Differences of energy intake and energy expenditure of elite Taekwondo players receiving summer vs. winter intensive training

[Purpose]

This study aimed to evaluate the energy expenditure and energy intake as an experiment of energy balance of elite Taekwondo players receiving summer vs. winter intensive training.

[Methods]

The summer training group (STG, n = 15) and the winter training group (WTG, n = 18) wore an accelerometer for the measurement of energy expenditure and maintained a daily dietary record for measurement of energy intake, for seven consecutive days during summer or winter intensive training.

[Results]

The total energy expenditure (TEE) (834.1 kcal, p < .001), the total counts (1,867 counts, p = .038), and the energy expenditure during moderate (384.6 kcal, p < .001) and vigorous activity (351.8 kcal, p < .001) were significantly lower in the STG than in the WTG. On the other hand, the macronutrient intake showed that intake of energy (902.7 kcal, p < .001), carbohydrates (82.6g, p < .001), and protein (93.9g, p < .001) in the STG were significantly lower than those of the WTG. When comparing TEE and total energy intake, the STG consumed 902.7 kcal less as energy than the WTG, while the STG performed 834.1 kcal more as TEE than that of the WTG.

[Conclusion]

In conclusion, both of the summer and winter intensive training are not proper for energy balance condition. Therefore, to promote the optimal energy balance during the summer or winter intensive training period, a training and sports nutrition program based on the amount of energy expenditure and energy intake for Taekwondo players should be considered.     

Effects of two weeks' mandatory snack consumption on energy intake and energy balance

Objective: Our goal was to compare the effects of mandatory consumption of commercial snack products (CSPs) on energy intakes and energy balance in free‐living adults and to assess the interaction between habitual level of CSP consumption and the interventions. Research Methods and Procedures: Four groups of 18 subjects (lean and overweight, males and females) were studied using a crossover design. Subjects consumed one type of CSP (high‐carbohydrate, high‐fat, or mixed composition) at three manipulations of energy 0 MJ (control), 1.5 MJ (low‐energy), and 3.0 MJ (high‐energy) each day during three 14‐day interventions. The study design was parallel for type of CSP (macronutrient composition) and within‐subjects for energy level. Subjects self‐recorded food intakes between Days 8 and 14, and body weights were investigator‐recorded on Days 1, 8, and 15 of each intervention period. Daily energy expenditure was estimated by heart rate monitoring. Results: Daily energy intakes increased from 10.4 MJ (control) to 11.1 MJ (low‐energy) and 11.5 MJ (high‐energy) (p < 0.001), resulting in a trend (not significant) for body weight gain. Energy balance was more positive when subjects were not recording their food intakes than when they were (p < 0.001). There was a trend (not significant) for greater increases in energy intake with increasing fat content, and energy density, of the interventions. Frequent CSP consumers compensated more for the interventions than did infrequent CSP consumers (R² = 0.125, p = 0.003). Discussion: Subjects partially compensated for energy when supplemented with CSPs over 14‐day periods, although this was insufficient to prevent some increase in energy balance. The level of compensation correlated with habitual energy intake from CSPs.     

Timing of potential and metabolic brain energy

The temporal relationship between cerebral electro-physiological activities, higher brain functions and brain energy metabolism is reviewed. The duration of action potentials and transmission through glutamate and GABA are most often less than 5 ms. Subjects may perform complex psycho-physiological tasks within 50 to 200 ms, and perception of conscious experience requires 0.5 to 2 s. Activation of cerebral oxygen consumption starts after at least 100 ms and increases of local blood flow become maximal after about 1 s. Current imaging technologies are unable to detect rapid physiological brain functions. We introduce the concepts of potential and metabolic brain energy to distinguish trans-membrane gradients of ions or neurotransmitters and the capacity to generate energy from intra- or extra-cerebral substrates, respectively. Higher brain functions, such as memory retrieval, speaking, consciousness and self-consciousness are so fast that their execution depends primarily on fast neurotransmission (in the millisecond range) and action-potentials. In other words: brain functioning requires primarily maximal potential energy. Metabolic brain energy is necessary to restore and maintain the potential energy.     

