Crack detection plays a critical role in ensuring road safety and maintenance. Traditional, manual, and semi-automatic detection methods have proven inefficient. Nowadays, the emergence of deep ...learning techniques has opened up new possibilities for automatic crack detection. However, there are few methods with both localization and segmentation abilities, and most perform poorly. The consistent nature of pavement over a small mileage range gives us the opportunity to make improvements. A novel data-augmentation strategy called CrackMover, specifically tailored for crack detection methods, is proposed. Experiments demonstrate the effectiveness of CrackMover for various methods. Moreover, this paper presents a new instance segmentation method for crack detection. It adopts a redesigned backbone network and incorporates a cascade structure for the region-based convolutional network (R-CNN) part. The experimental evaluation showcases significant performance improvements achieved by these approaches in crack detection. The proposed method achieves an average precision of 33.3%, surpassing Mask R-CNN with a Residual Network 50 backbone by 8.6%, proving its effectiveness in detecting crack distress.
Intestinal IgA, which is regulated by gut microbiota, has a crucial role in maintenance of intestinal homeostasis and in protecting the intestines from inflammation. However, the means by which ...microbiota promotes intestinal IgA responses remain unclear. Emerging evidence suggests that the host can sense gut bacterial metabolites in addition to pathogen-associated molecular patterns and that recognition of these small molecules influences host immune response in the intestines and beyond. We reported here that microbiota metabolite short-chain fatty acid acetate promoted intestinal IgA responses, which was mediated by "metabolite-sensing" GPR43. GPR43
mice demonstrated lower levels of intestinal IgA and IgA
gut bacteria compared with those in wild type (WT) mice. Feeding WT but not GPR43
mice acetate but not butyrate promoted intestinal IgA response independent of T cells. Acetate promoted B-cell IgA class switching and IgA production in vitro in the presence of WT but not GPR43
dendritic cells (DCs). Mechanistically, acetate-induced DC expression of Aldh1a2, which converts Vitamin A into its metabolite retinoic acid (RA). Moreover, blockade of RA signaling inhibited the acetate induction of B-cell IgA production. Our studies thus identified a new pathway by which microbiota promotes intestinal IgA response through its metabolites.
Iturins, which belong to antibiotic cyclic lipopeptides mainly produced by Bacillus sp., have the potential for application in biomedicine and biocontrol because of their hemolytic and antifungal ...properties. Bacillus amyloliquefaciens LL3, isolated previously by our lab, possesses a complete iturin A biosynthetic pathway as shown by genomic analysis. Nevertheless, iturin A could not be synthesized by strain LL3, possibly resulting from low transcription level of the itu operon.
In this work, enhanced transcription of the iturin A biosynthetic genes was implemented by inserting a strong constitutive promoter C2up into upstream of the itu operon, leading to the production of iturin A with a titer of 37.35 mg l
. Liquid chromatography-mass spectrometry analyses demonstrated that the strain produced four iturin A homologs with molecular ion peaks at m/z 1044, 1058, 1072 and 1086 corresponding to C
+ 2H
, C
+ 2H
, C
+ 2H
and C
+ 2H
. The iturin A extract exhibited strong inhibitory activity against several common plant pathogens. The yield of iturin A was improved to 99.73 mg l
by the optimization of the fermentation conditions using a response surface methodology. Furthermore, the yield of iturin A was increased to 113.1 mg l
by overexpression of a pleiotropic regulator DegQ.
To our knowledge, this is the first report on simultaneous production of four iturin A homologs (C
-C
) by a Bacillus strain. In addition, this study suggests that metabolic engineering in combination with culture conditions optimization may be a feasible method for enhanced production of bacterial secondary metabolites.
The cutting efficiency and wear of tunnel boring machine (TBM) cutters are two important parameters commonly used to estimate the boring performance and lifetime of the TBM in the tunneling process. ...These problems have been investigated by several researchers, whereas the influence of jointed rock mass and mixed ground condition on the cutting efficiency and cutter wear remains insufficiently understood. This study aims to elucidate the influence of rock mass and ground parameters on the cutting efficiency and cutter wear of the TBM by conducting a series of newly developed rolling boring tests on prefabricated joint sandstone samples with different orientations, spacings, and interlayers. Moreover, a numerical simulation is implemented through ANSYS software to verify the rationality of experimental results. The experimental and numerical results indicate that the optimal joint orientation is 30° for the TBM to intrude into a jointed rock mass. As joint spacing increases, the cutting efficiency decreases and the cutter wear increases. Furthermore, specific energy (
S
E
) and cutter wear simultaneously reach their maximum values when the rock abrasivity index (RAI) is 60. Both the specific energy and cutter wear decrease with increasing specific strength. For the rock mass with a soft interlayer in mixed ground, the optimal dip angle is 45°. Additionally, the fitting formulas of
S
E
and cutter wear in mixed ground are proposed to quantitatively illustrate the effect of RAI and interlayer strength on the cutting efficiency and cutter wear. The present study provides an improved understanding of rock-breaking mechanics, thereby making it possible for designers to adjust their design to enhance the TBM cutting efficiency.
