Cell Reports Physical Science最新文献

The chemical state of nickel anodes during the oxygen evolution reaction can impact their electrocatalytic performance. Here, X-ray photoelectron and absorption spectroscopies reveal the chemical state of nickel nanoparticles under oxygen evolution reaction conditions in a mildly alkaline carbonate-bicarbonate buffer solution. Ni²⁺ and Ni³⁺ species are observed at the reaction onset potential with a 7:4 ratio, with no remaining metallic nickel. These species include NiO, which increasingly converts to other Ni²⁺ and Ni³⁺ species once the potential is increased above the onset potential. Conversely, when a 20-nm-thick nickel film is used instead of nickel nanoparticles, a significant amount of metallic nickel remains in the inner layers. Nickel nanoparticles also undergo significant morphological and structural changes during the reaction, as evidenced by ex situ transmission electron microscopy. Amorphization of the nanoparticles is attributed to significant H₂O incorporation, with the oxygen intensity increasing both in operando and ex situ measurements.

Intensity-based fluorescence imaging suffers from spectral overlap and optical background interference. As an alternative, fluorescence lifetime measurements on the nanosecond level are also largely constrained. Herein, we propose phase-sensitive detection of photoswitchable probes containing naphthopyran and fluorescent donors. The method features reaction kinetics in the millisecond-to-second regime, allowing frequency domain detection with cost-effective equipment. A phase shift (Δϕ) in the fluorescence of the probes is extracted by fast Fourier transform, establishing a dependence on the molar ratio of donor to acceptor. Thus, Δϕ is proposed as a self-referencing quantity for selective highlighting of fluorescent probes and a dynamic signal readout in chemical sensing. Phase-sensitive detection of protamine, a polycationic protein often used as a neutralizer of the anticoagulant heparin during surgery, is successfully realized based on the platform.

Battery operating data from real-life scenarios are riddled with randomness, complexity, and multi-cell grouping, posing significant challenges for applying lifetime prognostic approaches developed from laboratory scenarios. To address this, we have conducted extensive experimental investigations into battery degradation across laboratory and real-life scenarios spanning a 4 year period, involving a total of approximately 546,000 charge-discharge cycles across hundreds of cells and packs. In addition to our experimental investigations, we develop a lifetime prognosis approach by creatively incorporating the concept of cumulative utilization lifetime. Our approach highlights the significant potential of transferring knowledge gained from standardized laboratory scenarios to diverse real-world conditions. It consistently improves performance from early prediction to real-time prediction, achieving a remarkable error margin of around 5% and millisecond-level computational efficiency on a portable laptop with no dedicated graphics. Furthermore, our experimental investigations underscore the beneficial effects of seasonal low temperatures on prolonging battery lifetime.

Cholesteric liquid crystals (CLCs) exhibit optical properties that are highly responsive to temperature or electric fields. Here, we report an approach to aiding in photosensitive epilepsy treatment by developing a thermal-controlled CLC wavelength filter lens. This lens demonstrates exceptional optical tunability, enabling it to dynamically change its stopband in response to temperature changes. At room temperature, the stopband of the CLC lens is outside the visible spectrum, rendering the lens functionally similar to normal glass. As the temperature rises to 36.5°C, the lens efficiently blocks light within the 660- to 720-nm wavelength range, which is the known trigger wavelength for photosensitive epilepsy. CLC materials with opposite handedness are used to achieve over 98% light cutoff at the stopband. We propose a control system for dynamically controlling the temperature in real time. The tunable lenses offer a solution for mitigating the effects of specific light stimuli on affected individuals.

Solution-based synthesis of complex molecules with high efficiency leverages supramolecular control over covalent bond formation. Herein, we present the mechanosynthesis of chiral mono-biotinylated hemicucurbit[8]urils (mixHC[8]s) via the condensation of D-biotin, (R,R)- or (S,S)-cyclohexa-1,2-diylurea, and paraformaldehyde. The selectivity of self-assembly is enhanced through mechanochemistry and by fostering non-covalent interactions, achieved by eliminating solvents and conducting the reaction in the solid state. Rigorous analysis of intermediates reveals key processes and chemical parameters influencing dynamic covalent chemistry. The library of ca. 50,000 theoretically predicted intermediates and products leads to covalent self-assembly of chiral hemicucurbiturils. Mechanochemically prepared diastereomeric (−)- and (+)-mixHC[8]s are suitable for anion binding and derivatization. Immobilization of the macrocycles on aminated silica produces a functional material capable of selective capture of anions, as demonstrated by efficient perchlorate removal from a spiked mineral matrix.

Aneurysm is a common disease that poses a threat to human health. Currently, treating aneurysms mainly relies on embolization using metallic microcoils. However, it is extremely difficult to insert metallic microcoils into the aneurysm inside tortuous vessels. Besides, adapting fixed metallic microcoils to different aneurysms is also a major problem. In this paper, we propose a shape-programmable robot based on a magnetic and radio frequency (RF) dual-responsive shape memory polymer (SMP). The SMP robot can move automatically to the target under a programmable magnetic field. Meanwhile, it can be heated up and will transform from a small-sized ball shape to the aneurysm shape using RF. In addition, the dual-responsive SMP has excellent mechanical properties; its tensile modulus is 50 times higher than that of traditional hydrogels, reducing the possibility of fracture during embolization. In the future, this SMP robot could be potentially suitable for clinical translation.

In the Eigen-Weller framework, acid-base reactions are described as those consisting of serial steps. The steps include the encounter of acid and base compounds, short-range proton transfer within the encounter complexes, and separation of the resulting Eigen complexes (ECs) equivalent to long-range proton diffusion. Although the initial proton transfer step in the encounter complexes has been extensively explored, the final step requisite to terminating the acid-base reactions has been overlooked. Using time-resolved fluorescence spectroscopy and chemical kinetics analysis, we track the excited-state proton transfer of a cationic acid to an aprotic base in binary solvent mixtures, where the lifetimes of ECs are prolonged. Identifying the ECs spectrally and kinetically, we investigate the molecularity in the consecutive steps of the hydrogen-bond formation between the acid and base and the dissociation of the EC to unveil the cooperative nature of the aprotic base molecules in the model reaction.

Ultrathin heat pipes (UHPs) have attracted tremendous attention in recent years. However, fabricating UHPs with high heat-transfer efficiency and low thermal expansion remains a challenge. Here, we report a design of an inverse opal complex wick for UHPs. The design enables the wick to have abundant random micropores for the transportation of vapor and ordered nanopores for the return of condensate. With the assistance of a Cu/MoCu/Cu shell, the UHP with a thickness of 0.985 mm can maintain a low coefficient of thermal expansion (7.3E−6 /K) and allow a gallium nitride (GaN) chip to work at a heat flux of 208 W/cm². When the liquid filling ratio reaches 54%, a lower thermal resistance of 0.8 K/W and a higher thermal conductivity of 11,076 W/(m⋅K) are realized. This study demonstrates the successful fabrication of high-performance UHPs, promoting the development of inverse opal wicks from materials to devices.