Is detection of disease-modifying osteoarthritis drug treatment more effective when performing cartilage morphometry without blinding to MR image acquisition order?

OBJECTIVE: We here explore whether observed treatment effects of a putative disease-modifying osteoarthritis drug (DMOAD) are greater when cartilage morphometry is performed with rather than without knowledge of magnetic resonance imaging (MRI) acquisition order (unblinded/blinded to time point). METHODS: In the FORWARD (FGF-18 Osteoarthritis Randomized Controlled Trial with Administration of Repeated Doses) randomized controlled trial, 549 knee osteoarthritis patients were randomized 1:1:1:1:1 to three once-weekly intra-articular injections of placebo, 30 µg sprifermin every 6 or 12 months (M), or 100 µg every 6/12 M. After year 2, cartilage segmentation of BL through 24 M MRIs was performed, with blinding to acquisition order. After year 5, 24 and 60 M MRIs were analyzed together, with unknown relative order, but with segmented BL images as reference (24 M unblinded vs. BL), by the same operators. Total femorotibial joint cartilage thickness (TFTJ_ThC) change was obtained for 352 participants analyzed under both conditions. RESULTS: Twenty-four-month data read unblinded to order revealed a -35 ± 44 µm lower TFTJ_ThC than blinded analysis (all groups: lower/upper bounds -120/+51 µm; correlation r2 = 97%). With unblinded analysis, the placebo group lost -46 ± 57 µm TFTJ_ThC over 24 M, whereas 100 µg/every 6 M lost -2.2 ± 73 µm (difference =44 µm [95% CI: 22, 66]). With blinded analysis, placebo lost -11 ± 53 µm, whereas 100 µg/every 6 M gained 30 ± 62 µm (difference = 40 µm [95% CI: 21, 60]). 100 µg sprifermin injected every 6 M showed statistically significant (p < 0.001) treatment effects on TFTJ_ThC, with Cohen D = -0.66 for unblinded and D = -0.69 for blinded analysis. CONCLUSIONS: These results do not reveal that detection of proposed DMOAD treatment is enhanced with MRIs read unblinded to order; rather, the sensitivity is similar to blinded analysis. Choices on blinded vs. unblinded analysis may thus be based on other criteria.

Developing and evaluating a major trauma course and coaching programme for ward nurses.

Nurses working with major trauma patients in ward environments in the UK are expected to evidence their knowledge and skills in a set of national competencies. This article describes a bespoke major trauma course and a coaching and portfolio development programme designed to enhance ward nurses' knowledge and skills, help them evidence their competence and support their professional development. Evaluation of the course showed an overall improvement in nurses' self-rated competence and confidence in a range of relevant major trauma topics and clinical skills. Evaluation of the coaching and portfolio development programme showed that nurses believed their knowledge and skills had improved after taking part and that they valued the opportunity for professional development.

The cost-effectiveness, of pegcetacoplan compared with ravulizumab for the treatment of paroxysmal nocturnal hemoglobinuria, in a UK setting.

Aim: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare blood disorder characterized by hemolytic anemia, bone marrow failure and thrombosis. We evaluated, the cost-effectiveness of pegcetacoplan, a novel proximal C3 inhibitor, versus ravulizumab in patients with PNH and hemoglobin levels <10.5 g/dl despite eculizumab treatment in the UK healthcare and social services setting. Materials & methods: A Markov cohort framework model, based on the data from the pivotal trial of pegcetacoplan (PEGASUS/NCT03500549), evaluated lifetime costs and outcomes. Patients transitioned through 3 PNH hemoglobin level/red blood cell transfusion health states. Results: Pegcetacoplan provides lower lifetime costs/greater quality-adjusted life years (£6,409,166/14.694QALYs, respectively) versus ravulizumab (£6,660,676/12.942QALYs). Conclusion: Pegcetacoplan is associated with enhanced anemia control, greater QALYs and reduced healthcare costs versus ravulizumab in the UK healthcare and social services setting.

Discovery of a novel class of inhaled dual pharmacology muscarinic antagonist and ß2 agonist (MABA) for the treatment of chronic obstructive pulmonary disease (COPD).

