Sepiolite, a fibrous clay mineral, shows superior salt tolerance compared with layered clays, making it attractive for seawater-based drilling fluids. However, the specific ions responsible for rheological degradation in complex seawater environments remain unclear. The present study used a component-resolved approach to investigate the effects of five major seawater salts: NaCl, MgCl2, Na2SO4, CaCl2, and KCl, on the microstructure and rheology of 5 wt.% sepiolite dispersions. Zeta-potential measurements, cryogenic scanning electron microscopy (Cryo-SEM), and rheological tests revealed distinct ion-specific effects. Monovalent cations, Na+ and K+, mainly compressed the electrical double layer (EDL) and preserved relatively voluminous, reversible fiber networks, resulting in modest viscosity loss. In contrast, divalent cations, Mg2+ and Ca2+, caused stronger charge neutralization, probably through a combination of EDL compression and specific cation association with sepiolite surfaces, thereby promoting side-by-side fiber aggregation into bundles. This bundling reduced the number of effectively dispersed structural units and lowered the apparent aspect ratio, leading to pronounced apparent-viscosity reductions of 40% for MgCl2 and 27% for CaCl2. Mg2+ reduced the zeta potential to a near-neutral or slightly positive value (+0.20 mV). Although MgCl2 accounted for only 23% of the ionic strength of the simplified seawater system, its strong interfacial effect was closely associated with fiber bundling and rheological deterioration. The apparent viscosity in seawater (5.0 mPa·s) was closer to that in the divalent-cation systems than to a simple average of all single-salt systems, indicating that minority divalent cations exert a disproportionate influence on rheological degradation. These findings provide mechanistic guidance for optimizing sepiolite-based drilling fluids in high-salinity environments.

Phosphate in the form of organic compounds can be bound in soils containing the aluminosilicate allophane. A significant part of this phosphorus is believed to be present as nucleic acids. The interaction of yeast RNA with allophane was studied to further the understanding of the allophane/organic macro molecule interaction as well as the binding of organic phosphorus by allophanic soils. The extent of RNA adsorption on the allophane was dependent upon the pH, the charge and concentration of simple cations, the concentration of RNA, and the time of interaction. From a mixture containing 145 mg/liter RNA and 2.9 g/liter allophane in 10−2 M NaCl, the amount of RNA adsorbed increased from 6% at pH 10 to 98% at pH 3. The adsorption also increased as the concentration of added NaCl was increased from 10−4 M to 10−1 M, but only when the pH was greater than 5, i.e., above the isoelectric point of the clay. Mg2+ and Ca2+ were equally much more effective at promoting adsorption than Na+ at the same concentrations. There was no difference in the effectiveness of SO4−2, Cl−, or NO3− at pH 5 or higher. The adsorption isotherm at pH 7 can be described by the Langmuir equation; the apparent adsorption maximum was 38 mg/g. Van der Waals and simple electrostatic forces appear to dominate the interaction leading to the adsorption of RNA by allophane.

Three ball clays (SP from England, TSMA from France and UK from the Ukraine) were characterized for their dry and wet colloidal properties. On the basis of X-ray diffraction and chemical analyses the clays were classified as kaolinite-rich clay, smectitic kaolinite-rich clay and illitic kaolinite-rich clay. The ζ (zeta) potential at the clay-water interface as a function of pH, in three different electrolytes, was investigated using an electroacoustic technique. Starting from measurements of dynamic mobility, the calculated ζ potential was found to be almost constant as a function of pH for the TSMA and UK clays, while it increased from −20 to −60 for the SP clay, when potassium nitrate was used as an electrolyte. The behavior of the three clays in calcium and magnesium nitrate was slightly different: SP showed a smaller increase in ζ potential, while a small deviation from the constant behavior of the UK clay was found. The results are explained in terms of the surrounding-ion atmosphere in light of the chemical-physical properties measured. Our results may well be of use to those involved in ceramic processing.

The purpose of this chronoepidemiologic study was to investigate the time-relationships between the yearly variations in occurrence of violent suicide in Belgium and the yearly variations in various biochemical, metabolic and immune variables in the Belgian population. The weekly mean number of deaths due to violent suicide for all of Belgium for the period 1979–1987 was computed. Twenty-six normal volunteers had monthly blood samplings during one calendar year for assays of plasma L-tryptophan (L-TRP), competing amino acids (CAA), and melatonin levels, maximal [3H]paroxetine binding to platelets, serum total cholesterol, calcium, magnesium, and soluble interleukin-2 receptor concentrations, and number of CD4+ T, CD8+ T and CD20+ B lymphocytes. The annual rhythm in violent suicide rate is highly significantly synchronized with the annual rhythms in L-TRP, [3H]paroxetine binding, cholesterol, calcium, magnesium, CD20+ B cells, and CD4+/CD8+ ratio; the mean peak (violent suicide, [3H]paroxetine binding) or nadir (all other variables) occurs around 3 May. There were significant inverse time-relationships between the time series of violent suicide rate and L-TRP, L-TRP/CAA ratio, total cholesterol, calcium and magnesium, CD4+/CD8+ T cell ratio and number of CD20+ B cells. Maximal [3H]paroxetine binding to platelets was significantly and positively related to the time series of violent suicide. An important part (56.4%) of the variance in mean weekly number of violent suicide rate was explained by the time series of L-TRP, cholesterol and melatonin.

