[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significant...[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significantly reduce energy consumption,pollution emissions and reliance on fossil fuels.Bipolar plates are the major part and key component of PEMFCs stack,which provide mechanical strength,collect and conduct current segregate oxidants and reduce agents.They contribute 70-80%weight and 20-30%cost of a whole stack,while significantly affecting the power density.There are three types plates,including metal bipolar plate,graphite bipolar plate and composite bipolar plate.Stainless steel bipolar plates,as one of metal bipolar plate,exhibit promising manufacturability,competitive cost and durability among various metal materials.However,stainless steel would be corroded in the harsh acid(pH 2-5)and humid PEMFCs environment,whereas the leached ions will contaminate the membrane.In addition,the passivated film formed on the surface will increase the interfacial contact resistance(ICR).In order to improve the corrosion resistance and electrical conductivity of steel bipolar plates,surface coatings are essential.Metal nitride coatings,metal carbide coatings,polymer coatings and carbon-based coatings have been introduced in recent years.Carbon-based coatings,mainly including a-C(amorphous Carbon),Ta-C(Tetrahedral amorphous carbon)and DLC(diamond-like carbon),have attracted considerable attention from both academia and industry,owing to their superior performance,such as chemical inertness,mechanical hardness and electrical conductivity.However,Ta-C films as protective coating of PEMFCs have been rarely reported,due to the difficulty in production for industrial application.In this paper,multi-layer Ta-C composite films were produced by using customized industrial-scale vacuum equipment to address those issues.[Methods]Multiple layered Ta-C coatings were prepared by using PIS624 equipment,which assembled filtered cathodic arc evaporation,ion beam and magnetron sputtering into one equipment,while SS304 and silicon specimens were used as substrate for testing and analysis.Adhesion layer and intermediate layer were deposited by using magnetron sputtering at deposition temperature of 150℃and pressure of 3×10^(−1) Pa,while the sputtering current was set to be 5 A and bias power to be 300 V.The Ta-C layer was coated at arc current of 80-100 A,bias voltage of 1500 V and gas flow of 75 sccm.A scanning electron microscope(CIQTEK SEM3200)was used to characterize surface morphology,coating structure and cross-section profile of the coatings.Raman spectrometer(LabRam HR Evolution,HORIBA JOBIN YVON)was used to identify the bonding valence states.Electrochemical tests were performed by using an electrochemical work station(CHI760,Shanghai Chenhua Instrument Co.,Ltd.),with the traditional three electrode system,where saturated Ag/AgCl and platinum mesh were used as the reference electrode and counter electrode,respectively.All samples were mounted in plastic tube and sealed with epoxy resin,with an exposure area of 2.25 cm^(2),serving as the working electrode.Electrochemical measurements were carried out in simulated PEMFCs cathode environment in 0.5 mol·L^(−1) H_(2)SO_(4)+5 ppm F−solution,at operating temperature of 70℃.As the cathode environment was harsher than the anode environment,all the samples are stabilized at the open-circuit potential(OCP)for approximately 30 min before the EIS measurements.ICR between bipolar plates and GDL was a key parameter affecting performance of the PEMFCs stack.The test sample sandwiched between 2 pieces of carbon paper(simulate gas diffusion layer,GDL)was placed between 2 gold-plated copper electrodes at a compaction pressure of 1.4 MPa,which was considered to be the conventional compaction pressure in the PEMFCs.Under the same conditions,the resistance of a single carbon paper was measured as well.The ICR was calculated according to the formula ICR=1/2(R2−R1)×S,where S was the contact area between GDL and coated stainless steel BPPs.All data of ICR were measured three times for averaging.[Results]The coatings deposited by filtered cathodic arc technology were compact and smooth,which reduced coating porosity and favorable to corrosion resistance.The coating thickness of adhesion and intermediate layers were 180 nm,while the protective Ta-C coating thickness was about 300 nm,forming multiple coating to provide stronger protection for metal bipolar plates.Cr,Ti,Nb and Ta coatings were selected as adhesion layers for comparison.According to electrochemical test,Ta and Nb coatings have higher corrosion resistance.However,Ta and Nb materials would be costly when they are used for mass production.Relatively,Cr and Ti materials were cost effective.Hence,a comprehensive assessment was indispensable to decide the materials to be selected as adhesion layer.Ta-TiN and Ti-TiN combined adhesion and intermediate layer exhibited stronger corrosion resistance,with the corrosion current to be less than 10^(−6) A·cm^(−2).Ta-C protective coating deposited by using filtered cathodic arc technology indicated displayed higher corrosion resistance,with the average corrosion density to be about 1.26×10^(−7) A·cm^(−2).Ta-C coating also shown larger contact angle,with the highest hydrophobicity,which was one of the important advantages for Ta-C,in terms of corrosion resistance.According to Raman spectroscopy,the I(D)/I(G)=549.8/1126.7=0.487,with the estimated fraction of sp^(3) bonding to be in the range of 5154%.The intermediate layer TiN has higher conductivity than the CrN layer.Considering cost,corrosion performance and ICR result,the Ti-TiN layer combination is recommended for industrial scale application.[Conclusions]Multiple layer coating structure of Ta-C film had stronger corrosion resistance;with more than 50%sp^(3) content,while it also had larger water contact angle and higher corrosion resistance than DLC film.The filtered arcing deposition technology was able to make the film to be more consistent and stable than normal arcing technology in terms of the preparation of Ta-C.The coating displayed corrosion density of 1.26×10^(−7) A·cm^(−2) and ICR of less than 5 mΩ·cm^(2),far beyond technical target of 2025 DOE(US Department of Energy).This indicated that the mass-production scale coating technology for PEMFC bipolar plates is highly possible.展开更多
Osteogenic ability impairment and myelosuppression are common complications of chemotherapy and many chemotherapeutics can affect the skeletal system.Skeletal system protection is necessary for cancer chemotherapy.In ...Osteogenic ability impairment and myelosuppression are common complications of chemotherapy and many chemotherapeutics can affect the skeletal system.Skeletal system protection is necessary for cancer chemotherapy.In this study,osteogenic growth peptide(OGP)and tetrahedral framework nucleic-acid nanostructures(tFNAs)are combined to form a peptide-DNA complex OGP-tFNAs,which aims to combine the positive biological effect on tissue protection and regeneration.The bone marrow protection and bone formation effect of OGP-tFNAs are investigated in chemotherapy-induced myelosuppressive mice.The results show that OGP-tFNAs could reduce the cell damage degree from 5-fluorouracil(5-FU)in vitro and maintained the osteogenic differentiation potential.Furthermore,OGP-tFNAs accelerate bone defect regeneration in myelosuppressive mice.In conclusion,OGP-tFNAs could protect the osteogenic differentiation potential of bone marrow stromal cells(BMSCs)from 5-FU injury and maintain the bone formation ability of myelosuppressive mice suffering from chemotherapy.展开更多
