Effects Of Long-term Exposure Research Articles

Assessment of sub-lethal effects of Celcron on Java barb through erythrocyte morphology and acetylcholinesterase activity: Implications for environmental health in aquatic ecosystems

Industrialization and the extensive use of chemicals have raised significant concerns about their environmental impacts, particularly on aquatic ecosystems. This study evaluated the sub-lethal effects of Celcron (Cec), an organophosphate insecticide, on the Java barb (Barbonymus gonionotus) through erythrocyte morphology and acetylcholinesterase (AChE) activity, aiming to refine biomarkers for environmental health assessments. We hypothesized that sub-lethal Cec exposure would induce significant erythrocyte abnormalities and decrease AChE activity in Java barb, with variable recovery rates between gill and kidney tissues. To test this, we exposed the juvenile Java barbs to two sub-lethal Cec concentrations - 0.01 ppm (10 % of the LC50) and 0.05 ppm (50 % of the LC50) -for 60 days. After the exposure period, the fish were placed in pesticide-free water to allow for recovery. Results indicated a significant decline in AChE activity in both liver and kidney tissues, with activity levels showing gradual recovery over time. Erythrocyte abnormalities, including nuclear and cellular changes, were significantly elevated in response to Cec exposure. The frequency of nuclear abnormalities such as micronuclei and binucleation increased in a concentration- and duration-dependent manner, with the gill blood exhibiting higher sensitivity and slower recovery compared to kidney blood. Cellular abnormalities such as twin, teardrop and spindle-shaped cells were also more prevalent in Cec-treated fish. Recovery from these abnormalities was observed but varied between gill and kidney blood, with gill blood showing higher sensitivity and slower recovery compared to kidney blood. This study underscores the utility of AChE activity and erythrocyte abnormalities as biomarkers for assessing pesticide impacts on aquatic organisms. The findings highlight the sensitivity of fish erythrocytes to environmental contaminants and emphasize the need for continued research to better understand the long-term effects of pesticide exposure on aquatic health and ecosystem stability.

Neonatal Cannabidiol Exposure Impairs Spatial Memory and Disrupts Neuronal Dendritic Morphology in Young Adult Rats.

Introduction: Early life is a sensitive period for brain development. Perinatal exposure to cannabis is increasingly linked to disruption of neurodevelopment; however, research on the effects of cannabidiol (CBD) on the developing brain is scarce. In this study, we aim to study the developmental effects of neonatal CBD exposure on behavior and dendritic architecture in young adult rats. Materials and Methods: Male and female neonatal Sprague Dawley rats were treated with CBD (50 mg/kg) intraperitoneally on postnatal day (PND) 1, 3, and 5 and evaluated for behavioral and neuronal morphological changes during early adulthood. Rats were subjected to a series of behavioral tasks to evaluate long-term effects of neonatal CBD exposure, including the Barnes maze, open field, and elevated plus maze paradigms to assess spatial memory and anxiety-like behavior. Following behavioral evaluation, animals were sacrificed, and neuronal morphology of the cortex and hippocampus was assessed using Golgi-Cox (GC) staining. Results: Rats treated with CBD displayed a sexually dimorphic response in spatial memory, with CBD-treated females developing a deficit but not males. CBD did not elicit alterations in anxiety-like behavior in either sex. Neonatal CBD caused an overall decrease in dendritic length and spine density (apical and basal) in cortical and hippocampal neurons in both sexes. Sholl analysis also revealed a decrease in dendritic intersections in the cortex and hippocampus, indicating reduced dendritic arborization. Conclusions: This study provides evidence that neonatal CBD exposure perturbs normal brain development and leads to lasting alterations in spatial memory and neuronal dendrite morphology in early adulthood, with sex-dependent sensitivity.

