Dowex Research Articles

Comparison of the toxic effects of polystyrene and sulfonated polystyrene on wheat under cadmium stress

With advances in plastic resource utilization technologies, polystyrene (PS) and sulfonated polystyrene (SPS) microplastics continue to be produced and retained in environmental media, potentially posing greater environmental risks. These plastics, due to their different physicochemical properties, may have different environmental impacts when compounded with other pollutants. The objective of this study was to investigate the combined toxic effects of PS and SPS on wheat using cadmium (Cd) as a background contaminant. The results demonstrated that Cd significantly impeded the normal growth of wheat by disrupting root development. Both PS and SPS exhibited hormesis at low concentrations and promoted wheat growth. Under combined toxicity, PS reduced oxidative stress and promoted the uptake of essential metal elements in wheat. Additionally, KEGG pathway analysis revealed that PS facilitated the repair of Cd-induced blockage of the TCA cycle and glutathione metabolism. However, high concentrations of SPS in combined toxicity not only enhanced oxidative stress and interfered with the uptake of essential metal elements, but also exacerbated the blocked TCA cycle and interfered with pyrimidine metabolism. These differences are related to the different stability (Zeta potential, Hydrodynamic particle size) of the two microplastics in the aquatic environment and their ability to carry heavy metal ions, especially Cd. The results of this study provide important insights into understanding the effects of microplastics on crops in the context of Cd contamination and their environmental and food safety implications.

Stretchable, stabilized‐conductive XNBR/PEDOT:PSS composites based on bottom‐deposited structure

AbstractConductive composites have attracted much attention due to its high conductivity, stretchability, and sensitivity. However, designing conductive composites with relatively stable conductivity under 100% deformation using simple methods remains a challenge. In this work, we employ a simple and straightforward approach to prepare a poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) solution. Based on the conductivity‐optimized PEDOT:PSS (5.95 S/cm), it was combined with carboxylated acrylonitrile‐butadiene rubber latex (XNBRL) to make a flexible conductive material with a unique bottom‐deposited structure. The incorporation of PEDOT:PSS establishes an interconnected conductive network within the XNBR, enhancing both the tensile strength (from 0.31 to 1.24 MPa) and conductivity of the composites. Remarkably, even at 100% strain, the resistance change (ΔR/R0) in the composite remains minimal (<2), demonstrating its exceptional flexibility and high electrical conductivity while maintaining relatively stable resistance during cyclic stretching at 50% deformation. Moreover, the conductive composite can maintain good relative resistance stability under different tensile rates and different strains. This conductive XNBR/PEDOT:PSS composite has promising application prospects in medical devices, which require relatively stable and high conductivity over a relatively large deformation.Highlights A simple method to increase the electrical conductivity of aqueous PEDOT:PSS. Flexible conductive composite with a small change in ΔR/R0. Enables rigid PEDOT to be used in stretchable electronic devices. Construction of 3D conductive network and bottom deposition structure.

Diffusiophoresis in Polymer and Nanoparticle Gradients.

Diffusiophoresis is the movement of the colloidal particles in response to a concentration gradient and can be observed for both electrolyte (e.g., salt) and nonelectrolyte (e.g., glucose) solutes. Here, we investigated the diffusiophoretic behavior of polystyrene (PS-carboxylate surface) microparticles in nonadsorbing charged and uncharged solute gradients [sodium polystyrenesulfonate (NaPSS), polyethylene glycol (PEG), and nanoscale colloidal silica (SiO2)] using a dead-end channel setup. We compared the diffusiophoretic motion in these gradient types with each other and to the case of using a monovalent salt gradient. In each of the nonadsorbing gradient systems (NaPSS, PEG, and SiO2 nanoparticles), the PS particles migrated toward the lower solute concentration. The exclusion distance values (from the initial position) of particles were recorded within the dead-end channel, and it was found that an increase in solute concentration increases exclusion from the main channel. In the polyelectrolyte case, the motion of PS microparticles was reduced by the addition of a background salt due to reduced electrostatic interaction, whereas it remained constant when using the neutral polymer. Particle diffusiophoresis in gradients of polyelectrolytes (charged macromolecules) is quite similar to the behavior when using a PEG gradient (uncharged macromolecule) in the presence of a background electrolyte. Moreover, we observed PS microparticles under different concentrations and molecular weights of PEG gradients. By combining the simulations, we estimated the exclusion length, which was previously proposed to be the order of the polymer radius. Furthermore, the movement of PS microparticles was analyzed in the gradient of silica nanoparticles. The exclusion distance was higher in silica nanoparticle gradients compared to similar-size PEG gradients because silica nanoparticles are charged. The diffusiophoretic transport of the PS microparticles could be simulated by considering the interaction between the PS microparticles and silica nanoparticles.

