563 research outputs found

    Sustainable design of terraced houses in Cardiff

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    Global warming is no longer a threat, it has become a reality with significant effects on our communities, our health and our climate. Maintaining comfort in our homes will lead to a higher energy consumption for in-house cooling systems to counteract higher inside temperatures. Unfortunately, different ad-hoc cooling technologies will lead to higher CO2 emissions. This research examines sustainable methods for commonly built residential houses in Cardiff. The building fabric is changed and the simulations indicate that the decrease of Window-to-Wall Ratio is the most effective, followed by a better insulation of building surfaces and adapting shadow devices

    Die Eignung der LeitfĂ€higkeitsmessung zur EutergesundheitsĂŒberwachung bei Milchschafen

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    Sheep milk production is not very common in Germany. Only 10,000 sheep are used for milking. However, a considerable number of farmers work according to the stan-dards of organic farming. Only farm dairies process the milk and sell the products directly to the consumer. Thus, the quality of the raw milk has to be high although the EU regulations for sheep milk are not as strict as for cow’s milk. Animal recording is not a standard in dairy sheep production and farmers lack the information which might be gained by this monthly monitoring of each animal. Animal side tests are necessary and the aim of our study was to investigate the usability of conductivity measurement as an indicator of sub clinical mastitis in ewes. Data were collected from 164 ewes in six organic dairy sheep farms. At first, electrical conductivity (EC) of foremilk was measured to avoid the influence of alveolar milk ejection. Afterwards samples for cyto-bacteriological analyses were gained aseptically. 318 samples could be used for statistical analysis. Prevalence of sub clinical mastitis was low. Only 5.3% of all sam-ples showed a somatic cell count over 100,000 cells per ml in combination with a positive result of the bacteriological investigation. The important pathogens were coagulase-negative staphylococci (79.1% of all positive tested samples). Mean EC was low, but differed significantly between the group of udder halves with normal secretion and with mastitis: 4.9 and 5.5 mS/cm, respectively. The calculation of EC differences between the halves of each udder leaded to the same result: healthy halves had a mean difference of 0.1 mS/cm; 0.4 mS/cm was the difference between healthy and mastitic halves. Nevertheless, the EC difference was to low to use it as an indicator alone. EC measurement can be used to monitor udder health in dairy sheep, but should be carried out on a regular base to achieve reliable results

    Niche differentiation of two sympatric species of Microdochium colonizing the roots of common reed

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    <p>Abstract</p> <p>Background</p> <p>Fungal endophyte communities are often comprised of many species colonizing the same host. However, little is known about the causes of this diversity. On the one hand, the apparent coexistence of closely related species may be explained by the traditional niche differentiation hypothesis, which suggests that abiotic and/or biotic factors mediate partitioning. For endophytes, such factors are difficult to identify, and are therefore in most cases unknown. On the other hand, there is the neutral hypothesis, which suggests that stochastic factors may explain high species diversity. There is a need to investigate to what extent each of these hypotheses may apply to endophytes.</p> <p>Results</p> <p>The niche partitioning of two closely related fungal endophytes, <it>Microdochium bolleyi </it>and <it>M. phragmitis</it>, colonizing <it>Phragmites australis</it>, was investigated. The occurrences of each species were assessed using specific nested-PCR assays for 251 field samples of common reed from Lake Constance, Germany. These analyses revealed niche preferences for both fungi. From three niche factors assessed, i.e. host habitat, host organ and season, host habitat significantly differentiated the two species. <it>M. bolleyi </it>preferred dry habitats, whereas <it>M. phragmitis </it>prevailed in flooded habitats. In contrast, both species exhibited a significant preference for the same host organ, i.e. roots. Likewise the third factor, season, did not significantly distinguish the two species. Differences in carbon utilization and growth temperature could not conclusively explain the niches. The inclusion of three unrelated species of Ascomycota, which also colonize <it>P. australis </it>at the same locations, indicated spatio-temporal niche partitioning between all fungi. None of the species exhibited the same preferences for all three factors, i.e. host habitat, host organ, and time of the season.</p> <p>Conclusions</p> <p>The fungal species colonizing common reed investigated in this study seem to exploit niche differences leading to a separation in space and time, which may allow for their coexistence on the same host. A purely neutral model is unlikely to explain the coexistence of closely related endophytes on common reed.</p

