Search Results (6,501)

Background/Objectives: Bile acid synthesis disorders (BASDs) represent a distinct category of progressive familiar cholestatic liver disease. A novel targeted mass spectrometry assay was developed for the accurate measurement of the major urinary atypical bile acids and bile alcohols that are biomarkers for HSD3B7, AKR1D1, CYP7B1 and CYP27A1 deficiencies, the four most common BASDs. Methods: Stable-isotope dilution UPLC tandem mass spectrometry was used for the simultaneous quantification of 12 key atypical bile acid biomarkers in urine from patients with BASD. Typical concentration ranges for these metabolites were established from urine samples from patients with biochemically and/or genetically confirmed BASD and compared with non-cholestatic and cholestatic controls. Results: The separation of major 3β-hydroxy-Δ⁵-bile acid sulfates, taurine- and glycine-conjugated 3-oxo-Δ⁴-bile acids, and bile alcohol glucuronides was achieved in a 20 min chromatographic run with intra- and inter-batch imprecisions of <15% for all metabolites. The mean ± SEM urinary concentration of total 3β-sulfated-Δ⁵-cholenoic acids in patients with HSD3B7 deficiency was 704 ± 204 µmol/L (n = 22), approximately 2000-fold higher than in cholestastic patients (n = 168) or non-cholestatic controls (n = 127). Similarly, the concentration of 5β-cholestane-3α,7α,12α,24,25-pentol-glucuronide, the major bile alcohol, in patients with CYP27A1 deficiency was 95 ± 17 µmol/L (n = 12). For CYP7B1 deficiency, two confirmed cases showed elevated levels (average, 7.5 µmol/L) of the glycine conjugate of 3β-sulfooxy-Δ⁵-bile acid. In AKR1D1 deficiency, total 3-oxo-Δ⁴-bile acids in urine were elevated (81 ± 16 µmol/L, n = 48), but concentrations showed overlap with cholestatic and non-cholestatic controls. Conclusions: A novel quantitative tandem mass spectrometry assay is described for the measurement of the major atypical metabolites and biomarkers in urine applicable to the accurate monitoring of treatment responses, and for the first time typical concentration ranges are established for each of these BASDs. Full article

Phosphorites are a vital source of phosphorus for agricultural and industrial applications and are increasingly recognized for their potential as secondary repositories of critical raw materials (CRMs) such as rare earth elements plus yttrium (REYs). This study investigates deep-sea phosphorites from the Galicia Bank, Madeira, and Canary Seamounts, in the NE Atlantic Ocean, which are spatially associated with ferromanganese (Fe-Mn) mineralization. Through integrated petrographic, geochemical, and in situ isotopic analyses (O and Sr), we assess the timing, processes, and paleoenvironmental conditions of phosphogenesis and its implications for CRM enrichment. Rare earth element patterns in apatite reflect a predominant seawater-derived signature with variable Ce anomalies. Nevertheless, variable Y/Ho ratios point to evolving fluid sources including a hydrogenous component (directly derived from seawater), modified porewaters and, locally, volcanic or possibly hydrothermal inputs. Oxygen and strontium isotope compositions constrain phosphogenesis to several episodes ranging from the Upper Cretaceous to the Middle Miocene, with distinct isotopic shifts identifying both primary formation and later overprinting processes mostly linked to Fe-Mn oxyhydroxide growth or volcanic–hydrothermal activity. These findings highlight the dynamic and multiphase nature of phosphorite formation in deep-marine settings. The integration of high-resolution geochemical and isotopic tools proves essential for reconstructing genetic histories, defining metallogenic context and evaluating CRM prospectivity in complex submarine systems. Full article

