MagTetris: A simulator for fast magnetic field and force calculation for permanent magnet array designs.

In this paper, a simulator named "MagTetris" is proposed for fast magnetic field (B-field) and force calculation for permanent magnet arrays (PMAs) designs consisting of cuboid and arc-shaped magnets (approximated by cuboids) with arbitrary configurations. The proposed simulator can compute the B-field of a PMA on arbitrary observation planes and the magnetic force acting on any magnet/group of magnets. An accelerated calculation method for B-fields of PMAs is developed based on the current model of permanent magnet, which is further extended to magnetic force calculation. The proposed method and the associated codes were validated with numerical simulation and experimental results. The calculation speed of "MagTetris" is at least 500 times higher than that using finite-element method (FEM)-based software with uncompromised accuracy. Compared with a freeware in Python, Magpylib, "MagTetris" has a calculation acceleration of greater than 50% using the same language. "MagTetris" has a simple data structure, which can be easily migrated to other programming languages maintaining similar performances. This proposed simulator can accelerate a PMA design and/or allow designs with high flexibility considering the B-field and force simultaneously. It can facilitate and accelerate innovations of magnet designs to advance dedicated portable MRI in terms of compactness, weight, and performance.

High-performance permanent magnet array design by a fast genetic algorithm (GA)-based optimization for low-field portable MRI.

Lightweight and compact permanent magnet arrays (PMAs) are suitable for portable dedicated magnetic resonance imaging (MRI). It is worth exploring different PMA design possibilities and optimization methods with an adequate balance between weight, size, and performance, in addition to Halbach arrays and C-shaped/H-shaped magnets which are widely used. In this paper, the design and optimization of a sparse high-performance inward-outward ring-pair PMA consisting of magnet cuboids is presented for portable imaging of the brain. The design is lightweight (151kg) and compact (inner bore diameter: 270mm, outer diameter: 616mm, length: 480mm, 5-Gauss range: 1840×1840×2340mm3). The optimization framework is based on the genetic algorithm with a consideration of both field properties and simulated image quality. The resulting PMA design has an average field strength of 101.5 mT and a field pattern with a built-in linear readout gradient. Subtracting the best fit to the linear gradient target resulted in a residual deviation from the target field of 0.76mT and an average linear regression coefficient of 0.85 to the linear gradient. The required radiofrequency bandwidth is 6.9% within a field of view (FoV) with a diameter of 200mm and a length of 125mm. It has a magnetic field generation efficiency of 0.67mT/kg, which is high among the sparse PMAs that were designed for an FoV with a diameter of 200mm. The field can be used to supply gradients in one direction working with gradient coils in the other two directions, or can be rotated to encode signals for imaging with axial slice selection. The encoding capability of the designed PMA was examined through the simulated reconstructed images. The force experienced by each magnet in the design was calculated, and the feasibility of a physical implementation was confirmed. The design can offer an increased field strength, and thus, an increased signal-to-noise ratio. It has a longitudinal field direction that allows the application of technologies developed for solenoidal magnets. This proposed design can be a promising alternative to supplying the main and gradient fields in combination for dedicated portable MRI. Lastly, the design is resulted from a fast genetic algorithm-based optimization in which fast magnetic field calculation was applied and high design flexibility was feasible. Within optimization iterations, image quality metrics were used for the encoding field of a magnet configuration to guide the design of the magnet array.

Investigation on mental health of general practice students in a medical school in Jiangsu Province / 中华全科医师杂志

A survey on mental health status was conducted during October 2021 to January 2022 among grade 2017—2021 medical students majored in general practice who received 3+2-year education integrated undergraduate study and residency training for assistant physicians in a medical school in Jiangsu province. The SCL-90 and the self-made scale were used to investigate the mental health status and the results were compared with the national norm, the norm of national physicians, and the norm of medical students in Jiangsu province. A total of 125 valid questionnaires were recovered, and the positive detection rate of SCL-90 scale was 17.6%. Compared with the national norm in 2015, the scores of forcing ( t=-2.47), the interpersonal sensitivity ( t=-2.00), the hostile ( t=-2.65), the paranoid( t=-3.14) and the psychiatric factor( t=-2.45) of the study group were significantly lower than those of the norm ( P<0.05). Compared with the norm of national physicians and the norm of medical students in Jiangsu province, the scores of all the items except the fear factor were lower than those of the norms ( P<0.05). In the study group there were no significant differences in the total score and all factors among students with different genders, different training stages, and different background. The total score of SCL-90 scale was negatively associated with the study performance and clinical skill mastery ( r=-0.18) and the sense of achievement ( r=-0.23, P<0.05). The study shows that the mental health status of this group of students is generally better than that of the several norms.

