State Of Energy Balance Research Articles

Improved energy balance calculation of unitary air conditioners via virtual in-situ calibration

Data-driven technologies for intelligent building energy management and automation have been developed under the energy balance state of systems. The datasets required are typically derived using energy and mass balance principles at each system boundary. Hence, the energy balance of systems significantly affects the system and building performances. However, sensor errors in a building energy sensor network can hinder the identification of balance states, thereby causing energy balance calculation errors in operational systems. In this study, the cooling capacity balance errors between the air and refrigerant sides of two unitary air-conditioner systems, caused by measurement errors, are investigated experimentally. Virtual in-situ sensor calibration (VIC) is performed to determine hidden sensor errors that cause the cooling capacity balance error, as well as to improve the balance and the degraded system performance analysis by calibrating the measurement errors. Experiments reveal the extent of cooling capacity balance errors occurring between the air and refrigerant sides under different operational conditions (0.5%–14.8%). VIC reveals erroneous measurements and the manner by which energy balance errors with measurement errors are solved (below 2%). Finally, the system performance analysis of the two test units shows that the VIC-driven calibration datasets improve the accuracy (0.3%–1.8% errors) of the system energy efficiency ratio even for new test cases after VIC is applied. The primary contributions of this study are as follows: (1) VIC is applied to solve energy balance calculation errors; (2) a strategy is proposed to overcome insufficient datasets to ensure energy balance improvements; and (3) calibrated measurements in real systems are validated.

Three-dimensional numerical manifold formulation with continuous nodal gradients for dynamics of elasto-plastic porous media

A three-dimensional (3D) numerical manifold formulation with continuous nodal gradients (H8-CNS) is presented for dynamic analysis of saturated elasto-plastic porous media based on the three-variable (u−w−p) formulation. Using meshes of 8-node hexahedra as mathematical patches, the skeleton displacement (u) and fluid velocity (w) interpolations are constructed with a constrained and ortho-normalized least-squares (CO-LS) scheme and a piecewise constant interpolation for fluid pressure field is employed. One feature of H8-CNS is to overcome locking in both limiting cases of low permeability and rigid skeleton. Another feature of H8-CNS is to achieve higher accuracy in stress results for porous media problems involving both elastic and elasto-plastic skeleton behaviors. H8-CNS is also able to fully capture dynamic responses of porous media under high-frequency loading. The accuracy and stability of H8-CNS are verified by performing a variety of numerical simulations. Time integration of H8-CNS is shown to be stable and accurate using the energy balance condition.

Effects of feeding rumen-protected linseed fat to postpartum dairy cows on plasma n-3 polyunsaturated fatty acid concentrations and metabolic and reproductive parameters

High-yielding dairy cows experience a negative energy balance and inflammatory status during the transition period. Fat supplementation increases diet energy density, and plasma n-3 polyunsaturated fatty acids (PUFA) have been proposed to improve immune function. This study tested the hypothesis that dietary supplementation with a rumen-protected and n-3 PUFA-enriched fat could ameliorate both the energetic deficit and immune status of postpartum high-yielding dairy cows, improving overall health and reproductive efficiency. At 11 d in milk (DIM), cows were randomly allocated to groups (1) n-3 PUFA (n = 29), supplemented with encapsulated linseed oil supplying additional up to 64 g/d (mean 25 ± 4 g/d) of α-linolenic acid (ALA), or (2) control (n = 31), supplemented with hydrogenated palm oil without ALA content. Fat supplements of the n-3 PUFA and control groups were available through an automated, off-parlor feeding system, and intake depended on the cow's feeding behavior. Plasma ALA concentrations were higher in n-3 PUFA than control cows, following a linear relation with supplement ingestion, resulting in a lower n-6/n-3 ratio in plasma. Metabolic parameters (body condition score and glucose and β-hydroxybutyric acid blood concentrations) were unaffected, but milk yield improved with increased intake of fat supplements. Plasma total adiponectin concentrations were negatively correlated with ingestion of n-3 PUFA-enriched fat supplement, following a linear relation with intake. Conception rate to first AI increased with higher intake of both fats, but a decrease of calving-to-conception interval occurred only in n-3 PUFA cows. Postpartum ovarian activity and endometrial inflammatory status at 45 DIM were unaffected. In conclusion, this study evinced a positive linear relation between rumen-protected linseed fat intake and plasma n-3 PUFA concentrations, which modulated adiponectin expression and improved reproductive parameters.

