Triple-negative breast cancer (TNBC) is a specific type of breast cancer with poor overall survival (OS) time. Previous studies revealed that microRNAs (miRNAs/miRs) serve important roles in the pathogenesis, progression and prognosis of TNBC. The present study analyzed the miRNA expression and clinical data of patients with TNBC downloaded from The Cancer Genome Atlas. A total of 194 differentially expressed miRNAs were identified between TNBC and matched normal tissues using the cut-off criteria of P<0.05 and |log2 fold change|>2. Of these miRNAs, 65 were downregulated and 129 were upregulated. Using Kaplan-Meier survival analysis, a total of 77 miRNAs that were closely associated with OS time were identified (P<0.05). The intersection of the 77 miRNAs and 194 differentially expressed miRNAs revealed six miRNAs. Log-rank tests based on survival curves were performed and two miRNAs were eliminated. The prognostic value of the remaining four miRNAs was evaluated with a Cox proportional hazards model using multiple logistic regression with forward stepwise selection of variables. Three miRNAs (miR-21-3p, miR-659-5p and miR-200b-5p) were subsequently identified as independent risk factors associated with OS time in the model. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses revealed that the target genes of these three miRNAs were mainly involved in ‘cell protein metabolism’, ‘RNA transcriptional regulation’, ‘cell migration’, ‘MAPK signaling pathway’, ‘ErbB signaling pathway’, ‘prolactin signaling pathway’ and ‘adherens junctions’. Taken together, the results obtained in the present study suggested that the three-miRNA signature may serve as a prognostic biomarker for patients with TNBC.

In order to realize the high-quality row seeding operation with unmanned aerial vehicle (UAV) in paddy field, a shot seeding device that can sow five rows of pelleted rice seeds at the same time was designed. The shot seeding device mainly consists of an external grooved wheel seed metering device and five shot seeding modules. The designed external grooved wheel seed metering device can take the seeds out of the seed box and divide the seeds into five parts. The shot seeding module can accelerate the pelleted rice seeds to reduce the impact of the UAV wind on the direction of seed movement. Furthermore, an angle adjustment mechanism for the shot seeding module was used to change the row spacing. The seed metering device test verified that when the speed of the seed metering wheel was 15 r/min, the coefficient of variation of the discharge rate of each row (C.V 1 ) and total seed discharge rate stability (C.V 2 ) were 1.70% and 1.04%, respectively. Image processing technique was used to test the UAV seeding performance. The distribution characteristics of seeds on the ground showed that the number of seeds in each row gradually increased from both sides to the middle in the width direction. According to the statistics, there were 60%-70% of the seeds in each row in the 100 mm width range. The field test showed that when the working height was 1.5 m and the seeding quantity was 38.56 kg/hm 2 , the performance of sowing in rows was obvious, the deviation rate of seeding quantity was 1.89%. After 16 d of sowing, the seeds' emergence rate was stable, and the average emergence rate was 82.63% and the yield was 6775.50 kg/hm 2 .

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The reaction process of alkali‐activated carbonatite and the dissolution rate of carbonatite with different content of MgO in water glass solution were studied in this paper by means of in‐situ technologies, that is, polarizing microscope (PM) and digital holographic microscope (DHM). The volume change of carbonatite particles as a function of dissolution time was also quantified by using DHM. The results show that the dissolution rate of carbonatites decreases as the increase of Mg content (from 0 to 21.6 wt. %) in carbonatites. The average dissolution rate of carbonatite with a MgO content of 11.37 wt. % in water glass (M = 1.6, c = 35%) is 75.33 μm3/h within the first 12 hr of dissolution. Both dedolomitization and alkali‐silica reaction are present in the alkali‐activated carbonatite system. The Mg‐carbonatite tends to dedolomitize first before it reacts with silicate ions. It explains why the Mg‐rich carbonatite has a lower dissolution rate in water glass.

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