The targeting of both the muscarinic and ß-adrenergic pathways is a well validated therapeutic approach for the treatment of chronic obstructive pulmonary disease (COPD). In this communication we report our effort to incorporate two pharmacologies into a single chemical entity, whose characteristic must be suitable for a once daily inhaled administration. Contextually, we aimed at a locally acting therapy with limited systemic absorption to minimize side effects. Our lung-tailored design of bifunctional compounds that combine the muscarinic and ß-adrenergic pharmacologies by the elaboration of the muscarinic inhibitor 7, successfully led to the potent, pharmacologically balanced muscarinic antagonist and ß2 agonist (MABA) 13.

Budget Impact Analysis of Gemtuzumab Ozogamicin for the Treatment of CD33-Positive Acute Myeloid Leukemia.

BACKGROUND: Gemtuzumab ozogamicin (GO) was approved in 2017 in the US for the treatment of adults with newly diagnosed CD33-positive (CD33+) acute myeloid leukemia (AML), and adults and pediatric patients with CD33+ relapsed/refractory (R/R) AML. OBJECTIVE: The aim of this study was to estimate the budgetary impact of introducing GO to a 1-million-member US health plan over a 5-year period. METHODS: We developed models to estimate the impact of introducing GO in combination with conventional induction chemotherapy or as monotherapy for newly diagnosed AML, and as monotherapy for R/R AML. Models were built using data on drug costs and treatment-related outcomes obtained from published clinical trials and other publicly available sources. Results were reported on a per member/per year and per member/per month (PMPM) basis. RESULTS: Base-case results of the newly diagnosed model indicated that the addition of GO in the combination setting reduced the overall budget of a 1-million-member health plan. The estimated net cost (US$) savings ranged from $72,969 ($0.006 PMPM) in year 1 to $745,426 ($0.062 PMPM) in year 5. In the monotherapy setting, GO was associated with increased net costs ranging from $4118 (0.0003 PMPM) in year 1 to $31,885 ($0.003 PMPM) in year 5. Base-case results of the R/R AML model demonstrated increased net costs that ranged from $17,326 ($0.001 PMPM) in year 1 to $46,163 ($0.004 PMPM) in year 5. Scenario analyses in all settings indicated the budget impact was not overly sensitive to the selected input assumptions, with the exception of the scenario considering only the pharmacy budget impact in the combination setting. CONCLUSIONS: The introduction of GO for newly diagnosed and R/R AML would have a minimal impact on the budget of a US health plan and could result in cost savings in the combination therapy setting for newly diagnosed AML.

Many-Body Interactions in Ice.

Many-body effects in ice are investigated through a systematic analysis of the lattice energies of several proton ordered and disordered phases, which are calculated with different flexible water models, ranging from pairwise additive (q-TIP4P/F) to polarizable (TTM3-F and AMOEBA) and explicit many-body (MB-pol) potential energy functions. Comparisons with available experimental and diffusion Monte Carlo data emphasize the importance of an accurate description of the individual terms of the many-body expansion of the interaction energy between water molecules for the correct prediction of the energy ordering of the ice phases. Further analysis of the MB-pol results, in terms of fundamental energy contributions, demonstrates that the differences in lattice energies between different ice phases are sensitively dependent on the subtle balance between short-range two-body and three-body interactions, many-body induction, and dispersion energy. By correctly reproducing many-body effects at both short range and long range, it is found that MB-pol accurately predicts the energetics of different ice phases, which provides further support for the accuracy of MB-pol in representing the properties of water from the gas to the condensed phase.

Communication: Improved ab initio molecular dynamics by minimally biasing with experimental data.

Accounting for electrons and nuclei simultaneously is a powerful capability of ab initio molecular dynamics (AIMD). However, AIMD is often unable to accurately reproduce properties of systems such as water due to inaccuracies in the underlying electronic density functionals. This shortcoming is often addressed by added empirical corrections and/or increasing the simulation temperature. We present here a maximum-entropy approach to directly incorporate limited experimental data via a minimal bias. Biased AIMD simulations of water and an excess proton in water are shown to give significantly improved properties both for observables which were biased to match experimental data and for unbiased observables. This approach also yields new physical insight into inaccuracies in the underlying density functional theory as utilized in the unbiased AIMD.

On the accuracy of the MB-pol many-body potential for water: Interaction energies, vibrational frequencies, and classical thermodynamic and dynamical properties from clusters to liquid water and ice.

