Acid Deposition Research Articles

Quarter century of mercury litterfall at a coniferous forest responding to climate change, Central Europe.

This work evaluated the 25-year-long trends (1994-2018) in mercury (Hg) concentrations and fluxes in spruce litterfall at a forest research plot Načetín (NAC) recovering from acidic deposition in the Ore Mountains, Czech Republic. The mean litterfall Hg deposition averaged 51 ± 18µgm-2year-1, which has been the highest litterfall Hg deposition reported up to date on the European continent. In contrast, the wet deposition (2017-2019) was an order of magnitude lower averaging at 2.5 ± 1.5µgm-2year-1. All the spruce litterfall components bark, twigs, needles, cones, and a mixture of unidentified fragments had elevated mean Hg concentrations relative to background sites averaging 256 ± 77, 234 ± 62, 119 ± 23, 95 ± 14, and 44 ± 15µg kg-1, respectively. Elevated litterfall Hg deposition and concentrations were attributed to the nearby local Hg emission source-coal-fired power plants. Temporally, the decrease of Czech Hg emissions since the 1990s was reflected by the decreasing trend of Hg concentrations in litterfall bark, cones, and twigs, while in needles and other material, Hg increased but insignificantly. Total litterfall ratios of Hg/C, Hg/N, and Hg/S were lower than those in soil O horizons averaging at 0.23 ± 0.04, 9.5 ± 2.0, and 170 ± 37μgg-1, respectively. Since the beginning of monitoring, total litterfall Hg/C exhibited no trend, Hg/N decreased, and Hg/S increased. The litterfall biomass deposition averaging at 469 ± 176gm-2year-1 increased through time resulting in an increased Hg litterfall deposition at NAC by 1.1µgm-2year-1 despite the decreases in Czech Hg emissions. Peaks of annual litterfall Hg deposition up to 96µgm-2year-1 at NAC during the 25years of monitoring resulted from weather extremes such as rime-snow accumulation, wind gusts, droughts, and insect infestation, which all significantly affected the annual biomass deposition. Based on our observations, further increases in biomass and litterfall Hg deposition rates can be expected due to the onset of bark beetle infestation and the increasing number of droughts caused by climate change.

Metabolic effects of phospholipids extracted from capelin (Mallotus villosus) roe on HepG2 cells

This study aimed to evaluate the effects of capelin roe phospholipid (CPL) on lipid accumulation, fatty acid profile, oxidative stress, and changes in target macromolecular structure in HepG2 cells using multidimensional hyperspectral technique. The results showed that CPL significantly inhibited oleic acid-induced accumulation of intracellular lipids and increased the activity of intracellular antioxidant enzymes (CAT, GSH-Px, SOD). The control and CPL-treated groups promoted accumulation of unsaturated fatty acids and reduced deposition of saturated fatty acids. The therapeutic effects of CPL positively correlated with its concentration. Fourier transform infrared spectroscopy and two-dimensional correlation infrared analysis indicated that CPL decreased the relative contents of intracellular carbohydrate, nucleic acid, -CH2-, and ν(C=O)/νas (CH2+CH3), and maintained the order of intracellular protein structure. Fourier transform infrared spectroscopy could be used for label-free cell sorting. This work provided a direction for the subsequent development of functional lipids in aquaculture.

Potential Strategy to Control the Organic Components of Condensable Particulate Matter: A Critical Review.

