Search Results (111)

Cannabinoids can bind to several cannabinoid receptors and modulate cellular signaling and gene expression relevant to inflammation and lipid homeostasis. Likewise, several vitamin E analogs can modulate inflammatory signaling and foam cell formation in macrophages by antioxidant and non-antioxidant mechanisms. We analyzed the regulatory effects on the expression of genes involved in cellular lipid homeostasis (e.g., CD36/FAT cluster of differentiation/fatty acid transporter and scavenger receptor SR-B1) and inflammation (e.g., inflammatory cytokines, TNFα, IL1β) by cannabinoids (cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC)) in human THP-1 macrophages with/without co-treatment with natural alpha-tocopherol (RRR-αT), natural RRR-αTA (αTAn), and synthetic racemic all-rac-αTA (αTAr). In general, αTAr inhibited both lipid accumulation and the inflammatory response (TNFα, IL6, IL1β) more efficiently compared to αTAn. Our results suggest that induction of CD36/FAT mRNA expression after treatment with THC can be prevented, albeit incompletely, by αTA (either αTAn or αTAr) or CBD. A similar response pattern was observed with genes involved in lipid efflux (ABCA1, less with SR-B1), suggesting an imbalance between uptake, metabolism, and efflux of lipids/αTA, increasing macrophage foam cell formation. THC increased reactive oxygen species (ROS), and co-treatment with αTAn or αTAr only partially prevented this. To study the mechanisms by which inflammatory and lipid-related genes are modulated, HEK293 cells overexpressing cannabinoid receptors (CB1 or TRPV-1) were transfected with luciferase reporter plasmids containing the human CD36 promoter or response elements for transcription factors involved in its regulation (e.g., LXR and NFκB). In cells overexpressing CB1, we observed activation of NFκB by THC that was inhibited by αTAr. Full article

The present study investigates the potential of poplar (Populus spp.) biomass from phytoremediation plantations as a feedstock for downdraft fixed bed gasification. The biomass was characterized in terms of moisture, ash content, elemental composition (C, H, N, O), and calorific values (HHV and LHV), confirming its suitability for thermochemical conversion. Gasification tests yielded a volumetric syngas production of 1.79 Nm³ kg⁻¹ biomass with an average composition of H₂ 14.58 vol%, CO 16.68 vol%, and CH₄ 4.74 vol%, demonstrating energy content appropriate for both thermal and chemical applications. Alkali and alkaline earth metals (AAEM), particularly Ca (273 mg kg⁻¹) and Mg (731 mg kg⁻¹), naturally present enhanced tar reforming and promoted reactive gas formation, whereas heavy metals such as Cd (0.27 mg kg⁻¹), Pb (0.02 mg kg⁻¹), and Bi (0.01 mg kg⁻¹) were detected only in trace amounts, posing minimal environmental risk. The results indicate that poplar pruning residues from phytoremediation sites can be a renewable and sustainable energy resource, transforming a waste stream into a process input. In this perspective, the integration of soil remediation with syngas production constitutes a tangible model of circular economy, based on the efficient use of resources through the synergy between environmental remediation and the valorization and sustainable management of marginal biomass—i.e., pruning residues—generating environmental, energetic, and economic benefits along the entire value chain. Full article

Expansion of d(GGGGC)_n repeat in the C9ORF72 gene is causal for Amyotrophic Lateral Sclerosis (ALS) and Frontal Temporal Dementia (FTD). Proposed mechanisms include Repeat-Associated Non-AUG translation or the formation of G-quadruplexes (GQ) that disrupt translation, induce protein aggregation, sequester RNA processing factors, or alter RNA editing. Here, I show, using AlphaFold V3 (AF3) modeling, that the TAR DNA-binding protein (TDP-43) docks to a complex of GQ and hemin. TDP-43 methionines lie over hemin and likely squelch the generation of superoxide by the porphyrin-bound Fe. These TDP-43 methionines are frequently altered in ALS patients. Tau protein, a variant of which causes ALS, also binds to GQ and heme and positions methionines to detoxify peroxides. Full-length Tau, which is often considered prone to aggregation and a prion-like disease agent, can bind to an array composed of multiple GQs as a fully folded protein. In ALS and FTD, loss-of-function variants cause an uncompensated surplus of superoxide, which sparks neuronal cell death. In Alzheimer’s Disease (AD) patients, GQ and heme complexes bound by β-amyloid 42 (Aβ4) are also likely to generate superoxides. Collectively, these neuropathologies have proven difficult to treat. The current synthesis provides a framework for designing future therapeutics. Full article