An autonomous depth-adjustment deployment algorithm by growth ring for underwater wireless sensor networks

In order to improve the coverage and reliability of UWSN under the condition of energy balance, an autonomous depth-adjustment deployment algorithm for sensor nodes of UWSN based on growing ring is proposed in this paper. A growth ring style-based scheme is adopted to construct the connective tree structure of sensor nodes. As for the depth-adjustment of nodes, a global optimal depth-adjustment algorithm with the goal of comprehensive optimization of both maximizing coverage utilization and energy balance is proposed. The experiments show that the proposed algorithm improves the reliability of UWSN under the condition of energy balance. Moreover, the algorithm in this paper improves the network coverage greatly while guaranteeing full connectivity.

Reduced adaptive thermogenesis during acute protein-imbalanced overfeeding is a metabolic hallmark of the human thrifty phenotype

The human thrifty phenotype is characterized by a greater decrease in 24-h energy expenditure (24EE) during fasting due to relatively higher eucaloric 24EE in sedentary conditions, both of which are indicative of greater propensity to weight gain. Thriftiness is also associated with a smaller increase in 24EE (i.e., reduced adaptive thermogenesis) during overfeeding. We investigated whether short-term measures of adaptive thermogenesis during overfeeding with low/normal/high protein content characterize thriftiness. In this secondary cross-sectional analysis of a single-arm crossover study, 24EE was measured using whole-room indirect calorimetry during energy balance, fasting, and different overfeeding conditions (low/3% protein, high/30% protein, and 3 normal/20% protein diets) with 200% of eucaloric requirements in 77 healthy individuals [63 men; BMI (in kg/m2): 26.4±4.3; body fat by DXA: 27.7%±9.4%, mean±SD] with normal glucose regulation. Relations between the 24EE during energy balance (adjusted for body composition) and 24EE during each overfeeding diet were analyzed using separate linear regression models. Participants were arbitrarily categorized as thrifty/spendthrift based on the median value (-177kcal/d) of the difference in 24EE between fasting and energy balance conditions. Differences in 24EE during low/high-protein overfeeding diets (regression line slope=0.76 and 0.68, respectively, both P<0.05 compared with slope=1) but not during the normal-protein overfeeding diets (all P>0.05 compared with slope=1) were dependent on baseline 24EE during energy balance. Specifically, individuals with higher eucaloric 24EE (thriftier phenotype) showed smaller increases in 24EE during protein-imbalanced overfeeding. Analyzed by group, thrifty individuals had smaller increases in 24EE by 42 and 237kcal/d during low- and high-protein overfeeding, respectively, compared with spendthrift individuals who showed greater increases in 24EE by 100 and 302kcal/d (P≤0.03 compared with thrifty group). During acute overfeeding conditions with low/high-protein content, thrifty participants have limited capacity to increase 24EE, indicating that impaired adaptive thermogenesis during protein-imbalanced diets further characterizes the thrifty phenotype and its susceptibility to weight gain. This trial was registered at clinicalTrials.gov as NCT00523627.

Functional Mixture-Based Positional Scan Identifies a Library of Antagonist Tetrapeptide Sequences (LAtTeS) with Nanomolar Potency for the Melanocortin-4 Receptor and Equipotent with the Endogenous AGRP(86-132) Antagonist.

The melanocortin-4 receptor (MC4R) plays an important role in appetite. Agonist ligands that stimulate the MC4R decrease appetite, while antagonist compounds increase food consumption. Herein, a functional mixture-based positional scan identified novel MC4R antagonist sequences. Mixtures comprising a library of 12,960,000 tetrapeptides were screened in the presence and absence of the NDP-MSH agonist. These results led to the synthesis of 48 individual tetrapeptides, of which 40 were screened for functional activity at the melanocortin receptors. Thirteen compounds were found to possess nanomolar antagonist potency at the MC4R, with the general tetrapeptide sequence Ac-Aromatic-Basic-Aromatic-Basic-NH2. The most notable results include the identification of tetrapeptide 48 [COR1-25, Ac-DPhe(pI)-Arg-Nal(2')-Arg-NH2], an equipotent MC4R antagonist to agouti-related protein [AGRP(86-132)], more potent than miniAGRP(87-120), and possessing 15-fold selectivity for the MC4R versus the MC3R. These tetrapeptides may serve as leads for novel appetite-inducing therapies to treat states of negative energy balance, such as cachexia and anorexia.