Neuropathic pain(NP)is one of the most common pathological pain types and is associated with limited treatment options;moreover,it affects patients’quality of life and causes a heavy social burden.Despite the emphasi...Neuropathic pain(NP)is one of the most common pathological pain types and is associated with limited treatment options;moreover,it affects patients’quality of life and causes a heavy social burden.Despite the emphasis on inhibiting neuronal apoptosis to relieve NP,the crucial role of a neuroinflammation is often overlooked.Therefore,refocusing on the regulation of microglia polarization to create a more conducive environment for neuron holds great potential in NP treatment.In recent years,small interfering RNAs(siRNAs)had become an attractive therapeutic option.However,an efficient loading and delivery system for siRNA is still in lack.In our study,a nanostructured tetrahedral framework nucleic acid loaded with the small interfering RNA C–C chemokine receptor 2(T-siCCR2)was successfully designed and synthesized for use in NP rat model in vivo and in a lipopolysaccharide(LPS)-induced inflammatory environment in vitro.This nanoscale complex is endowed with structural stability and satisfactory delivery efficiency while assuring the silencing effect of siRNA-CCR2.In vivo,T-siCCR2 treatment exhibited favorable effects on pain relief and functional improvement in the NP animal model by directly targeting microglia.In vitro,T-siCCR2 counteracts LPS-induced inflammation by inhibiting the differentiation of microglia toward the M1 phenotype,thus playing a neuroprotective role.RNA sequencing was subsequently performed to elucidate the underlying mechanism involved.These results indicate that T-siCCR2 may serve as a potential treatment option for NP in the future.展开更多
Diabetic kidney disease(DKD)is recognized as a severe complication in the development of diabetes mellitus(DM),posing a significant burden for global health.Major characteristics of DKD kidneys include tubulointerstit...Diabetic kidney disease(DKD)is recognized as a severe complication in the development of diabetes mellitus(DM),posing a significant burden for global health.Major characteristics of DKD kidneys include tubulointerstitial oxidative stress,inflammation,excessive extracellular matrix deposition,and progressing renal fibrosis.However,current treatment options are limited and cannot offer enough efficacy,thus urgently requiring novel therapeutic approaches.Tetrahedral framework nucleic acids(tFNAs)are a novel type of self-assembled DNA nanomaterial with excellent structural stability,biocompatibility,tailorable functionality,and regulatory effects on cellular behaviors.In this study,we established an in vitro high glucose(HG)-induced human renal tubular epithelial cells(HK-2 cells)pro-fibrogenic model and explored the antioxidative,anti-inflammatory,and antifibrotic capacity of tFNAs and the potential molecular mechanisms.tFNAs not only effectively alleviated oxidative stress through reactive oxygen species(ROS)-scavenging and activating the serine and threonine kinase(Akt)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)signaling pathway but also inhibited the production of proinflammatory factors such as tumor necrosis factor(TNF-α),interleukin-1β(IL-1β),and interleukin-6(IL-6)in diabetic HK-2 cells.Additionally,tFNAs significantly downregulated the expression of Collagen I andα-smooth muscle actin(α-SMA),two representative biomarkers of pro-fibrogenic myofibroblasts in the renal tubular epithelial-mesenchymal transition(EMT).Furthermore,we found that tFNAs exerted this function by inhibiting the Wnt/β-catenin signaling pathway,preventing the occurrence of EMT and fibrosis.The findings of this study demonstrated that tFNAs are naturally endowed with great potential to prevent fibrosis progress in DKD kidneys and can be further combined with emerging pharmacotherapies,providing a secure and efficient drug delivery strategy for future DKD therapy.展开更多
We theoretically study the effect of a uniform orbital magnetic field on spin waves in a triangular lattice tetrahedral antiferromagnetic insulator without spin–orbit coupling. Through symmetry analysis and microscop...We theoretically study the effect of a uniform orbital magnetic field on spin waves in a triangular lattice tetrahedral antiferromagnetic insulator without spin–orbit coupling. Through symmetry analysis and microscopic calculation, we show that the optical spin wave mode at the Brillouin zone center can acquire a small orbital magnetic moment, although it exhibits no magnetic moment from the Zeeman coupling. Our results are potentially applicable to intercalated van der Waals materials and twisted double-bilayer graphene.展开更多
Hyperglycemia resulting from diabetes mellitus(DM)exacerbates osteoporosis and fractures,damaging bone regeneration due to impaired healing capacity.Stem cell therapy offers the potential for bone repair,accelerating ...Hyperglycemia resulting from diabetes mellitus(DM)exacerbates osteoporosis and fractures,damaging bone regeneration due to impaired healing capacity.Stem cell therapy offers the potential for bone repair,accelerating the healing of bone defects by introducing stem cells with osteogenic differentiation ability.Dental follicle stem cells(DFSCs)are a newly emerging type of dental stem cells that not only have the potential for multipotent differentiation but also hold easy accessibility and can stand longterm storage.However,DM-associated oxidative stress and inflammation elevate the risk of DFSCs dysfunction and apoptosis,diminishing stem cell therapy efficacy.Recent nanomaterial advances,particularly in DNA nanostructures like tetrahedral framework nucleic acids(tFNAs),have been promising candidates for modulating cellular behaviors.Accumulating experiments have shown that tFNAs’cell proliferation and migration-promoting ability and induce osteogenic differentiation of stem cells.Meanwhile,tFNAs can scavenge reactive oxygen species(ROS)and downregulate the secretion of inflammatory factors by inhibiting various inflammation-related signaling pathways.Here,we applied tFNAs to modify DFSCs and observed enhanced osteogenic differentiation alongside ROS scavenging and anti-inflammatory effects mediated by suppressing the ROS/mitogen-activated protein kinases(MAPKs)/nuclear factor kappa-B(NF-κB)signaling pathway.This intervention reduced stem cell apoptosis,bolstering stem cell therapy efficacy in DM.Our study establishes a simple yet potent tFNAs-DFSCs system,offering potential as a bone repair agent for future DM treatment.展开更多
