Prolonged Periods Of Exposure Research Articles

Cognitive decline in relation to later-life high temperature exposure in a Chinese nationwide cohort

Growing evidence has linked extreme temperature with neuropsychiatric disorders under climate warming with frequent extreme heat events over the past decades, while cognitive performance in relation to heat exposure remains largely unstudied, particularly in populations at high vulnerability to climate risks (e.g., China). Based on five survey waves of a nationwide dynamic cohort (2011–2020), we analyzed 47,825 cognitive test records from 14,729 respondents aged 45+ years across 126 Chinese cities. Global cognitive performance and its two dimensions (episodic memory and mental status) was measured using standardized questionnaires. Temperature exposure prior to cognitive tests was assessed using both average temperatures and heat days exceeding predefined temperature thresholds. Linear mixed-effects models were utilized to examine the relationship between high temperature exposure and cognitive function. This study revealed consistent evidence for heat-related declines in global cognitive performance and episodic memory across multiple exposure-window analyses, while robust associations were observed solely during prolonged exposure periods (more than 90 d) for mental status. For each 1-°C rise in annual mean temperature within 1 year prior to investigation, cognitive scores declined by 0.058 (95% CI: −0.079, −0.037) points for global performance, 0.033 (95% CI: −0.048, −0.018) points for episodic memory, and 0.025 (95% CI: −0.038, −0.013) points for mental status, respectively. Similar findings were seen in analyses using heat exposure days defined by multiple temperature percentiles, linking per 10-d increase in heat duration to reduced global cognitive scores ranging from −0.142 (95% CI: −0.214, −0.070) to −0.168 (95% CI: −0.254, −0.082). Despite varied evidence by heat exposure metrics and cognitive dimensions, stratified analyses suggested possibly higher susceptibility among females, less-educated, and urban-dwelling residents to heat-related cognitive impairment. These results provided suggestive evidence for the role of exposure to heat in triggering cognitive impairment in middle-aged and older individuals. This finding may be crucial in developing public health strategies for managing climate change risks of neurobehavioral disorders in a healthy aging society.

Exposure to lipid mixture induces intracellular lipid droplet formation and impairs mitochondrial functions in astrocytes

Astrocytes, the predominant glial cells in the central nervous system (CNS), play diverse roles including metabolic support for neurons, provision of neurotrophic factors, facilitation of synaptic neurotransmitter uptake, regulation of ion balance, and involvement in synaptic formation. The accumulation of lipids has been noted in various neurological conditions, yet the response of astrocytes to lipid-rich environments remains unclear. In this study, primary astrocytes isolated from the neonatal rat cortex were exposed to a lipid mixture (LM) comprising cholesterol and various fatty acids to explore their reaction. Our results showed that astrocyte viability remained unchanged following 24 h of 5% or 10% LM treatment. However, exposure to LM for 96 h resulted in reduced cell viability. In addition, LM treatment led to the accumulation of lipid droplets (LDs) in astrocytes, with LD size increasing over prolonged exposure periods. Following 24 h of LM treatment and then 48 h in fresh medium, a significant reduction in intracellular LD size was observed in cultures treated with 5% LM, while no change occurred in cultures exposed to 10% LM. Yet, exposure to 10% LM for 24 h significantly increased the expression of the cholesterol efflux regulatory protein/ATP-binding cassette transporter (ABCA1) gene, responsible for intracellular cholesterol efflux, resulting in reduced cholesterol content within astrocytes. Moreover, LM exposure led to decreased mitochondrial membrane potential (MMP) and increased levels of mature apoptosis-inducing factor (AIF). The smaller LDs were observed to co-localize with microtubule-associated protein 1A/1 B light chain 3 B (LC3) and lysosomal-associated membrane protein-1 (LAMP-1) in LM-treated astrocytes, coinciding with lysosomal acidification. These results indicate that the continuous buildup of LDs in astrocytes residing in lipid-enriched environments may be attributed to disruptions caused by LM in mitochondrial and lysosomal functions. Such disruptions could potentially impede the supportive role of astrocytes in neuronal function.

