The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,w...The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,west of the Baimashan granitic batholith.In order to discern the characteristics of the ore-formingfluids,the underlying mineralization processes,and establish a foundation for the origin of the Yueguang gold depositfluid inclusion micro-thermometry,as well as quartz hydrogen and oxygen isotope analysis,have been carried out on samples obtained from various stages of mineralization.The hydrothermal miner-alization stages within the Yueguang gold deposit can be categorized into three stages:(i)the barren,pre-ore quartz-pyrite stage(Stage Ⅰ),the quartz-pyrite-gold stage(Stage Ⅱ),and the post-ore quartz-carbonate stage(Stage Ⅲ),with the second stage being the main mineralization stage.Thefluid inclusions identified in samples from the main min-eralization stage can predominantly be described with the NaCl–H_(2)O and CO_(2)–NaCl–H_(2)O systems.These inclusions display homogenization temperatures ranging from 158.8 to 334.9℃,and thefluid salinity ranges from 0.3%to 4.0%(wt.%NaCl equiv.).Laser Raman spectroscopy analysis of individual inclusions further reveals the presence of gas-phases such as CO_(2),CH_(4),and N_(2).Isotopic analysis indicatesδ^(18)Ofluid values ranging from 3.95 to 6.7‰ and δDH_(2)O values ranging from-71.9 to-55.7‰.These results indi-cate that the ore-formingfluid of the Yueguang gold deposit belongs to metamorphic hydrothermalfluids of middle-low temperature and low salinity.In the process of ore formation,gold is transported in the form of Au(HS)2-complexes,with gold deposition being driven byfluid immiscibility.Therefore,the Yueguang gold deposit is categorized as an orogenic gold deposit dominated by metamorphic hydrother-malfluid.It may become a new target for gold exploration in the Baimashan region,central Hunan Province.展开更多
BACKGROUND Gallstones are common lesions that often require surgical intervention.Laparo-scopic cholecystectomy is the treatment of choice for symptomatic gallstones.Preoperatively,the anatomical morphology of the cys...BACKGROUND Gallstones are common lesions that often require surgical intervention.Laparo-scopic cholecystectomy is the treatment of choice for symptomatic gallstones.Preoperatively,the anatomical morphology of the cystic duct(CD),needs to be accurately recognized,especially when anatomical variations occur in the CD,which is otherwise prone to bile duct injury.However,at present,there is no optimal classification system for CD morphology applicable in clinical practice,and the relationship between anatomical variations in CDs and gallstones remains to be explored.AIM To create a more comprehensive clinically applicable classification of the morphology of CD and to explore the correlations between anatomic variants of CD and gallstones.METHODS A total of 300 patients were retrospectively enrolled from October 2021 to January 2022.The patients were divided into two groups:The gallstone group and the nongallstone group.Relevant clinical data and anatomical data of the CD based on magnetic resonance cholangiopancreatography(MRCP)were collected and analyzed to propose a morphological classification system of the CD and to explore its relationship with gallstones.Multivariate analysis was performed using logistic regression analyses to identify the independent risk factors using variables that were significant in the univariate analysis.RESULTS Of the 300 patients enrolled in this study,200(66.7%)had gallstones.The mean age was 48.10±13.30 years,142(47.3%)were male,and 158(52.7%)were female.A total of 55.7%of the patients had a body mass index(BMI)≥24 kg/m2.Based on the MRCP,the CD anatomical typology is divided into four types:Type I:Linear,type II:n-shaped,type III:S-shaped,and type IV:W-shaped.Univariate analysis revealed differences between the gallstone and nongallstone groups in relation to sex,BMI,cholesterol,triglycerides,morphology of CD,site of CD insertion into the extrahepatic bile duct,length of CD,and angle between the common hepatic duct and CD.According to the multivariate analysis,female,BMI(≥24 kg/m2),and CD morphology[n-shaped:Odds ratio(OR)=10.97,95%confidence interval(95%CI):5.22-23.07,P<0.001;S-shaped:OR=4.43,95%CI:1.64-11.95,P=0.003;W-shaped:OR=7.74,95%CI:1.88-31.78,P=0.005]were significantly associated with gallstones.CONCLUSION The present study details the morphological variation in the CD and confirms that CD tortuosity is an independent risk factor for gallstones.展开更多
The Upper Carboniferous Benxi Formation of the Ordos Basin is the lowest strata overlying Middle Ordovician above the major ca.150-Myr sedimentary gap that characterizes the entire North China Block(NCB).We apply an i...The Upper Carboniferous Benxi Formation of the Ordos Basin is the lowest strata overlying Middle Ordovician above the major ca.150-Myr sedimentary gap that characterizes the entire North China Block(NCB).We apply an integrated analysis of stratigraphy,petrography,and U-Pb dates and Hf isotopes on detrital zircons to investigate its provenance and relationships to the progressive collisions that formed the Xing’an-Mongolia Orogenic Belt to the north and the Qinling Orogenic Belt to the south.The results show that,in addition to regional patterns of siliciclastic influx from these new uplifted sources,the Benxi Formation is composed of two sequences corresponding to long-term glacial-interglacial cycles during the Moscovian to lower Gzhelian stages which drove global changes of eustatic sea level and weathering.The spatio-temporal distribution of sediment isopachs and facies indicate there were two sediment-infilling pulses,during which the southern and the northern Ordos Basin developed tidal-reworked deltas.The age spectra from detrital zircons,trace element patterns and εNd(t)values reveal that the siliciclastics forming the southern delta was sourced in the Qinling Orogenic Belt,whereas the northern delta was derived from the Xing’an-Mongolia Orogenic Belt.The source-to-sink evolution of this Upper Paleozoic system records the progressive development of orogenic belts and uplifts forming on the southern and northern margins of the NCB prior to its collisions with the South China and the Siberian plates,respectively.展开更多
Fluorite is one of the important mineral raw materials in the industry.In China,it is mainly distributed in the provinces and regions such as Hunan,Zhejiang,Jiangxi,Inner Mongolia,Fujian,and Henan provinces,boasting h...Fluorite is one of the important mineral raw materials in the industry.In China,it is mainly distributed in the provinces and regions such as Hunan,Zhejiang,Jiangxi,Inner Mongolia,Fujian,and Henan provinces,boasting huge reserves and large numbers of deposits.However,most of the fluorite deposits are on a small or medium scale.The main fluorite deposits in China were studied in this paper.Their geological features and metallogenic regularity were summarized and compared.Meanwhile,based on their main genetic factors including metallogenic fluid sources and main metallogenic geological processes,they were divided into two groups,namely meso-epithermal deposits and magmatic-hydrothermal deposits.Furthermore,based on the prospecting achievements and research progress obtained in fluorite deposits in recent years,prospecting potential predictions were made for the metallogenic prospect areas and major prospecting areas of fluorite in China.This aims to provide a theoretical basis and direction for future fluorite prospecting in China.展开更多