Integrated Biomarker Response Emphasizing Neuronal Oxidative Stress and Genotoxicity Induced by Oxamyl in Sprague Dawley Rats: Ameliorative Effect of Ginseng as a Neuroprotective Agent

Climate change has led to increased and varying pest infestation patterns, triggering a rise in pesticide usage and exposure. The effects of oxamyl, a widely used nematicide in Egypt, encompasses typical signs of carbamate intoxication; nevertheless, long-term effects of oxamyl exposure, particularly on the nervous system, require further elucidation. This study systematically investigated the mechanism and manifestations of repeated subacute exposure to sublethal doses of oxamyl in male SD rats. Data showed a dose-dependent genotoxic effect, manifested as increased bone marrow micronuclei and decreased brain expression of key genes involved in neurogenesis and neuronal development. Coincidently, brain histopathology showed dose-dependent neurodegeneration in various regions, associated with a significant increase in GFAP immunoreactivity, indicative of neuroinflammation. Biochemical examination revealed a typical pattern of cholinesterase inhibition by carbamates in serum and brain tissue, as well as increased oxidative stress markers in the brain such as SOD activity reduction, alongside an increase in NO and MDA. The ability of Ginseng at a 100 mg/Kg dose to ameliorate the effects of oxamyl exposure was investigated. Ginseng use, either as a protective or therapeutic regimen, attenuated the observed genotoxic, neuroinflammatory, and biochemical alterations. Our results indicate that repeated exposure to oxamyl triggers an integrative neurotoxic response, driven by genotoxicity, oxidative stress, and neuroinflammation, that could trigger an increase in neurological and cognitive disorders. These findings emphasize the urgent need for confirmatory translational studies in human subjects to assess these changes and inform policy decisions regarding safe levels of usage and appropriate agricultural and public health practices.

Characterization of Wear Patterns in Gun Barrel’s Throat Region Using Forensic Microscope: Insights Into Long-Term Effects of High-Pressure Gas Exposure

Objectives: This research aims to explore the damage sustained by the gun barrel's throat region over a long period of use, shedding light on the wear characteristics, and providing valuable insights into the long-term effects of high-pressure gas exposure during firing. Methods: To achieve this objective, the appearance of the gun barrel's throat region was characterized using forensic microscopy techniques. Visual and microscopic examinations were conducted on five (5) gun barrels with ten years or less of service usage and five (5) gun barrels with over ten years of service usage from the Philippine National Police to assess the degree of wear in the barrel’s throat region. Findings: The findings revealed varying degrees of wear in the barrel throat regions. Firearms with 10 years or less of service usage exhibited moderate corrosion, narrow cracks, and minimal soot particle presence while firearms with over 10 years of service usage showed severe corrosion, deep cracks, scattered potholes, superficial scraped surfaces, and heavy soot particle presence. Novelty: This research contributes to the understanding of barrel performance, maintenance, and potential hazards associated with aging firearms, thus providing novel insights into the long-term effects of high-pressure gas exposure during firing. By examining the changes in material properties and surface roughness of the gun barrel’s throat region, this study seeks to improve the understanding of how repeated firing impacts gun barrel performance and longevity. This, in turn, may aid in developing future maintenance practices to enhance firearm durability and safety. Keywords: Gun Barrels, Wear Characteristics, Gun Barrel Throat Region, High-Pressure Gas Exposure, Wear Patterns

Association between long-term PM1 exposure and cognition in middle-aged and older adults: Evidence from China and the United Kingdom