Flexible Wearable Electrochemical Sensors Based on AuNR/PEDOT:PSS for Simultaneous Monitoring of Levodopa and Uric Acid in Sweat.

As a facile substitute for the invasive technique of blood testing, wearable electrochemical sensors exhibit high potential for the noninvasive and real-time monitoring of biomarkers in human sweat. However, owing to enzyme specificity, the simultaneous detection of multiple biomarkers by enzymatic analysis is challenging. Moreover, sweat accumulation under sensors causes sweat contamination, which hinders real-time biomarker detection from sweat. This study reports the design and fabrication of flexible wearable electrochemical sensors containing a composite comprising Au nanorods (AuNRs) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for the nonenzymatic detection of levodopa (LD) and uric acid (UA) in sweat. Each sensor was integrated with a flexible three-electrode system and a microfluidic patch for sweat sampling. AuNRs immobilized by PEG-doped PEDOT:PSS showed excellent analytical performance for LD and UA at different potentials. Thus, the newly fabricated sensors could detect LD and UA over a broad detection range with high sensitivity and showed a low limit of detection for both species. On-body assessments confirmed the ability of these sensors to simultaneously detect LD and UA in real time. Therefore, this study could open new frontiers in the fabrication of wearable electrochemical sensors for the pharmacokinetic profile tracking of LD and gout management.

One-Pot Electrodeposition of a PANI:PSS/MWCNT Nanocomposite on Carbon Paper for Scalable Determination of Ascorbic Acid

In recent years, there has been growing demand for the monitoring of ascorbic acid levels, especially in underdeveloped populations where ascorbic acid deficiency affects up to 74% of individuals. To facilitate widespread ascorbic acid screening, we have developed a highly scalable conductive polymer nanocomposite with excellent ascorbic acid sensing performance. The material is based on polyaniline, which is deposited in a single step in the presence of polystyrene sulfonate and multi-walled carbon nanotubes onto carbon paper. The modified electrodes take advantage of the electrocatalytic properties of polyaniline toward ascorbic acid, which are boosted by the proton donating polystyrene sulfonate polymer and the high surface area of the multi-walled carbon nanotubes. The morphology and composition of the composite are characterized using field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy and the electrochemical characteristics are examined using cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode shows good ascorbic acid sensing characteristics, with a linear range of 1–400 μM, a sensitivity of 546 μA mM−1 cm−2, and a limit of detection of 0.11 μM. High performance and low cost results in a promising platform to support the widespread, cheap monitoring of ascorbic acid deficiency.

Physical Modifications of Kombucha‐Derived Bacterial Nanocellulose: Toward a Functional Bionanocomposite Platform

AbstractSustainable functionalization of bacterial cellulose for cost‐effective bionanocomposites with desired properties has received growing attention in recent years. This article presents the results of work aimed at obtaining bionanocomposite materials based on bacterial cellulose, a natural and eco‐friendly material. Bacterial cellulose obtained from the Kombucha symbiotic culture of bacteria and yeast (SCOBY) fermentation process is functionalized by embedding with diatom frustules, silver nanoparticles (AgNPs), and poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). The effects of functionalization on mechanical, optical, plasmonic, electrical, chemiluminescent, and antimicrobial properties are evaluated. Morphological characteristics of the nanocomposites are studied using electron microscopy. Addition of diatom frustules introduced into the SCOBY culture media results in bionanocomposite materials with enhanced tensile strength and increased ultraviolet (UV) blockage properties. In situ functionalization of bacterial cellulose with AgNPs tunes plasmonic and chemiluminescent properties, revealing the biosensing potential of the material. Modified bacterial cellulose shows antimicrobial activity in experiments with gram‐positive and gram‐negative bacteria. Dual functionalization of bacterial cellulose with PEDOT:PSS and AgNPs results in improved electrical conductivity of the bionanocomposite. Overall, bottom‐up physical functionalization approaches and the resulting bionanocomposite materials will open up new opportunities for the low‐cost production of green materials and contribute to the development of a sustainable economy.

