CO2 Electrolyzers

CO2 electrolyzers have progressed rapidly in energy efficiency and catalyst selectivity toward valuable chemical feedstocks and fuels, such as syngas, ethylene, ethanol, and methane. However, each component within these complex systems influences the overall performance, and the further advances needed to realize commercialization will require an approach that considers the whole process, with the electrochemical cell at the center. Beyond the cell boundaries, the electrolyzer must integrate with upstream CO2 feeds and downstream separation processes in a way that minimizes overall product energy intensity and presents viable use cases. Here we begin by describing upstream CO2 sources, their energy intensities, and impurities. We then focus on the cell, the most common CO2 electrolyzer system architectures, and each component within these systems. We evaluate the energy savings and the feasibility of alternative approaches including integration with CO2 capture, direct conversion of flue gas and two-step conversion via carbon monoxide. We evaluate pathways that minimize downstream separations and produce concentrated streams compatible with existing sectors. Applying this comprehensive upstream-to-downstream approach, we highlight the most promising routes, and outlook, for electrochemical CO2 reduction.

Ligand-modified nanoparticle surfaces influence CO electroreduction selectivity

Improving the kinetics and selectivity of CO2/CO electroreduction to valuable multi-carbon products is a challenge for science and is a requirement for practical relevance. Here we develop a thiol-modified surface ligand strategy that promotes electrochemical CO-to-acetate. We explore a picture wherein nucleophilic interaction between the lone pairs of sulfur and the empty orbitals of reaction intermediates contributes to making the acetate pathway more energetically accessible. Density functional theory calculations and Raman spectroscopy suggest a mechanism where the nucleophilic interaction increases the sp2 hybridization of CO(ad), facilitating the rate-determining step, CO* to (CHO)*. We find that the ligands stabilize the (HOOC-CH2)* intermediate, a key intermediate in the acetate pathway. In-situ Raman spectroscopy shows shifts in C-O, Cu-C, and C-S vibrational frequencies that agree with a picture of surface ligand-intermediate interactions. A Faradaic efficiency of 70% is obtained on optimized thiol-capped Cu catalysts, with onset potentials 100 mV lower than in the case of reference Cu catalysts.

Selective Suppression of Integrin-Ligand Binding by Single Molecular Tension Probes Mediates Directional Cell Migration

Cell migration interacting with continuously changing microenvironment, is one of the most essential cellular functions, participating in embryonic development, wound repair, immune response, and cancer metastasis. The migration process is finely tuned by integrin-mediated binding to ligand molecules. Although numerous biochemical pathways orchestrating cell adhesion and motility are identified, how subcellular forces between the cell and extracellular matrix regulate intracellular signaling for cell migration remains unclear. Here, it is showed that a molecular binding force across integrin subunits determines directional migration by regulating tension-dependent focal contact formation and focal adhesion kinase phosphorylation. Molecular binding strength between integrin αvβ3 and fibronectin is precisely manipulated by developing molecular tension probes that control the mechanical tolerance applied to cell-substrate interfaces. This data reveals that integrin-mediated molecular binding force reduction suppresses cell spreading and focal adhesion formation, attenuating the focal adhesion kinase (FAK) phosphorylation that regulates the persistence of cell migration. These results further demonstrate that manipulating subcellular binding forces at the molecular level can recapitulate differential cell migration in response to changes of substrate rigidity that determines the physical condition of extracellular microenvironment. Novel insights is provided into the subcellular mechanics behind global mechanical adaptation of the cell to surrounding tissue environments featuring distinct biophysical signatures.

