Scavenging and release of REE and HFSE by Na-metasomatism in magmatic-hydrothermal systems.

Exploitable or potentially exploitable deposits of critical metals, such as rare-earth (REE) and high-field-strength elements (HFSE), are commonly associated with alkaline or peralkaline igneous rocks. However, the origin, transport and concentration of these metals in peralkaline systems remains poorly understood. This study presents the results of a mineralogical and geochemical investigation of the Na-metasomatism of alkali amphiboles and clinopyroxenes from a barren peralkaline granite pluton in NE China, to assess the remobilization and redistribution of REE and HFSE during magmatic-hydrothermal evolution. Alkali amphiboles and aegirine-augites from the peralkaline granites show evolutionary trends from sodic-calcic to sodic compositions, with increasing REE and HFSE concentrations as a function of increasing Na-index [Na#, defined as molar Na/(Na+Ca) ratios]. The Na-amphiboles (i.e., arfvedsonite) and aegirine-augites can be subsequently altered, or breakdown, to form hydrothermal aegirine during late- or post-magmatic alteration. Representative compositions analyzed by in-situ LA-ICPMS show that the primary aegirine-augites have high and variable REE (2194-3627 ppm) and HFSE (4194-16,862 ppm) contents, suggesting that these critical metals can be scavenged by alkali amphiboles and aegirine-augites. Compared to the primary aegirine-augites, the presentative early replacement aegirine (Aeg-I, Na# = 0.91-0.94) has notably lower REE (1484-1972) and HFSE (4351-5621) contents. In contrast, the late hydrothermal aegirine (Aeg-II, Na# = 0.92-0.96) has significantly lower REE (317-456 ppm) and HFSE (6.44-72.2 ppm) contents. Given that the increasing Na# from aegirine-augites to hydrothermal aegirines likely resulted from Na-metasomatism, a scavenging-release model can explain the remobilization of REE and HFSE in peralkaline granitic systems. The scavenging and release of REE and HFSE by Na-metasomatism provides key insights into the genesis of globally significant REE and HFSE deposits. The high Na-index of the hydrothermal aegirine might be useful as a geochemical indicator in the exploration for these critical-metals.

[Eucommia ulmoides Oliv polysaccharide reduces the injury of IL-1ß-induced chondrocyte by inhibiting NF-κB pathway].

OBJECTIVE: To investigate the effects of Eucommia ulmoides Oliv polysaccharide on the injury of interleukin-1ß(IL-1ß)-induced chondrocyte and its possible mechanism. METHODS: ATDC5 was treated with 10 µg/ml IL-1ß to establish osteoarthritis chondrocyte inflammation model, mouse chondrocyte ATDC5 were cultured in vitro and randomly divided into blank group, model group, model+Eucommia ulmoides Oliv polysaccharide low concentration group, model+Eucommia ulmoides Oliv polysaccharide medium concentration group and model+Eucommia ulmoides Oliv polysaccharide high concentration group. The cells in the blank group were cultured with conventional medium;the cells in the model group cells were cultured with a medium containing 10 ?g/ml IL-1ß, and the cells in the model+Eucommia ulmoides Oliv polysaccharide low concentration group, model+Eucommia ulmoides Oliv polysaccharide medium concentration group and model+Eucommia ulmoides Oliv polysaccharide high concentration group were co-cultured with medium containing 100, 200, 400 µg/ml Eucommia ulmoides Oliv polysaccharide and 10 µg/ml IL-1ß. After the cells of each group were cultured for 24 h, 48 h and 72 h, CCK-8 method was used to detect cell viability. After the cells of each group were cultured for 48 h, flow cytometry and DAPI staining were used to detect cell apoptosis;ELISA method was used to detect the expression of TNF-α, NO, IFN-γ and IL-6 in cells; DCFH-DA method was used to detect the content of ROS in cells;Western blot was used to detect the protein expression of TIMP-1, MMP-13 and NF-κB signaling pathway-related P65 and p-P65;Immunofluorescence staining was used to observe the localization of NF-κB P65 cells. RESULTS: Compared with the blank group, the ATDC5 cell viability and the protein expression of TIMP-1 in the model group reduced (P<0.05), while apoptosis rate, the levels of TNF-α, NO, IFN-γ and IL-6, the content of ROS, the protein expression of MMP-13 and p-P65, and the number of P65+ in the nucleus increased(P<0.05). Compared with the model group, the ATDC5 cell viability and the protein expression of TIMP-1 in the model+Eucommia ulmoides Oliv polysaccharide low concentration group, model+Eucommia ulmoides Oliv polysaccharide medium concentration group and model+Eucommia ulmoides Oliv polysaccharide high concentration group increased (P<0.05), while apoptosis rate, the levels of TNF-α, NO, IFN-γ and IL-6, the content of ROS, the protein expression of MMP-13 and p-P65, and the number of P65+ in the nucleus reduced (P<0.05). CONCLUSION: The results showed that Eucommia ulmoides Oliv polysaccharide could promote proliferation of IL-1ß-induced chondrocyte ATDC5 and inhibit its apoptosis, inflammatory response and matrix degradation. Its mechanism may be related to the inhibition of the activation of NF-κB pathway.

