uu.seUppsala University Publications
1 - 10 of 10
rss atomLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
  • Public defence: 2018-08-21 13:00 B42, Uppsala
    Pilia, Giulia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Ludwig Institute for Cancer Research, Uppsala.
    Novel Roles of the Ack1 Kinase in Epithelial Biology2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Epithelial homeostasis is maintained through integration of diverse signals that regulate cell fate. A strict control of such signals is required to prevent overproliferation and, ultimately, oncogenesis. In this thesis we identify novel roles of Activated Cdc42-associated kinase 1 (Ack1) in maintenance of epithelial homeostasis. Ack1 has been previously linked to cytoskeletal remodeling, signal transduction and gene expression regulation. Interestingly, our work reveals that Ack1 is also important for I) promoting extrinsic apoptosis, II) mediating mechanically-induced inhibition of proliferation and III) attenuating mitogenic signals, fundamental functions to prevent aberrant tissue growth.

    Apoptosis is a program of regulated cell death that can be triggered by several pathways. Among them, the TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis cascade has raised interest for cancer treatment, as many cancer cell lines are susceptible to it. We found that Ack1 increases sensitivity to TRAIL by promoting translocation of ligand-bound TRAIL-Receptor to lipid rafts. Localisation at the lipid rafts, in turn, favors recruitment of downstream signalling effectors, enhancing the apoptotic response.

    Yap and Taz are transcriptional co-factors that integrate mechanical and soluble cues to regulate cell proliferation and differentiation. Yap/Taz regulation is mediated by cytoplasmic sequestration and, particularly for Taz, proteasomal degradation via ubiquitination by the E3 ligase β-TrCP. We discovered that Ack1 is activated by mechanical signals and promotes nuclear exclusion of Yap/Taz. Ack1 promotes Yap/Taz interaction with β-TRCP and it is required for efficient degradation of Taz. Consequently, Ack1 limits Yap/Taz-dependent gene expression and cell proliferation.

    The ErbB family of receptor tyrosine kinases mediates pro-survival and proliferative signals of crucial importance in development and cancer. Among the ErbB family members, ErbB3 has significant oncogenic properties as it potently activates the PI3K/Akt signaling pathway. We observe that Ack1 depletion increases ErbB3 total levels, but not EGFR and ErbB2, and is required for both basal turnover of ErbB3 and its ligand-induced degradation. Consequently, Ack1 attenuates ErbB3-dependent signalling upon Neuregulin-1β treatment. Additionally, Ack1 reduces ErbB3 gene expression both at steady state and upon stimulation, revealing its importance as multi-level regulator of ErbB3.

    Taken together, our data depict new roles for Ack1 in epithelial cells, highlighting its multifaceted role in maintenance of epithelial homeostasis.

    List of papers
    1. Activated Cdc42-associated Kinase 1 (Ack1) Is Required for Tumor Necrosis Factor-related Apoptosis-inducing Ligand (TRAIL) Receptor Recruitment to Lipid Rafts and Induction of Cell Death
    Open this publication in new window or tab >>Activated Cdc42-associated Kinase 1 (Ack1) Is Required for Tumor Necrosis Factor-related Apoptosis-inducing Ligand (TRAIL) Receptor Recruitment to Lipid Rafts and Induction of Cell Death
    2013 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 288, no 46, p. 32922-32931Article in journal (Refereed) Published
    Abstract [en]

    TNF-related apoptosis-inducing ligand (TRAIL) holds promise for treatment of cancer due to its ability to selectively kill cancer cells while sparing normal cells. Ligand-induced translocation of TRAIL receptors (TRAIL-R) 1 and 2 (also called DR4 and DR5, respectively) into lipid raft membrane microdomains is required for TRAIL-induced cell death by facilitating receptor clustering and formation of the death-inducing signaling complex, yet the underlying regulatory mechanisms remain largely unknown. We show here that the non-receptor tyrosine kinase Ack1, previously implicated in the spatiotemporal regulation of the EGF receptor, is required for TRAIL-induced cell death in multiple epithelial cell lines. TRAIL triggered a transient up-regulation of Ack1 and its recruitment to lipid rafts along with TRAIL-R1/2. siRNA-mediated depletion of Ack1 disrupted TRAIL-induced accumulation of TRAIL-R1/2 in lipid rafts and efficient recruitment of caspase-8 to the death-inducing signaling complex. Pharmacological inhibition of Ack1 did not affect TRAIL-induced cell death, indicating that Ack1 acts in a kinase-independent manner to promote TRAIL-R1/2 accumulation in lipid rafts. These findings identify Ack1 as an essential player in the spatial regulation of TRAIL-R1/2.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:uu:diva-212597 (URN)10.1074/jbc.M113.481507 (DOI)000328841700010 ()24085293 (PubMedID)
    Funder
    Swedish Cancer Society, CAN 2012/581NIH (National Institute of Health), 1R01CA135328
    Available from: 2013-12-12 Created: 2013-12-12 Last updated: 2018-04-26Bibliographically approved
    2. ACK1 is a mechanoresponsive kinase required for SCF (β-TrCP)-mediated degradation of YAP/TAZ
    Open this publication in new window or tab >>ACK1 is a mechanoresponsive kinase required for SCF (β-TrCP)-mediated degradation of YAP/TAZ
    (English)Manuscript (preprint) (Other academic)
    National Category
    Cell and Molecular Biology
    Identifiers
    urn:nbn:se:uu:diva-349179 (URN)
    Available from: 2018-04-23 Created: 2018-04-23 Last updated: 2018-04-26
    3. Ack1 is a negative regulator of ErbB3 that acts both by promoting its degradation and suppressing its expression
    Open this publication in new window or tab >>Ack1 is a negative regulator of ErbB3 that acts both by promoting its degradation and suppressing its expression
    (English)Manuscript (preprint) (Other academic)
    National Category
    Cell and Molecular Biology
    Identifiers
    urn:nbn:se:uu:diva-349182 (URN)
    Available from: 2018-04-23 Created: 2018-04-23 Last updated: 2018-04-26
  • Public defence: 2018-08-24 13:00 Rudbecksalen, Uppsala
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Clinical Immunology.
    Characterization of the Pancreas in Type 1 and Type 2 Diabetes2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Diabetes is recognized by hyperglycaemia and polyuria. Complications, reduced quality of life and staggering health-care costs are all derived from the disease. Two subclasses of diabetes are Type 1 diabetes (T1D) and Type 2 diabetes (T2D). The beta cell mass is reduced in T1D, which is generally considered to be caused by an immune-mediated beta-cell destruction, but definitive evidence for this hypothesis remains absent. Development of insulin resistance and dysfunctional beta cells are commonly recognized as important factors that contribute to fulminant T2D. The literature that describes human T1D and T2D pancreata is sparse due to the limited number of specimens available for study. If more features of the respective pancreata are described, we might be able to elucidate the mechanisms involved in the pathoaetiology of the diseases.

    Accordingly, in this thesis pancreatic biopsies obtained from subjects with T1D or T2D have been examined with the aim to provide a more comprehensive picture of the respective pancreata. Paper I reports that aggregates of leucocytes substantiated mostly by macrophages are present in several T2D pancreata. Furthermore, as 28% of the T2D pancreata met the consensus definition of insulitis developed for T1D, a redefinition of insulitis is proposed. In Paper II, the density of parasympathetic axons was found to be reduced in the exocrine compartment in recent-onset T1D subjects compared to non-diabetic and long-standing T1D subjects. However, no alteration was discovered in islet-associated parasympathetic axons. In Paper III, interferon-stimulated genes were found to be over-expressed in recent-onset T1D islets, but no inducer explaining this expression has been discovered. Paper IV shows that T2D islets exhibit a stress response on a transcriptional level, and expression of these genes were investigated in islets from subjects with elevated HbA1c levels but without a clinical T2D diagnosis.

    In conclusion, this thesis explores several new areas of the pancreas in both T1D and T2D, and demonstrate several important findings that increase our knowledge on how diabetes develops.

    List of papers
    1. Insulitis in human diabetes: a histological evaluation of donor pancreases
    Open this publication in new window or tab >>Insulitis in human diabetes: a histological evaluation of donor pancreases
    Show others...
    2017 (English)In: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 60, no 2, p. 346-353Article in journal (Refereed) Published
    Abstract [en]

    Aims/hypothesis According to the consensus criteria developed for type 1 diabetes, an individual can be diagnosed with insulitis when >= 15 CD45(+) cells are found within the parenchyma or in the islet-exocrine interface in >= 3 islets. The aim of this study was to determine the frequency of individuals with type 2 diabetes fulfilling these criteria with reference to non-diabetic and type 1 diabetic individuals. Methods Insulitis was determined by examining CD45(+) cells in the pancreases of 50, 13 and 44 organ donors with type 2 diabetes, type 1 diabetes and no diabetes, respectively. CD3(+) cells (T cells) infiltrating the islets were evaluated in insulitic donors. In insulitic donors with type 2 diabetes, the pancreases were characterised according to the presence of CD68 (macrophages), myeloperoxidase (MPO; neutrophils), CD3, CD20 (B cells) and HLA class I hyperstained islets. In all type 2 diabetic donors, potential correlations of insulitis with dynamic glucose-stimulated insulin secretion in vitro or age, BMI, HbA(1c) or autoantibody positivity were examined. Results Overall, 28% of the type 2 diabetic donors fulfilled the consensus criteria for insulitis developed for type 1 diabetes. Of the type 1 diabetic donors, 31% fulfilled the criteria. None of the non-diabetic donors met the criteria. Only type 1 diabetic donors had >= 15 CD3(+) cells in >= 3 islets. Type 2 diabetic donors with insulitis also had a substantial number of CD45(+) cells in the exocrine parenchyma. Macrophages constituted the largest fraction of CD45(+) cells, followed by neutrophils and T cells. Of type 2 diabetic pancreases with insulitis, 36% contained islets that hyperstained for HLA class I. Isolated islets from type 2 diabetic donors secreted less insulin than controls, although with preserved dynamics. Insulitis in the type 2 diabetic donors did not correlate with glucose-stimulated insulin secretion, the presence of autoantibodies, BMI or HbA(1c). Conclusions/interpretation The current definition of insulitis cannot be used to distinguish pancreases retrieved from individuals with type 1 diabetes from those with type 2 diabetes. On the basis of our findings, we propose a revised definition of insulitis, with a positive diagnosis when >= 15 CD3(+) cells, not CD45(+) cells, are found in >= 3 islets.

