Search

[Display omitted] • Fluid immiscibility referred by CO 2 -rich and halite-bearing inclusions in arrays. • The cooling and decompression during exhumation triggered fluid immiscibility. • Saline ore fluids are derived from dehydration of evaporative carbonate rocks. • Metamorphic brines drive Cu mineralization in the metasediments. Epigenetic hydrothermal Cu-(Co) deposits are widely distributed in the Zhongtiao Mountains within the Paleoproterozoic Trans-North China Orogen in the North China Craton. Here we investigate the Henglingguan Cu deposit hosted in metasediments to gain insights on the fluid evolution characteristics associated with the ore formation. This Cu deposit is characterized by early disseminated mineralization and late quartz-vein type mineralization. The negative sulfur isotope values (about −10‰) of the vein sulfides suggests a sedimentary rock source for sulfur associated with the hydrothermal Cu mineralization. The coexistence of CO 2 -rich carbonic inclusions and halite-bearing inclusions within a single fluid inclusion assemblage suggests fluid immiscibility in the H 2 O-NaCl-CO 2 system. Based on the fluid phase analysis, our data show that the parent ore fluid was characterized by X(NaCl) of 10 to 20 mol.% (salinity of around 23 to 41 wt% NaCl) and X(CO 2) of 10 to 15 mol.% before fluid immiscibility. The estimated temperature–pressure conditions of 320 to 340 °C and 3.5 to 4.0 kbar based on the carbonic fluid inclusions is suggested to be close to the conditions of fluid immiscibility. In-situ composition analyses of fluid inclusions by LA-ICP-MS show that the ore fluids contained Na, Ca, Fe and Mn, and evolved towards Sr-Ba enrichment. The data are consistent with a metamorphic brine derived from the sedimentary rocks. The brine-rich metamorphic fluids were likely derived from the dehydration and decarbonation of evaporitic carbonate rocks developed on the basin margin or a passive continental margin. The decompression during post-collisional exhumation triggered fluid immiscibility resulting in the quartz vein-type Cu mineralization. [ABSTRACT FROM AUTHOR]

• Tritium transport code about tritium simulation for the external fuel circulating system of CFETR has been developed. • The WCCB blanket and its external loops are integrated based on COMSOL and MATLAB. • Tritium transport analysis for the external fuel circulating system and sensitivity analysis have been conducted. Water cooled ceramic breeder (WCCB) blanket was proposed as one of the candidate blanket schemes of the Chinese Fusion Engineering Test Reactor (CFETR). In this paper, a code simulating tritium transport in WCCB blanket and its external loops has been developed, where zero and two dimensional models are integrated to get more reliable results. The purge gas flow in the breeder zone, heat transfer in the blanket and tritium isotopes mass transport are considered. The isotope exchange in the purge gas and coolant loop are also taken into account in the model. The two dimensional model of the WCCB blanket and zero dimensional model of external loops are integrated to calculate tritium related quantities. The amount of tritium inventory in different components, tritium losses, tritium extracted by the tritium extraction system (TES) and purified by the coolant purification system (CPS) are obtained. The sensitivity analysis about key parameters has also been conducted. [ABSTRACT FROM AUTHOR]

Abstract: Background: Reperfusion therapy is widely utilized for acute myocardial infarction (AMI), so ischemia/reperfusion (I/R) of the heart is frequently encountered in clinical practice. The curative effects of reperfusion therapy for AMI are favourable in most cases, but reperfusion can also cause harmful effect to cardiomyocytes. Hydroxysafflor yellow A (HSYA) is an effective therapeutic agent to alleviate I/R injury, but the mechanisms underlying this therapeutic effect are unknown. Methods and results: The H9c2 cardiomyocyte cell line was incubated with or without HSYA during hypoxia, then it was reoxygenated. In the presence of HSYA, reoxygenation resulted in the upregulated expression and activity of heme oxygenase-1 (HO-1), phosphorylation of Akt, translocation of nuclear factor Nrf2, and most importantly, a reduction in A/R-induced apoptosis. An HO-1 inhibitor completely suppressed HO-1 enzymatic activity upregulated by HSYA and notably diminished the anti-apoptotic effect of HSYA. An inhibitor of PI3K, completely blocked Akt phosphorylation induced by HSYA and partly negated HSYA-induced upregulation of HO-1, translocation of nuclear factor Nrf2 and suppression of apoptosis in the H9c2 cardiomyocytes. Conclusions: Our study suggests that HSYA can provide protection to H9c2 cardiomyocytes against A/R-induced apoptosis. This protective effect largely depends on the upregulation of HO-1 expression through the PI3K/Akt/Nrf2 signaling pathway. [Copyright &y& Elsevier]

