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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- van Cappellen, W., et al.
(författare)
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Apertif: Phased array feeds for the Westerbork Synthesis Radio Telescope: System overview and performance characteristics
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 658
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Tidskriftsartikel (refereegranskat)abstract
- We describe the APERture Tile In Focus (Apertif) system, a phased array feed (PAF) upgrade of the Westerbork Synthesis Radio Telescope that transforms this telescope into a high-sensitivity, wide-field-of-view L-band imaging and transient survey instrument. Using novel PAF technology, up to 40 partially overlapping beams are formed on the sky simultaneously, significantly increasing the survey speed of the telescope. With this upgraded instrument, an imaging survey covering an area of 2300 deg2 is being performed that will deliver both continuum and spectral line datasets, of which the first data have been publicly released. In addition, a time domain transient and pulsar survey covering 15 000 deg2 is in progress. An overview of the Apertif science drivers, hardware, and software of the upgraded telescope is presented, along with its key performance characteristics.
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| 9. |
- Rottgering, H., et al.
(författare)
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LOFAR and APERTIF Surveys of the Radio Sky: Probing Shocks and Magnetic Fields in Galaxy Clusters
- 2011
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Ingår i: Journal of Astrophysics and Astronomy. - : Springer Science and Business Media LLC. - 0250-6335 .- 0973-7758. ; 32:4, s. 557-566
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Tidskriftsartikel (refereegranskat)abstract
- At very low frequencies, the new pan-European radio telescope LOFAR is opening the last unexplored window of the electromagnetic spectrum for astrophysical studies. The revolutionary APERTIF-phased arrays that are about to be installed on the Westerbork radio telescope (WSRT) will dramatically increase the survey speed for the WSRT. Combined surveys with these two facilities will deeply chart the northern sky over almost two decades in radio frequency from similar to 15 up to 1400 MHz. Here we briefly describe some of the capabilities of these new facilities and what radio surveys are planned to study fun-damental issues related to the formation and evolution of galaxies and clusters of galaxies. In the second part we briefly review some recent observational results directly showing that diffuse radio emission in clusters traces shocks due to cluster mergers. As these diffuse radio sources are relatively bright at low frequencies, LOFAR should be able to detect thousands of such sources up to the epoch of cluster formation. This will allow addressing many question about the origin and evolution of shocks and magnetic fields in clusters. At the end we briefly review some of the first and very preliminary LOFAR results on clusters.
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- Assali, S., et al.
(författare)
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Crystal Phase Quantum Well Emission with Digital Control
- 2017
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 17:10, s. 6062-6068
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Tidskriftsartikel (refereegranskat)abstract
- One of the major challenges in the growth of quantum well and quantum dot heterostructures is the realization of atomically sharp interfaces. Nanowires provide a new opportunity to engineer the band structure as they facilitate the controlled switching of the crystal structure between the zinc-blende (ZB) and wurtzite (WZ) phases. Such a crystal phase switching results in the formation of crystal phase quantum wells (CPQWs) and quantum dots (CPQDs). For GaP CPQWs, the inherent electric fields due to the discontinuity of the spontaneous polarization at the WZ/ZB junctions lead to the confinement of both types of charge carriers at the opposite interfaces of the WZ/ZB/WZ structure. This confinement leads to a novel type of transition across a ZB flat plate barrier. Here, we show digital tuning of the visible emission of WZ/ZB/WZ CPQWs in a GaP nanowire by changing the thickness of the ZB barrier. The energy spacing between the sharp emission lines is uniform and is defined by the addition of single ZB monolayers. The controlled growth of identical quantum wells with atomically flat interfaces at predefined positions featuring digitally tunable discrete emission energies may provide a new route to further advance entangled photons in solid state quantum systems.
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| 13. |
- Bizzarri, N, et al.
(författare)
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Quality of training in cervical cancer radical surgery: a survey from the European Network of Young Gynaecologic Oncologists (ENYGO)
- 2022
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Ingår i: International journal of gynecological cancer : official journal of the International Gynecological Cancer Society. - : BMJ. - 1525-1438. ; 32:4, s. 494-501
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Tidskriftsartikel (refereegranskat)abstract
- The European Society of Gynaecological Oncology (ESGO) and partners are committed to improving the training for gynecologic oncology fellows. The aim of this survey was to assess the type and level of training in cervical cancer surgery and to investigate whether the Laparoscopic Approach to Cervical Cancer (LACC) trial results impacted training in radical surgery for gynecologic oncology fellows.MethodsIn June 2020, a 47-question electronic survey was shared with European Network of Young Gynaecologic Oncologists (ENYGO) members. Specialist fellows in obstetrics and gynecology, and gynecologic oncology, from high- and low-volume centers, who started training between January 1, 2017 and January 1, 2020 or started before January 1, 2017 but finished their training at least 6 months after the LACC trial publication (October 2018), were included.Results81 of 125 (64.8%) respondents were included. The median time from the start of the fellowship to completion of the survey was 28 months (range 6–48). 56 (69.1%) respondents were still fellows-in-training. 6 of 56 (10.7%) and 14 of 25 (56.0%) respondents who were still in training and completed the fellowship, respectively, performed ≥10 radical hysterectomies during their training. Fellows trained in an ESGO accredited center had a higher chance to perform sentinel lymph node biopsy (60.4% vs 30.3%; p=0.027). There was no difference in the mean number of radical hysterectomies performed by fellows during fellowship before and after the LACC trial publication (8±12.0 vs 7±8.4, respectively; p=0.46). A significant reduction in number of minimally invasive radical hysterectomies was noted when comparing the period before and after the LACC trial (38.5% vs 13.8%, respectively; p<0.001).ConclusionExposure to radical surgery for cervical cancer among gynecologic oncology fellows is low. Centralization of cervical cancer cases to high-volume centers may provide an increase in fellows’ exposure to radical procedures. The LACC trial publication was associated with a decrease in minimally invasive radical hysterectomies performed by fellows.