    Keywords
    HLA, Inflammation, Insulin secretion, Insulitis, Islets, Macrophages, Tcells, Type 1 diabetes, Type 2 diabetes
    National Category
    Endocrinology and Diabetes
    Identifiers
    urn:nbn:se:uu:diva-315054 (URN)10.1007/s00125-016-4140-z (DOI)000391359800016 ()27796420 (PubMedID)
    Funder
    EU, FP7, Seventh Framework Programme, 261441 PEVNETNovo NordiskÅke Wiberg FoundationSwedish Diabetes Association
    Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2018-05-02Bibliographically approved
    2. The density of parasympathetic axons is reduced in the exocrine pancreas of individuals recently diagnosed with type 1 diabetes
    Open this publication in new window or tab >>The density of parasympathetic axons is reduced in the exocrine pancreas of individuals recently diagnosed with type 1 diabetes
    Show others...
    2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 6, article id e0179911Article in journal (Refereed) Published
    Abstract [en]

    To elucidate the etiology of type 1 diabetes, the affected pancreas needs to be thoroughly characterized. Pancreatic innervation has been suggested to be involved in the pathology of the disease and a reduction of sympathetic innervation of the islets was recently reported. In the present study, we hypothesized that parasympathetic innervation would be altered in the type 1 diabetes pancreas. Human pancreatic specimens were obtained from a unique cohort of individuals with recent onset or long standing type 1 diabetes. Density of parasympathetic axons was assessed by immunofluorescence and morphometry. Our main finding was a reduced density of parasympathetic axons in the exocrine, but not endocrine compartment of the pancreas in individuals with recent onset type 1 diabetes. The reduced density of parasympathetic axons in the exocrine compartment could have functional implications, e.g. be related to the exocrine insufficiency reported in type 1 diabetes patients. Further studies are needed to understand whether reduced parasympathetic innervation is a cause or consequence of type 1 diabetes.

    Place, publisher, year, edition, pages
    PUBLIC LIBRARY SCIENCE, 2017
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:uu:diva-330731 (URN)10.1371/journal.pone.0179911 (DOI)000404043100049 ()28628651 (PubMedID)
    Funder
    Novo NordiskEU, FP7, Seventh Framework Programme, 261441 PEVNETSwedish Child Diabetes FoundationSwedish Research Council, 65X-12219-15-6, K2015-54X-12219-19-4, 2008-4216, 521-2012-2119Swedish Diabetes AssociationMagnus Bergvall Foundation
    Available from: 2017-10-10 Created: 2017-10-10 Last updated: 2018-05-02Bibliographically approved
    3. Expression of Interferon-Stimulated Genes in Insulitic Pancreatic Islets of Patients Recently Diagnosed With Type 1 Diabetes
    Open this publication in new window or tab >>Expression of Interferon-Stimulated Genes in Insulitic Pancreatic Islets of Patients Recently Diagnosed With Type 1 Diabetes
    Show others...
    2016 (English)In: Diabetes, ISSN 0012-1797, E-ISSN 1939-327X, Vol. 65, no 10, p. 3104-3110Article in journal (Refereed) Published
    Abstract [en]

    A primary insult to the pancreatic islets of Langerhans, leading to the activation of innate immunity, has been suggested as an important step in the inflammatory process in type 1 diabetes (T1D). The aim of this study was to examine whether interferon (IFN)-stimulated genes (ISGs) are overexpressed in human T1D islets affected with insulitis. By using laser capture microdissection and a quantitative PCR array, 23 of 84 examined ISGs were found to be overexpressed by at least fivefold in insulitic islets from living patients with recent-onset T1D, participating in the Diabetes Virus Detection (DiViD) study, compared with islets from organ donors without diabetes. Most of the overexpressed ISGs, including GBP1, TLR3, OAS1, EIF2AK2, HLA-E, IFI6, and STAT1, showed higher expression in the islet core compared with the peri-islet area containing the surrounding immune cells. In contrast, the T-cell attractant chemokine CXCL10 showed an almost 10-fold higher expression in the peri-islet area than in the islet, possibly partly explaining the localization of T cells mainly to this region. In conclusion, insulitic islets from recent-onset T1D subjects show overexpression of ISGs, with an expression pattern similar to that seen in islets infected with virus or exposed to IFN-gamma/interleukin-1 beta or IFN-alpha.

    National Category
    Endocrinology and Diabetes
    Identifiers
    urn:nbn:se:uu:diva-311223 (URN)10.2337/db16-0616 (DOI)000388372900029 ()27422384 (PubMedID)
    Funder
    Novo NordiskSwedish Research Council, K2011-65X-12219-15-6, K2015-54X-12219-19-4Åke Wiberg FoundationSwedish Diabetes AssociationSwedish Child Diabetes FoundationEXODIAB - Excellence of Diabetes Research in Sweden
    Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2018-05-02Bibliographically approved
    4. Expression profiles of stress-related genes in islets from donors with progressively impaired glucose metabolism.
    Open this publication in new window or tab >>Expression profiles of stress-related genes in islets from donors with progressively impaired glucose metabolism.
    Show others...
    2018 (English)In: Islets, ISSN 1938-2014, E-ISSN 1938-2022, Vol. 10, no 2, p. 69-79Article in journal (Refereed) Published
    Abstract [en]

    It is currently unknown how the islet transcriptional pattern changes as glucose metabolism deteriorates and progresses to fulminant type 2 diabetes (T2D). In this study, we hypothesized that islets from donors with elevated HbA1c levels, but not yet diagnosed with T2D, would show signs of cell stress on a transcriptional level. Laser capture microdissection and qPCR arrays including 330 genes related to mitochondria, oxidative stress, or the unfolded protein response were used to extract and analyze islets from organ donors with HbA1c <5.5% (37 mmol/mol), elevated HbA1c (6.0-6.5% (42-48 mmol/mol)), high HbA1c (>6.5% (48 mmol/mol)) or established T2D. Principal component analysis and hierarchical clustering based on the expression of all 330 genes displayed no obvious separation of the four different donor groups, indicating that the inter-donor variations were larger than the differences between groups. However, 44 genes were differentially expressed (P < 0.05, false discovery rate <30%) between islets from donors with HbA1c <5.5% (37 mmol/mol) compared with islets from T2D subjects. Twelve genes were differentially expressed compared to control islets in both donors with established T2D and donors with elevated HbA1c (6.0-6.5% (42-48 mmol/mol)). Overexpressed genes were related mainly to the unfolded protein response, whereas underexpressed genes were related to mitochondria. Our data on transcriptional changes in human islets retrieved by LCM from high-quality biopsies, as pre-diabetes progresses to established T2D, increase our understanding on how islet stress contributes to the disease development.

    Keywords
    HbA1c, laser capture, transcriptome, type 2 diabetes
    National Category
    Endocrinology and Diabetes
    Identifiers
    urn:nbn:se:uu:diva-342882 (URN)10.1080/19382014.2018.1433980 (DOI)000428814700003 ()29446696 (PubMedID)
    Funder
    Swedish Research Council, 65X-12219-15-6, K2015-54X-12219-19-4Novo NordiskÅke Wiberg FoundationTore Nilsons Stiftelse för medicinsk forskningMagnus Bergvall FoundationErnfors FoundationSwedish Child Diabetes FoundationSwedish Diabetes Association
    Available from: 2018-02-23 Created: 2018-02-23 Last updated: 2018-06-04Bibliographically approved
  • Public defence: 2018-08-31 09:00 Rudbecksalen, Uppsala
    Åström, Lennart
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Experimental and Clinical Oncology.
    Dose Escalation with High Dose Rate Brachytherapy or Protons in Curative Radiotherapy of Prostate Cancer2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of the thesis was to study the outcome and side effects after dose-escalated radiotherapy with high dose rate brachytherapy (HDR-BT) or proton beam therapy (PBT) boost in prostate cancer.

    The first cohorts of men in Sweden treated with either HDR-BT or PBT in combination with conventional photon beam therapy (2 Gray (Gy) fractions to 50 Gy) were analysed. The HDR-BT was given with two 10 Gy fractions, and the PBT with four fractions of 5 Gy. The analyses included 823 men in two HDR-BT cohorts, and 265 men in the PBT cohort. A large proportion of the cohorts, from 38% to 53%, were classified as high risk. After a follow-up between four and eleven years, both combinations showed low risks for relapse. The overall 5-year risk for PSA relapse was 0% for men with low risk. After PBT, the 5-year PSA relapse risk for intermediate and high risk were 5% and 26% respectively. After HDR-BT the 10-year risks for PSA relapse were 0%, 21% and 33% for low, intermediate, and high risk, respectively.

