Search Results (1,970)

This study investigated the impact of post-activation performance enhancement (PAPE) on the parameters of the 3 min all-out test (3MT) in non-motorized tethered running, applying the concept of complex networks for integrative analysis. Ten recreational runners underwent anthropometric assessments, a one-repetition maximum test (1RM), a running ramp test, and 3MT trials under both PAPE and CONTROL conditions across five separate sessions. The conditioning activity consisted of two sets of six back squats at 60% 1RM. For each scenario, complex network graphs were constructed and analyzed using Degree, Eigenvector, PageRank, and Betweenness centrality metrics. In the PAPE condition, anthropometric parameters and parameters related to aerobic efficiency exhibited greater centrality, ranking among the top five nodes. Paired Student’s t-tests (p ≤ 0.05) revealed significant differences between conditions for end power (EP-W) (CONTROL: 407.83 ± 119.30 vs. PAPE: 539.33 ± 177.10 (effect size d = −0.84)) and end power relativized by body mass (rEP-W·kg⁻¹) (CONTROL: 5.38 ± 1.70 vs. PAPE: 6.91 ± 2.00 (effect size d = −0.76)), as well as for the absolute and relative values of peak output power, mean output power, peak force, and mean force. These findings suggest that PAPE alters the configuration of complex networks, increasing network density, and may enhance neuromuscular function and running economy. Moreover, PAPE appears to modulate both aerobic and anaerobic contributions to performance. These results highlight the importance of network-based approaches for advancing exercise science and providing individualized strategies for training and performance optimization. Full article

Beer is a drink that has been a staple in human history, evolving from its beginning in antiquity to the present day. Nowadays, large breweries and other companies have set up laboratories focused on finding and developing new yeast strains for the brewing sector to meet consumers’ demand for new beer styles. Monascus spp. are ascomycota that have been known for hundreds of years. They are widely popular in Asian cuisine, especially in fermented foods. Studies show that Monascus spp. produce numerous food dyes and substances that positively influence human health. In the presented work, Monascus ruber was tested as a potential microorganism for the beer industry. Experiments included fermentation trials with Monascus ruber in four regimes: in aerobic condition, anaerobic condition, anaerobic condition with pH kept above 4.5, and in anaerobic condition with pH set to 4.5. As a reference, commercial Saccharomyces cerevisiae and Saccharomyces pastorianus were used. Fermentation parameters were evaluated by measurements of ethanol and extract level. The final product was tested for its colour in order to evaluate if monascus-derived pigments were present in the beverage. Moreover, a qualitative analysis of lovastatin and citrinin was performed in order to check if those monascus metabolites were present. Finally, small-scale consumer tests were performed in order to check the organoleptic properties of the obtained beverage. Results show that Monascus ruber is able to ferment beer wort in a similar manner as Saccharomyces strains, reaching a slightly lower degree of attenuation. Nevertheless, a longer lag phase was observed in monascus trials, except for the trial with preset pH at 4.5. The most visible change in the product was a reddish colour that appeared in the sample in aerobic conditions. The qualitative analysis showed that lovastatin and citrinin were present in the tested samples. Consumer tests show that experimental beer has a different taste than Saccharomyces-fermented products. Although the presented results are preliminary, they could be a good starting point for further research on monascus-based beverages. Full article