Serine synthesis pathway upregulated by E-cadherin is essential for the proliferation and metastasis of breast cancers

The loss of E-cadherin (E-cad), an epithelial cell adhesion molecule, has been implicated in the epithelial-mesenchymal transition (EMT), promoting invasion and migration of cancer cells and, consequently, metastasis. However, recent studies have demonstrated that E-cad supports the survival and proliferation of metastatic cancer cells, suggesting that our understanding of E-cad in metastasis is far from comprehensive. Here, we report that E-cad upregulates the de novo serine synthesis pathway (SSP) in breast cancer cells. The SSP provides metabolic precursors for biosynthesis and resistance to oxidative stress, critically beneficial for E-cad-positive breast cancer cells to achieve faster tumor growth and more metastases. Inhibition of PHGDH, a rate-limiting enzyme in the SSP, significantly and specifically hampered the proliferation of E-cad-positive breast cancer cells and rendered them vulnerable to oxidative stress, inhibiting their metastatic potential. Our findings reveal that E-cad adhesion molecule significantly reprograms cellular metabolism, promoting tumor growth and metastasis of breast cancers.

Stretching of porous poly (l-lactide-co-ε-caprolactone) membranes regulates the differentiation of mesenchymal stem cells

Background: Among a variety of biomaterials supporting cell growth for therapeutic applications, poly (l-lactide-co-ε-caprolactone) (PLCL) has been considered as one of the most attractive scaffolds for tissue engineering owing to its superior mechanical strength, biocompatibility, and processibility. Although extensive studies have been conducted on the relationship between the microstructure of polymeric materials and their mechanical properties, the use of the fine-tuned morphology and mechanical strength of PLCL membranes in stem cell differentiation has not yet been studied. Methods: PLCL membranes were crystallized in a combination of diverse solvent-nonsolvent mixtures, including methanol (MeOH), isopropanol (IPA), chloroform (CF), and distilled water (DW), with different solvent polarities. A PLCL membrane with high mechanical strength induced by limited pore formation was placed in a custom bioreactor mimicking the reproducible physiological microenvironment of the vascular system to promote the differentiation of mesenchymal stem cells (MSCs) into smooth muscle cells (SMCs). Results: We developed a simple, cost-effective method for fabricating porosity-controlled PLCL membranes based on the crystallization of copolymer chains in a combination of solvents and non-solvents. We confirmed that an increase in the ratio of the non-solvent increased the chain aggregation of PLCL by slow evaporation, leading to improved mechanical properties of the PLCL membrane. Furthermore, we demonstrated that the cyclic stretching of PLCL membranes induced MSC differentiation into SMCs within 10 days of culture. Conclusion: The combination of solvent and non-solvent casting for PLCL solidification can be used to fabricate mechanically durable polymer membranes for use as mechanosensitive scaffolds for stem cell differentiation.

Assay interference as a cause of false positive troponin T elevation in emergency department patients

BACKGROUND

Troponin assays are used in the diagnosis of myocardial injury and may show elevated results for a variety of reasons. However it is increasingly recognised that cardiac troponin elevation may in some cases be due to assay interference. This is of significant importance as a misdiagnosis of myocardial injury may lead to unnecessary and potentially harmful investigation and treatment for patients. We sought to confirm the accuracy of cardiac high sensitivity troponin T (chsTnT) elevation in an unselected group of patients presenting to the emergency department, by using a second confirmatory cardiac high sensitivity troponin I (chsTnI) assay.

METHODS

We identified patients presenting to two local emergency departments over a five-day period who had chsTnT levels measured as part of routine clinical care. All samples with elevated chsTnT levels (above the 99% centile URL) were retested for chsTnI in order to confirm true myocardial injury.

RESULTS

A total of 74 samples from 54 patients were analysed for chsTnT and chsTnI. 7 samples (9.5%) had chsTnI levels < 5 ng/L suggesting assay interference as the cause of chsTnT elevation.

CONCLUSIONS

Assay interference leading to false positive troponin elevation may be more common than many physicians appreciate and can potentially lead to harmful investigation and treatment for patients. In cases where the diagnosis of myocardial injury is uncertain, a second alternative troponin assay should be performed to confirm true myocardial injury.

Adjuvant Radiotherapy in Atypical Meningioma: Are the Risks Worth the Benefit?

