scholarly journals Optimization of the ultrasonic treatment for improving catalytic activity of glucoamylase preparation

2015 ◽  
Vol 18 (3) ◽  
pp. 52-59
Author(s):  
Tra Thi Thu Tran ◽  
Man Van Viet Le
Keyword(s):  
Catalytic Activity ◽  
Ultrasonic Treatment ◽  
Potential Method ◽  
Starch Hydrolysis ◽  
Glucoamylase Activity ◽  
Central Composite

In this work, ultrasonic treatment was used for improving the catalytic activity of glucoamylase preparation Dextrozyme GA. The ultrasonic temperature, power and time were optimized by a Central Composite Circumscribed design for maximizing of the catalytic activity of the preparation. The optimal ultrasonic temperature, power and time were 30oC, 20 W/mL and 33 sec, respectively. Under these conditions, the maximum glucoamylase activity was 83.142 ± 0.213 KU/mL and this value increased 11 % in comparison with that in the control without ultrasonic treatment. Our results also showed that Vmax and KM of the sonicated Dextrozyme GA preparation were higher than those of the control. The ultrasonic treatment would be a potential method for improving the catalytic activity of the glucoamylase preparation in starch hydrolysis.

Modelling an electrochemically roughened porous platinum electrode for water oxidation

2016 ◽  
Vol 52 (21) ◽  
pp. 4068-4071 ◽  
Author(s):  
Alexander Weremfo ◽  
Xunyu Lu ◽  
Paul Carter ◽  
D. Brynn Hibbert ◽  
Chuan Zhao
Keyword(s):  
Catalytic Activity ◽  
Central Composite Design ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Platinum Electrode ◽  
Pt Electrode ◽  
Central Composite

The use of a central composite design to model the roughness of an electrochemically roughened Pt electrode and the surface with a well-defined nanostructure exhibits greatly improved catalytic activity towards oxygen evolution reaction.

scholarly journals Atomically thin SiC nanoparticles obtained via ultrasonic treatment to realize enhanced catalytic activity for the oxygen reduction reaction in both alkaline and acidic media

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 22875-22881 ◽  
Author(s):  
Jiahao Guo ◽  
Kaiyue Song ◽  
Bingbing Wu ◽  
Xiang Zhu ◽  
Beilin Zhang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Ultrasonic Treatment ◽  
Reduction Reaction ◽  
Methanol Crossover ◽  
Acidic Media ◽  
Sic Nanoparticles

Atomically thin SiC derived from commercial SiC and possesses prominent ORR catalytic activity, comparable with Pt/C. The ORR process is dominated by a 4-electron pathway. Atomically thin SiC also exhibited outstanding durability and methanol crossover resistance.

scholarly journals Enhancement of catalytic activity in NH3-SCR reaction by promoting dispersibility of CuCe/TiO2-ZrO2 with ultrasonic treatment

2021 ◽  
Vol 72 ◽  
pp. 105466
Author(s):  
Wei Zhang ◽  
Yunhao Tang ◽  
Cheng Lu ◽  
Jiyao Zou ◽  
Min Ruan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Ultrasonic Treatment ◽  
Nh3 Scr

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).

Modulated structures in (Bi,Pb)-Sr-Ca-Cu-O films

1990 ◽  
Vol 48 (4) ◽  
pp. 62-63
Author(s):  
Shozo Ikeda ◽  
Hirotoshi Hayakawa ◽  
Daniel R. Dietderich
Keyword(s):  
Rf Magnetron Sputtering ◽  
Potential Method ◽  
High Tc ◽  
Bscco System ◽  
Heat Treated ◽  
Modulated Structures ◽  
High Tc Phase ◽  
Deposited Films ◽  
Sputtering System

Pb addition makes easier to form the high Tc phase in the BSCCO system. However, Pb easily vaporized at high temperature. A controlled Pb potential method has been applied to grow the high Tc phase in films. Initially, films are deposited on cleaved MgO substrates using an rf magnetron sputtering system. These amorphous as-deposited films are heat treated in a sealed gold capsule along with a large pellet of Pb-added BSCCO. Details of the process and characterization of the films have been reported elsewhere (1). Films trated for 0.5h at 850° C contain mainly the low Tc phase with a small amount of the high Tc phase. Hawever, films treated for 3h at 850°C consist mainly of the high Tc phase. This film is superconductive with a Tc(zero) of 106K. The Pb/Bi ratio of the films, analysed by SEM- EDS, are 0.12 and 0.18 for heat tratment times of 0.5 and 3h, respectively. The present study investigates the modulated structures of these films using HREM.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Development and optimization of solid lipid nanoparticles of amikacin by central composite design

2009 ◽  
Vol 00 (00) ◽  
pp. 090721051030036-8
Author(s):  
Jaleh Varshosaz ◽  
Solmaz Ghaffari ◽  
Mohammad Reza Khoshayand ◽  
Fatemeh Atyabi ◽  
Shirzad Azarmi ◽  
...  
Keyword(s):  
Central Composite Design ◽  
Solid Lipid Nanoparticles ◽  
Lipid Nanoparticles ◽  
Solid Lipid ◽  
Central Composite

Assays for Phospholipid-Dependent Formation of Thrombin and Xa: A Potential Method for Quantifying Lupus Anticoagulant Activity

1991 ◽  
Vol 66 (04) ◽  
pp. 453-458 ◽  
Author(s):  
John T Brandt
Keyword(s):  
Specific Activity ◽  
Anticoagulant Activity ◽  
Factor Xa ◽  
Clinical Importance ◽  
Potential Method ◽  
Quantitative Expression ◽  
Increased Risk ◽  
Apparent Association

SummaryLupus anticoagulants (LAs) are antibodies which interfere with phospholipid-dependent procoagulant reactions. Their clinical importance is due to their apparent association with an increased risk of thrombo-embolic disease. To date there have been few assays for quantifying the specific activity of these antibodies in vitro and this has hampered attempts to purify and characterize these antibodies. Methods for determining phospholipid-dependent generation of thrombin and factor Xa are described. Isolated IgG fractions from 7 of 9 patients with LAs were found to reproducibly inhibit enzyme generation in these assay systems, permitting quantitative expression of inhibitor activity. Different patterns of inhibitory activity, based on the relative inhibition of thrombin and factor Xa generation, were found, further substantiating the known heterogeneity of these antibodies. These systems may prove helpful in further purification and characterization of LAs.

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