The untreated discharge of dairy industry wastewater, characterized by high organic and nutrient loads, poses a severe eutrophication threat, leading to oxygen depletion and the disruption of aquatic ecosystems, which necessitates advanced treatment strategies. Anaerobic digestion (AD) represents an effective and sustainable alternative, converting organic matter into biogas while minimizing sludge production and contributing to Circular Economy strategies. This study investigated the effects of fat concentration and operational temperature on the anaerobic digestion of dairy effluents. Three types of effluents, skimmed, semi-skimmed, and whole substrates, were evaluated under mesophilic 35 °C and thermophilic 55 °C conditions to degrade substrates with different fat content. Low-fat effluents exhibited higher COD removal, shorter lag phases, and stable activity under mesophilic conditions, while high-fat substrates delayed start-up due to accumulation of fatty acids and brief methanogen inhibition. Thermophilic digestion accelerated hydrolysis and methane production but demonstrated increased sensitivity to lipid-induced inhibition. Kinetic modeling confirmed that the modified Gompertz model accurately described mesophilic digestion with rapid microbial adaptation, while the Cone model better captured thermophilic, hydrolysis-limited kinetics. The thermophilic operation significantly enhanced methane productivity, yielding 105–191 mL CH₄ g⁻¹VS compared to 54–70 mL CH₄ g⁻¹VS under mesophilic conditions by increasing apparent hydrolysis rates and reducing lag phases. However, the mesophilic process demonstrated superior operational stability and robustness during start-up with fat-rich effluents, which otherwise suffered delayed methane formation due to lipid hydrolysis and volatile fatty acid (VFA) inhibition. Overall, the synergistic interaction between temperature and fat concentration revealed a trade-off between methane productivity and process stability, with thermophilic digestion increasing methane yields up to 191 mL CH₄ g⁻¹ VS but reducing COD removal and robustness during start-up, whereas mesophilic operation ensured more stable performance despite lower methane yields. Full article

Background and Objectives: Lower-extremity injuries are common among female athletes; however, their multifactorial predictors remain insufficiently understood. Given the interplay between physiological and psychological readiness in athletic performance, identifying the factors that influence lower limb performance is crucial for effective injury prevention. This study aimed to evaluate the predictive effects of physiological (VO₂peak, anaerobic power, agility, and isokinetic strength) and psychological (resilience and self-efficacy) variables on functional performance related to risk of injury. Materials and Methods: This cross-sectional study included 60 athletes with a mean age of 24.5 ± 6.90 years and mean body mass index of 23.12 ± 3.6 kg/m² (range: 16–30 kg/m²). The testing protocol included anthropometric measurements, the Lower Extremity Functional Test (LEFT), Wingate anaerobic cycling test, assessments of aerobic capacity, isokinetic muscle strength, and jumping performance (Single-Leg Hop [SLH] and Standing Long Jump [SLJ] tests). Psychological assessments included the General Self-Efficacy Scale (GSES) and a resilience questionnaire. A hierarchical regression analysis was performed. Results: The participants trained 5 ± 2 days per week and had 42 ± 39 months of sports experience. The mean VO_2peak was 40.82 ± 5.8 mL·kg⁻¹·min⁻¹, relative anaerobic peak power was 7.53 ± 1.92 W/kg, and fatigue index was 60.63 ± 15.41%. The mean isokinetic knee extension and flexion torque were 184.55 ± 44.60 N·m and 95.08 ± 21.44 N·m, respectively, with a flexion-to-extension ratio of 53.5%. The mean LEFT completion time was 160 ± 22 s. The participants demonstrated moderate resilience (BRS = 21 ± 4) and good self-efficacy (GSES = 33 ± 7.5). Among the psychological variables, GSES exhibited a modest negative correlation with LEFT (r = −0.28, p = 0.02). No significant associations were found between LEFT and psychological resilience. Longer LEFT completion times were associated with lower VO_2peak, mean power, and jump distance (p < 0.01). In the final model (R² = 0.58, p = 0.02), SLH (β = −0.54), VO_2peak (β = −10.32), and GSES (β = −0.70) were the strongest independent predictors of LEFT performance. Conclusions: SLH distance, VO_2peak, and general self-efficacy are key predictors of functional performance on the LEFT among female athletes. These factors may serve as practical indicators for identifying athletes who could benefit from targeted injury prevention programs. Full article