Ag:PSS polyelectrolyte/PTB7 bilayers as efficient hole transport layers for perovskite solar cells

By virtue of the exceptional optical and electrical features of organic-inorganic lead-halide perovskites, the power conversion efficiency (PCE) of perovskite solar cells (PeSCs) has surpassed that of commercialized single junction silicon solar cells. Although PeSCs have demonstrated exceptional efficiency, there is still room for improvement to approach the theoretical Shockley-Queisser limit. Additionally, there is a need for the development of cost-effective strategies to produce high-performance devices, enabling PeSCs to fulfill their potential as a widely adopted and sustainable energy source.Considering this, in this work, we’ve developed a polyelectrolyte (silver poly(styrene sulfonate (PSS)) (Ag:PSS) hole transport layer (HTL), and investigated it in combination with a conjugated polymer,poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b]-dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl] (PTB7) as a bilayer HTL. Ag:PSS alone performs poorly due to mismatched energy levels at the anode interface, however, when PTB7 is used in combination with Ag:PSS, effective extraction and transport of carriers towards the anode is achieved. PeSCs with optimized bilayer HTLs (Ag:PSS/PTB7) gave PCEs of up to 17.09 %, higher than that of the Ag:PSS alone (reference device 12.13 %) which can be attributed to improved interfacial energetics at the HTL/perovskite interface.

Use of Fludrocortisone for Hyperkalemia in Chronic Kidney Disease Not Yet on Dialysis.

Hyperkalemia is a frequent and potentially lethal complication of chronic kidney disease (CKD). We retrospectively examined the potassium-lowering effect of oral fludrocortisone and its adverse effects in hyperkalemic CKD patients not yet on dialysis. Thirty-three patients (23 men and 10 women, ages 69±14 years) were included. To control hyperkalemia at the outpatient clinic, twenty-one patients (Group 1) received fludrocortisone (0.05-0.1 mg/day) without changes in angiotensin II receptor blockers (ARBs) and calcium polystyrene sulfonate (CPS), while twelve patients (Group 2) were treated with fludrocortisone in addition to stopping ARBs and/or adding low-dose CPS. Fludrocortisone was administered for a median of 169 days (interquartile range, 47-445). At the first follow-up after fludrocortisone administration, serum potassium dropped from 6.14±0.32 mEq/L to 4.52±1.06 mEq/L (p<0.001) in Group 1 and from 6.37±0.35 mEq/L to 4.08±0.74 mEq/L (p<0.01) in Group 2. Ten patients in Group 1 and five patients in Group 2 measured serum potassium levels at four outpatient visits before and after fludrocortisone administration, respectively. The frequency of serum potassium ≥6.0 mEq/L decreased from 19/40 (48%) to 2/40 (5%) (p<0.001) in Group 1 and from 11/20 (55%) to 0/20 (0%) (p<0.001) in Group 2. Eleven patients experienced sodium retention-related problems after fludrocortisone administration: 7 with worsening leg edema, 2 with pleural effusions, and 2 with pulmonary edema. In pre-dialysis CKD patients, fludrocortisone at low doses effectively reduced serum potassium levels; however, sodium retention was a common adverse effect.

97‐4: Late‐News Paper: Visible Light Detection Enhancement of Indium‐Gallium‐Zinc Oxide Phototransistor with a Formation of p‐n Junction Using PEDOT:PSS Absorption Layer

In this paper, an indium‐gallium‐zinc oxide (IGZO) based phototransistor with an electrohydrodynamic (EHD) jet printed poly (3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) absorption layer has been developed for the absorption of visible light. The PEDOT:PSS absorption layerforms a p‐n junction with IGZO, enhancing the photoresponse through selective carrier transfer of photogenerated carriers. As a result, the proposed phototransistor exhibits improved optoelectronic characteristics such as photoresponsivity of 8.40 × 102 A/W, photosensitivity of 1.12 × 107, detectivity of 8.05 × 1011 Jones under the green light (532 nm) illumination of 5 mW/mm2.