Polyhydroxyalkanoate (PHA) can be produced by microorganisms from renewable resources and is regarded as a promising bioplastic to replace petroleum-based plastics. Pseudomonas mendocina NK-01 is a ...medium-chain-length PHA (mcl-PHA)-producing strain and its whole-genome sequence is currently available. The yield of mcl-PHA in P. mendocina NK-01 is expected to be improved by applying a promoter engineering strategy. However, a limited number of well-characterized promoters has greatly restricted the application of promoter engineering for increasing the yield of mcl-PHA in P. mendocina NK-01. In this work, 10 endogenous promoters from P. mendocina NK-01 were identified based on RNA-seq and promoter prediction results. Subsequently, 10 putative promoters were characterized for their strength through the expression of a reporter gene gfp. As a result, five strong promoters designated as P4, P6, P9, P16 and P25 were identified based on transcriptional level and GFP fluorescence intensity measurements. To evaluate whether the screened promoters can be used to enhance transcription of PHA synthase gene (phaC), the three promoters P4, P6 and P16 were separately integrated into upstream of the phaC operon in the genome of P. mendocina NK-01, resulting in the recombinant strains NKU-4C1, NKU-6C1 and NKU-16C1. As expected, the transcriptional levels of phaC1 and phaC2 in the recombinant strains were increased as shown by real-time quantitative RT-PCR. The phaZ gene encoding PHA depolymerase was further deleted to construct the recombinant strains NKU-∆phaZ-4C1, NKU-∆phaZ-6C1 and NKU-∆phaZ-16C1. The results from shake-flask fermentation indicated that the mcl-PHA titer of recombinant strain NKU-∆phaZ-16C1 was increased from 17 to 23 wt% compared with strain NKU-∆phaZ. This work provides a feasible method to discover strong promoters in P. mendocina NK-01 and highlights the potential of the screened endogenous strong promoters for metabolic engineering of P. mendocina NK-01 to increase the yield of mcl-PHA.
Adverse impacts of immunity in terrestrial non-target organisms exposed to neonicotinoid insecticides have been reported, but the causal link between insecticide exposure and possible immune ...alterations in fish remains limited. In the present study, the potential genotoxicity and immunotoxicity of three neonicotinoids (imidacloprid, nitenpyram, and dinotefuran) were assessed in Chinese rare minnows by using a 60-day chronic toxicity test. The hematological and biochemical parameters of juvenile Chinese rare minnows and changes in the transcription of six inflammation-related genes were determined after exposure to neonicotinoids at 0.1, 0.5, or 2.0 mg/L. A clear difference in the frequency of erythrocytes with micronuclei (MN) was observed after treatment with 2.0 mg/L imidacloprid (p < .05). Additionally, exposure to 0.5 or 2.0 mg/L imidacloprid significantly increased the binucleated (BN) erythrocytes and those with notched nuclei (NT) (p < .05). A serum protein electrophoresis (SPE) assay showed significant alterations in the serum protein in all treatments (p < .05), and further analysis indicated decreases in immunoglobulin (Ig) in treatments with 0.5 or 2.0 mg/L imidacloprid or dinotefuran or with 0.1 mg/L nitenpyram (p < .05). Moreover, a biochemical assay confirmed that immunoglobulin M (IgM) levels were indeed significantly decreased upon treatment with imidacloprid or dinotefuran at 0.5 or 2.0 mg/L (p < .05). In addition, the transcriptional levels of the inflammatory cytokines IL-6, INF-α, TNF-α, and IL-1β were markedly down-regulated after all imidacloprid treatments (p < .05), whereas the expression levels of only TNF-α and IL-1β were significantly down-regulated following the 0.5 and 2.0 mg/L dinotefuran treatments (p < .05). Taken together, our results clearly demonstrate that imidacloprid, rather than nitenpyram and dinotefuran, can induce genotoxicity. The responsiveness of these immune indicators provides new insight into and evidence of the adverse effects of neonicotinoids on aquatic non-target organisms.
