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Sökning: WFRF:(Beck Stephan) > (2020-2023)

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1.
  • Beal, Jacob, et al. (författare)
  • Robust estimation of bacterial cell count from optical density
  • 2020
  • Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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2.
  • Abdelhalim, Mohamed A., et al. (författare)
  • Multicenter trans-Atlantic experience with fenestrated-branched endovascular aortic repair of chronic post-dissection thoracoabdominal aortic aneurysms
  • 2023
  • Ingår i: Journal of Vascular Surgery. - : Elsevier. - 0741-5214 .- 1097-6809. ; 78:4, s. 854-862.e1
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: This multicenter international study aimed to describe outcomes of fenestrated-branched endovascular aortic repairs (FB-EVAR) in a cohort of patients treated for chronic post-dissection thoracoabdominal aortic aneurysms (PD-TAAAs).METHODS: We reviewed the clinical data of all consecutive patients treated by FB-EVAR for repair of extent I to III PD-TAAAs in 16 centers from the United States and Europe (2008-2021). Data were extracted from institutional prospectively maintained databases and electronic patient records. All patients received off-the-shelf or patient-specific manufactured fenestrated-branched stent grafts. Endpoints were any cause mortality and major adverse events at 30 days, technical success, target artery (TA) patency, freedom from TA instability, minor (endovascular with <12 Fr sheath) and major (open or ≥12 Fr sheath) secondary interventions, patient survival, and freedom from aortic-related mortality (ARM).RESULTS: A total of 246 patients (76% male; median age, 67 years [interquartile range, 61-73 years]) were treated for extent I (7%), extent II (55%), and extent III (35%) PD-TAAAs by FB-EVAR. The median aneurysm diameter was 65 mm (interquartile range, 59-73 mm). Eighteen patients (7%) were octogenarians, 212 (86%) were American Society of Anesthesiologists class ≥3, and 21 (9%) presented with contained ruptured or symptomatic aneurysms. There were 917 renal-mesenteric vessels targeted by 581 fenestrations (63%) and 336 directional branches (37%), with a mean of 3.7 vessels per patient. Technical success was 96%. Mortality and rate of major adverse events at 30 days was 3% and 28%, including disabling complications such as new onset dialysis in 1%, major stroke in 1%, and permanent paraplegia in 2%. Mean follow-up was 24 months. Kaplan-Meier (KM) estimated patient survival at 3 and 5 years was 79% ± 6% and 65% ± 10%. KM estimated freedom from ARM was 95% ± 3% and 93% ± 5% at the same intervals. Unplanned secondary interventions were needed in 94 patients (38%), including minor procedures in 64 (25%) and major procedures in 30 (12%). There was one conversion to open surgical repair (<1%). KM estimated freedom from any secondary intervention was 44% ± 9% at 5 years. KM estimated primary and secondary TA patency were 93% ± 2% and 96% ± 1% at 5 years, respectively.CONCLUSIONS: FB-EVAR for chronic PD-TAAAs was associated with high technical success and a low rate of mortality (3%) and disabling complications at 30 days. Although the procedure is effective in the prevention of ARM, patient survival was low at 5 years (65%), likely due to the significant comorbidities in this cohort of patients. Freedom from secondary interventions at 5 years was 44%, although most procedures were minor. The significant rate of reinterventions highlights the need for continued patient surveillance.
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3.
  • Butorin, Sergei, et al. (författare)
  • Effect of carbon content on electronic structure of uranium carbides
  • 2023
  • Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • The electronic structure of UCx (x = 0.9, 1.0, 1.1, 2.0) was studied by means of x-ray absorption spectroscopy (XAS) at the CK edge and measurements in the high energy resolution fluorescence detection (HERFD) mode at the U M-4 and L-3 edges. The full-relativistic density functional theory calculations taking into account the 5f - 5f Coulomb interaction U and spin-orbit coupling (DFT+U+SOC) were also performed for UCand UC2. While the U L-3 HERFD-XAS spectra of the studied samples reveal little difference, the U M-4 HERFD-XAS spectra show certain sensitivity to the varying carbon content in uranium carbides. The observed gradual changes in the U M-4 HERFD spectra suggest an increase in the C2p-U 5f charge transfer, which is supported by the orbital population analysis in the DFT+U+ SOC calculations, indicating an increase in the U 5f occupancy in UC2 as compared to that in UC. On the other hand, the density of states at the Fermi level were found to be significantly lower in UC2, thus affecting the thermodynamic properties. Both the x-ray spectroscopic data (in particular, the CK XAS measurements) and results of the DFT+U+SOC calculations indicate the importance of taking into account U and SOC for the description of the electronic structure of actinide carbides.
