Measurement of diffusion coefficients

Crooks, J. E.

doi:10.1021/ed066p614

Cited by 11 publications

(11 citation statements)

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“…For 90CE, this value calculates to be 913 µm 2 s -1 and very similar values (within 20%) are calculated for other BSHs. Using the simple methodology described by Crooks [ 57 ] and acidified solutions (pH ≤ 3.0 to block BSH activation/decomposition), these diffusion coefficients could be easily measured directly. Diffusion through cells and tissues is generally a slower process because of a number of factors, including the need to traverse multiple membranes, cytoplasmic viscosity, etc .…”

Section: Correlating Bsh Half-life With Cytotoxic Activity Radius/ranmentioning

confidence: 99%

Physicochemical Considerations of Tumor Selective Drug Delivery and Activity Confinement with Particular Reference to 1,2-Bis(Sulfonyl)-1- Alkylhydrazines Delivery

Penketh

Williamson

Shyam

2020

CDD

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: Hypoxic tumor cell sub-populations are highly resistant to radiotherapy and their presence frequently causes disease recurrence and death. Here we describe the physicochemical properties required to develop superior tumor targeted hypoxia-activated modular prodrugs that liberate extremely short-lived bis(sulfonyl)hydrazines (BSHs) as reactive cytotoxins, thereby precisely focusing cytotoxic stress on these radio-resistant hypoxic sub-populations. Utilizing the strategy described new agents will be possible that more precisely confine/focus cytotoxic stress on radiation resistant areas and will thus strongly synergize with radiotherapy.

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Section: Correlating Bsh Half-life With Cytotoxic Activity Radius/ranmentioning

confidence: 99%

Physicochemical Considerations of Tumor Selective Drug Delivery and Activity Confinement with Particular Reference to 1,2-Bis(Sulfonyl)-1- Alkylhydrazines Delivery

Penketh

Williamson

Shyam

2020

CDD

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“…The glucose concentration in the banana juice was adjusted at 20 g/L and replaced every 15 min during the assay to maintain the steady-state condition [42]. Equation (3) [43] was used to calculate the diffusivity coefficient.…”

Section: Scale-up Of the Bioreactormentioning

confidence: 99%

A Novel Approach Using Conventional Methodologies to Scale up BNC Production Using Komagataeibacter medellinensis and Rotten Banana Waste as Alternative

et al. 2020

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Currently, cellulose nanostructures are among the most promising structures, and extensive work in materials and biotechnology industries is aimed at identifying an efficient process of production. Even when production at the laboratory scale is successful, crucial aspects of increased commercial applications for cellulose nanostructures are linked to large-scale production. Large-scale production requires a balance between the cost of the culture medium and product value. Therefore, in this work, for the optimization and scaling up of bacterial nanocellulose, a culture medium consisting of rotten banana unsuitable for human consumption was used for the first time as an inexpensive feedstock. Initially, the bacterial nanocellulose (BNC) culture medium conditions were optimized, and it was established that a glucose concentration of 26.4 g/L and a V/A ratio of 2.2 cm were the optimal conditions for production reaching a BNC yield of 5 g/L, which was 42.4% higher than the best result initially obtained. Finally, the scale-up process was performed, implementing a regime analysis methodology by comparing the characteristic times of the critical mechanisms involved in BNC production, namely, microbial growth, glucose consumption, BNC production, and glucose diffusion into the BNC membrane, as the first approach for this type of BNC production process. The mechanism underlying the BNC production process is glucose diffusion into the BNC membrane (characteristic time, 675.47 h). Thus, the V/A ratio was selected as the scale-up criterion most suitable for producing BNC under static culture conditions, allowing the production of 16 g of BNC after 12 d of fermentation in a plastic bioreactor, which was 3378% higher than that produced in glass vessels. The results obtained in this study may initiate further improvements in BNC commercial production by exploiting different feedstocks.

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“…The method proposed for the determination of diffusion coefficient of Fe 3+ ions into EDBreast is based on the one published by Crooks [22]. In his method, Crooks has considered that diffusion occurred in a semi-infinite media which relies on the mathematical modeling of the diffusion proposed by Hadgaft [25].…”

Section: Absorption Spectroscopy Measurementsmentioning

confidence: 99%

“…It is difficult to find a convenient laboratory technique for measurement of diffusion. John E Crooks describes a simple experimental system to measure quickly diffusion coefficients [22].…”

Section: Introductionmentioning

confidence: 99%

A new spectroscopic method for measuring ferric diffusion coefficient in gelatin-based dosimeter gels

Coulaud

Stien

Gonneau

et al. 2019

Biomed. Phys. Eng. Express

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A new absorption spectroscopy method which enables rapid measurement of the diffusion coefficient of Fe 3+ in gelatin gel used in dosimetry was investigated. The physical approach, the preparation and the experimental application of this new method were tested on the EasyDosit dosimetry gel and the results were validated by MRI measurement. The diffusion coefficients measured on this gel were then compared with those of the other gels presented in the literature. This gel, which is considered stable, has a small post-irradiation ion diffusion, despite the absence of a complexing or crosslinking agent. The diffusion coefficients of a range of dosimetry gels containing different proportions of gelatin were also measured and the results show diffusion coefficients D from 3.21.10 −10 m 2 .s −1 to 2.41.10 −10 m 2 .s −1 .

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Measurement of diffusion coefficients

Abstract: Ensuring that solute movement is due solely to diffusion (and not bulk movement) by holding the liquid in a gel.

Cited by 11 publications

References 0 publications

Physicochemical Considerations of Tumor Selective Drug Delivery and Activity Confinement with Particular Reference to 1,2-Bis(Sulfonyl)-1- Alkylhydrazines Delivery

Physicochemical Considerations of Tumor Selective Drug Delivery and Activity Confinement with Particular Reference to 1,2-Bis(Sulfonyl)-1- Alkylhydrazines Delivery

A Novel Approach Using Conventional Methodologies to Scale up BNC Production Using Komagataeibacter medellinensis and Rotten Banana Waste as Alternative

A new spectroscopic method for measuring ferric diffusion coefficient in gelatin-based dosimeter gels

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