| 31. |
- Stojanovic, M. G., et al.
(författare)
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Localized modes in linear and nonlinear octagonal-diamond lattices with two flat bands
- 2020
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : AMER PHYSICAL SOC. - 2469-9926 .- 2469-9934. ; 102:2
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Tidskriftsartikel (refereegranskat)abstract
- We consider a two-dimensional octagonal-diamond network with a fine-tuned diagonal coupling inside the diamond-shaped unit cell. Its linear spectrum exhibits coexistence of two dispersive bands (DBs) and two flat bands (FBs), touching one of the DBs embedded between them. Analogous to the kagome lattice, one of the FBs will constitute the ground state of the system for a proper sign choice of the Hamiltonian. The system is characterized by two different flat-band fundamental octagonal compactons, originating from the destructive interference of fully geometric nature. In the presence of a nonlinear amplitude (on-site) perturbation, the singleoctagon linear modes continue into one-parameter families of nonlinear compact modes with the same amplitude and phase structure. However, numerical stability analysis indicates that all strictly compact nonlinear modes are unstable, either purely exponentially or with oscillatory instabilities, for weak and intermediate nonlinearities and sufficiently large system sizes. Stabilization may appear in certain ranges for finite systems and, for the compacton originating from the band at the spectral edge, also in a regime of very large focusing nonlinearities. In contrast to the kagome lattice, the latter compacton family will become unstable already for arbitrarily weak defocusing nonlinearity for large enough systems. We show analytically the existence of a critical system size consisting of 12 octagon rings, such that the ground state for weak defocusing nonlinearity is a stable single compacton for smaller systems, and a continuation of a nontrivial, noncompact linear combination of single compacton modes for larger systems. Investigating generally the different nonlinear localized (noncompact) mode families in the semi-infinite gap bounded by this FB, we find that, for increasing (defocusing) nonlinearity the stable ground state will continuously develop into an exponentially localized mode with two main peaks in antiphase. At a critical nonlinearity strength a symmetry-breaking pitchfork bifurcation appears, so that the stable ground state is single peaked for larger defocusing nonlinearities. We also investigate numerically the mobility of localized modes in this regime and find that the considered modes are generally immobile both with respect to axial and diagonal phase-gradient perturbations.
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| 32. |
- Abrahams, Harriët J. G., et al.
(författare)
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Moderators of the effect of psychosocial interventions on fatigue in women with breast cancer and men with prostate cancer : Individual patient data meta-analyses
- 2020
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Ingår i: Psycho-Oncology. - : Wiley. - 1057-9249 .- 1099-1611. ; 29:11, s. 1772-1785
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Forskningsöversikt (refereegranskat)abstract
- ObjectivePsychosocial interventions can reduce cancer‐related fatigue effectively. However, it is still unclear if intervention effects differ across subgroups of patients. These meta‐analyses aimed at evaluating moderator effects of (a) sociodemographic characteristics, (b) clinical characteristics, (c) baseline levels of fatigue and other symptoms, and (d) intervention‐related characteristics on the effect of psychosocial interventions on cancer‐related fatigue in patients with non‐metastatic breast and prostate cancer.MethodsData were retrieved from the Predicting OptimaL cAncer RehabIlitation and Supportive care (POLARIS) consortium. Potential moderators were studied with meta‐analyses of pooled individual patient data from 14 randomized controlled trials through linear mixed‐effects models with interaction tests. The analyses were conducted separately in patients with breast (n = 1091) and prostate cancer (n = 1008).ResultsStatistically significant, small overall effects of psychosocial interventions on fatigue were found (breast cancer: β = −0.19 [95% confidence interval (95%CI) = −0.30; −0.08]; prostate cancer: β = −0.11 [95%CI = −0.21; −0.00]). In both patient groups, intervention effects did not differ significantly by sociodemographic or clinical characteristics, nor by baseline levels of fatigue or pain. For intervention‐related moderators (only tested among women with breast cancer), statistically significant larger effects were found for cognitive behavioral therapy as intervention strategy (β = −0.27 [95%CI = −0.40; −0.15]), fatigue‐specific interventions (β = −0.48 [95%CI = −0.79; −0.18]), and interventions that only targeted patients with clinically relevant fatigue (β = −0.85 [95%CI = −1.40; −0.30]).ConclusionsOur findings did not provide evidence that any selected demographic or clinical characteristic, or baseline levels of fatigue or pain, moderated effects of psychosocial interventions on fatigue. A specific focus on decreasing fatigue seems beneficial for patients with breast cancer with clinically relevant fatigue.
