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Niu HJ, Huang C, Sun T, Fang Z, Ke X, Zhang R, Ran N, Wu J, Liu J, Zhou W. Enhancing Ni/Co Activity by Neighboring Pt Atoms in NiCoP/MXene Electrocatalyst for Alkaline Hydrogen Evolution. Angew Chem Int Ed Engl 2024:e202401819. [PMID: 38409658 DOI: 10.1002/anie.202401819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 02/28/2024]
Abstract
Density functional theory (DFT) calculations demonstrate neighboring Pt atoms can enhance the metal activity of NiCoP for hydrogen evolution reaction (HER). However, it remains a great challenge to link Pt and NiCoP. Herein, we introduced curvature of bowl-like structure to construct Pt/NiCoP interface by adding a minimal 1 ‰-molar-ratio Pt. The as-prepared sample only requires an overpotential of 26.5 and 181.6 mV to accordingly achieve the current density of 10 and 500 mA cm-2 in 1 M KOH. The water dissociation energy barrier (Ea) has a ~43 % decrease compared with NiCoP counterpart. It also shows an ultrahigh stability with a small degradation rate of 10.6 μV h-1 at harsh conditions (500 mA cm-2 and 50 °C) after 3000 hrs. X-ray photoelectron spectroscopy (XPS), soft X-ray absorption spectroscopy (sXAS), and X-ray absorption fine structure (XAFS) verify the interface electron transfer lowers the valence state of Co/Ni and activates them. DFT calculations also confirm the catalytic transition step of NiCoP can change from Heyrovsky (2.71 eV) to Tafel step (0.51 eV) in the neighborhood of Pt, in accord with the result of the improved Hads at the interface disclosed by in situ electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) tests.
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Affiliation(s)
- Hua-Jie Niu
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100191, China
| | - Chuanxue Huang
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100191, China
| | - Tong Sun
- College of Chemistry and Chemical Engineering, Instrumental Analysis Center of Qingdao University, Qingdao University, Qingdao, 266071, China
| | - Zhen Fang
- State Key Laboratory of Metal Matrix Composites, Center of Hydrogen Science, Zhangjiang Institute for Advanced Study, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiaoxing Ke
- Beijing Key Laboratory of Microstructure and Properties of Solids, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100124, China
| | - Ruimin Zhang
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100191, China
| | - Nian Ran
- State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Jianbo Wu
- State Key Laboratory of Metal Matrix Composites, Center of Hydrogen Science, Zhangjiang Institute for Advanced Study, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jianjun Liu
- State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Wei Zhou
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 100191, China
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Niu HJ, Yan Y, Jiang S, Liu T, Sun T, Zhou W, Guo L, Li J. Interfaces Decrease the Alkaline Hydrogen-Evolution Kinetics Energy Barrier on NiCoP/Ti 3C 2T x MXene. ACS Nano 2022; 16:11049-11058. [PMID: 35796532 DOI: 10.1021/acsnano.2c03711] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Heterointerfaces can adjust the adsorption energy with intermediates in the transition state for a much decreased kinetics energy barrier (Ea). One typical transition metal phosphide, NiCoP grains (∼5 nm in size), was anchored on a Ti3C2Tx MXene monolayer (∼1 nm in thickness) to boost the kinetics toward alkaline hydrogen evolution reaction (HER). General electrochemical experiments at different temperatures give a small Ea of 31.4 kJ mol-1, showing a 22.1% decrease compared to its counterpart NiCoP nanoparticles (40.3 kJ mol-1). Impressively, the overpotential of NiCoP@MXene dramatically decreases from 71 mV to 4 mV at 10 mA cm-2 when the temperature increases from 25 °C to 65 °C. On a single NiCoP@MXene sheet, scanning electrochemical microscopy (SECM) tests also give a very close value of Ea = 31.9 kJ mol-1, with a relative error of ∼1.6%. Density functional theory (DFT) calculations confirm the interface between NiCoP and MXene can effectively decrease the energy barrier of water dissociation by 16.0%. The three kinds of studies on macro, micro/nano, and atomic scales disclose the interfaces can reduce the kinetics energy barrier about 16.0-22.1%. Besides, the photothermal effect of MXenes can easily raise the catalyst temperature under vis-NIR light, which has been applied in practical scenarios under sunlight for energy savings.