Numerous intrusive bodies of mafic–ultramafic to felsic compositions are exposed in association with volcanic rocks in the Late Permian Emeishan large igneous province(ELIP),southwestern China.Most of the granitic ro...Numerous intrusive bodies of mafic–ultramafic to felsic compositions are exposed in association with volcanic rocks in the Late Permian Emeishan large igneous province(ELIP),southwestern China.Most of the granitic rocks in the ELIP were derived by differentiation of basaltic magmas with a mantle connection,and crustal magmas have rarely been studied.Here we investigate a suite of mafic dykes and Ⅰ-type granites that yield zircon U-Pb emplacement ages of 259.9±1.2 Ma and 259.3±1.3 Ma,respectively.The εHf(t)values of zircon from the DZ mafic dyke are–0.3 to 9.4,and their corresponding TDM1 values are in the range of 919–523 Ma.The εHf(t)values of zircon from the DSC Ⅰ-type granite are between–1 and 3,with TDM1 values showing a range of 938–782 Ma.We also present zircon O isotope data on crust-derived felsic intrusions from the ELIP for the first time.The δ18O values of zircon from the DSC Ⅰ-type granite ranges from 4.87‰to 7.5‰.The field,petrologic,geochemical and isotopic data from our study lead to the following salient findings.(i)The geochronological study of mafic and felsic intrusive rocks in the ELIP shows that the ages of mafic and felsic magmatism are similar.(ii)The DZ mafic dyke and high-Ti basalts have the same source,i.e.,the Emeishan mantle plume.The mafic dyke formed from magmas sourced at the transitional depth between from garnet-lherzolite and spinel-lherzolite,with low degree partial melting(<10%).(iii)The Hf-O isotope data suggest that the DSC Ⅰ-type granite was formed by partial melting of Neoproterozoic juvenile crust and was contaminated by minor volumes of chemically weathered ancient crustal material.(iv)The heat source leading to the formation of the crust-derived felsic rocks in of the ELIP is considered to be mafic–ultramafic magmas generated by a mantle plume,which partially melted the overlying crust,generating the felsic magma.展开更多
The Early Cretaceous granitoids that are widespread in the Tengchong terrane of Southwest China play a critical role in understanding the tectonic framework associated with the Tethyan oceans. In this study, we presen...The Early Cretaceous granitoids that are widespread in the Tengchong terrane of Southwest China play a critical role in understanding the tectonic framework associated with the Tethyan oceans. In this study, we present a detailed description of zircon U-Pb ages, whole-rock geochemistry and Hf isotopes for the Laoxiangkeng pluton in the eastern Tengchong terrane and elucidate their petrogenesis and geodynamic implications. Zircon U-Pb dating of the Laoxiangkeng pluton yields ages of 114 ± 1 Ma and 115 ± 1 Ma,which imply an Early Cretaceous magmatic event. The Laoxiangkeng pluton enriched in Si and Na, is calcalkaline and metaluminous, and has the characteristics of highly fractionated I-type granites. Zircons from the pluton have calculated ε_(Hf)(t) values of-12.7 to-3.7 and two-stage model ages of 1327-1974 Ma,respectively, indicating a mixed source of partial melting of Paleo-Neoproterozoic crust-derived compositions with some inputs of mantle-derived magmas. By integrating all available data for the regional tectonic evolution of the eastern Tethys tectonic domain, we conclude that the Early Cretaceous magmatism in the Tengchong terrane was produced by the northeastward subduction of the Meso-Tethyan Bangong-Nujiang Ocean.展开更多
Density functional theory (DFT) calculations are reported for the structures of neutral and zwitterionic glycine-(CHaOH)n where n=1-6. Initial geometries of the clusters of neutral and zwitterionic glycine with 1-...Density functional theory (DFT) calculations are reported for the structures of neutral and zwitterionic glycine-(CHaOH)n where n=1-6. Initial geometries of the clusters of neutral and zwitterionic glycine with 1-6 methanol molecules are fully optimized at B3LYP/6-31+G^* level of theory. The lowest energy configurations are located and their hydrogen bond structures are analyzed. Theoretical prediction reveals that the methanols prefer to locate near the carboxylic acid group for the small clusters (n_〈3) with the neutral form while the configurations with the methanols bridging the acid and the amino group are favorite in the zwitterionic form clusters. When the number of the methanol molecules in the clusters reaches five and six, the two forms tend to be isoenergetic.展开更多
A GaN-based high electron mobility transistor(HEMT)with p-GaN islands buried layer(PIBL)for terahertz applications is proposed.The introduction of a p-GaN island redistributes the electric field in the gate–drain cha...A GaN-based high electron mobility transistor(HEMT)with p-GaN islands buried layer(PIBL)for terahertz applications is proposed.The introduction of a p-GaN island redistributes the electric field in the gate–drain channel region,thereby promoting the formation of electronic domains in the two-dimensional electron gas(2DEG)channel.The formation and regulation mechanism of the electronic domains in the device are investigated using Silvaco-TCAD software.Simulation results show that the 0.2µm gate HEMT with a PIBL structure having a p-GaN island doping concentration(Np)of 2.5×10^(18)cm^(−3)–3×10^(18)cm^(−3)can generate stable oscillations up to 344 GHz–400 GHz under the gate–source voltage(V_(gs))of 0.6 V.As the distance(D_(p))between the p-GaN island and the heterojunction interface increases from 5 nm to 15 nm,the fundamental frequency decreases from 377 GHz to 344 GHz,as well as the ratio of oscillation current amplitude of the fundamental component to the average component I_(f1)/I_(avg) ranging from 2.4%to 3.84%.展开更多
The effects of various notch structures on direct current(DC) and radio frequency(RF) performances of AlGaN/GaN high electron mobility transistors(HEMTs) are analyzed.The AlGaN/GaN HEMTs,each with a 0.8-μm gate lengt...The effects of various notch structures on direct current(DC) and radio frequency(RF) performances of AlGaN/GaN high electron mobility transistors(HEMTs) are analyzed.The AlGaN/GaN HEMTs,each with a 0.8-μm gate length,50-μm gate width,and 3-μm source-drain distance in various notch structures at the AlGaN/GaN barrier layer,are manufactured to achieve the desired DC and RF characteristics.The maximum drain current(I_(ds,max)),pinch-off voltage(V_(th)),maximum transconductance(gm),gate voltage swing(GVS),subthreshold current,gate leakage current,pulsed I-V characteristics,breakdown voltage,cut-off frequency(f_(T)),and maximum oscillation frequency(f_(max)) are investigated.The results show that the double-notch structure HEMT has a 30% improvement of gate voltage swing,a 42.2% improvement of breakdown voltage,and a 9% improvement of cut-off frequency compared with the conventional HEMT.The notch structure also has a good suppression of the current collapse.展开更多
