An evaluation of the tourism-induced environmental Kuznets curve (T-EKC) hypothesis: Evidence from G7 countries

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This paper analyzes the legitimacy of the Environmental Kuznets Curve (EKC) hypothesis for a group of seven (G7) countries over the period 1995–2015. In addition to testing the EKC speculation, the authors also would like to understand the ways in which increases in renewable energy consumption and the international tourism receipt affect the CO2 emissions in G7 countries, because the energy and tourism sectors may have considerable direct impacts on CO2 emissions. In this investigation, a panel bootstrap cointegration test and an augmented mean group (AMG) estimator were applied. The empirical findings indicate that the tourism-induced EKC hypothesis is valid only for France. Additionally, it was detected that a rise in renewable energy consumption has a negative (reduction) impact on CO2 emissions in France, Italy, the UK, and the US. However, an increase in the receipt of international touristm has a positive (additional) impact on Italy’s CO2 emissions. Hence, this country’s decision-makers should re-review their tourism policy to adopt a renewable-inclusive one for sustainable tourism and the environment

A proteomics analysis of 5xFAD mouse brain regions reveals the lysosome-associated protein Arl8b as a candidate biomarker for Alzheimer's disease

BACKGROUND: Alzheimer's disease (AD) is characterized by the intra- and extracellular accumulation of amyloid-β (Aβ) peptides. How Aβ aggregates perturb the proteome in brains of patients and AD transgenic mouse models, remains largely unclear. State-of-the-art mass spectrometry (MS) methods can comprehensively detect proteomic alterations, providing relevant insights unobtainable with transcriptomics investigations. Analyses of the relationship between progressive Aβ aggregation and protein abundance changes in brains of 5xFAD transgenic mice have not been reported previously. METHODS: We quantified progressive Aβ aggregation in hippocampus and cortex of 5xFAD mice and controls with immunohistochemistry and membrane filter assays. Protein changes in different mouse tissues were analyzed by MS-based proteomics using label-free quantification; resulting MS data were processed using an established pipeline. Results were contrasted with existing proteomic data sets from postmortem AD patient brains. Finally, abundance changes in the candidate marker Arl8b were validated in cerebrospinal fluid (CSF) from AD patients and controls using ELISAs. RESULTS: Experiments revealed faster accumulation of Aβ42 peptides in hippocampus than in cortex of 5xFAD mice, with more protein abundance changes in hippocampus, indicating that Aβ42 aggregate deposition is associated with brain region-specific proteome perturbations. Generating time-resolved data sets, we defined Aβ aggregate-correlated and anticorrelated proteome changes, a fraction of which was conserved in postmortem AD patient brain tissue, suggesting that proteome changes in 5xFAD mice mimic disease-relevant changes in human AD. We detected a positive correlation between Aβ42 aggregate deposition in the hippocampus of 5xFAD mice and the abundance of the lysosome-associated small GTPase Arl8b, which accumulated together with axonal lysosomal membranes in close proximity of extracellular Aβ plaques in 5xFAD brains. Abnormal aggregation of Arl8b was observed in human AD brain tissue. Arl8b protein levels were significantly increased in CSF of AD patients. CONCLUSIONS: We report a comprehensive biochemical and proteomic investigation of hippocampal and cortical brain tissue derived from 5xFAD transgenic mice, providing a valuable resource to the neuroscientific community. We identified Arl8b, with significant abundance changes in 5xFAD and AD patient brains. Arl8b might enable the measurement of progressive lysosome accumulation in AD patients and have clinical utility as a candidate biomarker

A proteomics analysis of 5xFAD mouse brain regions reveals the lysosome-associated protein Arl8b as a candidate biomarker for Alzheimer’s disease