Introduction: With rising health care costs impairing access to care, the judicious use of diagnostic tests has become a critical issue for most jurisdictions. Among tests regularly performed in the emergency department (ED), calcium (Ca), magnesium (Mg) and phosphorus (P) laboratory testing represents an annual expenditure of more than $4 million for the Québec health care system. We then sought to determine the best indications for ordering these serum levels by identifying patient risk factors predicting abnormal results. Methods: We are conducting a retrospective cohort study in two academic hospitals of Québec City, one providing acute general care and the other providing specialized care to oncologic and nephrologic patients. We included 1000 patients who had serum Ca and/or Mg and/or P levels prescribed by an emergency physician between January 1st 2016 and May 1st 2016. We are collecting demographic (e.g. age) and clinical (e.g. comorbidities) characteristics identified from literature review as potential explanatory variables of an abnormal serum level. Predictive models of a positive test result will be derived from logistic regressions. Results: We have evaluated 143 patients. ED prevalence rates of hypo- and hyper-calcemia (10.1% and 4,3%), hypo- and hyper-magnesemia (13.0% and 7,2%), hypo- and hyper-phosphatemia (9.5% and 13,9%) were similar to those reported in literature. Preliminary bivariate analysis (p<0.05) have shown that, for patients who had serum Ca/Mg/P levels prescribed, one in four complained of weakness, one in five complained of abdominal pain and one in five presented on physical examination an abnormal mental status. Acute and chronic renal failure appears to be a strong predictor of anomalies of any of those electrolytes. Neoplasia, metastasis, hallucinations, bone pain and confusion are more specifically associated with hypercalcemia. Use of corticosteroids is associated with hypocalcemia. Conclusion: Our bivariate analyses have identified potential risk factors of abnormal Ca/Mg/P results. Multivariate logistic regressions will be conducted on the complete planned cohort to further test these preliminary results.

Introduction: In the Emergency Department (ED), increasing time pressures and acuity require physicians to have access to quick and reliable data to guide patient care decisions. Blood gases (BGs) allow quick access to key information, and are used frequently in the ED. Our objective was to review the literature on reliability and accuracy of electrolyte measurements obtained from BGs in high acuity settings. Methods: A comprehensive literature review was conducted in September of 2015. The search strategy, done in conjunction with a medical librarian, identified studies that assessed the accuracy of BGs when compared to traditional laboratory serum measurements. Prior to the review we determined sodium and potassium would be the area of focus. Eligibility parameters for the studies included samples from acute care areas - the ED and ICU - and a comparison of BG and serum values taken simultaneously from the patient. Results: Our review included 12 studies, 9 in adult and 3 in pediatrics. There were approximately 1,135 patients included, consisting of 851 adult and 284 pediatric cases. The results were mixed; 9 studies agreed that sodium and potassium readings from BGs were accurate enough to guide acute care decisions, 5 did not. Furthermore, important questions were raised regarding the varying accuracy of BGs depending on what physiological level the electrolytes were at during the time of collection, i.e. at critical vs non-critical levels. Conclusion: This is the first literature review to examine the existing evidence on the accuracy of BGs in acute care environments. Given the variability in the results, a larger study needs to be done to determine the validity and reliability of blood gases for electrolytes in acute care settings. Only by ensuring the accuracy of data collected via point-of-care BGs can the most informed decisions be made surrounding patient care in acute care settings.

This study investigated four electrolytes (tap water, mineral water, seawater, and Al2O3 nanoparticles emulsified in deionized water) to prepare nanofluids for enhancing their microgeneration and heattransfer capabilities by conducting thermoelectric performance experiments on power generation facilities. This study first performed a two-step synthesis process by using emulsion-ultrasonic technology for fabricating an Al2O3 nanofluid to determine the optimal suspended stability for the alumina nanofluid used as an electrolyte according to the Zeta potential, pH value, thermal conductivity, and viscosity. The alumina nanofluid was then compared with the other aqueous solutions to determine the characteristics of the effects of the output currents, voltages, resistances, and temperature distributions at different operating temperatures, distances, and electrode areas. Finally, the emulsifying effect of the alumina nanofluid between 0 wt % and 2 wt % demonstrated the most favorable stability, particle fraction, thermal conductivity, and stable current output.