Synchronized maturation has been extensively studied in biological science on its evolutionary advantages. This paper is devoted to the study of the spatial dynamics of species growth with annually ...synchronous emergence of adults by formulating an impulsive reaction–diffusion model. With the aid of the discrete-time semiflow generated by the 1-year solution map, we establish the existence of the spreading speed and traveling waves for the model on an unbounded spatial domain. It turns out that the spreading speed coincides with the minimal speed of traveling waves, regardless of the monotonicity of the birth rate function. We also investigate the model on a bounded domain with a lethal exterior to determine the critical domain size to reserve species persistence. Numerical simulations are illustrated to confirm the analytical results and to explore the effects of the emergence maturation delay on the spatial dynamics of the population distribution. In particular, the relationship between the spreading speed and the emergence maturation delay is found to be counterintuitively variable.
Bactrocera dorsalis (Hendel) is a fruit-eating pest that causes substantial economic damage to the fresh produce industry in tropical and sub-tropical countries. Methyl eugenol (ME) is a powerful ...attractant for mature males of B. dorsalis, and has been widely used for detecting, luring and eradicating B. dorsalis populations worldwide. However, the molecular mechanism underlying the olfactory perception of ME remains largely unknown. Here, we analyzed the differential proteomics profiling of the antennae between ME-responsive and ME-non-responsive males by using isobaric tags for relative and absolute quantitation (iTRAQ). In total, 4622 proteins were identified, of which 277 proteins were significant differentially expressed, with 192 up-regulated and 85 down-regulated in responsive male antennae. Quantitative real-time PCR (qRT-PCR) analysis confirmed the authenticity and accuracy of the proteomic analysis. Based on the iTRAQ and qRT-PCR results, we found that the odorant-binding protein 2 (BdorOBP2) was abundantly expressed in responsive male antennae. Moreover, BdorOBP2 was significantly up-regulated by ME in male antennae. Mature males showed significantly greater taxis toward ME than did mature females. Silencing BdorOBP2 reduced mature males' responsiveness to ME. These results indicate that BdorOBP2 may play an essential role in the molecular mechanism underlying B. dorsalis olfactory perception of ME.
To analyze the spatiotemporal dynamic distribution and detect the related meteorological factors of scarlet fever from an ecological perspective, which could provide scientific information for ...effective prevention and control of this disease.
The data on scarlet fever cases in mainland China were downloaded from the Data Center of the China Public Health Science, while monthly meteorological data were extracted from the official website of the National Bureau of Statistics. Global Moran's I, local Getis-Ord Gi⁎ hotspot statistics, and Kulldorff's retrospective space-time scan statistical analysis were used to detect the spatial and spatiotemporal clusters of scarlet fever across all settings. A spatial panel data model was conducted to estimate the impact of meteorological factors on scarlet fever incidence.
Scarlet fever in China had obvious spatial, temporal, and spatiotemporal clustering, high-incidence spatial clusters were located mainly in the north and northeast of China. Nine spatiotemporal clusters were identified. A spatial lag fixed effects panel data model was the best fit for regression analysis. After adjusting for spatial individual effects and spatial autocorrelation (ρ = 0.5623), scarlet fever incidence was positively associated with a one-month lag of average temperature, precipitation, and total sunshine hours (all P-values < 0.05). Each 10 °C, 2 cm, and 10 h increase in temperature, precipitation, and sunshine hours, respectively, was associated with a 6.41% increment and 1.04% and 1.41% decrement in scarlet fever incidence, respectively.
The incidence of scarlet fever in China showed an upward trend in recent years. It had obvious spatiotemporal clustering, with the high-risk areas mainly concentrated in the north and northeast of China. Areas with high temperature and with low precipitation and sunshine hours tended to have a higher scarlet fever incidence, and we should pay more attention to prevention and control in these places.
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•Exploratory spatiotemporal analysis methods were used to detect the spatiotemporal clusters of scarlet fever.•Scarlet fever in mainland China has shown an upward trend in recent years, with obvious spatiotemporal clustering.•The spatial panel data models were used to estimate the relationships between meteorological factors and scarlet fever.•Average temperature, precipitation, and total sunshine hours, have a significant impact on scarlet fever incidence.
Invited for the cover of this issue are Xiao‐Yu Yang and co‐workers at Wuhan University of Technology, Heinrich‐Heine‐Universität Düsseldorf, University of the Witwatersrand, and Ben‐Gurion ...University of the Negev. The image depicts Ti vacancies in TiO2 as powerful drivers of photo‐ and photo‐electrocatalytic seawater splitting for hydrogen production. Read the full text of the article at 10.1002/chem.202101817.
“We think this can provide new insight into the design of high‐performance catalysts for seawater splitting.” Read more about the story behind the cover in the Cover Profile and about the research itself on page 14202 ff. (DOI: 10.1002/chem.202101817).