Dynamic energy correlation analysis of E. coli aspartokinase III and alteration of allosteric regulation by manipulating energy transduction pathways

Conformational change associated with allosteric regulation in a protein is ultimately driven by energy transformation. However, little is known about the latter process. In this work, we combined steered molecular dynamics simulations and sequence conservation analysis to investigate the conformational changes and energy transformation in the allosteric enzyme aspartokinase III (AK III) from Escherichia coli. Correlation analysis of energy change at residue level indicated significant transformation between electrostatic energy and dihedral angle energy during the allosteric regulation. Key amino acid residues located in the corresponding energy transduction pathways were identified by dynamic energy correlation analysis. To verify their functions, residues with a high energy correlation in the pathways were altered and their effects on allosteric regulation of AKIII were determined. This study sheds new insights into energy transformation during allosteric regulation of AK III and proposes a strategy to identify key residues that are involved in intramolecular energy transduction and thus in driving the allosteric process.     

Effects of forest management on the carbon dioxide emissions of wood energy in integrated production of timber and energy biomass

The aim of this work was to study the sensitivity of carbon dioxide (CO₂) emissions from wood energy to different forest management regimes when aiming at an integrated production of timber and energy biomass. For this purpose, the production of timber and energy biomass in Norway spruce [Picea abies (L.) Karst] and Scots pine (Pinus sylvestris L.) stands was simulated using an ecosystem model (SIMA) on sites of varying fertility under different management regimes, including various thinning and fertilization treatments over a fixed simulation period of 80 years. The simulations included timber (sawlogs, pulp), energy biomass (small‐sized stem wood) and/or logging residues (top part of stem, branches and needles) from first thinning, and logging residues and stumps from final felling for energy production. In this context, a life cycle analysis/emission calculation tool was used to assess the CO₂ emissions per unit of energy (kg CO₂ MWh^?1) which was produced based on the use of wood energy. The energy balance (GJ ha^?1) of the supply chain was also calculated. The evaluation of CO₂ emissions and energy balance of the supply chain considered the whole forest bioenergy production chain, representing all operations needed to grow and harvest biomass and transport it to a power plant for energy production. Fertilization and high precommercial stand density clearly increased stem wood production (i.e. sawlogs, pulp and small‐sized stem wood), but also the amount of logging residues, stump wood and roots for energy use. Similarly, the lowest CO₂ emissions per unit of energy were obtained, regardless of tree species and site fertility, when applying extremely or very dense precommercial stand density, as well as fertilization three times during the rotation. For Norway spruce such management also provided a high energy balance (GJ ha^?1). On the other hand, the highest energy balance for Scots pine was obtained concurrently with extremely dense precommercial stands without fertilization on the medium‐fertility site, while on the low‐fertility site fertilization three times during the rotation was needed to attain this balance. Thus, clear differences existed between species and sites. In general, the forest bioenergy supply chain seemed to be effective; i.e. the fossil fuel energy consumption varied between 2.2% and 2.8% of the energy produced based on the forest biomass. To conclude, the primary energy use and CO₂ emissions related to the forest operations, including the production and application of fertilizer, were small in relation to the increased potential of energy biomass.     

增强的UV—B辐射对麦田生态系统能量累积和流动的影响

研究了大田栽培和自然光条件下 ,模拟 UV- B辐射 ( UV- B,2 80～ 31 5nm)增强对麦田生态系统能量累积和流动的影响。在 5.31 k J· m- 2 UV- B辐射下 ,春小麦群体不同生育期叶、茎、根、穗、粒生物量和总生物量显著降低 ,各部位热值没有显著变化 ,各部位能量累积和总能量累积显著降低。能量累积与生物量呈极显著正相关 ,而与热值没有显著的相关性 ,可能生物量比热值对能量累积的贡献更大。 UV- B辐射显著降低春小麦群体能量输出 ,可能导致麦田生态系统能量流动功能下降。     

Inclusion of solvation free energy with molecular mechanics energy: alanyl dipeptide as a test case.