Metabolic changes play a crucial role in determining the status and function of macrophages,but how lipid reprogramming in macrophages contributes to tumor progression is not yet fully understood.Here,we investigated ...Metabolic changes play a crucial role in determining the status and function of macrophages,but how lipid reprogramming in macrophages contributes to tumor progression is not yet fully understood.Here,we investigated the phenotype,contribution,and regulatory mechanisms of lipid droplet(LD)-laden macrophages(LLMs)in hepatocellular carcinoma(HCC).Enriched LLMs were found in tumor tissues and were associated with disease progression in HCC patients.The LLMs displayed immunosuppressive phenotypes(with extensive expression of TREM2,PD-L1,CD206,and CD163)and attenuated the antitumor activities of CD8^(+)T cells.Mechanistically,tumor-induced reshuffling of cellular lipids and TNFα-mediated uptake of tumoral fatty acids contribute to the generation of triglycerides and LDs in macrophages.LDs prolong LLM survival and promote CCL20 secretion,which further recruits CCR6^(+)Tregs to HCC tissue.Inhibiting LLM formation by targeting DGAT1 and DGAT2,which catalyze the synthesis of triglycerides,significantly reduced Treg recruitment,and delayed tumor growth in a mouse hepatic tumor model.Our results reveal the suppressive phenotypes and mechanisms of LLM enrichment in HCC and suggest the therapeutic potential of targeting LLMs for HCC patients.展开更多
Traditional theoretical and empirical calculation methods can guide the design of β-and metastable β-alloys for bio-titanium. However, it is still difficult to obtain novel near-β-Ti alloys with low modulus. This s...Traditional theoretical and empirical calculation methods can guide the design of β-and metastable β-alloys for bio-titanium. However, it is still difficult to obtain novel near-β-Ti alloys with low modulus. This study developed a method that combines machine learning with calculation of phase diagrams(CALPHAD) to facilitate the design of near-β-Ti alloys. An elastic modulus database of Ti–Nb–Zr–Mo–Ta–Sn system was constructed first, and then three features(the electron to atom ratio, mean absolute deviation of atom mass, and mean electronegativity) were selected as the key factors of modulus by performing a three-step feature selection. With these features, a highly accurate model was built for predicting the modulus of near-β-Ti alloys. To further ensure the accuracy of modulus prediction, machine learning with the elastic constants calculated was leveraged by CALPHAD database. The root mean square error of the well-trained model can be as low as 6.75 GPa. Guided by the prediction of machine learning and CALPHAD, three novel near-β-Ti alloys with elastic modulus below 50 GPa were successfully designed in this study. The best candidate alloy(Ti–26Nb–4Zr–4Sn–1Mo–Ta) exhibits an ultra-low modulus(36.6 GPa) after cold rolling with a thickness reduction of 20%. Our method can greatly save time and resources in the development of novel Ti alloys, and experimental verifications have demonstrated the reliability of this method.展开更多
The Permian Fengcheng Formation of the Western Junggar region in the Southwestern Central Asian Orogenic Belt(CAOB)represents one of Earth’s oldest alkali lake deposits.Here,we present a comprehensive study of the st...The Permian Fengcheng Formation of the Western Junggar region in the Southwestern Central Asian Orogenic Belt(CAOB)represents one of Earth’s oldest alkali lake deposits.Here,we present a comprehensive study of the stratigraphy,petrography,two-dimensional seismic data,U–Pb geochronology,and Hf isotope analysis of detrital zircons of this deposit.The results,in conjunction with published data,reflect the tectonic evolution of southwestern CAOB.The ages of detrital zircons indicate that the Fengcheng Formation deposition is inferred to have concluded the early Permian Kungurian.The Hf isotopes of detrital zircons indicate that the detritus for the Fengcheng Formation was derived from upper crustal magmatic sources.The West Junggar Basin preserves the records of three Paleozoic tectonic stages.The first stage occurred in the Early Paleozoic and involved intraoceanic subduction and arc-continent collision.The second stage involved the Carboniferous closure of the Junggar Ocean following successive filling of oceanic basins.The final stage occurred in the Early Permian and was related to intracontinental rifting and tectonic inversion.The results of comparing the comprehensive data of U–Pb ages and Hf isotopes of 2537 zircons from West Junggar,Tianshan and Altay show that the orogenic belts to the south of the CAOB experienced similar plate kinematics and vertical crustal growth in the Paleozoic.展开更多
The end-Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer.Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event.Supervolc...The end-Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer.Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event.Supervolcano eruptions can cause catastrophic effects on global environment,climate,and life.Here we investigate the tuff layers from Early-Middle Triassic boundary in the Yangtze Block and identify a supervolcano eruption event.The zircon U-Pb ages of the section-Langdai,section-Daijiagou and section-Longmendong tuff samples are 247.1±1.9 Ma,247.6±2.0 Ma and 247.7±1.7 Ma,respectively.These ages mark the Olenekian-Anisian boundary.The zircon grains from the tuff layers have negativeεHf(t)(-15.3 to-0.8),two-stage Hf model(TDM2)ages(1.7 to 2.2 Ga)and display high-δ18O values(mostly>10‰).Clay minerals and quartz dominate the rock composition.The whole rock compositions show that the tuff layers were derived from magma of intermediate to felsic composition,which formed by the remelting of Paleoproterozoic materials of continental crust.The volcanic eruption site is located in the Jinshajiang-Ailaoshan-Song Ma suture zone in the southwestern margin of the Yangtze Block.A combination of the closure of the Paleo-Tethys Ocean Basin and the collision of the Indochina Block and South China contributed to the eruption,which was a supervolcano eruption under the active continental margin arc settings.We speculate that this supervolcano eruption might have contributed to the delayed biotic recovery after the end-Permian mass extinction.展开更多
