Rb Concentrations Research Articles

Site environment type – The main factor of urban road dust toxicity?

The main objective of the study was to determine the effects of the water extracts of urban road dust (URD) samples on the growth inhibition and mortality rate of Heterocypris incongruens in various site environment type. We collected 24 samples of the road dust close to highways, main roads, crossroads as well as at other places i.e. residential area, and suburbs. We determined the selected metals (Al, As, Ba, Cd, Co, Cr, Cu, Ga, Mg, Mn, Mo, Ni, Pb, Rb, Sr, Ti, Tl, V and Zn) content of the water extracts of these samples as well as we tested the toxicity of the water extracts of URD samples using a commercial test Ostracodtoxkit F. We observed the lowest values of the growth inhibition of H. incongruens for residential areas and suburbs (<50%). The highest growth inhibition we found for water extracts of URD samples collected at the main roads in the Katowice urban area and crossroads in the urban areas. Although the mortality and growth inhibition of H. incongruens were related to the road traffic emissions it was impossible to clearly relate this finding with the urban site category.

Multi-elemental Analysis and Health Risk Assessment of Commercial Yerba Mate from Brazil

Consumption of yerba mate occurs mostly in the form of hot infusion (chimarrão). Water solubility of elements found in commercialized yerba mate is needed to establish nutritional value and risks associated with potentially toxic elements. In this study, yerba mate products marketed in three Brazilian states (Paraná, Santa Catarina, and Rio Grande do Sul) for chimarrão were analyzed. Total (dry product) and hot water-soluble concentrations of Al, As, B, Ba, Ca, Cd, Co, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Ni, P, Pb, Rb, S, Se, Sr, Ti, V, and Zn were determined by inductively coupled plasma mass spectroscopy (ICP-MS). Total concentrations of the ten top elements followed the order of K>Ca>Mg>Mn>P>S>Al>Fe>Ba>Zn. The most soluble elements were B, Cs, Ni, Rb, and K, with values greater than 80%. The lowest water-soluble elements were V, Fe, and Ti (values <10%), followed by Ba, Cd, Al, As, Sr, Ca, and Pb with solubility between 10 and 20%. Although total Cd levels in yerba mate products were often above those permitted by South America legislation, estimated daily consumption intake indicated no risk associated with the chimarrão beverage. Manganese was the micronutrient with the highest total and soluble levels in yerba mate, which surpassed recommended daily intake values when considering a consumption amount of 50 g day-1 of yerba mate as chimarrão. The consumption of yerba mate is safe and contributes to intake of nutrients. The Cd and Pb reference values of yerba mate products sold in South America should be revised.

Lithiation of white button mushrooms (Agaricus bisporus) using lithium-fortified substrate: effect of fortification levels on Li uptake and on other trace elements

High doses of lithium salts are used for the treatment or prevention of episodes of mania in bipolar disorder, but the medication is rapidly excreted and also shows side effects. Li may also be beneficial in people with mood disorders. Nutritionally, popular foods such as wild and cultivated mushrooms have low Li contents. This study evaluated the Li enrichment of white Agaricus bisporus mushrooms using Li2CO3 solutions to fortify the commercial growing substrate at various concentrations from 1.0 to 500 mg kg−1 dry weight (dw). Fortification of up to 100 mg kg−1 dw resulted in a significant (p < 0.01) dose-dependent increase in the accumulation of Li in mushroom, but the highest fortification level was found to be detrimental to fruitification. The median values of Li in fortified mushrooms corresponded to the fortification levels, increasing from 0.49 to 17 mg kg−1 dw relative to the background concentration of 0.056 mg kg−1 dw (control substrate contained 0.10 mg kg−1 dw). The potential for Li uptake in fruiting bodies was found to decrease at higher levels of fortification, with saturation occurring at 100 mg kg−1. Resulting lithiated mushrooms were up to 300-fold richer in Li content than specimens grown on control substrate. The fortification showed some effects on the uptake of other trace minerals, but concentrations of co-accumulated Ag, Al, As, Ba, Cd, Co, Cr, Cs, Cu, Hg, Mn, Ni, Pb, Rb, Sr, Tl, U, V and Zn were similar or lower than values reported in the literature for commercial A. bisporus. These lithiated mushrooms could be considered as a pro-medicinal alternative to treatments that use Li salts.Graphical abstract

