Biocompatible magnetite nanocrystals (see Figure) are prepared by thermal decomposition of ferric triacetylacetonate in 2‐pyrrolidone in the presence of monocarboxyl‐terminated poly(ethylene glycol) ...(MPEG‐COOH). The results reveal that MPEG is covalently bound to the nanocrystal surface by COOH groups. Magnetic resonance imaging (MRI) experiments indicate that the coated nanocrystals are potential MRI contrast agents due to their excellent water solubility and biocompatibility.
High-Entropy Alloys in Hexagonal Close-Packed Structure Gao, M. C.; Zhang, B.; Guo, S. M. ...
Metallurgical and materials transactions. A, Physical metallurgy and materials science,
07/2016, Volume:
47, Issue:
7
Journal Article
Peer reviewed
Open access
The microstructures and properties of high-entropy alloys (HEAs) based on the face-centered cubic and body-centered cubic structures have been studied extensively in the literature, but reports on ...HEAs in the hexagonal close-packed (HCP) structure are very limited. Using an efficient strategy in combining phase diagram inspection, CALPHAD modeling, and
ab initio
molecular dynamics simulations, a variety of new compositions are suggested that may hold great potentials in forming single-phase HCP HEAs that comprise rare earth elements and transition metals, respectively. Experimental verification was carried out on CoFeReRu and CoReRuV using X-ray diffraction, scanning electron microscopy, and energy dispersion spectroscopy.
Tea is the world's most popular non-alcoholic beverage. China and India are known to be the largest tea producing countries and recognized as the centers for the domestication of the tea plant ...(Camellia sinensis (L.) O. Kuntze). However, molecular studies on the origin, domestication and relationships of the main teas, China type, Assam type and Cambod type are lacking.
Twenty-three nuclear microsatellite markers were used to investigate the genetic diversity, relatedness, and domestication history of cultivated tea in both China and India. Based on a total of 392 samples, high levels of genetic diversity were observed for all tea types in both countries. The cultivars clustered into three distinct genetic groups (i.e. China tea, Chinese Assam tea and Indian Assam tea) based on STRUCTURE, PCoA and UPGMA analyses with significant pairwise genetic differentiation, corresponding well with their geographical distribution. A high proportion (30%) of the studied tea samples were shown to possess genetic admixtures of different tea types suggesting a hybrid origin for these samples, including the Cambod type.
We demonstrate that Chinese Assam tea is a distinct genetic lineage from Indian Assam tea, and that China tea sampled from India was likely introduced from China directly. Our results further indicate that China type tea, Chinese Assam type tea and Indian Assam type tea are likely the result of three independent domestication events from three separate regions across China and India. Our findings have important implications for the conservation of genetic stocks, as well as future breeding programs.
We present X-ray timing results of the new black hole candidate MAXI J1535−571 during its 2017 outburst from Hard X-ray Modulation Telescope (Insight-HXMT) observations taken from 2017 September 6 to ...23. Following the definitions given by Belloni, we find that the source exhibits transitions from the low/hard state to the hard intermediate state, and eventually to the soft intermediate state. Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of Insight-HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV, which has rarely been explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lag) and strongly correlated with the centroid frequency. Assuming a geometrical origin of type-C QPOs, the source is consistent with being a high-inclination system.
Peritoneal metastasis is the common route of metastasis in gastric cancer and is a major cause of death in advanced gastric cancer. Early intervention with comprehensive treatment can effectively ...improve the prognosis of some patients with peritoneal metastasis. However, early peritoneal metastasis in gastric cancer is predominantly micro-metastasis, which cannot be effectively evaluated by imaging studies. Moreover, the detection of disseminated cancer cells in peritoneal lavage suffers from a low detection rate and significant heterogeneity. In recent years, the development and application of new liquid biopsy technologies such as circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have provided new means to assess potential peritoneal metastasis at the cellular and molecular levels, gradually becoming research hotspots in this field. This review will summarize the relevant progress of liquid biopsy in peritoneal metastasis, which holds significant importance for improving the prognosis of gast
To explore the effect of lncRNA ADPGK-AS1 on the proliferation and apoptosis of retinoblastoma cells and its possible mechanism.
The tumor tissues of 31 patients with retinoblastoma admitted to Henan ...Provincial Eye Hospital from February to June 2020 and their corresponding normal tissues adjacent to the cancer were collected. The expression levels of lncRNA ADPGK-AS1 and miR-200b-5p in retinoblastoma tissues and normal adjacent tissues were detected by real-time fluorescence quantitative polymerase chain reaction (qRT-PCR). Human retinal epithelial cell ARPE-19, human retinoblastoma cell Y-79 and WERI-Rb-1 were cultured
. The expression levels of lncRNA ADPGK-AS1 and miR-200b-5p were detected by qRT-PCR. Y-79 cells were randomly divided into si-con group, si-lncRNA ADPGK-AS1 group, miR con group, miR-200b-5p group, si-lncRNA ADPGK-AS1+ anti-miR con group, and si-lncRNA ADPGK-AS1+ anti-miR-200b-5p group. The proliferation, cloning and apoptosis of cells in each group were detected by tetramethylazol blue meth
Dioscin, one natural product, has various pharmacological actions. However, its effects on methotrexate (MTX)-induced hepatorenal damages still remain unknown. In the present study, the data ...manifested that dioscin restored the viabilities of L-02 and NRK-52E cells, reduced ALT, AST, Cr, BUN levels, and ameliorated histopathological changes of liver and kidney. Besides, dioscin decreased ROS levels in cells, and adjusted SOD, MDA, GSH and GSH-Px levels in rats. Dioscin reduced the expression levels of miR-145–5p which directly targeted Sirt5, and then regulated the expression levels of SOD1, Nrf2, Gst, Keap1, HO-1, GCLC and NQO1. MiR-145–5p mimic in cells deteriorated ROS levels and decreased Sirt5 expression to accentuate oxidative stress by regulating the expression levels of SOD1, Nrf2, Keap1, which were all reversed by dioscin. Moreover, MTX-induced hepatorenal damage were worsened in mice by Sirt5 siRNA or miR-145–5p agomir, which were also alleviated by dioscin. Dioscin relieved MTX-induced hepatorenal damages through regulating miR-145-5p-medicated oxidative stress, which should be considered as one effective drug to treat the disorder in future.