The importance of dietary balance at COVID-19: the systematic review

Introduction: COVID-19 disease has been heralded as a global pandemic by the World Health Organization. Dietary therapy and immunity play a decisive role in SARS-CoV-2 infection. In this sense, the lack of regulation and the excessive immune response to the viral stimulus produces an exacerbated pro-inflammatory cytokines (cytokine storm), reaching the state of hyperinflammation. Objective: To conduct a systematic review of the main considerations in the management of dietary therapy in the control or prophylaxis of COVID-19. Methods: Clinical studies with qualitative and/or quantitative analysis were included, following the rules of the systematic review-PRISMA. Results: A total of 370 articles were found involving dietary therapy, immunity, and COVID-19. A total of 107 articles were evaluated in full, and 28 were included and discussed in this study. Underlying systemic inflammation is believed to exacerbate COVID-19 infection. Studies have shown that there is a high risk of mortality in individuals with pre-existing health problems, such as diabetes, hypertension, cardiovascular disease, and obesity. Nutritional status is known to play a significant role in patient outcomes. It is necessary to follow a diet characterized by anti-inflammatory properties to benefit or prevent COVID-19. Adequate supplies of zinc, selenium, and vitamin D are essential for resistance to other viral infections, immune function, and reduced inflammation. There are nutritional triggers to favor immune-strengthening responses, as well as improving the performance of mitosis, meiosis, and all cellular functioning, all of this functioning is directly integrated with the energy balance and nutritional status of the body. Endogenous metabolites and nutrients in the diet can directly influence epigenetic enzymes. Conclusion: It is necessary to control the activities of inflammatory mediators through modifiable risk factors, such as diet, exercise, and healthy lifestyle choices to control or prevent the harmful effects of COVID-19.

Reducing hepatic endoplasmic reticulum stress ameliorates the impairment in insulin signaling induced by high levels of β-hydroxybutyrate in bovine hepatocytes

Ketotic dairy cows exhibit a state of negative energy balance (NEB) characterized by elevated circulating levels of β-hydroxybutyrate (BHB) and fatty acids. Impaired hepatic insulin signaling in dairy cows occurs frequently during the transition into lactation, but its role on liver function during this period is not well known. In nonruminants, endoplasmic reticulum (ER) stress is a causal factor contributing to impaired insulin signaling in the liver. Thus, the aim of this study was to investigate the status of hepatic insulin and ER stress signaling and whether ER stress contributes to impaired insulin signaling in dairy cows with ketosis. Healthy (control cows, n = 10, BHB ≤0.6 mM) and ketotic (ketotic cows, n = 10, BHB ≥1.2 mM) cows at 3 to 10 d in milk were selected for liver biopsy and blood sampling before feeding. In vitro experiments were conducted with isolated hepatocytes from 5 healthy calves (1 d old, fasted female, 30-40 kg of body weight). Treatments included BHB (0, 0.9, 1.8, 3.6 mM), tauroursodeoxycholic acid (TUDCA, a canonical inhibitor of ER stress), and different incubation times (0.5, 1, 2, 3, 5, 7, 9, or 12 h). Ketotic cows had lower daily milk yield (median: 29.50 vs. 23.00 kg), higher plasma nonesterified fatty acid (NEFA) (median: 0.33 vs. 1.17 mM), BHB (median: 0.43 vs. 3.22 mM), aspartate aminotransferase (median: 70.58 vs. 155.70 U/L), alanine aminotransferase (median: 18.31 vs. 37.90 U/L), lower plasma glucose (median: 4.32 vs. 2.37 mg/dL), and revised quantitative insulin sensitivity check index (median: 0.39 vs. 0.37) compared with healthy cows. Increased abundance of phosphorylated insulin receptor substrate-1 (IRS1) and decreased abundance of phosphorylated protein kinase B (AKT) and glycogen synthase kinase-3β (GSK3β) in ketotic cows indicated a state of insulin resistance. In addition, abundance of phosphorylated protein kinase RNA-like ER kinase (PERK) and inositol requiring protein-1α (IRE1α), and cleavage of activating transcription factor-6 (ATF6) were greater in the liver of ketotic cows. In vitro, at the early stages of incubation, treatment with BHB upregulated abundance of phosphorylated of IRE1α, PERK, and the cleavage of ATF6, as well as several unfolded protein response genes [X-box-binding protein-1 (XBP1), 78 kDa glucose-regulated protein (GRP78), and C/EBP homologous protein (CHOP)]. Furthermore, in response to increasing doses of BHB, the phosphorylation level of PERK, IRE1α, and the cleavage of ATF6, and the abundance of XBP1, GRP78, and CHOP increased. In addition, BHB treatment increased phosphorylation of IRS1 and decreased phosphorylation of AKT and GSK3β, and upregulated abundance of gluconeogenic genes (phosphoenolpyruvate carboxykinase and glucose-6-phosphatase). Importantly, these changes were reversed by inhibiting ER stress with TUDCA treatment. Overall, the present study indicated that reversing ER stress during ketosis might help alleviate hepatic insulin resistance. Targeting ER stress may represent a potential therapeutic target for controlling the negative aspects of ketosis on liver function.