    The risk for early and late toxicity was low. Genitourinary (GU) toxicity was more frequent than gastrointestinal (GI) toxicity. GU toxicity may have a late onset and progress slowly with time after HDR-BT. The 5- and 10-year actuarial incidences of urethral stricture were 6% and 10% respectively after HDR-BT. With applied dose constraints to the urethra the 10-year risk was 5%. The actuarial prevalence of GI toxicity declined slowly with time after HDR-BT as well as after PBT.

    A PSA bounce after HDR-BT was seen in 26% of the patients, more frequent with younger age and lower Gleason score, and followed by a low risk for relapse.

    For dose-escalated radiotherapy with HDR-BT or PBT:

    • long-term tumour control was achieved, not only for low- and intermediate risk, but also for the majority of high risk patients,
    • a PSA bounce after HDR-BT was folled by a good prognosis,
    • levels of late toxicity were low,
    • genitourinary toxicity was more frequent than gastrointestinal toxicity,
    • dose constraints to risk organs must be applied to minimise risks for late toxicity.
    List of papers
    1. Long-term outcome of high dose rate brachytherapy in radiotherapy of localised prostate cancer
    Open this publication in new window or tab >>Long-term outcome of high dose rate brachytherapy in radiotherapy of localised prostate cancer
    Show others...
    2005 (English)In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 74, no 2, p. 157-61Article in journal (Refereed) Published
    Abstract [en]

    Background and purpose: High dose rate brachytherapy (HDR-BT) in prostate cancer (PC) is receiving increasing interest. The steep dose gradient gives a possibility to escalate the dose to the prostate. If the a/b ratio is low for PC, hypofractionation will be of advantage. A retrospective analysis of outcome in patients (pts) consecutively treated with combined HDR-BT and conformal external beam radiotherapy (ERT) was performed. Material and methods: Data from 214 pts treated consecutively from 1988 to 2000 were analysed. The median age was 64 years (50–77). Median follow up was 4 years (12–165 months). Pre-irradiatory endocrine therapy was given to 150 pts (70%). The pts were divided into low-, intermediate- and high (80/87/47 pts) risk groups according to the occurrence of none, one, or more risk factors defined by T-classification, PSA and histopathology. ERT was given with 2 Gy fractions to 50 Gy. HDR-BT consisted of two 10 Gy fractions. Results: Overall 5-year biochemical no evidence of disease (bNED) was 82%, and for the low-, intermediate-, and high-risk group bNED was 92, 88 and 61%, respectively. PSA-relapse was found in 17, local recurrence in 3 and distant metastases in 13 pts. Five pts died of PC. No recurrences were observed after 5 years. Severe late complications were few. Urethral stricture (13 pts) was the most frequent. No severe rectal complications were seen. Conclusion: Dose escalation with HDR-BT is safe and effective in radiotherapy of localised PC.

    Keywords
    Prostate cancer, Radiotherapy, Brachytherapy, High dose rate
    National Category
    Cancer and Oncology
    Identifiers
    urn:nbn:se:uu:diva-72860 (URN)10.1016/j.radonc.2004.10.014 (DOI)15734203 (PubMedID)
    Available from: 2006-06-29 Created: 2006-06-29 Last updated: 2018-05-08Bibliographically approved
    2. Hypofractionated proton boost combined with external beam radiotherapy for treatment of localized prostate cancer
    Open this publication in new window or tab >>Hypofractionated proton boost combined with external beam radiotherapy for treatment of localized prostate cancer
    Show others...
    2012 (English)In: Prostate Cancer, ISSN 2090-3111, E-ISSN 2090-312X, Vol. 2012, article id 654861Article in journal (Refereed) Published
    Abstract [en]

    Proton boost of 20 Gy in daily 5 Gy fractions followed by external beam radiotherapy (EBRT) of 50 Gy in daily 2 Gy fractions were given to 278 patients with prostate cancer with T1b to T4N0M0 disease. Fifty-three percent of the patients received neoadjuvant androgen deprivation therapy (N-ADT). The medium followup was 57 months. The 5-year PSA progression-free survival was 100%, 95%, and 74% for low-, intermediate-, and high-risk patients, respectively. The toxicity evaluation was supported by a patient-reported questionnaire before every consultant visit. Cumulative probability and actuarial prevalence of genitourinary (GU) and gastrointestinal (GI) toxicities are presented according to the RTOG classification. N-ADT did not influence curability. Mild pretreatment GU-symptoms were found to be a strong predictive factor for GU-toxicity attributable to treatment. The actuarial prevalence declined over 3 to 5 years for both GU and GI toxicities, indicating slow resolution of epithelial damage to the genitourinary and gastrointestinal tract. Bladder toxicities rather than gastrointestinal toxicities seem to be dose limiting. More than 5-year followup is necessary to reveal any sign of true progressive late side effects of the given treatment. Hypofractionated proton-boost combined with EBRT is associated with excellent curability of localized PC and acceptable frequencies of treatment toxicity.

    National Category
    Cancer and Oncology
    Identifiers
    urn:nbn:se:uu:diva-347410 (URN)10.1155/2012/654861 (DOI)22848840 (PubMedID)
    Available from: 2018-03-31 Created: 2018-03-31 Last updated: 2018-05-08Bibliographically approved
    3. Two decades of high dose rate brachytherapy with external beam radiotherapy for prostate cancer
    Open this publication in new window or tab >>Two decades of high dose rate brachytherapy with external beam radiotherapy for prostate cancer
    Show others...
    2018 (English)In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, article id S0167-8140(17)32780-9Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    BACKGROUND: High-dose-rate brachytherapy (HDR-BT) has optimal prerequisites in radiotherapy of prostate cancer (PC) with a conformal dose distribution and high doses per fraction giving a biological dose escalation. We report the outcome after HDR-BT and external beam radiotherapy (EBRT) after 20 years of experience.

    MATERIAL AND METHODS: The study includes 623 patients, median age of 66 years, treated from 1995 to 2008 and a median follow up of 11 years (range 2-266 months). Androgen deprivation therapy was given to 429 patients (69%). The HDR-BT was given with two 10 Gy fractions and the EBRT with 2 Gy fractions to 50 Gy.

    RESULTS: The 10-year PC-specific survival was 100%, 92%, 91%, and 75% for low-, intermediate-, high- and very high-risk patients respectively, and the 10-year probability of PSA relapse was 0%, 21%, 33%, and 65% respectively. The 10-year actuarial prevalence for ≥grade 2 GU- and GI-toxicities were 28% and 12% respectively and for ≥grade 3, 4% and 1% respectively. Urethral stricture was the most frequent GU complication with a 10-year actuarial incidence of 10%. Treatment without dose constraints for the urethra conferred a higher incidence 18%, compared to 5% after 2003 (p < 0.001). Sixteen patients experienced grade 4 GU toxicity, of which 13 were treated before 2003. No grade 4 rectal toxicity was seen.

    CONCLUSION: The combination of EBRT and HDR-BT with adequate dose constraints to risk organs provides satisfactory long-term tumour control even in high-risk patients. GI toxicity stabilised but GU toxicity progressed during the 10-year follow up.

    Keywords
    Brachytherapy, High dose rate, Prostate cancer, Radiotherapy
    National Category
    Cancer and Oncology
    Identifiers
    urn:nbn:se:uu:diva-347411 (URN)10.1016/j.radonc.2017.12.025 (DOI)29496280 (PubMedID)
    Available from: 2018-03-31 Created: 2018-03-31 Last updated: 2018-05-08Bibliographically approved
    4. Good Prognosis following a PSA Bounce after High Dose Rate Brachytherapy with External Radiotherapy in Prostate Cancer.
    Open this publication in new window or tab >>Good Prognosis following a PSA Bounce after High Dose Rate Brachytherapy with External Radiotherapy in Prostate Cancer.
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Background

    PSA kinetics after curative radiotherapy for prostate cancer is an important part of the posttreatment evaluation. We analysed PSA bounce occurrence after combined high dose rate brachytherapy (HDR-BT) and external radiotherapy (ERT).

    Material & methods

    We analysed 623 patients treated from 1995 to 2008. The median age was 66 years (47-79). The median initial PSA was 12 ng/ml (0.1-224). Neoadjuvant endocrine therapy was given to 429 patients. ERT was given with 2 Gy fractions to 50 Gy and HDR-BT in two 10 Gy fractions. The median follow-up was 11 years (range 2-266 months). PSA bounce was defined as a temporary rise in PSA >0.2 ng/ml. PSA failure was defined according to the Phoenix definition.

    Results

    PSA bounce occurred in 159 patients (26%), where 56 patients had a bounce amplitude >2 ng/ml and 31 patients had multiple bounces. Median time to bounce peak was 15 (3-103) months with a median bounce value of 1.5 (0.3-12) ng/ml. Younger age and lower Gleason scores were associated with PSA bounce. In a Cox regression analysis with PSA bounce as a time-dependent covariate and adjusted for other prognostic factors, PSA bounce was associated with a lower risk for PSA failure (HR=0.42; 95% confidence interval 0.26-0.70).

