Search Results (13,117)

Ketone bodies (KBs) are the only energy substrates oxidized by the brain, whose concentration in the circulation can greatly increase when a physiological situation requires it. For example, when an adult human fasts for two days, circulating KBs rise twenty-fold from ~0.1 to ~2 mM. As a fuel, KBs provide the brain with acetyl-CoA that produces ATP or glutamate, notably in certain brain regions. Remarkably, KBs activate the expression of their own cerebral transporters and KB-utilizing enzymes so that circulating levels determine cerebral utilization of KBs. Throughout evolution, the energetic role of KBs has been crucial for the metabolic homeostasis of humans endowed with a large brain and facing unpredictable periods of food shortage. Paradoxically, the brain of modern, regularly fed humans whose ordinary blood KBs are ~0.1 mM, has access to much fewer circulating sources of energy than that of their distant ancestors. KBs can modify certain proteins post-translationally, for example, histones through lysine-butyrylation. KBs could act as short- or long-term epigenetic messengers. These properties of KBs might allow a fetus to directly sense maternal starvation and adapt their cerebral metabolism to this situation, possibly preparing for nutritional constraints in extra-uterine life. KB transcriptional and epigenetic properties could also enable the postnatal organism to retain a molecular memory of its own starvation episodes. No other energy substrate, such as glucose or lactate, has such capacities. Medicine turned its attention to KBs a century ago. Indeed, KBs are the only energy substrates whose circulating levels can be increased, and nutritional interventions can alter them under free-living conditions. This property opens broad prospects for ketogenic diets (KDs) to prevent or rescue neurodegenerative diseases characterized by glucose hypometabolism, notably Alzheimer’s disease (AD). However, KDs have not yet found real medical applications, for reasons that are discussed. Full article

Accurate prediction of spring phenology is critical for understanding ecosystem carbon and water dynamics under changing climates. In this study, we applied a revised optimality-based model (R-OPT) that integrates a mechanistic photosynthesis framework into the existing OPT model to simulate leaf unfolding date. We evaluated R-OPT alongside three widely used models—Growing Degree Days (GDD), Chilling–Forcing Trade-off (CFT), and Optimality-based (OPT) models—across multiple Plant Functional Types (PFTs) and sites using repeated 5-fold cross-validation. Findings reveal that R-OPT consistently outperforms the other models, achieving the lowest median RMSE (13.11 days), indicating enhanced predictive accuracy and explanatory power. Although the model incurs slightly higher complexity (median AIC = 13.44), the improvement in prediction justifies the trade-off. Our results highlight the importance of incorporating plant functional traits and environmental heterogeneity in phenological modeling. PFT-specific differences, such as the lower RMSEs for evergreen forbs and deciduous broadleaf PFTs versus larger uncertainties for drought-deciduous and semi-evergreen PFTs, underscore that current models may insufficiently capture key environmental drivers, including precipitation and partial leaf retention. Latitudinal and elevational variations in trade-off parameter a, and the prominence of leaf-level carbon assimilation traits (Aleaf) as drivers of phenology, demonstrate the critical role of physiological traits in shaping PFT-specific phenological timing. These findings have significant implications for large-scale ecosystem modeling. By linking phenology directly to photosynthetic processes, R-OPT enhances predictive skill and biological interpretability, supporting improved simulations of carbon and water fluxes. Overall, R-OPT offers a mechanistically grounded and robust framework for advancing predictive understanding of spring phenology and its ecological and climate-relevant consequences. Full article

