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This work provides an insight into the relationship between the structure and the function of bone at a multilevel under load, specifically the role of the ordered MCF arrays in the lamellar structure.Transition metal dichalcogenides (TMDs) have attracted wide attention due to their quasi-two-dimensional layered structure and exotic properties. Plenty of efforts have been done to modulate the interlayer stacking manner for novel states. However, as an equally important element in shaping the unique properties of TMDs, the effect of intralayer interaction is rarely revealed. Here, we report a particular case of pressure-tuned re-arrangement of intralayer atoms in distorted 1T-NbTe2, which was demonstrated to be a new type of structural phase transition in TMDs. The structural transition occurs in the pressure range of 16-20 GPa, resulting in a transformation of Nb atomic arrangement from the trimeric to dimeric structure, accompanied by a dramatic collapse of unit cell volume and lattice parameters. Simultaneously, a charge density wave (CDW) was also found to collapse during the phase transition. The strong increase in the critical fluctuations of CDW induces a significant decline in the electronic correlation and a change of charge carrier type from hole to electron in NbTe2. Our finding reveals a new mechanism of structure evolution and expands the field of pressure-induced phase transition.Triazole-based g-C3N5, a potential catalyst, has received little attention over the years. We prepared phosphorus-doped g-C3N5 with one triazole and two triazine units for the first time to investigate its photoelectrochemical (PEC) and photocatalytic properties. The doping states and crystalline structures of the samples were determined using X-ray techniques, namely, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption fine structure analysis. Our results suggested that the phosphorus was substituted into carbon sites form P-N/P═N bonds with four coordination, which contribute P 2p level donor states in the band gap to enhance light absorption and reduce charge separation. Therefore, P-doped g-C3N5 exhibited higher PEC current density and better photocatalytic efficiency toward the degradation of rhodamine B dye or tetracycline under light irradiation compared to the undoped g-C3N5 sample. However, excess phosphorus doping resulted in the formation of impurities and disrupted the triazine and triazole units, reducing the PEC and photocatalytic efficiency. In summary, P-doped g-C3N5 was successfully prepared in the present study and represents a promising, facile, and effective catalyst for energy applications and environmental remediation.With the rapid development in wearable electronics, self-powered devices have recently attracted tremendous attention to overcome the restriction of conventional power sources. In this regard, a simple, scalable, and one-pot electrospinning fabrication technique was utilized to construct an all-fiber-structured triboelectric nanogenerator (TENG). Ethyl cellulose was co-electrospun with polyamide 6 to serve as the triboelectric positive material, and a kind of strongly electronegative conductive material of MXene sheet was innovatively incorporated into poly(vinylidene fluoride) nanofiber to act as a triboelectric negative material. The assembled all-fiber TENG exhibited excellent durability and stability, as well as excellent output performance, which reached a peak power density of 290 mW/m2 at a load resistance of 100 MΩ. More importantly, the TENG was capable of harvesting energy to power various light-emitting diodes (LEDs) and monitoring human movements as a self-powered sensor, providing a promising application prospect in wearable electronics.HU is a bacterial nucleoid-associated protein. Two homologues, known as HU-A, and HU-B, are found in Escherichia coli within which the early, late, and stationary phases of growth are dominated by HU-AA, HU-BB, and HU-AB dimers, respectively. Here, using genetic manipulation, mass spectrometry, spectroscopy, chromatography, and electrophoretic examination of glutaraldehyde-mediated cross-linking of subunits, in combination with experiments involving mixing, co-expression, unfolding, and refolding of HU chains, we show that the spontaneous formation of HU-AB heterodimers that is reported to occur upon mixing of wild-type HU-AA and HU-BB homodimers does not occur if chains possess N-terminal extensions. We show that N-terminal extensions interfere with the conversion of homodimers into heterodimers. We also show that heterodimers are readily formed at anticipated levels by chains possessing N-terminal extensions in vivo, when direct chain-chain interactions are facilitated through production of HU-A and HU-B chains from proximal genes located upon the same plasmid. From the data, two explanations emerge regarding the mechanism by which N-terminal extensions happen to adversely affect the conversion of homodimers into heterodimers. (1) The disappearance of the α-amino group at HU's N-terminus impacts the intersubunit stacking of β-sheets at HU's dimeric interface, reducing the ease with which subunits dissociate from each other. Simultaneously, (2) the presence of an N-terminal extension appears to sterically prevent the association of HU-AA and HU-BB homodimers into a critically required, heterotetrameric intermediate (within which homodimers could otherwise exchange subunits without releasing monomers into solution, by remaining physically associated with each other).Ag(I)-insulin complex formation was investigated using electrospray quadrupole ion trap mass spectrometry (ESI-QIT-MS), and Ag(I) ion binding to an insulin molecule was evaluated. The Ag(I) binding ratios were measured in the range of pH 3-8. The highest binding ratio of the Ag(I) ions was obtained at pH 7. Spectrometric titration was carried out at varied molar ratios of Ag(I) ions to insulin from 20/1 to 250/1. It was observed that four Ag(I) ions were bound effectively to an insulin molecule to form Ag(I)1-4-insulin complexes. The formation equilibrium constants of