STEM CELLS
·
2014
·Vol. 32
·期 7
·1943-1955
·
IF 7.133
Sun Hualing,Wu Yanru,Fu Dongjie,Liu Yinchen,Huang Cui
Sirtuin 6 (SIRT6) is a NAD-dependent deacetylase involved in lifespan regulation. To evaluate the effect of SIRT6 on osteogenesis, rat bone marrow mesenchymal stem cells (rBMSCs) with enhanced or reduced SIRT6 function were developed. We observed that SIRT6 knockdown significantly reduced the mRNA levels of several key osteogenic markers in vitro, including alkaline phosphatase (ALP), Runt-related transcription factor 2 (RUNX2), and osteocalcin, while overexpression of SIRT6 enhanced their expression. Additionally, SIRT6 knockdown activated nuclear factor-κB (NF-κB) transcriptional activity and upregulated the expression of acetyl-NF-κB p65 (Lys310). The decreased osteogenic differentiation ability of rBMSCs could be partially rescued by the addition of NF-κB inhibitor BAY 11–7082. Furthermore, SIRT6 overexpression in rBMSCs combined with the use of collagen/chitosan/hydroxyapatite scaffold could significantly boost new bone formation in rat cranial critical-sized defects, as determined by microcomputed tomography and histological examination. These data confirm that SIRT6 is mainly located in the nuclei of rBMSCs and plays an essential role in their normal osteogenic differentiation, partly by suppressing NF-κB signaling. Stem Cells 2014;32:1943–1955
研究领域:
干细胞生物学
·
骨再生
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Science
·
2025
·
IF 14.1
Ningyan Cheng,Hongyu Sun,Yevheniy Pivak,Christian H. Liebscher
Copper (Cu)-based nanomaterials are one of the most efficient heterogeneous electrocatalysts for the CO 2 reduction reaction. However, their selectivity and stability are strongly determined by their morphology, crystal structure, composition, grain size, grain boundary density, etc. Hence, gaining quantitative insights into their dynamic evolution under synthesis and/or working conditions is critical for developing optimal Cu-based electrocatalysts and unveiling their structure-property relationship. In this work, the possibility of addressing these issues is demonstrated by integrating in situ liquid phase transmission electron microscopy (LP-TEM) with 4D scanning transmission electron microscopy (4D-STEM). Here, the dynamic morphology and phase evolution of Cu nanoparticles during electrodeposition and electrooxidation processes are revealed in liquid. Virtual imaging and selected area electron diffraction provide novel insights into the evolution of defective nanocrystalline Cu nanoparticles during electrodeposition. It is shown that virtual off-axis dark field imaging can be used to map the distribution of Cu 2 O and Cu within partially oxidized Cu nanoparticles, opening new opportunities for quantitatively probing electrocatalysts under operando conditions.
研究领域:
材料科学
·
电催化
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 30
·期 9
·1-8
·
IF 2.8
Qiao Xiaoguang,Dong Xin,shi Ge,He Yanjie,Pang Xinchang
The postsynthesis polymeric modifications by grafting from the active sites were the primary focus of the structurally tailored and engineered macromolecular (STEM) gels. Therefore, Reversible-deactivation radical polymerization (RDRP) techniques have been employed to more precisely tailor and tune STEM gels. In contrast to atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer polymerization (RAFT), nitroxide-mediated polymerization (NMP) is known to have the advantages of simple components and pure products. Here we report the preparation of polydimethylsiloxane (PDMS) composite gel networks through oxygen tolerance NMP process, with tert-Butyl acrylate (tBA) and fluorinated monomer 2-(Perfluorooctyl)ethyl methacrylate (FMA) as functional comonomers. Compared with conventional radical polymerization (FRP) method, composite gels prepared through NMP method showed higher swelling rate and elongation at break, which proved that the network structure formed by NMP was more uniform. In addition to better thermal stability and toughness, the dormant polymer chain could be reactivated and lead to the “living” post-modification of PDMS gel matrix.
