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BACKGROUND The accurate determination of ionic phase rare earths in ion-adsorption rare earths is of great significance for the evaluation of rare earth ore bodies. Ionic phase rare earths are adsorbed on clay minerals in the form of hydroxyl or hydrated hydroxyls and can be exchanged and desorbed with strong electrolytes (Mg2+, NH4+, etc.) into solution. The former used ammonium sulfate as the leachate to achieve the desorption and extraction of rare earth ions in the ion phase, but the solution concentration, leaching process and other aspects of choice, leaching rates (60% to 90%) are different. There is no efficient and uniform leaching method conducive to the accurate determination of ionic phase rare earth elements. OBJECTIVES To establish a high-efficiency leaching process by ammonium sulfate solution and determine the accurate contents of ionic-phase rare earth elements. METHODS The leaching parameters (solid-to-liquid ratio, ammonium sulfate concentration, best sample weight, and soaking time) of rare-earth ions by ammonium sulfate were standardized through comparative experiments, which reduced the loss of ionic phase rare earth during leaching. The leaching rates were from 88% to 98%, and ICP-MS was used to accurately determine the ion phase rare earth component. RESULTS The detection limits are 0.05-5.11 ng/g, and the relative standard deviations (RSDs) are 1.80%-10.01% for volcanic rock, 1.06%-7.27% for metamorphic rock, and 1.72%-7.58% for sedimentary rock. CONCLUSIONS The analytical results of the collaborative laboratory verify the reliability and accuracy of the method. This method is easy to operate and has high analysis efficiency. It provides the base for the establishment of relevant industry standards and national standards.

BACKGROUND Os can be separated from the sample matrix by distillation, and the absorbing liquid can be introduced into ICP-MS directly, which is a key step of the molybdenite Re-Os isotopic age analysis. However, the Os signal intensity declines significantly after long time storage. According to the properties of OsO4, the possible causes may include:1) volatilization which reduces the Os content in the absorbing liquid, and 2) the reduction in which Os(Ⅷ) transforms to the low valence state without volatility and OsO4 in the gas state decreases. Although they can both reduce the Os being introduced into ICP-MS ultimately, the extent of their effect is not clear. OBJECTIVES To quantify the effects of absorbing liquid storage conditions such as duration, acidity and temperature on the Os signal intensity, to identify the cause of this decline and to find out the methods for its suppression. METHODS:The experiment consists of two parts:1) using the molybdenite Re-Os dating reference materials to construct a different absorbing liquid storage condition series, including duration, acidity and temperature, and measure their Os signal intensities in terms of 187Os/193Ir relative ratios. 2) sealing the residual absorbing liquid together with the spike and oxidizing agents within the Carius tube with sequent heating and distillation. The 187Os/190Os ratios were determined to calculate the Os content and the retention rate. RESULTS After storing, the Os signal intensities of absorbing liquids decline with time from 3.2% to 68.6%. The longer time, the lower acidity and the higher temperature for OsO4 absorbing liquid storage, the more obvious Os signal declines. After storing at room temperature for the same time, the Os retention rate of the low-acidity series is higher than that of the high-acidity series, but the former has a lower signal intensity than the latter. This indicates that both volatilization and reduction contribute to the decline of Os signal intensity and are the main factors. CONCLUSIONS Freezing to -18℃ can inhibit the volatilization of OsO4, whereas increasing the acidity (about 3.5 mol/L) can reduce OsO4 reduction. The combination of the two inhibits signal attenuation, and increases the flexibility and applicability of the distillation method.

Tumor recurrence and unfavorable bacterial biofilm formation on implants after bone tumor resection remain challenging in clinical settings. However, this dilemma also provides inspiration for the development of bioactive implants and a new route for the management of bone tumors through biofilm formation. Here, based on the characteristic that bacteria prefer to adhere to implants, 3D‐printing bioceramic scaffolds modified with probiotic biofilms are designed to augment antitumor immunity. In comparison with Akkermansia muciniphila, Lactobacillus rhamnosus GG (LGG) is demonstrated to more easily form biofilms on bioceramics and is selected to engineer etched bioceramics. The LGG biofilm subjected to pasteurization guarantees good biocompatibility and enhanced doxorubicin (Dox) loading. Furthermore, the LGG biofilm combined with Dox imparts the scaffolds with multiple properties of direct chemo‐killing for tumor cells and potent immune activation. The modified scaffolds efficiently inhibit bone tumor recurrence and bone metastasis in murine tumor model receives surgical resection. Moreover, based on 3D‐printing technology, the probiotic biofilm modified scaffolds with adjustable shapes are also demonstrated to repair shape‐specific bone defects after tumor elimination. Collectively, the multifunctional 3D‐printing scaffolds realize the integrated treatment of tumor elimination and bone repair, providing a promising strategy for clinical treatment of bone tumors. [ABSTRACT FROM AUTHOR]