The innovation in polymer design to rival conventional polyethylene glycol(PEG)is an important approach to achieving a more sustainable society.Here,cyclic PEG-like polycarbonates having high molecular weight(4.4–49....The innovation in polymer design to rival conventional polyethylene glycol(PEG)is an important approach to achieving a more sustainable society.Here,cyclic PEG-like polycarbonates having high molecular weight(4.4–49.5 kg/mol)were enabled through zwitterionic ring-opening polymerization(ZROP)of macrocyclic carbonates(MCs)mediated by N-heterocyclic carbene(NHC).The thermodynamic behavior of polymerization depends on the ring size of monomers.During this process,the ZROP of 11-membered MC was driven by the change of enthalpy(ΔH_(p))which differed from the ZROP of 14-membered MC driven by the entropic change(ΔS_(p)).Cyclic polycarbonates depicted improved thermostability(T_(d5%)≥204℃)and higher glass transition temperatures(T_(g)>–40℃)in comparison to their linear analogues(T_(d5%)≤185℃,T_(g)~–50℃).In addition,the mechanism of ZROP of MC was addressed through computational study.A distinct mechanism of polymerization distinguishable from the well-known NHC-mediated ZROP of cyclic esters was revealed,where the zwitterion from nucleophilic addition to MC,i.e.tetrahedral intermediate,cannot be ring-opened probably due to the delocalization of negative charge on the carbonate group,but serves as an active center for the polymerization.In comparison to PEG,the attained polymer demonstrated comparable hydrophilic and biocompatible properties,as revealed by the results of contact angle and in vitro cytotoxicity studies,suggesting that cyclic polycarbonate hold the promise as the alternative of PEG.展开更多
This article reviews the latest research advances of tetrahedral framework nucleic acid(t FNA)-based systems in their fabrication,modification,and the potential applications in biomedicine.TFNA arises from the synthes...This article reviews the latest research advances of tetrahedral framework nucleic acid(t FNA)-based systems in their fabrication,modification,and the potential applications in biomedicine.TFNA arises from the synthesis of four single-stranded DNA chains.Each chain contains brief sequences that complement those found in the other three,culminating in the creation of a pyramid-shaped nanostructure of approximately 10 nanometers in size.The first generation of t FNA demonstrates inherent compatibility with biological systems and the ability to permeate cell membrane effectively.These attributes translate into remarkable capabilities for regulating various cellular biological processes,fostering tissue regeneration,and modulating immune responses.The subsequent evolution of t FNA introduces enhanced adaptability and a relatively higher degree of biological stability.This advancement encompasses structural modifications,such as the addition of functional domains at the vertices or side arms,integration of low molecular weight pharmaceuticals,and the implementation of diverse strategies aimed at reversing multi-drug resistance in tumor cells or microorganisms.These augmentations empower t FNA-based systems to be utilized in different scenarios,thus broadening their potential applications in various biomedical fields.展开更多
Diabetes mellitus considerably affects bone marrow mesenchymal stem cells(BMSCs),for example,by inhibiting their proliferation and differentiation potential,which enhances the difficulty in endogenous bone regeneratio...Diabetes mellitus considerably affects bone marrow mesenchymal stem cells(BMSCs),for example,by inhibiting their proliferation and differentiation potential,which enhances the difficulty in endogenous bone regeneration.Hence,effective strategies for enhancing the functions of BMSCs in diabetes have farreaching consequences for bone healing and regeneration in diabetes patients.Tetrahedral framework nucleic acids(tFNAs)are nucleic acid nanomaterials that can autonomously enter cells and regulate their behaviors.In this study,we evaluated the effects of tFNAs on BMSCs from diabetic rats.We found that tFNAs could promote the proliferation,migration,and osteogenic differentiation of BMSCs from rats with type 2 diabetes mellitus,and inhibited cell senescence and apoptosis.Furthermore,tFNAs effectively scavenged the accumulated reactive oxygen species and activated the suppressed protein kinase B(Akt)signaling pathway.Overall,we show that tFNAs can recover the proliferation and osteogenic potential of diabetic BMSCs by alleviating oxidative stress and activating Akt signaling.The study provides a strategy for endogenous bone regeneration in diabetes and also paves the way for exploiting DNA-based nanomaterials in regenerative medicine.展开更多
The undesirable capacity loss after first cycle is universal among layered cathode materials,which results in the capacity and energy decay.The key to resolving this obstacle lies in understanding the effect and origi...The undesirable capacity loss after first cycle is universal among layered cathode materials,which results in the capacity and energy decay.The key to resolving this obstacle lies in understanding the effect and origin of specific active Li sites during discharge process.In this study,focusing on Ah-level pouch cells for reliability,an ultrahigh initial Coulombic efficiency(96.1%)is achieved in an archetypical Li-rich layered oxide material.Combining the structure and electrochemistry analysis,we demonstrate that the achievement of high-capacity reversibility is a kinetic effect,primarily related to the sluggish Li mobility during oxygen reduction.Activating oxygen reduction through small density would induce the oxygen framework contraction,which,according to Pauli repulsion,imposes a great repulsive force to hinder the transport of tetrahedral Li.The tetrahedral Li storage upon deep oxygen reduction is experimentally visualized and,more importantly,contributes to 6%Coulombic efficiency enhancement as well as 10%energy density improvement for pouch cells,which shows great potentials breaking through the capacity and energy limitation imposed by intercalation chemistry.展开更多
Three new maleate compounds have been synthesized and studied by infrared,25Mg NMR(Nuclear Magnetic Resonance)Spectroscopy and UV(Ultraviolet)-visible spectroscopies.The suggested structures for the three complexes ar...Three new maleate compounds have been synthesized and studied by infrared,25Mg NMR(Nuclear Magnetic Resonance)Spectroscopy and UV(Ultraviolet)-visible spectroscopies.The suggested structures for the three complexes are discrete with NH-Cl hydrogen bonds.The maleate anion is monochelating(compound 1 and 2)and bichelating(compound 3).The environment tin(IV)and magnesium center are octahedral and the zinc center environment is tetrahedral.In all the suggested structures,when extra hydrogen bonds are considered,supramolecular architectures are obtained.展开更多
One new hydrogenosuccinate and two succinate adduct and complex have been synthesized and studied by infrared,UV-Visible and NMR(Nuclear Magnetic Resonance Spectroscopy)^(119)Sn spectroscopies.The suggested structure ...One new hydrogenosuccinate and two succinate adduct and complex have been synthesized and studied by infrared,UV-Visible and NMR(Nuclear Magnetic Resonance Spectroscopy)^(119)Sn spectroscopies.The suggested structure is discrete,the hydrogenosuccinate behaving as a monodentate ligand or only involved in hydrogen bonding,the environment around the magnesium centre being triangular(compound 3).The succiate anion is a monochelating ligand(compound 1 and 2).In all the suggested structures,when extra hydrogen bonds are considered,supramolecular architectures are obtained(compound 2 and 3).展开更多
By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes ar...By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.展开更多
Three new salicylate complexes and derivatives have been synthesized and studied by infrared, 119Sn NMR and UV-visible spectroscopies. The suggested structures for the two compounds are discrete with NH-O and NH-Cl hy...Three new salicylate complexes and derivatives have been synthesized and studied by infrared, 119Sn NMR and UV-visible spectroscopies. The suggested structures for the two compounds are discrete with NH-O and NH-Cl hydrogen bonds. The salicylate oxyanion is monochelating for the first salicylate compound with an octahedral tin (IV) centre and monodentate for the second salicylate compound, the environments around the tin centre being tetrahedral. For the cooper complex, the salicylate ligand is monochelating and the environments around the copper atom centre are tetrahedral.展开更多
