión en condiciones transitorias. Además, su objetivo es explorar cómo las diferentes configuraciones del motor y los factores ambientales impactan el comportamiento del motor utilizando un enfoque de modelado 0D/1D. Además, el estudio pretende extender esta metodología a los motores duales, analizando específicamente las características de combustión de metano-diésel e hidrógeno-diésel. Para lograrlo, la herramienta de modelado 0D/1D se ajustó y validó meticulosamente utilizando un motor diésel de cuatro cilindros. Esta alineación entre la simulación y datos experimentales se centró especialmente en factores cruciales como la presión, la liberación de calor, las temperaturas en los fluidos del motor y el par. Se realizó un análisis exhaustivo del Balance Energético Global (GEB) utilizando VEMOD (Virtual Engine Model). Este análisis proporcionó información detallada sobre el consumo del motor y su reacción en diversas condiciones de funcionamiento, particularmente durante el Ciclo de ensayo mundial armonizado de vehículos ligeros (WLTC). La comparación de términos energéticos entre diferentes condiciones ambientales y de motor destacó aspectos como la fricción, la transferencia de calor y la acumulación de calor. Además, el análisis GEB permitió explorar cómo se distribuía la energía con diferentes temperaturas y altitudes ambientes. El estudio también evaluó las emisiones de NOx, revelando patrones influenciados por factores como las tasas de recirculación de gases de escape (EGR) y la temperatura de admisión. En el ámbito de los motores de combustible dual, se elaboró y validó un modelo de combustión utilizando la herramienta de simulación 0D/1D. La atención inicial se centró en la combustión de metano-Diesel, validada con datos experimentales. Posteriormente, el alcance de este modelo se amplió para simular la combustión de hidrógeno-Diesel. Esta tesis ha introducido con éxito una metodología que utiliza VEMOD para predecir el consumo y las emisiones del motor en distintos escenarios. El análisis exhaustivo arrojó luz sobre cómo funcionan los mecanismos de distribución de energía y cómo diferentes factores influyen en el comportamiento del motor. La aplicación de esta metodología a motores de encendido por compresión ha demostrado su versatilidad y capacidad de predicción, lo que la convierte en una herramienta valiosa para investigar escenarios futuros, también con combustiones duales.[CA] L'objectiu principal d'aquesta tesi és establir una metodologia per predir el consum de combustible i les emissions d'un motor d'encesa per compressió en condicions transitòries. A més, pretén explorar com diferents configuracions de motors i factors ambientals afecten el comportament del motor mitjançant un enfocament de modelització 0D/1D. A més, l'estudi s'esforça a estendre aquesta metodologia als motors de doble combustible (duals), analitzant específicament les característiques de combustió de metà-dièsel i hidrogendièsel. Per aconseguir-ho, l'eina de modelització 0D/1D es va ajustar minuciosament i es va validar mitjançant un motor dièsel de quatre cilindres. Aquesta alineació entre dades de simulació i món real es va centrar especialment en factors crucials com la pressió, l'alliberament de calor, les temperatures dels fluids del motor i el parell. Es va realitzar una anàlisi completa del Balanç Global d'Energia (GEB) mitjançant VEMOD (Virtual Engine Model). Aquesta anàlisi va proporcionar una visió profunda sobre el consum del motor i la seua reacció en diverses condicions de funcionament, especialment durant el Cicle mundial d'assaig de vehicles lleugers harmonitzats (WLTC). La comparació de termes energètics entre diferents condicions ambientals i del motor van posar de manifest aspectes com la fricció, la transferència de calor i l'acumulació de calor. A més, l'anàlisi GEB va explorar com es va distribuir l'energia amb diferents temperatures i altituds ambientals. L'estudi també va valorar les emissions de NOx, revelant patrons influenciats per factors com la recirculació de gasos d'escapament (EGR) i la temperatura d'admissió. En l'àmbit dels motors duals, es va elaborar i validar un model de combustió mitjançant l'eina de simulació 0D/1D. El focus inicial es va centrar en la combustió metà-Diesel, validada amb dades experimentals. Posteriorment, l'abast d'aquest model es va ampliar per simular la combustió hidrogen-Diesel. Aquesta tesi ha introduït amb èxit una metodologia que utilitza VEMOD per predir el consum i les emissions del motor en diferents escenaris. L'anàlisi completa va donar llum a com funcionen els mecanismes de distribució d'energia i com diferents factors influeixen en el comportament del motor. L'aplicació d'aquesta metodologia als motors d'encesa per compressió va demostrar la seva versatilitat i capacitats de predicció, convertint-la en una valuosa eina per investigar els futurs escenaris, fins i tot amb combustions duals.[EN] The main aim of this thesis is to establish a methodology for predicting fuel consumption and emissions of a compression ignition engine in transient conditions. Additionally, it aims to explore how different engine setups and environmental factors impact the engine's performance using a 0D/1D modelling approach. Moreover, the study strives to extend this methodology to dual fuel engines, specifically analysing methane-Diesel and hydrogen- Diesel combustion characteristics. The 0D/1D modelling tool was meticulously fine-tuned and validated using a four-cylinder Diesel engine to achieve this. This alignment between simulation and experimental data focused on crucial factors such as pressure, heat release, engine fluid temperatures and torque. A comprehensive Global Energy Balance (GEB) analysis was conducted using VEMOD (Virtual Engine Model). This analysis provided insights into the engine consumption and performance under diverse operating conditions, particularly during the Worldwide Harmonized Light Vehicles Test Cycle (WLTC). The comparison of energy terms across different engine and boundary conditions highlighted aspects such as friction, heat rejection, and heat accumulation. Additionally, the GEB analysis allowed exploration of how energy was split across varying ambient temperatures and altitudes. The study also assessed NOx emissions, revealing patterns influenced by factors such as Exhaust Gas Recirculation (EGR) rates and intake temperature. A combustion model was developed and validated using the 0D/1D simulation tool in the scope of dual fuel engines. The initial focus was on methane-Diesel combustion, validated against experimental data. Subsequently, this model scope was expanded to simulate hydrogen-Diesel combustion. This thesis has successfully introduced a methodology based on VEMOD to predict engine consumption and emissions across varying scenarios. The comprehensive analysis illuminated how energy distribution mechanisms operate and how factors influence engine performances. The application of this methodology to compression ignition engines demonstrated its versatility and prediction capabilities, making it a valuable tool for investigating future combustion scenarios, including dual fuel operation.This research has been partially funded by the European Union’s Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 (“DiePeR”) and by the Spanish government under the grant agreement TRA2017-89894-R (”MECOEM”) and I was supported by FPI grant with reference PRE2018-084411.Artham, S. (2023). Contribution to the simulation of new standard testing cycles by means of a 0D/1D tool [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/201238Compendi

