52 research outputs found

    Corrigendum to: The TianQin project: current progress on science and technology

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    In the originally published version, this manuscript included an error related to indicating the corresponding author within the author list. This has now been corrected online to reflect the fact that author Jun Luo is the corresponding author of the article

    Regulation of mesenchymal stem to transit amplifying cell transition in the continuously growing mouse incisor

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    Summary In adult tissues and organs with high turnover rates, the generation of transit-amplifying cell (TAC) populations from self-renewing stem cells drives cell replacement. The role of stem cells is to provide a renewable source of cells that give rise to TACs to provide the cell numbers that are necessary for cell differentiation. Regulation of the formation of TACs is thus fundamental to controlling cell replacement. Here, we analyze the properties of a population of mesenchymal TACs in the continuously growing mouse incisor to identify key components of the molecular regulation that drives proliferation. We show that the polycomb repressive complex 1 acts as a global regulator of the TAC phenotype by its direct action on the expression of key cell-cycle regulatory genes and by regulating Wnt/β-catenin-signaling activity. We also identify an essential requirement for TACs in maintaining mesenchymal stem cells, which is indicative of a positive feedback mechanism

    Late Palaeozoic igneous rocks of the Great Xing’an Range, NE China: the Tayuan example

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    <p>The Tayuan plutons located at the boundary of the Erguna and Xing’an blocks expose a coexisting mafic–felsic association that is made of monzogranite and gabbro-monzodiorite as well as subordinate quartz monzonite. LA–ICP–MS U–Pb zircon dating revealed a synchronous emplacement of the monzogranite (314–317 Ma), gabbro (308–315 Ma), and quartz monzonite (310 ± 3 Ma). The majority of these intrusions are characterized by an enrichment in light rare earth elements relative to heavy rare earth elements and a depletion of high strength field elements (e.g. Nb, Ta, Ti). Zircons from the gabbro and monzogranite have ε<sub>Hf</sub>(t) values of 1.1–9.6 and −3.0–3.3, respectively. Geochemical data show that the gabbro-monzodiorite may have been generated by the melting of a fluid-metasomatized lithospheric mantle, while the monzogranite may have been formed by a partial melting of the Mesoproterozoic crust. The quartz monzonite has similar whole-rock geochemical and Hf isotopic compositions to those of the gabbros and could have been produced from the same mantle source as that from which the gabbros were extracted. The Tayuan plutonic rocks have high contents of K<sub>2</sub>O and total alkalis and show a northwestward polarity like that of the continental margin plutonic rocks along the Hegenshan–Heihe suture zone. Combined with data from published studies, our data indicate that the Tayuan intrusive rocks were generated by the northwestward subduction of the Hegenshan–Heihe Oceanic plate.</p

    Performance of Different Varieties of Spring Field Pea (<i>Pisum sativum</i> L.) under Irrigated and Rainfed Environments in North China

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    Field pea (Pisum sativum L.) is one of the most important pulse crops, and is widely grown in North China. To exploit potential pea varieties suitable for growing in spring planting areas, a set National Regional Trials of Spring Pea Genotype was carried out under irrigated and rainfed environments across seven locations. Grain yield and agronomic traits of fourteen pea cultivars were evaluated. Analysis of variance indicated that the effect of genotype, environments and genotypes × environments interaction was significant (p < 0.01). Results of GGE biplot analysis showed that the first and second principal components accounted for 77.5% and 14.5%, respectively. Genotypes accounted for just 14.7% of the variation in seed yield, while environments accounted for 39.9%, and genotypes × environments interaction accounted for 45.5% of the variation. Investigating the polygon view led to the identification of five superior genotypes and five productivity environments. Superior genotypes and key environments for grain yield were determined using a general linear model. The significant genotypes × environments interaction effects indicated the inconsistent performance of genotypes across the tested environments. Among the tested genotypes, significant differences were observed for grain yield and yield-related traits. The semi-leafless pea variety Longwan 10 was observed the highest yield (3308 kg/ha) over seven locations. Dingwan 12, Dingwan 13, Tongwan 5, Kewan 7 showed higher, stable grain yield than the overall mean of genotypes and check variety Zhongwan 6. The most representative and productivity regions for grain yield of field pea were Yondeng, Qitai, Liaoyang, Dingxi and Tangshan. These findings represent a comprehensive analysis of yield and stability of spring pea varieties and growing locations, which may be useful for national and international pea improvement programs

    The Involvement of RhoA and Wnt-5a in the Tumorigenesis and Progression of Ovarian Epithelial Carcinoma

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    Background: Ras homolog gene family member A (RhoA) is involved in Wnt-5a–induced migration of gastric and breast cancer cells. We investigated the roles of RhoA and Wnt-5a in ovarian carcinoma. Methods: RhoA and Wnt-5a mRNA and protein expression in normal fallopian tube epithelium, benign tumors, primary ovarian carcinomas, and metastatic omentum were quantified. RhoA or Wnt-5a was knocked down in OVCAR3 ovarian carcinoma cells using siRNAs and cell phenotype and expression of relevant molecules were assayed. Results: RhoA and Wnt-5a mRNA and protein expression were found to be significantly higher in metastatic omentum than in ovarian carcinomas, benign tumors, and normal fallopian tube epithelium (p &lt; 0.05), and positively associated with differentiation and FIGO staging (stage I/II vs. stage III/IV) in ovarian carcinoma (p &lt; 0.05). RhoA and Wnt-5a expression were positively correlated in ovarian carcinoma (p = 0.001, R2 = 0.1669). RhoA or Wnt-5a knockdown downregulated RhoA and Wnt-5a expression; reduced cell proliferation; promoted G1 arrest and apoptosis; suppressed lamellipodia formation, cell migration, and invasion; and reduced PI3K, Akt, p70S6k, Bcl-xL, survivin, and VEGF mRNA or protein expression. Conclusions: This is the first demonstration that RhoA and Wnt-5a are associated with ovarian carcinogenesis and apoptosis inhibition; there might be positive correlation between RhoA and Wnt-5a expression. RhoA is a potential tumorigenesis, differentiation, and progression biomarker in ovarian carcinoma