In this study, a three-dimensional computational fluid dynamic (CFD) model was constructed and validated against experimental data. The oxygen injection methods—specifically the primary air flow and secondary air flow—were investigated. The results demonstrate that primary air flow is the dominant factor in combustion. An increase of primary air from an φ of 0.20 to 0.75 lead to a rise in combustion peak temperature from 892.17 K to 1321.02 K, while simultaneously expending the flame combustion zone and enhancing the conversion of C₁₀H₈ and CH₄. Conversely, increasing the secondary air flow from 1 L/min to 7 L/min reduced the centrally measured temperatures form 886.09 K to 856.07 K due to irregular flow patterns, which expanded the central low-temperature region. While secondary air flow promoted more uniform reactant conversion and slightly suppressed intermediate products (e.g., soot, C₆H₆), its overall effect was secondary to that of the primary air. This research reveals a critical design insight: using primary air injection to introduce oxygen into the reactor is a reasonable approach. The findings provide valuable guidance for optimizing partial oxidation burner design and operating conditions to maximize tar conversion while maintaining reactor integrity. The study also establishes a rigorously validated CFD framework for analyzing complex reacting flows in tar thermochemical conversion reactors. Full article

The physico-chemical and electrophysical properties of carbon coke obtained by coking composite mixtures of pitches isolated from coal tar coking plants of JSC “Shubarkol Komir” and “Qarmet” are investigated. The component composition of the initial resins and the obtained pitches was determined by gas–liquid chromatography methods. The purpose of this study was to identify the patterns of influence of the composition of composite mixtures of pitches isolated from coal tar coking plants of JSC “Shubarkol Komir” and “Qarmet”, as well as heat treatment parameters (temperature 800–1000 °C, duration 4–6 h), on the thermophysical and electrophysical properties of electrode coke, with the determination of optimal conditions for obtaining a material combining low ash content and high carbon content. It was found that the content of phenols and paraffins in the resin of “Shubarkol Komir” is approximately 25% of each component. It is shown that the properties of the final coke depend on the ratio of the mixed pitches (1:1, 1:2, 2:1) and coking conditions (temperature 800–1000 °C, duration 4–6 h). Optimal characteristics (minimal ash content of 0.4%, maximal carbon content of 97.75%) were achieved with a pitch ratio of 1:2 and a temperature of 1000 °C for 6 h. A specific heat capacity in the range of 298–448 K was measured calorimetrically for this sample, where a type II phase transition was detected at 373 K. Electrophysical measurements in the range of 293–483 K revealed a complex temperature dependence of the resistance characteristic of a semiconductor with two sections of a narrow band gap (~0.67 eV and ~0.55 eV). The novelty of the work consists in a comprehensive study of composite mixtures of coal tar pitches and the influence of heat treatment parameters on the formation of thermophysical and electrophysical properties of electrode coke. For the first time, signs of a type II phase transition have been identified for this type of coke material and gigantic permittivity values (up to 10⁹) have been recorded, indicating its potential as a functional carbon material. Full article

