This paper presents the modeling technique, design method, a new working mechanism and influence factors for elastic metamaterials (EMs) with parallel multi-resonators for broadband elastic vibration suppression. The general formula of the effective mass is deduced, and the effects of the relevant structural parameters on the frequency regions of the negative effective mass are illustrated in details. Subsequently, the dispersion relation and transmission spectrum of the EMs are studied. Based on the theoretical approach, the EMs plates were proposed, and the formation mechanism of the band gaps are analyzed by studying the displacement field of the eigenmodes at the band gaps edges. The related results well confirm that the novel EMs induces multi-frequency negative effective mass, and the number of the regions is equal to the number of the local resonators. The start frequencies of the band gaps are decided by the natural frequencies of each resonator, and the width of frequency band with negative effective mass can be broadened by enlarging the mass ratio of the local resonator. The EMs plate with the thickness of only 2.5 mm designed on the basis of theoretical research exhibits two flexural vibration band gaps (FVBGs) with the total width of 78.4 Hz below 200 Hz, which has been verified by the transmission testing experiments. For the formation mechanism of the FVBGs, the vibration is localized in the according resonator at the lower edge of each band gap, while at the upper edges the local resonance mass and the base plate vibrate in a reverse phase. Based on the theoretical and numerical analyses, the EMs with multiple parallel local resonators would be used in various fields, such as noise and vibration isolation, filters, and other renewed devices.

Machine learning plays an important role in computational intelligence and has been widely used in many engineering fields. Surface voids or bugholes frequently appearing on concrete surface after the casting process make the corresponding manual inspection time consuming, costly, labor intensive, and inconsistent. In order to make a better inspection of the concrete surface, automatic classification of concrete bugholes is needed. In this paper, a variable selection strategy is proposed for pursuing feature interpretability, together with an automatic ensemble classification designed for getting a better accuracy of the bughole classification. A texture feature deriving from the Gabor filter and gray-level run lengths is extracted in concrete surface images. Interpretable variables, which are also the components of the feature, are selected according to a presented cumulative voting strategy. An ensemble classifier with its base classifier automatically assigned is provided to detect whether a surface void exists in an image or not. Experimental results on 1000 image samples indicate the effectiveness of our method with a comparable prediction accuracy and model explicable.

Autotrophic nitrification is regulated by canonical ammonia-oxidizing archaea (AOA) and bacteria (AOB) and nitrite-oxidizing bacteria (NOB). To date, most studies have focused on the role of canonical ammonia oxidizers in nitrification while neglecting the NOB. In order to understand the impacts of combined biochar and chemical fertilizer addition on nitrification and associated nitrifiers in plant rhizosphere soil, we collected rhizosphere soil from a maize field under four different treatments: no fertilization (CK), biochar (B), chemical nitrogen (N) + phosphorus (P) + potassium (K) fertilizers (NPK), and biochar + NPK fertilizers (B + NPK). The potential nitrification rate (PNR), community abundances, and structures of AOA, AOB, complete ammonia-oxidizing bacteria (Comammox Nitrospira clade A), and Nitrobacter- and Nitrospira-like NOB were measured. Biochar and/or NPK additions increased soil pH and nutrient contents in rhizosphere soil. B, NPK, and B + NPK treatments significantly stimulated PNR and abundances of AOB, Comammox, and Nitrobacter- and Nitrospira-like NOB, with the highest values observed in the B + NPK treatment. Pearson correlation and random forest analyses predicted more importance of AOB, Comammox Nitrospira clade A, and Nitrobacter- and Nitrospira-like NOB abundances over AOA on PNR. Biochar and/or NPK additions strongly altered whole nitrifying community structures. Redundancy analysis (RDA) showed that nitrifying community structures were significantly affected by pH and nutrient contents. This research shows that combined application of biochar and NPK fertilizer has a positive effect on improving soil nitrification by affecting communities of AOB and NOB in rhizosphere soil. These new revelations, especially as they related to understudied NOB, can be used to increase efficiency of agricultural land and resource management.

This study explored the effects of combined urea and 3,4-dimethylpyrazole phosphate (DMPP) on several components critical to the soil system: net nitrification rates; communities of targeted ammonia oxidizers [ammonia-oxidizing archaea (AOA) and bacteria (AOB) and complete ammonia-oxidizing bacteria (comammox)]; non-targeted nitrite-oxidizing bacteria (NOB) and bacteria. We conducted the study in two contrasting soils (acidic and neutral) over the course of 28 days. Our results indicated that DMPP had higher inhibitory efficacy in the acidic soil (30.7%) compared to the neutral soil (12.1%). The abundance of AOB and Nitrospira-like NOB were positively associated with nitrate content in acidic soil. In neutral soil, these communities were joined by the abundance of AOA and Nitrobacter-like NOB in being positively associated with nitrate content. By blocking the growth of AOB in acidic soil—and the growth of both AOB and comammox in neutral soil—DMPP supported higher rates of AOA growth. Amplicon sequencing of the 16S rRNA gene revealed that urea and urea + DMPP treatments significantly increased the diversity indices of bacteria, including Chao 1, ACE, Shannon, and Simpson in the acidic soil but did not do so in the neutral soil. However, both urea and urea + DMPP treatments obviously altered the community structure of bacteria in both soils relative to the control treatment. This experiment comprehensively analyzed the effects of urea and nitrification inhibitor on functional guilds involved in the nitrification process and non-targeted bacteria, not just focus on targeted ammonia oxidizers.

The function of proteins depends on their phase behavior. When the concentration of a protein exceeds a critical value, it may undergo liquid‐liquid phase separation, leading to demixing of proteins from solution. The resulted liquid droplets are dense and protein‐rich. The microtubule associated protein tau can enrich tubulin by forming liquid droplets, which promotes the formation of microtubule bundles. On the other hand, aberrant aggregation of Tau into neurofibrillary tangles correlates with the progressive destruction of nerve cells. Therefore, studying the aggregating mechanism of tau and drug design targeting tau fibrils are critical for the therapy of Alzheimer's disease. Recent studies have shown that lysine acetylation plays an important role in modulating tau aggregation and microtubule assembly. Considering the potential correlations between liquid‐liquid phase separation and amyloid formation, here we investigated the effect of lysine acetylation on the phase behavior and function of tau in vitro. We used site‐directed mutagenesis, light scattering, thioflavin T florescence assay, and microrheology to study the liquid‐liquid phase separation and aggregation of tau. Consistent with previous observations, acetylation on K274/K321 (mimicked by K274Q/K321Q) significantly impaired tau aggregation whereas acetylation on K280/K281/K369 (mimicked by K280Q/K281Q/K369Q) significantly promoted tau filament formation as compared with the WT protein. Although acetylation on K274/K321 and K280/K281/K369 differentially affected tau aggregation, both acetylation patterns promoted liquid‐liquid phase separation of tau. Moreover, microrheology characterization and protein concentration determination showed that the droplets formed by acetylated tau were denser than the WT protein, suggesting that more intermolecular interactions were form upon lysine acetylation. These results show that lysine residues within the MT‐binding repeats regulate the phase behavior of tau via complex interactions.Support or Funding InformationThis work was supported by National Natural Science Foundation of China (Grant number: 21603121) and Hubei University of Technology.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

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