Variationally consistent modeling of a sensor-actuator based on shape-morphing from electro-chemical–mechanical interactions

This paper concerns the computational modeling of a class of carbon fiber composites, known as shape-morphing and strain-sensing composites. The actuating and sensing performance of such (smart) materials is achieved by the interplay between electrochemistry and mechanics, in particular the ability of carbon fibers to (de)intercalate Li-ions repeatedly. We focus on the actuation and sensing properties of a beam in conjunction with the appropriate “through-the-thickness” properties. Thus, the electro-chemo-mechanical analysis is essentially two-dimensional, and it is possible to rely heavily on the results in Carlstedt et al. (2020). More specifically, the cross-sectional design is composed of two electrodes, consisting of (partly) lithiated carbon fibers embedded in structural battery electrolyte (SBE), on either side of a separator. As a result, the modeling is hierarchical in the sense that (macroscale) beam action is combined with electro-chemo-mechanical interaction along the beam. The setup is able to work as sensor or actuator depending on the choice of control (and response) variables. Although quite idealized, this design allows for a qualitative investigation. In this paper we demonstrate the capability of the developed framework to simulate both the actuator and sensor modes. As proof of concept, we show that both modes of functionality can be captured using the developed framework. For the actuator mode, the predicted deformation is found to be in close agreement with experimental data. Further, the sensor-mode is found to agree with experimental data available in the literature

Massive pulmonary embolism in patients with extreme bleeding risk: a case series on the successful use of ultrasound-assisted, catheter directed thrombolysis in a district general hospital

This is the final version. Available from the publisher via the DOI in this record.Massive pulmonary embolism (PE), characterised by profound arterial hypotension, is a life-threatening emergency with a 90-day mortality of over 50%. Systemic thrombolysis can signifcantly reduce the risk of death or cardiovascular collapse in these patients, by around 50%, but these benefts are ofset by a fvefold increased risk of intracranial haemorrhage and major bleeding, which may limit its use in patients at high risk of catastrophic haemorrhage. We describe a case series of 3 patients presenting with massive PE, each with extreme risk of bleeding and contra-indication to systemic thrombolysis, treated successfully with ultrasound-assisted, catheter directed thrombolysis (U-ACDT). Our experience of this novel technique using the EkoSonic Endovascular System (Ekos, BTG, London, UK) on carefully selected patients has demonstrated the potential to improve clinical status in shocked patients, with minimal bleed risk. There have been several clinical studies evaluating the Ekos system. Both the ULTIMA and SEATTLE II studies have shown signifcant reductions in RV/LV ratio by CT scanning when compared to standard anticoagulation in patients with intermediate-risk PE, with minimal bleeding complications. However, there is a pressing need for a randomised trial demonstrating improvement in robust clinical outcomes when comparing U-ACDT to simple anticoagulation. We believe that this case series adds new insight and highlights the potential of catheter directed thrombolysis in this high-risk patient cohort and consideration should be made to its use in cases where systemic thrombolysis is felt to be too high ris

The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses

The contents of the colon of the Tyrolean Iceman who lived Ga. 5300 years ago include muscle fibres, cereal remains, a diversity of pollen, and most notably that of the hop hornbeam (Ostrya carpinifolia) retaining cellular contents, as well as a moss leaf (Neckera complanata) and eggs of the parasitic whipworm (Trichuris trichiura). Based almost solely on stable isotope analyses and ignoring the work on the colon contents, two recently published papers on the Iceman's diet draw ill- founded conclusions about vegetarianism and even veganism. Neither the pollen nor the moss is likely to have been deliberately consumed as food by the Iceman. All the available evidence concerning the Iceman's broad-based diet is reviewed and the significance of the colon contents for matters other than assessment of food intake is outlined

Computational modelling of structural batteries accounting for stress-assisted convection in the electrolyte

Structural batteries consist of carbon fibres embedded in a porous structural battery electrolyte (SBE), which is composed of two continuous phases: a solid polymer skeleton and a liquid electrolyte containing Li-salt. In this paper we elaborate on a computational modelling framework to study the electro-chemo-mechanical properties of such structural batteries while accounting for the combined action from migration as well as stress-assisted diffusion and convection in the electrolyte. Further, we consider effects of lithium insertion in the carbon fibres, leading to insertion strains. The focus is placed on how the convective contribution to the mass transport within the SBE affects the general electro-chemo-mechanical properties. The numerical results indicate that the convective contribution has only minor influence on the multifunctional performance when the mechanical loading is caused by constrained deformation of constituents during electro-chemical cycling. However, in the case of externally applied mechanical loading that causes severe deformation of the SBE, or when large current pulses are applied, the convective contribution has noticeable influence on the electro-chemical performance. In addition, it is shown that the porosity of the SBE, which affects the effective stiffness as well as the mobility and permeability, has significant influence on the combined mechanical and electro-chemical performance

Finite Element Simulation of the Performance of a Structural Electrolyte

This contribution concerns the multi-scale and multi-physics finite element analysis of structural power composites, i.e. multifunctional composites with simultaneous load bearing and energy storing functionality. We are particularly interested in obtaining the effective macro-scale properties of the structural electrolyte by employing computational homogenization to capture the effects of micro-heterogeneities on the sub-scale. The sub-scale problem is defined by a statistical volume element that is numerically generated, and the effective properties are obtained by conducting virtual material testing on the synthetic microstructure

The switch-like expression of heme-regulated kinase 1 mediates neuronal proteostasis following proteasome inhibition

