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| 2. |
- Mattsson, Niklas, 1979, et al.
(författare)
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CSF biomarker variability in the Alzheimer's Association quality control program
- 2013
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 9:3, s. 251-261
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Tidskriftsartikel (refereegranskat)abstract
- Background The cerebrospinal fluid (CSF) biomarkers amyloid beta 1–42, total tau, and phosphorylated tau are used increasingly for Alzheimer's disease (AD) research and patient management. However, there are large variations in biomarker measurements among and within laboratories. Methods Data from the first nine rounds of the Alzheimer's Association quality control program was used to define the extent and sources of analytical variability. In each round, three CSF samples prepared at the Clinical Neurochemistry Laboratory (Mölndal, Sweden) were analyzed by single-analyte enzyme-linked immunosorbent assay (ELISA), a multiplexing xMAP assay, or an immunoassay with electrochemoluminescence detection. Results A total of 84 laboratories participated. Coefficients of variation (CVs) between laboratories were around 20% to 30%; within-run CVs, less than 5% to 10%; and longitudinal within-laboratory CVs, 5% to 19%. Interestingly, longitudinal within-laboratory CV differed between biomarkers at individual laboratories, suggesting that a component of it was assay dependent. Variability between kit lots and between laboratories both had a major influence on amyloid beta 1–42 measurements, but for total tau and phosphorylated tau, between-kit lot effects were much less than between-laboratory effects. Despite the measurement variability, the between-laboratory consistency in classification of samples (using prehoc-derived cutoffs for AD) was high (>90% in 15 of 18 samples for ELISA and in 12 of 18 samples for xMAP). Conclusions The overall variability remains too high to allow assignment of universal biomarker cutoff values for a specific intended use. Each laboratory must ensure longitudinal stability in its measurements and use internally qualified cutoff levels. Further standardization of laboratory procedures and improvement of kit performance will likely increase the usefulness of CSF AD biomarkers for researchers and clinicians.
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| 3. |
- Mente, A., et al.
(författare)
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Association of urinary sodium and potassium excretion with blood pressure
- 2014
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 371:7, s. 601-611
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Higher levels of sodium intake are reported to be associated with higher blood pressure. Whether this relationship varies according to levels of sodium or potassium intake and in different populations is unknown. METHODS: We studied 102,216 adults from 18 countries. Estimates of 24-hour sodium and potassium excretion were made from a single fasting morning urine specimen and were used as surrogates for intake. We assessed the relationship between electrolyte excretion and blood pressure, as measured with an automated device. RESULTS: Regression analyses showed increments of 2.11 mm Hg in systolic blood pressure and 0.78 mm Hg in diastolic blood pressure for each 1-g increment in estimated sodium excretion. The slope of this association was steeper with higher sodium intake (an increment of 2.58 mm Hg in systolic blood pressure per gram for sodium excretion >5 g per day, 1.74 mm Hg per gram for 3 to 5 g per day, and 0.74 mm Hg per gram for <3 g per day; P<0.001 for interaction). The slope of association was steeper for persons with hypertension (2.49 mm Hg per gram) than for those without hypertension (1.30 mm Hg per gram, P<0.001 for interaction) and was steeper with increased age (2.97 mm Hg per gram at >55 years of age, 2.43 mm Hg per gram at 45 to 55 years of age, and 1.96 mm Hg per gram at <45 years of age; P<0.001 for interaction). Potassium excretion was inversely associated with systolic blood pressure, with a steeper slope of association for persons with hypertension than for those without it (P<0.001) and a steeper slope with increased age (P<0.001). CONCLUSIONS: In this study, the association of estimated intake of sodium and potassium, as determined from measurements of excretion of these cations, with blood pressure was nonlinear and was most pronounced in persons consuming high-sodium diets, persons with hypertension, and older persons. (Funded by the Heart and Stroke Foundation of Ontario and others.).
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| 4. |
- Nemec, H., et al.
(författare)
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Bulk-like transversal electron mobility in heavily n-doped InP nanowires probed by terahertz spectroscopy
- 2014
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Ingår i: 2014 39th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2014. - 9781479938773
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Konferensbidrag (refereegranskat)abstract
- Waveguiding of excitation beam and propagation of THz beam in a complex gradient environment were studied in an array of InP nanowires. Measurements by time-resolved THz spectroscopy accompanied by Monte-Carlo calculations of the response of localized charges enabled determination of transversal electron mobility.