An Experimental Study of Momentum-Driven Unsteady Jets

Jets are seen commonly in nature and engineering and can be broadly classified into steady and unsteady jets. The study of unsteady jets has received little attention when compared to its steady counterpart. A type of unsteady jet is the turbulent puff which is a momentum driven jet in which fluid is ejected from a jet orifice intermittently. Common examples of turbulent puff like jets are coughs and volcanoes. The studies on momentum driven unsteady jets have primarily focused on single ejection events (single puffs) where an instantaneous supply of momentum drives the source fluid downstream of a nozzle. This work focuses on dual puffs in which two volumes of fluid (dual puffs), separated by a time ∆p are ejected from a jet orifice into ambient. An experimental framework to study such dual puffs with varying separation and ejected volume was built. The dual puffs studied were compared with both steady jets and single puffs. The mean velocity of these flow fields were measured using hot-wire anemometry. Complementary flow visualizations were also carried out. Dual puffs with ∆p = 0.3 s, 0.5 s, 0.7 s ans 1.79 s were considered. It was determined that for short time separations ∆pVj/d = 430, the dual puffs persisted for longer distances when compared to a single puff or dual puffs with larger time separation (∆pVj/d = 1540). Here Vj is the maximum jet exit velocity and the d the diameter of the jet orifice. However, at large time separation (∆pVj/d = 1540) the dual puffs expanded considerably more rapidly than dual puffs with smaller separation or single puffs. This indicates that the dual puff studied can be classified into two categories based on the time separation between the puffs. These observations are of an integral nature and a more detailed analysis of the flow field using advanced techniques as particle image velocimetry (PIV) are recommended to establish the precise flow physics leading to this behavior

