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Chloride is the most important anion in ore-forming hydrothermal fluids, and chlorine isotopes are therefore potentially sensitive tracers of the origin and evolution of ore-forming fluids. However, they remain a relatively under-utilized tool in ore deposit geochemistry due to the lack of knowledge of chlorine isotope fractionation during ore-forming processes. Using first-principles density functional theory, this study estimates chlorine isotope fractionation factors for various ore-forming processes. All metal-Cl complexes in hydrothermal fluids are enriched in 37Cl compared to chloride ions, but the change in δ37Cl of the fluid trapped in ore minerals is small after the destabilization of metal-chloride complexes during ore mineral deposition. In the precipitation of evaporite minerals from brine, the sequence of enrichment of the heavy Cl isotope (37Cl) is halite > carnallite > aqueous chloride > kainite > sylvite > bischofite. The results of this study agree with the experimental observations that progressive precipitation of halite from brine lowers the δ37Cl value of the residual fluid until the formation of K-Mg chlorides. In low-temperature deposits, δ37Cl values for fluid inclusions and minerals reflect those of the hydrothermal fluid provenance and the mixing of this fluids with saltwater or basinal brines. In high-temperature magmatic-hydrothermal ore deposits that undergo liquid–vapour phase separation, chlorine isotopes fractionate among phases of silicate melt, vapour and chloride-rich liquid. The considerable range in δ37Cl in fluid inclusions may also reflect fluid mixing and hydrothermal alteration. At ambient temperature, the δ37Cl values may reflect evaporative processes and, in the case of chemical weathering of metallic mineral deposits, may record the supergene enrichment of the metals. This study highlights the use of chlorine isotopes as a new tool for interpreting ore-forming processes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Amphibole-rich clots are vestiges of residual pyroxene-rich precursors from the source after partial melting. • The microgranular enclaves of the Tongshanling granodiorite are reworked restite enclaves. • A model illustrating the formation process of reworked restite enclave has been proposed. • The fertile amphibolitic source is beneficial to the formation of Cu-Pb-Zn-bearing granodiorites in the Nanling Range. Abstract Microgranular enclaves, which can provide important petrogenetic indications for the host granitoids, are commonly observed in the Middle-Late Jurassic Cu-Pb-Zn-bearing granodiorites in the Nanling Range of South China. The origin of these Cu-Pb-Zn-bearing granodiorites is still controversial, with two different hypotheses: crust-mantle mixing and partial melting of the mafic lower crust, primarily based on geochemistry and geochronology. Detailed petrographic and mineralogical studies have been carried out on the Tongshanling granodiorite and its microgranular enclaves to provide new textural and compositional constraints on the petrogenesis. The microgranular enclaves have dioritic compositions with a mineralogy dominated by plagioclase, amphibole, and biotite. Abundant residual materials, such as mafic mineral clots, inherited and metamorphic zircon, and Ca-rich core plagioclase, occur in the enclaves and are in favor of a restite origin. The amphibole-rich clots are considered as vestiges of residual pyroxene-rich precursors from the source. Three different types of amphibole, i.e., magmatic, metamorphic, and magma reworked metamorphic amphibole, have been recognized in the granodiorite and its enclaves. The magmatic amphibole occurs as enclosed and idiomorphic isolated crystals in the granodiorite with Al and Si contents of 1.34–2.12 apfu (atoms per formula unit) and 6.25–6.88 apfu, respectively, and a ΣREE content of 307–764 ppm. The metamorphic amphibole, with a granoblastic triple-junction texture, occurs as aggregated crystals dominantly in the enclaves and a few in the granodiorite. It has actinolitic compositions (Al: 0.31–0.81 apfu, Si: 7.33–7.72 apfu) and distinctly lower contents of incompatible elements (ΣREE: 99–146 ppm). The magma reworked amphibole has intermediate compositions (Al: 0.81–1.59 apfu, Si: 6.71–7.35 apfu, ΣREE: 317–549 ppm) between the magmatic and metamorphic amphibole. The zonal amphibole-rich clots exhibit increasing Al and decreasing Si contents from interior amphibole to exterior amphibole and also from core to rim in amphibole grains, and the outer parts of enclave magmatic zircon have higher ThO 2 + UO 2 contents and lower Zr/Hf ratios than the inner parts, showing the process of magma reworking of the restite enclaves. Based on the textural and compositional evidence, these microgranular enclaves are thought to be reworked restite enclaves. This is also supported by thermobarometric calculation. A model illustrating the formation process of reworked restite enclave has been proposed. Combined with previous experimental studies of partial melting, the Tongshanling granodiorite is deduced to be derived from dehydration melting of amphibolite in the mafic lower crust. The fertile amphibolitic source is beneficial to the formation of Cu-Pb-Zn-bearing granodiorites in the Nanling Range. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Lijia tin deposit is formed at 428–430.5 Ma. • This deposit is genetically related to the Lijia granite. • Ore fluids are generated by mixing of 84% magmatic fluids and 16% meteoric water. • Muscovite records the processes of fluid evolution and fluid-rock interaction. • The interaction between the ore-forming fluids and the host granite plays a key role for the cassiterite precipitation. Early Paleozoic Sn mineralization is rarely reported in South China. Here we carried out the detailed studies of deposit geology, cassiterite U-Pb dating, muscovite geochemistry and H-O isotopes on the Early Paleozoic Lijia Sn deposit in South China to constrain its genesis. The Lijia Sn deposit is hosted in the Yuechengling granitic batholith and characterized by greisen-type and quartz vein-type mineralization. Four stages of alteration and veining are recognized according to mineral assemblages and crosscutting relationships: pre-ore tourmalinization and silicification alteration of the Lijia granite (stage I), cassiterite-tourmaline-quartz vein and associated cassiterite greisen (stage II), and post-ore calcite-quartz-fluorite vein and calcite veinlet (stage III and IV, respectively). Two generations of the cassiterite in the cassiterite greisen, identified by cathodoluminescence imaging, yield the U-Pb concordant ages of 430.5 ± 3.7 Ma and 428 ± 2.2 Ma, respectively. The zircon U-Pb ages and geochemical features of the Lijia granite as well as the characteristics of alteration and mineralization indicate that the Lijia granite is Sn-bearing one and brings about the Sn mineralization. H-O isotopic compositions of the quartz from the Lijia granite reveal that the magmatic fluids have the δ18O values of 10.6–10.7‰ and the δD values of −57‰ to −62‰. The ore-forming fluids (δ18O 6.5–7.4‰, δD −64‰ to −69‰) responsible for cassiterite precipitation are derived from the mixing of magmatic fluids with minor meteoric water whereas more meteoric water is involved in the post-ore calcite-quartz-fluorite vein stage. Based on mineral assemblages, internal textures and chemical compositions, muscovite is divided into four generations from early to late: the Mus 1 and Mus 2 in the cassiterite greisen, the Mus 3 in the cassiterite-tourmaline-quartz vein and the Mus 4 in the phyllic alteration in the stage III. From the Mus 1 to the Mus 3, muscovite Rb, Cs, Zn, Li, V, Sc and Ga contents gradually decrease whereas boron shows an increasing trend, which might have been caused by the successive precipitation of hydrothermal minerals such as muscovite. Significantly higher Sr and Ba contents of the Mus 2 than the Mus 1 are likely related to the decomposition of the K-feldspar and plagioclase in the host granite. The combination of the precipitation of the early mineral phases, the decomposition of K-feldspar and the involvement of a large amount of meteoric water gives rise to the decrease of W, Sn, B, Rb, Cs and Sr contents and the increase of Ba, Ti, Mg, Li, Sc, V, Cr, Ga, Nb and Ta contents of the Mus 4 in the stage III. A key mechanism responsible for the formation of the Lijia Sn deposit is the interaction between the ore-forming fluids and the host granite. This study confirms the Early Paleozoic tin mineralization event in South China. [ABSTRACT FROM AUTHOR]