The MB-pol many-body potential has recently emerged as an accurate molecular model for water simulations from the gas to the condensed phase. In this study, the accuracy of MB-pol is systematically assessed across the three phases of water through extensive comparisons with experimental data and high-level ab initio calculations. Individual many-body contributions to the interaction energies as well as vibrational spectra of water clusters calculated with MB-pol are in excellent agreement with reference data obtained at the coupled cluster level. Several structural, thermodynamic, and dynamical properties of the liquid phase at atmospheric pressure are investigated through classical molecular dynamics simulations as a function of temperature. The structural properties of the liquid phase are in nearly quantitative agreement with X-ray diffraction data available over the temperature range from 268 to 368 K. The analysis of other thermodynamic and dynamical quantities emphasizes the importance of explicitly including nuclear quantum effects in the simulations, especially at low temperature, for a physically correct description of the properties of liquid water. Furthermore, both densities and lattice energies of several ice phases are also correctly reproduced by MB-pol. Following a recent study of DFT models for water, a score is assigned to each computed property, which demonstrates the high and, in many respects, unprecedented accuracy of MB-pol in representing all three phases of water.

First-Principles Monte Carlo Simulations of Reaction Equilibria in Compressed Vapors.

Predictive modeling of reaction equilibria presents one of the grand challenges in the field of molecular simulation. Difficulties in the study of such systems arise from the need (i) to accurately model both strong, short-ranged interactions leading to the formation of chemical bonds and weak interactions arising from the environment, and (ii) to sample the range of time scales involving frequent molecular collisions, slow diffusion, and infrequent reactive events. Here we present a novel reactive first-principles Monte Carlo (RxFPMC) approach that allows for investigation of reaction equilibria without the need to prespecify a set of chemical reactions and their ideal-gas equilibrium constants. We apply RxFPMC to investigate a nitrogen/oxygen mixture at T = 3000 K and p = 30 GPa, i.e., conditions that are present in atmospheric lightning strikes and explosions. The RxFPMC simulations show that the solvation environment leads to a significantly enhanced NO concentration that reaches a maximum when oxygen is present in slight excess. In addition, the RxFPMC simulations indicate the formation of NO2 and N2O in mole fractions approaching 1%, whereas N3 and O3 are not observed. The equilibrium distributions obtained from the RxFPMC simulations agree well with those from a thermochemical computer code parametrized to experimental data.

Hydroxide Solvation and Transport in Anion Exchange Membranes.

Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.

Tramadol and the risk of fracture in an elderly female population: a cost utility assessment with comparison to transdermal buprenorphine.

INTRODUCTION: Opioid treatment for chronic pain is a known risk factor for falls and/or fractures in elderly patients. The latter cause a significant cost to the National Health Service and the Personal Social Services in the UK. Tramadol has a higher risk of fractures than some other opioid analgesics used to treat moderate-to-severe pain and, in the model described here, we investigate the cost effectiveness of transdermal buprenorphine treatment compared with tramadol in a high-risk population. METHODS: A model was developed to assess the cost effectiveness of tramadol compared with transdermal buprenorphine over a 1-year time horizon and a patient population of high-risk patients (female patients age 75 or older). To estimate the total cost and quality-adjusted life years (QALYs) of treatment, published odds ratios are used in combination with the published incidence rates of four types of fracture: hip, wrist, humerus and other. RESULTS: The model shows tramadol to be associated with 1,058 more fractures per 100,000 patients per year compared with transdermal buprenorphine, resulting in transdermal buprenorphine being cost-effective with an incremental cost-effectiveness ratio of less than £7,000 compared with tramadol. Sensitivity analysis found this result to be robust. LIMITATIONS: In the UK data, there is uncertainty regarding the transdermal buprenorphine odds ratios for fractures. Odds ratios published in Danish and Swedish studies show similar point estimates but are associated with less uncertainty. CONCLUSION: Transdermal buprenorphine is cost-effective compared to tramadol at a willingness-to-pay threshold of £20,000 per QALY.

Discovery of optimal zeolites for challenging separations and chemical transformations using predictive materials modeling.