Background:Gut microbiota is pivotal in regulating hosts'biological processes and maintaining homeostasis,but knowledge about its role in wild herbivores in extreme environments remains limited.Methods:Gut bacteri...Background:Gut microbiota is pivotal in regulating hosts'biological processes and maintaining homeostasis,but knowledge about its role in wild herbivores in extreme environments remains limited.Methods:Gut bacteria and fungi were sequenced in ruminant(Chiru and Yak)and nonruminant(Kiang)herbivores on the Qinghai–Tibet Plateau,and their community structure,co-occurrence networks,functions,and assembly mechanisms were investigated using multivariate ecological and statistical methods.Results:Kiang had lower gut microbial diversity than Chiru and Yak.Bacterial host-specific exclusivity was greater than that of fungi.In addition to the evidence of glycan biosynthesis and carbohydrate metabolism,Chiru had a high Firmicutes/Bacteroidetes ratio and low animal pathogen abundance,suggesting better adaptation to the plateau's harsh environment.Additionally,members of gut microbiota tended to co-occur rather than co-exclude in all herbivores.Different network complexity and stability patterns were observed between bacterial and fungal communities.Furthermore,gut bacterial assembly was primarily controlled by stochastic dispersal limitation and drift,whereas fungal assembly was primarily controlled by deterministic homogeneous selection except in Chiru.Conclusions:On the Qinghai–Tibet Plateau,Chiru and Yak exhibit more diverse gut microbiota and more diverse metabolic functions than Kiang,and gut bacteria are more divergent than gut fungi in these herbivores.展开更多
The solidification characteristics and segregation behavior of solute elements Nb,Ni,Mn,Si,Cr and C in 0.3 wt.%Nb-310S steel were investigated using the isothermal solidification quenching experiment and Thermo-Calc c...The solidification characteristics and segregation behavior of solute elements Nb,Ni,Mn,Si,Cr and C in 0.3 wt.%Nb-310S steel were investigated using the isothermal solidification quenching experiment and Thermo-Calc calculation.The phase transformation for 0.3%Nb-310S steel under equilibrium condition can be summarized as follows:liquid(L)→L+γ(1406℃)→γ(1334℃)→γ+NbC(1322℃)→γ+NbC+M_(23)C_(6)(1006℃)→γ+NbC+M_(23)C_(6)→σ(755℃).The results showed that the solidification began with the formation of primary austenite dendrite.The volume fraction of the liquid phase decreased rapidly as the temperature decreased in the initial solidification stage,and then,the liquid phase fraction decreased slowly.When austenite formed,Mn and Ni were enriched in the solid phase,while Nb and C were rejected into the liquid.Nb was present the highest segregation coefficient in 0.3%Nb-310S austenitic stainless steel.The segregation of Nb was the most serious,followed by Mn,Ni and C.Cr and Si exhibited slight segregation during the solidification.The solidification was terminated by the formation of NbC phase.展开更多
In this study, Ce-doped zirconolite was synthesized through high-temperature solid-state reaction at 1250 ℃ in air for 96 h. The crystal phase, microstructure and valence transition were studied by X-ray diffraction ...In this study, Ce-doped zirconolite was synthesized through high-temperature solid-state reaction at 1250 ℃ in air for 96 h. The crystal phase, microstructure and valence transition were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Phase relations of CaZrl xCexTi207 systems were determined by XRD analyses and Rietveld refinements. Four different phases are identified, namely zirconolite, perovskite, pyrochlore, and cerianite. The phase transformation (2M-zirconolite → 4M-zirconolite →Ce-pyrochlore) is caused by cations rearrangement as cerium content increases. The solubility limit of cerium ions in CaZrl .xCexTi207 system is estimated to be approximately 0.80. Under sintering air atmosphere, partial reduction of Ce^4+ in Ce^3+ is detected in Ce 3d XPS soectra, and the ratio of Ce^3+ and Ce^4+ significantly decreases as cerium content increases.展开更多
Background: Paclitaxel (PTX) could inhibit the growth of fibroblasts, which occurs in proliferative cholangitis and leads to biliary stricture. However, its use has been limited due to poor bioavailability and loca...Background: Paclitaxel (PTX) could inhibit the growth of fibroblasts, which occurs in proliferative cholangitis and leads to biliary stricture. However, its use has been limited due to poor bioavailability and local administration for short time. This study designed and synthesized a new PTX-conjugated chitosan film (N-succinyl-hydroxyethyl chitosan containing PTX [PTX-SHEC]) and evaluated its safety and efficiency using in vivo and in vitro experiments. Methods: The SHEC conjugated with PTX was confirmed by nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FT-IR) measurements. Drug releases in vitro and in vivo were determined using high-performance liquid chromatography. Cell viability in vitro was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Rabbit biliary stricture model was constructed. All rabbits randomly divided into five groups (n = 8 in each group): the sham-operated rabbits were used as control (Group A), Groups B received laparotomies and suture, Group C received laparotomies and covered SHEC suture without the PTX coating, Group D received laparotomies and covered PTX-SHEC suture, and Group E received laparotomies and 1000 μmol/L PTX administration. Liver function tests and residual dosage of PTX from each group were measured by enzyme-linked immunosorbent assay. Histological data and a-smooth muscle actin (SMA) immunohistochemical staining of common bile duct were examined. Results: NMR and FT-1R indicated that PTX was successfully introduced, based on the appearance of signals at 7.41-7.99 ppm, 1.50 ppm, and 1.03 ppm, due to the presence of aromatic protons, methylene protons, and methyl protons of PTX, respectively. No bile leak was observed. The PTX-conjugated film could slowly release PTX for 4 weeks (8.89 ± 0.03/ag at day 30). The in vitro cell viability test revealed significantly different levels of toxicity between films with and without PTX ([ 11.7± 4.0% vs. 68. l±6.0%, P 〈 0.001 ), whereas no statistically significant difference was observed among the three sets of PTX-contained films (67.7 ± 5.4%, 67.2±3.4%, and 59.1± 6.0%, P 〉 0.05). Histological examinations revealed that after 28 days of implantment, Groups D and E (but not Group C) had less granulation tissue and glandular hyperplasia in the site ofbiliary duct injury than Group B. The pattern was more obvious in Group D than Group E. Less α-SMA-positive cells were found in tissue from Groups D and E. Comparing with Group E, the liver function was improved significantly in Group D, including total bilirubin (2.69± 1.03 μmol/L vs. 0.81 ± 0.54 μmol/L, P = 0.014), alanine aminotransferase (87.13 ± 17.51 U/L vs. 42.12 ± 15.76 U/L, P = 0.012), and alkaline phosphatase (60.61± 12.31 U/L vs. 40.59 ± 8.78 U/L, P 〈 0.001). Conclusions: PTX-SHEC film effectively inhibites the myofibroblast proliferation and extracellular matrix over-deposition during the healing process of biliary reconstruction. This original film might offer a new way for reducing the occurrence of the benign biliary stricture.展开更多
基金support from several sources,including the Backbone Teacher Training Program(10912-SJGG2021-04233)the Teaching Reform Project of Chengdu University of Technology(JG2130131)+1 种基金the University-Industry Collaborative Education Project,Ministry of Education,China(22097130210756)National Natural Science Foundation of China(42272129).
