Acid Form Research Articles

Excited-State Proton Transfer Dynamics of Cyanonaphthol in Protic Ionic Liquids: Concerted Effects of Basicity of Anions and Alkyl Carbons in Cations.

Excited-state proton transfer (ESPT) reactions of 5-cyano-2-naphthol (5CN2) and 5,8-dicyano-2-naphthol (DCN2) were investigated in protic ionic liquids (PILs) composed of quaternary ammonium (NnnnH+) (n = 2, 4, or 8) and hexanoate (C5H11COO-) using time-resolved fluorescence spectroscopy. The effects of the number of alkyl carbons in the cation and the basicity of the anion on the reaction yield and dynamics were examined. In a series of [NnnnH][C5H11COO], fluorescence from the hydrogen-bonding complex (AHBX-*) of a proton-dissociated form (RO-*) with a solvent acid in the electronic excited state was observed between the fluorescence bands of an acidic form (ROH*) and an anionic form (RO-*) as in the case of [N222H][CF3COO] (Fujii et al., J. Phys. Chem B, 2017, 121, 6042). The yield, formation rate, and decay rate of AHBX-* were assessed by the steady-state fluorescence intensity ratio of AHBX-* to RO-* and by analysis of the time-resolved fluorescence spectra within several tens of nanoseconds. The stability of AHBX-* was significantly different from that in [N222H][CF3COO] and depended on the number of alkyl carbons in the cation. The formation of AHBX-* was quite fast compared to the case in [N222H][CF3COO] and almost close to the excitation pulse width. Excitation wavelength dependence of the fluorescence dynamics was observed within several hundred picoseconds for the series of [NnnnH][C5H11COO]. The origin was ascribed to the complex with solvent IL formed in the electronic ground state, as suggested by the density-functional theory (DFT) calculations.

Transcriptome Analysis Reveals Key Genes Involved in the Response of Triticum urartu to Boron Toxicity Stress

The domestication and breeding of wheat genotypes through the years has led to the loss in their genetic variation, making them more prone to different abiotic stresses. Boron (B) toxicity is one of the stresses decreasing the wheat cultivars’ yield in arid and semi-arid regions around the world. Wild wheat progenitors, such as Triticum urartu Thumanian ex Gandilyan, possess a broader gene pool that harbors several genes conferring tolerance to various biotic and abiotic stresses. Unfortunately, T. urartu is not well-explored at the molecular level for its tolerance towards B toxicity in soil. In this study, for the first time, we compared the transcriptomic changes in the leaves of a high B-tolerant T. urartu genotype, PI662222, grown in highly toxic B (10 mM B in the form of boric acid) with the ones grown in the control (3.1 μM B) treatment in hydroponic conditions. The obtained results suggest that several mechanisms are involved in regulating the response of the studied T. urartu genotype toward B toxicity. All the growth parameters of T. urartu genotype, including root–shoot length, root fresh weight, and root–shoot dry weight, were less affected by high boron (10 mM) as compared to the boron-tolerant bread wheat cultivar. With a significant differential expression of 654 genes, 441 and 213 genes of T. urartu genotype were down- and upregulated, respectively, in the PI662222 leaves in high B in comparison to the control treatment. While key upregulated genes included those encoding RNA polymerase beta subunit (chloroplast), ATP synthase subunit gamma, chloroplastic, 60S ribosomal protein, and RNA-binding protein 12-like, the main downregulated genes included those encoding photosystem II protein D, ribulose bisphosphate carboxylase small subunit, and peroxidase 2-like. Interestingly, both Gene Ontology enrichment and KEGG pathways emphasized the possible involvement of the genes related to the photosynthetic process and apparatus in the high B tolerance of the T. urartu genotype. The further functional characterization of the identified potential T. urartu genes will facilitate their utilization in crop improvement programs for B toxicity stress.

Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults.