Understanding the formation mechanisms of three-phase products during biomass pyrolysis is essential for optimizing thermochemical conversion and enhancing the efficient utilization of renewable resources. In this study, wheat straw (WS) and pine sawdust (PS) were selected as representative feedstocks to investigate the thermal decomposition behavior and evolution characteristics of gas, liquid (tar), and solid (char) products during pyrolysis. Thermogravimetric analysis and kinetic modeling revealed that PS exhibited higher activation energy (75.44 kJ/mol) than WS (65.63 kJ/mol), indicating greater thermal resistance. Tar yield increased initially and then declined with temperature, peaking at 700 °C (37.79% for PS and 32.82% for WS), while the composition shifted from oxygenated compounds to polycyclic aromatic hydrocarbons as temperature rose. FTIR analysis demonstrated that most functional group transformations in char occurred below 400 °C, with aromatic structures forming above 300 °C and stabilizing beyond 700 °C. Gas product evolution showed that WS produced higher CO and H₂ yields due to its composition, with CH₄ generated in relatively lower amounts. These findings provide insights into biomass pyrolysis mechanisms and offer a theoretical basis for targeted regulation of product distributions in bioenergy applications. Full article

In order to investigate the formation pathway of hydrochar during hydrothermal carbonization (HTC) and to identify the optimal process conditions for producing high-quality pyrolysis feedstock, the effect of hydrothermal temperature (220, 250, and 280 °C) on tar and hydrochar properties were analyzed by GC-MS, XRD, XPS, FT-IR, and SEM using protein-rich brewer’s spent grain (BSG) as raw material. The results showed that aromatic compounds play a major role in tar production. Increasing hydrothermal temperature significantly enhanced volatile matter removal and consequently increased the fixed carbon content from 23.14 wt.% in HC-220 to 27.07 wt.% in HC-280, while the catalytic effect of H₃O⁺ produced by high-temperature water facilitated the dehydration and decarboxylation reactions, resulting in a reduction in the H/C atomic ratio from 1.44 in HC-220 to 1.25 in HC-280 and the O/C atom ratio from 0.32 in HC-220 to 0.25 in HC-280. HC-280 exhibited superior fuel properties, with a high heating value (HHV) of 35.4 MJ/kg. XPS analysis indicated that elevated temperatures promote the conversion of sp³ C to sp² C (the value of sp² C/sp³ C increased from 1.13 in HC-220 to 1.49 in HC-280), significantly increasing the aromatic condensation degree of hydrochar. The more pronounced reduction in the -OH content compared to -COOH indicated that dehydration reactions predominated over decarboxylation. Finally, the formation pathways of hydrochar during HTC were revealed based on the properties of different products. The results demonstrate that HTC is an effective method for converting BSG into pyrolysis feedstock with potential applications in energy production. Future work should focus on the technical–economic assessment of the process at a pilot scale and evaluating the hydrochar’s performance in real pyrolysis systems. Full article

The utilization of biomass as a renewable energy source has the potential to play a role in mitigating climate change. Furthermore, biomass gasification represents a sustainable solution for the management of lignocellulosic waste. Topics related to the different types of gasification reactors, biomass, and economic feasibility, along with tar formation and its removal in the product gas, are discussed as general aspects in the gasification. A detailed analysis of capital and operational expenditures, the net present value, the payback period, and the internal rate of return of downdraft gasifiers has been conducted. A bibliometric analysis has been conducted; the results are presented in the form of visual maps based on keywords, and likely future trends in gasification modeling were identified. Since modeling is crucial to optimize the production or quality of the syngas, this paper discloses some important aspects related to biomass gasification carried out on downdraft gasifiers. The modeling section encompasses a range of approaches, including those based on chemical equilibrium, both stoichiometric and non-stoichiometric, kinetic models, and computational fluid dynamics. A substantial section is devoted to the modeling of the downdraft reactor, incorporating the primary conservation equations for mass, energy, and momentum. The modeling framework aims to provide a comprehensive overview for researchers seeking to simulate downdraft gasifiers. This enables researchers to utilize a summary of equations and conditions that are pertinent to their own modeling and simulations. Full article