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Affiliation(s)
- Hua-Jie Niu
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Yu Yan
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - SiSi Jiang
- College of Chemistry and Chemical Engineering, Instrumental Analysis Center of Qingdao University, Qingdao University, Qingdao 266071, China
| | - Tong Liu
- School of Transportation Science and Engineering, Beihang University, Beijing 100191, China
| | - Tong Sun
- College of Chemistry and Chemical Engineering, Instrumental Analysis Center of Qingdao University, Qingdao University, Qingdao 266071, China
| | - Wei Zhou
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Lin Guo
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Jinghong Li
- Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Tsinghua University, Beijing 100084, China
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Chen HY, Niu HJ, Han Z, Feng JJ, Huang H, Wang AJ. Simple fabrication of trimetallic platinum-nickel-cobalt hollow alloyed 3D multipods for highly boosted hydrogen evolution reaction. J Colloid Interface Sci 2020; 570:205-211. [DOI: 10.1016/j.jcis.2020.02.090] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/18/2020] [Accepted: 02/22/2020] [Indexed: 10/24/2022]
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Wen GL, Niu HJ, Feng JJ, Luo X, Weng X, Wang AJ. Well-dispersed Co3Fe7 alloy nanoparticles wrapped in N-doped defect-rich carbon nanosheets as a highly efficient and methanol-resistant catalyst for oxygen-reduction reaction. J Colloid Interface Sci 2020; 569:277-285. [DOI: 10.1016/j.jcis.2020.02.089] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 12/16/2022]
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Chen HY, Niu HJ, Ma X, Feng JJ, Weng X, Huang H, Wang AJ. Flower-like platinum-cobalt-ruthenium alloy nanoassemblies as robust and highly efficient electrocatalyst for hydrogen evolution reaction. J Colloid Interface Sci 2020; 561:372-378. [DOI: 10.1016/j.jcis.2019.10.122] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 11/16/2022]
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Duan JJ, Zheng XX, Niu HJ, Feng JJ, Zhang QL, Huang H, Wang AJ. Porous dendritic PtRuPd nanospheres with enhanced catalytic activity and durability for ethylene glycol oxidation and oxygen reduction reactions. J Colloid Interface Sci 2020; 560:467-474. [DOI: 10.1016/j.jcis.2019.10.082] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/19/2019] [Accepted: 10/21/2019] [Indexed: 11/29/2022]
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Niu HJ, Zhang L, Feng JJ, Zhang QL, Huang H, Wang AJ. Graphene-encapsulated cobalt nanoparticles embedded in porous nitrogen-doped graphitic carbon nanosheets as efficient electrocatalysts for oxygen reduction reaction. J Colloid Interface Sci 2019; 552:744-751. [DOI: 10.1016/j.jcis.2019.05.099] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 10/26/2022]
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Wen GL, Niu HJ, Wang AJ, Yin ZZ, Zhang QL, Feng JJ. Graphene wrapped Fe 7C 3 nanoparticles supported on N-doped graphene nanosheets for efficient and highly methanol-tolerant oxygen reduction reaction. J Colloid Interface Sci 2019; 556:352-359. [PMID: 31465966 DOI: 10.1016/j.jcis.2019.08.064] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 01/15/2023]
Abstract
Green and efficient non-precious metal electrocatalysts for oxygen reduction reaction (ORR) are prepared to meet the increasing demand for clean, secure and sustainable energy. Herein, we report a novel and environmentally friendly strategy for synthesis of graphene-wrapped iron carbide (Fe7C3) nanoparticles supported on hierarchical fibrous N-doped graphene with open-mesoporous structures (Fe7C3/NG) by simply annealing the mixture of melamine, iron (II) phthalocyanine (FePc) and Fe2O3. The effects of the pyrolysis temperature and the molar ratio of FePc to melamine were critically examined in the controls. Remarkably, the Fe7C3/NG obtained at 800 °C (i.e. Fe7C3/NG-800) manifested the forward shifts in the onset potential (0.98 V) and half-wave potential (0.85 V) with respective to commercial Pt/C (50 wt%) in 0.1 M KOH, coupled with the great enhancement in the durability (still remained 92.11% of its initial current density even after 40,000 s) and strong methanol tolerance. This research presents a promising strategy for developing Pt-free non-precious efficient ORR electrocatalysts in fuel cells.