Substrate-Controlled Regioselectivity Switchable [3 + 2] Annulations To Access Spirooxindole Skeletons.

The additive-free [3 + 2] annulation from isatins, amino acids with 2-styrylbenzoxazoles, was described, providing a series of functional and structurally complex 3,3'-pyrrolidinyl-spirooxindole derivatives containing four contiguous and two quaternary stereogenic centers in high yields (up to 95%) and excellent diastereoselectivities (up to >25:1 dr). Interestingly, the reaction exhibits switchable regioselectivity depending on the substrate of amino acids. With proline or thioproline as the substrate, the reaction afforded α-regioselective spirooxindole skeletons. In contrast, when piperidine acid is the substrate, the reaction provided γ-regioselective spirooxindole skeletons.

NGF-Induced Nav1.7 Upregulation Contributes to Chronic Post-surgical Pain by Activating SGK1-Dependent Nedd4-2 Phosphorylation.

At present, chronic post-surgical pain (CPSP) is difficult to prevent and cure clinically because of our lack of understanding of its mechanisms. Surgical injury induces the upregulation of voltage-gated sodium channel Nav1.7 in dorsal root ganglion (DRG) neurons, suggesting that Nav1.7 is involved in the development of CPSP. However, the mechanism leading to persistent dysregulation of Nav1.7 is largely unknown. Given that nerve growth factor (NGF) induces a long-term increase in the neuronal hyperexcitability after injury, we hypothesized that NGF might cause the long-term dysregulation of Nav1.7. In this study, we aimed to investigate whether Nav1.7 regulation by NGF is involved in CPSP and thus contributes to the specific mechanisms involved in the development of CPSP. Using conditional nociceptor-specific Nav1.7 knockout mice, we confirmed the involvement of Nav1.7 in NGF-induced pain and identified its role in the maintenance of pain behavior during long-term observations (up to 14 days). Using western blot analyses and immunostaining, we showed that NGF could trigger the upregulation of Nav1.7 expression and thus support the development of CPSP in rats. Using pharmacological approaches, we showed that the increase of Nav1.7 might be partly regulated by an NGF/TrkA-SGK1-Nedd4-2-mediated pathway. Furthermore, reversing the upregulation of Nav1.7 in DRG could alleviate spinal sensitization. Our results suggest that the maintained upregulation of Nav1.7 triggered by NGF contributes to the development of CPSP. Attenuating the dysregulation of Nav1.7 in peripheral nociceptors may be a strategy to prevent the transition from acute post-surgical pain to CPSP.

Preparation of well-distributed titania nanopillar arrays on Ti6Al4V surface by induction heating for enhancing osteogenic differentiation of stem cells.

Great effort has recently been devoted to the preparation of nanoscale surfaces on titanium-based implants to achieve clinically fast osteoinduction and osseointegration, which relies on the unique characteristics of the nanostructure. In this work, we used induction heating treatment (IHT) as a rapid oxidation method to fabricate a porous nanoscale oxide layer on the Ti6Al4V surface for better medical application. Well-distributed vertical nanopillars were yielded by IHT for 20-35 s on the alloy surface. The composition of the oxides contained rutile/anatase TiO2 and a small amount of Al2O3 between the TiO2 grain boundaries (GBs). This technology resulted in a reduction and subsequent increase of surface roughness of 26-32 nm when upregulating the heating time, followed by the successive enhancement of the thickness, wettability and adhesion strength of the oxidation layer to the matrix. The surface hardness also distinctly rose to 554 HV in the IHT-35 s group compared with the 350 HV of bare Ti6Al4V. The massive small-angle GBs in the bare alloy promoted the formation of nanosized oxide crystallites. The grain refinement and deformation texture reduction further improved the mechanical properties of the matrix after IHT. Moreover, in vitro experiments on a mesenchymal stem cell (BMSC) culture derived from human bone marrow for 1-7 days indicated that the nanoscale layers did not cause cytotoxicity, and facilitated cell differentiation in osteoblasts by enhancing the gene and osteogenesis-related protein expressions after 1-3 weeks of culturing. The increase of the IHT time slightly advanced the BMSC proliferation and differentiation, especially during long-term culture. Our findings provide strong evidence that IHT oxidation technology is a novel nanosurface modification technology, which is potentially promising for further clinical development.