    Transcripts Encoding the Androgen Receptor and IGF-Related Molecules Are Differently Expressed in Human Granulosa Cells From Primordial and Primary Follicles

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    Bidirectional cross talk between granulosa cells and oocytes is known to be important in all stages of mammalian follicular development. Insulin-like growth factor (IGF) signaling is a prominent candidate to be involved in the activation of primordial follicles, and may be be connected to androgen-signaling. In this study, we interrogated transcriptome dynamics in granulosa cells isolated from human primordial and primary follicles to reveal information of growth factors and androgens involved in the physiology of ovarian follicular activation. Toward this, a transcriptome comparison study on primordial follicles (n = 539 follicles) and primary follicles (n = 261 follicles) donated by three women having ovarian tissue cryopreserved before chemotherapy was performed. The granulosa cell contribution in whole follicle isolates was extracted in silico. Modeling of complex biological systems was performed using IPAÂź software. We found the granulosa cell compartment of the human primordial and primary follicles to be extensively enriched in genes encoding IGF-related factors, and the Androgen Receptor (AR) enriched in granulosa cells of primordial follicles. Our study hints the possibility that primordial follicles may indeed be androgen responsive, and that the action of androgens represents a connection to the expression of key players in the IGF-signaling pathway including IGF1R, IGF2, and IGFBP3, and that this interaction could be important for early follicular activation. In line with this, several androgen-responsive genes were noted to be expressed in both oocytes and granulosa cells from human primordial and primary follicle. We present a detailed description of AR and IGF gene activities in the human granulosa cell compartment of primordial and primary follicles, suggesting that these cells may be or prepare to be responsive toward androgens and IGFs

    Highly Efficient siRNA Delivery from Core-Shell Mesoporous Silica Nanoparticles with Multifunctional Polymer Caps

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    A new general route for siRNA delivery is presented combining porous core-shell silica nanocarriers with a modularly designed multifunctional block copolymer. Specifically, the internal storage and release of siRNA from mesoporous silica nanoparticles (MSN) with orthogonal core-shell surface chemistry was investigated as a function of pore-size, pore morphology, surface properties and pH. Very high siRNA loading capacities of up to 380 microg/mg MSN were obtained with charge-matched amino-functionalized mesoporous cores, and release profiles show up to 80% siRNA elution after 24 h. We demonstrate that adsorption and desorption of siRNA is mainly driven by electrostatic interactions, which allow for high loading capacities even in medium-sized mesopores with pore diameters down to 4 nm in a stellate pore morphology. The negatively charged MSN shell enabled the association with a block copolymer containing positively charged artificial amino acids and oleic acid blocks, which acts simultaneously as capping function and endosomal release agent. The potential of this multifunctional delivery platform is demonstrated by highly effective cell transfection and siRNA delivery into KB-cells. A luciferase reporter gene knock-down of up to 90% was possible using extremely low cell exposures with only 2.5 microg MSN containing 32 pM siRNA per 100 microL well.Comment: Artikel including supporting informatio

    Impaired neural networks for approximate calculation in dyscalculic children: a functional MRI study

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    BACKGROUND: Developmental dyscalculia (DD) is a specific learning disability affecting the acquisition of mathematical skills in children with otherwise normal general intelligence. The goal of the present study was to examine cerebral mechanisms underlying DD. METHODS: Eighteen children with DD aged 11.2 ± 1.3 years and twenty age-matched typically achieving schoolchildren were investigated using functional magnetic resonance imaging (fMRI) during trials testing approximate and exact mathematical calculation, as well as magnitude comparison. RESULTS: Children with DD showed greater inter-individual variability and had weaker activation in almost the entire neuronal network for approximate calculation including the intraparietal sulcus, and the middle and inferior frontal gyrus of both hemispheres. In particular, the left intraparietal sulcus, the left inferior frontal gyrus and the right middle frontal gyrus seem to play crucial roles in correct approximate calculation, since brain activation correlated with accuracy rate in these regions. In contrast, no differences between groups could be found for exact calculation and magnitude comparison. In general, fMRI revealed similar parietal and prefrontal activation patterns in DD children compared to controls for all conditions. CONCLUSION: In conclusion, there is evidence for a deficient recruitment of neural resources in children with DD when processing analog magnitudes of numbers