Background/Objectives: Lactate, traditionally considered a byproduct of anaerobic metabolism, is increasingly recognized as a biomarker of tissue perfusion and systemic stress. While hyperlactatemia is frequent after pediatric cardiac surgery, evidence regarding its prognostic role remains controversial. This study aimed to evaluate whether serial lactate measurements predict mortality in children undergoing surgery for congenital heart disease in Southeast Mexico. Methods: We conducted a retrospective cohort study including children aged 0–210 weeks with confirmed congenital heart disease who underwent first-time cardiac surgery between January 2022 and December 2024. Serum lactate was measured intraoperatively, at intensive care unit (ICU) admission, and at 12 and 24 h postoperatively using a Gem^® Premier™ 3500 analyzer. Sociodemographic, clinical, and surgical data were recorded. Associations between lactate levels and mortality were analyzed with Cox regression, adjusting for RACHS-2 category and intraoperative complications. Predictive performance was assessed with ROC curves and Harrell’s C-index. Results: 103 patients were included (median age 49.2 weeks; 60% female). Lactate levels overlapped intraoperatively but significantly discriminated against survivors from non-survivors thereafter. ICU admission lactate ≥ 4.2 mmol/L predicted mortality with 100% sensitivity and 60% specificity (AUC = 0.84). Hazard ratios confirmed that lactate at ICU admission (HR 2.17, 95% CI 1.16–4.06; p = 0.015), 12 h (HR 6.37, 95% CI 1.02–39.6; p = 0.047), and 24 h (HR 1.81, 95% CI 1.07–3.09; p = 0.028) were significant predictors of mortality. The model showed excellent discrimination (Harrell’s C = 0.986), though optimism due to the limited number of deaths should be considered. Conclusions: Serial lactate monitoring, particularly upon ICU admission, provides strong prognostic information for in-hospital mortality in pediatric cardiac surgery patients. Incorporating early postoperative lactate into routine monitoring may allow timely therapeutic adjustments. Preoperative lactate assessment warrants further evaluation as a potential risk stratification tool. Full article

Volleyball physical performance relies on the interaction between mechanical power, metabolic efficiency, and ventilatory regulation during repeated high-intensity actions. This study examined mechanical and cardiopulmonary responses during three consecutive 15 s countermovement jump bouts in female volleyball players, using simultaneous cardiopulmonary exercise testing. Eighteen female athletes (18–28 years) completed the protocol with 60 s active recovery between efforts. Mechanical performance showed a progressive decline (p < 0.01), with jump height decreasing from 20.59 ± 3.04 cm to 19.30 ± 3.23 cm and power output from 15.80 ± 2.61 to 14.83 ± 2.25 W/kg (p = 0.001). Oxygen uptake (VO₂) increased from 16.40 ± 6.73 to 20.87 ± 6.08 mL/min/kg (p = 0.002), while respiratory exchange ratio (RER) rose above 1.0, suggesting a growing anaerobic contribution. VE/VO₂ and PetO₂ also increased significantly (p < 0.001), indicating ventilatory adjustment to metabolic stress. Despite these adaptations, recovery between efforts appeared incomplete, reflected by persistent ventilatory and metabolic activation. These findings suggest moderate oxidative efficiency and partial fatigue compensation under short recovery conditions. The testing model may serve as a practical approach to evaluate the interplay between mechanical and metabolic performance and to refine individualized conditioning strategies in volleyball players. Full article

Background: Aggregatibacter actinomycetemcomitans is a Gram-negative, facultative anaerobic, immobile oral bacterium responsible for the secretion of virulence factors, namely leukotoxin (LtxA), a large exotoxin of the RTX family that enables the bacterium to evade the immune system by destroying leukocytes, resulting in aggressive periodontitis (AP) leading to tooth loss. Methods: This study aimed to screen 106 molecules derived from Moroccan propolis in order to identify potential inhibitors of the active sites of LtxA based on molecular docking, ADMET property evaluation, and molecular dynamics (MD) simulation. Results: Epigallocatechin gallate (EGCg), used as a reference compound, showed binding energies of −6.9 kcal/mol, −6.1 kcal/mol, −6.5 kcal/mol, and −5.9 kcal/mol with the four active sites P1, P2, P3, and P4, respectively. By establishing conventional hydrogen bonds, pi-alkyl bonds, and non-covalent pi–pi bonds. Chrysin and luteolin showed favorable binding affinities with the four active sites, named as follows: P1–P4 (P1–chrysin = −7.5 kcal/mol; P2–chrysin = −7.9 kcal/mol; P3–chrysin = −8.1 kcal/mol; P4–chrysin = −6.9 kcal/mol; P1–luteolin = −7.3 kcal/mol; P2–luteolin = −7.6 kcal/mol; P3–luteolin = −8.1 kcal/mol; P4–luteolin = −7.3 kcal/mol). The binding affinity of these two propolis derivatives was stabilized by pi−sigma bonds, pi−alkyl bonds, conventional hydrogen bonds, pi-cation interactions, non-covalent pi–pi bonds, and carbon–hydrogen bonds. According to free energy calculations performed with Prime MM-GBSA, the complexes formed by chrysin demonstrated the most stable interactions due to Van der Waals and lipophilic forces. Luteolin formed significant interactions, but slightly weaker than those of chrysin. These results reveal the inhibitory potential of chrysin and luteolin with protein active sites. MD simulations corroborated the excellent stability of complexes formed by chrysin, as indicated by low RMSD values, suggesting favorable dynamic behavior. Conclusions: These results highlight the potential of chrysin as a versatile inhibitor capable of interacting with the four active sites. These findings are a strong foundation for further experimental confirmations. Full article