研究领域:
材料科学
·
高分子化学
·
材料工程
✓ 已验证
产品关联
DOI
高影响因子
STEM CELLS
·
2021
·Vol. 39
·期 11
·1546-1562
·
IF 6.277
Dong Yuan,Kong Weining,An Wei
Cell-based therapeutic approaches have been proven to be effective strategies for the treatment of acute liver injury (ALI). However, widespread application of these procedures is limited by several key issues, including rapid loss of stemness in vitro, aberrant differentiation into undesirable cell types, and low engraftment in vivo. In this study, liver epithelial progenitor cells (LEPCs) were characterized and transfected with augmenter of liver regeneration (ALR). The results revealed that in ALI mice with CCl4, the transplantation of ALR-bearing LEPCs into the liver markedly protected mice against ALI by decreasing the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), thus relieving hepatic tissue injury and attenuating inflammatory infiltration. Mechanistically, the knockdown of ALR in LEPCs activated the phosphorylation of dynamin-related protein 1 (Drp1) at the S616 site and thereby enhanced mitochondrial fission. In contrast, the transfection of ALR into LEPCs significantly inhibited Drp1 phosphorylation, thereby favoring the maintenance of mitochondrial integrity and the preservation of adenosine triphosphate contents in LEPCs. Consequently, the ALR-bearing LEPCs transplanted into ALI mice exhibited substantially greater homing ability to the injured liver via the SDF-1/CXCR4 axis than that of LEPCs-lacking ALR. In conclusion, we demonstrated that the transplantation of ALR-transfected LEPCs protected mice against CCl4-induced ALI, thus offering immense curative potential in the clinic.
研究领域:
肝病学
·
干细胞生物学
·
分子生物学
·
细胞治疗
✓ 已验证
产品关联
DOI
PubMed
高影响因子
npj Computational Materials
·
2022
·Vol. 8
·期 1
·1-9
·
IF 12.256
Sha Wuxin,Guo Yaqing,Cheng Danpeng,Han Qigao,Lou Ping,Guan Minyuan,Tang Shun,Zhang Xinfang,Lu Songfeng,Cheng Shijie,Cao Yuan-Cheng
LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) has become one of the most popular cathode materials for current lithium-ion batteries due to its high-energy density and cost performance. However, the rapid capacity fading of NCM severely hinders its development and applications. Here, the single crystal NCM523 materials under different degradation states are characterized using scanning transmission electron microscopy (STEM). Then we developed a neural network model with a two-sequential attention block to recognize the crystal structure and locate defects in STEM images. The number of point defects in NCM523 is observed to experience a trend of increasing first and then decreasing in the degradation process. The space between the transition metal columns shrinks obviously, inducing dramatic capacity decay. This analysis sheds light on the defect evolution and chemical transformation correlated with layered material degradation. It also provides interesting hints for researchers to regenerate the electrochemical capacity and design better battery materials with longer life.
研究领域:
材料科学
·
电化学
·
人工智能
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 37
·14858-14864
·
IF 5.7
Qiang Liu,Jingnan Wang,Kaiheng Zhao,Yongan Yang,Xi Wang
Due to their well-defined geometric and electronic structures and fully exposed active sites, single-atom catalysts (SACs) exhibit significantly enhanced catalytic activity in the field of catalysis. However, the controllable synthesis of SACs, particularly in a simple and scalable manner, presents formidable challenges. Here, we report the general synthesis of SACs containing Co, Ni, Cu, and Zn using a direct impregnation method. Atomically dispersed transition metal atoms over zeolite supports are confirmed by integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy. Detailed studies reveal that the dispersion process originates from the trapping of metal atoms by silane nests. Notably, the Co-SAC catalyst demonstrated superior catalytic performance in the industrially significant propane dehydrogenation reaction. This synthetic strategy is straightforward and amenable to large-scale production of thermally stable SACs for industrial applications.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 30
·21799-21807
·
IF 3.9
Yijin Sheng,Fangxu Hu,Yu Wu,De Li,Wenting Ji,Yong Chen
The electrochemical oscillation in Li-ion batteries has been reported for two-phase electrode materials of Li4Ti5O12 and LiCrTiO4, which is originated from the group-by-group phase transition in a multi-particle electrode. For both Li4Ti5O12 and LiCrTiO4, the electrochemical oscillation exhibits usually during charging, while rarely for discharging. Herein, a series of Zr-modified Li4Ti5O12 samples are prepared by using the spray-drying combined with high-temperature sintering method, and the electrochemical oscillation is observed during not only the charging process, but also the discharging process, which gradually grows up and then disappears by increasing the Li content. Compared with Li4Ti5O12, the specific capacity of Zr-modified Li4Ti5O12 decreases gradually by increasing the Zr/Ti ratio, owing to the impurity phases. According to the XRD, XPS and STEM results, the Zr element tends to accumulate on the surface to form ZrO2 nanoparticles, rather than dope into the bulk phase of Li4Ti5O12, which makes Li4Ti5O12 particles well dispersive. In contrast to the Li deficiency for only charging, the electrochemical oscillation during both charging and discharging should be attributed to the Li excess, but too much Li2TiO3 phase will suppress the electrochemical oscillation. Therefore, the Li excess can induce the electrochemical oscillation during both charging and discharging of Zr-modified Li4Ti5O12, which can be adopted to investigate the electrochemical oscillation of other materials in LIBs.
