Search Results (52)

This study explored the production and activation of biochar from rice straw residue for dye adsorption applications. Rice straw, a widely available but underutilized biomass, was processed to isolate lignin and generate biochar through pyrolysis at 450 °C and 550 °C. Activation using chemical agents (e.g., KOH and NaOH) was performed to enhance surface area and porosity. Among the tested conditions, KOH activation at a char-to-agent ratio of 1:3 produced activated carbon at 800 °C with the highest BET surface area (835.2 m²/g), and high fixed carbon (44.4%) after HCl washing. Thermogravimetric analysis was used to investigate pyrolysis kinetics, with activation energies determined using the Kissinger, Flynn–Wall–Ozawa, and Kissinger–Akahira–Sunose models. The brown solid showed a higher activation energy (264 kJ/mol) compared to isolated lignin (194 kJ/mol), indicating that more energy is required for decomposition. The AC was evaluated for the adsorption of methylene blue (MB) and methyl orange (MO) from aqueous solutions. Both dyes followed the Langmuir isotherm model, indicating that monolayer adsorption occurred. The maximum adsorption capacities reached 222 mg/g for MB and 244 mg/g for MO at 303 K, with higher values at elevated temperatures. Adsorption followed a pseudo-second-order kinetic model and was governed by a physisorption mechanism, as supported by thermodynamic analysis (ΔH < 20 kJ/mol and E_a < 40 kJ/mol). These findings demonstrate that KOH-activated biochar from rice straw residue is a high-performance, low-cost adsorbent for dye removal, contributing to sustainable biomass utilization and wastewater treatment. Full article

Background/Objectives: Low energy availability (LEA) can cause impaired reproductive function, bone health issues, and suppressed immune function, and may result in decreased performance and overall health status. The purpose of this study was to investigate adaptions of body composition, blood status, resting metabolic rate, and endurance performance to gain more comprehensive insights into the symptoms of LEA and the adaptive effects in the athlete population (active women (n = 11) and men (n = 11)). Methods: Three treatments were defined as 45 (EA45, control), 30 (EA30), and 10 (EA10) kcal/kg FFM/day and randomly assigned. Pre- and post-intervention measurements were performed through blood sampling, bioelectrical impedance analysis, resting metabolic rate measurement, the oral glucose tolerance test (OGTT), and the incremental endurance test to exhaustion. Results: There was a significant reduction in body weight and fat mass in EA10 compared to EA45 (p ≤ 0.05). Blood serum levels were altered in triglyceride, uric acid, and creatinine concentrations in EA10 compared to EA45 (p ≤ 0.05). Furthermore, blood glucose was still accumulated after 120 min during OGTT in EA10 compared to EA45 (p ≤ 0.05). The respiratory exchange ratio was reduced during submaximal stages of the incremental treadmill test to exhaustion without influencing performance output after treatment EA10 (p ≤ 0.05). However, the resting metabolic rate did not change (p > 0.05). Conclusions: In conclusion, this short-term study indicates that energy restriction can lead to several metabolic-related adaptations, which suggests that the availability and regulation of glucose and fats are significantly influenced after only five days of LEA in physically active women and men. Future research should focus on longer exposures of LEA and sex-specific comparisons (including the menstrual cycle) on LEA symptoms. Full article