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4.
  • Butorin, Sergei, et al. (författare)
  • X-ray spectroscopic study of chemical state in uranium carbides
  • 2022
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 29, s. 295-302
  • Tidskriftsartikel (refereegranskat)abstract
    • UC and UMeC2 (Me = Fe, Zr, Mo) carbides were studied by the high-energyresolution fluorescence-detected X-ray absorption (HERFD-XAS) technique at the U M-4 and L-3 edges. Both U M-4 and L-3 HERFD-XAS reveal some differences between UMeC2 and UC; there are differences also between the M-4 and L-3 edge results for both types of carbide in terms of the spectral width and energy position. The observed differences are attributed to the consequences of the U 5f, 6d-4d(3d) hybridization in UMeC2. Calculations of the U M-4 HERFD-XAS spectra were also performed using the Anderson impurity model (AIM). Based on the analysis of the data, the 5f occupancy in the ground state of UC was estimated to be 3.05 electrons. This finding is also supported by the analysis of U N-4,N-5 XAS of UC and by the results of the AIM calculations of the U 4f X-ray photoelectron spectrum of UC.
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5.
  • Dias, N., et al. (författare)
  • Outcomes of Elective and Non-elective Fenestrated-branched Endovascular Aortic Repair for Treatment of Thoracoabdominal Aortic Aneurysms
  • 2023
  • Ingår i: Annals of Surgery. - : Lippincott Williams & Wilkins. - 0003-4932 .- 1528-1140. ; 278:4, s. 568-577, s. 568-577
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To describe outcomes after elective and non-elective fenestrated-branched endovascular aortic repair (FB-EVAR) for thoracoabdominal aortic aneurysms (TAAAs).Background: FB-EVAR has been increasingly utilized to treat TAAAs; however, outcomes after non-elective versus elective repair are not well described.Methods: Clinical data of consecutive patients undergoing FB-EVAR for TAAAs at 24 centers (2006-2021) were reviewed. Endpoints including early mortality and major adverse events (MAEs), all-cause mortality, and aortic-related mortality (ARM), were analyzed and compared in patients who had non-elective versus elective repair.Results: A total of 2603 patients (69% males; mean age 72 +/- 10 year old) underwent FB-EVAR for TAAAs. Elective repair was performed in 2187 patients (84%) and non-elective repair in 416 patients [16%; 268 (64%) symptomatic, 148 (36%) ruptured]. Non-elective FB-EVAR was associated with higher early mortality (17% vs 5%, P < 0.001) and rates of MAEs (34% vs 20%, P < 0.001). Median follow-up was 15 months ( interquartile range, 7-37 months). Survival and cumulative incidence of ARM at 3 years were both lower for non-elective versus elective patients (50 +/- 4% vs 70 +/- 1% and 21 +/- 3% vs 7 +/- 1%, P < 0.001). On multivariable analysis, non-elective repair was associated with increased risk of all-cause mortality ( hazard ratio, 1.92; 95% CI] 1.50-2.44; P < 0.001) and ARM (hazard ratio, 2.43; 95% CI, 1.63-3.62; P < 0.001).Conclusions: Non-elective FB-EVAR of symptomatic or ruptured TAAAs is feasible, but carries higher incidence of early MAEs and increased all-cause mortality and ARM than elective repair. Long-term follow-up is warranted to justify the treatment.
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6.
