Effects of age on children's intake of large and self-selected food portions

Objective: Whether developmental periods exist in which children become particularly sensitive to environmental influences on eating is unclear. This research evaluated the effects of age on intake of large and self‐selected portions among children 2 to 9 years of age. Research Methods and Procedures: Seventy‐five non‐Hispanic white children 2 to 3, 5 to 6, and 8 to 9 years of age were seen at a dinner meal in reference, large, and self‐selected portion size conditions in which the size of an entrée was age‐appropriate, doubled, and determined by the child, respectively. Weighed food intake data were collected. Entrée bite size and bite frequency were assessed. Height and weight measurements were obtained. Results: The effect of age on children's intake of the large portion was not significant. Entrée consumption was 29% greater (p < 0.001) and meal energy intake was 13% greater (p < 0.01) in the large portion condition than in the reference condition. Increases in entrée consumption were attributable to increases in average bite size (p < 0.001). Neither child weight nor maternal weight predicted children's intake of large portions. Self‐selection resulted in decreased entrée (p < 0.05) and meal energy (p < 0.01) only among those children who ate more when served the large portion. Discussion: The results of this research confirm that serving large entrée portions promotes increased intake at meals among 2‐ to 9‐year‐old children. These findings suggest that any age‐related differences in children's response to large portions are likely to be smaller than previously suspected.     

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.     

Limits to sustained energy intake IX: a review of hypotheses

Several lines of evidence indicate that animals in the wild may be limited in their maximal rates of energy intake by their intrinsic physiology rather than food availability. Understanding the limits to sustained energy intake is important because this defines an envelope within which animals must trade-off competing activities. In the first part of this review, we consider the initial ideas that propelled this area and experimental evidence connected with them. An early conceptual advance in this field was the idea that energy intake could be centrally limited by aspects of the digestive process, or peripherally limited at the sites of energy utilisation. A model system that has been widely employed to explore these ideas is lactation in small rodents. Initial studies in the late 1980s indicated that energy intake might be centrally limited, but work by Hammond and colleagues in the 1990s suggested that it was more likely that the limits were imposed by capacity of the mammary glands, and other works tended to support this view. This consensus, however, was undermined by studies that showed milk production was higher in mice at low temperatures, suggesting that the capacity of the mammary gland is not a limiting factor. In the second part of the review we consider some additional hypotheses that might explain these conflicting data. These include the heat dissipation limits hypothesis, the seasonal investment hypothesis and the saturated neural control hypothesis. Current evidence with respect to these hypotheses is also reviewed. The limited evidence presently available does not unambiguously support any one of them. Limits to sustained energy intake VIII: Król et al. (2003) J Exp Biol 206:4283-4291.     

The effect of dry cow winter management system on feed intake, performance and estimated energy demand

This research compared three wood-chip out-wintering pad (OWP; an unsheltered OWP; a sheltered OWP (both with a concrete feed apron); and an unsheltered OWP with silage provided directly on top of the wood-chip bedding (self-feed OWP)) designs and cubicle housing with regard to dairy cow performance during the pre-partum period, and for 8 weeks post partum. Data were compared during 2 years. In Year 1, the unsheltered (space allowance = 12 m2 per cow) and sheltered (6 m2 per cow) OWPs were compared with cubicle housing (n = 49 cows per treatment). In Year 2, all three OWP designs (12 m2 per cow) were compared with cubicle housing (n = 24 cows per treatment, split into two replicates). Animals were dried off and assigned to treatment in the autumn, and remained there until calving in spring. Subsequently, they were managed at pasture during lactation. Outcome measures for analysis during the pre-partum period were feed intake, live weight, body condition score (BCS), heat production and heat loss, and post-partum were live weight, BCS, milk yield and milk composition. In Year 1, all cows had a similar live weight, but both pre-partum and at calving cows on the unsheltered OWP had a lower BCS than cows in cubicles (P < 0.05). However, in Year 2, there were no differences in either live weight or BCS. In Year 1, cows in the unsheltered OWP produced less heat than in cubicles (P < 0.05), but in Year 2, there was no treatment effect. In both years, cows in unsheltered OWPs lost more heat than cows in the sheltered OWP (P < 0.001). Treatment had no effect on milk composition either year. However, in Year 2, cows in the self-feed OWP had higher milk yields than the other treatments (P < 0.05). The lower BCS and heat production values in unsheltered treatments during Year 1 were probably because of higher rainfall and wind-speed values of that year. However, in both years, live weight in all treatments increased pre partum, and BCS did not decrease, indicating that unsheltered cows did not need to mobilise body reserves. Thus, OWPs could be a suitable pre-partum alternative to cubicle housing for dry dairy cows with regard to some aspects of dairy cow productive performance. However, further research should be carried out to investigate longer-term effects.     