    Subunit rotation in a single FoF1-ATP synthase in a living bacterium monitored by FRET

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    FoF1-ATP synthase is the ubiquitous membrane-bound enzyme in mitochondria, chloroplasts and bacteria which provides the 'chemical energy currency' adenosine triphosphate (ATP) for cellular processes. In Escherichia coli ATP synthesis is driven by a proton motive force (PMF) comprising a proton concentration difference {\Delta}pH plus an electric potential {\Delta}{\Psi} across the lipid membrane. Single-molecule in vitro experiments have confirmed that proton-driven subunit rotation within FoF1-ATP synthase is associated with ATP synthesis. Based on intramolecular distance measurements by single-molecule fluorescence resonance energy transfer (FRET) the kinetics of subunit rotation and the step sizes of the different rotor parts have been unraveled. However, these experiments were accomplished in the presence of a PMF consisting of a maximum {\Delta}pH ~ 4 and an unknown {\Delta}{\Psi}. In contrast, in living bacteria the maximum {\Delta}pH across the plasma membrane is likely 0.75, and {\Delta}{\Psi} has been measured between -80 and -140 mV. Thus the problem of in vivo catalytic turnover rates, or the in vivo rotational speed in single FoF1-ATP synthases, respectively, has to be solved. In addition, the absolute number of functional enzymes in a single bacterium required to maintain the high ATP levels has to be determined. We report our progress of measuring subunit rotation in single FoF1-ATP synthases in vitro and in vivo, which was enabled by a new labeling approach for single-molecule FRET measurements.Comment: 9 pages, 6 figure

    Release of monocyte migration signals by breast cancer cell lines after ablative and fractionated gamma-irradiation

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    Background: Radiotherapy, administered in fractionated as well as ablative settings, is an essential treatment component for breast cancer. Besides the direct tumor cell death inducing effects, there is growing evidence that immune mechanisms contribute - at least in part - to its therapeutic success. The present study was designed to characterize the type and the extent of cell death induced by fractionated and ablative radiotherapy as well as its impact on the release of monocyte migration stimulating factors by dying breast cancer cells. Methods: Cell death and senescence assays were employed to characterize the response of a panel of breast cancer cell lines with different receptor and p53 status towards.-irradiation applied in a fractionated (daily doses of 2 Gy) or ablative setting (single dose of 20 Gy). Cell-free culture supernatants were examined for their monocyte migration stimulating potential in transwell migration and 2D chemotaxis/chemokinesis assays. Irradiation-induced transcriptional responses were analyzed by qRT-PCR, and CD39 surface expression was measured by flow cytometry. Results: Fast proliferating, hormone receptor negative breast cancer cell lines with defective p53 predominantly underwent primary necrosis in response to.-irradiation when applied at a single, ablative dose of 20 Gy, whereas hormone receptor positive, p53 wildtype cells revealed a combination of apoptosis, primary, and secondary (post-apoptotic) necrosis. During necrosis the dying tumor cells released apyrase-sensitive nucleotides, which effectively stimulated monocyte migration and chemokinesis. In hormone receptor positive cells with functional p53 this was hampered by irradiation-induced surface expression of the ectonucleotidase CD39. Conclusions: Our study shows that ablative radiotherapy potently induces necrosis in fast proliferating, hormone receptor negative breast cancer cell lines with mutant p53, which in turn release monocyte migration and chemokinesis stimulating nucleotides. Future studies have to elucidate, whether these mechanisms might be utilized in order to stimulate intra-tumoral monocyte recruitment and subsequent priming of adaptive anti-tumor immune responses, and which breast cancer subtypes might be best suited for such approaches
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