Background:Immunosuppression compromises the host’s ability to combat pathogens,thereby increasing susceptibility to multisystem disorders.However,safe and effective curative treatments for this condition are current...Background:Immunosuppression compromises the host’s ability to combat pathogens,thereby increasing susceptibility to multisystem disorders.However,safe and effective curative treatments for this condition are currently lacking.Modulating the gut microbiota and their metabolites represents a promising therapeutic strategy.Notably,the Chinese herbal compound Yunzhi Guben Gao(YZG)has demonstrated multi-target immunomodulatory potential.Methods:A mouse model of dexamethasone-induced immunosuppression was employed to evaluate the effects of YZG.Immune organ indices(thymus,spleen),serum cytokine levels(IL-2,TNF-α),mucosal immunity markers(pulmonary/colonic SIgA),gut microbiota structure,and short-chain fatty acids(SCFAs)abundance were evaluated.Key microbial genera and metabolites were identified via Spearman correlation analysis.Pseudo-germ-free model mice established via quadruple antibiotic treatment combined with isovaleric acid intervention were employed to evaluate whether YZG efficacy depends on the intestinal microbiota and its metabolites,and whether its intrinsic mechanisms involve the promotion of isovaleric acid production.Results:YZG intervention ameliorated systemic and mucosal immune function in immunosuppressed mice.Mechanistically,YZG remodeled gut microbiota structure and significantly increased SCFAs levels.Notably,the abundance of the genus Ligilactobacillus exhibited the strongest positive correlation with isovaleric acid levels.Ligilactobacillus abundance was also positively correlated with immune-enhancing parameters and negatively correlated with the proinflammatory cytokine TNF-α,suggesting that Ligilactobacillus plays a pivotal role in the YZG regulatory network.Experiments using pseudo-germ-free mice and isovaleric acid intervention further demonstrated that the immunoprotective effects of YZG are closely related to intestinal microbiota remodeling and increased isovaleric acid production.Conclusion:YZG alleviates immunosuppression through multiple mechanisms,primarily involving the enrichment of the probiotic genus Ligilactobacillus and the consequent increase in isovaleric acid production.This process coordinately modulates mucosal immunity,cytokine networks,and immune organ function.The elucidation of this“microbiota-metabolite-immunity”axis provides both a pharmacological basis for the clinical application of YZG and novel immune-restorative strategies targeting gut microecological regulation.展开更多
Early multiwavelength observations offer crucial insights into the nature of the relativistic jets responsible for gamma-ray bursts and their interaction with the surrounding medium.We present data of GRB 240825A from...Early multiwavelength observations offer crucial insights into the nature of the relativistic jets responsible for gamma-ray bursts and their interaction with the surrounding medium.We present data of GRB 240825A from 17 space-and ground-based telescopes/instruments,covering wavelengths from NIR/optical to X-ray and GeV,and spanning from the prompt emission to the afterglow phase triggered by Swift and Fermi.The early afterglow observations were carried out by SVOM/C-GFT,and spectroscopic observations of the afterglow by GTC,VLT,and TNG determined the redshift of the burst(z=0.659)later.A comprehensive analysis of the prompt emission spectrum observed by Swift-BAT and Fermi-GBM/LAT reveals a rare and significant high-energy cutoff at 76 MeV.Assuming this cutoff is due toγγabsorption allows us to place an upper limit on the initial Lorentz factor,Γ_(0)<245.The optical/NIR and GeV afterglow light curves can be described by the standard external shock model,with early-time emission dominated by a reverse shock(RS)and a subsequent transition to forward shock(FS)emission.Our afterglow modeling yields a consistent estimate of the initial Lorentz factor(Γ_(0)∼234).Furthermore,the RS-to-FS magnetic field ratio(R 302B)indicates that the RS region is significantly more magnetized than the FS region.An isotropic-equivalent kinetic energy of E_(k,iso)=5.25×10^(54) erg is derived,and the correspondingγ-ray radiation efficiency is estimated to beη_(γ)=3.1%.On the other hand,the standard afterglow model cannot reproduce the X-ray light curve of GRB 240825A,calling for improved models to characterize all multiwavelength data.展开更多
Magnesium(Mg)-based implants have been clinically proven to fulfill long-term service requirements,but their passive degradation periods remain to be uncontrollable.Herein,we developed a novel near infrared(NIR)-respo...Magnesium(Mg)-based implants have been clinically proven to fulfill long-term service requirements,but their passive degradation periods remain to be uncontrollable.Herein,we developed a novel near infrared(NIR)-responsive coating on a Mg-Ag-Mn alloy with controllable biodegradation enhanced by air release.The coating exhibits a bi-layered structure,in which the outer layer consists of polycaprolactone(PCL)with the addition of nano-sized polypyrrole(PPy)particles for NIR response,whereas the inner layer is a porous ceramic film produced via plasma electrolytic oxidation(PEO).In particular,the porous structure of PEO film was proposed as a carrier for entrapped air to form the“air bomb”.Without NIR irradiation,the coating possesses a dense and homogeneous microstructure and exhibits excellent long-term durability in saline.Under the NIR irradiation,the PCL resin transforms from a rubbery state to a viscous state promoted by the photothermal action of PPy,while the thermal-expanded air in PEO film escapes from the PCL resin,resulting in macroscopic defects across the coating.This phenomenon leads to a change in the function of Mg alloy from"anti-corrosion"to"biodegradation".This work is expected to provide a new strategy for optimizing the service time of Mg-based implants.展开更多