This paper presents a reconstruction algorithm to build a surface mesh approximating an object from an unorganized point sampling of the boundary object. It combines 3D Delaunay tetrahedralization and mesh-growing met...This paper presents a reconstruction algorithm to build a surface mesh approximating an object from an unorganized point sampling of the boundary object. It combines 3D Delaunay tetrahedralization and mesh-growing method and uses only once Delau- nay triangulation. It begins with 3D Delaunay triangulation of the sampling. Then initialize the surface mesh with seed facets se- lected from Delaunay triangulation. Selection is based on the angle formed by the circumscribing ball of incident tetrahedral. Finally, grow until complete the surface mesh based on some heuristic rules. This paper shows several experimental results that demonstrate this method can handle open and close surfaces and work efficiently on various object topologies except non-manifold surface with self-intersections. It can reproduce even the smallest details of well-sampled surfaces but not work properly in every under-sampled situation that point density is too low.展开更多
For storing and modeling three-dimensional(3D)topographic objects(e.g.buildings,roads,dykes,and the terrain),tetrahedralizations have been proposed as an alternative to boundary representations.While in theory they ha...For storing and modeling three-dimensional(3D)topographic objects(e.g.buildings,roads,dykes,and the terrain),tetrahedralizations have been proposed as an alternative to boundary representations.While in theory they have several advantages,current implementations are either not space efficient or do not store topological relationships(which makes spatial analysis and updating slow,or require the use of an expensive 3D spatial index).We discuss in this paper an alternative data structure for storing tetrahedralizations in a database management system(DBMS).It is based on the idea of storing only the vertices and stars of edges;triangles and tetrahedra are represented implicitly.It has been used previously in main memory,but not in a DBMS.We describe how to modify it to obtain an efficient implementation in a DBMS,and we describe how it can be used for modeling 3D topography.As we demonstrate with different real-world examples,the structure is compacter than known alternatives,it permits us to store attributes for any primitives,and has the added benefit of being topological,which permits us to query it efficiently.The structure can be easily implemented in most DBMS(we describe our implementation in PostgreSQL),and we present some of the engineering choices we made for the implementation.展开更多
Local mesh refinement is one of the key steps in the implementations of adaptive finite element methods. This paper presents a parallel algorithm for distributed memory parallel computers for adaptive local refinement...Local mesh refinement is one of the key steps in the implementations of adaptive finite element methods. This paper presents a parallel algorithm for distributed memory parallel computers for adaptive local refinement of tetrahedral meshes using bisection. This algorithm is used in PHG, Parallel Hierarchical Grid Chttp：//lsec. cc. ac. cn/phg/）, a toolbox under active development for parallel adaptive finite element solutions of partial differential equations. The algorithm proposed is characterized by allowing simukaneous refinement of submeshes to arbitrary levels before synchronization between submeshes and without the need of a central coordinator process for managing new vertices. Using the concept of canonical refinement, a simple proof of the independence of the resulting mesh on the mesh partitioning is given, which is useful in better understanding the behaviour of the biseetioning refinement procedure.展开更多
Osteoarthritis, a disorder characterized by articular cartilage deterioration, varying degrees of inflammation, and chondrocyte apoptosis, is the most common chronic joint disease. To slow or reverse its progression, ...Osteoarthritis, a disorder characterized by articular cartilage deterioration, varying degrees of inflammation, and chondrocyte apoptosis, is the most common chronic joint disease. To slow or reverse its progression, inflammation should be inhibited, and chondrocyte proliferation should be promoted. Tetrahedral framework nucleic acids can be internalized by chondrocytes(even inflammatory chondrocytes) and can enhance their proliferation and migration. Wogonin, a naturally occurring flavonoid,suppresses oxidative stress and inhibits inflammation. In this study, tetrahedral framework nucleic acids were successfully selfassembled and used to load wogonin. We confirmed the effective formation of tetrahedral framework nucleic acid/wogonin complexes by dynamic light scattering, zeta potential analysis, transmission electron microscopy, and fluorescence spectrophotometry. Tetrahedral framework nucleic acids, wogonin, and especially tetrahedral framework nucleic acid/wogonin complexes effectively alleviated inflammation in vitro and in vivo and prevented cartilage destruction. In addition, these materials remarkably downregulated the expression of inflammatory mediators and matrix metalloproteinases, upregulated chondrogenic markers, and promoted tissue inhibitor of metalloproteinase 1 and B-cell lymphoma 2 expression. In vivo, after treatment with tetrahedral framework nucleic acid/wogonin complexes, the bone mineral density in regenerated tissues was much higher than that found in the untreated groups. Histologically, the complexes enhanced new tissue regeneration, significantly suppressed chondrocyte apoptosis, and promoted chondrogenic marker expression. They also inhibited cell apoptosis, increased chondrogenic marker expression, and suppressed the expression of inflammatory mediators in osteoarthritis. Therefore, we believe that tetrahedral framework nucleic acid/wogonin complexes can be used as an injectable form of therapy for osteoarthritis.展开更多
The Tetrahedral Network(TEN) is a powerful 3-D vector structure in GIS, which has a lot of advantages such as simple structure, fast topological relation processing and rapid visualization. The difficulty of TEN appli...The Tetrahedral Network(TEN) is a powerful 3-D vector structure in GIS, which has a lot of advantages such as simple structure, fast topological relation processing and rapid visualization. The difficulty of TEN application is automatic creating data structure. Although a raster algorithm has been introduced by some authors, the problems in accuracy, memory requirement, speed and integrity are still existent. In this paper, the raster algorithm is completed and a vector algorithm is presented after a 3-D data model and structure of TEN have been introducted. Finally, experiment, conclusion and future work are discussed.展开更多
基金Major Science and technology projects of Anhui Province (202103a05020003)。
