SYNTHESIS FOR NANOFLOWER AND ROD OF ZnO BY A SURFACTANT FREE AND LOW TEMPERATURE METHOD

2010 ◽  
Vol 17 (02) ◽  
pp. 173-176 ◽  
Author(s):  
BYUNG SUN HAN ◽  
YOUNG RANG UHM ◽  
CHANG KYU RHEE
Keyword(s):  
Acetic Acid ◽  
Morphological Changes ◽  
Distilled Water ◽  
X Ray Diffraction ◽  
Temperature Method ◽  
Diffraction Patterns ◽  
Rapid Hydrolysis ◽  
Zno Powder ◽  
Hydrolysis Of

ZnO with 2D flower-like and 1D rod shape were obtained from simple and rapid hydrolysis of Zn nanopowder. The Zn nanopowders were incorporated into distilled water with acetic acid and then the solution was stirred at 60°C for 8 h. The nanoflower-like and rod shape were formed without any surfactant. It seems that the acetic acid played a role of controlling PH and etching the oxide layer on the surface of metal nanopowders to enhance rapid reaction with distilled water. X-ray diffraction patterns for all samples exhibited that the resultant precipitates were completely transformed to ZnO powder. It is clearly observed that the morphological changes of ZnO with reaction time in aqueous solution follows chestnut bur → flower → tetrahedron → rod sequences during the hydrolysis reaction.

scholarly journals “Newton’s cradle” proton relay with amide–imidic acid tautomerization in inverting cellulase visualized by neutron crystallography

2015 ◽  
Vol 1 (7) ◽  
pp. e1500263 ◽  
Author(s):  
Akihiko Nakamura ◽  
Takuya Ishida ◽  
Katsuhiro Kusaka ◽  
Taro Yamada ◽  
Shinya Fushinobu ◽  
...  
Keyword(s):  
Glycoside Hydrolases ◽  
Side Chain ◽  
Enzymatic Reactions ◽  
X Ray Diffraction ◽  
Peptide Bonds ◽  
Proton Relay ◽  
Newton’S Cradle ◽  
Dynamics Simulations ◽  
Hydrolysis Of

Hydrolysis of carbohydrates is a major bioreaction in nature, catalyzed by glycoside hydrolases (GHs). We used neutron diffraction and high-resolution x-ray diffraction analyses to investigate the hydrogen bond network in inverting cellulase PcCel45A, which is an endoglucanase belonging to subfamily C of GH family 45, isolated from the basidiomycete Phanerochaete chrysosporium. Examination of the enzyme and enzyme-ligand structures indicates a key role of multiple tautomerizations of asparagine residues and peptide bonds, which are finally connected to the other catalytic residue via typical side-chain hydrogen bonds, in forming the “Newton’s cradle”–like proton relay pathway of the catalytic cycle. Amide–imidic acid tautomerization of asparagine has not been taken into account in recent molecular dynamics simulations of not only cellulases but also general enzyme catalysis, and it may be necessary to reconsider our interpretation of many enzymatic reactions.

scholarly journals Kinetics and Mechanism of Hydrolysis of Acetylthiocholine by Butyrylcholine Esterase

2002 ◽  
Vol 57 (11-12) ◽  
pp. 1072-1077 ◽  
Author(s):  
Karel Komers ◽  
Alexandr Čegan ◽  
Marek Link
Keyword(s):  
Acetic Acid ◽  
Kinetics And Mechanism ◽  
Kinetics Parameters ◽  
Mechanism Of Hydrolysis ◽  
Ph Stat ◽  
Stat Method ◽  
Ellman’S Method ◽  
Hydrolysis Of

Kinetics and mechanism of hydrolysis of acetylthiocholine by the enzyme butyrylcholine esterase was studied. The spectrophotometric Ellman’s method and potentiometric pH-stat method were used for continuous determination of the actual concentration of the products thiocholine and acetic acid in the reaction mixture. The validity of the Michaelis-Menten (Briggs-Haldane) equation in the whole course of the reaction under used conditions was proved. The corresponding kinetics parameters (Vm and KM) were calculated from the obtained dependences of concentration of thiocholine or acetic acid vs. time and compared. From this comparison the deciding kinetic role of the step producing thiocholine was derived. The values of initial molar concentration of the enzyme and of the rate constants of the kinetic model were estimated.

