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1.
Nanotechnology ; 35(30)2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38653214

RESUMO

Graphene oxide (GO)-based membranes hold significant promise for applications ranging from energy storage to protective coatings, to saline water and produced water treatment, owing to their chemical stability and unique barrier properties achieving a high selectivity for water permeation. However, unmodified GO membranes are not stable when submerged in liquid water, creating challenges with their commercial utilization in aqueous filtration and pervaporation applications. To mitigate this, we develop an approach to modify GO membranes through a combination of low temperature thermal reduction and metal cation crosslinking. We demonstrate that Zn2+-rGO and Fe3+-rGO membranes had the highest permeation flux of 8.3 ± 1.5 l m-2h-1and 7.0 ± 0.4 l m-2h-1, for saline water separation, respectively, when thermally reduced after metal cross-linking; These membranes maintained a high flux of 7.5 ± 0.7 l m-2h-1, and 5.5 ± 0.3 l m-2h-1for produced water separation, respectively. All the membranes had a salt rejection higher than 99%. Fe3+crosslinked membranes presented the highest organic solute rejections for produced water of 69%. Moreover, long term pervaporation testing was done for the Zn2+-rGO membrane for 12 h, and only a minor drop of 6% in permeation flux was observed, while Zn2+-GO had a drop of 24%. Both modifiers significantly enhanced the stability with Fe3+-rGO membranes displaying the highest mechanical abrasion resistance of 95% compared to non-reduced and non-crosslinked GO. Improved stability for all samples also led to higher selectivity to water over organic contaminants and only slightly reduced water flux across the membrane.

2.
Artigo em Inglês | MEDLINE | ID: mdl-37600156

RESUMO

Aims: In patients with a low AF burden and long periods of sinus rhythm, 'pill-in-the-pocket' oral anticoagulation (OAC) may, taken as needed in response to AF episodes, offer the same thromboembolic protection as continuous, life-long OAC, while reducing bleeding complications at the same time. The purpose of this study is to systematically summarise available evidence pertaining to the feasibility, safety and efficacy of pill-in-the-pocket OAC. Methods: Medline and Embase were searched from inception to July 2022 for studies adopting a pill-in-the-pocket OAC strategy in AF patients guided by daily rhythm monitoring (PROSPERO/CRD42020209564). Outcomes of interest were extracted and event rates per patient-years of follow-up were calculated. A random effects model was used for pooled estimates. Results: Eight studies were included (711 patients). Daily rhythm monitoring was continuous in six studies and intermittent in two (pulse checks or smartphone single-lead electrocardiograms were used). Anticoagulation criteria varied across studies, reflecting the uncertainty regarding the AF burden that warrants anticoagulation. The mean time from AF meeting OAC criteria to its initiation was not reported. Adopting pill-in-the-pocket OAC led to 390 (54.7%) patients stopping OAC, 85 (12.0%) patients taking pill-in-the-pocket OAC and 237 (33.3%) patients remaining on or returning to continuous OAC. Overall, annualised ischaemic stroke and major bleeding rates per patient-year of follow-up were low at 0.005 (95% CI [0.002-0.012]) and 0.024 (95% CI [0.013-0.043]), respectively. Conclusion: Current evidence, although encouraging, is insufficient to inform practice. Additional studies are required to improve our understanding of the relationships between AF burden and thromboembolic risk to help define anticoagulation criteria and appropriate monitoring strategies.

3.
Artigo em Inglês | MEDLINE | ID: mdl-37427305

RESUMO

Prevention of sudden death using ICDs requires the reliable delivery of a high-energy shock to successfully terminate VF. Until more recently, the device implant procedure included conducting defibrillation threshold (DFT) testing involving VF induction and shock delivery to ensure efficacy. Large clinical trials, including SIMPLE and NORDIC ICD, have subsequently demonstrated that this is unnecessary, with a practice of omitting DFT testing having no impact on subsequent clinical outcomes. However, these studies specifically excluded patients requiring devices implanted on the right side, in whom the shock vector is significantly different and smaller studies suggest a higher DFT. In this review, the data regarding the use of DFT testing, focusing on right-sided implants, and the results of a survey of current UK practice are presented. In addition, a strategy of shared decision-making when it comes to deciding on the use of DFT testing during right-sided ICD implant procedures is proposed.