Vitamin C is an antioxidant and is essential for immune function and infection resistance. Supplementation is necessary when a sufficient amount of vitamin C is not obtained through the diet. Alternative formulations of vitamin C may enhance its bioavailability and retention over traditional ascorbic acid. This systematic review consolidates the evidence on this and the effects on immunity and infection. A systematic literature search was conducted in October 2024 in Embase and Medline, focused on healthy adults (Population); oral forms of liposomal-encapsulated ascorbic acid, liposomal-encapsulated lipid metabolite ascorbic acid, calcium ascorbate, slow-release ascorbic acid, or lipid metabolite ascorbic acid (Intervention); compared to placebo/others (Comparison); in terms of bioavailability, absorption, vitamin C concentration in plasma, serum, and leukocytes, and impacts on tolerability, immunity, and infection (Outcome); and included randomized or non-randomized controlled trials, single-arm trials, and observational studies (Study design). Thirteen studies were included, several evaluating calcium ascorbate in combination with vitamin C metabolites, including L-threonate, referred to here as Calcium ascorbate EC (Ester C®; n = 7). No safety or tolerability concerns were noted with Calcium ascorbate EC vs. placebo or ascorbic acid. Calcium ascorbate EC showed better tolerability and fewer epigastric adverse events, improved quality of life, and induced favorable oxalate changes vs. ascorbic acid. Four studies reported leukocyte vitamin C concentration, some showing higher concentrations with Calcium ascorbate EC vs. ascorbic acid; seven reported more favorable plasma concentrations with the alternative forms over ascorbic acid or placebo; one reported higher serum vitamin C levels with vitamin C lipid metabolites than with Calcium ascorbate EC, calcium ascorbate, and ascorbic acid. No study reported retention in tissues. One study reported a favorable impact of Calcium ascorbate EC on immune parameters, and one found an association of Calcium ascorbate EC with fewer colds and a shorter duration of severe symptoms vs. placebo. Findings suggest that alternative vitamin C forms can improve leukocyte vitamin C, sometimes without affecting plasma levels. Most studies (77%) had a low risk of bias. In conclusion, the type and delivery modality of vitamin C can impact its bioavailability and functionality. Studies highlight the advantages of Calcium ascorbate EC over traditional ascorbic acid in terms of its tolerability and its potential to increase leukocyte vitamin C concentrations, crucial for immune function and protection against infection. However, further research is required to conclusively establish its effects on immune health.

Concurrent targeted delivery of doxorubicin and curcumin to the cancer cells using simple and versatile ligand-installed multifaceted chitosan-based nanoconjugates.

Existing chemotherapeutic approaches against refractory cancers are ineffective due to off-target effects, inefficient delivery, and inadequate accumulation of anticancer drugs at the tumor site, which causes limited efficiency of drug treatment and toxicity to neighboring healthy cells. The development of nano-based drug delivery systems (DDSs) with the goal of delivering desired therapeutic doses to the diseased cells and has already proven to be a promising strategy to address these challenges. Our study focuses on achieving an efficient tumor-targeted delivery of a combination of drugs for therapeutic benefits by developing a versatile DDS by following a simple one-step chemical approach. We used low-molecular-weight chitosan and modified its primary amine groups with reactive forms of cholesterol and folic acid by simple chemical tools and thus prepared folic acid-chitosan-cholesterol graft copolymer. The polymer contains numerous residual primary amine groups, which offer enough water solubility and positive charge to its polymeric backbone to foster the interaction of negatively charged and/or hydrophobic drugs to load and encapsulate a wide variety of drugs within it via various non-bonding interactions. We used curcumin and doxorubicin as the combination of drugs and thus finally prepared targeted nanoconjugates (targeted NCs). In vitro cellular experiments show that our developed targeted NCs demonstrate 3-5 times higher cellular uptake than non-targeted NCs at various incubation times (2 h, 8 h, and 12 h) in KB cells where folate receptors are overexpressed. This enhanced cellular uptake of targeted NCs and the following delivery of drugs in the cytosol and its disposition to the nucleus exhibit a substantial amount of toxicity to KB cells towards an effective therapeutic strategy for treatment.

