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Polyelectrolyte complex coacervation underpins many critical biological processes, yet how different initial mixing protocols determine its liquid-liquid phase separation (LLPS) dynamics remains unclear. Using molecular dynamics simulations, we show that when polycations and polyanions are initially randomly mixed, coacervate domain growth exhibits transient t 1/2 scaling, driven by polymer network formation. This phase is followed by either t 1 scaling due to hydrodynamic pumping or t 1/3 scaling from droplet coarsening, depending on the initial mixing degree. Conversely, starting with spatially separated domains of polycations and polyanions-mimicking LLPS in certain marine organisms-leads to rapid coacervate formation, with early-stage growth following distinct t 2/3 scaling due to strong electrostatic attraction, followed by continued growth via polymer accumulation. Both protocols yield significantly faster dynamics than systems initialized with preformed polyion pairs, which exhibit classical t 1/3 scaling characteristic of droplet coarsening. These findings highlight the profound impact of initial conditions on LLPS dynamics in polyelectrolyte systems. Liquid-liquid phase separation is a process of interest, but the dynamics are still not fully understood. Here, the authors use molecular dynamics to consider the role of mixing protocol in polyelectrolyte complex coacervation.

Highly-charged intrinsically disordered proteins (IDPs) underpin biomolecular condensate formation through liquid–liquid phase separation, yet the influence of charge sequences on the dynamics within the condensate phase remains poorly understood. Using extensive molecular dynamics simulations with explicit hydrodynamics and electrostatics, we study the dynamics in IDP condensates across different length and time scales, by systematically varying the charge sequences of the constituent IDPs. Contrary to the expectation that long-range interactions are heavily screened in dense semidilute polymer solutions, we find hydrodynamics and electrostatics significantly influence the dynamics in IDP condensates and their effects are strongly coupled to the charge sequence of the constituent IDPs. For condensates of low to intermediate- κ IDPs, where κ is a measure of the charge blockiness of the charge sequence, we find hydrodynamics dominates the dynamics up to the length scale of the chain and beyond. On the sub-chain level, segmental relaxation is highly coupled to intra-chain electrostatic correlations due to local charge patterns, where sections with more charge-balanced blocks have faster relaxation. Furthermore, the viscosity in IDP condensates is significantly length-scale-dependent, with condensates of high- κ IDPs exhibiting large difference between microscopic and macroscopic viscosity. Such length-scale-dependent viscosity may be the key to understanding the experimentally observed extremely fast molecule-level dynamics in biocondensates of highly-charged IDPs. Our findings highlight the intricate relationship between charge sequences, hydrodynamics, and electrostatics in shaping the dynamics in IDP condensates at different length and time scales. Highly-charged intrinsically disordered proteins (IDPs) underpin biomolecular condensate formation, however, the influence of charge sequences on the dynamics within the condensate phase remains underexplored. Here, the authors use molecular dynamics simulations with explicit hydrodynamics and electrostatics to study the dynamics in IDP condensates across different length and time scales by varying the charge sequences of the constituent IDPs, showing that hydrodynamic and electrostatic effects are strongly coupled to the IDP charge sequence, in contrast with the expectation of long-range interactions being heavily screened.

To study the effect of reprocessing on the microstructure and corrosion resistance of Zr-Sn-Nb alloy, the original plates of Zr-Sn-Nb alloy were hot-rolled, cold-rolled and recrystallized to obtain the reprocessed plates. The microstructure of both plates was observed with a scanning electron microscope (SEM), a transmission electron microscope (TEM) and electron backscattering diffraction (EBSD). The original plates and reprocessed plates were put into a static autoclave for 300 days in 360 °C/18.6 MPa water. The relationship between the microstructure and corrosion resistance of the Zr-Sn-Nb alloy was discussed. The coarse deformation grains with twins and fine recrystallized grains were obtained, and grain sizes became smaller. The Ostwald ripening of second phase particles (SPPs) happened, and the average size of SPPs increased. Some SPPs changed from an HCP structure to an FCC structure. Reprocessing made the transition advance, which is related to the accelerated evolution of cracks in the oxide film and the increase in metal-oxide film interface roughness. The deterioration of corrosion resistance is closely related to the change of grain size, SPP size and SPP structure.

