Experimental and numerical investigations on micromixing performance of multi-orifice cross-flow jet mixers

Multi-orifice cross-flow jet mixers(MOCJMs)are used in various industrial applications due to their excellent mixing efficiency,but few studies have focused on the micromixing performance of MOCJMs.Herein,the flow characteristics and micromixing performance inside the MOCJM were investigated using experiments and computational fluid dynamics(CFD)simulations based on the Villermaux/Dushman system and the finite-rate/modified eddy-dissipation model.The optimal A value was correlated with the characteristic parameters of MOCJMs to develop a CFD calculation method applicable to the study of the micromixing performance of the MOCJMs.Then the micromixing efficiency was evaluated using the segregation index XS,and the effects of operational and geometric parameters such as mixing flow Reynolds number(ReM),flow ratio(RF),total jet area(ST),the number of jet orifices(n),and outlet configuration on the micromixing efficiency were investigated.It was found that the intensive turbulent region generated by interactions between jets,as well as between jets and crossflows,facilitated rapid reactions.XS decreased with increasing ReM and decreasing RF.Furthermore,MOCJMs with lower ST,four jet orifices,and the narrower outlet configuration demonstrated a better micromixing efficiency.This study contributes to a deeper understanding of the micromixing performance of MOCJMs and provides valuable guidance for their design,optimization,and industrial application.

Efficient extraction of phenol from wastewater by ionic micro-emulsion method:Anionic and cationic

Phenolic wastewater is one of the priorities in the field of wastewater treatment,which poses a serious threat to the human health and nature environment.In this paper,cationic cetyltrimethylammonium bromide(CTAB)and anionic sodium oleate(Na OL)microemulsions were utilized to extract phenol from the wastewater.The optimal extraction factors were investigated by exploring the effects of microemulsion composition ratio and extraction conditions on the phenol extraction performance.Furthermore,the enhanced extraction mechanism of phenol by cations microemulsions is illustrated by studying the extraction process of cationic and anionic microemulsions in the extraction of phenol.The optimum components were obtained:surfactant concentration of 0.2 mol·L^(-1),isoamyl alcohol volume of 30%,internal aqueous phase concentration of CTAB microemulsion of 0.05 mol·L^(-1),and internal aqueous phase concentration of Na OL microemulsion of 0.09 mol·L^(-1).The extraction efficiencies were 96.44%and 82.0%when using CTAB and Na OL microemulsions under optimal conditions(water-emulsion ratio of 5,contact time of 9 min,extraction temperature of 298.15 K,and p H of 9),confirming the enhanced extraction of phenol by CTAB cationic microemulsion.It was analyzed that the enhanced extraction of CTAB microemulsion was due to the electrostatic adsorption of cations with phenol root ions.

Genesis of tuff interval and its uranium enrichment in Upper Triassic of Ordos Basin, NW China

Recently measured high gamma ray values in the Yanchang Formation of the Upper Triassic in the Ordos Basin have added an interesting and controversial twist to the study of the formation’s uranium enrichment and genesis.High uranium and thorium contents in the tuffaceous layer cause high gamma ray values in the Yanchang Formation.Petrographic studies,major elements,rare earth elements(REEs),and trace elements have been systematically analyzed to determine the composition,geochemical environment,and diagenetic processes of the layer.The observed color of the tuffaceous layer in the study area varies from yellow to yellowish brown.The tuff consists of matrix supported with sub-rounded to sub-angular lithic fragments.These lithic fragments probably derived from pre-existing rocks and incorporated into the tuffaceous layer during volcanic eruption.Quartz,plagioclase,and biotite were observed in well to poorly sorted form,in addition to framboidal pyrite and organic laminae.Measured ratios of SiO_2/Al_2O_3 ranged from 3.277 to 6.105 with an average of 3.738.The ratio of TiO_2/Al_2O_3 varied from 0.037 to 0.201 with an average of 0.061,indicating that the sediments of the tuffaceous layer originated from an intermediate magma.REE distribution patterns show sharp negative Eu anomalies,indicating a reducing environment,which is suitable for uranium deposition.A reducing environment was confirmed by black shale in the base of the Yanchang Formation.Such black shale has high organic matter content that can take kerogene from mudstone and provide a reducing environment for uranium enrichment in the tuffaceous layer.Moreover,negative Eu anomalies and the REE patterns indicate a subduction-related volcanic arc environment as the magma source of the tuffaceous layers.High values of Rb,Ba,and Sr might be the result of fluid phase activities;low values of Hf and Eu indicate the involvement of crustal material during diagenesis of the tuff.Discrimination diagrams(Th/Yb vs Ta/Yb,Th/Hf vs Ta/Hf)suggest an active continental margin as the tectonic setting of source volcanoes.Plots of Nb versus Y,Rb versus Y+Nb,TiO_2 versus Zr,and Th/Yb versus Nb/Yb of the tuffaceous content point to calc-alkaline continental arc-related magmatism.We concluded that uranium enrichment in the tuffaceous layer was supported by oxidation–reduction.

