The Spot the Troll Quiz game increases accuracy in discerning between real and inauthentic social media accounts.

The proliferation of political mis/disinformation on social media has led many scholars to embrace "inoculation" techniques, where individuals are trained to identify the signs of low-veracity information prior to exposure. Coordinated information operations frequently spread mis/disinformation through inauthentic or "troll" accounts that appear to be trustworthy members to the targeted polity, as in Russia's attempts to influence the 2016 US presidential election. We experimentally tested the efficacy of inoculation against inauthentic online actors, using the Spot the Troll Quiz, a free, online educational tool that teaches how to spot markers of inauthenticity. Inoculation works in this setting. Across an online US nationally representative sample (N = 2,847), which also oversampled older adults, we find that taking the Spot the Troll Quiz (vs. playing a simple game) significantly increases participants' accuracy in identifying trolls among a set of Twitter accounts that are novel to participants. This inoculation also reduces participants' self-efficacy in identifying inauthentic accounts and reduced the perceived reliability of fake news headlines, although it had no effect on affective polarization. And while accuracy in the novel troll-spotting task is negatively associated with age and Republican party identification, the Quiz is equally effective on older adults and Republicans as it was on younger adults and Democrats. In the field, a convenience set of Twitter users who posted their Spot the Troll Quiz results in the fall of 2020 (N = 505) reduced their rate of retweeting in the period after the Quiz, with no impact on original tweeting.

Partial osmotic pressures of ions in electrolyte solutions and the Gibbs-Guggenheim uncertainty principle.

The concept of the partial osmotic pressure of ions in an electrolyte solution is critically examined. In principle these can be defined by introducing a solvent-permeable wall and measuring the force per unit area which can certainly be attributed to individual ions. Here I demonstrate that although the total wall force balances the bulk osmotic pressure as required by mechanical equilibrium, the individual partial osmotic pressures are extrathermodynamic quantities dependent on the electrical structure at the wall, and as such they resemble attempts to define individual ion activity coefficients. The limiting case where the wall is a barrier to only one species of ion is also considered, and with ions on both sides the classic Gibbs-Donnan membrane equilibrium is recovered, thus providing a unifying treatment. The analysis can be extended to illustrate how the electrical state of the bulk is affected by the nature of the walls and the container handling history, thus supporting the "Gibbs-Guggenheim uncertainty principle," namely the notion that the electrical state is unmeasurable and usually accidentally determined. Since this uncertainty is conferred also onto individual ion activities, it has implications for the current (2002) IUPAC definition of pH.

Can Machine Learning Predict the Phase Behavior of Surfactants?

We explore the prediction of surfactant phase behavior using state-of-the-art machine learning methods, using a data set for twenty-three nonionic surfactants. Most machine learning classifiers we tested are capable of filling in missing data in a partially complete data set. However, strong data bias and a lack of chemical space information generally lead to poorer results for entire de novo phase diagram prediction. Although some machine learning classifiers perform better than others, these observations are largely robust to the particular choice of algorithm. Finally, we explore how de novo phase diagram prediction can be improved by the inclusion of observations from state points sampled by an analogy to commonly used experimental protocols. Our results indicate what factors should be considered when preparing for machine learning prediction of surfactant phase behavior in future studies.

Phase Behavior of Alkyl Ethoxylate Surfactants in a Dissipative Particle Dynamics Model.

We present a dissipative particle dynamics (DPD) model capable of capturing the liquid state phase behavior of nonionic surfactants from the alkyl ethoxylate (CnEm) family. The model is based upon our recent work [Anderson et al. J. Chem. Phys. 2017, 147, 094503] but adopts tighter control of the molecular structure by setting the bond angles with guidance from molecular dynamics simulations. Changes to the geometry of the surfactants were shown to have little effect on the predicted micelle properties of sampled surfactants, or the water-octanol partition coefficients of small molecules, when compared to the original work. With these modifications the model is capable of reproducing the binary water-surfactant phase behavior of nine surfactants (C8E4, C8E5, C8E6, C10E4, C10E6, C10E8, C12E6, C12E8, and C12E12) with a good degree of accuracy.

Modeling Alkyl Aromatic Hydrocarbons with Dissipative Particle Dynamics.

