1,769 research outputs found
0.596 Pb/s S, C, L-Band Transmission in a 125μm Diameter 4-Core Fiber using a Single Wideband Comb Source
We demonstrate 596.4 Tb/s over a standard cladding diameter fiber with 4 single-mode cores, using a single wideband optical comb source to provide 25 GHz spaced carriers over 120 nm range across S, C and L bands
Meaning behind measurement : self-comparisons affect responses to health related quality of life questionnaires
Purpose The subjective nature of quality of life is particularly pertinent to the domain of health-related quality of
life (HRQOL) research. The extent to which participants’ responses are affected by subjective information and personal reference frames is unknown. This study investigated how an elderly population living with a chronic metabolic bone disorder evaluated self-reported quality of life. Methods Participants (n = 1,331) in a multi-centre randomised controlled trial for the treatment of Paget’s disease completed annual HRQOL questionnaires, including the SF-36, EQ-5D and HAQ. Supplementary questions were added to reveal implicit reference frames used when making HRQOL evaluations. Twenty-one participants (11 male, 10 female, aged 59–91 years) were interviewed retrospectively about their responses to the supplementary questions, using cognitive interviewing techniques and semi-structured topic guides. Results The interviews revealed that participants used complex and interconnected reference frames to promote response shift when making quality of life evaluations. The choice of reference frame often reflected external factors unrelated to individual health. Many participants also stated that they were unclear whether to report general or disease-related HRQOL. Conclusions It is important, especially in clinical trials, to provide instructions clarifying whether ‘quality of life’ refers to disease-related HRQOL. Information on selfcomparison reference frames is necessary for the interpretation of responses to questions about HRQOL.The Chief Scientist Office of the Scottish Government Health Directorates,
The PRISM funding bodies (the Arthritis Research Campaign, the National Association for the Relief of Paget’s disease and the Alliance for Better Bone Health)Peer reviewedAuthor final versio
Scanning-probe spectroscopy of semiconductor donor molecules
Semiconductor devices continue to press into the nanoscale regime, and new
applications have emerged for which the quantum properties of dopant atoms act
as the functional part of the device, underscoring the necessity to probe the
quantum structure of small numbers of dopant atoms in semiconductors[1-3].
Although dopant properties are well-understood with respect to bulk
semiconductors, new questions arise in nanosystems. For example, the quantum
energy levels of dopants will be affected by the proximity of nanometer-scale
electrodes. Moreover, because shallow donors and acceptors are analogous to
hydrogen atoms, experiments on small numbers of dopants have the potential to
be a testing ground for fundamental questions of atomic and molecular physics,
such as the maximum negative ionization of a molecule with a given number of
positive ions[4,5]. Electron tunneling spectroscopy through isolated dopants
has been observed in transport studies[6,7]. In addition, Geim and coworkers
identified resonances due to two closely spaced donors, effectively forming
donor molecules[8]. Here we present capacitance spectroscopy measurements of
silicon donors in a gallium-arsenide heterostructure using a scanning probe
technique[9,10]. In contrast to the work of Geim et al., our data show
discernible peaks attributed to successive electrons entering the molecules.
Hence this work represents the first addition spectrum measurement of dopant
molecules. More generally, to the best of our knowledge, this study is the
first example of single-electron capacitance spectroscopy performed directly
with a scanning probe tip[9].Comment: In press, Nature Physics. Original manuscript posted here; 16 pages,
3 figures, 5 supplementary figure
Ten-Year Mortality and Cardiovascular Morbidity in the Finnish Diabetes Prevention Study—Secondary Analysis of the Randomized Trial
The Finnish Diabetes Prevention Study (DPS) was a randomized controlled trial, which showed that it is possible to prevent type 2 diabetes by lifestyle changes. The aim of the present study was to examine whether the lifestyle intervention had an effect on the ten-year mortality and cardiovascular morbidity in the DPS participants originally randomized either into an intervention or control group. Furthermore, we compared these results with a population-based cohort comprising individuals of varying glucose tolerance states.Middle-aged, overweight people with IGT (n = 522) were randomized into intensive intervention (including physical activity, weight reduction and dietary counseling), or control "mini-intervention" group. Median length of the intervention period was 4 years and the mean follow-up was 10.6 years. The population-based reference study cohort included 1881 individuals (1570 with normal glucose tolerance, 183 with IGT, 59 with screen-detected type 2 diabetes, 69 with previously known type 2 diabetes) with the mean follow-up of 13.8 years. Mortality and cardiovascular morbidity data were collected from the national Hospital Discharge Register and Causes of Death Register. Among the DPS participants who consented for register linkage (n = 505), total mortality (2.2 vs. 3.8 per 1000 person years, hazard ratio HR = 0.57, 95% CI 0.21-1.58) and cardiovascular morbidity (22.9 vs. 22.0 per 1000 person years, HR = 1.04, 95% CI 0.72-1.51) did not differ significantly between the intervention and control groups. Compared with the population-based cohort with impaired glucose tolerance, adjusted HRs were 0.21 (95% CI 0.09-0.52) and 0.39 (95% CI 0.20-0.79) for total mortality, and 0.89 (95% CI 0.62-1.27) and 0.87 (0.60-1.27) for cardiovascular morbidity in the intervention and control groups of the DPS, respectively. The risk of death in DPS combined cohort was markedly lower than in FINRISK IGT cohort (adjusted HR 0.30, 95% CI 0.17-0.54), but there was no significant difference in the risk of CVD (adjusted HR 0.88, 95% CI 0.64-1.21).Lifestyle intervention among persons with IGT did not decrease cardiovascular morbidity during the first 10 years of follow-up. However, the statistical power may not be sufficient to detect small differences between the intervention and control groups. Low total mortality among participants of the DPS compared with individuals with IGT in the general population could be ascribed to a lower cardiovascular risk profile at baseline and regular follow-up.ClinicalTrials.gov NCT00518167