Tenascin can inhibit apoptosis induced by copper in silver pomfret (Pampus argenteus)

Silver pomfret, an economically important fish species, encounters significant challenges posed by copper pollution in wild and culturing environment. High level of copper has the potential to accumulate in aquatic organisms over prolonged exposure periods. The extracellular matrix, which is highly susceptible to copper, encompasses various proteins, among which tenascin (TN) might play a crucial role in potentially regulating copper-induced apoptosis. To investigate this hypothesis in fish, we initially identified six TN family members in silver pomfret, namely TNCa, TNCb, TNR, TNXB, TNXBa and TNN. Phylogenetic analysis showed four gene subfamilies, namely TNC, TNR, TNN, and TNX, through comparative analysis with TNs from seven other teleost fish species. Subsequently, we analyzed transcriptome of silver pomfret under copper stress and found differential expression of TN family genes under varying levels of copper stress, particularly TNCa. KEGG enrichment analysis demonstrated a significant enrichment of TN downstream pathway, specifically the Pi3K-AKT signaling pathway. RT-qPCR results indicated up-regulation of TNs and apoptosis inhibition-related genes and down-regulation of apoptosis promotion-related genes within this pathway. Hence, we speculated that TN inhibits copper-induced apoptosis by modulating this particular pathway. To further validate this hypothesis, we established a copper stress cell model using a silver pomfret kidney cell line (PaK) and utilized siRNA to knock down TNCa expression within this cellular model. Comparing RNAi-Cu group to NC-control group, we observed significantly reduced cell viability and intensified apoptosis signals in the former. Additionally, RNAi-Cu group displayed down-regulation of apoptosis inhibition-related genes and up-regulation of apoptosis-related genes in Pi3K-AKT signaling pathway compared to NC-Cu group. These findings indicated that TN might be able to inhibit copper-induced apoptosis through Pi3K-AKT signaling pathway. Ultimately, this study offers foundational knowledge for exploring heavy metal toxicity effect on fishes and some references for utilization of copper in parasite control.

Impact of hydrocarbon exposure on the mechanical properties of rail pads

This study investigates the effect of hydrocarbon exposure on the mechanical behaviour of seat pads used as a part of the fastening system in rail transport. Three different types of rail pads are examined, two made of EPDM (Ethylene Propylene Diene Monomer) and one made of EVA (Ethylene Vinyl Acetate). The results indicate that hydrocarbon exposure has a significant effect on the dynamic stiffness and mass stability of the pads, particularly in the EPDM ones. More specifically, it is observed that EPDM exposure to hydrocarbons increases the flexibility of the pads. Furthermore, for prolonged exposure periods (500 hours), this flexibility can become so pronounced that exhausts the pad's ability to deform under the loads applied during track assembly, which results in a more rigid behaviour than aging. Such findings are important as they suggest that hydrocarbons can negatively impact the performance and safety of rail transport due to the changes induced in critical mechanical properties of pads. Consequently, measures should be taken by contractors and infrastructure managers to reduce the adverse influence of hydrocarbons on rail pads, which contributes to increase the safety and efficiency of rail transport.

Air pollution related adverse respiratory health outcomes in California’s San Joaquin Valley: evidence from 2016 linked emergency department and hospital records