Low energy availability (LEA) is common among female student-athletes and contributes to reduced bone mineral density and hormonal dysfunction. However, limited research exists on student-athletes of color, making it difficult to generalize results across populations, particularly Historically Black Colleges and Universities (HBCUs) student-athletes. Objectives: This study examined the energy needs and LEA prevalence, with or without eating disorder (ED) risk, among HBCU female student-athletes. Methods: Twenty-seven female student-athletes (age = 19 ± 1 year; height = 166.9 ± 7.6 cm; weight = 68.8 ± 11.3 kg) completed baseline measures, including the Eating Disorder Inventory-3 (EDI-3), EDI-3 symptom checklist (EDI-SC), anthropometric measures, and resting metabolic rate (RMR). Participants maintained a dietary log to measure energy intake and wore a heart rate monitor to estimate exercise energy expenditures for 7 days. LEA was defined as <30 kcal/kg of fat-free mass (FFM)/day. Results: The mean energy availability (15.9 ± 10.1 kcal/kg FFM/day) indicated 92.6% of participants (n = 25) displayed LEA; of those, 60% (n = 15) had LEA with ED risk. ED risk was identified in 59.3% of student-athletes (n = 13; EDI-3: n = 2; SC: n = 3; Both: n = 11). Interestingly, of the two student-athletes without LEA, one was identified at risk for EDs using both the EDI-3 and SC. Conclusions: HBCU female student-athletes face high risks of LEA and EDs, with most showing signs of both. This underscores the need for culturally sensitive interventions to improve EA and support mental health in this underserved group. Clinicians should focus on nutrition education and early ED identification to enhance long-term health and athletic performance. Full article

Background: This study investigated the effects of decreased energy availability (EA) and carbohydrate availability (CA) on reproductive and metabolic hormones in male endurance-trained athletes. Methods: Thirteen athletes (age: 26.08 ± 4.3 years; weight: 70.9 ± 6.5 kg; height: 179.9 ± 4.2 cm) participated in two training weeks with varying training volumes (low [LV] and high [HV]). The participants logged their diet and exercise for seven days and provided blood samples to measure hormone levels (Testosterone [T], insulin, leptin, cortisol, and interleukin-6 [IL-6]). Results: Results showed that 46.2% (HV) and 38.5% (LV) of participants were at risk for low EA (≤25 kcal/kg FFM·d-1), while 53.8% (HV) and 69.2% (LV) had low CA (<6 g/kg). Strong positive correlations were found between leptin and body fat percentage (DXABFP) in both weeks (HV: r(11) = 0.88, p < 0.001; LV: r(11) = 0.93, p < 0.001). Moderate correlations were observed between T and DXABFP (r(11) = 0.56, p = 0.05) and negative correlations between leptin and fat intake (r(11) = −0.60, p = 0.03). Regression analyses indicated significant relationships between DXABFP and T (F(1,11) = 4.91, p = 0.049), leptin (HV: F(1,11) = 40.56, p < 0.001; LV: F(1,11) = 74.67, p < 0.001), and cortisol (F(1,11) = 6.69, p = 0.025). Conclusions: These findings suggest that monitoring body composition and macronutrients can be clinically useful for male athletes, especially those without access to blood testing. Ultimately, a greater understanding of health and performance outcomes for male athletes is needed. Full article

Background/Objectives: Energy availability (EA) is essential for maintaining physiological functions, significantly influencing athletes’ health and performance. Nutritional behaviors, however, vary across sports. This study aims to assess EA levels in athletes from different disciplines, focusing on the relationship between EA and body composition in endurance athletes compared to rugby players. Methods: This study involved 18 endurance athletes (15 men, 3 women) and 36 rugby players (all men). Data were gathered through interviews, questionnaires, and bioimpedance analysis. Energy intake (EI) was measured with a 24 h dietary recall, and exercise energy expenditure (EEE) was calculated using the IPAQ questionnaire. EA was calculated as EA = (EI − EEE)/fat-free mass (FFM), with results categorized into clinical, subclinical, and optimal ranges. Results: The endurance group had a lower average FFM (57.81 kg) compared to the rugby players (67.61 kg). EA was also significantly lower in endurance athletes (11.72 kcal/kg FFM) than in rugby players (35.44 kcal/kg FFM). Endurance athletes showed more restrictive nutritional behavior with lower EI and higher EEE, but both groups maintained body composition within normal ranges. Conclusions: Endurance athletes exhibit greater nutritional restrictions compared to rugby players, though their body composition remains healthy. Further research is required to investigate the long-term effects of low EA on performance, injury risk, and potential impairment when EA falls below the optimal threshold of 45 kcal/kg FFM/day. Full article

