scholarly journals Factors determining the sequence of oxidative decarboxylation of the 2- and 4-propionate substituents of coproporphyrinogen III by coproporphyrinogen oxidase in rat liver

1978 ◽  
Vol 169 (1) ◽  
pp. 215-223 ◽  
Author(s):  
George H. Elder ◽  
J. Olwyn Evans ◽  
J. Richard Jackson ◽  
Anthony H. Jackson
Keyword(s):  
Rat Liver ◽  
Competitive Inhibition ◽  
Experimental Results ◽  
The Other ◽  
Oxidative Decarboxylation ◽  
Active Centre ◽  
Coproporphyrinogen Oxidase ◽  
Propionate Group ◽  
Carboxyl Carbon

Coproporphyrinogen oxidase (EC 1.3.3.3) catalyses the oxidative decarboxylation of the 2- and 4-propionate substituents of coproporphyrinogen III to form protoporphyrinogen IX. A 4-propionate-substituted porphyrinogen, harderoporphyrinogen, which is also a substrate for coproporphyrinogen oxidase, is formed during the reaction. Synthetic [14C]coproporphyrinogens III, specifically labelled in the carboxyl carbon atoms of either the 2- or 4-propionate substituents, were used to measure the rate of decarboxylation of each substituent by rat liver coproporphyrinogen oxidase. The experimental results, together with the recognition that in all known substrates of coproporphyrinogen oxidase only those propionate groups flanked by a specific arrangement of substituents are decarboxylated, indicate that the 4-propionate group of coproporphyrinogen III cannot be attacked until the 2-propionate group has been decarboxylated. Production of 14CO2 from the substrate labelled in the 2-propionate group therefore measures the formation of harderoporphyrinogen, whereas 14CO2 from the 4-propionate-labelled substrate measures protoporphyrinogen IX formation. The rate of harderoporphyrinogen formation is about twice that of protoporphyrinogen, and this ratio is unchanged by varying the concentration of coproporphyrinogen III or by competitive inhibition of the enzyme. When coproporphyrinogen III is present in an excess, two fractions of harderoporphyrinogen can be distinguished. One accumulates during the reaction, and the other, which is destined to become protoporphyrinogen IX, does not equilibrate with added harderoporphyrinogen. It is suggested that both decarboxylations take place at the same active centre, which becomes temporarily inaccessible to coproporphyrinogen III and added harderoporphyrinogen, and that the molecule rotates after the first decarboxylation to allow the second to take place.

scholarly journals A radiochemical method for the measurement of coproporphyrinogen oxidase and the utilization of substrates other than coproporphyrinogen III by the enzyme from rat liver

1978 ◽  
Vol 169 (1) ◽  
pp. 205-214 ◽  
Author(s):  
G H Elder ◽  
J O Evans
Keyword(s):  
Rat Liver ◽  
Protoporphyrin Ix ◽  
Competitive Inhibitor ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Sensitive Assay ◽  
Radiochemical Method ◽  
Mixed Substrate ◽  
Coproporphyrinogen Oxidase ◽  
Carboxyl Carbon

[14C2]Coproporphyrin III, 14C-labelled in the carboxyl carbon atoms of the 2- and 4-propionate substituents, was prepared by stepwise modification of the vinyl groups of protoporphyrin IX. The corresponding porphyrinogen was used as substrate in a specific sensitive assay for coproporphyrinogen oxidase (EC 1.3.3.3) in which the rate of production of 14CO2 is measured. With this method, the Km of the enzyme from rat liver for coproporphyrinogen III is 1.2 micron. Coproporphyrin III is a competitive inhibitor of the enzyme (Ki 7.6 micron). Apparent Km values for other substrates were measured by a mixed-substrate method: that for coproporphyrinogen IV is 0.9 micron and that for harderoporphyrinogen 1.6 micron. Rat liver mitochondria convert pentacarboxylate porphyrinogen III into dehydroisocoproporphyrinogen at a rate similar to that for the formation of protoporphyrinogen IX from coproporphyrinogen III. Mixed-substrate experiments indicate that this reaction is catalysed by coproporphyrinogen oxidase and that the Km for this substrate is 29 micron. It is suggested that the ratio of the concentration of pentacarboxylate porphyrinogen III to coproporphyrinogen III in the hepatocyte determines the relative rates of formation of dehydroisocoproporphyrinogen and protoporphyrinogen IX.