BACKGROUND: Alzheimer's disease (AD) is characterized by the intra- and extracellular accumulation of amyloid-ß (Aß) peptides. How Aß aggregates perturb the proteome in brains of patients and AD transgenic mouse models, remains largely unclear. State-of-the-art mass spectrometry (MS) methods can comprehensively detect proteomic alterations, providing relevant insights unobtainable with transcriptomics investigations. Analyses of the relationship between progressive Aß aggregation and protein abundance changes in brains of 5xFAD transgenic mice have not been reported previously. METHODS: We quantified progressive Aß aggregation in hippocampus and cortex of 5xFAD mice and controls with immunohistochemistry and membrane filter assays. Protein changes in different mouse tissues were analyzed by MS-based proteomics using label-free quantification; resulting MS data were processed using an established pipeline. Results were contrasted with existing proteomic data sets from postmortem AD patient brains. Finally, abundance changes in the candidate marker Arl8b were validated in cerebrospinal fluid (CSF) from AD patients and controls using ELISAs. RESULTS: Experiments revealed faster accumulation of Aß42 peptides in hippocampus than in cortex of 5xFAD mice, with more protein abundance changes in hippocampus, indicating that Aß42 aggregate deposition is associated with brain region-specific proteome perturbations. Generating time-resolved data sets, we defined Aß aggregate-correlated and anticorrelated proteome changes, a fraction of which was conserved in postmortem AD patient brain tissue, suggesting that proteome changes in 5xFAD mice mimic disease-relevant changes in human AD. We detected a positive correlation between Aß42 aggregate deposition in the hippocampus of 5xFAD mice and the abundance of the lysosome-associated small GTPase Arl8b, which accumulated together with axonal lysosomal membranes in close proximity of extracellular Aß plaques in 5xFAD brains. Abnormal aggregation of Arl8b was observed in human AD brain tissue. Arl8b protein levels were significantly increased in CSF of AD patients. CONCLUSIONS: We report a comprehensive biochemical and proteomic investigation of hippocampal and cortical brain tissue derived from 5xFAD transgenic mice, providing a valuable resource to the neuroscientific community. We identified Arl8b, with significant abundance changes in 5xFAD and AD patient brains. Arl8b might enable the measurement of progressive lysosome accumulation in AD patients and have clinical utility as a candidate biomarker

Diatom Thalassiosira weissflogii in oligotrophic versus eutrophic culture: models and ultrastructure

7 páginas, 1 tabla, 1 figuraPopulations of marine diatom Thalassiosira weissflogii were grown in continuous cultures enriched with f/2 medium. One of the two contrasting cultures (‘eutrophic’) received 5.6 times more nutrients than the other (‘oligotrophic’). Two mathematical models are analyzed to estimate eutrophication differences. The second model based on the Michaelis–Menten uptake and Droop growth shows that cells in the eutrophic culture should have about 56% higher content of silica which is the limiting nutrient. Diatom samples were prepared for the transmission electron microscopy after cells have been kept in chemostats for 37 days. The structure of diatom cells was investigated and a comparison is made between cells grown in oligotrophic and eutrophic conditions. In eutrophic culture, dividing cells were encountered more frequently while cell concentration was approximately equal in both chemostats. The central vacuole of cells in eutrophic culture accumulated dispersed and compact material from amorphous to spherical shape. In some cells the large central vacuole had fibrilar and peppered dense materials in addition to translucent granules, vesicules and multivesicular bodies. In the cytoplasm we found increased number of multivesicular bodies, dense and lucent granules some of which enclose membrane particles and lucent vesicules. Dense material depositions observed in the vacuole are also seen in the cytoplasm associated with organelles, mitochondria and plasmalemma. Cells have well-developed, active and slightly increased number of dictyosomes (5–6). Some dictyosomes with dense secretory material in the cistern are apparently engaged in a granule formation process. Functional significance of dense material in the central vacuole, which has not been observed in cells grown in oligotrophic condition, is discussed.Peer reviewe

Correlation of ADC values measured using 3T diffusion-weighted MRI and SUVs from fluorodeoxyglucose PET/CT in head and neck squamous cell carcinomas

Aims: The aim of our study was to assess the correlations between apparent diffusion coefficient (ADC) values and standardized uptake values (SUVs) and their correlations with tumor size, tumor stage and histological grade in patients with head and neck squamous cell carcinomas (HNSSCs). Methods: This retrospective study included 36 patients with histologically confirmed HNSSCs visible on diffusion weighted imaging (DWI) and fluorodeoxyglucose (FDG) positron emission tomography (PET/CT). Correlations of minimum ADC (ADCmin), mean ADC (ADCmean), and minimum-mean ADC ratio (ADCmin/mean) with maximum SUV (SUVmax) and lean body mass SUVlbm (SUVlbm) were analyzed using the Spearman's correlation test. The Kruskal-Wallis one-way ANOVA test and Mann-Whitney U test were used to assess the correlations of ADC values and SUVs with tumor size, tumor stage and histological grade. Two experienced readers measured the ADC and SUVs independently, and intraclass correlation coefficient (ICC) was used to analyze the inter-observer agreement. Results: The mean ADCmin, ADCmean, and ADCmin/mean for HNSSCs were 0.68±0.17x10-3 mm2/s, 0.82±0.17x10-3 mm2/s, and 0.83±0.10, respectively. The mean SUVmax and SUVlbm were 14.65±5.5 and 10.96±5.1, respectively. The correlations between ADC values and SUVs did not reach statistical significance. There were no significant correlations of ADC values and SUVs with tumor size, tumor stage or histological grade. There was a tendency of SUVs to increase and ADC values to decrease with tumor dedifferentiation; however, the changes were not significant. Inter-observer agreement for tumor ADC values and SUVs was almost perfect (ICC>0.81). Conclusions: Pretreatment ADC values and SUVs in HNSSCs are reproducible and independent biomarkers. © 2020 Galenos Publishing House.received no financial support