文摘[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significantly reduce energy consumption,pollution emissions and reliance on fossil fuels.Bipolar plates are the major part and key component of PEMFCs stack,which provide mechanical strength,collect and conduct current segregate oxidants and reduce agents.They contribute 70-80%weight and 20-30%cost of a whole stack,while significantly affecting the power density.There are three types plates,including metal bipolar plate,graphite bipolar plate and composite bipolar plate.Stainless steel bipolar plates,as one of metal bipolar plate,exhibit promising manufacturability,competitive cost and durability among various metal materials.However,stainless steel would be corroded in the harsh acid(pH 2-5)and humid PEMFCs environment,whereas the leached ions will contaminate the membrane.In addition,the passivated film formed on the surface will increase the interfacial contact resistance(ICR).In order to improve the corrosion resistance and electrical conductivity of steel bipolar plates,surface coatings are essential.Metal nitride coatings,metal carbide coatings,polymer coatings and carbon-based coatings have been introduced in recent years.Carbon-based coatings,mainly including a-C(amorphous Carbon),Ta-C(Tetrahedral amorphous carbon)and DLC(diamond-like carbon),have attracted considerable attention from both academia and industry,owing to their superior performance,such as chemical inertness,mechanical hardness and electrical conductivity.However,Ta-C films as protective coating of PEMFCs have been rarely reported,due to the difficulty in production for industrial application.In this paper,multi-layer Ta-C composite films were produced by using customized industrial-scale vacuum equipment to address those issues.[Methods]Multiple layered Ta-C coatings were prepared by using PIS624 equipment,which assembled filtered cathodic arc evaporation,ion beam and magnetron sputtering into one equipment,while SS304 and silicon specimens were used as substrate for testing and analysis.Adhesion layer and intermediate layer were deposited by using magnetron sputtering at deposition temperature of 150℃and pressure of 3×10^(−1) Pa,while the sputtering current was set to be 5 A and bias power to be 300 V.The Ta-C layer was coated at arc current of 80-100 A,bias voltage of 1500 V and gas flow of 75 sccm.A scanning electron microscope(CIQTEK SEM3200)was used to characterize surface morphology,coating structure and cross-section profile of the coatings.Raman spectrometer(LabRam HR Evolution,HORIBA JOBIN YVON)was used to identify the bonding valence states.Electrochemical tests were performed by using an electrochemical work station(CHI760,Shanghai Chenhua Instrument Co.,Ltd.),with the traditional three electrode system,where saturated Ag/AgCl and platinum mesh were used as the reference electrode and counter electrode,respectively.All samples were mounted in plastic tube and sealed with epoxy resin,with an exposure area of 2.25 cm^(2),serving as the working electrode.Electrochemical measurements were carried out in simulated PEMFCs cathode environment in 0.5 mol·L^(−1) H_(2)SO_(4)+5 ppm F−solution,at operating temperature of 70℃.As the cathode environment was harsher than the anode environment,all the samples are stabilized at the open-circuit potential(OCP)for approximately 30 min before the EIS measurements.ICR between bipolar plates and GDL was a key parameter affecting performance of the PEMFCs stack.The test sample sandwiched between 2 pieces of carbon paper(simulate gas diffusion layer,GDL)was placed between 2 gold-plated copper electrodes at a compaction pressure of 1.4 MPa,which was considered to be the conventional compaction pressure in the PEMFCs.Under the same conditions,the resistance of a single carbon paper was measured as well.The ICR was calculated according to the formula ICR=1/2(R2−R1)×S,where S was the contact area between GDL and coated stainless steel BPPs.All data of ICR were measured three times for averaging.[Results]The coatings deposited by filtered cathodic arc technology were compact and smooth,which reduced coating porosity and favorable to corrosion resistance.The coating thickness of adhesion and intermediate layers were 180 nm,while the protective Ta-C coating thickness was about 300 nm,forming multiple coating to provide stronger protection for metal bipolar plates.Cr,Ti,Nb and Ta coatings were selected as adhesion layers for comparison.According to electrochemical test,Ta and Nb coatings have higher corrosion resistance.However,Ta and Nb materials would be costly when they are used for mass production.Relatively,Cr and Ti materials were cost effective.Hence,a comprehensive assessment was indispensable to decide the materials to be selected as adhesion layer.Ta-TiN and Ti-TiN combined adhesion and intermediate layer exhibited stronger corrosion resistance,with the corrosion current to be less than 10^(−6) A·cm^(−2).Ta-C protective coating deposited by using filtered cathodic arc technology indicated displayed higher corrosion resistance,with the average corrosion density to be about 1.26×10^(−7) A·cm^(−2).Ta-C coating also shown larger contact angle,with the highest hydrophobicity,which was one of the important advantages for Ta-C,in terms of corrosion resistance.According to Raman spectroscopy,the I(D)/I(G)=549.8/1126.7=0.487,with the estimated fraction of sp^(3) bonding to be in the range of 5154%.The intermediate layer TiN has higher conductivity than the CrN layer.Considering cost,corrosion performance and ICR result,the Ti-TiN layer combination is recommended for industrial scale application.[Conclusions]Multiple layer coating structure of Ta-C film had stronger corrosion resistance;with more than 50%sp^(3) content,while it also had larger water contact angle and higher corrosion resistance than DLC film.The filtered arcing deposition technology was able to make the film to be more consistent and stable than normal arcing technology in terms of the preparation of Ta-C.The coating displayed corrosion density of 1.26×10^(−7) A·cm^(−2) and ICR of less than 5 mΩ·cm^(2),far beyond technical target of 2025 DOE(US Department of Energy).This indicated that the mass-production scale coating technology for PEMFC bipolar plates is highly possible.
基金supported by National Natural Science Foundation of China(Nos.82322015,82171006)Sichuan Province Youth Science and Technology Innovation Team(No.2022JDTD0021)+3 种基金Sichuan Science and Technology Program(No.2022NSFSC0002)West China Hospital of Stomatology Sichuan University(No.RCDWJS2024-3)Sichuan Science and Technology Program(Nos.2023NSFSC1706,2024NSFSC1589)Postdoctoral Science Foundation of China(No.BX20220220)。
文摘Osteogenic ability impairment and myelosuppression are common complications of chemotherapy and many chemotherapeutics can affect the skeletal system.Skeletal system protection is necessary for cancer chemotherapy.In this study,osteogenic growth peptide(OGP)and tetrahedral framework nucleic-acid nanostructures(tFNAs)are combined to form a peptide-DNA complex OGP-tFNAs,which aims to combine the positive biological effect on tissue protection and regeneration.The bone marrow protection and bone formation effect of OGP-tFNAs are investigated in chemotherapy-induced myelosuppressive mice.The results show that OGP-tFNAs could reduce the cell damage degree from 5-fluorouracil(5-FU)in vitro and maintained the osteogenic differentiation potential.Furthermore,OGP-tFNAs accelerate bone defect regeneration in myelosuppressive mice.In conclusion,OGP-tFNAs could protect the osteogenic differentiation potential of bone marrow stromal cells(BMSCs)from 5-FU injury and maintain the bone formation ability of myelosuppressive mice suffering from chemotherapy.