Geochemistry and geochronology of Late Jurassic and Early Cretaceous intrusions related to some Au(Sb) deposits in southern Anhui: a case study and review

Some Au deposits in southern Anhui Province have recently been found to be closely associated with Late Mesozoic intrusions. Typical examples include the Huashan Au(Sb) deposit and Au deposits at Zhaojialing, Wuxi,and Liaojia. In order to understand the mechanisms that led the formation of these Au deposits, we make detailed reviews on the geological characteristics of these Au deposits. Specifically, we present new LA-ICP-MS zircon U–Pb dating, along with elemental and Hf isotopic data from the Huashan Au(Sb) deposit. Our data suggests that the Huashan ore-related intrusions were emplaced during the Late Jurassic and Early Cretaceous periods(144–148 Ma). They are characterized by arc-magma features and high oxygen fugacity and are rich in inherited zircons. Zircon U–Pb ages and Lu–Hf isotopes from intrusions suggest that Proterozoic juvenile lithosphere is the main source of these intrusions. The regional geological history implies that lithosphere beneath southern Anhui was produced during a Proterozoic subduction and was fertilized with Au(Cu) in the process. Integrated with theresults of previous studies, we inferred that Late Mesozoic intrusions formed by the remelting of the lithosphere could provide the metal endowment for the Au-rich deposits in southern Anhui.

Geochemistry of subducted metabasites exhumed from the Mariana forearc:Implications for Pacific seamount subduction

Seamounts on the drifting oceanic crust are inevitably carried by plate motions and eventually accreted or subducted.However,the geochemical signatures of the subducted seamounts and the significance of seamount subduction are not well constrained.Hundreds of seamounts have subducted beneath the Philippine Sea Plate following the westward subduction of the Pacific Plate since the Eocene(~52 Ma).The subducted oceanic crust and seamount materials can be exhumed from the mantle depth to the seafloor in the Mariana forearc region by serpentinite mud volcanoes,providing exceptional opportunities to directly study the subducted oceanic crust and seamounts.The International Ocean Discovery Program(IODP)expedition 366 has recovered a few metamorphosed mafic clasts exhumed from the Mariana forearc serpentinite mud volcanoes,e.g.,the Fantangis?a and Asùt Tesoru seamounts.These mafic clasts have tholeiitic to alkaline affinities with distinct trace elements and Nd-Hf isotopes characteristics,suggesting different provenances and mantle sources.The tholeiites from the Fantangisna Seamount have trace element characteristics typical of mid-ocean ridge basalt.The Pacific-type Hf-Nd isotopic compositions,combined with the greenschist metamorphism of these tholeiites further suggest that they came from the subducted Pacific oceanic crust.The alkali basalts-dolerites from the Fantangisna and Asùt Tesoru seamounts show ocean island basalt(OIB)-like geochemical characteristics.The OIB-like geochemical signatures and the low-grade metamorphism of these alkali basalts-dolerites suggest they came from subducted seamounts that originally formed in an intraplate setting on the Pacific Plate.The Pacific Plate origin of these metabasites suggests they were formed in the Early Cretaceous or earlier.Two types of OIBs have been recognized from alkali metabasites,one of which is geochemically similar to the HIMU-EMI-type OIBs from the West Pacific Seamount Province,and another is similar to the EMII-type OIBs from the Samoa Island in southern Pacific,with negative Nb-Ta-Ti anomalies and enriched Nd-Hf isotopes.Generally,these alkali metabasites are sourced from the heterogeneous mantle sources that are similar to the present South Pacific Isotopic and Thermal Anomaly.This study provides direct evidence for seamount subduction in the Mariana convergent margins.We suggest seamount subduction is significant to element cycling,mantle heterogeneity,and mantle oxidation in subduction zones.

