Designing Angstrom-Scale Asymmetric MOF-on-MOF Cavities for High Monovalent Ion Selectivity

Biological ion channels feature angstrom-scale asymmetrical cavity structures, which are the key to achieving highly efficient separation and sensing of alkali metal ions from aqueous resources. The clean energy future and lithium-based energy storage systems heavily rely on highly efficient ionic separations. However, artificial recreation of such a sophisticated biostructure has been technically challenging. Here, a highly tunable design concept is introduced to fabricate monovalent ion-selective membranes with asymmetric sub-nanometer pores in which energy barriers are implanted. The energy barriers act against ionic movements, which hold the target ion while facilitating the transport of competing ions. The membrane consists of bilayer metal-organic frameworks (MOF-on-MOF), possessing a 6 to 3.4-angstrom passable cavity structure. The ionic current measurements exhibit an unprecedented ionic current rectification ratio of above 100 with exceptionally high selectivity ratios of 84 and 80 for K⁺ /Li⁺ and Na⁺ / Li⁺ , respectively (1.14 Li⁺ mol m^-2 h^-1 ). Furthermore, using quantum mechanics/molecular mechanics, it is shown that the combined effect of spatial hindrance and nucleophilic entrapment to induce energy surge baffles is responsible for the membrane's ultrahigh selectivity and ion rectification. This work demonstrates a striking advance in developing monovalent ion-selective channels and has implications in sensing, energy storage, and separation technologies.

Impact of changes in tricuspid regurgitation on clinical outcomes following mitral valve teer compared to guideline-directed medical therapy: a sub-analysis of the COAPT trial

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT)

Background

Prior studies suggest tricuspid regurgitation (TR) diminishes/resolves following mitral valve surgery and thus do not require treatment and may not influence outcomes.

Purpose

  We sought to evaluate the change in TR (ΔTR) and its association with outcomes after transcatheter edge-to-edge repair (TEER) compared with guideline-directed medical therapy (GDMT) in the COAPT trial.

Methods

Patients from the COAPT trial with echo core lab TR assessment at baseline and 30-day follow-up (n = 504) were included and divided into 2 groups: those whose TR worsened (ΔTR-INC) and those with no change or improvement in TR (ΔTR-SAME/DEC).  Two-year composite endpoints of death or heart failure hospitalization (HFH) and the individual components were analyzed, after excluding events occurring within the first 30 days.

Results

ΔTR-SAME/DEC occurred in 430 pts (228 TEER, 202 GDMT) while ΔTR-INC was noted in 74 pts (38 TEER, 36 GDMT) (Figure 1A). From 30 days to 2 years, ΔTR-INC pts had a higher rate of the composite outcome of death or HFH compared with ΔTR-SAME/DEC (p = 0.006, Figure 1B). Both 2-year death (HR 1.52, 95% CI 1.01-2.27; p = 0.04) and HFH (HR 1.52, 95% CI 1.04-2.22; p = 0.03) were associated with ΔTR-INC. Assessed by treatment group (Figure 1C and 1D), the relationship between ΔTR-INC and composite death or HFH was significant in GDMT alone pts (HR 1.86, 95% CI 1.21-2.86) but not in TEER pts (HR 1.33, 95% CI 0.79-2.23), although interaction testing demonstrated consistency between the two treatments  (Pint = 0.31). 

Conclusions

Worsening TR at 30 days occurred in ∼15% of pts in the COAPT trial whether they were treated with TEER or GDMT alone. DTRINC was associated with increased death and HFH during 2-year follow-up. Abstract Figure 1