Linoleic acid alleviates aluminum toxicity by modulating fatty acid composition and redox homeostasis in wheat (Triticum aestivum) seedlings.

Lipids, as key components of biological membranes, play vital roles in sensing and initiating plant responses to various abiotic stresses. Here, the alteration of membrane fatty acids in wheat roots under Al stress was investigated using two genotypes differing in Al tolerance, and the role of linoleic acid in Al tolerance was comprehensively explored. Significant differences in the fatty acid profiles were observed, with increased linoleic acid accumulation in the Al-tolerant genotype. Supplementation with linoleic acid enhanced fatty acid synthesis, reduced membrane lipid saturation, improved membrane fluidity, and alleviated root growth inhibition. Wheat seedlings treated with linoleic acid exhibited a reduction in lipid peroxidation, as evidenced by decreased levels of malondialdehyde and lipid hydroperoxides. Furthermore, the application of linoleic acid increased the total contents and reduced forms of ascorbic acid (AsA) and glutathione (GSH), thereby restoring the cellular redox balance in wheat roots under Al stress. The elevated levels of AsA and GSH maintained by linoleic acid, can be attributed to the high efficiency of the AsA-GSH cycle, as linoleic acid enhanced the activities of the antioxidant enzymes involved. These results suggest that linoleic acid enhances wheat Al tolerance by maintaining both fatty acid synthesis and the levels of unsaturated fatty acids, as well as protecting membrane lipids from peroxidation by reactive oxygen species through the regulation of the AsA-GSH cycle.

Determination of four forms of plasma thiol amino acids in individuals with chronic kidney disease by UPLC-MS/MS.

The study introduces a robust analytical method based on UPLC-MS/MS for quantifying thiol amino acids, including cysteine (Cys), cysteinylglycine (CG), homocysteine (Hcy), and glutathione (GSH), in their total and total free forms within human plasma. An optimized blank matrix was employed for accurate quantification of endogenous compounds. The method exhibited excellent linearity, precision, accuracy, recovery, and stability, making it highly suitable for plasma analysis. Distinct differences in plasma levels of GSH, Cys, Hcy, and CG across various forms (total, total free, native prototype, and symmetrical oxidation) were observed between healthy individuals and chronic kidney disease (CKD) patients. Comprehensive correlation and receiver operating characteristic (ROC) analyses revealed disrupted thiol amino acid metabolism in CKD, accompanied by heightened oxidative stress. Notably, various forms of Cys and Hcy correlated significantly with renal function markers and demonstrated high diagnostic efficacy in ROC evaluation, with Cys, particularly Cys (F), outperforming others. Hcy further complements Cys in assessing renal function impairment severity.

Photofate of Tetrabromobisphenol-A in the Arctic: Role of photofluence and dissolved organic matter

ABSTRACT Polybrominated diphenyl ethers (PBDEs) used in consumer goods and flame retardants have been replaced by alternatives such as tetrabromobisphenol A (TBBPA). TBBPA does not readily undergo global distal transport, but local sources still threaten aquatic ecosystems. We studied the photofate of TBBPA with a specific focus on how Arctic-derived dissolved organic matter (DOM) affects its reaction kinetics, degradation pathways and formation of photoproducts in artificial and natural sunlight. Our results corroborate earlier studies that reveal a pH-dependent trend in TBBPA’s direct photolysis with longer degradation times for its acidic form. DOM either plays no role or it slightly reduces TBBPA’s rate of photodegradation via inner-filter effects. Photolysis experiments conducted at our Arctic field site, Toolik Lake Field Station, revealed slower than anticipated degradation, which magnified the half-life significantly during in-lake experiments. Importantly, the composition of DOM was found to influence the type and distribution of TBBPA photoproducts formed, which suggests that different degradation pathways occur in the presence of DOM. These findings provide valuable insights into the intricate interplay of environmental variables that govern the fate of TBBPA in sunlit aquatic ecosystems globally.