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- Bohnen, T., et al.
(författare)
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ScAlN nanowires : A cathodoluminescence study
- 2009
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Ingår i: JOURNAL OF CRYSTAL GROWTH. - : Elsevier BV. - 0022-0248. ; 311:11, s. 3147-3151
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Tidskriftsartikel (refereegranskat)abstract
- Wurtzite ScAlN nanowires, grown on a scandium nitride (ScN) thin film by hydride vapor phase epitaxy (HVPE), were analyzed by energy dispersive analysis of X-rays (EDX), CL, high resolution transmission electron spectroscopy (HRTEM), and scanning electron microscopy (SEM). The wires were grown along the [0 0 0 1] axis, had an average length of 1 mu m, a diameter between 50 and 150 run, and a ScAlN composition with a 95:5 Al:Sc ratio. Cathodoluminescence studies on the individual wires showed a sharp emission near 2.4 eV, originating from the Sc atoms in the aluminum nitride (AlN) matrix. The formation of such a semiconducting ScAlN alloy could present a new alternative to InAlN for optoelectronic applications operating in the 200-550 nm range.
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- Leibiger, Christine, et al.
(författare)
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Endolysosomal pathway activity protects cells from neurotoxic TDP-43
- 2018
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Ingår i: Microbial Cell. - : Shared Science Publishers OG. - 2311-2638. ; 5:4, s. 212-214
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The accumulation of protein aggregates in neurons is a typical pathological hallmark of the motor neuron disease amyotrophic lateral sclerosis (ALS) and of frontotemporal dementia (FTD). In many cases, these aggregates are composed of the 43 kDa TAR DNA-binding protein (TDP‑43). Using a yeast model for TDP‑43 proteinopathies, we observed that the vacuole (the yeast equivalent of lysosomes) markedly contributed to the degradation of TDP‑43. This clearance occurred via TDP‑43-containing vesicles fusing with the vacuole through the concerted action of the endosomal-vacuolar (or endolysosomal) pathway and autophagy. In line with its dominant role in the clearance of TDP‑43, endosomal-vacuolar pathway activity protected cells from the detrimental effects of TDP‑43. In contrast, enhanced autophagy contributed to TDP‑43 cytotoxicity, despite being involved in TDP‑43 degradation. TDP‑43’s interference with endosomal-vacuolar pathway activity may have two deleterious consequences. First, it interferes with its own degradation via this pathway, resulting in TDP‑43 accumulation. Second, it affects vacuolar proteolytic activity, which requires endosomal-vacuolar trafficking. We speculate that the latter contributes to aberrant autophagy. In sum, we propose that ameliorating endolysosomal pathway activity enhances cell survival in TDP‑43-associated diseases.
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| 18. |
- Leibiger, Christine, et al.
(författare)
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TDP-43 controls lysosomal pathways thereby determining its own clearance and cytotoxicity
- 2018
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Ingår i: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 27:9, s. 1593-1607
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Tidskriftsartikel (refereegranskat)abstract
- TDP-43 is a nuclear RNA-binding protein whose cytoplasmic accumulation is the pathological hallmark of amyotrophic lateral sclerosis (ALS). For a better understanding of this devastating disorder at the molecular level, it is important to identify cellular pathways involved in the clearance of detrimental TDP-43. Using a yeast model system, we systematically analyzed to which extent TDP-43-triggered cytotoxicity is modulated by conserved lysosomal clearance pathways. We observed that the lysosomal fusion machinery and the endolysosomal pathway, which are crucial for proper lysosomal function, were pivotal for survival of cells exposed to TDP-43. Interestingly, TDP-43 itself interfered with these critical TDP-43 clearance pathways. In contrast, autophagy played a complex role in this process. It contributed to the degradation of TDP-43 in the absence of endolysosomal pathway activity, but its induction also enhanced cell death. Thus, TDP-43 interfered with lysosomal function and its own degradation via lysosomal pathways, and triggered lethal autophagy. We propose that these effects critically contribute to cellular dysfunction in TDP-43 proteinopathies.
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| 19. |
- Rudberg, David, et al.