The San Joaquin Valley (SJV) of California has been consistently identified as having one of the highest levels of air pollution in the US. Despite federal and state standards, the SJV has been in non-attainment status for daily PM2.5 concentrations, extreme non-attainment for 8 hr O3 levels, and attainment for NO2. An epidemiological time-stratified case-crossover design was used to estimate the relationship between exposure to NO2, O3, PM2.5 and adverse health outcomes in asthma and upper respiratory infections (URIs). This study compared pollutant exposure effects for each case during limited time intervals and adjusted for seasonality. Elevated concentrations of three criteria outdoor air pollutants are associated with increased asthma and URI-related ED visits and hospitalizations in the SJV for all ages. NO2 exposure increased the odds of having an ED visit by 2.4% in lag 1 (95% CI: 1.017, 1.031). Lags 2, 3, 4, 5, 7, 9, and 14 were statistically significant. O3 modestly increased the odds of ED visits by 0.3% (95% CI:1.000, 1.006) after immediate exposure in the warm season. In the cold season, PM2.5 estimates were significant for all lags except for lags 4 and 12. The two-week lag increased the odds by 28% (95% CI:1.218, 1.345) for ED visits, and 16.5% (95% CI:1.009, 1.345) increased the odds of being hospitalized after cumulative exposure to PM2.5. Findings suggest that SJV residents experience adverse health effects due to elevated exposure to NO2 despite attainment of federal and state pollutant standards. This study provides new evidence about the effects of three criteria air pollutants and adverse health outcomes in the SJV region. The air quality regulatory and public health governing bodies should consider revisions to regional pollutant thresholds and local public health strategies to prevent adverse health outcomes during short and prolonged periods of air pollution exposure.

Impact of Heavy Metal lead acetate on Hematology of Fresh Water Fish Oreochromis niloticus

The current study examines the impact of lead acetate, a heavy metal pollutant, on the hematological changes in freshwater fish, Oreochromis niloticus, following prolonged exposure to significant changes at sub-lethal concentrations. The findings indicated that whereas WBC rose after a prolonged period of exposure, measures like RBC and Hb decreased.

Changes in vitamin D status among adults from the COVID-19 pandemic to post-pandemic normality.

The COVID-19 pandemic has prompted widespread lockdown measures globally, significantly impacting daily activities and outdoor exposure. This study investigates the effect of the pandemic on vitamin D levels and the prevalence of vitamin D deficiency in the adult population, with a focus on gender-specific differences. A total of 1525 adults from Henan Provincial People's Hospital were included. Serum 25-hydroxyvitamin D (25(OH)D) levels were measured using the Elecsys® Vitamin D total kit on the Roche Cobas® 8000 analyzer. The Clinical Application Consensus on Vitamin D and Its Analogs defined deficiency as 25(OH)D levels below 20 ng/ml. Statistical analysis was performed using SPSS 23.0 and GraphPad Prism 8 software. The overall 25(OH)D levels increased from 18.14 ng/ml [IQR: 13.78, 23.68] in 2022 to 19.15 ng/ml [IQR: 14.88, 25.01] in 2023 (p=0.004). Males exhibited significant improvement in 25(OH)D levels from 18.01 ng/ml [IQR: 14.10, 23.53] in 2022 to 20.49 ng/ml [IQR: 16.11, 26.01] in 2023 (p<0.001). The prevalence of vitamin D deficiency decreased from 62% in 2022 to 54.9% in 2023 (p=0.009), with a notable reduction in males (64.1% in 2022 to 47.2% in 2023). Among 168 individuals tested in both years, 25(OH)D levels increased from 20.73 ± 9.37 ng/ml in 2022 to 22.28 ± 8.59 ng/ml in 2023 (p=0.012), and the deficiency rate decreased from 58.3% in 2022 to 47.0% in 2023 (p=0.038). The 40-49 age group showed significant improvement in 25(OH)D levels from 16.10 ng/ml [IQR: 12.41, 21.18] in 2022 to 18.28 ng/ml [IQR: 13.91, 23.86] in 2023 (p=0.005), with a reduction in deficiency rate from 72.8% to 59.9% (p=0.02). Furthermore, in February, March, and April, 2022, 25(OH)D levels were significantly lower compared to 2023 (p<0.001, p=0.002, p<0.001, respectively), accompanied by a higher prevalence of vitamin D deficiency (p<0.001, p=0.015, p<0.001, respectively). This study demonstrates that the COVID-19 pandemic significantly impacted vitamin D levels, leading to an increased prevalence of deficiency, particularly among males. These findings highlight the critical importance of maintaining sufficient outdoor activities to ensure adequate vitamin D levels. The data underscore the need for public health strategies to address potential deficiencies during prolonged periods of limited outdoor exposure.

