Comparison of the properties of phenolic resin synthesized from different aldehydes and evaluation of the release and health risks of VOCs.

Different amounts of glyoxal and paraformaldehyde were used to synthesize phenol-glyoxal (PG) and phenol-paraformaldehyde (PPF) resins, which were compared with conventional phenol-formaldehyde (PF) resins. Glyoxal oxidation leads to a pH value of 9.83 for PG 2.2. With the addition of polyformaldehyde, PPF 2.2 exhibited the highest viscosity at 17333.33 mPa s. The PPF 2.0 plywood has a maximum bonding strength of 1.94 MPa. The formaldehyde emission of PG 1.8 plywood is found to have a minimum value of 0.025 mg/m3, reaching the ENF limit (≤0.025 mg/m3). Acetaldehyde is found only in volatile organic compound (VOC) emissions from PG plywood and is associated with increased glyoxal. PPF plywood emitted more aromatic and total VOC (TVOC) than the other two plywood types. The measured TVOC for PPF 2.2 is 196.07 µg/m3. The results showed that the total cancer risk (TCR) values of PPF 1.8, PPF 2.0, and PG 1.8 were above the threshold of 1.00E-4, indicating a definite carcinogenic risk. Acetaldehyde in the PG plywood exceeded the safety threshold for noncarcinogenic risk. The use of paraformaldehyde in the wood-based panel production is been considered a possible means of improving the bonding strength of plywood. Glyoxal has also been shown to be a viable method for lowering the formaldehyde emissions from plywood. The VOC emissions from plywood changed significantly depending on the aldehyde used. Limiting VOCs that present high health hazards is crucial for reducing the negative impact of plywood on both indoor environments and human health.

Association between glymphatic dysfunction and neurocognitive decline in patients with frontal lobe epilepsy.

Background: The glymphatic system is essential for the maintenance of brain homeostasis. It may be impaired in patients with epilepsy, but its association with neurocognitive function remains unknown. In this study, we aimed to elucidate the association between changes in the glymphatic system and neurocognitive function in individuals diagnosed with frontal lobe epilepsy (FLE). Methods: This retrospective case-control research engaged a group of patients with FLE and age-, sex-, and education-matched healthy volunteers. All participants were subjected to extensive neurocognitive assessments, complemented by structural and diffusion-weighted imaging. The "diffusion tensor imaging analysis along the perivascular space" (DTI-ALPS) index was computed to ascertain differences in glymphatic system function between the groups. Univariate and multivariate analyses were conducted to explore associations between DTI-ALPS, clinical characteristics in patients with FLE, and the neurocognitive test outcomes for both groups. Results: Twenty-five patients [mean age ± standard deviation (SD): 26.28±8.12 years, 10 females] with FLE and 22 healthy control (HC) participants (average age ± SD: 25.86±6.15 years, 11 females) were included. The average ALPS-index in FLE group was significantly lower than that in HC group (1.387±0.127 vs. 1.468±0.114, P=0.026). Further, significant neurocognitive difference was noted in Trail Making Test (TMT), Stroop Color and Word Test (SCWT), Digit Span Test (DST) and similarity test (ST) between the two groups. ALPS-index scores exhibited a negative correlation with disease duration in patients with FLE (r=-0.415, P=0.039), and positive correlations with the Forward Digit Span Test (FDST, r=0.399, P=0.005) and Similarity Test (ST, r=0.395, P=0.006) in both groups. After adjusting for potential confounders, DTI-ALPS maintained a significant independent association with FDST and ST. Conclusions: The findings of the current study suggest a possible association between impairment in glymphatic function and FLE. Furthermore, results indicate that glymphatic dysfunction, as assessed via DTI-ALPS index, appears to be related to neurocognitive decline in FLE.

Topological abnormality of structural covariance network in MRI-negative frontal lobe epilepsy.

Background: Frontal lobe epilepsy (FLE) is the second most common type of focal epilepsy, however, imaging studies of FLE have been far less than Temporal lobe epilepsy (TLE) and the structural findings were not consistent in previous literature. Object: Investigate the changes in cortical thickness in patients with FLE and the alteration of the structural covariance networks (SCNs) of cortical thickness with graph-theory. Method: Thirty patients with FLE (18 males/12 females; 28.33 ± 11.81 years) and 27 demographically matched controls (15 males/12 females; 29.22 ± 9.73 years) were included in this study with high-resolution structural brain MRI scans. The cortical thickness was calculated, and structural covariance network (SCN) of cortical thickness were reconstructed using 68 × 68 matrix and analyzed with graph-theory approach. Result: Cortical thickness was not significantly different between two groups, but path length and node betweenness were significantly increased in patients with FLE, and the regional network alterations were significantly changed in right precentral gyrus and right temporal pole (FDR corrected, p < 0.05). Comparing to HC group, network hubs were decreased and shifted away from frontal lobe. Conclusion: The topological properties of cortical thickness covariance network were significantly altered in patients with FLE, even without obvious surface-based morphological damage. Graph-theory based SCN analysis may provide sensitive neuroanatomical biomarkers for FLE.