H. Lakhlifi, Y. El Jabbar, A. Natik, M. Benchikhi, H. Lassri, L. Er-Rakho, R. El Ouatib
Molybdenum-based binary oxides AMoO4 (A= Co2+ and Mn2+) have been successfully synthesized using the sol-gel method. The prepared nanopowders were characterized by means of thermal analysis (TGA/DTA), X-ray diffraction (XRD) and Rietveld refinement data. Scanning electron microscope (SEM) of the powders obtained from cobalt nitrate (G1 gel) showed porous agglomerate that formed cages, which came from the degassing in several stages. Meanwhile, pre-sintering was observed in the powders obtained from cobalt chloride (G2 gel). The transmission electron microscopy (TEM) of CoMoO4 molybdate showed quasi-spherical particles with nanometric size range of 10-60 nm. Raman spectroscopy revealed the presence of the vibrational modes O-Metal, Metal-O-Metal, and O-Metal-O, which confirm the formation of the desired phase. Based on the optical band-gap energy (Eg=1.98 eV), the monoclinic b-MnMoO4 is a semiconductor material. The theoretical magnetic moment of the b-MnMoO4 sample is approximately μtheorical = 5.00049 μB. The photocatalytic degradation process of Indigo dye was investigated using cobalt molybdate (CoMoO4) as a photocatalyst, this process was followed by UV–vis absorption spectroscopy analyzes. The photocatalytic activity tests under UV light irradiation show a 45% of discoloration efficiency after 125 min. The addition of H2O2 increases this rate to 74 %.
{"title":"Rietveld Refinement, Morphology Analysis, Electronic, Magnetic, Optical and Photocatalytic Performance of AMoO 4 (A= Co 2+ and Mn 2+) Nanopowders Synthesized by Sol-Gel Method","authors":"H. Lakhlifi, Y. El Jabbar, A. Natik, M. Benchikhi, H. Lassri, L. Er-Rakho, R. El Ouatib","doi":"10.2139/ssrn.3914314","DOIUrl":"https://doi.org/10.2139/ssrn.3914314","url":null,"abstract":"Molybdenum-based binary oxides AMoO4 (A= Co2+ and Mn2+) have been successfully synthesized using the sol-gel method. The prepared nanopowders were characterized by means of thermal analysis (TGA/DTA), X-ray diffraction (XRD) and Rietveld refinement data. Scanning electron microscope (SEM) of the powders obtained from cobalt nitrate (G1 gel) showed porous agglomerate that formed cages, which came from the degassing in several stages. Meanwhile, pre-sintering was observed in the powders obtained from cobalt chloride (G2 gel). The transmission electron microscopy (TEM) of CoMoO4 molybdate showed quasi-spherical particles with nanometric size range of 10-60 nm. Raman spectroscopy revealed the presence of the vibrational modes O-Metal, Metal-O-Metal, and O-Metal-O, which confirm the formation of the desired phase. Based on the optical band-gap energy (Eg=1.98 eV), the monoclinic b-MnMoO4 is a semiconductor material. The theoretical magnetic moment of the b-MnMoO4 sample is approximately μtheorical = 5.00049 μB. The photocatalytic degradation process of Indigo dye was investigated using cobalt molybdate (CoMoO4) as a photocatalyst, this process was followed by UV–vis absorption spectroscopy analyzes. The photocatalytic activity tests under UV light irradiation show a 45% of discoloration efficiency after 125 min. The addition of H2O2 increases this rate to 74 %.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73583011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bin‐Cheng Wang, Qianqian Wang, N. Lu, Bo Sun, Xiubing Liang, B. Shen
The HfNbTaTiZrV refractory high-entropy alloy reinforced with 4vol.% Al2O3 displays excellent phase stability and mechanical properties at elevated temperatures. A superior compressive yield strength of 2700 MPa at room temperature, 1392 MPa at 800 °C, and 693 MPa at 1000 °C has been obtained. The improved yield strength results from multiple strengthening mechanisms caused by Al2O3 addition, including interstitial strengthening, grain boundary strengthening, and dispersion strengthening. Besides, the effects of interstitial strengthening increase with the temperature and is the main strengthening mechanism at 800 °C. These findings not only promote the development of oxide-reinforced RHEAs for challenging engineering applications but also provide guidelines for the design of refractory materials with multiple strengthening mechanisms.