More and more attention has been paid to condensable particulate matter (CPM) since its emissions have surpassed that of filterable particulate matter (FPM) with the large-scale application of ultralow-emission reform. CPM is a gaseous material in the flue stack but instantly turns into particles after leaving the stack. It is composed of inorganic and organic components. Organic components are an important part of CPM, and they are an irritant, teratogenic, and carcinogenic, which triggers photochemical smog, urban haze, and acid deposition. CPM organic components can aggravate air pollution and climate change; therefore, consideration should be given to them. Based on existing methods for removing atmospheric organic pollutants and combined with the characteristics of CPM organic components, we provide a critical overview from the aspects of (i) fundamental cognition of CPM, (ii) common methods to control CPM organic components, and (iii) catalytic oxidation of CPM organic components. As one of the most encouraging methods, catalytic oxidation is discussed in detail, especially in combination with selective catalytic reduction (SCR) technology, to meet the growing demands for multipollutant control (MPC). We believe that this review is inspiring for a fuller understanding and deeper exploration of promising approaches to control CPM organic components.

The cooperative regulatory effect of the miR-130 family on milk fat metabolism in dairy cows.

There is a strong relationship between the content of beneficial fatty acids in milk and milk fat metabolic activity in the mammary gland. To improve milk quality, it is therefore necessary to study fatty acid metabolism in bovine mammary gland tissue. In adipose tissue, peroxisome proliferator-activated receptor gamma (PPARG), the core transcription factor, regulates the fatty acid metabolism gene network and determines fatty acid deposition. However, its regulatory effects on mammary gland fatty acid metabolism during lactation have rarely been reported. Transcriptome sequencing was performed during the prelactation period and the peak lactation period to examine mRNA expression. The significant upregulation of PPARG drew our attention and led us to conduct further research. According to bioinformatics prediction, dual-luciferase reporter system detection, qRT‒PCR and Western blotting, miR-130a and miR-130b could directly target PPARG and inhibit its expression. Furthermore, triglyceride and Oil Red O staining proved that miR-130a and miR-130b inhibited milk fat metabolism in BMECs, while PPARG promoted this metabolism. In addition, we also found that the coexpression of miR-130a and miR-130b significantly enhanced their ability to regulate milk fat metabolism. In conclusion, our findings indicated that miR-130a and miR-130b could target and repress PPARG and that they also have a functional superposition effect. miR-130a and miR-130b seem to synergistically regulate lipid catabolism via the control of PPARG in BMECs. In the long-term, these findings might be helpful in developing practical means to improve high-quality milk.

E046 Lytic lesions; metastatic disease or gout?

Abstract Background/Aims Uric acid crystal deposition in the spine is uncommonly diagnosed, although the frequency of axial involvement is thought to be as high as 14-35%. Studies have shown that spinal gout is more common in men aged 35-75 years, with a history of chronic polyarticular tophaceous gout which is not optimally controlled being a key risk factor. Recent studies have shown that spinal gout is under and misdiagnosed due to its non-specific presentation of back pain or absence of symptoms. Our case report exemplifies this diagnostic challenge. Methods In this report we describe a case of a 79-year-old male with a history of polyarticular tophaceous gout, chronic kidney disease and previous renal carcinoma treated with curative radiotherapy. He presented with a 4-week history of progressive exertional dyspnoea and orthopnoea. He was commenced on intravenous diuretics which lead to an acute kidney injury, with his eGFR dropping to 14mL/min. His preadmission allopurinol and colchicine were held and clinically he developed a flare of gout affecting his right wrist and right second and third MCP joints. A CT scan of his abdomen and pelvis, carried out to investigate potential bowel obstruction, showed no evidence of obstruction but it did reveal multiple lytic lesions in the spine with potential extension into the spinal canal at T9 and L5. He did not have any back pain and his neurological examination was normal. Results A working diagnosis of spinal metastasis with potential cord compression was made and the patient was commenced on high dose steroids. He subsequently underwent an MRI whole spine which showed marrow abnormalities and destructive soft tissues changes affecting various facet joints in the thoracic and lumbar spine. The primary differential remained metastases but due to the unusual distribution of the marrow changes in which the vertebral bodies were completely spared, the initial CT images were reviewed on spectral scanning which demonstrated uric acid deposition in the affected facet joints. The diagnosis was confirmed as gout in the spine when a PET-CT scan revealed no potential primary source of malignancy. The gout flare in his hand settled with the steroids prescribed to treat the potential cord compression and he continued to deny suffering from back pain. Conclusion A literature search demonstrates that reports of spinal gout being described as lytic lesions on CT are rare. Spinal gout should be considered as a differential in a patient with facet joint lytic lesions on imaging, without involvement of the vertebral body and where no primary malignancy is found. Our case demonstrates how dual energy CT scanning can prevent the need for invasive biopsy in cases of diagnostic uncertainty in patients with a history of poorly controlled chronic tophaceous gout. Disclosure S.K. Stewart: None. D.J. Coulter: None. C. Masih: None.