研究领域:
材料科学
·
电化学
·
电池技术
·
纳米技术
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yunning Chen,Renquan Guan,Xueying Cheng,Jie Zhao,Zhengkai Wu,Yan Wang,Qingkun Shang,Yingnan Sun
In this paper, two surface oxygen vacancy-rich TiO 2 composite photocatalysts were successfully constructed by solid thermal reduction ((R-Vo)TiO 2 ) and bimetallic doping (Nd-Fe-(D-Vo)TiO 2 ). The oxygen vacancies were characterized in detail using XPS, Raman, EPR and STEM. The results show that the excellent photocatalytic performance of Nd-Fe-(D-Vo)TiO 2 deriving from its doping energy and surface oxygen vacancies. Nd-Fe-(D-Vo)TiO 2 could degrade 58 % of phenol within 120 min, which was much greater than 15 % of TiO 2 and 27 % of (R-Vo)TiO 2 . Three composite photocatalysts, TiO 2 @EA, (R-Vo)TiO 2 @EA and Nd-Fe-(D-Vo) TiO 2 @EA, with better visible light absorption and photocatalytic performance were further obtained by bonding ellagic acid (EA) to the surface of TiO 2 . Nd-Fe-(D-Vo)TiO 2 @EA could almost completely degrade ethinyl estradiol within 20 min with a high minimization degree of 84 %. The possible sites of ethinyl estradiol attacked by free radicals were predicted by theoretical calculation combining with high-resolution mass spectrometry analysis, and the possible degradation mechanism was proposed.
研究领域:
环境科学
·
材料科学
·
化学工程
·
光化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Bio
·
2023
·
IF 8.2
Tingting Gao,Xiyuan Zhao,Jie Hao,Yao Tian,Huike Ma,Wenjing Liu,Bin An,Faguo Sun,Shasha Liu,Baojie Guo,Shuaishuai Niu,Zhongwen Li,Chenxin Wang,Yukai Wang,Guihai Feng,Liu Wang,Wei Li,Jun Wu,Meijin Guo,Qi Zhou,Qi Gu
Mesenchymal stromal cells (MSCs) derived from human embryonic stem cells (hESCs) are a desirable cell source for cell therapy owing to their capacity to be produced stably and homogeneously in large quantities. However, a scalable culture system for hPSC-derived MSCs is urgently needed to meet the cell quantity and quality requirements of practical clinical applications. In this study, we developed a new microcarrier with hyaluronic acid (HA) as the core material, which allowed scalable serum-free suspension culture of hESC-derived MSCs (IMRCs). We used optimal microcarriers with a coating collagen concentration of 100 μg/mL or concave-structured surface (cHAMCs) for IMRC amplification in a stirred bioreactor, expanding IMRCs within six days with the highest yield of over one million cells per milliliter. In addition, the harvested cells exhibited high viability, immunomodulatory and regenerative therapeutic promise comparable to monolayer cultured MSCs while showing more increased secretion of extracellular matrix (ECM), particularly collagen-related proteins. In summary, we have established a scalable culture system for hESC-MSCs, providing novel approaches for future cell therapies.
