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The triboelectric nanogenerator (TENG) has been considered as an effective way to convert various mechanical energies into electrical energy. However, the energy output needs continuous improvement for potential applications. In this study, triboelectric layers composed of polyimide (PI) matrix and carbon nanotube@barium titanate (CNT@BTO) nanoparticles were developed to achieve the performance enhancement through the synergistic coupling of piezoelectric and triboelectric effects as well as the microcapacitor function. To achieve the purpose, CNT@BTO nanoparticles were synthesized by the chemical vapor deposition method and then incorporated into a flexible PI triboelectric layer prepared using electrospinning technology and thermal imidization. The results showed that when the BTO content was 26 wt % and the CNT content was 2 wt %, the open-circuit voltage and short-circuit current of a TENG based on a PI/CNT@BTO nanofiber membrane reached 305 V and 104 μA, which were 3 times higher than those of a pure PI-based TENG. The TENG demonstrated sufficient power to drive small electronic devices, such as calculators, and to light up 124 commercial green LED and 18 blue COB light sources. Additionally, the TENG was integrated into a real-time temperature-sensing alarm system, showcasing its potential application in safety-related fields. The study demonstrated the feasible methods for TENGs' performance enhancement and provided potential application fields of energy-harvesting and self-powered sensing systems. [ABSTRACT FROM AUTHOR]

High performance is always the research objective in developing triboelectric nanogenerators (TENGs) for future versatile applications. In this study, a flexible ethyl cellulose/thermoplastic polyurethane (EC/TPU) nanofiber triboelectric layer with barium titanate (BTO) nanoparticles is proposed for high-performance TENGs, in which electrospun EC/TPU nanofiber membranes supply the high-roughness friction surfaces and piezoelectric BTO nanoparticles are further incorporated to boost the electric outputs by the synergistic effect of piezoelectricity and triboelectricity. Consequently, when the content of the BTO nanoparticle is 8 wt % in the EC/TPU (1:4 in weight ratio) nanofibers, the composite membrane displayed a stress of 9.25 MPa and a strain of 275.2%. The corresponding TENG achieves electric outputs of 125.8 V, 34.1 μA, and 1.68 W/m2, much higher than those of an individual piezoelectric nanogenerator or TENG. The TENGs are potentially used to supply energy for commercial LEDs and microelectronics and as self-powered sensors to monitor human physical training conditions. This research provides a guideline for developing TENGs with high performance, which is crucial for their long-term use. [ABSTRACT FROM AUTHOR]

Manganese oxidation is an important biogeochemical process that is largely regulated by bacteria through enzymatic reactions. However, the detailed mechanism is poorly understood due to challenges in isolating and characterizing these unknown enzymes. A manganese oxidase, Mnx, from Bacillus sp. PL-12 has been successfully overexpressed in active form as a protein complex with a molecular mass of 211 kDa. We have recently used surface induced dissociation (SID) and ion mobility-mass spectrometry (IM-MS) to release and detect folded subcomplexes for determining subunit connectivity and quaternary structure. The data from the native mass spectrometry experiments led to a plausible structural model of this multicopper oxidase, which has been difficult to study by conventional structural biology methods. It was also revealed that each Mnx subunit binds a variable number of copper ions. Becasue of the heterogeneity of the protein and limited mass resolution, ambiguities in assigning some of the observed peaks remained as a barrier to fully understanding the role of metals and potential unknown ligands in Mnx. In this study, we performed SID in a modified Fourier transform-ion cyclotron resonance (FTICR) mass spectrometer. The high mass accuracy and resolution offered by FTICR unveiled unexpected artificial modifications on the protein that had been previously thought to be iron bound species based on lower resolution spectra. Additionally, isotopically resolved spectra of the released subcomplexes revealed the metal binding stoichiometry at different structural levels. This method holds great potential for in-depth characterization of metalloproteins and protein-ligand complexes.ᅟ [ABSTRACT FROM AUTHOR]

Mass spectrometry continues to develop as a valuable tool in the analysis of proteins and protein complexes. In protein complex mass spectrometry studies, surface-induced dissociation (SID) has been successfully applied in quadrupole time-of-flight (Q-TOF) instruments. SID provides structural information on noncovalent protein complexes that is complementary to other techniques. However, the mass resolution of Q-TOF instruments can limit the information that can be obtained for protein complexes by SID. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolution and ultrahigh mass accuracy measurements. In this study, an SID device was designed and successfully installed in a hybrid FT-ICR instrument in place of the standard gas collision cell. The SID-FT-ICR platform has been tested with several protein complex systems (homooligomers, a heterooligomer, and a protein-ligand complex, ranging from 53 to 85 kDa), and the results are consistent with data previously acquired on Q-TOF platforms, matching predictions from known protein interface information. SID fragments with the same m/z but different charge states are well-resolved based on distinct spacing between adjacent isotope peaks, and the addition of metal cations and ligands can also be isotopically resolved with the ultrahigh mass resolution available in FT-ICR. [ABSTRACT FROM AUTHOR]