Zeolites play numerous important roles in modern petroleum refineries and have the potential to advance the production of fuels and chemical feedstocks from renewable resources. The performance of a zeolite as separation medium and catalyst depends on its framework structure. To date, 213 framework types have been synthesized and >330,000 thermodynamically accessible zeolite structures have been predicted. Hence, identification of optimal zeolites for a given application from the large pool of candidate structures is attractive for accelerating the pace of materials discovery. Here we identify, through a large-scale, multi-step computational screening process, promising zeolite structures for two energy-related applications: the purification of ethanol from fermentation broths and the hydroisomerization of alkanes with 18-30 carbon atoms encountered in petroleum refining. These results demonstrate that predictive modelling and data-driven science can now be applied to solve some of the most challenging separation problems involving highly non-ideal mixtures and highly articulated compounds.

An analysis of hydrated proton diffusion in ab initio molecular dynamics.

A detailed understanding of the inherently multiscale proton transport process raises a number of scientifically challenging questions. For example, there remain many (partially addressed) questions on the molecular mechanism for long-range proton migration and the potential for the formation of long-lived traps giving rise to burst-and-rest proton dynamics. Using results from a sizeable collection of ab initio molecular dynamics (AIMD) simulations (totaling ∼2.7 ns) with various density functional approximations (Becke-Lee-Yang-Parr (BLYP), BLYP-D3, Hamprecht-Cohen-Tozer-Handy, B3LYP) and temperatures (300-330 K), equilibrium and dynamical properties of one excess proton and 128 water molecules are studied. Two features in particular (concerted hops and weak hydrogen-bond donors) are investigated to identify modes in the system that are strongly correlated with the onset of periods of burst-and-rest dynamics. The question of concerted hops seeks to identify those time scales over which long-range proton transport can be classified as a series of sequential water hopping events or as a near-simultaneous concerted process along compressed water wires. The coupling of the observed burst-and-rest dynamics with motions of a fourth neighboring water molecule (a weak hydrogen-bond donor) solvating the protonated water molecule is also investigated. The presence (absence) of hydrogen bonds involving this fourth water molecule before and after successful proton hopping events is found to be strongly correlated with periods of burst (rest) dynamics (and consistent with pre-solvation concepts). By analyzing several realizations of the AIMD trajectories on the 100-ps time scale, convergence of statistics can be assessed. For instance, it was observed that the probability for a fourth water molecule to approach the hydronium, if not already proximal at the beginning of the lifetime of the hydronium, is very low, indicative of the formation of stable void regions. Furthermore, the correlations of the neighboring water atoms are identified as the fourth water approaches the hydronium. Finally, the temperature effects on structural and dynamical properties are studied.

Bringing Reactivity to the Aggregation-Volume-Bias Monte Carlo Based Simulation Framework: Water Nucleation Induced by a Reactive Proton.

The development of the aggregation-volume-bias Monte Carlo based simulation technique has led to recent success in studying rare nucleation events, but thus far, this simulation method has been limited to nonreactive systems. This work presents the first application of this technique to study a reactive system of relevance to atmospheric chemistry, i.e., formation of water droplets in the presence of a reactive proton, by combining this approach with a multistate empirical valence bond (MSEVB) description of the excess proton (or the hydronium). It was shown that the ability for the hydronium to share its charge with adjacent water molecules changes dramatically with the cluster size, especially when clusters are small and the distribution of the charge is affected by the presence of an interface, emphasizing the need to use this more sophisticated MSEVB model for such a reactive system. In addition, the simulation results obtained from this system are compared to those with nonreactive hard-sphere ions of different sizes. Overall, the presence of a hydronium or ions appeared to dramatically change the free energy landscape of nucleation compared to the pure water system, leading to the formation of a stable precritical cluster. Although the free energy change due to the addition of the first few water molecules was shown to be very sensitive to the ionic details, the later portion of the free energy profile was found to be nearly independent of the nature of the ion.

Prenatal stress and adult drug-seeking behavior: interactions with genes and relation to nondrug-related behavior.