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•Imidacloprid, but not nitenpyram and dinotefuran, can induce genotoxicity in aquatic fish.•The SPE assay indicated that chronic neonics exposure triggered an immune system related protein response in fish serum.•Transcript levels of inflammatory cytokines and chemokines are more sensitive to imidacloprid and dinotefuran.•Chronic imidacloprid and dinotefuran exposure might significantly decreases the immune system of juvenile fish.
This study increases the understanding of the potential genotoxicity and immunotoxicity of neonicotinoids toward aquatic non-target organisms.
The isoflavone malonyltransferase GmMaT2 is involved in rhizobia–root interaction and nodulation. It catalyzes the malonylation of isoflavone glucosides in soybean roots and affects isoflavonoid ...secretion in root exudates, thereby modifying Nod factor induction.
Abstract
Malonyl-CoA:flavonoid acyltransferases (MaTs) modify isoflavones, but only a few have been characterized for activity and assigned to specific physiological processes. Legume roots exude isoflavone malonates into the rhizosphere, where they are hydrolyzed into isoflavone aglycones. Soybean GmMaT2 was highly expressed in seeds, root hairs, and nodules. GmMaT2 and GmMaT4 recombinant enzymes used isoflavone 7-O-glucosides as acceptors and malonyl-CoA as an acyl donor to generate isoflavone glucoside malonates. GmMaT2 had higher activity towards isoflavone glucosides than GmMaT4. Overexpression in hairy roots of GmMaT2 and GmMaT4 produced more malonyldaidzin, malonylgenistin, and malonylglycitin, and resulted in more nodules than control. However, only GmMaT2 knockdown (KD) hairy roots showed reduced levels of malonyldaidzin, malonylgenistin, and malonylglycitin, and, likewise, reduced nodule numbers. These were consistent with the up-regulation of only GmMaT2 by rhizobial infection, and higher expression levels of early nodulation genes in GmMaT2- and GmMaT4-overexpressing roots, but lower only in GmMaT2-KD roots compared with control roots. Higher malonyl isoflavonoid levels in transgenic hairy roots were associated with higher levels of isoflavones in root exudates and more nodules, and vice versa. We suggest that GmMaT2 participates in soybean nodulation by catalyzing isoflavone malonylation and affecting malonyl isoflavone secretion for activation of Nod factor and nodulation.
•The performance of HPSB hydrogen storage system was studied using Pr6O11/CoCl2 and Sm2O3/CoCl2 as catalysts.•There was a direct connection between the amount of hydrogen released and catalyst.•TiO2 ...has an important influence on the hydrogen storage performance of the hydrogen storage system.•There was a direct connection between microstructure and amount of hydrogen.
This work studied a hydrogen storage material which could absorbed hydrogen under room temperature and 3 MPa hydrogen pressure. This material was obtained by hydrolysis of NaBH4 (HPSB) and the hydrogen absorption and desorption performance was tested by PCT apparatus. The results showed that mixed-catalysts affected significantly the hydrogen storage capacity of the HBSP. When ratio of the catalysts Pr6O11 and CoCl2 was 7:3, the maximum hydrogen released amount of the HPSB(Pr6O11) hydrogen storage system reached 1.35 wt%.
In order to improve the hydrogen absorption and desorption performance, TiO2 as catalyst were added to the HPSB(Pr6O11) hydrogen storage system. The results show when the catalysts Pr6O11 to CoCl2 doped ratio was 7:3 and the amount of TiO2 accounts for 9 wt% of the hydrogen storage system, the maximum hydrogen released of the HPSB(Pr6O11)-TiO2 hydrogen storage system reached 1.78 wt%. TiO2 obviously improve the hydrogen storage performance of HPSB hydrogen storage system.
Compression tests of Mg–Gd–Y–Nd–Zr alloy have been performed in the compression temperature range from 623K to 803K and the strain rate range from 0.005s−1 to 5s−1. The high temperature deformation ...behavior was characterized based on an analysis of the stress–strain behavior, kinetics and processing map. The constitutive equation of the Mg–Gd–Y–Nd–Zr alloy is established, which describes the flow stress as a function of the strain rate and deformation temperature. The average apparent activation energy for hot deformation is calculated to be 250.0kJ/mol. Based on the dynamic material model and the Prasad's instability criterion, the processing maps for the alloy are constructed at strains of 0.1 and 0.7. The processing map developed at strain of 0.7 exhibits two domains with higher value of power dissipation: one occurring in the temperature range of 720–760K and in the strain rate range of 0.005–0.01s−1, which is associated with dynamic recrystallization and dynamic precipitation; the other occurring in the temperature range of 760–803K and strain rate range of 0.01–0.5s−1. According to the processing map and microstructure observation, the optimum hot working condition for Mg–Gd–Y–Nd–Zr alloy is determined to be 773K and 0.05s−1.
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