Cation-Dependence in Electrochemical Dedoping of Heterogeneous Organic Mixed Ionic-Electronic Conductors

Organic electrochemical transistors (OECTs) are emerging as next-generation bioelectronic devices and neuromorphic systems. In OECTs, permeation of mobile ions from an electrolyte leads to changes in bulk conductivity of the channel. The channel materials are typically organic mixed ionic-electronic conductors (OMIECs), which exhibit high performance in both electronic and ionic transport. Among these OMIECs, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is the most widely used. However, there have been ambiguities regarding the electrochemical doping process of PEDOT:PSS. This study aims to elucidate these ambiguities by investigating the ion dependence of the electrochemical doping process.

Interaction between methyl red and cetyltrimethylammonium bromide under the influence of sodium polystyrene sulphonate in ethanol-water binary solvent systems: A spectrophotometric investigation

This research aims to comprehensively investigate and analyze the UV–visible spectroscopic behavior of the methyl red (MR)-cetyltrimethylammonium bromide (CTAB) system under the influence of sodium polystyrene sulfonate (NaPSS) in aqueous and different volume fractions (v.f.) of ethanol (EtOH)–H2O (0.1, 0.2, and 0.3) at 298.15 ± 0.2 K. In EtOH–H2O solvent systems, the triple interactions of dyes-surfactants-polyelectrolyte (DSP) complex systems are entirely novel. MR interacts with CTAB in NaPSS in the binary solvent media (0.1, 0.2, and 0.3 v.f. of EtOH–H2O) resulting in the formation of ion-pairs at very low CTAB concentrations, far below their apparent critical micelle concentration (CMC*) reducing the absorbance, and the new complexes above the CMC* due to solubilization of the MR into CTAB micelles observed by distinct spectral shifts. The CMC* values obtained from spectroscopic data increase in the order: (CMC*)water< (CMC*)0.1< (CMC*)0.2< (CMC*)0.3. This is because of the reduced polarity or dielectric constant and increased degree of water structure disruption around the hydrophobic chains of CTAB, where micelle formation occurs at somewhat higher concentrations. The Gibbs energy of micellization (ΔGmo) increases in the order: (ΔGmo=−16.89)water <(ΔGmo=−16.17)0.1<(ΔGmo=−15.62)0.2<(ΔGmo=−15.38)0.3, which further supports the inhibitory effect of increasing ethanol content towards micellization. In the post-micellar region, the decrease in hydrophobic interactions and an increase in electrostatic interactions lead to a rise in the overall binding constant value. This means that, when NaPSS is present, the stronger electrostatic interactions in the post-micellar region contribute significantly to the increased binding of CTAB micelles with MR. The tautomeric activity of MR and the solvent composition played a prime role in affecting the interaction mechanism, as evidenced by the blue and red spectral shifts.

Enhanced ophthalmic bioavailability and stability of atropine sulfate via sustained release particles using polystyrene sulfonate resin

Atropine sulfate (ATS) eye drops at low concentrations constitute a limited selection for myopia treatment, with challenges such as low ophthalmic bioavailability and inadequate stability. This study proposes a novel strategy by synthesizing ophthalmic sodium polystyrene sulfonate resin (SPSR) characterized by a spherical shape and uniform size for cationic exchange with ATS. The formulation of ATS@SPSR suspension eye drops incorporates xanthan gum and hydroxypropyl methylcellulose (HPMC) as suspending agents. In vitro studies demonstrated that ATS@SPSR suspension eye drops exhibited sustained release characteristics, and tropic acid, its degradation product, remained undetected for 30 days at 40 °C. The ATS levels in the tear fluids and aqueous humor of New Zealand rabbits indicated a significant increase in mean residence time (MRT) and area under the drug concentration–time curve (AUC0-12h) for ATS@SPSR suspension eye drops compared to conventional ATS eye drops. Moreover, safety assessment confirmed the non-irritating nature of ATS@SPSR suspension eye drops in rabbit eyes. In conclusion, the cation-responsive sustained-release ATS@SPSR suspension eye drops enhanced the bioavailability and stability of ATS, offering a promising avenue for myopia treatment.

Microwave Effect in Hydrolysis of Levoglucosan with a Solid Acid Catalyst for Pyrolysis-Based Cellulose Saccharification.