{"title":"Enhanced High-Temperature Strength of HfNbTaTiZrV Refractory High-Entropy Alloys by AI 2O 3 Reinforcement","authors":"Bin‐Cheng Wang, Qianqian Wang, N. Lu, Bo Sun, Xiubing Liang, B. Shen","doi":"10.2139/ssrn.3860383","DOIUrl":"https://doi.org/10.2139/ssrn.3860383","url":null,"abstract":"The HfNbTaTiZrV refractory high-entropy alloy reinforced with 4vol.% Al<sub>2</sub>O<sub>3</sub> displays excellent phase stability and mechanical properties at elevated temperatures. A superior compressive yield strength of 2700 MPa at room temperature, 1392 MPa at 800 °C, and 693 MPa at 1000 °C has been obtained. The improved yield strength results from multiple strengthening mechanisms caused by Al<sub>2</sub>O<sub>3</sub> addition, including interstitial strengthening, grain boundary strengthening, and dispersion strengthening. Besides, the effects of interstitial strengthening increase with the temperature and is the main strengthening mechanism at 800 °C. These findings not only promote the development of oxide-reinforced RHEAs for challenging engineering applications but also provide guidelines for the design of refractory materials with multiple strengthening mechanisms.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81294658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yingjie Zhang, Tao Wei, A. Xu, P. Dayal, D.J. Gregg
As potential waste forms for immobilizing actinide-rich radioactive wastes, Eu2Ti2O7 pyrochlore glass-ceramics were fabricated via hot isostatic pressing (HIPing) at 1200 oC. The structure at the reaction interface between the glass-ceramic waste form and the stainless steel (SS) canister under HIPing conditions were carefully investigated with SEM, TEM and synchrotron single crystal X-ray diffraction (SC-XRD). The interactions at the reaction interface led to the formations of a ∼10 µm thick Cr2O3 layer as the oxidation front of the SS and a layer of a mixed oxide phase (Eu1.25SiCr0.8Ti1.2O7.5) on the glass-ceramic side of the reaction interface. The crystal structure of such a unique mixed oxide phase was revealed indubitably with a combination of synchrotron SC-XRD and TEM assisted with a FIB-SEM system. The improved structural understanding of the reaction interface will help to support the utilization of HIPing as a versatile hot consolidation process for the treatment of radioactive wastes.
{"title":"Structure Insides at the Reaction Interface Between Pyrochlore Glass-Ceramics and Stainless Steel Canister Under Hot Isostatic Pressing Conditions","authors":"Yingjie Zhang, Tao Wei, A. Xu, P. Dayal, D.J. Gregg","doi":"10.2139/ssrn.3807766","DOIUrl":"https://doi.org/10.2139/ssrn.3807766","url":null,"abstract":"As potential waste forms for immobilizing actinide-rich radioactive wastes, Eu<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> pyrochlore glass-ceramics were fabricated <i>via</i> hot isostatic pressing (HIPing) at 1200 <sup>o</sup>C. The structure at the reaction interface between the glass-ceramic waste form and the stainless steel (SS) canister under HIPing conditions were carefully investigated with SEM, TEM and synchrotron single crystal X-ray diffraction (SC-XRD). The interactions at the reaction interface led to the formations of a ∼10 µm thick Cr<sub>2</sub>O<sub>3</sub> layer as the oxidation front of the SS and a layer of a mixed oxide phase (Eu<sub>1.25</sub>SiCr<sub>0.8</sub>Ti<sub>1.2</sub>O<sub>7.5</sub>) on the glass-ceramic side of the reaction interface. The crystal structure of such a unique mixed oxide phase was revealed indubitably with a combination of synchrotron SC-XRD and TEM assisted with a FIB-SEM system. The improved structural understanding of the reaction interface will help to support the utilization of HIPing as a versatile hot consolidation process for the treatment of radioactive wastes.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80242613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ming Feng, Kang Zhang, Guoqing Sun, Yuanhao Li, Dong-dong Han, Ziyu Chen, Jiaxin Yang, Zejia Zhao, F. Song