Dry eye disease (DED) has increasingly been linked to oxidative stress; however, the specific redox mechanisms underlying different clinical phenotypes remain incompletely understood. This study aimed to evaluate tear film oxidative stress profiles in patients with primary DED and sarcoidosis-associated DED (S-DED) by assessing lipid peroxidation, antioxidant enzyme activity, and total tear protein content, and to explore their relationship with clinical tear film dysfunction. Tear samples were analyzed for superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, as well as for malondialdehyde (MDA) and total protein levels, alongside standard clinical tests of tear film stability and secretion. Both DED groups exhibited significant oxidative alterations compared to controls, but with distinct redox signatures. Primary DED was characterized by markedly increased tear MDA levels, indicating predominant lipid peroxidation, whereas S-DED showed a more pronounced impairment of antioxidant defense, reflected by preserved or increased SOD activity in the context of significantly reduced GPx activity. Total tear protein levels were reduced in both groups, with evidence suggesting qualitative protein alterations in S-DED. The tear collection method significantly influenced the measured levels of several oxidative stress markers, underscoring the importance of sampling technique when interpreting tear-based redox profiles. Oxidative stress markers correlated with clinical measures of tear film dysfunction, supporting their physiological relevance. These findings demonstrate that DED encompasses heterogeneous oxidative stress mechanisms and that sarcoidosis acts as a modifier of ocular surface redox homeostasis. Distinct tear-based redox profiles differentiate primary from sarcoidosis-associated dry eye, highlighting the potential value of oxidative biomarkers for phenotyping DED beyond tear deficiency alone. Full article

Bioactive peptide coatings modulate cell–implant interactions on TiO₂ surfaces; however, most molecular-level studies of peptide adsorption are performed under low or fixed ionic conditions. Physiological environments exhibit non-negligible and variable electrolyte concentrations, so understanding ionic strength effects is crucial for designing effective peptide-functionalized titanium implants. An amorphous TiO₂ surface was generated from a crystalline rutile precursor and simulated in explicit water using classical molecular dynamics at nine NaCl concentrations. For each condition, seven independent simulations with different initial peptide placements/orientations were performed. Peptide backbone RMSD, minimum peptide–surface distance, and adsorption time ratio were analysed as functions of NaCl concentration. For both peptides, backbone RMSD remained stable and showed no statistically significant correlation with NaCl concentration. KRSR exhibited a significant increase in minimum distance with increasing NaCl concentration and a significant decrease in adsorption time ratio, indicating reduced persistence of close surface contact at higher salt levels. In contrast, RGD showed no significant dependence of either minimum distance or adsorption time ratio within the tested range. Within the limits of the applied force-field MD framework and the investigated NaCl range, KRSR adsorption on TiO₂ is more sensitive to ionic strength than RGD, consistent with the stronger electrostatic contribution for the net-positively charged KRSR motif. Full article

The objective of this study was to evaluate the effects of hydrogel polymer application on the antioxidant activity and physiological performance of colored-fiber cotton cultivars grown under different levels of water restriction. Two experiments were conducted under greenhouse conditions. In the first experiment, the effects of the hydrogel polymer, cultivars, and irrigation replacement levels were evaluated; in the second, the residual effect of the hydrogel polymer applied in the first experiment was assessed using the same cultivars and irrigation depths. Water restriction negatively affected relative water content, gas exchange, chlorophyll a fluorescence, and antioxidant activity, and increased electrolyte leakage in cotton cultivars. Water deficit reduced relative water content, gas exchange, chlorophyll a fluorescence, and antioxidant activity, while increasing electrolyte leakage in the cultivars. However, hydrogel polymer application up to 6.5 g dm⁻³ of soil and its residual effect in subsequent cycles were beneficial. The polymer increased relative water content and antioxidant activity, in addition to improving gas exchange and chlorophyll fluorescence, suggesting maintenance of plant physiological health. Residual polymer doses also enhanced relative water content, antioxidant activity, gas exchange, and chlorophyll fluorescence in plants during Experiment II. Full article