Climbing is an Olympic discipline in full development and multidisciplinary in nature, where the influences of body composition and nutritional status on performance have not yet been clarified despite the quest for a low weight in anti-gravity disciplines such as climbing. The present cross-sectional study aimed to conduct nutritional (3-day dietary diaries) and body composition (ISAK profile) assessments on sport climbing athletes by gender and climbing level during the months of February and March 2024. The t-test for independent samples and the Mann–Whitney U-test, as well as an ANOVA and the Kruskal–Wallis H-test, were used to compare the distributions of two or more groups, respectively, and Pearson’s and Spearman’s correlation coefficients were used to estimate the correlations between the different variables. The mean age of the 46 Spanish climbers (22 men and 24 women) was 30 years (SD: 9) with 7.66 years of experience (SD: 6.63). The mean somatotype of the athletes was classified as balanced mesomorph. Negative correlations were observed between fat mass variables and climbing level (p < 0.010), and positive correlations were observed with forearm circumference (p < 0.050). The mean energy availability (EA) was 33.01 kcal-kg FFM⁻¹d⁻¹ (SD: 9.02), with 55.6% of athletes having a suboptimal EA status and 35.6% having low energy availability (LEA). The carbohydrate and protein intakes were below the recommendations in 57.8% and 31.1% of athletes, respectively. There were deficient intakes of all micronutrients except phosphorus in males. These findings suggest that climbing athletes are at a high risk of developing low energy availability states and concomitant problems. Optimal nutritional monitoring may be advisable in this type of athlete to try to reduce the risk of LEA. Full article

Background and Objectives: A sustained mismatch between energy intake (EI) and exercise energy expenditure (EEE) can lead to Low Energy Availability (LEA), as well as health and performance impairments characteristic of Relative Energy Deficiency in Sport (RED-S). Research in females has identified specific LEA cut-points for the risks of developing physiological and performance disturbances. Cut-points in males have yet to be evaluated; therefore, this study examined the prevalence of LEA in highly trained male cross-country skiers. The key purpose of this study was to analyze EI, resting energy expenditure (REE), EEE, and energy availability (EA) in highly trained cross-country skiers during the preparation and competition periods. The secondary objective of our study was to evaluate the relative contribution of fats and carbohydrates to EI, REE, and EEE. Materials and Methods: EI was determined by an estimated 24 h diet recall method, REE was assessed by indirect calorimetry, and EEE was estimated from heart rate in 27 cross-country skiers. Results: EI amounted to 4050 ± 797 kcal/day on a typical training day (TD) and 5986 ± 924 kcal/day (p < 0.001) on a typical competition day (CD). REE on TDs (2111 ± 294 kcal/day or 30 ± 6 kcal/day/kg) was higher (p < 0.05) than on CDs (1891 ± 504 kcal/day or 27 ± 7 kcal/day/kg). The EA in the athletes was <15 kcal∙kg FFM^–1·d^–1 on TDs and <65 kcal∙kg FFM^–1·d^–1 on CDs. EI was not optimal, as indicated by low EA throughout TDs (June). This could be associated with insufficient EI along with a high amount of EEE (3690.7 ± 485.2 kcal/day). During the transition from TD to CD, an increase in the contribution of fats to EI and EEE was observed in cross-country skiers. Conclusion: The conception of LEA and REDs and their potential implication for performance is underestimated among coaches and athletes. The importance of appropriate dietary strategies is essential to ensure that enough calories are consumed to support efficient training. Full article