In pressurized water reactors, LiOH may be concentrated in some areas, leading to the accelerated corrosion of fuel claddings. Injecting boric acid into primary coolants can mitigate the accelerated corrosion effect of LiOH on Zircaloys, but the effects of boron content on the corrosion behavior of the Zr-Sn-Nb alloy are still unknown. This work focused on the corrosion and hydrogen absorption behavior at 360 °C/18.6 MPa in 100 mg/kg LiOH solutions with 0 mg/kg, 50 mg/kg, and 200 mg/kg boron contents for up to 510 days, aiming to study the effect of boron content on corrosion resistance in LiOH solutions. Corrosion kinetics, microstructures of oxide films, hydrogen absorption concentrations and hydride morphology were obtained after the test. The results show that injecting boron in LiOH solutions can significantly reduce the corrosion weight gain, hydrogen concentration, and hydrogen length of Zr-Sn-Nb alloys, that is, improving corrosion resistance effectively. During the oxidation of the Zr-Sn-Nb alloy, B3+ and Li+ incorporate in oxide films. The incorporation of Li+ may lead to the generation of oxygen vacancies, which can carry oxygen from the solutions to O/M interface, accelerating corrosion. The incorporation of B3+ in oxide films will slow down the oxidation of Zr-Sn-Nb alloys by reducing the oxygen vacancies caused by Li+ aggregation.

Differential scanning calorimetry (DSC) was used to study non-isothermal kinetics of α→β transformation of Zr-0.5wt%Sn-0.15wt%Nb-0.5wt%Fe-0.25wt%V alloy. The DSC curves were measured from room temperature to 1030 °C at the heating rate of 15, 20, 30, 50°C /min respectively. The Flynn-Wall-Ozawa (FWO) method was used to get the activation energy (E) of α→β transformation at different conversion ratios. Then the values of activation energy obtained were modified by Ozawa iterative equation. The kinetic mechanism functions of α→β transformation were investigated by Criado-Ortega methods. The results show that the activation energy is related to conversion ratios. It means α→β transformation is not a simple one-step reaction but a complex multi-step reaction. The most probable kinetic mechanism functions are different in different temperature ranges, which are -ln(1-x) for ≤830 °C, [-ln(1-x)]1/2 for 834~848 °C, [-ln(1-x)]2/5for 850~856 °C and [-ln(1-x)]1/3 for 858~868 °C respectively.

The corrosion resistance of SZA-6 zirconium alloy(Zr-0.5Sn-0.5Nb-0.3Fe-0.015Si) cladding tubes finally annealed at 480°C, 510°C and 560°C were studied by static autoclave in 360°C/18.6 MPa pure water and 360°C/18.6 MPa/0.01 mol/L LiOH aqueous solution. The microstructure of the samples before and after corrosion were analyzed by EBSD, TEM and SEM. The results showed that the corrosion weight gains of the three SZA-6 alloy samples were lower than that of Zr-4 alloy after 500 days corrosion in both hydrochemical mediums. After long-term corrosion, the corrosion weight gains of SZA-6 alloy in pure water and LiOH aqueous solution increased obviously with the final annealing temperature, while the corrosion weight gain of unstressed Zr-4 alloy was higher than that of recrystallized under the same condition. With the increase of the final annealing temperature, the high-angle grain boundaries in the alloy larger than 15° became more and recrystallization degree also increased. The Second Phase Precipitates (SPPs) were fine, uniform, and dispersively distributed with an average diameter of about 120 nm. Although the size and distribution of the SPPs were similar, the Nb/Fe ratio in the SPPs increased. The long-term corrosion weight gain of zirconium alloy was related to the number of parallel cracks in the oxide film and the uneven growth degree of the oxide film on the interface of the oxide film/matrix. The corrosion resistance of the alloy in two hydrochemical mediums was related to the degree of recrystallization and the content of Nb in the SPPs. Increasing the final annealing temperature would promote the formation of fine and uniform recrystallized grains, which was benefit to the corrosion resistance, but at the same time it would reduce the content of solid solution Nb in the αZr matrix, which in turn would be detrimental to the corrosion resistance.