Among biomass gasification syngas cleaning methods, non-catalytic reforming emerges as a sustainable and high-efficiency alternative. This study employed integrated experimental analysis and kinetic modeling to examine non-catalytic reforming processes of biomass-derived producer gas utilizing a synthetic tar mixture containing representative model compounds: naphthalene (C₁₀H₈), toluene (C₇H₈), benzene (C₆H₆), and phenol (C₆H₅OH). The experiments were conducted using a high-temperature fixed-bed reactor under varying temperatures (1100–1500 °C) and equivalence ratios (ERs, 0.10–0.30). The results obtained from the experiment, namely the measured mole concentration of H₂, CO, CH₄, CO₂, H₂O, soot, and tar suggested that both reactor temperature and O₂ content had an important effect. Increasing the temperature significantly promotes the formation of H₂ and CO. At 1500 °C and a residence time of 0.01 s, the product gas achieved CO and H₂ concentrations of 28.02% and 34.35%, respectively, while CH₄, tar, and soot were almost entirely converted. Conversely, the addition of O₂ reduces the concentrations of H₂ and CO. Increasing ER from 0.10 to 0.20 could reduce CO from 22.25% to 16.11%, and H₂ from 13.81% to 10.54%, respectively. Experimental results were used to derive a kinetic model to accurately describe the non-catalytic reforming of producer gas. Furthermore, the maximum of the Root Mean Square Error (RMSE) and the Relative Root Mean Square Error (RRMSE) between the model predictions and experimental data are 2.42% and 11.01%, respectively. In particular, according to the kinetic model, the temperature increases predominantly accelerated endothermic reactions, including the Boudouard reaction, water gas reaction, and CH₄ steam reforming, thereby significantly enhancing CO and H₂ production. Simultaneously, O₂ content primarily influenced carbon monoxide oxidation, hydrogen oxidation, and partial carbon oxidation. Full article

Fast microwave pyrolysis technology can effectively convert brown coal into hydrogen-rich syngas. However, the unique pyrolysis behaviour of brown coal under microwave conditions is not fully understood in comparison with conventional pyrolysis. This study used Victorian brown coal as a raw material to conduct pyrolysis experiments under conventional and microwave heating methods. The results demonstrate that the microwave-assisted pyrolysis of Victorian brown coal can selectively crack polar functional groups, enhancing H₂ and CO production via radical-driven secondary reactions and gasification, while conventional heating favours the formation of tar containing phenols and fewer aromatic compounds. The result is a high-quality syngas (75.03 vol.%) with a hydrogen yield of 10.28 (mmol Gas/g Coal (daf)) at 700 °C under microwave heating, offering a scalable route for valorising low-rank coals. Full article

Polycyclic aromatic hydrocarbons (PAHs) in biochar, as opposed to those in pyrolysis liquid products that exit the reactor without adhering to the solid product, are particularly undesirable due to their environmental persistence and potential toxicity. When applied as a soil amendment, biochar containing PAHs poses risks to soil ecosystems and human health. Their formation during pyrolysis presents a significant challenge in biochar production, requiring the optimization of pyrolysis process parameters to minimize PAH content for safe soil amendment applications. This study explored the effects of particle size and heating rate on PAH formation during corn cob pyrolysis. Thermogravimetric analysis (TGA) was employed to heat corn cob powder of varying sample masses from ambient temperature to 550 °C at heating rates of 5, 10, and 20 °C/min. Simultaneously, the Chemical Reaction Engineering and Chemical Kinetics (CRECK) model simulated the pyrolysis of spherical corn cob biomass particles with a radius ranging from 1 to 40 mm, using feedstock chemical compositions as inputs. Tar species generated from the solid biomass model were introduced into a gas-phase batch reactor model to evaluate PAH formation. The results demonstrate that the particle size and heating rate significantly affect PAH formation, shedding light on the complex dynamics of biomass pyrolysis. A single spherical particle with a radius close to 1 mm approximates ideal TGA conditions by minimizing temperature and mass transfer limitations. The CRECK model suggested that a particle radius of 5–10 mm, combined with a low heating rate of 5 °C/min, optimally reduces PAH formation. Future research should focus on using thermogravimetric analysis coupled with gas chromatography–mass spectrometry (TGA-GC-MS) to comprehensively quantify PAH species formation. Full article