Seasonal effect of milk yield and blood metabolites in relation to ketosis of dairy cows fed under a high ambient temperature.

Background and Aim:Metabolism and environment are closely related. Under high ambient temperature (HTa), dairy cows may have different energy metabolism during summer and winter. The present study was carried out to investigate the effect of HTa on the milk yield and blood concentration of beta-hydroxybutyrate (BHBA) and glucose at the herd level.Materials and Methods:One large dairy farm in Thailand with more than 100 crossbred Holstein cows milked each month was selected. The first experiment was performed on non-lactating cows to determine the normal daily concentrations of blood BHBA and glucose. Under the HTa condition, there was no significant change in blood BHBA and glucose concentrations. The second experiment was performed using a prospective cohort clinical design to demonstrate the seasonal effect on milk yield and blood BHBA as an indication of energy metabolism at the herd level.Results:The temperature and humidity index for the winter (78.1±0.5) and summer (83.4±0.7) periods differ significantly. The average milk yield during the winter period was 17.8% higher than during the summer period. The reduction of body condition score (BCS) during early lactation was significant in the winter cows. Both higher milk yield and lower BCS in the winter cows suggested a state of negative energy balance. However, there was no difference in blood BHBA and glucose concentrations between winter and summer cows. The effect of HTa on insulin signaling appeared to be a counterbalancing factor for the ketogenic status. Based on the present results, it would be interesting to further investigate the incidence of subclinical and clinical ketosis in a dairy farm under tropical conditions.Conclusion:The present experiment revealed that HTa during summer decreased milk yield in dairy cows fed under tropical conditions. Higher milk yield in winter caused a greater reduction of BCS and suggested a greater negative energy balance. However, there was no seasonal effect on blood BHBA and glucose concentrations.

Hipocalcemia e cetose - principais doenças metabólicas da vaca leiteira durante o período de transição - uma revisão de literatura

With the increased production demand in the dairy industry comes the need to keep animals healthier, thus avoiding large economic losses due to low productivity. During the transition period, dairy cows are susceptible to the onset of infectious diseases and metabolic imbalances due to the big change in their diet, it could be poor in needed nutrients to maintain the animal's body score, with this, the dry matter intake decreases up to 40% while energy expenditure increases due to milk and colostrum production, getting into a negative energy balance state.

The potential of biodiesel in mitigating the energy crisis in Sub-Saharan Africa energy sectors

As a result of the damaging effects they have on the climate, recent campaigns against fossil fuels, constantly emphasize the need to completely eliminate their use. To this effect, is a pressing need to source for other sources of energy that have the ability to decrease the level of greenhouse gas emissions to the atmosphere. These alternatives have to be easily accessible and should contribute to the industrial expansion of developing regions, especially Sub-saharan Africa. Poor access to electricity is a major challenge that contributes to the retarded state of development of some countries in Sub-saharan Africa, and renewable energy alternatives, such as biofuels, can perfectly solve this oddity. Biofuels possess unique attributes that can help the world attain a state of energy security and energy balance. The depletion of fossil fuels and other factors like technological advancement and current industrial expansion occurring in most countries in Sub-saharan Africa poses a threat to the availability of energy in the region and it is a major setback to the achievement of the United Nation's Sustainable Development Goal 7. Narrowing down to the use of biodiesels, implementing their use can save the continent from a lot of damage and build up a more sustainable energy sector. Massive deployment of Biodiesels into the energy sector of Sub-saharan Africa will not only ease the difficulty in accessing energy, it will also boost the agricultural sector and economy of the countries that constitute the region. This paper reviews the current state of biodiesel in the African sub-saharan region.

