Figure 1:
![Raw dielectric constant spectra as a function of frequency for 6 GABA concentrations investigated. 100 spectra for each of the concentrations. From [13], with permission.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721ec0215d2f6c89dbc9a8/j_joeb-2023-0006_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251208%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251208T103621Z&X-Amz-Expires=3600&X-Amz-Signature=25ff4ce048109229745ec42f360f9858f47c5e8b34f7e8210917800733bad728&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 2:
![Water contribution subtracted dielectric constant spectra, as a function of frequency for 6 GABA concentrations. The average of 100 measurements of the water dielectric constant spectrum was subtracted from each of the GABA solution measurements. From [13], with permission.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721ec0215d2f6c89dbc9a8/j_joeb-2023-0006_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251208%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251208T103621Z&X-Amz-Expires=3600&X-Amz-Signature=595747fec92095fd186b5e797b0994dc4f3981647b34aee24aa575b70a6d3846&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 3:
![Principal component analysis on six different GABA concentrations. The X-axis shows the first component which covers 81.8% of the variance in the dataset, the Y-axis shows the second component which covers 10.4% of the variance in the dataset. From [13], with permission.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721ec0215d2f6c89dbc9a8/j_joeb-2023-0006_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251208%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251208T103621Z&X-Amz-Expires=3600&X-Amz-Signature=00a61f73385734399558ea229adff8e4967c54ef3cf6ca043103adc101984a3e&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
LSTM model results on a dataset consisting of six different GABA concentrations_ “Raw data” means unprocessed dielectric constant data obtained from the GABA solution measurements_ “Subtracted data” implies that the experimental dielectric constant of water (data averaged over 100 measurements) was subtracted from each of the dielectric constant data for the GABA solutions_ From [13], with permission_
| Test Accuracy | Test Loss | |
|---|---|---|
| Raw data | 0.90164 | 0.39048 |
| Subtracted data | 0.99167 | 0.01064 |
Performance of the LSTM neural network_ Raw ϵ′ data is the measured dielectric constant data of GABA solutions, whereas the subtracted ϵ′ data is the difference between the measured dielectric constant data of the GABA solutions and the average dielectric constant data of deionized water_ From [13], with permission_
| Raw ϵ′ data | Subtracted ϵ′ data | |||
|---|---|---|---|---|
| c [μm] | Test dataset Accuracy | Test dataset Loss | Test dataset Accuracy | Test dataset Loss |
| 5 vs 10 | 1.0 | 0.00609 | 1.0 | 0.00007 |
| 10 vs 20 | 1.0 | 0.00449 | 1.0 | 0.00004 |
| 20 vs 50 | 1.0 | 0.00139 | 1.0 | 0.00009 |
| 50 vs 100 | 1.0 | 0.06400 | 1.0 | 0.00270 |
| 100 vs 200 | 1.0 | 0.08303 | 1.0 | 0.00204 |