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| 33. |
- Chen, Hao Yu, et al.
(författare)
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Association of FADS1/2 Locus Variants and Polyunsaturated Fatty Acids With Aortic Stenosis
- 2020
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Ingår i: JAMA cardiology. - : American Medical Association (AMA). - 2380-6583 .- 2380-6591. ; 5:6, s. 694-702
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Aortic stenosis (AS) has no approved medical treatment. Identifying etiological pathways for AS could identify pharmacological targets.Objective: To identify novel genetic loci and pathways associated with AS.Design, Setting, and Participants: This genome-wide association study used a case-control design to evaluate 44 703 participants (3469 cases of AS) of self-reported European ancestry from the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort (from January 1, 1996, to December 31, 2015). Replication was performed in 7 other cohorts totaling 256 926 participants (5926 cases of AS), with additional analyses performed in 6942 participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. Follow-up biomarker analyses with aortic valve calcium (AVC) were also performed. Data were analyzed from May 1, 2017, to December 5, 2019.Exposures: Genetic variants (615 643 variants) and polyunsaturated fatty acids (ω-6 and ω-3) measured in blood samples.Main Outcomes and Measures: Aortic stenosis and aortic valve replacement defined by electronic health records, surgical records, or echocardiography and the presence of AVC measured by computed tomography.Results: The mean (SD) age of the 44 703 GERA participants was 69.7 (8.4) years, and 22 019 (49.3%) were men. The rs174547 variant at the FADS1/2 locus was associated with AS (odds ratio [OR] per C allele, 0.88; 95% CI, 0.83-0.93; P = 3.0 × 10-6), with genome-wide significance after meta-analysis with 7 replication cohorts totaling 312 118 individuals (9395 cases of AS) (OR, 0.91; 95% CI, 0.88-0.94; P = 2.5 × 10-8). A consistent association with AVC was also observed (OR, 0.91; 95% CI, 0.83-0.99; P = .03). A higher ratio of arachidonic acid to linoleic acid was associated with AVC (OR per SD of the natural logarithm, 1.19; 95% CI, 1.09-1.30; P = 6.6 × 10-5). In mendelian randomization, increased FADS1 liver expression and arachidonic acid were associated with AS (OR per unit of normalized expression, 1.31 [95% CI, 1.17-1.48; P = 7.4 × 10-6]; OR per 5-percentage point increase in arachidonic acid for AVC, 1.23 [95% CI, 1.01-1.49; P = .04]; OR per 5-percentage point increase in arachidonic acid for AS, 1.08 [95% CI, 1.04-1.13; P = 4.1 × 10-4]).Conclusions and Relevance: Variation at the FADS1/2 locus was associated with AS and AVC. Findings from biomarker measurements and mendelian randomization appear to link ω-6 fatty acid biosynthesis to AS, which may represent a therapeutic target.
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| 34. |
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| 35. |
- Ljungman, Susanne, 1942, et al.
