| 1. |
- Fischer, D., et al.
(author)
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Smart meter enabled control for variable speed heat pumps to increase PV self-consumption
- 2015
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In: Refrigeration Science and Technology. - : International Institute of Refrigeration. - 9782362150128 ; , s. 4049-4056
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Conference paper (peer-reviewed)abstract
- In the last five years the costs of photovoltaic systems have decreased considerably making it economically attractive to generate electricity locally. In many countries, self-consumption is the most attractive option to make use of the generated electricity. Variable speed heat pumps - if controlled properly - can take a share of the PV electricity to decrease costs and CO2 emissions for heat generation and increase PV self-consumption. This paper discusses a control strategy that uses real-time smart meter readings and adjusts the compressor speed to adapt heat pump electricity consumption depending on the available PV power. The approach is tested in a detailed building simulation. Self-consumption can be increased by 6% compared to a heat driven control. For the chosen PV size of 10kWp in a German multi-family house, an increase of storage size shows only little possibility for a further increase in self-consumption.
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| 2. |
- Fischer, David, et al.
(author)
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Test cases for hardware in the loop testing of air to water heat pump systems in a smart grid context
- 2015
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In: Refrigeration Science and Technology. - : International Institute of Refrigeration. - 9782362150128 ; , s. 3666-3673
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Conference paper (peer-reviewed)abstract
- Heat Pumps for heating and cooling purposes could play an important role in the future energy system. Combined with a thermal storage they offer the possibility for demand side management applications in a smart grid. Optimized utilization of local solar resources can be achieved by increasingly sophisticated control strategies. Smart gird integration and the use of solar resources will bring new challenges to heat pump system design and operation. However standardized testing procedures to compare HP-systems and controllers in a dynamic and possibly smart grid environment are currently lacking. In this work a method to extract representative test days from energy data, to be used in a Hardware In The Loop test is presented. The resulting sequence of 12 test days is compared to the one year data set and tested in building simulation. Yearly heat generation and SPF can be reproduced with an accuracy of above 94% using the test days.
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| 3. |
- Lopez-Posadas, R., et al.
(author)
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Inhibiting PGGT1B Disrupts Function of RHOA, Resulting in T-cell Expression of Integrin alpha 4 beta 7 and Development of Colitis in Mice
- 2019
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In: Gastroenterology. - : Elsevier BV. - 0016-5085. ; 157:5, s. 1293-1309
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Journal article (peer-reviewed)abstract
- BACKGROUND & AIMS: It is not clear how regulation of T-cell function is altered during development of inflammatory bowel diseases (IBD). We studied the mechanisms by which geranylgeranyltransferase-mediated prenylation controls T-cell localization to the intestine and chronic inflammation. METHODS: We generated mice with T-cell-specific disruption of the geranylgeranyltransferase type I, beta subunit gene (Pggt1b), called Pggt1b(Delta CD4) mice, or the ras homolog family member A gene (Rhoa), called Rhoa(Delta CD4) mice. We also studied mice with knockout of CDC42 or RAC1 and wild-type mice (controls). Intestinal tissues were analyzed by histology, multiphoton and confocal microscopy, and real-time polymerase chain reaction. Activation of CDC42, RAC1, and RHOA were measured with G-LISA, cell fractionation, and immunoblots. T cells and lamina propria mononuclear cells from mice were analyzed by flow cytometry or transferred to Rag1(-/-) mice. Mice were given injections of antibodies against integrin alpha4beta7 or gavaged with the RORC antagonist GSK805. We obtained peripheral blood and intestinal tissue samples from patients with and without IBD and analyzed them by flow cytometry. RESULTS: Pggt1b(Delta CD4) mice developed spontaneous colitis, characterized by thickening of the intestinal wall, edema, fibrosis, accumulation of T cells in the colon, and increased expression of inflammatory cytokines. Compared with control CD4+ T cells, PGGT1B-deficient CD4+ T cells expressed significantly higher levels of integrin alpha4beta7, which regulates their localization to the intestine. Inflammation induced by transfer of PGGT1B-deficient CD4+ T cells to Rag1(-/-) mice was blocked by injection of an antibody against integrin alpha4beta7. Lamina propria of Pggt1b(Delta CD4) mice had increased numbers of CD4+ T cells that expressed RORC and higher levels of cytokines produced by T-helper 17 cells (granulocyte-macrophage colony-stimulating factor, interleukin [IL]17A, IL17F, IL22, and tumor necrosis factor [TNF]). The RORC inverse agonist GSK805, but not antibodies against IL17A or IL17F, prevented colitis in Pggt1b(Delta CD4) mice. PGGT1B-deficient CD4+ T cells had decreased activation of RHOA. RhoA(Delta CD4) mice had a similar phenotype to Pggt1b(Delta CD4) mice, including development of colitis, increased numbers of CD4+ T cells in colon, increased expression of integrin alpha4beta7 by CD4+ T cells, and increased levels of IL17A and other inflammatory cytokines in lamina propria. T cells isolated from intestinal tissues from patients with IBD had significantly lower levels of PGGT1B than tissues from individuals without IBD. CONCLUSION: Loss of PGGT1B from T cells in mice impairs RHOA function, increasing CD4+ T-cell expression of integrin alpha4beta7 and localization to colon, resulting in increased expression of inflammatory cytokines and colitis. T cells isolated from gut tissues from patients with IBD have lower levels of PGGT1B than tissues from patients without IBD.
