Trend of Developing Aqueous Liquid and Gel Electrolytes for Sustainable,Safe,and High‑Performance Li‑Ion Batteries

Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and toxicity.The potential for environmental pollution and explosions resulting from battery damage or fracture is a critical concern.Water-based(aqueous)electrolytes have been receiving attention as an alternative to organic electrolytes.However,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous electrolytes.Therefore,developing novel aqueous electrolytes for sustainable,safe,high-performance LIBs remains challenging.This Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIBs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the electrolytes.These aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the electrolytes.In addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.

Postbiotics from Saccharomyces cerevisiae fermentation stabilize microbiota in rumen liquid digesta during grain-based subacute ruminal acidosis(SARA) in lactating dairy cows

Background Subacute ruminal acidosis(SARA)is a common metabolic disorder of high yielding dairy cows,and it is associated with dysbiosis of the rumen and gut microbiome and host inflammation.This study evaluated the impact of two postbiotics from Saccharomyces cerevisiae fermentation products(SCFP)on rumen liquid associated microbiota of lactating dairy cows subjected to repeated grain-based SARA challenges.A total of 32 rumen cannulated cows were randomly assigned to 4 treatments from 4 weeks before until 12 weeks after parturition.Treatment groups included a Control diet or diets supplemented with postbiotics(SCFPa,14 g/d Original XPC;SCFPb-1X,19 g/d Nutri Tek;SCFPb-2X,38 g/d Nutri Tek,Diamond V,Cedar Rapids,IA,USA).Grain-based SARA challenges were conducted during week 5(SARA1)and week 8(SARA2)after parturition by replacing 20%DM of the base total mixed ration(TMR)with pellets containing 50%ground barley and 50%ground wheat.Total DNA from rumen liquid samples was subjected to V3–V416S r RNA gene amplicon sequencing.Characteristics of rumen microbiota were compared among treatments and SARA stages.Results Both SARA challenges reduced the diversity and richness of rumen liquid microbiota,altered the overall composition(β-diversity),and its predicted functionality including carbohydrates and amino acids metabolic pathways.The SARA challenges also reduced the number of significant associations among different taxa,number of hub taxa and their composition in the microbial co-occurrence networks.Supplementation with SCFP postbiotics,in particular SCFPb-2X,enhanced the robustness of the rumen microbiota.The SCFP supplemented cows had less fluctuation in relative abundances of community members when exposed to SARA challenges.The SCFP supplementation promoted the populations of lactate utilizing and fibrolytic bacteria,including members of Ruminococcaceae and Lachnospiraceae,and also increased the numbers of hub taxa during non-SARA and SARA stages.Supplementation with SCFPb-2X prevented the fluctuations in the abundances of hub taxa that were positively correlated with the acetate concentration,andα-andβ-diversity metrics in rumen liquid digesta.Conclusions Induction of SARA challenges reduced microbiota richness and diversity and caused fluctuations in major bacterial phyla in rumen liquid microbiota in lactating dairy cows.Supplementation of SCFP postbiotics could attenuate adverse effects of SARA on rumen liquid microbiota.

Promoting role of Ru species on Ir-Fe/BN catalyst in 1,2-diols hydrogenolysis to secondary alcohols