Building on previous work studying alkanes, we develop a dissipative particle dynamics (DPD) model to capture the behavior of the alkyl aromatic hydrocarbon family under ambient conditions of 298 K and 1 atmosphere. Such materials are of significant worldwide industrial importance in applications such as solvents, chemical intermediates, surfactants, lubricating oils, hydraulic fluids, and greases. We model both liquids and waxy solids for molecules up to 36 carbons in size and demonstrate that we can correctly capture both the freezing transition and liquid-phase densities in pure substances and mixtures. We also demonstrate the importance of including specialized bead types into the DPD model (rather than solely relying on generic bead types) to capture specific local geometrical constructs such as the benzene ring found in the benzyl chemical group; this can be thought of as representing subtle real-world many-body effects via customized pairwise non-bonded potentials.

Traumatic inferior lumbar hernia.

Traumatic lumbar hernias are rare, with little surgical literature describing their management. In this we report about a 41-year-old patient admitted to University Hospital Southampton following a high velocity road traffic collision, of estimated speed 140 mph. He suffered multiple bony injuries, and a traumatic right inferior lumbar hernia containing the ascending colon. The hernia was surgically repaired extra-peritoneally with mesh and abdominal wall muscles approximated and sutured.

Systematic Parameterization of Ion-Surfactant Interactions in Dissipative Particle Dynamics Using Setschenow Coefficients.

Dissipative particle dynamics (DPD) simulations of nonionic surfactants with an added salt show that the Setschenow relationship is reproduced; that is, the critical micelle concentration is log-linearly dependent on the added salt concentration. The simulated Setschenow coefficients depend on the DPD bead-bead repulsion amplitudes, and matching to the experimentally determined values provides a systematic method to parameterize the interactions between salt ion beads and surfactant beads. The optimized ion-specific interaction parameters appear to be transferrable and follow the same trends as the empirical Hofmeister series.

Interhospital variability in localization techniques for small pulmonary nodules in children: A pediatric surgical oncology research collaborative study.

BACKGROUND: Pulmonary nodules that are deep within lung parenchyma and/or small in size can be challenging to localize for biopsy. This study describes current trends in performance of image-guided localization techniques for pulmonary nodules in pediatric patients. METHODS: A retrospective review was performed on patients < 21 years of age undergoing localization of pulmonary nodules at 15 institutions. Localization and resection success, time in interventional radiology (IR), operating room (OR) and total anesthesia time, complications, and technical problems were compared between techniques. RESULTS: 225 patients were included with an average of 1.3 lesions (range 1-5). Median nodule size and depth were 4 mm (range 0-30) and 5.4 mm (0-61), respectively. The most common localization techniques were: wire + methylene blue dye (MBD) (28%), MBD only (25%), wire only (14%), technetium-99 only (11%), coil + MBD (7%) and coil only (5%). Localization technique was associated with institution (p < 0.01); technique and institution were significantly associated with mean IR, OR, and anesthesia time (all p < 0.05). Comparing techniques, there was no difference in successful IR localization (range 92-100%, p = 0.75), successful resection (94-100%, p = 0.98), IR technical problems (p = 0.22), or operative complications (p = 0.16). CONCLUSIONS: Many IR localization techniques for small pulmonary nodules in children can be successful, but there is wide variability in application by institution and in procedure time. LEVEL OF EVIDENCE: Retrospective review, Level 3.

Diffusion, phase behavior, and gelation in a two-dimensional layer of colloids in osmotic equilibrium with a polymer reservoir.

The addition of enough non-adsorbing polymers to an otherwise stable colloidal suspension gives rise to a variety of phase behaviors and kinetic arrest due to the depletion attraction induced between the colloids by the polymers. We report a study of these phenomena in a two-dimensional layer of colloids. The three-dimensional phenomenology of crystal-fluid coexistence is reproduced, but gelation takes a novel form, in which the strands in the gel structure are locally crystalline. We compare our findings with a previous simulation and theory and find substantial agreement.

Using a Scenario-Based Approach to Teaching Professionalism to Medical Students: Course Description and Evaluation.