Stage-Specific Effects of Hypoxia on Interstitial Lung Disease

Interstitial lung disease (ILD) comprises a group of lung diseases principally affecting the pulmonary interstitium, for example, pulmonary fibrosis. Following acute lung injury (ALI), the fate of an injured lung progressing towards either injury resolution or pulmonary fibrosis is dictated by hypoxia at various stages during the disease progression. Hypoxia that is tissue destructive at one stage of lung injury becomes beneficial at a different stage, with each hypoxic stage involving a different scheme of molecular pathways, cellular interplay and tissue remodeling. In this chapter, we provide a detailed account of hypoxia during the different stages of lung injury in ILDs, delineate the cellular and molecular mechanisms mediating tissue remodeling in the hypoxic lungs as well as the basic and clinical findings in this field with an emphasis on future therapeutics to modulate hypoxia to treat ILD

Analysis of the energy balance during World harmonized Light vehicles Test Cycle in warmed and cold conditions using a Virtual Engine

This is the author's version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087419878593.[EN] In recent years, the interests on transient operation and real driving emissions have increased because of the global concern about environmental pollution that has led to new emissions regulation and new standard testing cycles. In this framework, it is mandatory to focus the engines research on the transient operation, where a Virtual Engine has been used to perform the global energy balance of a 1.6-L diesel engine during a World harmonized Light vehicles Test Cycle. Thus, the energy repartition of the chemical energy has been described with warmed engine and cold start conditions, analyzing in detail the mechanisms affecting the engine consumption. The first analysis focuses on the ¿delay¿ effect affecting the instantaneous energy balance due to the time lag between the in-cylinder processes and pipes: as a main conclusion, it is obtained that it leads to an apparent unbalance than can reach more than 10% of the cumulated fuel energy at the beginning of the cycle, becoming later negligible. Energy split analysis in cold starting World harmonized Light vehicles Test Cycle shows that in this condition the energy accumulation in the block is a key term at the beginning (about 50%) that diminishes its weight until about 10% at the end of the cycle. In warmed conditions, energy accumulation is negligible, but the heat transfer to coolant and oil are higher than in cold starting conditions (21% vs 28%). The lower values of the mean brake efficiency at the beginning of the World harmonized Light vehicles Test Cycle (only about 20%) is affected, especially in cold starting, by the higher mechanical losses due to the higher oil viscosity and the heat rejection from the gases. The friction plays an important role only during the first half of the cycle, with a percentage of about 65% of the total mechanical losses and 10% of the total fuel energy at the end of the World harmonized Light vehicles Test Cycle. However, at the end of the cycle, it does not affect dramatically the mean brake efficiency which is about 31% both in cold starting and warmed World harmonized Light vehicles Test Cycle.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This research has been partially funded by the European Union's Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 ("DiePeR'') and by the Spanish government under the grant agreement TRA2017-89894-R. The authors wish to thank Renault SAS, especially P. Mallet and E. Gaiffas, for supporting this research.Olmeda, P.; Martín, J.; Arnau Martínez, FJ.; Artham, S. (2020). Analysis of the energy balance during World harmonized Light vehicles Test Cycle in warmed and cold conditions using a Virtual Engine. International Journal of Engine Research. 