1,547 research outputs found
Endothelial Function Assessed by Digital Volume Plethysmography Predicts the Development and Progression of Type 2 Diabetes Mellitus
Background
Endothelial dysfunction is a consequence of type 2 diabetes mellitus, but it is unclear whether endothelial dysfunction of conductance versus resistance vessels may also precede type 2 diabetes mellitus development.
Methods and Results
In a populationâbased cohort of 15 010 individuals from the GHS (Gutenberg Health Study) (aged 35â74 years at enrollment in 2007â2012), we identified 1610 cases of incident preâdiabetes mellitus and 386 cases of incident type 2 diabetes mellitus by hemoglobin A1c (HbA1c) and/or medical history between 2012 and 2017. Endothelial function of conductance and resistance vessels was measured by flowâmediated dilation and digital volume plethysmographyâderived reactive hyperemia index, respectively. Multivariable regression modeling was used to estimate ÎČ coefficients of HbA1c levels at followâup and relative risks of incident (preâ)diabetes mellitus. Reactive hyperemia index was independently associated with HbA1c after multivariable adjustment for baseline HbA1c, sex, age, socioeconomic status, arterial hypertension, waist/height ratio, packâyears of smoking, nonâhighâdensity lipoprotein/highâdensity lipoprotein ratio, physical activity, family history of myocardial infarction/stroke, prevalent cardiovascular disease, medication use, and Câreactive protein (ÎČ=â0.020; P=0.0029). The adjusted relative risk per SD decline in reactive hyperemia index was 1.08 (95% CI, 1.02â1.15; P=0.012) for incident preâdiabetes mellitus and 1.16 (95% CI, 1.01â1.34; P=0.041) for incident type 2 diabetes mellitus. Flowâmediated dilation independently increased the relative risk for developing preâdiabetes mellitus by 8% (95% CI, 1.02â1.14; P=0.012), but it was not independently associated with incident type 2 diabetes mellitus (relative risk, 1.01; 95% CI, 0.86â1.19; P=0.92) and with HbA1c (ÎČ=â0.003; P=0.59).
Conclusions
Endothelial dysfunction of resistance rather than conductance vessels may precede the development of (preâ)diabetes mellitus. Assessment of endothelial function by digital volume plethysmography may help to identify subjects at risk for development of type 2 diabetes mellitus
Spatial imaging of the spin Hall effect and current-induced polarization in two-dimensional electron gases
Spin-orbit coupling in semiconductors relates the spin of an electron to its
momentum and provides a pathway for electrically initializing and manipulating
electron spins for applications in spintronics and spin-based quantum
information processing. This coupling can be regulated with quantum confinement
in semiconductor heterostructures through band structure engineering. Here we
investigate the spin Hall effect and current-induced spin polarization in a
two-dimensional electron gas confined in (110) AlGaAs quantum wells using Kerr
rotation microscopy. In contrast to previous measurements, the spin Hall
profile exhibits complex structure, and the current-induced spin polarization
is out-of-plane. The experiments map the strong dependence of the
current-induced spin polarization to the crystal axis along which the electric
field is applied, reflecting the anisotropy of the spin-orbit interaction.