The present work investigates the corrosion behaviour of an AA2024 alloy thin wall structure produced by wire arc additive manufacturing(WAAM)with interpass rolling,focussing on the influence of interpass rolling.It i...The present work investigates the corrosion behaviour of an AA2024 alloy thin wall structure produced by wire arc additive manufacturing(WAAM)with interpass rolling,focussing on the influence of interpass rolling.It is found that although interpass rolling does not change the typical configuration of thin wall structure,i.e.melt pool zone(MPZ),melt pool border(MPB)and heat-affected zone(HAZ),the plastic deformation introduced by interpass rolling leads to the variation of grain-stored energy across the structure,which consequently results in the highest corrosion susceptibility of MPB due to its relatively high stored energy.展开更多
Magnesium implants have received widespread attention in orthopaedic surgery.However,the mechanical degradation and concurrent inflammation caused by the rapid corrosion of Mg limits their applications.In this study,a...Magnesium implants have received widespread attention in orthopaedic surgery.However,the mechanical degradation and concurrent inflammation caused by the rapid corrosion of Mg limits their applications.In this study,a kind of unique core-shell heterojunction CuS@PPy nanostructures was synthesized and then incorporated in polycaprolactone(PCL)to construct an intelligent coating(CuS@PPy/PCL)on micro-arc-oxidized Mg implants.The PCL-based coating can realize near-infrared(NIR)-driven antibacterial and controllable Mg dissolution according to different bone healing stages.At the beginning of bone remodelling,the coating exhibits promising antibacterial properties with 99.67%and 99.17%efficacy against S.aureus and E.coli,respectively,thanks to the singlet oxygen(^(1)O_(2))and alkoxyl radicals(RO·)generated by the photodynamic effect of CuS@PPy heterojunction under low-power NIR light(1.5 W/cm^(2)).In the bone reparative stage,the PCL-based coating can maintain high corrosion resistance to meet the mechanical requirements of Mg implants in human body fluid.However,after the complete rehabilitation of bones,through a high-power(2 W/cm^(2))NIR light,the PCL-based coating changed from an elastic to a viscous flow state(44.7℃)under the photothermal effects of CuS@PPy,leading to quick degradation of the PCL-based coating and following accelerating dissolution of the Mg implant(avoiding secondary surgery).Hopefully,this NIR-responsive coating may provide an innovative method for the antibacterial and controllable dissolution of Mg implants.展开更多
The gel-spun ultra-high molecular weight polyethylene （UHMWPE） fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultima...The gel-spun ultra-high molecular weight polyethylene （UHMWPE） fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultimate structure and mechanical properties of UHMWPE fibers for different gel solution concentrations were analyzed by tensile testing, differential scanning calorimetry （DSC）, wide angle X-ray diffraction （WAXD） and small angle X-ray scattering （SAXS）. With the increase of gel solution concentration, the ultimate mechanical properties of UHMWPE fibers were decreased and the crystallization and orientation of UHMWPE fibers became inferior. Besides, both the average shish length （ （Lshsh） ） and shish misorientation （B0） of UHMWPE fibers were decreased with the increase of gel solution concentration. In addition, the appropriate increase of spinning temperature led to the further optimization of the ultimate structure and mechanical properties of UHMWPE fibers.展开更多
AIM To investigate the effect of epigallocatechin gallate(EGCG) on structural changes of gut microbiota in colorectal carcinogenesis.METHODS An azoxymethane(AOM)/dextran sodium sulfate(DSS)-induced colitis mouse model...AIM To investigate the effect of epigallocatechin gallate(EGCG) on structural changes of gut microbiota in colorectal carcinogenesis.METHODS An azoxymethane(AOM)/dextran sodium sulfate(DSS)-induced colitis mouse model was established. Fortytwo female FVB/N mice were randomly divided into the following three groups: group 1(10 mice, negative control) was treated with vehicle, group 2(16 mice, positive control) was treated with AOM plus vehicle, and group 3(16 mice, EG) was treated with AOM plus EGCG. For aberrant crypt foci(ACF) evaluation, the colons were rapidly took out after sacrifice, rinsed with saline, opened longitudinally, laid flat on a polystyrene board, and fixed with 10% buffered formaldehyde solution before being stained with 0.2% methylene blue in saline. For tumor evaluation, the colon was macroscopically inspected and photographed, then the total number of tumors was enumerated and tumor size measured. For histological examination, the fixed tissues were paraffin-embedded and sectioned at 5 mm thickness. Microbial genomic DNA was extracted from fecal and intestinal content samples using a commercial kit. The V4 hypervariable regions of 16 S r RNA were PCR-amplified with the barcoded fusion primers. Using the best hit classification option, the sequences from each sample were aligned to the RDP 16 S r RNA training set to classify the taxonomic abundance in QIIME. Statistical analyses were then performed.RESULTS Treatment of mice with 1% EGCG caused a significant decrease in the mean number of ACF per mouse, when compared with the model mice treated with AOM/DSS(5.38 ± 4.24 