21(6):1037-1054. https://doi.org/10.1177/1468087419878593S10371054216Tauzia, X., Maiboom, A., Karaky, H., & Chesse, P. (2018). Experimental analysis of the influence of coolant and oil temperature on combustion and emissions in an automotive diesel engine. International Journal of Engine Research, 20(2), 247-260. doi:10.1177/1468087417749391Payri, F., Olmeda, P., Martin, J., & Carreño, R. (2014). A New Tool to Perform Global Energy Balances in DI Diesel Engines. SAE International Journal of Engines, 7(1), 43-59. doi:10.4271/2014-01-0665Tauzia, X., & Maiboom, A. (2013). Experimental study of an automotive Diesel engine efficiency when running under stoichiometric conditions. Applied Energy, 105, 116-124. doi:10.1016/j.apenergy.2012.12.034Abedin, M. J., Masjuki, H. H., Kalam, M. A., Sanjid, A., Rahman, S. M. A., & Masum, B. M. (2013). Energy balance of internal combustion engines using alternative fuels. Renewable and Sustainable Energy Reviews, 26, 20-33. doi:10.1016/j.rser.2013.05.049Ajav, E. A., Singh, B., & Bhattacharya, T. K. (2000). Thermal balance of a single cylinder diesel engine operating on alternative fuels. Energy Conversion and Management, 41(14), 1533-1541. doi:10.1016/s0196-8904(99)00175-2DIMOPOULOS, P., BACH, C., SOLTIC, P., & BOULOUCHOS, K. (2008). Hydrogen–natural gas blends fuelling passenger car engines: Combustion, emissions and well-to-wheels assessment. International Journal of Hydrogen Energy, 33(23), 7224-7236. doi:10.1016/j.ijhydene.2008.07.012TAYMAZ, I. (2006). An experimental study of energy balance in low heat rejection diesel engine. Energy, 31(2-3), 364-371. doi:10.1016/j.energy.2005.02.004Olmeda, P., Martín, J., Novella, R., & Blanco-Cavero, D. (2018). Assessing the optimum combustion under constrained conditions. International Journal of Engine Research, 21(5), 811-823. doi:10.1177/1468087418814086Durgun, O., & Şahin, Z. (2009). Theoretical investigation of heat balance in direct injection (DI) diesel engines for neat diesel fuel and gasoline fumigation. Energy Conversion and Management, 50(1), 43-51. doi:10.1016/j.enconman.2008.09.007Jia, M., Gingrich, E., Wang, H., Li, Y., Ghandhi, J. B., & Reitz, R. D. (2015). Effect of combustion regime on in-cylinder heat transfer in internal combustion engines. International Journal of Engine Research, 17(3), 331-346. doi:10.1177/1468087415575647Jung, D., Yong, J., Choi, H., Song, H., & Min, K. (2013). Analysis of engine temperature and energy flow in diesel engine using engine thermal management. Journal of Mechanical Science and Technology, 27(2), 583-592. doi:10.1007/s12206-012-1235-4Caresana, F., Bilancia, M., & Bartolini, C. M. (2011). Numerical method for assessing the potential of smart engine thermal management: Application to a medium-upper segment passenger car. Applied Thermal Engineering, 31(16), 3559-3568. doi:10.1016/j.applthermaleng.2011.07.017Payri, F., López, J. J., Martín, J., & Carreño, R. (2018). Improvement and application of a methodology to perform the Global Energy Balance in internal combustion engines. Part 1: Global Energy Balance tool development and calibration. Energy, 152, 666-681. doi:10.1016/j.energy.2018.03.118Arrègle, J., López, J. J., Garcı́a, J. M., & Fenollosa, C. (2003). Development of a zero-dimensional Diesel combustion model. Applied Thermal Engineering, 23(11), 1319-1331. doi:10.1016/s1359-4311(03)00080-2Arrègle, J., López, J. J., Garcı́a, J. M., & Fenollosa, C. (2003). Development of a zero-dimensional Diesel combustion model. Part 1: Analysis of the quasi-steady diffusion combustion phase. Applied Thermal Engineering, 23(11), 1301-1317. doi:10.1016/s1359-4311(03)00079-6Benajes, J., Olmeda, P., Martín, J., & Carreño, R. (2014). A new methodology for uncertainties characterization in combustion diagnosis and thermodynamic modelling. Applied Thermal Engineering, 71(1), 389-399. doi:10.1016/j.applthermaleng.2014.07.010Payri, F., Olmeda, P., Martín, J., & Carreño, R. (2015). Experimental analysis of the global energy balance in a DI diesel engine. Applied Thermal Engineering, 89, 545-557. doi:10.1016/j.applthermaleng.2015.06.005Olmeda, P., Dolz, V., Arnau, F. J., & Reyes-Belmonte, M. A. (2013). Determination of heat flows inside turbochargers by means of a one dimensional lumped model. Mathematical and Computer Modelling, 57(7-8), 1847-1852. doi:10.1016/j.mcm.2011.11.078Torregrosa, A., Olmeda, P., Degraeuwe, B., & Reyes, M. (2006). A concise wall temperature model for DI Diesel engines. Applied Thermal Engineering, 26(11-12), 1320-1327. doi:10.1016/j.applthermaleng.2005.10.021Payri, R., Salvador, F. J., Gimeno, J., & Bracho, G. (2008). A NEW METHODOLOGY FOR CORRECTING THE SIGNAL CUMULATIVE PHENOMENON ON INJECTION RATE MEASUREMENTS. Experimental Techniques, 32(1), 46-49. doi:10.1111/j.1747-1567.2007.00188.xTormos, B., Martín, J., Carreño, R., & Ramírez, L. (2018). A general model to evaluate mechanical losses and auxiliary energy consumption in reciprocating internal combustion engines. Tribology International, 123, 161-179. doi:10.1016/j.triboint.2018.03.00

Analysis of temperature and altitude effects on the Global Energy Balance during WLTC