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Affiliation(s)
- Gui-Lin Wen
- College of Geography and Environmental Sciences, College of Chemistry and Life Sciences, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China
| | - Hua-Jie Niu
- College of Geography and Environmental Sciences, College of Chemistry and Life Sciences, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China
| | - Ai-Jun Wang
- College of Geography and Environmental Sciences, College of Chemistry and Life Sciences, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China
| | - Zheng-Zhi Yin
- College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, Zhejiang, China.
| | - Qian-Li Zhang
- School of Chemistry and Biological Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jiu-Ju Feng
- College of Geography and Environmental Sciences, College of Chemistry and Life Sciences, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, China.
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Niu HJ, Chen HY, Wen GL, Feng JJ, Zhang QL, Wang AJ. One-pot solvothermal synthesis of three-dimensional hollow PtCu alloyed dodecahedron nanoframes with excellent electrocatalytic performances for hydrogen evolution and oxygen reduction. J Colloid Interface Sci 2019; 539:525-532. [DOI: 10.1016/j.jcis.2018.12.066] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/13/2018] [Accepted: 12/17/2018] [Indexed: 11/24/2022]
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Wang NN, Yan X, Gao XN, Niu HJ, Kang ZS, Huang LL. Purification and characterization of a potential antifungal protein from Bacillus subtilis E1R-J against Valsa mali. World J Microbiol Biotechnol 2016; 32:63. [PMID: 26925625 DOI: 10.1007/s11274-016-2024-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/03/2016] [Indexed: 01/29/2023]
Abstract
In order to identify the antagonistic substances produced by Bacillus subtilis E1R-J as candidate of biocontrol agents for controlling Apple Valsa Canker, hydrochloric acid precipitation, reverse phase chromatography, gel filtration, and ion exchange chromatography were used. The purified fraction EP-2 showed a single band in native-polyacrylamide gel electrophoresis (native-PAGE) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Fraction EP-2 was eluted from native-PAGE and showed a clear inhibition zone against V. mali 03-8. These results prove that EP-2 is one of the most important antifungal substances produced by B. subtilis E1R-J in fermentation broth. SDS-PAGE and Nano-LC-ESI-MS/MS analysis results demonstrated that EP-2 was likely an antifungal peptide (trA0A086WXP9), with a relative molecular mass of 12.44 kDa and isoelectric point of 9.94. The examination of antagonistic mechanism under SEM and TEM showed that EP-2 appeared to inhibit Valsa mali 03-8 by causing hyphal swelling, distortion, abnormality and protoplasts extravasation. Inhibition spectrum results showed that antifungal protein EP-2 had significantly inhibition on sixteen kinds of plant pathogenic fungi. The stability test results showed that protein EP-2 was stable with antifungal activity at temperatures as high as 100 °C for 30 min and in pH values ranging from 1.0 to 8.0, or incubated with each 5 mM Cu(2+), Zn(2+), Mg(2+), or K(+). However, the antifungal activity was negatively affected by Proteinase K treatment.
