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The Metabolic Cart
Published in Michael M. Rothkopf, Jennifer C. Johnson, Optimizing Metabolic Status for the Hospitalized Patient, 2023
Michael M. Rothkopf, Jennifer C. Johnson
Glucose, with its six oxygen atoms (one for every carbon atom), produces the same amount of molar CO2 as the amount of O2 it consumes in oxidation. The oxidation formula looks like this: C6H12O6 + 6O2 → 6CO2 + 6H2O. In this example, the oxygen consumed and CO2 produced are 6 moles each. Therefore, the numerator and denominator are 6/6, yielding an RQ of 1.0. If the patient’s RQ is in this range, the predominant metabolic pattern is carbohydrate utilization.
Radiometry
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Organic scintillators usually contain aromatic carbon compounds, consisting of carbon and hydrogen. In these compounds, the carbon atoms form benzene rings, each containing six carbon atoms and a carbon atom in the ring is thus bound to two carbon atoms and one hydrogen atom. This molecule is planar, that is, the orbitals of the bound electrons all lie in the same plane with a bond angle of 120°. However, one of the electrons in the carbon L-shell does not take part in the bonds, and these six electrons form orbitals that are orthogonal to the molecular plane. These π-electrons make it possible for the benzene molecule to bind to another benzene molecule. Absorption of energy may cause excitation of a π-electron, followed by emission of light upon de-excitation.
Structure of Matter
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
Unified atomic mass unit: As seen previously, the mass of a given atom is close to the sum of the masses of the nucleons and the electrons. Remember that the mass of an electron is about 1840 times smaller than the mass of a nuclear particle. The actual mass of an atom, expressed in terms of kilograms, the usual international unit of mass, is very small and not of much practical use. Consequently, another approach is often used: defining a special unit of atomic mass (symbol u).* The atomic mass unit was defined to be approximately the mass of a nuclear particle, permitting the atomic mass of an atom to be expressed with numbers close to the mass number. The official definition of the unified atomic mass unit is related to 1/12 of the mass of the carbon atom with six protons and six neutrons, i.e. 1 u ≈ 1.661 × 10−27 kg. Because the mass of a carbon atom is exactly 12 u, expressed with this unit, it is strictly equal to its mass number. However, the mass of an atom of oxygen 16, for example, is 15.9991 u, which is slightly different from its mass number.
Dyhidro-β-agarofurans natural and synthetic as acetylcholinesterase and COX inhibitors: interaction with the peripheral anionic site (AChE-PAS), and anti-inflammatory potentials
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Julio Alarcón-Enos, Evelyn Muñoz-Núñez, Margarita Gutiérrez, Soledad Quiroz-Carreño, Edgar Pastene-Navarrete, Carlos Céspedes Acuña
Spectral data of compound 4 indicates that this has an OH group at the C-4 position, which was confirmed by a singlet at δ 1.32 ppm in the 1H NMR spectrum and a quaternary carbon atom at δ 76.29 ppm in the 13 C NMR. The H-3 coupling, attached to the C-3 carbon, is seen as two double signals with an average shift of 3.58 (J= 5.1; 10.1 Hz) accounting for an axial proton at this centre. The methyl group at C-4 is in the equatorial position because it showed strong NOEs with H-3 and with the equatorial H-6, while the axial H-6 displayed NOE with the methyl group at C-10 (Figure 2). The 13 C NMR and DEPT (Distortionless Enhancement by Polarisation Transfer) spectra in combination with HSQC data indicate that compound 4 has an agarofuran skeleton with 15 carbons, including four methyl carbons at δ C 22.79 ppm (C-12), 21.56 ppm (C-13), 23.79 ppm (C-14), and 30.50 ppm (C-15), five methylene carbons at δ C 24.35 ppm (C-1), 32.39 ppm (C-2), 35.41 ppm (C-6), 26.59 ppm (C-8) and 37.55 ppm (C-9), two methine carbons at δ C 73.53 ppm (C-3) and 43.68 ppm (C-7), and four quaternary carbons at δ C 76.29 ppm (C-4), 88.50 ppm (C-5), 38.33 ppm (C-10), and 82.44 ppm (C-11). Esterification of compound 4 with acetic anhydride yields compound 5. 1H NMR of this compounds shows an additional methyl at 2.07 ppm, corresponding to methyl acetate. The position of the acetate group was further confirmed by the HMBC (heteronuclear multiple bond correlation) correlations of H-3 (δ 4.86 ppm) with carbonyl at δ170.50 ppm.
Microencapsulation of reactive isocyanates for application in self-healing materials: a review
Published in Journal of Microencapsulation, 2021
Amanda N. B. Santos, Demetrio J. dos Santos, Danilo J. Carastan
The term “isocyanate” may refer to the chemical group with formula R-N=C=O, but it is also the generic name of the chemical compounds which have one or more –NCO groups in their structure. The carbon atom in these compounds has an electropositive charge, making it extremely reactive with chemical groups which have an active atom of hydrogen (nucleophilic reagent), such as alcohols, amines and water. The reaction of NCO with the mentioned chemical groups usually forms urethane or urea bonds (Sharmin and Zafar 2012, Cherng et al.2013, Gogoi et al.2014). NCO is available in a large number of chemical compounds with a wide range of reactivity levels. They are usually classified as aliphatic, such as isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and 4,4′-bis-methylene cyclohexane diisocyanate (HMDI), or aromatic, such as toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI) and polyaryl polymethylene isocyanate (PAPI). The chemical structure of these isocyanates is presented in Figure 2. These compounds are usually combined with other monomers to form polymeric materials covering a vast array of properties, more often based on urethane and urea bonds.
Potential anti-neuroinflammatory NF-кB inhibitors based on 3,4-dihydronaphthalen-1(2H)-one derivatives
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Yue Sun, Yan-Qiu Zhou, Yin-Kai Liu, Hong-Qin Zhang, Gui-Ge Hou, Qing-Guo Meng, Yun Hou
The structures of 6a-n were characterised by NMR and MS (Supporting Information). Some selected spectral data are discussed below. In the 1H NMR spectra of our target compounds, the chemical shifts in the range of 7.89–7.65 ppm appear as a singlet attributed to the proton of α,β-unsaturated ketone pharmacophores. All compounds showed two groups of characteristic triplets from the two intra-annular methylene groups at δ 3.16–2.81 ppm. The singlets observed in the range of 5.21–5.09 ppm are likely the three protons of 7-methoxy in 3,4-dihydronaphthalen-1(2H)-one. In the 13C NMR spectra, the carbon atom of -C=O groups appeared in chemical shifts of approximately 187 ppm. Additionally, HRMS spectroscopy data further confirmed the accuracy of the structures of these compounds. In order to investigate the influence of the length of the substituent of 3,4-dihydronaphthalen-1(2H)-one derivatives on neuroinflammation, several benzyloxy-substituted arylaldehydes were selected to synthesise novel 3,4-dihydronaphthalen-1(2H)-one derivatives (7a-c). The yields of 7a-c reached approximately 76–79%. All analyses showed the same results as described with 6a-n, with the exception of additional singlets observed in the range of 5.21–5.09 ppm of the 1H NMR spectra of 7a-c, corresponding to two methylene protons in the benzyloxy group. Corresponding NMR and HRMS data are shown in Supporting Information, which further confirm the accuracy of their structures.