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Denna studie undersöker den inbyggda piezomikrofonen i en akustisk gitarrs förmåga att tillsammans med en impulsrespons efterlikna ljudet från en kondensatormikrofon. Med hjälp av ett lyssningstest och 12 informanter undersöks skillnader som uppstår genom att spela in en akustisk gitarr med en kondensatormikrofon, piezomikrofon och piezomikrofon + impulsrespons. Resultatet visar att alla inspelningsmetoder har olika egenskaper, men att majoriteten uppskattar piezomikrofonen med impulsrespons mer än utan.

No / Cocrystal monohydrate of nitrofurantoin (NF) with melamine (MELA) has been studied as NF is an antibacterial drug used for the treatment of urinary tract infections. The structure of nitrofurantoin-melamine-monohydrate (NF-MELA-H2O) is characterized by FT-IR and FT-Raman spectroscopy. The energies and vibrational frequencies of the optimized structures calculated using quantum chemical calculations. Supported by normal coordinate analyses and potential energy distributions (PEDs), the complete vibrational assignments recommended for the observed fundamentals of cocrystal hydrate. With the aim of inclusion of all the H-bond interactions, dimer of NF-MELA-H2O has been studied as only two molecules of cocrystal hydrate are present in the unit cell. By the study of dimeric model consistent assignment of the FT-IR and FT-Raman spectrum obtained. H-bonds are of essential importance in an extensive range of molecular sciences. The vibrational analyses depict existence of H-bonding (O-H⋯N) between water O-H and pyridyl N atom of MELA in both monomer and dimer. To probe the strength and nature of H-bonding in monomer and dimer, topological parameters such as electron density (ρBCP), Laplacian of electron density (∇2ρBCP), total electron energy density (HBCP) and H-bond energy (EHB) at bond critical points (BCP) are evaluated by quantum theory of atoms in molecules (QTAIM). Natural bond orbitals (NBOs) analyses are carried out to study especially the intra and intermolecular H-bonding and their second order stabilization energy (E(2)). The value of HOMO-LUMO energy band gap for NF-MELA-H2O (monomer and dimer both) is less than NF, showing more chemical reactivity for NF-MELA-H2O. Chemical reactivity has been described with the assistance of electronic descriptors. Global electrophilicity index (ω = 7.3992 eV) shows that NF-MELA-H2O behaves as a strong electrophile than NF. The local reactivity descriptors analyses such as Fukui functions, local softnesses and electrophilicity indices performed to determine the reactive sites within NF-MELA-H2O. In MEP map of NF-MELA (monomer and dimer) electronegative regions are about NO2 and C=O group of NF, although the electropositive regions are around NH2, N-H group and H2O molecule. Molar refractivity (MR) value of NF-MELA-H2O (monomer and dimer) lies within the range set by Lipinski's modified rules. This study could set as an example to study the H-bond interactions in pharmaceutical cocrystals.

Yes / Literature solubilities and NMR and IR studies have been used to obtain properties or descriptors of edaravone. These show that edaravone has a significant hydrogen bond acidity so that it must exist in solution partly as the OH and NH forms, as found by Freyer et al. Descriptors have been assigned to the keto form which has a low hydrogen bond acidity, and which is the dominant form in nonpolar solvents. Physicochemical properties of the keto form can be been calculated such as solubilities in nonpolar solvents, partition coefficients from water to nonpolar solvents, and partition coefficients from air to biological phases.