Prediction of hybrid biomass in Arabidopsis thaliana by selected parental SNP and metabolic markers
A recombinant inbred line (RIL) population, derived from two Arabidopsis thaliana accessions, and the corresponding testcrosses with these two original accessions were used for the development and validation of machine learning models to predict the biomass of hybrids. Genetic and metabolic information of the RILs served as predictors. Feature selection reduced the number of variables (genetic and metabolic markers) in the models by more than 80% without impairing the predictive power. Thus, potential biomarkers have been revealed. Metabolites were shown to bear information on inherited macroscopic phenotypes. This proof of concept could be interesting for breeders. The example population exhibits substantial mid-parent biomass heterosis. The results of feature selection could therefore be used to shed light on the origin of heterosis. In this respect, mainly dominance effects were detected
Body size modifies the relationship between maternal serum 25-hydroxyvitamin D concentrations and gestational diabetes in high-risk women
Obesity increases the risk of low 25-hydroxyvitamin D (25(OH) D) concentrations and gestational diabetes (GDM). We explored whether the association between GDM and change in 25(OH) D concentrations measured in the first (7-18 wk) and second (20-27 wk) trimesters of pregnancy is dependent on maternal BMI. The study was a prospective study of 219 women with BMI of >= 30 kg/m2, a history of GDM, or both. The participants were stratified by first-trimester BMI: BMI of = 35 kg/m(2). In the BMI group >= 35 kg/m(2), those who did not develop GDM during the follow-up showed higher increase in serum 25(OH) D concentrations compared with women who developed GDM (43.2 vs. 11.5%; P <0.001). No associations between 25(OH) D concentrations and GDM were observed in other BMI groups. These findings give an important aspect of the role of maternal body size in the association between vitamin D and GDM in high-risk women.Peer reviewe
Exercise-induced left bundle branch block and subsequent mechanical left ventricular dyssynchrony -resolved with pharmacological therapy
A 53-year-old man with depressed ejection fraction (EF) of 35% and QRS width of 88 ms at rest was admitted to our institution with a complaint of exertional chest discomfort and dyspnea. During treadmill exercise, left bundle-branch block (LBBB) with a QRS width of 152 ms occurred at a heart rate of 100 bpm. During LBBB, the patient showed significant mechanical dyssynchrony as evidenced by a two-dimensional speckle tracking radial strain of 260 ms (≥130 ms), defined as the time difference between anterior-septum and posterior wall. Five-month after carvedilol and candesartan administration, EF had improved to 49% and LBBB did not occur until a heart rate of 126 bpm was attained during treadmill exercise. It appears that pharmacological therapy may be useful for patients with heart failure and exercise-induced LBBB
Changes in BMI-distribution from 1966–69 to 1995–97 in adolescents. The Young-HUNT study, Norway
Background
The aim of this study was to explore changes in the BMI-distribution over time among Norwegian adolescents.
Methods
Height and weight were measured in standardised ways and BMI computed in 6774 adolescents 14–18 years who participated in the Young-HUNT study, the youth part of the Health-study of Nord-Trondelag County, Norway in 1995–97. The results were compared to data from 8378 adolescents, in the same age group and living in the same geographical region, collected by the National Health Screening Service in 1966–69.
Results
From 1966–69 to 1995–97 there was an increased dispersion and a two-sided change in the BMI-distribution. Mean BMI did not increase in girls aged 14–17, but increased significantly in 18 year old girls and in boys of all ages. In both sexes and all ages there was a significant increase in the upper percentiles, but also a trend towards a decrease in the lowest percentiles. Height and weight increased significantly in both sexes and all ages.
Conclusion
The increased dispersion of the BMI-distribution with a substantial increase in upper BMI-percentiles followed the same pattern seen in other European countries and the United States. The lack of increase in mean BMI among girls, and the decrease in the lowest percentiles has not been acknowledged in previous studies, and may call for attention
Integrating isotopes and documentary evidence : dietary patterns in a late medieval and early modern mining community, Sweden
We would like to thank the Archaeological Research Laboratory, Stockholm University, Sweden and the Tandem Laboratory (Ångström Laboratory), Uppsala University, Sweden, for undertaking the analyses of stable nitrogen and carbon isotopes in both human and animal collagen samples. Also, thanks to Elin Ahlin Sundman for providing the δ13C and δ15N values for animal references from Västerås. This research (Bäckström’s PhD employment at Lund University, Sweden) was supported by the Berit Wallenberg Foundation (BWS 2010.0176) and Jakob and Johan Söderberg’s foundation. The ‘Sala project’ (excavations and analyses) has been funded by Riksens Clenodium, Jernkontoret, Birgit and Gad Rausing’s Foundation, SAU’s Research Foundation, the Royal Physiographic Society of Lund, Berit Wallenbergs Foundation, Åke Wibergs Foundation, Lars Hiertas Memory, Helge Ax:son Johnson’s Foundation and The Royal Swedish Academy of Sciences.Peer reviewedPublisher PD
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