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A reactant used globally in the production of polyurethane is the molecule 4,4'-methylene diphenyl diisocyanate (4,4'-MDI). The structural flexibility of 4,4'-MDI is one of the most important molecular properties influencing the polymerization process and this property was therefore modeled using density functional theory (DFT) calculations and Car-Parrinello molecular dynamics (MD) simulations. Global and local minima structures were found and confirmed by vibrational analysis. The energy barriers related to rotation of the aromatic rings were estimated by DFT calculations. The stability of global and local minima was verified by Car-Parrinello (MD) runs at finite temperature. The presence of weak C-H⋯π hydrogen bonds was confirmed by atoms in molecules analysis and found to be responsible for the low energy barriers.
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http://dx.doi.org/10.1007/s00894-014-2097-8 | DOI Listing |
Phys Chem Chem Phys
September 2025
School of Electrical and Automation Engineering, Suzhou University of Technology, Suzhou, 215506, China.
A flexible bipolarization conversion metasurface based on graphene is proposed in this paper, which can achieve single-band linear-to-linear (LTL) and dual-band linear-to-circular (LTC) polarization conversion. The polarization conversion ratio (PCR) and axial ratio (AR) are dynamically regulated by varying the sheet resistance () of graphene. When = 1400 Ω Sq, the designed metasurface achieves a single-band LTL polarization conversion of 7.
View Article and Find Full Text PDFACS Nano
September 2025
School of Nano-Tech and Nano Bionics, University of Science and Technology of China, Hefei 230000, China.
Structural colors offer distinct advantages over traditional chemical colors (such as pigments and dyes), including high saturation, resistance to fading, and environmental friendliness. However, unlike traditional dyes or pigments that allow for Structural colors offer distinct advantages over traditional chemical colors (such as pigments and dyes), including high saturation, resistance to fading, and environmental friendliness. However, unlike traditional dyes or pigments that allow for arbitrary color adjustments during the coloring process, current structural color surfaces lack flexibility in control, as their colors are difficult to reprocess or adjust once formed.
View Article and Find Full Text PDFChemSusChem
September 2025
Stokes Laboratories, School of Engineering, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland.
The development of mechanically robust, biocompatible, and biodegradable hydrogels remains a significant challenge for biomedical applications involving load-bearing soft tissues. Herein, a tubular lignin-derived hydrogel is engineered to assess its physicochemical, mechanical, and biological properties. Kraft and organosolv lignin are systematically compared at varying crosslinker concentrations to determine their effect on pore morphology, swelling behavior, and mechanical performance.
View Article and Find Full Text PDFMol Plant
September 2025
Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, P. R. China; MOE Key Laboratory of Gene Function and Regulation, Sun Yat-sen University, Guangzhou 510275, P. R. China. Electronic address:
Long noncoding RNAs (lncRNAs) are emerging as pivotal regulators in gene expression networks, characterized by their structural flexibility and functional versatility. In plants, lncRNAs have gained increasing attention due to accumulating evidence of their roles in modulating developmental plasticity and agronomic traits. In this review, we focus on the origin, classification, and mechanisms of action of plant lncRNAs, with a particular emphasis on their involvement in developmental processes.
View Article and Find Full Text PDFJ Behav Health Serv Res
September 2025
Department of Counselor Education, Fairfield University, Fairfield, CT, USA.
This qualitative study explores what factors influence teaming in behavioral health settings, from the perspective of behavioral health providers. Twenty-four participants from a range of behavioral health professions engaged in semi-structured interviews. Using a grounded theory approach, data were analyzed, and a "prism" model was developed to capture the complexities of behavioral health providers' perceptions of factors influencing teaming in various mental health and/or substance use disorder treatment programs.
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