1,183 research outputs found
Efficacy of different antifouling treatments for seawater cooling systems
In an industrial seawater cooling system, the effects of three different antifouling treatments, viz. sodium
hypochlorite (NaClO), aliphatic amines (Mexel1432) and UV radiation, on the characteristics of the fouling formed
were evaluated. For this study a portable pilot plant, as a side-stream monitoring system and seawater cooling
system, was employed. The pilot plant simulated a power plant steam condenser, having four titanium tubes under
different treatment patterns, where fouling progression could be monitored. The nature of the fouling obtained was
chiefly inorganic, showing a clear dependence on the antifouling treatment employed. After 72 days the tubes under
treatment showed a reduction in the heat transfer resistance (R) of around 70% for NaClO, 48% for aliphatic
amines and 55% for UV, with respect to the untreated tube. The use of a logistic model was very useful for
predicting the fouling progression and the maximum asymptotic value of the increment in the heat transfer
resistance (DRmax). The apparent thermal conductivity (l) of the fouling layer showed a direct relationship with the
percentage of organic matter in the collected fouling. The characteristics and mode of action of the different
treatments used led to fouling with diverse physicochemical properties
Teoría y experimento en Genética Mendeliana: una exposición en imágenes
Corrección de errores en Theoria 64 : 105-111 (2009
Evaluation of bias correction methods for a multivariate drought index: case study of the Upper Jhelum Basin
Bias correction (BC) is often a necessity to improve the applicability of
global and regional climate model (GCM and RCM, respectively) outputs to
impact assessment studies, which usually depend on multiple potentially
dependent variables. To date, various BC methods have been developed which
adjust climate variables separately (univariate BC) or jointly (multivariate
BC) prior to their application in impact studies (i.e., the component-wise
approach). Another possible approach is to first calculate the multivariate
hazard index from the original, biased simulations and bias-correct the
impact model output or index itself using univariate methods (direct
approach). This has the advantage of circumventing the difficulties
associated with correcting the inter-variable dependence of climate
variables which is not considered by univariate BC methods.
Using a multivariate drought index (i.e., standardized precipitation
evapotranspiration index – SPEI) as an example, the present
study compares different state-of-the-art BC methods (univariate and
multivariate) and BC approaches (direct and component-wise) applied to
climate model simulations stemming from different experiments at different
spatial resolutions (namely Coordinated Regional Climate Downscaling Experiment (CORDEX), CORDEX Coordinated Output for Regional Evaluations (CORDEX-CORE), and 6th Coupled Intercomparison Project (CMIP6)). The BC methods
are calibrated and evaluated over the same historical period (1986–2005).
The proposed framework is demonstrated as a case study over a transboundary
watershed, i.e., the Upper Jhelum Basin (UJB) in the Western Himalayas.
Results show that (1) there is some added value of multivariate BC methods
over the univariate methods in adjusting the inter-variable relationship;
however, comparable performance is found for SPEI indices. (2) The best-performing BC methods exhibit a comparable performance under both approaches
with a slightly better performance for the direct approach. (3) The added
value of the high-resolution experiments (CORDEX-CORE) compared to their
coarser-resolution counterparts (CORDEX) is not apparent in this study.</p
Oxidative Stress Induced by Excess of Adiposity Is Related to a Downregulation of Hepatic SIRT6 Expression in Obese Individuals
Sirt6 is a member of the sirtuin family involved in physiological and pathological processes including aging, cancer, obesity, diabetes, and energy metabolism. This study is aimed at evaluating the relationship between liver SIRT6 gene expression and the oxidative stress network depending on adiposity levels in Zucker rats, an animal model of metabolic syndrome. We observed that liver-specific SIRT6 expression is reduced in an in vivo model of spontaneous obesity and metabolic syndrome. We also observed that SIRT6 expression in the liver is positively associated with SIRT1 and GST-M2 expressions, two proteins involved in antioxidant protection pathways and inversely related to body weight and plasmatic oxidative status. Interestingly, the SIRT6 expression is upregulated after energy restriction-induced weight loss concomitantly with an improvement in oxidative stress markers. These results suggest that SIRT6 may be a potential therapeutic target for the treatment of obesity and associated metabolic disorders, such as liver disease.Centro de Investigacion Biomedica en Red de Fisiopatologia de la Obesidad y Nutricion (CIBERobn)Instituto de Salud Carlos IIIEuropean Regional Development Fund (FEDER
Contaminations contaminate common databases
The polymerase chain reaction (PCR) is a very powerful method to detect and identify pathogens. The high sensitivity of the method, however, comes with a cost; any of the millions of artificial DNA copies generated by PCR can serve as a template in a following experiment. If not identified as contaminations, these may result in erroneous conclusions on the occurrence of the pathogen, thereby inflating estimates of host range and geographic distribution. In the present paper, we evaluate whether several published records of avian haemosporidian parasites, in either unusual host species or geographical regions, might stem from PCR contaminations rather than novel biological findings. The detailed descriptions of these cases are shedding light upon the steps in the work process that might lead to PCR contaminations. By increasing the awareness of this problem, it will aid in developing procedures that keep these to a minimum. The examples in the present paper are from haemosporidians of birds, however the problem of contaminations and suggested actions should apply generally to all kinds of PCR‐based identifications, not just of parasites and pathogens
Changes in prevalence of obesity and high waist circumference over four years across European regions: the European male ageing study (EMAS).