Early risk detection and management are essential for cognitive preservation. While particulate matters of diameter small than 2.5 μm (PM2.5) is considered harmful to cognition, the effect of smaller, more penetrative particulate matters of diameter small than 1 μm (PM1) requires further evidence and explicit safety thresholds. In this study, we explored the effects of long-term PM1 exposure on early cognitive impairment and longitudinal cognitive changes in middle-aged and older populations. This study assessed data from two large-scale longitudinal surveys: the China Health and Retirement Longitudinal Study (CHARLS) and UK Biobank (UKB). Cross-sectional, longitudinal, and trajectory analyses were conducted to investigate the association between long-term PM1 exposure and cognition. Additionally, the exposure–response curves were fitted to determine the customized thresholds. The findings indicated that sustained PM1 exposure may lead to mild cognitive impairment, particularly at concentrations exceeding 30 and 5.6 μg·m−3 in CHARLS and UKB participants, respectively. Furthermore, we found that long-term PM1 exposure can contribute to rapid cognitive decline at concentrations exceeding 23 and 5.5 μg·m−3 in CHARLS and UKB participants, respectively. In conclusion, reducing PM1 exposure can improve the cognitive health of middle-aged and older adults.

Influence of Combat Experience on Psychophysiological and Fine Motor Skill Responses in Air Force Warfighters under Acute Stress

This study investigates the influence of experience on stress responses and fine motor skills among professional male military parachutists. We analyzed 132 paratroopers, divided into a non-experienced group (NEG; ≤6 parachute jumps) and an experienced group (EG; >50 jumps). Baseline samples were collected 2.5 hours before participants performed a 500 m jump, with post-jump evaluations conducted immediately after landing. Results indicated that experience significantly influences fine motor skills and stress responses. Non-experienced jumpers showed greater degradation in fine motor skills and higher cortical arousal pre-jump levels, suggesting an increased anticipatory state. In contrast, experienced parachutists maintained more consistent fine motor skills and exhibited a ceiling effect in stress response. Leg strength was higher in non-experienced jumpers, reflecting youth and greater muscle mass, with no significant difference in hand strength. These findings highlight the role of experience in managing stress and maintaining motor skills under pressure. The study suggests further exploration into psychological aspects like motivation and resilience, along with the long-term effects of stress exposure. The importance of experience in high-stress military operations emphasizes the need for targeted training interventions to enhance stress-coping mechanisms in less experienced individuals.

Both Maternal High-Fat and Post-Weaning High-Carbohydrate Diets Increase Rates of Spontaneous Hepatocellular Carcinoma in Aged-Mouse Offspring.

Both maternal obesity and postnatal consumption of obesogenic diets contribute to the development of metabolic dysfunction-associated steatotic liver disease (MASLD) and hepatocellular carcinoma (HCC). However, there is no consensus as to whether diets that are high in fat or carbohydrates/sugars differentially influence the development of HCC. Moreover, the long-term effects of prenatal HF exposure on HCC and whether this is influenced by postnatal diet has not yet been evaluated. C57BL/6 dams were fed either a low-fat, high-carbohydrate control (C) or low-carbohydrate, high-fat (HF) diet. At weaning, male and female offspring were fed the C or HF diet, generating four diet groups: C/C, C/HF, HF/C and HF/HF. Tissues were collected at 16 months of age and livers were assessed for MASLD and HCC. Glucose regulation and pancreatic morphology were also evaluated. Liver tissues were assessed for markers of glycolysis and fatty acid metabolism and validated using a human HCC bioinformatic database. Both C/HF and HF/HF mice developed obesity, hyperinsulinemia and a greater degree of MASLD than C/C and HF/C offspring. However, despite significant liver and pancreas pathology, C/HF mice had the lowest incidence of HCC while tumour burden was highest in HF/C male offspring. The molecular profile of HCC mouse samples suggested an upregulation of the pentose phosphate pathway and a downregulation of fatty acid synthesis and oxidation, which was largely validated in the human dataset. Both pre-weaning HF diet exposure and post-weaning consumption of a high-carbohydrate diet increased the risk of developing spontaneous HCC in aged mice. However, the influence of pre-weaning HF feeding on HCC development appeared to be stronger in the context of post-weaning obesity. As rates of maternal obesity continue to rise, this has implications for the future incidence of HCC and possible dietary manipulation of offspring carbohydrate intake to counteract this risk.