The Nanling Range in South China hosts numerous W–Sn–rare metal deposits associated with several cycles of polygenetic granitic intrusions. In the Wangxianling area of the middle Nanling Range, igneous intrusions include the Wangxianling and Hehuaping granite plutons and more than 20 granite porphyry dykes. The Wangxianling pluton has a central phase of medium-grained tourmaline two-mica granite and a marginal phase of medium-grained tourmaline muscovite granite. The pluton hosts several tungsten deposits including Shuiyuanshan and Yejiwo. Mineralization type is dominantly scheelite greisen, with subordinate scheelite skarn and wolframite–quartz veins. The Hehuaping pluton composed of coarse-grained biotite granite and granite porphyry dykes to the east of the Wangxianling pluton have an associated Hehuaping tin deposit with tin skarn and subordinate porphyry and greisen mineralization. In situ zircon and cassiterite U–Pb dating, molybdenite Re–Os and muscovite 40 Ar– 39 Ar dating techniques are used to refine the age spectra of granitic rocks and W–Sn mineralization in the Wangxianling area. Granites of the Wangxianling pluton have zircon U–Pb ages of ~ 224 Ma. Tungsten-bearing quartz veins from both the Shuiyuanshan and Yejiwo tungsten deposits have an average molybdenite Re–Os isochron age of ~ 224 Ma, and muscovite of scheelite greisen from the Shuiyuanshan tungsten deposit yields a 40 Ar– 39 Ar plateau age of 214 Ma. The two mineralization ages are consistent with the zircon U-Pb age of the Wangxianling pluton indicating a close association between pluton emplacement and W mineralization in the Late Triassic. Both the Hehuaping pluton and granite porphyry dykes have zircon U–Pb ages of ~ 156 Ma. In situ LA–ICP–MS U–Pb dating of cassiterite in both the tin skarn and tin greisen yields an average age of ~ 156 Ma, showing that the Sn mineralization occurred at a similar time to the Late Jurassic granitic magmatism. Thus, two mineralization events are identified in the Wangxianling area, and include an earlier W dominant mineralization event and a later Sn dominant mineralization event. The earlier event is related both spatially and temporally to intrusion of the Late Triassic S-type Wangxianling granite pluton, whereas the later mineralization is associated both spatially and temporally with intrusion of the Late Jurassic Hehuaping A 2 -type granite pluton and A 2 -type granite porphyry dykes. [ABSTRACT FROM AUTHOR]

Abstract: Data centers consume anywhere between 1.7% and 2.2% of the United States’ power. A handful of studies focused on ways of predicting power consumption of computing platforms based on performance events counters. Most of existing power-consumption models retrieve performance counters from hardware, which offer accurate measurement of energy dissipation. Although these models were verified on several machines with specific CPU chips, it is difficult to deploy these models into data centers equipped by heterogeneous computing platforms. While models based on resource utilization via OS monitoring tools can be used in heterogeneous data centers, most of these models were linear model. In this paper, we analyze the accuracy of linear models with the SPECpower benchmark results, which is a widely adopted benchmark to evaluate the power and performance characteristics of servers. There are 392 published results until October 2012; these servers represent most servers in heterogeneous data centers. We use R-squared, RMSE (Root Mean Square Error) and average error to validate the accuracy of the linear model. The results show that not all servers fit the linear model very well. 6.5% of R-squared values are less than 0.95, which means linear regression does not fit the data very well. 12.5% of RMSE values are greater than 20, which means there is still big difference between modeled and real power consumption. We extend the linear model to high degree polynomial models. We found the cubic polynomial model can get better results than the linear model. We also apply the linear model and the cubic model to estimate real-time energy consumption on two different servers. The results show that linear model can get accurate prediction value when server energy consumption swing in a small range. The cubic model can get better results for servers with small and wide range. [Copyright &y& Elsevier]

[Display omitted] • Two stages of fluid exsolution are recognized in the Weijia W skarn deposit. • F-rich magmatic fluids are enriched in REEs, Y, Nb, Ta with flat REE patterns. • F consumption is critical for the compositional evolution of F-rich mineralizing fluids. • Combined garnet and scheelite trace elements are powerful in tracking W skarn mineralization. Fluid evolution is an essential subject in the studies of hydrothermal ore-forming processes. Garnet and scheelite prevail in W-bearing skarn deposits and record plentiful information on W skarn mineralization. In-situ LA-ICP-MS trace element analyses have been carried out on the garnet and scheelite from the F-rich Weijia W deposit in South China to constrain the processes of fluid evolution and W skarn mineralization. The Weijia W deposit mainly consists of calcic and magnesian skarns and was formed through six stages of alteration and mineralization. Two stages of fluid exsolution are recognized in the magmatic-hydrothermal system. The earlier exsolved fluids are Cl-rich with rightward-sloping REE patterns and result in pre-ore skarnization. The later exsolved fluids are F-rich with relatively flat REE patterns and are responsible for W mineralization. The pre-ore garnets are LREE-enriched and HREE-depleted whereas the syn-ore garnets are LREE-depleted and HREE-enriched with lower δ Eu values than the former, denoting a transition from wall rock-controlled to magmatic fluid-dominated fluid-rock interaction. Combined with the skarn occurrences, mineral assemblages, and garnet textures, it is revealed that the mechanism of skarn formation shifts from more diffusive metasomatism under lower water/rock ratios to more advective metasomatism at higher water/rock ratios. The advective metasomatism with a high flux of ore-forming fluids is hydrodynamically favorable for the consequent W mineralization. The earliest-formed scheelite is akin to the host granite porphyry in REE patterns and can reflect the features of initial mineralizing fluids. It has high ΣREE (1255–5059 ppm), Y (616–1416 ppm), Nb (585–2629 ppm), Ta (14–248 ppm), Mn (up to 1977 ppm) and low Mo (mostly < 1000 ppm) contents, indicating that the primary F-rich magmatic fluids are reduced and enriched in REEs, Y, Nb, and Ta. The contents of ΣREE, Y, Nb, and Ta in scheelite are decreasing with the evolution of the F-rich mineralizing fluids. The latest-formed scheelites have distinctly lower ΣREE (2.9–140 ppm), Y (0.01–4.1 ppm), Nb (1.7–77 ppm), and Ta (0.04–0.19 ppm) contents and higher (La/Yb) N ratios and δ Eu values. They show 1:1 positive correlation of Eu N vs. Eu N * and have high Mo (up to 129466 ppm) and low Mn (as low as 3.4 ppm) contents, implying involvement of meteoric waters in the evolved ore-forming fluids and an oxidizing condition. Fluid-rock interaction, mineral precipitation, and fluid mixing largely control the process of fluid evolution. Fluorine consumption due to the formation of fluorite and the other F-rich minerals is vital for the compositional evolution of F-rich mineralizing fluids. The decrease of F concentration in fluids will depress the solubilities of REEs, Y, Nb, and Ta and enhance the LREE/HREE fractionation. Greisenization and skarnization induced the neutralization of the acidic W-bearing fluids and the liberation of Ca from the granite porphyry and carbonate strata and then triggered the scheelite precipitation. The carbonate strata contain abundant Ca and the granite porphyry is poor in Ca, and thus the economic W mineralization dominantly occurs in the skarns. [ABSTRACT FROM AUTHOR]