We examined the feedback between the major protein degradation pathway, the ubiquitin-proteasome system (UPS), and protein synthesis in rat and mouse neurons. When protein degradation was inhibited, we observed a coordinate dramatic reduction in nascent protein synthesis in neuronal cell bodies and dendrites. The mechanism for translation inhibition involved the phosphorylation of eIF2alpha, surprisingly mediated by eIF2alpha kinase 1, or heme-regulated kinase inhibitor (HRI). Under basal conditions, neuronal expression of HRI is barely detectable. Following proteasome inhibition, HRI protein levels increase owing to stabilization of HRI and enhanced translation, likely via the increased availability of tRNAs for its rare codons. Once expressed, HRI is constitutively active in neurons because endogenous heme levels are so low; HRI activity results in eIF2alpha phosphorylation and the resulting inhibition of translation. These data demonstrate a novel role for neuronal HRI that senses and responds to compromised function of the proteasome to restore proteostasis

A global point prevalence survey of antimicrobial use in neonatal intensive care units : the no-more-antibiotics and resistance (NO-MAS-R) study

Background: Global assessment of antimicrobial agents prescribed to infants in the neonatal intensive care unit (NICU) may inform antimicrobial stewardship efforts. Methods: We conducted a one-day global point prevalence study of all antimicrobials provided to NICU infants. Demographic, clinical, and microbiologic data were obtained including NICU level, census, birth weight, gestational/chronologic age, diagnoses, antimicrobial therapy (reason for use; length of therapy), antimicrobial stewardship program (ASP), and 30-day in-hospital mortality. Findings: On July 1, 2019, 26% of infants (580/2,265; range, 0 100%; median gestational age, 33 weeks; median birth weight, 1800 g) in 84 NICUs (51, high-income; 33, low-to-middle income) from 29 countries (14, high-income; 15, low-to-middle income) in five continents received >=1 antimicrobial agent (92%, antibacterial; 19%, antifungal; 4%, antiviral). The most common reasons for antibiotic therapy were “rule-out” sepsis (32%) and “culture-negative” sepsis (16%) with ampicillin (40%), gentamicin (35%), amikacin (19%), vancomycin (15%), and meropenem (9%) used most frequently. For definitive treatment of presumed/confirmed infection, vancomycin (26%), amikacin (20%), and meropenem (16%) were the most prescribed agents. Length of therapy for culture-positive and “culture-negative” infections was 12 days (median; IQR, 8-14) and 7 days (median; IQR, 5-10), respectively. Mortality was 6% (42%, infection-related). An NICU ASP was associated with lower rate of antibiotic utilization (p = 0.02). Interpretation: Global NICU antibiotic use was frequent and prolonged regardless of culture results. NICU-specific ASPs were associated with lower antibiotic utilization rates, suggesting the need for their implementation worldwide

Robust numerical analysis of fibrous composites from X-ray computed tomography image data enabling low resolutions

X-ray computed tomography scans can provide detailed information about the state of the material after manufacture and in service. X-ray computed tomography aided engineering (XAE) was recently introduced as an automated process to transfer 3D image data to finite element models. The implementation of a structure tensor code for material orientation analysis in combination with a newly developed integration point-wise fibre orientation mapping allows an easy applicable, computationally cheap, fast, and accurate model set-up. The robustness of the proposed approach is demonstrated on a non-crimp fabric glass fibre reinforced composite for a low resolution case with a voxel size of 64 μm corresponding to more than three times the fibre diameter. Even though 99.8% of the original image data is removed, the simulated elastic modulus of the considered non-crimp fabric composite is only underestimated by 4.7% compared to the simulation result based on the original high resolution scan

Acceptability of HIV self-sampling kits (TINY vial) among people of black African ethnicity in the UK: a qualitative study

Background: Increasing routine HIV testing among key populations is a public health imperative, so improving access to acceptable testing options for those in need is a priority. Despite increasing targeted distribution and uptake of HIV self-sampling kits (SSKs) among men who have sex with men in the UK, little is known about why targeted SSK interventions for black African users are not as wide-spread or well-used. This paper addresses this key gap, offering insight into why some groups may be less likely than others to adopt certain types of SSK interventions in particular contexts. These data were collected during the development phase of a larger study to explore the feasibility and acceptability of targeted distribution of SSKs to black African people. Methods: We undertook 6 focus groups with members of the public who self-identified as black African (n = 48), 6 groups with specialists providing HIV and social services to black African people (n = 53), and interviews with HIV specialist consultants and policy-makers (n = 9). Framework analysis was undertaken, using inductive and deductive analysis to develop and check themes. Results: We found three valuable components of targeted SSK interventions for this population: the use of settings and technologies that increase choice and autonomy; targeted offers of HIV testing that preserve privacy and do not exacerbate HIV stigma; and ensuring that the specific kit being used (in this case, the TINY vial) is perceived as simple and reliable. Conclusions: This unique and rigorous research offers insights into participants’ views on SSK interventions, offering key considerations when targeting this population.. Given the plethora of HIV testing options, our work demonstrates that those commissioning and delivering SSK interventions will need to clarify (for users and providers) how each kit type and intervention design adds value. Most significantly, these findings demonstrate that without a strong locus of control over their own circumstances and personal information, black African people are less likely to feel that they can pursue an HIV test that is safe and secure. Thus, where profound social inequalities persist, so will inequalities in HIV testing uptake – by any means