The effect of dietary carbohydrate intake on the metabolic response to prolonged walking on consecutive days

Six healthy subjects walked 37 km per day for four consecutive days on two occasions one month apart; on one walk, subjects consumed a high carbohydrate (CHO) diet (85 +/- 1% CHO, Mean +/- SE) and on the other walk an isocaloric low CHO diet (2 +/- 0% CHO) was consumed. Subjects were fasted each day until after the completion of the walk. Blood samples were obtained at rest prior to exercise and after completion of each of three laps of 12.3 km. Exercise intensity corresponded to approximately 17% of VO2max. The first day of each walk demonstrated that the pattern of substrate mobilisation in response to this type of exercise is highly reproducible, there being no difference in any of the parameters measured between the two walks. Circulating glucose, lactate, insulin and triglyceride levels remained essentially unchanged; alanine fell progressively and glycerol, free fatty acid (FFA) and 3-hydroxybutyrate (BHB) rose progressively. After the first day there was a general tendency for the blood glucose concentration to decline as exercise progressed; by the end of the walk on Day 2, blood glucose was lower on the low CHO diet than on the high CHO diet. On Day 4 plasma insulin was higher (p less than 0.05) on the high CHO diet than on the low CHO diet and declined progressively on both diets. Blood lactate and alanine concentrations were generally higher at rest on the high CHO diet, but fell so that no differences existed by the end of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

基于生态系统净化与人为调控耦合作用的水环境承载力评估

针对目前水环境承载力相关研究中未突显生态系统净化作用和人为调控作用的问题,从生态系统污染净化功能和人为调控污染削减功能两个角度,提出基于生态系统净化-人为调控耦合作用的水环境承载力概念,并构建流域环境承载力评估模型。以滇池流域为例,计算了2015年滇池流域水环境承载力。研究结果表明:滇池流域2015年水环境承载力综合指数为1.16,处于超载状态;流域环境承载力分布呈现北高南低,北部限制因子化学需氧量,南部为总磷;调水工程调入水量出境携带污染物约为流域水环境承载力的16%,对流域水环境改善十分重要;人为调控污染削减能力在流域水环境承载力中所占比例已超过50%,成为不可忽视的一部分。     

The effect of lysine intake on energy partitioning and utilization in growing pigs

An experiment utilizing 12 castrated male pigs within a body weight range of 23 - 147 kg was conducted to ascertain whether the alteration of protein quality by varying the level of lysine intake is influencing total energy retention, heat production and therewith efficiency of energy utilization for growth. The animals were allotted to two treatments of a constant medium (11.5 g/d) or high lysine intake (13.5 g/d) level on the basis of an isonitrogenous diet at an energy intake level of 1.3 MJ ME/kg BW0.75. Representing a tool for determining body composition, at target body weights of 35, 55, 80, 115 and 145 kg measurements of deuterium dilution space were undertaken. Protein and lipid accretion were calculated by difference, assuming accretion to contain 23.8 and 39.0 kJ/g, respectively. The results show a significant effect (p < 0.05) between treatment groups for the values of energy retained in protein, thus ensuring the intended alteration by protein quality. Furthermore total energy retention, heat production (difference between ME intake and energy retention) and therewith energy utilization demonstrate independence from the composition of body weight (BW) gain. These observations confirm earlier results, but however, seem to be in contrast to the supposition of a constant efficiency for protein (kp) and fat (kf) accretion, respectively. This may be attributed to a variable kp, in fact to a smaller kp at minor values for protein accretion due to an increased whole body protein turnover. Lacking evidence from experimental data for advantages in using constant values for kp and kf to determine the accurate energy requirement for growth, a uniform value for the efficiency of total energy retention seems to be more adequate.     

