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Terahertz near-field data of different samples.

We report on a scattering-type scanning near-field optical microscope (s-SNOM) based on a terahertz quantum cascade laser (QCL) and a fast terahertz quantum-well photodetector (QWP). The natural polarization of terahertz QWP and terahertz QCL can improve the coupling efficiency. A resolution of about 60 nm is obtained.

The fast detection of terahertz radiation is recognized as a key technology of terahertz imaging systems. We realize a terahertz imaging system employing a terahertz quantum-well photodetector (QWP) and a terahertz quantum cascade laser (QCL). The detector can rapidly detect the 4.3THz light generated from a pulsed electrically-pump terahertz QCL, which is used as the terahertz source of the imaging system. The object is placed on a rotary scanning platform to realize fast scanning. A practical detection method of the terahertz pulse signal is employed to extract the amplitude information from the terahertz signal and improve the signal-to-noise ratio (SNR) of the system. The electrical and optical performances of the fast terahertz QWP are characterized, and the results show that the terahertz QWP can completely meet the fast detection requirement of the terahertz imaging system. The terahertz images of some invisible objects are obtained with a high contrast within 5 s. The imaging system owns a resolution of 0.3 mm and a circular imaging region with a diameter of 100 mm. An image processing algorithm is applied in this system to solve the noise problem and improve the quality of the images. The imaging results indicate that terahertz QWP has a good application prospect in nondestructive inspection applications and the research of the fast physical or chemistry process.

For the terahertz imaging systems, the fast detection of terahertz light is deemed as a key technology. We present a fast terahertz reflective confocal scanning imaging system employing a fast terahertz quantum-well photodetector (QWP) and a fast rotating translational platform. The excellent performance of the terahertz QWP indicates that the device can rapidly detect the 4.3 THz radiation generated from a pulsed electrically pumped terahertz quantum cascade laser, which is used as the terahertz source of the imaging system. Two 200 μm pinholes are placed in the two focuses to filter out the scattered light and improve the resolution of the imaging system, we achieve a lateral resolution better than 110 μm and an axial resolution of about 320 μm. The terahertz two-dimension images of some objects are obtained within 5 s with a high contrast. The three-dimensional sections of the object demonstrate the great axial selectivity of the terahertz imaging system.

Changping Dun,1 Junqian Liu,1 Fucheng Qiu,1 Xueda Wu,2 Yakun Wang,3 Yongyan Zhao,4 Ping Gu1 1Department of Neurology, the First Hospital of Hebei Medical University, 2Department of Cardiac Surgery, the Second Hospital of Hebei Medical University, 3Department of Endocrinology, the Fourth Hospital of Hebei Medical University, Shijiazhuang, 4Department of Nursing, Maternal and Child Health Hospital of Tangshan City, Tangshan, People’s Republic of China Objective: Astragalus polysaccharides (APS) are active constituents of Astragalus membranaceus. In this study, we aimed to investigate the effects of APS on memory impairment in a diabetic rat model and their mechanisms. Methods: A diabetic model was established in 50 male Wistar rats with streptozotocin intraperitoneal injection. A blood glucose level higher than 16.7 mmol/L obtained 72 hours after the injection was regarded as a successful diabetic model. The modeled rats were divided into model group, high, medium, and low doses of APS, and piracetam groups (positive control). A group of ten rats without streptozotocin-induced diabetes were used as a normal control. After respective consecutive 8-week treatments, the levels of blood fasting plasma glucose, insulin, hemoglobin A1c, memory performance, hippocampal malondialdehyde, and superoxide dismutase were determined. Results: After the 8-week APS treatment, serum fasting plasma glucose, hemoglobin A1c, and insulin levels were decreased compared with those of the model group (P

Objective: Human umbilical cord mesenchymal stem cells (hUC-MSCs) hold substantial promise for the treatment of ischemic neurological disease, but few clinical data are currently available about its therapeutic effects in hypoxic ischemic encephalopathy (HIE). This study is to evaluate the effects of hUC-MSCs transplantation on patients with HIE. Methods A total 22 patients with HIEwere randomly divided into hUC-MSCs transplantation group (n = 12) and control group (n = 10). After isolation, hUC-MSCs were cultured for 3 to 5 passages in vitro and then intravenously administered to HIE patients in the transplantation group, while the control group received routine treatment only. The outcomes of HIE patients were evaluated at designated time points by clinical assessment scales, including NIHSS, Barthel Index, MMSE, HAMA24, HAMD14 and UPDRS. Results: hUC-MSCs were identified by morphological analysis and flow cytometry assays before clinic transplantation. No significant differences of demographic characteristics were observed between the two groups of subjects. Compared to the control group, hUC-MSCs transplantation markedly improved the outcomes of HIE patients leading to better recovery of neurological function, cognition ability, emotional reaction and extrapyramidal function. No significant adverse effects were found in subjects with hUC-MSCs transplantation during a 180-day follow-up period. Conclusion: These data suggest that hUC-MSCs therapy markedly improves the outcomes of patients with HIE, which is potential for the routine treatment of ischemic neurological disease.