Generation of Cretaceous high-silica granite by complementary crystal accumulation and silicic melt extraction in the coastal region of southeastern China

Abstract It is generally hypothesized that high-silica (SiO2 &amp;gt; 75 wt%) granite (HSG) originates from crystal fractionation in the shallow crust. Yet, identifying the complementary cumulate residue of HSG within plutons remains difficult. In this work, we examine the genetic links between the porphyritic monzogranite and HSG (including porphyritic granite, monzogranite, and alkali feldspar granite) from the coastal area of southeastern China using detailed zircon U-Pb ages, trace elements, Hf-O isotopes, and whole-rock geochemistry and Nd-Hf isotopic compositions. Zircon U-Pb ages indicate that the porphyritic monzogranite and HSG are coeval (ca. 96–99 Ma). The HSG and porphyritic monzogranite have similar formation ages within analytic error, identical mineral assemblages, similar Nd-Hf isotopic compositions, and consistent variations in their zircon compositions (i.e., Eu/Eu*, Zr/Hf, and Sm/Yb), which suggests that their parental magma came from a common silicic magma reservoir and that the lithological differences are the result of melt extraction processes. The porphyritic monzogranite has relatively high SiO2 (70.0–73.4 wt%), Ba (718–1070 ppm), and Sr (493–657 ppm) contents, low K2O and Rb concentrations and low Rb/Sr ratios (0.1–0.2), and it displays weak Eu anomalies (Eu/Eu* = 0.57–0.90). Together with the petrographic features of the porphyritic monzogranite, these geochemical variations indicate that the porphyritic monzongranite is the residual silicic cumulate of the crystal mush column. The HSG (SiO2 = 75.0–78.4) has variable Rb/Sr ratios (2–490) and very low Sr (1–109 ppm) and Ba (9–323 ppm) contents. Zircon from the HSG and porphyritic monzogranite overlap in Eu/Eu*, Zr/Hf, and Sm/Yb ratios and Hf contents; however, some zircon from the HSG show very low Eu/Eu* (&amp;lt;0.1) and Zr/Hf ratios. These features suggest that the HSG represents the high-silica melt that was extracted from a crystal-rich mush. The injection of mantle-derived hotter mafic magma into the mush column and the exsolution of F/Cl−-enriched volatiles (or fluids) from the interstitial melt rejuvenated the pre-existing highly crystalline mush. Subsequent extraction and upward migration of silicic melt resulting from compaction of the mush column formed the HSG at shallow crustal levels, which left the complementary crystal residue solidified as porphyritic monzogranite at the bottom.

Identifying windows of susceptibility to essential elements for semen quality among 1428 healthy men screened as potential sperm donors

BackgroundEssential elements such as iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), selenium (Se), rubidium (Rb), strontium (Sr), and molybdenum (Mo) are necessary for reproductive health. However, their associations with human semen quality remain inconclusive. ObjectivesTo investigate the associations of urinary Fe, Co, Cu, Zn, Se, Rb, Sr, and Mo concentrations with semen quality in healthy men screened as potential sperm donors and identify critical windows of susceptibility. Methods1428 healthy men provided 3766 urine and 6527 semen samples, which were measured for urinary essential element concentrations and sperm quality parameters, respectively. Linear mixed models and cubic spline curves were used to evaluate associations between urinary essential elements and semen quality. Multiple informant models were used to identify potential critical windows of susceptibility. ResultsLinear mixed models and cubic spline curves showed positive dose–response relationships between urinary Zn and sperm concentration and total count and between urinary Mo and total sperm count [all False Discovery Rate (FDR) adjusted p-value for trend < 0.05]. In the multiple-element linear mixed models, the men in the highest versus lowest quartiles of urinary Zn and Mo had a higher sperm concentration of 17.5% (95% CI: 2.8%, 34.2%; p-value for trend = 0.006) and total sperm count of 18.3% (95% CI: 1.4%, 38.0%; p-value for trend = 0.027), respectively. Urinary Zn was also positively associated with total sperm count in a dose-dependent manner (p-value for trend = 0.036), though the percentile difference in total sperm count between men in the highest and lowest quartile was not statistically significant (16.4%, 95% CI: −1.7%, 37.9%). These associations appeared to be stronger when urinary Zn and Mo were measured at 0–9 days before the date of semen examination (i.e., corresponding to epididymal storage). ConclusionsHigher urinary Zn and Mo, particularly during the period of epididymal storage, were associated with greater sperm production.