    Conclusion

    PSA bounce after HDR-BT combined with ERT is common and associated with a good prognosis. As the relapse risk after an early bounce is very low, the findings should alert clinicians not to initiate salvage treatment too early. Research in prospective identification of PSA bounce is clinically relevant.

    National Category
    Cancer and Oncology
    Identifiers
    urn:nbn:se:uu:diva-347416 (URN)
    Available from: 2018-03-31 Created: 2018-03-31 Last updated: 2018-05-08
  • Public defence: 2018-09-03 14:00 Ihresalen, Engelska parken, Uppsala
    Linderborg, Otto H.
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Languages, Department of Linguistics and Philology.
    Herodotus and the Origins of Political Philosophy: The Beginnings of Western Thought from the Viewpoint of its Impending End2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This investigation proposes a historical theory of the origins of political philosophy. It is assumed that political philosophy was made possible by a new form of political thinking commencing with the inauguration of the first direct democracies in Ancient Greece. The pristine turn from elite rule to rule of the people – or to δημοκρατία, a term coined after the event – brought with it the first ever political theory, wherein fundamentally different societal orders, or different principles of societal rule, could be argumentatively compared. The inauguration of this alternative-envisioning “secular” political theory is equaled with the beginnings of classical political theory and explained as the outcome of the conjoining of a new form of constitutionalized political thought (cratistic thinking) and a new emphasis brought to the inner consistency of normative reasoning (‘internal critique’). The original form of political philosophy, Classical Political Philosophy, originated when a political thought launched, wherein non-divinely sanctioned visions of transcendence of the prevailing rule, as well as of the full range of alternatives disclosed by Classical Political Theory, first began to be envisioned. Each of the hypotheses forming the theory – the hypotheses concerning the Ancient Greek beginnings of a “secular”-autonomous political rationale, political theory and political philosophy – is weighed against central evidence provided by the Histories of Herodotus. The passages thus given new interpretations are the Deioces episode in Book I, the Constitutional Debate in Book III and Xerxes’ War Councils in Book VII. Aside from the Herodotean evidence, a range of other relevant Greek literary sources from the archaic and classical ages – e.g. passages from Homer, Hesiod, several pre-Socratic thinkers, Plato and Aristotle – are duly taken into consideration. Included is also a reading of the Mytilenean Debate of Thucydides’ Book III, which shows how the political thought of the classical democracies worked in practice. Finally, the placing of the historical theory against a background of contemporary relevance provides an alternative to all text-oriented approaches not reckoning with the possibility of reaching historically plausible knowledge of real-world events and processes.

  • Public defence: 2018-09-07 10:00 Zootissalen, Uppsala
    Kunce, Warren
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Sub-lethal Effects of Anthropogenic Contaminants on Aquatic Invertebrates2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Anthropogenic contaminants are considered to play a substantial role in the decline of freshwater invertebrate diversity. Sub-lethal effects of many of these contaminants on behaviour and life-history traits of aquatic invertebrates may contribute to their decline. As contaminants are rarely present in the environment alone, the effects of mixture exposures are highly relevant in assessing the risk these substances pose to the biota. This thesis focuses on sub-lethal effects of exposure to aquatic pollutants, separately and in combination, on fresh-water invertebrates. To investigate the single and combined effects of pesticides, larvae of the midge, Chironomus riparius were exposed to a 1 hour pulse of two neonicotinoids and two pyrethroids.  This short exposure to environmentally relevant concentrations of pesticides decreased the survival and delayed development in C. riparius.  The combination of neonicotinoids and pyrethroids did not produce synergistic effects; however, there was some indication of antagonism. Additionally, larvae of the damselfly, Coenagrion puella, were exposed for 14 hours to two environmentally relevant concentrations of pyrethroid pesticides, alone and in combination. Exposure to the pyrethroid, deltamethrin, reduced the larvae’s predatory ability. Combined exposure to both deltamethrin and esfenvalerate inhibited the Glutathione S-transferase detoxification pathway and may have additive toxic effects on the larvae’s predatory ability. Microplastics are increasingly gaining attention as an aquatic pollutant of major concern with respect to the toxicity of the microplastics themselves as well as their capacity to adsorb persistent organic pollutants like pesticides. To investigate the effects of microplastics and a pyrethroid, alone and in combination, C. riparius larvae were raised in sediment spiked with two sizes of polystyrene-based latex microbeads and an environmentally relevant concentration of esfenvalerate under normal and food-restricted conditions. Exposure to both sizes of microplastics and esfenvalerate lead to equally decreased emergence under food-restricted conditions. Additionally, exposure to esfenvalerate led to decreases in survival when food was scarce that did not occur when microplastics were co-present. Antishistamines are also an emerging aquatic contaminant of concern with very little known about their biological effects on aquatic wildlife. Antihistamines could potentially interfere with the histaminergic pathways and thus affect thermal tolerance and temperature preference in aquatic invertebrates. The freshwater snail, Planorbarius corneus, was exposed for 24 hours to the antihistamine, diphenhydramine. This exposure increased thermal tolerance and righting time, but did not affect temperature preference. The results of the investigation suggest that anthropogenic contaminates alone and/or in combination have sub-lethal effects on life history, behavior and physiology of aquatic invertebrates. Such sub-lethal effects have the potential to affect populations and community structure in the aquatic and terrestrial environment.

    List of papers
    1. Combination effects of pyrethroids and neonicotinoids on development and survival of Chironomus riparius
    Open this publication in new window or tab >>Combination effects of pyrethroids and neonicotinoids on development and survival of Chironomus riparius
    2015 (English)In: Ecotoxicology and Environmental Safety, ISSN 0147-6513, E-ISSN 1090-2414, Vol. 122, p. 426-431Article in journal (Refereed) Published
    Abstract [en]

    Standard ecotoxicological risk assessments are conducted on individual substances, however monitoring of streams in agricultural areas has shown that pesticides are rarely present alone. In fact, brief but intense pulse events such as storm water runoff and spray drift during application subject freshwater environments to complex mixtures of pesticides at high concentrations. This study investigates the potential risks to non-target aquatic organisms exposed to a brief but intense mixture of the neonicotinoid pesticides imidacloprid and thiacloprid and the pyrethroid pesticides deltamethrin and esfenvalerate, compared to single substance exposure. All four of these pesticides have been detected in surface waters at concentrations higher than benchmark values and both classes of pesticides are known to exert adverse effects on non-target aquatic organisms under single substance exposure scenarios. First instar midge larvae of the non-target aquatic organism, Chironomus riparius, were exposed to combinations of these four pesticides at 50% of their LC50 (96 h) values in a 1 h pulse. They were then reared to adulthood in uncontaminated conditions and assessed for survival, development time and fecundity. Our results show that the risk of disruption to survival and development of non-target aquatic organisms under this scenario is not negligible on account of the significant increases in mortality of C. riparius found in the majority of the pesticide exposures and the delays in development after pyrethroid exposure. While none of the deleterious effects appear to be amplified by combination of the pesticides, there is some evidence for antagonism. No effects on fecundity by any of the pesticide treatments were observed.

    Keywords
    Brief exposure, Aquatic invertebrate, Mixture toxicity, Pesticide, Midge
    National Category
    Ecology Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-268704 (URN)10.1016/j.ecoenv.2015.09.008 (DOI)000364263000053 ()26379201 (PubMedID)
    Available from: 2015-12-09 Created: 2015-12-09 Last updated: 2018-06-27Bibliographically approved
    2. Single and mixture impacts of two pyrethroids on damselfly predatory behavior and physiological biomarkers
    Open this publication in new window or tab >>Single and mixture impacts of two pyrethroids on damselfly predatory behavior and physiological biomarkers
    2017 (English)In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 190, p. 70-77Article in journal (Refereed) Published
    Abstract [en]

    Direct mortality due to toxicity of single pesticide exposure along a concentration gradient, while the most common, is only one important parameter for assessing the effects of pesticide contamination on aquatic ecosystems. Sub-lethal toxicity can induce changes in an organism's behavior and physiology that may have population -level ramifications and consequences for ecosystem health. Additionally, the simultaneous detection of multiple contaminants in monitored watersheds stresses the importance of gaining a greater understanding of the toxicities of combined exposures, particularly at low, environmentally relevant concentrations. Using larvae of the Azure Damselfly (Coenagrion paella), we conducted a combined exposure investigation of two widely-used pyrethroid insecticides presumed to share the same neurotoxic mechanism of action, and estimated their effect on predatory ability, mobility and three physiological biomarkers (Glutathione S-transferase; GST, respiratory electron transport system; ETS, and malondialdehyde; MDA). Deltamethrin exposure (0.065 mu g/L and 0.13 mu g/L) was found to reduce the predatory ability, but it did not affect the larvae's mobility. Esfenvalerate exposure (0.069 mu g/L and 0.13 mu g/L), on the other hand, induced no significant changes in predatory ability or mobility. The decrease in predatory ability after the combination exposure (0.067 mu g/L deltamethrin and 0.12 mu g/L. esfenvalerate) did not significantly differ from the impact of the single deltamethrin exposures. Glutathione-S-transferase was induced after single esfenvalerate exposure and the lower deltamethrin concentration exposure, but seemingly inhibited after exposure to the higher concentration of deltamethrin as well as the combination of both pyrethroids. Our data indicate that sub-lethal exposure to deltamethrin reduces predatory ability and suggest that sub-lethal combined exposure to deltamethrin and esfenvalerate inhibits the GST detoxification pathway. These effects can eventually result in a lower emergence of adults from contaminated ponds.