Abstract: Alzheimer''s disease (AD), the most common form of dementia, is characterized by the deposition of amyloid plaques, accumulation of fibrillary tangles in neurons, neurite degeneration, loss of neurons, and a progressive loss of cognitive function. The pathogenesis of AD is not fully understood, and no strong disease-modifying therapies are currently available. Recent studies suggest that the pan-neurotrophin receptor, p75NTR, is a critical factor involved in the pathogenesis of AD. In this review, we have discussed the roles of p75NTR in the production of amyloid-beta (Aβ), neuronal death, neurite degeneration, tau hyperphosphorylation, cell cycle re-entry and cognition decline in AD, and proposed that p75NTR is a potential target for the development of therapeutic drugs for AD. Finally we provide perspectives in developing various therapeutic strategies targeting different aspects of AD hallmarks which relate to p75NTR functions and breaking the p75NTR-mediated positive feedback loop which promotes the cascades in the pathogenesis of AD. [Copyright &y& Elsevier]

[Display omitted] • The Sanxianba granite is originated from the partial melting of the Banxi Group metasandstone. • Tungsten and volatiles are concentrated and form a W-rich evolved melt during fractionation. • Exsolved fluids from the evolved melt react with granite, forming veinlet-disseminated scheelite mineralization. Whole rock geochemistry combined with spatially resolved geochemistry of zircon, apatite, biotite and plagioclase allows us to uncover the magmatic processes leading to ore formation at the Muguayuan deposit. The Sanxianba granite, associated with the Muguayuan veinlet-disseminated scheelite deposit, is located in the middle of the Jiangnan Orogen. Whole rock Sr and Nd isotopes, and zircon Lu-Hf isotopes suggest it might originate from the Neoproterozoic Banxi group strata. The Rb element modeling shows that, after ~35% of partial melting, the Banxi group metasandstone can generate the primary Sanxianba melt with 164 ppm Rb and 21 ppm W. The intra-/intercrystal texture and compositions of zircon and plagioclase indicate that W and other elements such as HREE, Th, U, Nb, Ta, and P increase in the melt during fractional crystallization. The water content in the early Sanxianba magma, calculated through the plagioclase-hydrometer, is ~4.4 wt%, and its enrichment in the melt is reflected by the increasing water content in biotite with fractionation. F content in the early apatite is relatively high and invariable but further elevated in the late apatite. Chlorine, LREE and Na contents in the early apatite also present an enrichment trend. When H 2 O and Cl start to be saturated with the magma fractionation in the deep magma chamber, Cl-, Na-, and LREE-rich but W-poor fluid exsolves from the melt, resulting in the albitization and chloritization of feldspar and biotite phenocrysts, respectively. The subsequent decrease of Cl, Na 2 O and La 2 O 3 in the late apatite record this first fluid exsolution. Fluorine, P, H 2 O and W continue to enrich in the evolved melt with fractionation after the Cl-rich fluid exsolution. These fluxing components reach oversaturation during the shallow-ward emplacement of the magma, forming the F-, P- and W-rich fluids. The apex of the intrusion cools and forms a solid barrier, which prevents the escape of fluids. The exsolved fluids from the underlying magma continuously supply upward and react with the apex along fractures, resulting in greisenization and phyllic alteration. During alteration, Ca is released from calcium-rich plagioclase and combines with tungsten in the fluids to form scheelite mineralization. Magma evolution leading to the tungsten mineralization may be also the general scenarios in the other granite-related veinlet-disseminated scheelite deposits. [ABSTRACT FROM AUTHOR]

The geochemistry of Ba is commonly used to study igneous processes and fluid-melt interaction in subduction zone and granitic environments. Recent advances in analytical techniques have also indicated that Ba isotope geochemistry has the potential to significantly augment these studies. Understanding the Ba isotope fractionation mechanisms is thus critical if this potential is to be fully realized. Hence, we have used the first-principles calculations based on the density functional theory (DFT) and long-time ab initio molecular dynamics (AIMD) simulation to calculate Ba isotope fractionation during felsic magma evolution. In fluids, the reduced partition function ratio (β factor) of aqueous Ba2+ is highly variable, depending on the coordination number (n) of H 2 O in the first hydration shell. At ambient surface conditions on the Earth, n = 8 best represents the aqueous Ba2+ species in natural fluid, and the temperature-dependent equilibrium Ba isotope fractionation between barite/witherite and fluids can be described by the relationships: 103ln α witherite-fluid = −0.00009×(106/T2) 2 + 0.0603×(106/T2) + 0.0003 and 103ln α barite-fluid = −0.0001×(106/T2) 2 + 0.0648×(106/T2) + 0.0004, which is consistent with previous theoretical and experimental studies. In hydrothermal fluids, the hydration number of Ba2+ varies from 4 to 6 at high P-T, and the cumulative average of 103lnβ is derived to be 0.0798 ± 0.005‰ in 923.15 K and 0.2 GPa. In silicate minerals, the enrichment of heavy Ba isotopes decreases in the sequence of muscovite > microcline ≈ celsian ≈ sanbornite > barylite > phlogopite. Variations in Ba concentrations and the degree of Al-Si disordering only induce limited Ba isotope fractionation, which would be hard to distinguish analytically. At high temperatures (> 600 °C), the melt phase is enriched in heavy Ba isotopes relative to any coexisting aqueous fluid and crystallizing minerals. During the early stages of felsic magma differentiation involving plagioclase crystallization as the main mineral, the δ138/134Ba and concentration in the residual melt remain close to their initial values, but any fluid exsolved from the melt will have light δ138/134Ba values. The high Ba distribution coefficient of K-feldspar means that the resultant K-feldspar granite inherits > 90% of the Ba contained in the initial magma reservoir. Hence, the δ138/134Ba of K-feldspar is close to that of the initial melt. During the final stage of felsic magma evolution, mixing of exsolved fluids from deeper reservoirs may significantly reduce the δ138/134Ba of the now Ba-depleted melt, and can account for the low δ138/134Ba values measured in highly differentiated leucogranites and pegmatites. [ABSTRACT FROM AUTHOR]

