480 research outputs found
Focal-plane wavefront sensors for direct exoplanet imaging: theory, simulations and on-sky demonstrations
One of the key limitations of the direct imaging of exoplanets at small angular separations are quasi-static speckles that originate from evolving non-common path aberrations (NCPA) to which the primary adaptive optics system is inherently blind. The main focus of this thesis is the development and (on-sky) testing of integrated coronagraph and focal-plane wavefront-sensing solutions to deal with NCPA. First, we enable focal-plane wavefront sensing with vector-Apodizing Phase Plate coronagraph by integrating a pupil-plane amplitude asymmetry into the design. Low-order wavefront sensing is then demonstrated with a non-linear model-based algorithm and high-order wavefront with spatial Linear Dark Field Control. We introduce the polarization-encoded self-coherent camera, which is a new and more powerful variant of the self-coherent camera. Furthermore, we show through on-sky tests that the “Fast and Furious” focal-plane wavefront sensing algorithm is capable of measured and controlling the low-wind effect. Lastly, the vector speckle grid is presented and dramatically increases the signal-to-noise ration of exoplanet variability measurements. The ultimate goal of this thesis is to enable the direct imaging and characterization of rocky exoplanets with future extremely large telescopes. </p
Genetically determined higher TSH is associated with a lower risk of diabetes mellitus in individuals with low BMI
Context: Thyroid status is hypothesized to be causally related with the risk of diabetes mellitus (DM), but previous results were conflicting possibly because of a complex interaction between thyrotropin (TSH), body mass index (BMI) and DM.Objective: This work aims to investigate the causal association between thyroid status with DM and glucose homeostasis and to what extent this association is dependent on BMI.Methods: A mendelian randomization study was conducted of European-ancestry participants from the UK Biobank population. The present study involved 408895 individuals (mean age 57.4 years [SD 8.0], 45.9% men), of whom 19773 had DM. Genetic variants for circulatory TSH, free thyroxine (fT4) concentrations and BMI to calculate weighted genetic risk scores. The main outcome measures included self-reported DM-stratified analyses by BMI. Analyses were repeated for nonfasting glucose and glycated hemoglobin A(1c) (HbA(1c)) among individuals without DM.Results: Genetically determined TSH and fT4 levels were not associated with risk of DM in the total UK Biobank population. However, in analyses stratified on genetically determined BMI, genetically determined higher TSH, and not fT4, was associated with a lower risk for DM only in the low BMI group (odds ratio 0.91; 95% CI, 0.85-0.98 in low BMI; P value for interaction = .06). Similar results were observed for glucose and HbA(1c) among individuals without DM.Conclusion: TSH, but not fT4, is a potential causal risk factor for DM in individuals with genetically determined low BMI highlighting potential protective effects of TSH only in low-risk populations.Pathophysiology, epidemiology and therapy of agein
Perspectives and experiences of patients and healthcare professionals with geriatric assessment in chronic kidney disease: a qualitative study
Background Older patients with end-stage kidney disease (ESKD) often live with unidentified frailty and multimorbidity. Despite guideline recommendations, geriatric assessment is not part of standard clinical care, resulting in a missed opportunity to enhance (clinical) outcomes including quality of life in these patients. To develop routine geriatric assessment programs for patients approaching ESKD, it is crucial to understand patients' and professionals' experiences with and perspectives about the benefits, facilitators and barriers for geriatric assessment.MethodsIn this qualitative study, semi-structured focus group discussions were conducted with ESKD patients, caregivers and professionals. Participants were purposively sampled from three Dutch hospital-based study- and routine care initiatives involving geriatric assessment for (pre-)ESKD care. Transcripts were analysed inductively using thematic analysis.ResultsIn six focus-groups, participants (n=47) demonstrated four major themes: (1) Perceived characteristics of the older (pre)ESKD patient group. Patients and professionals recognized increased vulnerability and (cognitive) comorbidity, which is often unrelated to calendar age. Both believed that often patients are in need of additional support in various geriatric domains. (2) Experiences with geriatric assessment. Patients regarded the content and the time spent on the geriatric assessment predominantly positive. Professionals emphasized that assessment creates awareness among the whole treatment team for cognitive and social problems, shifting the focus from mainly somatic to multidimensional problems. Outcomes of geriatric assessment were observed to enhance a dialogue on suitability of treatment options, (re)adjust treatment and provide/seek additional (social) support. (3) Barriers and facilitators for implementation of geriatric assessment in routine care. Discussed barriers included lack of communication about goals and interpretation of geriatric assessment, burden for patients, illiteracy, and organizational aspects. Major facilitators are good multidisciplinary cooperation, involvement of geriatrics and multidisciplinary team meetings. (4) Desired characteristics of a suitable geriatric assessment concerned the scope and use of tests and timing of assessment.ConclusionsPatients and professionals were positive about using geriatric assessment in routine nephrology care. Implementation seems achievable, once barriers are overcome and facilitators are endorsed. Geriatric assessment in routine care appears promising to improve (clinical) outcomes in patients approaching ESKD.Clinical epidemiolog