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| 4. |
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| 5. |
- Philipp, P., et al.
(author)
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Significant Enhancement of Negative Secondary Ion Yields by Cluster Ion Bombardment Combined with Cesium Flooding
- 2015
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 87:19, s. 10025-10032
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Journal article (peer-reviewed)abstract
- In secondary ion mass spectrometry (SIMS), the beneficial effect of cesium implantation or flooding on the enhancement of negative secondary ion yields has been investigated in detail for various semiconductor and metal samples. All results have been obtained for monatomic ion bombardment. Recent progress in SIMS is based to a large extent on the development and use of cluster primary ions. In this work we show that the enhancement of negative secondary ions induced by the combination of ion bombardment with simultaneous cesium flooding is valid not only for monatomic ion bombardment but also for cluster primary ions. Experiments carried out using C60+ and Ar4000+ bombardment on silicon show that yields of negative secondary silicon ions can be optimized in the same way as by Ga+ and Cs+ bombardment. Both for monatomic and cluster ion bombardment, the optimization does not depend on the primary ion species. Hence, it can be assumed that the silicon results are also valid for other cluster primary ions and that results obtained for monatomic ion bombardment on other semiconductor and metal samples are also valid for cluster ion bombardment. In SIMS, cluster primary ions are also largely used for the analysis of organic matter. For polycarbonate, our results show that Ar4000+ bombardment combined with cesium flooding enhances secondary ion signals by a factor of 6. This can be attributed to the removal of charging effects and/or reduced fragmentation, but no major influence on ionization processes can be observed. The use of cesium flooding for the imaging of cells was also investigated and a significant enhancement of secondary ion yields was observed. Hence, cesium flooding has also a vast potential for SIMS analyses with cluster ion bombardment.
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| 6. |
- Weis, J., et al.
(author)
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Sensitivity to change of the EORTC quality of life module measuring cancer-related fatigue (EORTC QlQ-Fa12): Results from the international psychometric validation
- 2019
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In: Psycho-Oncology. - : Wiley. - 1057-9249 .- 1099-1611. ; 28, s. 1753-1761
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Journal article (peer-reviewed)abstract
- Objective The European Organisation for Research and Treatment of Cancer Quality of Life Group (EORTC QLG) has developed a multidimensional instrument measuring cancer-related fatigue, the EORTC QLQ-FA12. The analysis of sensitivity to change is an essential part of psychometric validation. With this study, we investigated the EORTC QLQ-FA12's sensitivity to change. Methods The methodology follows the EORTC guidelines of EORTC QLG for phase IV validation of modules. We included cancer patients undergoing curative and palliative treatment at t1 and followed them up prospectively over the course of their treatment (t2) and 4 weeks after completion of treatment (t3). Data were collected prospectively at 17 sites in 11 countries. Sensitivity to change was investigated using analysis of variance. Results A total sample of 533 patients was enrolled with various tumour types, different stages of cancer, and receiving either curative treatment (n=311) or palliative treatment (n=222). Over time all fatigue scores were significantly higher in the palliative treatment group compared with the curative group (p < .001). Physical fatigue increased with medium effect size over the course of treatment in the curative group (standardized response mean [SRM] (t1,t2) = 0.44]. After treatment physical [SRM (t2,t3) = 0.39], emotional [SRM (t2,t3)= 0.28] and cognitive fatigue (SRM [t2,t3] = 0.22) declined significantly in the curative group. In the palliative group, emotional (SRM [t2,t3] = 0.18) as well as cognitive [SRM [t2,t3] = 0.26) fatigue increases significantly. Conclusions The EORTC-QLQ-FA12 proved to identify clinically significant changes in fatigue in the course of curative and palliative cancer treatment.
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