431 research outputs found
Microscope objective for imaging atomic strontium with 0.63 micrometer resolution
Imaging and manipulating individual atoms with submicrometer separation can
be instrumental for quantum simulation of condensed matter Hamiltonians and
quantum computation with neutral atoms. Quantum gas microscope experiments in
most cases rely on quite costly solutions. Here we present an open-source
design of a microscope objective for atomic strontium consisting solely of
off-the-shelf lenses that is diffraction-limited for 461nm light. A
prototype built with a simple stacking design is measured to have a resolution
of 0.63(4)m, which is in agreement with the predicted value. This
performance, together with the near diffraction-limited performance for
532nm light makes this design useful for both quantum gas microscopes and
optical tweezer experiments with strontium. Our microscope can easily be
adapted to experiments with other atomic species such as erbium, ytterbium, and
dysprosium, as well as Rydberg experiments with rubidium
Chronic Diseases among Older Cancer Survivors
Objective. To compare the occurrence of pre-existing and subsequent comorbidity among older cancer patients (≥60 years) with older non-cancer patients. Material and Methods. Each cancer patient (n=3835, mean age 72) was matched with four non-cancer patients in terms of age, sex, and practice. The occurrence of chronic diseases was assessed cross-sectionally (lifetime prevalence at time of diagnosis) and longitudinally (incidence after diagnosis) for all cancer patients and for breast, prostate, and colorectal cancer patients separately. Cancer and non-cancer patients were compared using logistic and Cox regression analysis. Results. The occurrence of the most common pre-existing and incident chronic diseases was largely similar in cancer and non-cancer patients, except for pre-existing COPD (OR 1.21, 95% CI 1.06–1.37) and subsequent venous thrombosis in the first two years after cancer diagnosis (HR 4.20, 95% CI 2.74–6.44), which were significantly more frequent (P<0.01) among older cancer compared to non-cancer patients. Conclusion. The frequency of multimorbidity in older cancer patients is high. However, apart from COPD and venous thrombosis, the incidence of chronic diseases in older cancer patients is similar compared to non-cancer patients of the same age, sex, and practice
Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial
Objective To determine the effectiveness of increasing the dietary content of soluble fibre (psyllium) or insoluble fibre (bran) in patients with irritable bowel syndrome
Advantages of the nested case-control design in diagnostic research
Abstract Background Despite its benefits, it is uncommon to apply the nested case-control design in diagnostic research. We aim to show advantages of this design for diagnostic accuracy studies. Methods We used data from a full cross-sectional diagnostic study comprising a cohort of 1295 consecutive patients who were selected on their suspicion of having deep vein thrombosis (DVT). We draw nested case-control samples from the full study population with case:control ratios of 1:1, 1:2, 1:3 and 1:4 (per ratio 100 samples were taken). We calculated diagnostic accuracy estimates for two tests that are used to detect DVT in clinical practice. Results Estimates of diagnostic accuracy in the nested case-control samples were very similar to those in the full study population. For example, for each case:control ratio, the positive predictive value of the D-dimer test was 0.30 in the full study population and 0.30 in the nested case-control samples (median of the 100 samples). As expected, variability of the estimates decreased with increasing sample size. Conclusion Our findings support the view that the nested case-control study is a valid and efficient design for diagnostic studies and should also be (re)appraised in current guidelines on diagnostic accuracy research.</p
Pilot study to test the feasibility of a trial design and complex intervention on PRIoritising MUltimedication in Multimorbidity in general practices (PRIMUMpilot).
