Direct imaging of heteroatom dopants in catalytic carbon nano-onions

Nanoscale ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 6144-6152
Author(s):  
Melonie P. Thomas ◽  
Namal Wanninayake ◽  
Manisha De Alwis Goonatilleke ◽  
Doo Young Kim ◽  
Beth S. Guiton
Keyword(s):  
Catalytic Activity ◽  
Dopant Atom ◽  
Direct Visualization ◽  
Structure Property ◽  
Direct Imaging ◽  
Atom Configuration

Direct visualization of dopant atom configuration in carbon nano-onions provides structure–property link to catalytic activity.

The effect of different metal oxides on the catalytic activity of a Co3O4 catalyst for toluene combustion: importance of the structure–property relationship and surface active species

2019 ◽  
Vol 43 (27) ◽  
pp. 10868-10877 ◽  
Author(s):  
Xuejun Zhang ◽  
Min Zhao ◽  
Zhongxian Song ◽  
Heng Zhao ◽  
Wei Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Oxides ◽  
Catalytic Oxidation ◽  
Active Species ◽  
Active Oxygen ◽  
Redox Cycle ◽  
Structure Property ◽  
Property Relationship ◽  
Structure Property Relationship ◽  
Surface Active

The Co–La catalyst was used to the catalytic oxidation of toluene. The LaCoO3 perovskite was detected. The abundance of Co3+ and active oxygen contributed synergistically to the redox cycle reaction, which could improve the catalytic activity.

Structure–property relationships in series of natural and synthetic inhibitors of catalytic activity of 15-lipoxygenase

2011 ◽  
Vol 45 (9) ◽  
pp. 539-546 ◽  
Author(s):  
V. R. Khairullina ◽  
A. Ya. Gerchikov ◽  
I. A. Taipov ◽  
H. Boegel ◽  
F. S. Zarudii
Keyword(s):  
Catalytic Activity ◽  
Structure Property ◽  
Structure Property Relationships ◽  
In Series ◽  
Natural And Synthetic

Preliminary investigation on the catalytic mechanism of TiF3 additive in MgH2–TiF3 H-storage system

2007 ◽  
Vol 22 (7) ◽  
pp. 1779-1786 ◽  
Author(s):  
Lai-Peng Ma ◽  
Ping Wang ◽  
Xiang-Dong Kang ◽  
Hui-Ming Cheng
Keyword(s):  
Catalytic Activity ◽  
Catalytic Mechanism ◽  
Metastable Phase ◽  
Storage System ◽  
Preliminary Investigation ◽  
Comparative Investigation ◽  
Active Species ◽  
Structure Property ◽  
Catalytically Active ◽  
Combined Structure

A combined structure/property investigation is performed to understand the catalytic effect of TiF3 additive on the absorption/desorption reactions of MgH2. It was found that both TiH2 and MgF2 phases identified by x-ray diffraction cannot explain the observed kinetic enhancement in the MgH2–TiF3 system, whether they are incorporated in a direct or an in situ manner. In combination with the comparative investigation on the catalytic activity of TiF3 and its analog TiCl3, as well as the samples milled under inert and reactive atmospheres, we propose that the catalytically active species is a multicomponent metastable phase composed of host Mg, transition metal Ti, and F anion, the catalytic activity of which is dependent on its interaction with the surrounding chemical environment.

Template Synthesis and Electrocatalytic Properties of Palladium Hollow Spheres

2013 ◽  
Vol 709 ◽  
pp. 11-14
Author(s):  
Hai Long Lu ◽  
Wan Neng Ye ◽  
Pei Zhi Guo ◽  
Qin Chao Wang ◽  
Chao Jing Lu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Solvothermal Method ◽  
Hollow Spheres ◽  
Cobalt Nanoparticles ◽  
Saed Pattern ◽  
High Catalytic Activity ◽  
Structure Property ◽  
Structure Property Relationship ◽  
Relationship Of

Palladium hollow spheres were synthesized at room temperature using cobalt nanoparticles (NPs) as sacrificing templates. Cobalt NPs can be prepared simply by solvothermal method. The hollow nature of sample Pd were observed from the TEM image and the SAED pattern indicates the polycrystalline nature of the sample. It was found that Pd hollow spheres showed high catalytic activity towards the electrooxidation of alcohols, especially ethanol with the current density up to 2047 mA•mg-1. The formation mechanism and the structure-property relationship of Pd hollow spheres were discussed based on the experimental results.