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Affiliation(s)
- N N Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - X Yan
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - X N Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - H J Niu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - Z S Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - L L Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
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Sun LW, Blottner D, Luan HQ, Salanova M, Wang C, Niu HJ, Felsenberg D, Fan YB. Bone and muscle structure and quality preserved by active versus passive muscle exercise on a new stepper device in 21 days tail-suspended rats. J Musculoskelet Neuronal Interact 2013; 13:166-177. [PMID: 23728103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Human performance in microgravity is characterized by reversed skeletal muscle actions in terms of active vs. passive mode contractions of agonist/antagonist groups that may challenge principal biodynamics (biomechanical forces translated from muscle to bone) of the skeletal muscle-bone unit. We investigated active vs. passive muscle motions of the unloaded hindlimb skeletal muscle-bone unit in the 21 days tail-suspended (TS) rat using a newly designed stepper exercise device. The regimen included both active mode motions (TSA) and passive mode motions (TSP). A TS-only group and a normal cage group (CON) served as positive or negative controls. The muscle and bone decrements observed in TS-only group were not seen in the other groups except TSP. Active mode motions supported femur and tibia bone quality (5% BMD, 10% microtrabecular BV/TV, Tb.Th., Tb.N. parameters), whole soleus muscle/myofiber size and type II distribution, 20% increased sarcolemma NOS1 immunosignals vs. CON, with 25% more hybrid fiber formation (remodeling sign) for all TS groups. We propose a new custom-made stepper device to be used in the TS rat model that allows for detailed investigations of the unique biodynamic properties of the muscle-bone unit during resistive-load exercise countermeasure trials on the ground or in microgravity.
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Affiliation(s)
- L W Sun
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
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Wang Q, Zheng YP, Niu HJ. Changes in triphasic mechanical properties of proteoglycan-depleted articular cartilage extracted from osmotic swelling behavior monitored using high-frequency ultrasound. Mol Cell Biomech 2010; 7:45-58. [PMID: 20806723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This study aims to obtain osmosis-induced swelling strains of normal and proteoglycan (PG) depleted articular cartilage using an ultrasound system and to investigate the changes in its mechanical properties due to the PG depletion using a layered triphasic model. The swelling strains of 20 cylindrical cartilage-bone samples collected from different bovine patellae were induced by decreasing the concentration of bath saline and monitored by the ultrasound system. The samples were subsequently digested by a trypsin solution for approximately 20 min to deplete proteoglycans, and the swelling behaviors of the digested samples were measured again. The bi-layered triphasic model proposed in our previous study (Wang et al., J Biomech Eng-Trans ASME 2007; 129: 413-422) was used to predict the layered aggregate modulus Ha from the data of depth-dependent swelling strain, fixed charge density and water content. It was found that the region near the bone, for the normal specimens, had a significantly higher aggregate modulus (Ha1 = 20.6 +/- 18.2 MPa) in comparison with the middle zone and the surface layer (Ha2 = 7.8 +/- 14.5 MPa and Ha3 = 3.6 +/- 3.2 MPa, respectively) (p < 0.001). The normalized thickness of the deep layer h1 was 0.68 +/- 0.20. After the trypsin digestion, the parametric values decreased to Ha1 = 13.6 +/- 9.6 MPa, Ha2 = 6.7 +/- 11.5 MPa, Ha3 = 2.7 +/- 3.2 MPa, and h1 = 0.57 +/- 0.28. Other models were also used to analyze data and the results were compared. This study showed that high-frequency ultrasound measurement combined with the triphasic modeling was capable of nondestructively quantifying the alterations in the layered mechanical properties of the proteoglycan-depleted articular cartilage.