Efficacy of pine needles as bioindicators of air pollution in Incheon, South Korea

This study sought to analyze the particulate matter (PM) deposited on the surface of pine needles (Pinus densiflora) and pollutants within the needles and to investigate their utility as bioindicators. First-year needles of pines native to South Korea were collected at least 2 m above the ground. A total of four sampling points were selected: two parks around an industrial complex and two urban parks. After desorbing the PM deposited on the surface of the collected needles using ultrasonic waves, the PM and needles were classified; 21 metals, including Pb, contained in each medium were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). Useful bioindicators for air-pollution monitoring among the PM deposited on the needles included Al, As, Be, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Ba, Bi, Cs, Li, Rb, Se, Sr, Tl, U, V, and Zn contents. In an analysis of elements identified in PM and needles, Al and Mn were determined to be equally useful as monitoring indicators across a wide area. Elements with high concentrations in pine needles due to PM deposition were As, Cu, Mn, Ni, Pb, Rb, and Sr. The pine needles themselves accounted for 99.95% of the combined mass of the needles and PM, with PM representing only 0.053% of the combined mass. Therefore, washing is expected to have little effect on the pollutant concentrations within the needles.

Petrogenesis of early Eocene granites and associated mafic enclaves in the Gangdese batholith, Tibet: Implications for net crustal growth in collision zones

Granitoids and related mafic microgranular enclaves (MMEs) in continental collision zones may provide crucial insights into the formation and evolution of continental crust. In this paper, we report an investigation into the mineralogy, zircon U–Pb geochronology, whole-rock major and trace elements, and Sr–Nd–Hf isotopic geochemistry of granodiorites and hosted MMEs, as well as monzogranites, from the Zhaxiding intrusive complex in the Gangdese batholith, southern Tibet. Zircon U–Pb dating suggests that these rocks were emplaced during the early Eocene (49 to 47 Ma). Field investigation and petrological observations indicate that the MMEs represent globules of a mafic magma that was injected into the host felsic magma. On the basis of depleted zircon Hf (εHf(t) values of +6.5 to +9.2) and whole-rock Sr–Nd (εNd(t) values of +1.6 to +2.6) isotopic compositions, along with their whole-rock compositions, the MMEs are interpreted as having resulted from mixing of mantle-derived magma with juvenile crust-derived melts. The granodiorites and monzogranites are metaluminous and have positive zircon εHf(t) (+6.3 to +8.9 for granodiorites and +1.7 to +10.2 for monzogranites) and whole-rock εNd(t) (+1.6 to +1.9 for granodiorites and +0.5 to +1.1 for monzogranites) values. The granodiorites further exhibit continental crust-like chemical compositions (e.g., enrichment in Rb, K, and Pb and depletion in Nb and Ta) and high Mg# values, suggesting that they originated from partial melting of juvenile crust with the involvement of mantle-derived melts. However, the monzogranites have lower P, Ti, and total rare earth element contents, similar Rb, Ba, and Sr contents, and uniform Eu anomalies compared with the granodiorites, and were likely generated by fractional crystallization of amphibole and Fe–Ti oxides from juvenile crust-derived magma. We propose that underplating of mantle-derived magma likely triggered coeval crustal magmatism and that mixing of the mantle- and crust-derived magmas and subsequent crystallization differentiation formed the intermediate to felsic Zhaxiding intrusive complex in the Gangdese batholith. The continental crust-like bulk compositions of the intermediate to felsic magmatic rocks represent a net addition of juvenile material to continental crust. Our study thus indicates that magma mixing and differentiation play a significant role in the formation of andesitic to dacitic continental crust in collision zones.