Environmental hazards of WELGRO® Cu+Zn: A nano-enabled fertilizer

Nanoagrochemicals have the potential to revolutionize agriculture towards a precision farming system, able to reduce application rates and consequently their environmental footprint, while keeping efficacy. Several nanoagrochemicals (including nanopesticides (Npes) and nanofertilizers (Nfer)) are already commercialized but the environmental risk assessment of these advanced materials is often lacking. In the present study, we studied the commercial fertilizer WELGRO® Cu + Zn and assessed its ecotoxicity to the soil invertebrate species Enchytraeus crypticus (Oligochaeta), further comparing it to its individual active substances CuO and ZnO. To get a comprehensive picture of possible effects, we used four types of highly relevant tests in LUFA 2.2 soil: 1) avoidance behaviour (2 days), 2) reproduction (OECD standard, 28 d), 3) its extension (56 d), and 4) the full life cycle (FLC) (46 d) – this high level of hazard screening allows for increased interpretation. The results confirmed the nano-features of WELGRO® and a higher toxicity than the mixture of the individual components CuO + ZnO. E. crypticus avoided the soil spiked with WELGRO® and CuO + ZnO, this being the most sensitive endpoint - avoidance behaviour. Both WELGRO® and the active substances were little to non-toxic based on the OECD standard test. However, the toxicity dramatically increased in the tests focussing on longer-term sustainability measures, i.e., 56 days, ca. 170 for WELGRO®. This seems related to the nano-features of WELGRO®, e.g., slow release of ions from the nanoparticles throughout time. The FLCt results showed WELGRO® affected hatching and juveniles’ survival, being these the most sensitive life stages. Hence, under actual real world field usage scenarios, i.e., based on the recommended application rates, nanoenabled WELGRO® can affect oligochaete populations like enchytraeids, both via the immediate avoidance behaviour and also via prolonged exposure periods.

Nutritional value, elemental bioaccumulation and antioxidant activity of fruiting bodies and mycelial cultures of an unrecorded wild Lactarius hatsudake from Nanyue mountainous region in China

An unrecorded wild mushroom Lactarius hatsudake from Nanyue mountainous region in China was identified. Subsequently, comparative investigation on the nutritional value, elemental bioaccumulation, and antioxidant activity was performed in the fruiting body (FB) and mycelium (MY) samples of this species. It revealed that the contents of moisture (87.66 ± 0.16 g/100 g fw) and ash (6.97 ± 0.16 g/100 g dw) were significantly higher in FB, and the total carbohydrate, fat, and protein concentrations of FB were similar to those in MY. Among nutritionally important elements, FB possessed higher concentrations of potassium (37808.61 ± 1237.38 mg/kg dw), iron (470.69 ± 85.54 mg/kg dw), and zinc (136.13 ± 5.16 mg/kg dw), whereas MY was a better source of magnesium (1481.76 ± 18.03 mg/kg dw), calcium (2203.87 ± 69.61 mg/kg dw), and sodium (277.44 ± 22.93 mg/kg dw). According to the health risk estimation, FB might pose an aluminum-related health problem when a prolonged period of exposure, while MY was risk-free for consumers. The results of antioxidant capacity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays) in FB and MY were within the range of 104.19 ± 5.70 mg ascorbic acid equivalents (AAE)/g to 169.50 ± 4.94 mg AAE/g, and half maximal effective concentration EC50 values ranged from 0.23 ± 0.01 mg/mL to 0.62 ± 0.05 mg/mL. The aqueous extracts of MY demonstrated a strong ABTS radical scavenging capacity with the highest AAE value.

