57 research outputs found

    BRI1 EMS SUPPRESSOR1 genes regulate abiotic stress and anther development in wheat (Triticum aestivum L.)

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    BRI1 EMS SUPPRESSOR1 (BES1) family members are crucial downstream regulators that positively mediate brassinosteroid signaling, playing vital roles in the regulation of plant stress responses and anther development in Arabidopsis. Importantly, the expression profiles of wheat (Triticum aestivum L.) BES1 genes have not been analyzed comprehensively and systematically in response to abiotic stress or during anther development. In this study, we identified 23 BES1-like genes in common wheat, which were unevenly distributed on 17 out of 21 wheat chromosomes. Phylogenetic analysis clustered the BES1 genes into four major clades; moreover, TaBES1-3A2, TaBES1-3B2 and TaBES1-3D2 belonged to the same clade as Arabidopsis BES1/BZR1 HOMOLOG3 (BEH3) and BEH4, which participate in anther development. The expression levels of 23 wheat BES1 genes were assessed using real-time quantitative PCR under various abiotic stress conditions (drought, salt, heat, and cold), and we found that most TaBES1-like genes were downregulated under abiotic stress, particularly during drought stress. We therefore used drought-tolerant and drought-sensitive wheat cultivars to explore TaBES1 expression patterns under drought stress. TaBES1-3B2 and TaBES1-3D2 expression was high in drought-tolerant cultivars but substantially repressed in drought-sensitive cultivars, while TaBES1-6D presented an opposite pattern. Among genes preferentially expressed in anthers, TaBES1-3B2 and TaBES1-3D2 expression was substantially downregulated in thermosensitive genic male-sterile wheat lines compared to common wheat cultivar under sterile conditions, while we detected no obvious differences under fertile conditions. This result suggests that TaBES1-3B2 and TaBES1-3D2 might not only play roles in regulating drought tolerance, but also participate in low temperature-induced male sterility

    Artificial intelligence : A powerful paradigm for scientific research

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    Y Artificial intelligence (AI) coupled with promising machine learning (ML) techniques well known from computer science is broadly affecting many aspects of various fields including science and technology, industry, and even our day-to-day life. The ML techniques have been developed to analyze high-throughput data with a view to obtaining useful insights, categorizing, predicting, and making evidence-based decisions in novel ways, which will promote the growth of novel applications and fuel the sustainable booming of AI. This paper undertakes a comprehensive survey on the development and application of AI in different aspects of fundamental sciences, including information science, mathematics, medical science, materials science, geoscience, life science, physics, and chemistry. The challenges that each discipline of science meets, and the potentials of AI techniques to handle these challenges, are discussed in detail. Moreover, we shed light on new research trends entailing the integration of AI into each scientific discipline. The aim of this paper is to provide a broad research guideline on fundamental sciences with potential infusion of AI, to help motivate researchers to deeply understand the state-of-the-art applications of AI-based fundamental sciences, and thereby to help promote the continuous development of these fundamental sciences.Peer reviewe

    Prognostic value of EZH2 in non-small-cell lung cancers : a meta-analysis and bioinformatics analysis

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    Background. The prognosis of non-small-cell lung cancer (NSCLC) has not been significantly improved. In the past several years, research on epigenetics is in full swing. There is a focus on the gene EZH2; however, its role as a predictor of the prognosis of NSCLC is in the debate. Objective. To clarify if the expression level of EZH2 can influence the prognosis of NSCLC and explain its prognostic value. Methods. We have systematically searched PubMed, Web of Science, and Cochrane library, screened relevant articles, and conducted a meta-analysis on the expression level of EZH2 in NSCLC. We collected the hazard ratio (HR) and the 95% confidence interval (CI) and used STATA 12.0 to calculate the combined result of EZH2 overall survival. In addition, we conducted subgroup analyses, a sensitivity analysis, and a funnel plot to test the reliability of the results. We further validated these meta-analysis results using the Kaplan-Meier plotter database and The Cancer Genome Atlas (TCGA) database. In addition, we have investigated the correlation between EZH2 expression and EGFR expression, KRAS expression, BRAF expression, and smoking in TCGA database to further explore the mechanism behind the influence of high EZH2 expression on lung cancer prognosis. Results. 13 studies including 2180 participants were included in the meta-analysis. We found that high expression of EZH2 indicates a poor prognosis of NSCLC (HR = 1:65 and 95% CI 1.16-2.35; p ≤ 0:001). Subgroup analyses showed high heterogeneity in stages I-IV (I2 = 85:1% and p ≤ 0:001) and stages I-III (I2 = 66:9% and p = 0:029) but not in stage I (I2 = 0:00% and p = 0:589). In the Kaplan-Meier plotter database, there was a high expression in 963 cases and low expression in 964 cases (HR = 1:31 and 95% CI 1.15-1.48; p < 0:05). Further analysis found that the high expression of EZH2 was statistically significant in lung adenocarcinoma (HR = 1:27and 95% CI 1.01−1.6; p = 0:045), but not in lung squamous cell carcinoma (HR = 1:03 and 95% CI 0.81−1.3; p = 0:820). The results of the TCGA database showed that the expression of EZH2 in normal tissues was lower than that in lung cancer tissues (p < 0:05). Smoking was associated with high expression of EZH2 (p < 0:001). EZH2 was also highly expressed in lung cancers with positive KRAS expression, and the correlation was positive in lung adenocarcinoma (r = 0:3129 and p < 0:001). The correlation was also positive in lung squamous cell carcinoma (r = 0:3567 and p < 0:001). EZH2 expression was positively correlated with BRAF expression (r = 0:2397 and p < 0:001), especially in lung squamous cell carcinoma (r = 0:3662 and p < 0:001). In lung squamous cell carcinoma, a positive yet weak correlation was observed between EZH2 expression and EGFR expression (r = 0:1122 and p < 0:001). Conclusions. The high expression of EZH2 indicates a poor prognosis of NSCLC, which may be related to tumor stage or cancer type. EZH2 may be an independent prognostic factor for NSCLC. EZH2 high expression or its synergistic action with KRAS and BRAF mutations affects the prognosis of non-small-cell lung cancer