Background. To eliminate mother-to-child transmission of syphilis, the Chinese government recommends a treatment regimen that slightly differs from the World Health Organization- (WHO-) recommended treatment. However, little is known about their difference in efficacy. This study is aimed at comparing the effect of China-recommended and WHO-recommend treatment regimens on adverse pregnancy outcomes (APOs) and at examining associated risk factors of APOs among syphilis-seropositive women. Methods. Using the syphilis registry data, we retrospectively collected data from 4488 syphilis-infected pregnant women in Guangzhou during 2011-2018. Multivariate analyses were used to investigate the association between treatment regimens and APOs (ectopic pregnancy, spontaneous abortion, stillbirth, preterm birth or low birth weight, newborn smaller than gestational age, congenital syphilis, and infant death) and the association between risk factors and APOs. Results. Of 3474 participants, 27.3% had at least one APO. Compared to those receiving WHO-recommended treatment, women who received China-recommended treatment were less likely to have APOs (odds ratio (OR) 0.47, 95% confidence interval (CI) 0.38-0.57), whereas those who received no treatment had 1.6 times higher odds of experiencing APOs. One common risk factor across different APOs was high levels of log2-transformed toluidine red unheated serum test (TRUST) titers before treatment (OR 1.14, 95% CI 1.10-1.19). China-recommended treatment was effective in reducing APOs for those with TRUST ≥ 1 : 8 (OR 0.21, 95% CI 0.14-0.29) and those with TRUST < 1 : 8 (OR 0.62, 95% CI 0.50-0.77). Conclusions. Syphilis-seropositive women receiving China-recommended treatment had lower odds of APOs, especially when TRUST titers before treatment were high. Findings can be used to guide health professionals to reduce APOs among syphilis-infected mothers and promote nationwide use of China-recommended treatment. [ABSTRACT FROM AUTHOR]

Yunlong tin deposit is a medial-sized hydrothermal deposit in western Yunnan province of China. This deposit is unusual because the tin mineralization occurs exclusively within the migmatite bodies. The genesis of the ore deposit has been hotly debated and various models have been proposed including granite-related magmatic–hydrothermal and migmatitic–hydrothermal origins. This paper reports a systematic trace and rare-earth elements (REE) geochemical study in tourmaline and cassiterite from the orebodies and associated migmatites from the Yunlong tin deposit. Tourmaline and cassiterite from this deposit show light REE (LREE)-enriched patterns with variable Eu and Ce anomalies consistent with hydrothermal fluids being derived from local high-grade metamorphism and migmatization. The data suggest that tourmaline and cassiterite were likely precipitated from migmatitic–hydrothermal fluids and indicate that the Yunlong tin deposit was probably formed during migmatitic–hydrothermal process. The high concentrations of transition metals (e.g., Sc, Ti, V, Cr, Mn, and Zn) in tourmalines are also consistent with this model. The high concentrations of Sn, Sr, and especially Sc, V, and Cr in tourmalines can be used to discriminate tourmaline from barren deposits relative to those associated with economic tin mineralization. [Copyright &y& Elsevier]

[Display omitted] • The Shiquanhe-Yarlun Zangbo geothermal field enriched in rare alkali metal resources. • Himalayan leucogranite are typical of S-type granites. • Partial melting of metasediments and intense water–rock interaction promote RAMs enrichment. • Strong adsorption controls the hyper enrichment of rare metals during silica precipitation. Geothermal waters in the Shiquanhe-Yarlun Zangbo geothermal field of southern Tibet are highly enriched in rare alkali metals (RAMs), which form a globally unique geyserite Cs-deposit. Boron isotopes, together with the geochemistry of a local leucogranite, geothermal springs and geyserite were investigated to constrain the migration and accumulation of RAMs in the geyserite cesium deposit. The δ11B values of −9.7‰ to −8.4‰ in tourmalines from the Himalayan leucogranite have shown typical S-type granites. A mass balance calculation indicates that the magma of the S-type granite contained < 10 % dehydrated fluid, which resulted in an enrichment of RAMs by 4–5 times during the partial melting of crustal materials, compared to that in the UCC. The linear relationships of ΣRAMs vs. B and Na + K vs. soluble Si, indicate that further enrichment of RAMs in the geothermal fluids was promoted by intense water–rock interaction at temperatures of 210 to 250 °C in the geothermal system reservoir. A strong adsorption process controlled the hyper enrichment of RAMs (especially Cs) during silica precipitation from the upwelling geothermal water, with the sharp decreases in temperature and pressure leading to the enrichment of Cs in fresh geyserites. Despite loss of RAMs during dehydration of the geyserite during phase transformation from opal-A, opal-CT, and chalcedony to quartz, freshly deposited geyserites have great potential for exploration of RAMs resources in this area. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • 23 Columbite-tantalite ages from 14 Nb–Ta deposits in South China were reported. • Five distinct Nb–Ta mineralisation events (424–391, 248–204, 160–150, ∼130, and ∼90 Ma) in South China were revealed. • Some suggestions for future Nb–Ta exploration in South China were given. Abstract South China hosts many Nb–Ta deposits that show evidence for episodic mineralization, which were generated during the emplacement of composite granites. To constrain the spatio-temporal distribution of Nb–Ta mineralisation in the region and to identify future targets for mineral exploration, we used in situ laser ablation-inductively coupled plasma-mass spectroscopy to date 23 columbite-tantalite group mineral (CGM) samples from 14 Nb–Ta deposits. Our CGM U–Pb data, supplemented by previous results, reveal five distinct Nb–Ta mineralisation events in South China as follows: (1) Late Silurian–Middle Devonian (ca. 424–391 Ma; e.g., the Xigang and Nanping deposits in eastern Jiangxi and western Fujian Provinces); (2) Triassic (ca. 248–204 Ma; e.g., the Houxi, Cunxin, Dongtounan, Shenkeng, Limu and Gaoling deposits in western Guangdong Province and northeastern Guangxi Zhuang Autonomous Region; (3) Late Jurassic (ca. 160–150 Ma; e.g., the Gedongping, Yichun, Laiziling, Jianfengling and Jinzhulong deposits in Guangxi, Jiangxi and Hunan Provinces); (4) Early Cretaceous (ca. 130 Ma; e.g., the Huangshan and Songshugang deposits in northeastern Jiangxi province); and (5) Late Cretaceous (ca. 90 Ma; e.g., the Jiepailing deposit, located along the boundary between Hunan and Jiangxi Provinces). We show that Nb–Ta mineralisation in South China was controlled by multiple tectono-magmatic events. Our CGM samples yielded Caledonian (ca. 424–391 Ma), early Indosinian (ca. 248 Ma) and late Yanshanian (ca. 130 Ma) ages, indicating that Nb–Ta mineralisation was abundant during these times and should form the focus for future studies of mineralisation in the region. Early Triassic granite in the Guangning Nb–Ta metallogenic district in western Guangdong Province, Indosinian and early Yanshannian granites in the Miao'ershan–Yuechengling batholith in northeastern Guangxi, and the Late Cretaceous Lingshan batholith in northern Jiangxi Province are identified as targets for future Nb–Ta exploration. [ABSTRACT FROM AUTHOR]