(författare)
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Diel Variability of CO2 Emissions From Northern Lakes
- 2021
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Ingår i: Journal of Geophysical Research - Biogeosciences. - Hoboken, United States : John Wiley & Sons. - 2169-8953 .- 2169-8961. ; 126:10
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Tidskriftsartikel (refereegranskat)abstract
- Lakes are generally supersaturated in carbon dioxide (CO2) and emitters of CO2 to the atmosphere. However, estimates of CO2 flux ((Formula presented.)) from lakes are seldom based on direct flux measurements and usually do not account for nighttime emissions, yielding risk of biased assessments. Here, we present direct (Formula presented.) measurements from automated floating chambers collected every 2–3 hr and spanning 115 24 hr periods in three boreal lakes during summer stratification and before and after autumn mixing in the most eutrophic lake of these. We observed 40%–67% higher mean (Formula presented.) in daytime during periods of surface water CO2 supersaturation in all lakes. Day-night differences in wind speed were correlated with the day-night (Formula presented.) differences in the two larger lakes, but in the smallest and most wind-sheltered lake peaks of (Formula presented.) coincided with low-winds at night. During stratification in the eutrophic lake, CO2 was near equilibrium and diel variability of (Formula presented.) insignificant, but after autumn mixing (Formula presented.) was high with distinct diel variability making this lake a net CO2 source on an annual basis. We found that extrapolating daytime measurements to 24 hr periods overestimated (Formula presented.) by up to 30%, whereas extrapolating measurements from the stratified period to annual rates in the eutrophic lake underestimated (Formula presented.) by 86%. This shows the importance of accounting for diel and seasonal variability in lake CO2 emission estimates.
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| 20. |
- Soletormos, Gyorgy, et al.
(författare)
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Clinical Use of Cancer Biomarkers in Epithelial Ovarian Cancer Updated Guidelines From the European Group on Tumor Markers
- 2016
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Ingår i: International Journal of Gynecological Cancer. - 1048-891X .- 1525-1438. ; 26:1, s. 43-51
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Tidskriftsartikel (refereegranskat)abstract
- Objective:To present an update of the European Group on Tumor Markers guidelines for serum markers in epithelial varian cancer. Methods: Systematic literature survey from 2008 to 2013. The articles were evaluated by level of evidence and strength of recommendation. Results: Because of its low sensitivity (50-62% for early stage epithelial ovarian cancer) and limited specificity (94-98.5%), cancer antigen (CA) 125 (CA125) is not recommended as a screening test in asymptomatic women. The Risk of Malignancy Index, which includes CA125, transvaginal ultrasound, and menopausal status, is recommended for the differential diagnosis of a pelvic mass. Because human epididymis protein 4 has been reported to have superior specificity to CA125, especially in premenopausal women, it may be considered either alone or as part of the risk of ovarian malignancy algorithm, in the differential diagnosis of pelvic masses, especially in such women. CA125 should be used to monitor response to first-line chemotherapy using the previously published criteria of the Gynecological Cancer Intergroup, that is, at least a 50% reduction of a pretreatment sample of 70 kU/L or greater. The value of CA125 in posttherapy surveillance is less clear. Although a prospective randomized trial concluded that early administration of chemotherapy based on increasing CA125 levels had no effect on survival, European Group on Tumor Markers state that monitoring with CA125 in this situation should occur, especially if the patient is a candidate for secondary cytoreductive surgery. Conclusions: At present, CA125 remains the most important biomarker for epithelial ovarian cancer, excluding tumors of mucinous origin.
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| 22. |
- Wen, Qingfeng, et al.
(författare)
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Lead-exposure associated miRNAs in humans and Alzheimer’s disease as potential biomarkers of the disease and disease processes
- 2022
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer’s disease (AD) is a neurodegenerative disease that eventually affects memory and behavior. The identification of biomarkers based on risk factors for AD provides insight into the disease since the exact cause of AD remains unknown. Several studies have proposed microRNAs (miRNAs) in blood as potential biomarkers for AD. Exposure to heavy metals is a potential risk factor for onset and development of AD. Blood cells of subjects that are exposed to lead detected in the circulatory system, potentially reflect molecular responses to this exposure that are similar to the response of neurons. In this study we analyzed blood cell-derived miRNAs derived from a general population as proxies of potentially AD-related mechanisms triggered by lead exposure. Subsequently, we analyzed these mechanisms in the brain tissue of AD subjects and controls. A total of four miRNAs were identified as lead exposure-associated with hsa-miR-3651, hsa-miR-150-5p and hsa-miR-664b-3p being negatively and hsa-miR-627 positively associated. In human brain derived from AD and AD control subjects all four miRNAs were detected. Moreover, two miRNAs (miR-3651, miR-664b-3p) showed significant differential expression in AD brains versus controls, in accordance with the change direction of lead exposure. The miRNAs’ gene targets were validated for expression in the human brain and were found enriched in AD-relevant pathways such as axon guidance. Moreover, we identified several AD relevant transcription factors such as CREB1 associated with the identified miRNAs. These findings suggest that the identified miRNAs are involved in the development of AD and might be useful in the development of new, less invasive biomarkers for monitoring of novel therapies or of processes involved in AD development.
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