Proposed signaling mechanism of dioscin on restoring MTX-induced liver and kidney damages via regulating miR-145-5p-mediated oxidative stress. Dioscin up-regulated Sirt5 level by down-regulating miR-145–5p level to adjust the expression levels of Nrf2, HO-1, GCLC, NQO1, Gst, SOD1 and Keap1. Dioscin protected hepatorenal damages caused by MTX via regulating miR-145-5p-mediated oxidative stress. Display omitted
•Dioscin significantly relieved MTX-induced hepatorenal damages in vitro and in vivo.•MTX caused oxidative damages to the liver and kidney in vitro and in vivo.•miR-145–5p directly targeted Sirt5 to adjust oxidative stress.•Dioscin reduced the expression levels of miR-145–5p and suppressed w miR-145-5p-medicated oxidative stress.
This paper presents the first results of the measurements of trace gases and aerosols at three surface sites in and outside Beijing before and during the 2008 Olympics. The official air pollution ...index near the Olympic Stadium and the data from our nearby site revealed an obvious association between air quality and meteorology and different responses of secondary and primary pollutants to the control measures. Ambient concentrations of vehicle-related nitrogen oxides (NOx) and volatile organic compounds (VOCs) at an urban site dropped by 25% and 20–45% in the first two weeks after full control was put in place, but the levels of ozone, sulfate and nitrate in PM2.5 increased by 16%, 64%, 37%, respectively, compared to the period prior to the full control; wind data and back trajectories indicated the contribution of regional pollution from the North China Plain. Air quality (for both primary and secondary pollutants) improved significantly during the Games, which were also associated with the changes in weather conditions (prolonged rainfall, decreased temperature, and more frequent air masses from clean regions). A comparison of the ozone data at three sites on eight ozone-pollution days, when the air masses were from the southeast-south-southwest sector, showed that regional pollution sources contributed >34–88% to the peak ozone concentrations at the urban site in Beijing. Regional sources also contributed significantly to the CO concentrations in urban Beijing. Ozone production efficiencies at two sites were low (~3 ppbv/ppbv), indicating that ozone formation was being controlled by VOCs. Compared with data collected in 2005 at a downwind site, the concentrations of ozone, sulfur dioxide (SO2), total sulfur (SO2+PM2.5 sulfate), carbon monoxide (CO), reactive aromatics (toluene and xylenes) sharply decreased (by 8–64%) in 2008, but no significant changes were observed for the concentrations of PM2.5, fine sulfate, total odd reactive nitrogen (NOy), and longer lived alkanes and benzene. We suggest that these results indicate the success of the government's efforts in reducing emissions of SO2, CO, and VOCs in Beijing, but increased regional emissions during 2005–2008. More stringent control of regional emissions will be needed for significant reductions of ozone and fine particulate pollution in Beijing.
Nucleation of shear bands is of critical importance in the deformation behaviors of metallic glasses, but the detailed examination of nucleation kinetics and the correlation with the structure and ...relaxation kinetics has been few. Here, based upon instrumented nanoindentation with spherical indenter and a great deal of the observed first pop-in events, one unique trimodal distribution of shear band nucleation events in a Gd-based metallic glass was reported. Four different loading rates were employed to study the evolution of the nucleation distribution with external loading. In the analyses of nucleation kinetics, the site density, nucleation rate and activation barrier for three nucleation events were obtained based on the cooperative deformation model, which clearly display the trimodal character. The discovery of a trimodal shear band nucleation distribution provides new insights for understanding the relationship between the heterogeneous structure, relaxation kinetics and deformation mechanism and opportunities for controlling the ductility of amorphous alloys.
•An effective strategy by nanoindentation reveal the multiple distribution of shear band nucleation.•A unique trimodal distribution of shear band nucleation sites in Gd-based MG for the first time.•The diagram of first pop-in load with loading rates for three nucleation sites were plotted.•The nucleation sits density, nucleation rate and activation barrier for three nucleation sites were determined.•The types of shear band nucleation sites are related to the types of characteristic relaxation behavior.
A state of matter in which molecules show a long-range orientational order and no positional order is called a nematic liquid crystal. The best known and most widely used (for example, in modern ...displays) is the uniaxial nematic, with the rod-like molecules aligned along a single axis, called the director. When the molecules are chiral, the director twists in space, drawing a right-angle helicoid and remaining perpendicular to the helix axis; the structure is called a chiral nematic. Here using transmission electron and optical microscopy, we experimentally demonstrate a new nematic order, formed by achiral molecules, in which the director follows an oblique helicoid, maintaining a constant oblique angle with the helix axis and experiencing twist and bend. The oblique helicoids have a nanoscale pitch. The new twist-bend nematic represents a structural link between the uniaxial nematic (no tilt) and a chiral nematic (helicoids with right-angle tilt).
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