基金supported by National Natural Science Foundation of China(Nos.81874027,82370929,81970916)Sichuan Science and Technology Program(Nos.2019YFQ0003,2022YFS0051,2022NSFSC0002)+3 种基金Sichuan Province Youth Science and Technology Innovation Team(No.2022JDTD0021)Research and Develop Program,West China Hospital of Stomatology Sichuan University(Nos.RD03202302,RCDWJS2024–1)135-project for disciplines of excellenceClinical Research Incubation project of West China Hospital of Sichuan University(No.2021HXFH036)。
文摘Neuropathic pain(NP)is one of the most common pathological pain types and is associated with limited treatment options;moreover,it affects patients’quality of life and causes a heavy social burden.Despite the emphasis on inhibiting neuronal apoptosis to relieve NP,the crucial role of a neuroinflammation is often overlooked.Therefore,refocusing on the regulation of microglia polarization to create a more conducive environment for neuron holds great potential in NP treatment.In recent years,small interfering RNAs(siRNAs)had become an attractive therapeutic option.However,an efficient loading and delivery system for siRNA is still in lack.In our study,a nanostructured tetrahedral framework nucleic acid loaded with the small interfering RNA C–C chemokine receptor 2(T-siCCR2)was successfully designed and synthesized for use in NP rat model in vivo and in a lipopolysaccharide(LPS)-induced inflammatory environment in vitro.This nanoscale complex is endowed with structural stability and satisfactory delivery efficiency while assuring the silencing effect of siRNA-CCR2.In vivo,T-siCCR2 treatment exhibited favorable effects on pain relief and functional improvement in the NP animal model by directly targeting microglia.In vitro,T-siCCR2 counteracts LPS-induced inflammation by inhibiting the differentiation of microglia toward the M1 phenotype,thus playing a neuroprotective role.RNA sequencing was subsequently performed to elucidate the underlying mechanism involved.These results indicate that T-siCCR2 may serve as a potential treatment option for NP in the future.
基金supported by the National Natural Science Foundation of China(No.82101077)Sichuan Science and Technology Program(No.2023NSFSC1516)+2 种基金Postdoctoral Science Foundation of China(Nos.2021M692271,2023T160455)West China School/Hospital of Stomatology Sichuan University,No.RCDWJS2023-5,Fundamental Research Funds for the Central UniversitiesResearch and Develop Program,West China Hospital of Stomatology Sichuan University.
文摘Diabetic kidney disease(DKD)is recognized as a severe complication in the development of diabetes mellitus(DM),posing a significant burden for global health.Major characteristics of DKD kidneys include tubulointerstitial oxidative stress,inflammation,excessive extracellular matrix deposition,and progressing renal fibrosis.However,current treatment options are limited and cannot offer enough efficacy,thus urgently requiring novel therapeutic approaches.Tetrahedral framework nucleic acids(tFNAs)are a novel type of self-assembled DNA nanomaterial with excellent structural stability,biocompatibility,tailorable functionality,and regulatory effects on cellular behaviors.In this study,we established an in vitro high glucose(HG)-induced human renal tubular epithelial cells(HK-2 cells)pro-fibrogenic model and explored the antioxidative,anti-inflammatory,and antifibrotic capacity of tFNAs and the potential molecular mechanisms.tFNAs not only effectively alleviated oxidative stress through reactive oxygen species(ROS)-scavenging and activating the serine and threonine kinase(Akt)/nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)signaling pathway but also inhibited the production of proinflammatory factors such as tumor necrosis factor(TNF-α),interleukin-1β(IL-1β),and interleukin-6(IL-6)in diabetic HK-2 cells.Additionally,tFNAs significantly downregulated the expression of Collagen I andα-smooth muscle actin(α-SMA),two representative biomarkers of pro-fibrogenic myofibroblasts in the renal tubular epithelial-mesenchymal transition(EMT).Furthermore,we found that tFNAs exerted this function by inhibiting the Wnt/β-catenin signaling pathway,preventing the occurrence of EMT and fibrosis.The findings of this study demonstrated that tFNAs are naturally endowed with great potential to prevent fibrosis progress in DKD kidneys and can be further combined with emerging pharmacotherapies,providing a secure and efficient drug delivery strategy for future DKD therapy.
基金Project supported by the National Key R&D Program of China (Grant No. 2022YFA1403800)the National Natural Science Foundation of China (Grant Nos. 12250008 and 12188101)+1 种基金the Project for Young Scientists in Basic Research (Grant No. YSBR-059)performed in part at the Aspen Center for Physics, supported by the National Natural Science Foundation of China (Grant No. PHY2210452)。
文摘We theoretically study the effect of a uniform orbital magnetic field on spin waves in a triangular lattice tetrahedral antiferromagnetic insulator without spin–orbit coupling. Through symmetry analysis and microscopic calculation, we show that the optical spin wave mode at the Brillouin zone center can acquire a small orbital magnetic moment, although it exhibits no magnetic moment from the Zeeman coupling. Our results are potentially applicable to intercalated van der Waals materials and twisted double-bilayer graphene.
基金supported by the National Natural Science Foundation of China (Nos. 82101077, 82370929)Sichuan Science and Technology Program (Nos. 2023NSFSC1516, 2023NSFSC1706)+3 种基金Postdoctoral Science Foundation of China (Nos. 2021M692271, 2023T160455, BX20220220, 2022M722251)West China School/Hospital of Stomatology Sichuan University (No. RCDWJS2023–5)Fundamental Research Funds for the Central UniversitiesResearch and Develop Program, West China Hospital of Stomatology Sichuan University
文摘Hyperglycemia resulting from diabetes mellitus(DM)exacerbates osteoporosis and fractures,damaging bone regeneration due to impaired healing capacity.Stem cell therapy offers the potential for bone repair,accelerating the healing of bone defects by introducing stem cells with osteogenic differentiation ability.Dental follicle stem cells(DFSCs)are a newly emerging type of dental stem cells that not only have the potential for multipotent differentiation but also hold easy accessibility and can stand longterm storage.However,DM-associated oxidative stress and inflammation elevate the risk of DFSCs dysfunction and apoptosis,diminishing stem cell therapy efficacy.Recent nanomaterial advances,particularly in DNA nanostructures like tetrahedral framework nucleic acids(tFNAs),have been promising candidates for modulating cellular behaviors.Accumulating experiments have shown that tFNAs’cell proliferation and migration-promoting ability and induce osteogenic differentiation of stem cells.Meanwhile,tFNAs can scavenge reactive oxygen species(ROS)and downregulate the secretion of inflammatory factors by inhibiting various inflammation-related signaling pathways.Here,we applied tFNAs to modify DFSCs and observed enhanced osteogenic differentiation alongside ROS scavenging and anti-inflammatory effects mediated by suppressing the ROS/mitogen-activated protein kinases(MAPKs)/nuclear factor kappa-B(NF-κB)signaling pathway.This intervention reduced stem cell apoptosis,bolstering stem cell therapy efficacy in DM.Our study establishes a simple yet potent tFNAs-DFSCs system,offering potential as a bone repair agent for future DM treatment.