Ag(I)1-4-insulin complexes were calculated from the ESI-QIT-MS peak intensities. The equilibrium constants were found as Kf1 = (2.92 ± 0.18) × 104 M-1, Kf2 = (1.03 ± 0.07) × 104 M-1, Kf3 = (6.67 ± 0.46) × 103 M-1, and Kf4 = (2.00 ± 0.16) × 103 M-1. The tandem MS/MS spectroscopies were studied to evaluate the stability of the Ag(I) complexes. The different flow rates with nano-ESI were performed to determine the binding of Ag(I) ions in solution or gas phase. In conclusion, it was observed that the Ag(I) ion forms stable Ag(I)1-4-complexes with high formation equilibrium constants.In recent years, deep molecular generative models have emerged as promising methods for de novo molecular design. Thanks to the rapid advance of deep learning techniques, deep learning architectures such as recurrent neural networks, variational autoencoders, and adversarial networks have been successfully employed for constructing generative models. Recently, quite a few metrics have been proposed to evaluate these deep generative models. However, many of these metrics cannot evaluate the chemical space coverage of sampled molecules. This work presents a novel and complementary metric for evaluating deep molecular generative models. SB273005 price The metric is based on the chemical space coverage of a reference dataset-GDB-13. The performance of seven different molecular generative models was compared by calculating what fraction of the structures, ring systems, and functional groups could be reproduced from the largely unseen reference set when using only a small fraction of GDB-13 for training. The results show that the performance of the generative models studied varies significantly using the benchmark metrics introduced herein, such that the generalization capabilities of the generative models can be clearly differentiated. In addition, the coverages of GDB-13 ring systems and functional groups were compared between the models. Our study provides a useful new metric that can be used for evaluating and comparing generative models.Sulfurized polyacrylonitrile (SPAN) is an attractive cathode candidate for the advanced lithium-sulfur (Li-S) batteries owing to its outstanding cyclic stability. Nevertheless, SPAN suffers from inadequate initial Coulombic efficiency (CE) induced by the sluggish reaction kinetics, which is primarily ascribed to the low Li-ion diffusivity and high electronic resistivity of the Li2S product. In this work, an optimal trace amount of soluble lithium polysulfide of Li2S8 is introduced as a redox mediator for a freestanding fibrous SPAN cathode to enhance the reversible oxidation efficiency of Li2S. During the delithiation process, the chemical interactions between Li2S and Li2S8 additive facilitate the electrochemical oxidation of Li2S, resulting in the transformation of not only C-S/S-S bonds in SPAN but also elemental sulfur. Benefiting from the synergistic effect of the two competing reactions, a high initial CE of 82.9% could be achieved at a current density of 200 mA g-1. Moreover, a superior capacity retention along with a high capacity of 1170 mAh g-1 up to the 400th cycle is available at 1000 mA g-1. The study offers a feasible approach for Li-S batteries toward the practical applications of SPAN.Every reader knows that an enzyme accelerates a reaction by reducing the activation-energy barrier. However, understanding how this is achieved by the structure of the enzyme and its interactions with stable complexes and transition states and, then, using this to (re)design enzymes to catalyze novel reactions remain the "holy grail" of mechanistic enzymology. The necessary foundation is the free-energy profile that specifies the energies of the bound substate, product, and intervening intermediates as well as the transition states by which they are interconverted. When this free-energy profile is compared to that for the uncatalyzed reaction, strategies for establishing and enhancing catalysis can be identified. This Perspective reminds readers that the first free-energy profile determined for an enzyme-catalyzed reaction, that for triosephosphate isomerase, was published in Biochemistry in 1976 by Jeremy R. Knowles, W. John Albery, and co-workers. They used the profile to propose three steps of increasing "subtlety" that can be influenced by evolutionary pressure to increase the flux through the reaction coordinate (1) "uniform binding" of the substrate, product, and intermediates; (2) "differential binding" of complexes so that these are isoenergetic (to minimize the energy of the intervening transition states); and (3) "catalysis of an elementary step" in which the transition state for the kinetically significant chemical step is stabilized so that flux can be determined by the rate of substrate binding or product dissociation. These papers continue to guide mechanistic studies of enzyme-catalyzed reactions and provide principles for the (re)design of novel enzymes.Cyanobacteria are promising microbial hosts for the production of diverse biofuels and biochemicals. However, compared to other model microbial hosts such as Escherichia coli and yeast, it takes a long time to genetically modify cyanobacteria. One way to efficiently engineer cyanobacteria while minimizing genetic engineering would be to develop a fast, high-throughput prototyping tool for cyanobacteria. In this study, we developed a CRISPR/Cas12a-based assay coupled with cyanobacteria cell-free systems to rapidly prototype promoter characteristics. Using this newly developed assay, we demonstrated cyanobacteria cell-free transcription for the first time and confirmed a positive correlation between the in vitro and in vivo transcription performance. Furthermore, we generated a synthetic promoter library and evaluated the characteristics of promoter subregions by using the assay. Varied promoter strength derived from random mutations were rapidly and effectively measured in a high-throughput way. We believe that this study offers an easily applicable and rapid prototyping platform to characterize promoters for cyanobacterial engineering.
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