Naringenin restricts the colonization and growth of Ralstonia solanacearum in tobacco mutant KCB-1.

Bacterial wilt severely jeopardizes plant growth and causes enormous economic loss in the production of many crops, including tobacco (Nicotiana tabacum). Here, we first demonstrated that the roots of bacterial wilt-resistant tobacco mutant KCB-1 can limit the growth and reproduction of Ralstonia solanacearum. Secondly, we demonstrated that KCB-1 specifically induced an upregulation of naringenin content in root metabolites and root secretions. Further experiments showed that naringenin can disrupt the structure of R. solanacearum, inhibit the growth and reproduction of R. solanacearum, and exert a controlling effect on bacterial wilt. Exogenous naringenin application activated the resistance response in tobacco by inducing the burst of reactive oxygen species and salicylic acid deposition, leading to transcriptional reprogramming in tobacco roots. Additionally, both external application of naringenin in CB-1 and overexpression of the Nicotiana tabacum chalcone isomerase (NtCHI) gene, which regulates naringenin biosynthesis, in CB-1 resulted in a higher complexity of their inter-root bacterial communities than in untreated CB-1. Further analysis showed that naringenin could be used as a marker for resistant tobacco. The present study provides a reference for analyzing the resistance mechanism of bacterial wilt-resistant tobacco and controlling tobacco bacterial wilt.

Hydrochemical fingerprints of karst underground river systems impacted by urbanization in Guiyang, Southwest China

Karst groundwater plays an irreplaceable role in the formation and development of urban areas, and land-use and land-cover change (LUCC) and the input of pollutants during the urbanization process would pose potential environmental risks to underground rivers. We analysed the relationship between urbanization processes and underground river hydrochemistry over nearly 35 years in Guiyang city, southwest of China, it was found that concentrations of various cations and anions, as well as total dissolved solids (TDS), gradually increased with the urbanization process, with significant fluctuations during the rapid urbanization periods. The Hydrochemical Facies Evolution Diagram (HFED) clearly showed the influence of urbanization on the hydrochemistry of the underground rivers. The ion ratios of γMg2+/γCa2+—γHCO3−, γNa+/γCl−, Ca2+/Mg2+—Ca2+ or Mg2+/Σ cations, HCO3−/SO42−—HCO3− or SO42−/Σ anions revealed two distinct phases in the hydrochemical evolution of the underground river system, highly consistent with the urbanization process. Before the rapid urbanization, acid deposition and agricultural activities affected the hydrochemistry, with HCO3-Ca·Mg and HCO3·SO4-Ca·Mg as the dominant types controlled by limestone and dolomite dissolution in water-rock interactions. As acid deposition diminished, the input of SO42− from urban sewage compensated for the reduced impact, but the increased impermeable surfaces reduced the infiltration of atmospheric precipitation, leading to a reduced dissolution of dolomite minerals in water-rock interactions, resulting in a decrease in Mg2+ and a change in the hydrochemical type. The hydrochemical type evolved from a single HCO3·SO4-Ca·Mg type and HCO3-Ca·Mg type to multiple types, such as HCO3·Cl-Ca, HCO3•SO4-Ca, HCO3-Ca, and HCO3·SO4-Ca·Mg, and was highly unstable. With changes in land use, the proportions of various cations and anions in the hydrochemistry changed, especially NH4+, NO3−, SO42−, Na+, and Cl−, which were more sensitive to human activities. This study indicated the impact of urbanization on the hydrochemistry of the underground river system, with the input of SO42− from human activities and the increase in paved surfaces due to urbanization collectively altering the hydrochemical types of the underground river system. The rapid response of karst underground river system hydrochemistry indicates a potential impact on groundwater system by urbanization that should not be ignored.