Following Yangtze River protection policies, many small dams have been removed. Using the Heishui River as an example, we compared food web structures among areas affected by dams (DAs), areas from which dams were removed (DRAs), and natural reference areas (NRAs) using stable isotopes and a Bayesian mixing model. NRAs had balanced basal carbon sources; DAs relied on periphytic algae (43.6%) and POM (23.5%); and DRAs were dominated by periphytic algae (50.8%), with terrestrial inputs lower in both DAs and DRAs. NRAs showed a compressed food chain (1.89–2.23). DAs exhibited an extended but inverted structure, with benthivorous fish (3.00) surpassing carnivores, perhaps reflecting the accumulation of sedimentary organic matter under the lentic conditions created by damming. DRAs expanded the vertical dimension, with carnivorous fish reaching the highest level (3.70). DAs had the fewest nodes (16) but the highest connectance (0.492). DRAs showed the most nodes (20), highest linkage density (4.00), lowest connectance (0.421), and lowest trophic redundancy, indicating functional differentiation. NRAs had an intermediate number of nodes (17) and the lowest linkage density (3.41). These findings indicate that small dam removal altered basal resource use, triggered food web reorganisation that increased the trophic position of carnivorous fish, and enhanced topological complexity, although terrestrial energy inputs in DRA remained below natural levels. Full article

The Huomaxie granite in Ningdu, southern Jiangxi Province, is located in the central part of the Cathaysia Block. Previous studies assigned this pluton to the Huitong batholith as S-type granite, but lacked precise geochronological and petrogenetic constraints. This paper presents systematic petrography, whole-rock geochemistry, zircon U–Pb dating, in situ Hf isotopic analysis, and electron microprobe analysis (EPMA) of muscovite from the muscovite monzogranite of the pluton. The weighted mean ²⁰⁶Pb/²³⁸U age is 420.1 ± 3.1 Ma. The rocks are silicic, high-K calc-alkaline, and peraluminous S-type granites. Zircon ε_Hf(t) values range from −15.0 to −11.8, with two-stage Hf model ages (T_DM2) of 2360–2150 Ma. Geochemical characteristics and muscovite composition data indicate that the magma was derived from high-temperature partial melting of psammitic sedimentary rocks. Tectonic discrimination diagrams suggest that the pluton formed in a post-orogenic extensional setting. It was generated by lower crustal melting induced by asthenospheric upwelling. Full article

The European legislation sets the maximum residue levels for glyphosate in sesame seeds at 0.1 mg/kg (EU Regulation n. 293/2013) and for glufosinate and N-Acetyl-glufosinate expressed as glufosinate at 0.03 mg/kg (EU Regulation n. 2016/1002). The present work describes a rapid methodology to determine glyphosate, glufosinate and its metabolite and N-Acetyl-glufosinate in sesame seeds by LC/MS/MS. The method was studied in the framework of EU proficiency tests on sesame seeds. The analytical method was developed using methanol acidified with formic acid (1%, v/v) extraction with an isotope internal standard, followed by LC/MS/MS detection. The recoveries were performed in the range of 0.05–0.5 mg/kg for glyphosate and 0.02–0.2 mg/kg for glufosinate and N-Acetyl-glufosinate. All the recovery values were between 70 and 114%, which is the acceptable interval according to SANTE/11312/2021; the relative standard deviation (%RSD) values met the requirement of <20%. Linearity for each substance in solvent and matrix was studied, and the response was linear with R2 > 0.999. We considered precision, matrix effect, LOD and LOQ in the validation. All the parameters were in agreement with the acceptability criteria of the document SANTE/11312/2021. The method was considered suitable for the determination of the studied substances on sesame seeds. Full article