This is the author¿s version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/14680874211034292[EN] In this work, the Global Energy Balance (GEB) of a 1.6 L compression ignition engine is analyzed during WLTC using a combination of experimental measurements and simulations, by means of a Virtual Engine. The energy split considers all the relevant energy terms at two starting temperatures (20 degrees C and 7 degrees C) and two altitudes (0 and 1000 m). It is shown that reducing ambient temperature from 20 degrees C to -7 degrees C decreases brake efficiency by 1% and increases fuel consumption by 4%, mainly because of the higher friction due to the higher oil viscosity, while the effect of increasing altitude 1000 m decreases brake efficiency by 0.8% and increases fuel consumption by 2.5% in the WLTC mainly due to the change in pumping. In addition, GEB shows that ambient temperature is affecting exhaust enthalpy by 4.5%, heat rejection to coolant by 2%, and heat accumulated in the block by 2.5%, while altitude does not show any remarkable variations other than pumping and break power.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research has been partially funded by the European Union's Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 ("DiePeR'') and by the Spanish government under the grant agreement TRA2017-89894-R ("MECOEM'') and Sushma Artham was supported by FPI grant with reference PRE2018-084411. The authors wish to thank Renault SAS, especially P. Mallet and E. Gaiffas, for supporting this research.Payri, F.; Martín, J.; Arnau Martínez, FJ.; Artham, S. (2022). Analysis of temperature and altitude effects on the Global Energy Balance during WLTC. International Journal of Engine Research. 23(11):1831-1849. https://doi.org/10.1177/1468087421103429218311849231

Anemia and associated clinical outcomes in patients with heart failure due to reduced left ventricular systolic function.

BACKGROUND: Anemia is associated with decreased functional capacity, reduced quality of life, and worsened outcomes among patients with heart failure (HF) due to reduced left ventricular ejection fraction (HFREF). We sought to evaluate the independent effect of anemia on clinical outcomes among those with HFREF. HYPOTHESIS: Anemia is associated with cardiovascular events in patients with heart failure. METHODS: The HF-ACTION trial was a prospective, randomized trial of exercise therapy vs usual care in 2331 patients with HFREF. Patients with New York Heart Association class II to IV HF and left ventricular ejection fractions of ≤ 35% were recruited. Hemoglobin (Hb) was measured up to 1 year prior to entry and was stratified by quintile. Anemia was defined as baseline Hb/dL and/dL in men and women, respectively. Hemoglobin was assessed in 2 models: a global prediction model that had been previously developed, and a modified model including variables associated with anemia and the studied outcomes. RESULTS: Hemoglobin was available at baseline in 1763 subjects (76% of total study population); their median age was 59.0 years, 73% were male, and 62% were Caucasian. The prevalence of anemia was 515/1763 (29%). Older age, female sex, African American race, diabetes, hypertension, and lower estimated glomerular filtration rates were all more frequent in lower Hb quintiles. Over a median follow-up of 30 months, the primary outcome of all-cause mortality or all-cause hospitalization occurred in 78% of those with anemia and 64% in those without (P \u3c 0.001). The secondary outcomes of all-cause mortality alone,cardiovascular (CV) mortality or CV hospitalization, and CV mortality or HF hospitalization occurred in 23% vs 15%, 67% vs 54%, and 44 vs 29%, respectively (P \u3c 0.001). Heart failure hospitalizations occurred in 36% vs 22%, and urgent outpatient visits for HF exacerbations occurred in 67% and 55%, respectively (P \u3c 0.001). For the global model, there was an association observed for anemia and all-cause mortality or hospitalization (adjusted hazard ratio [HR]: 1.15, 95% confidence interval [CI]: 1.01-1.32, P = 0.04), but other outcomes were not significant at P \u3c 0.05. In the modified model, the adjusted HR for anemia and the primary outcome of all-cause mortality or all-cause hospitalization was 1.25 (95% CI: 1.10-1.42, P \u3c 0.001). There were independent associations between anemia and all-cause death (HR: 1.11, 95% CI: 0.87-1.42, P = 0.38), CV death or CV hospitalization (HR: 1.16, 95% CI: 1.01-1.33, P = 0.035), and CV death and HF hospitalization (HR: 1.27, 95% CI: 1.06-1.51, P = 0.008). CONCLUSIONS: Anemia modestly is associated with increased rates of death, hospitalization, and HF exacerbation in patients with chronic HFREF. After adjusting for other important covariates, anemia is independently associated with an excess hazard for all-cause mortality and all-cause hospitalization. Anemia is also associated with combinations of CV death and CV/HF hospitalizations as composite endpoints

The role of cigarette butts as vectors of metals in the marine environment: Could it cause bioaccumulation in oysters?