Nucleic Acid Specificity, Cellular Localization and Reduced Toxicities of Thiazole Orange-Neomycin Conjugates.

Selective binding of small molecule ligands to nucleic acids with high affinity and limited toxicity remains an important goal in the development of compounds that can probe DNA or RNA in cells. Thiazole orange is a cell semi-permeant, fluorescent cyanine dye, with low background noise, that binds several forms of nucleic acids. However, thiazole orange can exhibit cytotoxicity when used at high concentration and/or with prolonged exposure. Neomycin is a non-fluorescent antibiotic with affinity for several forms of nucleic acids, but does not readily enter mammalian cells. Conjugation of neomycin with thiazole orange can exploit the properties of each individual compound, yielding a small molecule that could be used for nontoxic application in cellular analysis by microscopic imaging. We demonstrate that conjugation of neomycin with thiazole orange increases the cell permeability of neomycin, decreases the cytotoxicity of thiazole orange, and exhibits a greater degree of intracellular RNA targeted localization in the nucleolus, when compared to thiazole orange. Relative to thiazole orange, the conjugated compounds showed a much higher degree of stabilization of the nucleic acids as reflected in a greater denaturation temperature. Ultimately, our studies indicate that the conjugated thiazole orange-neomycin compounds can be used as an RNA targeted, less cytotoxic alternative for cellular labeling.

Management of Acid Rock Drainage Based on Geochemical Characterisation of Waste Rock Material, Study Case: Gold Mining With High Sulfidation Ephithermal (HS) Deposits

Acid rock drainage (ARD) or Acid mine drainage (AMD) is significant challenge for the global gold mining industry, necessitating specialized treatment to prevent its occurrence. Rambajoring is deposits located at the North Sumatra Martabe gold mine, the mine is an epithermal deposit of a high sulfidation system. A crucial step in management of AMD is identifying rocks that potentially produced acid water or not if contact with water and oxygen. Static testing provides an indication of the potential acidity that can be generated by rock samples based on their composition. These rocks are classified into Potentially Acid Forming (PAF) or Non-Acid Forming (NAF). Laboratory analyses including Acid Base Accounting (ABA), Net Acid Generating (NAG) Test, and paste pH, identified all lithology with uncertain category. This uncertainty occurs impact of presence of significant non-pyritic or non-acid forming sulfide sulphur mineral in this case of Alunite (KAl3SO2OH6) minerals. Containing these minerals will result in erroneously high estimations of total sulphur (S) and increasing the calculated of NAPP. Long term implication non-pyritic sulfide may oxidize slowly, leading to delayed acid generation not reflected in static NAPP calculation. Supplementary test to validation static test result and analysis geochemical behaviour of rocks using kinetic testing with Field Column Leach Test (FCLT) method. FDCLT test confirm in eight months period monitoring, all lithology have a lag time before significant acidity is produced and classified as PAF rocks. The leaching properties of material had highest concentrations of iron (Fe), cooper (Cu) and zinc (Zn). Keyword : AMD, ABA, Geochemical Characteristics, NAF, PAF, Kinetic Test, Static Test

Optimizing Silicon Application for Enhancing Growth and Chlorophyll Concentration in Pepper Plants (Piper nigrum L.) Cultivar Kuching