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| 5. |
- O'Donnell, M., et al.
(författare)
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Urinary sodium and potassium excretion, mortality, and cardiovascular events
- 2014
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 371:7, s. 612-623
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The optimal range of sodium intake for cardiovascular health is controversial. METHODS: We obtained morning fasting urine samples from 101,945 persons in 17 countries and estimated 24-hour sodium and potassium excretion (used as a surrogate for intake). We examined the association between estimated urinary sodium and potassium excretion and the composite outcome of death and major cardiovascular events. RESULTS: The mean estimated sodium and potassium excretion was 4.93 g per day and 2.12 g per day, respectively. With a mean follow-up of 3.7 years, the composite outcome occurred in 3317 participants (3.3%). As compared with an estimated sodium excretion of 4.00 to 5.99 g per day (reference range), a higher estimated sodium excretion (>/= 7.00 g per day) was associated with an increased risk of the composite outcome (odds ratio, 1.15; 95% confidence interval [CI], 1.02 to 1.30), as well as increased risks of death and major cardiovascular events considered separately. The association between a high estimated sodium excretion and the composite outcome was strongest among participants with hypertension (P=0.02 for interaction), with an increased risk at an estimated sodium excretion of 6.00 g or more per day. As compared with the reference range, an estimated sodium excretion that was below 3.00 g per day was also associated with an increased risk of the composite outcome (odds ratio, 1.27; 95% CI, 1.12 to 1.44). As compared with an estimated potassium excretion that was less than 1.50 g per day, higher potassium excretion was associated with a reduced risk of the composite outcome. CONCLUSIONS: In this study in which sodium intake was estimated on the basis of measured urinary excretion, an estimated sodium intake between 3 g per day and 6 g per day was associated with a lower risk of death and cardiovascular events than was either a higher or lower estimated level of intake. As compared with an estimated potassium excretion that was less than 1.50 g per day, higher potassium excretion was associated with a lower risk of death and cardiovascular events. (Funded by the Population Health Research Institute and others.).
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| 6. |
- Raza, Rizwan, et al.
(författare)
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Ce-0.8(SmZr)(0.2)O-2-carbonate nanocomposite electrolyte for solid oxide fuel cell
- 2014
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 38:4, s. 524-529
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Tidskriftsartikel (refereegranskat)abstract
- A nanocomposite Zr/Sm-codoped ceria electrolyte coated with K2CO3/Na2CO3 was synthesized by a coprecipitation method. The electrochemical study of the two-phase nanocomposite electrolytes with carbonate coated on the doped ceria shows high oxygen ion mobility at low temperatures (300-600 degrees C). The interface between the two constituent phases was studied by electrochemical impedance spectroscopy. Ionic conductivities were also measured with electrochemical impedance spectroscopy. The morphology and structure of composite electrolyte were characterized using field-emission scanning electron microscopy and X-ray diffraction. The fuel cell power density is 700 mW cm(-2), and an open-circuit voltage of 1.00 V is achieved at low temperatures (400-550 degrees C). This codoped approach with a second phase provides a good indication regarding overcoming the challenges of solid oxide fuel cell technology.
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| 8. |
- Teo, K., et al.
