The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2)reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into ...The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2)reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N4-C)configuration to obtain Ni-X-N3-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N3-C(X:S,Se,and Te)SACs,Ni-Se-N3-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98%at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2)battery integrated with Ni-Se-N3-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm-2 and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N4-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N3-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of*COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.展开更多
Objective： The aim of the study was to explore the application of 64-slice spiral computed tomography perfusion imaging （CTPI） in evaluating angiogenesis in human osteosarcoma. Methods： Twenty-six patients （18 ma...Objective： The aim of the study was to explore the application of 64-slice spiral computed tomography perfusion imaging （CTPI） in evaluating angiogenesis in human osteosarcoma. Methods： Twenty-six patients （18 males and 8 females ranging from 9 to 56 years old, with an average of 19 years） with osteosarcoma underwent 64-slice spiral CTPI. We analyzed the correlations of CTPI parameters including blood flow （BF）, blood volume （BV）, time to peak （TTP）, and permeability surface （PS） with the expression of markers of angiogenesis. Statistical analysis was performed with paired-samples t test, and Pearson correlation analysis was employed to investigate the correlations of CTPI parameters with microvessel density （MVD）. Results： Mean BF, BV, TTP, and PS values of osteosarcoma group were （46.6 ± 25.1） mL/100 g/min, （61.8 ± 29.5） mL/100 g, （122.9 ± 26.2） seconds, and （44.5 ± 14.6） mL/100 g/min, respectively. Those in the normal muscle group were （5.2 ± 6.6） mL/100 g/min, （9.6 ± 7.3） mL/100 g, （115.5 ± 33.1） seconds and （17.0 ± 29.3） mL/100 g/min, respectively. Osteosarcoma group showed higher BF, BV and PS compared with the normal muscle group （P = 0.000, P = 0.000, and P = 0.000, respectively）. However, no significant difference was found in TTP between osteosarcoma tissue and normal adjacent muscle tissue （P = 0.273）. BF, BV, and PS were positively correlated with MVD （r = 0.83, P = 0.000; r = 0.87, P = 0.000; and r = 0.63, P = 0.001, respectively）. No correlation was found between TTP and MVD （r = –0.02, P = 0.93）. Conclusion： CTPI is useful for assessing tumor vascularity of osteosarcoma and CTPI parameters are positively correlated with MVD.展开更多
Tropos phosphine-oxazoline ligands have shown interesting coordination behavior and excellent chiral inducing ability in asymmetry catalysis.Here we present a convenient and economic route for the synthesis of this ty...Tropos phosphine-oxazoline ligands have shown interesting coordination behavior and excellent chiral inducing ability in asymmetry catalysis.Here we present a convenient and economic route for the synthesis of this type of ligands.According to this new route,the ligands with different electronic and steric properties have been prepared successfully.展开更多
The silver （Ag） nanowire arrays with regular and uniform size were successfully fabricated inside the nanochannels of anodic aluminum oxide （AAO） template by a simple paired cell method. X-ray diffi＇action （XRD...The silver （Ag） nanowire arrays with regular and uniform size were successfully fabricated inside the nanochannels of anodic aluminum oxide （AAO） template by a simple paired cell method. X-ray diffi＇action （XRD） and scanning elec- tron microscopy （SEM） results indicate that the as-synthesized samples are composed of face-centered cubic structure, and the average diameter is about 60-70 nm. Transmission electron microscopy （TEM） and the corresponding fast Fourier transformation （FFT） results show that Ag nanowires have a preferred single-crystal structure. Ultravio- let-visible （UV-vis） spectrum of Ag nanowire arrays exhibits UV emission band at 383 nm which can be attributed to the transverse dipole resonance ofAg nanowire arrays. A good surface-enhanced Raman scattering （SERS） spectrum is observed by excitation with a 514.5 nm laser, and the intensity of the SERS peak is about 23 times higher than that of the normal Raman peak measured from an empty AAO template. The high enhancement factor suggests that this method can be used to fabricate SERS sensor with high efficiency.展开更多
文摘The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2)reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N4-C)configuration to obtain Ni-X-N3-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N3-C(X:S,Se,and Te)SACs,Ni-Se-N3-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98%at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2)battery integrated with Ni-Se-N3-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm-2 and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N4-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N3-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of*COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.