vs 13.13 ± 3.02, P < 0.01). Compared with the positive control group, 1% EGCG treatment dependently decreased tumor load per mouse by 85%(33.96 ± 6.10 vs 2.96 ± 2.86, respectively, P < 0.01). All revealed that EGCG could inhibit colon carcinogenesis by decreasing the number of precancerous lesions as well as solid tumors, with reduced tumor load and delayed histological progression of CRC. During the cancerization, the diversity of gut microbiota increased, potential carcinogenic bacteria such as Bacteroides were enriched, and the abundance of butyrate-producing bacteria(Clostridiaceae, Ruminococcus, etc.) decreased continuously. In contrast, the structure of gut microbiota was relatively stable during the intervention of EGCG on colon carcinogenesis. Enrichment of probiotics(Bifidobacterium, Lactobacillu, etc.) might be a potential mechanism for EGCG's effects on tumor suppression. Via bioinformatics analysis, principal coordinate analysis and cluster analysis of the tumor formation process, we found that the diversity of gut microbiota increased in the tumor model group while that in the EGCG interfered group(EG) remained relatively stable.CONCLUSION Gut microbiota imbalance might be a potential mechanism for the prevention of malignant transformation by EGCG, which is significant for diagnosis, treatment, prognosis evaluation, and prevention of colorectal cancer.展开更多
AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant pro...AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant proBFT-2 was expressed in Escherichia coli strain Rosetta (DE3) and BFT-2 was obtained and tested for its biological activity via colorectal adenocarcinoma cell strains SW-480. Seventy C57BL/6J mice were randomly divided into a blank (BC; n = 10), model (AD; n = 20), model + low-dose toxin (ADLT; n = 20, 10 mu g), and a model + high-dose toxin (ADHT; n = 20, 20 mu g) group. Mice weight, tumor formation and pathology were analyzed. Immunohistochemistry determined Ki-67 and Caspase-3 expression in normal and tumor tissues of colorectal mucosa. RESULTS Recombinant BFT-2 was successfully obtained, along with its biological activity. The most obvious weight loss occurred in the AD group compared with the ADLT group (21.82 +/- 0.68 vs 23.23 +/- 0.91, P < 0.05) and the ADHT group (21.82 +/- 0.68 vs 23.57 +/- 1.06, P < 0.05). More tumors were found in the AD group than in the ADLT and ADHT groups (19.75 +/- 3.30 vs 6.50 +/- 1.73, P < 0.05; 19.75 +/- 3.30 vs 6.00 +/- 2.16, P < 0.05). Pathology showed that 12 mice had adenocarcinoma and 6 cases had adenoma in the AD group. Five mice had adenocarcinoma and 15 had adenoma in the ADLT group. Four mice had adenocarcinoma and 16 had adenoma in the ADHT group. The incidence of colorectal adenocarcinoma in both the ADHT group and the ADHT group was reduced compared to that in the AD group (P < 0.05, P < 0.05). The positive rate of Ki-67 in the ADLT group and the ADHT group was 50% and 40%, respectively, both of which were lower than that found in the AD group (94.44%, P < 0.05, P < 0.05). Caspase-3 expression in the ADLT group and the ADHT group was 45% and 55%, both of which were higher than that found in the BC group (16.67%, P < 0.05, P < 0.05). CONCLUSION Oral administration with lower-dose biologically active recombinant BFT-2 inhibited colorectal tumorigenesis in mice.展开更多
The multiple endothermic peaks of poly（3-hydroxybutyrate-co-3-hydroxyvalerate） （P（HB-co-HV）） in differential scanning calorimetry （DSC） results, as one representative phenomenon of polymer with unique cocrysta...The multiple endothermic peaks of poly（3-hydroxybutyrate-co-3-hydroxyvalerate） （P（HB-co-HV）） in differential scanning calorimetry （DSC） results, as one representative phenomenon of polymer with unique cocrystallization behavior, were generally considered as the results of melting/recrystallization. In this study, wide angle X-ray diffraction （WAXD） and small angle X-ray scattering （SAXS） experiments were conducted to analyze the phenomena of multiple endothermic peaks in DSC results. The results of these analyses indicated that the multiple endotherms were mainly caused by different lamellae structures. For P（HB-co-HV） with lower HV content, it was comprised of two structures of HV total exclusion and HV partial inclusion in the crystal lamellae. For P（HB-co-HV） with higher HV content, it was also comprised of two structures of HV total inclusion and HV partial inclusion in the crystal lamellae. However, only structure with HV partial inclusion in the crystal lamellae remained existing after first melting peak for all samples.展开更多
The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize it...The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of Mg-Ag-Mn alloys is investigated with the underlying microstructural factors examined. The Mg-Ag alloy with 2 wt% Mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of Mn results in α-Mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-Mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.展开更多
Ultra-high molecular weight polyethylene（UHMWPE）/chitin nanocrystal（CNC） fibers were prepared. Compared with the pure UHMWPE fibers, the ultimate tensile strength and Young＇s modulus of UHMWPE/CNC fibers are impr...Ultra-high molecular weight polyethylene（UHMWPE）/chitin nanocrystal（CNC） fibers were prepared. Compared with the pure UHMWPE fibers, the ultimate tensile strength and Young＇s modulus of UHMWPE/CNC fibers are improved by 15.7% and 49.6%, respectively, with the addition of chitin nanocrystals（CNCs） of 1 wt%. The melting temperature（Tm） of UHMWPE/CNC fibers was higher than that of pure UHMWPE fibers. Pure UHMWPE fibers and UHMWPE/CNC fibers were characterized with respect to crystallinity, orientation and kebab structure by wide-angle X-ray diffraction（WAXD）, small-angle X-ray scattering（SAXS） and scanning electron microscopy（SEM）. It is found that the CNCs act as the shish structure in UHMWPE/CNC fibers and the kebab crystals are grown around the CNCs. There was almost no difference between pure UHMWPE fibers and UHMWPE/CNC fibers in orientation. But the degree of crystallinity of various stages of UHMWPE/CNC fibers was respectively higher than the corresponding stage of pure UHMWPE fibers. Moreover, the addition of 1 wt% CNCs improved the thickness of kebab crystals and accelerated the transformation of kebab to shish.展开更多