Nb 2 AlC is a kind of ternary ceramic material whose special crystal structure makes it both the advantages of metal and ceramics. And it has good electrical conductivity and strong stability at room temperature. In this article, the saturable absorption of Nb 2 AlC based thin film have been investigated, showing that it has saturated light intensity of 0.21 MW/cm 2 and the modulation depth of 2.62%. Noise-like mode locked and Q-switched pulses output based on Nb 2 AlC thin film have been achieved in erbium-doped fiber laser cavity. The narrowest width of noise-like mode-locked pulses' envelope is 13 ns, the maximum single pulse energy is 1.5 nJ, and the full width at half-maximum (FWHM) of the narrowest coherent spike is 2.34 ps. The minimum pulse width of the Q-switched pulse is 8.6 μs and the maximum single pulse energy is 66 nJ. As far as we know, this is the first report of Nb 2 AlC's application in ultrafast optics.
{"title":"Q-Switched and Noise-Like Mode Locked Er-Doped Fiber Laser Based on Nb2AlC Saturable Absorber","authors":"Ming Feng, Kang Zhang, Guoqing Sun, Yuanhao Li, Dong-dong Han, Ziyu Chen, Jiaxin Yang, Zejia Zhao, F. Song","doi":"10.2139/ssrn.3935625","DOIUrl":"https://doi.org/10.2139/ssrn.3935625","url":null,"abstract":"Nb 2 AlC is a kind of ternary ceramic material whose special crystal structure makes it both the advantages of metal and ceramics. And it has good electrical conductivity and strong stability at room temperature. In this article, the saturable absorption of Nb 2 AlC based thin film have been investigated, showing that it has saturated light intensity of 0.21 MW/cm 2 and the modulation depth of 2.62%. Noise-like mode locked and Q-switched pulses output based on Nb 2 AlC thin film have been achieved in erbium-doped fiber laser cavity. The narrowest width of noise-like mode-locked pulses' envelope is 13 ns, the maximum single pulse energy is 1.5 nJ, and the full width at half-maximum (FWHM) of the narrowest coherent spike is 2.34 ps. The minimum pulse width of the Q-switched pulse is 8.6 μs and the maximum single pulse energy is 66 nJ. As far as we know, this is the first report of Nb 2 AlC's application in ultrafast optics.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81951773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shu-yan Cheng, Yue Li, Yifei Huang, S. Zhang, Zhao Li, H. Zhang, Liqiang Wang
An ideal keratoprosthesis scaffold should have good mechanical property, high biocompatibility, suitable corrosion and wear resistance. Due to limitation of materials, the difference of tenacity between the keratoprosthesis and the cornea often causes the exposure of keratoprosthesis materials, which results in serious complications. The cartilage has the similar biological characteristics to the cornea, no blood vessels and has certain flexibility. Although using the auricular cartilage or rib cartilage to reinforce the keratoprosthesis has been proven greatly successful, it is not possible to be individually designed and idealized. It is urgent to design a biosynthetic material for cartilage replacement to deal with predicament. We prepared and combined the decellularized cartilage extracellular matrix (DCECM) and the decellularized bone matrix (DBM), added the rabbit adipose-derived mesenchymal stem cells (rADMSCs) to construct a biosynthetic keratoprosthesis skirt. We asssessed the mechanical property, cell binding efficiency, safety and cytotoxicity, biocompatability and chondrogenic or osteogenic capacity of the DCECM/DBM-rADMSCs composite scaffold. Tests revealed the DCECM/DBM scaffold has proper elasticity, tenacity, and, is safe to cells. It’s observed that the DCECM/DBM-rADMSCs composite scaffold integrated into the recipient cornea without inflammation and rejection, while transplanted in the recipient cornea for 12 months. In particular, chondrogenesis and osteogenesis are found inside and even around the scaffold. Hence, the DCECM/DBM-rADMSCs composite scaffold coule be a potential biosynthetic skirt for keratoprosthesis or a fixed supportive scaffold to reinforce the keratoprosthesis in the treatment of end-stage corneal blindness.