Detrital zircon U-Pb age perspective on the sediment provenance and its geological significance of sandstones in the Lamandau region, SW Borneo, Indonesia

The Southwest Borneo(SW Borneo)block belongs to Sundaland and is the oldest continental fragment of Borneo that is believed to derive from the Gondwana land.The U-Pb isotopic dating ages of 113 detrital zircons from sandstones of the Ketapang Complex in SW Borneo range from 3298 Ma to 78 Ma,and show six major age populations:2476-2344 Ma,2016-1831 Ma,1296-759 Ma,455-406 Ma,262-210 Ma,and 187-78 Ma.The youngest age of these detrital zircons is 78 Ma,indicating that the maximum depositional age of the sandstones is Campanian.Permian-Late Cretaceous detrital zircons are interpreted as having been derived from the nearby Schwaner Mountains and the Permian-Triassic tin belt granitoids in Southeast Asia(SE Asia).Archean-Carboniferous detrital zircons have a continental Gondwana provenance,with their age spectra similar to those of northwestern Australia,indicating that these zircons could be derived from the orogenic belts and cratons in northwestern and central Australia.The provenance of these detrital zircons in this study indicates the SW Borneo block was located on the northwestern margin of Australia during the Paleozoic,in the region of the Banda Embayment.SW Borneo rifted from Australia and moved northward in the Early Jurassic,and this block was added to Sundaland in the Early Cretaceous.The Luconia-Dangerous Grounds continental fragment derived from East Asia collided with SW Borneo after subduction in the Cretaceous,which induced the widespread magmatism in the Schwaner Mountains in SW Borneo.

Oil droplet movement and micro-flow characteristics during interaction process between gas bubble and oil droplet in flotation

Flotation is an efficient pre-treatment technology for oily water.In this work,the interaction process between the moving oil droplet and the gas bubble was studied by high-speed camera and Bassset-Boussinesq-Oseen(BBO)theoretical model,and the experimental and simulation results of the oil droplet trajectory were compared.Moreover,the micro-particle image velocimetry system was utilized to observe the flow inside and outside of the moving oil droplet.The results show that the BBO model with the mobile bubble’s surface can reflect the velocity change trend of the oil droplet during the interaction process between the moving oil droplet and the gas bubble,but there are some significant differences between the experimental and simulation results.While the oil droplet is moving on the bubble’s surface,the velocity of the area near the contact point of oil droplet–gas bubble is less than that of the other areas inside the oil droplet.Meanwhile,the flow of water above the oil drop is more biased towards the gas bubble.

The Uranium Prospects in Mika Region, Northeastern Nigeria

Uranium exploration especially in currently non-producing countries like Nigeria possesses high economic prospect. This study investigates a new uranium prospect in Mika, Northeastern Nigeria. The Mika uranium mineralization is located in Mika, Taraba State. Two lodes were identified and additional nine (9) trenches were added. The main lode in the west extends about 10 m, ore vein strikes 348°, inclination 42°and the strike of the lode 306°with average uranium content of 18%. The eastern trench is about 8 × 4 × 6 m which exposes a veinlet of pitchblende. From the petrography, one can deduce that the granitic host rock has suffered deformation resulting in crushing of quartz crystals and stretching of plagioclase. The uraninite and chalcedony in the late phase filled up the fractures along the crystal grain boundaries as veinlets. The laboratory gamma ray analysis of the samples showed that the secondary uranium content is 0.1%, while the primary uranium ore grade is 1.5%. Radiometric in situ measurements showed that Th and K ranges from 47.3 - 3654 ppm and 4.26% - 6.26% respectively. From the survey, a strong radiometric zone extends 800 × 35 m in an NW-SE direction and has highest radiation content of 1200 cpm against the background count rate of 30 cpm. Generally, the uranium concentrations in the ores in Mika area range from 0.03% - 0.12%. Since only the surface occurrences have been explored, the study area is a good prospect for future development when properly explored. The North-eastern Nigeria has been roughly explored by Nigeria Uranium Mining Company (NUMCO) in 1980, but no formal exploration had been followed after that, especially near the site of this article. The company (ACE Mines, Ltd) of the first author was among the few uranium mining companies approved in the list of Nigerian Geological Survey agency of Abuja in Nigeria. The authors determined the coordinates of the site in their first survey which formed the prospect area in the licence.