基金the China Postdoc Council(OCPC)for the financial support of Postdoctoral International Exchange Program(No.YJ20210095)the financial support from the National Natural Science Foundation of China(No.22078150)+3 种基金National Key R&D Program of China(No.2021YFC2101904)the Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture(No.XTB2201)the Top-Notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)。
文摘The innovation in polymer design to rival conventional polyethylene glycol(PEG)is an important approach to achieving a more sustainable society.Here,cyclic PEG-like polycarbonates having high molecular weight(4.4–49.5 kg/mol)were enabled through zwitterionic ring-opening polymerization(ZROP)of macrocyclic carbonates(MCs)mediated by N-heterocyclic carbene(NHC).The thermodynamic behavior of polymerization depends on the ring size of monomers.During this process,the ZROP of 11-membered MC was driven by the change of enthalpy(ΔH_(p))which differed from the ZROP of 14-membered MC driven by the entropic change(ΔS_(p)).Cyclic polycarbonates depicted improved thermostability(T_(d5%)≥204℃)and higher glass transition temperatures(T_(g)>–40℃)in comparison to their linear analogues(T_(d5%)≤185℃,T_(g)~–50℃).In addition,the mechanism of ZROP of MC was addressed through computational study.A distinct mechanism of polymerization distinguishable from the well-known NHC-mediated ZROP of cyclic esters was revealed,where the zwitterion from nucleophilic addition to MC,i.e.tetrahedral intermediate,cannot be ring-opened probably due to the delocalization of negative charge on the carbonate group,but serves as an active center for the polymerization.In comparison to PEG,the attained polymer demonstrated comparable hydrophilic and biocompatible properties,as revealed by the results of contact angle and in vitro cytotoxicity studies,suggesting that cyclic polycarbonate hold the promise as the alternative of PEG.
基金supported by National Key R&D Program of China(No.2019YFA0110600)National Natural Science Foundation of China(Nos.82370929,81970916)+3 种基金Sichuan Science and Technology Program(No.2022NSFSC0002)Sichuan Province Youth Science and Technology Innovation Team(No.2022JDTD0021)Research and Develop Program,West China Hospital of Stomatology Sichuan University(No.RD03202302)Science and technology support plan project of Guizhou Provincial Department of science and technology(No.Qiankehe support[2022]General264)。
文摘This article reviews the latest research advances of tetrahedral framework nucleic acid(t FNA)-based systems in their fabrication,modification,and the potential applications in biomedicine.TFNA arises from the synthesis of four single-stranded DNA chains.Each chain contains brief sequences that complement those found in the other three,culminating in the creation of a pyramid-shaped nanostructure of approximately 10 nanometers in size.The first generation of t FNA demonstrates inherent compatibility with biological systems and the ability to permeate cell membrane effectively.These attributes translate into remarkable capabilities for regulating various cellular biological processes,fostering tissue regeneration,and modulating immune responses.The subsequent evolution of t FNA introduces enhanced adaptability and a relatively higher degree of biological stability.This advancement encompasses structural modifications,such as the addition of functional domains at the vertices or side arms,integration of low molecular weight pharmaceuticals,and the implementation of diverse strategies aimed at reversing multi-drug resistance in tumor cells or microorganisms.These augmentations empower t FNA-based systems to be utilized in different scenarios,thus broadening their potential applications in various biomedical fields.
基金supported by National Natural Science Foundation of China(No.82301030)China Postdoctoral Science Foundation(No.2022M712384)+2 种基金Tianjin Education Commission Research Project(No.2021KJ244)Tianjin Health Science and Technology Project(No.TJWJ2021QN038)Tianjin Key Medical Discipline(Specialty)Construction Project(No.TJYXZDXK-038A).
文摘Diabetes mellitus considerably affects bone marrow mesenchymal stem cells(BMSCs),for example,by inhibiting their proliferation and differentiation potential,which enhances the difficulty in endogenous bone regeneration.Hence,effective strategies for enhancing the functions of BMSCs in diabetes have farreaching consequences for bone healing and regeneration in diabetes patients.Tetrahedral framework nucleic acids(tFNAs)are nucleic acid nanomaterials that can autonomously enter cells and regulate their behaviors.In this study,we evaluated the effects of tFNAs on BMSCs from diabetic rats.We found that tFNAs could promote the proliferation,migration,and osteogenic differentiation of BMSCs from rats with type 2 diabetes mellitus,and inhibited cell senescence and apoptosis.Furthermore,tFNAs effectively scavenged the accumulated reactive oxygen species and activated the suppressed protein kinase B(Akt)signaling pathway.Overall,we show that tFNAs can recover the proliferation and osteogenic potential of diabetic BMSCs by alleviating oxidative stress and activating Akt signaling.The study provides a strategy for endogenous bone regeneration in diabetes and also paves the way for exploiting DNA-based nanomaterials in regenerative medicine.
基金financially supported by the National Natural Science Foundation of China(Grant No.52272253)“Lingyan”Research and Development Plan of Zhejiang Province(Grant No.2022C01071)+2 种基金Low Cost Cathode Material(Grant No.TC220H06P)the Natural Science Foundation of Ningbo(Grant No.202003N4030)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2022299)
文摘The undesirable capacity loss after first cycle is universal among layered cathode materials,which results in the capacity and energy decay.The key to resolving this obstacle lies in understanding the effect and origin of specific active Li sites during discharge process.In this study,focusing on Ah-level pouch cells for reliability,an ultrahigh initial Coulombic efficiency(96.1%)is achieved in an archetypical Li-rich layered oxide material.Combining the structure and electrochemistry analysis,we demonstrate that the achievement of high-capacity reversibility is a kinetic effect,primarily related to the sluggish Li mobility during oxygen reduction.Activating oxygen reduction through small density would induce the oxygen framework contraction,which,according to Pauli repulsion,imposes a great repulsive force to hinder the transport of tetrahedral Li.The tetrahedral Li storage upon deep oxygen reduction is experimentally visualized and,more importantly,contributes to 6%Coulombic efficiency enhancement as well as 10%energy density improvement for pouch cells,which shows great potentials breaking through the capacity and energy limitation imposed by intercalation chemistry.
文摘Three new maleate compounds have been synthesized and studied by infrared,25Mg NMR(Nuclear Magnetic Resonance)Spectroscopy and UV(Ultraviolet)-visible spectroscopies.The suggested structures for the three complexes are discrete with NH-Cl hydrogen bonds.The maleate anion is monochelating(compound 1 and 2)and bichelating(compound 3).The environment tin(IV)and magnesium center are octahedral and the zinc center environment is tetrahedral.In all the suggested structures,when extra hydrogen bonds are considered,supramolecular architectures are obtained.
基金Plasseraud,ICMUB UMR CNRS 6302,University of Burgundy,Faculty of Sciences,Dijon,France.