Pyrolysis-based saccharification consisting of fast pyrolysis followed by hydrolysis of the resulting anhydrosugars such as levoglucosan is a promising method for converting cellulosic biomass into glucose that can be used for producing biofuels and biochemicals. In the present study, hydrolysis of levoglucosan was evaluated in water with a polystyrene sulfonic acid resin (a solid acid catalyst) by heating under microwave irradiation or in an oil bath at 95 °C-120 °C. When the equilibrium temperature of the solution was the same, the conversion rate of levoglucosan was greater under microwave irradiation than in an oil bath. Model experiments indicate that the sulfonyl groups of the solid acid catalyst were selectively heated by microwave irradiation. The temperature of the reaction solution in the vicinity of the catalyst was locally higher than the equilibrium temperature of the solution, which enabled hydrolysis to proceed efficiently.

Characterization of Polyallylamine/Polystyrene Sulfonate Polyelectrolyte Microcapsules Formed on Solid Cores: Morphology.

Polyelectrolyte microcapsules (PMC) based on polyallylamine and polystyrene sulfonate are utilized in various fields of human activity, including medicine, textiles, and the food industry, among others. However, characteristics such as microcapsule size, shell thickness, and pore size are not sufficiently studied and systematized, even though they determine the possibility of using microcapsules in applied tasks. The aim of this review is to identify general patterns and gaps in the study of the morphology of polyelectrolyte microcapsules obtained by the alternate adsorption of polystyrene sulfonate and polyallylamine on different solid cores. First and foremost, it was found that the morphological change in polyelectrolyte microcapsules formed on different cores exhibits a significant difference in response to varying stimuli. Factors such as ionic strength, the acidity of the medium, and temperature have different effects on the size of the microcapsules, the thickness of their shells, and the number and size of their pores. At present, the morphology of the microcapsules formed on the melamine formaldehyde core has been most studied, while the morphology of microcapsules formed on other types of cores is scarcely studied. In addition, modern methods of nanoscale system analysis will allow for an objective assessment of PMC characteristics and provide a fresh perspective on the subject of research.

Imperceptible augmentation of living systems with organic bioelectronic fibres

The functional and sensory augmentation of living structures, such as human skin and plant epidermis, with electronics can be used to create platforms for health management and environmental monitoring. Ideally, such bioelectronic interfaces should not obstruct the inherent sensations and physiological changes of their hosts. The full life cycle of the interfaces should also be designed to minimize their environmental footprint. Here we report imperceptible augmentation of living systems through in situ tethering of organic bioelectronic fibres. Using an orbital spinning technique, substrate-free and open fibre networks—which are based on poly (3,4-ethylenedioxythiophene):polystyrene sulfonate—can be tethered to biological surfaces, including fingertips, chick embryos and plants. We use customizable fibre networks to create on-skin electrodes that can record electrocardiogram and electromyography signals, skin-gated organic electrochemical transistors and augmented touch and plant interfaces. We also show that the fibres can be used to couple prefabricated microelectronics and electronic textiles, and that the fibres can be repaired, upgraded and recycled.

3D printed PEDOT:PSS-based conducting and patternable eutectogel electrodes for machine learning on textiles

The proliferation of medical wearables necessitates the development of novel electrodes for cutaneous electrophysiology. In this work, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is combined with a deep eutectic solvent (DES) and polyethylene glycol diacrylate (PEGDA) to develop printable and biocompatible electrodes for long-term cutaneous electrophysiology recordings. The impact of printing parameters on the conducting properties, morphological characteristics, mechanical stability and biocompatibility of the material were investigated. The optimised eutectogel formulations were fabricated in four different patterns —flat, pyramidal, striped and wavy— to explore the influence of electrode geometry on skin conformability and mechanical contact. These electrodes were employed for impedance and forearm EMG measurements. Furthermore, arrays of twenty electrodes were embedded into a textile and used to generate body surface potential maps (BSPMs) of the forearm, where different finger movements were recorded and analysed. Finally, BSPMs for three different letters (B, I, O) in sign-language were recorded and used to train a logistic regressor classifier able to reliably identify each letter. This novel cutaneous electrode fabrication approach offers new opportunities for long-term electrophysiological recordings, online sign-language translation and brain-machine interfaces.