Microbeam wide-angle X-ray diffraction（WAXD） experiments were carried out at different structural knot positions of SIOC and M4 fibers of ultra-high molecular weight polyethylene（UHMWPE）. The optical microscope im...Microbeam wide-angle X-ray diffraction（WAXD） experiments were carried out at different structural knot positions of SIOC and M4 fibers of ultra-high molecular weight polyethylene（UHMWPE）. The optical microscope images revealed that SIOC fiber had bamboo-like structural knots, and M4 fiber had chaotic distribution of structural knots. WAXD patterns showed the monoclinic unit cell in the whole M4 fiber, but different lamellar orientations in the bamboo joint of SIOC fiber. In addition, small-angle X-ray scattering（SAXS） patterns confirmed that the SIOC fiber contained uniform distribution of shish structures, and differential scanning calorimetry（DSC） measurements showed that its less branched and short chains benefited the orthorhombic-hexagonal phase transformation.展开更多
We will introduce the construction and design of a new simultaneous three-channel multicolor CCD photometer.This photometer has been mounted on the 1.2 m telescope at Jilin Astronomical Observatory,and is applied to s...We will introduce the construction and design of a new simultaneous three-channel multicolor CCD photometer.This photometer has been mounted on the 1.2 m telescope at Jilin Astronomical Observatory,and is applied to study space debris,gamma-ray burst afterglows,asteroids and other rapidly variable objects.As one of the ground follow-up telescopes of the Chinese-French Space-based multi-band astronomical Variable Objects Monitor(SVOM)mission,it appears very essential to evaluate the performance of the photometry system of this photometer,which can achieve simultaneous imaging within a field of view of 21’.5×21’.5,21’.5×21’.5 and21’.3×21’.3 in the Sloan Digital Sky Survey(SDSS)g’,r’,i’bands,respectively.Photometric calibrations were carried out by using plenty of SDSS standard stars,and the relationship between the photometric system and the Johnson-Bessel filter system was also studied.The results of the performance evaluation from observing open cluster M67 are presented.展开更多
G-quadruplex ligands have been accepted as potential therapeutic agents for anticancer treatment. Thioflavin T （ThT）, a highly selective G-quadruplex ligand, can bind G-quadruplex with a fluorescent light-up signal ...G-quadruplex ligands have been accepted as potential therapeutic agents for anticancer treatment. Thioflavin T （ThT）, a highly selective G-quadruplex ligand, can bind G-quadruplex with a fluorescent light-up signal change and high specificity against DNA duplex. However, there are still different opinions that ThT induces/stabilizes G-quadruplex foldings/topologies in human telomere sequence. Here, a sensitive single-molecule nanopore technology was utilized to analyze the interactions between human telomeric DNA （Tel DNA） and ThT. Both translocation time and current blockade were measured to investigate the translocation behaviors. Furthermore, the effects of metal ion （K~ and Na~） and pH on the translocation behaviors were studied. Based on the single-molecule level analysis, there are some conclusions： （1） In the electrolyte solution containing 50 mmol/L I（Cl and 450 mmol/L NaCl, ThT can bind strongly with Tel DNA but nearly does not change the G-quadruplex form; （2） in the presence of high concentration K~, the ThT binding induces the structural change of hybrid G-quadruplex into antiparallel topology with an enhanced structural stability; （3） In either alkaline or acidic buffer, G-quadruplex form will change in certain degree. All above conclusions are helpful to deeply understand the interaction behaviors between Tel DNA and ThT. This nanopore platform, investigating G-quadruplex ligands at the single-molecule level, has great potential for the design of new drugs and sensors.展开更多
In the present study,the distribution of Ag in the coating formed on Mg-Ag alloy by plasma electrolytic oxidation(PEO)and its ionic release kinetics when exposed to a 0.9 wt.%Na Cl solution at 37℃have been investigat...In the present study,the distribution of Ag in the coating formed on Mg-Ag alloy by plasma electrolytic oxidation(PEO)and its ionic release kinetics when exposed to a 0.9 wt.%Na Cl solution at 37℃have been investigated.Both metallic Ag and Ag oxide particles with~5 to~40 nm in diameters were observed in the PEO coating.Further,an Ag-enriched layer of~20 nm in thickness at the substrate/coating interface was also observed.The PEO coating on the Mg-Ag alloy not only increases its corrosion resistance with the corrosion current density decreasing by up to 3 orders of magnitude from 8.04×10^(-3)to 4.03×10^(-6)A/cm^(2),but also controls the release of Ag+to the level that is sufficient for anti-infective efficacy without causing cytotoxicity to mammal cells.展开更多
基金supported by the Research Fund Project of the Education Department of Yunnan Province(No.2023Y0464)Research Project for Scientific Research Funds of Provincial Research Institutions in Heilongjiang Province(No.CZBZ2025ZR003).