Noble metal-based-bimetallic catalysts have been highly investigated and applied in wide applications including biomass transformation via regioselective C−O hydrogenolysis while further modification especially with noble metal is highly promising yet still under investigation.Herein,Ru was found as an effective modifier among the screened noble metals(Ru,Pt,Rh,Pd,Au,and Ag)for Ir-Fe/BN(Ir=5 wt%,Fe/Ir=0.25)catalyst in terminal C−O hydrogenolysis of 1,2-butanediol(1,2-BuD)to 2-butanol(2-BuOH).Only trace amount of Ru(up to 0.5 wt%)was effective in terms of high 2-BuOH selectivity(>60%)and activity(about twice).Larger amount of Ru species(3 wt%)highly enhanced the activity but gave low selectivity to 2-BuOH with by-products of terminal C−C bond scission.Optimized catalyst(Ru(0.5)-Ir-Fe/BN)was reusable at least 4 times and gave moderate 2-BuOH yield(47%)in hydrogenolysis of 1,2-BuD.The promoting effect of Ru addition(0.5 wt%)to Ir-Fe/BN on hydrogenolysis of various alcohols was also confirmed.Combining catalytic tests with various characterizations,the promotion mechanism of Ru species in trimetallic catalysts was clarified.The Ru species in Ru(0.5)-Ir-Fe/BN form alloy with Ir and are enriched at the interface with BN surface,and direct interaction between Ru and Fe was not necessary in Ru-Ir-Fe alloy.The interface of Ir and Fe on the surface of Ir-Fe alloy may work as active sites for 1,2-diols to secondary alcohols via direct C−O hydrogenolysis,in which Ru-modified Ir activates H_(2) to form hydride-like species.The activity of Ru species in C−C bond cleavage was highly suppressed due to the direct interaction with Ir species and less exposed to substrate.Larger loading amount of Ru species(3 wt%)led to the formation Ru-rich trimetallic alloy,which further works as active sites for C−C bond scission.

Bacteria colonization and gene expression related to immune function in colon mucosa is associated with growth in neonatal calves regardless of live yeast supplementation

Background As Holstein calves are susceptible to gastrointestinal disorders during the first week of life,understanding how intestinal immune function develops in neonatal calves is important to promote better intestinal health.Feeding probiotics in early life may contribute to host intestinal health by facilitating beneficial bacteria colonization and developing intestinal immune function.The objective of this study was to characterize the impact of early life yeast supplementation and growth on colon mucosa-attached bacteria and host immune function.Results Twenty Holstein bull calves received no supplementation(CON)or Saccharomyces cerevisiae boulardii(SCB)from birth to 5 d of life.Colon tissue biopsies were taken within 2 h of life(D0)before the first colostrum feeding and 3 h after the morning feeding at d 5 of age(D5)to analyze mucosa-attached bacteria and colon transcriptome.Metagenome sequencing showed that there was no difference inαandβdiversity of mucosa-attached bacteria between day and treatment,but bacteria related to diarrhea were more abundant in the colon mucosa on D0 compared to D5.In addition,q PCR indicated that the absolute abundance of Escherichia coli(E.coli)decreased in the colon mucosa on D5 compared to D0;however,that of Bifidobacterium,Lactobacillus,and Faecalibacterium prausnitzii,which could competitively exclude E.coli,increased in the colon mucosa on D5 compared to D0.RNA-sequencing showed that there were no differentially expressed genes between CON and SCB,but suggested that pathways related to viral infection such as“Interferon Signaling”were activated in the colon mucosa of D5 compared to D0.Conclusions Growth affected mucosa-attached bacteria and host immune function in the colon mucosa during the first 5 d of life in dairy calves independently of SCB supplementation.During early life,opportunistic pathogens may decrease due to intestinal environmental changes by beneficial bacteria and/or host immune function.Predicted activation of immune function-related pathways may be the result of host immune function development or suggest other antigens in the intestine during early life.Further studies focusing on the other antigens and host immune function in the colon mucosa are required to better understand intestinal immune function development.

Effects of improved amino acid balance diet on lysine mammary utilization, whole body protein turnover and muscle protein breakdown on lactating sows

