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Other Hazards in Clinical NMR Examinations
Published in Bertil R. R. Persson, Freddy Ståhlberg, Health and Safety of Clinical NMR Examinations, 2019
Bertil R. R. Persson, Freddy Ståhlberg
The changing magnetic field caused the temperature of the solution around the prostheses to rise 0.3°C compared with the control which is quite insignificant. But relatively large temperature rises were recorded when both hip prostheses, together in saline, were exposed to Rf radiation. This is caused by the large conducting paths created when the two prostheses were in contact and surrounded by conducting solution. The Rf exposure caused the temperature of the solution around the prostheses to rise 2 to 6°C, depending on the orientation angle. These results suggest that individuals with large implants should not be imaged with NMR until further investigations are completed.
Chemistry and Isotopes of Iodine
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
The parameter to be established by paper chromatography is the retardation factor of a compound, commonly known as the Rf value. The Rf value is the mobility of a compound relative to that of the solvent front expressed as a fraction. For example, if the solvent front has moved 140 mm and the compound 70 mm, the Rf value is 0.5. For a given solvent system, the Rf is a characteristic of the compound, and it may be used, with precautions, for the preliminary identification of an unknown substance. The Rf values of many compunds are available in tables.31'32 Reproducibility of Rf values depends on the constancy of the following seven factors:35 paper, temperature, quantity of material applied, extraneous sub-stances, degree of saturation with water, supply of solvent, and distance between starting point and source of solvent.
Mathematical models of intraperitoneal drug delivery
Published in Wim P. Ceelen, Edward A. Levine, Intraperitoneal Cancer Therapy, 2015
Joanna Stachowska-Pietka, Jacek Waniewski
Note that changes in the tissue hydration may influence diffusive properties of the solute in the tissue, so in general, DS should be considered as θ or P dependent. Moreover, in some applications, parameter is called the sieving coefficient or the retardation factor as it represents the ratio of solute to solvent velocity, and in applications to solid tumor, is typically assumed to be equal to 1.
177Lu-doxycycline as potential radiopharmaceutical: electrochemical characterization, radiolabeling, and biodistribution in tumor-bearing mice
Published in International Journal of Radiation Biology, 2021
Zorana Milanović, Drina Janković, Sanja Vranješ-Đurić, Magdalena Radović, Željko Prijović, Gordana Zavišić, Marko Perić, Dalibor Stanković, Marija Mirković
A series of experiments were performed to define the optimal 177Lu-labeling conditions for the doxycycline ligand based on our previous experience (Aleksandar et al. 2020; Mirković et al. 2020). The labeling yield was determined by ascending paper and ITLC methods. The ITLC method with ammonia/methanol/water = 1:20:10 as the mobile phase, indicated that 177Lu-doxycycline complex migrated to the front of the SG plates (Rf = 0.9–1.0), while the free 177Lu stayed at the origin. The ascending paper chromatography on Whatman 3MM strips and saline as a mobile phase has not been shown as an appropriate method for determining radiochemical purity. Under optimized conditions, by radiolabeling of 10 mg of doxycycline hyclate with 177Lu (37 MBq) in a final volume of 1.0 ml (0.9% NaCl) at pH 6–7 and incubation at room temperature for 60 min, the radiochemical purity of 177Lu-doxycycline complex was 99%. When the labeling of the ligand with 177Lu was carried out at a higher temperature (60 °C) for a different time, it was observed that temperature and increased incubation time did not significantly affect the radiolabeling yield. The labeling of doxycycline was observed by the determination of one peak at the origin for 177LuCl3 (Figure 1(A)) and one at the solvent front for 177Lu-doxycycline (Figure 1(B)) on TLC chromatograms. Further radiolabeling verification was done by HPLC. It was noticed that the retention time of 177LuCl3 was 1.81 min and of 177Lu-doxycycline was 3.39 min (Figure 1(C)).
Evaluating the thermal performance of a balloon-based renal sympathetic denervation system with array electrodes: a finite element study
Published in Electromagnetic Biology and Medicine, 2021
Yanyan Cheng, Hongxing Liu, Zhen Tian, Meng Zhang, Youjun Liu, Qun Nan
The temperature distribution and lesion sizes were analyzed at different blood velocities. According to the results obtained, the temperature distribution at different flow conditions is almost the same (Figure 13). The difference in the lesion depth was not exceeded 0.5 mm. There was also a small difference in the lesion area (Figure 14). Berjano et al. (Gonzalez-Suarez and Berjano 2016) considered that the differences in the lesion depth were insignificant when the values were lower than 1 mm. An RF experimental study (Cao et al. 2010) considered that the differences in maximum temperature in the tissue or blood were considered to be insignificant for values lower than 4 °C. These results imply that the application of this device does not need to consider the difference in individual blood velocity.
A promising drug delivery candidate (CS-g-PMDA-CYS-fused gold nanoparticles) for inhibition of multidrug-resistant uropathogenic Serratia marcescens
Published in Drug Delivery, 2020
Ping Shi, Rajendran Amarnath Praphakar, Sadhasivan Deepa, Kannan Suganya, Prashant Gupta, Riaz Ullah, Ahmed Bari, Marudhamuthu Murugan, Mariappan Rajan
The crystallinity behavior of AuNPs/RF/INH/CS-g-PMDA-CYS NP was checked through XRD analysis. The crystalline nature of synthesized AuNPs was observed and shown in Figure S2. AuNPs displayed four different pattern at 2θ = 38.1, 44.3, 64.5, and 77.7. All the four pattern related to standard Bragg reflections (111), (200), (220), and (311) of face center cubic (fcc) cross-section (Krishnamurthy et al., 2014). The exceptional diffraction at 38.1 pattern shows that the favored development direction of zero-valent gold was fixed in (111) heading. The amorphous nature of CS-g-PMDA-CYS is shown in Figure S4. In the final XRD, the spectrum shows one broad pattern and the characteristic patterns of AuNPs (Figure S2). This indicates that the crystalline phase of RF and INH may reduce due to successful encapsulation.