Addiction inflicts large personal, social, and economic burdens, yet its etiology is poorly defined and effective treatments are lacking. As with other neuropsychiatric disorders, addiction is characterized by a core set of symptoms and behaviors that are believed to be influenced by complex gene-environment interactions. Our group focuses on the interaction between early stress and genetic background in determining addiction vulnerability. Prior work by our group and others has indicated that a history of prenatal stress (PNS) in rodents elevates adult drug seeking in a number of behavioral paradigms. The focus of the present chapter is to summarize work in the area of PNS and addiction models as well as our recent studies of PNS on drug seeking in different strains of mice as a strategy to dissect gene-environment interactions underlying cocaine addiction vulnerability. These studies indicate that ability of PNS to elevate adult cocaine seeking is strain dependent. Further, PNS also alters other nondrug behaviors in a fashion that is dependent on different strains and independent from the strain dependence of drug seeking. Thus, it appears that the ability of PNS to alter behavior related to different psychiatric conditions is orthogonal, with similar nonspecific susceptibility to prenatal stress across genetic backgrounds but with the genetic background determining the specific nature of the PNS effects. Finally, the advent of recombinant inbred mouse strains is allowing us to determine the genetic bases of these gene-environment interactions. Understanding these effects will have broad implications to determining the nature of vulnerability to addiction and perhaps other disorders.

The cost-effectiveness and public health benefit of nalmefene added to psychosocial support for the reduction of alcohol consumption in alcohol-dependent patients with high/very high drinking risk levels: a Markov model.

OBJECTIVES: To determine whether nalmefene combined with psychosocial support is cost-effective compared with psychosocial support alone for reducing alcohol consumption in alcohol-dependent patients with high/very high drinking risk levels (DRLs) as defined by the WHO, and to evaluate the public health benefit of reducing harmful alcohol-attributable diseases, injuries and deaths. DESIGN: Decision modelling using Markov chains compared costs and effects over 5 years. SETTING: The analysis was from the perspective of the National Health Service (NHS) in England and Wales. PARTICIPANTS: The model considered the licensed population for nalmefene, specifically adults with both alcohol dependence and high/very high DRLs, who do not require immediate detoxification and who continue to have high/very high DRLs after initial assessment. DATA SOURCES: We modelled treatment effect using data from three clinical trials for nalmefene (ESENSE 1 (NCT00811720), ESENSE 2 (NCT00812461) and SENSE (NCT00811941)). Baseline characteristics of the model population, treatment resource utilisation and utilities were from these trials. We estimated the number of alcohol-attributable events occurring at different levels of alcohol consumption based on published epidemiological risk-relation studies. Health-related costs were from UK sources. MAIN OUTCOME MEASURES: We measured incremental cost per quality-adjusted life year (QALY) gained and number of alcohol-attributable harmful events avoided. RESULTS: Nalmefene in combination with psychosocial support had an incremental cost-effectiveness ratio (ICER) of £5204 per QALY gained, and was therefore cost-effective at the £20,000 per QALY gained decision threshold. Sensitivity analyses showed that the conclusion was robust. Nalmefene plus psychosocial support led to the avoidance of 7179 alcohol-attributable diseases/injuries and 309 deaths per 100,000 patients compared to psychosocial support alone over the course of 5 years. CONCLUSIONS: Nalmefene can be seen as a cost-effective treatment for alcohol dependence, with substantial public health benefits. TRIAL REGISTRATION NUMBERS: This cost-effectiveness analysis was developed based on data from three randomised clinical trials: ESENSE 1 (NCT00811720), ESENSE 2 (NCT00812461) and SENSE (NCT00811941).

Systematic review, network meta-analysis and economic evaluation of biological therapy for the management of active psoriatic arthritis.

BACKGROUND: An updated economic evaluation was conducted to compare the cost-effectiveness of the four tumour necrosis factor (TNF)-α inhibitors adalimumab, etanercept, golimumab and infliximab in active, progressive psoriatic arthritis (PsA) where response to standard treatment has been inadequate. METHODS: A systematic review was conducted to identify relevant, recently published studies and the new trial data were synthesised, via a Bayesian network meta-analysis (NMA), to estimate the relative efficacy of the TNF-α inhibitors in terms of Psoriatic Arthritis Response Criteria (PsARC) response, Health Assessment Questionnaire (HAQ) scores and Psoriasis Area and Severity Index (PASI). A previously developed economic model was updated with the new meta-analysis results and current cost data. The model was adapted to delineate patients by PASI 50%, 75% and 90% response rates to differentiate between psoriasis outcomes. RESULTS: All four licensed TNF-α inhibitors were significantly more effective than placebo in achieving PsARC response in patients with active PsA. Adalimumab, etanercept and infliximab were significantly more effective than placebo in improving HAQ scores in patients who had achieved a PsARC response and in improving HAQ scores in PsARC non-responders. In an analysis using 1,000 model simulations, on average etanercept was the most cost-effective treatment and, at the National Institute for Health and Care Excellence willingness-to-pay threshold of between £20,000 to £30,000, etanercept is the preferred option. CONCLUSIONS: The economic analysis agrees with the conclusions from the previous models, in that biologics are shown to be cost-effective for treating patients with active PsA compared with the conventional management strategy. In particular, etanercept is cost-effective compared with the other biologic treatments.