Declines of skeletal muscle mass and functions are implicated in the progression of various clinical conditions such as cancers, obesity, insulin resistance, diabetes, and osteoporosis. While no effective and safe drugs against muscle wasting, such as sarcopenia and disease-associated cachexia, have been discovered, it is well documented that dietary essential amino acids (EAAs) or high-quality protein work synergistically to enhance the anabolic effect of resistance exercise training (RT), leading to gains in muscle mass, strength, and muscle quality. Dietary EAAs serve as precursors and signaling molecules for the synthesis of new muscle proteins (both contractile and mitochondrial) and stimulate neuromuscular junction remodeling. Furthermore, EAAs consumed in the post-absorptive state improve endurance capacity via stimulation of mitochondrial biogenesis (independent of PGC1-α) and mitochondrial dynamics (mitochondrial protein synthesis and fission). Here, we discuss (1) traditional molecular mechanisms regulating the muscle proteome through constant turnover (synthesis and breakdown), (2) novel mechanisms by which dietary supplementation of EAAs during RT simultaneously improves muscle strength and endurance, (3) stable isotope tracer methodologies that enable understanding of the dynamic muscle proteome and accurate assessment of functional muscle mass, and finally, (4) clinical implications of combined EAA and RT interventions in the context of muscle and metabolic dysfunction, including sarcopenia, cachexia, obesity, and chronic disease. Collectively, current evidence underscores the potential of balanced EAAs, particularly when combined with resistance training, as a safe, effective, and translationally relevant nutritional strategy to preserve and enhance muscle and metabolic health across healthy and clinical populations. Full article

Understanding how plants regulate nitrogen (N) and carbon (C) allocation among their organs under adverse environmental and climatic conditions remains a significant challenge, despite its direct impact on the value of plant residues and agricultural products. Therefore, this study aimed to examine the dynamics of N and C through their stable isotope ratios in two soybean varieties of differing maturity groups (Merlin and Laulema) inoculated with various nitrogen-fixing Bradyrhizobium japonicum bacterial strains. The contents of N and C as well as their isotopic ratios in soybean plant parts were analyzed at full-flowering (R2) and full-maturity (R8) stages. The results demonstrated overall compatibility between soybean varieties and selected B. japonicum strains, resulting in up to 32 nodules per plant; however, significant variation in root nodule numbers was observed. From a physiological perspective, both the soybean variety and the strain of nitrogen-fixing bacteria significantly influenced nitrogen stable isotope ratios across different plant organs, including roots, shoots, stems, pods, and seeds, with similar trends in δ(¹⁵N) variation among plant parts observed in both varieties. In contrast, the main differences in carbon stable isotope composition were observed among varieties less affected by the amendment strategy. N content was higher in roots and shoots during flowering and declined by twofold in roots and fivefold in aboveground biomass at maturity, reflecting extensive nitrogen remobilization to support seed formation. From an agronomic perspective, the highest yields were achieved by the inoculated soybean Merlin, with more than 3 t ha⁻¹. However, the positive effects of symbiosis can improve yields in less productive varieties like Laulema, making them comparable to those of more productive varieties. Soybean inoculation not only influenced the isotopic redistribution within the plant but also proved to be an effective practice for increasing seed N content, with strain AGF78 producing the highest number of nodules and a significantly high amount of nitrogen in seeds, followed by SEMIA5079, the least effective being RF10. Full article

Tianjin, nestled on the North China Plain, possesses abundant geothermal resources with tremendous potential for development and utilization. This study employs hydrogeochemical and isotopic analysis techniques to thoroughly explore the geochemical characteristics and circulation patterns of geothermal fluids in Tianjin, shedding light on the mechanisms underlying the formation and evolution of deep geothermal fluids. The findings reveal that atmospheric precipitation serves as the primary recharge source for the region’s geothermal fluids, with the calculated recharge heights coinciding with those of the Jixian mountainous area. This precipitation infiltrates through permeable layers and the deep, large faults surrounding the southern plain, entering relatively enclosed or semi-enclosed geothermal reservoirs. As they circulate, the geothermal fluids undergo intricate interactions with the surrounding rocks, including processes such as leaching, adsorption, carbonate reprecipitation, cation exchange, and decarbonation. The fluids circulate at depths ranging from 1.6 to 3.5 km, with temperatures spanning from 67 to 133 °C. Along the flow path, the anionic composition of the geothermal fluids shifts from HCO₃⁻ dominance in the north to a coexistence of Cl⁻ and SO₄²⁻, ultimately dominated by Cl⁻ in the south, accompanied by an increase in total dissolved solids (TDS). The results indicate that Tianjin geothermal fluids are mainly recharged by meteoric water and evolve along their flow paths through dissolution of evaporitic and carbonate minerals, cation exchange, and carbonate precipitation. Hydrochemical and Sr-isotope differences suggest generally limited vertical connectivity among the studied reservoirs, although local hydraulic interaction may occur near conductive faults. These results provide constraints on the hydrogeochemical evolution and management of geothermal resources in the Tianjin sedimentary basin. Full article