Long-Term Effects of Childhood Exposure to War on Domestic Violence

AbstractThis paper highlights the scarring effects of early life exposure to civil war, by examining the impact of exposure to conflict in childhood on the incidence of domestic violence in adulthood among married women. To estimate these effects, we use a difference-in-differences model which exploits variation in exposure to Nigeria’s 30-month-long civil war by year of birth and ethnicity. Our results, based on the 2008 Nigerian Demographic Health Survey, show that women exposed to the war during childhood are more likely to be victims of domestic violence in adulthood compared to those not exposed to the war, with larger effects observed for those exposed at younger ages. Additionally, we explore the mechanisms through which exposure to civil war might affect domestic violence and find some support for both the normalisation of violence and weakened bargaining power hypotheses. Understanding the root causes of domestic violence is important given the high prevalence in developing countries and the deleterious consequences for women and their children.

Factors influencing hydrogen migration in cap rocks: Establishing new screening criteria for the selection of underground hydrogen storage locations

Safe and efficient underground storage of hydrogen requires cap rocks with effective sealing capabilities. This study investigates the interplay between various factors and their influence on hydrogen leakage from cap rocks. Compared to other commonly stored gases, hydrogen exhibits a significantly faster leakage rate. This study reveals that pore size and tortuosity of cap rocks play a crucial role. Larger pore sizes and lower tortuosity factors lead to increased leakage. Conversely, higher tortuosity (more twisted pores) enhances the sealing capability. Cap rocks with a tortuosity greater than 3 or an effective pore size below 5 nm demonstrated exceptional sealing capabilities. Beyond pore geometry, the study underscores the dependence of hydrogen diffusivity on prevailing underground conditions. Higher reservoir temperatures translate to a faster leakage rate, whereas increased pressure reduces the mean free path of hydrogen molecules, hindering diffusion and promoting retention within the storage formation. Reservoirs of temperature below 350 K and under a pressure exceeding 13.80MPa (2000 psi) exhibited minimal leakage. These findings underscore the crucial role of meticulous cap rock selection for safe and efficient underground hydrogen storage. This research paves the way for future investigations exploring the impact of additional factors such as the presence of other gases, the chemical composition of the cap rock itself, and the long-term effects of hydrogen exposure on cap rock integrity. A comprehensive understanding of these factors is essential for optimizing underground hydrogen storage strategies and ensuring long-term environmental sustainability.

Interactive effects of long-term exposure to PM10, NO2 and O3 on SARS-CoV-2 infection and severity: a population-based cohort study

Interactive effects of long-term exposure to PM10, NO2 and O3 on SARS-CoV-2 infection and severity: a population-based cohort study

Disparity in the effect of long-term exposure to air pollution on non-communicable disease burden across sub-populations in India

Disparity in the effect of long-term exposure to air pollution on non-communicable disease burden across sub-populations in India

Systematic review on health effects of long-term exposure to UFP

Systematic review on health effects of long-term exposure to UFP

Ozone induced multigenerational glucose and lipid metabolism disorders in Drosophila

Ozone (O3), a persistent pollutant, poses a significant health threat. However, research on its multigenerational toxicity remains limited. Leveraging the Drosophila model with its short lifespan and advanced genetic tools, we explored the effects of O3 exposure across three generations of fruit flies. The findings revealed that O3 disrupted motility, body weight, stress resistance, and oxidative stress in three generations of flies, with varying effects observed among them. Transcriptome analysis highlighted the disruption of glucose metabolism-related pathways, encompassing gluconeogenesis/glycolysis, galactose metabolism, and carbon metabolism. Hub genes were identified, and RT-qPCR results indicated that O3 decreased their transcription levels. Comparative analysis of their human orthologs was conducted using Comparative Toxicogenomics Database (CTD) and DisGeNET databases. These genes are linked to various metabolic diseases, including diabetes, hypoglycemia, and obesity. The trehalose content was reduced in F0 generation flies but increased in F1-F2 generations after O3 exposure. While the trehalase and glucose levels were decreased across F0-F2 generations. TAG synthesis-related genes were significantly upregulated in F0 generation flies but downregulated in F1-F2 generations. The expression patterns of lipolysis-related genes varied among the three generations of flies. Food intake was increased in F0 generation flies but decreased in F1-F2 generations. Moreover, TAG content was significantly elevated in F0 generation flies by O3 exposure, while it was reduced in F2 generation flies. These differential effects of O3 across three generations of flies suggest a metabolic reprogramming aimed at mitigating the damage caused by O3 to flies. The study affirms the viability of employing the Drosophila model to investigate the mechanisms underlying O3-induced glucose and lipid metabolism disorders while emphasizing the importance of studying the long-term health effects of O3 exposure. Moreover, this research highlights the Drosophila model as a viable tool for investigating the multigenerational effects of pollutants, particularly atmospheric pollutants.