低氧预处理对低氧／复氧心肌能量代谢的作用

目的：研究低氧预处理（HPC）对心肌的保护作用,方法：借助^31P－NMR图谱技术,在模拟Langendorff离体灌流大鼠心脏的正常生理条件下,跟踪心肌高能磷酸化合物含量的动态变化。结果：在30min低氧期,PCr、ATP相对含量及PCr/Pi值逐渐减小,但HPC组减小的速度比对照组慢;而在复氧期,HPC组能提高心肌高能磷酸化合物含量的恢复程度,特别是复氧初期,HPC组PCr 、ATP相对含量及PCr/Pi值立即有了恢复;在本实验中,HPC对pHi的改善不显著。结论：HPC能降低后续长时间低氧及复氧阶段的心肌能量代谢,对心肌的低氧／复氧损伤具有保护作用。     

The activation energy for insertion of transmembrane alpha-helices is dependent on membrane composition

The physical mechanisms that govern the folding and assembly of integral membrane proteins are poorly understood. It appears that certain properties of the lipid bilayer affect membrane protein folding in vitro, either by modulating helix insertion or packing. In order to begin to understand the origin of this effect, we investigate the effect of lipid forces on the insertion of a transmembrane alpha-helix using a water-soluble, alanine-based peptide, KKAAAIAAAAAIAAWAAIAAAKKKK-amide. This peptide binds to preformed 1,2-dioleoyl-l-alpha-phosphatidylcholine (DOPC) vesicles at neutral pH, but spontaneous transmembrane helix insertion directly from the aqueous phase only occurs at high pH when the Lys residues are de-protonated. These results suggest that the translocation of charge is a major determinant of the activation energy for insertion. Time-resolved measurements of the insertion process at high pH indicate biphasic kinetics with time constants of ca 30 and 430 seconds. The slower phase seems to correlate with formation of a predominantly transmembrane alpha-helical conformation, as determined from the transfer of the tryptophan residue to the hydrocarbon region of the membrane. Temperature-dependent measurements showed that insertion can proceed only above a certain threshold temperature and that the Arrhenius activation energy is of the order of 90 kJ mol(-1). The kinetics, threshold temperature and the activation energy change with the mole fraction of 1,2-dioleoyl-l-alpha-phosphatidylethanolamine (DOPE) introduced into the DOPC membrane. The activation energy increases with increasing DOPE content, which could reflect the fact that this lipid drives the bilayer towards a non-bilayer transition and increases the lateral pressure in the lipid chain region. This suggests that folding events involving the insertion of helical segments across the bilayer can be controlled by lipid forces.     

The effect of local change in habitat quality on populations of migratory species

1. Habitat deterioration is a major problem world-wide as a result of processes such as change in land use, introduced species, human disturbance and exploitation of food supplies. Many studies have shown that habitat change can have considerable effect on the numbers of individuals using a site. For migratory species, however, the consequences for the total population cannot be deduced from local studies.
2. For a migratory species, the change in total population size Δ N , as a consequence of habitat change in the wintering area, can be calculated from Δ N  =  LM γ d '/( b ' +  d '), where γ is the expected proportional change in the number of birds using a site as a result of the habitat change, L is the area affected, M is the density of individuals using the site prior to habitat change, b ' is the strength of the per capita density-dependent breeding output, and d ' is the strength of the per capita density-dependent winter mortality. Similarly the consequences of habitat change in the breeding area can be calculated from Δ N  =  LM γ b '/( b ' +  d ').
3. The same approach can be used for predicting the consequences of improvements in habitat quality.
4. A worked example is given to illustrate how this approach could be used to predict the consequences for the total population of changes in the food supply of oystercatchers within one estuary.
5. There is a need for more measures of γ, the expected proportional change in the number of birds using a site as a result of various forms of habitat deterioration, and the strengths of density dependence.     