Tobacco is a well-documented threat to human health. However, its environmental impact has only recently been considered. Metals can interact with cigarette butts (CBs) being transported in the marine environment and reaching organisms. To understand this mechanism, a series of metal(loid)s were analyzed in cigarette filters (virgin, artificially smoked, leached in seawater and aged in beach and harbour) as well as in artificially contaminated oyster tissues. Smoked filters showed higher levels of metals compared to the virgin ones showing enrichment factors up to 90, probably associated with tobacco metal content. Once the CBs are delivered to the environment, metals can be leached to seawater until reaching equilibrium, which may be dependent on initial metal levels in the water. Copper was the element with the highest percentage of desorption (91 ± 3%) while strontium showed the lowest percentage (40 ± 0%). CBs revealed a great capacity to accumulate metals from the environment when weathered in contaminated areas. A chemical impact derived from CBs contamination might exist as they serve as a carrier for metals in the marine environment. The release of metals from CBs or the ingestion of metal loaded CBs may pose a toxicological risk for marine organisms via accumulation in their tissues.Versión del edito

Feasibility of MR-Based Body Composition Analysis in Large Scale Population Studies

Introduction Quantitative and accurate measurements of fat and muscle in the body are important for prevention and diagnosis of diseases related to obesity and muscle degeneration. Manually segmenting muscle and fat compartments in MR body-images is laborious and time-consuming, hindering implementation in large cohorts. In the present study, the feasibility and success-rate of a Dixon-based MR scan followed by an intensity-normalised, non-rigid, multi-atlas based segmentation was investigated in a cohort of 3,000 subjects. Materials and Methods 3,000 participants in the in-depth phenotyping arm of the UK Biobank imaging study underwent a comprehensive MR examination. All subjects were scanned using a 1.5 T MR-scanner with the dual-echo Dixon Vibe protocol, covering neck to knees. Subjects were scanned with six slabs in supine position, without localizer. Automated body composition analysis was performed using the AMRA Profiler™ system, to segment and quantify visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (ASAT) and thigh muscles. Technical quality assurance was performed and a standard set of acceptance/rejection criteria was established. Descriptive statistics were calculated for all volume measurements and quality assurance metrics. Results Of the 3,000 subjects, 2,995 (99.83%) were analysable for body fat, 2,828 (94.27%) were analysable when body fat and one thigh was included, and 2,775 (92.50%) were fully analysable for body fat and both thigh muscles. Reasons for not being able to analyse datasets were mainly due to missing slabs in the acquisition, or patient positioned so that large parts of the volume was outside of the field-of-view. Discussion and Conclusions In conclusion, this study showed that the rapid UK Biobank MR-protocol was well tolerated by most subjects and sufficiently robust to achieve very high success-rate for body composition analysis. This research has been conducted using the UK Biobank Resource

A randomized controlled trial of metformin on left ventricular hypertrophy in patients with coronary artery disease without diabetes:the MET-REMODEL trial

Aim We tested the hypothesis that metformin may regress left ventricular hypertrophy (LVH) in patients who have coronary artery disease (CAD), with insulin resistance (IR) and/or pre-diabetes. Methods and results We randomly assigned 68 patients (mean age 65 ± 8 years) without diabetes who have CAD with IR and/or pre-diabetes to receive either metformin XL (2000 mg daily dose) or placebo for 12 months. Primary endpoint was change in left ventricular mass indexed to height1.7 (LVMI), assessed by magnetic resonance imaging. In the modified intention-to-treat analysis (n = 63), metformin treatment significantly reduced LVMI compared with placebo group (absolute mean difference −1.37 (95% confidence interval: −2.63 to −0.12, P = 0.033). Metformin also significantly reduced other secondary study endpoints such as: LVM (P = 0.032), body weight (P = 0.001), subcutaneous adipose tissue (P = 0.024), office systolic blood pressure (BP, P = 0.022) and concentration of thiobarbituric acid reactive substances, a biomarker for oxidative stress (P = 0.04). The glycated haemoglobin A1C concentration and fasting IR index did not differ between study groups at the end of the study. Conclusion Metformin treatment significantly reduced LVMI, LVM, office systolic BP, body weight, and oxidative stress. Although LVH is a good surrogate marker of cardiovascular (CV) outcome, conclusive evidence for the cardio-protective role of metformin is required from large CV outcomes trials