A combined force field of molecular mechanics and solvation free energy is tested by carrying out energy minimization and molecular dynamics on several conformations of the alanyl dipeptide. Our results are qualitatively consistent with previous experimental and computational studies, in that the addition of solvation energy stabilizes the C5 conformation of the alanyl dipeptide relative to the C7.     

干旱能源植物的发掘与应用策略

随着人类社会的快速发展和对化石能源的不合理开采,化石能源整体可开采量锐减;另一方面,化石能源的大量使用造成日益凸显的环境污染问题,发展生物质能源对解决能源危机、促进社会可持续发展具有重要意义。囿于人口持续增长和粮食需求不断增加,发展能源植物的重要突破口在于大力开发不与粮食作物争地争水的干旱能源植物。因此,从能源植物概念及其意义入手,论述国内外干旱能源植物应用现状和在实际种植生产过程中存在的问题,综合分析适合作为干旱能源植物的新类型,进而提出干旱能源植物的应用策略。     

Estimation of metabolisable energy and net energy of rice straw and wheat straw for beef cattle by indirect calorimetry

Two experiments were conducted to estimate the metabolisable energy (ME) and net energy (NE) of rice straw and wheat straw for beef cattle. In each experiment, 16 Wandong bulls (Chinese indigenous yellow cattle) were assigned to 4 dietary treatments in a completely randomised design. Four dietary treatments included one corn silage-concentrate basal diet and three test diets in which the basal diet was partly substituted by rice straw (Exp. 1) or wheat straw (Exp. 2) at 100, 300 and 600 g/kg. Total collection of faeces and urine was conducted for 5 consecutive days after a 2-week adaption period, followed by a 4-d period where gas exchange measurements were measured by an open-circuit respiratory cage. Linear regression equations of rice straw- or wheat straw-associated ME and NE contribution in test diets against rice straw or wheat straw substitution amount were developed to predict the ME and NE values of rice straw and wheat straw. These regression equations resulted in ME and NE values (dry matter basis) of 6.76 and 3.42 MJ/kg for rice straw and 6.43 and 3.28 MJ/kg for wheat straw, respectively. The NE and ME requirement for maintenance of Wandong cattle fed a straw-based diet were 357 and 562 kJ·kg^?0.75·d^?1, respectively. The regression-derived ME and NE have lower standard errors and coefficients of variation than those estimated by any single substitution ratio. Our study found that the regression method based on multiple point substitution is more reliable than the substitution method for energy evaluation of feedstuffs for beef cattle.     

Efficiency of energy utilisation and voluntary feed intake in ruminants

Energy requirements of animals are most readily expressed in terms of net energy (NE), while the energy yield of feed is, at least initially, expressed in terms of metabolisable energy (ME). Energy evaluation systems 'translate' NE requirements into ME requirements (ME systems) or assign NE values to feeds (NE systems). Efficiency of ME utilisation is higher for maintenance than for production and the NE yield of a feed varies, therefore, with ME intake. In addition, energetic efficiency for maintenance and production is thought to be different for lactating and non-lactating animals and to be affected by diet quality. As a result, there are currently many national energy evaluation systems that are complex, differ in their approach and are, as a result, difficult to compare. As ruminants in most production systems are fed ad libitum, this is also the most appropriate intake level at which to estimate energetic efficiency. Analyses of older as well as more recent data suggest that ad libitum feeding (i) abolishes the effects of diet quality on energetic efficiency (almost) completely, (ii) abolishes the differences between lactating and non-lactating animals (almost) entirely and (iii) results in overall energetic efficiencies that are always close to 0.6. The paper argues that there is now sufficient information to develop an international energy evaluation system for ad libitum fed ruminants. Such a system should (i) unify ME and NE systems, (ii) avoid the systematic bias and large errors that can be associated with current systems (iii) be simpler than current systems and (iv) have as a starting point a constant efficiency of ME utilisation, with a value of around 0.6. The remarkably constant efficiency of ME utilisation in ad libitum fed ruminants could be the result of energetic efficiency as well as feed intake regulation being affected by the same variables or of a direct role of energetic efficiency in feed intake regulation. Models to predict intake on the basis of the latter hypothesis are already available for non-reproducing ruminants but remain to be developed for reproducing animals.     