Enhancing permeability and mechanical properties of rubber cement-based materials through surface modification of waste tire rubber powder

In this study, the authors present a detailed investigation into the surface mineralization of recycled rubber powder (RP) to enhance its performance in cement mortars. A modified rubber, referred to as RTC, is produced by employing a straightforward and efficient method involving the deposition of tannic acid (TA) and calcium carbonate (CaCO3, <5 μm) on the surface of RP. The main objective of this research is to elucidate the impact of RTC on the impermeability, mechanical properties, and pore structure of rubberized mortar. Through a comprehensive set of characterizations and tests, we demonstrate the successful deposition of TA and CaCO3 on the RP surface, resulting in RTC with excellent chemical activity and hydrophilicity, while also providing nucleation sites for hydration products. This modification process facilitated improved interfacial affinity with cement paste, enhancing bonding between rubber and cement paste. Remarkably, the incorporation of rubber into mortars with markedly enhanced resistance to permeation, with RTC mortars demonstrating particularly noticeable improvement. The marginal decrease in density in comparison to conventional mortars arises from the rubber's lightweight properties. Moreover, rubber exerts a minor adverse influence on hydration kinetics, yet this detrimental impact is alleviated in mortars incorporating RTC. Notably, the study elucidates the nuanced changes in porosity induced by rubber incorporation, underscoring its influence on the mechanical performance of rubberized cement mortars. The RTC5 mortar with a 5% content demonstrates the most remarkable enhancement compared to RP5 mortar. Overall, this study highlights the potential of surface mineralization of RP as a promising approach for improving the performance of rubberized cement mortars.

Performance of the one-part geopolymer stabilized soft clay under acids attack

The evolution of globalization and rapid industrialization, coupled with intensive human activities, leads to a significant release of acidic gases and particles (e.g., NOX and SO2) is unavoidable. These emissions eventually result in dry and wet acid depositions due to atmospheric circulation. This infiltration of acidic elements alters the chemical properties of water systems, thereby deteriorating ground stability. The economically developed soft clay areas face considerable threats from these acid environmental attacks. This study focused on employing a ''one-part'' geopolymer (OPG) comprising ground granulated blast furnace slag (GGBFS), fly ash (FA), and solid sodium hydroxide (NH) to stabilize the soft clay. Simultaneously, the deterioration behavior of OPG stabilized soft clay under two different acids (HNO3 and H2SO4) with various pH values (pH of 2, 4, and 6) and varied immersion periods up to 240 days was evaluated including the mass loss, neutralization depth (ND), pH value, and unconfined compressive strength (UCS). Additionally, scanning electron microscopy (SEM) and X-ray energy spectrometry (EDS) characterized the evolution of microstructure and hydrate composition of OPG-stabilized soft clay post varied acid immersion. The results highlighted the superior acid resistance of the stabilized soft clay with an 80:20 GGBFS/FA ratio compared to other ratios. The presence of significant hydration products, such as calcium silicate hydrates (C-S-H), calcium aluminate (aluminosilicate) hydrates (C-A-(S)-H), and sodium aluminosilicate hydrates (N-A-S-H), was observed in the OPG stabilized soft clay. In addition, the contents of Si in the OPG played a significant role in enhancing the acid resistance of the OPG stabilized soft clay. Based on these experimental results, two proposed mechanisms detailed the deterioration and acid resistance of the OPG stabilized soft clay under HNO3 and H2SO4 attack. The findings of this study contribute to advancing scientific comprehension concerning the acid resistance of the OPG stabilized soft clay in ground improvement practices.

