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Droughts can impact on forest functioning and production, and even lead to tree mortality. However, drought is an elusive phenomenon that is difficult to quantify and define universally. In this study, we assessed the performance of a set of indicators that have been used to describe drought conditions in the summer months (June, July, August) over a 30 year period (1981-2010) in Finland. Those indicators include the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), the Soil Moisture Index (SMI) and the Soil Moisture Anomaly (SMA). Herein, regional soil moisture was produced by the land surface model JSBACH. While SPI, SPEI, and SMA show a degree of anomalies from the statistical means over a period, SMI is directly connected to plant available water and closely dependent on soil properties. Moreover, the buffering effect of soil moisture and the associated soil moisture memory can impact on the onset and duration of drought as indicated by the SMI and SMA, whereas SPI and SPEI are directly controlled by meteorological conditions. In particular, we investigated whether the SMI, SMA and SPEI are able to indicate the Extreme Drought affecting Forest health (EDF) in Finland. EDF thresholds for these indicators are suggested, based on the spatially representative statistics of forest health observations in the exceptional dry year 2006. Our results showed that SMI was the best indicator in capturing the spatial extent of forest damage induced by the extreme drought in 2006. In addition, the derived thresholds were applied to those indicators to capture EDF events over the summer months of the 30 year study period. The SPEI and SMA showed more frequent EDF events over the 30 year period, and typically described a higher fraction of influenced area than SMI. In general, the suggested EDF thresholds for those indicators may be used for the indication of EDF events in Finland or other boreal forests areas in the context of future climate scenarios. However, the results have to be interpreted carefully, with due consideration of their different properties and the complexity of drought. Our results would suggest that in order to take appropriate precautions to mitigate against possible forest losses, an integrated analysis of projected drought with drought indicators is recommended. [ABSTRACT FROM AUTHOR]

We studied the commencement and finishing of the growing season using different air temperature indices, the surface albedo, the chlorophyll fluorescence (Fv/Fm) and the carbon dioxide (CO2) tropospheric concentration, together with eddy covariance measurements of CO2 flux. We used CO2 flux data from four boreal coniferous forest sites covering a wide latitudinal range, and CO2 concentration measurements from Sammaltunturi in Pallas. The CO2 gas exchange was taken as the primary determinant for the growing season to which other methods were compared. Indices based on the cumulative temperature sum and the variation in daily mean temperature were successfully used for approximating the start and cessation of the growing season. The beginning of snow melt was a successful predictor of the onset of the growing season. The chlorophyll fluorescence parameter Fv/Fm and the CO2 concentration were good indicators of both the commencement and cessation of the growing season. By a derivative estimation method for the CO2 concentration, we were also able to capture the larger-scale spring recovery. The trends of the CO2 concentration and temperature indices at Pallas/Sammaltunturi were studied over an 11-yr time period, and a significant tendency towards an earlier spring was observed. This tendency was not observed at the other sites. [ABSTRACT FROM AUTHOR]

The seasonality of the NEE of the northern boreal coniferous forests was investigated by means of inversion modelling using eddy covariance data. Eddy covariance data was used to optimize the biochemical model parameters. Our study sites consisted of three Scots pine (l. Pinus sylvestris) forests and one Norway spruce (l. Picea abies) forest that were located in Finland and Sweden. We obtained temperature and seasonal dependence for the biochemical model parameters: the maximum rate of carboxylation (Vc(max)) and the maximum rate of electron transport (Jmax). Both of the parameters were optimized without assumptions about their mutual magnitude. The values obtained for the biochemical model parameters were similar at all the sites during summer time. To describe seasonality, different temperature fits were made for the spring, summer and autumn periods. During summer, average Jmax across the sites was 54.0 μmolm-2 s-1 (variance 31.2 μmolm-2 s-1) and Vc(max) was 12.0 μmolm-2 s-1 (variance 6.6 μmolm-2 s-1) at 17°C. The sensitivity of the model to LAI and atmospheric soil water stress was also studied. The impact of seasonality on annual GPP was 17% when only summertime parameterization was used throughout the year compared to seasonally changing parameterizations. [ABSTRACT FROM AUTHOR]

The biochemical seasonality of the northern boreal coniferous forests was investigated by means of inversion modelling using eddy covariance data. Eddy covariance data was used to optimize the biochemical model parameters. Our study sites consisted of three Scots pine (l. Pinus sylvestris) forests and one Norway spruce (l. Picea abies) forest that were located in Finland and Sweden. We obtained temperature and seasonal dependence for the biochemical model parameters: the maximum rate of carboxylation (Vc(max)) and the maximum rate of electron transport (Jmax). Both of the parameters were optimized without assumptions about their mutual magnitude. The values obtained for the biochemical model parameters were similar at all the sites during summer time. To describe seasonality, different temperature fits were made for the spring, summer and autumn periods. During summer, average Jmax across the sites was 54.0 μmol m-2 s-1 (variance 31.2 μmol m-2 s-1) and Vc(max) was 12.0 μmol m-2 s-1 (variance 6.6 μmol m-2 s-1) at 17°C. The sensitivity of the model to LAI was also studied. Simulation runs were done to study the effect of the seasonality implemented in the model using different temperature fits. The impact of seasonality on annual GPP was 15%, which corresponded to an increase of 2°C in air temperature. [ABSTRACT FROM AUTHOR]

