Further Exploration of Heat of Immersion as a Method to Quantify Wettability for Particulates: Effect of Temperature.

A previous paper [Weston et al. Ind. Eng. Chem. Res. 2015, 54, 4274-4284] by our group concluded that to distinguish between the wettability of different particles, heat of immersion is the best method, as opposed to the Washburn or sessile drop method. In this paper, heats of immersion of three different particles with three different wettabilities are measured at different temperatures to examine one critical assumption concerning the temperature dependence of the heat of immersion. In addition, surfactants are added to the water, and the effect of surfactant concentration on the heat of immersion is measured. One particularly noteworthy aspect of the current study is that some measurements were made at temperatures greater than 100 °C and hence pressures higher than atmospheric pressure with no more difficulty than measurements made at atmospheric pressure. The previous paper showed that, for certain particles, the relationship used by us and others between the heat of immersion and contact angle gave impossible values for certain surfaces. In this paper, the derivation of that expression is reexamined, and certain assumptions are highlighted. Because of issues with the assumptions, we agree with the conclusion from our previous paper that using the heat of immersion as a qualitative measure of wetting is appropriate. However, without measurement of the values of the liquid-solid interfacial energy with temperature as well as the gas-solid interfacial energy with temperature, conversion to the contact angle directly is not appropriate. However, for the same surface, using this approach to quantify the contact angle as a function of temperature is likely appropriate if the contact angle is measured using some other method at one temperature, at least over the limited temperature range (up to 150 °C) explored in this study.

[Low muscular mass and ketoacidosis]. / Lage spiermassa en een ketoacidose.

Fasting ketoacidosis is especially an underdiagnosed problem in patients with neuro-muscular disease with severely depleted muscular mass. During periods of prolonged fasting, low levels of insulin and high levels of glucagon induce lipolysis in the peripheral fat tissue. This will result in elevated free fatty acids levels in de blood and increased ketogenesis in the liver. These ketones pass into the blood, leading to a ketoacidosis. Patients with low muscular mass are more susceptible to develop ketoacidosis due to lower energy reserves and reduced glycogen stores on the one hand, and a reduced uptake of ketones by their low muscular mass on the other hand. During periods of increased metabolism and in the absence of adequate caloric intake, this can easily lead to severe ketoacidosis. An adequate oral caloric intake is essential in the prevention and treatment of fasting ketoacidosis.

BMI, male sex and IL28B genotype associated with persistently high hepatitis C virus RNA levels among chronically infected drug users up to 23 years following seroconversion.

The natural course of serum HCV RNA levels during chronic infection remains unclear. We investigated HCV RNA levels and factors associated with HCV RNA levels for the entire course from HCV seroconversion. We measured HCV RNA levels of 54 HCV seroconverters from the Amsterdam Cohort Studies among drug users at yearly intervals up to 23 years using bDNA (VERSANT 3.0, lower limit of detection 615 IU/mL). Samples below the cut-off of the assay were tested by TMA (Siemens VERSANT, detection limit 5 IU/mL). We used a latent class linear mixed model to examine the HCV RNA patterns and factors associated with HCV RNA levels. The median follow-up time was 10.8 years (IQR 6.5-14.9). We found two distinct HCV RNA patterns characterized by 45/54 cases and 9/54 cases. In multivariable analyses, HCV RNA levels were 0.41 log(10) IU/mL (95% confidence interval (CI) 0.06-0.75) higher for males as compared to females. Individuals with the IL28B CC genotype had 0.40 log(10) IU/mL (95% 0.08-0.73) higher HCV RNA levels than individuals with IL28B CT/TT genotypes. Body mass index (BMI) was associated with higher HCV RNA levels, 0.055 log(10) IU/mL per BMI point (95% CI 0.027-0.083). In this unique study, which examines the HCV RNA patterns over an extended period and following seroconversion, male sex, IL28B CC genotype and BMI were independently associated with higher average HCV RNA levels. These results contribute to defining the natural history of HCV infection and could play an important part in clinical decision-making.

Pseudosolid, shear-thinning gel formation in binary dispersions of metal oxide nanoparticles at low volume fractions.

Hydroxyl groups on the surface of metal oxide nanoparticles (nps) can be protonated or deprotonated depending on solution pH, changing both the magnitude and sign of the nps' surface charge. Binary mixtures of fumed metal oxide nps, dispersed in water at a solution pH where one species is positively charged and the other is negatively charged, form pseudosolid gels at volume fractions as low as 1.5 vol %. This work maps out regions of gel formation for binary mixtures of silica and alumina nps, silica and titania nps, and alumina and titania nps. The microscopic structure of these gels is investigated using transmission electron microscopy (TEM), small-angle x-ray scattering (SAXS), acoustic spectroscopy, and light microscopy.