The Late Triassic Bolila Formation in the central Qiangtang Basin is a typical carbonate buildup deposited during a regional transgression in the eastern Tethyan realm. Understanding its sedimentary evolution and reservoir-forming mechanisms is crucial for hydrocarbon exploration. This study integrates petrology, detrital zircon U-Pb geochronology, carbon-oxygen isotopes, and reservoir property analysis of the Quemudongda section. The results show: (1) detrital zircon dating provides a maximum depositional age of 225.7–235.7 Ma (Carnian–Norian), correcting the previous Jurassic misassignment on the 1:250,000 geological map. Carbon-oxygen isotopes (average δ¹³C = +3.2‰, δ¹⁸O = −11.1‰) are consistent with the global Carnian–Norian positive δ¹³C excursion. (2) The section reveals a platform-margin reef (hexactinellid and calcareous sponges) and slump breccia (seven layers) association, representing a steep-rimmed carbonate platform margin. The sedimentary evolution comprises three stages: reef initiation, reef flourishing with frequent slumping, and reef decline with dolomitization. (3) Reservoirs are mainly breccia and reef dolostones, with intergranular, intercrystalline, and fracture-related pores. Porosity averages 2.8% (0.8%–7.2%), permeability averages 0.35 mD (0.001–8.5 mD), defining a low-porosity, ultra-low-permeability fracture-pore reservoir. Breccia dolostone has better properties (porosity 3.71%, permeability 2.412 mD). (4) Reservoir formation is controlled by sedimentation (platform-margin facies), diagenesis (dolomitization generates pores, but high-temperature recrystallization causes densification), and tectonics (microfractures enhance permeability). High-quality reservoirs occur where breccia dolostone and fractures overlap. (5) The Bolila reef-shoal complex and the overlying Bagong Formation source rocks form a “lower reservoir—upper source” assemblage, representing a new exploration target in the Tuonamu area. The breccia dolostone–fracture overlap zone is the core “sweet spot”. Full article

Numerous promising cancer treatments currently in clinical trials rely on the production and purification of actinium-225 (²²⁵Ac), an actinide with alpha emissions that can kill cancer cells via targeted alpha therapy. To enable ongoing and future studies, and to support anticipated future demand, it is necessary to increase the supply of ²²⁵Ac. High-energy proton irradiation of thorium metal (Th⁰_(s)) is one of the leading production methods of ²²⁵Ac. This process requires the chemical separation of microscopic amounts (μg) of ²²⁵Ac from large quantities (>10 g) of thorium. Current methods to accomplish this thorium removal step can be slow, tedious, generate large quantities of radioactive liquid waste, and require very strict control of the processing conditions. To improve this separation, we investigated the ability of four nitrate salts (NH₄NO₃, KNO₃, RbNO₃, and CsNO₃) to act as selective Th⁴⁺ _(aq) precipitation agents in the presence of ²²⁵Ac³⁺_(aq) in aqueous nitric acid to allow for their separation through a simple filtration. First, we used an automated separations platform to screen the ability of these nitrate salts to precipitate Th⁴⁺. We found the Th⁴⁺ precipitation yields and amount of precipitating agent needed to maximize this yield were dependent on the identity of the precipitating agent cation. Separation studies with ²²⁵Ac³⁺_(aq) and subsequent down-selection of the most promising Th⁴⁺ precipitating agents and conditions enabled us to develop its effective selective precipitation. We demonstrated that the separation was compatible with Th⁰_(s) quantities that can produce medically relevant amounts of ²²⁵Ac. We observed 99.9% of Th⁴⁺_(aq) could be removed via precipitation with KNO_3(s) in less than two hours in the presence of co-produced isotopes. Meanwhile, other experiments demonstrated that the ²²⁵Ac³⁺_(aq) recovery was > 97% at 1–10 g Th⁰_(s) scale. Full article