    Place, publisher, year, edition, pages
    Elsevier, 2017
    Keywords
    Pesticides, Combination exposure, behavior, Sub-lethal effects, Aquatic invertebrate, Biomarkers
    National Category
    Pharmacology and Toxicology Other Biological Topics
    Identifiers
    urn:nbn:se:uu:diva-335643 (URN)10.1016/j.aquatox.2017.06.025 (DOI)000408783600009 ()28692868 (PubMedID)
    Available from: 2017-12-08 Created: 2017-12-08 Last updated: 2018-06-27Bibliographically approved
    3. Combined effects of microplastics and a pyrethroid on the benthic invertebrate, Chironomus Riparius
    Open this publication in new window or tab >>Combined effects of microplastics and a pyrethroid on the benthic invertebrate, Chironomus Riparius
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    There is growing evidence of widespread contamination of freshwater ecoystems with microplastics, plastic polymers that are < 5 mm. While a wide variety of organisms have been reported to ingest microplastics, the biological effects of chronic microplastic ingestion are not well understood.  Microplastics can adsorb organic pollutants in aqueous environments which made lead to increased exposure to these chemicals if desorption occurs after ingestion. Alternatively, relatively clean microplastics may adsorb chemicals in the gut decreasing their bioavailability. This study investigates the effects of chronic sediment exposure to latex-based polystyrene microspheres alone and in combination with the pyrethroid pesticide, esfenvalerate, on the life-history traits of the benthic invertebrate, Chironomus riparius, under two scenarios: abundant food and limited food. We found that chronic sediment exposure to 1.0 and 10.0 µm latex-based polystyrene latex microspheres, a low concentration of esfenvalerate and a combination of the 1.0 µm microspheres and esfenvalerate led to no significant effects on survival, development time, emergence, or sex of C. riparius when food was abundant. However, effects of exposure did become apparent when food was insufficient indicating that these contaminants may be stressors with an energy cost to the organism.

    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-354695 (URN)
    Available from: 2018-06-21 Created: 2018-06-21 Last updated: 2018-06-27
    4. Effects of acute antihistamine exposure on thermal tolerance and behaviour in the freshwater snail, Planorbarius corneus
    Open this publication in new window or tab >>Effects of acute antihistamine exposure on thermal tolerance and behaviour in the freshwater snail, Planorbarius corneus
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Antihistamine pollutants have the potential to interfere with the normal functioning of aquatic organisms due to their intentionally bio-active nature. Histamine is a neurotransmitter present in multiple tissues in both vertebrates and invertebrates and histaminergic pathways have been identified in the thermoregulatory processes of invertebrates. Disruption of normal histamine functioning via exposure to the widespread antihistamine pollution observed in fresh waters may induce a range of sub-lethal effects on aquatic invertebrates including thermoregulatory and behavioural changes. We conducted three experiments exposing freshwater snails (Planorbarius corneus) to the antihistamine, diphenhydramine, for 24 hours then evaluating thermal tolerance, temperature preference and righting time. Diphenhydramine was found to increase thermal tolerance and righting time, but did not affect temperature preference. These results warrant further investigation into the biological effects of antihistamines on aquatic wildlife as well as altered thermal tolerance and thermoregulation as relevant toxicological endpoints in ecotoxicological risk assessment of pharmaceuticals.

    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-354696 (URN)
    Available from: 2018-06-21 Created: 2018-06-21 Last updated: 2018-06-27
  • Public defence: 2018-09-07 10:15 Häggsalen, Uppsala
    Zhang, Teng
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Synchrotron Radiation Studies of Molecular Building Blocks for Functional Materials2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The research on new materials is a primary driving force for progress in human society. One of the most significant research topic nowadays is the development of new functional materials for technological applications, like perovskite implemented in solar cells, and graphene as a representative for the new 2D materials family. It is then crucial to fully understand the functionality of such materials from a fundamental point of view, as a complementary and useful guide to develop/design new devices of improved performance and energy efficiency.

    In the thesis, comprehensive characterizations of molecular building blocks used in i) novel energy conversion devices (CoPc, TPA, DPTA and m-MTDATA), and ii) in 2D materials (biphenylene and melamine) have been performed by PhotoElectron Spectroscopy (PES), and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy carried out at synchrotron radiation facilities, representing effective, powerful light source dedicated to the front-line materials research of great value in both science and industry. PES and NEXAFS spectroscopy, in combination with Density Functional Theory (DFT) calculations have provided a deep understanding of the electronic structure of the investigated systems in relation to their functionality. The investigations always included the combination and comparison between experimental and theoretical results. The studied molecules were characterized as free and adsorbed on surfaces, from the simple building blocks to more complex molecular systems. The characterizations allowed us to identify the electronic structure modifications due to substitutions (Paper III), increasing complexity of the molecules (Paper V), molecule-substrate interactions (Paper I, II, IV, V) and intra-molecular H-bonding interactions (Paper VI).

    List of papers
    1. Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study
    Open this publication in new window or tab >>Conclusively Addressing the CoPc Electronic Structure: A Joint Gas-Phase and Solid-State Photoemission and Absorption Spectroscopy Study
    Show others...
    2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 47, p. 26372-26378Article in journal (Refereed) Published
    Abstract [en]

    The occupied and empty densities of states of cobalt phthalocyanine (CoPc) were investigated by photoelectron and X-ray absorption spectroscopies in the gas phase and in thin films deposited on a Au(111) surface. The comparison between the gas-phase results and density functional theory single-molecule simulations confirmed that the CoPc ground state is correctly described by the (2)A(1g) electronic configuration. Moreover, photon-energy-dependent valence photoemission spectra of both the gas phase and thin film confirmed the atomic character of the highest occupied molecular orbital as being derived from the organic ligand, with dominant contributions from the carbon atoms. Multiplet ligand-field theory was employed to simulate the Co L-edge X-ray absorption spectroscopy results.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 2017
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:uu:diva-344315 (URN)10.1021/acs.jpcc.7b08524 (DOI)000417228500026 ()
    Funder
    Swedish Research CouncilCarl Tryggers foundation
    Available from: 2018-03-08 Created: 2018-03-08 Last updated: 2018-06-29Bibliographically approved
    2. Electronic structure investigations of biphenylene films
    Open this publication in new window or tab >>Electronic structure investigations of biphenylene films
    Show others...
    (English)Article in journal (Refereed) Submitted
    Abstract [en]

    Photoelectron Spectroscopy (PES) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy have been used to investigate the occupied and empty density of states of biphenylene films of different thicknesses, deposited onto a Cu(111) crystal. The obtained results have been compared to previous gas phase spectra and single molecule density functional theory (DFT) calculations to get insights into the possible modification of the molecular electronic structure in the film induced by the adsorption on a surface. Furthermore, NEXAFS measurements allowed characterizing the variation of the molecular arrangement with the film thickness and helped to clarify the substrate- molecule interaction. 

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-307784 (URN)
    Available from: 2016-11-21 Created: 2016-11-21 Last updated: 2018-06-29
    3. Lone Pair Delocalization Effect within Electron Donor Molecules: The Case of Triphenylamine (TPA) and Its Thiophene-Analog (DPTA)
    Open this publication in new window or tab >>Lone Pair Delocalization Effect within Electron Donor Molecules: The Case of Triphenylamine (TPA) and Its Thiophene-Analog (DPTA)
    Show others...
    (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455Article in journal (Refereed) Submitted
    Abstract [en]

    Triphenylamine (TPA) and its thiophene-analog, N,N-Diphenyl-2-thiophenamine (DPTA), are both well known as electron-donating molecules implemented in optoelectronic devices such as organic solar cells and LEDs. Comprehensive valence and core level PhotoElectron Spectroscopy (PES), as well as Near Edge X-ray Absorption Spectroscopy (NEXAFS) measurements have been performed on gas-phase TPA and DPTA. The experimental results have been compared to Density Functional Theory (DFT) calculations, providing a detailed description of the molecular electronic structure. Specifically, the C 1s photoelectron lines of both TPA and DPTA were resolved in the different C atom contributions and their binding energies explained as the result of two counter-acting effects: (1) the electronegativity of the nitrogen atom (and sulphur atom in DPTA) and (2) the delocalization of the N (and S in DPTA) lone pair electrons. In addition, the C K-edge NEXAFS spectrum of DPTA reveals that the Lowest Unoccupied Molecular Orbital (LUMO) energy position is affected differently if the core-hole site is on the phenyl compared to the thiophene ring. The electron-donating properties of these two molecules are largely explained by the significant contribution of the N lone pair electrons (pz) to the Highest Occupied Molecular Orbital (HOMO). The contribution to the LUMO and to the empty density of states of the sulphur of the thiophene ring in DPTA explains the better performance of Donor-π-Acceptor molecules containing this moiety and implemented in photo-energy conversion devices.

