This article proposes a layered blockchain architecture based on partitioned IoT to reduce the scalability requirements of the Internet of Things for blockchain. In addition, in response to the problem of low performa...
This article proposes a layered blockchain architecture based on partitioned IoT to reduce the scalability requirements of the Internet of Things for blockchain. In addition, in response to the problem of low performance of traditional Byzantine fault-tolerant consensus algorithms such as PBFT in IoT scenarios, a parallel block verification Byzantine consensus algorithm (PVBFT) is proposed based on a layered blockchain architecture based on partitioned IoT. This algorithm improves the VRF lottery algorithm to select consensus nodes quickly, replaces single chain storage structure with DAG structure, introduces coordination nodes, and fully utilizes the high concurrency of DAG. We have implemented multi-node collision-free block packaging and multi-block parallel verification, using aggregation signature to reduce communication costs during the Byzantine consensus process and effectively improve the throughput of the consensus algorithm. The experimental results show that compared with the PBFT consensus algorithm, PVBFT has lower communication overhead and higher performance.
The purpose of this study was to examine the efficacy of the algicidal bacterium Sagittula stellata on the cell lysis of Nannochloropsis oceanica, a microalga found in the marine environment, in order to extract intra...
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The purpose of this study was to examine the efficacy of the algicidal bacterium Sagittula stellata on the cell lysis of Nannochloropsis oceanica, a microalga found in the marine environment, in order to extract intracellular valuables. Algicidal bacteria are capable of lysing algal cell walls while keeping lipids and proteins intact yet separated. We obtained these microbes from locations with consistent algae blooms and found that the bacterium Sagittula stellata displayed significant algicidal properties toward Nannochloropsis oceanica, achieving an algicidal rate of 80.1%. We detected a decrease of 66.2% in in vivo fluorescence intensity in algae cultures, obtained a recoverable crude lipid content of 23.3% and a polyunsaturated fatty acid (PUFA) ratio of 29.0% of bacteria-treated algae, and observed the lysis of the cell membrane and the structure of the nucleus of algae. We also identified the inhibited transcription of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (rbcS) gene and proliferating cell nuclear antigen (PCNA)-related genes and the upregulated heat shock protein (hsp) gene in algal cells during bacterial exposure. Our results indicate that Sagittula stellata effectively lysed microalgae cells, allowing the recovery of intracellular valuables. The algicidal method of Sagittula stellata on Nannochloropsis oceanica cells was confirmed to be a direct attack (or predation), followed by an indirect attack through the secretion of extracellular algicidal compounds. This study provides an important framework for the broad application of algicidal microorganisms in algal cell disruption and the production of intracellular valuables.
A mild, selective and redox-neutral Cp*Ir(iii)- and Cp*Rh(iii)-catalyzed C-H activation/annulation of salicylaldehydes with fluorovinyl tosylates is reported. The use of monofluorovinyl tosylate favors the synthesis o...
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A mild, selective and redox-neutral Cp*Ir(iii)- and Cp*Rh(iii)-catalyzed C-H activation/annulation of salicylaldehydes with fluorovinyl tosylates is reported. The use of monofluorovinyl tosylate favors the synthesis of C2- and C3-substitution-free chromones via C-H activation/beta-F elimination/annulation, whereas difluorovinyl tosylate leads to the construction of C2-fluoroalkoxy chromones. Mild reaction conditions and good functional-group tolerance were observed. Further functionalization of the resulting chromones via halogenation, alkynylation, alkylation and hydrocyanation was successfully realized.
Biochar is used for the removal of antibiotics from sewage, where microplastics are arising contaminants. However, whether adsorption capacity of microplastics for antibiotics and how different particle sizes and type...
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The performance of current nuclear medicine imaging systems is largely limited by the performance of detectors, and high spatial resolution detectors require high optical yield scintillator arrays. In this work, we si...
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The performance of current nuclear medicine imaging systems is largely limited by the performance of detectors, and high spatial resolution detectors require high optical yield scintillator arrays. In this work, we simulated and designed for the first time a distributed Bragg reflector (multilayer dielectric film) that covers the entire lutetium yttrium oxyorthosilicate emission spectral band and consists of three 1/4 wavelength (?/4) primary film systems centered at 420, 500, and 575 nm. In order to achieve ultrahigh reflectivity at the full incidence angle of the scintillator emitting surface, we propose a master optical configuration combining the dielectric film with a metal film/diffuse reflection adhesive. To explain this mechanism, we also simulated the change in reflectivity of the actual inner surface light collection. Experimental results show that a combination of a highly reflective reflector can achieve full-angle high reflectance at the total angle of incidence. We find that the dielectric film does not change the total reflection structure inside the crystal, while the light-blocking layer changes and increases the angular reflection of the dielectric film about the angle. These findings provide important insights into surface treatment as well as the design of scintillation crystal arrays, with far-reaching implications for high spatial resolution optical imaging systems.
alpha,alpha-Difluoromethyl carbinols are important structural motifs in many therapeutic agents and functional materials. Herein, we developed a sustainable and efficient method for the synthesis of a series of alpha,...
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alpha,alpha-Difluoromethyl carbinols are important structural motifs in many therapeutic agents and functional materials. Herein, we developed a sustainable and efficient method for the synthesis of a series of alpha,alpha-difluoromethyl carbinols from the remarkable Friedel-Crafts reaction of electron-rich arenes including indoles, phenols and anilines with easily accessible 2,2-difluorovinyl arylsulfonates in trifluoroethanol. This simple and straightforward protocol takes advantage of the readily accessible difluoroacetaldehyde in situ from 2,2-difluorovinyl arylsulfonate in a step-economical manner. Meanwhile, this transformation is distinguished by its wide substrate scope and excellent functional group tolerance. Preliminary mechanistic studies suggest that trifluoroethanol is crucial to this reaction.
The insufficient availability and activity of interfacial water remain a major challenge for alkaline hydrogen evolution reaction (HER). Here, we propose an "on-site disruption and near-site compensation" st...
The insufficient availability and activity of interfacial water remain a major challenge for alkaline hydrogen evolution reaction (HER). Here, we propose an "on-site disruption and near-site compensation" strategy to reform the interfacial water hydrogen bonding network via deliberate cation penetration and catalyst support engineering. This concept is validated using tip-like bimetallic RuNi nanoalloys planted on super-hydrophilic and high-curvature carbon nanocages (RuNi/NC). Theoretical simulations suggest that tip-induced localized concentration of hydrated K+ facilitates optimization of interfacial water dynamics and intermediate adsorption. In situ synchrotron X-ray spectroscopy endorses an H* spillover-bridged Volmer-Tafel mechanism synergistically relayed between Ru and Ni. Consequently, RuNi/NC exhibits low overpotential of 12 mV and high durability of 1600 h at 10 mA cm(-2) for alkaline HER, and demonstrates high performance in both water electrolysis and chlor-alkali electrolysis. This strategy offers a microscopic perspective on catalyst design for manipulation of the local interfacial water structure toward enhanced HER kinetics.
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