Dietary fiber (DF) is a fundamental component of animal nutrition and has been widely studied for its nutritional and physiological functions in animals. While existing studies mainly focus on the independent effects of DF on gut microbiota or bile acids (BAs), the mechanisms underlying their interactions remain poorly understood. DF interacts closely with gut microbiota, promoting the production of beneficial metabolites such as short-chain fatty acids, which subsequently influence BA metabolism through microbial deconjugation and dehydroxylation processes, generating free and secondary BA essential for host health. Together, the gut microbiota and BA play key roles in mediating the effects of DF on intestinal and systemic physiology via the gut–liver axis. Although DF contributes to energy supply, nutrient digestion, and regulation of gut microbiota and BA metabolism, its physiological effects vary depending on fiber source, type, chemical composition, inclusion level, and animal species. Ruminant and non-ruminant animals differ in their capacity to utilize DF, with extensive fermentation occurring in the rumen of ruminants, whereas fermentation in non-ruminants mainly occurs in the hindgut and is more limited. Consequently, inappropriate DF supplementation may impair gastrointestinal function and overall physiological status. This review summarizes the diverse effects of different DF types in animals and critically examines the complex and bidirectional interactions among DF, gut microbiota, and BA metabolism, highlighting knowledge gaps that require further investigation to optimize DF application in animal nutrition. Full article

Agrivoltaic Systems (AV) constitute a viable alternative to mitigate land-use competition by enabling the simultaneous production of agricultural crops and solar photovoltaic energy. However, the heterogeneous shading and microclimatic modifications induced by AV systems can alter solar radiation, crop physiological performance, and, consequently, its biomass. This study evaluated the effects of two static ground-mounted AV systems—semi-transparent (ST) and conventional opaque (CON) panels—on the growth, physiology, soil water variations, and yield of Arugula (Eruca vesicaria) cultivated in southern Italy from August to October 2022; compared with an open-field control (REF). Daily soil temperature and water content were monitored, alongside leaf-level gas exchange measurements at three vegetative stages. Global solar radiation was reduced by 70% under ST and 80% under CON, reducing Photosynthetically Active Radiation (PAR), transpiration, and net photosynthesis, while leaf water use efficiency remained comparable to REF. Sequential harvests showed that although yields were consistently highest in REF, ST 50% and CON 50% exhibited partial recovery in fresh and dry biomass by the third cutting, reflecting the mitigating effect of seasonal temperature declines on shading. Notably, soil water uniformity improved under AV systems, reaching 90% under ST and 94% under CON compared with 85% in REF, due to reduced evaporative losses and enhanced lateral soil water redistribution. Overall, while AV-induced shading limits radiation and yield in short-cycle leafy arugula, microclimate modulation under AV systems can enhance soil water distribution and partially buffer growth under less favorable seasonal conditions. These findings highlight the trade-offs between crop productivity and resource-use efficiency in AV systems and emphasize the importance of tailoring their design to crop type and local climatic conditions, providing valuable guidance for future experimental research and for policymakers aiming to support sustainable agrivoltaic deployment. Full article

Rapid eye movement (REM) sleep is increasingly understood as a heterogeneous state composed of two neurophysiologically distinct microstates: tonic REM and phasic REM. Phasic REM, defined by brief clusters of saccadic eye movements and transient cortical activation, has been linked to emotional memory consolidation, sensorimotor integration, and autonomic modulation. Despite its importance, automated quantification of phasic versus tonic REM remains uncommon, mainly because existing electrooculography (EOG) methods rely on fixed thresholds or generic wavelet families that do not accurately capture real saccade morphology in clinical polysomnography (PSG). This study introduces a fully automated framework for detecting phasic REM based on hybrid adaptive segmentation of a single EOG channel. The segmentation algorithm fuses median absolute deviation (MAD) amplitude-change detection with a morphology score derived from a custom saccade kernel built from manually verified EyeCon recordings. Segment boundaries are refined using local derivative extrema to improve temporal alignment. A supervised support vector machine (SVM) classifier further refines segment labels using features based on saccade morphology, including correlations with custom log-sigmoid templates and a morphology similarity measure. All segmentation and classification hyperparameters were optimized exclusively on controlled EyeCon datasets with precise ground-truth event markers. The final model was then applied without modification to 21 full-night clinical PSG recordings. Event-level analysis on EyeCon yielded 92.9% correct detections, with 5.3% fragmentation and 1.8% missed events. When aggregated into saccadic bursts, the resulting REM microstructure was physiologically consistent: phasic REM accounted for 31.8 ± 3.5% of REM duration, and tonic REM for 68.2 ± 3.5%. Additional EEG analysis confirmed increased beta and gamma power during phasic REM, supporting physiological validity. The proposed framework provides an interpretable, morphology-aware, and computationally efficient tool for large-scale REM microstructure research. Its single-channel design and external validation on clinical PSG recordings make it suitable for both retrospective analyses and future clinical applications. Full article