Aiming at the shortcomings of the existing methods to detect the security flaws that have complex structures,a new analysis model and its application method was proposed.First,analysis models based on key information of code structures extracted from path subsets of characteristic element sets that are generated by source code element sets of code security flaws were constructed.Then the analysis model according to the statistical probability of each kind of IR statement was calculated,and the IR code group which matched the feature model was found.Finally,through the translating relation between binary codes and IR codes,various code security flaws of binary program were found out.The analysis models can be applied to both common single-process binary programs and binary parallel programs.Experimental results show that compared with the existing methods,the application of the analysis model can be more comprehensive and in-depth in detecting various types of complex binary code security flaws with higher accuracy.

Graphite has relatively high Re and Os contents and is an ideal mineral for Re-Os isotope dating. However, there are few studies on Re-Os dating of graphite. Particularly for the graphite which was formed by deformation of coal beds, the variation in Re-Os isotope system needs further study. The Lutang graphite deposit in Hunan is one of the typical cryptocrystalline graphite deposits in China. The ore-bodies are hosted in coals of the Permian Longtan Formation. In this study, the Re-Os isotopic compositions of the graphite samples from Lutang deposit and the raw coal samples from the peripheral area were analyzed by digesting sample in the Carius tube, direct distilling Os from the Carius tube, extracting Re by acetone and determining Re and Os isotopes by Negtive Thermal Ionization Mass Spectrometry. The results indicate that the Re and Os contents are 0.901-9.794 ng/g and 7.3-189.5 pg/g, respectively. The Re-Os isotope isochron age is 155.6±3.6 Ma, which is consistent with the zircon U-Pb age (153-157 Ma) of StageⅡ medium-grained biotite granite of the Qitianling pluton on the east side of the deposit. It also indicates that the coal seam of the Longtan Formation is subjected to 'baking' by the Qitianling pluton, inducing the hot contact metamorphism and changing the raw coal near the Qitianling pluton to graphite to form a graphite deposit. The comparison of Re and Os content and Os isotopic composition between the graphite, coal and Qitianlign pluton demonstrates that the Re and Os in the graphite are mainly derived from raw coal. According to the initial Os isotope ratio of 0.686±0.032, it can be concluded that minor Os with low 187Os/188Os value was absorbed by carbonaceous material during the intrusion of coal seam by the Qitianling pluton.

Volcanic rocks in the Xiemisitai Mountains, in Northwest Junggar were recently considered to form in the Silurian rather than the Devonian period. However, the characteristic and tectonic setting of Middle Silurian volcanic rocks in this area are poorly constrained. In this study, major and trace elements and Sr-Nd-Os isotopic composition analyses were synthetically conducted on the Middle Silurian basalt and basaltic andesite in northwest of the Xiemisitai Mountains, West Junggar. These volcanic samples are characterized by high MgO (5.15%-7.81%) with Mg of 56.0-60.7, low CaO (4.56%-5.09%) and FeOT/MgO (1.15-1.40), similar to those of high-Mg volcanic rocks. Basalts have εNd(t) of 2.65, (87Sr/86Sr)i of 0.70439, and (187Os/188Os)i of 0.4901. The slightly enriched isotopic signatures, high Th/Yb (2.2-2.7) and low Ba/La (17.4-33.4) indicate that they originated from depleted mantle metasomatized by melts from subducted sediments and suffered from crustal contamination. The volcanic rocks are calc-alkaline and exhibit arc-like geochemistry with the enrichment of light REE and large ion lithophile elements. It is suggested that these rocks were probably formed in a back-arc setting due to northward subduction of the Junggar Oceanic slab.

Chilling is a cost-effective and safe method of immobilising flies in "Drosophila" experiments. However, should condensation form on the plate, it would be fatal to the flies. Here we describe a modified cooling method using reusable commercial ice pack(s) (ca. 400 ml, 2-3 cm tall) rather than crushed ice. The ice pack is covered with a piece of filter paper which absorbs the condensed water formed on the cold surface, and the moistened filter paper does not wet the wings of flies inverted onto it. An ice pack (ca. 400 ml) takes effect in at least 1 h, and its height is shorter than the maximum specimen height of a dissecting microscope, so that flies can be checked while they remain on the cold surface. This method overcomes the disadvantages of the indigenous cooling anaesthetising approach and makes it practically feasible. We also describe an easy-to-make fly-transferring toolkit which will greatly facilitate fly transferral when it is combined with our chilling method. In our design, the flies were directed out of a vial by a blue pipette tip, which is inserted in a foam stopper and channelled down into another vial by a glass funnel inserted in another foam stopper which is escape-proof.