Silicon is known to play a central role in regulating various aspects of plant growth and development, including nutrient uptake, root formation, and growth. Silicon is the second most abundant element found in soil primarily as neutral, monomeric silicic acid, which is the biologically available form for plant uptake. Although silicon is not considered an essential nutrient for the basic life cycle of most plants, its availability can significantly benefits to plant health, growth, and stress tolerance. However, previous research has mainly focused on plants grown in silicon, and silicon occurs naturally as silicon dioxide (SiO2), and is not in a form that is easily absorbed by plants. Therefore, this study investigates the effects of silicon (Si) in silicic acid form (H4O4Si) on the growth and chlorophyll concentration of pepper (Piper nigrum L.) seedlings, particularly the Kuching variety. The Si application had been applied once a week with five different concentrations via root applications; T1 [0.5% Si (v/v)], T2 [1.5% Si (v/v)], T3 [2.0% Si (v/v)], T4 [1.5% potassium silicate (v/v)] as positive control and T5 [negative control (without silicon)] on pepper cutting-grown plants. Growth parameters such as plant height, stem diameter and chlorophyll concentration were observed and collected. Our results showed that the treatment with Si nutrients is promising, as the Si-treated pepper clones showed faster and more robust growth compared to the control plants in the early growth stages. The results indicate that a 0.5% Si concentration (v/v) effectively maintains the high chlorophyll content over four weeks, in contrast to the decreasing trend observed in the control group. This study thus presents the first report on the application of Si in P. nigrum L., demonstrating the feasibility of Si uptake and growth enhancement in pepper plants. The results suggest a stepwise application of Si, starting with low concentrations (0.5% Si v/v) via the root in the early growth stages to strengthen young plants before transplanting to the field. However, foliar spraying could also be considered in future studies as the silicon is absorbed faster compared to root application. Further studies on the passive defence structure (physical barriers such as cuticle, wax, and trichomes) are needed to prove that it can repel pathogens and insects.

Productivity Scenedesmus sp. in Various Cultivation Media

Scenedesmus sp. is one of the microalgae that is used as natural food for fish seeds or larvae. Scenedesmus sp. contains 8-56% protein, 10-52% carbohydrates, 2-40% fat, and 3-6% nucleic acid. Scenedesmus sp. also contains fatty acids in the form of lauric acid (0.22%), myrsiric acid (0.34%), linolenic acid (16.16%), glycerol trilaurate (3.73%), and vanil laurate (35.52%). Cultivation of Scenedesmus sp. can be done using inorganic fertilizer or waste water media. The types of inorganic fertilizer commonly used for cultivation are urea, KCL, TSP, Intermediate, Raja Bandeng brand. Meanwhile, waste water media can be used for cultivating Scenedesmus sp. namely tofu liquid waste water, milk waste water, bean sprout extract media, textile waste water. The results of cultivation in this media have an influence on the productivity of Scenedesmus sp.

Study on the formation mechanism and effective manipulation of polymorphs and solvates in Osimertinib-Caffeic acid multi-component crystal with distinct properties.

Investigating the formation mechanism and effective manipulation of multi-component crystal polymorphs is crucial for facilitating industrial drug development. Herein, five novel Osimertinib-caffeic acid forms were first strategically tailored by varying solvent selection. Theoretical analysis demonstrated this polymorphism is correlated with multiple hydrogen bond donors-acceptors within multi-component system, which provides manipulation space for reconfiguration of intermolecular interactions and structural competition, while solvent further induced or involved in hydrogen-bonded rearrangements. Molecular dynamics simulation and solvent characterization revealed strong solute-solvent interaction and hydrogen bond donor propensity promoted the generation of hydrate. Small molecular size or large cavity of crystal facilitated solvent entry, resulting in the generation of channel-type solvates. Higher solvation free energy implied faster reaction rate and poorer solvent removal ability for solvates. Thermal analysis confirmed removal of the solvent occupying crystal channels for precursor solvates led to polymorph formation while maintaining the structure. Properties assessments revealed multi-component crystals significantly enhanced the physicochemical properties of Osimertinib. Polymorphs and hydrate exhibited remarkable distinctions in solubility, dissolution rate and physical stability. Nanoindentation and tableting tests confirmed distinct mechanical properties of different forms. Overall, this exploration has the potential to reshape the landscape of multi-component crystal polymorph development, paving the way for manipulating intermolecular interactions.