Composite grains from volcanic terranes: Internal dose rates of supposed ‘potassium-rich’ feldspar grains used for optical dating at Liang Bua, Indonesia

In optical dating of feldspars, it is commonly supposed that potassium (K)-rich feldspar grains have been isolated for luminescence measurements by means of density separation. The K and rubidium (Rb) concentrations of these grains deliver a significant internal beta dose rate. K and Rb concentrations of 12.5 ± 0.5 wt% and 400 ± 100 ppm, respectively, are typically assumed for dose rate and age calculation, but this assumption may be wrong. Thorium (Th) and uranium (U) also contribute to the beta and alpha components of the internal dose rate. We investigated the K, Rb, Th and U concentrations of individual luminescent feldspar grains in four sediment samples from Liang Bua in Indonesia to determine single-grain internal dose rates and appropriate sample-average internal dose rates. The composition of the ‘K-rich’ feldspar fraction was investigated using X-ray diffraction spectrometry (XRD), which found that this fraction was heavily contaminated in each sample by quartz and plagioclase feldspars. Grains with detectable post-infrared infrared stimulated luminescence (pIRIR) signals were characterised using a range of techniques, including energy-dispersive spectroscopy (EDS), wavelength-dispersive spectroscopy (WDS) and quantitative evaluation of minerals using EDS (QEM-EDS). The grains were found to be composed of a range of minerals, including feldspars, quartz, clay minerals and heavy minerals, as well as volcanic glass. The K concentrations of these composite grains were determined using QEM-EDS, and their Rb, Th and U concentrations were determined using laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS). The calculated internal dose rates were very low for the majority of grains in each sample (<0.2 Gy.ka−1 for 180–212 μm-diameter grains), although a wide spread of internal dose rates was also observed. None of the samples showed any relationship between internal dose rate and either pIRIR signal intensity or equivalent dose (De). Two samples of clastic sediment were found to have different distributions of internal dose rate to those of two samples of tephra. To obtain reliable ages for sediment samples from Liang Bua thus requires the use of appropriate whole-of-grain and sample-average internal dose rates for grains with composite mineralogies deposited in these contrasting sedimentary contexts. More generally, greater consideration needs to be given to the internal dose rates of feldspar grains in volcanic regions such as Island Southeast Asia, especially composite grains with complex mineralogies, to ensure that the calculated ages are accurate.

Color as a New Proxy Technique for the Identification of Road Dust Samples Contaminated with Potentially Toxic Elements: The Case of Mérida, Yucatán, México

The design of proxy techniques is an innovative tool to monitor the potentially toxic elements of pollution in road dust. This study evaluated the use of road dust color as a proxy methodology to identify samples contaminated with presumably contaminating elements. FRX determined the concentrations of Fe, Ti, Rb, Sr, Y, Cu, Zn, and Pb in eighty-five road dust samples. The appliance of the RGB system and the Munsell color cards identified five color groups of road dust samples. The discriminant analysis validated these groups by colorimetric indices and presumably contaminating elements. The “very dark gray” color of road dust contains the highest concentrations of Pb, Cu, Zn, and Y. The redness and saturation rates showed high correlations with presumably contaminating elements in “dark gray” and “very dark gray” color samples. The color of road dust, as a proxy technique, allows identifying samples contaminated with presumably contaminating elements.

Granite geochemistry is not diagnostic of the role of water in the source

The diverse fluid regimes during melting of the metasedimentary crust have been often discriminated on the basis of the composition of anatectic granitoids, with granites indicating fluid-absent melting conditions and trondhjemitic compositions suggesting the addition of external water in the source region. The lack of abundant metasedimentary-derived trondhjemites in the geological record is supposed to prove the minor role of water-fluxed melting in the crustal maturation. In terms of trace elements, instead, Rb, Sr and Ba contents and their ratios have been commonly used to discriminate dehydration vs. water-fluxed melting scenarios. Here I show that reconciling results of melting experiments, thermodynamic modeling and nanogranitoid study brings out a different picture. Equilibrium thermodynamics cannot properly reproduce melt compositions of the selected benchmark experiments, with the latter having trondhjemitic compositions mainly for the metastable behavior of muscovite during laboratory runs. The formation of sufficient volumes of extractable trondhjemitic melts is related to high pressure melting conditions (≥8 kbar at 700°C and ≥11 kbar at 750°C) or K-poor bulk rock compositions, rather than to the only presence of water. At low- to medium-pressure, crustal melts are granites in composition, whatever the fluid regime is. It is inferred that the abundance of anatectic peraluminous granites (compared to metasedimentary-derived trondhjemites) does not imply a dry nature of the orogenic crust. Likewise, the use of LILE (Rb, Sr and Ba) signatures may lead to erroneous conclusions on the fluid regime of the deep continental crust.

