Electrochemical sensors, with high accuracy, good selectivity, and linear response, have been widely used for environmental protection, health monitoring, and disease treatment. However, to date, these sensors still have limit sensitivity or otherwise require the use of high-cost materials such as noble metals and enzymes. Here, we report a novel electrochemical sensor using a topological insulator, Bi2Te3. Through liquid-phase exfoliation, we prepared nano- and microflakes of Bi2Te3 and measured their performance in hydrogen peroxide sensing via electrocatalytic reduction processes. Our devices exhibit a sensitivity of ∼4900 μA mM-1 cm-2 and a detection limit of ∼10-8 molar, both of which are superior to typical noble metal-based electrochemical sensors. Through electrochemical analysis and microkinetic simulations, we extracted the kinetic parameters and gained insights into the reaction mechanism. We attribute the ultrahigh sensitivity to the facile electron transfer at the Bi2Te3-aqueous solution interface.Bacteria capable of complete ammonia oxidation (comammox) are widespread and contribute to nitrification in wastewater treatment facilities. However, their roles in partial nitrification-anaerobic ammonium oxidation (anammox) systems remain unclear. In this study, a bench-scale bioreactor with continuous stirring was operated for more than 1000 days with limited oxygen supply to achieve efficient nitrogen removal (70.1 ± 2.7%) at a low ammonium loading of 35.2 mg-N/L/day. High-throughput amplicon sequencing analysis of the comammox ammonia monooxygenase subunit A (amoA) gene revealed seven sequence types from two clusters in clade A of comammox Nitrospira. Quantitative polymerase chain reaction analyses suggested that the comammox species dominated the ammonia-oxidizing community, with an abundance as high as 89.2 ± 7.9% in total prokaryotic amoA copies. Multiple linear regression further revealed the substantial contribution of the comammox Nitrospira to ammonia oxidation in the bioreactor. The investigation with bioreactor and batch experiments consistently showed that activities of comammox Nitrospira were inhibited by free ammonia far more severely than other ammonia-oxidizing microbes. Overall, this study provided new insight into the ecology of comammox Nitrospira under hypoxic conditions and suggested comammox-associated partial nitrification-anammox as a potential method for treating low-strength ammonium-containing wastewater.Transmembrane proteins within biological membranes exhibit varieties of important functions that are vital for many cellular activities, and the development of their synthetic mimetics allows for deep understanding in related biological events. Inspired by the structures and functions of natural ion channels that can respond to multiple stimuli in an anisotropic manner, we developed multiblock amphiphile VF in this study. When VF was incorporated into the lipid bilayer membranes, VF formed a supramolecular ion channel whose ion transport property was controllable by the polarity and amplitude of the applied voltage. Cepharanthine mouse Microscopic emission spectroscopy revealed that VF changed its molecular conformation in response to the applied voltage. Furthermore, the ion transport property of VF could be reversibly switched by the addition of (R)-propranolol, an aromatic amine known as an antiarrhythmic agent, followed by the addition of β-cyclodextrin for its removal. The highly regulated orientation of VF allowed for an anisotropic dual-stimuli-responsiveness for the first time as a synthetic ion channel.A photocatalytic metal-free, visible-light-driven, highly atom-economic, direct multiple α-C(sp3)-H alkylation of phosphoramides and thiophosphoramides is demonstrated under environmentally benign conditions. Economically viable and commercially available Eosin-Y is used as an HAT photocatalyst for mono-α-C(sp3)-H alkylation of phosphoramide derivatives. Remarkably, di- and tri-C(sp3)-H alkylation of phosphoramides and thiophosphoramides using an acridinium photocatalyst is reported with good yield and selectivity. Mechanistic studies reveal that monoalkylation of phosphoramides by Eosin-Y follows the HAT mechanism, whereas di- and tri-C(sp3)-H alkylation by the acridinium photocatalyst follows the SET mechanism.Effective nonprecious metal catalysts are urgently needed for hydrogen evolution reaction (HER). The hybridization of N-doped graphene and a cost-effective metal is expected to be a promising approach for enhanced HER performance but faces bottlenecks in controllable fabrication. Herein, a silica medium-assisted method is developed for the high-efficient synthesis of single-layer N-doped graphene encapsulating nickel nanoparticles (Ni@SNG), where silica nanosheets molecule sieves tactfully assist the self-limiting growth of single-layer graphene over Ni nanoparticles by depressing the diffusion of gaseous carbon radical reactants. The Ni@SNG sample synthesized at 800 °C shows excellent activity for HER in alkaline medium with a low overpotential of 99.8 mV at 10 mA cm-2, which is close to that of the state-of-the-art Pt/C catalyst. Significantly, the Ni@SNG catalyst is also developed as a binder-free electrode in magnetic field, exhibiting much improved performance than the common Nafion binder-based electrode. Therefore, the magnetism adsorption technique will be a greatly promising approach to overcome the high electron resistance and poor adhesive stability of polymer binder-based electrodes in practical applications.The hydration thermodynamics of amyloid-β (Aβ) and its pathogenic familial Alzheimer’s disease (FAD) mutants such as A2V, Taiwan (D7H), Tottori (D7N), and English (H6R) and the protective A2T mutant is investigated by a combination of all-atom, explicit water molecular dynamics (MD) simulations and the three-dimensional reference interaction site model (3D-RISM) theory. The change in the hydration free energy on mutation is decomposed into the energetic and entropic components, which comprise electrostatic and nonelectrostatic contributions. An increase in the hydration free energy is observed for A2V, D7H, D7N, and H6R mutations that increase the aggregation propensity of Aβ and lead to an early onset of Alzheimer’s disease, while a reverse trend is noted for the protective A2T mutation. An antiphase correlation is found between the change in the hydration energy and the internal energy of Aβ upon mutation. A residue-wise decomposition analysis shows that the change in the hydration free energy of Aβ on mutation is primarily due to the hydration/dehydration of the side-chain atoms of the negatively charged residues.