The Late Triassic Muguayuan W deposit is located in the middle of the Jiangnan Orogen, South China. This deposit is characterized by veinlet-disseminated W mineralization that developed in the Sanxianba granitic porphyry stock. The ore minerals are mainly scheelite with minor molybdenite and wolframite. Scheelite mineralization was closely related to greisenization and phyllic alteration, and took place in two stages. Stage I involved scheelite ± wolframite ± molybdenite + quartz veinlet and disseminated mineralization, whereas Stage II resulted in scheelite + quartz + sericite veinlet mineralization. Sulfide and quartz + calcite ± pyrite veinlets formed during the post-ore stage. Scheelites from the two mineralization stages have different textures and compositions. Cathodoluminescence (CL) images of Stage I scheelites reveal two generations of growth (I-a and I-b). Stage I-a scheelite is dark under CL with oscillatory zoning, and has light rare earth element (LREE)-enriched chondrite-normalized patterns, negative Eu anomalies, and high total REE contents. Stage I-b scheelite forms rim overgrowths on Stage I-a scheelite, is bright under CL, and shows positive Eu anomalies and relatively low REE contents. Although Stage II scheelites are nearly uniform under CL, they can be subdivided into two generations according to their REE systematics. Stage II-a scheelite yields middle REE (MREE)-enriched chondrite-normalized patterns, with negative Eu anomalies, whereas Stage II-b scheelite has MREE-depleted patterns with positive Eu anomalies. Minor amounts of apatite formed in both stages of mineralization. Stage I apatite contains 1370–1930 ppm Mn and 97.7–127 ppm Sr, whereas Stage II apatite has lower Mn (111–158 ppm) and higher Sr (2170–4690 ppm) concentrations. The distinct trace elements compositions of the scheelite and apatite from the two stages identify two ore-forming fluids that had different origins and compositions. The ore-forming fluids in Stage I-a were relatively reduced magma-derived fluids with high Mo, Mn, Nb, and Ta, and low Sr. Fluid modeling shows that the initial fluids of Stage I-a were LREE-enriched with negative Eu anomalies, similar to the Sanxianba granitic porphyry. Precipitation of early apatite and scheelite, as well as plagioclase decomposition, altered the fluid composition and led to relative depletions in REE, Nb, and Ta, and increases of Eu and Sr in the Stage I-b fluids. Cooling of these fluids and the addition of recycled meteoric water led the fluids to become relatively oxidized and Sr-rich; Stage II scheelite precipitated from these fluids. Precipitation of Stage II-a scheelite resulted in the Stage II-b fluids becoming progressively MREE-depleted. Extensive alteration, especially greisenization and phyllic alteration, led to plagioclase decomposition, which provided the Ca necessary for scheelite mineralization. This process was important in generating the W mineralization in the Muguayuan deposit, and perhaps for other granite-hosted, veinlet-disseminated scheelite deposits in the Jiangnan Orogen. [ABSTRACT FROM AUTHOR]

Veinlet-disseminated and vein-type tungsten deposits are important tungsten resources in South China and show remarkable diversity in dominant tungsten minerals. To better understand their genesis, scheelite from the Shimensi veinlet-disseminated deposit and wolframite from the Xihuashan and Piaotang vein-type deposits were selected to conduct in-situ laser ablation-inductively coupled plasma-mass spectrometry trace element analyses. The Shimensi tungsten mineralization occurs in intensively altered granitic rocks and is characterized by scheelite. Two generations of scheelite in a single grain can be identified by cathodoluminescence (CL) imaging. The early scheelite (dark domains in CL images) is characterized by nearly flat chondrite-normalized REE (REE N ) patterns with significantly negative Eu anomalies, whereas the late one (bright domains in CL images) shows light rare earth element (LREE)-enriched REE N patterns and obviously positive Eu anomalies. The former has higher REE, Na, Nb and Ta and lower Sr contents than the latter. The Xihuashan and Piaotang wolframite-quartz veins are developed in greisenized granite (type I) and metasedimentary rocks (type II). Both types of wolframite show LREE-depleted patterns, but type I exhibits strongly negative Eu anomalies and type II positive Eu anomalies. Type I contains higher REE, Nb and Ta concentrations, and lower FeO/MnO ratios than type II. Variations of Eu anomalies and trace element compositions in both scheelite and wolframite can be used to decipher the origin and processes of tungsten mineralization. Both the early scheelite and wolframite (type I) display significantly negative Eu anomalies and have high REE, Nb and Ta contents, suggesting that the initial ore-forming fluids were of magmatic origin. Precipitation of tungsten minerals and alteration would effectively modify the composition of ore-forming fluids. Deposition of the early tungsten minerals would lower REE, Nb and Ta in the mineralizing fluids, leading to depletion of these elements in the late ones. Although both the type I and II wolframite have different REE contents and Eu anomalies, they show similar left-dipped REE N patterns, implying that compositional variation of fluids is likely driven by crystallization of wolframite during the processes of fluid evolution. In contrast, the elevated LREE/HREE (heavy rare earth element) ratios, δEu (Eu N /Eu N ∗ ) values and Sr abundances in the late scheelite are possibly caused by the decomposition of plagioclase and K-feldspar. Alteration plays an important role in the formation of veinlet-disseminated scheelite deposits. It can be concluded that vein-type wolframite mineralization is mainly formed by filling and that veinlet-disseminated scheelite mineralization is associated with metasomatism. [ABSTRACT FROM AUTHOR]

An efficient tandem route to the synthesis of triazacyclopenta[cd]indenone derivatives of the cyclazine family has been developed. Target compounds were obtained in moderate to good yields by Groebke–Blackburn–Bienaymé reaction involving a potassium carbonate promoted intramolecular aminolysis. This in turn will set the stage for a wide application of this useful reaction for the synthesis of structurally diverse polyheterocyclic skeletons containing the imidazo[1,2‐a]pyridine ring. [ABSTRACT FROM AUTHOR]

The thermodynamic and structural parameters of the W/O microemulsion systems 12-4-12(a), C12mimBr (b) þ butan-1-ol þ octane þ 5% NaCl solution were studied and compared at different temperatures. The thermodynamic properties of the mixed surfactants W/O microemulsions 12-4-12/SDS(a), C12mimBr/SDS (b) þ butan-1-ol þ octane þ 5% NaCl solution were also studied at different temperatures. They were compared with each other and compared with the above W/O microemulsions containing the single surfactant. In the mixed-surfactants W/O microemulsions, both Xo a (the mole fraction of the alcohol in the oil phase) and Xi a (the mole fraction of the alcohol in the interfacial layer) are significantly lower, while - ΔGo o→i is significantly higher, compared with the W/O microemulsions containing the single surfactant. As temperature increases, Xo a decreases while both Xi a and - ΔGo o→i increases. The standard enthalpy change (ΔHo o→i ) and entropy change (ΔSo o→i ) of transferring alcohol from the continuous oil phase to the interfacial layer are all negative in value. The order of magnitude for both ΔDo o→i and ΔSo o→i values is as follows: 12-4-12/SDS < C12mimBr/SDS < 12-4-12 < C12mimBr. As temperature increases, ΔHo 8-i values slightly decrease, while ΔSo o→i values slightly increase. This leads to the decrease of the - ΔGo o→i values. [ABSTRACT FROM AUTHOR]