An improved air entrainment model for stepped spillways

This work considers the application of the air entrainment model developed in [P. Lopes et al. Int. J. Nonlin. Sci. Num., vol. 18, pp. 559-574, 2017] to simulation of flows in stepped spillways. Four Froude numbers are considered for the flow, with parameters selected to match available experimental data. An extensive simulation campaign led to the identification of several deficiencies in the model, most importantly, its strong grid dependence. An improvement to the interface detection algorithm used in the model is proposed, and simulations reveal improved robustness with respect to the grid density. Furthermore, two criteria for predicting the inception point of air entrainment are tested, based on energy balance and boundary layer state, respectively. The boundary layer-based approach is recommended due to superior accuracy and robustness with respect to turbulence model selection.

RELATIONSHIP BETWEEN RETAINED PLACENTA AND BODY CONDITION CHANGES DURING THE TRANSITION PERIOD IN HOLSTEIN DAIRY COWS IN NORTH-EASTERN ALGERIA

Retained placenta (RP) is a common complication of bovine parturition. It is a multifactorial reproductive disorder that predisposes to infection and hence, to infertility. The impact of body condition changes during the transition period on the risk of RP appearance was evaluated in 12 Holstein dairy cows calving from October to January in north-eastern Algeria. The animals were body condition scored (BCS) 3 weeks antepartum and two weeks postpartum to assess the peripartum body fat loss (BCS loss). The statistical analysis involving variables related to BCS and parity was performed using the principal component analysis (PCA). An RP critical occurrence of 41.66% exceeding significantly the threshold prevalence of 10% (p&lt;0.05) was recorded. This could be related to the BCS loss that exceeded one unit over the transition period (r=0.84, p&lt;0.01), expressing the high body fat mobilisation in response to stressor factors such as negative energy balance, feed availability and climatic condition. Scoring the body condition, particularly around the peripartum, may serve as a tool to monitor the risk factors related to the energetic status of dairy cows.

Snowpack thermal patterns in pre- and post-bushfire Snow Gum forests

Forests exert control on snowpack properties and processes through their modification of energy balance and micrometeorological conditions. Though forest disturbance by fire is increasing in frequency and severity in many warm regions containing seasonal snowpacks, increases are also expected in high latitude and altitude regions as a result of climate change. The influence of fire on snowpack internal thermodynamics, particularly at the snowpack – tree stem interface has yet to be examined. This study measured tree stem temperatures, horizontal snowpack temperatures surrounding tree stems, vertical internal snowpack temperatures, and micrometeorological variables to determine snowpack thermodynamics in undisturbed and fire-disturbed Eucalyptus pauciflora (Snow Gum) forests in the Australian Alps. Analysis focused on average snowpack temperature characteristics of each area and the micrometeorological drivers of internal snowpack temperatures. Shortwave radiation at the fire-disturbed forest was ~ 700% higher than that of the undisturbed forest, with stem temperatures exceeding ambient air temperature by an average of 5.3 °C. By comparison, average stem temperatures at the undisturbed forest were an average of 1.8 °C lower than ambient air temperatures. Increased stem temperatures were associated with tree wells of more uniform development in size, shape, and distribution within the fire-disturbed forest. Increased shortwave radiation and ambient air temperature at the fire-disturbed forest coincided with greater diurnal variation in snowpack temperature. In general, snowpack temperature was heavily dependent on location in the snowpack surrounding the stem and snowpack depth. Ambient air temperature was found to be the primary meteorological driver of horizontal snowpack temperature changes when examining variable importance from a Random Forest regression model. This study finds that changes in snowpack dynamics at the scale of individual tree stems is very important when considering fire impacts on hydrological processes in forested regions.

Stimulation of melanocortin-3 receptors accelerates the satiation process and increases the α-MSH expression in high-fat diet-fed rats.

