Fungal biomineralization of toxic metals accelerates organic pollutant removal.

Fungal biomineralization plays an important role in the biogeochemical cycling of metals in the environment and has been extensively explored for bioremediation and element biorecovery. However, the cellular and metabolic responses of fungi in the presence of toxic metals during biomineralization and their impact on organic matter transformations are unclear. This is an important question because co-contamination by toxic metals and organic pollutants is a common phenomenon in the natural environment. In this research, the biomineralization process and oxidative stress response of the geoactive soil fungus Aspergillus niger were investigated in the presence of toxic metals (Co, Cu, Mn, and Fe) and the azo dye orange II (AO II). We have found that the co-existence of toxic metals and AO II not only enhanced the fungal biomineralization of toxic metals but also accelerated the removal of AO II. We hypothesize that the fungus and in situ mycogenic biominerals (toxic metal oxalates) constituted a quasi-bioreactor, where the biominerals removed organic pollutants by catalyzing reactive oxygen species (ROS) generation resulting from oxidative stress. We have therefore demonstrated that a fungal/biomineral system can successfully achieve the goal of toxic metal immobilization and organic pollutant decomposition. Such findings inform the potential development of fungal-biomineral hybrid systems for mixed pollutant bioremediation as well as provide further understanding of fungal organic-inorganic pollutant transformations in the environment and their importance in biogeochemical cycles.

Correlating Young's Modulus with High Thermal Conductivity in Organic Conjugated Small Molecules.

Attaining elevated thermal conductivity in organic materials stands as a coveted objective, particularly within electronic packaging, thermal interface materials, and organic matrix heat exchangers. These applications have reignited interest in researching thermally conductive organic materials. The understanding of thermal transport mechanisms in these organic materials is currently constrained. This study concentrates on N, N'-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8), an organic conjugated crystal. A correlation between elevated thermal conductivity and augmented Young's modulus is substantiated through meticulous experimentation. Achievement via employing the physical vapor transport method, capitalizing on the robust C═C covalent linkages running through the organic matrix chain, bolstered by π-π stacking and noncovalent affiliations that intertwine the chains. The coexistence of these dynamic interactions, alongside the perpendicular alignment of PTCDI-C8 molecules, is confirmed through structural analysis. PTCDI-C8 thin film exhibits an out-of-plane thermal conductivity of 3.1 ± 0.1 W m-1 K-1, as determined by time-domain thermoreflectance. This outpaces conventional organic materials by an order of magnitude. Nanoindentation tests and molecular dynamics simulations elucidate how molecular orientation and intermolecular forces within PTCDI-C8 molecules drive the film's high Young's modulus, contributing to its elevated thermal conductivity. This study's progress offers theoretical guidance for designing high thermal conductivity organic materials, expanding their applications and performance potential.

Organic Conjugated Small Molecules with High Thermal Conductivity as an Effective Coupling Layer for Heat Transfer.

As the features of electronics are miniaturized, the need for interfacial thermal coupling layers to enhance their thermal transfer efficiency and improve device performance becomes critical. Organic conjugated small molecules possess a unique combination of periodic crystal structures and conjugated units with π electrons, resulting in notable thermal conductivities and molecular structure orientation that facilitates directed heat transfer. Nevertheless, there is a noticeable gap in literatures regarding the thermal properties of organic conjugated small molecules and their potential applications in nanoscale thermal management. Herein, we report the fabrication of high-quality thin films of organic conjugated small molecules. The result reveals that the 2D organic conjugated small molecule thin films exhibit a high cross-plane thermal conductivity of 3.2 W/m K. The increased thermal conductivity is attributed to the well-organized lattice structure and existence of π-electrons induced by conjugated systems. The studied conjugated small molecules engage in π-π stacking interactions with carbon materials and efficiently exchange energy with electrons in metals, promoting rapid interfacial heat transfer. These molecules act as coupling layers, significantly enhancing thermal transfer efficiency between graphite-based thermal pads and copper heat sinks. This pioneering research represents the inaugural investigation of the thermal performance of conjugated organic small molecules. These findings highlight the potential of conjugated small molecules as thermal coupling layers, offering tunable combinations of desirable properties.

Creating Biomimetic Central-Radial Skeletons with Efficient Mass Adsorption and Transport.

Porous skeletons play a crucial role in various applications. Their fundamental significance stems from their remarkable surface area and capacity to enhance mass adsorption and transport. Freeze-casting is a commonly utilized methodology for the production of porous skeletons featuring vertically aligned channels. Nevertheless, the resultant single-oriented skeleton displays anisotropic mass transfer characteristics and suboptimal mechanical properties. Our investigation was motivated by the intricate microstructures observed in botanical organisms, leading us to devise an advanced freeze-casting methodology. A novel central-radial skeleton with significantly enhanced capabilities has been successfully engineered. The central-radial architecture demonstrates superior refinement and uniformity in its pore structure, featuring an axial mass transfer axis and meticulously arranged radial channels. This microstructure endows the porous skeleton with a higher compression resilience, superior adsorption rate, and structural maintenance capacity. Through a rigorous examination of the thermal conductivity of skeleton-filled composites coupled with comprehensive COMSOL simulations, the exceptional characteristics of this unique structural arrangement have been definitively ascertained. Furthermore, the efficacy of implementing this skeleton in chip cooling and photothermal conversion has been convincingly substantiated. Our pioneering method of microstructure preparation, employing freeze-casting, holds immense potential in expanding its applicability and inspiring innovative concepts for the advancement of novel structures.

