The 2,2,3,3,3-pentafluoropropanol (PFP) monomer can exist in five conformations defined by the CCCO and CCOH dihedral angles: four mirror-imaged pairs (G+g+/G-g-, G+g-/G-g+, G+t/G-t, Tg+/Tg-) and an achiral Tt form. We examined the conformational landscape of the PFP⋅⋅⋅water complex using chirped pulsed Fourier transform microwave spectroscopy and theoretical calculations. Rotational spectra of two PFP⋅⋅⋅water conformers, PFPG+g+⋅⋅⋅W and PFPTg+⋅⋅⋅W , and seven deuterated isotopologues of each, were assigned. Tunneling splittings were observed for both conformers and are attributed to the exchange of the bonded and non-bonded hydrogen atoms of water. On the other hand, the tunneling splitting associated with the OH flipping motion in PFPTg+/Tg- appears to be quenched upon hydrogen bonding with water. The large amplitude motions associated with the water subunits were examined in detail to explain the very different magnitudes of the experimental and theoretical permanent electric dipole moment components. The study highlights the challenge in correctly identifying the conformers observed when large amplitude motions are involved. Quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analyses, as well as electrostatic potential (ESP) calculations were carried out to explore the nature of the non-covalent interactions and to appreciate the effects of fluorination.
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http://dx.doi.org/10.1002/cphc.202200348 | DOI Listing |
Sensors (Basel)
December 2024
Ophthalmic Instrumentation Development Lab, The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Wilmer 233, 600 N. Wolfe St., Baltimore, MD 21287, USA.
Signal amplitudes obtained from retinal scanning depend on numerous factors. Working with polarized light to interrogate the retina, large parts of which are birefringent, is even more prone to artifacts. This article demonstrates the necessity of using normalization when working with retinal birefringence scanning signals in polarization-sensitive ophthalmic instruments.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
College of Mechanical Engineering, Baoji University of Arts and Sciences, Baoji 721016, China.
The surface roughness of hole machining greatly influences the mechanical properties of parts, such as early fatigue failure and corrosion resistance. The boring and trepanning association (BTA) deep hole drilling with axial vibration assistance is a compound machining process of the tool cutting and the guide block extrusion. At the same time, the surface of the hole wall is also ironed by the axial large amplitude and low-frequency vibration of the guide block.
View Article and Find Full Text PDFChiropr Man Therap
January 2025
Karolinska Institutet Institute of Environmental Medicine, Nobels v. 13, 177 77, Stockholm, Sweden.
Objectives: To describe the structure and development of a new international, chiropractic, practice-based research network (PBRN), the Chiropractic International Research Collaborative (CIRCuit), as well as the demographic, practice, and clinical management characteristics of its clinician participants. An electronic survey was used to collect information on their demographics, practice, and clinical management characteristics from clinicians from 17 October through 28 November 2022. Descriptive statistics were used to report the results.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Glyn O. Phillips Hydrocolloid Research Centre, National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Industrial Microbiology in Hubei, Key Laboratory of Fermentation Engineering (Ministry of Education), Department of Bioengineering and Food Science, Hubei University of Technology, Wuhan 430068, China; Food Hydrocolloid International Science and Technology Cooperation Base of Hubei Province, Wuhan 430068, China. Electronic address:
Chitosan microgels (h-CSMs) were prepared by cross-linking hydrophobically modified chitosan with sodium phytate (SP). Emulsions stabilized by h-CSMs with different inter-phase fraction, microgel concentration and cross-linking density were studied of their microstructural and rheological properties. In particular, the large amplitude oscillatory shear (LAOS) of the high internal phase emulsions (HIPEs) stabilized by h-CSMs were systematically analyzed using the Fourier transform with Chebyshev polynomials (FTC) and sequence of physical processes (SPP) methods, to explore their nonlinear rheological properties.
View Article and Find Full Text PDFHum Reprod
January 2025
IRSD, Université de Toulouse, INSERM, INRAE, ENVT, Univ Toulouse III-Paul Sabatier (UPS), Toulouse, France.
Study Question: Does a human fallopian tube (HFT) organoid model offer a favourable apical environment for human sperm survival and motility?
Summary Answer: After differentiation, the apical compartment of a new HFT organoid model provides a favourable environment for sperm motility, which is better than commercial media.
What Is Known Already: HFTs are the site of major events that are crucial for achieving an ongoing pregnancy, such as gamete survival and competence, fertilization steps, and preimplantation embryo development. In order to better understand the tubal physiology and tubal factors involved in these reproductive functions, and to improve still suboptimal in vitro conditions for gamete preparation and embryo culture during IVF, we sought to develop an HFT organoid model from isolated adult stem cells to allow spermatozoa co-culture in the apical compartment.
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