The effects of educational context on the understanding of linguistic concepts in english and isizulu by grade 7 learners

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Thermal Excitation of Gadolinium-Based Contrast Agents Using Spin Resonance.

Theoretical and experimental investigations into the thermal excitation of liquid paramagnetic contrast agents using the spin resonance relaxation mechanism are presented. The electronic spin-lattice relaxation time τ1e of gadolinium-based contrast agents, which is estimated at 0.1 ns, is ten orders of magnitude faster than the relaxation time of protons in water. The shorter relaxation time is found to significantly increase the rate of thermal energy deposition. To the authors' knowledge this is the first study of gadolinium based contrast agents in a liquid state used as thermal agents. Analysis shows that when τ1e and other experimental parameters are optimally selected, a maximum theoretical heating rate of 29.4 °C.s-1 could be achieved which would suffice for clinical thermal ablation of neoplasms. The experimental results show a statistically significant thermal response for two out of the four contrast agents tested. The results are compared to the simulated estimates via analysis of a detailed model of the system. While these experimentally determined temperature rises are small and thus of no clinical utility, their presence supports the theoretical analysis and strongly suggests that the chemical structure of the selected compounds plays an important role in this mechanism of heat deposition. There exists an opportunity for the development of alternative gadolinium-based compounds with an order of magnitude longer τ1e in a diluted form to be used as an efficient hyperthermia agent for clinical use

Steven Dinger, David Rubin and Peter Fridjhon, Thermal Excitation of Gadolinium-based Contrast Agents Using Spin Resonance, PLOS ONE Journal Data, 2016

The data contains the temperature results of the four tested gadolinium contrast agents: Magnevist, MultiHance, Dotarem and ProHance. As well as two control substances: distilled water and saline. The data also contains the decay and pulse response of ProHance.<br

Slope values <i>b</i>, with subscript definitions 1 = On/cOn and 2 = Off/cOff states, and comparison results performed on experimental datasets.

<p>Slope values <i>b</i>, with subscript definitions 1 = On/cOn and 2 = Off/cOff states, and comparison results performed on experimental datasets.</p

Model estimates for Dotarem and ProHance treatment-control condition responses.

<p>Model estimates for Dotarem and ProHance treatment-control condition responses.</p

Model parameters used to fit the pulse and decay responses of the ProHance solution.

<p>Model parameters used to fit the pulse and decay responses of the ProHance solution.</p

Mean temperature rise over a ninety second interval for the six tested substances, with each mean value obtained over thirty experiments and a linear regression line fitted.

<p>Standard error bars shown at every 8 s.</p

Experimental values used to calculate the spin-power and resulting temperature rate, with the electronic spin relaxation times <i>τ</i>_1<i>e</i> and <i>τ</i>_2<i>e</i> obtained from Rast and Atsarkin [12, 13].

<p>Experimental values used to calculate the spin-power and resulting temperature rate, with the electronic spin relaxation times <i>τ</i>_1<i>e</i> and <i>τ</i>_2<i>e</i> obtained from Rast and Atsarkin [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158194#pone.0158194.ref012" target="_blank">12</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158194#pone.0158194.ref013" target="_blank">13</a>].</p

System block diagram of experimental setup.

<p>System block diagram of experimental setup.</p

Experimental and model estimate for the specific heat capacity of ProHance using the average of the pulse (<i>C</i>_Δ) and decay (<i>C</i>_<i>d</i>) response.

<p>Experimental and model estimate for the specific heat capacity of ProHance using the average of the pulse (<i>C</i>_Δ) and decay (<i>C</i>_<i>d</i>) response.</p