研究领域:
干细胞生物学
·
组织工程
·
生物医学工程
·
细胞治疗
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 9
·1416
·
IF 5.719
Yining Jia,Rong Huang,Ruijuan Qi
Numerous efforts have been devoted to realizing the high loading and full utilization of single-atom catalysts (SACs). As one of the representative methods, atom migration-trapping (AMT) is a top-down strategy that converts a certain volume of metal nanoparticles (NPs) or metal-based precursors into mobile metal species at high temperature, which can then be trapped by suitable supports. In this study, high-loading iron single atoms anchored onto carbon matrix/g-C3N4hybrid supports were obtained through a single-atom migration-trapping method based on metal–organic framework (MOF) pyrolysis. It is confirmed, by high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), that the Fe(acac)3precursor is reduced to Fe single atoms (SAs), which are not only anchored onto the original N-doped carbon (NC), but also onto g-C3N4, with an Fe-N coordination bond. Further electrochemical results reveal that Fe-C3N4-0.075 possesses a better half-wave potential of 0.846 V and onset potential of 0.96 V compared to Fe-N-C, the product obtained after pyrolysis of Fe(acac)3@ZIF-8. As opposed to SAs prepared by the pyrolysis process only, SAs prepared by AMT are commonly anchored onto the surface of the supports, which is a simple and effective way to make full use of the source metal and prepare SACs with higher exposing active sites.Keywords:atom migration-trapping;single-atom catalysts;metal–organic frameworks
研究领域:
催化
·
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Jiashu Long,Xiaocan Zhang,Siqin Zeng,Tong Pei,Huixiao Ma,Xuesong Li,Xiaoyu Meng
Functionalized metal-organic frameworks (MOFs) are being extensively developed as viable fillers to enhance the proton conductivity of proton exchange membranes . Herein, an amino-pendant sulfonic acid bi-functionalized MOFs material (UNCS)-doped SPEEK membrane with low degree of sulfonation (DS) can improve the proton conductivity as well as maintain the membrane dimensional stability. UNCS can act as bridges of proton donors and acceptors to reduce the activation energy barrier and shorten the distance of long-range proton conduction. Among all as-prepared membranes, SPEEK/UNCS-3 exhibited the highest proton conductivity of 186.4 mS·cm −1 at 75 °C and 100% relative humidity (RH), which is much greater than that of pristine SPEEK and Nafion 117. Benefiting from the acid-base pair interaction between the amino groups of UNCS and the sulfonic acid groups of SPEEK, the dimensional stability and mechanical properties of the composite membranes were enhanced. More interestingly, STEM-HAADF and SAXS characterization consistently revealed that UNCS served as bridges among proton channels in the composite membranes for continuous proton transport.
研究领域:
材料科学
·
化学
·
电化学
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 43
·16981-16989
·
IF 3.069
Bingying Jia,Miaojiang Wu,Hua Zhang,Yi Zeng,Gongying Wang
Titanates are frequently used as precursors to prepare transesterification catalysts with TiIV species. Unfortunately, it is challenging to control the dispersity of TiIV active sites on supports. Herein, a series of TiIV species is anchored on abundant linker vacancy sites by introducing point and large scale defects in UiO-66(Zr/Ti) with hierarchical-pore structure. The catalyst functionalized by titanium(IV) oxide bis(2,4-pentanedionate) shows excellent catalytic performance in the transesterification of dimethyl carbonate with phenyl acetate. The catalysts are characterized by XRD, FT-IR, N2 adsorption–desorption, XPS, SEM and STEM-HAADF techniques. The results demonstrate that the delicate mesopores in the support can not only exhibit a large surface area for the distribution of the active sites, but also provide better mass transfer performance. Meanwhile, the introduction of octahedral TiIV ions raises the activity of the catalyst via more coordinatively unsaturated ZrIV sites. Furthermore, using titanium(IV) oxide bis(2,4-pentanedionate) as a Ti source can effectively prevent the condensation of tetrahedral TiIV species anchored on the hierarchical-pore UiO-66(Zr/Ti) support.
研究领域:
催化
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）