Direct Imaging of Atom Configuration Projected onto the Basel Place in Molybdenite Crystal

Microscopy ◽  
1979 ◽  
Vol 28 (3) ◽  
pp. 182-184
Author(s):  
Shigemi FURUNO ◽  
Kazuhiko IZUI ◽  
Hitoshi OTSU
Keyword(s):  
Direct Imaging ◽  
Atom Configuration

Visualization of stable ferritin complexes with palladium, rhodium and iridium nanoparticles detected by their catalytic activity in native polyacrylamide gels

2017 ◽  
Vol 46 (40) ◽  
pp. 13690-13694 ◽  
Author(s):  
Vladimir Pekarik ◽  
Marie Peskova ◽  
Roman Guran ◽  
Jiri Novacek ◽  
Zbynek Heger ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Nanoparticles ◽  
Protein Complexes ◽  
Direct Visualization ◽  
Polyacrylamide Gels ◽  
Iridium Nanoparticles

Direct visualization of proteins and the catalytic activity of metal nanoparticles from metal–protein complexes in native polyacrylamide gels.

A luminescent lanthanide approach towards direct visualization of primary cilia in living cells

2017 ◽  
Vol 53 (52) ◽  
pp. 7084-7087 ◽  
Author(s):  
Hongguang Li ◽  
Rongfeng Lan ◽  
Chi-Fai Chan ◽  
Guochen Bao ◽  
Chen Xie ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Living Cells ◽  
Direct Visualization ◽  
Direct Imaging ◽  
Europium Luminescence ◽  
Imaging Tool

A simple and direct imaging tool (HGEu001) for primary cilia based on long-lived europium luminescence is firstly presented.

scholarly journals Direct Visualization of Platelet Integrins Using ANTI-Transmembrane Domain Peptides Containing a BLUE Fluorescent Amino Acid

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2344-2344
Author(s):  
Karen Pei Yi Fong ◽  
Ismail A. Ahmed ◽  
Marco Mravic ◽  
Hyunil Jo ◽  
William F. DeGrado ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Membranes ◽  
Platelet Adhesion ◽  
Unnatural Amino Acid ◽  
Wide Field ◽  
Direct Visualization ◽  
Cell Surfaces ◽  
Direct Imaging ◽  
Alexa Fluor ◽  
Activated State