    National Category
    Physical Sciences
    Research subject
    Physics with spec. in Atomic, Molecular and Condensed Matter Physics
    Identifiers
    urn:nbn:se:uu:diva-355118 (URN)
    Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29
    4. X-ray Spectroscopy Investigations of TPA/Au(111): Charge Redistribution via Core Exitation?
    Open this publication in new window or tab >>X-ray Spectroscopy Investigations of TPA/Au(111): Charge Redistribution via Core Exitation?
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Triphenylamine (TPA) is a well-known electron donor molecule largely used in photovoltaics. In this article we analyze the electronic structure modifications due to the adsorption of the molecules at a monolayer coverage on a Au(111) surface. Only a weak interaction was observed between the TPA and the gold during the adsorption process, being impossible to get more than 1ML coverage at room temperature. The characterizations have been performed by core and valence Photoelectron Spectroscopy (PES) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The results were compared with our previous investigations on free TPA, and theoretical models were used to explain the changes of the electronic structure due to the adsorption on the metallic gold surface. The calculation confirms the weak interaction between the adsorbed TPA and the Au(111), with only a slight change of the twisting angle of the TPA phenyl rings. The resulting adsorption geometry can be used to explain the broadening of the C 1s PES line with respect to the gas-phase results and the expected absence of angle dependence in the C K-edge NEXAFS. However, a significant modification was observed in the N K-edge NEXAFS spectra of TPA/Au(111), showing a new pre-edge feature due to transitions involving out-of-plane orbitals. This pre-edge feature is ascribed to the interaction between the molecules and the surface, having a different character and energy position than the pre-edge observed for free TPA. A model, considering a TPA+ cation formed by a charge redistribution process between the adsorbate and the surface valence states seems to give a qualitative explanation of this pre-edge intensity. Since our calculations predict only a weak interaction between the TPA molecules and the gold surface, we propose that such a charge redistribution happens in the core-excited state created by photon absorption.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-355120 (URN)
    Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29
    5. Electronic Structure Study of Free and Adsorbed m-MTDATA
    Open this publication in new window or tab >>Electronic Structure Study of Free and Adsorbed m-MTDATA
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The starburst p-conjugated molecule based on triphenylamine (TPA) building block, 4,4',4" -Tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (m-MTDATA), is widely used in optoelectronic devices due to its electron-donating properties. The electronic structure of m-MTDATA was investigated in the gas-phase and when deposited in thin films on a Au(111) surface by means of PhotoElectron Spectroscopy (PES) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. Density Functional Theory (DFT) calculations were compared to the experimental gas-phase results, providing a comprehensive description of the molecular electronic structure. Moreover, the results were compared with previous TPA measurements, shedding light on the electronic structure modification due to the increased molecular complexity.  Similar to TPA, but more complex, the binding energy of the C 1s photoelectron line of m-MTDATA results from the balance of two counter-acting effects: (1) the electronegativity of the N atoms and (2) the delocalization of lone-pair electrons of the nitrogen. Compared to TPA, the outermost valence PE spectrum of m-MTDATA shows a 3-peak feature with N 2pz character and a lowering of the binding energy of the HOMO. When adsorbed on Au(111),  the changes observed in PES and NEXAFS spectra with respect to the free molecules,  can be explained by a significant modification of m-MTDATA molecular and electronic structure, due to the molecule-substrate interaction.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-355121 (URN)
    Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29
    6. Spectroscopic Fingerprints of Carbon Nitride Functional Groups Locked-up in Intermolecular H-bonding Interactions
    Open this publication in new window or tab >>Spectroscopic Fingerprints of Carbon Nitride Functional Groups Locked-up in Intermolecular H-bonding Interactions
    Show others...
    (English)In: Chemistry: A European Journal, ISSN 0947-6539Article in journal (Refereed) Submitted
    Abstract [en]

    We have investigated the effect of intermolecular H- bonding interactions on the local electronic structure of N- functionalities, amino group and pyridine-like N, which are characteristic of a new class of metal-free polymeric photo-catalysts named graphitic carbon nitrides, g-C3N4. Specifically, we have performed a characterization of the melamine molecule, a building block of g-C3N4, combining X-ray photoemission (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The molecule has been studied in the gas phase, as non-interacting system, and in the solid state within a hydrogen bonded network. With the support of density functional theory (DFT) simulations of the spectra, we have found that the H-bonds mainly affect the N 1s level of the amino group, leaving the N 1s level of the pyridine-like N mostly unperturbed. This fact is responsible for a reduction of the chemical shift between the two XPS N 1s levels, compared to the free melamine. Consequently, N K-edge NEXAFS resonances involving the amino N 1s level also shift to lower photon energies. Moreover, the solid state absorption spectra have shown strong modification/quenching of resonances related with transitions from the amino N 1s level towards σ*orbitals involving the -NH2 terminations. 

    National Category
    Physical Sciences
    Research subject
    Physics with spec. in Atomic, Molecular and Condensed Matter Physics
    Identifiers
    urn:nbn:se:uu:diva-355123 (URN)
    Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29
  • Public defence: 2018-09-07 13:15 Polhemsalen, Uppsala
    Zimmermann, Jakob
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics, Algebra and Geometry.
    Classification of simple transitive 2-representations2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The representation theory of finitary 2-categories is a generalization of the classical representation theory of finite dimensional associative algebras. A key notion in classical representation theory is the notion of simple modules as those are in some sense the building blocks of all modules. A correct analogue of simple modules in the realm of 2-representations is the notion of simple transitive 2-representations since those also turn out to be building blocks of 2-representations.

    This thesis is concerned with the classification of simple transitive 2-representations for a number of different interesting 2-categories. In Paper I we study simple transitive 2-representations of Soergel bimodules in Coxeter type I2(4) and show that all simple transitive 2-representations in this case are equivalent to cell 2-representations. In Paper II we classify simple transitive 2-representations for the quotient of the 2-category of Soergel bimodules over the coinvariant algebra which is associated to the two-sided cell that is the closest to the two-sided cell containing the identity element, in all Coxeter types but I2(12), I2(18) and I2(30). It turns out that, in most of the cases, simple transitive 2-representations are exhausted by cell 2-representations. However, in Coxeter types I2(2k), where k ≥ 3, there exist simple transitive 2-representations which are not equivalent to cell 2-representations. In Paper III we show that for any complex polynomial p(X) the set of irreducible, integer matrices which are annihilated by p(X) is finite. Moreover, we study the set of irreducible, integral matrices satisfying X² = nX, for n ≥ 1, and count its elements. In Paper IV we show that every simple transitive 2-representations of the 2-category of projective functors for a certain quotient of the quadratic dual of the preprojective algebra associated with a tree is equivalent to a cell 2-representation. Finally, in Paper V we study simple transitive 2-representations of certain 2-subcategories of the 2-categories of projective functors over star algebras. In the simplest case, which is associated with Dynkin type A2, we show that simple transitive 2-representations are classified by cell 2-representations. However, in the general case we conjecture that there exist many more simple transitive 2-representations.

    List of papers
    1. Simple transitive 2-representations of left cell 2-subcategories of projective functors for star algebras
    Open this publication in new window or tab >>Simple transitive 2-representations of left cell 2-subcategories of projective functors for star algebras
    (English)In: Communications in Algebra, ISSN 0092-7872, E-ISSN 1532-4125Article in journal (Refereed) Submitted
    Abstract [en]

    In this paper we study simple transitive 2-representations of certain 2-subcategories of the 2-category of projective functors over a star algebra. We show that in the simplest case, which is associated to the Dynkin type A2, simple transitive 2-representations are classified by cell 2-representations. In the general case we conjecture that there exist many simple transitive 2-representations which are not cell 2-representations and provide some evidence for our conjecture.

    National Category
    Mathematics
    Identifiers
    urn:nbn:se:uu:diva-354589 (URN)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
    2. Simple transitive 2-representations of Soergel bimodules in type B2
    Open this publication in new window or tab >>Simple transitive 2-representations of Soergel bimodules in type B2
    2017 (English)In: Journal of Pure and Applied Algebra, ISSN 0022-4049, E-ISSN 1873-1376, Vol. 221, no 3, p. 666-690Article in journal (Refereed) Published
    Abstract [en]

    We prove that every simple transitive 2-representation of the fiat 2-category of Soergel bimodules (over the coinvariant algebra) in type B2 is equivalent to a cell 2-representation. We also describe some general properties of the 2-category of Soergel bimodules for arbitrary finite dihedral groups.

    National Category
    Mathematics
    Identifiers
    urn:nbn:se:uu:diva-354583 (URN)10.1016/j.jpaa.2016.07.011 (DOI)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
    3. Simple transitive 2-representations of some 2-categories of projective functors
    Open this publication in new window or tab >>Simple transitive 2-representations of some 2-categories of projective functors
    2018 (English)In: Beiträge zur Algebra und Geometrie, ISSN 0138-4821, Vol. 59, no 1, p. 41-50Article in journal (Refereed) Published
    Abstract [en]

    We show that every simple transitive 2-representation of the $2$-category of projective functors for a certain quotient of the quadratic dual of the preprojective algebra associated with a tree is equivalent to a cell 2-representation.