Effect of 60 °C sustained temperature conditions on the mechanical properties and microstructure of alkali-activated fly ash-slag pastes and mortars

The temperature effect has been proven to affect the mechanical properties and microstructure of alkali-activated materials greatly. The research on the long-term complex high-temperature environment for alkali-activated materials remains blank. In this paper, the actual working temperature is selected to study the effects of long-term exposure at 60 °C on the mechanical properties of static/impact load, quality, shrinkage deformation, hydration products, pore structure, and microscopic morphology of alkali-activated fly ash-slag (AAFS). The results show that the mass loss rate of AAFS tends to be stable, the shrinkage deformation rate decreases, and the compressive strength decreases after 28d of sustained high-temperature action. The sustained high temperature causes changes in the hydration product phase, mean chain length (MCL) of the gel phase, pore structure, and micro-morphology. When the duration for 7d and 28d at 60 °C temperature, the compressive strength under static and impact loads increases, which is related to the increase of diffraction peak and MCL of the gel phase; when the duration is 60d and 90d, the compressive strength under static/impact loads decreases, which is related to the increase of cumulative pore volume and the decrease of MCL. Sustained high temperature refines the pore diameter of AAFS samples.

Post-Omicron SARS-CoV-2 serostatus in Sierra Leone: A cross-sectional study in a maternity hospital setting in Freetown, November/December 2022

BackgroundSpread of SARS-CoV-2 in Sub-Saharan African countries has been poorly investigated, especially in the later pandemic stages. We aimed to assess the post-Omicron situation in Sierra Leone in November/December 2022 considering SARS-CoV-2 serostatus, vaccinations, and behavioral factors. MethodsIn a cross-sectional study conducted in a maternity hospital in Freetown, Sierra Leone, both patients and staff provided dried blood spot samples for analysis of anti-S and anti-N IgG prevalence using Anti-SARS-CoV-2-ELISA. Additionally, we collected sociodemographic and infection-related information through questionnaires. Outcome parameters included seropositivity, infection-related seroprevalence, and self-reported vaccination status. We used logistic regression to identify associations with prior infection and with vaccination status. ResultsOut of 791 participants (389 patients, 402 staff), 670 (84.7 %) displayed a positive SARS-CoV-2 serostatus resulting from either infection or vaccination. Among a sub-sample of 514 participants within which determination of prior natural infection was possible, 441individuals (85.8 %) were affected. Prior infection was associated with female sex and tertiary education level. Overall, 60.3 % reported having been vaccinated. Staff as opposed to patients, and individuals with higher socioeconomic status were more likely to report vaccination. Individuals who assessed their risk of COVID-19 as either higher or lower compared to a medium-level risk were more likely to have contracted the virus and less likely to have received vaccination. ConclusionOur findings suggest that since the Omicron wave in 2022, the Sierra Leonean population has almost universally been exposed to SARS-CoV-2. While this is encouraging in the light of relatively low excess mortality in the country, future investigations on the long-term effect of high viral exposure on epidemic resilience and public health impact will be crucial.