    Petrogenesis of Ore-Hosting Diorite in the Zaorendao Gold Deposit at the Tongren-Xiahe-Hezuo Polymetallic District, West Qinling, China

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    The newly discovered Zaorendao gold deposit is in the Tongren-Xiahe-Hezuo polymetallic district in the westernmost West Qinling orogenic belt. The estimated pre-mining resource is approximately 13.6 t of Au at an average grade of 3.02 g/t. Mineralization is predominantly controlled by NW-trending and EW-trending faults within diorite intrusions and surrounding sedimentary rocks. In the present study, in situ zircon U&#8315;Pb geochronology and Lu&#8315;Hf isotopic analyses of the ore-hosting diorite at Zaorendao were measured using LA-ICP-MS. The data suggest that the diorite was emplaced at ca. 246.5 &#177; 1.9 Ma. The large variation of zircon Hf isotopic composition (ɛHf(t) values ranging from &#8722;12.0 to &#8722;1.8) indicates a two-stage model age (TDM2) that ranges from 1.4 Ga to 2.0 Ga. Such Lu&#8315;Hf isotopic compositions indicate that the diorite was dominantly derived from a Paleo- to Meso-Proterozoic continental crust. The wide range of &#949;Hf(t) and the presence of inherited zircon can be interpreted to suggest the mixing of Paleo- to Meso-Proterozoic continental crust with a mantle component. Combining such characteristics with the geochemistry of coeval rocks that are associated with the diorite, we therefore proposed that the gold-hosting Triassic diorite in the Zaorendao gold deposit formed in an active continental margin that was associated with the northward subduction of the paleo-Tethyan ocean

    Nature and origin of Triassic igneous activity in the Western Qinling Orogen: the Wenquan composite pluton example

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    <p>The Western Qinling has been acknowledged to witness superimposed orogeny including north subduction of Paleotethys ocean and collision between North China and South China blocks; however, the precise timing constraints on transition of tectonic regime are remaining enigmatic. The Wenquan composite batholith comprising five phases and mafic enclaves is an ideal example to unlock this puzzle. The host granitoids are felsic, metaluminous to peraluminous, and high-K calc-alkaline to shoshonitic suite with I-type affinity. The mafic enclaves, however, are intermediate, and high-K calc-alkaline to shoshonitic. Zircon ages of multiple phases indicate an episodic growth lasting nearly 30 million years ranging from 238, 228, 218 to 208 Ma, consistent to Triassic igneous activity recording a transition regime from a subduction setting to a syn-collision setting and a post-collision setting in Western Qinling. Lead isotopes of whole-rock and K-feldspar at Wenquan and Lu-Hf isotopes of zircons separated from biotite monzogranite porphyry, porphyritic monzogranite, monzogranite porphyry, and hosted mafic enclaves suggest that the heat and the hot mafic melt initiated by the break-off of the northward subducting South China block lithosphere triggered partial melting of the Mesoproterozoic subcontinental lithospheric mantle to produce mafic magmas, and the underplated mafic magmas caused partial melting of the shallow subducted Mesoproterozoic lower crust generating granitic magmas at Wenquan. Combined our field observations and petrology study with a holistic review on previous geochronological and geochemical data of Triassic granitoids throughout the Western Qinling, we in this contribution proposed that the Triassic igneous activity in the Western Qinling corresponding to superimposed orogeny evolved from the northward subduction of Palaeotethys ocean (250–235 Ma) through syn-collision (228–215 Ma) to post-collision (215–185 Ma) between the North China and South China blocks.</p

    Geochronological and Geochemical Constraints on the Formation of the Giant Zaozigou Au-Sb Deposit, West Qinling, China

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    The Zaozigou Au-Sb deposit has been controversial in its genesis and remains one of the most difficult ore systems to fully understand in West Qinling. The mineralization shows a broad spatial association with Triassic dikes and sills, which were previously thought to be genetically related to mineralization. Our U-Pb zircon dating in this contribution indicates that the ore-hosting porphyritic dacites were formed at 246.1 &plusmn; 5.2 Ma and 248.1 &plusmn; 3.8 Ma. The magmatic zircons yield &epsilon;Hf(t) values ranging from &minus;12.5 to &minus;8.9, with corresponding two-stage model ages of 2.08 to 1.83 Ga. The magma therefore could be derived from partial melting of Paleoproterozoic crustal materials. The ore-hosting porphyritic dacites have low oxygen fugacity, with &Delta;FMQ ranging from &minus;4.61 to &minus;2.56, indicating that magmas could have been sulfide-saturated during evolution in deep chambers and precluding the possibility that metals were released from the melt. Zaozigou exhibits characteristics widespread volcanics, massive sulfide mineralization, rare reduced mineral assemblage and discrete alteration zones which are not typical of reduced intrusion-related or porphyry gold systems. We propose that the spatially-related Triassic porphyritic dacite and dike swarm is not genetically related to the ore formation of Zaozigou Au-Sb deposit
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