Serpentinites entering subduction zones show selective enrichment in trace elements and are the most important carriers of B in this setting. The evolving B isotopic composition (δ11B) of serpentinite is used in studying water-mediated interactions between mantle and crust in subduction zones, but we lack a full understanding of the processes controlling B isotope fractionation during serpentinization that would allow this tracer to be better utilized. Boron isotope fractionation between lizardite/forsterite/diopside and aqueous fluids is investigated using quantum mechanics (density functional theory, DFT) and the first-principles molecular dynamics simulation (FPMD) here. The 11B enrichment sequence in minerals follows the order of forsterite > clinopyroxene (diopside) > white mica > phlogopite > lizardite. On the basis of boron configurations in aqueous fluid acquired from FPMD simulations based on DFT, the reduced isotopic partition function ratio (β-factor) of aqueous B(OH) 3 and B(OH) 4 − are 1000lnβ B(OH)3 = −20.1 + 37.07(1000/T) + 8.2(1000/T)2 and 1000lnβ B(OH)4- = −13.94 + 24.43(1000/T) + 9.12(1000/T)2 at the P-T range of 0–500 MPa and 298–1000 K. This theoretical approach gives an equilibrium B isotope fractionation of Δ11B lizardite-fluid = 15.89–22.88(1000/T) - 0.19(1000/T)2 between lizardite and neutral serpentinization fluid in the temperature range from 298 to 673 K. By contrast, the boron isotope fractionation between minerals formed as the slab descends (e.g., forsterite, diopside) and fluid released from subducted crustal lithologies is limited, indicating that secondary olivine minerals may inherit the δ11B signatures of the dehydrated serpentinites. This study provides new insights into how B isotopes can constrain boron sources and pathways in subduction zones, and trace phases recycled into the deep mantle and their later recycling in ocean island basalts. [ABSTRACT FROM AUTHOR]

Verticillium wilt of cotton is a severe soil-borne disease caused by Verticillium dahliae worldwide. Phytotoxin of V. dahliae (VD-toxin) plays a crucial role in inducing the wilt syndrome in cotton. In this study, spores of four antagonistic isolates were used in the form of powdered biocontrol agent (BCA) to protect cotton from the toxic and wilting effect of VD-toxin. The application of powdered Streptomyces BCA to soil at the time of sowing considerably enhanced defense-related enzyme activities and increased ortho-dihydric phenol and lignin contents in cotton plants after 6 week cultivation in a greenhouse. Compared to the control treatment, Streptomyces BCA treatment severely enhanced defense-related responses in cotton plants within 24 h post-VD-toxin treatment, which further decreased the accumulation of malondialdehyde and mitigated the losses of root activity, leaf total chlorophyll content, and leaf water content. Ultimately, the Streptomyces BCA treatment weakened the pathogenic effect of VD-toxin on cotton and reduced Verticillium wilt by 20.5% to 68.2% at 72 h. These results indicate that the induction of systemic disease resistance and the reduction of VD-toxin's pathogenic effect are two important mechanisms of antagonistic Streptomyces BCA for biocontrol of Verticillium wilt of cotton. [ABSTRACT FROM AUTHOR]

The solubilizations of dense nonaqueous phase liquids trichloroethylene (TCE), carbon tetrachloride (CCl 4 ), 1,2-dichloroethane (DCE) and tetrachloroethene (PCE) in microemulsions containing mixed surfactants 1- dodecyl-3-methylimidazolium bromide ( C 12 mimBr ) and sodium lauryl sulfate (SLS), were studied by application of the ε - β fishlike phase diagram approach. It was found that the three-phase microemulsions would form at two X C 12 mimBr ranges of 0.0–0.1 and 0.8–1.0. Compared to the microemulsions containing single surfactant C 12 mimBr or SLS, the mixed C 12 mimBr -SLS microemulsions have lower solubility of the alcohol ( ε B ) and lower mass fraction of the alcohol in the interfacial layer ( A S ), but higher solubilization parameter ( SP *) values. The order of magnitude for the solubilization ability of the chlorohydrocarbons in the C 12 mimBr -SLS mixed ( X C 12 mimBr = 0.8) microemulsion systems is: TCE > CCl 4 > PCE > DCE. This is consistent with the results of the literature. As the mass fraction values of oil in oil-water mixture ( α ) increase, ε B and A S decrease, while SP * increases. The effects of both NaCl contents ( w ) and temperatures (T) on the physicochemical parameters of the microemulsions were also investigated. As the NaCl contents and the temperatures increase, the solubilization ability of the microemulsions increases. [ABSTRACT FROM AUTHOR]

Brain-derived neurotrophic factor (BDNF) plays important roles in neural stem cell (NSC) growth. In this study, we investigated whether BDNF exerts its neurotrophic effects through the Wnt/β-catenin signaling pathway in human embryonic spinal cord NSCs (hESC-NSCs)in vitro. We found an increase in hESC-NSC growth by BDNF overexpression. Furthermore, expression of Wnt1, Frizzled1 and Dsh was upregulated, whereas GSK-3β expression was downregulated. In contrast, hESC-NSC growth was decreased by BDNF RNA interference. BDNF, Wnt1 and β-catenin components were all downregulated, whereas GSK-3β was upregulated. Next, we treated hESC-NSCs with 6-bromoindirubin-3′-oxime (BIO), a small molecule inhibitor of GSK-3β. BIO reduced the effects of BDNF upregulation/downregulation on the cell number, soma size and differentiation, and suppressed the effect of BDNF modulation on the Wnt signaling pathway. Our findings suggest that BDNF promotes hESC-NSC growthin vitrothrough crosstalk with the Wnt/β-catenin signaling pathway, and that this interaction may be mediated by GSK-3β. [ABSTRACT FROM PUBLISHER]

The present study evaluates the effects of embryonic age and proteolytic enzymes on the isolation and primary culture of chicken enterocyte and to establish an effective technique for chicken intestinal epithelial cell ( IEC) cultivation. Fourteen-day-old, 16-day-old and 18-day-old embryos (average weight: 52.23 ± 0.76 g, 50.86 ± 0.99 g, 48.98 ± 1.03 g) were the source for preparation of enterocyte culture, and trypsin-ethylene diamine tetraacetic acid, collagenase, thermolysin and combination of collagenase and thermolysin were used for digestion medium. Optimal culture protocols were determined by qualitative assays of proliferation. Cells isolated by using 14-day-old embryo and collagenase obtain the best attachment and growth in culture, and the production of continuously growing IEC cultures. Thus, we conclude that the use of collagenase as a dissociating enzyme and 14-day-old embryo as a source can be advantageously applied to the isolation of chicken IEC and this method may be useful for various applications and basic studies of the intestinal tract concerning such objects as physiology, immunology and toxicology. [ABSTRACT FROM AUTHOR]

J. Neurochem. (2012) 122, 1010-1022. Abstract Amyloid precursor protein (APP) is involved in the pathogenesis of Alzheimer's disease. It is axonally transported, endocytosed and sorted to different cellular compartments where amyloid beta (Aβ) is produced. However, the mechanism of APP trafficking remains unclear. We present evidence that huntingtin associated protein 1 (HAP1) may reduce Aβ production by regulating APP trafficking to the non-amyloidogenic pathway. HAP1 and APP are highly colocalized in a number of brain regions, with similar distribution patterns in both mouse and human brains. They are associated with each other, the interacting site is the 371-599 of HAP1. APP is more retained in cis-Golgi, trans-Golgi complex, early endosome and ER-Golgi intermediate compartment in HAP1−/− neurons. HAP1 deletion significantly alters APP endocytosis and reduces the re-insertion of APP into the cytoplasmic membrane. Amyloid precursor protein-YFP(APP-YFP) vesicles in HAP1−/− neurons reveal a decreased trafficking rate and an increased number of motionless vesicles. Knock-down of HAP1 protein in cultured cortical neurons of Alzheimer's disease mouse model increases Aβ levels. Our data suggest that HAP1 regulates APP subcellular trafficking to the non-amyloidogenic pathway and may negatively regulate Aβ production in neurons. [ABSTRACT FROM AUTHOR]