  • Dias-Neto, Marina, et al. (författare)
  • Comparison of single- and multistage strategies during fenestrated-branched endovascular aortic repair of thoracoabdominal aortic aneurysms
  • 2023
  • Ingår i: Journal of Vascular Surgery. - : MOSBY-ELSEVIER. - 0741-5214 .- 1097-6809. ; 77:6, s. 1588-1597
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: The aim of this study was to compare outcomes of single or multistage approach during fenestrated-branched endovascular aortic repair (FB-EVAR) of extensive thoracoabdominal aortic aneurysms (TAAAs).Methods: We reviewed the clinical data of consecutive patients treated by FB-EVAR for extent I to III TAAAs in 24 centers (2006-2021). All patients received a single brand manufactured patient-specific or off-the-shelf fenestrated-branched stent grafts. Staging strategies included proximal thoracic aortic repair, minimally invasive segmental artery coil embolization, temporary aneurysm sac perfusion and combinations of these techniques. Endpoints were analyzed for elective repair in patients who had a single-or multistage approach before and after propensity score adjustment for baseline differences, including the composite 30-day/in-hospital mortality and/or permanent paraplegia, major adverse event, patient survival, and freedom from aortic-related mortality.Results: A total of 1947 patients (65% male; mean age, 71 +/- 8 years) underwent FB-EVAR of 155 extent I (10%), 729 extent II (46%), and 713 extent III TAAAs (44%). A single-stage approach was used in 939 patients (48%) and a multistage approach in 1008 patients (52%). A multistage approach was more frequently used in patients undergoing elective compared with non-elective repair (55% vs 35%; P < .001). Staging strategies were proximal thoracic aortic repair in 743 patients (74%), temporary aneurysm sac perfusion in 128 (13%), minimally invasive segmental artery coil embolization in 10 (1%), and combinations in 127 (12%). Among patients undergoing elective repair (n = 1597), the composite endpoint of 30-day/in-hospital mortality and/or permanent paraplegia rate occurred in 14% of single-stage and 6% of multistage approach patients (P < .001). After adjustment with a propensity score, multistage approach was associated with lower rates of 30-day/in-hospital mortality and/or permanent paraplegia (odds ratio, 0.466; 95% confidence interval, 0.271-0.801; P = .006) and higher patient survival at 1 year (86.9 +/- 1.3% vs 79.6 +/- 1.7%) and 3 years (72.7 +/- 2.1% vs 64.2 +/- 2.3%; adjusted hazard ratio, 0.714; 95% confidence interval, 0.528-0.966; P = .029), compared with a single stage approach.Conclusions: Staging elective FB-EVAR of extent I to III TAAAs was associated with decreased risk of mortality and/or permanent paraplegia at 30 days or within hospital stay, and with higher patient survival at 1 and 3 years.
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7.
  • Mardor, Israel, et al. (författare)
  • Determining spontaneous fission properties by direct mass measurements with the FRS Ion Catcher
  • 2020
  • Ingår i: ND 2019. - : EDP Sciences. - 9782759891061
  • Konferensbidrag (refereegranskat)abstract
    • We present a direct method to measure fission product yield distributions (FPY) and isomeric yield ratios (IYR) for spontaneous fission (SF) fragments. These physical properties are of utmost importance to the understanding of basic nuclear physics, the astrophysical rapid neutron capture process ('r process') of nucle-osynthesis, neutron star composition, and nuclear reactor safety. With this method, fission fragments are produced by spontaneous fission from a source that is mounted in a cryogenic stopping cell (CSC), thermalized and stopped within it, and then extracted and transported to a multiple-reflection time-of-flight mass-spectrometer (MR-TOF-MS). We will implement the method at the FRS Ion Catcher (FRS-IC) at GSI (Germany), whose MR-TOF-MS relative mass accuracy (similar to 10(-7)) and resolving power (similar to 600,000 FWHM) are sufficient to separate all isobars and numerous isomers in the fission fragment realm. The system's essential element independence and its fast simultaneous mass measurement provide a new direct way to measure isotopic FPY distributions, which is complementary to existing methods. It will enable nuclide FPY measurements in the high fission peak, which is hardly accessible by current techniques. The extraction time of the CSC, tens of milliseconds, enables a direct measurement of independent fission yields, and a first study of the temporal dependence of FPY distributions in this duration range. The ability to resolve isomers will further enable direct extraction of numerous IYRs while performing the FPY measurements. The method has been recently demonstrated at the FRS-ICr for SF with a 37 kBq Cf-252 fission source, where about 70 different fission fragments have been identified and counted. In the near future, it will be used for systematic studies of SF with a higher-activity Cf-252 source and a Cm-248 source. The method can be implemented also for neutron induced fission at appropriate facilities.