Trema micranthum (L.) Blume as a new source of cannabinoids

Trema micranthum (Cannabaceae) has emerged as a promising new source of cannabinoids, including cannabidiol (CBD). Given the substantial medicinal demand for cannabinoids and the regulatory challenges associated with Cannabis sativa due to the presence of Δ9-tetrahydrocannabinol (THC), this study sought to explore the presence of CBD, THC, and their precursors, Δ9-tetrahydrocannabinolic acid A (THCA A) and cannabidiolic acid (CBDA), in various parts of Trema micranthum using UHPLC-HRMS/MS (Orbitrap). Extracts from fruits, leaves, inflorescences, and stems were obtained using a methanol/hexane (9:1, v/v) solvent mixture. UHPLC coupled with an Orbitrap mass spectrometer was employed for cannabinoid identification and quantification, with standard mixtures prepared in methanol. The extracts yielded significant quantities, such as 6.6%/g from leaves and 3%/g from fruits. Cannabinoids were detected in fruits, leaves, and inflorescences, with acidic forms (CBDA and THCA A) present in higher concentrations than their neutral counterparts. Notably, leaves contained 4.43 × 10−3 µg/g of CBD and 1.05 × 10−3 µg/g of THC. These findings, facilitated by high-resolution analytical methods, underscore the potential of Trema micranthum as an alternative source for cannabinoids, guiding future research in this area.

Theoretical Insight into Antioxidant Mechanism of Caffeic Acid Against Hydroperoxyl Radicals in Aqueous Medium at Different pH-Thermodynamic and Kinetic Aspects.

In this study, the DFT/M062X/PCM method was applied to investigate thermodynamic and kinetic aspects of reactions involved in possible mechanisms of antioxidant activity of caffeic acid against HOO● radicals in aqueous medium at different pH values. Kinetic parameters of the reactions involved in HAT (Hydrogen Atom Transfer), RAF (Radical Adduct Formation), and SET (Single Electron Transfer) mechanisms, including reaction energy barriers and bimolecular rate constants, were determined, and identification and characterization of stationary points along the reaction pathways within HAT and RAF mechanisms were performed. Inspection of geometrical parameters and spin densities of the radical products formed within HAT and RAF mechanisms revealed that they are stabilized by hydrogen bonding interactions and the odd electron originated through the reaction with the HOO● radical is spread over the entire molecule, resulting in significant radical stabilization. Thermodynamic and kinetic data collected in this study indicated that increasing pH of the medium boosts the antioxidant activity of caffeic acid by reducing the energy required to generate radicals within the RAF and/or HAT mechanism and, at extremely high pH, where the trianionic form of caffeic acid is a dominant species, by the occurrence of an additional fast, diffusion-limited electron-related channel.

Bacteriorhodopsin of purple membrane reverses anisotropy outside the pH range of proton pumping based on logic gate realization

The bacteriorhodopsin of purple membrane is the first discovered light-sensing protein among ion transporting microbial rhodopsins, some of which (e.g. Archaerhodopsin 3) could be broadly used as tools in optogenetics having wide potential of medical applications. Since its discovery as early as in 1971, bacteriorhodopsin has attracted wide interests in nano-biotechnology, particularly in optoelectronics devices. Therefore, the present work has been motivated due to two topics; firstly, anisotropy demand became indispensible in bioelectronics; secondly, the stationary level of electric response in bacteriorhodopsin within the pH range of proton pumping (pH 3 – pH 10) implies, in turn, raising here a question about whether the electric anisotropy is implicated for reducing (or switching off) such level beyond such pH range. Noteworthy is that the purple membrane converts to blue form upon acidification, while to reddish purple form upon alkalization. In the present study, the acidic and alkaline forms of bacteriorhodopsin have exhibited most probable state of reversal for the dielectric anisotropy around pH 2.5 and pH 10.5, respectively. This is underscored by proposing a correlation seemingly found between disassembly of the crystalline structure of bacteriorhodopsin and the reversal of dielectric anisotropy, at such acidic and alkaline reversal pH’s, in terms of the essence of the crystalline lattice. Most importantly, the results have substantiated dual frequency characteristics and logic gate-based dielectric anisotropy reversal to bacteriorhodopsin, which may implicate it for potential applications in bioelectronics.