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Affiliation(s)
- Q Wang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
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Jiang Y, Wong JH, Pi ZF, Ng TB, Wang CR, Hou J, Chen RR, Niu HJ, Liu F. Stimulatory effect of components of rose flowers on catalytic activity and mRNA expression of superoxide dismutase and catalase in erythrocytes. Environ Toxicol Pharmacol 2009; 27:396-401. [PMID: 21783970 DOI: 10.1016/j.etap.2009.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 12/23/2008] [Accepted: 01/18/2009] [Indexed: 05/31/2023]
Abstract
In the present study, two antioxidant components (polysaccharopeptide complex P(1-a) and condensed tannin P(1-b)) from rose (Rosa rugosa) flowers were each incubated with mouse erythrocytes to investigate their effect on erythrocyte superoxide dismutase (SOD), and catalase (CAT) activities. It was found that the activities of Cu, Zn-SOD and CAT were markedly increased after incubation for 3h with rose flower fractions at the concentration of 500μg/ml. Similar changes were also observed in the erythrocyte gene expression of SOD and CAT. These results show that P(1-a) and P(1-b) are effective antioxidants that increase the activity and the gene expression of SOD and CAT in mouse erythrocytes.
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Affiliation(s)
- Y Jiang
- The Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
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Wang P, Bleloch AL, Yan L, Niu HJ, Chalker PR, Rosseinsky MJ, Goodhew PJ. Aberration corrected STEM of defects in epitaxial n=4 Ruddlesden-Popper phase Can+1MnnO3n+1. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/126/1/012050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wang Q, Zheng YP, Niu HJ, Mak AFT. Extraction of mechanical properties of articular cartilage from osmotic swelling behavior monitored using high frequency ultrasound. J Biomech Eng 2007; 129:413-22. [PMID: 17536909 DOI: 10.1115/1.2720919] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Articular cartilage is a biological weight-bearing tissue covering the bony ends of articulating joints. Negatively charged proteoglycan (PG) in articular cartilage is one of the main factors that govern its compressive mechanical behavior and swelling phenomenon. PG is nonuniformly distributed throughout the depth direction, and its amount or distribution may change in the degenerated articular cartilage such as osteoarthritis. In this paper, we used a 50 MHz ultrasound system to study the depth-dependent strain of articular cartilage under the osmotic loading induced by the decrease of the bathing saline concentration. The swelling-induced strains under the osmotic loading were used to determine the layered material properties of articular cartilage based on a triphasic model of the free-swelling. Fourteen cylindrical cartilage-bone samples prepared from fresh normal bovine patellae were tested in situ in this study. A layered triphasic model was proposed to describe the depth distribution of the swelling strain for the cartilage and to determine its aggregate modulus H(a) at two different layers, within which H(a) was assumed to be linearly dependent on the depth. The results showed that H(a) was 3.0+/-3.2, 7.0+/-7.4, 24.5+/-11.1 MPa at the cartilage surface, layer interface, and deep region, respectively. They are significantly different (p<0.01). The layer interface located at 70%+/-20% of the overall thickness from the uncalcified-calcified cartilage interface. Parametric analysis demonstrated that the depth-dependent distribution of the water fraction had a significant effect on the modeling results but not the fixed charge density. This study showed that high-frequency ultrasound measurement together with triphasic modeling is practical for quantifying the layered mechanical properties of articular cartilage nondestructively and has the potential for providing useful information for the detection of the early signs of osteoarthritis.