4.
J Physiol ; 601(18): 4013-4032, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37475475

RESUMO

The best pharmacological treatment for each atrial fibrillation (AF) patient is unclear. We aim to exploit AF simulations in 800 virtual atria to identify key patient characteristics that guide the optimal selection of anti-arrhythmic drugs. The virtual cohort considered variability in electrophysiology and low voltage areas (LVA) and was developed and validated against experimental and clinical data from ionic currents to ECG. AF sustained in 494 (62%) atria, with large inward rectifier K+ current (IK1 ) and Na+ /K+ pump (INaK ) densities (IK1 0.11 ± 0.03 vs. 0.07 ± 0.03 S mF-1 ; INaK 0.68 ± 0.15 vs. 0.38 ± 26 S mF-1 ; sustained vs. un-sustained AF). In severely remodelled left atrium, with LVA extensions of more than 40% in the posterior wall, higher IK1 (median density 0.12 ± 0.02 S mF-1 ) was required for AF maintenance, and rotors localized in healthy right atrium. For lower LVA extensions, rotors could also anchor to LVA, in atria presenting short refractoriness (median L-type Ca2+ current, ICaL , density 0.08 ± 0.03 S mF-1 ). This atrial refractoriness, modulated by ICaL and fast Na+ current (INa ), determined pharmacological treatment success for both small and large LVA. Vernakalant was effective in atria presenting long refractoriness (median ICaL density 0.13 ± 0.05 S mF-1 ). For short refractoriness, atria with high INa (median density 8.92 ± 2.59 S mF-1 ) responded more favourably to amiodarone than flecainide, and the opposite was found in atria with low INa (median density 5.33 ± 1.41 S mF-1 ). In silico drug trials in 800 human atria identify inward currents as critical for optimal stratification of AF patient to pharmacological treatment and, together with the left atrial LVA extension, for accurately phenotyping AF dynamics. KEY POINTS: Atrial fibrillation (AF) maintenance is facilitated by small L-type Ca2+ current (ICaL ) and large inward rectifier K+ current (IK1 ) and Na+ /K+ pump. In severely remodelled left atrium, with low voltage areas (LVA) covering more than 40% of the posterior wall, sustained AF requires higher IK1 and rotors localize in healthy right atrium. For lower LVA extensions, rotors can also anchor to LVA, if the atria present short refractoriness (low ICaL ) Vernakalant is effective in atria presenting long refractoriness (high ICaL ). For short refractoriness, atria with fast Na+ current (INa ) up-regulation respond more favourably to amiodarone than flecainide, and the opposite is found in atria with low INa . The inward currents (ICaL and INa ) are critical for optimal stratification of AF patient to pharmacological treatment and, together with the left atrial LVA extension, for accurately phenotyping AF dynamics.


Assuntos
Amiodarona , Fibrilação Atrial , Humanos , Fibrilação Atrial/tratamento farmacológico , Flecainida/farmacologia , Flecainida/uso terapêutico , Átrios do Coração , Amiodarona/farmacologia , Amiodarona/uso terapêutico , Potenciais de Ação/fisiologia
5.
J Colloid Interface Sci ; 648: 129-140, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37295365

RESUMO

HYPOTHESIS: Coating approaches which trap nanoparticles at an interface have become popular for depositing single-layer films from nanoparticle dispersions. Past efforts concluded that concentration and aspect ratio dominate the impact on aggregation state of nanospheres and nanorods at an interface. Although few works have explored the clustering behaviour of atomically thin, two-dimensional materials, we hypothesize that nanosheet concentration is the dominant factor leading to a particular cluster structure and that this local structure impacts the quality of densified Langmuir films. EXPERIMENTS: We systematically studied cluster structures and Langmuir film morphologies of three different nanosheets, namely chemically exfoliated molybdenum disulfide, graphene oxide and reduced graphene oxide. FINDINGS: We observe cluster structure transitions from island-like domains to more linear networks in all materials as dispersion concentration is reduced. Despite differences in material properties and morphologies, we obtained the same overall correlation between sheet number density (A/V) in the spreading dispersion and cluster fractal structure (df) is observed, with reduced graphene oxide sheets showing a slight delay upon transitioning into a lower-density cluster. Regardless of assembly method, we found that cluster structure impacts the attainable density of transferred Langmuir films. A two-stage clustering mechanism is supported by by considering the spreading profile of solvents and an analysis of interparticle forces at the air-water interface.

