341 research outputs found
Electrochemical detection of mercury, cadmium, lead, and copper using boron -doped diamond electrodes
Anodic stripping voltammetry (ASV) and boron-doped diamond (BDD) electrodes were used to detect mercury, cadmium, lead, and copper at low part-per-billion (ppb) concentrations. Two types of BDD electrodes were used, free-standing polished electrodes, and unpolished BDD films grown on silicon substrates. The electrochemical detection of mercury was difficult in all of the matrices investigated: nitrate, chloride, thiocyanate, phosphate, and sulfate. Precipitation of mercuric or mercurous salts on the electrode surface was the likely cause. The addition of an auxiliary element improved the detection of mercury. The detection of cadmium and lead was more straightforward. The addition of copper improved the detection of lead, but not cadmium. The BDD electrode was used to determine the complexing capacity of a river water sample for lead. The application of ultrasound during the deposition step of ASV improved the detection of cadmium, but eventually damaged both types of BDD electrodes
Identifying Web Tables - Supporting a Neglected Type of Content on the Web
The abundance of the data in the Internet facilitates the improvement of
extraction and processing tools. The trend in the open data publishing
encourages the adoption of structured formats like CSV and RDF. However, there
is still a plethora of unstructured data on the Web which we assume contain
semantics. For this reason, we propose an approach to derive semantics from web
tables which are still the most popular publishing tool on the Web. The paper
also discusses methods and services of unstructured data extraction and
processing as well as machine learning techniques to enhance such a workflow.
The eventual result is a framework to process, publish and visualize linked
open data. The software enables tables extraction from various open data
sources in the HTML format and an automatic export to the RDF format making the
data linked. The paper also gives the evaluation of machine learning techniques
in conjunction with string similarity functions to be applied in a tables
recognition task.Comment: 9 pages, 4 figure
Exercise Fails to Improve Neurocognition in Depressed Middle-Aged and Older Adults
Purpose: Although cross-sectional studies have demonstrated an association between higher levels of aerobic fitness and improved neurocognitive function, there have been relatively few interventional studies investigating this relationship, and results have been inconsistent. We assessed the effects of aerobic exercise on neurocognitive function in a randomized controlled trial of patients with major depressive disorder (MDD). Methods: Two-hundred and two sedentary men (n = 49) and women (n = 153), aged 40 yr and over and who met diagnostic criteria for MDD, were randomly assigned to the following: a) supervised exercise, b) home-based exercise, c) sertraline, or d) placebo pill. Before and after 4 months of treatment, participants completed measures of: Executive Function (Trail Making Test BA difference score, Stroop Color/Word, Ruff 2 & 7 Test, Digit Symbol), Verbal Memory (Logical Memory, Verbal Paired Associates), and Verbal Fluency/Working Memory (Animal Naming, Controlled Oral Word Association Test, Digit Span). Multivariate analyses of covariance were performed to test the effects of treatment on posttreatment neuropsychological test scores, with baseline neuropsychological test scores, age, education, and change in depression scores entered as covariates. Results: The performance of exercise participants was no better than participants receiving placebo across all neuropsychological tests. Exercise participants performed better than participants receiving sertraline on tests of executive function but not on tests of verbal memory or verbal fluency/ working memory. Conclusions: We found little evidence to support the benefits of an aerobic exercise intervention on neurocognitive performance in patients with MDD. Originally published Medicine and Science in Sport and Exercise, Vol. 40, No. 7, July 200
The relationship between attitudes, beliefs and physical activity in older adults with knee pain: secondary analysis of a randomised controlled trial
Objective
To investigate how attitudes and beliefs about exercise relate to physical activity behavior in older adults with knee pain attributable to osteoarthritis (OA).
Methods
We conducted secondary data analyses of a randomized controlled trial of exercise interventions (ISRCTN: 93634563). Participants were adults ≥45 years old with knee pain attributable to OA (n = 514). Crude and adjusted cross‐sectional and longitudinal associations between baseline Self‐Efficacy for Exercise (SEE), Positive Outcome Expectations for Exercise (POEE), Negative Outcome Expectations for Exercise scores, and physical activity level, at baseline, 3 months, and 6 months (measured by self‐report using the Physical Activity Scale for the Elderly [PASE]), and important increases in physical activity level (from baseline to 6‐month followup) were investigated using multiple linear and logistic regression.
Results
Cross‐sectional associations were found between SEE and PASE scores (β = 4.14 [95% confidence interval (95% CI) 0.26, 8.03]) and POEE and PASE scores (β = 16.71 [95% CI 1.87, 31.55]), adjusted for sociodemographic and clinical covariates. Longitudinal associations were found between baseline SEE and PASE scores at 3 months (β = 4.95 [95% CI 1.02, 8.87]) and 6 months β = 3.71 (0.26, 7.16), and baseline POEE and PASE at 3 months (β = 34.55 [95% CI 20.13, 48.97]) and 6 months (β = 25.74 [95% CI 11.99, 39.49]), adjusted for baseline PASE score and intervention arm. However, no significant associations with important increases in physical activity level were found.
