838 research outputs found

    Energy audits in a private firm environment: Energy efficiency consultants' cost calculation for innovative technologies in the housing sector

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    During recent international climate negotiations like in Paris 2015, the European Union agreed to reduce the emissions of greenhouse gases. Policy-makers target the residential sector as a major user of fossil energy because potential to improve the energy efficiency in existing houses is observable. Energy audits have been implemented to offer information to homeowners within the aim of reducing the uncertainty concerning energetic refurbishment. Nevertheless, the impact of energy efficiency consultants (EECs) on retrofit measures is described as low in the literature. We conducted an online survey on German EECs, emphasizing their personal attitudes and contextual conditions, analyzing the implementation of an exploratory energy audit and providing recommendations for improving energy audits. The EECs answered the questions regarding the personal factors in a highly confident way. We explain this using the market framework in Germany, which requires a high-level performance due to the competition on the EEC market. The contextual conditions are evaluated critically, with about 49% expressing concerns about acquiring and managing financial resources for energy audits. The case study showed that EECs recommend innovative technologies to a limited degree, while the upfront costs are estimated very low. Finally, in the survey, the respondents prioritized an information policy improvement

    Phylogenetic and comparative gene expression analysis of barley (Hordeum vulgare) WRKY transcription factor family reveals putatively retained functions between monocots and dicots

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    WRKY proteins belong to the WRKY-GCM1 superfamily of zinc finger transcription factors that have been subject to a large plant-specific diversification. For the cereal crop barley (Hordeum vulgare), three different WRKY proteins have been characterized so far, as regulators in sucrose signaling, in pathogen defense, and in response to cold and drought, respectively. However, their phylogenetic relationship remained unresolved. In this study, we used the available sequence information to identify a minimum number of 45 barley WRKY transcription factor (HvWRKY) genes. According to their structural features the HvWRKY factors were classified into the previously defined polyphyletic WRKY subgroups 1 to 3. Furthermore, we could assign putative orthologs of the HvWRKY proteins in Arabidopsis and rice. While in most cases clades of orthologous proteins were formed within each group or subgroup, other clades were composed of paralogous proteins for the grasses and Arabidopsis only, which is indicative of specific gene radiation events. To gain insight into their putative functions, we examined expression profiles of WRKY genes from publicly available microarray data resources and found group specific expression patterns. While putative orthologs of the HvWRKY transcription factors have been inferred from phylogenetic sequence analysis, we performed a comparative expression analysis of WRKY genes in Arabidopsis and barley. Indeed, highly correlative expression profiles were found between some of the putative orthologs. HvWRKY genes have not only undergone radiation in monocot or dicot species, but exhibit evolutionary traits specific to grasses. HvWRKY proteins exhibited not only sequence similarities between orthologs with Arabidopsis, but also relatedness in their expression patterns. This correlative expression is indicative for a putative conserved function of related WRKY proteins in mono- and dicot species

    The “Beam-Me-In Strategy” - remote haptic therapist-patient interaction with two exoskeletons for stroke therapy

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    Background We present a robot-assisted telerehabilitation system that allows for haptic interaction between therapist and patient over distance. It consists of two arm therapy robots. Attached to one robot the therapists can feel on their own arm the limitations of the patient’s arm which is attached to the other robot. Due to the exoskeleton structure of the robot, movements can be performed in the three-dimensional space. Methods Fifteen physical and occupational therapists tested this strategy, named “Beam-Me-In”, while using an exoskeleton robot connected to a second exoskeleton robot in the same room used by the study experimenter. Furthermore, the therapists assessed the level of impairment of recorded and simulated arm movements. They quantified four typical impairments of stroke patients: reduced range of motion (active and passive), resistance to passive movement, a lack of ability to fractionate a movement, and disturbed quality of movement. Results On a Likert Scale (0 to 5 points) therapists rated the “Beam-Me-In” strategy as a very useful medium (mode: 4 points) to evaluate a patient’s progress over time. The passive range of motion of the elbow joint was assessed with a mean absolute error of 4.9∘ (absolute precision error: 6.4∘). The active range of motion of the elbow was assessed with a mean absolute error of 4.9∘ (absolute precision error: 6.5∘). The resistance to passive movement (i.e. modified Tardieu Scale) and the lack of ability to fractionate a movement (i.e. quantification of pathological muscle synergies) was assessed with an inter-rater reliability of 0.930 and 0.948, respectively. Conclusions The “Beam-Me-In” strategy is a promising approach to complement robot-assisted movement training. It can serve as a platform to assess and identify abnormal movement patterns in patients. This is the first application of remote three-dimensional haptic assessmen t applied to telerehabilitation. Furthermore, the “Beam-Me-In” strategy has a potential to overcome barriers for therapists regarding robot-assisted telerehabilitation

    Interplay of superexchange and orbital degeneracy in Cr-doped LaMnO3

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    We report on structural, magnetic and Electron Spin Resonance (ESR) investigations in the manganite system LaMn_{1-x}Cr_{x}O_{3} (x<=0.5). Upon Cr-doping we observe a reduction of the Jahn-Teller distortion yielding less distorted orthorhombic structures. A transition from the Jahn-Teller distorted O' to the pseudocubic O phase occurs between 0.3<x<0.4. A clear connection between this transition and the doping dependence of the magnetic and ESR properties has been observed. The effective moments determined by ESR seem reduced with respect to the spin-only value of both Mn^{3+} and Cr^{3+} ions