文摘Background:Immunosuppression compromises the host’s ability to combat pathogens,thereby increasing susceptibility to multisystem disorders.However,safe and effective curative treatments for this condition are currently lacking.Modulating the gut microbiota and their metabolites represents a promising therapeutic strategy.Notably,the Chinese herbal compound Yunzhi Guben Gao(YZG)has demonstrated multi-target immunomodulatory potential.Methods:A mouse model of dexamethasone-induced immunosuppression was employed to evaluate the effects of YZG.Immune organ indices(thymus,spleen),serum cytokine levels(IL-2,TNF-α),mucosal immunity markers(pulmonary/colonic SIgA),gut microbiota structure,and short-chain fatty acids(SCFAs)abundance were evaluated.Key microbial genera and metabolites were identified via Spearman correlation analysis.Pseudo-germ-free model mice established via quadruple antibiotic treatment combined with isovaleric acid intervention were employed to evaluate whether YZG efficacy depends on the intestinal microbiota and its metabolites,and whether its intrinsic mechanisms involve the promotion of isovaleric acid production.Results:YZG intervention ameliorated systemic and mucosal immune function in immunosuppressed mice.Mechanistically,YZG remodeled gut microbiota structure and significantly increased SCFAs levels.Notably,the abundance of the genus Ligilactobacillus exhibited the strongest positive correlation with isovaleric acid levels.Ligilactobacillus abundance was also positively correlated with immune-enhancing parameters and negatively correlated with the proinflammatory cytokine TNF-α,suggesting that Ligilactobacillus plays a pivotal role in the YZG regulatory network.Experiments using pseudo-germ-free mice and isovaleric acid intervention further demonstrated that the immunoprotective effects of YZG are closely related to intestinal microbiota remodeling and increased isovaleric acid production.Conclusion:YZG alleviates immunosuppression through multiple mechanisms,primarily involving the enrichment of the probiotic genus Ligilactobacillus and the consequent increase in isovaleric acid production.This process coordinately modulates mucosal immunity,cytokine networks,and immune organ function.The elucidation of this“microbiota-metabolite-immunity”axis provides both a pharmacological basis for the clinical application of YZG and novel immune-restorative strategies targeting gut microecological regulation.
基金supported by the National Key R&D Program of China(grant No.2024YFA1611600)the SVOM project(a mission under the Strategic Priority Program on Space Science of the Chinese Academy of Sciences)+23 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB0550401)the National Natural Science Foundation of China(NSFC,grant No.12494573)partly supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region(grant No.2024D01D32)Tianshan Talent Training Program(grant No.2023TSYCLJ0053)Tianshan Innovation Team Program(grant No.2024D14015)supported by the Jiangsu Funding Program for Excellent Postdoctoral Talent(grant No.2024ZB110)the Postdoctoral Fellowship Program(grant No.GZC20241916)the General Fund(grant No.2024M763531)of the China Postdoctoral Science Foundationsupported by a Royal Society Dorothy Hodgkin Fellowship(grant Nos.DHF-R1-221175 and DHF-ERE-221005)support by a postdoctoral fellowship from the CNESsupported by the National Key R&D Program of China(grant No.2024YFA1611702)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB0550101)the support of the French Agence Nationale de la Recherche(ANR),under grant ANR-23-CE31-0011(project PEGaSUS)financial support from the GRAWITA Large Program Grant(PI P.D’Avanzo)financial support from the Italian Space Agency,contract ASI/INAF No.I/004/11/6support from the INAF project Premiale Supporto Arizona&Italiasupported by the National Natural Science Foundation of China(NSFC,grant No.12133003)supported by the National Natural Science Foundation of China(NSFC,grant No.12373042)the Bagui Scholars Program(No.GXR-6BG2424001)funded by the European Union(ERC,HEAVYMETAL,101071865,Views and opinions expressed are,however,those of the authors only and do not necessarily reflect those of the European Union or the European Research Council Neither the European Union nor the granting authority can be held responsible for them)the Cosmic Dawn Center(DAWN)is funded by the Danish National Research Foundation under grant No.DNRF140supported by the National Natural Science Foundation of China(NSFC,grant Nos.12225305 and 12321003)supported by the National Natural Science Foundation of China(NSFC,grant No.12473049)supported by the General Fund(grant No.2024M763530)of the China Postdoctoral Science Foundation。
文摘Early multiwavelength observations offer crucial insights into the nature of the relativistic jets responsible for gamma-ray bursts and their interaction with the surrounding medium.We present data of GRB 240825A from 17 space-and ground-based telescopes/instruments,covering wavelengths from NIR/optical to X-ray and GeV,and spanning from the prompt emission to the afterglow phase triggered by Swift and Fermi.The early afterglow observations were carried out by SVOM/C-GFT,and spectroscopic observations of the afterglow by GTC,VLT,and TNG determined the redshift of the burst(z=0.659)later.A comprehensive analysis of the prompt emission spectrum observed by Swift-BAT and Fermi-GBM/LAT reveals a rare and significant high-energy cutoff at 76 MeV.Assuming this cutoff is due toγγabsorption allows us to place an upper limit on the initial Lorentz factor,Γ_(0)<245.The optical/NIR and GeV afterglow light curves can be described by the standard external shock model,with early-time emission dominated by a reverse shock(RS)and a subsequent transition to forward shock(FS)emission.Our afterglow modeling yields a consistent estimate of the initial Lorentz factor(Γ_(0)∼234).Furthermore,the RS-to-FS magnetic field ratio(R 302B)indicates that the RS region is significantly more magnetized than the FS region.An isotropic-equivalent kinetic energy of E_(k,iso)=5.25×10^(54) erg is derived,and the correspondingγ-ray radiation efficiency is estimated to beη_(γ)=3.1%.On the other hand,the standard afterglow model cannot reproduce the X-ray light curve of GRB 240825A,calling for improved models to characterize all multiwavelength data.
基金the National Natural Science Foundation of China(No.52371065)the Hubei Provincial Natural Science Foundation of China(No.2023AFB637).
