Search Results (350)

Alkylcyclohexanes are vital components of aviation kerosene. Intramolecular H−migration of •OOQOOH radicals controls ketohydroperoxide (KHP) formation, the primary pathway responsible for low-temperature chain-branching during low−temperature oxidation. Available chemical kinetic models for alkylcyclohexanes generally lack directly computed kinetic data for H−migration reactions of •OOQOOH in cyclic fuels; relevant rate constants are commonly transferred from analogous alkane reactions, introducing systematic uncertainties in low−temperature ignition predictions. In this work, quantum chemical calculations are performed for 13 representative •OOQOOH intramolecular H−migration pathways originating from alkylcyclohexanes, covering six structural subclasses: 1,5−H−(s)(p), 1,5−H−(s)(s), 1,5−H−(t)(p), 1,5−H−(t)(s), 1,6−H−(t)(p), and 1,6−H−(t)(s). Modified Arrhenius parameters are fitted from high−pressure−limit rate constants over 500–1500 K. Further comparison between the present computed rate data and parameters adopted in existing mechanisms demonstrates that the literature values transferred from alkanes are systematically lower. Ring strain and distinct transition−state entropy originating from cyclic structures make the alkane kinetic parameters inappropriate for alkylcyclohexane systems. The kinetic parameters and lumped subclass rate rules obtained in this study provide fundamental data for improving low-temperature oxidation models of alkylcyclohexanes. Full article

The highly conserved QseB/QseC two-component system (TCS) in Glaesserella parasuis (G. parasuis) regulates gene expression, with QseC as a histidine kinase and QseB as a response regulator. This study employed data-independent acquisition (DIA) quantitative proteomics to investigate the effects of qseB deletion on bacterial morphology, proteome, and molecular regulation. Electron microscopy revealed that the ΔqseB mutant exhibited ultrastructural damage, including cell shrinkage, membrane impairment, cell wall separation, and protoplast dissolution, indicating that the loss of qseB resulted in severe compromise of cellular structural integrity. A total of 1493 proteins were identified by DIA quantitative proteomics. Fifty-five proteins were differentially expressed between the ΔqseB mutant and the wild-type strain SC1401. Among them, 24 were upregulated and 31 were downregulated. Upregulated proteins were mainly heat shock proteins (DnaK, HslV/U, ClpB), molecular chaperones (GroL, HtpG, HslO), and co-chaperone GroES, along with translation inhibitors RaiA and RsfS. These proteins participate in stress response, protein folding, and proteostasis maintenance. The downregulated proteins included QseC, LolB, CarB, ThiL, and Tgt, which are linked to TCSs, quorum sensing, and transport functions. KEGG analysis indicated that the differentially expressed proteins are involved in RNA degradation, amino acid metabolism, and ABC transporters. Protein–protein interaction (PPI) network analysis identified 10 core hub proteins, including GroEL, HslU, and QseC. These proteins may play key roles in maintaining cellular homeostasis. Integrated multi-omics analysis identified three genes (dnaK, hslU, hslO) that were differentially expressed in both transcriptomic and proteomic data. qRT-PCR results confirmed these findings. In summary, loss of qseB disrupts the QseB/QseC system. This affects stress response, metabolism, and cell structure. These changes may affect bacterial fitness and host adaptation, providing clues for understanding the pathogenic mechanisms of G. parasuis. Full article

Sleep disorders represent a growing public health concern, yet current pharmacological interventions are limited by tolerance, dependence, and rebound insomnia. This study evaluated the probiotic properties of Bifidobacterium longum B18 and its effects on pharmacologically induced sleep parameters in male Sprague–Dawley rats, focusing on tryptophan-related metabolism and gut microbiota composition. In vitro, B18 exhibited favourable probiotic characteristics, no detectable haemolytic activity, and susceptibility to all eight antimicrobials tested. In vivo, B18 significantly shortened barbital sodium-induced sleep latency and prolonged pentobarbital sodium-induced sleep duration (p < 0.05). Targeted metabolomic profiling of faeces, plasma, and hippocampus showed increased tryptophan and melatonin concentrations, whereas 5-HTP and 5-HT remained unchanged. B18 was also associated with lower Kyn/Trp ratios, although plasma Kyn concentrations were unchanged. Increased MT/5-HT ratios and elevated hippocampal AANAT levels were also observed, supporting an association with enhanced melatonin-related metabolism. Gut microbiota analysis showed higher abundances of Bifidobacterium and Lactobacillus in the B18 group than in the DZP group, together with lower Desulfovibrio abundance than in the CTR. Exploratory correlation analysis further showed positive associations of Bifidobacterium abundance with faecal tryptophan and melatonin levels and an inverse association with the Kyn/Trp ratio. Collectively, these findings indicate that B. longum B18 modifies pharmacologically induced sleep parameters in association with altered tryptophan–melatonin metabolism and gut microbiota composition, supporting further evaluation of B18 as a candidate probiotic for sleep-related functional applications. Full article