This study explored the impact of varying energy availability (EA) on the 24-h interstitial fluid glucose concentration (IGC) in five elite male Japanese triathletes at a training camp. Measurements of IGC, energy and macronutrient intake, and exercise energy expenditure (EEE) through metabolic equivalents (METs) from training logs were conducted. Three subjects were evaluated over two 4-day periods, and two subjects over one 4-day period. Findings revealed significant correlations of daily mean nocturnal IGC with daily EA (r = 0.553, p = 0.001) and energy intake (EI) (r = 0.595, p < 0.001). However, no significant correlation was found between mean daily nocturnal IGC and EEE (r = −0.278, p = 0.124). Daytime IGC was ≥110 mg/dL for >50% of the time in all subjects, except on 1 day in one subject, and never fell <70 mg/dL. Therefore, daily EA may influence nocturnal IGC in elite male triathletes, although high daytime IGC levels were maintained without hypoglycemia. Full article

Accurately predicting the feedback mechanisms between forest ecosystem carbon cycling and climate change is crucial for effective climate mitigation. Understanding soil organic carbon (SOC) responses to the combined impacts of plant biomass, litter, and nitrogen deposition, especially regarding temperature sensitivity, is essential but remains poorly understood. We conducted incubation experiments using buried black soil from a cool temperate deciduous broad-leaved forest in Japan, which has high C content and a highly stable molecular structure. The stepwise addition of glucose and a temperature increase from 15 to 35 °C accelerated SOC mineralization by 74.0 mg C kg⁻¹ with a positive priming effect (PE) during the 49-day incubation period, while the simultaneous addition of nitrogen had no significant effect on this phenomenon, with SOC mineralization measured at 75.5 mg C kg⁻¹. Conversely, glucose mineralization was significantly accelerated by 10%, from 241.0 to 261.3 mg C kg⁻¹, by stepwise nitrogen addition and temperature increase. Under the combined impacts, the Q₁₀ value of the soil increased significantly from 1.6 to 2.0 compared to that in the unmodified conditions, primarily due to the stepwise addition of glucose. We also found a strong positive correlation between activation energy (E_a) and Q₁₀. This result strongly supports the carbon quality–temperature (CQT) hypothesis. These results likely stem from interactions between SOC quality and carbon availability, suggesting that, in the future, climate change is likely to have a positive feedback effect, especially on buried black soils. Full article

The integration of sustainability standards and value engineering methods in public education projects is a significant concern, as it ensures the well-being and sustainability goals of students, lecturers, and employees. This study aims to enhance sustainability within public education campuses by utilizing value engineering processes that establish a balanced correlation between the available budget costs and the sustainability costs that affect educational objectives, strategies, and the overall sustainability of the environment. In order to evaluate the integration of value engineering and the sustainability rating system “LEED protocols” for schools, the study utilized HAP (Hourly Analysis Program) software to perform numerical analysis, with the objective of improving environmental efficiency and cost-effectiveness in school buildings from the perspective of both male and female students. By applying this approach to all engineering disciplines, systems, and materials involved in the project, the study achieved impressive results, including a reduction in energy usage by 53.67%, a cost reduction of 27.48% from the total project budget, and 13 points earned in credit C1 and credit C2 in the Energy and Atmosphere EA category in LEED 2009. These findings are of great importance for the planning and execution of construction projects, specifically in the context of educational infrastructure, and provide valuable insights into the construction and renovation of school buildings, which can be used to enhance the safety, functionality, and aesthetic appeal of these facilities. Full article

