A Brownian-pumping model for oceanic trace metal scavenging: Evidence from Th isotopes

Two observed characteristics of Th isotope and stable metal sorption in natural aquatic systems are seemingly at odds with physico-chemical adsorption theory: (1) characteristic sorption times of days to weeks and (2) Kds which are inversely related in magnitude to particle concentrations. In addition, sorption rate constants are positiveiy correlated with particle concentrations and Kd. This paper presents a conceptual and mathematical model with which it is proposed that these metal sorption characteristics have the same underlying physical process in common: the coagulation of colloidal (nonfilterable) particles onto larger (filterable) particles. “Brownian pumping” (the transfer of truly dissolved metal species to filterable particles through a colloidal intermediate) consists of two rate steps: (1) rapid formation of metal/colloid surface site complexes (adsorption) and (2) slow coagulation of colloids with filterable particles. The Brownian-pumping model is tested against field and laboratory data. The field data, obtained from the literature, covers different regions of the oceans: deep ocean environments, euphotic zone, coastal and estuarine systems. The laboratory data involved 228Th sorption in suspensions of goethite and polystyrene latexes. Although the model has general applicability, results and discussions herein emphasize thorium isotope behavior. The Brownian-pumping model suggests that Th or other strongly sorbing elements may be useful as in situ “coagulometers” either at relatively high (e.g., greater than 5–10 mg/l) particle concentrations or when the mass ratio of colloids (C*p) to filterable particles (Cp) is known. The model also indicates that the ratio of colloids to filterable particles in marine systems, may be, by a first approximation, described by the relationship log C*p = 0.7 log Cp – 2.6 (in units of kg/l)

A Sensitive Determination of Iodine Species, Including Organoiodine, for Freshwater and Seawater Samples Using High Performance Liquid Chromatography and Spectrophotometric Detection

In order to more effectively use iodine isotope ratios, 129I/127I, as hydrological and geochemical tracers in aquatic systems, a new HPLC method was developed for the determination of iodine speciation. The dissolved iodine species that dominate natural water systems are iodide, iodate, and organic iodine. Using this new method, iodide was determined directly by combining anion exchange chromatography and spectrophotometry. Iodate and the total of organic iodine species are determined as iodide, with minimal sample preparation, compared to existing methods. The method has been successfully applied to determine iodide, iodate as the difference of total inorganic iodide and iodide after reduction of the sample, and organic iodine as the difference of total iodide (after organic decomposition and reduction) and total inorganic iodide. Analytical accuracy was tested (1) against certified reference material SRM 1549, powdered milk (NIST), (2) through the method of standard additions, and (3) by comparison to values of environmental waters measured independently by ICP-MS. The method has been successfully applied to measure the concentrations of iodide species in rain, surface and groundwater, estuarine and seawater samples. The detection limit was ~1 nM (0.2 ppb), with less than 3% relative standard deviation for samples determined by standard additions to an iodide solution of 20 nM in 0.1 M NaCl. This technique is one of the few methods sensitive enough to accurately quantify stable iodine species at nanomolar concentrations in aquatic systems across a range of matrices, and to quantitatively measure organic iodine

Improving blood pressure control through pharmacist interventions: a meta-analysis of randomized controlled trials.

BACKGROUND: Control of blood pressure (BP) remains a major challenge in primary care. Innovative interventions to improve BP control are therefore needed. By updating and combining data from 2 previous systematic reviews, we assess the effect of pharmacist interventions on BP and identify potential determinants of heterogeneity. METHODS AND RESULTS: Randomized controlled trials (RCTs) assessing the effect of pharmacist interventions on BP among outpatients with or without diabetes were identified from MEDLINE, EMBASE, CINAHL, and CENTRAL databases. Weighted mean differences in BP were estimated using random effect models. Prediction intervals (PI) were computed to better express uncertainties in the effect estimates. Thirty-nine RCTs were included with 14 224 patients. Pharmacist interventions mainly included patient education, feedback to physician, and medication management. Compared with usual care, pharmacist interventions showed greater reduction in systolic BP (-7.6 mm Hg, 95% CI: -9.0 to -6.3; I(2)=67%) and diastolic BP (-3.9 mm Hg, 95% CI: -5.1 to -2.8; I(2)=83%). The 95% PI ranged from -13.9 to -1.4 mm Hg for systolic BP and from -9.9 to +2.0 mm Hg for diastolic BP. The effect tended to be larger if the intervention was led by the pharmacist and was done at least monthly. CONCLUSIONS: Pharmacist interventions - alone or in collaboration with other healthcare professionals - improved BP management. Nevertheless, pharmacist interventions had differential effects on BP, from very large to modest or no effect; and determinants of heterogeneity could not be identified. Determining the most efficient, cost-effective, and least time-consuming intervention should be addressed with further research

