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Single-Photon Emission Computed Tomography (SPECT) Imaging System and Quality Control
Published in Bhagwat D. Ahluwalia, Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
The gantry which is mounted rigidly on the floor, holds the camera head (or heads) and provides specific rotation around the patient. The camera head has a range of motion, inward to outward relative to the axis of rotation (AOR), so that the position of the camera face can be adjusted. The head can swivel about the rigid gantry arms so that the collimator angle to the organ can be adjusted. The gantry arm should be rigid and no sagging should occur at any angular location. Any sagging would cause shift and thus would result in shifting of the image relative to the AOR and would cause artifacts or produce unacceptable images.
Analysis of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Adriana Arigò, Mariosimone Zoccali, Danilo Sciarrone, Peter Q. Tranchida, Paola Dugo, Luigi Mondello
The measurement of optical rotation, [α]D20, either dextrorotatory or laevorotatory, is also widely recognized. Optical activity is determined by using a polarimeter, with the angle of rotation depending on a series of parameters, such as oil nature, the length of the column through which the light passes, the applied wavelength, and the temperature. The degree and direction of rotation are of great importance for purity assessments, since they are related to the structures and the concentration of chiral molecules in the sample. Each optically active substance has its own specific rotation, as defined in Biot's law: where α is the optical rotation at a temperature T expressed in degrees Celsius, l is the optical path length in dm, λ is the wavelength, and c is the concentration in g/100 mL. It is worthy of note that a standard 100 mm tube is commonly used; in cases in which darker or lighter colored oils are analyzed, longer or shorter tubes are used, respectively, and the rotation should be extrapolated for a 100 mm-long tube. Moreover, prior to the measurement, the essential oil should be dried out with anhydrous sodium sulfate and filtered.
Native Australian Plant Extracts: Cosmetic Applications
Published in Yasmina Sultanbawa, Fazal Sultanbawa, Australian Native Plants, 2017
The type of information required on plant preparations for cosmetics includes name of the plant, plant part used, type of extract and extraction solvent, purification/concentration, plus organoleptic characteristics, solubility, pH, loss on drying, ash, total solids, specific gravity, refraction index, specific rotation power and alcohol (or other solvent) content. Potential impurities, particularly in complex and concentrated plant extracts, may include pesticides, solvent residues, heavy metals and microbes, especially pathogenic bacteria.
Inhibition potential of phenolic constituents from the aerial parts of Tetrastigma hemsleyanum against soluble epoxide hydrolase and nitric oxide synthase
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Cai Yi Wang, Sunggun Lee, Hyun-Jae Jang, Xiang Dong Su, Heng-Shan Wang, Young Ho Kim, Seo Young Yang
The dried stems and leaves of T. hemsleyanum (25.0 kg) were extracted with 90% ethanol for 3 times (75 °C, 3h/time). All the filtrates were combined and concentrated to give a 1.0 kg crude extract. The crude extract was suspended in water and then respectively extracted 3 times with n-hexane, ethyl acetate and n-butanol by liquid − liquid separation. The ethyl acetate fraction (97.9 g) was further subjected to column chromatography over MCI resin, silica gel, RP-silica gel, Sephadex LH-20, and finally semipreparative RP-HPLC to obtain thirty-nine known compounds (see the process described as in Figure 2). The structures of compounds 1 − 39 were characterised by UV, 1H and 13 C NMR, ESI-MS data, and comparison with published spectroscopic data. The stereochemistry of chiral compounds was determined by comparing their specific rotation, NMR or CD spectra, respectively, with that in the literature (see Supporting information S1 and S2).
Chemical composition, enantiomeric analysis and anticholinesterase activity of Lepechinia betonicifolia essential oil from Ecuador
Published in Pharmaceutical Biology, 2022
James Calva, Luis Cartuche, Salomé González, José Vinicio Montesinos, Vladimir Morocho
The EO obtained through hydro distillation from the aerial parts of L. betonicifolia presented a yellow colour, a yield of 0.17 ± 0.03% (w/w) and a total volume of 16.5 g of EO from 9.85 kg of plant material. The density of EO was 0.87 ± 0.01 g/mL, the refractive index of 1.483 ± 0.01 and a specific rotation of c 11.45, CH2Cl2). The overall yield obtained for this plant was higher in comparison to the EO of L. heteromorpha with a value of 0.06% w/w as reported by Gilardoni et al. (2018), and much lower in comparison to L. paniculata with 0.49% w/w as reported by Panamito et al. (2021) and 0.317% w/w for L. mutica as reported by Ramírez et al. (2018).
Inhibition of Streptococcus mutans adhesion and biofilm formation with small-molecule inhibitors of sortase A from Juniperus chinensis
Published in Journal of Oral Microbiology, 2022
Eunji Cho, Ji-Yeon Hwang, Jae Sung Park, Daehyun Oh, Dong-Chan Oh, Hyeung-Geun Park, Jongheon Shin, Ki-Bong Oh
Compound 1 possessed two stereogenic centers at C-2 and C-3 of the lactone moiety. As extensively described in the literature [28,29], the non-equivalence of H2-4 (δH 4.03 and 3.83) assured the trans configuration between C-2 and C-3. Then, the absolute configurations were assigned as 2 R and 3 R based on comparison of its specific rotation ([α] −28.1) with those of (−)- and (+)-matairesinol ([α] and −47.2 and +15.2 for the (−) and (+) enantiomers, respectively) [30,31]. Thus, the structure of compound 1, designated 3’,3”-dihydroxy-(−)-matairesinol, was determined to be a novel 2,3-dibenzyl-4-butanolide lignan.