辽宁省能源消费和碳排放与经济增长的关系

在广泛收集资料的基础上,对辽宁省的能源利用效率、能源消费强度与经济增长的关系进行探索,其目的为辽宁省的节能与CO2减排及经济的快速发展提供科学依据。结果表明:辽宁整体单位GDP能耗高出全国水平52%—70%,第二产业单位GDP能耗是第三产业的5.67—8.41倍,第一产业的7.2—9.0倍;辽宁能源利用率只有全国平均水平的60%左右,第二产业能源利用效率只有第一产业的11.89%,第三产业的12.60%;GDP年增长速率大于能源消费量年增长速率,能源投入增加促进了国民生产总值的提高,但是经济增长并不是完全依赖能源消费的增长;能源消费量与经济增长的关系,呈现出"N型"曲线特征,随着GDP的增加,能源消费量出现反复上升和下降过程,辽宁省能源消费和经济增长关系没有达到长期的均衡性,尚处于非平衡的发展阶段。     

江苏省能源农业发展的资源现状与发展潜力

在讨论江苏省农村生物质类型和资源总量的基础上,利用已有统计资料和数据,对江苏省能源农业发展的资源基础现状进行定量的估算,并通过对发展能源农业的种质和可利用土地、江苏省农业和畜牧业发展态势的分析研究,对江苏省能源农业的发展潜力进行了预测.研究表明,2006年江苏省农村生物质能总蕴藏量和可利用量折合标准煤分别达到14238.06万t和2311.54万t.到2010年和2015年,江苏省农村生物质能资源量折合标准煤将分别达到5390万t和6109万t.     

Mammalian sirtuins and energy metabolism

Sirtuins are highly conserved NAD+-dependent protein deacetylases and/or ADP-ribosyltransferases that can extend the lifespan of several lower model organisms including yeast, worms and flies. The seven mammalian sirtuins, SIRT1 to SIRT7, have emerged as key metabolic sensors that directly link environmental signals to mammalian metabolic homeostasis and stress response. Recent studies have shed light on the critical roles of sirtuins in mammalian energy metabolism in response to nutrient signals. This review focuses on the involvement of two nuclear sirtuins, SIRT1 and SIRT6, and three mitochondrial sirtuins, SIRT3, SIRT4, and SIRT5, in regulation of diverse metabolic processes.     

The animal feed and energy conservation properties of AVOTAN (avoparcin)

AVOTAN, avoparcin is a glycopeptide antibiotic manufactured by Cyanamid (UK) via the fermentation of a strain of Streptomyces candidus. The gross energy requirement of manufacturing avoparcin is calculated and compared with the gross energy savings of feed utilisation when used in animal feeding regimes for broiler chickens, pigs, beef cattle and dairy cows for milk production.

Avoparcin improves farm animal production in terms of liveweight gains and feed conversion efficiency. So, by conserving animal feed it conserves the energy which would have been expended to produce that animal feed. The energy savings thus calculated range from one to two orders of magnitude on an energy ratio basis and so are very significant. The widespread use of avoparcin in world agriculture is therefore very beneficial in an energy conservation context.     

Temperature affects the partitioning of absorbed light energy in freshwater phytoplankton

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