{"title":"DCECM/DBM-Radmscs Composite Scaffold Acts as a Biosynthetic Keratoprosthesis Skirt with High Biocompatability for Corneal Transplantation","authors":"Shu-yan Cheng, Yue Li, Yifei Huang, S. Zhang, Zhao Li, H. Zhang, Liqiang Wang","doi":"10.2139/ssrn.3849026","DOIUrl":"https://doi.org/10.2139/ssrn.3849026","url":null,"abstract":"An ideal keratoprosthesis scaffold should have good mechanical property, high biocompatibility, suitable corrosion and wear resistance. Due to limitation of materials, the difference of tenacity between the keratoprosthesis and the cornea often causes the exposure of keratoprosthesis materials, which results in serious complications. The cartilage has the similar biological characteristics to the cornea, no blood vessels and has certain flexibility. Although using the auricular cartilage or rib cartilage to reinforce the keratoprosthesis has been proven greatly successful, it is not possible to be individually designed and idealized. It is urgent to design a biosynthetic material for cartilage replacement to deal with predicament. We prepared and combined the decellularized cartilage extracellular matrix (DCECM) and the decellularized bone matrix (DBM), added the rabbit adipose-derived mesenchymal stem cells (rADMSCs) to construct a biosynthetic keratoprosthesis skirt. We asssessed the mechanical property, cell binding efficiency, safety and cytotoxicity, biocompatability and chondrogenic or osteogenic capacity of the DCECM/DBM-rADMSCs composite scaffold. Tests revealed the DCECM/DBM scaffold has proper elasticity, tenacity, and, is safe to cells. It’s observed that the DCECM/DBM-rADMSCs composite scaffold integrated into the recipient cornea without inflammation and rejection, while transplanted in the recipient cornea for 12 months. In particular, chondrogenesis and osteogenesis are found inside and even around the scaffold. Hence, the DCECM/DBM-rADMSCs composite scaffold coule be a potential biosynthetic skirt for keratoprosthesis or a fixed supportive scaffold to reinforce the keratoprosthesis in the treatment of end-stage corneal blindness.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83389670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Debord, H. Euchner, V. Pischedda, M. Hanfland, Alfonso San-Miguel, P. Mélinon, S. Pailhès, D. Machon
A competition of point defect configurations is inherent to crystalline phases of increased structural complexity. Symmetry preserving phase transitions between them belong to the special class of isostructural transitions. Type-I silicon clathrates are crystalline complex phases whose unit cell containing a fifties of atoms consists of a 3D covalent silicon framework of face-sharing polyhedral cages encapsulating guest cations. At high pressure, an intriguing structural transition is associated to an abrupt volume reduction with no indication for any symmetry breaking. By means of isothermal high-pressure X-ray diffraction performed on single crystal of the simplest representative type-I silicon clathrates, the binary Ba8Si46, we confirm the isostructural character of the transition and identify the associated mechanism. A detailed analysis of the atomic structural parameters across the transition in combination with ab initio studies allow us to pinpoint a microscopic mechanism driven by a defect rearrangement initially present in the structure. An analysis based on the Landau theory allows to give a coherent description of the experimental observations. A discussion on the analogy between this transformation and liquid-liquid transitions is proposed.