6.
Open Heart ; 10(1)2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37130658

RESUMO

OBJECTIVE: The training of interventional cardiologists (ICs), non-interventional cardiologists (NICs) and cardiac surgeons (CSs) differs, and this may be reflected in their interpretation of invasive coronary angiography (ICA) and management plan. Availability of systematic coronary physiology might result in more homogeneous interpretation and management strategy compared with ICA alone. METHODS: 150 coronary angiograms from patients with stable chest pain were presented independently to three NICs, three ICs and three CSs. By consensus, each group graded (1) coronary disease severity and (2) management plan, using options: (a) optimal medical therapy alone, (b) percutaneous coronary intervention, (c) coronary artery bypass graft or (d) more investigation required. Each group was then provided with fractional flow reserve (FFR) from all major vessels and asked to repeat the analysis. RESULTS: There was only 'fair' level of agreement of management plan among ICs, NICs and CSs (kappa 0.351, 95% CI 0.295-0.408, p<0.001) based on ICA alone (complete agreement in 35% of cases), which almost doubled to 'good' level (kappa 0.635, 95% CI 0.572-0.697, p<0.001) when comprehensive FFR was available (complete agreement in 66% of cases). Overall, the consensus management plan changed in 36.7%, 52% and 37.3% of cases for ICs, NICs and CSs, respectively, when FFR data were available. CONCLUSIONS: Compared with ICA alone, the availability of systematic FFR of all major coronary arteries produced a significantly more concordant interpretation and more homogeneous management plan among IC, NIC and CS specialists. Comprehensive physiological assessment may be of value in routine care for Heart Team decision-making. TRIAL REGISTRATION NUMBER: NCT01070771.


Assuntos
Doença da Artéria Coronariana , Reserva Fracionada de Fluxo Miocárdico , Humanos , Angiografia Coronária , Reserva Fracionada de Fluxo Miocárdico/fisiologia , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/terapia , Coração , Ponte de Artéria Coronária
7.
Clin Case Rep ; 11(6): e7418, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37255614

RESUMO

Key Clinical Message: Scurvy is uncommon in the developed world, and clinical presentation may mimic other pathologic states. A thorough social and dietary history is essential to identifying patients at risk of vitamin C deficiency, which can then be easily treated. Abstract: Scurvy is a disease of defective collagen synthesis that is characterized by easy bruising, gingival hemorrhages, poor wound healing, fatigue, and arthralgias. It is caused by dietary deficiency of vitamin C. This is the case of a patient with multiple risk factors for malnutrition who was diagnosed with scurvy.

8.
Nanotechnology ; 34(41)2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37257435

RESUMO

Among the many recently developed photo-catalytic materials, graphitic carbon nitride (g-C3N4) shows great promise as a catalytic material for water splitting, hydrogen generation, and related catalytic applications. Herein, synthesized bulk g-C3N4is simply irradiated under a 35 fs pulse at mixed photon energies (800 nm and its second harmonic). g-C3N4was synthesized from melamine following a facile thermal polymerization procedure. The prepared material was introduced, in an aqueous environment, to the femtosecond laser for various lengths of time. The treated material demonstrates a significant increase in surface area, relative to the untreated samples, indicating that irradiation is a successful method for exfoliation. The subsequent characterization reveals that the mixed irradiation process drives significant defect generation and sheet growth, which is not seen under 800 nm irradiation. Extended mixed irradiation results in 4 nm thick nanosheets with lateral dimensions 4× that of the bulk material. The treated material shows improved dye absorption/removal. This novel method of defect generation and nanosheet growth shows great potential as a g-C3N4pre-treatment method for co-catalytic applications. Herein it is shown that femtosecond laser irradiation drives exfoliation beyond 100 nm particle sizes, and sheet-like morphologies under extended irradiation, which must be taken into account when using this method to improve material performance.