基金Supported by a grant from the Medical Research Program Foundation for Talents of "Tenth five" of PLA (No. 04J002)
文摘Objective： The aim of the study was to explore the application of 64-slice spiral computed tomography perfusion imaging （CTPI） in evaluating angiogenesis in human osteosarcoma. Methods： Twenty-six patients （18 males and 8 females ranging from 9 to 56 years old, with an average of 19 years） with osteosarcoma underwent 64-slice spiral CTPI. We analyzed the correlations of CTPI parameters including blood flow （BF）, blood volume （BV）, time to peak （TTP）, and permeability surface （PS） with the expression of markers of angiogenesis. Statistical analysis was performed with paired-samples t test, and Pearson correlation analysis was employed to investigate the correlations of CTPI parameters with microvessel density （MVD）. Results： Mean BF, BV, TTP, and PS values of osteosarcoma group were （46.6 ± 25.1） mL/100 g/min, （61.8 ± 29.5） mL/100 g, （122.9 ± 26.2） seconds, and （44.5 ± 14.6） mL/100 g/min, respectively. Those in the normal muscle group were （5.2 ± 6.6） mL/100 g/min, （9.6 ± 7.3） mL/100 g, （115.5 ± 33.1） seconds and （17.0 ± 29.3） mL/100 g/min, respectively. Osteosarcoma group showed higher BF, BV and PS compared with the normal muscle group （P = 0.000, P = 0.000, and P = 0.000, respectively）. However, no significant difference was found in TTP between osteosarcoma tissue and normal adjacent muscle tissue （P = 0.273）. BF, BV, and PS were positively correlated with MVD （r = 0.83, P = 0.000; r = 0.87, P = 0.000; and r = 0.63, P = 0.001, respectively）. No correlation was found between TTP and MVD （r = –0.02, P = 0.93）. Conclusion： CTPI is useful for assessing tumor vascularity of osteosarcoma and CTPI parameters are positively correlated with MVD.
基金supported by the National Natural Science Foundation of China (20772081)Science and Technology Commission of Shanghai Municipality (09431902500)
文摘Tropos phosphine-oxazoline ligands have shown interesting coordination behavior and excellent chiral inducing ability in asymmetry catalysis.Here we present a convenient and economic route for the synthesis of this type of ligands.According to this new route,the ligands with different electronic and steric properties have been prepared successfully.
基金supported by the High Level Talents Introduction Project of Xinjiang Uygur Autonomous Region(No.2013)
文摘The silver （Ag） nanowire arrays with regular and uniform size were successfully fabricated inside the nanochannels of anodic aluminum oxide （AAO） template by a simple paired cell method. X-ray diffi＇action （XRD） and scanning elec- tron microscopy （SEM） results indicate that the as-synthesized samples are composed of face-centered cubic structure, and the average diameter is about 60-70 nm. Transmission electron microscopy （TEM） and the corresponding fast Fourier transformation （FFT） results show that Ag nanowires have a preferred single-crystal structure. Ultravio- let-visible （UV-vis） spectrum of Ag nanowire arrays exhibits UV emission band at 383 nm which can be attributed to the transverse dipole resonance ofAg nanowire arrays. A good surface-enhanced Raman scattering （SERS） spectrum is observed by excitation with a 514.5 nm laser, and the intensity of the SERS peak is about 23 times higher than that of the normal Raman peak measured from an empty AAO template. The high enhancement factor suggests that this method can be used to fabricate SERS sensor with high efficiency.