文摘Magnesium(Mg)-based implants have been clinically proven to fulfill long-term service requirements,but their passive degradation periods remain to be uncontrollable.Herein,we developed a novel near infrared(NIR)-responsive coating on a Mg-Ag-Mn alloy with controllable biodegradation enhanced by air release.The coating exhibits a bi-layered structure,in which the outer layer consists of polycaprolactone(PCL)with the addition of nano-sized polypyrrole(PPy)particles for NIR response,whereas the inner layer is a porous ceramic film produced via plasma electrolytic oxidation(PEO).In particular,the porous structure of PEO film was proposed as a carrier for entrapped air to form the“air bomb”.Without NIR irradiation,the coating possesses a dense and homogeneous microstructure and exhibits excellent long-term durability in saline.Under the NIR irradiation,the PCL resin transforms from a rubbery state to a viscous state promoted by the photothermal action of PPy,while the thermal-expanded air in PEO film escapes from the PCL resin,resulting in macroscopic defects across the coating.This phenomenon leads to a change in the function of Mg alloy from"anti-corrosion"to"biodegradation".This work is expected to provide a new strategy for optimizing the service time of Mg-based implants.
基金supported by the National Natural Science Foundation of China(No.52371065).
文摘The present work investigates the corrosion behaviour of an AA2024 alloy thin wall structure produced by wire arc additive manufacturing(WAAM)with interpass rolling,focussing on the influence of interpass rolling.It is found that although interpass rolling does not change the typical configuration of thin wall structure,i.e.melt pool zone(MPZ),melt pool border(MPB)and heat-affected zone(HAZ),the plastic deformation introduced by interpass rolling leads to the variation of grain-stored energy across the structure,which consequently results in the highest corrosion susceptibility of MPB due to its relatively high stored energy.
基金support to this work:the National Natural Science Foundation of China(grant No.50971064,No.51361004)the Innovative Foundation of HUST(grant 2017KFYXJJ164).
文摘Magnesium implants have received widespread attention in orthopaedic surgery.However,the mechanical degradation and concurrent inflammation caused by the rapid corrosion of Mg limits their applications.In this study,a kind of unique core-shell heterojunction CuS@PPy nanostructures was synthesized and then incorporated in polycaprolactone(PCL)to construct an intelligent coating(CuS@PPy/PCL)on micro-arc-oxidized Mg implants.The PCL-based coating can realize near-infrared(NIR)-driven antibacterial and controllable Mg dissolution according to different bone healing stages.At the beginning of bone remodelling,the coating exhibits promising antibacterial properties with 99.67%and 99.17%efficacy against S.aureus and E.coli,respectively,thanks to the singlet oxygen(^(1)O_(2))and alkoxyl radicals(RO·)generated by the photodynamic effect of CuS@PPy heterojunction under low-power NIR light(1.5 W/cm^(2)).In the bone reparative stage,the PCL-based coating can maintain high corrosion resistance to meet the mechanical requirements of Mg implants in human body fluid.However,after the complete rehabilitation of bones,through a high-power(2 W/cm^(2))NIR light,the PCL-based coating changed from an elastic to a viscous flow state(44.7℃)under the photothermal effects of CuS@PPy,leading to quick degradation of the PCL-based coating and following accelerating dissolution of the Mg implant(avoiding secondary surgery).Hopefully,this NIR-responsive coating may provide an innovative method for the antibacterial and controllable dissolution of Mg implants.
基金financially supported by the National Natural Science Foundation of China(No.51273210)Natural Science Foundation of Ningbo Municipal(No.2015A610021)K.C.Wong Magna Fund in Ningbo University
文摘The gel-spun ultra-high molecular weight polyethylene （UHMWPE） fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultimate structure and mechanical properties of UHMWPE fibers for different gel solution concentrations were analyzed by tensile testing, differential scanning calorimetry （DSC）, wide angle X-ray diffraction （WAXD） and small angle X-ray scattering （SAXS）. With the increase of gel solution concentration, the ultimate mechanical properties of UHMWPE fibers were decreased and the crystallization and orientation of UHMWPE fibers became inferior. Besides, both the average shish length （ （Lshsh） ） and shish misorientation （B0） of UHMWPE fibers were decreased with the increase of gel solution concentration. In addition, the appropriate increase of spinning temperature led to the further optimization of the ultimate structure and mechanical properties of UHMWPE fibers.