These results reveal opportunities for tuning a spin source using quantum
confinement and device engineering in non-magnetic materials.Comment: Accepted for publication (2005
Western Indian Ocean marine and terrestrial records of climate variability: a review and new concepts on land-ocean interactions since AD 1660
We examine the relationship between three tropical and two subtropical western Indian Ocean coral oxygen isotope time series to surface air temperatures (SAT) and rainfall over India, tropical East Africa and southeast Africa. We review established relationships, provide new concepts with regard to distinct rainfall seasons, and mean annual temperatures. Tropical corals are coherent with SAT over western India and East Africa at interannual and multidecadal periodicities. The subtropical corals correlate with Southeast African SAT at periodicities of 16â30 years. The relationship between the coral records and land rainfall is more complex. Running correlations suggest varying strength of interannual teleconnections between the tropical coral oxygen isotope records and rainfall over equatorial East Africa. The relationship with rainfall over India changed in the 1970s. The subtropical oxygen isotope records are coherent with South African rainfall at interdecadal periodicities. Paleoclimatological reconstructions of land rainfall and SAT reveal that the inferred relationships generally hold during the last 350 years. Thus, the Indian Ocean corals prove invaluable for investigating landâocean interactions during past centuries
Metabolic design of macroscopic bioreaction models: application to Chinese hamster ovary cells
The aim of this paper is to present a systematic methodology to design macroscopic bioreaction models for cell cultures based upon metabolic networks. The cell culture is seen as a succession of phases. During each phase, a metabolic network represents the set of reactions occurring in the cell. Then, through the use of the elementary flux modes, these metabolic networks are used to derive macroscopic bioreactions linking the extracellular substrates and products. On this basis, as many separate models are obtained as there are phases. Then, a complete model is obtained by smoothly switching from model to model. This is illustrated with batch cultures of Chinese hamster ovary cells
No association between islet cell antibodies and coxsackie B, mumps, rubella and cytomegalovirus antibodies in non-diabetic individuals aged 7â19 years
Viral antibodies were tested in a cohort of 44 isletcell antibody-positive individuals age 7â19 years, and 44 of their islet cell antibody-negative age and sex-matched classmates selected from a population study of 4208 pupils who had been screened for islet cell antibodies. Anti-coxsackie B1-5 IgM responses were detected in 14 of 44 (32%) of the islet cell antibody-positive subjects and in 7 of 44 (16%) control subjects. This difference did not reach the level of statistical significance. None of the islet cell antibody-positive subjects had specific IgM antibodies to mumps, rubella, or cytomegalovirus. There was also no increase in the prevalence or the mean titres of anti-mumps-IgG or IgA and anti-cytomegalovirus-IgG in islet cell antibody-positive subjects compared to control subjects. These results do not suggest any association between islet cell antibodies, and possibly insulitis, with recent mumps, rubella or cytomegalo virus infection. Further studies are required to clarify the relationship between islet cell antibodies and coxsackie B virus infections
Patterns of Pacific decadal variability recorded by Indian Ocean corals
We investigate Pacific Decadal Oscillation (PDO) signals recorded by two bimonthly resolved coral ÎŽ18O series from La RĂ©union and Ifaty (West Madagascar), Indian Ocean from 1882 to 1993. To isolate the main PDO frequencies, we apply a band pass filter to the time series passing only periodicities from 16 to 28 years. We investigate the covariance patterns of the coral time series with sea surface temperature (SST) and sea level pressure (SLP) of the Indian and Pacific Oceans. In addition, the empirical orthogonal functions of the filtered SST and SLP fields (single and coupled) are related to the filtered coral times series. The covariance maps show the typical PDO pattern for SST and SLP, confirming the coupling between the Indian and Pacific Oceans. Both corals show the strongest signal in boreal summer. The La RĂ©union (Ifaty) coral better records SST (SLP) than SLP (SST) pattern variability. We suggest that the filtered La RĂ©union coral ÎŽ18O represents ÎŽ18O of seawater that varies with the South Equatorial Current, which, in turn, is linked with the SST PDO. The filtered Ifaty coral ÎŽ18O represents SST and is remotely linked with the SLP PDO variability. A combined coral record of the Ifaty and La RĂ©union boreal summer ÎŽ18O series explains about 64% of the variance of the coupled SST/SLP PDO time series
Herd-level animal management factors associated with the occurrence of bovine neonatal pancytopenia in calves in a multicountry study
Since 2007, mortality associated with a previously unreported haemorrhagic disease has been observed in young calves in several European countries. The syndrome, which has been named âbovine neonatal pancytopeniaâ (BNP), is characterised by thrombocytopenia, leukocytopenia and a panmyelophthisis. A herd-level case-control study was conducted in four BNP affected countries (Belgium, France, Germany and the Netherlands) to identify herd management risk factors for BNP occurrence. Data were collected using structured face-to-face and telephone interviews of farm managers and their local veterinarians. In total, 363 case farms and 887 control farms were included in a matched multivariable conditional logistic regression analysis. Case-control status was strongly associated with the odds of herd level use of the vaccine PregSureÂź BVD (PregSure, Pfizer Animal Health) (matched adjusted odds ratio (OR) 107.2; 95% CI: 41.0â280.1). This was also the case for the practices of feeding calves colostrum from the calfâs own dam (OR 2.0; 95% CI: 1.1â3.4) or feeding pooled colostrum (OR 4.1; 95% CI: 1.9â8.8). Given that the study had relatively high statistical power and represented a variety of cattle production and husbandry systems, it can be concluded with some confidence that no other herd level management factors are competent causes for a sufficient cause of BNP occurrence on herd level. It is suggested that genetic characteristics of the dams and BNP calves should be the focus of further investigations aimed at identifying the currently missing component causes that together with PregSure vaccination and colostrum feeding represent a sufficient cause for occurrence of BNP in calves
Predicting nursing home admission in the U.S: a meta-analysis
Background:
While existing reviews have identified significant predictors of nursing home admission, this meta-analysis attempted to provide more integrated empirical findings to identify predictors. The present study aimed to generate pooled empirical associations for sociodemographic, functional, cognitive, service use, and informal support indicators that predict nursing home admission among older adults in the U.S.