Changes in microbial composition explain the contrasting responses of glucose and lignin decomposition to soil acidification in an alpine grassland

Soil acidification often suppresses microbial growth and activities, resulting in a negative impact on soil organic carbon (C) decomposition. While the detrimental effects of acidification on soil and plant properties have been extensively studied, less attention has been paid on the shifts in soil microbial communities and their influences of the decomposition of organic C with different chemical complexities. Taking advantage of an acid addition experiment in a Tibetan alpine meadow, here we examined the response of soil microbial communities to soil acidification and microbial effect on the decomposition of organic C with different chemical complexities (i.e., glucose and lignin, representing labile and recalcitrant C respectively). We found that soil acidification had no impact on microbial respiration and microbial abundance even though it decreased bacterial diversity significantly. Soil acidification increased the relative abundance of some microbial taxa, like Alphaproteobacteria and Acidobacteriia in bacteria increased by 36 %, 284 %, and Eurotiomycetes, Sordariomycetes and Leotiomycetes in fungi increased by 145 %, 279 % and 12.7-fold, but decreased the relative abundance of Acidimicrobiia by 33 % in highest acid addition treatment. Changes in microbial communities (bacterial and fungal community composition, the diversity of bacterial community and the ratio of fungi to bacteria) are significantly related to the decomposition of glucose and lignin. More specifically, soil acidification decreased the decomposition of glucose but increased the decomposition of lignin, indicating a trade-off between the decomposition of labile and recalcitrant soil organic C under soil acidification. Overall, shifts in microbial communities under soil acidification might be accompanied by an increased ability to break down more recalcitrant C. This trade-off between the decomposition of labile and recalcitrant C may change soil C quality under future acid deposition scenarios.

Effects of Past Sulfur Deposition on the Soil Microbial Biomass at Spruce Forest Sites

During the last decades, forest soils in Central Europe recovered from former sulfur and acid deposition. As external S input into forests has strongly decreased and legacy S pools in the soils are diminishing, internal S cycling through mineralization will increasingly become important for ecosystem nutrition. However, it is not known how microbial biomass is affected by the S pool change in the formerly S surplus soils. Here, we present data on the status quo of C, N, and S in microbial biomass in relation to contents in mineral soil and organic layer. The results of forest soil in Eastern Germany (low and high liming), which is slowly recovering from former pollution, are compared to those of a site remote from air pollution in the Swiss Alps. The contents of C, N, and S in soil as well as in microbial biomass were clearly higher in the organic layer than in mineral topsoil at all sites. Despite the generally low content in the mineral A-horizon, the clean-air site showed indications of a more active S-turnover as compared to the high-pollution site. Liming at the high-pollution site improved the conditions for microbial growth (pH increase) in the organic layer resulting in more mobile S.

Long‐term changes in stream water chemistry in small forested watersheds in the northern Kanto region

AbstractConcerns have been raised regarding the degradation of stream water quality due to the excessive influx of atmospheric deposition. This study aimed to reveal the long‐term variation in stream water chemistry in approximately 40 forested small watersheds in the northern Kanto region, based on 3 surveys conducted in 1991–1992, 2006–2007, and 2022. The factors influencing each dissolved element were investigated. Regarding long‐term variations in stream water chemistry, relatively stable concentrations of cations (Ca2+, Mg2+, K+, and Na+) and SiO2 were observed. However, the concentrations of anions (Cl−, , and ) decreased due to the improvement in the atmospheric environment and the diminishing effect of fertilization. Furthermore, the recent increase in stream water pH was attributed to an increase in bicarbonate (), compensating for the decrease in anion concentrations relative to cations. Geology was the most significant factor for inter‐watershed variations in cations and SiO2, and this influence remained relatively constant over 30 years. Forest practices, especially fertilization, had a significant effect on Cl− and , and contributed to higher concentrations in the fertilized watersheds than in the non‐fertilized watersheds over the 15 years following fertilization. Sulfate deposition was a significant influencing factor for , and the concentration fluctuated under long‐term variations in deposition over the past 30 years. Despite substantial acid deposition in the study area, the absence of stream water acidification could be attributed to the abundant cation supply from bedrock and volcanic ash, which underwent weathering processes.

