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Suprapectoral biceps tenodesis
Published in Andreas B. Imhoff, Jonathan B. Ticker, Augustus D. Mazzocca, Andreas Voss, Atlas of Advanced Shoulder Arthroscopy, 2017
Magnetic resonance imaging is the radiologic study of choice because it can accurately diagnose concomitant conditions such as rotator cuff tears and SLAP lesions. However, because of the angulation of the LHB in the rotator interval, magic angle artifact can spuriously increase tendon signal on MRI in this location, limiting assessment.21–23 This further highlights the importance of a thorough physical examination.
Instrumentation
Published in Clive R. Bagshaw, Biomolecular Kinetics, 2017
Electric-field jumps perturb the system by “physical” and “chemical” means. Molecules may transiently align with the field due to their net dipole moment. The electric field also perturbs the degree of ionization of weak electrolytes and therefore shifts the equilibrium of many reactions. Alignment of molecules with the field results in linear dichroism (differential absorption of linearly polarized light) and is useful to monitor large-scale conformational changes such as helix-coil transitions in nucleic acids and polypeptides. By using linearly polarized light at the magic angle, where dichroism effects are minimized, any residual signal can be attributed to chemical effects [475]. Electric-field jumps have also been combined with stopped-flow devices to perturb transient species, as illustrated in the study of cyclic adenosine monophosphate (cAMP)-receptor binding to DNA [476].
Dictionary
Published in Mario P. Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990
Magic angle. The angle 54.7° is called the magic angle because 3 cos2 Θ − 1 = 0 for this value of Θ, e.g., the dipolar coupling contains the terms 3 cos2 Θ − 1, where Θ is the angle between the internuclear vector and the applied field. Hence for an angle Θ = 54.7°, the dipolar interaction vanishes.
Exploring the influence factors and improvement strategies of drug polymorphic transformation combined kinetic and thermodynamic perspectives during the formation of nanosuspensions
Published in Drug Development and Industrial Pharmacy, 2021
Tingting Meng, Fangxia Qiao, Shijie Ma, Ting Gao, Li Li, Yanhui Hou, Jianhong Yang
The NMR can assess the physicochemical properties of the drug at the molecular level, which is based on using intrinsic reporter moieties and regardless of the sample conditions [93]. Recently, suspended-state NMR has been applied to analyze suspensions of solid and dissolved components without preprocessing [94]. Magic angle rotation (MAS) technology is combined with solid-state NMR to characterize solid powder. In suspended NMR, capsules containing suspension are placed under MAS conditions. Cross polarization (CP) technology can selectively observe solid components because it inhibits molecular mobility and induces effective CP [60]. Hasegawa et al. [60] used the 13C CP/MAS NMR spectra to analyze the molecular state of PXC. The characteristic peaks of crystal PXC were broadened, and the relative intensities of Ca, Cb, and Ck peaks compared to other peaks were significantly reduced after media milling, which may indicate that amorphous PXC appears in the nanosuspension. The suitable pulse delay times (PD) (T1 amorphous < PD<T1 crystal) showed a core–shell structure with the coexistence of crystalline and amorphous PXC enclosed by poloxamer chains, which shows partial amorphization during wet milling, as shown in Figure 6.
T2 relaxation times of knee cartilage in 109 patients with knee pain and its association with disease characteristics
Published in Acta Orthopaedica, 2021
Joost Verschueren, Stephan J Van Langeveld, Jason L Dragoo, Sita M A Bierma-Zeinstra, Max Reijman, Garry E Gold, Edwin H G Oei
Our study has several limitations. By using a clinical orthopedic population, we included patients with a wide range in age, BMI, diagnoses, and clinical symptoms. The combination of this heterogeneity and limited sample size could explain the absence of clear associations between T2 values and disease characteristics and clinical symptoms in our study. A second limitation is that we had a valid KOOS questionnaire available for only half of the patients. It was common practice at the Orthopedic Outpatient Department to ask patients to fill in the questionnaire. Unfortunately, this was not strictly controlled. We are aware that previous studies have shown T2 differences between superficial and deep cartilage layers (Mosher et al. 2004b, Bengtsson Moström et al. 2015). However, as our T2 mapping sequence is a 3D sequence with coverage of the whole knee, we considered the spatial resolution not good enough to perform these subregional analyses. Finally, we realize the magic angle effect could influence T2 values. However, as all patients were positioned in a standardized fashion, the effect would be similar for all patients. Together with the type of analyses we performed, we do not think the magic angle effect substantially influenced our results.
Microfluidic synthesis of monodisperse porous polystyrene microspheres for sorption of bovine serum albumin
Published in Journal of Microencapsulation, 2020
Natalia Shevchenko, Galina Pankova, Olga Iakobson, Rufat Abiev, Stanislav Svetlov, Nikita Ilin
The structure of the particles obtained was investigated by solid-state 1H NMR spectroscopy. The NMR spectra were recorded on an Avance 400 NMR spectrometer operating at resonance frequency of 400 MHz (1H NMR). Polymer samples were packed into zirconium rotors with a diameter of 4 mm, the spectra were registered at a temperature of 20 °C and rotation frequency of 8 or 10 kHz. The magic angle was adjusted according to KBr, the chemical shifts were evaluated with respect to adamantane (external standard). The decomposition of complex spectral lines into components was carried out using the DMFIT programme (Massiot et al.2002) on the basis of mathematical modelling, in which the ratio of the Gaussian and Lawrence functions xG/(1 − x)L for high-resolution lines was taken to be 0.5, for wide lines −0.8.