Transition radiation from graphene plasmons by a bunch beam in the terahertz regime.

The terahertz band is an increasingly important spectrum in a wide range of applications from bioimaging and medical diagnostics to security and wireless communications. We propose a tunable terahertz coherent radiation source based on graphene plasmon-induced transition radiation. The transition radiation in terahertz regime arises from the graphene plasmons, which are excited by a normally incident bunched electron beam. We analyze the field-intensities and spectral-angular distributions of the transition radiation with respect to Fermi energy, substrate dielectric permittivity, and electron bunch energy for both the coherent and incoherent radiation. The effect of electron bunching on the radiation pattern is discussed. The mechanism of plasmon frequency-selective transition radiation is discovered.

S100B protein and its clinical effect on craniocerebral injury.

OBJECTIVE: To explore the role of S100B protein in the early diagnosis, treatment, and prognosis judgement of craniocerebral injury. METHODS: In this study, we reviewed the domestic and foreign research reports about the relationship between S100B protein and craniocerebral injury. RESULTS: The concentration of S100B protein had a different increase based on the degree of injury in early stage after craniocerebral injury, and the increasing degree of S100B protein showed a positive correlation with the grading of pathogenetic condition and prognosis of craniocerebral injury. CONCLUSIONS: S100B protein may be taken as a specific index of early diagnosis, grading of pathogenetic condition, and prognosis judgement after craniocerebral injury. To grasp and regulate the mechanism of neurotoxicity and to elucidate the therapeutic effect of S100B protein will be a research direction in clinical treatment of craniocerebral injury.

Effect of recombinant human erythropoietin on serum S100B protein and interleukin-6 levels after traumatic brain injury in the rat.

Erythropoietin (EPO) has a neuroprotective effect in the animal model of ischemia/hypoxia, but the mechanisms underlying the EPO effect in traumatic brain injury (TBI) are not well understood. This study examined the potential neuroprotective mechanisms of recombinant human EPO (rhEPO) in rats after TBI. Sixty healthy adult male Sprague-Dawley rats were randomly divided into 5 groups: 1000 U/kg rhEPO-treated, 3000 U/kg rhEPO-treated, 5000 U/kg rhEPO-treated, citicoline, and normal saline (control) groups. The TBI model was based on the modified Feeney's free falling model. Serum samples were collected at 6 hours, 24 hours, 3 days, 5 days, and 7 days after trauma. The serum S100B protein and interleukin-6 (IL-6) levels were measured after treatment in each group with double antibody sandwich enzyme-linked immunosorbent assay. Both serum S100B protein and IL-6 levels were significantly lower in 3000 U/kg rhEPO-treated and 5000 U/kg rhEPO-treated groups (p < 0.001). The decrease in serum S100B protein level was correlated with the dosage of rhEPO. Medium doses of rhEPO achieved the optimum decreases in the serum IL-6 level. Therefore, inhibition of the composition and secretion of S100B protein and IL-6 levels by EPO might be one of the mechanisms involved in decreasing inflammatory reaction in the brain, and may be responsible for the neuroprotective effect after TBI.