A bioactive coating with submicron-sized titania crystallites fabricated by induction heating of titanium after tensile deformations.

Thermal oxidation technology was widely investigated as one of effective surface modification method for improving the bioactivity and biocompatibility of titanium and its alloys. In this work, the induction heat oxidization method, a fast, efficient, economical and environmental protective technology, was applied to prepare the submicron-morphological oxide coating with variable rutile TiO2 equiaxed crystallites on the surface of pure Ti substrates after cold-drawing with 10-20% deformations. The results showed the plastic-deformed Ti cylinders recrystallized during induction heating treatment (IHT) for 10-20s which resulted in evolution of microstructures as well as slight improvement of microhardness. The surface characteristics of TiO2 crystallites in oxidation layers were determined by the microstructural evolutions of Ti substrate in terms of the nucleation and growth of TiO2 crystallites. Specially, the oxidized surface with 50-75nm roughness and more uniform and finer equiaxed oxide grains remarkablely improved the apatite deposition after bioactive evaluation in 1.5 × SBF for 7 days. This work provided a potential method to create controlled bioactive oxide coatings with submicro-/nano-scaled TiO2 crystallites on titanium substrate in terms of the role of metallographic microstructure in the formation process of titanium oxides.

Isotopic evidence for continental ice sheet in mid-latitude region in the supergreenhouse Early Cretaceous.

Cretaceous represents one of the hottest greenhouse periods in the Earth's history, but some recent studies suggest that small ice caps might be present in non-polar regions during certain periods in the Early Cretaceous. Here we report extremely negative δ(18)O values of -18.12‰ to -13.19‰ for early Aptian hydrothermal zircon from an A-type granite at Baerzhe in northeastern China. Given that A-type granite is anhydrous and that magmatic zircon of the Baerzhe granite has δ(18)O value close to mantle values, the extremely negative δ(18)O values for hydrothermal zircon are attributed to addition of meteoric water with extremely low δ(18)O, mostly likely transported by glaciers. Considering the paleoaltitude of the region, continental glaciation is suggested to occur in the early Aptian, indicating much larger temperature fluctuations than previously thought during the supergreenhouse Cretaceous. This may have impact on the evolution of major organism in the Jehol Group during this period.

[Ecological protection and sustainable utilization of Erhai Lake, Yunnan].

Economic development and increase of population pressure have caused a series of ecological environmental problems of Erhai Lake. These problems include: (1) Quickening of eutrophication process, (2) Decrease of water level and water resources, (3) Habitat deterioration of lakeside zone, and (4) Overfishing and slow depletion of aboriginal fish. Pollutant loading of Erhai Lake is as follows: COD(Cr) 3 008 t x a(-1), TP 137.31 t x a(-1), TN 1 426.35 t x a(-1). According to the mestrophic target of water quality, loading of nitrogen and phosphorus is far above environmental capacity of Erhai Lake. Erhai Lake is now in a pivotal and hypersensitive period of trophic states change, and the position is very critical. Therefore, some countermeasures to solve the problems are presented as follows: (1) Defining the dominant functions of Erhai Lake, (2) Paying attention to the adjustment of the industrial structure and distribution in the course of urbanization, (3) Setting up lakeside zone reserve, (4) Strengthening the control of tourism pollution, (5) Properly adjusting the water level of Erhai Lake, and (6) Some ecological engineering measures for water resources protection in the basin should be taken through collecting and treating of urban sewages, ecological rehabilitating of the main inflowing rivers, constructing of ecological agricultures and improving of rural environment, ecological restoring of aquatic ecosystem, and soil and water conservation.