Background/Objectives: Periodontal and peri-implant diseases are influenced by several risk factors, including smoking. While cigarette smoking (CS) is a well-established risk factor, the impact of heated tobacco products (HTPs), electronic cigarettes (E-Cigs), and waterpipe (WS) remains less clear. This systematic review aimed to update the current evidence evaluating the clinical, radiographical, and inflammatory biomarkers of periodontal and peri-implant status among different untreated adult users of inhaled tobacco and nicotine products. Methods: A systematic search of PubMed/MEDLINE, Scopus, and Cochrane Library was performed for studies published between April 2022 and December 2025. Data were extracted and synthesized qualitatively according to the study protocol (PROSPERO: CRD420261284851). Studies were qualitatively assessed using the Risk-of-Bias in Nonrandomized-I. Results: Thirty-one studies including 3106 subjects were analyzed. CS consistently showed the worst periodontal and peri-implant status, with higher plaque indices, probing depth (PD), clinical attachment level (CAL), marginal bone loss (MBL) and more missing teeth. WS showed parameters comparable to CS and worse than non-smokers, with particularly high plaque accumulation and probing depth, as well as a pro-inflammatory biomarker profile. E-Cigs and HTPs generally exhibited intermediate status; E-Cigs showed increased PD and CAL compared with non-smokers, with elevated bleeding on probing despite a lower gingival index, whereas MBL was notably higher, showing the highest overall values among all smoking categories, exceeding CS. HTPs presented slightly less harmful outcomes than other smokers, but the evidence was limited. Biomarker analysis indicated elevated pro-inflammatory and tissue-destructive markers, particularly in CS and WS. Conclusions: Smoking negatively affects periodontal and peri-implant status, with CS exhibiting the worst impact. E-Cigs and HTPs appear less harmful but are not risk-free. Longitudinal studies are warranted to define long-term effects, particularly on peri-implant status, for which robust evidence was restricted to CS. Full article

Piano key weirs (PKWs) increase the effective crest length and provide high discharge capacity within limited spillway widths; however, their hydraulic efficiency depends on key geometry. Addressing the limited understanding of key-curvature effects, this study systematically investigates the influence of inlet- and outlet-key curvature on the discharge coefficient (C_d) and crest-wise discharge distribution of type-A PKWs. Nine configurations are examined experimentally in a flume at the Hydraulics Research Institute, Egypt. These include a reference model with linear inlet and outlet keys and modified geometries incorporating C- and S-shaped keys in both normal and inverted forms. Experiments are conducted under free-flow conditions for total-head ratios H_T/P up to 0.23, where H_T is the total upstream head above the crest and P is the PKW height. A three-dimensional numerical model using FLOW-3D HYDRO is validated against these experimental data and subsequently extended to H_T/P ≈ 0.50–0.60. All reported results and conclusions are based on the numerical simulations over the full investigated range. Results show that C_d increases to a peak near H_T/P ≈ 0.08 and then decreases gradually for all configurations. Both inlet- and outlet-key curvature influence hydraulic performance by modifying flow guidance and redistribution along the crest. However, only the inverted C-shaped inlet configuration (M2) improves efficiency, increasing C_d by about 5.46% on average over the investigated head range and enhancing the total discharge by approximately 4.36% at H_T/P ≈ 0.12 relative to the reference case. Discharge-distribution analysis indicates that this improvement results from inlet feeding and efficient flow conveyance along the sidewall crest. A predictive relation is developed for the optimal configuration to support hydraulic design. Full article