文摘The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,west of the Baimashan granitic batholith.In order to discern the characteristics of the ore-formingfluids,the underlying mineralization processes,and establish a foundation for the origin of the Yueguang gold depositfluid inclusion micro-thermometry,as well as quartz hydrogen and oxygen isotope analysis,have been carried out on samples obtained from various stages of mineralization.The hydrothermal miner-alization stages within the Yueguang gold deposit can be categorized into three stages:(i)the barren,pre-ore quartz-pyrite stage(Stage Ⅰ),the quartz-pyrite-gold stage(Stage Ⅱ),and the post-ore quartz-carbonate stage(Stage Ⅲ),with the second stage being the main mineralization stage.Thefluid inclusions identified in samples from the main min-eralization stage can predominantly be described with the NaCl–H_(2)O and CO_(2)–NaCl–H_(2)O systems.These inclusions display homogenization temperatures ranging from 158.8 to 334.9℃,and thefluid salinity ranges from 0.3%to 4.0%(wt.%NaCl equiv.).Laser Raman spectroscopy analysis of individual inclusions further reveals the presence of gas-phases such as CO_(2),CH_(4),and N_(2).Isotopic analysis indicatesδ^(18)Ofluid values ranging from 3.95 to 6.7‰ and δDH_(2)O values ranging from-71.9 to-55.7‰.These results indi-cate that the ore-formingfluid of the Yueguang gold deposit belongs to metamorphic hydrothermalfluids of middle-low temperature and low salinity.In the process of ore formation,gold is transported in the form of Au(HS)2-complexes,with gold deposition being driven byfluid immiscibility.Therefore,the Yueguang gold deposit is categorized as an orogenic gold deposit dominated by metamorphic hydrother-malfluid.It may become a new target for gold exploration in the Baimashan region,central Hunan Province.
基金Supported by The Yunnan Medical Discipline Leader Training Program,No.D-2019012.
文摘BACKGROUND Gallstones are common lesions that often require surgical intervention.Laparo-scopic cholecystectomy is the treatment of choice for symptomatic gallstones.Preoperatively,the anatomical morphology of the cystic duct(CD),needs to be accurately recognized,especially when anatomical variations occur in the CD,which is otherwise prone to bile duct injury.However,at present,there is no optimal classification system for CD morphology applicable in clinical practice,and the relationship between anatomical variations in CDs and gallstones remains to be explored.AIM To create a more comprehensive clinically applicable classification of the morphology of CD and to explore the correlations between anatomic variants of CD and gallstones.METHODS A total of 300 patients were retrospectively enrolled from October 2021 to January 2022.The patients were divided into two groups:The gallstone group and the nongallstone group.Relevant clinical data and anatomical data of the CD based on magnetic resonance cholangiopancreatography(MRCP)were collected and analyzed to propose a morphological classification system of the CD and to explore its relationship with gallstones.Multivariate analysis was performed using logistic regression analyses to identify the independent risk factors using variables that were significant in the univariate analysis.RESULTS Of the 300 patients enrolled in this study,200(66.7%)had gallstones.The mean age was 48.10±13.30 years,142(47.3%)were male,and 158(52.7%)were female.A total of 55.7%of the patients had a body mass index(BMI)≥24 kg/m2.Based on the MRCP,the CD anatomical typology is divided into four types:Type I:Linear,type II:n-shaped,type III:S-shaped,and type IV:W-shaped.Univariate analysis revealed differences between the gallstone and nongallstone groups in relation to sex,BMI,cholesterol,triglycerides,morphology of CD,site of CD insertion into the extrahepatic bile duct,length of CD,and angle between the common hepatic duct and CD.According to the multivariate analysis,female,BMI(≥24 kg/m2),and CD morphology[n-shaped:Odds ratio(OR)=10.97,95%confidence interval(95%CI):5.22-23.07,P<0.001;S-shaped:OR=4.43,95%CI:1.64-11.95,P=0.003;W-shaped:OR=7.74,95%CI:1.88-31.78,P=0.005]were significantly associated with gallstones.CONCLUSION The present study details the morphological variation in the CD and confirms that CD tortuosity is an independent risk factor for gallstones.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41872109 and 41702108)China Postdoctoral Science Foundation(Grant No.2019M650833)Everest Scientific Research Program of Chengdu University of Technology。
文摘The Upper Carboniferous Benxi Formation of the Ordos Basin is the lowest strata overlying Middle Ordovician above the major ca.150-Myr sedimentary gap that characterizes the entire North China Block(NCB).We apply an integrated analysis of stratigraphy,petrography,and U-Pb dates and Hf isotopes on detrital zircons to investigate its provenance and relationships to the progressive collisions that formed the Xing’an-Mongolia Orogenic Belt to the north and the Qinling Orogenic Belt to the south.The results show that,in addition to regional patterns of siliciclastic influx from these new uplifted sources,the Benxi Formation is composed of two sequences corresponding to long-term glacial-interglacial cycles during the Moscovian to lower Gzhelian stages which drove global changes of eustatic sea level and weathering.The spatio-temporal distribution of sediment isopachs and facies indicate there were two sediment-infilling pulses,during which the southern and the northern Ordos Basin developed tidal-reworked deltas.The age spectra from detrital zircons,trace element patterns and εNd(t)values reveal that the siliciclastics forming the southern delta was sourced in the Qinling Orogenic Belt,whereas the northern delta was derived from the Xing’an-Mongolia Orogenic Belt.The source-to-sink evolution of this Upper Paleozoic system records the progressive development of orogenic belts and uplifts forming on the southern and northern margins of the NCB prior to its collisions with the South China and the Siberian plates,respectively.
基金funded by Geological Survey Program of China Geological Survey(DD20190816,DD20160057,DD20190606).
文摘Fluorite is one of the important mineral raw materials in the industry.In China,it is mainly distributed in the provinces and regions such as Hunan,Zhejiang,Jiangxi,Inner Mongolia,Fujian,and Henan provinces,boasting huge reserves and large numbers of deposits.However,most of the fluorite deposits are on a small or medium scale.The main fluorite deposits in China were studied in this paper.Their geological features and metallogenic regularity were summarized and compared.Meanwhile,based on their main genetic factors including metallogenic fluid sources and main metallogenic geological processes,they were divided into two groups,namely meso-epithermal deposits and magmatic-hydrothermal deposits.Furthermore,based on the prospecting achievements and research progress obtained in fluorite deposits in recent years,prospecting potential predictions were made for the metallogenic prospect areas and major prospecting areas of fluorite in China.This aims to provide a theoretical basis and direction for future fluorite prospecting in China.