{"title":"Isostructural Phase Transition by Point Defect Reorganization in the Binary Type-I Clathrate Ba 7.5Si 45","authors":"R. Debord, H. Euchner, V. Pischedda, M. Hanfland, Alfonso San-Miguel, P. Mélinon, S. Pailhès, D. Machon","doi":"10.2139/ssrn.3777623","DOIUrl":"https://doi.org/10.2139/ssrn.3777623","url":null,"abstract":"A competition of point defect configurations is inherent to crystalline phases of increased structural complexity. Symmetry preserving phase transitions between them belong to the special class of isostructural transitions. Type-I silicon clathrates are crystalline complex phases whose unit cell containing a fifties of atoms consists of a 3D covalent silicon framework of face-sharing polyhedral cages encapsulating guest cations. At high pressure, an intriguing structural transition is associated to an abrupt volume reduction with no indication for any symmetry breaking. By means of isothermal high-pressure X-ray diffraction performed on single crystal of the simplest representative type-I silicon clathrates, the binary Ba<sub>8</sub>Si<sub>46</sub>, we confirm the isostructural character of the transition and identify the associated mechanism. A detailed analysis of the atomic structural parameters across the transition in combination with <i>ab initio</i> studies allow us to pinpoint a microscopic mechanism driven by a defect rearrangement initially present in the structure. An analysis based on the Landau theory allows to give a coherent description of the experimental observations. A discussion on the analogy between this transformation and liquid-liquid transitions is proposed.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73775679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The complex cellular structure of additively manufactured austenitic stainless steel, SUS316L, is due to the complicated thermal cycles involved. Cellular structure results from epitaxial growth, and cellular structure morphology depends on the directions of cell growth and observation. The probability of determining a specific cellular structure morphology of additively manufactured specimens is dependent on the grain orientation due to the directional cellular structure. Therefore, the cellular structure morphology affects the Taylor factor and mechanical properties such as hardness and yield strength. Additively manufactured austenitic stainless steel exhibits anisotropic yield strengths in the building and transverse directions, which is attributed to the cellular structure morphology and Taylor factor. The equiaxed type and elongated type exhibit a lower and high Taylor factor, respectively. The transverse direction plane presents <111> and <101> textures with a high Taylor factor, whereas the building direction plane presents a <001> texture with a relatively low Taylor factor.
{"title":"Correlation between Cellular Structure Morphology and Anisotropic Yield in Additively Manufactured Austenitic Stainless Steel","authors":"D. Kim, Soo Bin Han, Y. Lee, D. Park, Hyejin Song","doi":"10.2139/ssrn.3946394","DOIUrl":"https://doi.org/10.2139/ssrn.3946394","url":null,"abstract":"The complex cellular structure of additively manufactured austenitic stainless steel, SUS316L, is due to the complicated thermal cycles involved. Cellular structure results from epitaxial growth, and cellular structure morphology depends on the directions of cell growth and observation. The probability of determining a specific cellular structure morphology of additively manufactured specimens is dependent on the grain orientation due to the directional cellular structure. Therefore, the cellular structure morphology affects the Taylor factor and mechanical properties such as hardness and yield strength. Additively manufactured austenitic stainless steel exhibits anisotropic yield strengths in the building and transverse directions, which is attributed to the cellular structure morphology and Taylor factor. The equiaxed type and elongated type exhibit a lower and high Taylor factor, respectively. The transverse direction plane presents <111> and <101> textures with a high Taylor factor, whereas the building direction plane presents a <001> texture with a relatively low Taylor factor.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89252192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
William Y. Wang, Robert N. Kent III, Stephanie A. Huang, Evan H. Jarman, Eve H. Shikanov, Christopher D. Davidson, Harrison L. Hiraki, Daphne Lin, M. A. Wall, Jae-Won Shin, W. Polacheck, A. Shikanov, Brendon M. Baker
