Display omitted
Over the last decade, laboratory experiments have revealed a wide range of adverse effects in marine organisms following exposure to microplastics. This study investigated the working ...hypothesis that the observed effects of two types of virgin micro polymers ((polystyrene (PS) and high density polyethylene (HDPE)) might be, at least in part, due to the leaching of co-contaminants. For this purpose, the toxicity of these two polymeric materials and their leachates was tested on gametes and zygotes of the sea urchin Paracentrotus lividus following validated procedures. Zygotes were exposed for 48 hours to virgin and aged microspheres and leachates of fluorescent PS (10^3, 10^4 and 10^5 particles/mL) and agranular HDPE fluff (0.005, 0.5 and 5 g/L). Additionally, sea urchin eggs were exposed for 10 minutes to virgin fluorescent PS microspheres (10^3, 10^4 and 10^5 particles/mL). After exposure, the fertilization rate and percentage of larval abnormalities as well as larval growth were determined and compared to control groups. Overall, toxic effects on embryonic development and larval growth of the sea urchin were found for all treatments (untreated and weathered particles and leachates) with both polymeric materials. Furthermore, the highest toxicity (% abnormalities and reduction of the larval growth > 50%) was found after exposure to the lowest concentrations of leachate solutions for both types of polymeric materials. Microplastic ingestion was observed in the gastric cavity of the larvae in a dose- dependent manner, but not in a toxicity-dependent manner. Furthermore, eggs pre-exposed to concentrations of PS microspheres (10^3, 10^4 and 10^5 particles/mL) showed a toxic effect on the fertilization rate and on subsequent larval development as well as growth in a dose-dependent manner. These findings demonstrate that virgin microplastics are toxic to sea urchins through the leaching of chemicals, e.g., additives, residual monomers and other co-contaminants, which has been confirmed by chemical analysis elsewhere. The results of this study highlight the necessity to wash or weather microplastics before they are used in experimental laboratory studies to allow a more realistic extrapolation of the results to field conditions.
•Toxicity of virgin PS and HDPE particles and their leachates was investigated.•Virgin microplastics are toxic to sea urchin embryo through the leaching of chemicals.•Our results highlight the necessity to wash or weather virgin microplastics before toxicity testing.
ATM-mediated signaling in response to DNA damage is a barrier to tumorigenesis. Here we asked whether replication stress could also contribute to ATM signaling. We demonstrate that, in the absence of ...DNA damage, ATM responds to replication stress in a hypoxia-induced heterochromatin-like context. In certain hypoxic conditions, replication stress occurs in the absence of detectable DNA damage. Hypoxia also induces H3K9me3, a histone modification associated with gene repression and heterochromatin. Hypoxia-induced replication stress together with increased H3K9me3 leads to ATM activation. Importantly, ATM prevents the accumulation of DNA damage in hypoxia. Most significantly, we describe a stress-specific role for ATM in maintaining DNA replication rates in a background of increased H3K9me3. Furthermore, the ATM-mediated response to oncogene-induced replication stress is enhanced in hypoxic conditions. Together, these data indicate that hypoxia plays a critical role in the activation of the DNA damage response, therefore contributing to this barrier to tumorigenesis.
•In the absence of damage, ATM responds to replication stress in H3K9me3-rich contexts•The levels of ATM-S1981, H3K9me3, and hypoxia correlate well in vivo•ATM maintains DNA replication rates in hypoxia•ATM prevents the accumulation of DNA damage in hypoxic conditions
Regions of hypoxia occur in most solid tumors, and they are associated with a poor prognostic outcome. Despite the absence of detectable DNA damage, severe hypoxia (<0.1% O2) induces a DNA damage ...response, including the activation of p53 and subsequent induction of p53-dependent apoptosis. Factors affecting hypoxia-induced p53-dependent apoptosis are unclear. Here we asked whether H3K9me3, through mediating gene repression, could regulate hypoxia-induced p53-dependent apoptosis. Under hypoxic conditions, increases in H3K9me3 occur in an oxygen-dependent but HIF-1-independent manner. We demonstrate that under hypoxic conditions, which induce p53 activity, the negative regulator of p53, APAK, is repressed by increases in H3K9me3 along the APAK loci. APAK repression in hypoxia is mediated by the methyltransferase SETDB1 but not Suv39h1 or G9a. Interestingly, increasing hypoxia-induced H3K9me3 through pharmacological inhibition of JMJD2 family members leads to an increase in apoptosis and decreased clonogenic survival and again correlates with APAK expression. The relevance of understanding the mechanisms of APAK expression regulation to human disease was suggested by analysis of patients with colorectal cancer, which demonstrates that high APAK expression correlates with poor prognosis. Together, these data demonstrate the functional importance of H3K9me3 in hypoxia, and they provide a novel mechanistic link between H3K9me3, p53 and apoptosis in physiologically relevant conditions of hypoxia.