Sn is generally the dominant form of tin in magnetite-series granites as shown by the presence of cassiterite or its incorporation into Ti-bearing minerals such as biotite and titanite. Little is known about the behavior of tin in magnetite. The Huashan granite is an oxidized tin granite in the Nanling Range, southern China, where it contains magnetite as the dominant Fe oxide mineral. It is included in biotite as an early phase and also as interstitial grains spatially associated with ilmenite, cassiterite, Sn-rich titanite (SnO up to 5.9 wt.%), fluorite and apatite. This association indicates that tin enrichment occurred during the late stage of magma crystallization. Ilmenite lamellae display a trellis structure consistent with features of the 'oxy-exsolution' process of Sn-bearing titanomagnetite precursor. Micro-inclusions of cassiterite (<1 μm in size) are found only within ilmenite lamellae. This suggests that magnetite with cassiterite inclusions is likely an indicator mineral of oxidized tin granites. Although rare in nature, Sn-bearing magnetite from weathered granites where concentrated in stream sediments, may serve as a strategic tracer for tin exploration in granite districts and in placer deposits, in general. [ABSTRACT FROM AUTHOR]

The heavy metal-resistant bacterial strain Cupriavidus metallidurans XXKD-1, was isolated from a 475 m subsurface laneway in the Qixiashan Pb-Zn mine, near Nanjing City in eastern China. The phylogenetic analysis based on the 16S rRNA gene sequence shows that the microorgamism has 99% similarity to C. metallidurans CH34. Minimal inhibitory concentrations (MICs) of metals for the bacterium were determined. The bacterial strain XXKD-1 exhibited high MIC values for various heavy metals and a large spectrum of antibiotic resistance. The order of toxicity of the metals to the bacterium was Cd2+ (1 mM) > Co2+ (2 mM) > Cr3+ (2.5 mM) > Ni2+ (3 mM) > Cu2+ (3.5 mM) > Mn2+ (6 mM) > Zn2+ (10 mM) in Tris minimal broth media. Metal bioaccumulation was determined during the course of growth. C. metallidurans strain XXKD-1 is a very efficient biosorbent. It can remove 74% Mn, 53% Cd, 52% Co, 48% Zn and 4% Cr in the cell walls and 4% Mn, 12% Cd, 11% Co, 9% Zn and 50% Cr in intracellular spaces during the active growth cycle (using initial heavy metal concentrations of 0.5 mM). However, it did not efficiently accumulate Cu and Ni, removing only 12% and 10% with total metal biosorption capacities of 3.8 mg/L (0.06 mM) and 3.1 mg/L (0.053 mM), respectively. Because C. metallidurans cells could grow in the presence of elevated concentrations of metals and present relatively high heavy metal biosorption capacities in aerobic conditions, this bacterium may have potential applications for the in-situ bioremediation of heavy metal-contaminated aqueous (or soil) systems in mine ecosystems. [ABSTRACT FROM AUTHOR]

The phase behavior and the solubilization ability of the microemulsion systems containing mixed oils: sodium lauryl sulfate (SDS) + butan-1-ol + oil mixture (hexane + decane, hexane + cyclohexane, hexane + methylbenzene, methylbenzene + decane, methylbenzene + cyclohexane and methylbenzene + tetrachloroethene) + NaCl aqueous solution were studied using the ε–β fishlike phase diagram method. The synergism in the solubilization ability was observed in the microemulsion systems containing mixtures of methylbenzene + hexane, methylbenzene + cyclohexane, and methylbenzene + tetrachloroethene, respectively. The solubility of the alcohol in the oil and aqueous phases and the composition of the interfacial layer in the microemulsion systems containing oil mixtures were also investigated. [ABSTRACT FROM AUTHOR]

An α- ε- β fish-like phase diagram of three phase microemulsions was proposed and used to investigate the phase behavior of the microemulsion systems sodium dodecyl sulfate (SDS)/alcohol/oil/water at various oil/water ratios. Related physicochemical properties of the microemulsion systems were calculated. As the oil/water mass ratio increases, the solubility ( ε) of the alcohol increases, while both the mass fraction of alcohol in the interfacial layer ( A) and the solubilization ability ( SP) decrease. The effect of oils on the properties of the microemulsion systems was investigated. [ABSTRACT FROM AUTHOR]

Phase behaviors and related physicochemical properties of the microemulsion systems containing hexadecyltrimethylammonium bromide alcohol alkane brine were studied at various alkane/water volume ratios. The alcohol solubility (εB) increases proportionally to the alkane/water ratio. Concurrently, the alcohol mass fraction in the interfacial layer (AS) increases, and the solubilization ability (SP*) of the system decreases. When the length of the carbon chain of the alkane molecules increases, the solubility of alcohol in the water and oil phases and the mass fraction of alcohol in the interfacial layer increase, while the solubilization ability of the microemulsion systems decreases. [ABSTRACT FROM AUTHOR]

The composition and the solubilization ability of the microemulsion systems containing mixed surfactants of alkyl polyglucoside (APG) and hexadecyl-trimethyl-ammonium bromide (CTAB) were studied by using the ε∼β fishlike phase diagram method. Synergistic effect in terms of the composition of the interfacial layer and the solubilization ability was observed in microemulsion systems APG + CTAB + alcohol + alkane + NaCl aqueous solution. In the interfacial layer of the microemulsions the number of surfactant molecules notably decreases, resulting in the significant improvement in the solubilization ability of the system. The effects of the carbon chain length of the alkanes and salinity on the ε∼β fishlike phase diagrams of APG (CTAB) + alcohol + alkane + NaCl solution microemulsion systems were also discussed. [ABSTRACT FROM AUTHOR]