Formation, collective motion, and merging of macroscopic bacterial aggregates

Chemotactic bacteria form emergent spatial patterns of variable cell density within cultures that are initially spatially uniform. These patterns are the result of chemical gradients that are created from the directed movement and metabolic activity of billions of cells. A recent study on pattern formation in wild bacterial isolates has revealed unique collective behaviors of the bacteria Enterobacter cloacae. As in other bacterial species, Enterobacter cloacae form macroscopic aggregates. Once formed, these bacterial clusters can migrate several millimeters, sometimes resulting in the merging of two or more clusters. To better understand these phenomena, we examine the formation and dynamics of thousands of bacterial clusters that form within a 22 cm square culture dish filled with soft agar over two days. At the macroscale, the aggregates display spatial order at short length scales, and the migration of cell clusters is superdiffusive, with a merging acceleration that is correlated with aggregate size. At the microscale, aggregates are composed of immotile cells surrounded by low density regions of motile cells. The collective movement of the aggregates is the result of an asymmetric flux of bacteria at the boundary. An agent-based model is developed to examine how these phenomena are the result of both chemotactic movement and a change in motility at high cell density. These results identify and characterize a new mechanism for collective bacterial motility driven by a transient, density-dependent change in motility.

Bacteria growing and swimming in soft agar often aggregate to form elaborate spatial patterns. Here we examine the patterns formed by the bacteria Enterobacter cloacae. An unusual behavior of these bacteria is the collective movement of cells after the initial aggregation into a tiny spot. Despite the majority of the cells within an aggregate being immotile at any point in the time, the flux of cells entering and leaving the aggregate, as motility is lost and regained in individual cells, led to a net, collective movement of the aggregate. These spots sometimes run into each other and combine. By looking at the cells within these spots under a microscope, we find that cells within each spot stop swimming. The process of switching back and forth between swimming and not swimming causes the movement and fusion of the spots. A numerical simulation shows that the migration and merging of these spots can be expected if the cells swim towards regions of space with high concentrations of attractant molecules and stop swimming in locations crowded with many cells. This work identifies a novel process through which populations of bacteria cooperate and control the movement of large groups of cells.

Microstructural Evaluation of Phase Instability in Large Bandgap Metal Halide Perovskites

The optoelectronic performance of organic-inorganic halide perovskite (OIHP)-based devices has been improved in recent years. Particularly, solar cells fabricated using mixed-cations and mixed-halides have outperformed their single-cation and single-halide counterparts. Yet, a systematic evaluation of the microstructural behavior of mixed perovskites is missing despite their known composition-dependent photoinstability. Here, we explore microstructural inhomogeneity in (FAPbI₃)_x(MAPbBr₃)_1-x using advanced scanning probe microscopy techniques. Contact potential difference (CPD) maps measured by Kelvin probe force microscopy show an increased fraction of grains exhibiting a low CPD with flat topography as MAPbBr₃ concentration is increased. The higher portion of low CPD contributes to asymmetric CPD distribution curves. Chemical analysis reveals these grains being rich in MA, Pb, and I. The composition-dependent phase segregation upon illumination, reflected on the emergence of a low-energy peak emission in the original photoluminescence spectra, arises from the formation of such grains with flat topology. Bias-dependent piezo-response force microscopy measurements, in these grains, further confirm vigorous ion migration and cause a hysteretic piezo-response. Our results, therefore, provide insights into the microstructural evaluation of phase segregation and ion migration in OIHPs pointing toward process optimization as a mean to further enhance their optoelectronic performance.

Development of postbiotics by whey bioconversion with Enterococcus faecalis M157 KACC81148BP and Lactococcus lactis CAU2013 KACC81152BP for treating periodontal disease and improving gut health

