We study both in silico and in vivo the real-time feedback control of a molecular titration motif that has been earmarked as a fundamental component of antithetic and multicellular feedback control schemes in E. coli. We show that an external feedback control strategy can successfully regulate the average fluorescence output of a bacterial cell population to a desired constant level in real-time. We also provide in silico evidence that the same strategy can be used to track a time-varying reference signal where the set-point is switched to a different value halfway through the experiment. We use the experimental data to refine and parameterize an in silico model of the motif that can be used as an error computation module in future embedded or multicellular control experiments. the experimental work described in this paper. The authors thank Dr Dan Rocca and Dr Elisa Pedone for support with the microfluidics platform set-up, and Dr Mark Jepson and Alan Leard (Wolfson Imaging Facility, University of Bristol) for supporting live-cell imaging experiments.

Introduction: COVID-19 vaccination is widely recommended as a prevention strategy; however, vaccine uptake is disproportionately lower among rural Americans compared to their urban counterparts. Development of public health activities to address the rural-urban vaccine gap requires an understanding of determinants of vaccine hesitation. The present study explores perceptions of and barriers to COVID-19 vaccination among rural Oklahomans. Methods: Between March and May 2021, 222 residents, unvaccinated for COVID-19, within rural Oklahoma counties completed a cross-sectional, online questionnaire to qualitatively assess perceptions, benefits, and concerns regarding getting vaccinated for COVID-19.Results: Approximately two-fifths of rural respondents in the present study were hesitant to get vaccinated, even when a vaccine was made available to them. Major factors included limited knowledge and understanding about the vaccine, including potential side-effects and long-term complications, as well as skepticism surrounding COVID-19 vaccine development and efficacy. Among the potential perceived benefits of vaccination were protecting the health of vulnerable individuals and the ability to return to normal day-to-day activities. Conclusion:Increases in COVID-19 cases and deaths in rural areas are expected to continue as new variants are introduced within communities. The present findings highlight the need for the development of culturally tailored vaccine information, to be disseminated by local leaders within rural communities.

Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane.

Co is a common catalyst for the Fischer-Tropsch process which synthesises liquid paraffins from CO and H2. The metal particles are typically a few nm in size supported on an oxide such as γ-alumina. The alumina is impregnated with a salt of Co and calcined in air to form the spinel Co3O4. The Co particles are then produced by reduction of this oxide in H2 in two steps [1]. To maximize the surface area for reaction, promoters such as Re, Pt, Ir or Ru are added. These lower the temperatures at which each reduction step occurs and thereby inhibit sintering. However a typical recipe might involve 20 wt% Co and 1 wt% of the PGM (platinum group metal). This is very costly. As part of a study to understand how the promotion works with a view to lowering the PGM content, HAADF imaging on the aberration-corrected VG501 STEM (Nion-corrector) at SuperSTEM was used to attempt to image the positions of the promoter atoms after full reduction [1]. Not all the expected PGM atoms were observed and there are several possible reasons for this. However, of these the one that fundamentally undermines the experiment is the physics of the electron interactions with the PGM atoms in a relatively heavy matrix.Multislice simulations including thermal diffuse scattering using the codes of Kirkland [2] and Koch [3] showed that for the standard conditions on this instrument (100keV, convergence angle 24 mrad, HAADF detector inner angle 70 mrad and outer angle 210 mrad) the contrast of the PGM atoms was a very strong function of its depth within the crystal relative to the incident beam [1]. Two models of FCC Co were generated; one a parallel sided foil and the other a cube-octahedral particle about 3.5nm in size. Re and Ru were chosen to represent the promoter atoms. For the foil a single dopant (promoter) atom was positioned at a number of depths whilst parameters such as Cs and defocus were varied.The visibility of the dopant atoms is not at the optimum focus for the Co crystal itself as shown in Fig 1 where a dopant atom is in the exit surface of a 29 layer crystal in [110] orientation. For the conditions given the Co lattice is in sharpest focus at 5.5nm defocus whilst the Re is most readily detected when the Co lattice contrast is minimal at -4-6nm.The effect of the depth of the dopant is shown in Fig 2(a). Each column contains 8 atoms. Columns 1, 2, 3 and 8 contain Co only whilst, in the direction of the incident beam, Co atoms 6, 7, 3 and 3 of columns 4, 5, 6 and 7 respectively are replaced by Re. Clearly those nearest the exit surface exhibit highest contrast. Indeed 2 Re atoms in a column in positions 1 and 2 would show less contrast than 1 atom in position 7 and a single Re atom in position 1 would be barely detectable. The contrast variation with depth is useful provided the number of heavy atoms in a column is known. Recent simulations involving more careful consideration of the inner and outer angles of the annular dark field detector suggest that it is possible to design an experiment in which the number of dopant atoms in a ...

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