#1926 Persistence to first- and second- generation potassium binder treatment—an observational study based on the DEMONSTRATE database

Abstract Background and Aims Hyperkalemia (HK) is a common electrolyte abnormality mainly caused by reduced renal potassium excretion in patients with chronic kidney disease (CKD). Potassium binders, such as sodium polystyrene sulfonates (SPS) are widely used but may lead to adverse gastrointestinal (GI) symptoms, reducing their tolerability. Patiromer and sodium zirconium cyclosilicate (SZC) are newer ion exchange resins for treatment of HK which may cause fewer GI side-effects. This study aims to evaluate the persistence to first- (SPS) and second-generation potassium binder (patiromer and SZC) treatment and the related clinical characteristics. Method In this observational study based on the DEMONSTRATE database, a novel national and regional database comprising laboratory data from six regions in central Sweden (18% of the Swedish population), linked to the national health registry data, we selected all patients in Sweden having at least one pharmacy dispensation of either first (SPS) or second (patiromer or SZC) generation potassium binder between July 2005 and December 2022. By semi-automatically interpreting the prescribed dosages in combination with the amount of medical supply, duration for each dispensation was estimated and episodes of potassium binder treatments were established. For all potassium binder episodes, we described patient characteristics and persistence to treatment. Results are mainly presented by treatment episodes and by strata of (a) all, (b) first and (c) second generation potassium binders. Results Between July 2005 and December 2022, we identified 68 133 treatment episodes of potassium binders for 32 424 patients (Table 1). Of these, 31 730 individuals and 66 309 treatment episodes were attributed to first generation (throughout the study period), and 1,276 individuals and 1,824 treatment episodes to second-generation potassium binders (between 2018-2022) Mean (SD) age was slightly lower in patients initiating second compared to first generation potassium binders; 68.5 (15.6) vs 65.2 (16.6) years. Potassium binder treatment was more common in men compared to women (66.9% vs. 33.1%) with similar gender distribution between first- and second-generation potassium binders. Comorbidities were more common in patients initiating treatment with second than first generation potassium binders, notably for heart failure (40.0% vs. 29.7%) and dialysis (38.8% vs 29.2%). RAASi and MRA were more often prescribed to the second generation potassium binders vs first; 70.8% vs 62.9% for RAASi and 18.8% vs. 8.5% for MRA. Second generation potassium binders were more commonly initiated in cardiology/internal medicine units (41.7% vs. 34.8%) and dialysis (38.8% vs. 29.2%). Persistence was higher among patients treated with second generation potassium binders (Fig. 1). Conclusion Second generation potassium binders were more often prescribed to younger patients that had more co-morbidities being slightly more persistent to treatment when compared to patients on first generation potassium binders.

#1802 Treatment with potassium binders in central Sweden—an observational study based on the DEMONSTRATE database

Abstract Background and Aims Hyperkalemia (HK), defined as a plasma potassium level (&amp;gt; 5.0 mmol/L), is associated with adverse outcomes, including cardiac arrhythmias and mortality. Until recently, HK was managed mainly with sodium polystyrene sulfonate (SPS) (first generation potassium binders) but concerns regarding the safety profile warranted new alternatives. The second-generation potassium binders, patiromer and sodium zirconium cyclosilicate (SZC) were introduced in Sweden in 2018 and 2019 respectively. The aim of this observational study was to understand the current use of new potassium binders, the related potassium values triggering treatment and to describe the clinical characteristics of patients treated with first- and second-generation potassium binders (SPS and patiromer/SZC respectively) in Sweden. Method An observational study based on laboratory data from six regions in central Sweden (18% of the Swedish population), linked to national health registry data, comprising information on clinical events and pharmacy drug dispensations. All treatment episodes of potassium binders between 01 July 2005 and 31 December 2022 were selected and restricted to patients with information on potassium values. A new treatment episode was defined as a gap of at least 120 days to the prior pharmacy dispensations of potassium binders. We analyzed potassium values (up to 60 days prior to initiation of potassium binders), demographics, comorbidities and treatments. Results are mainly presented by treatment episodes and strata of; (a) all, (b) first- and (c) second-generation potassium binders. Results In total, we identified 13 441 treatment episodes of which 13 218 episodes (n = 7086 individuals), were attributed to first generation potassium binders (throughout the study period) and 223 episodes (n = 151 individuals) to second-generation potassium binders (from 2018-2022) (Table 1). Baseline characteristics are presented by treatment episodes. Baseline potassium value prior to treatment was 5.6 (0.8) mmol/L for first and 5.6 (0.7) for second generation potassium binders. Mean eGFR prior to treatment was 22.3 (16.3) ml/min/1.73 m2 for first and 18.7 (16.0) for second-generation potassium binders. Compared to first generation, second-generation potassium binders were prescribed to patients with more comorbidities (41.7% vs 32.1% for heart failure, 88.3% vs 81.7% for hypertension, and 39.5% vs 28.9% for dialysis) and more frequently from cardiology/internal medicine units (41.7% vs 30.0%). Distribution of potassium levels at baseline is shown in Fig. 1. Conclusion Compared to first- generation potassium binder, we observed fewer treatment episodes with second generation potassium binders, of which majority had a more severe comorbidity profile. There was no difference in potassium values prior to treatment between first- and second-generation potassium-binders.