Hydrolysis of Zirconium Propoxide by an Esterification Reaction

1992 ◽  
Vol 271 ◽  
Author(s):  
I. Laaziz ◽  
A. Larbot ◽  
C. Guizard ◽  
A. Julbe ◽  
L. Cot
Keyword(s):  
Acetic Acid ◽  
Light Scattering ◽  
Crystalline Structure ◽  
Structure Determination ◽  
Nmr Spectra ◽  
Esterification Reaction ◽  
Zirconium Propoxide ◽  
Size Growth ◽  
Hydrolysis Of

ABSTRACTZirconium propoxide hydrolysis was performed with the help of an esterification reaction using acetic acid. Products, obtained according to the value of hydrolysis ratio, are successively crystals, sols and gels or precipitates. The similarity of FUR and NMR spectra for crystals and gels allows to think that the arrangements of ligands around the zirconium atoms are close. The crystalline structure determination permits to precise the environment : acetate groups are always bridging and propoxy groups can be bridging or terminal. Clusters containing 9 zirconium atoms, bridged by oxygen atoms, exist in the structure. The colloid size growth was performed by light scattering. A discussion of the role of acetic acid and the competition between the possible reactions is given.

Novel Synthesis of Nanorod ZnO and Fe-Doped ZnO by the Hydrolysis of Metal Powders

2007 ◽  
Vol 7 (11) ◽  
pp. 4158-4160 ◽  
Author(s):  
B. S. Han ◽  
Y. R. Uhm ◽  
G. M. Kim ◽  
C. K. Rhee
Keyword(s):  
Wave Length ◽  
Zno Nanorods ◽  
Fe Doping ◽  
Metal Powders ◽  
Resolution Limit ◽  
X Ray Diffraction ◽  
Fe Content ◽  
Doped Zno ◽  
Diffraction Patterns ◽  
Hydrolysis Of

Fe-doped ZnO nanorods have been synthesized by a novel process employing a hydrolysis of metal powders. Zn and Fe nano-powders were used as starting materials and incorporated into distilled water. The solution was refluxed at 60 °C for 24 h to obtain the precipitates from the hydrolysis of Zn and Fe. X-ray diffraction patterns for all the samples showed a pure wurtzite single phase, without any segregation of the Fe into the particulates within the instrumental resolution limit. The TEM results for ZnO with and without an Fe-doping showed that the produced powders had a rod-like shape. The rod shape was attributable to the zinc oxide from the hydrolysis of Zn. With an increasing Fe content, the UV–vis spectra were shifted to a long wave length and this result indicates that the band gap was changed by an Fe-doping.

THE ROLE OF LIPOIDS IN THE X-RAY DIFFRACTION PATTERNS OF NERVE

Science ◽  
1935 ◽  
Vol 82 (2115) ◽  
pp. 44-45 ◽  
Author(s):  
F. O. Schmitt ◽  
R. S. Bear ◽  
G. L. Clark
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

Novel Synthesis of Nanorod ZnO and Fe-Doped ZnO by the Hydrolysis of Metal Powders

2007 ◽  
Vol 7 (11) ◽  
pp. 4158-4160
Author(s):  
B. S. Han ◽  
Y. R. Uhm ◽  
G. M. Kim ◽  
C. K. Rhee
Keyword(s):  
Wave Length ◽  
Zno Nanorods ◽  
Fe Doping ◽  
Metal Powders ◽  
Resolution Limit ◽  
X Ray Diffraction ◽  
Fe Content ◽  
Doped Zno ◽  
Diffraction Patterns ◽  
Hydrolysis Of

Fe-doped ZnO nanorods have been synthesized by a novel process employing a hydrolysis of metal powders. Zn and Fe nano-powders were used as starting materials and incorporated into distilled water. The solution was refluxed at 60 °C for 24 h to obtain the precipitates from the hydrolysis of Zn and Fe. X-ray diffraction patterns for all the samples showed a pure wurtzite single phase, without any segregation of the Fe into the particulates within the instrumental resolution limit. The TEM results for ZnO with and without an Fe-doping showed that the produced powders had a rod-like shape. The rod shape was attributable to the zinc oxide from the hydrolysis of Zn. With an increasing Fe content, the UV–vis spectra were shifted to a long wave length and this result indicates that the band gap was changed by an Fe-doping.