Hypoxia (low oxygen) is a common feature of solid tumors that has been intensely studied for more than six decades. Here we review the importance of hypoxia to radiotherapy with a particular focus on ...the contribution of hypoxia to immune responses, metastatic potential and FLASH radiotherapy, active areas of research by leading women in the field.
Although hypoxia-driven metastasis and immunosuppression can negatively impact clinical outcome, understanding these processes can also provide tumor-specific vulnerabilities that may be therapeutically exploited. The different oxygen tensions present in tumors and normal tissues may underpin the beneficial FLASH sparing effect seen in normal tissue and represents a perfect example of advances in the field that can leverage tumor hypoxia to improve future radiotherapy treatments.
Nowadays, Ethiopia has several problems affecting children below 5 years of age, resulting in low life expectancies. Our group carried out a study to calculate the presence of malnutrition as ...wasting, stunting underweight, and BMI-for-age in children presenting in a nutrition center in a rural Ethiopian village in the Oromia region according to WHO guidelines. Our results demonstrated that they had moderate chronic malnutrition or stunting from 1 to 2 years of age, affecting their life, their parents, their community/household, and their country. In our viewpoint, the solution for this situation will require a global focus on several levels, including individual, family, community, and country, the last being with the help of new health policies focused on short-, medium-, and long-term strategies with multi- and interdisciplinary approaches.
This interdisciplinary dialogue draws on climatology and cultural studies to explore the phenomenon of “Saharan dust” that passes through and beyond the Spanish Mediterranean Basin. The dialogic ...process seeks to unearth the power relations within which weather stories and the authors are always already entangled, with a view to re-imagining weather writing and climatic storytelling in decolonial terms. Our parallel inquiries trace how origin stories, material mobilities, atmospheres, and environmental regulation work to codify the aeolian dust as an intrusion across borders. Drawing on critical theory, we argue that this weather “from” the Sahara Desert is othered in Eurocentric weather narratives, mapping onto geopolitical logic of “Fortress Europe”. Our research is instructed by postcolonial thought, political ecology, and the speculative feminist position of weathering. Through critical engagement with science in context, we dwell lastly on African air quality and experiences of weathering atmospheric dust further upwind. Our concluding comments speculatively drift with Mediterranean winds to animate a positionality of middleness.
The term hypoxia refers to any condition where insufficient oxygen is available and therefore encompasses a range of actual oxygen concentrations. The regions of tumours adjacent to necrotic areas ...are at almost anoxic levels and are known to be extremely therapy resistant (radiobiological hypoxia). The biological response to radiobiological hypoxia includes the rapid accumulation of replication stress and subsequent DNA damage response, including both ATR‐ and ATM‐mediated signalling, despite the absence of detectable DNA damage. The causes and consequences of hypoxia‐induced replication stress will be discussed.
Ribonucleotide reductase (RNR) is a key enzyme required for the synthesis of nucleotides for subsequent incorporation into DNA. In hypoxic (low oxygen) conditions, the composition of RNR is altered to include a stress specific subunit, RRM2B. RRM2B is adapted to function in hypoxic conditions and therefore continue the synthesis of nucleotides.
