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Accurate Analytical Solutions of Fractional Nonlinear Oscillator Systems with Matching Approach
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Structure–activity and structure–property relationships in CARBAZOLE-based AZETIDIN-2-one: Synthesis, antimicrobial evaluation, DFT, docking, ADME, and toxicity studies
No full textIn response to the increasing global threat of antimicrobial resistance and the reduced efficacy of current antibiotics, this study reports the synthesis, structural characterization, and combined experimental and computational evaluation of 12 novel carbazole-based 2-azetidinone derivatives (5a–f and 6a–f) for their antimicrobial activities. The compounds were synthesized using conventional, ultrasonic, and microwave-assisted methods, with microwave irradiation giving yields up to 98.6% within only 5 min. Biological evaluations identified compounds 5b, 5e, 6b, and 6e as active carbazole-based β-lactams. Compounds 6b and 6e showed activity against Escherichia coli (25.3 and 24.1 mm) and Pseudomonas aeruginosa (23.0 and 22.0 mm), outperforming streptomycin (20.8 and 20.3 mm), with MICs of 78 faecalis (22.9 mm, MIC 78 μ μ g/mL. For Gram-positive strains, 6b inhibited Enterococcus g/mL), while Staphylococcus aureus suppressed by 6b (MIC 78 (MIC 312 μ μ g/mL) and 5e/6e g/mL). In antifungal assays, compound 6e showed remarkable activity against Candida albicans, producing a 28.4 mm inhibition zone and an MIC of 78 μ also effective against Aspergillus brasiliensis (MIC 78 μ g/mL, comparable to fluconazole (26.0 mm), and was g/mL). Density functional theory analyses revealed that compounds 5e and 6e display the smallest HOMO–LUMO gaps and the highest global electrophilicity indices. Molecular docking confirmed their superior binding affinities toward β-lactamase and penicillin-binding protein targets, with energies of 10.5 to 11.6 kcal/mol. ADME predictions indicated favorable drug-likeness and high gastrointestinal absorption. Overall, experimental and theoretical findings highlight compounds 5b, 5e, 6b, and 6e as promising leads for antimicrobial drug development and preclinical evaluation.</p
Functional hyper-crosslinked polymers as advanced materials for hydrogen generation via sodium borohydride methanolysis
No full textAir pollution caused by fossil fuels is the biggest problem humanity has ever created, and clean energy sources like hydrogen are seriously needed to solve it. Therefore, in this study, four phenanthrene-based hyper-crosslinked polymers (PTHCP-1–4) were synthesized via Friedel–Crafts alkylation and characterized by FTIR, BET, SEM, XPS, TGA, and zeta potential measurements. The BET surface areas ranged from 518.9 to 908.8 m2 g-1, with PTHCP-4 showing the highest value, while pore volumes varied between 0.24 and 1.60 cm3 g-1. SEM revealed uniform nanoscale particles for PTHCP-2 (mean size 54 nm) and aggregated morphologies for PTHCP-3/4. XPS confirmed incorporation of pyridinic-N (399.3 eV) and phenolic –OH groups, and TGA demonstrated high thermal stability with main degradation above 400 °C. Zeta potentials shifted from +36.3 mV (PTHCP-3) or −6.48 mV (PTHCP-1) to more negative values after reaction, indicating surface interaction with BH4- species. Catalytic tests showed hydrogen generation rates (HGR) up to 34600 mL H2 min-1 gcat-1 (PTHCP-3) with the lowest activation energy (27.22 kJ mol-1). PTHCP-4 retained 95 % of its activity after five cycles, confirming excellent reusability. These results highlight the synergy between surface area, pore structure, and heteroatom functionality in optimizing metal-free catalysts for NaBH4 methanolysis
Prognostic Factors of Late-onset Hearing Loss in Infants With Congenital Cytomegalovirus and Normal Audiologic Assessment at Birth
No full textBackground and aims: Children with congenital cytomegalovirus (cCMV) can develop late-onset sensorineural hearing loss (LO-SNHL). In this study, we aim to assess the characteristics and predictors of LO-SNHL in infants with cCMV having normal hearing at the first neonatal assessment. Methods: A retrospective study within the European Registry of Children with cCMV (www.ccmvnet.org) was performed. Included children had cCMV and a normal first audiological assessment by Auditory Brainstem Response (ABR). Late-onset hearing loss (LO-SNHL) is defined as the presence of sensorineural hearing loss after an initial normal hearing test. Hearing evaluation was performed at birth, at 6 months of age, and at least annually up to 6 years of age. Results: Seven hundred twenty-one children with normal audiological tests at birth were included, and 47/721 (6.5%) developed LO-SNHL. LO-SNHL was diagnosed at a range of 4-65 months of age [median (IQR) age: 34.3 (15.1-48.7) months]. Children with LO-SNHL had a higher proportion of abnormalities on physical examination at birth (45.7% vs. 20.8%; P < 0.001): petechiae (17.4% vs. 6.0%; P = 0.008), splenomegaly (8.7% vs. 2.3%; P = 0.031), hepatomegaly (13% vs. 2.9%; P = 0.001), microcephaly (15.2% vs. 4.5%; P = 0.005) and small for gestational age (21.7% vs. 8.3% P = 0.005). Children with LO-SNHL showed lower platelet count at birth [177500.0 (88750.0-261250.0)/μL vs. 243500.0 (173000.0-304000.0)/μL; P = 0.012], and higher blood viral load at birth [3.7 log (3.3-4.4) vs. 3.4 log (2.7-3.9) IU/mL; P = 0.013] and had more frequent white matter involvement (27.7% vs. 14.7%; P = 0.03) and ventriculomegaly (20.7% vs. 4.6%; P = 0.001) on birth magnetic resonance imaging. Overall, symptomatic children at birth showed a higher risk of developing LO-SNHL than asymptomatic children (32/317, 10.1%, vs. 15/404, 3.7%; P < 0.0001). Among asymptomatic children, only 0.3% developed severe or profound LO-SNHL in the best ear. In multivariate logistic regression analysis, ventriculomegaly [odds ratio (OR): 7.503 (1.78-27.9)], white matter abnormalities [OR: 3.19 (1.010-9.01)], and splenomegaly [OR: 3.679 (1.56-8.506)] at birth were associated with the development of LO-SNHL (Fig. 1). Conclusions: Among this large cohort of children with cCMV and a first normal audiological assessment, the risk of LO-SNHL was 6.5%. Asymptomatic children developed LO-SNHL in 3.7% of the cases versus 10.1% in symptomatic cases. In multivariate logistic regression analysis, ventriculomegaly, white matter abnormality, and splenomegaly at birth were associated with LO-SNHL