    Place, publisher, year, edition, pages
    Berlin/Heidelberg: Springer Berlin/Heidelberg, 2018
    Keywords
    Representation theory, 2-category, Simple transitive 2-representation, Cell 2-representation
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:uu:diva-354581 (URN)10.1007/s13366-017-0348-4 (DOI)000431552200004 ()
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-07-04Bibliographically approved
    4. Simple transitive 2-representations of small quotients of Soergel bimodules
    Open this publication in new window or tab >>Simple transitive 2-representations of small quotients of Soergel bimodules
    (English)In: Transactions of the American Mathematical Society, ISSN 0002-9947, E-ISSN 1088-6850Article in journal (Refereed) Accepted
    Abstract [en]

    In all finite Coxeter types but I2(12), I2(18) and I2(30), we classify simple transitive 2-representations for the quotient of the 2-category of Soergel bimodules over the coinvariant algebra which is associated to the two-sided cell that is the closest one to the two-sided cell  containing the identity element. It turns out that, in most of the cases, simple transitive 2-representations are exhausted by cell 2-representations. However, in Coxeter types I2(2k), where k ≥ 3, there exist simple transitive 2-representations which are not equivalent to cell 2-representations.

    National Category
    Mathematics
    Identifiers
    urn:nbn:se:uu:diva-354594 (URN)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
    5. Counting Quasi-idempotent Irreducible Integral Matrices
    Open this publication in new window or tab >>Counting Quasi-idempotent Irreducible Integral Matrices
    2018 (English)In: Journal of Integer Sequences, ISSN 1530-7638, E-ISSN 1530-7638, Vol. 21, no 4, article id 18.4.48Article in journal (Refereed) Published
    Abstract [en]

    Given any polynomial p in C[X], we show that the set of irreducible matrices satisfying p(A)=0 is finite. In the specific case p(X)=X2-nX, we count the number of irreducible matrices in this set and analyze the arising sequences and their asymptotics. Such matrices turn out to be related to generalized compositions and generalized partitions.

    National Category
    Mathematics
    Identifiers
    urn:nbn:se:uu:diva-354586 (URN)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
  • Public defence: 2018-09-07 13:25 Häggsalen, Uppsala
    Yang, Jiaojiao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Amorphous magnesium carbonate nanomaterials: Synthesis, characterization and applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    High surface-to-volume ratio materials, including nanoparticles and mesoporous materials, have a number of applications due to their large surface area and special structures. Traditional approaches for synthesizing high surface-to-volume ratio nanomaterials are often complicated, expensive or environmentally unfriendly. Considering aspects such as availability and safety in terms of environmental or biological contact, magnesium carbonate-based nanomaterials are an interesting and potentially valuable candidate for novel applications. The overall aim of this thesis was to develop novel high surface-to-volume ratio amorphous magnesium carbonate nanomaterials and investigating their possible applications.

    Amorphous magnesium carbonate nanoparticles (AMN) were successfully synthesized via a simple and low-temperature pathway. The structure and resulting properties of the material can be tailored by changing the final steps in the synthesis process.

    The ability of AMN to stabilize ibuprofen (IBU) in the amorphous state was investigated. Nanocomposites with IBU:AMN mass ratios as high as to 5:1 were shown to enhance the release rate of IBU in vitro by as much as 83 times compared to IBU in crystalline form. A related nanostructured material, mesoporous magnesium carbonate (MMC), was evaluated as a drug carrier for stabilizing amorphous drugs through the incorporation of the drug within its pores. In this study, MMC was used to release and sustain two poorly soluble drugs (tolfenamic acid and rimonabant) in the supersaturated state with the assistance of hydroxypropyl methylcellulose.

    AMN was also used to synthesize a novel adhesive together with IBU without the addition of a polymer. This adhesive was transparent, self-healing, shapeable, stretchable and reusable. In addition, the adhesive was able to glue a variety of materials, including metals, glass, paper and plastics (even Teflon).

    Finally, AMN was used to prepare flexible, transparent and UV-shielding films when incorporated into a PMMA matrix. These films exhibited both UV-shielding properties and moisture absorbance and retention abilities. In addition, the UV- and thermo-stability of these films were enhanced by the addition of AMN.

    The work presented in this thesis show that the nanomaterials AMN and MMC possess great potential for an extremely broad range of applications, from pharmaceutical applications dealing with poorly soluble drugs to structural applications such as adhesives to applications in optics or electronics such as UV-shielding or moisture barrier films.

    List of papers
    1. Synthesis and Characterization of Amorphous Magnesium Carbonate Nanoparticles
    Open this publication in new window or tab >>Synthesis and Characterization of Amorphous Magnesium Carbonate Nanoparticles
    Show others...
    (English)In: Article in journal (Refereed) Submitted
    National Category
    Nano Technology
    Identifiers
    urn:nbn:se:uu:diva-354505 (URN)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
    2. Amorphous Magnesium Carbonate Nanoparticles with Strong Stabilizing Capability for Amorphous Ibuprofen
    Open this publication in new window or tab >>Amorphous Magnesium Carbonate Nanoparticles with Strong Stabilizing Capability for Amorphous Ibuprofen
    Show others...
    (English)In: Article in journal (Refereed) Submitted
    National Category
    Nano Technology
    Identifiers
    urn:nbn:se:uu:diva-354506 (URN)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
    3. Enhanced UV protection and water adsorption properties of transparent poly(methyl methacrylate) films through incorporation of amorphous magnesium carbonate nanoparticles
    Open this publication in new window or tab >>Enhanced UV protection and water adsorption properties of transparent poly(methyl methacrylate) films through incorporation of amorphous magnesium carbonate nanoparticles
    (English)Manuscript (preprint) (Other academic)
    National Category
    Nano Technology
    Identifiers
    urn:nbn:se:uu:diva-354510 (URN)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
    4. Adhesives from Inorganic Nanoparticles and Low-Molecular-Weight Organic Compounds
    Open this publication in new window or tab >>Adhesives from Inorganic Nanoparticles and Low-Molecular-Weight Organic Compounds
    Show others...
    (English)Manuscript (preprint) (Other academic)
    National Category
    Nano Technology
    Identifiers
    urn:nbn:se:uu:diva-354509 (URN)
    Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-06-20
    5. Enhanced release of poorly water-soluble drugs from synergy between mesoporous magnesium carbonate and polymers
    Open this publication in new window or tab >>Enhanced release of poorly water-soluble drugs from synergy between mesoporous magnesium carbonate and polymers
    Show others...
    2017 (English)In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 525, no 1, p. 183-190Article in journal (Refereed) Published
    Abstract [en]

    Abstract The need to combat poor water solubility has increased interest in supersaturating drug delivery systems. In this study, amorphous mesoporous magnesium carbonate (MMC) was used as a drug carrier to achieve supersaturation of tolfenamic acid and rimonabant, two drug compounds with low aqueous solubility. The potential synergy between MMC and hydroxypropyl methylcellulose (HPMC), a polymer commonly included as a precipitation inhibitor in drug delivery systems, was explored with the aim of extending the time that high supersaturation levels were maintained. Release was studied under physiological conditions using USP-2 dissolution baths. A new small-scale method was developed to enable measurement of the initial drug release occurring when the MMC is immersed in the water phase. It was shown that MMC and HPMC together resulted in significant supersaturation and that the polymer enabled both the achievement of a higher API concentration and extension of the supersaturation period. The new small-scale release method showed that the release was linearly increasing with the dose and that similar release rates were observed for the two model compounds. It was hence concluded that the MMC release was diffusion limited for the compounds explored.

    Keywords
    Magnesium carbonate, Mesoporous, Hydroxypropyl methylcellulose, Tolfenamic acid, Rimonabant, Supersaturation
    National Category
    Nano Technology
    Research subject
    Engineering Science with specialization in Nanotechnology and Functional Materials
    Identifiers
    urn:nbn:se:uu:diva-320987 (URN)
    Available from: 2017-04-27 Created: 2017-04-27 Last updated: 2018-06-20
  • Public defence: 2018-09-08 09:00 Room 22-0008, Uppsala
    Basirat, Ali
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Languages, Department of Linguistics and Philology.
    Principal Word Vectors2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Word embedding is a technique for associating the words of a language with real-valued vectors, enabling us to use algebraic methods to reason about their semantic and grammatical properties. This thesis introduces a word embedding method called principal word embedding, which makes use of principal component analysis (PCA) to train a set of word embeddings for words of a language. The principal word embedding method involves performing a PCA on a data matrix whose elements are the frequency of seeing words in different contexts. We address two challenges that arise in the application of PCA to create word embeddings. The first challenge is related to the size of the data matrix on which PCA is performed and affects the efficiency of the word embedding method. The data matrix is usually a large matrix that requires a very large amount of memory and CPU time to be processed. The second challenge is related to the distribution of word frequencies in the data matrix and affects the quality of the word embeddings. We provide an extensive study of the distribution of the elements of the data matrix and show that it is unsuitable for PCA in its unmodified form.

    We overcome the two challenges in principal word embedding by using a generalized PCA method. The problem with the size of the data matrix is mitigated by a randomized singular value decomposition (SVD) procedure, which improves the performance of PCA on the data matrix. The data distribution is reshaped by an adaptive transformation function, which makes it more suitable for PCA. These techniques, together with a weighting mechanism that generalizes many different weighting and transformation approaches used in literature, enable the principal word embedding to train high quality word embeddings in an efficient way.

    We also provide a study on how principal word embedding is connected to other word embedding methods. We compare it to a number of word embedding methods and study how the two challenges in principal word embedding are addressed in those methods. We show that the other word embedding methods are closely related to principal word embedding and, in many instances, they can be seen as special cases of it.