Hypogene kaolin deposits from felsic intrusive rocks (Peninsular Malaysia) with special reference to rare earth elements and stable isotopes geochemistry

Clay fractions of the hypogene kaolin deposits from Ipoh granite and Jerai pegmatite are composed of kaolinite, while the greenish kaolin horizon of Ipoh area comprises of illite and kaolinite. Al2O3 and SiO2 are the main constituents in the studied kaolins with very low concentrations of other oxides. K2O occurs in relatively high contents in the illite-rich kaolin that formed by hydrothermal alteration of biotite-granite of the greenish kaolin horizon of Ipoh area. The higher contents of Ba, Cr, Cs, Ga, Rb, Sc, and Sn in the illite-rich horizon are inherited from its source rock. The relative enrichment of light rare earth elements (LREE) over heavy rare earth elements (HREE) as indicated from the high (La/Yb)n ratios and positive correlations between ΣREE and P2O5 in the studied kaolins suggest the occurrence of REE as authigenic florencite, churchite and/or rhabdophane and, therefore, reflect the kaolinitization process rather than the parent rocks. δH and δO values are similar in both Ipoh and Jerai kaolins with dH values range from −84 to −99‰ and positive δO values varying between 0.95 and 5.47%. H- and O-isotopes data fall close to the left side of the kaolinite line in equilibrium with meteoric water at temperatures of > 100 °C. The pronounced negative Eu anomalies, absence of positive Ce anomaly and high crystallization temperature (94–113 °C) indicate the hydrothermal (hypogene) origin of the studied kaolins as a result of the Triassic post-magmatic hydrothermal activities in Peninsular Malaysia. Mineralogical and geochemical variations among the studied deposits although they formed by the same kaolinitization process, suggest a significant role of parent rocks in their compositions.

A Quantitative Comparison of Heavy Metal Concentrations in the Soils on Two Rocky Mountain West tribal Reservations

Native Americans have experienced a long history of environmental injustice, including natural resource exploitation and commercial activity with environmental impacts. A community-based participatory research (CBPR) approach was used to partner with two Rocky Mountain West reservations to conduct pilot-level assessments of potential soil contamination by heavy metals. The Community Advisory Board in conjunction with the research team selected residential areas and community sites for sampling. Samples were obtained, transported to a laboratory for dehydration and sieving, and were analyzed with a handheld X-ray fluorescence (XRF) tool for the presence of 24 heavy metals. Heavy metals concentrations were compared between reservations and were found to be statistically different from one another. Findings were also compared to levels recommended by the Environmental Protection Agency (EPA) and World Health Organization (WHO) to determine possible hazards to human health. Concentration of Sr, Rb, and Th were well above acceptable EPA levels and require further analysis. High localized Pb levels were found in one area, while Hg levels were found close to EPA standards. CBPR was essential to understanding preliminary contamination patterns. In conclusion, even reservations with similar geographies and histories present with unique contaminations and require individualized study to determine possible environmental mitigation.

Source of 226Ra in Ramsar spring water, Iran: implication of water–rock interaction and stable isotopes

This study was carried out primarily to understand the hydrogeochemical processes controlling the 226Ra anomalies in Ramsar area. Analyses revealed two types of water: (1) non-thermal Ca–HCO3 type and (2) thermal Na–Cl type, mainly of meteoric and hydrothermal origin, respectively. Non-thermal springs have higher concentrations of U due to silicate weathering. Thermal springs are characterized by high concentrations of 226Ra, As, Fe, Li, Cs, Rb, Sr, Ba, B, Br−, F−, NO3−, PO43− and SiO2 resulting from high-temperature water–rossck interaction and mixing with hydrothermal fluids. Thermal springs are manifestations of an old hydrothermal system with subsurface reservoir temperatures varying between 83 and 100 °C. Radium activity is negatively correlated with pH and positively correlated with TDS, Cl−, Ba, and Ca, reflecting competitive ion effects of alkaline-earth metals, complexing with Cl−, and co-precipitation with barite and calcite. These processes are thought to be the dominant factors in controlling 226Ra mobility in spring water.

Health risk assessment of Macro, Trace-elements and heavy metal in various Indian Antidiabetic Polyherbal formulations.