Interdigital 50 nm Ti Electrode Arrays Fabricated Using XeF2 Enhanced Focused Ion Beam Etching

The fabrication of interdigitated titanium nanoelectrode arrays of 50 nm in width and spacing is described in this work. The nanoarrays have been realized using a Ga+ focused ion beam (FIB). FIB milling is typically accompanied by redeposition of removed material, which represents an important hindrance for milling closely spaced nanostructures. Redeposition effects have been reduced by means of XeF2 gas assistance, which increases the etch yield by a factor of seven compared with pure ion milling. Furthermore, we used a simple adsorption model, which led to the conclusion that dwell time and refresh time should be 30 ms, respectively, for optimized XeF2 assisted Ti milling. The measured resistance R of the electrodes is higher than 1 G ohm

Sodium intake and blood pressure in children with clinical conditions: A systematic review with meta-analysis.

Little is known on the effect of sodium intake on BP of children with clinical conditions. Our objective was therefore to review systematically studies that have assessed the association between sodium intake and BP in children with various clinical conditions. A systematic search of several databases was conducted and supplemented by a manual search of bibliographies and unpublished studies. Experimental and observational studies assessing the association between sodium intake and BP and involving children or adolescents between 0 and 18 years of age with any clinical condition were included. Out of the 6861 records identified, 51 full texts were reviewed, and 16 studies (10 experimental and 6 observational), involving overall 2902 children and adolescents, were included. Ten studies were conducted in children with elevated BP without identifiable cause, two in children with familial hypertension, one in children with at least one cardiovascular risk factor, one in children with chronic renal insufficiency, one in children with urolithiasis, and one in premature infants. A positive association between sodium intake and BP was found in all studies, except one. The meta-analysis of six studies among children with elevated BP without identifiable cause revealed a difference of 6.3 mm Hg (95% CI 2.9-9.6) and 3.5 mm Hg (95% CI 1.2-5.7) in systolic and diastolic BP, respectively, for every additional gram of sodium intake per day. In conclusion, our results indicate that the BP response to salt is greater in children with clinical conditions, mainly hypertension, than in those without associated clinical conditions

A systems approach towards remote health-monitoring in older adults: Introducing a zero-interaction digital exhaust.

Using connected sensing devices to remotely monitor health is a promising way to help transition healthcare from a rather reactive to a more precision medicine oriented proactive approach, which could be particularly relevant in the face of rapid population ageing and the challenges it poses to healthcare systems. Sensor derived digital measures of health, such as digital biomarkers or digital clinical outcome assessments, may be used to monitor health status or the risk of adverse events like falls. Current research around such digital measures has largely focused on exploring the use of few individual measures obtained through mobile devices. However, especially for long-term applications in older adults, this choice of technology may not be ideal and could further add to the digital divide. Moreover, large-scale systems biology approaches, like genomics, have already proven beneficial in precision medicine, making it plausible that the same could also hold for remote-health monitoring. In this context, we introduce and describe a zero-interaction digital exhaust: a set of 1268 digital measures that cover large parts of a person's activity, behavior and physiology. Making this approach more inclusive of older adults, we base this set entirely on contactless, zero-interaction sensing technologies. Applying the resulting digital exhaust to real-world data, we then demonstrate the possibility to create multiple ageing relevant digital clinical outcome assessments. Paired with modern machine learning, we find these assessments to be surprisingly powerful and often on-par with mobile approaches. Lastly, we highlight the possibility to discover novel digital biomarkers based on this large-scale approach