    Comparing Arabidopsis receptor kinase and receptor protein-mediated immune signaling reveals BIK1-dependent differences

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    Pattern recognition receptors (PRRs) sense microbial patterns and activate innate immunity against attempted microbial invasions. The leucine‐rich repeat receptor kinases (LRR‐RK) FLS2 and EFR, and the LRR receptor protein (LRR‐RP) receptors RLP23 and RLP42, respectively, represent prototypical members of these two prominent and closely related PRR families. We conducted a survey of Arabidopsis thaliana immune signaling mediated by these receptors to address the question of commonalities and differences between LRR‐RK and LRR‐RP signaling. Quantitative differences in timing and amplitude were observed for several early immune responses, with RP‐mediated responses typically being slower and more prolonged than those mediated by RKs. Activation of RLP23, but not FLS2, induced the production of camalexin. Transcriptomic analysis revealed that RLP23‐regulated genes represent only a fraction of those genes differentially expressed upon FLS2 activation. Several positive and negative regulators of FLS2‐signaling play similar roles in RLP23 signaling. Intriguingly, the cytoplasmic receptor kinase BIK1, a positive regulator of RK signaling, acts as a negative regulator of RP‐type immune receptors in a manner dependent on BIK1 kinase activity. Our study unveiled unexpected differences in two closely related receptor systems and reports a new negative role of BIK1 in plant immunity

    pH-dependent structural transitions in cationic ionizable lipid mesophases are critical for lipid nanoparticle function

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    Lipid nanoparticles (LNPs) are advanced core-shell particles for messenger RNA (mRNA) based therapies that are made of polyethylene glycol (PEG) lipid, distearoylphosphatidylcholine (DSPC), cationic ionizable lipid (CIL), cholesterol (chol), and mRNA. Yet the mechanism of pH-dependent response that is believed to cause endosomal release of LNPs is not well understood. Here, we show that eGFP (enhanced green fluorescent protein) protein expression in the mouse liver mediated by the ionizable lipids DLin-MC3-DMA (MC3), DLin-KC2-DMA (KC2), and DLinDMA (DD) ranks MC3 ≄ KC2 > DD despite similar delivery of mRNA per cell in all cell fractions isolated. We hypothesize that the three CIL-LNPs react differently to pH changes and hence study the structure of CIL/chol bulk phases in water. Using synchrotron X-ray scattering a sequence of ordered CIL/chol mesophases with lowering pH values are observed. These phases show isotropic inverse micellar, cubic Fd3m inverse micellar, inverse hexagonal and bicontinuous cubic Pn3m symmetry. If polyadenylic acid, as mRNA surrogate, is added to CIL/chol, excess lipid coexists with a condensed nucleic acid lipid phase. The next-neighbor distance in the excess phase shows a discontinuity at the Fd3m inverse micellar to inverse hexagonal transition occurring at pH 6 with distinctly larger spacing and hydration for DD vs. MC3 and KC2. In mRNA LNPs, DD showed larger internal spacing, as well as retarded onset and reduced level of DD-LNP-mediated eGFP expression in vitro compared to MC3 and KC2. Our data suggest that the pH-driven Fd3m- transition in bulk phases is a hallmark of CIL-specific differences in mRNA LNP efficacy.publishedVersio

    Quantum transport through STM-lifted single PTCDA molecules

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    Using a scanning tunneling microscope we have measured the quantum conductance through a PTCDA molecule for different configurations of the tip-molecule-surface junction. A peculiar conductance resonance arises at the Fermi level for certain tip to surface distances. We have relaxed the molecular junction coordinates and calculated transport by means of the Landauer/Keldysh approach. The zero bias transmission calculated for fixed tip positions in lateral dimensions but different tip substrate distances show a clear shift and sharpening of the molecular chemisorption level on increasing the STM-surface distance, in agreement with experiment.Comment: accepted for publication in Applied Physics

    Pressure-based lift estimation and its application to feedforward load control employing trailing-edge flaps

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    This experimental load control study presents results of an active trailing-edge flap feedforward controller for wind turbine applications. The controller input is derived from pressure-based lift estimation methods that rely either on a quasi-steady method, based on a three-hole probe, or on an unsteady method that is based on three selected surface pressure ports. Furthermore, a standard feedback controller, based on force balance measurements, is compared to the feedforward control. A Clark-Y airfoil is employed for the wing that is equipped with a trailing-edge flap of x/c=30% chordwise extension. Inflow disturbances are created by a two-dimensional active grid. The Reynolds number is Re=290 000, and reduced frequencies of k=0.07 up to k=0.32 are analyzed. Within the first part of the paper, the lift estimation methods are compared. The surface-pressure-based method shows generally more accurate results, whereas the three-hole probe estimate overpredicts the lift amplitudes with increasing frequencies. Nonetheless, employing the latter as input to the feedforward controller is more promising as a beneficial phase lead is introduced by this method. A successful load alleviation was achieved up to reduced frequencies of k=0.192.DFG, 218736457, Experimentelle Untersuchung von Strömungskontrollmethoden zur Lastkontrolle an Windkraftanlagen mittels einer Forschungswindkraftanlage im WindkanalDFG, 414044773, Open Access Publizieren 2021 - 2022 / Technische UniversitĂ€t Berli
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