Antibodies containing a fluorescent label or recombinant proteins containing a fluorescent reporter are commonly used to visualize proteins in situ. However, antibodies and bulky reporters can perturb protein structure and function. To overcome this problem, we have designed a minimally perturbing blue fluorescent unnatural amino acid that enables the direct imaging of intrinsically-fluorescent proteins with their interaction partners. Specifically, we used a nitrile-derivatized tryptophan, 4-cyanotryptophan (4CNTrp), which differs by only two atoms from native tryptophan. 4CNTrp has unique photophysical properties in the visible blue region: an absorption maximum at ~325 nm, an emission maximum at ~420 nm, a large fluorescence quantum yield (>0.8 in aqueous solution), a long fluorescence lifetime (ca. 13 ns), and good photostability (Hilaire et al. PNAS 2017; 114: 6005-09). Based on these properties, 4CNTrp-labeling was recently used to visualize the binding of a model peptide pHLIP (pH-(Low) Insertion Peptide) to cell membranes via wide-field fluorescence microscopy. 4CNTrp is also a viable FRET donor for acceptor pairs in the green visible region. 4CNTrp can be prepared by a simple, high-yielding cost-effective synthetic route and because it does not inhibit bacterial growth, it may be practical for cellular applications (Zhang et al. Chem. Comm. 2019; 55: 5095-98). Here, we used 4CNTrp-labeled peptides to directly image integrins on cell surfaces. Previously, we described the synthesis of peptides, called CHAMP peptides for Computed Helical Anti-Membrane Protein, that target the transmembrane (TM) domains of integrins in a sequence-specific manner (Yin et al. Science 2007; 315: 1817-22). Thus, the CHAMP peptides anti-αIIb and anti-αv specifically bind to the TM domains of αIIb and αv in platelet membranes, causing separation of the αIIbβ3 and αvβ3 TM domains and αIIbβ3 and αvβ3 activation. Anti-αIIb also caused αIIbβ3 clustering that was visualized using the β3-specific monoclonal antibody SSA6 labeled with Alexa Fluor 488 but only after the platelets were fixed with paraformaldehyde to prevent antibody-induced clustering. To enable the direct visualization of αIIβ3, αvβ3, and α2β1 on cell surfaces, we used solid-phase peptide synthesis to generate CHAMP peptides labeled with 4CNTrp at their N-termini (CN-αIIb, CN-αv, CN-β1). We found that 4CNTrp labeling did not perturb the ability of the CHAMP peptides to bind to integrins and to cause specific integrin activation. Thus, CN-αIIb caused αIIbβ3-dependent platelet aggregation, CN-αv caused the αvβ3-dependent platelet adhesion to osteopontin, and CN-α1 caused α2β1-mediated platelet adhesion to collagen. We then used high resolution wide-field deconvolution microscopy to image 4CNTrp-containing integrins on the surface of platelets, HEL cells, and transfected CHO cells. Compared to 4CNTrp-containing random peptides that uniformly decorate cell surfaces, the CN-labeled CHAMP peptides were present as a limited number of discrete foci on the cell surface. To confirm that these foci represented CN-peptide containing integrins, we co-stained the cells with Alexa Fluor 488-labeled integrin-specific monoclonal antibodies and found that CN-peptide and antibody fluorescence coincided. Thus, these studies demonstrate the specific and direct imaging of integrins embedded in cell membranes in their activated state using 4CNTrp-labeled anti-integrin TM peptides. Because 4CNTrp can readily be incorporated into proteins and peptides with little if any structural perturbation, 4CNTrp-labeling provides a facile way to directly monitor protein behavior and protein-protein interactions in cellular environments. Disclosures No relevant conflicts of interest to declare.

Direct visualization of phase-separated domains in lipid membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 290-291
Author(s):  
S. W. Hui ◽  
T. P. Stewart
Keyword(s):  
Lipid Membranes ◽  
Structural Information ◽  
Freeze Fracture ◽  
Biological Molecules ◽  
Vacuum Drying ◽  
Direct Visualization ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Hydrocarbon Chains

Direct electron microscopic study of biological molecules has been hampered by such factors as radiation damage, lack of contrast and vacuum drying. In certain cases, however, the difficulties may be overcome by using redundent structural information from repeating units and by various specimen preservation methods. With bilayers of phospholipids in which both the solid and fluid phases co-exist, the ordering of the hydrocarbon chains may be utilized to form diffraction contrast images. Domains of different molecular packings may be recgnizable by placing properly chosen filters in the diffraction plane. These domains would correspond to those observed by freeze fracture, if certain distinctive undulating patterns are associated with certain molecular packing, as suggested by X-ray diffraction studies. By using an environmental stage, we were able to directly observe these domains in bilayers of mixed phospholipids at various temperatures at which their phases change from misible to inmissible states.

High resolution electron microscopy of lanthanum phosphate crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 274-275
Author(s):  
J. C. Wheatley ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
High Resolution ◽  
Petroleum Industry ◽  
High Resolution Electron Microscopy ◽  
Lanthanum Phosphate ◽  
Good Catalyst ◽  
Resolution Electron ◽  
Good Catalytic Activity ◽  
Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

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