Diverse and Active Roles for Adipocytes During Mammary Gland Growth and Function

The mammary gland is unique in its requirement to develop in close association with a depot of adipose tissue that is commonly referred to as the mammary fat pad. As discussed throughout this issue, the mammary fat pad represents a complex stromal microenvironment that includes a variety of cell types. In this article we focus on adipocytes as local regulators of epithelial cell growth and their function during lactation. Several important considerations arise from such a discussion. There is a clear and close interrelationship between different stromal tissue types within the mammary fat pad and its adipocytes. Furthermore, these relationships are both stage- and species-dependent, although many questions remain unanswered regarding their roles in these different states. Several lines of evidence also suggest that adipocytes within the mammary fat pad may function differently from those in other fat depots. Finally, past and future technologies present a variety of opportunities to model these complexities in order to more precisely delineate the many potential functions of adipocytes within the mammary glands. A thorough understanding of the role for this cell type in the mammary glands could present numerous opportunities to modify both breast cancer risk and lactation performance

ENERGY EFFICIENCY IN RESIDENTIAL BUILDINGS, LESS STRAIGHT FORWARD THEN PRESUMED

Since the 1990s, the successive EU directives and related national or regional legislations require new construction and retrofits to be as much as possible energy-efficient. Several measures that should stepwise minimize the primary energy use for heating and cooling have become mandated as requirement. However, in reality, related predicted savings are not seen in practice. Two effects are responsible for that. The first one refers to dweller habits, which are more energy-conserving than the calculation tools presume. In fact, while in non-energy-efficient ones, habits on average result in up to a 50% lower end energy use for heating than predicted. That percentage drops to zero or it even turns negative in extremely energy-efficient residences. The second effect refers to problems with low-voltage distribution grids not designed to transport the peaks in electricity whensunny in summer. Through that, a part of converters has to be uncoupled now and then, which means less renewable electricity. This is illustrated by examples that in theory should be net-zero buildings due to the measures applied and the presence of enough photovoltaic cells (PV) on each roof. We can conclude that mandating extreme energy efficiency far beyond the present total optimum value for residential buildings looks questionable as a policy. However, despite that, governments and administrations still seem to require even more extreme measurements regarding energy efficiency

Optimization of energy use for heating/cooling and lighting for a typical office room in a moderate climate

The energy use of an office building consists, apart from services, mainly of heating, cooling and lighting. Ideally, the building design minimizes the total consumption of (primary) energy. However, finding this optimum is not straightforward, since many design decisions have conflicting consequences on lighting energy use and energy use for heating/cooling. In this study, an optimization is performed for a south-facing single person office room in a moderate climate, with primary energy as the criterion. Optimization variables are the U-value of the opaque part of the envelope, the glazing-to-wall-ratio, the shading system, the glazing type and the thermal mass. The daylight availability is calculated using ray-tracing techniques in combination with the daylight coefficient approach. The solar heat gain coefficient of the shading devices is angle dependent and calculated using the WIS software. Building energy simulations are done with TRNSYS, resulting in yearly energy heating and cooling demands. In a first step, daylighting is not taken into account in the optimization. This results in an optimal design with high thermal insulation, low window-to-wall-ratios and a combination of an external and an internal shading device. Secondly, the optimization is redone accounting for daylighting. The results indicate that moderate window-to-wall-ratios, glazing with high visible transmittance and a double shading system ensure the lowest total energy use.status: publishe

Impact of occupant behaviour on lighting energy use

Artificial lighting contributes for a large part to the primary energy use of an office building. Lighting control systems can help reduce the lighting energy use. When calculating the potential energy savings, neglecting the occupant behaviour leads to an overestimation. This research shows that the energy saving performance of a daylight dimming system in an individual office decreases by about 10% when user behaviour is accounted for. A parameter analysis shows that this result is fairly independent of boundary conditions.status: publishe

The influence of soil moisture in the unsaturated zone on the heat loss from buildings via the ground

In calculations of building heat loss via the ground, the coupling with soil moisture transfer is generally ignored, an important hypothesis which will be falsified in this paper. Results from coupled simulations - coupled soil heat and moisture transfer equations and complete surface heat and moisture balances - are compared to results from linear simulations. It is shown that the coupled calculations give notably higher heat losses. Surface temperature, the driving force for heat loss via the ground, is identified as a first important source for these deviations: it is shown that while the averages of the surface temperature are almost equal in coupled and linear calculations, the amplitude in the coupled simulation is considerably higher. A further study reveals that variation of the thermal properties with moisture content also contributes partially to the observed differences. Transfer and storage of sensible heat linked to moisture in the liquid phase was shown to be the last important influencing factor.status: publishe

Energy consumption for heating and rebound effects

When comparing calculated heating consumption in residential buildings assuming standard usage with standardized measured data, then the two typically does not fit. In fact, measured consumption may be a fraction only of what was calculated. The reason is direct rebound behavior by the inhabitants. The paper shows the importance of direct rebound through measured results. First the temperatures, recorded in daytime and sleeping rooms in a sample of dwellings, are commented. Then follows a discussion of the indoor temperatures found when calculated energy consumptions for heating were forced to give the same numbers as measured. Next, two small scale analyses of energy data gained in low-income estates are commented, followed by test results on direct rebound in two dwellings, one non-insulated, the other well insulated. These data prove that the benefits of direct rebound are much larger in non-insulated than in well insulated homes. That fact is used to construct a rebound curve, starting from the normalized consumption data gained in 964 houses. The paper ends by showing the effect of energy price on direct rebound.status: publishe

Determination of the heating efficiency at building level

This paper covers a topic that is often neglected in building energy studies: the interdependency of building, heating system and inhabitants. Practically all calculation methods used to predict the energy performance presume constant efficiencies when assessing the heating system. Numerous studies however show that the whole efficiency of a heating system depends on the load profile and the recoverability of the system losses, which are determined by building insulation, ventilation, thermal capacity and solar heat gains, not to forget the inhabitant behaviour determining the comfort demands and internal gain profile. The results presented in this paper are based on whole building simulations conducted on different dwellings with varying insulation levels and different heating systems. The simulation results show that each heating system combination has a different total efficiency for a certain dwelling and its inhabitants. However, for a given heating system a generalized result produced in function of the monthly ratio between gains and losses of the dwelling. Since the monthly gains to losses ratio is a known variable in an energy performance calculation the dependency function of the heating system efficiency can be added.status: publishe

Impact of refined HVAC systems efficiency determination on EPR energy calculations

status: publishe