The diagnosis of early-stage lung cancer is challenging due to its asymptomatic nature, especially given the repeated radiation exposure and high cost of computed tomography(CT). Examining the lung CT images to detect pulmonary nodules, especially the cell lung cancer lesions, is also tedious and prone to errors even by a specialist. This study proposes a cancer diagnostic model based on a deep learning-enabled support vector machine (SVM). The proposed computer-aided design (CAD) model identifies the physiological and pathological changes in the soft tissues of the cross-section in lung cancer lesions. The model is first trained to recognize lung cancer by measuring and comparing the selected profile values in CT images obtained from patients and control patients at their diagnosis. Then, the model is tested and validated using the CT scans of both patients and control patients that are not shown in the training phase. The study investigates 888 annotated CT scans from the publicly available LIDC/IDRI database. The proposed deep learning-assisted SVM-based model yields 94% accuracy for pulmonary nodule detection representing early-stage lung cancer. It is found superior to other existing methods including complex deep learning, simple machine learning, and the hybrid techniques used on lung CT images for nodule detection. Experimental results demonstrate that the proposed approach can greatly assist radiologists in detecting early lung cancer and facilitating the timely management of patients.

Sulfonated membranes from highly aromatic copoly(ether–amide)s with sulfonation degrees (SDs) between 20 mol% and 55 mol% were prepared from the combination of diamines, 4,4′-(hexafluoroisopropylidene)-bis-( p-phenyleneoxy)dianiline (HFD), and different molar concentrations of 2,4-diaminobenzenesulfonic acid (DABS) that were reacted with equimolar amounts of isophthalic acid (ISO). The ionic membranes show–SO₃H groups in the expected concentrations as assessed by Fourier transform infrared and proton nuclear magnetic resonance. Sulfonated copoly(ether–amide) membranes show the first thermal decomposition at 281°C for the sulfonic moieties and a second thermal loss at 439°C for the rigid nonsulfonated backbone which imparts them their high thermal stability. The ion-exchange capacity and water absorption in the sulfonated copoly(ether–amide)s increase steadily with SD. The copoly(ether–amide) with the larger SD, 55 mol% of DABS, HFD- co-ISO/DABS-55, shows the highest proton conductivity (91 mS cm⁻¹) at 75°C. These results situate HFD- co-ISO/DABS-55 as a possible electrolyte membrane for use in polymer electrolyte membrane fuel cell with high thermal and mechanical stability.

Seven aromatic polyamides and copolyamides were synthesized from two different aromatic diamines: 4,4′-(Hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline (HFDA) and 2,4-Aminobenzenesulfonic acid (DABS). The synthesis was carried out by polycondensation using isophthaloyl dichloride (1SO). The effect of an increasing molar concentration of the sulfonated groups, from DABS, in the copolymer properties was evaluated. Inherent viscosity tests were carried out to estimate molecular weights. Mechanical tests were carried out under tension, maximum strength ( $\mathsf{\sigma }$ _max), Young’s modulus (E), and elongation at break (ε_max) to determine their mechanical properties. Tests for water sorption and ion exchange capacity (IEC) were carried out. Proton conductivity was measured using electrochemical impedance spectroscopy (EIS). The results indicate that as the degree of sulfonation increase, the greater the proton conductivity. The results obtained showed conductivity values lower than the commercial membrane Nafion 115 of 0.0065 S cm⁻¹. The membrane from copolyamide HFDA/DABS/1S0-70/30 with 30 mol DABS obtained the best IEC, with a value of 0.747 mmol g⁻¹ that resulted in a conductivity of 2.7018 × 10⁻⁴ S cm⁻¹, lower than the data reported for the commercial membrane Nafion 115. According to the results obtained, we can suggest that further developments increasing IEC will render membranes based on aromatic polyamides that are suitable for their use in PEM fuel cells.

Several aromatic sulfonated copoly(ether–amide)s, based on the aromatic diamines 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)-dianiline (HFD) and 2,4-diaminobenzensulfonic acid (DABS) and 4,4′-oxybis(benzoic acid) (OBA), were synthesized through a polycondensation reaction. The sulfonation degree was controlled by introducing different concentrations of 2,4-DABS from 40 mol% up to 80 mol%. Proton nuclear magnetic resonance validated the expected concentrations of sulfonic acid groups in the sulfonated aromatic copoly(ether–amide)s. Thermal decomposition of sulfonic groups was found to initiate at 280°C, while main chain decomposition initiates at 410°C. Proton conductivity between 30°C and 75°C was 19.0 and 45.0 mS/cm, respectively, for the copolymer with the highest concentration of sulfonic groups (–SO₃H). Comparison with structurally similar sulfonated copolyamides and copoly(ether–amide)s indicates that these new sulfonated copoly(ether–amide)s based on 4,4′-OBA show improved mechanical properties, but a decrease in ion exchange capacity and proton conductivity.

In the present study the effect that controlled structural modifications have on the physical and conformational properties of a series of isomeric aromatic polyamides synthesized with different bulky pendant lateral groups was investigated. Physical properties of the aromatic polyamides such as thermal properties were determined by differential scanning calorimetry. Structural changes were determined by Fourier transform infrared spectroscopy, density and fractional free volume ( FFV). Light scattering and dynamic-mechanical analysis were used to characterize the thermodynamic and kinetic rigidity. Vogel's model was applied to evaluate kinetic rigidity in polyamide chains and the results were compared with physical properties data. It was found that there was a relationship between T_g and the conformational entropy determined by the structure which indicates that the higher the level of rigidity in the polyamide the higher the value of T_g. For kinetic rigidity, it was found that the relaxation time at infinite temperature B_α , was very close to the value 5 x 10^-12 s, reported for other amorphous glassy materials. There was also a relationship between the activation energy of the glass transition U_∞ and FFV, which is determined by the presence or absence of the bulky functional groups, indicating that the smaller the FFV, the higher the energy required for the glass transition to take place.