Natural weathering of spruce wood chemically modified by re‐used ε‐caprolactone solution

AbstractIncreasing environmental pressures over the last few years have led to attention for non‐biocide treatments in the wood protection field. The ε‐caprolactone modification of wood by substitution or blocking of hydroxyl groups with hydrophobic poly(ε‐caprolactone) (PCL) is one of the novel modification methods developed in recent years. In this study, ring‐opening polymerisation of ε‐caprolactone in wood cell walls was evaluated by the third and sixth re‐use of recovered monomer and by oven‐curing method. Spruce samples were modified by re‐used ε‐caprolactone and exposed to the natural weathering agents for 12 months. After weathering, the colour change, surface roughness measurements, and macroscopic and ultra‐microscopic observations revealed that the modified wood had better surface properties than reference wood. Fourier‐transform infrared (FTIR) analysis proved that PCL could be found on the weathered surface up to the sixth month, but very little amount was detected on the surfaces with a longer weathering period. The results clearly showed that the efficiency of PCL modification with re‐use of the monomer solution was sufficient during the initial weathering periods, but efficiency was reduced after a prolonged exposure period.

Impact of Low-Dose Melatonin Supplementation on Testosterone Levels in U.S. Adult Males

ObjectiveAmidst the rapid rise in melatonin supplementation, decreased testosterone levels amongst males in recent decades, and the unclear association between melatonin and the hypogonadal-pituitary-gland (HPG) axis, this study aimed to further examine the association between melatonin use and testosterone levels among men in a nationally representative sample. MethodsU.S. men over the age of 18 surveyed from 2011-2016 via the National Health and Nutrition Examination Survey (NHANES) without missing demographic or pertinent health information were included in the analysis. A total testosterone (TT) level of less than 300 ng/dL was considered low. An average daily dose (ADD) was calculated to quantify participants’ exposure to melatonin supplementation in the past 30 days. ResultsAnalysis included 7,656 participants after selection criteria. The median age of participants was 47 [31-63] years old; the median TT level was 389.9 [289 - 513.9] ng/dL. Melatonin intake was reported in 51 (0.7%) individuals with an ADD of 1 [0.4 - 3] mg/day. We found no association between melatonin intake in the past 30 days and low TT levels (OR = 0.958, 95% CI: 0.496 -1.850; P=0.898). As expected, increasing BMI (OR = 1.133, 95% CI: 1.122 – 1.144; P < 0.001) and older age (OR = 1.019, 95% CI: 1.016 – 1.022; P < 0.001) were associated with low TT levels. ConclusionPredominantly low-dose melatonin supplementation was not associated with low TT levels. Future studies are needed to better quantify the relationship between melatonin intake and low TT levels, especially in the setting of supratherapeutic doses and prolonged periods of exposure.

Evaluating the Impact of Thermal Processing on the Anti-Inflammatory Activity of Non-Centrifugal Cane Sugar: Implications on Cytokine Secretion and TLR4 Signaling.

Plant-derived products have gained considerable attention as inflammation modulators given the wide variety of anti-inflammatory phytochemicals reported to be present in plants and their limited side effects in vivo during prolonged exposure periods. Non-centrifugal cane sugar (NCS) has been identified as a promising sugarcane-derived product due to its high polyphenolic composition and antioxidant potential, but its incorporations into nutraceuticals and other relevant products of biomedical interest has been limited by the ample composition-wise variability resulting from extreme and loosely controlled processing conditions. Here, we assessed the effect of reducing thermal exposure during NCS processing on the retained polyphenolic profiles, as well as on their antioxidant and anti-inflammatory activities. Specifically, we proposed two modified NCS production methods that reduce exposure to unwanted thermal processing conditions by 1) limiting the employed temperatures through vacuum-aided dehydration and 2) by reducing exposure time through refractance window evaporation. By comparing the modified NCS products with traditional NCS, we showed that the proposed process strategies yield enhanced polyphenolic profiles, as evidenced by the results of the Folin-Ciocalteu polyphenol quantification method and the components identification by HPLC coupled to mass spectrometry. Although these compositional differences failed to impact the antioxidant profiles and cytocompatibility of the products, they showed an enhanced anti-inflammatory potential, given their superior modulation capacity of inflammatory cytokine secretion in both systemic and neuroinflammatory scenarios in vitro. Moreover, we showed that both modified NCS products interfere with TLR4 signaling in human monocytes to a significantly greater extent than traditional NCS. However, the anti-inflammatory effect of NCS produced under window refractance evaporation was slightly superior than under vacuum-aided dehydration, demonstrating that reducing exposure time to high temperatures is likely more effective than reducing the operation temperature. Overall, these findings demonstrated that limiting thermal exposure is beneficial for the development of NCS-based natural products with superior anti-inflammatory potential, which can be further exploited in the rational design of more potent nutraceuticals for potentially preventing chronic inflammatory diseases.