The knowledge about the role of MC3 receptors (MC3r) in the regulation of feeding behavior is limited. The present study was conducted to determine whether MC3r mediates the hypophagic effects of the melanocortins under conditions of positive energy balance. Male Wistar rats were fed with a high-fat diet (HFD) for 15 days and on day 16 the animals received an intracerebroventricular injection of the following treatments: Vehicle, D-Trp8-γ-melanocyte-stimulating hormone (MSH; MC3r agonist), SHU9119 (MC3r/MC4r antagonist), or D-Trp8-γ-MSH+SHU9119. Food intake was measured and the behavioral satiety sequence (BSS) analysis was carried out during the first hour of the dark phase. The c-Fos and α-MSH immunoreactivity in the arcuate nucleus (ARC) was evaluated 60 min later the onset of food intake. The results indicated that D-Trp8-γ-MSH decreased the ingestion of the HFD and this effect is associated with the early development of the satiation process Moreover, the D-Trp8-γ-MSH increased the accumulation of the α-MSH in the ARC and the c-Fos activity in the PVN. The antagonist SHU9119 partially prevented the D-Trp8-γ-MSH-induced hypophagia. Moreover, behavioral analysis suggests that central activation of MC3r accelerated the cessation of feeding in conditions of positive energy balance; the possible role of MC4r is discussed. Present data indicate that central stimulation of MC3r prevented the overconsumption of the HFD without affecting the natural satiation process, suggesting a potential use of MC3r for the treatment of eating disorders that are stimulated by hypercaloric diets. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Plasma metabolite changes in anestrous dairy cows with negative energy balance identified using 1H NMR technology

ABSTRACT The objective of the present study was to investigate the different plasma metabolites between anestrus and estrus postpartum dairy cows and to provide a theoretical basis for prevention of anestrus in dairy farm cows. In the experiment, one hundred and sixty-seven Holstein dairy cows were selected with similar age and parity. According to the concentration of β-hydroxybutyric acid, non-esterified fatty acids and glucose in plasma during 14 to 21 days in milk, all dairy cows were determined as having a status of energy balance. According to the results of clinical symptom, rectal and B ultrasound examination at 60 to 90 days postpartum, these cows were divided into twenty estrus and twenty-four anestrus group, other dairy cows were removed. 1H nuclear magnetic resonance technology was utilized to detect the plasma metabolites changes and screen different plasma metabolites between anestrus and estrus cows. Ten different metabolites including alanine, glutamic acid, asparagine, creatine, choline, phosphocholine, glycerophosphocholine, low-density lipoprotein, and very-low-density lipoprotein were significantly decreased in anestrous cows compared with estrous cows. Metabolic pathway analyses indicated that differential metabolites were primarily involved in amino acid and glycerophospholipid metabolism. These metabolites and their enrichment pathways indicate that reduced steroid hormone synthesis precursors result in lower levels of estradiol and progesterone and cause anestrus in negative energy balance. These data provide a better understanding of the changes that may affect estrus of postpartum dairy cows at NEB status and lay the ground for further research.

Physical Activity and Total Daily Energy Expenditure in Older US Adults: Constrained versus Additive Models.

This study aimed to examine the shape of the relationship between physical activity (PA) and total energy expenditure (TEE) and to explore the role of energy balance status (negative, stable, positive) in influencing this association. Cross-sectional. Participants were 584 older adults (50-74 yr) participating in the Interactive Diet and Activity Tracking in AARP study. TEE was assessed by doubly labeled water and PA by accelerometer. The relationship between PA and TEE was assessed visually and using nonlinear methods (restricted cubic splines). Percent weight change (>3%) over a 6-month period was used as a proxy measurement of energy balance status. TEE generally increased with increasing deciles of PA averaging 2354 (SD, 351) kcal·d-1 in the bottom decile to 2693 (SD, 480) kcal·d-1 in the top decile. Cubic spline models showed an approximate linear association between PA and TEE (linear relation, P < 0.0001; curvature, P = 0.920). Results were similar in subgroup analyses for individuals classified as stable or positive energy balance. For those in negative energy balance, TEE was generally flat with increasing deciles of PA averaging 2428 (SD, 285) kcal·d-1 in the bottom decile to 2372 (SD, 560) kcal·d-1 in the top decile. Energy balance status seems to play an important role in the relationship between PA and TEE. When in a positive energy balance, the relationship between TEE and PA was consistent with an additive model; however, when energy balance was negative, TEE seems to be consistent with a constrained model. These findings support PA for weight gain prevention by increasing TEE; however, the effect of PA on TEE during periods of weight loss may be limited. An adequately powered, prospective study is warranted to confirm these exploratory findings.