Macronutrients, metals, and metalloid concentrations in non-industrial wood ash in relation to provincial land application limits in Ontario, Canada

Non-industrial wood ash (NIWA) provided by residents who heat with wood, is rich in base-cations and other nutrients and may be used as a forest soil amendment to return nutrients lost through acid deposition. However, due to concerns regarding high trace metal concentrations, most wood ash is landfilled in Canada. This study investigated the chemical variability of NIWA of individual samples and homogenized mixtures to determine if they met Ontario provincial trace metal restriction limits. One hundred and seven ash and 10 charcoal samples collected from residents of Muskoka, Ontario, and three 10-sample composites were analyzed. Chemical composition varied among individual samples, but nutrient levels were within or higher than reported ranges for industrial wood ash, while trace metal values were lower. Ninety-seven percent (104 of 107) of the samples were within Ontario Regulation 267/03 of the Nutrient Management Act, and after homogenization, all samples were below soil application restriction limits. This study indicates that NIWA can be safely used as a forest soil amendment but recommends routine testing of batch samples prior to application.

Recycling of animal protein wastes in the formulation of feed for Labeo rohita and Mystus vittatus—a comparative evaluation

Lactic acid bacteria (LAB) are key players in the fermentation of organic wastes and their recycling as feedstuff for fish. Whey, a common dairy byproduct in India, is a cheap source of LAB and can be used to ferment animal byproducts. An experimental study was designed to explore whether the whey fermented animal protein blend (WFAPB) could be used as a fishmeal replacer in the formulation of feed for both stomach-less carp fish Labeo rohita and stomach-bearing catfish Mystus vittatus. Experiments were performed with five isoproteinous, isolipidous, and isoenergetic feeds with WFAPB replacing fishmeal (FM) by 0% (T1), 25% (T2), 50% (T3), 75% (T4), and 100% (T5). Fifteen days of laboratory experiments with these experimental feeds revealed that more than 50% FM replacement level could result in excess postprandial absorption (6 h) of some essential and non-essential amino acids in the plasma of both fish. The postprandial absorption was more in M. vittatus than L. rohita. Ninety-day experiments were conducted in outdoor cement vats to measure growths and deposition of amino acids (AA) in muscle. Regression analysis was performed to find the optimal FM replacement based on four growth parameters and fifteen AA deposition in muscle. A two-phase fuzzy methodology was used to obtain Pareto-optimal replacement levels for each fish. The results demonstrated that FM replacement levels were 7.63% and 36.79% respectively for L. rohita and M. vittatus when only four growth parameters were considered. However, based on the FM replacement level that maximized deposition of 15 amino acids and growth parameters, it was found that 12.23% and 40.02% replacement of FM by the WFAPB was ideal respectively for L. rohita and M. vittatus. The results revealed that only a fraction of both essential and non-essential amino acids absorbed in plasma could be converted into protein and deposited as bound amino acids in the muscle. It is concluded that fermentation by whey is an inexpensive, easily available, and environmentally sustainable technique to recycle animal protein in the formulation of feed for fish, and the stomach-bearing carnivorous fish are more efficient in utilizing fermented animal protein blend than the stomach-less carps.