9.
Sci Rep ; 13(1): 7718, 2023 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-37173351

RESUMO

The concept of truth is at the core of science, journalism, law, and many other pillars of modern society. Yet, given the imprecision of natural language, deciding what information should count as true is no easy task, even with access to the ground truth. How do people decide whether a given claim of fact qualifies as true or false? Across two studies (N = 1181; 16,248 observations), participants saw claims of fact alongside the ground truth about those claims. Participants classified each claim as true or false. Although participants knew precisely how accurate the claims were, participants classified claims as false more often when they judged the information source to be intending to deceive (versus inform) their audience, and classified claims as true more often when they judged the information source to be intending to provide an approximate (versus precise) account. These results suggest that, even if people have access to the same set of facts, they might disagree about the truth of claims if they attribute discrepant intentions to information sources. Such findings may shed light on the robust and persistent disagreements over claims of fact that have arisen in the "post-truth era".


Assuntos
Fonte de Informação , Intenção , Humanos
10.
Heart Rhythm ; 20(7): 1018-1025, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37019166

RESUMO

BACKGROUND: Slow pathway (SP) mapping and modification can be challenging in patients with persistent left superior vena cava (PLSVC) due to anatomic variance of the Koch triangle (KT) and coronary sinus (CS) dilation. Studies using detailed 3-dimensional (3D) electroanatomic mapping (EAM) to investigate conduction characteristics and guide ablation targets in this condition are lacking. OBJECTIVES: The purpose of this study was to describe a novel technique of SP mapping and ablation in sinus rhythm using 3D EAM in patients with PLSVC after validation in a cohort with normal CS anatomy. METHODS: Seven patients with PLSVC and dual atrioventricular (AV) nodal physiology who underwent SP modification with the use of 3D EAM were included. Twenty-one normal heart patients with AV nodal reentrant tachycardias formed the validation group. High-resolution, ultra-high-density local activation timing mapping of the right atrial septum and proximal CS in sinus rhythm was performed. RESULTS: SP ablation targets were consistently identified by an area in the right atrial septum with the latest activation time and multicomponent atrial electrogram adjacent to a region with isochronal crowding (deceleration zone). In PLSVC patients, these targets were located at or within 1 cm of the midanterior CS ostium. Ablation in this area led to successful SP modification, reaching standard clinical endpoints with a median of 43 seconds of radiofrequency energy or 14 minutes of cryoablation without complications. CONCLUSION: High-resolution activation mapping of the KT in sinus rhythm can facilitate localization and safe SP ablation in patients with PLSVC.


Assuntos
Ablação por Cateter , Veia Cava Superior Esquerda Persistente , Taquicardia por Reentrada no Nó Atrioventricular , Humanos , Veia Cava Superior/cirurgia , Ablação por Cateter/métodos , Fascículo Atrioventricular , Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Taquicardia por Reentrada no Nó Atrioventricular/cirurgia
11.
ACS Appl Mater Interfaces ; 15(8): 10570-10584, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36795101

RESUMO

The use of inexpensive and widely available CO2 lasers to selectively irradiate polymer films and form a graphene foam, termed laser-induced graphene (LIG), has incited significant research attention. The simple and rapid nature of the approach and the high conductivity and porosity of LIG have motivated its widespread application in electrochemical energy storage devices such as batteries and supercapacitors. However, nearly all high-performance LIG-based supercapacitors reported to date are prepared from costly, petroleum-based polyimide (Kapton, PI). Herein, we demonstrate that incorporating microparticles of inexpensive, non-toxic, and widely abundant sodium salts such as NaCl and Na2SO4 into poly(furfuryl alcohol) (PFA) resins enables the formation of high-performance LIG. The embedded particles aid in carbonization and act as a template for pore formation. While increasing both the carbon yield and surface area of the electrodes, the salt also dopes the LIG formed with S or Cl. The combination of these effects results in a two- to four-order-of-magnitude increase in device areal capacitance, from 8 µF/cm2 for PFA/no salt at 5 mV/s to up to 80 mF/cm2 for some PFA/20% Na2SO4 samples at 0.05 mA/cm2, significantly higher than that of PI-based devices and most other LIG precursors.