CO2 fluxes and concentrations were simulated in the planetary boundary layer above subarctic hilly terrain using a three dimensional model. The model solves the transport equations in the local scale and includes a vegetation sub-model. A WMO/GAW background concentration measurement site and an ecosystem flux measurement site are located inside the modeled region at a hilltop and above a mixed boreal forest, respectively. According to model results, the concentration measurement at the hill site was representative for continental background. However, this was not the case for the whole model domain. Concentration at few meters above active vegetation represented mainly local variation. Local variation became inseparable from the regional signal at about 60-100m above ground. Flow over hills changed profiles of environmental variables and height of inversion layer, however CO2 profiles were more affected by upwind land use than topography. The hill site was above boundary layer during night and inside boundary layer during daytime. The CO2 input from model lateral boundaries dominated in both cases. Daily variation in the CO2 assimilation rate was clearly seen in the CO2 profiles. Concentration difference between the hill site and the forest site was about 5 ppm during afternoon according to both model and measurements. The average modeled flux to the whole model region was about 40% of measured and modeled local flux at the forest site. [ABSTRACT FROM AUTHOR]

CO2 fluxes and concentrations were simulated in the planetary boundary layer above subarctic hilly terrain using a three dimensional model. The model solves the transport equations in the local scale and includes a vegetation sub-model. A WMO/GAW background concentration measurement site and an ecosystem flux measurement site are located inside the modeled region at a hilltop and above a mixed boreal forest, respectively. According to model results, the concentration measurement at the hill site was representative for continental background. However, this was not the case for the whole model domain. Concentration at few meters above active vegetation represented mainly local variation. Local variation became inseparable from the regional signal at about 60-100m above ground. Flow over hills changed profiles of environmental variables and height of inversion layer, however CO2 profiles were more affected by upwind land use than topography. The hill site was above boundary layer during night and inside boundary layer during daytime. The CO2 input from model lateral boundaries dominated in both cases. Daily variation in the CO2 assimilation rate was clearly seen in the CO2 profiles. Concentration difference between the hill site and the forest site was about 5 ppm during afternoon according to both model and measurements. The average modeled flux to the whole model region was about 40% of measured and modeled local flux at the forest site. [ABSTRACT FROM AUTHOR]

1. Primary cultures of cardiomyocytes provide a valuable tool for the study of the pharmacological and toxicological properties of drugs and chemicals, but for several technical reasons cardiomyocytes from adult animals are not routinely used in long-term culture. Because of significant advances in cardiovascular research, tissue engineering and cell transplantation, the need to isolate primary cells from adult animal and/or human tissue is likely to increase in the future. 2. The most common protocols for the isolation and cultivation of cardiomyocytes have been reviewed and the various approaches have been compared. The recent advances in cell culture techniques and the use of the cytoprotective agent, e.g. 2,3-butanedione monoxime greatly increases cell yield and cell viability of isolated and cultured cardiomyocytes. New concepts emerge that enabled an assessment of cellular differentiation in cultured cardiomyocytes and certain specific nuclear transcription factors may play a pivotal role in this process. [ABSTRACT FROM AUTHOR]

In response to myocardial infarction (MI), extracellular vesicles (EVs), including large (lEVs) and small (sEVs), are released within and from the heart to facilitate intercellular communication and maintain cardiac homeostasis by transporting cargo to recipient cells. We investigated how glucose intolerance influences the intracardiac EV release post-MI and their content. B6J mice were fed chow (CD) or high-fat diet (HFD) for 3 months. MI was induced by permanent coronary artery ligation. EVs were isolated from left ventricles and quantified by tunable resistive pulse sensing. EVs were characterised by flow cytometry. EV miRNA content was determined by RNAseq and qPCR. Using cardiomyocyte specific GFP+ mice, plasma lEVs were analysed by flow cytometry to determine if cardiomyocyte EVs (CMEVs) are circulating. Labelled hypoxic cardiomyocyte cell line (HL-1) lEVs were injected in HFD/CD mice post-MI to determine target cells. In CD mice, EV release was significantly increased 24 h post-MI compared to sham. HFD lEV levels were significantly higher compared to sham and CD mice post-MI with no difference in sEV release between sham and MI HFD mice. Intracardiac lEVs originate from cardiomyocyte and endothelial cells in response to MI and MI + HFD respectively. qPCR analyses identified miRNA candidates that were modulated by MI and HFD. Intracardiac GFP + lEV levels were lower in HFD than in CD mice whereas levels of circulating GFP + lEVs were higher. In vivo biodistribution studies revealed a preferential uptake of hypoxic HL-1 lEVs by splenic myeloid cells in HFD spleens versus CD post-MI. Our results show that glucose intolerance modulates intracardiac EV release post-MI and their miRNA cargo. Circulating CMEV levels as well as their uptake by splenic myeloid cells are increased. Further investigations will aim to decipher the impact of the intracardiac EV miRNA mediated transfer in the diabetic heart post-MI. [ABSTRACT FROM AUTHOR]

Ex vivo multicellular preparations are essential tools to study tissue physiology. Among them, the recent methodological and technological developments in living myocardial slices (LMS) are attracting increasing interest by the cardiac research field. Despite this, this research model remains poorly perceived and utilized by most research laboratories. Here, we provide a practical guide on how to use LMS to interrogate multiple aspects of cardiac function, structure and biochemistry. We discuss issues that should be considered to conduct successful experiments, including experimental design, sample preparation, data collection and analysis. We describe how laboratory setups can be adapted to accommodate and interrogate this multicellular research model. These adaptations can often be achieved at a reasonable cost with off-the-shelf components and operated reliably using well-established protocols and freely available software, which is essential to broaden the utilization of this method. We will also highlight how current measurements can be improved to further enhance data quality and reliability to ensure inter-laboratory reproducibility. Finally, we summarize the most promising biomedical applications and envision how living myocardial slices can lead to further breakthroughs. [ABSTRACT FROM AUTHOR]