Browning from headwaters to coastal areas in the boreal region: Trends and drivers

Browning of freshwaters, mainly caused by increased terrestrial organic carbon loading, has been widely studied during the last decades. However, there are still uncertainties regarding both the extent of browning in different aquatic ecosystems and the actual importance of different driving forces and mechanisms. To refine understanding of the extent and causes of browning and its temporal variation, we gathered a comprehensive dataset including 746 Finnish water quality monitoring stations representing various waterbody types: streams, rivers, lakes, and coastal waters. Monotonic trend analyses revealed that TOC concentrations increased in all waterbody types during the study period from 1990 to 2020, whereas non-linear trends indicated that upward trends in TOC concentrations have substantially decreased since the mid-2000s. However, despite the upward trends levelling off, non-linear analyses also indicated decreases in TOC concentrations at only a few stations. As a result, the TOC contents of the majority of Finnish waterbody types in 2020 were at a higher level than in 1990. To examine the driving forces of increasing TOC concentrations, we selected 100 riverine catchments and linked the detected trends to 24 different drivers, including both hydrometeorological and catchment characteristics. The increased TOC concentrations in surface waters could be connected to diverse human impacts: hydrometeorological variables impacted by climate change, decreased acidic deposition, and land use in terms of peatland drainage. The importance of increased temperatures was emphasized, and its role as a driver of increased leaching of organic carbon in the forthcoming years is expected to grow with climate change.

Critical loads for alkalization in terrestrial ecosystems

Critical loads are a risk assessment approach that has supported large decreases in atmospheric acidic deposition globally. In Canada, SOx emissions fell by approximately 70 % between 1990 and 2021, whereas total particulate matter (TPM) emissions increased by about 40 %, mostly after 2010. Base cations are a major component of TPM, and critical load models consider base cation deposition as beneficial to ecosystems insomuch as it reduces the risk of acidification. However, close to point sources, high levels of alkaline dust deposition have altered soil chemistry and caused an undesirable shift in ecosystem state; something that critical loads are designed to prevent. In this study, the simple mass balance model (SMB) was modified with the objective of preventing base cation accumulation in soil above an acceptable threshold. The concept was applied to a forested site close to large emission sources of sulphur, nitrogen, and base cations in the Oil Sands region of Alberta, Canada. At this site, base cation leaching measured at 25 cm was approximately three times higher than estimated background leaching and exceeded combined SO4 + NO3 leaching. The critical load for alkalization was exceeded under each scenario considered in this study, although the exceedance was marginal if all N in current deposition was assumed to leach from soil. While this framework can easily be applied to regional and national critical load efforts, the main uncertainties of the proposed approach include base cation deposition estimates, assumptions regarding the behavior of N in soil, the selection of an appropriate Alkle(crit) and the long-term immobilization of deposited base cations in soil.

Channel catfish, a species with potential deposition of human-beneficial fatty acids

Fatty acids from fish are of great interest for human consumption, and the channel catfish (Ictalurus punctatus) is one of the most important aquaculture species in Mexico and perhaps in other countries with similar resource endowments. Channel catfish occupy a trophic level that theoretically and potentially allows the retention and de novo biosynthesis of long-chain fatty acids (FAs), essential for human nutrition and health. Here, we present an overview of the main features of FAs, their reported average levels and extreme values in channel catfish assessments, and their correlations. The importance of FAs for human consumption and some implications for future research are discussed.

Effect of Low-Temperature Oxygen Plasma Treatment of Titanium Alloy Surface on Tannic Acid Coating Deposition.

In this study, the effect of low-temperature oxygen plasma treatment with various powers of a titanium alloy surface on the structural and morphological properties of a substrate and the deposition of a tannic acid coating was investigated. The surface characteristics of the titanium alloy were evaluated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurements. Following this, the tannic acid coatings were deposited on the titanium alloy substrates and the structural and morphological properties of the tannic acid coatings deposited were subject to characterization by XPS, SEM, and spectroscopic ellipsometry (SE) measurements. The results show that the low-temperature oxygen plasma treatment of titanium alloys leads to the formation of titanium dioxides that contain -OH groups on the surface being accompanied by a reduction in carbon, which imparts hydrophilicity to the titanium substrate, and the effect increases with the applied plasma power. The performed titanium alloy substrate modification translates into the quality of the deposited tannic acid coating standing out by higher uniformity of the coating, lower number of defects indicating delamination or incomplete bonding of the coating with the substrate, lower number of cracks, thinner cracks, and higher thickness of the tannic acid coatings compared to the non-treated titanium alloy substrate. A similar effect is observed as the applied plasma power increases.