Vascularization of large, diffusion-hindered biomaterial implants requires an understanding of how extracellular matrix (ECM) properties regulate angiogenesis. Sundry biomaterials assessed across many disparate angiogenesis assays have highlighted ECM determinants that influence this complex multicellular process. However, the abundance of material platforms, each with unique parameters to model endothelial cell (EC) sprouting presents additional challenges of interpretation and comparison between studies. In this work we directly compared the angiogenic potential of commonly utilized natural (collagen and fibrin) and synthetic dextran vinyl sulfone (DexVS) hydrogels in a multiplexed angiogenesis-on-a-chip platform. Modulating matrix density of collagen and fibrin hydrogels confirmed prior findings that increases in matrix density correspond to increased EC invasion as connected, multicellular sprouts, but with decreased invasion speeds. Angiogenesis in synthetic DexVS hydrogels, however, resulted in fewer multicellular sprouts. Characterizing hydrogel Young’s modulus and permeability (a measure of matrix porosity), we identified matrix permeability to significantly correlate with EC invasion depth and sprout diameter. Although microporous collagen and fibrin hydrogels produced lumenized sprouts in vitro, they rapidly resorbed post-implantation into the murine epididymal fat pad. In contrast, DexVS hydrogels proved comparatively stable. To enhance angiogenesis within DexVS hydrogels, we incorporated sacrificial microgels to generate cell-scale pores throughout the hydrogel. Microporous DexVS hydrogels resulted in lumenized sprouts in vitro and enhanced cell invasion in vivo . Towards the design of vascularized biomaterials for long-term regenerative therapies, this work suggests that synthetic biomaterials offer improved size and shape control following implantation and that tuning matrix porosity may better support host angiogenesis.
{"title":"Direct Comparison of Angiogenesis in Natural and Synthetic Biomaterials Reveals Matrix Porosity Regulates Endothelial Cell Invasion Speed and Sprout Diameter","authors":"William Y. Wang, Robert N. Kent III, Stephanie A. Huang, Evan H. Jarman, Eve H. Shikanov, Christopher D. Davidson, Harrison L. Hiraki, Daphne Lin, M. A. Wall, Jae-Won Shin, W. Polacheck, A. Shikanov, Brendon M. Baker","doi":"10.2139/ssrn.3793926","DOIUrl":"https://doi.org/10.2139/ssrn.3793926","url":null,"abstract":"Vascularization of large, diffusion-hindered biomaterial implants requires an understanding of how extracellular matrix (ECM) properties regulate angiogenesis. Sundry biomaterials assessed across many disparate angiogenesis assays have highlighted ECM determinants that influence this complex multicellular process. However, the abundance of material platforms, each with unique parameters to model endothelial cell (EC) sprouting presents additional challenges of interpretation and comparison between studies. In this work we directly compared the angiogenic potential of commonly utilized natural (collagen and fibrin) and synthetic dextran vinyl sulfone (DexVS) hydrogels in a multiplexed angiogenesis-on-a-chip platform. Modulating matrix density of collagen and fibrin hydrogels confirmed prior findings that increases in matrix density correspond to increased EC invasion as connected, multicellular sprouts, but with decreased invasion speeds. Angiogenesis in synthetic DexVS hydrogels, however, resulted in fewer multicellular sprouts. Characterizing hydrogel Young’s modulus and permeability (a measure of matrix porosity), we identified matrix permeability to significantly correlate with EC invasion depth and sprout diameter. Although microporous collagen and fibrin hydrogels produced lumenized sprouts <i>in vitro</i>, they rapidly resorbed post-implantation into the murine epididymal fat pad. In contrast, DexVS hydrogels proved comparatively stable. To enhance angiogenesis within DexVS hydrogels, we incorporated sacrificial microgels to generate cell-scale pores throughout the hydrogel. Microporous DexVS hydrogels resulted in lumenized sprouts <i>in vitro</i> and enhanced cell invasion in vivo . Towards the design of vascularized biomaterials for long-term regenerative therapies, this work suggests that synthetic biomaterials offer improved size and shape control following implantation and that tuning matrix porosity may better support host angiogenesis.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85932085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Helium ions implanted into metals can evolve into ordered bubbles isomorphic to the host lattice. Long-range elastic interaction is generally believed to drive the formation of bubble superlattice, but little is known about the thermodynamics at the very initial stage. Our first-principles calculations demonstrate that in molybdenum, Friedel oscillations induced by individual helium generate both potential barriers and wells for helium clustering at short He-He distances. Such repulsion and attraction at high concentration provide a thermodynamic diving force to assist lining up randomly distributed He atoms into ordered bubbles. Friedel oscillations might have general impact on solute-solute interactions in alloys.