This study developed postbiotics with whey bioconversion product produced by Enterococcus faecalis M157 KACC 81148BP, and mixed whey bioconversion products produced by E. faecalis M157 KACC 81148BP and Lactococcus lactis ssp. lactis CAU2013 KACC 81152BP to alleviate periodontitis (PD) and to improve gut health. The powdered whey bioconversion product (EF) produced by E. faecalis M157 KACC 81148BP, mixed whey bioconversion products (EF+LL) from E. faecalis M157 KACC 81148BP and L. lactis CAU2013 KACC 81152BP, and phosphate-buffered saline (PBS; control) were administered orally to PD-induced rats for 8 wk. Infiltration of inflammatory cells and epithelial proliferation in periodontal tissue were found in control, but the lesions were reduced in PD+EF group (administration of EF to PD-induced rats), and no lesions were observed in PD+EF+LL group (administration of EF+LL to PD-induced rats). The bone loss volumes in PD+EF and PD+EF+LL groups were lower than in control. Cytokine production levels related to inflammation were lower and antioxidative stress markers were higher in PD+EF and PD+EF+LL groups than in control for both periodontal tissue and gut. The ratios of Lactobacillus spp. in gut microbiome of PD+EF and PD+EF+LL groups were higher than in control. These results indicate that the whey bioconversion product produced by E. faecalis M157 KACC 81148BP, and mixed whey bioconversion products produced by E. faecalis M157 KACC 81148BP and L. lactis CAU2013 KACC 81152BP are effective on relieving periodontitis and improving the gut health.

Using group concept mapping software to develop a conceptual framework of left ventricular assist device recipients' experiences

Background

Advanced Heart failure (AHF) carries a high mortality rate. Heart transplantation is one therapeutic option, but low donation rates limits its availability. A left ventricular assist device (LVAD) is an alternative therapy which helps relieve symptoms, while improving prognosis and quality of life. However, lack of donors also means that the LVAD becomes a destination therapy by default.(1) Living with an LVAD requires significant psychological, social and physical adaptation for the recipients' and their families.(2) Patient reported outcome measures (PROMs) are one way of capturing these concerns and ongoing problems. Discussions with a patient and public involvement group found a range of issues not currently captured by available PROMS.

Aim

To develop a conceptual framework which reflects the experiences of LVAD recipients' and evaluate their importance for inclusion in PROMs using a research web platform.

Method

Participants were recruited from a regional transplant centre which covers a wide geographical area in the UK. Ethical approval was obtained and participants were recruited through routine LVAD clinics. Group concept mapping (GCM) is a semi-quantitative mixed methods approach that can be used to capture and quantify recipients' experiences.(3) Groupwisdom concept mapping software was used as the electronic data collection platform.(4) GCM consists of 3 stages: statement generation, thematic statement sorting, and rating statements for importance, relevance and frequency of impact. Multidimensional scaling and hierarchical cluster analysis produces visual representations of recipients' experiences as a points and cluster map, and scoring of statements produces relative importance of items across the clusters.

Results

18 LVAD recipients consented to take part. 101 items and 9 clusters were generated. Clusters represented: Activities; Partner/family dependency; Travel; Mental well-being; LVAD challenges; Equipment and clothing; Physical and cognitive limitations; Restrictions, and LVAD positives. LVAD Positives and LVAD restrictions were rated high for frequency, relevance and importance. Physical and cognitive limitations was rated high for importance and frequency. Equipment was rated high for relevance and frequency, and Challenges was rated high for relevance.

Conclusion

GCM and the online software is a useful tool for developing a conceptual framework and mapping key areas of importance for LVAD recipients, especially, when prioritising important patient reported outcome domains for use in clinical practice, future research and design evolution. Using an electronic platform allowed us to reach participants dispersed over a wide geographical area.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): British Heart FoundationNational Institute for Health Research Cluster Rating Map for Importance

Left ventricular assist device therapy improves severe secondary mitral regurgitation without mitral valve repair

Background

Severe secondary mitral regurgitation (MR) worsens prognosis in patients with medically managed heart failure (HF). In patients treated by left ventricular assist device (LVAD), it is unclear whether severe MR should be corrected at time of LVAD implantation.

Purpose

To evaluate impact of LVAD therapy on severe and non-severe secondary MR over 1 year.

Methods

Retrospective single centre study of consecutive patients who underwent HeartMate (HM)2 or HM3 LVAD implantation between January 2011 and March 2020.