(författare)
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Retraining for prevention of peritonitis in peritoneal dialysis patients: A randomized controlled trial
- 2020
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Ingår i: Peritoneal Dialysis International. - : SAGE Publications. - 0896-8608 .- 1718-4304. ; 40:2, s. 141-152
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Tidskriftsartikel (refereegranskat)abstract
- Background: Peritonitis is more common in peritoneal dialysis (PD) patients nonadherent to the PD exchange protocol procedures than in compliant patients. We therefore investigated whether regular testing of PD knowledge with focus on infection prophylaxis could increase the time to first peritonitis (primary outcome) and reduce the peritonitis rate in new PD patients. Methods: This physician-initiated, open-label, parallel group trial took place at 57 centers in Sweden, Denmark, Norway, Finland, Estonia, Latvia, the Netherlands, and the United Kingdom from 2010 to 2015. New peritonitis-free PD patients were randomized using computer-generated numbers 1 month after the start of PD either to a control group (n = 331) treated according to center routines or to a retraining group (n = 340), which underwent testing of PD knowledge and skills at 1, 3, 6, 12, 18, 24, 30, and 36 months after PD start, followed by retraining if the goals were not achieved. Results: In all, 74% of the controls and 80% of the retraining patients discontinued the study. The groups did not differ significantly regarding cumulative incidence of first peritonitis adjusted for competing risks (kidney transplantation, transfer to hemodialysis and death; hazard ratio 0.84; 95% confidence interval (CI) 0.65-1.09) nor regarding peritonitis rate per patient year (relative risk 0.93; 95% CI 0.75-1.16). Conclusions: In this randomized controlled trial, we were unable to demonstrate that regular, targeted testing and retraining of new PD patients increased the time to first peritonitis or reduced the rate of peritonitis, as the study comprised patients with a low risk of peritonitis, was underpowered, open to type 1 statistical error, and contamination between groups.
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| 36. |
- O Gorman, Eamon, 1984, et al.
(författare)
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ALMA and VLA reveal the lukewarm chromospheres of the nearby red supergiants Antares and Betelgeuse
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 638
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Tidskriftsartikel (refereegranskat)abstract
- We first present spatially resolved ALMA and VLA continuum observations of the early-M red supergiant Antares to search for the presence of a chromosphere at radio wavelengths. We resolve the free-free emission of the Antares atmosphere at 11 unique wavelengths between 0.7 mm (ALMA band 8) and 10 cm (VLA S band). The projected angular diameter is found to continually increase with increasing wavelength, from a low of 50.7 mas at 0.7 mm up to a diameter of 431 mas at 10 cm, which corresponds to 1.35 and 11.6 times the photospheric angular diameter, respectively. All four ALMA measurements show that the shape of the atmosphere is elongated, with a flattening of 15% at a similar position angle. The disk-averaged gas temperature of the atmosphere initially rises from a value of 2700 K at 1.35 R∗ (i.e., 0.35 R∗ above the photosphere) to a peak value of 3800 K at ∼2.5 R∗, after which it then more gradually decreases to 1650 K at 11.6 R∗. The rise in gas temperature between 1.35 R∗ and ∼2.5 R∗ is evidence for a chromospheric temperature rise above the photosphere of a red supergiant. We detect a clear change in the spectral index across the sampled wavelength range, with the flux density Sν ν1.42 between 0.7 mm and 1.4 cm, which we associate with chromosphere-dominated emission, while the flux density Sν ν0.8 between 4.3 cm and 10 cm, which we associate with wind-dominated emission. We show that the Antares MOLsphere is transparent at our observed wavelengths, and the lukewarm chromosphere that we detect is therefore real and not just an average of the cool MOLsphere and hot ultraviolet emitting gas. We then perform nonlocal thermal equilibrium modeling of the far-ultraviolet radiation field of another early-M red supergiant, Betelgeuse, and find that an additional hot (i.e., > 7000 K) chromospheric photoionization component with a much smaller filling factor must also exist throughout the chromospheres of these stars.
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| 37. |
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| 38. |
- Bernes, E., et al.
(författare)
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S 2p and P 2p Core Level Spectroscopy of PPT Ambipolar Material and Its Building Block Moieties
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 124:127, s. 14510-14520
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Tidskriftsartikel (refereegranskat)abstract
- The near-edge X-ray absorption fine structure (NEXAFS and X-ray photoelectron (XP) spectra of gas-phase 2,8-bis-(diphenylphosphoryl)dibenzo[b,d]thiophene (PPT) and triphenylphosphine oxide (TPPO) have been measured at the S and P L-II,L-III-edge regions. The time-dependent density functional theory (TDDFT) based on the relativistic two-component zeroth-order regular approximation approach has been used to provide an assignment of the experimental spectra, giving the contribution of the spin-orbit splitting and of the molecular-field splitting to the sulfur and phosphor binding energies. Computed XP and NEXAFS spectra agree well with the experimental measurements. In going from dibenzothiophene and TPPO to PPT, the nature of the most intense S 2p and P 2p NEXAFS features are preserved; this trend suggests that the electronic and geometric behaviors of the S and P atoms in the two building block moieties are conserved in the more complex system of PPT. This work enables us to shed some light onto the structure of the P-O bond, a still highly debated topic in the chemical literature. Since the S 2p and P 2p NEXAFS intensities provide specific information on the higher-lying localized sigma*(C-S) and sigma*(P-O) virtual MOs, we have concluded that P 3d AOs are not involved in the formation of the P-O bond. Moreover, the results support the mechanism of negative hyperconjugation, by showing that transitions toward sigma*(P-O) states occur at lower energies with respect to those toward it pi*(P-O) states.