Tuna-processing facilities produce substantial amounts of concentrated organic residues and sludges containing high levels of proteins, lipids, and nitrogen, which are not easily handled by conventional waste treatment methods. In this work, the anaerobic digestion (AD) performance of tuna-processing by-products (TPB1–2) and associated wastewater sludges (TWS1–3) was investigated using a combination of biochemical methane potential (BMP) tests, theoretical methane yield calculations based on the Buswell–Boyle equation, semi-continuous mono-digestion experiments, and 16S rRNA gene-based microbial analyses. Among the evaluated materials, TWS2 produced the highest methane yield (554.6 N mL CH₄/g VS) and, when its annual production volume was taken into account, showed the greatest estimated energy recovery (approximately 1.88 × 10⁶ kWh per year). By contrast, TWS3 exhibited the lowest methane yield (239.8 N mL CH₄/g VS), which was attributed to the presence of lignocellulosic sawdust and its limited biodegradability. TWS1 showed a moderate level of performance, with an estimated biodegradability of 62.3%, which may have been influenced by the addition of ferric salts and polymeric coagulants during sludge conditioning. In the semi-continuous digestion experiments, reactors that were initiated under relatively high total ammonia nitrogen (TAN) concentrations achieved stable operation within a shorter period, with the acclimation phase reduced by approximately one hydraulic retention time. These trends were supported by the microbial community data, where an increase in Bacillota-associated families, such as Tissierellaceae and Streptococcaceae, was detected along with a clear shift in dominant methanogens from Methanothrix to the more ammonia-tolerant Methanosarcina. Taken together, it is suggested that, when ammonia levels are appropriately managed, mono-digestion of tuna-processing sludges can be operated at a moderate organic loading rate. The process stabilization and energy recovery in nitrogen-rich industrial wastes are closely linked to gradual microbial adaptation rather than immediate improvements in methane yield. Full article

Anaerobic digestion of straw is a crucial method for agricultural waste valorization, yet its efficiency is limited by complex factors. This study employed machine learning to predict methane yield and optimize process parameters in biochar-amended straw digestion. A comprehensive dataset integrating experimental and literature data (100 samples, 15 input variables) was constructed, incorporating operational conditions, straw characteristics, and biochar properties (e.g., dosage, particle size, specific surface area, and elemental composition). Prediction models were developed using Random Forest (RF), XGBoost, and Support Vector Machine (SVM). Results indicated that the RF model achieved the best predictive accuracy, with an R² of 0.81 and RMSE of 36.9, significantly surpassing other models. Feature importance analysis identified feeding load, biochar dosage, and biochar carbon content (C%) as the key governing factors, collectively accounting for 65.7% of the total contribution. The model-predicted optimal ranges for practical operation were 15–30 g for feeding load and 5–20 g/L for biochar dosage. This study provides data-driven validation of biochar’s enhancement mechanisms and demonstrates the utility of RF in predicting and optimizing anaerobic digestion performance, offering critical support for sustainable agricultural waste recycling and clean energy generation. Full article