Background The study objective was to test the hypothesis that low crude protein(CP)diet with crystalline amino acids(CAA)supplementation improves Lys utilization efficiency for milk production and reduces protein turnover and muscle protein breakdown.Eighteen lactating multiparous Yorkshire sows were allotted to 1 of 2 isocaloric diets(10.80 MJ/kg net energy):control(CON;19.24%CP)and reduced CP with“optimal”AA profile(OPT;14.00%CP).Sow body weight and backfat were recorded on d 1 and 21 of lactation and piglets were weighed on d 1,14,18,and 21 of lactation.Between d 14 and 18,a subset of 9 sows(CON=4,OPT=5)was infused with a mixed solution of 3-[methyl-2H3]histidine(bolus injection)and[13C]bicarbonate(priming dose)first,then a constant 2-h[13C]bicarbonate infusion followed by a 6-h primed constant[1-13C]lysine infusion.Serial blood and milk sampling were performed to determine plasma and milk Lys enrichment,Lys oxidation rate,whole body protein turnover,and muscle protein breakdown.Results Over the 21-d lactation period,compared to CON,sows fed OPT had greater litter growth rate(P<0.05).Compared to CON,sows fed OPT had greater efficiency of Lys(P<0.05),Lys mammary flux(P<0.01)and whole-body protein turnover efficiency(P<0.05).Compared to CON,sows fed OPT tended to have lower whole body protein breakdown rate(P=0.069).Muscle protein breakdown rate did not differ between OPT and CON(P=0.197).Conclusion Feeding an improved AA balance diet increased efficiency of Lys and reduced whole-body protein turnover and protein breakdown.These results imply that the lower maternal N retention observed in lactating sows fed improved AA balance diets in previous studies may be a result of greater partitioning of AA towards milk rather than greater body protein breakdown.

Gas microchannel plate-pixel detector for X-ray polarimetry

POLAR-2 is a gamma-ray burst(GRB)polarimeter that is designed to study the polarization in GRB radiation emissions,aiming to improve our knowledge of related mechanisms.POLAR-2 is expected to utilize an on-board polarimeter that is sensitive to soft X-rays(2-10 keV),called low-energy polarization detector.We have developed a new soft X-ray polari-zation detector prototype based on gas microchannel plates(GMCPs)and pixel chips(Topmetal).The GMCPs have bulk resistance,which prevents charging-up effects and ensures gain stability during operation.The detector is composed of low outgassing materials and is gas-sealed using a laser welding technique,ensuring long-term stability.A modulation factor of 41.28%±0.64% is obtained for a 4.5 keV polarized X-ray beam.A residual modulation of 1.96%±0.58% at 5.9 keV is observed for the entire sensitive area.

Highly Aligned Ternary Nanofiber Matrices Loaded with MXene Expedite Regeneration of Volumetric Muscle Loss

Current therapeutic approaches for volumetric muscle loss(VML)face challenges due to limited graft availability and insufficient bioactivities.To overcome these limitations,tissue-engineered scaffolds have emerged as a promising alternative.In this study,we developed aligned ternary nanofibrous matrices comprised of poly(lactide-co-ε-caprolactone)integrated with collagen and Ti_(3)C_(2)T_(x)MXene nanoparticles(NPs)(PCM matrices),and explored their myogenic potential for skeletal muscle tissue regeneration.The PCM matrices demonstrated favorable physicochemical properties,including structural uniformity,alignment,microporosity,and hydrophilicity.In vitro assays revealed that the PCM matrices promoted cellular behaviors and myogenic differentiation of C2C12 myoblasts.Moreover,in vivo experiments demonstrated enhanced muscle remodeling and recovery in mice treated with PCM matrices following VML injury.Mechanistic insights from next-generation sequencing revealed that MXene NPs facilitated protein and ion availability within PCM matrices,leading to elevated intracellular Ca^(2+)levels in myoblasts through the activation of inducible nitric oxide synthase(i NOS)and serum/glucocorticoid regulated kinase 1(SGK1),ultimately promoting myogenic differentiation via the m TOR-AKT pathway.Additionally,upregulated i NOS and increased NO–contributed to myoblast proliferation and fiber fusion,thereby facilitating overall myoblast maturation.These findings underscore the potential of MXene NPs loaded within highly aligned matrices as therapeutic agents to promote skeletal muscle tissue recovery.