DETECTION AND APPLICATION OF MICROFLUIDIC ISOTHERMAL AMPLIFICATION ON CHIP

Loop-mediated isothermal amplification(LAMP)is a novel nucleic acid amplification method.Compared with the widely utilized polymerase chain reaction(PCR),LAMP has higher speed and efficiency as well as lower requirement for system temperature control because the whole amplification process is isothermal and no efforts are needed to switch between different temperatures.In this paper,we designed and fabricated different kinds of polycarbonate(PC)microfluid chips,explored appropriate reaction condition for LAMP in microenvironment(1 nL→10μL),and developed a microfluidic isothermal amplification detection system.The DNA optimal amplification temperature is obtained;the starting time of exponential amplification of DNA is put forward farther.The optimal condition of DNA amplification in microenvironment,with a little reaction materials and early starting exponential amplification time of DNA are very important for clinic DNA detection and the application of Lab-on-a-Chip.

LABEL-FREE DETECTION OF PROTEIN MICROARRAY WITH HIGH THROUGHPUT SURFACE PLASMON RESONANCE IMAGING(SPRI)

A surface plasmon resonance imaging(SPRI)system was developed for the discrimination of proteins on a gold surface.As a label-free and high-throughput technique,SPRI enables simultaneously monitoring of the biomolecular interactions at low concentrations.We used SPRI as a label-free and parallel method to detect different proteins based on protein microarray.Bovine Serum Albumin(BSA),Casein and Immunoglobulin G(IgG)were immobilized onto the Au surface of a gold-coated glass chip as spots forming a 6×6 matrix.These proteins can be discriminated directly by changing the incident angle of light.Excellent reproducibility for label-free detection of protein molecules was achieved.This SPRI platform represents a simple and robust method for performing high-sensitivity detection of protein microarray.

Operando investigation of particle re-entrainment mechanism in electrostatic capture process on the lab-on-a-chip

Inhalable particle is a harmful air pollutant that causes a significant threat to people's health and ecological environments,which should be removed to purify air,but there exists limited removal efficiency due to particle re-entrainment.Here,Operando observation system based on microscopic visualization method is developed to make in situ test of particle migration,deposition and re-entrainment characteristics on a lab-on-a-chip to achieve the investigation in micro-level scale.The deposition evolution of charged particles is recorded in electric field region intuitively,which confirms the fracture of particle chain occurs during the growth process of deposited particles.It captures the instantaneous process that a larger particle with micron size due to the coagulation of submicron particles fractures from main body of the particle chain for the first time.The analysis of migration behavior of a single submicron particle near electrode surface demonstrates the direct influence of drag force on the fracture of particle chain.This work is the first-time visualization of dynamic process and mechanism elucidation of particle re-entrainment at the micron level,and the findings will provide the theory support for the particle re-entrainment mechanism and bring inspires of enhancing capture efficiency of inhalable particle.

Photo-enhanced uranium recovery from spent fuel reprocessing wastewater via S-scheme 2D/0D C_(3)N_(5)/Fe_(2)O_(3) heterojunctions