PURPOSE/OBJECTIVE(S)

Adjuvant radiotherapy (RT) improves progression-free survival (PFS) in atypical meningiomas. Herein, we assess whether the treatment-related acute and long-term toxicity of upfront RT in atypical meningioma patients versus surveillance merits the PFS benefit.

MATERIALS/METHODS

In our prior single institution retrospective study of 230 patients with resected intracranial atypical meningiomas between 2000-2015, adjuvant RT was associated with a significantly lower risk of progression/recurrence compared to surveillance (HR = 0.21 [95% CI 0.11-0.41]; p<0.01), with 36% of surveillance patients eventually requiring salvage RT. In the current study, the acute (≤6 months) and long term (>6 months) RT-related toxicities from the same patient cohort for those who received adjuvant RT (n = 51) were evaluated and compared to those who received salvage RT (n = 64) in the surveillance group. Additionally, overall treatment-related toxicity at time of last follow up was obtained for comparison between the adjuvant RT (n = 51) vs surveillance (n = 179) group. All toxicities were graded per CTCAE v5.0. Kaplan-Meier analysis was used to calculate the cumulative incidence of toxicities; Pearson's chi-squared and log-rank test were used for comparison.

RESULTS

Adjuvant RT as compared to salvage RT was generally associated with greater RT-related toxicities both in the acute (90% vs 69%, p = 0.006) and long term (57% vs 33%, p = 0.010). While there was no significant difference in grade 3-4 acute toxicities, long term grade 3-4 toxicities (including headache, seizure, vision loss, neuromotor deficit, and neurocognitive deficit) were present in 14% of adjuvant vs 3% of salvage RT group (p = 0.035). Radionecrosis occurred in 18% of adjuvant RT vs 8% of salvage RT group (p = 0.11). Between adjuvant RT vs surveillance groups, any-treatment related toxicity at last follow up was greater with adjuvant RT (31% vs 15%; p = 0.006), with trend towards greater grade 3-4 toxicities (including headache, vision loss, neuromotor deficit, neurocognitive deficit, and cerebral edema) as well (8% vs 3%; p = 0.101). Cumulative incidence of treatment-related neuromotor deficit (any grade) was significantly greater in the adjuvant RT vs surveillance group with 14% vs 2% at 10 years (p = 0.004). There was no difference in rate of cerebrovascular accident between adjuvant RT (6%) vs surveillance (4%) groups (p = 0.83).

CONCLUSION

Adjuvant RT for patients with atypical meningioma was associated with greater acute and long-term treatment toxicities. Potential RT-related toxicity and impact on quality-of-life should thus be carefully weighed against the tumor control benefit of RT in deciding the optimal use and timing of RT.

Docosahexaenoic acid (DHA) intake estimated from a 7-question survey identifies pregnancies most likely to benefit from high-dose DHA supplementation

BACKGROUND

Two randomized trials found women with low blood docosahexaenoic acid (DHA; an omega 3 fatty acid) had fewer early preterm births (<34 weeks gestation) if they were assigned to high dose DHA supplementation, however, there is currently no capacity for clinicians who care for pregnancies to obtain a blood assessment of DHA. Determining a way to identify women with low DHA intake whose risk could be lowered by high dose DHA supplementation is desired.

OBJECTIVE

To determine if assessing DHA intake can identify pregnancies that benefit from high dose DHA supplementation.

STUDY DESIGN

This secondary analysis used birth data from 1310 pregnant women who completed a 7-question food frequency questionnaire (DHA-FFQ) at 16.8 ± 2.5 weeks gestation that is validated to assess DHA status. They were then randomly assigned to a standard (200 mg/day) or high dose (800 or 1000 mg/day) DHA supplement for the remainder of pregnancy. Bayesian logistic regressions were fitted for early preterm birth and preterm birth as a function of DHA intake and assigned DHA dose.