基金The Everest Scientific Research Program of Chengdu University of Technology, China financially supported this study
文摘Numerous intrusive bodies of mafic–ultramafic to felsic compositions are exposed in association with volcanic rocks in the Late Permian Emeishan large igneous province(ELIP),southwestern China.Most of the granitic rocks in the ELIP were derived by differentiation of basaltic magmas with a mantle connection,and crustal magmas have rarely been studied.Here we investigate a suite of mafic dykes and Ⅰ-type granites that yield zircon U-Pb emplacement ages of 259.9±1.2 Ma and 259.3±1.3 Ma,respectively.The εHf(t)values of zircon from the DZ mafic dyke are–0.3 to 9.4,and their corresponding TDM1 values are in the range of 919–523 Ma.The εHf(t)values of zircon from the DSC Ⅰ-type granite are between–1 and 3,with TDM1 values showing a range of 938–782 Ma.We also present zircon O isotope data on crust-derived felsic intrusions from the ELIP for the first time.The δ18O values of zircon from the DSC Ⅰ-type granite ranges from 4.87‰to 7.5‰.The field,petrologic,geochemical and isotopic data from our study lead to the following salient findings.(i)The geochronological study of mafic and felsic intrusive rocks in the ELIP shows that the ages of mafic and felsic magmatism are similar.(ii)The DZ mafic dyke and high-Ti basalts have the same source,i.e.,the Emeishan mantle plume.The mafic dyke formed from magmas sourced at the transitional depth between from garnet-lherzolite and spinel-lherzolite,with low degree partial melting(<10%).(iii)The Hf-O isotope data suggest that the DSC Ⅰ-type granite was formed by partial melting of Neoproterozoic juvenile crust and was contaminated by minor volumes of chemically weathered ancient crustal material.(iv)The heat source leading to the formation of the crust-derived felsic rocks in of the ELIP is considered to be mafic–ultramafic magmas generated by a mantle plume,which partially melted the overlying crust,generating the felsic magma.
基金supported jointly by the National Natural Science Foundation of China(Grant No.41502347)the Young Scholars development fund of SWPU(Grant No.201499010028)+2 种基金the Research Program for the Education Department of Sichuan Province(Grant No.16ZB0087)the Research Program for the Education Department of Sichuan Province(Grant No.15ZB0073)the"Innovative Research Teams at the Local University of Sichuan Province"(Grant No.13TD0008)
文摘The Early Cretaceous granitoids that are widespread in the Tengchong terrane of Southwest China play a critical role in understanding the tectonic framework associated with the Tethyan oceans. In this study, we present a detailed description of zircon U-Pb ages, whole-rock geochemistry and Hf isotopes for the Laoxiangkeng pluton in the eastern Tengchong terrane and elucidate their petrogenesis and geodynamic implications. Zircon U-Pb dating of the Laoxiangkeng pluton yields ages of 114 ± 1 Ma and 115 ± 1 Ma,which imply an Early Cretaceous magmatic event. The Laoxiangkeng pluton enriched in Si and Na, is calcalkaline and metaluminous, and has the characteristics of highly fractionated I-type granites. Zircons from the pluton have calculated ε_(Hf)(t) values of-12.7 to-3.7 and two-stage model ages of 1327-1974 Ma,respectively, indicating a mixed source of partial melting of Paleo-Neoproterozoic crust-derived compositions with some inputs of mantle-derived magmas. By integrating all available data for the regional tectonic evolution of the eastern Tethys tectonic domain, we conclude that the Early Cretaceous magmatism in the Tengchong terrane was produced by the northeastward subduction of the Meso-Tethyan Bangong-Nujiang Ocean.
基金VI. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China ((No.20973067) and Guangdong-Natural Science Foundation (No.7005823), the Scientific Research Foundation for the Returned Overseas Chinese scholars, the State Education Ministry and the Foundation for Introduction of Talents by the Universities in Guangdong Province. Initial computation contributed by Mr. Xiting Zhang is gratefully acknowledged.
文摘Density functional theory (DFT) calculations are reported for the structures of neutral and zwitterionic glycine-(CHaOH)n where n=1-6. Initial geometries of the clusters of neutral and zwitterionic glycine with 1-6 methanol molecules are fully optimized at B3LYP/6-31+G^* level of theory. The lowest energy configurations are located and their hydrogen bond structures are analyzed. Theoretical prediction reveals that the methanols prefer to locate near the carboxylic acid group for the small clusters (n_〈3) with the neutral form while the configurations with the methanols bridging the acid and the amino group are favorite in the zwitterionic form clusters. When the number of the methanol molecules in the clusters reaches five and six, the two forms tend to be isoenergetic.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61974108 and 61674117)the National Natural Science Foundation for Young Scholars of China(Grants No.61804119)the Postdoctoral Science Foundation of China(Grants No.2018M643576)。
文摘A GaN-based high electron mobility transistor(HEMT)with p-GaN islands buried layer(PIBL)for terahertz applications is proposed.The introduction of a p-GaN island redistributes the electric field in the gate–drain channel region,thereby promoting the formation of electronic domains in the two-dimensional electron gas(2DEG)channel.The formation and regulation mechanism of the electronic domains in the device are investigated using Silvaco-TCAD software.Simulation results show that the 0.2µm gate HEMT with a PIBL structure having a p-GaN island doping concentration(Np)of 2.5×10^(18)cm^(−3)–3×10^(18)cm^(−3)can generate stable oscillations up to 344 GHz–400 GHz under the gate–source voltage(V_(gs))of 0.6 V.As the distance(D_(p))between the p-GaN island and the heterojunction interface increases from 5 nm to 15 nm,the fundamental frequency decreases from 377 GHz to 344 GHz,as well as the ratio of oscillation current amplitude of the fundamental component to the average component I_(f1)/I_(avg) ranging from 2.4%to 3.84%.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61674117 and 61974108)the State Key Discipline Laboratory of Wide Bandgap Semiconductor Technology of Xidian University,China。
文摘The effects of various notch structures on direct current(DC) and radio frequency(RF) performances of AlGaN/GaN high electron mobility transistors(HEMTs) are analyzed.The AlGaN/GaN HEMTs,each with a 0.8-μm gate length,50-μm gate width,and 3-μm source-drain distance in various notch structures at the AlGaN/GaN barrier layer,are manufactured to achieve the desired DC and RF characteristics.The maximum drain current(I_(ds,max)),pinch-off voltage(V_(th)),maximum transconductance(gm),gate voltage swing(GVS),subthreshold current,gate leakage current,pulsed I-V characteristics,breakdown voltage,cut-off frequency(f_(T)),and maximum oscillation frequency(f_(max)) are investigated.The results show that the double-notch structure HEMT has a 30% improvement of gate voltage swing,a 42.2% improvement of breakdown voltage,and a 9% improvement of cut-off frequency compared with the conventional HEMT.The notch structure also has a good suppression of the current collapse.