Mass spectrometry-based lipidomics has created new opportunities to investigate the role of lipids in coffee quality formation and stability across the production chain. Coffee lipids contribute to flavor precursor formation, aroma release, mouthfeel, and storage behavior, but their molecular remodeling during maturation, processing, roasting, and storage remains insufficiently integrated. This review summarizes recent progress in lipidomics methodologies relevant to coffee research, with emphasis on sample preparation, mass spectrometry platforms, data analysis, and the strengths and limitations of current lipid annotation strategies. It further examines how lipid profiles change during bean maturation, how they differ among coffee species and varieties, and how they are reshaped by postharvest processing, roasting, and storage. However, it is important to note that most of these associations are currently correlational rather than causal; direct evidence linking specific lipid species to particular sensory attributes remains limited. Existing studies suggest that lipid composition, rather than total lipid content alone, is more informative for understanding coffee quality differences and for identifying candidate markers associated with origin, processing method, roasting degree, and storage conditions. In particular, alterations in glycerolipids, glycerophospholipids, fatty acids, diterpenes, and other minor lipid constituents are increasingly associated with lipid oxidation, thermal degradation, and flavor-related transformations in coffee. However, current evidence is still limited by incomplete structural annotation, isomeric ambiguity, platform dependence, and the frequent gap between statistical discrimination and mechanistic validation. Future work integrating high-resolution mass spectrometry, ion mobility, targeted quantification, stable isotope tracing, sensory analysis, and multi-omics approaches will be essential to improve marker reliability and to clarify the functional roles of coffee lipids. Overall, lipidomics provides a promising framework for linking molecular composition with coffee quality control, traceability, and process optimization, although substantial work is still needed to establish mechanistic links to flavor formation. Full article

This study identified δ¹⁵N stable isotope ratios as a robust tracer for fishmeal inclusion in aquaculture feeds. δ¹⁵N and δ¹³C values from fish muscle samples derived from feeding trials with seven species (n = 3–5 fish per diet group) were evaluated (+/−0.1‰ for both δ¹⁵N and δ¹³C; ~1% relative to % N and % C) to verify whether the presence or absence of fishmeal (FM) in feeds could be detected. C and N isotopic data were also analyzed for feed in two of the trials. δ¹³C signatures did not differ consistently across diet groups for each species examined, with mean δ¹³C values for all species investigated being −20.2‰ ± 1.3. In contrast, a strong δ¹⁵N distinction was discerned between FM- and non-FM-fed fish for both muscle and feed samples, with FM-fed groups presenting higher values (p < 0.01) than non-FM-fed groups (range 0.8 to 9.5‰). Dietary ingredients other than FM (e.g., fish oil and algal oil) did not impact the δ¹⁵N isotopic fingerprint, although the addition of poultry byproduct meal to plant-based salmon diets caused an average 0.3‰ difference in δ¹⁵N values. The findings are not absolute as CN isotopes can be used to detect large but not small differences in feed components. Additional research on threshold levels, ingredient sourcing, and species differences is warranted to refine the method to enhance industry transparency and seafood consumer confidence. Full article