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8.
  • Volkert, Dorothee, et al. (författare)
  • ESPEN practical guideline : Clinical nutrition and hydration in geriatrics
  • 2022
  • Ingår i: Clinical Nutrition. - : Elsevier. - 0261-5614 .- 1532-1983. ; 41:4, s. 958-989
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Malnutrition and dehydration are widespread in older people, and obesity is an increasing problem. In clinical practice, it is often unclear which strategies are suitable and effective in counter-acting these key health threats.Aim: To provide evidence-based recommendations for clinical nutrition and hydration in older persons in order to prevent and/or treat malnutrition and dehydration. Further, to address whether weight-reducing interventions are appropriate for overweight or obese older persons.Methods: This guideline was developed according to the standard operating procedure for ESPEN guidelines and consensus papers. A systematic literature search for systematic reviews and primary studies was performed based on 33 clinical questions in PICO format. Existing evidence was graded according to the SIGN grading system. Recommendations were developed and agreed in a multistage consensus process.Results: We provide eighty-two evidence-based recommendations for nutritional care in older persons, covering four main topics: Basic questions and general principles, recommendations for older persons with malnutrition or at risk of malnutrition, recommendations for older patients with specific diseases, and recommendations to prevent, identify and treat dehydration. Overall, we recommend that all older persons shall routinely be screened for malnutrition in order to identify an existing risk early. Oral nutrition can be supported by nursing interventions, education, nutritional counselling, food modifica-tion and oral nutritional supplements. Enteral nutrition should be initiated if oral, and parenteral if enteral nutrition is insufficient or impossible and the general prognosis is altogether favorable. Dietary restrictions should generally be avoided, and weight-reducing diets shall only be considered in obese older persons with weight-related health problems and combined with physical exercise. All older persons should be considered to be at risk of low-intake dehydration and encouraged to consume adequate amounts of drinks. Generally, interventions shall be individualized, comprehensive and part of a multimodal and multidisciplinary team approach.Conclusion: A range of effective interventions is available to support adequate nutrition and hydration in older persons in order to maintain or improve nutritional status and improve clinical course and quality of life. These interventions should be implemented in clinical practice and routinely used.
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9.
  • Waschitz, Y., et al. (författare)
  • Independent isotopic fission yields of Cf-252 spontaneous fission via mass measurements at the FRS Ion Catcher
  • 2023
  • Ingår i: 15th International Conference on Nuclear Data for Science and Technology, ND2022. - : EDP Sciences.
  • Konferensbidrag (refereegranskat)abstract
    • We present first preliminary results of a novel method for measuring independent isotopic fission yields (IIFYs) of spontaneous fission (SF) via direct mass measurements, at the FRS Ion Catcher (FRS -IC) at GSI. Fission products were generated from a Cf-252 source installed in a cryogenic stopping cell, and were identified and counted with the multiple-reflection time-of-flight mass spectrometer (MR-TOR-MS) of the FRS-IC, utilizing well-established measurement and data analysis methods. The MR-TOR-MS resolves isobars unambiguously, even with limited statistics, and its non-scanning nature ensures minimal relative systematic uncertainties amongst fission products. The analysis for extracting IIFYs includes isotope-dependent efficiency corrections for all components of the FRS -IC. In particular, we applied a self-consistent technique that takes into account the element-dependent survival efficiencies in the CSC, due to chemical reactions with the buffer gas. Our IIFY results, which cover several tens of fission products in the less -accessible high-mass peak (Z = 56 to 63) down to fission yields at the level of 10(-5), are generally similar to those of the nuclear database ENDF/B-VII.O. Nevertheless, they reveal some structures that are not observed in the database smooth trends. These are the first results of a planned campaign to investigate IIFY distributions of spontaneous fission at the FRS-IC. Upcoming experiments will extend our results to wider Z and N ranges, lower fission yields, and other spontaneously-fissioning actinides.
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