Early-Life Disease Exposure and Its Heterogeneous Effects on Mortality Throughout Life: Sweden, 1905-2016.

Exposure to infectious diseases in early life has been linked to increased mortality risk in later life in high-disease settings, such as eighteenth- and nineteenth-century Europe. Less is known about the long-term effects of early-life disease exposure in milder disease environments. This study estimates heterogeneous effects from disease exposure in infancy on later-life mortality in twentieth-century Sweden, by socioeconomic status at birth and sex. Using historical population data for southern Sweden, we study 11,515 individuals who were born in 1905-1929 from age 1 until age 85. We measure exposure to disease using the local post-early neonatal mortality rate in the first 12 months after birth and apply flexible parametric survival models. For females, we find a negative effect on life expectancy (scarring) at ages 1-85 following high disease exposure in infancy, particularly for those born to unskilled workers. For males, we find no negative effect on later-life survival, likely because stronger mortality selection in infancy outweighs scarring. Thus, even as the incidence of infectious diseases declined at the start of the twentieth century, early-life disease exposure generated long-lasting negative but heterogeneous population health effects.

Trajectory model to analyze the effect of multi-metal exposures on sperm parameters and sex hormones of the MARHCS cohort in China

BackgroundAt present, several cross-sectional studies have found that exposure to metal/metalloid elements is closely associated with male reproduction. However, the long-term effects of metal exposure on male reproduction have not been explored. MethodsIn 2013, 796 volunteers were recruited, followed by first and second follow-ups in 2014 and 2015. Urine, semen, and blood samples were collected at each stage to examine urinary metal/metalloid levels, sperm parameters, and sex hormones. Initially, the latent class trajectory model (LCTM) was utilized to analyze the trajectories of urinary metals. Subsequently, the effects of urinary metal trajectories on semen parameters and sex hormones were examined using the linear mixed model. Finally, the impact of urinary metal trajectories on the classification of semen quality (normal or abnormal) was evaluated using the generalized linear mixed model. ResultsAmong the 18 metals/metalloids studied, trajectories were formed by 6 of them (Li, Al, Fe, Zn, As, Rb). Further analysis using the linear mixed model and the generalized linear mixed model revealed that Li was negatively correlated with semen volume, and sperm motility (P < 0.05). The maximum-decreasing trajectory group had a detrimental effect on semen quality (OR = 1.75, 95%CI: 1.22, 2.53) compared to the minimum-stable trajectory group. Al showed negative associations with sperm concentration, total sperm count, and normal morphology (P < 0.05). Rb was positively associated with progressive motility (P < 0.05). The high-stable trajectory group exhibited a protective effect on semen quality (OR = 0.66, 95%CI: 0.49, 0.90) compared to the low-stable trajectory group. Additionally, Fe was observed to have a negative relationship with follicle-stimulating hormone (FSH) (P < 0.05), and Rb exhibited a negative correlation with progesterone (P) (P < 0.05). ConclusionOur three-year cohort study provides new evidence that Li and Al have a negative impact on semen quality, whereas Rb is associated with beneficial effects. Additionally, Rb and Fe are endocrine disruptors of sex hormones.

Particulate Matter 2.5 Pollution Impact on Comorbid Cancer and Cardiovascular Disease Mortality in the U.S.