Trust and punishment Olcina, Gonzalo; Calabuig, Vicente
European Journal of Political Economy,
December 2021, 2021-12-00, 20211201, Letnik:
70
Journal Article
Recenzirano
This paper explores the impact of institutions on the evolution of preferences (culture) and on economic outcomes. Punishment institutions determine the capacity and the individual cost of punishing ...opportunistic behavior, while preferences are endogenous and can be influenced by a cultural transmission process that is conditioned by the existing punishment institutions. We investigate the interaction and evolution between the preferences for reciprocity or rewarding of the allocator and the preferences to punish hostile behaviour by the investor in a trust game with a costly punishment phase. Our main result provides a rationale for the existence of a strong positive relationship between the quality of society's punishment institutions and the levels of trust achieved. Trust only flourishes in the shadow of efficient sanctioning institutions. The driving force behind this result is that strong institutions are necessary to make the socialization of children towards punishment preferences worthwhile. However, there is no relationship between the level of trust and the distribution of social preferences. Even when there is a high proportion of punishers in the population, a high level of trust will not be obtained if there is not a well-functioning punishment institution.
•Institutions determine the capacity and the individual cost of punishment.•Punishment institutions require individuals with preferences for negative reciprocity.•Punishment institutions incentivize socialization on negative reciprocity preferences.•High levels of trust are achieved only under strong punishment institutions.•There is no relationship between the preference distribution and the levels of trust.
As the world intensifies its efforts to reduce the adverse effects of global warming, the shift towards a fully developed hydrogen-based economy is emerging as a core strategy. This transition ...involves the strategic blending of hydrogen with conventional fossil fuels such as natural gas (HCNG), allowing for adaptation to hydrogen availability. Nevertheless, the environmental impact of HCNG vehicles in realistic scenarios with variable hydrogen content remains unexplored. This study focuses on evaluating the global warming impact of the transition of light-duty passenger cars from CNG to H2 vehicles using HCNG blends from 2020 to 2050 and different realistic scenarios. The results in the present study were obtained through a combination of an experimental testing campaign that allowed obtaining how the performance and emissions of HCNG vehicles change with the H2 content and a life cycle assessment methodology. Based on the findings, the scenario in which hydrogen was mostly produced from SMR-dominant, was found to have the potential to reach and outperform the zero-emission concept due to the utilization of biogas. From the results of this study, the recommended H2 content in HCNG blends that offers low environmental impact while avoiding the overdemand of hydrogen in the short term for the 2020–2030 decade is 25% H2 content, increasing to 50% by 2030, and to 75%–100% during the 2040–2050 decade, thus reaching the transition towards pure-H2 technology that minimizes environmental impact.
•Cradle-to-grave GHG emissions for HCNG vehicle transition to H2 were estimated.•The electricity, H2 and natural gas mix evolution in 2020–2050 were considered.•The impact of biogas fraction in the natural gas mix was accounted for.•The optimal evolution of H2 content on the HCNG blends was devised.•Zero cradle-to-grave emissions are achievable in 2050 with at least 50% of H2 content.
The current fast-moving, hectic lifestyle has increased the number of individuals worldwide with difficulties in managing stress, which in turn is also affecting their sleep quality. Therefore, the ...objective of the current study was to assess a natural plant-based dietary supplement comprised of lemon verbena (
) extract, purified in phenylpropanoids, in alleviating stress and improving quality of sleep. A double-blind, placebo-controlled study was conducted for 8 weeks, followed by a 4-week washout period. Both validated questionnaires and functional tests were performed during the study, whereas questionnaires were used after the washout. As a result, the group taking the lemon verbena extract significantly reduced their perception of stress after 8 weeks, which was corroborated by a significant decrease in cortisol levels. After the washout period, the subjects reported to present even lower stress levels, due to the lasting effect of the ingredient. As for sleep quality, the subjects taking the supplement reported feeling better rested, with a stronger effect observed in women. Sleep tracking using a wearable device revealed that the supplement users improved their times in the deeper stages of sleep, specifically their percentage of time in deep sleep and REM. In conclusion, lemon verbena extract purified in phenylpropanoids is revealed as a natural solution to help individuals to improve their stress and sleep quality.
PDF