Regulation of macrophage IFNγ-stimulated gene expression by the transcriptional coregulator CITED1.

Macrophages serve as a first line of defense against microbial pathogens. Exposure to interferon-γ (IFNγ) increases interferon-stimulated gene (ISG) expression in these cells, resulting in enhanced antimicrobial and proinflammatory activity. Although this response must be sufficiently vigorous to ensure the successful clearance of pathogens, it must also be carefully regulated to prevent tissue damage. This is controlled in part by CBP/p300-interacting transactivator with glutamic acid/aspartic acid-rich carboxyl-terminal domain 2 (CITED2), a transcriptional coregulator that limits ISG expression by inhibiting STAT1 and IRF1. Here, we show that the closely related Cited1 is an ISG, which is expressed in a STAT1-dependent manner, and that IFNγ stimulates the nuclear accumulation of CITED1 protein. In contrast to CITED2, ectopic CITED1 enhanced the expression of a subset of ISGs, including Ccl2, Ifit3b, Isg15 and Oas2. This effect was reversed in a Cited1-null cell line produced by CRISPR-based genomic editing. Collectively, these data show that CITED1 maintains proinflammatory gene expression during periods of prolonged IFNγ exposure and suggest that there is an antagonistic relationship between CITED proteins in the regulation of macrophage inflammatory function. This article has an associated First Person interview with the first author of the paper.

Physiological Changes Associated with Space Missions: How Physical Exercise Helps

Physiological Changes Associated with Space Missions: How Physical Exercise Helps

The Stegodon Bonebed of the Middle Pleistocene Archaeological Site Mata Menge (Flores, Indonesia): Taphonomic Agents in Site Formation

The Middle Pleistocene fluvial channel site of the Upper Fossil-bearing Interval at Mata Menge in the So’a Basin, Flores, Indonesia, has yielded the earliest fossil evidence for Homo floresiensis in association with stone artefacts and fossils of highly endemic insular fauna, including Stegodon, giant rats, crocodiles, Komodo dragons, and various birds. A preliminary taphonomic review of the fossil material here aimed to provide additional context for the hominin remains in this bonebed. Analysis was performed on two subsets of material from the same fluvial sandstone layer. Subset 1 comprised all material from two adjacent one-metre square quadrants (n = 91), and Subset 2 all Stegodon long limb bones excavated from the same layer (n = 17). Key analytical parameters included species and skeletal element identification; fossil size measurements and fragmentation; weathering stages; bone fracture characteristics; and other biological and geological bone surface modifications. Analysis of Subset 1 material identified a highly fragmented assemblage with a significant bias towards Stegodon. A large portion of these bones were likely fractured by trampling prior to entering the fluvial channel and were transported away from the death-site, undergoing surface modification causing rounding. Subset 2 material was less likely to have been transported far based on its limited susceptibility to fluvial transport. There was no significant difference in weathering for the long limb bones and fragments, with the highest portion exhibiting Stage 2 weathering, indicating that prior to final burial, all material was exposed to prolonged periods of surface exposure. Approximately 10% of all material have characteristics of fracturing on fresh bone, contributing to the taphonomic context for this bonebed; however insufficient evidence was found for anthropogenic modification.

Three month inhalation exposure to low-level PM2.5 induced brain toxicity in an Alzheimer's disease mouse model.

