App-based COVID-19 syndromic surveillance and prediction of hospital admissions in COVID Symptom Study Sweden.

The app-based COVID Symptom Study was launched in Sweden in April 2020 to contribute to real-time COVID-19 surveillance. We enrolled 143,531 study participants (≥18 years) who contributed 10.6 million daily symptom reports between April 29, 2020 and February 10, 2021.

Quantum molecular dynamics of warm dense iron and a five-phase equation of state.

Through quantum molecular dynamics (QMD), utilizing both Kohn-Sham (orbital-based) and orbital-free density functional theory, we calculate the equation of state of warm dense iron in the density range 7-30g/cm^{3} and temperatures from 1 to 100 eV. A critical examination of the iron pseudopotential is made, from which we find a significant improvement at high pressure to the previous QMD calculations of Wang et al. [Phys.

Harnessing Nanotopography to Enhance Osseointegration of Clinical Orthopedic Titanium Implants-An and Analysis.

Despite technological advancements, further innovations in the field of orthopedics and bone regeneration are essential to meet the rising demands of an increasing aging population and associated issues of disease, injury and trauma. Nanotopography provides new opportunities for novel implant surface modifications and promises to deliver further improvements in implant performance. However, the technical complexities of nanotopography fabrication and surface analysis have precluded identification of the optimal surface features to trigger osteogenesis.

Ab initio Exchange-Correlation Free Energy of the Uniform Electron Gas at Warm Dense Matter Conditions.

In a recent Letter [T. Dornheim et al., Phys.

Why Do Irrelevant Alternatives Matter? An fMRI-TMS Study of Context-Dependent Preferences.

Both humans and animals are known to exhibit a violation of rationality known as "decoy effect": introducing an irrelevant option (a decoy) can influence choices among other (relevant) options. Exactly how and why decoys trigger this effect is not known. It may be an example of fast heuristic decision-making, which is adaptive in natural environments, but may lead to biased choices in certain markets or experiments.

pH Dependence of γ-Aminobutyric Acid Iontronic Transport.

The organic electronic ion pump (OEIP) has been developed as an "iontronic" tool for delivery of biological signaling compounds. OEIPs rely on electrophoretically "pumping" charged compounds, either at neutral or shifted pH, through an ion-selective channel. Significant shifts in pH lead to an abundance of H or OH, which are delivered along with the intended substance.

Gelatin freeze casting of biomimetic titanium alloy with anisotropic and gradient pore structure.

Titanium is a material commonly used for dental and orthopaedic implants. However, due to large differences in properties between the titanium metal and the natural bone, stress shielding has been observed in the surrounding area, resulting in bone atrophy, and thus has raised concerns of the use of this material. Ideally implant materials should possess similar properties to the surrounding tissues in order to distribute the load as the joint would naturally, while also possessing a similar porous structure to the bone to enable interaction with the surrounding material.

Osteogenic and bactericidal surfaces from hydrothermal titania nanowires on titanium substrates.

Nanotopographical cues on Ti have been shown to elicit different cell responses such as cell differentiation and selective growth. Bone remodelling is a constant process requiring specific cues for optimal bone growth and implant fixation. Moreover, biofilm formation and the resulting infection on surgical implants is a major issue.

Chemical delivery array with millisecond neurotransmitter release.

Technologies that restore or augment dysfunctional neural signaling represent a promising route to deeper understanding and new therapies for neurological disorders. Because of the chemical specificity and subsecond signaling of the nervous system, these technologies should be able to release specific neurotransmitters at specific locations with millisecond resolution. We have previously demonstrated an organic electronic lateral electrophoresis technology capable of precise delivery of charged compounds, such as neurotransmitters.

Ab Initio Quantum Monte Carlo Simulation of the Warm Dense Electron Gas in the Thermodynamic Limit.

We perform ab initio quantum Monte Carlo (QMC) simulations of the warm dense uniform electron gas in the thermodynamic limit. By combining QMC data with the linear response theory, we are able to remove finite-size errors from the potential energy over the substantial parts of the warm dense regime, overcoming the deficiencies of the existing finite-size corrections by Brown et al. [Phys.

Ionic Transport Coefficients of Dense Plasmas without Molecular Dynamics.

We present a theoretical model that allows a fast and accurate evaluation of ionic transport properties of realistic plasmas spanning from warm and dense to hot and dilute conditions, including mixtures. This is achieved by combining a recent kinetic theory based on effective interaction potentials with a model for the equilibrium radial density distribution based on an average atom model and the integral equations theory of fluids. The model should find broad use in applications where nonideal plasma conditions are traversed, including inertial confinement fusion, compact astrophysical objects, solar and extrasolar planets, and numerous present-day high energy density laboratory experiments.

Analysis of Osteoclastogenesis/Osteoblastogenesis on Nanotopographical Titania Surfaces.

A focus of orthopedic research is to improve osteointegration and outcomes of joint replacement. Material surface topography has been shown to alter cell adhesion, proliferation, and growth. The use of nanotopographical features to promote cell adhesion and bone formation is hoped to improve osteointegration and clinical outcomes.

Ionic and electronic transport properties in dense plasmas by orbital-free density functional theory.

We validate the application of our recent orbital-free density functional theory (DFT) approach [Phys. Rev. Lett.

Controlling epileptiform activity with organic electronic ion pumps.