    Iron Isotope Systematics of the Panzhihua Mafic Layered Intrusion Associated With Giant Fe-Ti Oxide Deposit in the Emeishan Large Igneous Province, SW China

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    In order to investigate how Fe was enriched from parental high-Ti basaltic magma to form the stratigraphically thick Fe-Ti oxide ore at the bottom layers, we present a systematic study for Fe isotopic compositions of whole rocks and mineral separates (clinopyroxene, magnetite, and ilmenite) throughout the Panzhihua intrusion. Whole rock Fe-56 ranges from 00.02 to 0.150.04, consistent with the range of clinopyroxene (0.01 +/- 0.02 parts per thousand to 0.16 +/- 0.05 parts per thousand). On the contrary, magnetite (Mt) separates have Fe-56 ranging from 0.17 +/- 0.05 parts per thousand to 0.62 +/- 0.02 parts per thousand, showing a strikingly complementary trend with coexisting ilmenite (Ilm) separates (-0.52 +/- 0.03 parts per thousand to -0.09 +/- 0.02 parts per thousand) along the profile. The calculated bulk Fe-56 of Fe-Ti oxides (Mt+Ilm), however, has a small range from 0.01 parts per thousand to 0.16 parts per thousand, identical to those for clinopyroxene separates and whole rocks. The uniform Fe-56 of clinopyroxene may have resulted from the small Fe isotope fractionation between clinopyroxene and parental magma in early-stage magma differentiation before substantial crystallization of Fe-Ti oxides. The complementary trends of Fe-56 for Mt and Ilm along the profile and the uniform bulk Fe-56 of Fe-Ti oxides are better interpreted as in situ crystallization of Fe-Ti oxides from the interstitial liquid. Our Fe isotopic data and petrographic observations indicate that the thick Fe-Ti oxide ore layers in the lower zone of the Panzhihua intrusion may be attributed to in situ crystallization of Mt and Ilm from the interstitial, immiscible Fe-rich melt in the lower part of the magma chamber

    Permeability of Concrete and Correlation with Microstructure Parameters Determined by 1H NMR

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    Water and gas permeability coefficients of concrete with different water-binder (w/b) ratios and admixtures were measured by a self-designed test device based on the steady-state flow method for liquid and the method of differential pressure in stability for gas, respectively. In addition, the micropore structure of concrete was determined by 1H nuclear magnetic resonance (NMR). Results indicated that there are good correlations between water and gas permeability of concrete with different w/b ratios, with correlation coefficient greater than 0.90. Better correlations between water permeability and segmental contributive porosity ranged from 10 to 100 nm and 100 to 1000 nm can be identified, but the gas permeability is more relevant to the segmental contributive porosity ranging from 100 to 1000 nm. Moreover, the correlation between water permeability and contributive porosity for each pore diameter is always better than that of gas permeability. The influence of admixtures on the relationship between permeability and pore size distribution of concrete is significant. Moreover, water permeability coefficient is one or two orders of magnitude lower than the gas permeability coefficient

    Iron isotopic composition of supra-subduction zone ophiolitic peridotite from northern Tibet