It is extremely difficult to effectively incorporate and disperse graphene nanoplatelets into metal matrix by traditional processing methods. In this paper, a novel nanoprocessing method that combines liquid state ultrasonic processing and solid state stirring is presented for fabrication of bulk metal–graphene nanoplatelets nanocomposites. The obtained graphene nanoplatelets reinforced Mg-based metal matrix nanocomposite shows a uniform dispersion of graphene nanoplatelets and dramatically enhanced properties. This novel nanoprocessing route has great potential for the production of ultrahigh performance metal matrix nanocomposites. [ABSTRACT FROM AUTHOR]

Sm-Nd isotope systematics of scheelite is becoming a powerful geochronometer for dating the Au and W ore deposits. However, Sm-Nd isotopic analysis of scheelite is relatively difficult due to the formation of large amounts of tungstic acid (H2WO4) precipitates during the conventional acid decomposition of scheelite. In this study, both the low temperature attack and Teflon bomb acid dissolution methods for Sm-Nd isotope analysis of scheelite have been thoroughly investigated. It has been shown that, for both low temperature attack and Teflon bomb methods, although a large amount of tungstic acid precipitate remains during the 2.5 M HCl acidification process prior to cation exchange separation, only less than 10% of the Sm and Nd remains in the tungstic acid precipitate. On the other hand, it has been found that, for isotope dilution analysis, the spike-sample isotopic equilibration was only completely achieved for the Teflon bomb method and not completely achieved for the low temperature attack method, indicating that the low temperature attack method has possibly not liberated all the rare earth elements (REEs) from the scheelite crystal structure. Consequently, for high precision scheelite Sm-Nd dating purposes, the complex Teflon bomb rather than the simple low temperature attack method should be used in order to completely digest scheelite samples; alternatively, since it has been found that the tungstic acid precipitate formed during the acid dissolution process can be completely dissolved by self-purified low-blank 30% NaOH, a simple low temperature attack method combined with low-blank 30% NaOH dissolution of the remaining tungstic acid precipitate can also possibly be used to completely dissolve the scheelite sample for Sm-Nd isotopic analysis. [ABSTRACT FROM AUTHOR]

We report the discovery of GATA2 as a new myelodysplastic syndrome (MDS)-acute myeloid leukemia (AML) predisposition gene. We found the same, previously unidentified heterozygous c.1061C>T (p.Thr354Met) missense mutation in the GATA2 transcription factor gene segregating with the multigenerational transmission of MDS-AML in three families and a GATA2 c.1063_1065delACA (p.Thr355del) mutation at an adjacent codon in a fourth MDS family. The resulting alterations reside within the second zinc finger of GATA2, which mediates DNA-binding and protein-protein interactions. We show differential effects of the mutations on the transactivation of target genes, cellular differentiation, apoptosis and global gene expression. Identification of such predisposing genes to familial forms of MDS and AML is critical for more effective diagnosis and prognosis, counseling, selection of related bone marrow transplant donors and development of therapies. [ABSTRACT FROM AUTHOR]