基金supported by project grants from the National Key R&D Program of China(2023YFA0915703)the Guangdong Basic and Applied Basic Research Foundation(2022A1515111205)+1 种基金the National Natural Science Foundation of China(32230034,82273296)the Open Fund Project of Guangdong Academy of Medical Sciences(YKY-KF202207).
文摘Metabolic changes play a crucial role in determining the status and function of macrophages,but how lipid reprogramming in macrophages contributes to tumor progression is not yet fully understood.Here,we investigated the phenotype,contribution,and regulatory mechanisms of lipid droplet(LD)-laden macrophages(LLMs)in hepatocellular carcinoma(HCC).Enriched LLMs were found in tumor tissues and were associated with disease progression in HCC patients.The LLMs displayed immunosuppressive phenotypes(with extensive expression of TREM2,PD-L1,CD206,and CD163)and attenuated the antitumor activities of CD8^(+)T cells.Mechanistically,tumor-induced reshuffling of cellular lipids and TNFα-mediated uptake of tumoral fatty acids contribute to the generation of triglycerides and LDs in macrophages.LDs prolong LLM survival and promote CCL20 secretion,which further recruits CCR6^(+)Tregs to HCC tissue.Inhibiting LLM formation by targeting DGAT1 and DGAT2,which catalyze the synthesis of triglycerides,significantly reduced Treg recruitment,and delayed tumor growth in a mouse hepatic tumor model.Our results reveal the suppressive phenotypes and mechanisms of LLM enrichment in HCC and suggest the therapeutic potential of targeting LLMs for HCC patients.
基金financially supported by the National Natural Science Foundation of China (No.52071339)the Natural Science Foundation of Hunan Province,China (No.2020JJ4739)Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China (No.201009-K)。
文摘Traditional theoretical and empirical calculation methods can guide the design of β-and metastable β-alloys for bio-titanium. However, it is still difficult to obtain novel near-β-Ti alloys with low modulus. This study developed a method that combines machine learning with calculation of phase diagrams(CALPHAD) to facilitate the design of near-β-Ti alloys. An elastic modulus database of Ti–Nb–Zr–Mo–Ta–Sn system was constructed first, and then three features(the electron to atom ratio, mean absolute deviation of atom mass, and mean electronegativity) were selected as the key factors of modulus by performing a three-step feature selection. With these features, a highly accurate model was built for predicting the modulus of near-β-Ti alloys. To further ensure the accuracy of modulus prediction, machine learning with the elastic constants calculated was leveraged by CALPHAD database. The root mean square error of the well-trained model can be as low as 6.75 GPa. Guided by the prediction of machine learning and CALPHAD, three novel near-β-Ti alloys with elastic modulus below 50 GPa were successfully designed in this study. The best candidate alloy(Ti–26Nb–4Zr–4Sn–1Mo–Ta) exhibits an ultra-low modulus(36.6 GPa) after cold rolling with a thickness reduction of 20%. Our method can greatly save time and resources in the development of novel Ti alloys, and experimental verifications have demonstrated the reliability of this method.
基金supported by the funding of the National Natural Science Foundation of China(Nos.41802177,42272188)Petrochina Technology Project(Nos.2021DJ0206,2022DJ0507,2020D-5008-04).
文摘The Permian Fengcheng Formation of the Western Junggar region in the Southwestern Central Asian Orogenic Belt(CAOB)represents one of Earth’s oldest alkali lake deposits.Here,we present a comprehensive study of the stratigraphy,petrography,two-dimensional seismic data,U–Pb geochronology,and Hf isotope analysis of detrital zircons of this deposit.The results,in conjunction with published data,reflect the tectonic evolution of southwestern CAOB.The ages of detrital zircons indicate that the Fengcheng Formation deposition is inferred to have concluded the early Permian Kungurian.The Hf isotopes of detrital zircons indicate that the detritus for the Fengcheng Formation was derived from upper crustal magmatic sources.The West Junggar Basin preserves the records of three Paleozoic tectonic stages.The first stage occurred in the Early Paleozoic and involved intraoceanic subduction and arc-continent collision.The second stage involved the Carboniferous closure of the Junggar Ocean following successive filling of oceanic basins.The final stage occurred in the Early Permian and was related to intracontinental rifting and tectonic inversion.The results of comparing the comprehensive data of U–Pb ages and Hf isotopes of 2537 zircons from West Junggar,Tianshan and Altay show that the orogenic belts to the south of the CAOB experienced similar plate kinematics and vertical crustal growth in the Paleozoic.
基金supported by the National Natural Science Foundation of China[grant number 42272129]Outstanding Youth Science Fund Project of Sichuan Province,China[grant number 23NSFJQ0162]+1 种基金Department of Natural Resources of Sichuan Province,China[grant number KJ-2023-011]the Everest Scientific Research Program of Chengdu University of Technology.
文摘The end-Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer.Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event.Supervolcano eruptions can cause catastrophic effects on global environment,climate,and life.Here we investigate the tuff layers from Early-Middle Triassic boundary in the Yangtze Block and identify a supervolcano eruption event.The zircon U-Pb ages of the section-Langdai,section-Daijiagou and section-Longmendong tuff samples are 247.1±1.9 Ma,247.6±2.0 Ma and 247.7±1.7 Ma,respectively.These ages mark the Olenekian-Anisian boundary.The zircon grains from the tuff layers have negativeεHf(t)(-15.3 to-0.8),two-stage Hf model(TDM2)ages(1.7 to 2.2 Ga)and display high-δ18O values(mostly>10‰).Clay minerals and quartz dominate the rock composition.The whole rock compositions show that the tuff layers were derived from magma of intermediate to felsic composition,which formed by the remelting of Paleoproterozoic materials of continental crust.The volcanic eruption site is located in the Jinshajiang-Ailaoshan-Song Ma suture zone in the southwestern margin of the Yangtze Block.A combination of the closure of the Paleo-Tethys Ocean Basin and the collision of the Indochina Block and South China contributed to the eruption,which was a supervolcano eruption under the active continental margin arc settings.We speculate that this supervolcano eruption might have contributed to the delayed biotic recovery after the end-Permian mass extinction.