12.
J Clin Med ; 13(1)2023 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-38202148

RESUMO

Hereditary hemorrhagic telangiectasia (HHT) is a hereditary disease characterized by recurrent epistaxis, mucocutaneous telangiectasias, and visceral arteriovenous malformations. Multiple genetic mutations have been linked to this rare disease, including ENG, ALK1 (ACVRL1), and MADH4. Pulmonary hypertension is a potential complication of HHT, with the most common phenotypes being World Health Organization (WHO) group 1 heritable pulmonary arterial hypertension (PAH), which is typically associated with ALK1 mutation; WHO group 2 pulmonary hypertension due to high output heart failure from hepatic arteriovenous malformations and/or anemia; and WHO group 2 due to high pulmonary artery wedge pressure. There is scarce evidence to help guide treatment of heritable PAH in HHT, and observational literature suggests that patients with HHT and heritable PAH have a worse prognosis compared to patients with idiopathic PAH. We describe the diagnosis, pulmonary hemodynamics, and detailed treatment courses of three patients with ALK1-associated HHT and PAH, who all exhibited objective clinical improvement with parenteral prostacyclins and oral agents.

13.
Heart ; 108(24): 1979-1985, 2022 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-35948408

RESUMO

OBJECTIVES: For patients with a reduced left ventricular ejection fraction (LVEF) heart failure with reduced ejection fraction (HFrEF) and iron deficiency, administration of intravenous iron improves symptoms, exercise capacity and may in the following 12 months, reduce hospitalisations for heart failure. The Effectiveness of Intravenous iron treatment versus standard care in patients with heart failure and iron deficiency (IRONMAN) trial evaluated whether the benefits of intravenous iron persist in the longer term and impact on morbidity and mortality. METHODS: IRONMAN is a prospective, randomised, open-label, blinded endpoint (PROBE) event-driven trial. Patients aged ≥18 years with HFrEF (LVEF ≤45%) and evidence of iron deficiency (ferritin <100 µg/L and/or TSAT <20%) were enrolled if they had either a current or recent hospitalisation for heart failure or elevated plasma concentrations of a natriuretic peptide. Participants were randomised to receive, or not to receive, intravenous ferric derisomaltose in addition to guideline-recommended therapy for HFrEF. Every 4 months, intravenous iron was administered if either ferritin was <100 µg/L or, provided ferritin was ≤400 µg/L, TSAT was <25%. The primary endpoint is a composite of total hospitalisations for heart failure and cardiovascular death. Hospitalisation and deaths due to infection are safety endpoints. RESULTS: Trial recruitment was completed across 70 UK hospital sites in October 2021. Participants were followed until the end of March 2022. We plan to report the results by November 2022. CONCLUSIONS: IRONMAN will determine whether repeated doses of intravenous ferric derisomaltose are beneficial and safe for the long-term treatment of a broad range of patients with HFrEF and iron deficiency. TRIAL REGISTRATION NUMBER: NCT02642562.


Assuntos
Insuficiência Cardíaca Sistólica , Insuficiência Cardíaca , Deficiências de Ferro , Humanos , Adolescente , Adulto , Volume Sistólico , Ferro , Estudos Prospectivos , Função Ventricular Esquerda , Ferritinas/uso terapêutico
14.
Artigo em Inglês | MEDLINE | ID: mdl-35835888

RESUMO

The implantable cardioverter-defibrillator (ICD) is a proven treatment for preventing sudden cardiac death. Transvenous leads are associated with significant mortality and morbidity, and the subcutaneous ICD (S-ICD) addresses this. However, it is not without limitations, in particular the absence of anti-tachycardia pacing. The decision of which device is most suitable for an individual patient is often complex. Here, we review the relative merits and weaknesses of both the transvenous and S-ICD. We summarise the available evidence for each device in particular patient cohorts, namely: ischaemic and non-ischaemic cardiomyopathy, idiopathic ventricular fibrillation, Brugada syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy, and hypertrophic cardiomyopathy.