In treating epilepsy, the ideal solution is to act at a seizure's onset, but only in the affected regions of the brain. Here, an organic electronic ion pump is demonstrated, which directly delivers on-demand pure molecules to specific brain regions. State-of-the-art organic devices and classical pharmacology are combined to control pathological activity in vitro, and the results are verified with electrophysiological recordings.

Mathematical modeling improves EC50 estimations from classical dose-response curves.

Unlabelled: The β-adrenergic response is impaired in failing hearts. When studying β-adrenergic function in vitro, the half-maximal effective concentration (EC50 ) is an important measure of ligand response. We previously measured the in vitro contraction force response of chicken heart tissue to increasing concentrations of adrenaline, and observed a decreasing response at high concentrations.

Cicada-inspired cell-instructive nanopatterned arrays.

Biocompatible surfaces hold key to a variety of biomedical problems that are directly related to the competition between host-tissue cell integration and bacterial colonisation. A saving solution to this is seen in the ability of cells to uniquely respond to physical cues on such surfaces thus prompting the search for cell-instructive nanoscale patterns. Here we introduce a generic rationale engineered into biocompatible, titanium, substrates to differentiate cell responses.

Scanning electron microscopical observation of an osteoblast/osteoclast co-culture on micropatterned orthopaedic ceramics.

In biomaterial engineering, the surface of an implant can influence cell differentiation, adhesion and affinity towards the implant. On contact with an implant, bone marrow-derived mesenchymal stromal cells demonstrate differentiation towards bone forming osteoblasts, which can improve osteointegration. The process of micropatterning has been shown to improve osteointegration in polymers, but there are few reports surrounding ceramics.

Fast and accurate quantum molecular dynamics of dense plasmas across temperature regimes.

We develop and implement a new quantum molecular dynamics approximation that allows fast and accurate simulations of dense plasmas from cold to hot conditions. The method is based on a carefully designed orbital-free implementation of density functional theory. The results for hydrogen and aluminum are in very good agreement with Kohn-Sham (orbital-based) density functional theory and path integral Monte Carlo calculations for microscopic features such as the electron density as well as the equation of state.

Investigation of the limits of nanoscale filopodial interactions.

Mesenchymal stem cells are sensitive to changes in feature height, order and spacing. We had previously noted that there was an inverse relationship between osteoinductive potential and feature height on 15-, 55- and 90 nm-high titania nanopillars, with 15 nm-high pillars being the most effective substrate at inducing osteogenesis of human mesenchymal stem cells. The osteoinductive effect was somewhat diminished by decreasing the feature height to 8 nm, however, which suggested that there was a cut-off point, potentially associated with a change in cell-nanofeature interactions.

Accurate homogeneous electron gas exchange-correlation free energy for local spin-density calculations.

An accurate analytical parametrization for the exchange-correlation free energy of the homogeneous electron gas, including interpolation for partial spin polarization, is derived via thermodynamic analysis of recent restricted path integral Monte Carlo (RPIMC) data. This parametrization constitutes the local spin density approximation (LSDA) for the exchange-correlation functional in density functional theory. The new finite-temperature LSDA reproduces the RPIMC data well, satisfies the correct high-density and low- and high-T asymptotic limits, and is well behaved beyond the range of the RPIMC data, suggestive of broad utility.

Embossing of micropatterned ceramics and their cellular response.

The aim of this work is to investigate the use of microtopographies in providing physical cues to modulate the cellular response of human mesenchymal stem cells on ceramics. Two microgrooved patterns (100 μm/50 μm, 10 μm/10 μm groove/pitch) were transcribed reversely onto alumina green ceramic tapes via an embossing technique followed by sintering. Characterization of the micropatterned alumina surfaces and their cellular response was carried out.

2D and 3D nanopatterning of titanium for enhancing osteoinduction of stem cells at implant surfaces.

The potential for the use of well-defined nanopatterns to control stem cell behaviour on surfaces has been well documented on polymeric substrates. In terms of translation to orthopaedic applications, there is a need to develop nanopatterning techniques for clinically relevant surfaces, such as the load-bearing material titanium (Ti). In this work, a novel nanopatterning method for Ti surfaces is demonstrated, using anodisation in combination with PS-b-P4VP block copolymer templates.

Titanium nanofeaturing for enhanced bioactivity of implanted orthopedic and dental devices.

Titanium (Ti) is used as a load-bearing material in the production of orthopedic devices. The clinical efficacy of these implants could be greatly enhanced by the addition of nanofeatures that would improve the bioactivity of the implants, in order to promote in situ osteo-induction and -conduction of the patient's stem and osteoprogenitor cells, and to enhance osseointegration between the implant and the surrounding bone. Nanofeaturing of Ti is also currently being applied as a tool for the biofunctionalization of commercially available dental implants.

Comparison of density functional approximations and the finite-temperature Hartree-Fock approximation in warm dense lithium.

We compare the behavior of the finite-temperature Hartree-Fock model with that of thermal density functional theory using both ground-state and temperature-dependent approximate exchange functionals. The test system is bcc Li in the temperature-density regime of warm dense matter (WDM). In this exchange-only case, there are significant qualitative differences in results from the three approaches.

Novel anodization technique using a block copolymer template for nanopatterning of titanium implant surfaces.

Precise surface nanopatterning is a promising route for predictable control of cellular behavior on biomedical materials. There is currently a gap in taking such precision engineered surfaces from the laboratory to clinically relevant implant materials such as titanium (Ti). In this work, anodization of Ti surfaces was performed in combination with block copolymer templates to create highly ordered and tunable oxide nanopatterns.