This study achieves the particle-resolved modeling of biomass pyrolysis via a novel approach of integrating the Discrete Element Method (DEM) with a semi-detailed chemical kinetic mechanism. By coupling CFD-DEM with a 36-step reaction network, the multiscale interactions between particle-scale hydrodynamics and the formation kinetics of 19 tar components under varying temperatures (630–770 °C) are elucidated. Levoglucosan (44.79%) and methanol (18.64%) are identified as primary tar components. Combined with these, furfural (C₅H₄O₂, 7.22%), methanal (CH₂O, 6.75%), and glutaric acid (C₅H₈O₄, 4.20%) account for over 80% of all the tar components. The secondary decomposition pathways are successfully captured, and changes in the reaction rates, as seen in triglycerides (R23: 307.30% rate increase at 770 °C) and tannins (R24: 265.41% acceleration), are quantified. This work provides the ability to predict intermediate products, offering critical insights into reactor optimization. Full article

The gasification of cellulose typically requires high temperatures (>600 °C) due to the thermal stability of levoglucosan, a major intermediate formed during pyrolysis. In this study, we investigated the gasification behavior of cellulose by combining infrared (IR) heating with low-power dielectric barrier discharge (DBD) plasma treatment. Cellulose filter paper was first pyrolyzed using localized IR irradiation (2 kW for 30 s), generating mist-like volatile products including levoglucosan. These volatiles were then exposed to DBD plasma (16–64 W for 1 or 3 min) under Ar flow. Despite the relatively low estimated gas temperatures below 240 °C in the plasma region, gas yields, including H₂ and CO, increased markedly with discharge power, reaching up to 72.6 wt% at 64 W for 3 min—more than four times that obtained with IR heating alone. These results indicate that DBD plasma facilitates the gasification of pyrolysis volatiles under significantly lower temperature conditions than those required in conventional thermal gasification. This approach may offer a route toward low-temperature biomass gasification with reduced tar, coke, and clinker formation. Full article

HIV-1 integrase (IN), an essential viral protein that catalyzes integration, also influences non-integration functions such as particle production and morphogenesis. The mechanism by which non-integration functions are mediated is not completely understood. Several factors influence these non-integration functions, including the ability of IN to bind to viral RNA. INI1 is an integrase-binding host factor that influences HIV-1 replication at multiple stages, including particle production and particle morphogenesis. IN mutants defective for binding to INI1 are also defective for particle morphogenesis, similar to RNA-binding-defective IN mutants. Studies have indicated that the highly conserved Repeat (Rpt) 1, the IN-binding domain of INI1, structurally mimics TAR RNA, and that Rpt1 and TAR RNA compete for binding to IN. Based on the RNA mimicry, we propose that INI1 may function as a “place-holder” for viral RNA to facilitate proper ribonucleoprotein complex formation required during the assembly and particle morphogenesis of the HIV-1 virus. These studies suggest that drugs that target IN/INI1 interaction may lead to dual inhibition of both IN/INI1 and IN/RNA interactions to curb HIV-1 replication. Full article

In order to determine how lanthanide ions (La, Nd, Eu, Gd, Ho, Tb, Lu) coordinate in ternary systems with alpha-hydroxy acids (glycolic acid—GA; or tartaric acid—Tar) and spermine (Spm), potentiometric studies were conducted. In addition, binary systems of metal ions with alpha-hydroxy acids were studied, as well as the possibility of non-covalent interactions between the studied ligands. This study was carried out in aqueous solutions, and the composition of the formed complexes was confirmed using computer data analysis. Using spectroscopic measurements, the inner and outer coordination spheres of the central metal ion were determined. In ternary systems, via luminescent studies, the occurrence of the so-called ‘antenna effect’ was confirmed. These studies confirmed the formation of ternary complexes in which spermine can exist in the outer coordination sphere of lanthanide ions interacting non-covalently with an alpha-hydroxy acid in the inner coordination sphere. Full article