The global floriculture industry generates massive organic residues that pose environmental risks but offer untapped bioenergy potential. This review evaluates the feasibility of valorizing flower waste through anaerobic digestion (AD) by synthesizing experimental data on substrate characterization, pretreatment efficacy, and reactor performance. Results indicate that biochemical methane potentials (BMP) vary significantly, ranging from 89 to 412 mL_CH4·g⁻¹_VS, depending on plant species and tissue composition. Major bottlenecks include high lignocellulosic recalcitrance (lignin content up to 0.28 g·g⁻¹_TS) and the presence of inhibitory phenolic compounds. Analysis reveals that while alkaline pretreatments effectively disrupt lignocellulosic structures, co-digestion strategies are essential to mitigate inhibition and balance nutrient ratios. However, current research is predominantly limited to laboratory-scale batch assays, leaving a critical knowledge gap regarding long-term process stability and inhibition dynamics in continuous systems. To transform this laboratory concept into a scalable technology, future efforts must focus on pilot-scale continuous reactor trials, standardized testing protocols, and comprehensive techno-economic and life cycle assessments. Full article

Cactus leaves from the Cactaceae family, particularly the Opuntia genus, have attracted increasing attention as natural coagulants for water treatment applications. In this work, Cactus-based extracts were investigated for drinking water treatment through the coagulation–flocculation process. Several extraction routes were examined, including Ca-J, Ca-H₂O, Ca-NaOH (0.05 M), Ca-NaCl (0.5 M), and Ca-HCl (0.05 M), and their performance was evaluated using jar test experiments. The removal efficiencies of total coliforms (TC), anaerobic sulfite-reducing bacteria (ASRB), total suspended solids (TSS), and turbidity were assessed, and the most effective extract was subsequently tested in a semi-industrial pilot-scale coagulation–flocculation–settling system. The physicochemical properties of the Cactus material were characterized using FTIR, SEM, XRD, and MALDI-TOF analyses. Results revealed bioactive components, including carbohydrates, proteins, tannins, flavonoids, and glucose, with functional groups (carboxyl, hydroxyl, carbonyl) responsible for coagulation. XRD and SEM analyses showed a semi-crystalline structure and a heterogeneous surface with fiber networks, while MALDI-TOF confirmed the presence of flavonoid and tannin compounds. These features collectively contribute to the effective removal of turbidity, suspended solids, and microbial contaminants. Among the tested extracts, Ca-NaOH (0.05 M) exhibited the highest removal efficiencies, achieving 100% removal of TC and ASRB, 94.15% removal of TSS, and 70.38% turbidity reduction under laboratory conditions. Pilot-scale application of this extract resulted in a turbidity reduction of 66.65%. Additional water quality parameters, including total alkalinity (TA), total dissolved solids (TDS), pH, and electrical conductivity (EC), were monitored to evaluate process performance. Overall, the results highlight the strong potential of Cactus leaves as an effective, cost-efficient, and environmentally friendly alternative to conventional chemical coagulants. However, further research is required to enhance their scalability and commercialization. Full article

This study addresses the lack of transparent methods for calculating the energy requirements of pulsed electric field (PEF) pretreatments in biogas research. Two detailed approaches are proposed and evaluated to quantify the energy consumed during the pretreatment of lignocellulosic harvest residues (corn, soybean, and sunflower) using a low-frequency electric field. The first approach is based on previously measured capacitor parameters, including resistance (R_s, R_p), inductance (L_s), capacitance (C_p), and loss factor (D), which were interpolated to 50 Hz from measurements performed over the frequency range of 100 Hz to 10 kHz. The second approach relies on direct measurements of the effective voltage and current waveforms across the capacitor, followed by calculation of the power factor (cos φ). Both methods enable reliable estimation of energy consumption and differ primarily in the type of input data required: Method 1 is based on capacitor characteristics determined before and after pretreatment, while Method 2 uses real-time treatment data. Despite these differences, the two approaches yielded highly consistent results, confirming their robustness and applicability. The calculated energy values were subsequently incorporated into a net energy balance by comparing the energy consumed during pretreatment with the methane energy output from anaerobic digestion. For all three investigated lignocellulosic substrates, PEF pretreatment resulted in a positive energy balance under the applied process conditions. Full article