基金Supported by Natural Science Foundation of Minhang District of Shanghai,No.2012MHZ001
文摘AIM To investigate the effect of epigallocatechin gallate(EGCG) on structural changes of gut microbiota in colorectal carcinogenesis.METHODS An azoxymethane(AOM)/dextran sodium sulfate(DSS)-induced colitis mouse model was established. Fortytwo female FVB/N mice were randomly divided into the following three groups: group 1(10 mice, negative control) was treated with vehicle, group 2(16 mice, positive control) was treated with AOM plus vehicle, and group 3(16 mice, EG) was treated with AOM plus EGCG. For aberrant crypt foci(ACF) evaluation, the colons were rapidly took out after sacrifice, rinsed with saline, opened longitudinally, laid flat on a polystyrene board, and fixed with 10% buffered formaldehyde solution before being stained with 0.2% methylene blue in saline. For tumor evaluation, the colon was macroscopically inspected and photographed, then the total number of tumors was enumerated and tumor size measured. For histological examination, the fixed tissues were paraffin-embedded and sectioned at 5 mm thickness. Microbial genomic DNA was extracted from fecal and intestinal content samples using a commercial kit. The V4 hypervariable regions of 16 S r RNA were PCR-amplified with the barcoded fusion primers. Using the best hit classification option, the sequences from each sample were aligned to the RDP 16 S r RNA training set to classify the taxonomic abundance in QIIME. Statistical analyses were then performed.RESULTS Treatment of mice with 1% EGCG caused a significant decrease in the mean number of ACF per mouse, when compared with the model mice treated with AOM/DSS(5.38 ± 4.24 vs 13.13 ± 3.02, P < 0.01). Compared with the positive control group, 1% EGCG treatment dependently decreased tumor load per mouse by 85%(33.96 ± 6.10 vs 2.96 ± 2.86, respectively, P < 0.01). All revealed that EGCG could inhibit colon carcinogenesis by decreasing the number of precancerous lesions as well as solid tumors, with reduced tumor load and delayed histological progression of CRC. During the cancerization, the diversity of gut microbiota increased, potential carcinogenic bacteria such as Bacteroides were enriched, and the abundance of butyrate-producing bacteria(Clostridiaceae, Ruminococcus, etc.) decreased continuously. In contrast, the structure of gut microbiota was relatively stable during the intervention of EGCG on colon carcinogenesis. Enrichment of probiotics(Bifidobacterium, Lactobacillu, etc.) might be a potential mechanism for EGCG's effects on tumor suppression. Via bioinformatics analysis, principal coordinate analysis and cluster analysis of the tumor formation process, we found that the diversity of gut microbiota increased in the tumor model group while that in the EGCG interfered group(EG) remained relatively stable.CONCLUSION Gut microbiota imbalance might be a potential mechanism for the prevention of malignant transformation by EGCG, which is significant for diagnosis, treatment, prognosis evaluation, and prevention of colorectal cancer.
基金Supported by the Scientific Research Project of Shanghai Health and Family Planning,and the Commission and the 5th People’s Hospital of Shanghai,Fudan University under Grant No.201440505
文摘AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant proBFT-2 was expressed in Escherichia coli strain Rosetta (DE3) and BFT-2 was obtained and tested for its biological activity via colorectal adenocarcinoma cell strains SW-480. Seventy C57BL/6J mice were randomly divided into a blank (BC; n = 10), model (AD; n = 20), model + low-dose toxin (ADLT; n = 20, 10 mu g), and a model + high-dose toxin (ADHT; n = 20, 20 mu g) group. Mice weight, tumor formation and pathology were analyzed. Immunohistochemistry determined Ki-67 and Caspase-3 expression in normal and tumor tissues of colorectal mucosa. RESULTS Recombinant BFT-2 was successfully obtained, along with its biological activity. The most obvious weight loss occurred in the AD group compared with the ADLT group (21.82 +/- 0.68 vs 23.23 +/- 0.91, P < 0.05) and the ADHT group (21.82 +/- 0.68 vs 23.57 +/- 1.06, P < 0.05). More tumors were found in the AD group than in the ADLT and ADHT groups (19.75 +/- 3.30 vs 6.50 +/- 1.73, P < 0.05; 19.75 +/- 3.30 vs 6.00 +/- 2.16, P < 0.05). Pathology showed that 12 mice had adenocarcinoma and 6 cases had adenoma in the AD group. Five mice had adenocarcinoma and 15 had adenoma in the ADLT group. Four mice had adenocarcinoma and 16 had adenoma in the ADHT group. The incidence of colorectal adenocarcinoma in both the ADHT group and the ADHT group was reduced compared to that in the AD group (P < 0.05, P < 0.05). The positive rate of Ki-67 in the ADLT group and the ADHT group was 50% and 40%, respectively, both of which were lower than that found in the AD group (94.44%, P < 0.05, P < 0.05). Caspase-3 expression in the ADLT group and the ADHT group was 45% and 55%, both of which were higher than that found in the BC group (16.67%, P < 0.05, P < 0.05). CONCLUSION Oral administration with lower-dose biologically active recombinant BFT-2 inhibited colorectal tumorigenesis in mice.
基金financially supported by Natural Science Foundation of Zhejiang Province(No.LY15B040003)K.C.Wong Magna Fund in Ningbo University
文摘The multiple endothermic peaks of poly（3-hydroxybutyrate-co-3-hydroxyvalerate） （P（HB-co-HV）） in differential scanning calorimetry （DSC） results, as one representative phenomenon of polymer with unique cocrystallization behavior, were generally considered as the results of melting/recrystallization. In this study, wide angle X-ray diffraction （WAXD） and small angle X-ray scattering （SAXS） experiments were conducted to analyze the phenomena of multiple endothermic peaks in DSC results. The results of these analyses indicated that the multiple endotherms were mainly caused by different lamellae structures. For P（HB-co-HV） with lower HV content, it was comprised of two structures of HV total exclusion and HV partial inclusion in the crystal lamellae. For P（HB-co-HV） with higher HV content, it was also comprised of two structures of HV total inclusion and HV partial inclusion in the crystal lamellae. However, only structure with HV partial inclusion in the crystal lamellae remained existing after first melting peak for all samples.
基金supported by the National Natural Science Foundation of China(Nos.52001128 and 52371065)the Hubei Provincial Natural Science Foundation of China(No.2023AFB637).
文摘The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of Mg-Ag-Mn alloys is investigated with the underlying microstructural factors examined. The Mg-Ag alloy with 2 wt% Mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of Mn results in α-Mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-Mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.