Re-extracting environmentally transportable hexavalent uranium from wastew-ater produced by spent fuel reprocessing using the photocatalytic technology is a crucial strategy to avoid uranium pollution and recover nuclear fuel strategic resources.Here,we have designed S-scheme 2D/0D C_(3)N_(5)/Fe_(2)O_(3)heterojunction photocatalysts based on the built-in electric field and the energy band bend-ing theory,and have further revealed the immobilization process of hexavalent uranium conversion into relatively insoluble tetravalent uranium in terms of thermodynamics and kinetics.According to the results,the hexavalent uranium removal and recovery ratios in wastewater are as high as 93.38%and 83.58%,respectively.Besides,C_(3)N_(5)/Fe_(2)O_(3)heterojunctions also exhibit satisfactory cat-alytic activity and selectivity even in the presence of excessive impurity cations(including Na^(+),K^(+),Ca^(^(2+)),Mg^(2+),Sr^(2+),and Eu^(3+))or various organics(such as xylene,tributylphosphate,pyridine,tannic acid,citric acid,and oxalic acid).It is believed that this work can provide a potential opportunity for S-scheme heterojunction photocatalysts to re-enrich uranium from spent fuel wastewater.

A 3D Investigation of Geological Structure and Its Relationship to Mineralization in the Nanling-Xuancheng Ore District,Middle-Lower Yangtze River Metallogenic Belt,China

The Nanling-Xuancheng ore region of Anhui Province is located in the Middle-Lower Yangtze River metallogenic belt.Insufficient exploration and research have been carried out in this newly defined ore district,although the Chating large porphyry Cu-Au deposit and a few middle-sized skarntype Cu polymetallic deposits have been discovered.In this study,we carried out high-resolution seismic reflection,magnetotelluric,gravity,and magnetic investigations,and constructed the 3 D geological structure of the uppermost crust in a depth range of 0-5 km using a comprehensive inversion of the new data constrained by previous deep-drilling data.We hence proposed some new insights to understand the mineralization processes of this district.A system of alternating ridges and valleys is suggested as the major structure pattern,composed of“two-layer structure”of the basins and“three-layer structure”of anticlines.Moreover,a conjugated fault system and its distribution features are revealed in our models,including the Jiangnan fault,Zhouwang fault,and Kunshan thrust nappe.The Jiangnan and Kunshan faults are suggested to have controlled the diagenesis and metallogenesis.Two deep concealed plutons located in Chating and Magushan are found,forming the Mesozoic diorite-felsic intrusions.These intrusions are believed to be the causes of hydrothermal deposits such as the Chating deposit and the Magushan deposit.

Yangshan A-Type Granites in the Lower Yangtze River Belt Formed by Ridge Subduction:Radiogenic Ca and Nd Isotopic Constraints

The Early Cretaceous aluminous A-type granites in the Lower Yangtze River belt(LYRB)can provide important insights into the Mesozoic magmatism in eastern China,but their origin remains highly controversial.In this study,radiogenic Ca-Nd isotopic analysis was performed for syenite porphyry and alkali-feldspar granite porphyry of the Yangshan pluton,a typical aluminous A-type granitic intrusion in the LYRB,to constrain its source and geodynamic setting.The results show thatε_(Ca)(126 Ma),ε_(Nd)(126 Ma)and K/Ca_(source) of the syenite porphyry range from-0.24 to+0.96,-7.2 to-6.0,and 0.31 to 1.26,respectively.The corresponding values for the alkali-feldspar granite porphyry range from 0.26 to 0.84,-8.0 to-6.1,and 0.79 to 1.08,respectively.Binary mixing modeling indicates that they were originated from the same sources with different proportion,namely,a mixing of 50%to 75%Neoproterozoic crust and 50%to 25%asthenospheric mantle.Together with previous works,we propose that the Early Cretaceous subduction of the ridge between the Pacific and Izanagi plates was responsible for the formation of the aluminous A-type granites in the LYRB.

A tale of elemental accumulation and recycling in the metamorphosed Keketale VMS-type Pb-Zn deposit,Altai Mountains