Radioisotopic techniques provide powerful tools for reconstructing the history of lake sediments, offering critical insights into past environmental changes and human impacts. These techniques have contributed significantly to our understanding of past environmental change and have implications for current environmental management practices. This review comprehensively examines various radiometric dating techniques used for lake sediments, with a focus on natural, cosmogenic, and artificial radionuclides, including ²¹⁰Pb, ¹³⁷Cs, ²⁴¹Am, ⁷Be, ³H, and ¹⁴C. The review highlights the widespread use of radionuclides in establishing sediment chronologies across different time scales, from short-term processes (days to decades) to long-term environmental reconstructions spanning thousands of years. Moreover, applications in limnological research are explored, including sedimentation rate estimation, reconstruction of pollution history of trace elements, nutrients, microplastics, and organic compounds, and assessment of anthropogenic impacts and catchment changes. The integration of radioisotopic methods with multiproxy paleolimnological approaches is emphasized as a powerful framework for reconstructing past environmental and ecological conditions. Despite their effectiveness, radioisotopic methods are exposed to several sources of uncertainty, including dispersion in atmospheric isotope flux, post-depositional processes, reservoir effects, and model assumptions. These challenges highlight the importance of careful methodological selection, site-specific evaluation, and rigorous uncertainty assessment in radioisotopic studies of lake sediments. Future research should emphasize refining sediment age-model calibration using region-specific sedimentation parameters and standardized validation procedures, and integrating radiometric techniques with geochemical, biological, and paleolimnological proxies to improve the reconstruction of environmental change in lacustrine systems. Such developments would enhance the interpretation of historical pollution records, sediment accumulation patterns, eutrophication history, and ecological variability, thereby providing scientifically robust information to support evidence-based lake management, restoration programs, and long-term conservation strategies. Full article

Organophosphate esters (OPEs) are ubiquitous in the global water environment and may pose potential risks to aquatic ecosystems and human health. Herein, we present a simple and efficient method for accurate quantification of nineteen OPEs in water based on automated liquid–liquid extraction (LLE) with dichloromethane and hexane, followed by gas chromatography–tandem mass spectrometry (GC-MS/MS) with isotope dilution calibration. This method demonstrated a negligible matrix effect, satisfactory recoveries (70–120%), and low limits of detection (0.46–2.32 ng/L). A total of 3, 9, 10, and 11 OPEs were detected in Wahaha pure water, tap water, river water, and seawater, respectively, with total OPE (∑OPE) concentration ranges of 8.23–18.5 ng/L, 159–218 ng/L, 202–623 ng/L, and 111–175 ng/L, respectively. Among the detected OPEs, tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) phosphate (TCIPP) were the predominant compounds in four test water matrices. The risk quotient (RQ) results revealed that OPEs exhibited a low risk to algae, crustaceans and fish in the river water of Zhoushan and seawater of Sanmen Bay. Overall, the proposed method is sensitive and reliable for routine OPE analysis in drinking and environmental waters. Full article

Reservoirs in karst regions exhibit significant carbon sink potential; however, how different reservoir types influence carbon sequestration remains poorly understood. In this study, dual carbon isotopes (δ¹³C–Δ¹⁴C) were applied to trace dissolved organic carbon (DOC) sources in an open reservoir (Aha Reservoir, AHR) and a closed reservoir (Guanshan Lake, GSL) in southwestern China, and to evaluate their carbon sequestration potential. DOC concentrations in GSL were significantly higher than those in AHR (4.14 ± 0.28 mg/L > 3.37 ± 0.30 mg/L) (p < 0.01), along with lower δ¹³C values (−30.34 ± 0.51‰ < −28.18 ± 0.31‰) and more enriched Δ¹⁴C values (−6.94 ± 11.07‰ > −93.74 ± 6.76‰). The δ¹³C–Δ¹⁴C tracing revealed that plants were the primary DOC source for AHR (61 ± 2%), whereas algae dominated DOC sources in GSL (70 ± 2%). Inflow rivers and water retention time (WRT) likely drive differences in DOC sources and concentrations between the two reservoirs. The absence of inflow rivers and the longer WRT in GSL created favorable conditions for algal growth, resulting in substantially higher chlorophyll a (Chl.a) concentrations (103.00 ± 29.87 μg/L > 13.10 ± 3.29 μg/L) and enhanced production of autochthonous DOC through a stronger biological carbon pump (BCP) effect. These conditions further facilitate the formation and accumulation of recalcitrant DOC (RDOC), ultimately increasing DOC concentrations in GSL. Our findings highlight that closed karst reservoirs may represent important yet underappreciated carbon sinks and should receive greater attention in future carbon-sink assessments. Full article