Background: Dyspnea is a frequent complaint during pregnancy and is often considered a benign physiological finding; however, it may also reflect underlying subclinical cardiovascular alterations. Pregnancy-related vascular remodeling and low-grade systemic inflammation may contribute to changes in aortic elastic properties and inflammatory biomarkers, particularly in symptomatic women. Objective: This study aimed to compare aortic elastic properties and albumin-based inflammatory indices between dyspneic and asymptomatic third-trimester pregnant women. A secondary aim was to establish reference values for echocardiographic and biomarker parameters in dyspneic pregnancy. Methods: In this prospective observational study, third-trimester pregnant women (≥27 gestational weeks) presenting to the emergency department (ED) with dyspnea were consecutively enrolled and compared with age-matched asymptomatic pregnant controls. Demographic, laboratory, and echocardiographic data were recorded. Aortic strain, aortic distensibility, and aortic stiffness were calculated using transthoracic echocardiography. Albumin-based inflammatory indices, including the hemoglobin–albumin–lymphocyte–platelet (HALP) score, prognostic nutritional index (PNI), C-reactive protein-to-albumin ratio (CAR), and RDW-to-albumin ratio (RAR), were analyzed. Receiver operating characteristic (ROC) and correlation analyses were performed. Results: A total of 241 pregnant women were included (121 dyspneic, 120 controls). Demographic characteristics were comparable between groups. Dyspneic pregnant women exhibited significantly lower aortic strain and aortic distensibility and higher aortic stiffness compared with controls (for all p < 0.05). Among laboratory parameters, CAR levels were significantly elevated in the dyspneic group (p < 0.001), whereas HALP, PNI, and RAR did not differ significantly. After adjustment for potential confounders, differences in aortic elastic properties remained significant. CAR demonstrated moderate discriminative ability for dyspnea (AUC = 0.692), while aortic elastic parameters showed modest predictive performance. In combined prediction models incorporating CAR with echocardiographic parameters, discriminatory performance improved, with area under the curve values exceeding 0.70. Weak positive correlations were observed between PNI and aortic strain and distensibility. Conclusions: Dyspneic third-trimester pregnant women exhibit impaired aortic elastic properties and increased CAR levels, suggesting the presence of subclinical vascular and inflammatory alterations. Assessment of aortic elasticity and CAR may provide a simple and practical approach for early cardiovascular risk stratification in symptomatic pregnancy, particularly in ED settings. Further multicenter studies with longitudinal follow-up are warranted to clarify their prognostic significance. Full article

Green infrastructure (GI) provides essential ecosystem services for urban sustainability in the face of urbanization and climate change, including stormwater management, heat mitigation, and reduction in carbon dioxide (CO₂) concentration levels. Existing studies often focus on single-dimensional ecological effects, lacking a systematic investigation of their synergies and trade-offs. This study developed a coupled framework integrating scenario design, model simulation, and multi-indicator evaluation. Fifty-six scenarios, varying by GI combinations, weather conditions, and total annual runoff control rate (RCR), were applied to a high-density industrial district in Nanjing. The results showed that: (1) GI combinations enhanced comprehensive benefits, with the combination including bioretention (BR), permeable pavement (PP), and green roof (GR) performing most effectively. This was followed by the combination of BR and PP, then by BR and GR, while the use of BR alone provided the lowest effectiveness. (2) PP was a key synergistic component, improving heat mitigation and reducing CO₂ concentration levels through the beneficial effects of rainfall events. (3) Exceeding the optimal RCR threshold for some GI combinations diminished tree space and three-dimensional green volume, shifting synergies into trade-offs. (4) Three-dimensional green volume was positively correlated with reductions in Physiological Equivalent Temperature (PET) and CO₂ concentration, confirming its core role. (5) Rainfall boosted carbon sinks, while a significant cooling enhancement required PP. This study elucidates the water–heat–carbon synergy in small-scale GI, supporting multi-objective optimization in high-density urban renewal. Full article