The elemental accumulation and recycling in the metamorphosed Keketale VMS-type Pb-Zn deposit of the Altai Mountains are presented in this study.Based on detailed fieldwork and microscopic observation,the formation of the deposit involved syngenetic massive sulfide mineralization and epigenetic superim-posed mineralization.Different generations of iron sulfides(i.e.,pyrite and pyrrhotite)with contrasting textural,elemental,and sulfur isotopic features were generated in primary mineralization(including hydrothermal iron sulfides,colloform pyrite)and secondary modification(including annealed iron sul-fides,oriented iron sulfides,and vein-pyrite).It is revealed that the spatial variation in textures and ele-ments of hydrothermal iron sulfides depends on the inhomogeneous fluid compositions and varied environment in VMS hydrothermal system.Both leached sulfur from the footwall volcanic rocks and reduced sulfur by the TSR process are regarded as important sulfur sources.Furthermore,large sulfur iso-topic fractionation and negativeδ^(34)S values were mainly caused by varied oxygen fugacity,and to a lesser extent,temperature fluctuation.The epigenetic polymetallic veins that contain sulfides and sulfosalts(e.g.,jordanite-geocronite,bournonite-seligmannite,boulangerite)were considered as the products of metamorphic fluid scavenged the metal-rich strata.All things considered,it is indicated that two epi-sodes of fluid with distinct origins were essential for the formation of the deposit.The predominant evolved seawater along with subordinate magmatic fluid mobilized metals from volcanic rocks and pre-cipitated massive sulfides near the seafloor are vital for primary mineralization.The metamorphic fluid remobilized metals(i.e.,FMEs:fluid mobile elements,e.g.,Pb,As,Sb)from neighboring volcanic and pyroclastic rocks and destabilized them within the fractured zone are responsible for secondary miner-alization,which enhances the economic value of the deposit.Accordingly,metal-rich Devonian strata had been successively swept by different origins of fluid,leading to progressively elemental enrichment and the formation of a large deposit.Furthermore,the current study enlightens that FME-bearing veins with economic benefits can be discovered near the metamorphosed VMS deposits.

Hydrothermal ore deposits in collisional orogens

Hydrothermal ore deposits at convergent plate boundaries represent extraordinary metal enrichment in the continental crust. They are generally associated with felsic magmatism in extensional settings at high thermal gradients. Although their formation is common during accretionary orogeny, more and more ore deposits have been discovered recently in the collisional orogens of China. Because collisional orogeny was operated in a compressional regime at low thermal gradients, it is not favorable for mobilization of ore-forming elements and thus for the production of hydrothermal ore deposits. Nevertheless, continental collision is generally preceded by oceanic subduction, which enables the preliminary enrichment of ore-forming elements in the mantle wedge due to chemical metasomatism by subducting slab-derived fluids. This gave rise to metal pre-enriched domains in the overriding lithosphere, which may be reactivated by extensional tectonism for hydrothermal mineralization either immediately during accretionary orogeny or at a later time during and after collisional orogeny. It is these tectonic processes that have resulted in the progressive enrichment of ore-forming elements through the geochemical differentiation of the subducting oceanic crust, the metasomatic mantle domains and the mafic juvenile crust, respectively, at different depths. Finally, the reactivation of metal pre-enriched domains by continental rifting in the orogenic lithosphere is the key to the metallogenesis of collisional orogens.

Review on the Tectonic Terranes Associated with Metallogenic Zones in Southeast Asia

The paper presents an overview of the relationships between the interior structures of tectonic terranes and the distribution of tectonic-metallogenic zones in Southeast Asia. Episodic tectonic activities occurred in this archipelagic area, generating metallogenic belts in multi-terranes. Since the Late Paleozoic, opening and closure of the Paleotethys and Neotethys led to multiple suture zones between different blocks, mainly between the Indochina terrane, the Nambung terrane, the Sibumasu terrane and the West Myanmar terrane. During the Mesozoic to Cenozoic, the formation of accreted terranes and their related islands was caused by subduction and collision processes between the Pacific and Australian plates toward the Eurasian Continent, forming Sundaland and its affiliated islands, the Philippines and its subsidiary islands, the Papua New Guinea terrane and its related islands and the Sunda epicontinental arc system. Within the margin of terranes resulted in the structural transfer zones, their secondary tectonic units can be divided into island arc belts, back-arc basins, suture zones, marginal fold belts and orogenic belts. The metallogenic assemblages are mainly distributed within these structural zones of the terranes. According to the relationship between these tectonic units and the distribution of mineral resources, the tectonic-metallogenic belts can be divided into 24 metallogenic belts in Southeast Asia. They are characterized by a diversity and frequency of metallogenic material combination which is likely to reflect the complexity of the material distribution during mineralization processes, mostly by the structural transformation during the dissociation-convergence process between multiple terranes. Therefore, the formation of ore deposits was not only restricted by the evolution(opening and closure) of Paleo-and Neotethys, but may also be controlled by the interaction of the terranes with different tectonic attributes which provided multiple sources of metallogenic material.