15.
Arrhythm Electrophysiol Rev ; 11: e06, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35755327

RESUMO

Results from catheter ablation for persistent AF are suboptimal, with no strategy other than pulmonary vein isolation showing clear benefit. Recently employed empirical strategies beyond pulmonary vein isolation involve widespread atrial ablation in all patients and do not take into account patient-specific differences in AF mechanisms or phenotype. Charge density mapping using the non-contact AcQMap system (Acutus Medical) allows visualisation of whole-chamber activation during AF and reveals localised patterns of complex activation thought to represent important mechanisms for AF maintenance that can be targeted with focal ablation. In this review, the authors outline the fundamentals of this technology, the initial data exploring the mechanistic role of activation patterns seen and the application to ablation of persistent AF.

16.
J Am Heart Assoc ; 11(11): e021166, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35621197

RESUMO

Background Adenosine shortens action potential duration and refractoriness and provokes atrial fibrillation. This study aimed to evaluate the effect of adenosine on mechanisms of wavefront propagation during atrial fibrillation. Methods and Results The study included 22 patients undergoing catheter ablation for persistent atrial fibrillation. Left atrial mapping was performed using the AcQMap charge density system before and after administration of intravenous adenosine at 1 or more of 3 time points during the procedure (before pulmonary vein isolation, after pulmonary vein isolation, and after nonpulmonary vein isolation ablation). Wave-front propagation patterns were evaluated allowing identification and quantification of localized rotational activation (LRA), localized irregular activation, and focal firing. Additional signal processing was performed to identify phase singularities and calculate global atrial fibrillation cycle length and dominant frequency. A total of 35 paired maps were analyzed. Adenosine shortened mean atrial fibrillation cycle length from 181.7±14.3 to 165.1±16.3, (mean difference 16.6 ms; 95% CI, 11.3-21.9, P<0.0005) and increased dominant frequency from 6.0±0.7 Hz to 6.6±0.8 Hz (95% CI, 0.4-0.9, P<0.0005). This was associated with a 50% increase in the number of LRA occurrences (16.1±7.6-24.2±8.1; mean difference 8.1, 95% CI, 4.1-12, P<0.0005) as well as a 20% increase in the number of phase singularities detected (30.1±7.8-36.6±9.3; mean difference 6.5; 95% CI, 2.6-10.0, P=0.002). The percentage of left atrial surface area with LRA increased with adenosine and 42 of 70 zones (60%) with highest density of LRA coincided with high density LRA zones at baseline with only 28% stable across multiple maps. Conclusions Adenosine accelerates atrial fibrillation and promotes rotational activation patterns with no impact on focal activation. There is little evidence that rotational activation seen with adenosine represents promising targets for ablation aimed at sites of stable arrhythmogenic sources in the left atrium.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Veias Pulmonares , Adenosina , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/cirurgia , Ablação por Cateter/métodos , Técnicas Eletrofisiológicas Cardíacas , Átrios do Coração , Frequência Cardíaca , Humanos , Veias Pulmonares/cirurgia , Resultado do Tratamento
17.
ACS Appl Mater Interfaces ; 14(8): 10363-10372, 2022 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-35175023

RESUMO

Due to its formidably high theoretical capacity (3590 mAh/g at room temperature), silicon (Si) is expected to replace graphite as the dominant anode for higher energy density lithium (Li)-ion batteries. However, stability issues stemming from silicon's significant volume expansion (∼300%) upon lithiation have slowed down commercialization. Herein, we report the design of a scalable process to engineer core-shell structures capable of buffering this volume expansion, which utilize a core made up of a poly(ethylene oxide)-carboxymethyl cellulose hydrogel and silicon protected by a crumpled graphene shell. The volume expansion of the hydrogel upon exposure to water creates a void space between the Si-Si and Si-rGO interfaces within the core when the gel dries. Unlike sacrificial spacers, the dehydrated hydrogel remains in the core and acts as an elastic Li-ion conductor, which improves the stability and high rate performance. The optimized composite electrodes retain ∼81.7% of their initial capacity (1055 mAh/(grGO+gel+Si)) after 320 cycles when an active material loading of 1 mg/cm2 is used. At more practical mass loadings (2.5 mg/cm2), the electrodes achieve 2.04 mAh/cm2 and retain 79% of this capacity after 200 cycles against a lithium half-cell. Full cells assembled using a lithium ion phosphate cathode lose only 6.7% of their initial capacity over 100 cycles, demonstrating the potential of this nanocomposite anode for use in next-generation Li-ion batteries.