{"title":"Friedel Oscillations and Helium Bubble Ordering in Molybdenum","authors":"W. Geng, Q. Zhan","doi":"10.2139/ssrn.3758248","DOIUrl":"https://doi.org/10.2139/ssrn.3758248","url":null,"abstract":"Helium ions implanted into metals can evolve into ordered bubbles isomorphic to the host lattice. Long-range elastic interaction is generally believed to drive the formation of bubble superlattice, but little is known about the thermodynamics at the very initial stage. Our first-principles calculations demonstrate that in molybdenum, Friedel oscillations induced by individual helium generate both potential barriers and wells for helium clustering at short He-He distances. Such repulsion and attraction at high concentration provide a thermodynamic diving force to assist lining up randomly distributed He atoms into ordered bubbles. Friedel oscillations might have general impact on solute-solute interactions in alloys.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75439354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes a new formation route for the face-centered cubic (FCC) twins at the hexagonal close-packed (HCP)/FCC interface in a deformed Ti-5at.%Al alloy. From the experimental results, an FCC band that orients in a prismatic-type (P-type) relationship with the HCP matrix is surrounded by a group of FCC lamellae that align in parallel and orient in a basal-type (B-type) orientation relationship within the HCP matrix. The high-resolution transmission electron microscopy (HRTEM) reveals a local { } twinning relation between the FCC band and the FCC lamellae at their contacting boundaries. Molecular dynamics (MD) simulations indicate that basal stacking faults (BSFs), which later evolve into the FCC lamella in a B-type OR with the HCP matrix, initiate from the misfit regions at the relaxed P-type HCP/FCC interfaces, which then provide the nucleation source for a full dislocation that continues to slip in the initial FCC grain. Repeating these two processes produce the { } twinning relation between the new-forming FCC lamella and the initial FCC grain. The lattice correspondence analysis further interprets the formation route for the { } twins proposed in the present study from the aspect of crystal geometry.
{"title":"Dislocation Induced FCC Twins at the HCP/FCC Interfaces in a Deformed Ti-5Al Alloy: Experiments and Simulations","authors":"Hao Zhang, B. Wei, X. Ou, S. Ni, K. Zhou, M. Song","doi":"10.2139/ssrn.3757769","DOIUrl":"https://doi.org/10.2139/ssrn.3757769","url":null,"abstract":"This paper proposes a new formation route for the face-centered cubic (FCC) twins at the hexagonal close-packed (HCP)/FCC interface in a deformed Ti-5at.%Al alloy. From the experimental results, an FCC band that orients in a prismatic-type (P-type) relationship with the HCP matrix is surrounded by a group of FCC lamellae that align in parallel and orient in a basal-type (B-type) orientation relationship within the HCP matrix. The high-resolution transmission electron microscopy (HRTEM) reveals a local { } twinning relation between the FCC band and the FCC lamellae at their contacting boundaries. Molecular dynamics (MD) simulations indicate that basal stacking faults (BSFs), which later evolve into the FCC lamella in a B-type OR with the HCP matrix, initiate from the misfit regions at the relaxed P-type HCP/FCC interfaces, which then provide the nucleation source for a full dislocation that continues to slip in the initial FCC grain. Repeating these two processes produce the { } twinning relation between the new-forming FCC lamella and the initial FCC grain. The lattice correspondence analysis further interprets the formation route for the { } twins proposed in the present study from the aspect of crystal geometry.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80453546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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