Background and Objectives: Tobacco smoking is associated with an increased risk of depression and anxiety symptoms, but it remains unclear whether this relationship differs according to the type of nicotine product used. The increasing popularity of heated tobacco products has created a need to better understand their association with mental health, particularly in comparison with combustible cigarettes. Therefore, this study aimed to compare the prevalence of depression and anxiety symptoms among combustible cigarette (CC) users, heated tobacco product (HTP) users, and non-smokers. Materials and Methods: A cross-sectional study was conducted among 497 adults. Participants were classified into three groups according to their tobacco-use status: combustible cigarette smokers, heated tobacco users, and non-smokers. Depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9), and anxiety symptoms were assessed using the Generalized Anxiety Disorder-7 (GAD-7). Group differences were evaluated using hierarchical linear regression analyses adjusted for sociodemographic, health, and lifestyle factors. Results: Tobacco-use group significantly improved the model fit for PHQ-9 (ΔR² = 0.0575, p < 0.001) and GAD-7 (ΔR² = 0.0764, p < 0.001). In non-smokers, scores of depression were 3.48 lower than in CC users and 1.42 lower than in the HTP users’ group. In HTP users, these scores were 2.06 lower than in the CC users’ group. Anxiety scores were 3.71 lower in non-smokers than in CC users, and 1.29 lower than in the HTP users’ group. In the HTP users’ group, this score was 2.42 lower than in the CC users’ group. HC3 robust standard errors with 5000-sample BCa bootstrap confidence intervals and reduced-adjustment sensitivity analyses confirmed the primary pattern. Conclusions: Our study results showed that combustible cigarette users had the highest adjusted depression and anxiety scores, HTP users had intermediate scores, and non-smokers had the lowest. In both tobacco-using groups, greater product-specific nicotine dependence was associated with higher PHQ-9 and GAD-7 scores. Further interdisciplinary studies incorporating biomarkers of nicotine exposure, HPA axis function, inflammation, and oxidative stress are needed to clarify whether the observed differences reflect the characteristics of individuals who choose specific tobacco products or are partly attributable to product-specific effects. Full article

Photosynthesis is the fundamental biological process underlying plant growth, crop productivity, and global food security. However, its efficiency is highly vulnerable to abiotic stresses, which disrupt chlorophyll biosynthesis, electron transport, carbon assimilation, stomatal regulation, and photoprotective mechanisms, ultimately reducing crop yield. Improving photosynthetic resilience under adverse environments has therefore become a major objective of modern crop improvement. Recent advances in phenomics and high-throughput phenotyping (HTP) have transformed the evaluation of photosynthesis-related traits by enabling rapid, non-destructive, and large-scale assessment across diverse environments, while facilitating quantitative characterization of structural, physiological, biochemical, and thermal responses to abiotic stress. Technologies including chlorophyll fluorescence, gas-exchange analysis, thermal imaging, hyperspectral imaging, LiDAR, and UAV-based sensing provide comprehensive insights into plant physiological responses and stress adaptation. Integration of these phenomic approaches with genomic information and artificial intelligence (AI)-driven analytical frameworks has strengthened genomic and phenomic prediction, enabling more accurate identification of candidate genes, selection of superior genotypes, and accelerated genetic gain. This review critically synthesizes recent advances in photosynthesis-related traits, phenomics, HTP technologies, and their integration with genomics and AI-assisted breeding, highlighting current challenges, knowledge gaps, and future opportunities for developing climate-resilient wheat and rice cultivars and promoting sustainable crop production. Full article