Docosahexaenoic Acid (DHA) Supplementation in a Triglyceride Form Prevents from Polyglutamine-Induced Dysfunctions in Caenorhabditis elegans.

A common hallmark of neurodegenerative diseases is the accumulation of polypeptide aggregates in neurons. Despite the primary cause of these diseases being inherently genetic, their development can be delayed with proper preventive treatments. Long-chain polyunsaturated fatty acids (ω-3 LCPUFA) are promising bioactive nutrients that are beneficial for brain health. In this study, the impact of an oil rich in a structured form of docosahexaenoic acid (DHA) triglyceride (TG) was assessed in a Caenorhabditis elegans model expressing long poly-glutamine (polyQ) chains, which mimics the symptomatology of polyQ-related neurodegenerative diseases such as Huntington's disease (HD), among others. The lifespan, the motility, the number of polyQ aggregates, the oxidative stress resistance, and the cognitive performance associated with sensitive stimuli was measured in mutant nematodes with polyQ aggregates. Overall, DHA-TG at 0.5 µM improved the lifespan, the motility, the oxidative stress resistance, and the cognitive performance of the nematodes, emphasizing the protection against serotonergic synapse dysfunction. Furthermore, the treatment reduced the polyQ aggregates in the nematodes. The data described herein shed light on the connection between DHA and the cognitive performance in neurodegenerative diseases and demonstrated the potential of DHA-TG as nutritional co-adjuvant to prevent the development of polyQ-associated dysfunctions.

Diprotonation of taurine: 2-[dihydroxy(oxo)sulfanyliumyl]ethanaminium bis[hexafluoroarsenate(V)

Taurine is part of the cysteine cycle and is one of the few naturally occuring organosulfur-based molecules in the human body. As implied by modern studies, protonated taurine is of biological impact. The first attempts to isolate its protonated species in the binary superacidic system HF/SbF5 were performed by Hopfinger, resulting in the isolation of monoprotonated taurine. Since the chosen conditions seemed rather harsh, investigations in less acidic systems were performed at room temperature to explore the involved protonated species. Herein, we present the structure of 2-[dihydroxy(oxo)sulfanyliumyl]ethanaminium bis[hexafluoridoarsenate(V)], [H2O3SC2H4NH3][AsF6]2, the diprotonated form of 2-aminoethanesulfonic acid (taurine). It was synthesized in the binary superacidic system HF/AsF5 and crystallizes as colourless needles. Diprotonated taurine was structurally characterized by single-crystal X-ray diffraction analysis, low-temperature vibrational spectroscopy and NMR spectroscopy.

Olive solid wastes: UHPLC-MS/MS-based biochemometric approach for investigating the effect of conventional versus modern extraction methods on in vitro antioxidant, α-glucosidase, and lipase actions