The replacement of fishmeal with plant protein is widely regarded as a key strategy for sustainable aquaculture. However, carnivorous marine fish often show limited tolerance to fishmeal-free diets. Here, we investigated growth performance, hepatic physiological responses, and molecular mechanisms underlying adaptation to a soy protein concentrate-based diet (SPCD) in golden pompano (Trachinotus ovatus). An 8-week feeding trial was conducted under communal rearing conditions, followed by the phenotypic stratification of SPCD-fed fish into high- and low-growth subgroups. Growth performance, serum biochemical indices, and liver histology were assessed, and integrated transcriptomic and metabolomic analyses were performed on liver tissue. At the population level, the SPCD resulted in reduced growth, a lower feed intake, and decreased feed utilization efficiency compared with a fishmeal-based diet. Notably, marked inter-individual variation was observed: fish fed the SPCD exhibited significantly lower final body weights and a higher FCR compared with the FMD group (p < 0.001), and pronounced growth divergence was observed between the PB and PS subgroups, with a subset of SPCD-fed fish maintaining growth comparable to fishmeal-fed controls, whereas others exhibited severely constrained growth. Divergent phenotypes were associated with distinct hepatic alterations, including aggravated vacuolation, the enrichment of tight junction-related and immune regulatory pathways, and the broad reprogramming of lipid metabolism. Integrated multi-omics analysis identified arachidonic acid metabolism as the most significantly perturbed pathway, characterized by altered membrane phospholipid composition, the upregulation of RARRES3L, increased COX/LOX-derived eicosanoids, and the suppression of the CYP–EET branch. Collectively, these findings indicate that soy protein replacement induces coordinated hepatic structural and metabolic remodeling, with tight junction disruption and arachidonic acid metabolic reprogramming contributing to inflammatory imbalance and divergent growth phenotypes in T. ovatus. Full article

Background/Objectives: Osseointegration is essential for the long-term success of dental implants, and radiographic assessment may support the evaluation of peri-implant bone healing. This retrospective study evaluated peri-implant radiographic bone density (PIBD) as a potential indicator of osseointegration in patients who underwent successful implant-prosthetic rehabilitation. Methods: Patients with at least one endosseous dental implant and a minimum of two standardized periapical radiographs—one at placement (T0) and one during follow-up—were included. Digital radiographs were obtained using the paralleling technique and analyzed with ImageJ^®. Normalized bone density values were calculated for predefined areas of interest (AOIs). Marginal Bone Level (MBL) changes were also assessed. Statistical analyses included the Shapiro–Wilk test, Kruskal–Wallis test, and Dunn’s post hoc test with Bonferroni correction. Results: 88 implants in 64 patients were analyzed (198 radiographs; 1299 AOIs measurements). Normalized bone density showed significant temporal changes in several AOIs, mainly from 3 to 12 months, across coronal/middle/apical regions. PIBD decreased by approximately 8% between T0 and 3 months, followed by a significant increase at one year. MBL values were minimal and well below physiologic thresholds throughout follow-up. No significant correlation was found between MBL and normalized bone density. Conclusions: PIBD assessment may be a reliable, non-invasive tool for monitoring osseointegration during follow-up and supporting clinical decision-making in postoperative controls. The temporal pattern observed confirms three radiographic healing phases after implant placement: an initial decrease in PIBD during early remodeling, a subsequent increase reflecting osseointegration, and a final stabilization phase corresponding to tertiary implant stability. Full article

