Off-axis electron holography of bacterial cells and magnetic nanoparticles in liquid

The mapping of electrostatic potentials and magnetic fields in liquids usingelectron holography has been considered to be unrealistic. Here, we showthat hydrated cells ofMagnetospirillum magneticumstrain AMB-1 and assem-blies of magnetic nanoparticles can be studied using off-axis electronholography in a fluid cell specimen holder within the transmission electronmicroscope. Considering that the holographic object and reference waveboth pass through liquid, the recorded electron holograms show sufficientinterference fringe contrast to permit reconstruction of the phase shift ofthe electron wave and mapping of the magnetic induction from bacterialmagnetite nanocrystals. We assess the challenges of performingin situmagne-tization reversal experiments using a fluid cell specimen holder, discussapproaches for improving spatial resolution and specimen stability, and outlinefuture perspectives for studying scientific phenomena, ranging from interpar-ticle interactions in liquids and electrical double layers at solid–liquidinterfaces to biomineralization and the mapping of electrostatic potentialsassociated with protein aggregation and folding

Discovery of Anion Insertion Electrochemistry in Layered Hydroxide Nanomaterials

Electrode materials which undergo anion insertion are a void in the materials innovation landscape and a missing link to energy efficient electrochemical desalination. In recent years layered hydroxides (LHs) have been studied for a range of electrochemical applications, but to date have not been considered as electrode materials for anion insertion electrochemistry. Here, we show reversible anion insertion in a LH for the first time using Co and Co-V layer hydroxides. By pairing in situ synchrotron and quartz crystal microbalance measurements with a computational unified electrochemical band-diagram description, we reveal a previously undescribed anion-insertion mechanism occurring in Co and Co-V LHs. This proof of concept study demonstrates reversible electrochemical anion insertion in LHs without significant material optimization. These results coupled with our foundational understanding of anion insertion electrochemistry establishes LHs as a materials platform for anion insertion electrochemistry with the potential for future application to electrochemical desalination

Creation of Rydberg Polarons in a Bose Gas

We report spectroscopic observation of Rydberg polarons in an atomic Bose gas. Polarons are created by excitation of Rydberg atoms as impurities in a strontium Bose-Einstein condensate. They are distinguished from previously studied polarons by macroscopic occupation of bound molecular states that arise from scattering of the weakly bound Rydberg electron from ground-state atoms. The absence of a $p$-wave resonance in the low-energy electron-atom scattering in Sr introduces a universal behavior in the Rydberg spectral lineshape and in scaling of the spectral width (narrowing) with the Rydberg principal quantum number, $n$. Spectral features are described with a functional determinant approach (FDA) that solves an extended Fr\"{o}hlich Hamiltonian for a mobile impurity in a Bose gas. Excited states of polyatomic Rydberg molecules (trimers, tetrameters, and pentamers) are experimentally resolved and accurately reproduced with FDA.Comment: 5 pages, 3 figure

Theory of excitation of Rydberg polarons in an atomic quantum gas

We present a quantum many-body description of the excitation spectrum of Rydberg polarons in a Bose gas. The many-body Hamiltonian is solved with functional determinant theory, and we extend this technique to describe Rydberg polarons of finite mass. Mean-field and classical descriptions of the spectrum are derived as approximations of the many-body theory. The various approaches are applied to experimental observations of polarons created by excitation of Rydberg atoms in a strontium Bose-Einstein condensate.Comment: 14 pages, 9 figures. arXiv admin note: substantial text overlap with arXiv:1706.0371

Vedolizumab for the Treatment of Adults with Moderate-to-Severe Active Ulcerative Colitis: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

As part of its single technology appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the manufacturer of vedolizumab (Takeda UK) to submit evidence of the clinical effectiveness and cost effectiveness of vedolizumab for the treatment of patients with moderate-to-severe active ulcerative colitis (UC). The Evidence Review Group (ERG) produced a critical review of the evidence for the clinical effectiveness and cost effectiveness of the technology, based upon the company's submission to NICE. The evidence was derived mainly from GEMINI 1, a Phase 3, multicentre, randomised, double-blinded, placebo-controlled study of the induction and maintenance of clinical response and remission by vedolizumab (MLN0002) in patients with moderate-to-severe active UC with an inadequate response to, loss of response to or intolerance of conventional therapy or anti-tumour necrosis factor (TNF)-α. The clinical evidence showed that vedolizumab performed significantly better than placebo in both the induction and maintenance phases. In the post hoc subgroup analyses in patients with or without prior anti-TNF-α therapy, vedolizumab performed better then placebo (p value not reported). In addition, a greater improvement in health-related quality of life was observed in patients treated with vedolizumab, and the frequency and types of adverse events were similar in the vedolizumab and placebo groups, but the evidence was limited to short-term follow-up. There were a number of limitations and uncertainties in the clinical evidence base, which warrants caution in its interpretation-in particular, the post hoc subgroup analyses and high dropout rates in the maintenance phase of GEMINI 1. The company also presented a network meta-analysis of vedolizumab versus other biologic therapies indicated for moderate-to-severe UC. However, the ERG considered that the results presented may have underestimated the uncertainty in treatment effects, since fixed-effects models were used, despite clear evidence of heterogeneity among the trials included in the network. Results from the company's economic evaluation (which included price reductions to reflect the proposed patient access scheme for vedolizumab) suggested that vedolizumab is the most effective option compared with surgery and conventional therapy in the following three populations: (1) a mixed intention-to-treat population, including patients who have previously received anti-TNF-α therapy and those who are anti-TNF-α naïve; (2) patients who are anti-TNF-α naïve only; and (3) patients who have previously failed anti-TNF-α therapy only. The ERG concluded that the results of the company's economic evaluation could not be considered robust, because of errors in model implementation, omission of relevant comparators, deviations from the NICE reference case and questionable model assumptions. The ERG amended the company's model and demonstrated that vedolizumab is expected to be dominated by surgery in all three populations