The olive oil industry produces huge amounts of solid by-products (e.g., pomace, leaf, and stone), representing a rich source of polyphenols. Different extraction techniques were compared, including conventional (e.g., maceration) versus modern (e.g., microwave-, ultrasound-, and enzyme-assisted extraction), to yield a total of 17 extracts to include 2, 7, and 8 leaf, pomace, and stone extracts, respectively. Ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) combined with unsupervised and supervised modeling were employed for assessing extracts’ heterogeneity and markers identification, respectively. Verbascoside and γ-tocopherol were potentially associated with microwave- (MAE) and supercritical fluid CO2-assisted (SFE) extracts of olive pomace, respectively. Besides, hydroxylated product of the decarboxylated form of hydroxy elenolic acid (HDHEA), hydroxytyrosol, and verbascoside were correlated with antioxidant activity based on partial least squares regression (PLS) (R2 = 0.8) for pomace extracts, whereas verbascoside appeared as the strongest antioxidant marker in stone extracts. Furthermore, total phenolics (TPC) and flavonoids (TFC) were determined showing that MAE-prepared extracts exhibited the highest TPC at 72.0 and 53.6 mg GAE.g−1 dw from aqueous extracts of pomace and stone, respectively. This study identifies MAE, particularly aqueous extracts, as the most effective method for obtaining phenolic and antioxidant-rich extracts from olive by-products. The MAE not only maximizes the yield of beneficial compounds but also enhances their bioactivity. Future research should focus on conducting both in vivo assays, which shall provide deeper insights into the potential applications of olive by-products and validate the efficacy of the extraction methods employed.

Clogging of Leachate Drains in Landfills due to Biochemical Precipitation: a Literature Review

Objective: Review the relevant literature and analyze the causes that lead to the clogging of leachate drains in landfills due to biochemical precipitation. Theoretical Framework: Although leachate drainage systems have greatly evolved in terms of performance, clogging can occur in all designs due to physical, biological, and chemical mechanisms. Method: To investigate the issue of clogging in leachate drainage systems, an extensive literature review was conducted through consultations on relevant websites. National and international technical papers were sought, as well as regulations from environmental agencies of different countries. Results and Discussion: The removal of Chemical Oxygen Demand (COD), primarily in the form of acetic acid, transforms this stronger acid into weaker acids such as carbonic acid, which results in an increase in the pH of the environment. The concentration of carbonate also increases, consequently accelerating the precipitation of calcium carbonate. These precipitates are usually mixed with the biofilm and exhibit very characteristic shapes and structures. Research Implications: The lifespan of a vertical landfill can be strongly determined by the clogging phenomena in the leachate drainage system. Therefore, the monitoring of this system must be carried out with great care. Originality/Value: This review stands out for addressing a relevant and underexplored topic, especially in the national technical literature. Understanding the processes that can lead to clogging of the leachate drainage system is of interest to everyone working in the field, particularly those who design and/or operate a landfill.

Influence of Organic Matter and Speciation on the Dynamics of Trace Metal Adsorption on Microplastics in Marine Conditions.

Dissolved organic matter (DOM), primarily in the form of humic acid (HA), plays a crucial role in trace metal (TM) speciation and their subsequent adsorption dynamics on microplastics (MP) in aquatic environments. This study evaluates the impact of environmentally relevant concentrations of HA on the adsorption behaviors of essential (Co, Cu, Ni, and Zn) and toxic (Cd and Pb) TMs onto polyethylene (PE) and polypropylene (PP) pellets, as well as PP fibers under marine conditions, during a six-week experiment. The HA concentrations were 0.1, 1, and 5 mg/L, while all metals were in the same amounts (10 µg/L). Results reveal that HA significantly influences the adsorption of Cu, Pb, and Zn on MP, particularly on PP fibers, which exhibited the greatest TM adsorption dynamics. The adsorption patterns correspond to the concentrations of these metals in seawater, with the sequence for pellets being Zn > Cu > Pb > Ni > Co~Cd, and for fibers Cu > Zn > Pb > Co~Ni > Cd. Speciation modeling supported these findings, indicating that Cu, Pb, and Zn predominantly associate with HA in seawater, facilitating their adsorption on MP, whereas Cd, Co, and Ni mainly form free ions and inorganic complexes, resulting in slower adsorption dynamics. Statistical analysis confirmed the influence of HA on the adsorption of Cd, Pb, Cu, and Ni. By investigating the dynamics of TM adsorption on plastics, the influence of DOM on these two contaminants under marine conditions was evaluated. The presented results can help in forming a better understanding of synergistic plastic and trace metal pollution in marine systems that are relevant at the global level, since both contaminants pose a serious threat to aquatic ecosystems.