Non-invasive estimation of the powder size distribution from a single speckle image

Non-invasive characterization of powders may take one of two approaches:imaging and counting individual particles;or relying on scattered light to estimate the particle size distribution(PSD)of the ensemble.The former approach runs into practical difficulties,as the system must conform to the working distance and other restrictions of the imaging optics.The latter approach requires an inverse map from the speckle autocorrelation to the particle sizes.The principle relies on the pupil function determining the basic sidelobe shape,whereas the particle size spread modulates the sidelobe intensity.We recently showed that it is feasible to invert the speckle autocorrelation and obtain the PSD using a neural network,trained efficiently through a physics-informed semi-generative approach.In this work,we eliminate one of the most time-consuming steps of our previous method by engineering the pupil function.By judiciously blocking portions of the pupil,we sacrifice some photons but in return we achieve much enhanced sidelobes and,hence,higher sensitivity to the change of the size distribution.The result is a 60×reduction in total acquisition and processing time,or 0.25 seconds per frame in our implementation.Almost real-time operation in our system is not only more appealing toward rapid industrial adoption,it also paves the way for quantitative characterization of complex spatial or temporal dynamics in drying,blending,and other chemical and pharmaceutical manufacturing processes.

Regulation of the growth of sprouting roots of black locust seedlings using root barrier panels

How can we regulate an invasive alien species of high commercial value?Black locust(Robinia pseudoacacia L.)has a unique capacity for seed dispersal and high germination.Field surveys indicate that black locust increases its growing area with sprouting roots and the elongation of horizontal roots at a soil depth of 10 cm.Therefore,a method to regulate the development of horizontal roots could be eff ective in slowing the invasiveness of black locust.In this study,root barrier panels were tested to inhibit the growth of horizontal roots.Since it is labor intensive to observe the growth of roots in the fi eld,it was investigated in a nursery setting.The decrease in secondary fl ush,an increase in yellowed leafl ets,and the height in the seedlings were measured.Installing root barrier panels to a depth of 30 cm eff ectively inhibit the growth of horizontal roots of young black locust.

The sperm-interacting proteome in the bovine isthmus and ampulla during the periovulatory period

Background Spermatozoa interact with oviduct secretions before fertilization in vivo but the molecular players of this dialog and underlying dynamics remain largely unknown.Our objectives were to identify an exhaustive list of sperm-interacting proteins(SIPs)in the bovine oviduct fluid and to evaluate the impact of the oviduct anatomical region(isthmus vs.ampulla)and time relative to ovulation(pre-ovulatory vs.post-ovulatory)on SIPs number and abundance.Methods Pools of oviduct fluid(OF)from the pre-ovulatory ampulla,pre-ovulatory isthmus,post-ovulatory ampulla,and post-ovulatory isthmus in the side of ovulation were collected from the slaughterhouse.Frozen-thawed bull sperm were incubated with OF or phosphate-buffered saline(control)for 60 min at 38.5℃.After protein extraction and digestion,sperm and OF samples were analyzed by nanoLC-MS/MS and label-free protein quantification.Results A quantitative comparison between proteins identified in sperm and OF samples(2333 and 2471 proteins,respectively)allowed for the identification of 245 SIPs.The highest number(187)were found in the pre-ovulatory isthmus,i.e.,time and place of the sperm reservoir.In total,41 SIPs(17%)were differentially abundant between stages in a given region or between regions at a given stage and 76 SIPs(31%)were identified in only one region×stage condition.Functional analysis of SIPs predicted roles in cell response to stress,regulation of cell motility,fertilization,and early embryo development.Conclusion This study provides a comprehensive list of SIPs in the bovine oviduct and evidences dynamic spatiotemporal changes in sperm-oviduct interactions around ovulation time.Moreover,these data provide protein candidates to improve sperm conservation and in vitro fertilization media.