Considerations on the chemistry, manufacture and control requirements for conditional marketing authorization drugs in China / 中国药科大学学报

@#Drug Administration Law revised in 2019 proposed for the first time conditional marketing authorization at the legal level, marking the formal implementation of the conditional marketing authorization in China. This paper compares the regulations and technical requirements of conditional marketing authorization drugs in China with those in Europe and the United States, in an attempt to learn from the experience of chemistry, manufacture and control review of these drugs in Europe and the United States, and to discuss the pharmaceutical technical requirements of conditional marketing authorization drugs in China.

Quercetin inhibits okadaic acid-induced tau protein hyperphosphorylation through the Ca2+­calpain­p25­CDK5 pathway in HT22 cells.

Alzheimer's disease (AD) is a common neurodegenerative disorder characterized by aberrant tau protein hyperphosphorylation, which eventually leads to the formation of neurofibrillary tangles. Hyperphosphorylated tau protein is considered as a vital factor in the development of AD and is highly associated with cognitive impairment. Therefore, it is recognized to be a potential therapeutic target. Quercetin (QUE) is a naturally occurring flavonoid compound. In the present study, the inhibitory effect of QUE on okadaic acid (OA)-induced tau protein hyperphosphorylation in HT22 cells was explored. Western blotting results indicated that QUE significantly attenuated OA­induced tau protein hyperphosphorylation at the Ser396, Ser199, Thr231 and Thr205 sites. Further experiments demonstrated that QUE inhibited the activity of cyclin­dependent kinase 5 (CDK5), a key enzyme in the regulation of tau protein, and blocked the Ca2+­calpain­p25­CDK5 signaling pathway. These observations indicate the ability of QUE to decrease tau protein hyperphosphorylation and thereby attenuate the associated neuropathology. In conclusion, these results support the potential of QUE as a therapeutic agent for AD and other neurodegenerative tauopathies.

Neutralizing anti-CD44 antibodies suppresses the growth of B16 cells and enhances AKT-mediated glycolytic metabolism in melanoma / 医学研究生学报

Objective CD44, a cell surface glycoprotein, plays an important role in tumor growth and glycolysis.The aim of this study was to investigate the effects of neutralizing CD44 antibodies on the growth and glycolytic metabolism of B16 cells in melanoma in vitro.Methods B16 cells were treated with control antibodies (50 μg/mL) or different concentrations of CD44 antibodies (2, 10, and 50 μg/mL) for 24 hours, followed by examination of the activation of the AKT pathway in the B16 cells by Western blot.Then the tumor cells were also treated with control antibodies (50 μg/mL) or CD44 antibodies (50μg/mL) after pretreated with API-2 (4 μmol/L) in a parallel test.After 48 hours of treatment, the expression of lactate dehydrogenase A (LDHA) in the B16 cells and the level of lactate in the culture supernatant were detected by immunofluorescence and colorimetry, respectively.Lastly, the B16 cells were treated with control antibodies (50μg/mL), API-2 (4 μmol/L), CD44 antibodies (50μg/mL), or API-2 + CD44 antibodies for 96 hours, followed by measurement of the proliferation of the cells by MTT and their apoptosis by AO/EB and AnnexinV staining.Results In comparison with the control antibody group, the level of AKT phosphorylation (p-AKT) in the B16 cells showed a concentration-dependent increase in the 2, 10, and 50 μg/mL CD44 antibody groups (1.00±0.25 vs 2.51±0.32, 3.89±0.46, and 4.07±0.42, P<0.01), and the expression of LDHA was increased by (2.13±0.24) times, with the lactate level in the culture supernatant significantly elevated from (35.32±3.24) to (56.34±8.19) mmol/L (P<0.01) after 96 hours of treatment with 50 μg/mL CD44 antibodies.Treatment with API-2+CD44 antibodies, however, suppressed the increase in the LDHA expression and reduced the level of lactate.Compared with the control antibody group, the proliferation rate of the B16 cells was markedly decreased in the API-2, CD44 antibody, and API-2+CD44 antibody groups ([103±12.91] vs [84.87±19.35], [71.35±16.23], and [41.16±9.15]%, P<0.05), while the apoptosis rate remarkably increased ([5.23±0.96] vs [13.65±4.27], [19.21±3.53], and [43.21±7.87]%, P<0.01).Conclusion Neutralizing the function of CD44 in the B16 cells in vitro can inhibit the growth of the cells and promote AKT-mediated glycolytic metabolism, while suppressing the AKT pathway may enhance the antitumor activity of the CD44 antibody.