Diabetes mellitus, a global pandemic, can be holistically managed with the use of polyherbal formulations which is an accessible form of treatment in developing countries due to fewer side effects, economical and easily available. Commercial polyherbal formulation lacks systemic based scientific study, thus it is suspected to be associated with many contaminations and related toxicities, one of which is considered to be elemental health hazards. Therefore, the present study is designed to assess six selected antidiabetic polyherbal formulations from the Indian market for their element contents, quality, and health risk assessment. Concentrations of 35 essential and non-essential trace-elements were quantified by Handheld X-ray spectrophotometer and health risk assessment was calculated by estimated daily intake (EDI) and Total hazard quotient (THQ). Elements were found to be in a vast range of concentration in the tested APH. Among the 35 elements analyzed, Ca (23100±0.033ppm) and K (14800±0.021 ppm) in "MH" and Zn (15600±0.025 ppm) in "DB" were found to be the highest. The lowest concentrations of Rb and Nb (3±2 ppm) were observed in the formulation "MH" and "SN" respectively. THQ of all the elements was calculated to be less than unity except for Rb in the formulation "MA". Rb is rarely associated with toxicities as it is rapidly excreted in sweat and urine. V, Co, Ni, Cu, As, Se, Y, Ag, Sn, Sb, Ba, W, and Hg were absent in all the APH. Therefore the present study indicated the presence of essential elements some of which are important for the management of diabetes and hence can be considered safe for use.

Geochronology, geochemistry and mineral chemistry of Malayer–Boroujerd–Shazand pegmatite dikes, Sanandaj–Sirjan zone, NW Iran

Pegmatite dikes in the Malayer–Boroujerd–Shazand magmatic complex, located in the Sanandaj-Sirjan zone of the Zagros orogen, are hosted in both granitoid rocks and their contact and regional metamorphic aureoles. In this study, we report the geochronology, geochemistry and mineral chemistry of these pegmatite dikes. The granitoid rocks in the Malayer–Boroujerd–Shazand magmatic suites are mainly monzogranite, quartz diorite, granodiorite and quartz monzonite characterized by metaluminous to peraluminous I-type compositions of the calc-alkaline series and display the geochemical characteristics of volcanic arc granites related to an active continental margin. The pegmatite dikes mainly consist of quartz, feldspar (albite and orthoclase), tourmaline, muscovite and less common biotite and garnet. The tourmaline content in the igneous-hosted pegmatite dikes is higher than those of metamorphic rocks, whereas the muscovite content is lower in the igneous-hosted pegmatite dikes. The K/Rb ratio and the Rb content of pegmatite dikes and their minerals (K-feldspar and muscovite) indicate that they are less evolved. Pegmatite dikes display a typical calc-alkaline affinity of I-type granites and are classified as peraluminous Lithium-Caesium-Tantalum (LCT) family (barren sub-type) to muscovite class. The tourmaline is a schorl-foitite type, which is common in the early crystallization stage of less evolved pegmatites. U–Pb zircon dating of the Boroujerd and Shazand pegmatite dikes yield weighted mean 206Pb/238U ages of 160.2 ± 1.8 and 121.8 ± 1.5 Ma, respectively. In contrast, U–Pb zircon dating of the Malayer pegmatite dike gives a mean 206Pb/238U age of 43.2 ± 1.5 Ma. Our new geochronological data indicate that the first group of pegmatite dikes (older pegmatite dikes) in the Boroujerd district (160.2 ± 1.8 Ma) shows an overlap with the main and first magmatic episode in the Sanandaj–Sirjan zone during Jurassic times, simultaneous with the Middle Cimmerian Orogenic phase, and formed during the subduction initiation. The second group of pegmatite dikes in the Shazand district (121.8 ± 1.5 Ma) formed in the Early Cretaceous and shows a temporal overlap with previously reported ages (ca. 130–114 Ma) during the early Alpine tectonic movements (Late Cimmerian Orogenic phase). Finally, the younger group of pegmatite dikes in the Malayer district (43.2 ± 1.5 Ma) formed in the Eocene overlapping with previously reported ages (ca. 34–52 Ma) which is equivalent to the Laramian phase. These data reveal that the magmatism in the Malayer–Boroujerd–Shazand magmatic complex started in the Early-Middle Jurassic resembling adjacent areas in the Sanandaj–Sirjan zone (e.g., Hamedan region) by melting of crustal protoliths in a subduction tectonic setting. The second and third groups of pegmatite dikes formed during the late subduction to syn-collisional process, respectively. These pegmatite generation marked the subduction initiation to syn-collisional span in the region. The zircon geochemistry (negative Ce anomalies and positive Eu anomalies) is indicative of the relatively oxidized conditions of the parent magma and shows characteristics of continental crust zircon.