Although numerous epidemiological studies revealed an association between ambient fine particulate matter (PM2.5) exposure and Alzheimer’s disease (AD), the PM2.5-induced neuron toxicity and associated mechanisms were not fully elucidated. The present study assessed brain toxicity in 6-month-old female triple-transgenic AD (3xTg-AD) mice following subchronic exposure to PM2.5 via an inhalation system. The treated mice were whole-bodily and continuously exposed to real-world PM2.5 for 3 months, while the control mice inhaled filtered air. Changes in cognitive and motor functions were evaluated using the Morris Water Maze and rotarod tests. Magnetic resonance imaging analysis was used to record gross brain volume alterations, and tissue staining with hematoxylin and eosin, Nissl, and immunohistochemistry methods were used to monitor pathological changes in microstructures after PM2.5 exposure. The levels of AD-related hallmarks and the oxidative stress biomarker malondialdehyde (MDA) were assessed using Western blot analysis and liquid chromatography-mass spectrometry, respectively. Our results showed that subchronic exposure to environmental levels of PM2.5 induced obvious neuronal loss in the cortex of exposed mice, but without significant impairment of cognitive and motor function. Increased levels of phosphorylated-tau and MDA were also observed in olfactory bulb or hippocampus after PM2.5 exposure, but no amyloid pathology was detected, as reported in previous studies. These results revealed that a relatively lower level of PM2.5 subchronic exposure from the environmental atmosphere still induced certain neurodegenerative changes in the brains of AD mice, especially in the olfactory bulb, entorhinal cortex and hippocampus, which is consistent with the nasal entry and spreading route for PM exposure. Systemic factors may also contribute to the neuronal toxicity. The effects of PM2.5 after a more prolonged exposure period are needed to establish a more comprehensive picture of the PM2.5-mediated development of AD.

Evaluation of Heavy Metals Concentration in Some Bottled Water Brands in Kurdistan Region

Recently Bottled waters became the main resources for drinking water supply, where the use of bottled waters in some region has exchanged the distribution system of drinking water. However, several different chemicals may be found in drinking bottled water, for instance heavy metals, that have accumulated in lethal amounts which could affect human health after prolonged periods of exposure. Therefore, this study was carried out to evaluate some bottled water brands in Kurdistan region of Iraq in term of their contents of heavy metal comparing with both WHO and SQI water standards. About 108 samples were collected (18 brands; 6 samples from each brand) from October to December 2019, bought randomly from grocery shops and supermarkets in Duhok, Erbil and Sulaymaniyah city, Kurdistan region, Iraq. Cobalt (Co), Cadmium (Cd), Lead (Pb), Copper (Cu), Chromium (Cr), Iron (Fe), Selenium (Se) and Mercury (Hg) concentrations were determined by atomic absorption spectrophotometer. Heavy metal pollution index (HPI), degree of contamination (Cdeg) and heavy metal evaluation index (HEI) were also calculated for evaluating the overall quality of bottled water. Results of individual criteria revealed that, excluding Cd and Hg, heavy metals content in all bottled water samples were lower than approved limits according to Iraqi's (IQS:417) and WHO standards. Though, the results exhibited that Cd content in some of the studied water samples was greater than the allowable limits (3μg/L) according to the depended standards. Concerning the values of metal pollution indices, although there were higher HPI values than critical value (100) in three water brands i.e. Al-Joud, Al-Waha and Sanbenedetto, the indices values for all other bottled water were below the critical value. According to the results of this study, it can be concluded that except for Cd value in few brands and all Hg values, the studied bottled water are safe for drinking. Moreover, companies of bottled water package are recommended to monitor their products through analyzing the water sample periodically and use activated carbon filtration to ensure the safety of drinking bottled water.