基金National Natural Science Foundation of China,Grant/Award Numbers:32171580,42101057,32161123002Fundamental Research Funds for the Central Universities of China,Grant/Award Number:lzujbky-2021-ey03。
文摘Background:Gut microbiota is pivotal in regulating hosts'biological processes and maintaining homeostasis,but knowledge about its role in wild herbivores in extreme environments remains limited.Methods:Gut bacteria and fungi were sequenced in ruminant(Chiru and Yak)and nonruminant(Kiang)herbivores on the Qinghai–Tibet Plateau,and their community structure,co-occurrence networks,functions,and assembly mechanisms were investigated using multivariate ecological and statistical methods.Results:Kiang had lower gut microbial diversity than Chiru and Yak.Bacterial host-specific exclusivity was greater than that of fungi.In addition to the evidence of glycan biosynthesis and carbohydrate metabolism,Chiru had a high Firmicutes/Bacteroidetes ratio and low animal pathogen abundance,suggesting better adaptation to the plateau's harsh environment.Additionally,members of gut microbiota tended to co-occur rather than co-exclude in all herbivores.Different network complexity and stability patterns were observed between bacterial and fungal communities.Furthermore,gut bacterial assembly was primarily controlled by stochastic dispersal limitation and drift,whereas fungal assembly was primarily controlled by deterministic homogeneous selection except in Chiru.Conclusions:On the Qinghai–Tibet Plateau,Chiru and Yak exhibit more diverse gut microbiota and more diverse metabolic functions than Kiang,and gut bacteria are more divergent than gut fungi in these herbivores.
基金supported by Shanghai Agriculture Applied Technology Development Program of China(2019-02-08-00-08F01124)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(51521004)the National Natural Science Foundation of China(52036002)。
基金supported by Joint Fund of National Natural Science Foundation of China and Liaoning Province (No.U1708252)Industrial Strong Foundation Project (TC190A4DA/35)the Scientific Research Project of China Three Gorges Corporation (No.JD-YJ-05006).
文摘The solidification characteristics and segregation behavior of solute elements Nb,Ni,Mn,Si,Cr and C in 0.3 wt.%Nb-310S steel were investigated using the isothermal solidification quenching experiment and Thermo-Calc calculation.The phase transformation for 0.3%Nb-310S steel under equilibrium condition can be summarized as follows:liquid(L)→L+γ(1406℃)→γ(1334℃)→γ+NbC(1322℃)→γ+NbC+M_(23)C_(6)(1006℃)→γ+NbC+M_(23)C_(6)→σ(755℃).The results showed that the solidification began with the formation of primary austenite dendrite.The volume fraction of the liquid phase decreased rapidly as the temperature decreased in the initial solidification stage,and then,the liquid phase fraction decreased slowly.When austenite formed,Mn and Ni were enriched in the solid phase,while Nb and C were rejected into the liquid.Nb was present the highest segregation coefficient in 0.3%Nb-310S austenitic stainless steel.The segregation of Nb was the most serious,followed by Mn,Ni and C.Cr and Si exhibited slight segregation during the solidification.The solidification was terminated by the formation of NbC phase.
基金Project supported by Foundation of Laboratory of National Defense Key Discipline for Nuclear Waste and Environmental Safety,Southwest University of Science and Technology(15yyhk16,17LZX606)National Natural Science Foundation of China(41302027)+3 种基金973 project(2014CB8460003)One-Thousand-Talents Scheme in Sichuan ProvinceHebei Outstanding Young ScholarsScience and Technology Program of Hebei Province(D2016403064,160446012 and 15211121)
文摘In this study, Ce-doped zirconolite was synthesized through high-temperature solid-state reaction at 1250 ℃ in air for 96 h. The crystal phase, microstructure and valence transition were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Phase relations of CaZrl xCexTi207 systems were determined by XRD analyses and Rietveld refinements. Four different phases are identified, namely zirconolite, perovskite, pyrochlore, and cerianite. The phase transformation (2M-zirconolite → 4M-zirconolite →Ce-pyrochlore) is caused by cations rearrangement as cerium content increases. The solubility limit of cerium ions in CaZrl .xCexTi207 system is estimated to be approximately 0.80. Under sintering air atmosphere, partial reduction of Ce^4+ in Ce^3+ is detected in Ce 3d XPS soectra, and the ratio of Ce^3+ and Ce^4+ significantly decreases as cerium content increases.
基金This work was supported by grants from the National Natural Science Foundation of China (No. 81260084) and the Applied Basic Research Project in Yunnan Province (No. 2011 fb162).
文摘Background: Paclitaxel (PTX) could inhibit the growth of fibroblasts, which occurs in proliferative cholangitis and leads to biliary stricture. However, its use has been limited due to poor bioavailability and local administration for short time. This study designed and synthesized a new PTX-conjugated chitosan film (N-succinyl-hydroxyethyl chitosan containing PTX [PTX-SHEC]) and evaluated its safety and efficiency using in vivo and in vitro experiments. Methods: The SHEC conjugated with PTX was confirmed by nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FT-IR) measurements. Drug releases in vitro and in vivo were determined using high-performance liquid chromatography. Cell viability in vitro was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Rabbit biliary stricture model was constructed. All rabbits randomly divided into five groups (n = 8 in each group): the sham-operated rabbits were used as control (Group A), Groups B received laparotomies and suture, Group C received laparotomies and covered SHEC suture without the PTX coating, Group D received laparotomies and covered PTX-SHEC suture, and Group E received laparotomies and 1000 μmol/L PTX administration. Liver function tests and residual dosage of PTX from each group were measured by enzyme-linked immunosorbent assay. Histological data and a-smooth muscle actin (SMA) immunohistochemical staining of common bile duct were examined. Results: NMR and FT-1R indicated that PTX was successfully introduced, based on the appearance of signals at 7.41-7.99 ppm, 1.50 ppm, and 1.03 ppm, due to the presence of aromatic protons, methylene protons, and methyl protons of PTX, respectively. No bile leak was observed. The PTX-conjugated film could slowly release PTX for 4 weeks (8.89 ± 0.03/ag at day 30). The in vitro cell viability test revealed significantly different levels of toxicity between films with and without PTX ([ 11.7± 4.0% vs. 68. l±6.0%, P 〈 0.001 ), whereas no statistically significant difference was observed among the three sets of PTX-contained films (67.7 ± 5.4%, 67.2±3.4%, and 59.1± 6.0%, P 〉 0.05). Histological examinations revealed that after 28 days of implantment, Groups D and E (but not Group C) had less granulation tissue and glandular hyperplasia in the site ofbiliary duct injury than Group B. The pattern was more obvious in Group D than Group E. Less α-SMA-positive cells were found in tissue from Groups D and E. Comparing with Group E, the liver function was improved significantly in Group D, including total bilirubin (2.69± 1.03 μmol/L vs. 0.81 ± 0.54 μmol/L, P = 0.014), alanine aminotransferase (87.13 ± 17.51 U/L vs. 42.12 ± 15.76 U/L, P = 0.012), and alkaline phosphatase (60.61± 12.31 U/L vs. 40.59 ± 8.78 U/L, P 〈 0.001). Conclusions: PTX-SHEC film effectively inhibites the myofibroblast proliferation and extracellular matrix over-deposition during the healing process of biliary reconstruction. This original film might offer a new way for reducing the occurrence of the benign biliary stricture.