Evaluation of maize productivity considering solar energy use limitation by environmental factors

Evaluation of maize productivity under different climatic conditions was made by determination of the amount of the incident solar radiation energy in the PAR range, which can be potentially used by plants for photosynthesis. An irradiance, which can be stored in primary photosynthesis, designated as photosynthetic energy, W _ph, was estimated taking into account the action spectra of photosynthesis. Limitation of the W _ph usage, owing to unfavorable environmental factors was considered. Quantitative evaluation of limitations by two such factors, air temperature and soil water potential, was made by means of the coefficients F(i), which were defined as the ratio between the photosynthetic rate at a given value of a particular environmental factor and that at the optimal value for this factor. The coefficients F(i), were determined from the dependencies of the photosynthesis rate on air temperature and soil water potential as obtained in chamber and field experiments. In general terms, the fraction of W _ph, which can be utilized under a given climatic condition, was named bioclimatic potential, W _pc. In our model, the effect of monodominancy, when strong action of one factor suppresses the influence of any other factor, was considered. In this case, the bioclimatic potential, designated W′_pc, was calculated by multiplying W _ph times the coefficient F, for the factor which was most limiting during the period of measurement. There was close correlation between values of bioclimatic potential for the period of vegetation, W′_pc,v, and total dry matter. W′_pc,v use efficiency in the maize crop was also evaluated for five variants of mineral nutrition. This revised version was published online in June 2006 with corrections to the Cover Date.     

The cyclin-dependent kinase PITSLRE/CDK11 is required for successful autophagy

(Macro)autophagy is a membrane-trafficking process that serves to sequester cellular constituents in organelles termed autophagosomes, which target their degradation in the lysosome. Autophagy operates at basal levels in all cells where it serves as a homeostatic mechanism to maintain cellular integrity. The levels and cargoes of autophagy can, however, change in response to a variety of stimuli, and perturbations in autophagy are known to be involved in the aetiology of various human diseases. Autophagy must therefore be tightly controlled. We report here that the Drosophila cyclin-dependent kinase PITSLRE is a modulator of autophagy. Loss of the human PITSLRE orthologue, CDK11, initially appears to induce autophagy, but at later time points CDK11 is critically required for autophagic flux and cargo digestion. Since PITSLRE/CDK11 regulates autophagy in both Drosophila and human cells, this kinase represents a novel phylogenetically conserved component of the autophagy machinery.     

The effect of some biotic and abiotic factors on the fertility of planktonic rotifer species

The influence of some biotic and abiotic factors on the fertility of some planktonic rotifers was studied. Trophic factors, such as community structure and the amount of nannoplankton food available was of considerable influence to rotifer fertility, especially among sedimentators, while abiotic factors had a much smaller influence.     

The effect of energy reserves and food availability on optimal immune defence

In order to avoid both starvation and disease, animals must allocate resources between energy reserves and immune defence. We investigate the optimal allocation. We find that animals with low reserves choose to allocate less to defence than animals with higher reserves because when reserves are low it is more important to increase reserves to reduce the risk of starvation in the future. In general, investment in immune defence increases monotonically with energy reserves. An exception is when the animal can reduce its probability of death from disease by reducing its foraging rate. In this case, allocation to immune defence can peak at intermediate reserves. When food changes over time, the optimal response depends on the frequency of changes. If the environment is relatively stable, animals forage most intensively when the food is scarce and invest more in immune defence when the food is abundant than when it is scarce. If the environment changes quickly, animals forage at low intensity when the food is scarce, but at high intensity when the food is abundant. As the rate of environmental change increases, immune defence becomes less dependent on food availability. We show that the strength of selection on reserve-dependent immune defence depends on how foraging intensity and immune defence determine the probability of death from disease.     