Investigating potential associations between O3 exposure and lipid profiles: A longitudinal study of older adults in Beijing

Background: Little information exists on the lipidemic effects of ozone exposure. Few studies have focused on the different patterns of the association among older adults population, and little attention has been given to comprehensive lipid indices when evaluating the effect of O3 exposure on the metabolism. Methods: We conducted a longitudinal study involving 201 older adults in Beijing, China between 2016-2018. A mixed regression model was applied with random effects to investigate the relationship between O3 and lipid profiles. Results: O3 exposure positively correlated with TC, LDL-C, CRI-I, CRI-II and AC at short-term and medium-term exposure periods. The largest increases in TC, LDL-C, CRI-I and CRI-II were found in the 28-days moving average indicating accumulative effects over prolonged exposure period. A 10μg/m3 increase of O3 at the 28-days moving average was associated with a significant increase of 3.9% (95% CI: 1.0, 6.9) in TC, 8.2% (95% CI: 4.2, 12.4) in LDL-C, 4.8% (95% CI: 1.1, 8.5) in CRI-I and 7.0% (95% CI: 2.7, 11.5) in CRI-II. Stratification by health status and characteristics revealed different patterns of lipid changes among older adults, lipid status, age, sex and BMI may modify the relationship between O3 exposure and lipid profiles. Conclusions: Our findings suggest that short-term and medium-term O3 exposure is associated with lipid profiles abnormalities among the older adults. Evidence also suggests there are patterns within population which differ according to both health status and demographic characteristics.

Examining impact of vapor-induced crosslinking duration on dynamic mechanical and static mechanical characteristics of silane-water crosslinked polyethylene compound

Silane-crosslinked polyethylene (Si-XLPE) compounds are widely used cable insulation materials, cured by water as the crosslinking inducer. Herein, an attempt was made to evaluate the alterations of dynamic mechanical and static mechanical properties of Si-XLPE by increasing the water vapor-triggered crosslinking duration. The criterion for determining the progress of crosslinking was based on an industrially-used method (hot set test), and results indicated 16 h of vapor exposure as an appropriate duration for approaching maximum attainable crosslinking extent. Progress in crosslinking during this period was confirmed by FTIR spectroscopy. DMA was employed to assess the variations of dynamic mechanical behavior. Extending the crosslinking duration affected the storage modulus noticeably, and decreased it due to adverse effect of crosslinking on crystallinity. DSC confirmed the diminishment of crystallinity owing to the extended crosslinking time. Furthermore, prolonged vapor exposure period impacted β and γ transitions due to the influence of formed crosslinks on the mobility of chains. Tensile testing was carried out to ascertain the static mechanical characteristics of crosslinked samples. Findings demonstrated that tensile strength at yield increased below 5%, and tensile stress at break grew around 17%. Besides, elongation and Young's modulus experienced nonmonotonic changes due to the lengthened crosslinking period.

Seasonal morphotypes of Drosophila suzukii differ in key life-history traits during and after a prolonged period of cold exposure.

Seasonal polyphenism in Drosophila suzukii manifests itself in two discrete adult morphotypes, the “winter morph” (WM) and the “summer morph” (SM). These morphotypes are known to differ in thermal stress tolerance, and they co‐occur during parts of the year. In this study, we aimed to estimate morph‐specific survival and fecundity in laboratory settings simulating field conditions. We specifically analyzed how WM and SM D. suzukii differed in mortality and reproduction during and after a period of cold exposure resembling winter and spring conditions in temperate climates. The median lifespan of D. suzukii varied around 5 months for the WM flies and around 7 months for the SM flies. WM flies showed higher survival during the cold‐exposure period compared with SM flies, and especially SM males suffered high mortality under these conditions. In contrast, SM flies had lower mortality rates than WM flies under spring‐like conditions. Intriguingly, reproductive status (virgin or mated) did not impact the fly survival, either during the cold exposure or during spring‐like conditions. Even though the reproductive potential of WM flies was greatly reduced compared with SM flies, both WM and SM females that had mated before the cold exposure were able to continuously produce viable offspring for 5 months under spring‐like conditions. Finally, the fertility of the overwintered WM males was almost zero, while the surviving SM males did not suffer reduced fertility. Combined with other studies on D. suzukii monitoring and overwintering behavior, these results suggest that overwintered flies of both morphotypes could live long enough to infest the first commercial crops of the season. The high mortality of SM males and the low fertility of WM males after prolonged cold exposure also highlight the necessity for females to store sperm over winter to be able to start reproducing early in the following spring.