It is well known that, in humans, contrast sensitivity training at high spatial frequency (SF) not only leads to contrast sensitivity improvement, but also results in an improvement in visual acuity as assessed with gratings (direct effect) or letters (transfer effect). However, the underlying neural mechanisms of this high spatial frequency training improvement remain to be elucidated. In the present study, we examined four properties of neurons in primary visual cortex (area 17) of adult cats that exhibited significantly improved acuity after contrast sensitivity training with a high spatial frequency grating and those of untrained control cats. We found no difference in neuronal contrast sensitivity or tuning width (Width) between the trained and untrained cats. However, the trained cats showed a displacement of the cells’ optimal spatial frequency (OSF) to higher spatial frequencies as well as a larger neuronal signal-to-noise ratio (SNR). Furthermore, both the neuronal differences in OSF and SNR were significantly correlated with the improvement of acuity measured behaviorally. These results suggest that striate neurons might mediate the perceptual learning-induced improvement for high spatial frequency stimuli by an alteration in their spatial frequency representation and by an increased SNR.

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Cryopreservation of red blood cells (RBCs) plays a vital role in preserving rare blood and serologic testing, which is essential for clinical transfusion medicine. The main difficulties of the current cryopreservation technique are the high glycerol concentration and the tedious deglycerolization procedure after thawing. In this study, we explored a microencapsulation method for cryopreservation. RBC− hydrogel microcapsules with a diameter of approximately 2.184 ± 0.061 mm were generated by an electrostatic spraying device. Then, 0.7 M trehalose was used as a cryoprotective agent (CPA), and microcapsules were adhered to a stainless steel grid for liquid nitrogen freezing. The results show that compared with the RBCs frozen by cryovials, the recovery of RBCs after microencapsulation is significantly improved, up to a maximum of more than 85%. Additionally, the washing process can be completed using only 0.9% NaCl. After washing, the RBCs maintained their morphology and adenosine 5′-triphosphate (ATP) levels and met clinical transfusion standards. The microencapsulation method provides a promising, referenceable, and more practical strategy for future clinical transfusion medicine.

Coronary artery bypass grafting (CABG) is still the most effective method for the treatment of coronary heart disease at present. However, the restenosis of vein grafts following surgery is an important complication of CABG. In this study, Bletilla striata polysaccharide (BSP), which has anti-inflammatory and antiproliferative properties, was used to prevent or delay the proliferation of venous bridge endothelial cells in a rat model. We transplanted the autogenous jugular vein to the rat carotid artery, and wrapped it with BSP. We carried out experiments in 4 groups (with 24 rats in each group): a high-BSP dose group (the HBG group, 10 mg), a low-BSP dose group (the LBG group, 3 mg), a pluronic gel group (the gel group), and a control group. Vein grafts were then harvested after 3, 14, and 28 days. Following transplantation, we used color Doppler ultrasound to assess the patency of the transplanted vein. The grafted veins were stained with hematoxylin and eosin (H&E) and Masson to measure the thickness of the intima and media of the blood vessels. Proliferating cell nuclear antigen (PCNA) and vascular cell adhesion molecule-l (VCAM-1) were assessed in vein grafts by immunohistochemistry and western blotting. We detected a significant reduction in the proliferation of endothelial cells in the BSP group compared with the control group ( P < 0.05). H&E and Masson’s trichrome staining showed that the extent of intimal hyperplasia in transplanted veins from the high BSP group (HBS) (67.42 ± 0.54 µm) and low BSP group (LBS) (120.83 ± 1.87 µm) groups was significantly lower than that in the control group (257.03 ± 2.74 µm, P < 0.05), and that the extent of intimal hyperplasia in the HBS group was lower than that in the LBS group ( P < 0.05). We found that the effect of BSP was dose-dependent, as high-dose BSP had a more significant inhibitory effect on cell proliferation than low-dose BSP ( P < 0.05). The results of immunohistochemistry and western blotting showed that PCNA and VCAM-1 were significantly downregulated in the BSP treatment group on days 14 and 28 ( P < 0.05). BSP inhibits the proliferation of vascular endothelial cells and reduces the expression of VCAM-1, thereby inhibiting the restenosis of graft veins.

Hunting monitoring is very important for high-speed trains to achieve safe operation. But all the monitoring systems are designed to detect hunting only after hunting has developed sufficiently. Under these circumstances, some damage may be caused to the railway track and train wheels. The work reported in this paper aims to solve the detection problem of small amplitude hunting before the lateral instability of high-speed trains occurs. But the information from a single sensor can only reflect the local operation state of a train. So, to improve the accuracy and robustness of the monitoring system, a multi-sensor fusion framework for detecting small amplitude hunting of high-speed trains based on an improved Dempster–Shafer (DS) theory is proposed. The framework consists of a series of steps. Firstly, the method of combining empirical mode decomposition and sample entropy is used to extract features of each operation condition. Secondly, the posterior probability support vector machine is used to get the basic probability assignment. Finally, the DS theory improved by the authors is proposed to get a more accurate detection result. This framework developed by the authors is used on high-speed trains with success and experimental findings are provided. This multi-sensor fusion framework can also be used in other condition monitoring systems on high-speed trains, such as the gearbox monitoring system, from which nonstationary signals are acquired too.