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| 39. |
- Chen, G., et al.
(författare)
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Augmentation of Bri2 molecular chaperone activity against amyloid-β reduces neurotoxicity in mouse hippocampus in vitro
- 2020
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Ingår i: Communications Biology. - : Nature Research. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Molecular chaperones play important roles in preventing protein misfolding and its potentially harmful consequences. Deterioration of molecular chaperone systems upon ageing are thought to underlie age-related neurodegenerative diseases, and augmenting their activities could have therapeutic potential. The dementia relevant domain BRICHOS from the Bri2 protein shows qualitatively different chaperone activities depending on quaternary structure, and assembly of monomers into high-molecular weight oligomers reduces the ability to prevent neurotoxicity induced by the Alzheimer-associated amyloid-β peptide 1-42 (Aβ42). Here we design a Bri2 BRICHOS mutant (R221E) that forms stable monomers and selectively blocks a main source of toxic species during Aβ42 aggregation. Wild type Bri2 BRICHOS oligomers are partly disassembled into monomers in the presence of the R221E mutant, which leads to potentiated ability to prevent Aβ42 toxicity to neuronal network activity. These results suggest that the activity of endogenous molecular chaperones may be modulated to enhance anti-Aβ42 neurotoxic effects.
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| 40. |
- van Santen, S. S., et al.
(författare)
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Fractures, Bone Mineral Density, and Final Height in Craniopharyngioma Patients with a Follow-up of 16 Years
- 2020
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Ingår i: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 105:4
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Tidskriftsartikel (refereegranskat)abstract
- Context: Pituitary hormonal deficiencies in patients with craniopharyngioma may impair their bone health. Objective: To investigate bone health in patients with craniopharyngioma. Design: Retrospective cross-sectional study. Setting: Dutch and Swedish referral centers. Patients: Patients with craniopharyngioma (n = 177) with available data on bone health after a median follow-up of 16 years (range, 1-62) were included (106 [60%] Dutch, 93 [53%] male, 84 [48%] childhood-onset disease). Main outcome measures: Fractures, dual X-ray absorptiometry-derived bone mineral density (BMD), and final height were evaluated. Low BMD was defined as T- or Z-score <=-1 and very low BMD as <=-2.5 or <=-2.0, respectively. Results: Fractures occurred in 31 patients (18%) and were more frequent in men than in women (26% vs. 8%, P = .002). Mean BMD was normal (Z-score total body 0.1 [range, -4.1 to 3.5]) but T- or Z-score <=-1 occurred in 47 (50%) patients and T-score <=-2.5 or Z-score <=-2.0 in 22 (24%) patients. Men received less often treatment for low BMD than women (7% vs. 18%, P = .02). Female sex (OR 0.3, P = .004) and surgery (odds ratio [OR], 0.2; P = .01) were both independent protective factors for fractures, whereas antiepileptic medication was a risk factor (OR, 3.6; P = .03), whereas T-score <=-2.5 or Z-score <=-2.0 was not (OR, 2.1; P = .21). Mean final height was normal and did not differ between men and women, or adulthood and childhood-onset patients. Conclusions: Men with craniopharyngioma are at higher risk than women for fractures. In patients with craniopharyngioma, a very low BMD (T-score <=-2.5 or Z-score <=-2.0) seems not to be a good predictor for fracture risk.
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