BACKGROUND: Doctors play a key role in individuals' lives undergoing a holistic integration into local communities. To maintain public trust, it is essential that professional values are upheld by both doctors and medical students. We aimed to ensure that students appreciated these professional obligations during the 3-year science-based, preclinical course with limited patient contact. OBJECTIVE: We developed a short scenario-based approach to teaching professionalism to first-year students undertaking a medical course with a 3-year science-based, preclinical component. We aimed to evaluate, both quantitatively and qualitatively, student perceptions of the experience and impact of the course. METHODS: An interactive professionalism course entitled Entry to the Profession was designed for preclinical first-year medical students. Two scenario-based sessions were created and evaluated using established professionalism guidance and expert consensus. Quantitative and qualitative feedback on course implementation and development of professionalism were gathered using Likert-type 5-point scales and debrief following course completion. RESULTS: A total of 70 students completed the Entry to the Profession course over a 2-year period. Feedback regarding session materials and logistics ranged from 4.16 (SD 0.93; appropriateness of scenarios) to 4.66 (SD 0.61; environment of sessions). Feedback pertaining to professionalism knowledge and behaviors ranged from 3.11 (SD 0.99; need for professionalism) to 4.78 (SD 0.42; relevance of professionalism). Qualitative feedback revealed that a small group format in a relaxed, open environment facilitated discussion of the major concepts of professionalism. CONCLUSIONS: Entry to the Profession employed an innovative approach to introducing first-year medical students to complex professionalism concepts. Future longitudinal investigations should aim to explore its impact at various stages of preclinical, clinical, and postgraduate training.

Critical Micelle Concentrations in Surfactant Mixtures and Blends by Simulation.

We explore the use of coarse-grained dissipative particle dynamics simulations to predict critical micelle concentrations (CMCs) in polydisperse surfactant mixtures and blends. By fitting pseudo-phase separation models (PSMs) to aqueous solutions of binary surfactant mixtures at selected compositions above the CMC, we avoid the need for expensive simulations of more complex multicomponent mixtures performed as a function of dilution. The approach is demonstrated for sodium laureth sulfate (SLES) surfactants with polydispersity in the ethoxylate spacer. For this system, we find a modest degree of cooperativity in micelle formation, which we attribute to the reduced repulsion between charged headgroups for surfactants with dissimilar ethoxylate spacer lengths. However, this is insufficient to explain the lowered CMC often observed in commercial SLES samples, which we attribute to the presence of small amounts of unsulfated alkyl ethoxylates and/or traces of salt.

Translation of Chemical Structure into Dissipative Particle Dynamics Parameters for Simulation of Surfactant Self-Assembly.

Dissipative particle dynamics (DPD) can be used to simulate the self-assembly properties of surfactants in aqueous solutions, but in order to simulate a new compound, a large number of new parameters are required. New methods for the calculation of reliable DPD parameters directly from chemical structure are described, allowing the DPD approach to be applied to a much wider range of organic compounds. The parameters required to describe the bonded interactions between DPD beads were calculated from molecular mechanics structures. The parameters required to describe the nonbonded interactions were calculated from surface site interaction point (SSIP) descriptions of molecular fragments that represent individual beads. The SSIPs were obtained from molecular electrostatic potential surfaces calculated using density functional theory and used in the SSIMPLE algorithm to calculate transfer free energies between different bead liquids. This approach was used to calculate DPD parameters for a range of different types of surfactants, which include ester, amide, and sugar moieties. The parameters were used to simulate the self-assembly properties in aqueous solutions, and comparison of the results for 27 surfactants with the available experimental data shows that these DPD simulations accurately predict critical micelle concentrations, aggregation numbers, and the shapes of the supramolecular assemblies formed. The methods described here provide a general approach to determining DPD parameters for neutral organic compounds of arbitrary structure.

Neonatal Anthropometric Measures and Peripherally Inserted Central Catheter Depth.