Low-temperature catalytic reforming of volatiles and nitrogen compounds from sewage sludge (SS) pyrolysis was performed in a two-stage fixed-bed reactor over Ni/Al sub(2)O sub(3) under inert and ...steam-reforming conditions. The results show that the reforming of SS volatiles significantly depended on temperature, space velocity, steam partial pressure, and feedstock type. Catalytic cracking of SS volatiles at 650 degreesC under inert atmosphere produced a tar-free synthetic gas with a H sub(2)/CO ratio of 2:1 in a high yield, which is preferred for maximum conversion efficiency for methanol synthesis. Steam as the gasifying agent gave a H sub(2)-rich gas (H sub(2) content 68.0 vol.SK) with a high yield of 82.5 mmol times g super(-1) (daf) at 650 degreesC, while the H sub(2) yield is twice as that from non-steam gasification. Ni/Al sub(2)O sub(3) effectively improved tar reforming and showed great resistance to coke deposition in the presence of steam. NH sub(3), HCN, and nitrogen in tar are the main volatile nitrogen species in SS pyrolysis. Al-most all the NO sub(x) precursors were converted to N sub(2) by catalytic reforming at 650 degreesC both in the presence and absence of steam. Such an approach may lead to the development of a clean SS utilization technology and also H sub(2)/ synthetic gas production technology from SS.
•Fertilization accelerated soil acidification by promoting nitrification, NO3– leaching and plant growth.•Plant played an important role in soil acidification by redistributing soil base cations ...pool.•Straw returning was recommended to alleviate acidification of acid sensitive soils.•Two-year fertilization significantly increased soil exchangeable H+ and Al3+.
Increasing acid deposition and intense nitrogen (N) fertilization have resulted in severe soil acidification in many regions of the world. However, the soil acidification rate, especially quantitative contributions of different proton (H+) sources remain unclear in various cropping systems. In this study, a two-year field lysimeter experiment was conducted with a set of different N fertilization treatments (0, 100, 200 and 400 kg N ha−1 yr−1) for maize crop in typical red soil in subtropical China. The pathways and budgets of different H+ sources were quantified by calculating the input–output balance of major elements. Results showed that fertilization significantly accelerated soil acidification by increasing the leaching of NO3– and base cations (K+, Ca2+, Na+, and Mg2+) as well as increasing the cation removals by plant uptake and harvest. Unbalanced plant uptake of anions and cations was the primary H+ source (64.4–80.5%) to soils. Plants have an important effect on soil acidification by redistributing cations in soils. Due to cation removals by plant uptake and harvest, there were significant decreases of soil exchangeable base cations under high urea-N treatments (200 and 400 kg N ha−1 yr−1) and significant increases of soil exchangeable H+ and Al3+ under three fertilization treatments. Of course, N transformation also plays an important role (12.1% to 38.8%). However, the effect of direct H+ deposition is minor in this area comparatively (5.78% to 7.34%). Quantification of acidification contribution of different sources is useful for the establishment of further soil remediation practices. The field management is considered very important to alleviate soil acidification, including increasing straw return and controlling fertilizer application.
Bladder cancer (BCa) is an aggressive malignancy because of its distant metastasis and high recurrence rate. Circular RNAs (circRNAs) exert critical regulatory functions in cancer progression. ...However, the expression patterns and roles of circRNAs in BCa have not been well investigated. In this study, we first screened circRNA expression profiles using a circRNA microarray of paired BCa and normal tissues, and the expression of circST6GALNAC6 was confirmed by qRT-PCR and fluorescence in situ hybridization (FISH). MTT, colony formation and Transwell assays were performed to measure cell proliferation, migration and invasion. We investigated the regulatory effect of circST6GALNAC6 on miRNA and its target genes to explore the potential regulatory mechanisms of circST6GALNAC6 by chromatin immunoprecipitation (ChIP), RNA immunoprecipitation (RIP), MS2-tagged RNA affinity purification (MS2-TRAP), immunofluorescence (IF) and dual luciferase activity assays. A nude mouse xenograft model was used to examine the functions of circST6GALNAC6/STMN1 in tumour metastasis in vivo. We found that 881 circRNAs were significantly dysregulated in BCa tissues compared to normal tissues. circST6GALNAC6(hsa_circ_0088708) was downregulated in BCa tissues and cells. Overexpression of circST6GALNAC6 effectively inhibited the cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) in vitro and suppressed BCa metastasis in vivo. Mechanistically, we showed that the SP1 transcription factor, which binds to the circST6GALNAC6 mRNA transcript, activates circST6GALNAC6 transcription. Next, we verified that circST6GALNAC6 serves as a sponge that directly binds miR-200a-3p to regulate stathmin (STMN1) expression. Furthermore, we found that STMN1 is involved in circST6GALNAC6/miR-200a-3p axis-regulated BCa EMT and metastasis. Thus, our findings indicate an important underlying mechanism in BCa metastasis by which SP1-induced circST6GALNAC6 sponges miR-200a-3p to promote STMN1/EMT signalling. This mechanism could provide pivotal potential prognostic biomarkers and therapeutic targets for BCa.
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