Rational design of carbon support to prepare ultrafine iron oxide catalysts for air oxidation of alcohols
38
Citation
52
Reference
10
Related Paper
Citation Trend
Abstract:
The efficient carbon supports change not only the physical but also the chemical properties of iron oxide and create new active sites for the enhancement of catalytic activity in the oxidation of alcohols with air as an oxygen source.Keywords:
Rational design
Carbon fibers
Alcohol Oxidation
The paper had a design on the programmed temperature rising experiment of the loose coal under the different oxygen supply conditions.A gas chromatograph chromatography was applied to the analysis on the oxygen concentration of the outlet air under the rated temperature during the temperature rising process.The oxygen consumption rate of the coal sample with different oxygen concentration and under the rated temperature was calculated,a comparison was conducted on the oxygen consumption rates of the coal samples at each temperature point and under the different oxygen concentration condition and a fitting was conducted on the oxygen consumption rate and oxtgen concentration under the certain temperature.The results showed that under the different oxygen concentration condition,the oxygen consumption rate of the loose coal would be increased with the temperature increased.The oxygen concentration would affect the oxygen consumption rate and would have no obvious influence to the oxygen consumption rate with the temperature varied.Under the same temperature,the oxygen consumption rate of the coal sample would be increased with the oxygen concentration increased and the oxygen consumption rate and the logarithmic relationship between the oxygen supplied concentration could be met.
Limiting oxygen concentration
Cite
Citations (1)
Rational design
Protein Engineering
Directed Molecular Evolution
Synthetic Biology
Cite
Citations (394)
Objective To study the relationships between supplied oxygen concentration (FsO_ 2 ), flow rate (flow) and inhaled oxygen concentration (FiO_ 2 ) in neonates when oxygen is given via oxygen hood; and to study what are the most effective ways of supplying oxygen in neonates. Methods Oxygen concentrations were measured in nasal cavities of neonates when different FsO_ 2 and Flow were given. FsO_ 2 and Flow were adjusted and measured by Air-oxygen blender and Pigeon I analyzer. Results When FsO_ 2 was 100% and Flow was greater than 3 L/min, the oxygen concentration measured in nasal cavities of neonate was greater than 40% in all groups with different sizes of oxygen hood; when Flow was increased to or greater than 7L/min, the oxygen concentrations in nasal cavities of neonate were close to 60% for groups with medium and big oxygen hood and greater than 60% for groups with small oxygen hood. Among the groups with same size oxygen hood, the difference of oxygen concentration in nasal cavities showed statistical significance (P0.01) when FsO_ 2 was equal to or greater than 21%. The oxygen concentrations in nasal cavities and the changes of FsO_ 2 and Flow showed linear relationships (P=0.000) in all studied groups with three different sizes of oxygen hood. Conclusions When oxygen is given via oxygen hood, FiO_ 2 changes in a wide range with the changes of FsO_ 2 and Flow; when 100 % oxygen is given, low flow is required to keep FiO_2 in a satisfied range. Therefore, for the safety of oxygen supply, it is important to use air-oxygen blender to choose the right FsO_2 and flow when oxygen is given via oxygen hood.
Limiting oxygen concentration
Oxygen delivery
Oxygene
Cite
Citations (0)
Consumption
American lobster
Cite
Citations (25)
Rational design
Cite
Citations (14)
Oxygen delivery
Cite
Citations (27)
Scanning tunneling microscopy and atomic force microscopy have been used to study iron single crystals with various oxide layers on the surfaces. The results show that at 4.2 K the thin layer oxide yields a very low barrier height of approximately 0.020 to 0.100 eV. The consequent dI/dV versus V curves are extremely nonlinear. This is consistent with the earlier results obtained on metal-iron oxide-metal junctions. The barrier height variation as a function of distance is also represented. A numerical calculation using the Fowler-Nordheim expression produced a good fit to the characteristic tunneling curves. Due to a low tunneling barrier, room temperature STM images of internal oxide structure are possible on samples with thick iron oxide layers formed at high temperatures. Large scale STM scans shows layered growth patterns and stepped structures. In contrast, AFM scans show the surface structure of oxide layers. STM and AFM, therefore, can be used to study all stages of iron oxidation including the early stages and the advanced stages.
Atomic units
Cite
Citations (0)
The presence of low levels of oxygen may have profound effects on the cytotoxic activity of radiation, radiosensitizers, and bioreductive alkylating agents. As others have shown, low oxygen tensions may significantly alter rates of cellular and chemical oxygen consumption. When experiments are performed at very low oxygen concentrations, the opposing effects of oxygen leakage into and cellular/chemical oxygen consumption from the system can lead to unpredictable results. Use of a newly designed, highly sensitive Clark-type oxygen sensor has permitted accurate and reproducible measurement of low levels of oxygen. Cellular depletion of oxygen at various cell densities has been monitored for a series of oxygen tensions in solution and the corresponding respiration rates have been calculated. Although oxygen depletion was found to be quite significant at low oxygen tensions, not all oxygen present could be removed by cellular respiration. Respiration rate decreased as oxygen tension decreased and approached zero at low oxygen tensions. This result was independent of cell density. A model is presented to account for the observed effect of oxygen tension on cellular oxygen utilization.
Oxygen tension
Limiting oxygen concentration
Cellular respiration
Apparent oxygen utilisation
Oxygen enhancement ratio
Oxygene
Cite
Citations (27)
Many research groups successfully rely on whole-gene random mutagenesis and recombination approaches for the directed evolution of enzymes.Recent advances in enzyme engineering have used a combination of these random methods of directed evolution with elements of rational enzyme modification to successfully by-pass certain limitations of both directed evolution and rational design.Semi-rational approaches that target multiple,specific residues to mutate on the basis of prior structural or functional knowledge create 'smart' libraries that are more likely to yield positive results.Efficient sampling of mutations likely to affect enzyme function has been conducted to both experiment and on a much greater scale,computation,with remarkable improvements in substrate selectivity and specificity and in the redesign of enzyme activities within known structure.
Rational design
Protein Engineering
Directed Molecular Evolution
Cite
Citations (2)
The strategy of rational design to engineer enzymes is to predict the potential mutants based on the understanding of the relationships between protein structure and function, and subsequently introduce the mutations using the site-directed mutagenesis. Rational design methods are universal, relatively fast and have the potential to be developed into algorithms that can quantitatively predict the performance of the designed sequences. Compared to the protein stability, it was more challenging to design an enzyme with improved activity or selectivity, due to the complexity of enzyme molecular structure and inadequate understanding of the relationships between enzyme structures and functions. However, with the development of computational force, advanced algorithm and a deeper understanding of enzyme catalytic mechanisms, rational design could significantly simplify the process of engineering enzyme functions and the number of studies applying rational design strategy has been increasing. Here, we reviewed the recent advances of applying the rational design strategy to engineer enzyme functions including activity and enantioselectivity. Five strategies including multiple sequence alignment, strategy based on steric hindrance, strategy based on remodeling interaction network, strategy based on dynamics modification and computational protein design are discussed and the successful cases using these strategies are introduced.
Rational design
Protein design
Protein Engineering
Cite
Citations (58)