Associations of Irritability With Functional Connectivity of Amygdala and Nucleus Accumbens in Adolescents and Young Adults With ADHD
OBJECTIVE: Irritability is a common characteristic in ADHD. We examined whether dysfunction in neural connections supporting threat and reward processing was related to irritability in adolescents and young adults with ADHD. METHOD: We used resting-state fMRI to assess connectivity of amygdala and nucleus accumbens seeds in those with ADHD (n = 34) and an age- and gender-matched typically-developing comparison group (n = 34). RESULTS: In those with ADHD, irritability was associated with atypical functional connectivity of both seed regions. Amygdala seeds showed greater connectivity with right inferior frontal gyrus and caudate/putamen, and less connectivity with precuneus. Nucleus accumbens seeds showed altered connectivity with middle temporal gyrus and precuneus. CONCLUSION: The irritability-ADHD presentation is associated with atypical functional connectivity of reward and threat processing regions with cognitive control and emotion processing regions. These patterns provide novel evidence for irritability-associated neural underpinnings in adolescents and young adults with ADHD. The findings suggest cognitive and behavioral treatments that address response to reward, including omission of an expected reward and irritability, may be beneficial for ADHD
Design of a consensus-based geriatric assessment tailored for older chronic kidney disease patients: results of a pragmatic approach
Purpose Unidentified cognitive decline and other geriatric impairments are prevalent in older patients with advanced chronic kidney disease (CKD). Despite guideline recommendation of geriatric evaluation, routine geriatric assessment is not common in these patients. While high burden of vascular disease and existing pre-dialysis care pathways mandate a tailored geriatric assessment, no consensus exists on which instruments are most suitable in this population to identify geriatric impairments. Therefore, the aim of this study was to propose a geriatric assessment, based on multidisciplinary consensus, to routinely identify major geriatric impairments in older people with advanced CKD. Methods A pragmatic approach was chosen, which included focus groups, literature review, inventory of current practices, an expert consensus meeting, and pilot testing. In preparation of the consensus meeting, we composed a project team and an expert panel (n = 33), drafted selection criteria for the selection of instruments, and assessed potential instruments for the geriatric assessment. Results Selection criteria related to general geriatric domains, clinical relevance, feasibility, and duration of the assessment. The consensus-assessment contains instruments in functional, cognitive, psychological, somatic, patient preferences, nutritional status, and social domains. Administration of (seven) patient questionnaires and (ten) professional-administered instruments, by nurse (practitioners), takes estimated 20 and 40 min, respectively. Results are discussed in a multidisciplinary meeting including at least nephrology and geriatric expertise, informing nephrology treatment decisions, and follow-up interventions among which comprehensive geriatric assessment. Conclusion This first multidisciplinary consensus on nephrology-tailored geriatric assessment intent to benefit clinical care and enhance research comparability for older patients with advanced CKD.Key Summary pointsAim To propose a consensus-based geriatric assessment for optimizing both routine care and research in older patients with advanced chronic kidney disease. Findings Using a pragmatic approach, we reached consensus on a suitable nephrology-tailored geriatric assessment to routinely identify major geriatric impairments in older patients with advanced chronic kidney disease. This geriatric assessment contains instruments in functional, cognitive, psychological, somatic, patient preferences, nutritional status, and social domains, and can be administered with patient questionnaires and professional-administered instruments by nurse (practitioners) in approximately 20 and 40 minutes, respectively. Message We propose a consensus test set for standardized nephrology-tailored geriatric assessment, which is currently being implemented in multiple hospitals and studies, to benefit clinical care for older patients with advanced chronic kidney disease and enhance research comparability.Nephrolog
First on-sky demonstration of spatial Linear Dark Field Control with the vector-Apodizing Phase Plate at Subaru/SCExAO
Instrumentatio
Predicting disease-related and patient-reported outcomes in older patients with breast cancer-a systematic review