Median effective dose of esketamine for intranasal premedication in children with congenital heart disease.

BACKGROUND: Esketamine is commonly used as a premedication for its sedation effect. However, the proper dosage for intranasal use in children with congenital heart disease (CHD) has not been determined. This study aimed to estimate the median effective dose (ED50) of esketamine for intranasal premedication in children with CHD. METHODS: Thirty-four children with CHD who needed premedication in March 2021 were enrolled. Intranasal esketamine was initiated at a dose of 1 mg/kg. Based on the outcome of sedation in the previous patient, the dose for the subsequent patient was either increased or reduced by 0.1 mg/kg, which was adjusted between each child. Successful sedation was defined as a Ramsay Sedation Scale score ≥ 3 and Parental Separation Anxiety Scale score ≤ 2. The required ED50 of esketamine was calculated using the modified sequential method. Non-invasive blood pressure, heart rate, saturation of peripheral oxygen, sedation onset time, and adverse reactions were recorded at 5 min intervals after drug administration. RESULTS: The 34 children enrolled had a mean age of 22.5 ± 16.4 (4-54) months and a mean weight of 11.2 ± 3.6 (5.5-20.5) kg; American Society of Anesthesiologists classification I-III. The ED50 of intranasal S(+)-ketamine (esketamine) required for preoperative sedation in pediatric patients with CHD was 0.7 (95% confidence interval: 0.54-0.86) mg/kg, and the mean sedation onset time was 16.39 ± 7.24 min. No serious adverse events, such as respiratory distress, nausea, and vomiting were observed. CONCLUSIONS: The ED50 of intranasal esketamine was 0.7 mg/kg, which was safe and effective for preoperative sedation in pediatric patients with CHD. TRIAL REGISTRATION: The trial was registered in the Chinese Clinical Trial Registry Network (ChiCTR2100044551) on 24/03/2021.

A confinement strategy to prepare N-doped reduced graphene oxide foams with desired monolithic structures for supercapacitors.

It is a challenge to achieve pure graphene foams with a desired monolithic structure in order to take advantage of the excellent properties of graphene-based macroscopic assemblies. Here, we introduced a confinement fabrication strategy to prepare nitrogen doped reduced graphene oxide foams (NrGFs) through a one-step hydrothermal process. The melamine foam (MF) skeleton was removed during the hydrothermal reaction, and the NrGF retained its desired monolithic structure by the confinement of solution ionic strength. Due to the "roof-tile-like" microscopic morphology with high N-doping (9.88 at%), the free-standing graphene foam electrode exhibited excellent capacitive performance. The resulting NrGF-based symmetric supercapacitor displayed a remarkably enhanced specific capacitance of 260 F g-1 at 0.1 A g-1 and 173 F g-1 at 20 A g-1 in an aqueous electrolyte. Moreover, the facility of fabrication makes it a promising material in many contexts for large scale production, such as energy storage, environmental remediation and strain sensors. Furthermore, this synthesis strategy can be expanded to prepare other pure macroporous foams or composites by using different building blocks (such as CNTs and MXene).

Fungal Biomineralization of Manganese as a Novel Source of Electrochemical Materials.

Electrical energy storage systems such as rechargeable lithium-ion batteries (LiBs) and supercapacitors have shown great promise as sustainable energy storage systems [1-4]. However, LiBs have high specific energy density (energy stored per unit mass) and act as slow, steady suppliers for large energy demands. In contrast, supercapacitors possess high specific power (energy transferred per unit mass per unit time) and can charge and discharge quickly for low energy demands. In LiBs, graphite is the most common anode material, although high electrolyte sensitivity and low charge capacity can limit performance. Efforts have been made to improve LiB or supercapacitor performance using alternative electrode materials such as carbon nanotubes and manganese oxides (MnxOy) [3, 5-14]. Microorganisms play significant roles in metal and mineral biotransformations [15-22]. Fungi possess various biomineralization properties, as well as a filamentous mycelium, which may provide mechanical support for mineral deposition. Although some research has been carried out on the application of biological materials as carbon precursors [8, 9, 23], biomineralizing fungal systems have not been investigated. In this research, novel electrochemical materials have been synthesized using a fungal Mn biomineralization process based on urease-mediated Mn carbonate bioprecipitation [24]. The carbonized fungal biomass-mineral composite (MycMnOx/C) showed a high specific capacitance (>350 F g(-1)) in a supercapacitor and excellent cycling stability (>90% capacity was retained after 200 cycles) in LiBs. This is the first demonstration of the synthesis of electrode materials using a fungal biomineralization process, thus providing a novel strategy for the preparation of sustainable electrochemical materials.