Conclusion
Greater exercise self‐efficacy and more positive exercise outcome expectations were associated with higher current and future physical activity levels. These may be targets for interventions aimed at increasing physical activity
A functional polymorphism in the 5HTR2C gene associated with stress responses also predicts incident cardiovascular events.
Previously we have shown that a functional nonsynonymous single nucleotide polymorphism (rs6318) of the 5HTR2C gene located on the X-chromosome is associated with hypothalamic-pituitary-adrenal axis response to a stress recall task, and with endophenotypes associated with cardiovascular disease (CVD). These findings suggest that individuals carrying the rs6318 Ser23 C allele will be at higher risk for CVD compared to Cys23 G allele carriers. The present study examined allelic variation in rs6318 as a predictor of coronary artery disease (CAD) severity and a composite endpoint of all-cause mortality or myocardial infarction (MI) among Caucasian participants consecutively recruited through the cardiac catheterization laboratory at Duke University Hospital (Durham, NC) as part of the CATHGEN biorepository. Study population consisted of 6,126 Caucasian participants (4,036 [65.9%] males and 2,090 [34.1%] females). A total of 1,769 events occurred (1,544 deaths and 225 MIs; median follow-up time = 5.3 years, interquartile range = 3.3-8.2). Unadjusted Cox time-to-event regression models showed, compared to Cys23 G carriers, males hemizygous for Ser23 C and females homozygous for Ser23C were at increased risk for the composite endpoint of all-cause death or MI: Hazard Ratio (HR) = 1.47, 95% confidence interval (CI) = 1.17, 1.84, p = .0008. Adjusting for age, rs6318 genotype was not related to body mass index, diabetes, hypertension, dyslipidemia, smoking history, number of diseased coronary arteries, or left ventricular ejection fraction in either males or females. After adjustment for these covariates the estimate for the two Ser23 C groups was modestly attenuated, but remained statistically significant: HR = 1.38, 95% CI = 1.10, 1.73, p = .005. These findings suggest that this functional polymorphism of the 5HTR2C gene is associated with increased risk for CVD mortality and morbidity, but this association is apparently not explained by the association of rs6318 with traditional risk factors or conventional markers of atherosclerotic disease
Cardiovascular disease risk, vascular health and erectile dysfunction among middle-aged, clinically depressed men
Erectile dysfunction (ED) is especially common in men with major depressive disorder (MDD). This study examined the extent to which risk factors for cardiovascular disease (CVD) and vascular dysfunction were associated with ED severity in a series of MDD patients
Systolic Blood Pressure, Socioeconomic Status, and Biobehavioral Risk Factors in a Nationally Representative US Young Adult Sample
In the National Longitudinal Study of Adolescent Health, a US longitudinal study of over 15,000 young adults, we examined the extent to which socioeconomic status is linked to systolic blood pressure, and whether biobehavioral risk factors mediate the association. Over 62% of the participants had systolic blood pressure >120 mmHg and 12% with systolic blood pressure >140 mmHg. Over 66% were classified as at least overweight (Body Mass Index>25 kg/m2), with over 36% meeting criteria for at least Class I obesity (Body Mass Index>30 kg/m2). Multivariate models showed that higher household income and being married were independently associated with lower systolic blood pressure. Higher body mass index, greater waist circumference, smoking, and higher alcohol intake were each independently associated with higher systolic blood pressure. Meditational analyses suggested that higher education level was associated with lower systolic blood pressure by way of lower body mass, smaller waist circumference, and lower resting heart rate. When these indirect effects were accounted for, education was not significantly associated with systolic blood pressure. In contrast, household income remained associated with systolic blood pressure even with control for all covariates. Results reinforce current public health concerns about rates of obesity and high blood pressure among young adults and suggest that disparities in education level and household income may play an important role the observed decrements in health. Identifying modifiable mechanisms that link socioeconomic status to systolic blood pressure using data from a large representative sample may improve risk stratification and guide the development of effective interventions
Cerebrovascular Risk Factors, Vascular Disease, and Neuropsychological Outcomes in Adults With Major Depression
To investigate the relationship of cerebrovascular risk factors (CVRFs), endothelial function, carotid artery intima medial thickness (IMT), and neuropsychological performance in a sample of 198 middle-aged and older individuals with major depressive disorder (MDD). Neuropsychological deficits are common among adults with MDD, particularly among those with CVRFs and potentially persons with subclinical vascular disease
Intima-media thickness and age of first depressive episode
Late life depression, including patients with vascular depression, has been associated with higher levels of intima-media thickness (IMT). Although individuals with vascular depression tend to report a later onset of depression, the relationship of IMT and age of first depressive episode is uncertain in younger adults. We therefore investigated the relationship between IMT and age of first depressive episode in a sample of 202 adults (age range 40−81 years) with major depression (MDD)
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