RESULTS

Participants who consumed less than 150 mg/day DHA prior to 20 weeks' gestation (n = 810/1310, 58.1%) had a lower Bayesian posterior probability (pp) of early preterm birth if they were assigned to high dose DHA supplementation (1.4% vs 3.9%, pp = 0.99). The effect on preterm birth (<37 weeks) was also significant (11.3% vs 14.8%, pp = 0.97).

CONCLUSION

The DHA-FFQ can identify pregnancies that will benefit most from high dose DHA supplementation and reduce the risk of preterm birth. The DHA-FFQ is low burden to providers and patients and could be easily implemented in obstetrical practice.

Spatio-temporal coupling of RMS errors in laser amplification

We developed a theoretical model for the relationship between the input and amplified laser beams of energy stability and spatial uniformity in the amplification process. 10 Hz, 8 ns, 1064 nm Nd:YAG Q-switched resonator with Nd:YAG main amplifier was employed for the experiment. The theoretical model simulation and Frantz-Nodvik simulation were performed by utilizing the obtained beam image, acquired energy from the experiment, and stored fluence from the gain medium. The result indicated that the fluctuation of the spatial distribution in a single beam influences the stability of temporally distributed energy during the amplification process of the laser beam, thereby improving energy stability.

Development and validation of the HARMS2-AF lifestyle risk score to predict incident AF

Background

Lifestyle risk factors (RFs) are a modifiable target in atrial fibrillation (AF) management. However, the relative contribution of individual lifestyle RFs to AF incidence has not been described.

Purpose

Development and validation of a novel AF-lifestyle risk score to determine AF risk in the general population.

Methods

The UK Biobank (UKB) is a large prospective cohort with outcomes measured &gt;10 years. In the UKB, we performed regression analysis of AF lifestyle RFs which were then evaluated in a multivariable model and a weighted score was developed. Next, the risk score was externally validated in the Framingham Heart Study (FHS) population. Kaplan-Meier estimates ascertained the 10-year risk of AF development.

Results

In the UKB, AF incidence was 5.3% among 302,926 participants, with a median time to AF 7.3 years (IQR 4.3–9.8). Hypertension, sleep apnoea, male sex, age, obesity (BMI&gt;30 kg/m2), alcohol and smoking were predictive variables (all p&lt;0.001); physical inactivity (OR 1.02,95% CI 0.97–1.10, p=0.3), diabetes (OR 0.98,95% CI 0.91–1.06, p=0.2) and BMI 27–30 kg/m2 (OR 1.02, 95% CI 0.97–1.07, p=0.424) were not significant. The HARMS2-AF score (Figure 1) had similar predictive performance (AUC=0.782, LogLoss 0.178, Brier Score 0.046) to the unweighted regression model (AUC 0.808) in the UKB. Validation in the FHS (AF incidence 6.7% of 7206 participants) maintained excellent predictive performance with an AUC of 0.747 (95% CI 0.724–0.769, Figure 2). A higher HARMS2-AF score (&gt;5 points) was associated with a heightened 10-year AF risk (score 5–9: OR 9.35, score 10–14: OR 33.34).

Conclusions

The HARMS2-AF score is a novel lifestyle risk score which may help identify individuals at risk of AF and assists in general population screening.

Funding Acknowledgement

Type of funding sources: None.

Catheter ablation in atrial fibrillation and heart failure with preserved ejection fraction improves peak pulmonary capillary wedge pressure, exercise capacity and quality of life: RCT STALL HFpEF

Introduction

Atrial fibrillation (AF) frequently accompanies heart failure with preserved ejection fraction (HFpEF). AF exacerbates HFpEF through adverse haemodynamic effects. In turn, HFpEF promotes AF through adverse left atrial remodelling. Observational data suggest sinus rhythm restoration improves outcomes in patients with AF and HFpEF. However, there are no randomised data examining the effects of rhythm control with catheter-based AF ablation on HFpEF outcomes.