Because of the large-scale recycling of volatile chlorine from the interior to the surface of the Earth, it is possible to use the isotopic composition of this element (δ37Cl) in serpentinite to study mantle-crust interactions in subduction zones. It is also possible to use chlorine isotopes to track the evolution of fluids (through fluid inclusions/minerals) in hydrothermal ore-forming systems. Here, we report the results of a study of equilibrium chlorine isotope fractionation during serpentinization and hydrothermal mineralization based on density functional theory (DFT) and ab initio molecular dynamics simulations (AIMD). The chlorine isotope fractionation between lizardite and brine under variable thermodynamic conditions is described by the relationship 1000lnα lizardite-fluid = 0.4170 × (1000/T)2–0.0281 × (1000/T) + 0.0582, which yielded Δ37Cl lizardite-fluid values of +0.49 to +4.46‰, +0.41 to +0.59‰ and + 0.49 to +3.57‰ for conditions at the seafloor, in the mantle wedge and in subduction zones. As a proxy for the diversity of metal-chloride complexes in hydrothermal fluids, the stable configurations of ferrous chloride complexes were acquired from long trajectories of AIMD simulation. Using this information, the chlorine isotope fractionation between minerals (i.e., apatite-group minerals, muscovite, phlogopite, tremolite, lizardite, marialite and metal halides) and ore-forming fluid was estimated. The relatively large chlorine isotope fractionation (Δ37Cl minerals-hydrothermal fluid values from −1.99 to +2.18‰) might partly explain the large variation of δ37Cl in individual fluid inclusions observed in hydrothermal ore deposits. Because of the limited chlorine isotope fractionation between apatite and hydrothermal fluid (i.e., Δ37Cl apatite-ore-forming fluid of 0.06‰–0.69‰), apatite-group minerals might be an alternative to fluid inclusions for constraining the origin and evolution of hydrothermal fluids using δ37Cl values. The theoretical constraints provided in this paper will facilitate the use of chlorine isotopes in tracking the sources of chloride in subduction zones and the origin of mineralizing fluids in ore deposits. [ABSTRACT FROM AUTHOR]

Abstract: The coefficient of thermal expansion (CTE) is one of the critical design parameters for the application of materials in cryogenic engineering and study of available results demonstrates that thin films have different properties from their bulk counterparts. However, few universal techniques have been developed to measure the CTE of thin films at cryogenic temperatures. Furthermore, the possible effect of the applied stress levels on CTE testing results has not received enough attention. In this study, two novel testing methods, one direct and the other indirect, for determining the CTE of thin films under different applied stress levels at cryogenic temperatures are proposed. The test temperature is from room temperature to 77K and a lower temperature could be reached. Advantages of the two methods are also discussed. [Copyright &y& Elsevier]

In this paper, the fishlike phase diagrams for the quaternary system of alkyl polyglucoside (APG: C8/10Gj or C12/14Gj)/alcohol/alkane/water mixtures have been studied. By using the simple mass balance equation and the HLB plane equation, some important parameters were calculated, such as the coordinates of the start point B and the end point E of the three-phase region, the mass fraction of alcohol in the hydrophile–lipophile balanced interfacial layer, AS, and the mass fractions of APG and alcohol in the interfacial layer (CS and CA). The effects of different alcohols and oils on the phase diagram and on the composition of the interfacial layer were also investigated. The shorter the carbon chain length of the oils and the longer the carbon chain length of the alcohols used in the systems, the higher the solubilization of the microemulsions. [Copyright &y& Elsevier]

The processes that caused the heterogeneity of δ37Cl in the Earth's mantle are unclear. Here we report theoretical estimates of equilibrium chlorine isotope fractionation among common chlorine-bearing minerals, namely apatite-group minerals (Cl-Ap, F-Cl-Ap, OH-Cl-Ap), muscovite, phlogopite, tremolite, lizardite, marialite and metal halides, based on first-principles calculations, and use them to provide an explanation for this heterogeneity. Our results show that at ambient P-T conditions, the reduced isotopic partition function ratio (β-factor) is strongly correlated with the metal-Cl bond length/bond strength of the above minerals and that phlogopite and muscovite are more enriched in 37Cl than other minerals. As a result of a number of factors, including the adjacent atomic environment, the sites occupied by chlorine atoms in crystals, the Cl-metal coordination and the crystal density, the sensitivity of 103lnβ to pressure follows the sequence: halite > fluoro-chlorapatite > chlorapatite > marialite > hydroxyl-chlorapatite > lizardite > tremolite > muscovite > phlogopite. Estimates of the chlorine isotope fractionation between chlorine-bearing minerals and aqueous fluid at the pressure and temperature prevailing during subduction indicate that the δ37Cl values of mantle minerals could vary between −6‰ and + 3‰, assuming equilibrium. In contrast, the average δ37Cl value of the bulk mantle is −0.53 ± 0.16‰. Thus, large-scale recycling of volatile Cl from the deep mantle to the continental/oceanic crust and ocean, and the isotopic fractionation of chlorine with increasing metamorphic grade during subduction, could explain the heterogeneity of δ37Cl values observed in mantle materials. [ABSTRACT FROM AUTHOR]

The high mobility of boron during fluid-rock interaction makes it an effective tracer for the sources of magmatic and metamorphic fluids, as recorded in minerals such as tourmaline and muscovite. Although advances have been made in quantifying the fractionation of boron isotopes among different phases, boron isotope fractionation in complex silicate melts remains poorly understood. Here, we propose appropriate models for the BO 3 and BO 4 units in silicate melts covering a wide range of chemical compositions and boron coordination structures in silicate magmas, and report the results of a theoretical investigation of boron isotope fractionation among silicate melt, minerals and fluids using a first principles theoretical approach. A comparison of measured and calculated α factors in mineral-melt and fluid-melt systems shows good agreement, suggesting the applicability of a simplified treatment of boron coordination structures in silicate melt. The results of this study show that the proportion of trigonal/tetrahedral coordinated boron and the B/Si ordering in silicate tetrahedral layers control the boron isotope fractionation among different phases, and that the effect of chemical composition is minor (less than 2‰ at 600 K). The temperature-dependent boron isotope fractionations are described as 1000lnα mica-basic fluid = 0.8–2.4 × (1000/T) - 0.8 × (1000/T)2, 1000lnα mica-acidic fluid = 7.0–14.0 × (1000/T) - 1.2 × (1000/T)2 and 1000lnα mica-tur = 1.9–5.4 × (1000/T) -3.4 × (1000/T)2 (T is temperature in Kelvins). At magmatic temperatures, ∆11B values between mineral/fluid and melt also vary with the proportion of the BO 4 unit in the melt. This study underpins the applicability of the white mica-tourmaline geothermometers and boron isotopes for fluid source identification, and also offers an explanation of boron isotope fractionation in systems that contain complex silicate melts. Unlabelled Image [ABSTRACT FROM AUTHOR]

The equilibrium boron isotope fractionations (α 3 – 4, Δ11B (Tur-fluid)) between tourmaline mineral groups and fluids at 0.5 GPa, 600–1000 K are investigated using density functional theory calculations. The first solvent shell controls boron isotope fractionation in solution, where the β values of both H 3 BO 3 and B(OH) 4 − decrease with increasing numbers of hydrogen bonds. In supercritical fluids, the weakening of hydrogen bonds and the diversity in configurations of hydrated boron species both contribute to variations in the vibrational frequencies. The 1000lnα Tur-fluid value increases with increasing Mg/(Fe+Mg) ratios in the dravite-schorl solid solution series. This effect, together with the crystallization sequence predicted from the Gibbs free energies of tourmaline formation, accounts well for the association of boron isotope and chemical zonation observed in zoned tourmaline grains. The dependence of boron isotope fractionation on the B O bond length in tourmaline group minerals reflects the changes in relevant molar volumes caused by differences in the mass and charge of the atoms occupying the X , Y , and Z sites of tourmalines. This study suggests that the chemical composition of the tourmaline plays an important role in controlling the boron isotope composition in tourmalines crystallized from hydrothermal systems. Unlabelled Image [ABSTRACT FROM AUTHOR]