Methods:
Studies published in English were retrieved by searching the MEDLINE, PSYCINFO, CINAHL, and Digital Dissertations databases using the keywords: "nursing home placement," "nursing home entry," "nursing home admission," and "predictors/institutionalization." Any reports including these key words were retrieved. Bibliographies of retrieved articles were also searched. Selected studies included sampling frames that were nationally- or regionally-representative of the U.S. older population.
Results:
Of 736 relevant reports identified, 77 reports across 12 data sources were included that used longitudinal designs and community-based samples. Information on number of nursing home admissions, length of follow-up, sample characteristics, analysis type, statistical adjustment, and potential risk factors were extracted with standardized protocols. Random effects models were used to separately pool the logistic and Cox regression model results from the individual data sources. Among the strongest predictors of nursing home admission were 3 or more activities of daily living dependencies (summary odds ratio [OR] = 3.25; 95% confidence interval [CI], 2.56â4.09), cognitive impairment (OR = 2.54; CI, 1.44â4.51), and prior nursing home use (OR = 3.47; CI, 1.89â6.37).
Conclusion:
The pooled associations provided detailed empirical information as to which variables emerged as the strongest predictors of NH admission (e.g., 3 or more ADL dependencies, cognitive impairment, prior NH use). These results could be utilized as weights in the construction and validation of prognostic tools to estimate risk for NH entry over a multi-year period
A prospective multi-center cohort study of acute non-displaced fractures of the scaphoid: operative versus non-operative treatment [NCT00205985]
BACKGROUND: Acute scaphoid fractures are common in active adults and do lead to reasonable time lost to work. One important goal of treatment is early return to work or sport. On this background, the adequate treatment of non-displaced acute scaphoid fractures is still under discussion. The aim of this study is to compare time to return to previous activity level comparing surgical versus non-surgical treatment of non-displaced acute scaphoid fractures. METHODS/DESIGN: The study is designed as a non-randomized multiple center cohort study including 12 sites in Germany and Austria. The inclusion period is planned to be 12 months with a follow up of 6 months. Allocation to operative or non-operative treatment is choosen by the patient together with his treating surgeon. The primary outcome is time to return to previous activity level adapted for loading of the wrist in daily life as measured by a newly developed questionnaire (PLDL-wrist). Factors identified a priori to be associated with the outcome, e.g., poverty status, age, education, smoking status, gender, and occupation, are measured to ensure adequate control for their potential confounding effects. DISCUSSION: The rationale and the design of a multiple center cohort study are presented. As it is not considered feasible to randomize patients in this study, potential confounding effects need to be controlled adequately
Linear and nonlinear optical properties of realistic quantum-wire structures: The dominant role of Coulomb correlation
A systematic analysis of the linear and nonlinear optical properties of realistic quantum wires is presented. The proposed theoretical approach, based on a set of generalized semiconductor Bloch equations, provides a full three-dimensional multisubband description of carrier-carrier correlation for any profile of the confinement potential, thus allowing a direct comparison with experiments on available structures. In agreement with previous investigations based on simplified one-dimensional models, our analysis shows that, also for realistic quantum-wire structures, electron-hole Coulomb correlation completely removes the one-dimensional band-edge singularities from the linear-absorption spectra. Moreover, we find that this effect is present also at high densities (corresponding to gain regimes) and contributes significantly in suppressing the ideal sharp features of the free-carrier density of states. The multisubband nature of available state-of-the-art structures is found to play a dominant role in determining the overall spectral shape in the whole density range
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