BackgroundEvidence regarding the effect of long-term exposure to particulate matter (PM) 2.5 and comorbid cancer and cardiovascular disease (CVD) mortality is limited. ObjectivesIn this study, the author report the association between long-term exposure to PM 2.5 and CVD mortality, cancer mortality and comorbid cancer and CVD mortality in the U.S. population. MethodsThe Centers for Disease Control and Prevention (CDC) WONDER (Wide-Ranging Online Data for Epidemiologic Research) multiple-cause-of-death database was used to obtain U.S. county-level mortality and population estimates from 2016 to 2020. Data on average daily density of PM 2.5 were abstracted from the 2018 CDC’s National Environmental Public Health Tracking system. Counties were divided into quartiles with Q1 representing counties with least average daily density and Q4 representing counties with maximum average daily density of PM 2.5. Age-adjusted mortality rates were abstracted for each quartile, for the overall population and subgroups of population. ResultsThe age-adjusted mortality rates for CVD, cancer, and comorbid cancer and CVD mortality were 505.3 (range: 505.0-505.7), 210.7 (range: 210.5-210.9), and 62.0 (range: 61.8-62.1) per 100,000 person-years, respectively. CVD mortality had the highest percentage excess mortality in Q4 compared with Q1, followed by comorbid cancer and CVD. Cancer had the least percentage excess mortality. A disproportionate effect of PM 2.5 exposure was noted on vulnerable and minority groups, based on Social Vulnerability Index and race stratification, respectively. ConclusionsHigher levels of long-term PM 2.5 exposure reported increased CVD mortality, cancer mortality and comorbid cancer and CVD disease mortality, with a pronounced detrimental effect in vulnerable and minority population.

Silver nanoparticles alter planktonic community structure and promote ecosystem respiration in freshwater mesocosms

The widespread use of silver nanoparticles (AgNPs) has resulted in their release into the aquatic environment, which threatens the health of aquatic ecosystems. Although the ecotoxicological effects of AgNPs have been widely reported at individual and population levels, the impact of long-term exposure to AgNPs on community structure and ecosystem function in aquatic ecosystems remains poorly understood. Herein, the present study investigated the effects of long-term exposure (28 d) to environmentally relevant concentrations (1 μg/L and 10 μg/L) of AgNPs on the community structure and function of freshwater ecosystems by artificially constructed 28 mesocosms freshwater ecosystem in experimental greenhouses, using plastic water tanks and food web manipulation. The results showed that long-term exposure to AgNPs significantly altered the community structure of zooplankton, phytoplankton, and bacterioplankton in the aquatic ecosystem. Exposure to 10 μg/L AgNPs significantly reduced the zooplankton density (70.3%, p < 0.05) and increased the phytoplankton biomass and bacterial richness and diversity via a “top-down effect.” With regards to ecosystem function, AgNPs exposure significantly increased the respiration in freshwater ecosystems but did not have a significant effect on decomposition. The partial least squares path modeling (PLS-PM) further revealed that AgNPs may have a negative impact on ecosystem functions by reducing zooplankton community density and thus increasing phytoplankton biomass. This study is the first to show that long-term exposure to environmentally relevant concentrations of AgNPs leads to alterations in plankton community structure and promotes respiration in freshwater ecosystems. It emphasizes the need for assessing the environmental risk of long-term exposure to AgNPs at the ecosystem level.

Space radiation research with heavy ions at HIMAC

The HIMAC (Heavy Ion Medical Accelerator in Chiba) was originally designed principally for carbon ion therapy, but heavy ion research projects in medicine, physics, chemistry and biology have been conducted under a collaborative research framework since 1994. One major application is space radiation research. The radiation in space of greatest interest for human space exploration consists of energetic protons and heavy ions which can affect the health of space crew and lead to the failure of electronic devices. Ground-based experiments at heavy ion accelerators are crucial for ensuring mission crew safety and for understanding the biological effects of long-term exposure to space radiation. HIMAC provides a range of linear energy transfer (LET) beams from protons to Xe ions at energies up to 800 MeV/u, representing the most biologically-significant components of the space radiation field. At HIMAC a variety of radiation detectors and instruments are characterized and calibrated for dosimetry using specific mono-energetic heavy ion beams, the performance of shielding materials for mitigating space radiation dose is evaluated, radiation hardness of electronic devices is tested to ensure their safe operation in space, and the radiobiological studies are conducted to understand biological effects in humans during long-term space activities. HIMAC is an indispensable simulator of space radiation for the new decade of space exploration.