A GAS CHROMATOGRAPHIC STUDY OF THE ADSORPTIVE PROPERTIES OF A SERIES OF ACTIVATED CHARCOALS

1959 ◽  
Vol 37 (5) ◽  
pp. 843-855 ◽  
Author(s):  
Henry W. Habgood ◽  
James F. Hanlan
Keyword(s):  
Gas Flow ◽  
Initial Slope ◽  
Chromatographic Retention ◽  
Chromatographic Study ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion ◽  
Retention Volumes ◽  
Carrier Gas Flow ◽  
Different Gases ◽  
Initial Heat

From measurements of the gas chromatographic retention volumes, the initial slopes of the adsorption isotherms of nitrogen and the simpler hydrocarbons on a series of steam-activated coconut charcoals were determined. The initial heats of adsorption were obtained in the usual way from the temperature dependence. It was found for all gases that both the initial slope of the isotherm and the initial heat of adsorption decreased with increasing degree of activation of the charcoal (i.e. with increasing surface area per g). This suggests that the higher affinity for the very small pores in less activated material more than counterbalances the lower total surface.Measurements at several different carrier gas flow rates of the relative band width for the charcoals of least and of greatest activation demonstrated, as might be expected, a greater resistance to mass transfer for the former. However, the apparent diffusion coefficients calculated on the assumption that all transport is by gas phase in the pores were nearly the same for each charcoal and showed relatively little variation among the different gases.

Baseline apparent diffusion coefficients: Validation study of new predictor of survival in patients with unresectable hepatocellular carcinoma following chemoembolization

2021 ◽  
pp. 1-10
Author(s):  
Lichao Xu ◽  
Shiqin Wang ◽  
Shengping Wang ◽  
Ying Wang ◽  
Wentao Li ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Roc Curve ◽  
Cox Regression ◽  
Response To Treatment ◽  
Roc Curve Analysis ◽  
Adc Value ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion ◽  
Response Biomarker ◽  
The Difference

OBJECTIVES: To investigate whether the baseline apparent diffusion coefficient (ADC) can predict survival in the hepatocellular carcinoma (HCC) patients receiving chemoembolization. MATERIALS AND METHODS: Diffusion-weighted MR imaging of HCC patients is performed within 2 weeks before chemoembolization. The ADC of the largest index lesion is recorded. Responses are assessed by mRECIST after the start of the second course of chemoembolization. Receiver operating characteristic (ROC) curve analysis is performed to evaluate the diagnostic performance and determine optimal cut-off values. Cox regression and Kaplan–Meier survival analyses are used to explore the differences in overall survival (OS) between the responders and non-responders. RESULTS: The difference is statistically significant in the baseline ADC between the responders and non-responders (P <  0.001). ROC analyses indicate that the baseline ADC value is a good predictor of response to treatment with an area under the ROC curve (AUC) of 0.744 and the optimal cut-off value of 1.22×10–3 mm2/s. The Cox regression model shows that the baseline ADC is an independent predictor of OS, with a 57.2% reduction in risk. CONCLUSION: An optimal baseline ADC value is a functional imaging response biomarker that has higher discriminatory power to predict tumor response and prolonged survival following chemoembolization in HCC patients.

scholarly journals On factors affecting surface free energy of carbon black for reinforcing rubber

2020 ◽  
Vol 9 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Shangyong Zhang ◽  
Ruipeng Zhong ◽  
Ruoyu Hong ◽  
David Hui
Keyword(s):  
Free Energy ◽  
Carbon Black ◽  
Surface Free Energy ◽  
Surface Activity ◽  
Gas Flow ◽  
Influential Factors ◽  
Chromatographic Column ◽  
Factors Affecting ◽  
Carrier Gas Flow

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

scholarly journals Classification of paediatric brain tumours by diffusion weighted imaging and machine learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jan Novak ◽  
Niloufar Zarinabad ◽  
Heather Rose ◽  
Theodoros Arvanitis ◽  
Lesley MacPherson ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Posterior Fossa ◽  
Brain Tumours ◽  
Diffusion Weighted Imaging ◽  
Regions Of Interest ◽  
Apparent Diffusion Coefficients ◽  
Diffusion Weighted ◽  
Apparent Diffusion ◽  
Paediatric Brain Tumours

AbstractTo determine if apparent diffusion coefficients (ADC) can discriminate between posterior fossa brain tumours on a multicentre basis. A total of 124 paediatric patients with posterior fossa tumours (including 55 Medulloblastomas, 36 Pilocytic Astrocytomas and 26 Ependymomas) were scanned using diffusion weighted imaging across 12 different hospitals using a total of 18 different scanners. Apparent diffusion coefficient maps were produced and histogram data was extracted from tumour regions of interest. Total histograms and histogram metrics (mean, variance, skew, kurtosis and 10th, 20th and 50th quantiles) were used as data input for classifiers with accuracy determined by tenfold cross validation. Mean ADC values from the tumour regions of interest differed between tumour types, (ANOVA P < 0.001). A cut off value for mean ADC between Ependymomas and Medulloblastomas was found to be of 0.984 × 10−3 mm2 s−1 with sensitivity 80.8% and specificity 80.0%. Overall classification for the ADC histogram metrics were 85% using Naïve Bayes and 84% for Random Forest classifiers. The most commonly occurring posterior fossa paediatric brain tumours can be classified using Apparent Diffusion Coefficient histogram values to a high accuracy on a multicentre basis.

scholarly journals Heterogeneity of Apparent Diffusion Coefficients Within Infarcts

Stroke ◽  
2001 ◽  
Vol 32 (7) ◽  
pp. 1695-1696
Author(s):  
Pratik Mukherjee ◽  
Robert C. McKinstry ◽  
Joshua S. Shimony ◽  
Erbil Akbudak ◽  
Abraham Z. Snyder ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion

Minimum apparent diffusion coefficients in the evaluation of brain tumors

2005 ◽  
Vol 55 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Omer Kitis ◽  
Hakan Altay ◽  
Cem Calli ◽  
Nilgun Yunten ◽  
Taner Akalin ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Diffusion Coefficients ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion

Cryochemical Modification of Medicinal Substances: The Effect of the Carrier Gas Flow Rate on the Physicochemical Properties of Nanoforms of the Antibacterial Drug Dioxidine

2021 ◽  
Vol 76 (3) ◽  
pp. 196-202
Author(s):  
T. I. Shabatina ◽  
Yu. N. Morozov ◽  
A. V. Solovyov ◽  
A. V. Shabatin ◽  
O. I. Vernaya ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Flow Rate ◽  
Gas Flow ◽  
Antibacterial Drug ◽  
Gas Flow Rate ◽  
Carrier Gas ◽  
Medicinal Substances ◽  
Carrier Gas Flow ◽  
Cryochemical Modification
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