(författare)
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Prevalence of a healthy lifestyle among individuals with cardiovascular disease in high-, middle- and low-income countries: The Prospective Urban Rural Epidemiology (PURE) study
- 2013
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Ingår i: Journal of the American Medical Association. - : American Medical Association (AMA). - 0098-7484 .- 1538-3598. ; 309:15, s. 1613-21
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE: Little is known about adoption of healthy lifestyle behaviors among individuals with a coronary heart disease (CHD) or stroke event in communities across a range of countries worldwide. OBJECTIVE: To examine the prevalence of avoidance or cessation of smoking, eating a healthy diet, and undertaking regular physical activities by individuals with a CHD or stroke event. DESIGN, SETTING, AND PARTICIPANTS: Prospective Urban Rural Epidemiology (PURE) was a large, prospective cohort study that used an epidemiological survey of 153,996 adults, aged 35 to 70 years, from 628 urban and rural communities in 3 high-income countries (HIC), 7 upper-middle-income countries (UMIC), 3 lower-middle-income countries (LMIC), and 4 low-income countries (LIC), who were enrolled between January 2003 and December 2009. MAIN OUTCOME MEASURES: Smoking status (current, former, never), level of exercise (low, <600 metabolic equivalent task [MET]-min/wk; moderate, 600-3000 MET-min/wk; high, >3000 MET-min/wk), and diet (classified by the Food Frequency Questionnaire and defined using the Alternative Healthy Eating Index). RESULTS: Among 7519 individuals with self-reported CHD (past event: median, 5.0 [interquartile range {IQR}, 2.0-10.0] years ago) or stroke (past event: median, 4.0 [IQR, 2.0-8.0] years ago), 18.5% (95% CI, 17.6%-19.4%) continued to smoke; only 35.1% (95% CI, 29.6%-41.0%) undertook high levels of work- or leisure-related physical activity, and 39.0% (95% CI, 30.0%-48.7%) had healthy diets; 14.3% (95% CI, 11.7%-17.3%) did not undertake any of the 3 healthy lifestyle behaviors and 4.3% (95% CI, 3.1%-5.8%) had all 3. Overall, 52.5% (95% CI, 50.7%-54.3%) quit smoking (by income country classification: 74.9% [95% CI, 71.1%-78.6%] in HIC; 56.5% [95% CI, 53.4%-58.6%] in UMIC; 42.6% [95% CI, 39.6%-45.6%] in LMIC; and 38.1% [95% CI, 33.1%-43.2%] in LIC). Levels of physical activity increased with increasing country income but this trend was not statistically significant. The lowest prevalence of eating healthy diets was in LIC (25.8%; 95% CI, 13.0%-44.8%) compared with LMIC (43.2%; 95% CI, 30.0%-57.4%), UMIC (45.1%, 95% CI, 30.9%-60.1%), and HIC (43.4%, 95% CI, 21.0%-68.7%). CONCLUSION AND RELEVANCE: Among a sample of patients with a CHD or stroke event from countries with varying income levels, the prevalence of healthy lifestyle behaviors was low, with even lower levels in poorer countries.
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| 9. |
- Yusuf, S., et al.
(författare)
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Cardiovascular risk and events in 17 low-, middle-, and high-income countries
- 2014
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 371:9, s. 818-27
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: More than 80% of deaths from cardiovascular disease are estimated to occur in low-income and middle-income countries, but the reasons are unknown. METHODS: We enrolled 156,424 persons from 628 urban and rural communities in 17 countries (3 high-income, 10 middle-income, and 4 low-income countries) and assessed their cardiovascular risk using the INTERHEART Risk Score, a validated score for quantifying risk-factor burden without the use of laboratory testing (with higher scores indicating greater risk-factor burden). Participants were followed for incident cardiovascular disease and death for a mean of 4.1 years. RESULTS: The mean INTERHEART Risk Score was highest in high-income countries, intermediate in middle-income countries, and lowest in low-income countries (P<0.001). However, the rates of major cardiovascular events (death from cardiovascular causes, myocardial infarction, stroke, or heart failure) were lower in high-income countries than in middle- and low-income countries (3.99 events per 1000 person-years vs. 5.38 and 6.43 events per 1000 person-years, respectively; P<0.001). Case fatality rates were also lowest in high-income countries (6.5%, 15.9%, and 17.3% in high-, middle-, and low-income countries, respectively; P=0.01). Urban communities had a higher risk-factor burden than rural communities but lower rates of cardiovascular events (4.83 vs. 6.25 events per 1000 person-years, P<0.001) and case fatality rates (13.52% vs. 17.25%, P<0.001). The use of preventive medications and revascularization procedures was significantly more common in high-income countries than in middle- or low-income countries (P<0.001). CONCLUSIONS: Although the risk-factor burden was lowest in low-income countries, the rates of major cardiovascular disease and death were substantially higher in low-income countries than in high-income countries. The high burden of risk factors in high-income countries may have been mitigated by better control of risk factors and more frequent use of proven pharmacologic therapies and revascularization. (Funded by the Population Health Research Institute and others.).
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