Comparative analysis of energy intake and physical activity according to household type and presence of metabolic syndrome in middle-aged men based on data from the 7th Korea national health and nutrition examination survey (KNHANES) (2016-2018)

[Purpose] This study analyzed data from the 7^th Korean National Health and Nutrition Examination Survey (2016‒2018) to compare the differences in energy intake and physical activity (PA) levels in middle-aged Korean men aged 40-59 years according to household type and the presence of metabolic syndrome (MetS).[Methods] Data from 2,266 young adults (aged >39 years and <60 years) were obtained from the KNHANES. We analyzed the differences in energy intake and PA levels according to household type and MetS. The presence or absence of MetS was determined by measuring waist circumference, blood pressure, fasting blood glucose, triglyceride, and HDL-C levels.[Results] Regarding total nutritional intake, no relationship with MetS was observed regardless of household type (interaction between MetS and household type: p = 0.875). No differences in total PA were observed between multiple- and single-person households (interaction between MetS and household type: p = 0.122). The relationship between MetS and MetS components according to nutritional intake showed that participants with a higher energy intake had a 27% lower prevalence of low high-density lipoprotein cholesterol (HDL-C) (p < 0.05) and a 36% higher prevalence of high blood pressure (p < 0.01). The relationship between MetS and MetS components according to the PA level showed significantly reduced prevalence of MetS by approximately 39%, 35%, and 43% (p < 0.01, 0.01, and 0.001) in subjects who were somewhat active, active, and very active, respectively, compared to inactivity.[Conclusion] Middle-aged men showed no difference in nutritional intake and PA between multiple- and single-person households. However, the risk of MetS was significantly higher in participants with approximately 1.5 times the energy intake compared to the group with the lowest energy intake. Moreover, higher levels of PA had a marked positive effect on the risk factors and prevalence of MetS. Therefore, we suggest that reducing the total energy intake and increasing total PA are important for preventing MetS in middle-aged men regardless of household type.     

2型糖尿病环境因素与DNA甲基化的研究进展

2 型糖尿病(Type 2 diabetes mellitus, T2DM)是由于遗传与环境因素共同作用而引起葡萄糖代谢紊乱的疾病。DNA甲基化修饰的研究发现环境因素可以通过影响DNA甲基化修饰, 显著地增加T2DM的患病风险。目前, T2DM环境相关基因的DNA甲基化修饰研究已在人及动物的不同组织中取得进展。此外, T2DM相关基因的甲基化研究主要集中在糖代谢、能量代谢、炎症等。文章系统地综述了目前T2DM致病环境因素与DNA甲基化研究进展。     

Tissue fatty acid deposition is influenced by an interaction of dietary oil source and energy intake level in rats

To investigate the net tissue fatty acid deposition in response to graded levels of energy restriction and modification of diet fatty acid composition, rats were randomly assigned into four dietary groups and fed for 10 weeks diets containing 40% as energy of either fish, safflower, or olive oil, or beef tallow, consumed ad libitum or energy restricted to 85% or 68% of ad libitum intake by reducing diet carbohydrate content. An additional eight rats were killed before the diet regimen, to provide baseline data from which fatty acid deposition rates were calculated. Body weight, and heart, liver and fat mass gains were decreased with energy restriction (P<0.001). Olive oil feeding resulted in higher body weight gain (P < 0.03) than tallow feeding, whereas fish oil feeding was associated with highest (P < 0.007) liver weight and lowest (P < 0.03) fat mass gains. Energy deficit-related differences in the deposition of stearic, linoleic, arachidonic, and docosahexaenoic acids in heart and palmitic and docosahexaenoic acids in liver were dependent on the dietary oil consumed (P < 0.03). Similarly, interactive effects of restricted food intake and dietary oil type were found in the gain of palmitic, stearic, oleic, and linoleic acids in adipose tissue (P < 0.01) when expressed in relation to the amount of each fatty acid consumed. These data suggest that energy intake level can influence the deposition pattern, as well as oxidation rate, of tissue fatty acids as a function of tissue type, fatty acid structure, and dietary fatty acid composition.