In the context of micro-polluted water sources, the performance decline of filtration units is a major challenge for the operational management of water supply plants. Therefore, it is necessary to systematically analyze the mechanism underlying the decline in filter media activity and optimize the pre-filtration treatment. This study focuses on waterworks, aiming to enhance filtration performance through filter media modification and a combined coagulant-oxidant strategy. A key innovation of this work is the development of a macro-microscopic correlation evaluation system. The results showed that the modified filter media increased the turbidity removal rate by 10.48% compared to the unmodified media. Furthermore, the combined coagulation–pre-oxidation scheme increased the removal rates for turbidity and UV₂₅₄ by 3.24% and 19.03%, respectively, compared to the single-process scheme. Combined with filter media characterization results, the deactivation mechanism of filter media can be inferred. During the high-algae period, microorganisms on the filter media generate anaerobic Extracellular Polymeric Substances (EPS), which form a biofilm with bacteria and adhere to the filter media. The viscous matrix of these EPS then encapsulates inorganic substances, resulting in hard-to-remove clumps. These clumps clog pores and hinder the adsorption of subsequent pollutants, ultimately leading to continuous deterioration in filter media performance until failure. Full article

The urgent need for effective food waste management, coupled with the scarcity of carbon sources for sewage treatment, highlights the potential of producing carbon sources from food waste as a mutually beneficial solution. This study investigated the production of carbon sources through anaerobic fermentation using the liquid phase of food waste three-phase separation. Compared with previous studies using raw food waste or mixed substrates, the liquid phase derived from three-phase separation is richer in soluble organic matter and has been pre-heated (80 °C), which facilitates subsequent fermentation and offers easier integration into existing food waste treatment plants. A series of lab-scale batch fermentation experiments were carried out at different temperatures, including ambient, mesophilic, and thermophilic conditions, as well as varying initial pH levels (uncontrolled, neutral, and alkaline). The experimental results indicated that optimal production parameters involve a 4-day mesophilic fermentation at 35 °C with an initial alkaline pH, which increased the total VFAs yield by 252.5% to 40.26 g/L and raised the acetic acid fraction to 45.5% of total VFAs. Under these conditions, there was an observed increase in the relative abundance of acidogenic bacteria and a decrease in that of methanogen archaea. Furthermore, the denitrification performance of the produced carbon source was evaluated in short-term tests, and near-complete nitrate removal was achieved within approximately 2 h. These findings suggest the fermented liquid phase of food waste is a promising partial substitute for conventional external carbon sources. Full article

Background: Neuromuscular determinants such as maximal force, maximal velocity, and upper-body power are recognized as key contributors to competitive swimming performance. However, despite the relevance of these dry-land qualities, their relationships with the physiological mechanisms underpinning in-water performance, particularly aerobic and anaerobic capacities, remain insufficiently established. Purpose: This study aimed to investigate the relationships between upper-body load–velocity profile parameters (theoretical maximal force: F₀; theoretical maximal velocity: V₀; and maximal power: P_max), aerobic capacity expressed through critical velocity, and anaerobic capacity in trained swimmers. Methods: Thirty competitive male swimmers (age = 16.50 ± 0.31 years) completed an upper-body load–velocity profile test using the bench press exercise to determine F₀, V₀, and P_max. Swimming performances in the 100, 200, and 400 m freestyle events were used to calculate critical velocity and anaerobic capacity based on a linear distance–time model. Pearson correlation coefficients and linear regression analyses were conducted to examine the relationships between variables. Results: P_max (r = 0.493, p = 0.006) and V₀ (r = 0.697, p < 0.001) showed moderate to strong correlations with critical velocity, whereas F₀ showed no significant association (r = 0.152, p = 0.422). Conversely, anaerobic capacity was strongly correlated with F₀ (r = 0.842, p < 0.001) but not with V₀ (p = 0.119). Regression models indicated that F₀ explained 71% of the variance in anaerobic capacity, while V₀ explained 48% of the variance in critical velocity. Conclusion: The findings demonstrated distinct contributions of neuromuscular qualities: speed and power-oriented parameters are associated with critical velocity, whereas maximal strength strongly associated with anaerobic capacity. Monitoring the upper-body load–velocity profile appears to be a relevant tool for individualizing dry-land training according to the aerobic and anaerobic demands of swimmers. Full article