Decarbonizing the process heat required for chemical recycling would improve the environmental performance of plastic-waste valorization. This study presents an evaluation of the use of concentrated solar thermal energy as the reaction heat source for the hydrothermal depolymerization of post-consumer polyethylene terephthalate (PET). The solar-driven hydrothermal process (HTP-S) maintained an internal reactor temperature of approximately 200 °C for 4 h under favorable irradiance conditions. During the single experimental run, the system received 14.95 MJ of incident solar energy, whereas the conventional hydrothermal process (HTP-C) consumed 47.52 MJ of electricity per run. Starting from 1.2 g of PET, HTP-C and HTP-S produced 0.862 and 0.895 g of dry recovered solid, corresponding to recovered-solid yields of 71.7% and 74.5%, respectively. Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis and derivative thermogravimetry (TGA/DTG), transmission electron microscopy (TEM), and X-ray diffraction (XRD) showed that the recovered solids exhibit physicochemical characteristics consistent with the formation of a crystalline terephthalic acid (TPA)-rich product. A cradle-to-gate life cycle assessment normalized to 1 kg of treated PET showed that cumulative energy demand decreased from 44,383.7 MJ for HTP-C to 7342.5 MJ for HTP-S, while global warming impacts decreased from 9717 to 1607 kg CO₂-eq. These results demonstrate the technical feasibility of coupling concentrated solar heating with hydrothermal PET depolymerization and identify reaction heating as the principal opportunity for reducing external electricity demand. These outcomes indicate that solar-powered hydrothermal processing provides a feasible pathway for PET recycling, reducing the environmental footprint. Full article

This study presents a gate-to-gate life cycle assessment (LCA) comparing the environmental impact of three torrefied municipal solid waste (MSW) energy sources (S1) solar photovoltaic (PV), (S2) grid electricity from India and (S3) biomass combustion. Experiments performed in a laboratory setting produced a yield of transitory MSW torrefaction of 28–32% at an input fuel energy of 2 kWh/kg at 200–300 °C for 30–60 min. The ReCiPe 2016 midpoints [Global Warming Potential (GWP); Human Toxicity Potential (HTP); Acidification Potential (AP); Particulate Matter Formation Potential (PMFP)] showed PV produced the least number of emissions (GWP = 0.0426 kg CO₂ equivalent; HTP = 0.00988 kg 1,4-DB equivalent), while grid power produced the greatest number of emissions (GWP = 2.2 kg CO₂ equivalent). Biomass produced intermediate results (GWP = 1.546 kg CO₂ equivalent). All sources had an average positive net energy ratio of approximately 2.78. The results indicate that integrating renewable energy sources significantly increases the environmental and social benefits of the torrefaction process. Additionally, the study provides a MS Excel-Based LCA framework to use when data are limited. Full article

Objectives: Insomnia is a highly prevalent sleep disorder involving complex neurochem-ical dysregulation; however, the spatial distribution of neurotransmitters and small-molecule metabolites across distinct brain microregions in the insomniac state re-mains poorly characterized. This study aimed to map region-specific metabolic perturba-tions in situ in a p-chlorophenylalanine (PCPA)-induced insomnia rat model using opti-mized matrix-assisted laser desorption/ionization mass spectrometry imaging (MAL-DI-MSI) integrated with targeted metabolomics validation. Methods: On-tissue chemical derivatization MALDI-MSI was optimized using α-cyano-4-hydroxycinnamic acid (CHCA) as the matrix on a Bruker tims TOF flex mass spectrometer. The rats received PCPA (400 mg/kg, intraperitoneal) for three days to establish the insomnia model. Metabolite identifi-cation was conducted using MetaboScape® software (2020b) and the Human Metabolome Database. Ultra-performance liquid chromatography–tandem mass spectrometry was em-ployed to quantify nine key neurotransmitters and metabolites across six brain microre-gions. Key synthetic enzyme expression was evaluated by immunofluorescence and West-ern blotting analyses. Results: TMP-TFB-derived brain slices clearly showed the distribu-tion of neurotransmitters in brain microregions. MALDI-MSI demonstrated that the spatial distribution and abundance of eight neurotransmitters were disturbed in brains of PCPA-induced insomniac rats. A total of 346 metabolites were characterized across six brain microregions (cerebellum, cortex, hippocampus, brainstem, hypothalamus, and stri-atum), with principal coordinate analysis revealing clear metabolic separation between control and insomniac rats. PCPA treatment markedly disrupted tryptophan and tyrosine metabolism, evidenced by decreased 5-HT, 5-HTP, and 5-HIAA, alongside region-specific alterations in DA, NE, HVA, and Ach. Additionally, GABA levels decreased in the hippo-campus, striatum, and hypothalamus, whereas glutamate increased throughout the brain. Targeted metabolomics validated the MSI findings, and Bland–Altman analysis confirmed good consistency between the two analytical platforms. PCPA further disturbed the meta-bolic enzymes MAOA, DDC, and TPH2 within the Trp-5-HTP-5-HT-5-HIAA metabolic pathway in the brainstem and TYH and DBA within the tyrosine-DA-NE metabolic pathway in the striatum. Conclusions: This study demonstrates that region-specific altera-tions in tryptophan and tyrosine metabolism pathways provide mechanistic insights into insomnia pathogenesis and potential therapeutic targets. Full article