Purpose

To compare the effects of AF ablation versus usual medical therapy on markers of HFpEF severity, including exercise haemodynamics, natriuretic peptide levels and patient symptoms.

Methods

Patients with symptomatic AF and HFpEF underwent exercise right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET). HFpEF diagnosis was based on left ventricular ejection fraction (LVEF) ≥50%, elevated natriuretic peptide and echocardiographic diastolic impairment. HFpEF was confirmed on exercise RHC based on peak exercise pulmonary capillary wedge pressure (PCWP) of ≥25mmHg. Patients were randomised to AF ablation versus medical therapy, with investigations repeated at 6 months. The primary outcome was change in PCWP on follow-up.

Results

31 patients aged 66.1±7.5 years were randomized to AF ablation (16) versus medical therapy (15), with 51.6% female and 80.6% persistent AF. Baseline characteristics were comparable across groups. Paired analyses of ablation cohort showed significant reductions in peak PCWP (29.6±3.7 vs 25.9±4.6 mmHg, p&lt;0.01), PCWP indexed for workload (39.0±57.9 vs 33.0±50.5 mmHg/W/kg, p&lt;0.01), and BNP (146.2±80.5 vs 82.2±75.4 pg/mL, p=0.01); and increased resting cardiac output (4.6±0.9 vs 5.6±1.2 L/min, p=0.01), peak cardiac output (9.6±4.2 vs 10.4±3.7 L/min, p=0.02), peak (30s averaged) VO2 (1875.1±759.2 vs 2193.7±878.1 mL/min, p&lt;0.01), peak absolute VO2 (1937.3±739.3 vs 2216.3±861.9 mL/min, p&lt;0.01), peak (30s averaged) relative VO2 (19.4±5.9 vs 22.9±7.4 ml/kg/min) and peak workload (162.0±81.1 vs 184.4±83.4 W, p&lt;0.01). Quality of life scores improved: AFEQT (45.3±20.9 vs 75±20.7, p&lt;0.01) and MLHF (53±23.3 vs 17.5±22.8, p&lt;0.01). Reversal of HFpEF by PCWP criteria occurred in 31.2% following AF ablation, and 50% among those free from arrhythmia recurrence. In the medical arm, there were no significant differences in RHC, CPET, and natriuretic peptide outcomes on follow-up versus baseline. Repeated measures mixed ANOVA testing showed significant time-randomisation interaction on peak VO2, absolute peak VO2, peak relative VO2, AFEQT/ MLHF scores, suggesting that significant improvements in these parameters were related to AF ablation.

Conclusion

In patients with concomitant AF and HFpEF, AF ablation improves invasive exercise haemodynamic parameters, increases exercise capacity, and enhances quality of life. Successful AF ablation may reverse the clinical syndrome of HFpEF in a subset of cases.

Funding Acknowledgement

Type of funding sources: None.

Clinical risk prediction for left atrial appendage thrombus among patients with atrial fibrillation

Background

Exclusion of left atrial appendage thrombus (LAAT) by transoesophageal echocardiography (TOE) is recommended in patients with inadequate anticoagulation prior to direct cardioversion (DCR) or catheter ablation for atrial fibrillation/flutter (AF/AFL). LAAT risk factors in this population remain poorly defined.

Purpose

Determine LAAT predictors in AF/AFL patients undergoing pre-procedural TOE.

Methods

We evaluated available clinical and transthoracic echocardiographic (TTE) parameters in AF/AFL patients undergoing TOE between 1999–2022 in our institution in Melbourne, Australia. Regression analysis identified predictors of LAAT, which were applied to a weighted score developed in the derivation cohort (70%) and validated in the remaining 30%.