Piaoac Granites Related W-Sn Mineralization, Northern Vietnam: Evidences from Geochemistry, Zircon Geochronology and Hf Isotopes

Piaoac granites exposed in the Cao Bang region, northern Vietnam, are S-type granite, which are associated with W-Sn-Mo-Be-F mineralization. Zircon U-Pb ages, major and trace elements, mineral chemical and Hf isotopic compositions of the W-Sn-bearing granites from the Piaoac District have been investigated in detail. LA-ICP-MS U-Pb dating of zircon grains from these granites yielded ages of 82.5±2.3 and 82±1.8 Ma, representing an episode of Late Cretaceous magmatic event. These granites are characterized by high peraluminous and have typical S-type geochemical signatures with high SiO_2(72.37 wt.%–73.07 wt.%), high A/CNK values(1.61–1.65) and Al_2O_3(14.4 wt.%–15 wt.%). They are enriched in Rb, U, K, Th, Ta and Pb and display pronounced negative Ba, Sr, Nb, Ti and Eu(Eu/Eu*=0.19–0.24) anomalies. The high degree of fractional crystallization is characterized by low Rb, Sr, Ba and Eu concentrations with high ratios of La/Sm and Eu/Eu*. Zircon grains show εHf(t) values from-9.69 to-0.9 and the corresponding TDM2 range from 1.2 to 1.7 Ga, indicating that these granites could be derived from the Proterozoic basement rocks with minor input from mantle-derived magmas. The calculation of Fe^(3+) and Fe^(2+) of biotites indicates a low oxygen fugacity condition(log fO_2 ranging from 10-17 to 10-18 bars, below MH), which is favorable for the W-Sn mineralization. Tungsten and tin have been enriched in granitic magmas through fractionation, and low oxygen fugacity conditions have promoted the accumulation and transportation of W-Sn in the hydrothermal fluids, leading to deposition of mineral phases. The geochemical data suggest that Piaoac granites formed in an extensional setting related with the Late Cretaceous magmatism occurring large-scale lithospheric extensional in South China Block.

Regulation of the urea cycle by CPS1 O-GlcNAcylation in response to dietary restriction and aging

O-linked N-acetyl-glucosamine glycosylation(O-GlcNAcylation)of intracellular proteins is a dynamic process broadly implicated in age-related disease,yet it remains uncharacterized whether and how O-GlcNAcylation contributes to the natural aging process.O-GlcNAc transferase(OGT)and the opposing enzyme O-GlcNAcase(OGA)control this nutrient-sensing protein modification in cells.Here,we show that global O-GlcNAc levels are increased in multiple tissues of aged mice.In aged liver,carbamoyl phosphate synthetase 1(CPS1)is among the most heavilyO-GlcNAcylated proteins.CPS1O-GlcNAcylation is reversed by calorie restriction and is sensitive to genetic and pharmacological manipulations of theO-GlcNAc pathway.High glucose stimulates CPS1O-GlcNAcylation and inhibits CPS1 activity.Liver-specific deletion of OGT potentiates CPS1 activity and renders CPS1 irresponsive to further stimulation by a prolonged fasting.Our results identify CPS1 O-GlcNAcylation as a key nutrient-sensing regulatory step in the urea cycle during aging and dietary restriction,implying a role for mitochondrial O-GlcNAcylation in nutritional regulation of longevity.

Discovery of a Hadean xenocrystic zircon in the Cathaysia Block

The early history of Earth is poorly understood,due to the lack of ancient rocks formed after the formation of the newborn Earth,especiallyfor thefirst 500 million years(Hadean Eon).To our knowledge,this period is the most geodynamically vigorous in the crustal evolution history of Earth[1],and is characterized by intense collision with meteorites and the formation of a global magma ocean(~4.41 Ga;cf.review article by Ref.[2]).