• MNOP-H 2 S is highly sensitive to sense H 2 S with a detection limit of 29 nM. • MNOP-H 2 S can monitor mitochondrial basal H 2 S levels. • MNOP-H 2 S is applied for distinguishing cancer cells from normal cells. • MNOP-H 2 S is applied to verify role of H 2 S in endothelial cell migration. Hydrogen sulfide (H 2 S) is recognized as a critical gaseous signaling molecule involved in multiple physiological and pathological processes. The important pathophysiological roles of H 2 S have spurred intense interest in developing fluorescent probes for imaging of H 2 S. Using a piperazidine-bridged styrylpyridinium as the push-pull fluorophore and a 7-nitro-1,2,3-benzoxadiazole moiety as the response group, herein we developed a mitochondria-targeted fluorescent probe MNOP-H 2 S , which exhibited remarkable fluorescence turn-on (>130 fold), large Stokes shift (190 nm), excellent sensitivity and selectivity. Importantly, the probe was characterized by an ultralow detection limit (29 nM), thereby being successfully applied to monitor mitochondrial basal H 2 S levels in various types of cells and zebrafish, to distinguish cancer cells from normal cells (even from each other) and to reveal that the endogenously produced H 2 S in mitochondria is a key mediator for the endothelial cell migration stimulated by vascular endothelial growth factor. [ABSTRACT FROM AUTHOR]

• A possible mechanism for the formation of vacancy dislocation loops in α-Fe is proposed. • Vacancy-NH clusters prefer to shape into 2D clusters, especially on (211) planes. • The presence of H can greatly promote the growth of vacancy dislocation loops. Genetic algorithm was applied to search the energy minimization configuration of vacancy clusters in α-Fe. Molecular statics calculations and dynamics annealing relaxation were employed to calculate the formation and binding energies of vacancies and 3D vacancy or vacancy-hydrogen (H) clusters, as well as 2D vacancy or vacancy-H clusters on (111), (011) and (211) planes. Our calculations show that vacancies prefer to form 3D clusters and vacancy dislocation loops are difficult to form, while vacancy-H clusters prefer to shape into 2D clusters, especially on (211) planes. Since H prefers the directional bonding, a vacancy cluster with H atoms tend to form a vacancy dislocation loop with its slip direction along the 〈100〉 direction and on the (211) habit plane. Our results are consistent with the experimental observations, and provide a possible mechanism for the formation of vacancy dislocation loops in α-Fe. Furthermore, we have also explored how dislocation loops trap self-interstitial atoms, vacancies and H atoms. It is of interest to note that H atoms strongly bound to a 〈100〉 vacancy dislocation loop, and are able to enhance the ability for the dislocation loop to further trap vacancies and reduce its ability to absorb self-interstitial atoms, thus promoting the growth of the 〈100〉 vacancy dislocation loops. [ABSTRACT FROM AUTHOR]

Alumina is regarded as one of the most promising candidate tritium permeation barrier (TPB). Through thermal oxidization of Al-contained alloys Fe–Cr–Al, alumina layer with high tritium permeation reduction ability can be obtained. After bonding this kind of materials with structural materials such as reduced activation ferritic/martensitic (RAFM) steels, it can serve as TPB. In this work, efforts have been done to enhance the hydrogen isotope permeation reduction ability of the alumina layer on the Fe–Cr–Al ferritic steel by optimizing the oxidation process. The oxidation temperature of the Fe–Cr–Al ferritic steel is set to 973 K, which is lower than the final heat treatment temperature of the RAFM steel. Three different atmospheres have been employed for the oxidation process of the Fe–Cr–Al ferritic steel. Gas driven permeation (GDP) experiments have been performed to examine the deuterium permeability of the oxidized Fe–Cr–Al ferritic steel. The deuterium permeability of the Fe–Cr–Al ferritic steel oxidized in argon with 1700 ppm oxygen is 104 times lower than that of the RAFM steel at 823 K. The microstructure and chemical composition of the oxide layer of the Fe–Cr–Al ferritic steel oxidized in three different atmospheres has been clarified using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) methods. It is suggested that oxidizing the Fe–Cr–Al ferritic steel at reduced oxygen atmosphere could inhibit the growth of the iron oxide and chromium oxide in the oxide layer, thereby leading to a dense and compact alumina layer that has excellent hydrogen permeation reduction performance. [ABSTRACT FROM AUTHOR]