The functionalities and applications of complex coacervates -- liquid condensates resulting from liquid-liquid phase separation of charged polymers -- are significantly influenced by the dispersion and aggregation states of guest macromolecules. Intriguingly, guest macromolecules exhibit a strong tendency to aggregate within coacervates even in the absence of apparent chemical incompatibility, indicating a universal aggregation mechanism at play in these environments. Using extensive MD simulations, we identify electrostatic depletion -- a strong force arising from electrostatic correlations within the host polyelectrolyte network that drives guest aggregations. Due to electrostatic depletion, neutral polymers, low-charge-density polyelectrolytes, and intrinsically disordered proteins (IDPs) exhibit effective attractions in coacervates, in stark contrast to their behavior in dilute solutions. Unlike traditional depletion effect that requires mismatched length scale and morphology, electrostatic depletion is relevant in fluid systems where solute and solvent are both polymers with comparable size. Our discovery bridges a critical knowledge gap in the molecular physics of densely charged, crowded liquids and holds significant implications for the design of synthetic protocells and advanced drug delivery systems.

Poor solubility and bioavailability have limited the application of fucoxanthin in drug and functional food processing. In order to encapsulate fucoxanthin in delivery systems, in this study, cellulose was isolated from industrial brown algae residues and high-pressure homogenized into cellulose nanofibrils (CNFs). Then, fucoxanthin was encapsulated into the Pickering emulsion stabilized by the CNFs. The effect of high-pressure homogenization on the characteristics of cellulose and the stability of fucoxanthin emulsion was evaluated. The results indicated that CNFs prepared at 105 MPa had a diameter of 87 nm and exhibited high zeta potential and thermal stability. Encapsulation efficiency peaked at 70.8% with 1.0 mg/mL fucoxanthin, and after three freeze–thaw cycles the encapsulation efficiency was higher than 60%. The DPPH scavenging activity after 12 days’ storage at 4 °C was still 42%. Furthermore, the Pickering emulsion with 1.0 mg/mL fucoxanthin showed high stability and antioxidant activity under different pH values, salinity, temperature, and UV light exposure duration. The CNFs effectively protected fucoxanthin from degradation, offering a novel delivery system for marine bioactive compounds. To the best of our knowledge, this is the first study on the fucoxanthin delivery system of Pickering emulsion stabilized by the CNFs. Such emulsion might benefit the encapsulation and release of bioactive components in marine drugs.

Chimeric antigen receptor (CAR) T therapy represents a form of immune cellular therapy with clinical efficacy and a specific target. A typical chimeric antigen receptor (CAR) construct consists of an antigen binding domain, a transmembrane domain, and a cytoplasmic domain. Nanobodies have been widely applied as the antigen binding domain of CAR-T due to their small size, optimal stability, high affinity, and manufacturing feasibility. The nanobody-based CAR structure has shown a proven function in more than ten different tumor-specific targets. After being transduced in Jurkat cells, natural killer cells, or primary T cells, the resulting nanobody-based CAR-T or CAR-NK cells demonstrate anti-tumor effects both in vitro and in vivo. Interestingly, anti-BCMA CAR-T modulated by a single nanobody or bi-valent nanobody displays comparable clinical effects with that of single-chain variable fragment (scFv)-modulated CAR-T. The application of nanobodies in CAR-T therapy has been well demonstrated from bench to bedside and displays great potential in forming advanced CAR-T for more challenging tasks.

Objective To assess the prevalence, associated factors and cardiocerebral vascular prognosis of anaemia in patients undergoing haemodialysis. Methods This multicentre, retrospective, observational cohort study included patients on maintenance haemodialysis in South Guangdong, China. Anaemia in haemodialysis was defined as haemoglobin (Hb) <90 g/l. A proportion of patients were enrolled in a follow-up of the cardiocerebral vascular prognosis. Results A total of 1161 patients were enrolled and 938 were followed-up for cardiocerebral vascular events. Of 1161 patients, 250 (21.5%) had anaemia and 524 (45.1%) had an Hb level of 100–120 g/l. Adjusted multivariate logistic regression analysis demonstrated that frequency of dialysis ≤ twice weekly, hypoalbuminaemia and use of unfractionated heparin were independent factors associated with anaemia. Kaplan–Meier survival curve analysis for no myocardial infarction was 100%, 100%, 100% and 100% after 3, 6, 9 and 12 months, respectively, in patients with Hb < 90 g/l; compared with 97%, 95%, 93% and 93%, respectively, in patients with Hb ≥ 130 g/l. Adjusted Cox proportional hazards regression demonstrated that Hb ≥ 130 g/l was an independent risk factor for myocardial infarction. Conclusion Anaemia is highly prevalent among patients undergoing haemodialysis in South Guangdong and requires careful management.