Interlayer interference during coalbed methane coproduction in multilayer superimposed gas-bearing system by 3D monitoring of reservoir pressure: An experimental study

Coproduction is an important measure for improving coalbed methane flow and production efficiency in multilayer superimposed gas-bearing systems. By monitoring the reservoir pressure in 3D spaces, we analyzed the mechanism of fluid migration and interlayer interference during coproduction through a four-layer coproduction experiment with a reservoir pressure gradient of 0.4 MPa. The results revealed the coupling between reservoir pressure gradient, matrix shrinkage, and effective stress, along with their joint effect on the reservoir pressure evolution in stages. The increase in reservoir pressure or reverse gas flow in low-pressure coal seams is the direct manifestation of interlayer interference. This interference increases gradually as the difference between the pressure gradients of the reservoirs increases. The gas elastic energy was modeled considering the free and adsorption states. We found that the difference in gas elastic energies between reservoirs is a major cause of interlayer interference. The wellbore connects coal seams with different reservoir pressures, that is, it connects different energy bodies. This destroys the state of dynamic energy balance between the systems, causing fluid flow from high-energy gas-bearing systems to those with low energy to achieve a new dynamic balance. When the reservoir energy difference is significant, the fluid in higher energy systems shields or inhibits the fluid flow to the wellbore in lower energy systems and may even cause “backflow” to lower energy systems.

Sex and metabolic state interact to influence expression of passive avoidance memory in rats: Potential contribution of A2 noradrenergic neurons

Competing motivational drives coordinate behaviors essential for survival. For example, interoceptive feedback from the body during a state of negative energy balance serves to suppress anxiety-like behaviors and promote exploratory behaviors in rats. Results from past research suggest that this shift in motivated behavior is linked to reduced activation of specific neural populations within the caudal nucleus of the solitary tract (cNTS). However, the potential impact of metabolic state and the potential role of cNTS neurons on conditioned avoidance behaviors has not been examined. The present study investigated these questions in male and female rats, using a task in which rats learn to avoid a context (i.e., a darkened chamber) after it is paired with a single mild footshock. When rats later were tested for passive avoidance of the shock-paired chamber, male rats tested in an overnight food-deprived state and female rats (regardless of feeding status) displayed significantly less avoidance compared to male rats that were fed ad libitum prior to testing. Based on prior evidence that prolactin-releasing peptide (PrRP)-positive noradrenergic neurons and glucagon-like peptide 1 (GLP1)-positive neurons within the cNTS are particularly sensitive to metabolic state, we examined whether these neural populations are activated in conditioned rats after re-exposure to the shock-paired chamber, and whether neural activation is modulated by metabolic state. Compared to the control condition, chamber re-exposure activated PrRP+ noradrenergic neurons and also activated neurons within the anterior ventrolateral bed nucleus of the stria terminalis (vlBNST), which receives dense input from PrRP+ terminals, in both male and female rats when fed ad libitum. In parallel with sex differences in passive avoidance behavior, PrRP+ neurons were less activated in female vs. male rats after chamber exposure. GLP1+ neurons were not activated in either sex. In both sexes, overnight food deprivation before chamber re-exposure reduced activation of PrRP+ neurons, and also reduced vlBNST activation. Our results support the view that PrRP+ noradrenergic neurons and their inputs to the vlBNST contribute to the expression of passive avoidance memory, and that this contribution is modulated by metabolic state.

Explicit transformation between non-adhesive and adhesive contact problems by means of the classical Johnson-Kendall-Roberts formalism.

The classic Johnson-Kendall-Roberts (JKR) contact theory was developed for frictionless adhesive contact between two isotropic elastic spheres. The advantage of the classical JKR formalism is the use of the principle of superposition of solutions to non-adhesive axisymmetric contact problems. In the recent years, the JKR formalism has been extended to other cases, including problems of contact between an arbitrary-shaped blunt axisymmetric indenter and a linear elastic half-space obeying rotational symmetry of its elastic properties. Here the most general form of the JKR formalism using the minimal number of a priori conditions is studied. The corresponding condition of energy balance is developed. For the axisymmetric case and a convex indenter, the condition is reduced to a set of expressions allowing explicit transformation of force-displacement curves from non-adhesive to corresponding adhesive cases. The implementation of the developed theory is demonstrated by presentation of a two-term asymptotic adhesive solution of the contact between a thin elastic layer and a rigid punch of arbitrary axisymmetric shape. Some aspects of numerical implementation of the theory by means of Finite-Element Method are also discussed. This article is part of a discussion meeting issue 'A cracking approach to inventing new tough materials: fracture stranger than friction'.