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Affiliation(s)
- Q Wang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, China
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Zheng YP, Niu HJ, Arthur Mak FT, Huang YP. Ultrasonic measurement of depth-dependent transient behaviors of articular cartilage under compression. J Biomech 2005; 38:1830-7. [PMID: 16023470 DOI: 10.1016/j.jbiomech.2004.08.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2004] [Indexed: 11/30/2022]
Abstract
We previously reported an ultrasound method for measuring the depth-dependent equilibrium mechanical properties of articular cartilage using quasi-static compression. The objective of this paper was to introduce our recent development for nondestructively measuring the transient depth-dependent strains of full-thickness articular cartilage specimens prepared from bovine patellae. A 50 MHz focused ultrasound transducer was used to collect ultrasound echoes from articular cartilage specimens (n=8) and sponge phantoms with open pores (n=10) during tests of compression and subsequent stress-relaxation. The transient displacements of the tissues at different depths along the compression direction were calculated from the ultrasound echoes using a cross-correlation tracking technique. An LVDT sensor and a load cell were used to measure the overall deformation of the tissue and the applied force, respectively. Results showed that the tissues inside the cartilage layer continued to move during the stress-relaxation phase after the compression was completed. In the equilibrium state, the displacements of the cartilage tissues at the depths of 1/4, 1/2, and 3/4 of the full-thickness reduced by 51%+/-22%, 54%+/-17%, and 50+/-17%, respectively, in comparison with its peak value. However, no similar phenomenon was observed in the sponge phantoms. Our preliminary results demonstrated that this ultrasound method may provide a potential tool for the nondestructive measurement of the transient depth-dependent processes involved in biological and bioengineered soft tissues as well as soft biomaterials under dynamic loading.
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Affiliation(s)
- Y P Zheng
- Jockey Club Rehabilitation Engineering Center, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
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Niu HJ, Wan MX, Wang SP, Liu HJ. Enhancement of electrolarynx speech using adaptive noise cancelling based on independent component analysis. Med Biol Eng Comput 2004; 41:670-8. [PMID: 14686593 DOI: 10.1007/bf02349975] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electrolarynx provides a valuable means of verbal communication for people who cannot use their natural voice-production mechanism, but technology has changed very little since it was introduced in the 1950s. The presence of background noise degrades the resulting speech. In this study background noise was reduced by a new method, independent component analysis-based adaptive noise cancelling, which can remove noise components of the primary input signal based on statistical independence, by incorporating both second-order and higher-order statistics. The method shows better performance than the conventional least mean square algorithm. Acoustic analysis of the denoised electrolarynx speech revealed a significant reduction in the amount of background noise. Results from the perceptual evaluations indicated that the new filtering technique produced a noticeable improvement in the acceptability of the electrolarynx speech in a quiet environment (from 1.75 to 2.49, arbitrary units) or a noisy environment (from 0.59 to 1.82). In general, there was no significant improvement or degradation in intelligibility in the quiet environment (from 52.7 to 53.3). However, the processing did improve the intelligibility in a babble-noise environment (from 24.9 to 40.6). The improvement in acceptability and intelligibility may increase the communication ability of the user in daily situations.
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Affiliation(s)
- H J Niu
- Department of Biomedical Engineering, School of Life Science & Technology, Xi'an Jiaotong University, Xi'an, China
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Niu HJ, Hampshire DP. Disordered nanocrystalline superconducting PbMo6S8 with a very large upper critical field. Phys Rev Lett 2003; 91:027002. [PMID: 12906503 DOI: 10.1103/physrevlett.91.027002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2002] [Indexed: 05/24/2023]
Abstract
Large increases in the upper critical field B(C2)(0) are reported in bulk superconductors that demonstrate another novel property for nanocrystalline materials. Disordered nanocrystalline PbMo6S8 superconductors were fabricated by mechanical milling and hot isostatic pressing. Conventional PbMo6S8 has B(C2)(0) approximately 50 T. The nanocrystalline materials have higher resistivity (rho(N)) and B(C2)(0) approximately 100 T. The disorder produced in these nanocrystalline materials is significantly different from that produced by doping because it increases rho(N) and, hence, B(C2)(0) without significantly reducing the electronic density of states or superconducting transition temperature (T(C)). Furthermore, the disorder reduces the electron mean-free path to approximately 1 nm which is more than an order of magnitude smaller than the grain size and necessary to achieve the unprecedented increase in B(C2)(0).
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Affiliation(s)
- H J Niu
- Superconductivity Group, Department of Physics, University of Durham, Durham DH1 3LE, United Kingdom
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