18.
Langmuir ; 38(1): 531-540, 2022 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-34978199

RESUMO

Most ionic liquids (ILs) are not surface-active and cannot, alone, be directed to assemble at surfaces─despite their potential as nonvolatile structure-directing agents and use as advanced materials in a multitude of applications. In this work, we investigate aqueous systems of common nonionic surfactants (Triton X-100 and Tween 20), which we use to solubilize 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The resulting solution of mixed micelle leads to spontaneous adsorption of the IL/surfactant complex onto graphene oxide (GO) surfaces, forming a compact film. Adsorption isotherms generated by fluorescence labeling of the IL and surfactant phases are used to quantify the extent of adsorption. While sensitive to the GO dispersion concentration, upwards of 3 g IL/g GO adsorb under dilute conditions. Atomic force microscopy is used to show that the adsorbed layer uniformly distributes as an ∼1 nm thick coating (per GO side) as the system reaches the first plateau of a Langmuir-type isotherm. Adsorption beyond this plateau is possible but leads to thicker (>30 nm), inhomogeneous adsorbed layers. Both micellar size in solution and adsorbed layer thickness reduce upon the addition of IL to the surfactant phase, suggesting significant interactions among the materials and nonideal mixing of the components.

19.
Clin Med (Lond) ; 22(1): 77-82, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35078798

RESUMO

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a growing public health epidemic. In the UK, over 1.3 million people have a diagnosis of AF and an estimated 400,000 remain undiagnosed. AF-related strokes account for a quarter of all strokes and, as AF episodes are often asymptomatic, are still often the first manifestation of AF. Early diagnosis and initiation of oral anticoagulation, where appropriate, may prevent some of these thromboembolic strokes. Public Health England is committed to decrease the incidence of AF-related strokes and has sponsored initiatives aimed at improving AF detection by promoting the uptake of wearable technologies. However, the National Institute for Health and Care Excellence (NICE) has not recommended wearable technology in their recent AF diagnosis and management guidelines (NG196). Diagnostic accuracy of single-lead electrocardiography (ECG) generated by the latest iteration of wearable devices is excellent and, in many cases, superior to general practitioner interpretation of the 12-lead ECG. High-quality ECG from wearable devices that unequivocally shows AF can expedite AF detection. Otherwise, there is a real risk of delaying AF diagnosis with the potential of devastating consequences for patients and their families.


Assuntos
Fibrilação Atrial , Acidente Vascular Cerebral , Dispositivos Eletrônicos Vestíveis , Fibrilação Atrial/diagnóstico , Diagnóstico Precoce , Eletrocardiografia , Humanos , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/prevenção & controle
20.
Mater Horiz ; 9(2): 675-687, 2022 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-34781329

RESUMO

Adhesion between similar and dissimilar materials is essential to many biological systems and synthetic materials, devices, and machines. Since the inception of adhesion science more than five decades ago, adhesion to a surface has long been recognized as beyond two-dimensional. Similarly, molecular conformation - the three-dimensional arrangement of atoms in a molecule - is ubiquitous in biology and fundamental to the binding of biomolecules. However, the connection between these concepts, which could link molecular conformation in biology to micro- and macroscopic adhesion in materials science, remains elusive. Herein, we examine this connection by manipulating the molecular conformation of a mussel-inspired universal coating, which imparts a memory for recognizing different hydrogels. This approach leads to significantly (several fold) increased interfacial adhesion between the coating and hydrogels across a broad range of length scales, from molecular to macroscopic. Furthermore, we demonstrate that imparting memory is a general and facile noncovalent approach for enhancing interfacial adhesion that, with suitable energy dissipation, can be used for the bonding of materials.


Assuntos
Hidrogéis , Conformação Molecular , Fenômenos Físicos
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