The US biomedical research workforce suffers from systemic barriers causing insufficient diversity and perpetuating inequity. To inform programming enhancing graduate program access, we implemented a formative mixed-method study to identify needed supports for program applications and graduate program success. Overall, results indicate value in added supports for understanding application needs, network development, critical thinking, time management, and reading academic/scientific literature. We find selected differences for underrepresented minority (URM) students compared to others, including in the value of psychosocial supports. This work can inform broader efforts to enhance graduate school access and provides foundation for further understanding of URM students’ experiences.

Apart from its role as a digestive and absorptive organ, the gastrointestinal (GI) tract is a vital immune organ that encompasses roughly 70 % of the total immune cells of the body. As such, the physical, chemical and nutrient composition of the diet influences overall GI function, effectively as an immune organ. With the improvement in feed technology, agro-industrial co-products that are high in fibre have been widely used as a feed ingredient in the diets of pigs and poultry. Arabinoxylan (AX) and mannan are the most abundant hemicellulosic polysaccharides present in cereal grain and co-product ingredients used in the livestock industry. When monogastric animals consume diets containing high amounts of AX and mannans, stimulation of GI immune cells may occur. This involves the activation of several cellular and molecular pathways of the immune system and requires a considerable amount of energy and nutrients to be expended by the animal, which may ultimately influence overall health and growth performance of animals. Therefore, a better understanding of the role of AX and mannan in immune modulation will be helpful in modulating untoward GI immune responses, thereby minimising nutrient and energy expenditure toward this effort. This review will summarise pertinent research on the role of oligosaccharides and polysaccharides containing AX and mannans in immune modulation in order to preserve gut integrity.

While SrTiO3 exhibits promising electronic transport properties, its high thermal conductivity (κ) is detrimental for its use as a thermoelectric material. Here, we investigate the influence of oxygen non-stoichiometry on κ in bulk SrTiO3 ceramics. A significant reduction in κ was achieved in oxygen deficient SrTiO3−δ, owing to the presence of oxygen vacancies that act as phonon scattering centers. Upon oxidation of SrTiO3−δ, the κ of pristine SrTiO3 was recovered, suggesting that oxygen vacancies were indeed responsible for the reduction in κ. Raman spectroscopy was used as an independent tool to confirm the reduction of oxygen vacancies in SrTiO3−δ upon oxidation.

In this investigation, a data-driven turbulence closure framework is introduced and deployed for the subgrid modelling of Kraichnan turbulence. The novelty of the proposed method lies in the fact that snapshots from high-fidelity numerical data are used to inform artificial neural networks for predicting the turbulence source term through localized grid-resolved information. In particular, our proposed methodology successfully establishes a map between inputs given by stencils of the vorticity and the streamfunction along with information from two well-known eddy-viscosity kernels. Through this we predict the subgrid vorticity forcing in a temporally and spatially dynamic fashion. Our study is both a priori and a posteriori in nature. In the former, we present an extensive hyper-parameter optimization analysis in addition to learning quantification through probability-density-function-based validation of subgrid predictions. In the latter, we analyse the performance of our framework for flow evolution in a classical decaying two-dimensional turbulence test case in the presence of errors related to temporal and spatial discretization. Statistical assessments in the form of angle-averaged kinetic energy spectra demonstrate the promise of the proposed methodology for subgrid quantity inference. In addition, it is also observed that some measure of a posteriori error must be considered during optimal model selection for greater accuracy. The results in this article thus represent a promising development in the formalization of a framework for generation of heuristic-free turbulence closures from data.

Relativistically hot electron–positron–ion (EPI) plasmas in the presence of relativistic intense electromagnetic (EM) radiation that are not in thermal equilibrium are studied by following a modified plasma particle distribution function. By means of a kinetic description, soliton solution is obtained for a small amplitude EM wave, whereas for large amplitude EM waves a cusp soliton solution is obtained. A general expression of positron density oscillations is obtained for long wavelength in comparison with the Debye length of electrons, and is discussed for special cases. Dispersion relations for a new type of longitudinal waves with slow damping is formulated as a consequence of resonant wave–particle interaction, and the necessary conditions for the existence of positron sound waves are obtained. Furthermore, for ultrarelativistic electrons and non-relativistic positrons, quasi positron sound waves dispersion relation in the intermediate wave range is obtained. It is shown that the modulation of amplitude of relativistic EM waves leads to instability for the rare plasma. Finally, we have obtained the relativistic kinetic nonlinear Schrödinger equation (KNLS) with local and non-local nonlinearities. The KNLS equation depicts nonlinear Landau damping rates for intense EM waves, and these damping rates are also examined.