Franconite, NaNb2O5(OH)·3H2O: structure determination and the role of H bonding, with comments on the crystal chemistry of franconite-related minerals

2014 ◽  
Vol 78 (3) ◽  
pp. 591-607 ◽  
Author(s):  
M. M. M. Haring ◽  
A. M. McDonald
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Molecular Sieves ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Synthetic Compounds ◽  
X Ray ◽  
Distorted Octahedral ◽  
Diffraction Patterns

AbstractThe crystal structure of franconite, NaNb2O5(OH)·3H2O, has been characterized by single-crystal X-ray diffraction using material from Mont Saint-Hilaire, Québec, Canada. Results givea= 10.119(2),b= 6.436(1),c= 12.682(2) Å and β = 99.91(3)° and confirm the correct space group asP21/c. The crystal structure, refined toR= 4.63% andwR2=11.95%, contains oneNasite, two distorted octahedralNbsites and nineOsites. It consists of clusters of four edge-sharing Nb(O,OH)6octahedra, linked through shared corners to adjacent clusters, forming layers of Nb(O,OH)6octahedra. These alternate along [100] with layers composed of NaO(H2O)4polyhedra, the two being linked together by well defined H bonding. The predominance of H bonding, essential to the mineral, results in a perfect {100} cleavage. Chemical analyses (n= 7) of four crystals give the empirical formula (Na0.73Ca0.13☐0.14)∑=1.00(Nb1.96Ti0.02Si0.02Al0.01)∑=2.01O5(OH)·3H2O (based on nine oxygens) or ideally NaNb2O5(OH)·3H2O. Franconite is crystallo-chemically related to SOMS [Sandia Octahedral Molecular Sieves; Na2Nb2−xMxO6−x(OH)x·H2O with M = Ti, Zr, Hf], a group of synthetic compounds with strong ion-exchange capabilities. Both hochelagaite (CaNb4O11·nH2O) and ternovite (MgNb4O11·nH2O) have X-ray powder diffraction patterns and cation ratios similar to those of franconite indicating that these minerals probably have similar structures.

scholarly journals THE ROLE OF WATER IN THE STRUCTURE OF PERIPHERAL NERVE MYELIN

1957 ◽  
Vol 3 (1) ◽  
pp. 95-102 ◽  
Author(s):  
J. B. Finean
Keyword(s):  
Water Distribution ◽  
Water Evaporation ◽  
X Ray Diffraction ◽  
Nerve Fibres ◽  
Diffraction Patterns ◽  
Protein Components ◽  
Five Phases ◽  
Kinetics Of ◽  
Frog Sciatic Nerve

In the study of the drying kinetics of nerve fibres, at least five "phases" of water evaporation can be distinguished. A consideration of the accompanying changes in low-angle x-ray diffraction patterns permits a tentative identification of the "phases" and a quantitative interpretation of the data in terms of the water distribution in nerve fibres. These results suggest that the myelin sheath of frog sciatic nerve contains 40 to 50 per cent water, and it is suggested further that the greater part of this water is "organised" in relation to the hydrophilic groups of the lipide and protein components.

Hydrolysis of O-Acetylsalicylic Acid (Aspirin) in Relation to the Aspirin-Bromate-Acid Oscillating System

2006 ◽  
Vol 71 (10) ◽  
pp. 1445-1452 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Daniel Mišicák ◽  
Peter Ševčík
Keyword(s):  
Acetic Acid ◽  
Salicylic Acid ◽  
Acetylsalicylic Acid ◽  
Induction Period ◽  
Rate Constant ◽  
Degradation Products ◽  
Oscillatory Behavior ◽  
Active Substrate ◽  
Hydrolysis Of

The uncatalyzed BrO3--O-acetylsalicylic acid (aspirin) reaction in aqueous H2SO4 exhibits oscillatory behavior. The induction period observed before the onset of oscillations depends on the extent of hydrolysis of aspirin. The rate constant of hydrolysis of aspirin was determined indirectly from the value of induction period. When aspirin undergoes hydrolysis, the degradation products are salicylic acid and acetic acid. Salicylic acid may play a role of "active" substrate responsible for the oscillations. Aspirin (Bayer) generates also oscillations with bromate.

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