文摘One new hydrogenosuccinate and two succinate adduct and complex have been synthesized and studied by infrared,UV-Visible and NMR(Nuclear Magnetic Resonance Spectroscopy)^(119)Sn spectroscopies.The suggested structure is discrete,the hydrogenosuccinate behaving as a monodentate ligand or only involved in hydrogen bonding,the environment around the magnesium centre being triangular(compound 3).The succiate anion is a monochelating ligand(compound 1 and 2).In all the suggested structures,when extra hydrogen bonds are considered,supramolecular architectures are obtained(compound 2 and 3).
文摘By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.
文摘Three new salicylate complexes and derivatives have been synthesized and studied by infrared, 119Sn NMR and UV-visible spectroscopies. The suggested structures for the two compounds are discrete with NH-O and NH-Cl hydrogen bonds. The salicylate oxyanion is monochelating for the first salicylate compound with an octahedral tin (IV) centre and monodentate for the second salicylate compound, the environments around the tin centre being tetrahedral. For the cooper complex, the salicylate ligand is monochelating and the environments around the copper atom centre are tetrahedral.
基金Supported by National Natural Science Foundation of China(No.60875046)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1109)+5 种基金the Key Project of Chinese Ministry of Education(No.209029)the Program for Liaoning Excellent Talents in University(No.LR201003)the Program for Liaoning Science and Technology Research in University(No.LS2010008,2009S008,2009S009, LS2010179)the Program for Liaoning Innovative Research Team in University(Nos.2009T005, LT2010005, LT2011018)Natural Science Foundation of Liaoning Province(201102008)"Liaoning Bai Qian Wan Talents Program(2010921010, 2011921009)"
文摘This paper presents a reconstruction algorithm to build a surface mesh approximating an object from an unorganized point sampling of the boundary object. It combines 3D Delaunay tetrahedralization and mesh-growing method and uses only once Delau- nay triangulation. It begins with 3D Delaunay triangulation of the sampling. Then initialize the surface mesh with seed facets se- lected from Delaunay triangulation. Selection is based on the angle formed by the circumscribing ball of incident tetrahedral. Finally, grow until complete the surface mesh based on some heuristic rules. This paper shows several experimental results that demonstrate this method can handle open and close surfaces and work efficiently on various object topologies except non-manifold surface with self-intersections. It can reproduce even the smallest details of well-sampled surfaces but not work properly in every under-sampled situation that point density is too low.
基金This research is supported by the Dutch Technology Foundation STW,which is part of the Netherlands Organization for Scientific Research(NWO),and which is partly funded by the Ministry of Economic Affairs(project codes:11300 and 11185).
文摘For storing and modeling three-dimensional(3D)topographic objects(e.g.buildings,roads,dykes,and the terrain),tetrahedralizations have been proposed as an alternative to boundary representations.While in theory they have several advantages,current implementations are either not space efficient or do not store topological relationships(which makes spatial analysis and updating slow,or require the use of an expensive 3D spatial index).We discuss in this paper an alternative data structure for storing tetrahedralizations in a database management system(DBMS).It is based on the idea of storing only the vertices and stars of edges;triangles and tetrahedra are represented implicitly.It has been used previously in main memory,but not in a DBMS.We describe how to modify it to obtain an efficient implementation in a DBMS,and we describe how it can be used for modeling 3D topography.As we demonstrate with different real-world examples,the structure is compacter than known alternatives,it permits us to store attributes for any primitives,and has the added benefit of being topological,which permits us to query it efficiently.The structure can be easily implemented in most DBMS(we describe our implementation in PostgreSQL),and we present some of the engineering choices we made for the implementation.
基金supported by the 973 Program of China 2005CB321702China NSF 10531080.
文摘Local mesh refinement is one of the key steps in the implementations of adaptive finite element methods. This paper presents a parallel algorithm for distributed memory parallel computers for adaptive local refinement of tetrahedral meshes using bisection. This algorithm is used in PHG, Parallel Hierarchical Grid Chttp：//lsec. cc. ac. cn/phg/）, a toolbox under active development for parallel adaptive finite element solutions of partial differential equations. The algorithm proposed is characterized by allowing simukaneous refinement of submeshes to arbitrary levels before synchronization between submeshes and without the need of a central coordinator process for managing new vertices. Using the concept of canonical refinement, a simple proof of the independence of the resulting mesh on the mesh partitioning is given, which is useful in better understanding the behaviour of the biseetioning refinement procedure.
基金supported by National Key R&D Program of China (2019YFA0110600)National Natural Science Foundation of China (81970986, 81771125)
文摘Osteoarthritis, a disorder characterized by articular cartilage deterioration, varying degrees of inflammation, and chondrocyte apoptosis, is the most common chronic joint disease. To slow or reverse its progression, inflammation should be inhibited, and chondrocyte proliferation should be promoted. Tetrahedral framework nucleic acids can be internalized by chondrocytes(even inflammatory chondrocytes) and can enhance their proliferation and migration. Wogonin, a naturally occurring flavonoid,suppresses oxidative stress and inhibits inflammation. In this study, tetrahedral framework nucleic acids were successfully selfassembled and used to load wogonin. We confirmed the effective formation of tetrahedral framework nucleic acid/wogonin complexes by dynamic light scattering, zeta potential analysis, transmission electron microscopy, and fluorescence spectrophotometry. Tetrahedral framework nucleic acids, wogonin, and especially tetrahedral framework nucleic acid/wogonin complexes effectively alleviated inflammation in vitro and in vivo and prevented cartilage destruction. In addition, these materials remarkably downregulated the expression of inflammatory mediators and matrix metalloproteinases, upregulated chondrogenic markers, and promoted tissue inhibitor of metalloproteinase 1 and B-cell lymphoma 2 expression. In vivo, after treatment with tetrahedral framework nucleic acid/wogonin complexes, the bone mineral density in regenerated tissues was much higher than that found in the untreated groups. Histologically, the complexes enhanced new tissue regeneration, significantly suppressed chondrocyte apoptosis, and promoted chondrogenic marker expression. They also inhibited cell apoptosis, increased chondrogenic marker expression, and suppressed the expression of inflammatory mediators in osteoarthritis. Therefore, we believe that tetrahedral framework nucleic acid/wogonin complexes can be used as an injectable form of therapy for osteoarthritis.
基金Project supported by the National Natural Science Foundation of China (No.69833010)
文摘The Tetrahedral Network(TEN) is a powerful 3-D vector structure in GIS, which has a lot of advantages such as simple structure, fast topological relation processing and rapid visualization. The difficulty of TEN application is automatic creating data structure. Although a raster algorithm has been introduced by some authors, the problems in accuracy, memory requirement, speed and integrity are still existent. In this paper, the raster algorithm is completed and a vector algorithm is presented after a 3-D data model and structure of TEN have been introducted. Finally, experiment, conclusion and future work are discussed.