Nutrient supplementation may enhance muscle growth by supporting myogenic activity and regulating metabolic pathways involved in skeletal muscle development. However, the effect of specific nutrient supplementation on satellite cell (SC) activity and muscle-related metabolic pathways remains unclear. Two experiments were conducted to investigate dietary supplements, including guanidinoacetic acid (GAA), 5-hydroxytryptophan (5-HTP), and quercetin, on SC proliferation and differentiation in vitro and on muscle growth and transcriptomics in vivo. For the in vitro study, ovine SC were cultured with different levels (0, 12.5, 25, and 50 μmol/L) of 5-HTP, GAA, or quercetin to examine SC proliferation and differentiation. SC proliferation was greater with 5-HTP and quercetin supplementation, whereas GAA increased SC differentiation. Based on these results, 5-HTP and GAA were selected for the in vivo study because they increased proliferation and differentiation, respectively, and had a wider range of dose effectiveness (12.5 and 25 μmol/L). For the in vivo study, Texel lambs (n = 15; 33 ± 6 kg) were blocked by weight and assigned to one of three treatments: control, GAA, or 5-HTP for 28 d. Supplements were administered sublingually at a dose of 2.5 mg/kg body weight daily before feeding. GAA or 5-HTP did not influence (p > 0.05) average daily gain or dry matter intake. Longissimus muscle area was greater (p < 0.05) at the end of the study compared to the start for all treatment groups. mRNA sequencing showed that GAA supplementation altered gene expression (Padj < 0.05) compared to the control or 5-HTP. However, 5-HTP did not affect (p > 0.05) gene expression compared to the control. LC-MS also showed that plasma 5-hydroxyindoleacetic acid (5-HIAA) was elevated (p < 0.05) in the 5-HTP group. The results suggest that these dietary supplements can stimulate SC proliferation or differentiation in vitro. Short-term supplementation of GAA or 5-HTP in vivo did not alter growth performance, muscle mass, or miR-133a expression; however, GAA supplementation altered the transcriptome to promote amino acid metabolism pathways that are commonly linked to muscle growth through muscle protein synthesis and energy metabolism. Full article

Traditional hypergolic propellants, such as hydrazine derivatives combined with nitrogen tetroxide, present severe toxicity, operational, and environmental hazards. High-test peroxide has emerged as a leading green oxidiser replacement due to its low volatility, high density, and benign decomposition products. This review comprehensively analyses recent advancements in HTP-based hypergolic fuel formulations, categorising them into three major emerging families: catalytically-promoted, reactive, and ionic liquid-based systems. By evaluating key parameters such as ignition delay times, specific impulse and toxicity, this work identifies a clear technological shift from fundamental chemical screening to increasingly more mature solutions. While historical targets defined hypergolicity below 100 ms, recent advanced formulations routinely achieve it under 10 ms requiring minimal additive concentrations (<5 wt%), directly competing with legacy systems. Furthermore, this review highlights critical open challenges that limit commercial adoption, including the long-term storage stability of catalytic blends, high toxicity of reactive systems, and the lifecycle toxicity and high cost of frequently employed ionic liquids. Ultimately, it is concluded that rather than a single universal replacement, the future of green hypergolic propulsion lies in a plurality of solution, where each family is tailored to specific niches defined by mission requirements and cost structures. Full article