Clusterin is a chaperon protein that is involved in many physiological processes, including binding to beta-amyloid (Aβ). Recently, we showed that in Alzheimer’s disease (AD) model mice and human postmortem brains, there are elevated levels of methionine-oxidized clusterin in the disease state versus controls. These observations prompted us to investigate the possibility that elevated methionine-oxidized levels of clusterin in human blood plasma correlate with clinical diagnosis of both mild cognitive impairment (MCI) and AD stages. To achieve this goal, we have used a combination of Elisa kits for determining the total level of clusterin and methionine-oxidized clusterin in human blood plasma, enabling the quantification of a methionine-oxidized clusterin to total clusterin ratio. This ratio was correlated with the diagnostics of three groups of patients (normal controls (NL), MCI, and AD; with n = 44 per group). Accordingly, it was determined that there was a significant increase in the relative methionine-oxidized clusterin level in the MCI and AD groups compared to the controls. In conclusion, it is suggested that increased levels of methionine-oxidized clusterin in human blood plasma may serve as a potential marker for MCI and AD diagnosis. Full article

Background: Acute high-intensity exercise induces transient inflammatory and oxidative stress responses, mediated by redox-sensitive signaling pathways and reflected by elevations in interleukin-6 (IL-6) and lipid peroxidation products. Modulation of these responses through hydration-based redox interventions remains insufficiently characterized at the biochemical level. Objective: This randomized controlled trial investigated whether regular consumption of redox (alkaline) water influences exercise-induced inflammatory and oxidative stress markers in physically active adults. Methods: Forty physically active adults were randomized into an experimental group (EG; n = 20) and consumed redox water subjected to molecular-level modification, yielding alkaline hydrogen-enriched water (pH 9.2–9.4), or a control group (CG; n = 20) that consumed standard water. After eight weeks of intervention, participants performed a standardized maximal aerobic exercise test. Plasma IL-6 and malondialdehyde (MDA) concentrations were measured at baseline and immediately post-exercise. Statistical analyses included two-way repeated measures ANOVA and ANCOVA. Results: A pronounced group × time interaction was observed for IL-6 (F(1,38) = 36.89, p < 0.001). The EG exhibited a significant post-exercise reduction in IL-6, whereas the CG demonstrated a robust increase. A significant group × time interaction was also detected for MDA (F(1,38) = 4.98, p = 0.029), reflecting stable lipid peroxidation levels in the EG and increased levels in the CG; however, baseline-adjusted analyses indicated that post-exercise MDA differences were largely attributable to initial variability. Hematological and coagulation parameters remained within physiological ranges in both groups. Conclusions: Redox water intake was associated with lower immediate post-exercise IL-6 compared with controls after baseline adjustment; however, pronounced baseline imbalance limits causal interpretation and warrants confirmation in larger trials with balanced inflammatory profiles. These findings highlight a potential biochemical mechanism linking hydration redox properties with inflammatory regulation during physical stress. Full article

The Xinjiang wheat variety ‘Xindong 22’ was used as experimental material. Two soil moisture treatments were established: control (CK, 70–75% field capacity), drought (X1, 60–65%). The photosynthetic characteristics and resistance physiological indexes of wheat leaves under different stress levels were analyzed, and RNA-Seq technology was used to conduct transcriptome sequencing and analysis were performed on wheat leaves. The results showed that under drought stress, superoxide dismutase (SOD) activity was significantly enhanced, while peroxidase (POD) activity decreased. Soluble sugar and proline contents also increased. These changes likely enhanced reactive oxygen species scavenging, thereby reducing the content of malondialdehyde in the leaves. Meanwhile, under the X1 treatment, stomatal conductance and transpiration rate of wheat leaves showed a slow decreasing trend, the intercellular CO₂ concentration decreased slightly, the decline in Fv/Fm was relatively small, and the value of the non-photochemical quenching coefficient gradually increased. Transcriptome analysis identified 1881 differentially expressed genes (DEGs). Notably, drought stress induced the up-regulation of key genes involved in the ABA signaling pathway (e.g., SnRK2 and ABF) and the MAPK cascade, suggesting their crucial roles in mediating drought responses in this wheat variety. In the jasmonic acid signaling pathway, MYC2 functions as a positive regulator by interacting with JAZ proteins. These findings demonstrate that Xinjiang wheat employs integrated physiological and molecular strategies to cope with drought stress. Full article