The Influence of Water Regime on the Performance of Aquatic Plants

1994 ◽  
Vol 29 (4) ◽  
pp. 127-132 ◽  
Author(s):  
Naomi Rea ◽  
George G. Ganf
Keyword(s):  
Deep Water ◽  
Aquatic Plants ◽  
Water Regime ◽  
Optimal Performance ◽  
Experimental Results ◽  
The Other ◽  
Full Potential ◽  
Influence Of Water ◽  
Emergent Species

Experimental results demonstrate bow small differences in depth and water regime have a significant affect on the accumulation and allocation of nutrients and biomass. Because the performance of aquatic plants depends on these factors, an understanding of their influence is essential to ensure that systems function at their full potential. The responses differed for two emergent species, indicating that within this morphological category, optimal performance will fall at different locations across a depth or water regime gradient. The performance of one species was unaffected by growth in mixture, whereas the other performed better in deep water and worse in shallow.

scholarly journals THE INCORPORATION OF THE CARBOXYL CARBON FROM ACETATE INTO CHOLESTEROL BY RAT LIVER HOMOGENATES

1954 ◽  
Vol 206 (1) ◽  
pp. 471-481 ◽  
Author(s):  
Ivan D. Frantz ◽  
Nancy L.R. Bucher ◽  
Henny S. Schneider ◽  
Naomi H. McGovern ◽  
Ruth Kingston
Keyword(s):  
Rat Liver ◽  
Liver Homogenates ◽  
Carboxyl Carbon

Mining discriminative patches for script identification in natural scene images

2021 ◽  
Vol 40 (1) ◽  
pp. 551-563
Author(s):  
Liqiong Lu ◽  
Dong Wu ◽  
Ziwei Tang ◽  
Yaohua Yi ◽  
Faliang Huang
Keyword(s):  
Neural Networks ◽  
Experimental Results ◽  
The Other ◽  
Natural Scene ◽  
Fixed Size ◽  
Script Identification ◽  
Aspect Ratios ◽  
Novel Approach ◽  
Public Datasets ◽  
Natural Scene Images

This paper focuses on script identification in natural scene images. Traditional CNNs (Convolution Neural Networks) cannot solve this problem perfectly for two reasons: one is the arbitrary aspect ratios of scene images which bring much difficulty to traditional CNNs with a fixed size image as the input. And the other is that some scripts with minor differences are easily confused because they share a subset of characters with the same shapes. We propose a novel approach combing Score CNN, Attention CNN and patches. Attention CNN is utilized to determine whether a patch is a discriminative patch and calculate the contribution weight of the discriminative patch to script identification of the whole image. Score CNN uses a discriminative patch as input and predict the score of each script type. Firstly patches with the same size are extracted from the scene images. Secondly these patches are used as inputs to Score CNN and Attention CNN to train two patch-level classifiers. Finally, the results of multiple discriminative patches extracted from the same image via the above two classifiers are fused to obtain the script type of this image. Using patches with the same size as inputs to CNN can avoid the problems caused by arbitrary aspect ratios of scene images. The trained classifiers can mine discriminative patches to accurately identify some confusing scripts. The experimental results show the good performance of our approach on four public datasets.

scholarly journals DV-DVFS: merging data variety and DVFS technique to manage the energy consumption of big data processing

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hossein Ahmadvand ◽  
Fouzhan Foroutan ◽  
Mahmood Fathy
Keyword(s):  
Big Data ◽  
Energy Consumption ◽  
Processing Time ◽  
Experimental Results ◽  
The Other ◽  
Data Sets ◽  
Multiple Sources ◽  
Evaluation Phase ◽  
Dynamic Voltage ◽  
Processing Resources

AbstractData variety is one of the most important features of Big Data. Data variety is the result of aggregating data from multiple sources and uneven distribution of data. This feature of Big Data causes high variation in the consumption of processing resources such as CPU consumption. This issue has been overlooked in previous works. To overcome the mentioned problem, in the present work, we used Dynamic Voltage and Frequency Scaling (DVFS) to reduce the energy consumption of computation. To this goal, we consider two types of deadlines as our constraint. Before applying the DVFS technique to computer nodes, we estimate the processing time and the frequency needed to meet the deadline. In the evaluation phase, we have used a set of data sets and applications. The experimental results show that our proposed approach surpasses the other scenarios in processing real datasets. Based on the experimental results in this paper, DV-DVFS can achieve up to 15% improvement in energy consumption.

Study of wave attenuation in concrete

1993 ◽  
Vol 8 (9) ◽  
pp. 2344-2353 ◽  
Author(s):  
J-M. Berthelot ◽  
Souda M. Ben ◽  
J.L. Robert
Keyword(s):  
Experimental Study ◽  
Plane Wave ◽  
Wave Attenuation ◽  
Plane Waves ◽  
Propagation Distance ◽  
Experimental Results ◽  
The Other ◽  
Wave Frequency ◽  
Concrete Composition ◽  
Analytical Expression

The experimental study of wave attenuation in concrete has been achieved in the case of the propagation of plane waves in concrete rods. Different mortars and concretes have been investigated. A transmitter transducer coupled to one of the ends of the concrete rod generates the propagation of a plane wave in the rod. The receiver transducer, similar to the previous one, is coupled to the other end of the rod. The experimental results lead to an analytical expression for wave attenuation as function of the concrete composition, the propagation distance, and the wave frequency.

scholarly journals The fractionation of nuclei from mammalian cells by zonal centrifugation

1968 ◽  
Vol 109 (1) ◽  
pp. 127-135 ◽  
Author(s):  
I R Johnston ◽  
A P Mathias ◽  
F. Pennington ◽  
D. Ridge
Keyword(s):  
Rat Liver ◽  
Mammalian Cells ◽  
Mouse Liver ◽  
The Other ◽  
Slow Speed ◽  
Adult Rats ◽  
Sucrose Solutions ◽  
Liver Nuclei ◽  
Effect Of Age ◽  
Zonal Rotor