Results

Of 155 patients, 20 were excluded due to LVAD exchange (n=10), mitral valve repair (n=1), or inaccessible pre-LVAD echocardiography (n=9). Based on multiparametric grading, 29/135 patients had severe secondary MR and 106/135 had non-severe secondary MR (including none). Severe MR patients were more often female [10/29 (34%) vs 11/106 (10%); p=0.002] but were of similar age (54±12 vs 55±9 years; p=0.624), size (27±5 vs 27±4 kg/m2; p=1.0), with equivalent renal function (53±22 vs 55±20 ml/min/1.73m2; p=0.641) and median pre-operative NT-proBNP [4076 (IQR 206–5438) vs 4914 (IQR 2706–7518) ng/L; p=0.488]. There were similar proportions of patients with ischaemic aetiology [16/29 (55%) vs 66/106 (62%); p=0.488) and those receiving HM2 [11/29 (38%) vs 32/106 (30%)] and HM3 [18/29 (62%) vs 74/106 (70%); p=0.575] LVAD. Echocardiography before LVAD implantation demonstrated similar left ventricular (LV) size (LV end-diastolic volume: 133±44 vs 118±50ml/m2; p=0.145, end-systolic volume: 107±41 vs 96±59ml/m2; p=0.348) and LV ejection fraction (17±9 vs 17±7%; p=1.0). Severe MR patients had significantly greater (p<0.001) MR by proximal isovolumetric surface area (0.93±0.27 vs 0.60±0.16cm), vena contracta (0.79±0.32 vs 0.57±0.18cm), regurgitant volume (47±25 vs 24±12ml), and fraction (54±15 vs 37±13%). Follow-up (f/u) echocardiography was performed at a median 222 days (range 356 days). Patients who received cardiac transplantation before f/u echocardiography were excluded. Relative severities of MR at f/u were: none = 12 (46%), mild = 8 (31%), moderate = 5 (19%), severe = 1 (4%) amongst patients with severe MR pre-LVAD, and none = 55 (58%), mild = 26 (27%), moderate = 13 (14%), severe = 1 (1%) amongst patients with non-severe MR pre-LVAD. At 1-year, after excluding all patients who underwent cardiac transplantation (severe MR n=4; non-severe MR n=2), rates of HF hospitalisation [5/25 (20%) vs 16/104 (15%); p=0.575] and all-cause mortality [2/25 (18%) vs 22/104 (21%); p=0.129)] were similar, irrespective of pre-LVAD MR severity. No patient who died during follow-up had severe MR prior to death.

Conclusion

LVAD improves severe secondary MR in 96% of cases, resulting in 1-year rates of HF hospitalisation and mortality similar to patients without severe MR pre-LVAD. These data suggest mitral valve surgery at time of LVAD implantation is not warranted.

Funding Acknowledgement

Type of funding sources: None.

Longitudinal evaluation of laboratory-based serological assays for SARS-CoV-2 antibody detection

Serological assays for SARS-CoV-2 infection are now widely available for use in diagnostic laboratories. Limited data are available on the performance characteristics in different settings, and at time periods remote from the initial infection. Validation of the Abbott (Architect SARS-CoV-2 IgG), DiaSorin (Liaison SARS-CoV-2 S1/S2 IgG) and Roche (Cobas Elecsys Anti-SARS-CoV-2) assays was undertaken utilising 217 serum samples from 131 participants up to 7 months following COVID-19 infection. The Abbott and DiaSorin assays were implemented into routine laboratory workflow, with outcomes reported for 2764 clinical specimens. Sensitivity and specificity were concordant with the range reported by the manufacturers for all assays. Sensitivity across the convalescent period was highest for the Roche at 95.2-100% (95% CI 81.0-100%), then the DiaSorin at 88.1-100% (95% CI 76.0-100%), followed by the Abbott 68.2-100% (95% CI 53.4-100%). Sensitivity of the Abbott assay fell from approximately 5 months; on this assay paired serum samples for 45 participants showed a significant drop in the signal-to-cut-off ratio and 10 sero-reversion events. When used in clinical practice, all samples testing positive by both DiaSorin and Abbott assays were confirmed as true positive results. In this low prevalence setting, despite high laboratory specificity, the positive predictive value of a single positive assay was low. Comprehensive validation of serological assays is necessary to determine the optimal assay for each diagnostic setting. In this low prevalence setting we found implementation of two assays with different antibody targets maximised sensitivity and specificity, with confirmatory testing necessary for any sample which was positive in only one assay.