    The principal word embeddings are evaluated in both intrinsic and extrinsic ways. The intrinsic evaluations are directed towards the study of the distribution of word vectors. The extrinsic evaluations measure the contribution of principal word embeddings to some standard NLP tasks. The experimental results confirm that the newly proposed features of principal word embedding (i.e., the randomized SVD algorithm, the adaptive transformation function, and the weighting mechanism) are beneficial to the method and lead to significant improvements in the results. A comparison between principal word embedding and other popular word embedding methods shows that, in many instances, the proposed method is able to generate word embeddings that are better than or as good as other word embeddings while being faster than several popular word embedding methods.

  • Public defence: 2018-09-12 10:15 E22, Visby
    Simisiroglou, Nikolaos
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Wind power wake modelling: Development and application of an actuator disc method for industrial utilization.2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    As a wind turbine extracts energy from the wind it creates a region downstream where the wind velocity is decreased and the urbulence intensity is increased, this region is commonly called the wake region. Today’s wind farms include a large number of wind turbines position in tight layouts. These tight layouts result in increased power losses due to wakes, rendering accurate wind turbine wake modelling crucial in developing cost effective projects.

    The primary aim of this study is to create a method capable of conducting full-scale wind farm wake computations accurately in a time efficient manner by taking into account the computational resources and data availability of a typical industrial user. As a first step of this study, an actuator disc (ACD) method (old ACD) used within WindSim, is evaluated against power production data from the Lillgrund offshore wind. This study is followed by the development of a new ACD method. The new ACD method differs from the previous ACD method in terms of how the thrust distribution and the power production is calculated. A series of validation studies are performed on this newly introduced ACD method. These consist of validating the method against two cases with known analytical solutions, the research code EllipSys3D which uses Large Eddy Simulation (LES) based computations with an ACD approach and three differentwind tunnel set–ups. Lastly, a comparative analysis of the two ACD methods (old and new) and two analytical wake models is done using wind turbine power production data from Lillgrund.

    Results from the validation studies show that this new ACD method is able to predict the overall behaviour of the flow with low computational effort while also taking into account the availability of data for a typical industrial user. One may say that the new ACD method in RANS, which has much lower computational requirements than the ACD method in LES at the cost of lower accuracy, represents a good compromise. Lastly, the results from the new ACD method show a clear improvement in the estimated power production for the Lillgrund wind farm in comparison to the old ACD method.

    List of papers
    1. Numerical CFD comparison of Lillgrund employing RANS EERA
    Open this publication in new window or tab >>Numerical CFD comparison of Lillgrund employing RANS EERA
    Show others...
    2014 (English)Conference paper, Oral presentation only (Refereed)
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-238295 (URN)
    Conference
    DeepWind 2014, 11th Deep Sea Offshore Wind R&D Conference
    Funder
    StandUp for Wind
    Available from: 2014-12-11 Created: 2014-12-11 Last updated: 2018-05-03
    2. Description and validation of the actuator disc approach in PHOENICS.
    Open this publication in new window or tab >>Description and validation of the actuator disc approach in PHOENICS.
    2016 (English)Report (Other (popular science, discussion, etc.))
    National Category
    Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-350027 (URN)
    Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-05-03
    3. Validation of the actuator disc approach using small-scale model wind turbines
    Open this publication in new window or tab >>Validation of the actuator disc approach using small-scale model wind turbines
    2017 (English)In: Wind Energy Science, ISSN 2213-3968, E-ISSN 2366-7443, Vol. 2, p. 587-601Article in journal (Refereed) Published
    Abstract [en]

    The aim of the present study is the validation of the implementation of an actuator disc (ACD) model in the computational fluid dynamics (CFD) code PHOENICS. The flow behaviour for three wind turbine cases is investigated numerically and compared to wind tunnel measurements: (A) the flow around a single model wind turbine, (B) the wake interaction between two in-line model wind turbines for a uniform inflow of low turbulence intensity and (C) the wake interaction between two in-line model wind turbines at different separation distances in a uniform or sheared inflow of high turbulence intensity. This is carried out using Reynolds-averaged Navier–Stokes (RANS) simulations and an ACD technique in the CFD code PHOENICS. The computations are conducted for the design condition of the rotors using four different turbulence closure models and five different thrust distributions. The computed axial velocity field as well as the turbulence kinetic energy are compared with hot-wire anemometry (HWA) measurements. For the cases with two in-line wind turbines, the thrust coefficient is also computed and compared with measurements. The results show that for different inflow conditions and wind turbine spacings the proposed method is able to predict the overall behaviour of the flow with low computational effort. When using the k-ε and Kato–Launder k-ε turbulence models the results are generally in closer agreement with the measurements.

    National Category
    Fluid Mechanics and Acoustics
    Identifiers
    urn:nbn:se:uu:diva-338124 (URN)10.5194/wes-2-587-2017 (DOI)000416160500001 ()
    Available from: 2018-01-08 Created: 2018-01-08 Last updated: 2018-05-03Bibliographically approved
    4. The actuator disc concept in PHOENICS
    Open this publication in new window or tab >>The actuator disc concept in PHOENICS
    Show others...
    2016 (English)In: Energy Procedia / [ed] Tande, JOG; Kvamsdal, T; Muskulus, M, 2016, Vol. 94, p. 269-277Conference paper, Published paper (Refereed)
    Abstract [en]

    This study presents two models to simulate a wind turbine. This is done by employing the 1D momentum actuator disc theory in PHOENICS, a general purpose computational fluid dynamics software. To test the general applicability of these models, single wind turbine simulations are conducted using eight different wind turbine models from two manufacturers. The simulations are performed by imposing sheared inflow with hub height wind speeds ranging from 3 m/s up to 25 m/s. A range of computational parameters are investigated, including the resolution of the domain, the thickness of the actuator disc and the iterative convergence criteria. To investigate the wake development produced by these methods, a comparison study is performed with the more complex large-eddy simulation software EllipSys3D using an actuator disc approach for validation purposes. The resulting wind turbine thrust and power outputs from PHOENICS are compared with the experimental power curves and thrust values provided by the manufacturers for each wind turbine. The results show that actuator disc methods are able to provide a reasonable estimation of the conventional wind turbine power and thrust output with low computational effort. Moreover, the results from the preliminary comparison of the wake produced from these two rotor models compare well with the wake produced by the actuator disc in EllipSys3D.

    Series
    Energy Procedia, ISSN 1876-6102 ; 94
    Keywords
    Wind energy, Computational Fluid Dynamics (CFD), Reynolds averaged Navier-Stokes (RANS), Actuator Disc (ACD), Large-eddy simulation (LES)
    National Category
    Earth and Related Environmental Sciences Environmental Engineering
    Identifiers
    urn:nbn:se:uu:diva-306640 (URN)10.1016/j.egypro.2016.09.182 (DOI)000387586600028 ()
    Conference
    13th Deep Sea Offshore Wind R&D Conference, EERA DeepWind’ JAN 20-22, 2016, Trondheim, Norway
    Funder
    StandUp for Wind
    Available from: 2016-10-31 Created: 2016-10-31 Last updated: 2018-05-03Bibliographically approved
    5. Wind farm power production assessment: a comparative analysis of two actuator disc methods and two analytical wake models
    Open this publication in new window or tab >>Wind farm power production assessment: a comparative analysis of two actuator disc methods and two analytical wake models
    2018 (English)In: Wind Energy Science, ISSN 2213-3968, E-ISSN 2366-7443, Vol. 2018, p. 1-13Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    The aim of the present study is to perform a comparative analysis of two actuator disc methods (ACD) and two analytical wake models for wind farm power production assessment. To do so wind turbine power production data from the Lillgrund offshore wind farm in Sweden is used. The measured power production for individual wind turbines is compared with results from simulations, done in the WindSim software, using two ACD methods (old and new) and two analytical wake models widely used within the wind industry (Jensen and Larsen wake models). It was found that the new ACD method and the Larsen model outperform the other method and model in most cases. Furthermore, results from the new ACD method show a clear improvement in the estimated power production in comparison to the old ACD method. The Jensen method seems to overestimate the power deficit for all cases. The new ACD method, despite it's simplicity, is capable of capturing the power production within the given error margin although it tends to underestimate the power deficit.

    National Category
    Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-350026 (URN)10.5194/wes-2018-8 (DOI)
    Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-05-07Bibliographically approved
    6. Validation of the actuator disc approach inPHOENICS using small scale model wind turbines
    Open this publication in new window or tab >>Validation of the actuator disc approach inPHOENICS using small scale model wind turbines
    2016 (English)In: Journal of Physics: Conference Series, 2016, Vol. 753, p. 032-028Conference paper, Published paper (Refereed)
    Abstract [en]

    In this study two wind turbine setups are investigated numerically: (a) the flow around a single model wind turbine and (b) the wake interaction between two in-line model wind turbines. This is done by using Reynolds averaged Navier-Stokes (RANS) and an actuator disc (ACD) technique in the computational fluid dynamics code PHOENICS. The computations are conducted for the design condition of the rotors using four different turbulence closure models. The computed axial velocity field as well as the turbulent kinetic energy are compared with PIV measurements. For the two model wind turbine setup, the thrust and power coefficient are also computed and compared with measurements. The results show that this RANS ACD method is able to predict the overall behaviour of the flow with low computational effort and that the turbulence closure model has a direct effect on the predicted wake development.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-306642 (URN)10.1088/1742-6596/753/3/032028 (DOI)
    Conference
    Science of Making Torque from Wind
    Funder
    StandUp for Wind
    Available from: 2016-10-31 Created: 2016-10-31 Last updated: 2018-05-03