What Preferentially Determines theparaShape Selectivity: Diffusion of Molecules or External Surface Acidity

1999 ◽  
pp. 181-187 ◽  
Author(s):  
Miki Niwa ◽  
Takehisa Kunieda ◽  
Jong-Ho Kim
Keyword(s):  
External Surface ◽  
Surface Acidity

An investigation of the surface acidity of mesoporous Al-containing MCM-41 and of the external surface of ferrierite through pivalonitrile adsorption

1999 ◽  
Vol 182 (2) ◽  
pp. 225-235 ◽  
Author(s):  
Marcella Trombetta ◽  
Guido Busca ◽  
Maurizio Lenarda ◽  
Loretta Storaro ◽  
Massimo Pavan
Keyword(s):  
External Surface ◽  
Surface Acidity ◽  
Mcm 41

Mechanochemical Approach for Selective Deactivation of External Surface Acidity of ZSM-5 Zeolite Catalyst

2015 ◽  
Vol 7 (8) ◽  
pp. 4488-4493 ◽  
Author(s):  
Satoshi Inagaki ◽  
Koki Sato ◽  
Shunsuke Hayashi ◽  
Junichi Tatami ◽  
Yoshihiro Kubota ◽  
...  
Keyword(s):  
Zeolite Catalyst ◽  
External Surface ◽  
Surface Acidity

Study on the External Surface Acidity of MCM-22 Zeolite:  Theoretical Calculation and31P MAS NMR

2004 ◽  
Vol 108 (4) ◽  
pp. 1386-1391 ◽  
Author(s):  
Yan Wang ◽  
Jianqin Zhuang ◽  
Gang Yang ◽  
Danhong Zhou ◽  
Ding Ma ◽  
...  
Keyword(s):  
Theoretical Calculation ◽  
External Surface ◽  
Surface Acidity ◽  
Mas Nmr

Zeolite Beta: characterization and passivation of the external surface acidity

1997 ◽  
Vol 11 (5-6) ◽  
pp. 313-323 ◽  
Author(s):  
Paul J. Kunkeler ◽  
Dennis Moeskops ◽  
Herman van Bekkum
Keyword(s):  
External Surface ◽  
Surface Acidity ◽  
Zeolite Beta

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

High-resolution gold labeling

1993 ◽  
Vol 51 ◽  
pp. 330-331
Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya ◽  
Kyra Carbone ◽  
Martha Simon ◽  
Beth Lin ◽  
...  
Keyword(s):  
Dihydrofolate Reductase ◽  
Polypeptide Chain ◽  
External Surface ◽  
Gold Cluster ◽  
Macromolecular Complex ◽  
Gold Compound ◽  
Central Cavity ◽  
Chain Folding ◽  
E Coli ◽  
Chaperonin Groel

A recently developed 1.4 nm gold cluster has been found to be useful in labeling macromolecular sites to 1-3 nm resolution. The gold compound is organically derivatized to contain a monofunctional arm for covalent linking to biomolecules. This may be used to mark a specific site on a structure, or to first label a component and then reassemble a multicomponent macromolecular complex. Two examples are given here: the chaperonin groEL and ribosomes.Chaperonins are essential oligomeric complexes that mediate nascent polypeptide chain folding to produce active proteins. The E. coli chaperonin, groEL, has two stacked rings with a central hole ∽6 nm in diameter. The protein dihydrofolate reductase (DHFR) is a small protein that has been used in chain folding experiments, and serves as a model substrate for groEL. By labeling the DHFR with gold, its position with respect to the groEL complex can be followed. In particular, it was sought to determine if DHFR refolds on the external surface of the groEL complex, or whether it interacts in the central cavity.

Sign in / Sign up

Export Citation Format

Share Document