Diversity in lifestyles and socioeconomic status among European populations, and recent socio-political and economic changes in transitional countries, may affect changes in adiposity. We aimed to determine whether change in the prevalence of obesity varies between the socio-politically transitional North-East European (Łódź, Poland; Szeged, Hungary; Tartu, Estonia), and the non-transitional Mediterranean (Santiago de Compostela, Spain; Florence, Italy) and North-West European (Leuven, Belgium; Malmö, Sweden; Manchester, UK) cities. This prospective observational cohort survey was performed between 2003 and 2005 at baseline and followed up between 2008 and 2010 of 3369 community-dwelling men aged 40-79 years. Main outcome measures in the present paper included waist circumference, body mass index and mid-upper arm muscle area. Baseline prevalence of waist circumference ≥ 102 cm and body mass index ≥ 30 kg/m2, respectively, were 39.0, 29.5 % in North-East European cities, 32.4, 21.9 % in Mediterranean cities, and 30.0, 20.1 % in North-West European cities. After median 4.3 years, men living in cities from transitional countries had mean gains in waist circumference (1.1 cm) and body mass index (0.2 kg/m2), which were greater than men in cities from non-transitional countries (P = 0.005). North-East European cities had greater gains in waist circumference (1.5 cm) than in Mediterranean cities (P < 0.001). Over 4.3 years, the prevalence of waist circumference ≥ 102 cm had increased by 13.1 % in North-East European cities, 5.8 % in the Mediterranean cities, 10.0 % in North-West European cities. Odds ratios (95 % confidence intervals), adjusted for lifestyle factors, for developing waist circumference ≥ 102 cm, compared with men from Mediterranean cities, were 2.3 (1.5-3.5) in North-East European cities and 1.6 (1.1-2.4) in North-West European cities, and 1.6 (1.2-2.1) in men living in cities from transitional, compared with cities from non-transitional countries. These regional differences in increased prevalence of waist circumference ≥ 102 cm were more pronounced in men aged 60-79 years than in those aged 40-59 years. Overall there was an increase in the prevalence of obesity (body mass index ≥ 30 kg/m2) over 4.3 years (between 5.3 and 6.1 %) with no significant regional differences at any age. Mid-upper arm muscle area declined during follow-up with the greatest decline among men from North-East European cities. In conclusion, increasing waist circumference is dissociated from change in body mass index and most rapid among men living in cities from transitional North-East European countries, presumably driven by economic and socio-political changes. Information on women would also be of value and it would be of interest to relate the changes in adiposity to dietary and other behavioural habits
Epigenetic Landscape in Blood Leukocytes Following Ketosis and Weight Loss Induced by a Very Low Calorie Ketogenic Diet (VLCKD) in Patients With Obesity
[Abstract] Background:The molecular mechanisms underlying the potential health benefits of a ketogenic diet areunknown and could be mediated by epigenetic mechanisms.Objective:To identify the changes in the obesity-related methylome that are mediated by the inducedweight loss or are dependent on ketosis in subjects with obesity underwent a very-low calorie ketogenicdiet (VLCKD).Methods:Twenty-one patients with obesity (n¼12 women, 47.9±1.02 yr, 33.0±0.2 kg/m2) after 6months on a VLCKD and 12 normal weight volunteers (n¼6 women, 50.3±6.2 yrs, 22.7±1.5 kg/m2)were studied. Data from the Infinium MethylationEPIC BeadChip methylomes of blood leukocytes wereobtained at time points of ketotic phases (basal, maximum ketosis, and out of ketosis) during VLCKD(n¼10) and at baseline in volunteers (n¼12). Results were further validated by pyrosequencing inrepresentative cohort of patients on a VLCKD (n¼18) and correlated with gene expression.Results:After weight reduction by VLCKD, differences were found at 988 CpG sites (786 unique genes).The VLCKD altered methylation levels in patients with obesity had high resemblance with those fromnormal weight volunteers and was concomitant with a downregulation of DNA methyltransferases(DNMT)1, 3a and 3b. Most of the encoded genes were involved in metabolic processes, protein meta-bolism, and muscle, organ, and skeletal system development. Novel genes representing the top scoringassociated events were identified, includingZNF331,FGFRL1(VLCKD-induced weight loss) andCBFA2T3,C3orf38,JSRP1, andLRFN4(VLCKD-induced ketosis). Interestingly,ZNF331andFGFRL1were validated inan independent cohort and inversely correlated with gene expression.Conclusions:The beneficial effects of VLCKD therapy on obesity involve a methylome more suggestive ofnormal weight that could be mainly mediated by the VLCKD-induced ketosis rather than weight loss.This work was supported by the PronoKal Group® and grants from the Fondo de Investigacion Sanitaria as well as PI17/01287, PI20/00628 and PI20/00650 research projects and CIBERobn from the Instituto de Salud Carlos III (ISCIII)-Subdireccion General de Evaluacion y Fomento de la Investigación; Fondo Europeo de Desarrollo Regional (FEDER) Ana B Crujeiras is funded by a research contract “Miguel Servet” (CP17/00088) from the ISCIII, co-financed by the European Regional Development Fund (FEDER) and Xunta de Galicia-GAIN (IN607B2020)Xunta de Galicia; IN607B202
Epigenetic Landscape in Blood Leukocytes Following Ketosis and Weight Loss Induced by a Very Low Calorie Ketogenic Diet (VLCKD) in Patients with Obesity
Background: The molecular mechanisms underlying the potential health benefits of a ketogenic diet are
unknown and could be mediated by epigenetic mechanisms.