Oxygen Nucleation of MoS2 Nanosheet Thin Film Supercapacitor Electrodes for Enhanced Electrochemical Energy Storage

A direct thin film approach to fabricate large-surface MoS₂ nanosheet thin film supercapacitors using the solution-based diffusion of thiourea into an anodized MoO₃ thin film was investigated. A dense MoS₂ nanosheet thin film electrode (D-MoS₂ ) was obtained when the anodized MoO₃ thin film was processed in a low thiourea solution concentration, whereas a highly porous MoS₂ nanosheet thin film electrode (P-MoS₂ ) was formed at a higher thiourea solution concentration. The charge storage performances of the D-MoS₂ and P-MoS₂ thin films displayed an unusual increase in capacitance on extended cycling, leading to a capacitance as high as around 5-8 mF cm^-2 . X-ray diffraction and cross-sectional microscopy revealed the capacitance enhancements of the MoS₂ supercapacitors are attributable to the nucleation of a new MoS_2-x O_x phase upon cycling. For the D-MoS₂ nanosheet thin film, the formation and growth of the MoS_2-x O_x phase during cycling was accompanied by a volumetric expansion of the MoS₂ layer. For the P-MoS₂ thin film, the nucleation and growth of the MoS_2-x O_x phase occurred in the pores of the MoS₂ layer. The propagation of the MoS_2-x O_x phase also shifted the charge storage process in both films from a diffusion-limited process to a capacitive-dominant process.

Downstream effects of polypathology on neurodegeneration of medial temporal lobe subregions

The medial temporal lobe (MTL) is a nidus for neurodegenerative pathologies and therefore an important region in which to study polypathology. We investigated associations between neurodegenerative pathologies and the thickness of different MTL subregions measured using high-resolution post-mortem MRI. Tau, TAR DNA-binding protein 43 (TDP-43), amyloid-β and α-synuclein pathology were rated on a scale of 0 (absent)-3 (severe) in the hippocampus and entorhinal cortex (ERC) of 58 individuals with and without neurodegenerative diseases (median age 75.0 years, 60.3% male). Thickness measurements in ERC, Brodmann Area (BA) 35 and 36, parahippocampal cortex, subiculum, cornu ammonis (CA)1 and the stratum radiatum lacunosum moleculare (SRLM) were derived from 0.2 × 0.2 × 0.2 mm3 post-mortem MRI scans of excised MTL specimens from the contralateral hemisphere using a semi-automated approach. Spearman's rank correlations were performed between neurodegenerative pathologies and thickness, correcting for age, sex and hemisphere, including all four proteinopathies in the model. We found significant associations of (1) TDP-43 with thickness in all subregions (r =  - 0.27 to r =  - 0.46), and (2) tau with BA35 (r =  - 0.31) and SRLM thickness (r =  - 0.33). In amyloid-β and TDP-43 negative cases, we found strong significant associations of tau with ERC (r =  - 0.40), BA35 (r =  - 0.55), subiculum (r =  - 0.42) and CA1 thickness (r =  - 0.47). This unique dataset shows widespread MTL atrophy in relation to TDP-43 pathology and atrophy in regions affected early in Braak stageing and tau pathology. Moreover, the strong association of tau with thickness in early Braak regions in the absence of amyloid-β suggests a role of Primary Age-Related Tauopathy in neurodegeneration.