Winery by‑products as a feed source with functional properties:dose–response effect of grape pomace,grape seed meal,and grape seed extract on rumen microbial community and their fermentation activity in RUSITEC

Background Grape and winery by-products have nutritional values for cattle and also contain functional compounds like phenols,which not only bind to protein but can also directly affect microbiota and their function in the rumen.We characterized the nutritional and functional effects of grape seed meal and grape pomace as well as an effective dosage of grape phenols on ruminal microbiota and fermentation characteristics using a rumen simulation technique.Results Six diets(each n=8)were compared including a control diet(CON,no by-product),a positive control diet(EXT,CON+3.7%grape seed extract on a dry matter(DM)basis),two diets with grape seed meal at 5%(GS-low)and 10%(GS-high),and two diets with grape pomace:at 10%(GP-low)and 20%(GP-high),on a DM basis.The inclusion of the by-product supplied total phenols at 3.4%,0.7%,1.4%,1.3%,and 2.7%of diet DM for EXT,GS-low,GS-high,GP-low,and GP-high,respectively.Diets were tested in four experimental runs.All treatments decreased ammonia concentrations and the disappearances of DM and OM(P<0.05)compared to CON.EXT and GP-high lowered butyrate and odd-and branch-chain short-chain fatty acids while increased acetate compared to CON(P<0.05).Treatments did not affect methane formation.EXT decreased the abundance of many bacterial genera including those belonging to the core microbiota.GP-high and EXT consistently decreased Olsenella and Anaerotipes while increased Ruminobacter abundances.Conclusion The data suggest that the inclusion of winery by-products or grape seed extract could be an option for reducing excessive ammonia production.Exposure to grape phenols at a high dosage in an extract form can alter the rumen microbial community.This,however,does not necessarily alter the effect of grape phenols on the microbial community function compared to feeding high levels of winery by-products.This suggests the dominant role of dosage over the form or source of the grape phenols in affecting ruminal microbial activity.In conclusion,supplementing grape phenols at about 3%of diet DM is an effective dosage tolerable to ruminal microbiota.

湘西北慈利大庸地区上震旦统—下寒武统沉积特征及层序地层划分

通过对各类层序界面的识别,以沉积特征、副层序和体系域与结构转换面等层序分析,进行露头层序地层学研究,将湘西北慈利 大庸地区台缘斜坡相区上震旦统—下寒武统划分为11个Ⅲ级层序,其中上震旦统7个、下寒武统4个,主要是Ⅱ型层序。在区域层序地层对比、分析的基础上初步讨论了露头层序地层分析中存在的问题。

CIPK9: a calcium sensor-interacting protein kinase required for low-potassium tolerance in Arabidopsis

Potassium is one of the major macro-nutrients essential for a number of cellular processes in plants. Low potassium level in the soil represents a limiting factor for crop production. Recent studies have identified potassium transporters that are involved in potassium acquisition, and some of them are critical for potassium nutrition under low potassium conditions. However, little is understood on the molecular components involved in low potassium signaling and responses. We report here the identification ofa calcineurin B-like protein-interacting protein kinase （CIPK9） as a critical regulator of low potassium response in ,Arabidopsis. The CIPK9 gene was responsive to abiotic stress conditions, and its transcript was inducible in both roots and shoots by potassium deprivation. Disruption of CIPK9 function rendered the mutant plants hypersensitive to low potassium media. Further analysis indicated that K^＋ uptake and content were not affected in the mutant plants, implying CIPK9 in the regulation of potassium utilization or sensing processes.

REE Tetrad Effects in Rare-metal Granites

Described in this paper are the characteristics of tetrad effects of REE in rare-metal granites.Based on the analytical data and experimental geochemical data available,it is pointed out that the tetrad effects of REE in the granites are produced in the metal-fluid system.Intense fractional crystallization of granitic melt(containing REE accessary minerals)and its interaction with volatile-rich(F,Cl)fluid are the major factors leading to the tetrad effects of REE.From this,this paper presents a composite genetic model for high-degree fractional crystallization-volatile-rich fluid metasomatism of rare-metal granites.With the model,quantitative calculations have been made.Meanwhile,it is pointed out that the tetrad effects of REE can be used as an important indicator to distinguish mineralized granites from barren ones.