Results

Of 627 patients (age 62±12 years, 27% female, AF 84%,AFL 16%, left ventricular ejection fraction (LVEF) 44±20%), 24% had LAAT and 13.8% dense spontaneous echo contrast precluding DCR. Anticoagulation was NOAC 56.5%, warfarin 32.1% and none in 11.4%. In the LAAT cohort, thrombus resolution occurred in 39% on serial transoesophageal imaging with a median time to resolution of 131 days (IQR 54–398).

Diabetes (p=0.004), prior stroke (p=0.009), coronary disease (p=0.015), renal impairment (p&lt;0.001) and CHADS2VASc &gt;2 (73% vs. 55%, p&lt;0.001) were higher in the LAAT cohort. Age (p=0.093), gender (p=0.689), BMI (p=0.828), anticoagulant type (p=0.316) and diabetes (p=0.107) were not univariate predictors, whereas anticoagulation duration (&lt;30 days), creatinine and TTE markers of remodeling (LVEF, LAVI, RVSP and TAPSE) were independent predictors on univariate and multivariate regression; CHADS2VASc was not significant after adjustment (p=0.090). The weighted risk model included continuous (age, creatinine, LVEF, LAVI, TAPSE and RVSP) and categorical (anticoagulation duration) variables with excellent predictive performance: AUC 0.872 (95% CI 0.798–0.946), PPV 91%, NPV 70% and accuracy 80%.

Conclusion

A novel LAAT risk model comprising clinical and echocardiographic parameters enhances risk prediction over CHADS2VASc in AF/AFL and may guide the need for pre-procedural TOE imaging.

Funding Acknowledgement

Type of funding sources: None.

Patients and healthcare professionals views on injectables for cardiovascular disease

Introduction

Injectable medicines are increasingly used to manage risk factors for cardiovascular (CV) events, such as PCSK-9 inhibitors in dyslipidaemia and GLP-1 agonists in diabetes. However, there is a paucity of data around the administrative and clinical practicalities when using these injectables, and limited information on patient and healthcare professionals' perceptions.

Purpose

To identify the facilitators and barriers on the use of injectable therapies with CV benefits by undertaking interviews with patients, caregivers and healthcare professionals (HCPs).

Methods

Interviews were conducted via telephone and using MS Teams due to Covid-19 restrictions in the United Kingdom (London and Leeds) and Italy (Rome and Milan) in 2021. Coding was undertaken using NVivo and thematic analysis performed.

Results

A total of 56 patients were interviewed: 30 in the U.K. (mean age 66 yrs, 60% male) and 26 patients in Italy (mean age 63 yrs, 80% male) and 11 caregivers (mean age 59 yrs, 73% female). A total of 38 HCPs were interviewed, 19 in each country and composed of physicians (n=18), pharmacists (n=10), nurses (n=9) and pharmacy technician (n=1). Three distinct themes were identified: (i) Organisational and governance issues - relating to prescribing restrictions and availability of the drugs locally (PCSK9i are initiated and supplied from hospitals) and lack of communication between hospital and primary care setting; (ii) Clinical issues around HCPs' skills and experience - including: lack of experience with these injectables, lack of time to provide education to patients and caregivers, therapeutic inertia (HCPs not adopting a change in practice despite the evidence or due to bureaucratic restrictions) as well as lack of knowledge on long-term effects, and finally (iii) Patient-related issues - relating to behaviours and beliefs such as reluctance about using injectable therapies, and lack of education about these injectables in terms of indications/clinical benefits for use. Despite some differences in the prescribing of these injectables in the two countries, the analysis captured similar facilitators and barriers. Facilitators included prior use of injectables (e.g. insulin), and the ability to reach a clinical target of lower cholesterol by having just a “one shot”. HCPs stated that access to rapid pathology tests would aid uptake of injectables with CV benefit as well as having educational tools on these injectables in practice.

Conclusion

This qualitative study identified barriers to initiation, continuation, and adherence with injectable therapies with CV benefits but also highlighted areas where changes can be made especially around education and support for patients and HCPs.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): ACNAP education grant. Sponsored by Amgem and Novo Nordisk