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The Medium Energy X-ray Telescope (ME) is one of the main payloads of the Hard X-ray Modulation Telescope (dubbed as Insight-HXMT). The background of Insight-HXMT/ME is mainly caused by the environmental charged particles and the background intensity is modulated remarkably by the geomagnetic field, as well as the geographical location. At the same geographical location, the background spectral shape is stable but the intensity varies with the level of the environmental charged particles. In this paper, we develop a model to estimate the ME background based on the ME database that is established with the two-year blank sky observations of the high Galactic latitude. In this model, the entire geographical area covered by Insight-HXMT is divided into grids of $5^{\circ}\times5^{\circ}$ in geographical coordinate system. For each grid, the background spectral shape can be obtained from the background database and the intensity can be corrected by the contemporary count rate of the blind FOV detectors. Thus the background spectrum can be obtained by accumulating the background of all the grids passed by Insight-HXMT during the effective observational time. The model test with the blank sky observations shows that the systematic error of the background estimation in $8.9-44.0$ keV is $\sim1.3\%$ for a pointing observation with an average exposure $\sim5.5$ ks. We also find that the systematic error is anti-correlated with the exposure, which indicates the systematic error is partly contributed by the statistical error of count rate measured by the blind FOV detectors., Comment: to be published in Journal of High Energy Astrophysics

Systematic scanning electron microscopic observations of the healing mechanism in the endothelium of rat carotid arteries were carried out at the site of anastomosis. The site of needle holes and stitches are the main locations for thrombocyte adhesion and aggregation in normal vascular anastomosis. The repair process in endothelial injury can be divided into three stages. A thrombocyte-adhesion and filling stage is apparent at 1 hr postoperatively; this is also the period when thrombus is most likely to occur. A fibrin-covering stage is apparent at 2 hr after operation and reaches its peak in 24 hr. The formation of fibrin provides a framework for endothelial growth. In this period, there is still the possibility of thrombus formation. At 48 hr postoperatively, endothelial growth can be seen at the site of some needle holes. At 72 hr after operation, 47 percent of needle holes have endothelial growth, and the possibility of thrombus formation at the anastomotic site declines. The data suggest that eversion of the intima in vascular anastomosis and minimization of endothelial injury by considering the size of the needle hole, the duration of ischemia time, and perfection of surgical technique, are keys to the prevention of thrombus formation at the anastomotic site.

We report a series of 164 patients who underwent phrenic neurotization to elements of the brachial plexus with root avulsion injuries. Recipient nerves included musculocutaneous nerve in 125 patients (78 direct neurotizations and 48 with intervening autograft), median nerve in 10 patients, and a variety of other nerves in 28 patients. Sixty-five patients presented a follow-up period of 2 or more years. Of this group, 55 patients (84.6%) achieved a recovery of M-3 or better. We observed no long-term deleterious effects on respiratory function.

On the basis of our experience with 200 cases undergoing free toe transfer for reconstruction of the thumb and fingers, circulatory crisis during and after operation has been analysed in this paper with our classification according to the time of occurrence. In circulatory crisis during operation or within 24 h postoperatively early exploration is indicated. Crises occurring 24, especially 48 h after operation are mainly due to vascular spasm, therefore antispasmodic therapy should be instituted whereas surgical intervention is useless and even harmful.