Relationship between Traditional Chinese Medicine Syndrome Type and Coronary Arteriography of Acute Coronary Syndrome

Objective: To explore the relationship of Traditional Chinese Medicine (TCM) Syndrome type and coronary arteriography (CAG) with respect to the number and degree of stenosed branches of coronary artery (CA) and ACC/AHA stage of acute coronary syndrome (ACS), to provide an objective evidence for TCM Syndrome typing on ACS Methods: Ninety patients of ACS with their TCM Syndrome typing and CAG successfully conducted were enrolled in this study. They were classified into 3 Syndrome types, the blood stasis type (type I ), the phlegm stagnant with blood stasis type (type II ),and the endogenous collateral Wind type (type III) The scores of the number and severity of the stenosis branch of CA and ACC/AHA lesion stage in different Syndrome types were calculated respectively and analysed statistically by Ridit analysis. Results: The number of stenosed branches increased gradually with the Syndrome type changing from I -II-III, compared the type III with the other two types(P<0. 01). The severity of stenosis in type I and II were similar, but that of Type III, much aggravated was significantly different from that in the former two (P<0. 01) . The ACC/AHA stage of coronary lesion tended to be more complex as the Syndrome type changed, patients of TCM type I and II had mostly lesion of stage A or Bl , while lesion in majority of patients of type III belonged to stage B2 or C, comparison between the three types showed significant difference (P<0.01). Conclusion: Most ACS patients of TCM Syndrome type III with tri-branch, severe stenosed coronary arteries, belong to the complex ACC/AHA stage of B2 and C.

Structure and evolution of the continental margin off Norway and the Barents Sea

The Norwegian Margin formed in response to early Cenozoic continental breakup and subsequent opening of the Norwegian-Greenland Sea. There is a welldefined margin segmentation and the various segments are characterized by distinct crustal properties, structural and magmatic styles, and post-opening history of vertical motions. The sedimentary basins at the conjugate continental margins off Norway and Greenland and in the western Barents Sea developed as a result of a series of post-Caledonian rift episodes until early Cenozoic time, when complete continental separation took place.

Interannual and Decadal Variability of Landfalling Tropical Cyclones in the Southeast Coastal States of the United States

The interannual variability of the Atlantic tropical cyclone (TC) frequency is well known. Separately, recent studies have also suggested that a much longer, multidecadal (40-60 year) trend might be emerging from the recent increase in Atlantic TC activity. However, the overall structure of the intrinsic frequencies (or temporal modes) of Atlantic TC activity is not yet known. The focus of this study is to systematically an-alyze the intrinsic frequencies of Atlantic TC activity using hurricane and tropical storm landfall data collec-ted along the southeast coast(SEC) of the United States, Based on an Empirical Mode Decomposition (EMD) analysis of the frequency of landfall TCs along the SEC from 1887-1999, we have found that Atlantic TC activity has four primary, temporal modes. The interannual and multidecadal modes reported in the published literature are two such modes. After identifying all primary modes, the relative importance of each mode and its physical cause can be analyzed. For example, the most energetic mode is the interannual mode (2-7 year period). This mode is known to be associated with the 2-7 year El Nino/ La Ni na cycle. The average number of annual landfalling TCs along (he SEC decreased by 24% during El Nino years, but did not show significant increase during weak and moderate La Nina years. However, intense La Nina years were generally associated with more than average landfalling TCs along the SEC. The effects of El Nino and La Nina also became more significant when only hurricanes were considered. The significance of the effects of El Nino and La Nina on landfalling TCs and hurricanes in different US southeast coastal states showed significant differences.