Published onlineJournal ArticleThis is the final version of the article. Available from BMJ Publishing Group via the DOI in this record.OBJECTIVE: To improve medication appropriateness and adherence in elderly patients with multimorbidity, we developed a complex intervention involving general practitioners (GPs) and their healthcare assistants (HCA). In accordance with the Medical Research Council guidance on developing and evaluating complex interventions, we prepared for the main study by testing the feasibility of the intervention and study design in a cluster randomised pilot study. SETTING: 20 general practices in Hesse, Germany. PARTICIPANTS: 100 cognitively intact patients ≥65 years with ≥3 chronic conditions, ≥5 chronic prescriptions and capable of participating in telephone interviews; 94 patients completed the study. INTERVENTION: The HCA conducted a checklist-based interview with patients on medication-related problems and reconciled their medications. Assisted by a computerised decision-support system (CDSS), the GPs discussed medication intake with patients and adjusted their medication regimens. The control group continued with usual care. OUTCOME MEASURES: Feasibility of the intervention and required time were assessed for GPs, HCAs and patients using mixed methods (questionnaires, interviews and case vignettes after completion of the study). The feasibility of the study was assessed concerning success of achieving recruitment targets, balancing cluster sizes and minimising drop-out rates. Exploratory outcomes included the medication appropriateness index (MAI), quality of life, functional status and adherence-related measures. MAI was evaluated blinded to group assignment, and intra-rater/inter-rater reliability was assessed for a subsample of prescriptions. RESULTS: 10 practices were randomised and analysed per group. GPs/HCAs were satisfied with the interventions despite the time required (35/45 min/patient). In case vignettes, GPs/HCAs needed help using the CDSS. The study made no patients feel uneasy. Intra-rater/inter-rater reliability for MAI was excellent. Inclusion criteria were challenging and potentially inadequate, and should therefore be adjusted. Outcome measures on pain, functionality and self-reported adherence were unfeasible due to frequent missing values, an incorrect manual or potentially invalid results. CONCLUSIONS: Intervention and trial design were feasible. The pilot study revealed important limitations that influenced the design and conduct of the main study, thus highlighting the value of piloting complex interventions. TRIAL REGISTRATION NUMBER: ISRCTN99691973; Results.Funding has been provided by the German Federal Ministry of Education and Research, BMBF, grant number 01GK0702
Quality assessment of diagnostic before-after studies: development of methodology in the context of a systematic review
Clinical prediction models to support the diagnosis of asthma in primary care: a systematic review protocol
Validation and cultural adaptation of a German version of the Physicians' Reactions to Uncertainty scales
Contains fulltext :
51656.pdf ( ) (Open Access)BACKGROUND: The aim of the study was to examine the validity of a translated and culturally adapted version of the Physicians' Reaction to Uncertainty scales (PRU) in primary care physicians. METHODS: In a structured process, the original questionnaire was translated, culturally adapted and assessed after administering it to 93 GPs. Test-retest reliability was tested by sending the questionnaire to the GPs again after two weeks. RESULTS: The principal factor analysis confirmed the postulated four-factor structure underlying the 15 items. In contrast to the original version, item 5 achieved a higher loading on the 'concern about bad outcomes' scale. Consequently, we rearranged the scales. Good item-scale correlations were obtained, with Pearson's correlation coefficient ranging from 0.56-0.84. As regards the item-discriminant validity between the scales 'anxiety due to uncertainty' and 'concern about bad outcomes', partially high correlations (Pearson's correlation coefficient 0.02-0.69; p < 0.001) were found, indicating an overlap between both constructs. The assessment of internal consistency revealed satisfactory values; Cronbach's alpha of the rearranged version was 0.86 or higher for all scales. Test-retest-reliability, assessed by means of the intraclass-correlation-coefficient (ICC), exceeded 0.84, except for the 'reluctance to disclose mistakes to physicians' scale (ICC = 0.66). In this scale, some substantial floor effects occurred, with 29.3% of answers showing the lowest possible value. CONCLUSION: Dealing with uncertainty is an important issue in daily practice. The psychometric properties of the rearranged German version of the PRU are satisfying. The revealed floor effects do not limit the significance of the questionnaire. Thus, the German version of the PRU could contribute to the further evaluation of the impact of uncertainty in primary care physicians
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