[en] Objective: To analyse the changes in bilateral optic radiation and visual cortex in patients with primary glaucoma detected by magnetization transfer imaging (MTI), and try to explore the influence of the disease on posterior visual pathway. Methods: MTI was performed in 20 patients with primary glaucoma with normal signal on conventional magnetic resonance imaging (MRI). The same scanning was performed in 31 matched healthy controls. MTI was obtained using spoiled gradient recalled acquisition sequence (SPGR). Magnetization transfer ratio (MTR) of bilateral optic radiation and visual cortex was measured after post-processing. The MTR value differences of the same area between two groups were compared by independent-sample t test or Satterthwaite t test if variances were not equality. Result: The MTR value in the left and right optic radiation were (32.8 ± 2.2)% and (32.7 ± 2.0)% in the glaucoma group, (34.6 ± 1.4 )% and (34.8 ± 1.3)% in the control group. There was a statistically significant difference between the two groups (left t=3.284, right t=4.040; P<0.01). The MTR value of the left and right visual cortex were (30.1± 2.0)% and (30.8 ± 1.8)% in the glaucoma group, and (32.3 ± 1.2 )% and (32.4 ± 1.2)% in the control group. Statistically significant difference was found between the two groups (left t=4.319, right t=3.445; P<0.01). Conclusions: Potential neuropathology changes occurring in the posterior visual pathway of patients with glaucoma indicate that the whole visual pathway may be involved by glaucoma.The micro physiological changes can be detected by MTI which can not be found by conventional MRI. It is a useful method of studying trans-synaptic damage of visual pathway n vivo glaucoma which provides more information for guiding the clinic diagnosis, cure and prognosis of glaucoma. (authors)

[en] Objective: To discuss the application of CT multiplanar reformation (CTMPR) technique in making preoperative evaluation of stent implantation therapy for malignant colonic obstruction. Methods: The clinical data of a total of 50 patients with malignant colonic obstruction who received stent implantation therapy were retrospectively analyzed. Combined with the characteristics of CTMPR technique, the value of CTMPR technique in stent implantation was assessed. Results: Depending on the related information provided by CTMPR imaging, higher success rate of colonic stent implantation was obtained. The short-term curative effect was satisfactory, and the colonic obstruction was relieved within 24 hours after stent implantation therapy in most patients. Conclusion: CTMPR imaging can provide comprehensive and useful data for colon stent implantation, which can ensure the successful management of colonic stent implantation, thereby, the success rate of stent implantation can be well improved. (authors)

[en] Highlights: • The near-field radiative thermal switch made of the n-type doped silicon and graphene-covered silicon dioxide plates is comprehensively investigated. • The modulation is due to the surface mode of the graphene-covered silicon dioxide, which is significantly affected by the graphene chemical potential value via applying the external voltage bias. • The D-Si doping concentration and the breakdown voltage of dielectric materials also can significantly affect the performance of the near-field radiative thermal switch. • The thermal switching factor of the near-field radiative thermal switch can be improved to 93.5% across a 10 nm vacuum gap by altering the graphene chemical potential value from 0 to 1 eV. The key to the micro/nanoscale thermal management of precision instruments is flexibly controlling the heat flux in the near-field following the actual demand. In this paper, a near-field radiative thermal switch (NFRTS) made of the n-type doped silicon (D-Si) and graphene-covered silicon dioxide (SiO₂) plates is proposed to achieve the active near-field radiative heat transfer modulation. The radiative heat flux, thermal switching factor, and thermal modulation factor are calculated for different graphene chemical potential values from 0 to 1 eV and D-Si doping concentrations at different vacuum gaps. This is achieved by considering the breakdown voltage of the SiO₂, and with the fluctuational electrodynamics and fluctuation-dissipation theorem. The SiO₂ is also replaced by the silicon carbide (SiC) in the thermal switch to clarify further the effect of the breakdown voltage on the performance of the NFRTS. In combining the graphene chemical potential value and D-Si doping concentration, it is obtained that the optimal thermal switching factor is 93.5% for a doping concentration of 10¹⁸ cm⁻³ at a 10 nm vacuum gap for SiO₂ system when the heat source and heat sink temperatures are 400 K and 300 K, respectively. This is mainly due to the combination of the major angular frequency band of the transmission coefficients for bulk D-Si determined by the doping concentration and the surface mode of the graphene-covered SiO₂ modulated by altering the graphene chemical potential value via applying the external voltage bias. Results also reveal that the performance of the NFRTS with SiC substrate is significantly affected and weakened by the limited breakdown voltage of SiC, and almost always worse than that of the NFRTS with SiO₂ substrate. This work paves a way for designing the active near-field thermal management devices for simple structures.