Active athletes frequently develop low energy (LEA) and protein availabilities (LPA) with consequent changes in the vital metabolic processes, especially resting metabolic rate (RMR) and substrate utilization. This study investigated the association of energy and protein intakes with RMR and substrate utilization in male and female athletes and those with LEA and LPA. Sixty athletes (35% female, 26.83 ± 7.12 y) were enrolled in this study. Anthropometric measurements and body composition analysis were reported to estimate fat-free mass (eFFM). Dietary intakes were recorded by two-day multiple-pass 24 h recall records and three-day food records and then analyzed by food processor software to calculate protein intake (PI) and energy intake (EI). Indirect calorimetry was used to measure RMR and percentages of substrate utilization. Activity–energy expenditure (AEE) was assessed by using an Actighrphy sensor for three days. Energy availability was calculated using the following formula (EA = EI − AEE/eFFM). The correlation of EI and PI with RMR and substrate utilization was tested with Pearson correlation. In the LEA group, both EI and PI correlated positively with RMR (r = 0.308, 0.355, respectively, p < 0.05). In addition, EI showed a positive correlation with the percentage of fat utilization. In the male and sufficient-PA groups, PI correlated positively with the RMR and negatively with the percentage of protein utilization. In conclusion, the percentage of LEA is markedly prevalent in our sample, with a higher prevalence among males. Athletes with LEA had lower fat utilization and lower RMR, while those with sufficient PA showed lower protein utilization with excessive PI. These findings may explain the metabolic responses in the cases of LEA and LPA. Full article

Low energy availability (LEA) has been associated with several physiological consequences, but its impact on sleep has not been sufficiently investigated, especially in the context of young athletes. This study examined the potential association between energy availability (EA) status and objective sleep quality in 42 male rugby players (mean age: 16.2 ± 0.8 years) during a 7-day follow-up with fixed sleep schedules in the midst of an intensive training phase. Participants’ energy intake was weighed and recorded. Exercise expenditure was estimated using accelerometry. Portable polysomnography devices captured sleep on the last night of the follow-up. Mean EA was 29.3 ± 9.14 kcal·kg FFM⁻¹·day⁻¹, with 47.6% of athletes presenting LEA, 35.7% Reduced Energy Availability (REA), and 16.7% Optimal Energy Availability (OEA). Lower sleep efficiency (SE) and N3 stage proportion, along with higher wake after sleep onset (WASO), were found in participants with LEA compared to those with OEA (p = 0.04, p = 0.03 and p = 0.005, respectively, with large effect sizes). Segmented regression models of the EA-sleep outcomes (SE, sleep onset latency [SOL]), WASO and N3) relationships displayed two separate linear regions and produced a best fit with a breakpoint between 21–33 kcal·kg FFM⁻¹·day⁻¹. Below these thresholds, sleep quality declines considerably. It is imperative for athletic administrators, nutritionists, and coaches to conscientiously consider the potential impact of LEA on young athletes’ sleep, especially during periods of heavy training. Full article

In a scenario characterised by mitigation concerns and calls for greater resilience in the energy sector, energy audits (EAs) emerge as an essential mean for enhancing end-use energy consumption awareness and efficiency. Such a tool allows us to assess the different energy carriers consumed in a productive sector, offering insight into existing energy efficiency improvement opportunities. This opens avenues for research to devise an econometrics-based methodology that encapsulate production sites and their environmental essentials. This paper contributes to the literature by exploiting the EAs received by the Italian National agency for New technologies, Energy, and Sustainable Economic Development (ENEA) in 2019 from the Italian plastics manufacturing sector, matched with Italian firm-based data extracted from the Analisi Informatizzata delle Aziende Italiane (Italian company information and business intelligence) (AIDA) database. In particular, we investigate how the implementation of energy efficiency measures (EEMs) is influenced by a set of contextual factors, as well as features relating to the companies and EEMs themselves. The empirical investigation focuses on the EAs submitted to ENEA in 2019, which was strategically chosen due to its unique data availability and adequacy for extensive analysis. The selection of 2019 is justified as it constitutes the second mandatory reporting period for energy audits, in contrast to the 2022 data, which are currently undergoing detailed refinement. In line with the literature, the adopted empirical approach involves the use of both the OLS and logistic regression models. Empirical results confirm the relevance of economic and financial factors in guiding the decisions surrounding the sector’s energy performance, alongside the analogous influence of the technical characteristics of the measures themselves and of the firms’ strategies. In particular, the OLS model with no fixed effects shows that a one-percent variation in investments is associated with an increase in savings performance equal to 0.63%. As for the OLS model, including fixed effects, the elasticity among the two variables concerned reaches 0.87%, while in the logistic regression, if the investment carried out by the production sites increases, the expected percentage change in the probability that the energy-saving performance is above its average is about 187.77%. Contextual factors that prove to be equally influential include the incentive mechanism considered and the traits of the geographical area in which the companies are located. Relevant policy implications derived from this analysis include the importance of reducing informational barriers about EEMs and increasing technical assistance, which can be crucial for identifying and implementing effective energy solutions. Full article