基金financially supported by the National Natural Science Foundation of China(Nos.51273210,51003117 and 5140030545)Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of SciencesK.C.Wong Magna Fund in Ningbo University
文摘Ultra-high molecular weight polyethylene（UHMWPE）/chitin nanocrystal（CNC） fibers were prepared. Compared with the pure UHMWPE fibers, the ultimate tensile strength and Young＇s modulus of UHMWPE/CNC fibers are improved by 15.7% and 49.6%, respectively, with the addition of chitin nanocrystals（CNCs） of 1 wt%. The melting temperature（Tm） of UHMWPE/CNC fibers was higher than that of pure UHMWPE fibers. Pure UHMWPE fibers and UHMWPE/CNC fibers were characterized with respect to crystallinity, orientation and kebab structure by wide-angle X-ray diffraction（WAXD）, small-angle X-ray scattering（SAXS） and scanning electron microscopy（SEM）. It is found that the CNCs act as the shish structure in UHMWPE/CNC fibers and the kebab crystals are grown around the CNCs. There was almost no difference between pure UHMWPE fibers and UHMWPE/CNC fibers in orientation. But the degree of crystallinity of various stages of UHMWPE/CNC fibers was respectively higher than the corresponding stage of pure UHMWPE fibers. Moreover, the addition of 1 wt% CNCs improved the thickness of kebab crystals and accelerated the transformation of kebab to shish.
基金supported by the National Natural Science Foundation of China(No.51273210)the Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied ChemistryChinese Academy of Sciences and the K.C.Wong Magna Fund in Ningbo University
文摘Microbeam wide-angle X-ray diffraction（WAXD） experiments were carried out at different structural knot positions of SIOC and M4 fibers of ultra-high molecular weight polyethylene（UHMWPE）. The optical microscope images revealed that SIOC fiber had bamboo-like structural knots, and M4 fiber had chaotic distribution of structural knots. WAXD patterns showed the monoclinic unit cell in the whole M4 fiber, but different lamellar orientations in the bamboo joint of SIOC fiber. In addition, small-angle X-ray scattering（SAXS） patterns confirmed that the SIOC fiber contained uniform distribution of shish structures, and differential scanning calorimetry（DSC） measurements showed that its less branched and short chains benefited the orthorhombic-hexagonal phase transformation.
基金Supported by the National Natural Science Foundation of China。
文摘We will introduce the construction and design of a new simultaneous three-channel multicolor CCD photometer.This photometer has been mounted on the 1.2 m telescope at Jilin Astronomical Observatory,and is applied to study space debris,gamma-ray burst afterglows,asteroids and other rapidly variable objects.As one of the ground follow-up telescopes of the Chinese-French Space-based multi-band astronomical Variable Objects Monitor(SVOM)mission,it appears very essential to evaluate the performance of the photometry system of this photometer,which can achieve simultaneous imaging within a field of view of 21’.5×21’.5,21’.5×21’.5 and21’.3×21’.3 in the Sloan Digital Sky Survey(SDSS)g’,r’,i’bands,respectively.Photometric calibrations were carried out by using plenty of SDSS standard stars,and the relationship between the photometric system and the Johnson-Bessel filter system was also studied.The results of the performance evaluation from observing open cluster M67 are presented.
基金financially supported by the National Natural Science Foundation of China(No. 21475091)the Science andTechnology Department of Sichuan Province(No. 2015GZ0301)
文摘G-quadruplex ligands have been accepted as potential therapeutic agents for anticancer treatment. Thioflavin T （ThT）, a highly selective G-quadruplex ligand, can bind G-quadruplex with a fluorescent light-up signal change and high specificity against DNA duplex. However, there are still different opinions that ThT induces/stabilizes G-quadruplex foldings/topologies in human telomere sequence. Here, a sensitive single-molecule nanopore technology was utilized to analyze the interactions between human telomeric DNA （Tel DNA） and ThT. Both translocation time and current blockade were measured to investigate the translocation behaviors. Furthermore, the effects of metal ion （K~ and Na~） and pH on the translocation behaviors were studied. Based on the single-molecule level analysis, there are some conclusions： （1） In the electrolyte solution containing 50 mmol/L I（Cl and 450 mmol/L NaCl, ThT can bind strongly with Tel DNA but nearly does not change the G-quadruplex form; （2） in the presence of high concentration K~, the ThT binding induces the structural change of hybrid G-quadruplex into antiparallel topology with an enhanced structural stability; （3） In either alkaline or acidic buffer, G-quadruplex form will change in certain degree. All above conclusions are helpful to deeply understand the interaction behaviors between Tel DNA and ThT. This nanopore platform, investigating G-quadruplex ligands at the single-molecule level, has great potential for the design of new drugs and sensors.
基金the financial support from the Hubei Provincial Natural Science Foundation of China(No.2020CFB295)the National Natural Science Foundation of China(No.52001128)+1 种基金the Innovative Foundation of Huazhong University of Science and Technology(No.2021JYCXJJ023)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B21003)。
文摘In the present study,the distribution of Ag in the coating formed on Mg-Ag alloy by plasma electrolytic oxidation(PEO)and its ionic release kinetics when exposed to a 0.9 wt.%Na Cl solution at 37℃have been investigated.Both metallic Ag and Ag oxide particles with~5 to~40 nm in diameters were observed in the PEO coating.Further,an Ag-enriched layer of~20 nm in thickness at the substrate/coating interface was also observed.The PEO coating on the Mg-Ag alloy not only increases its corrosion resistance with the corrosion current density decreasing by up to 3 orders of magnitude from 8.04×10^(-3)to 4.03×10^(-6)A/cm^(2),but also controls the release of Ag+to the level that is sufficient for anti-infective efficacy without causing cytotoxicity to mammal cells.