The number of older patients with breast cancer has increased due to the aging of the general population. The use of a geriatric assessment in this population has been advocated in many studies and guidelines as it can be used to identify high risk populations for early mortality and toxicity. Additionally, geriatric parameters could predict relevant outcome measures. This systematic review summarizes all available evidence on predictive factors for various outcomes (disease-related and survival, toxicity, and patient-reported outcomes), with a special focus on geriatric parameters and patient-reported outcomes, in older patients with breast cancer. Studies were identified through systematic review of the literature published up to September 1st 2019 in the PubMed database and EMBASe. A total of 173 studies were included. Most studies investigated disease-related and survival outcomes (n = 123, 71%). Toxicity was investigated in 40 studies (23%) and a mere 15% (n = 26) investigated patient-reported outcomes. Various measures that can be derived from a geriatric assessment were predictive for survival endpoints. Furthermore, geriatric parameters were among the most frequently found predictors for toxicity and patient-reported outcomes. In conclusion, this study shows that geriatric parameters can predict survival, toxicity, and patient-reported outcomes in older patients with breast cancer. These findings can be used in daily clinical practice to identify patients at risk of early mortality, high risk of treatment toxicity or poor functional outcome after treatment. A minority of studies used relevant outcome measures for older patients, showing the need for studies that are tailored to the older population.(c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).Experimentele farmacotherapi
Impact of the COVID-19 pandemic on symptoms of anxiety and depression and health-related quality of life in older patients with chronic kidney disease
Background: Older patients with advanced chronic kidney disease are at increased risk for a severe course of the coronavirus disease-2019 (COVID-19) and vulnerable to mental health problems. We aimed to investigate prevalence and associated patient (demographic and clinical) characteristics of mental wellbeing (health-related quality of life [HRQoL] and symptoms of depression and anxiety) before and during the COVID-19 pandemic in older patients with advanced chronic kidney disease.Methods: An ongoing Dutch multicentre prospective cohort study enrols patients of >= 70 years with an eGFR < 20 mL/min/1.73m(2) from October 2018 onward. With additional questionnaires during the pandemic (May-June 2020), disease-related concerns about COVID-19 and general anxiety symptoms were assessed cross-sectionally, and depressive symptoms, HRQoL, and emotional symptoms longitudinally.Results: The 82 included patients had a median age of 77.5 years (interquartile range 73.9-82.1), 77% were male and none had tested positive for COVID-19. Cross-sectionally, 67% of the patients reported to be more anxious about COVID-19 because of their kidney disease, and 43% of the patients stated that their quality of life was reduced due to the COVID-19 pandemic. Compared to pre-COVID-19, the presence of depressive symptoms had increased (11 to 22%; p = .022) and physical HRQoL declined (M = 40.4, SD = 10.1 to M = 36.1, SD = 10.4; p < .001), particularly in males. Mental HRQoL (M = 50.3, SD = 9.6 to M = 50.4, SD = 9.9; p = .913) and emotional symptoms remained similar.Conclusions: Older patients with advanced chronic kidney disease suffered from disease-related anxiety about COVID-19, increased depressive symptoms and reduced physical HRQoL during the COVID-19 pandemic. The impact of the pandemic on this vulnerable patient group extends beyond increased mortality risk, and awareness of mental wellbeing is important.Clinical epidemiolog
Frailty and treatment decisions in older patients with vulvar cancer: a single-center cohort study
Introduction: Vulvar cancer is a disease that mainly affects older women. Frailty is an important predictor of outcomes and geriatric assessment can help tailor treatment decisions and improve outcomes. This study aims to assess the prevalence of frailty in older women with vulvar cancer, and how it relates to integrated geriatric care and treatment according to the oncological guidelines. Materials and Methods: A single-center cohort study was performed, among patients 70 years and older, who were diagnosed with vulvar cancer at Leiden University Medical Center, between January 2012 and May 2020. Data on geriatric assessment, treatment decision-making and treatment-related outcomes were collected. Results: Our study included 114 patients. Mean age was 79.7 years, and 52 patients (45.6%) were frail. Of the frail patients, 42.0% were referred to a geriatrician. In eight of these cases, the geriatrician was actively involved in weighing the benefit and harm of standard oncological treatment versus de-escalated treatment. Frailty, higher age, impairment in the somatic domain, cognitive impairment, and functional dependency were associated with referral to a geriatrician and with active involvement of a geriatrician in decision making. In 26 of frail patients (50.0%) oncological treatment was de-escalated. Frailty, higher age, impairment in the somatic domain, cognitive impairment, and functional dependency were associated with de-escalation of treatment. De-escalated treatment did not compromise survival. Discussion: Frailty is prevalent among older women with vulvar cancer and is associated with referral to a geriatrician and de-escalation of oncological treatment. While this reflects that it is deemed important to tailor treatment decision for frail patients, most frail patients are not routinely evaluated by a geriatrician. Further multidisciplinary collaboration and research is necessary to optimize tailored treatment decisions for this patient group.Metabolic health: pathophysiological trajectories and therap
Manifest covariance and the Hamiltonian approach to mass gap in (2+1)-dimensional Yang-Mills theory
In earlier work we have given a Hamiltonian analysis of Yang-Mills theory in
(2+1) dimensions showing how a mass gap could arise. In this paper,
generalizing and covariantizing from the mass term in the Hamiltonian analysis,
we obtain two manifestly covariant and gauge-invariant mass terms which can be
used in a resummation of standard perturbation theory to study properties of
the mass gap.Comment: Sections 1, 4 modified, part of section 2 moved to appendix, 19
pages, LaTe
- …