A Rayleigh model of cesium fractionation in granite-pegmatite systems

Abstract The K/Cs ratios of K-feldspars from granitic pegmatites are compared to models derived from the Rayleigh equation. The K/Cs and K/Rb ratios of K-feldspars and micas exhibit decreasing values when plotted against their Cs or Rb contents across cogenetic suites of granites and pegmatites and from margin to core of individual bodies. The trends in elemental ratios conform to Rayleigh fractionation for the crystallization of feldspars and micas from a silicate melt. Within two individual pegmatite bodies, the K/Cs ratio of K-feldspar initially falls more rapidly than the Rayleigh model predicts. That might reflect a local increase in the concentration of Cs relative to K due to the pile-up of incompatible elements in a boundary layer of melt adjacent to the crystal growth front. The addition of an aqueous solution to the Rayleigh model (i.e., the simultaneous crystallization of K-feldspars from melt and from aqueous solution) predicts high and increasing K/Cs ratios of K-feldspars that are not observed in natural rock suites, except when K-feldspars crystallize in miarolitic cavities or when primary K-feldspar recrystallizes to microcline perthite in an open hydrothermal system. In those cases, the Cs content of K-feldspars falls to nil because of the high solubility of Cs in aqueous solution and low compatibility of Cs in K-feldspar. Otherwise, the observed patterns of K/Rb or K/Cs in K-feldspar and micas in pegmatites conform to crystal-melt fractionation in which an aqueous solution plays no part. From the viewpoint of the geochemistry of Cs in pegmatites, these observations give support to the model proposed by Cameron et al. (1949) and endorsed by Jahns (1953a, 1953b).

Tungsten mineralization during the evolution of a magmatic-hydrothermal system: Mineralogical evidence from the Xihuashan rare-metal granite in South China

Abstract Tungsten deposits are usually associated with granitic intrusions that record a long and complex evolution of the magmatic-hydrothermal system. However, the genetic link between magmatic-hydrothermal evolution and tungsten mineralization remains unclear. The Xihuashan tungsten deposit in South China, an important vein-type wolframite deposit, is closely associated with greisen and multi-phase intrusive activity that produced biotite granite, two-mica granite, and muscovite granite. From the biotite granite to the two-mica granite to the muscovite granite, micas vary from siderophyllite to lithian siderophyllite, with decreasing K/Rb and Nb/Ta ratios and increasing Rb and Cs contents. The zoned micas in the muscovite granite and greisen display fluorine-depleted rims, reflecting subsolidus replacement by external aqueous fluids. The presence of siderite indicates a Fe-, Mn-, and CO2-rich fluid under reducing conditions. The micas in the greisen have higher-F contents and lower Fe3+/Fe2+ ratios than those in the muscovite granite, suggesting that the fluids contributing to greisen formation had a relatively high-fluorine content and were reduced. The increase of CO2 in the fluid enhanced its ability to unlock W from melts/rocks into fluids. The reducing environment also facilitated the tungsten mineralization. During greisenization, the pH value of the fluid increased, which destabilized the polymeric tungstates to form WO42–. The mixture of W-rich solution and Fe-, Mn-rich external fluid eventually precipitated as vein-type wolframite in favorable locations. An empirical equation (Li2O = 0.0748 × F2 + 0.0893 × F) was introduced for estimating the Li2O contents of hydrothermal micas using the F contents determined by EPMA.

Effect of moxibustion on acupoints at "opening" time on telomere length and expression of liver cell cycle regulators in aging rats