Exploring the behaviour of the hydrated excess proton at hydrophobic interfaces.

The affinity of the excess proton for the aqueous solution-hydrophobic interface was examined for two specific examples, the air-water and hydrophobic wall-water cases, using a multiconfigurational molecular dynamics algorithm. The use of a reactive simulation method is important as it allows for a realistic description of the excess proton, namely, its propensity to hop between water molecules via the Grotthuss mechanism. The free energy profile reveals a minimum at these interfaces due to a favourable enthalpic term that outweighs the entropic penalty. The key factors that contribute to this enthalpic minimum were examined using a generalization of a scheme that decomposes the interaction energy into separate terms arising from various local environments [Otten et al., Proc. Natl. Acad. Sci. USA, 109, 701 (2012)] (coordination shell, bulk, and interface) and the delocalization energy (which allows the proton to hop). For both systems, it was observed that the energetic penalty for loss of coordinating water molecules as the excess proton moves toward the hydrophobic interface is more than compensated by the displacement of unfavourable interfacial water molecules. In addition, the ion becomes more delocalized, more Zundel-like, and therefore possesses a larger effective radius as it moves to the interface. The fluctuations of the instantaneous interface were reduced near the vicinity of the ion, thereby giving rise to an entropic penalty. This paper will discuss the application of energy decomposition schemes to multiconfigurational simulations and the resulting consequences realized for the excess proton at hydrophobic interfaces.

Multiscale reactive molecular dynamics.

Many processes important to chemistry, materials science, and biology cannot be described without considering electronic and nuclear-level dynamics and their coupling to slower, cooperative motions of the system. These inherently multiscale problems require computationally efficient and accurate methods to converge statistical properties. In this paper, a method is presented that uses data directly from condensed phase ab initio simulations to develop reactive molecular dynamics models that do not require predefined empirical functions. Instead, the interactions used in the reactive model are expressed as linear combinations of interpolating functions that are optimized by using a linear least-squares algorithm. One notable benefit of the procedure outlined here is the capability to minimize the number of parameters requiring nonlinear optimization. The method presented can be generally applied to multiscale problems and is demonstrated by generating reactive models for the hydrated excess proton and hydroxide ion based directly on condensed phase ab initio molecular dynamics simulations. The resulting models faithfully reproduce the water-ion structural properties and diffusion constants from the ab initio simulations. Additionally, the free energy profiles for proton transfer, which is sensitive to the structural diffusion of both ions in water, are reproduced. The high fidelity of these models to ab initio simulations will permit accurate modeling of general chemical reactions in condensed phase systems with computational efficiency orders of magnitudes greater than currently possible with ab initio simulation methods, thus facilitating a proper statistical sampling of the coupling to slow, large-scale motions of the system.

Supplying the power requirements to a sensor network using radio frequency power transfer.

Wireless power transmission is a method of supplying power to small electronic devices when there is no wired connection. One way to increase the range of these systems is to use a directional transmitting antenna, the problem with this approach is that power can only be transmitted through a narrow beam and directly forward, requiring the transmitter to always be aligned with the sensor node position. The work outlined in this article describes the design and testing of an autonomous radio frequency power transfer system that is capable of rotating the base transmitter to track the position of sensor nodes and transferring power to that sensor node. The system's base station monitors the node's energy levels and forms a charge queue to plan charging order and maintain energy levels of the nodes. Results show a radio frequency harvesting circuit with a measured S11 value of -31.5 dB and a conversion efficiency of 39.1%. Simulation and experimentation verified the level of power transfer and efficiency. The results of this work show a small network of three nodes with different storage types powered by a central base node.