Objective: To identify the changes in the obesity-related methylome that are mediated by the induced
weight loss or are dependent on ketosis in subjects with obesity underwent a very-low calorie ketogenic
diet (VLCKD).
Methods: Twenty-one patients with obesity (n ¼ 12 women, 47.9 ± 1.02 yr, 33.0 ± 0.2 kg/m2
) after 6
months on a VLCKD and 12 normal weight volunteers (n ¼ 6 women, 50.3 ± 6.2 yrs, 22.7 ± 1.5 kg/m2
)
were studied. Data from the Infinium MethylationEPIC BeadChip methylomes of blood leukocytes were
obtained at time points of ketotic phases (basal, maximum ketosis, and out of ketosis) during VLCKD
(n ¼ 10) and at baseline in volunteers (n ¼ 12). Results were further validated by pyrosequencing in
representative cohort of patients on a VLCKD (n ¼ 18) and correlated with gene expression.
Results: After weight reduction by VLCKD, differences were found at 988 CpG sites (786 unique genes).
The VLCKD altered methylation levels in patients with obesity had high resemblance with those from
normal weight volunteers and was concomitant with a downregulation of DNA methyltransferases
(DNMT)1, 3a and 3b. Most of the encoded genes were involved in metabolic processes, protein metabolism, and muscle, organ, and skeletal system development. Novel genes representing the top scoring
associated events were identified, including ZNF331, FGFRL1 (VLCKD-induced weight loss) and CBFA2T3,
C3orf38, JSRP1, and LRFN4 (VLCKD-induced ketosis). Interestingly, ZNF331 and FGFRL1 were validated in
an independent cohort and inversely correlated with gene expression.
Conclusions: The beneficial effects of VLCKD therapy on obesity involve a methylome more suggestive of
normal weight that could be mainly mediated by the VLCKD-induced ketosis rather than weight loss.This work was supported by the PronoKal Group® and grants from the Fondo de Investigacion Sanitaria as well as PI17/01287, PI20/00628 and PI20/00650 research projects and CIBERobn from the Instituto de Salud Carlos III (ISCIII)-Subdireccion General de Evaluacion y Fomento de la Investigación; Fondo Europeo de Desarrollo Regional (FEDER) Ana B Crujeiras is funded by a research contract “Miguel Servet” (CP17/00088) from the ISCIII, co-financed by the European Regional Development Fund (FEDER) and Xunta de Galicia-GAIN (IN607B2020). The funding source had no involvement in the study design or interpretation of the result
The emerging structure of the Extended Evolutionary Synthesis: where does Evo-Devo fit in?
The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to ‘extend’ the Modern Synthesis-derived ‘standard evolutionary theory’ (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES—published by Laland and collaborators in 2015—in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework
The HEAT-SHIELD project - Perspectives from an inter-sectoral approach to occupational heat stress
Objectives: To provide perspectives from the HEAT-SHIELD project (www.heat-shield.eu): a multinational, inter-sectoral, and cross-disciplinary initiative, incorporating twenty European research institutions, as well as occupational health and industrial partners, on solutions to combat negative health and productivity effects caused by working on a warmer world. Methods: In this invited review, we focus on the theoretical and methodological advancements developed to combat occupational heat stress during the last five years of operation. Results: We outline how we created climate forecast models to incorporate humidity, wind and solar radiation to the traditional temperature-based climate projections, providing the basis for timely, policy-relevant, industry-specific and individualized information. Further, we summarise the industry-specific guidelines we developed regarding technical and biophysical cooling solutions considering effectiveness, cost, sustainability, and the practical implementation potential in outdoor and indoor settings, in addition to field-testing of selected solutions with time-motion analyses and biophysical evaluations. All recommendations were adjusted following feedback from workshops with employers, employees, safety officers, and adjacent stakeholders such as local or national health policy makers. The cross-scientific approach was also used for providing policy-relevant information based on socioeconomic analyses and identification of vulnerable regions considered to be more relevant for political actions than average continental recommendations and interventions. Discussion: From the HEAT-SHIELD experiences developed within European settings, we discuss how this inter-sectoral approach may be adopted or translated into actionable knowledge across continents where workers and societies are affected by escalating environmental temperatures.The study has received funding from the European Union’s Horizon 2020 research and innovation program under the grant agreement No 66878
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