Arbitrary amplitude and small amplitude ion-acoustic solitary waves (IASWs) have been investigated in a relativistic, collisionless, unmagnetized, and degenerate dense electron–positron–ion plasma. The arbitrary amplitude IASWs have been studied by using the Sagdeev-type pseudo-potential approach. Along with approximate solution, the exact amplitude solitary structure has also been studied numerically. The electrons and positrons are assumed to follow the corresponding Fermi distribution function and the ions are described by the hydrodynamic equations. A new dispersion relation for the ion-acoustic wave has been derived for the relativistic Thomas–Fermi plasma. An energy balance-like equation involving the Sagdeev-type pseudo-potential has been investigated and it has been shown that the concentration of plasma particles has significant effect on the permitted Mach number range of IASWs. Also, it has been pointed out that the only compressional supersonic IASWs can propagate in the relativistic Thomas–Fermi plasma. The present work would be helpful to understand the excitation of the nonlinear ion-acoustic waves in a degenerate plasma, such as in superdense white dwarfs and in the cores of massive planets.

The majority of arrhythmias presenting in infancy cardiovert readily or rapidly respond to conventional medical therapy. A small number prove highly refractory to anti-arrhythmic medications. Myocardial performance may be severely compromised by the combination of fast heart rate and negatively inotropic drugs. Some babies die. We have recently supported 2 babies with refractory arrhythmias on ECMO, both to pursue drug therapy and eventually, to support the circulation during radiofrequency ablation, with very successful results. The first patient was a 2.5 kg neonate presenting with collapse secondary to atrial ectopic tachycardia with a rate of 300/minute. Myocardial function was severely impaired. The arrhythmia was adenosine resistant and after iv amiodarone loading had no effect, esmolol infusion was started. This produced profound hypotension and the arrhythmia rapidly recommenced after DC cardioversion. In the face of such severe haemodynamic disturbance, VA ECMO was instituted. Further anti-arrhythmics were tried on-circulatory support, but the arrhythmia was incessant despite multiple DC cardioversions. Therefore radiofrequency ablation of the atrial ectopic focus was attempted on ECMO support. This was achieved uneventfully and the myocardial function rapidly improved, with decannulation 24 hours later. Unfortunately the arrhythmia recurred 2 weeks later, but was successfully treated by further ablation without ECMO. The child remains well with normal development on no medication. An 11-month-old baby presented to the GP with acute onset of lethargy and poor feeding and a heart rate of 350 bpm was noted! This was a broad complex tachycardia with independent p wave activity (confirmed with adenosine); ie ventricular tachycardia. Although initially well tolerated, the tachycardia resisted DC “cardioversion” even up to 60 J. Progressive and severe myocardial dysfunction and hypotension ensued, exacerbated by any attempts at drug therapy. The patient was therefore placed on VA ECMO. Some slowing of the ventricular rhythm was achieved with amiodarone and flecainide. The patient was then decannulated but the rapid arrhythmia recurred and ECMO was reinstituted. Electro-physiological mapping was then undertaken on ECMO support. NAVEX mapping identified a right ventricular outflow tract focus. This was resistant to conventional RF energy but was eventually successfully ablated with a “Cool-tip” catheter. Myocardial function improved rapidly, the patient was decannulated after 48 hours observation and there has been no recurrence of the arrhythmia since discharge. Although viewed as a very invasive technique, VA ECMO support here has prevented two otherwise unavoidable deaths in babies with conditions readily treated by radio-frequency techniques in older children. Not only did ECMO permit institution of aggressive drug therapy but also safely supported catheter interventions in very small patients. ECMO support should be considered early for small patients with refractory arrhythmias, before irreversible neurological compromise ensues. It could also be used electively to permit radiofrequency ablation in children whose size causes concern for safe catheter manipulation.

We have developed an empirical method to model bioresponse to the surfaces of biodegradable polymers in a combinatorial library using Artificial Neural Networks (ANN) in conjunction with molecular modeling and machine learning methodology. We validated the procedure by modeling human fibrinogen adsorption to 22 structurally distinct polymers. Subsequently, the method was used to model the more complicated phenomena of rat lung fibroblast and normal human fetal foreskin fibroblast proliferation in the presence of 24 and 44 different polymers, respectively. In each case, the root mean square (rms) percent error of the prediction was substantially less than the experimental variation, showing that the models can distinguish high and low performing polymers based on structure/property information. Using this method to screen candidate materials in terms of specific bioresponse prior to extensive experimental testing will greatly facilitate materials development for biomedical applications.