Space heating and hot water demand analysis of dwellings connected to district heating scheme in UK

To achieve CO2 emissions reductions the UK Building Regulations require developers of new residential buildings to calculate expected CO2 emissions arising from their energy consumption using a methodology such as Standard Assessment Procedure (SAP 2005) or, more recently SAP 2009. SAP encompasses all domestic heat consumption and a limited proportion of the electricity consumption. However, these calculations are rarely verified with real energy consumption and related CO2 emissions. This paper presents the results of an analysis based on weekly head demand data for more than 200 individual flats. The data is collected from recently built residential development connected to a district heating network. A methodology for separating out the domestic hot water use (DHW) and space heating demand (SH) has been developed and compares measured values to the demand calculated using SAP 2005 and 2009 methodologies. The analysis shows also the variance in DHW and SH consumption between both size of the flats and tenure (privately owned or housing association). Evaluation of the space heating consumption includes also an estimation of the heating degree day (HDD) base temperature for each block of flats and its comparison to the average base temperature calculated using the SAP 2005 methodology.

Cannabidivarin is anticonvulsant in mouse and rat in vitro and in seizure models

Summary Background and purpose: Phytocannabinoids in Cannabis sativa have diverse pharmacological targets extending beyond cannabinoid receptors and several exert notable anticonvulsant effects. For the first time, we investigated the anticonvulsant profile of the phytocannabinoid cannabidivarin (CBDV) in vitro and in in vivo seizure models. Experimental approach: The effect of CBDV (1-100μM) on epileptiform local field potentials (LFPs) induced in rat hippocampal brain slices by 4-AP application or Mg2+-free conditions was assessed by in vitro multi-electrode array recordings. Additionally, the anticonvulsant profile of CBDV (50-200 mg kg-1) in vivo was investigated in four rodent seizure models: maximal electroshock (mES) and audiogenic seizures in mice, and pentylenetetrazole (PTZ) and pilocarpine-induced seizures in rat. CBDV effects in combination with commonly-used antiepileptic drugs were investigated in rat seizures. Finally, the motor side effect profile of CBDV was investigated using static beam and gripstrength assays. Key results: CDBV significantly attenuated status epilepticus-like epileptiform LFPs induced by 4-AP and Mg2+-free conditions. CBDV had significant anticonvulsant effects in mES (≥100 mg kg-1), audiogenic (≥50 mg kg-1) and PTZ-induced seizures (≥100 mg kg-1). CBDV alone had no effect against pilocarpine-induced seizures, but significantly attenuated these seizures when administered with valproate or phenobarbital at 200 mg kg-1 CBDV. CBDV had no effect on motor function. Conclusions and Implications: These results indicate that CBDV is an effective anticonvulsant across a broad range of seizure models, does not significantly affect normal motor function and therefore merits further investigation in chronic epilepsy models to justify human trials.

Orexin restores aging-related brown adipose tissue dysfunction in male mice

The aging process causes an increase in percent body fat, but the mechanism remains unclear. In the present study we examined the impact of aging on brown adipose tissue (BAT) thermogenic activity as potential cause for the increase in adiposity. We show that aging is associated with interscapular BAT morphologic abnormalities and thermogenic dysfunction. In vitro experiments revealed that brown adipocyte differentiation is defective in aged mice. Interscapular brown tissue in aged mice is progressively populated by adipocytes bearing white morphologic characteristics. Aged mice fail to mobilize intracellular fuel reserves from brown adipocytes and exhibit deficiency in homeothermy. Our results suggest a role for orexin (OX) signaling in the regulation of thermogenesis during aging. Brown fat dysfunction and age-related assimilation of fat mass were accelerated in mice in which OX-producing neurons were ablated. Conversely, OX injections in old mice increased multilocular morphology, increased core body temperature, improved cold tolerance, and reduced adiposity. These results argue that BAT can be targeted for interventions to reverse age-associated increase in fat mass.

Energy substrate utilization during nightly vocal activity in three species of Scinax (Anura/Hylidae)

Anuran amphibians exhibit different patterns of energy substrate utilization that correlate with the intensity of vocal and locomotor activities. Given the remarkable differences among species in breeding and feeding strategies, and the different ways energy is used in the whole animal, the suggested correlations between calling and locomotor behavior and the level of energy substrates in the muscles responsible for such activities are more complex than previously reported. We explored the relationships between calling and locomotor behavior and energy supply to trunk and hindlimb muscles, respectively, within the ecologically diverse tree-frog genus Scinax. Specifically, we measured the relative amount of carbohydrates and lipids in these two groups of muscles, and in the liver of three species of Scinax that differ in vocal and locomotor performance, and compared our results with those of two other species for which comparable data are available. We also compared the contents of lipids and carbohydrates of conspecific males collected at the beginning and after 4 h of calling activity. The stomach content to potential feeding opportunities across species was also assessed in both groups of males. Scinax hiemalis and S. rizibilis exhibit comparatively low and episodic calling during long periods of activity whereas S. crospedospilus calls at higher rates over shorter periods. Male S. hiemalis had highest levels of trunk muscle glycogen followed by those of S. rizilbilis and S. crospedospilus, respectively. There was no correlation between total lipid content in trunk muscle and calling rate among different species, suggesting that other metabolic aspects may be responsible for the energetic support for vocal activity. The levels of lipids and carbohydrates in trunk and hindlimb muscles and liver of males collected at the beginning and 4 h into the calling period were similar across species, so the extent of energetic reserves does not appear to constrain vocal or locomotor activity. Finally, we found exceptionally high levels of carbohydrates and lipids in the liver of S. rizibilis, a trait perhaps related to a long and demanding breeding period.

(65)Zn(2+) transport by isolated gill epithelial cells of the American lobster, Homarus americanus

Gills are the first site of impact by metal ions in contaminated waters. Work on whole gill cells and metal uptake has not been reported before in crustaceans. In this study, gill filaments of the American lobster, Homarus americanus, were dissociated in physiological saline and separated into several cell types on a 30, 40, 50, and 80% sucrose gradient. Cells from each sucrose solution were separately resuspended in physiological saline and incubated in (65)Zn(2+) in order to assess the nature of metal uptake by each cell type. Characteristics of zinc accumulation by each kind of cell were investigated in the presence and absence of 10 mM calcium, variable NaCl concentrations and pH values, and 100 mu M verapamil, nifedipine, and the calcium ionophore A23187. (65)Zn(2+) influxes were hyperbolic functions of zinc concentration (1-1,000 mu M) and followed Michaelis-Menten kinetics. Calcium reduced both apparent zinc binding affinity (K (m)) and maximal transport velocity (J (max)) for 30% sucrose cells, but doubled the apparent maximal transport velocity for 80% sucrose cells. Results suggest that calcium, sodium, and protons enter gill epithelial cells by an endogenous broad-specificity cation channel and trans-stimulate metal uptake by a plasma membrane carrier system. Differences in zinc transport observed between gill epithelial cell types appear related to apparent affinity differences of the transporters in each kind of cell. Low affinity cells from 30% sucrose were inhibited by calcium, while high affinity cells from 80% sucrose were stimulated. (65)Zn(2+) transport was also studied by isolated, intact, gill filament tips. These intact gill fragments generally displayed the same transport properties as did cells from 80% sucrose and provided support for metal uptake processes being an apical phenomenon. A working model for zinc transport by lobster gill cells is presented.