Induction of ischemic tolerance as a promising treatment against diabetic retinopathy

Diabetic retinopathy is a leading cause of acquired blindness, and it is the most common ischemic disorder of the retina. Available treatments are not very effective. Efforts to inhibit diabetic reti- nopathy have focused either on highly specific therapeutic approaches for pharmacologic targets or using genetic approaches to change expression of certain enzymes. However, it might be wise to choose innovative treatment modalities that act by multiple potential mechanisms. The resis- tance to ischemic injury, or ischemic tolerance, can be transiently induced by prior exposure to a non-injurious preconditioning stimulus. A complete functional and histologic protection against retinal ischemic damage can be achieved by previous preconditioning with non-damaging isch- emia. In this review, we will discuss evidence that supports that ischemic conditioning could help avert the dreaded consequences that results from retinal diabetic damage.

Dissolved organic matter tracers reveal contrasting characteristics across high arsenic aquifers in Cambodia:A fluorescence spectroscopy study

Organic matter in the environment is involved in many biogeochemical processes,including the mobilization of geogenic trace elements,such as arsenic,into groundwater.In this paper we present the use of fluorescence spectroscopy to characterize the dissolved organic matter (DOM) pool in heavily arsenicaffected groundwaters in Kandal Province,Cambodia.The fluorescence DOM (fDOM) characteristics between contrasting field areas of differing dominant lithologies were compared and linked to other hydrogeochemical parameters,including arsenic and dissolved methane as well as selected sedimentary characteristics.Absorbance-corrected fluorescence indices were used to characterize depth profiles and compare field areas.Groundwater fDOM was generally dominated by terrestrial humic and fulvic-like components,with relatively small contributions from microbially-derived,tryptophan-like components.Groundwater fDOM from sand-dominated sequences typically contained lower tryptophan-like,lower fulvic-like and lower humic-like components,was less bioavailable,and had higher humification index than clay-dominated sequences.Methane concentrations were strongly correlated with fDOM bioavailability as well as with tryptophan-like components,suggesting that groundwater methane in these arsenic-prone aquifers is likely of biogenic origin.A comparison of fDOM tracers with sedimentary OM tracers is consistent with the hypothesis that external,surface-derived contributions to the aqueous DOM pool are an important control on groundwater hydrogeochemistry.

Re–Os dating of molybdenite and in-situ Pb isotopes of sulfides from the Lamo Zn–Cu deposit in the Dachang tin-polymetallic ore field, Guangxi, China

The Dachang tin-polymetallic district, Guangxi,China, is one of the largest tin ore fields in the world. Both cassiterite-sulfide and Zn–Cu skarn mineralization are hosted in the Mid-Upper Devonian carbonate-rich sediments adjacent to the underlying Cretaceous Longxianggai granite(91–97 Ma). The Lamo Zn–Cu deposit is a typical skarn deposit in the district and occurs at the contact zone between the Upper Devonian limestone and the granite.The ore minerals mainly consist of sphalerite, arsenopyrite,pyrrhotite, galena, chalcopyrite, and minor molybdenite.However, the age of mineralization and source of the metals are not well constrained. In this study, we use the molybdenite Re–Os dating method and in-situ Pb isotopes of sulfides from the Lamo deposit for the first time in order to directly determine the age of mineralization and the tracing source of metals. Six molybdenite samples yielded a more accurate Re–Os isochron age of 90.0 ± 1.1 Ma(MSWD = 0.72), which is much younger than the reported garnet Sm–Nd isochron age of 95 ± 11 Ma and quartz fluid inclusions Rb–Sr isochron age of 99 ± 6 Ma. This age is also interpreted as the age of Zn–Cu skarn mineralization in the Dachang district. Further, in this study we found that in-situ Pb isotopes of sulfides from the Lamo deposit and feldspars in the district's biotite granite and granitic porphyry dikes have a narrow range and an overlap of Pb isotopic compositions(^(206) Pb/^(204) Pb =18.417–18.594,^(207) Pb/^(204) Pb = 15.641–15.746, and^(208) Pb/^(204) Pb = 38.791–39.073), suggesting that the metals were mainly sourced from Cretaceous granitic magma.