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    We present high-precision iron isotope data for harzburgites and constituting minerals from the Yushigou suprasubduction zone ophiolite in the North Qilian orogen of northern Tibet to provide insights into iron isotope behavior in subduction zones. The Yushigou harzburgites represent typical melting residues of silica-enriched forearc mantle wedge with significant melt extraction and minimal melt percolation. The delta Fe-56 ranges from -0.096% to 0.110% in olivine, from -0.111% to 0.105% in orthopyroxene and from -0.141% to 0.054% in spinel. Coexisting minerals fall on a line with a slope of 1 in the delta-delta plot, indicating iron isotope equilibrium between mineral pairs. Iron isotopic fractionation between olivine and orthopyroxene is minor, which is consistent with theoretical predictions and previous observations. Good iron isotopic equilibrium between olivine and orthopyroxene is a further indicator that silica enrichment in arc peridotites is inherited from their mantle source. In contrast, significantly negative iron isotopic fractionation between spinel and olivine contradicts with most previous constraints, which may be ascribed to Cr substitution in spinel. Bulk rock harzburgites have delta Fe-56 ranging from -0.097% to 0.076%, the average of which (0.002 +/- 0.020%) is similar to average delta Fe-56 determined for abyssal peridotites. Based on this inference, the lower delta Fe-56 of arc magmas than MORB should be due to smaller discrepancy in Fe3+/RFe between arc magmas and arc peridotites when compared with MORB and abyssal peridotites. Our modelling demonstrates that this can be achieved if arc magmas are produced by redox-buffered melting of silica-enriched mantle wedge while MORB are produced by redox-unbuffered melting of the depleted mantle. (C) 2019 Elsevier Ltd. All rights reserved

    Calcium Isotopic Compositions of Normal Mid-Ocean Ridge Basalts From the Southern Juan de Fuca Ridge

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    Mantle peridotites show that Ca is isotopically heterogeneous in Earth's mantle, but the mechanism for such heterogeneity remains obscure. To investigate the effect of partial melting on Ca isotopic fractionation and the mechanism for Ca isotopic heterogeneity in the mantle, we report high-precision Ca isotopic compositions of the normal Mid-Ocean Ridge Basalts (N-MORB) from the southern Juan de Fuca Ridge. Ca-44/40 of these N-MORB samples display a small variation ranging from 0.750.05 to 0.860.03 (relative to NIST SRM 915a, a standard reference material produced by the National Institute of Standards and Technology), which are slightly lower than the estimated Upper Mantle value of 1.050.04 parts per thousand and the Bulk Silicate Earth (BSE) value of 0.94 +/- 0.05 parts per thousand. This phenomenon cannot be explained by fractional crystallization, because olivine and orthopyroxene fractional crystallization has limited influence on Ca-44/40 of N-MORB due to their low CaO contents, while plagioclase fractional crystallization cannot lead to light Ca isotopic compositions of the residue magma. Instead, the lower Ca-44/40 of N-MORB samples compared to their mantle source is most likely caused by partial melting. The offset in Ca-44/40 between N-MORB and BSE indicates that at least 0.1-0.2 parts per thousand fractionation would occur during partial melting and light Ca isotopes are preferred to be enriched in magma melt, which is in accordance with the fact that Ca-44/40 of melt-depleted peridotites are higher than fertile peridotites in literature. Therefore, partial melting is an important process that can decrease Ca-44/40 in basalts and induce Ca isotopic heterogeneity in Earth's mantle

    A "peak cut" procedure of column separation for calcium isotope measurement using the double spike technique and thermal ionization mass spectrometry (TIMS)

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    Full recovery from column separation and matrix effects are the two factors that need to be considered for the high-precision analysis of stable Ca isotopes, but generally they are difficult to balance. In many cases, to get a pure Ca fraction, the interference of the matrix elements is reduced at the cost of discarding a fraction of Ca overlapping with other elements (e.g. Sr and K). However, quantitative evaluation using this approach is challenging but greatly needed. Our study investigates the influence of low Ca recovery on delta Ca-44/40 using thermal ionization mass spectrometry (TIMS) with the double spike technique. delta Ca-44/40 of IAPSO seawater, ML3B-G and BHVO-2 in different Ca subcuts (e.g. 0-20, 20-40, 40-60, 6080 and 80-100%), display limited variation after iterative correction by Ca-42-Ca-43 double spike with the exponential law. Notably, delta Ca-44/40 of each Ca subcut with similar to 20% recovery is consistent with that of the Ca cut with full recovery, within a margin of error. Our results indicate that Ca-42-Ca-43 double spike technique can simultaneously correct Ca isotopic fractionation, occurring during column separation, and TIMS determination, because both follow the exponential fractionation law well. Therefore, a "peak cut" procedure of column separation for Ca isotope measurement using the double spike technique on TIMS is proposed. Briefly, we can mix the double spike with the sample solution well before column separation, then collect the peak of the Ca cut and abandon both sides of the Ca eluate that may overlap with other elements. This procedure would eliminate matrix effects efficiently, especially for samples with low CaO contents which typically must be passed through the column twice (e.g. peridotite and dunite)
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