Measuring the Internal Temperature of a Levitated Nanoparticle in High Vacuum

The interaction of an object with its surrounding bath can lead to a coupling between the object's internal degrees of freedom and its center-of-mass motion. This coupling is especially important for nanomechanical oscillators, which are amongst the most promising systems for preparing macroscopic objects in quantum mechanical states. Here we exploit this coupling to derive the internal temperature of a levitated nanoparticle from measurements of its center-of-mass dynamics. For a laser-trapped silica particle in high vacuum we find an internal temperature of $1000(60)\,\mathrm{K}$. The measurement and control of the internal temperature of nanomechanical oscillators is of fundamental importance because blackbody emission sets limits to the coherence of macroscopic quantum states

Controlling the net charge on a nanoparticle optically levitated in vacuum

Optically levitated nanoparticles in vacuum are a promising model system to test physics beyond our current understanding of quantum mechanics. Such experimental tests require extreme control over the dephasing of the levitated particle's motion. If the nanoparticle carries a finite net charge, it experiences a random Coulomb force due to fluctuating electric fields. This dephasing mechanism can be fully excluded by discharging the levitated particle. Here, we present a simple and reliable technique to control the charge on an optically levitated nanoparticle in vacuum. Our method is based on the generation of charges in an electric discharge and does not require additional optics or mechanics close to the optical trap

CFTR genotype and maximal exercise capacity in cystic fibrosis: a cross-sectional study

RATIONALE: Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in human skeletal muscle cells. Variations of CFTR dysfunction among patients with CF may present an important determinant of aerobic exercise capacity in CF. Previous studies on the relationship between CFTR genotype and aerobic exercise capacity are scarce and contradictory. OBJECTIVES: This study was designed to explore factors influencing aerobic exercise capacity, expressed as peak oxygen consumption (VO2peak) with a specific focus on CFTR genotype in children and adults with CF. METHODS: In an international, multicenter cross-sectional study we collected data on CFTR genotype and cardiopulmonary exercise tests (CPET) in patients with CF eight years and older. CFTR mutations were classified into functional classes I-V. RESULTS: The final analysis included 726 patients (45% females, age 8 to 61 years, FEV1 16 to 123 % predicted) from 17 CF centers in North America, Europe, Australia and Asia whom all had both valid maximal CPET and complete CFTR genotype data. Overall, patients exhibited exercise intolerance (VO2peak, 77.3±19.1 % predicted), but values were comparable among different CFTR classes. Using linear regression analysis adjusted for relevant confounders, lung function and body mass index, but not CFTR genotype were the main predictors of VO2peak. CONCLUSIONS: We conclude that lung disease severity and reduced nutritional status rather than CFTR genotypes are the major determinants of aerobic exercise capacity in patients with CF

Usual energy and macronutrient intakes in 2-9-year-old European children

OBJECTIVE: Valid estimates of population intakes are essential for monitoring trends as well as for nutritional interventions, but such data are rare in young children. In particular, the problem of misreporting in dietary data is usually not accounted for. Therefore, this study aims to provide accurate estimates of intake distributions in European children. DESIGN: Cross-sectional setting-based multi-centre study. SUBJECTS: A total of 9560 children aged 2-9 years from eight European countries with at least one 24-h dietary recall (24-HDR). METHODS: The 24-HDRs were classified in three reporting groups based on age- and sex-specific Goldberg cutoffs (underreports, plausible reports, overreports). Only plausible reports were considered in the final analysis (N=8611 children). The National Cancer Institute (NCI)-Method was applied to estimate population distributions of usual intakes correcting for the variance inflation in short-term dietary data. RESULTS: The prevalence of underreporting (9.5%) was higher compared with overreporting (3.4%). Exclusion of misreports resulted in a shift of the energy and absolute macronutrient intake distributions to the right, and further led to the exclusion of extreme values, that is, mean values and lower percentiles increased, whereas upper percentiles decreased. The distributions of relative macronutrient intakes (% energy intake from fat/carbohydrates/proteins) remained almost unchanged when excluding misreports. Application of the NCI-Method resulted in markedly narrower intake distributions compared with estimates based on single 24-HDRs. Mean percentages of usual energy intake from fat, carbohydrates and proteins were 32.2, 52.1 and 15.7%, respectively, suggesting the majority of European children are complying with common macronutrient intake recommendations. In contrast, total water intake (mean: 1216.7 ml per day) lay below the recommended value for >90% of the children. CONCLUSION: This study provides recent estimates of intake distributions of European children correcting for misreporting as well as for the daily variation in dietary data. These data may help to assess the adequacy of young children's diets in Europe