BACKGROUND: Peripherally inserted central catheters (PICCs) are used routinely in neonatal care. Measures of surface anatomy have been used to estimate appropriate PICC depth in neonates since 1973. However, prior PICC research using anthropometric measures to estimate proper PICC insertion depth has been limited to pediatric and adult literature. PURPOSE: The purpose of this study was to explore the relationships among a neonate's anthropometric measures and the appropriate PICC insertion depth. METHODS: Neonates requiring PICC insertion at Nationwide Children's Hospital were enrolled between January and September 2018. Standard PICC procedures were followed. The research group corroborated appropriate PICC tip position of enrolled infants. Multivariable linear regression with robust standard errors was used to evaluate linear relationships between PICC insertion depth and current weight, current length, and PICC insertion site. RESULTS: Demographics of enrolled infants included gestational ages of 23 to 39 weeks, weights of 510 to 3870 g, and lengths of 31 to 54 cm. Of the 56 infants considered, final statistical analysis included 49 neonates (14 ankle, 16 knee, and 19 antecubital insertions). Current neonatal weight was associated with PICC depth at all sites (all Ps < .0001). Current neonatal length was associated with PICC depth at all sites (all Ps < .0001). Preprocedure surface measurement was also strongly associated with PICC insertion depth (P < .0001). IMPLICATIONS FOR PRACTICE: This investigation demonstrated a relationship for both neonatal weight and length that may be an anthropometric model for neonatal PICC insertion depth. IMPLICATIONS FOR RESEARCH: A more robust sample size could more precisely define the anthropometric model.

Wax Formation in Linear and Branched Alkanes with Dissipative Particle Dynamics.

We present a dissipative particle dynamics (DPD) model for wax formation (i.e., the freezing transition) in linear and branched alkanes at room temperature (298 K) and atmospheric pressure. We parametrize the model using pure liquid phase densities and the onset of wax formation as a function of alkyl chain length. Significant emphasis is placed on building an accurate representation of the underlying molecular architecture by careful consideration of bond lengths and angles, aided by distributions obtained from molecular dynamics simulation. Using the derived model, we observe wax formation in n-alkanes when the alkyl chain length is greater than 18 (n-octadecane), in excellent agreement with experimental observations. Further, we reproduce the behavior of branched alkanes and mixtures including solubilities of heavy alkanes in light alkane solvents.

Non-Faradaic Electric Currents in the Nernst-Planck Equations and Nonlocal Diffusiophoresis of Suspended Colloids in Crossed Salt Gradients.

In the Nernst-Planck equations in two or more dimensions, a non-Faradaic solenoidal current can arise as a consequence of connecting patches with different liquid junction potentials. Whereas this current vanishes for binary electrolytes or in one-dimensional problems, it is in general nonvanishing, for example, in crossed salt gradients. For a suspended colloidal particle, chemiphoresis in the concentration gradients is generally vectorially misaligned with electrophoresis in the electrostatic potential gradient, and there is a nonlocal contribution to the latter deriving from the Ohmic electric field associated with the current; in a case study this contributes up to 20%-30% of the total effect.

A Surface Site Interaction Point Method for Dissipative Particle Dynamics Parametrization: Application to Alkyl Ethoxylate Surfactant Self-Assembly.

Dissipative particle dynamics (DPD) is a coarse-grained approach to the simulation of large supramolecular systems, but one limitation has been that the parameters required to describe the noncovalent interactions between beads are not readily accessible. A first-principles computational method has been developed so that bead interaction parameters can be calculated directly from ab initio gas-phase molecular electrostatic potential surfaces of the molecular fragments that represent the beads. A footprinting algorithm converts the molecular electrostatic potential surfaces into a discrete set of surface site interaction points (SSIPs), and these SSIPs are used in the SSIMPLE (surface site interaction model for the properties of liquids at equilibrium) algorithm to calculate the free energies of transfer of one bead into a solution of any other bead. The bead transfer free energies are then converted into the required DPD interaction parameters for all pairwise combinations of different beads. The reliability of the parameters was demonstrated using DPD simulations of a range of alkyl ethoxylate surfactants. The simulations reproduce the experimentally determined values of the critical micelle concentration and mean aggregation number well for all 22 surfactants studied.

Catheter-directed thrombolysis for submassive pulmonary embolism in children: A case series.

Incidence of venous thromboembolism, including pulmonary embolism (PE), continues to rise in children. Optimum management of submassive PE is unclear. The principal objective of this retrospective study was to investigate the radiological and clinical outcomes in children with submassive PE treated with catheter-directed thrombolysis (CDT). Five patients underwent six episodes of CDT. No patient developed major/clinically relevant non-major bleeding. Most patients had complete radiological thrombus resolution and no patient had evidence of chronic thromboembolic pulmonary hypertension. There is an urgent need for larger prospective cohort studies/randomized controlled trials to investigate the role of CDT in pediatric PE.