1. Purified liver nuclei from adult rats separate into two main zones when centrifuged in the slow-speed zonal rotor. One zone contains diploid nuclei, the other tetraploid. 2. The effect of age on the pattern of rat liver ploidy was examined. Tetraploid nuclei are virtually absent from young animals. They increase in proportion steadily with age. Partial hepatectomy disturbs the pattern of ploidy. 3. The zonal centrifuge permits the separation of diploid, tetraploid, octaploid and hexadecaploid nuclei from mouse liver. 4. Rat liver nuclei are isopycnic with sucrose solutions of density 1·35 at 5°.

scholarly journals GazeEMD: Detecting Visual Intention in Gaze-Based Human-Robot Interaction

Robotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 68
Author(s):  
Lei Shi ◽  
Cosmin Copot ◽  
Steve Vanlanduit
Keyword(s):  
Cognitive Load ◽  
Real World ◽  
Robotic Manipulator ◽  
Similarity Score ◽  
Human Robot Interaction ◽  
Experimental Results ◽  
The Other ◽  
Robot Interaction ◽  
Run Length ◽  
The Real

In gaze-based Human-Robot Interaction (HRI), it is important to determine human visual intention for interacting with robots. One typical HRI interaction scenario is that a human selects an object by gaze and a robotic manipulator will pick up the object. In this work, we propose an approach, GazeEMD, that can be used to detect whether a human is looking at an object for HRI application. We use Earth Mover’s Distance (EMD) to measure the similarity between the hypothetical gazes at objects and the actual gazes. Then, the similarity score is used to determine if the human visual intention is on the object. We compare our approach with a fixation-based method and HitScan with a run length in the scenario of selecting daily objects by gaze. Our experimental results indicate that the GazeEMD approach has higher accuracy and is more robust to noises than the other approaches. Hence, the users can lessen cognitive load by using our approach in the real-world HRI scenario.

Natural Vulcanization Accelerators in Hevea Latex

1948 ◽  
Vol 21 (4) ◽  
pp. 853-859
Author(s):  
R. F. A. Altman
Keyword(s):  
Amino Acids ◽  
Experimental Results ◽  
The Other ◽  
Active Nitrogen ◽  
Nitrogen Bases ◽  
Other Hand ◽  
Decomposition Processes ◽  
Volatile Products ◽  
Nitrogenous Substances ◽  
The One

Abstract As numerous investigators have shown, some of the nonrubber components of Hevea latex have a decided accelerating action on the process of vulcanization. A survey of the literature on this subject points to the validity of certain general facts. 1. Among the nonrubber components of latex which have been investigated, certain nitrogenous bases appear to be most important for accelerating the rate of vulcanization. 2. These nitrogen bases apparently occur partly naturally in fresh latex, and partly as the result of putrefaction, heating, and other decomposition processes. 3. The nitrogen bases naturally present in fresh latex at later stages have been identified by Altman to be trigonelline, stachhydrine, betonicine, choline, methylamine, trimethylamine, and ammonia. These bases are markedly active in vulcanization, as will be seen in the section on experimental results. 4. The nitrogenous substances formed by the decomposition processes have only partly been identified, on the one hand as tetra- and pentamethylene diamine and some amino acids, on the other hand as alkaloids, proline, diamino acids, etc. 5. It has been generally accepted that these nitrogenous substances are derived from the proteins of the latex. 6. Decomposition appears to be connected with the formation of a considerable amount of acids. 7. The production of volatile nitrogen bases as a rule accompanies the decomposition processes. These volatile products have not been identified. 8. The active nitrogen bases, either already formed or derived from complex nitrogenous substances, seem to be soluble in water but only slightly soluble in acetone.

Screening of Coagulant for Washing Wastewater Treatment

2015 ◽  
Vol 1092-1093 ◽  
pp. 972-975
Author(s):  
Jing Yang
Keyword(s):  
Wastewater Treatment ◽  
Removal Rate ◽  
Experimental Results ◽  
The Other ◽  
Aluminium Chloride ◽  
Coagulation Tests ◽  
Cyclic Utilization ◽  
Washing Wastewater ◽  
Better Than

According to the problems exist in cyclic utilization of washing wastewater, the coagulation tests utilizing ferric trichloride (FeCl3), alums, poly aluminium chloride (PAC) and polyacrylamide (PAM) are studied, respectively. Experimental results show that PAC was much better than the other coagulants in the removal of LAS and chroma as a single coagulant. Cast 2.5mL PAC(10%) into quantitative washing wastewater, the removal rate of LAS and chroma reach 82.5% and 87.8%, respectively. When mix the every two kinds of coagulants, maintaining the same total amount of coagulant to 2.5mL, cast1.0mL PAC(10%) and 1.5mL alum (10%) into washing wastewater ,the removal rate of LAS and chroma reach 84.1% and 90.0%, respectively.

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