Hygro‐Dynamic and Conductive Actuator That Restructures and Heals by Water

AbstractThe prospects of endowing stimuli‐responsive materials with various life‐like behaviors are promoting the development of intelligent robotic and electronic devices. However, it is challenging to incorporate stimuli‐responsive actuating and healing capabilities into one single material system. Herein, the design and assembly of humidity‐responsive thin films composed of poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and sodium carboxymethyl cellulose (NaCMC) forming a conducting polymer composite through a physically cross‐linked and hydrogen‐bonded supramolecular network are described. Owing to its enhanced dynamics of hydrogen bonding at an elevated humidity, the PEDOT:PSS/NaCMC thin film exhibits a rapid humidity‐responsive actuating performance in an environment with humidity gradient, as well as a repairing function of the structural, mechanical, electrical, and actuating properties after being damaged through a humidifying‐drying cycle. Based on a combined analytical approach, a structural model is proposed for the rearrangement of the thin film when being exposed to stepwise humidity levels at multi‐length scales. Due to the structural rearrangement powered by humidity variations, the film exhibits tunable actuating and healing performance, which makes it a promising candidate material for applications in intelligent soft robotics such as artificial muscles.

#3106 The prevalence and degree of hyperkalaemia in adult patients with chronic kidney disease, in Durban, South Africa

Abstract Background and Aims Hyperkalaemia is a known risk factor for the development of cardiac rhythm disturbances and sudden cardiac death. The presence of chronic kidney disease (CKD) is also an independent risk factor for cardiovascular complications. The prevalence of hyperkalaemia in patients with CKD has previously varied widely between studies. The prevalence of hyperkalaemia in the patients attending the renal clinic at Inkosi Albert Luthuli Central Hospital (IALCH) has not been previously determined. This study aimed to discover the prevalence of hyperkalaemia in patients attending the renal clinic at IALCH, as well as the degree of severity amongst the patients in whom hyperkalaemia was present. Demographic and other variables were also assessed for an association with hyperkalaemia. Method A retrospective review of outpatients attending the renal clinic at IALCH from 1 October 2016 until 30 September 2017. Demographic and clinical characteristics were retrieved and descriptive statistical methods and logistic regression analysis were performed. Results The study consisted of 200 patients, of whom the majority were female (n=120, 60%). The prevalence of hyperkalaemia amongst these patients was found to be 16%. In those with stage 3 CKD, the prevalence of hyperkalaemia was 7.69%. In those with stage 4 CKD, the prevalence of hyperkalaemia was 20.5% and in those with stage 5 CKD the prevalence was 17.3%. There were no statistically significant associations between hyperkalaemia and demographic variables, nor with dietician intervention. There was a significant association with the use of sodium polystyrene sulfonate. Conclusion CKD is a growing burden in the developing world. With CKD comes metabolic and other derangements, including electrolyte abnormalities as well as increased cardiovascular risk. Hyperkalaemia is associated with worsening CKD. In addition, hyperkalaemia puts patients at risk of cardiac dysrhythmias and sudden cardiac death. Pharmacological measures to manage CVD risk should be weighed up against the risk of hyperkalaemia related complications. Potassium lowering agents should be considered to allow for optimal CVD management in the setting of hyperkalaemia in CKD.