Heated tobacco products (HTPs) generate an inhalable aerosol by heating tobacco instead of burning it as conventional cigarettes do. Although several harmful and potentially harmful constituents (HPHCs) are generally reduced compared with conventional cigarette smoke, the World Health Organization’s list of nine priority toxicants (WHO 9) may not fully reflect the chemical complexity of HTP aerosols. The main goal of this review is to evaluate the occurrence, quantitative levels, and toxicological relevance of HPHCs identified in IQOS aerosols and to propose an expanded toxicant panel for aerosol characterization. The review was conducted according to PRISMA 2020 recommendations using literature retrieved from the Web of Science Core Collection database. The studies included in the present review consistently report lower levels of many combustion-related toxicants in IQOS aerosols, compared with conventional cigarette smoke, particularly for carbon monoxide, volatile organic compounds, and polycyclic aromatic hydrocarbons. However, several toxicologically relevant compounds, including carbonyls, tobacco-specific nitrosamines, phenolics, and trace metals, remained detectable in several studies. An expanded panel of twenty priority toxicants was proposed, based on toxicological relevance, frequency of detection, regulatory significance, and analytical feasibility. The proposed panel extends beyond the WHO 9 framework while preserving regulatory applicability and analytical practicality. The findings support the need for harmonized methodologies and broader toxicant monitoring strategies for the comparative assessment of heated tobacco products. Full article

Background: Secondhand exposure to heated tobacco products (HTPs) is increasingly common, but its impact on human milk composition is unclear. We investigated whether secondhand exposure to HTP aerosols affects major human milk components and cotinine concentrations in lactating women. Methods: This observational study included 15 lactating women whose household members used HTPs (secondhand HTP exposure group) and 33 lactating women who did not live with any smokers (non-exposed group). Human milk was analyzed for macronutrients, total solids, energy, lactoferrin, secretory immunoglobulin A (sIgA), calcium, inorganic phosphorus, zinc, and cotinine. Cotinine was measured in all women in the secondhand HTP exposure group and in three women in the non-exposed group. Results: Background characteristics did not differ significantly between groups. No significant differences were observed in lipid, protein, total solids, energy, true protein, lactoferrin, calcium, inorganic phosphorus, or zinc. Carbohydrate concentration differed significantly between the non-exposed and secondhand HTP exposure groups (non-exposed vs. secondhand HTP exposure: 8.20 vs. 8.10 g/dL, p = 0.032), although the absolute difference was small. sIgA tended to be higher in the secondhand HTP exposure group (non-exposed vs. secondhand HTP exposure: 1244 vs. 1706 μg/mL, p = 0.072). Cotinine concentrations did not differ significantly between groups; qualitative cotinine tests were negative in all samples. Conclusions: Secondhand exposure to HTPs was not associated with clear differences in major human milk components or cotinine concentrations. However, the findings should be interpreted cautiously because of the small sample size and limited cotinine assessment. Larger studies with objective exposure assessment and infant follow-up are needed. Full article

Background/Objectives: Aromatic L-amino acid decarboxylase deficiency (AADC-D; OMIM #608643) is a rare autosomal recessive neurometabolic disorder caused by pathogenic variants in the DDC gene, leading to impaired of monoamine neurotransmitter biosynthesis. AADC, a pyridoxal-5′-phosphate (PLP)-dependent enzyme, catalyzes the conversion of L-dopa and 5-hydroxytryptophan (5-HTP) to dopamine and serotonin, respectively. Early diagnosis remains challenging due to the limited specificity of current biochemical approaches. This study aimed to evaluate plasma AADC enzyme activity using these physiological substrates by High-Performance Liquid Chromatography (HPLC)-based method and assess its potential utility in the biochemical diagnosis of AADC deficiency. Methods: Plasma AADC activity was quantified using physiological substrates (L-dopa and 5-HTP) by HPLC with electrochemical and fluorescence detection. Sanger sequencing of the DDC gene was performed in two suspected patients to identify pathogenic variants. Results: Two genetically confirmed AADC-D patients demonstrated reduced enzyme activity. Using L-dopa as substrate, enzyme activity in patients was 12.4 and 26.1 pmol/min/mL, both below the published reference interval (36–129 pmol/min/mL). Using 5-HTP as substrate, enzyme activity was 1.5 and 5.1 pmol/min/mL; Patient 1 showed activity below the reference interval (2.0–7.1 pmol/min/mL), while Patient 2 demonstrated activity within the lower range of reported values. Reduced enzyme activity was consistent with the clinical features and molecular findings with identification of pathogenic variants in the DDC gene (c.175G>A and c.714+4A>T). Conclusions: Plasma AADC activity measurement demonstrates potential as a functional biochemical biomarker that augments molecular genetic testing in the biochemical evaluation of AADC deficiency. Further studies involving larger patient cohorts are required to further evaluate its diagnostic performance and broader clinical applicability. Full article