To observe the effects of "lingguibafa" moxibustion performing at the appropriate acupoints at their "opening" time on telomere length，expressions of p53 of tumor supressor genes and retinoblastoma gene(Rb)in the liver of aging rats，so as to explore its mechanisms underlying delaying senescence. Forty male SD rats were randomly divi-ded into normal, model, prevention and treatment groups, with 10 rats in each group. The rat model was established by intrape-ritoneally injection of D-galactose (200 mg/kg) once a day for 42 days. The rats in the prevention group were given "lingguibafa" moxibustion during modeling, while those in the treatment group were given "lingguibafa" moxibustion after modeling. Quantitative real-time PCR was used to detect the telomere length and the mRNA expressions of p53 and Rb，ELISA was used to detect the protein contents of p53 and Rb in the liver tissues. Compared with the normal group, the relative telomere length of the model group was significantly shortened (P<0.01), the mRNA expressions and protein contents of p53 and Rb were significantly increased (P<0.01). After intervention and in comparison with the model group, the relative telomere length of the prevention group and the treatments group were significantly increased (P<0.01), and the expressions of p53 and Rb mRNA and protein contents were significantly reduced (P<0.01, P<0.05). There were no significant difference between the prevention and the treatment groups in the abovementioned indexes (P>0.05). Moxibustion on acupoints at "opening" time can inhibit the shortening of telomere length and the down-regulation of the expressions of p53 and Rb in aging rats, which may contribute to its function in delaying the process of cell senescence.

Environment-friendly synthesis of Ni0.5Zn0.5Fe2O4 magnetic nanoparticles using Plantago major and its applications as an efficient and rapid adsorbent for removal of reactive blue 21 dye

ABSTRACT The Ni0.5Zn0.5Fe2O4 magnetic nanoparticles (MNPs) were synthesised using Plantago major seed extract through an environment-friendly, economic, and easy procedure. The nanoparticles were characterised by FTIR, XRD, SEM, TEM, EDX, BET surface area analysis, and VSM. The Ni0.5Zn0.5Fe2O4 MNPs were investigated as a nanoadsorbent for removal of reactive blue 21 (RB 21) and the results showed that the nanoparticles were effective for adsorption of RB 21. More than 93% of RB 21 was removed by the nanoadsorbent after a short time of 10 min (60 mg of nanoadsorbent dosage at concentration of 20 ppm for RB 21). The effect of initial concentration of RB 21 and nanoparticle dosage on dye adsorption were investigated. The Langmuir and Freundlich isotherm models used for adsorption equilibrium of RB 21 on Ni0.5Zn0.5Fe2O4 MNPs. The isotherm studies showed that the Langmuir model (KL = 2.76 L/mg, qmax = 18.08 mg/g) provides more compatible than the Freundlich model and thus RB 21 adsorb on the surface of Ni0.5Zn0.5Fe2O4 MNPs by a mono layer adsorption. The adsorption kinetics studies for the adsorption of RB 21 on Ni0.5Zn0.5Fe2O4 MNPs were conducted using the pseudo first-order, the pseudo second-order, and the intraparticle diffusion models and the results indicated that the pseudo second-order model (qe = 15.19 mg/g) provides more compatible than the other models for the adsorption of RB 21 on Ni0.5Zn0.5Fe2O4 MNPs. The maximum adsorption capacity was determined as 16.65 mg/g.

RETRACTED ARTICLE: Rb(I)/Se(IV) co-dopant into hydroxyapatite; their structural, morphological, and antibacterial effectiveness for biomedical applications

Co-substituted hydroxyapatite (HAP) with cationic rubidium (Rb+) and anionic selenite ( $${\text{SeO}}_{3}^{2 - }$$ ) was synthesized at different contributions of Rb+ ions. The chemical formula of the composition is [RbxCa(10–0.5x)(PO4)5(SeO3)(OH)2], where 0 ≤ x ≤ 0.8 with step 0.2. The structure and morphology of the as-prepared compositions were investigated upon the concentration of (Rb+) ions. It was mentioned that the roughness average (Ra) starts from 26.2 nm and grows up, reaching 42.6 nm. This noticeable roughness degree due to Rb insertions is reflected in adhesive ability in the biological environment. Rubidium dopant has a significant effect on particle size that inhibits size growth. The internal porosity could be classified as micropores except at x = 0.6 and 0.8, which are considered macro-pores. Rb/Se-HAP compositions' cell viability was investigated through the human osteoblast cell line (HFB4), and the life ratio achieved around 98.1 ± 3.9%. Furthermore, the additional Rb+ ions promote antibacterial activity, whereas the inhibition zone started from 1.6 ± 0.2 and 1.3 ± 0.3 mm and grew up to 5.3 ± 0.9 and 4.9 ± 0.8 mm for x = 0.0 and 0.8, against E. coli and S. aureus, respectively. Thus, the reported stoichiometric compositions are considered to be promising materials for biomedical applications.