Longitudinal measurements of Relative Energy Deficiency in Sport (REDs) among adolescent male elite athletes are lacking. We aimed to monitor REDs indicators and their possible impact on performance in elite high-school cross-country skiing and biathlon athletes (n = 13) (16.3 ± 0.4 years, 179.4 ± 7.6 cm, 63.6 ± 8.2 kg body mass (BM), and peak oxygen uptake (VO_2peak): 61.5 ± 5.3 mL/kg BM/min) every 6 months for 3 years. Protocols included assessments of energy availability (EA), body composition and bone mineral density (BMD), resting metabolic rate (RMR), disordered eating behavior, exercise addiction, VO_2peak, and muscle strength. Data were analyzed using a linear mixed model. At baseline, 38% had low lumbar BMD (Z-score ≤ −1), and overall, bone health increased only slightly. VO_2peak and muscle strength improved (p < 0.001), RMR decreased (p = 0.016), and no change was observed in EA or physiological or psychological REDs indicators. Conclusively, many of these young male athletes had poor bone health at baseline, and most either lost or did not achieve the expected pubertal bone mineral accrual, although no other indication of REDs was observed, while performance improved during the study period. Our findings highlight the importance of elite sports high schools focusing on screening for early detection of impaired bone health in male athletes. Full article

Previous studies demonstrate that “under-fuelling” (i.e., reduced carbohydrate (CHO) and energy intake (EI) in relation to recommended guidelines) is prevalent within adult female soccer players, the consequence of which may have acute performance and chronic health implications. However, the dietary practices of adolescent female soccer players, a population who may be particularly at risk for the negative aspects of low energy availability (LEA), are not well documented. Accordingly, we aimed to quantify EI and CHO intake, physical loading and estimated energy availability (EA) in elite national team adolescent female soccer players (n = twenty-three; age, 17.9 ± 0.5 years) during a 10-day training and game schedule comprising two match days on day six (MDa) and nine (MDb). The players self-reported their EI via the remote food photography method, whilst the physical loading and associated exercise energy expenditure were assessed via GPS technology. The relative CHO intake was significantly greater (all p < 0.05) on the day before the first match (MD-1a) (4.1 ± 0.8 g·kg⁻¹), on the day before the second match (MD-1b) (4.3 ± 1.1 g·kg⁻¹), MDa (4.8 ± 1.2 g·kg⁻¹) and MDb (4.8 ± 1.4 g·kg⁻¹) in comparison to most other days (<4 g·kg⁻¹). The mean daily measured EA over the 10-day period was 34 ± 12 kcal·kg FFM⁻¹·day⁻¹ (with six players, i.e., 34%, presenting LEA), though, when adjusting the energy intake for potential under-reporting, these values changed substantially (44 ± 14 kcal·kg FFM⁻¹·day⁻¹, only one player was classed as presenting LEA). Such data suggest that the prevalence of LEA amongst female team sport athletes may be over-estimated. Nonetheless, players are still likely under-fuelling for the work required in relation to the daily CHO recommendations (i.e., >6 g·kg⁻¹) for intensive training and game schedules. These data provide further evidence for the requirement to create and deliver targeted player and stakeholder education and behaviour change interventions (especially for younger athletes) that aim to promote increased daily CHO intake in female soccer players. Full article