Strong variation in Brook Trout trends across geology, elevation, and stream size in Shenandoah National Park

AbstractObjectiveLandscape context structures fish abundance and dynamics, and understanding trends in fish abundance across the landscape is often prerequisite for effective conservation. In this study, we evaluated the status and trends of Brook Trout Salvelinus fontinalis in Shenandoah National Park to understand how these are structured across bedrock geology, elevation, and stream size.MethodsWe used long‐term monitoring data from 94 sites in Shenandoah National Park to evaluate trends in Brook Trout abundance over a 27‐year period (1996–2022) and assess the importance of local environmental covariates using a hierarchical Bayesian N‐mixture model based on depletion sampling. Focal covariates were chosen for their demonstrated importance in structuring fish populations in Shenandoah National Park and elsewhere. Bedrock geology controls sensitivity to acid deposition, watershed area is related to stream habitat features such as complexity and flow variability, and elevation creates gradients in temperature.ResultModels revealed significant decreases in adult Brook Trout abundance over time (95% credible intervals &lt; 0) for 31 of 94 sites (33%), and at least three sites exhibited apparent extirpations over the study period. Estimated Brook Trout abundance declined by 50% or more in approximately 70% of streams across the park over the study period. Sites with the warmest water temperatures exhibited the fastest declines in abundance. However, large watersheds on poorly buffered bedrock exhibited significant gains in abundance over time, suggesting some recovery from acid deposition due to improvements in air quality.ConclusionOur analysis revealed large and divergent changes in Brook Trout abundance over recent decades and suggests the importance of local water temperature and acid sensitivity as probable causal mechanisms. These results highlight the importance of considering local factors when evaluating long‐term trends in stream fish populations. Results of this study can assist the development of targeted conservation actions within Shenandoah National Park and elsewhere.

ROS/MMP-9 mediated CS degradation in BMSC inhibits citric acid metabolism participating in the dual regulation of bone remodelling

It is necessary to figure out the abnormal energy metabolites at the cellular level of postmenopausal osteoporosis (PMOP) bone microenvironment. In this study, we constructed PMOP model by ovariectomy and identified 9 differential metabolites compared with control femur by energy metabolomic. The enrichment analysis of differential metabolites revealed that tricarboxylic acid cycle, glucagon pathway and purinergic signaling pathway were the main abnormal metabolic processes. Citric acid was identified as the key metabolite by constructing compound reaction–enzyme–gene network. The functional annotation of citric acid targets identified by network pharmacological tools indicated that matrix metalloproteinase 9 (MMP-9) may be involved in regulating citric acid metabolism in the osteogenic differentiation of bone marrow mesenchymal stem cell (BMSC). Molecular docking shows that the interaction forces between MMP-9 and citric acid synthase (CS) is −638, and there are multiple groups of residues used to form hydrogen bonds. Exogenous H2O2 promotes the expression of MMP-9 in BMSC to further degrade CS resulting in a decrease in mitochondrial citric acid synthesis, which leads to the disorder of bone remodeling by two underlying mechanisms ((1) the decreased histone acetylation inhibits the osteogenic differentiation potential of BMSC; (2) the decreased bone mineralization by citric acid deposition). MMP-9-specific inhibitor (MMP-9-IN-1) could significantly improve the amount of CS in BMSC to promote cellular citric acid synthesis, and further enhance bone remodeling. These findings suggest inhibiting the degradation of CS by MMP-9 to promote the net production of citric acid in osteogenic differentiation of BMSC may be a new direction of PMOP research.