Establishment of a rhesus monkey model of middle cerebral artery ischemia and reperfusion using a microcatheter embolization method

Nonhuman primates are closest to humans in terms of lineage, and middle cerebral artery ischemia/reperfusion responses of nonhuman primates are most similar to ischemic stroke in humans. Therefore, nonhuman primates could be utilized to simulate the process of ischemic stroke in the human. Few studies, however, have reported the use of endovascular technology to establish a rhesus monkey stroke model. In the present study, seven adult, male, rhesus monkeys were selected and, following anesthesia, a microcatheter was inserted into one side of the middle cerebral artery via the femoral artery to block blood flow, thereby resulting in middle cerebral artery occlusion. After 2 hours, the microcatheter was withdrawn to restore the middle cerebral artery blood flow and to establish ischemia/reperfusion. Results from angiography and magnetic resonance angiography confirmed occlusion and reopening of the middle cerebral artery. Magnetic resonance imaging revealed the existence of ischemic brain lesions, and neurological examination showed sustained functional deficits following surgery. The rhesus monkey middle cerebral artery ischemia/reperfusion models established by microcatheter embolization had the advantage of non-craniotomy invasion and reproducibility. The scope and degree of ischemic damage using this model was controllable. Therefore, this nonhuman primate model is an ideal model for cerebral ischemia and reperfusion.

Defects and doping engineering towards high performance lead-free or lead-less perovskite solar cells

Up to now, perovskite solar cells(PSCs) have reached a certified 25.5% efficiency. As a promising photo-electric material, the metal halide perovskite possesses many outstanding properties such as tunable bandgap, long diffusion length, high absorption coefficient and carrier mobility. In spite of these remarkable properties, defects are inevitable during the solution processing. Therefore, many efforts have been made to reduce defects in perovskite films and thus improve the performance of devices. Among them,substitution or doping engineering is one of the most studied methods. Meanwhile, due to the poor stability of the organic-inorganic hybrid perovskite and the toxicity of Pb-based perovskite materials, all inorganic perovskite and lead-less or lead-free perovskite have emerged as promising materials. Here,we focus on the defect engineering especially substitutions on different sites in an ABX_(3) structure. The particular attention is devoted towards lead-less or lead-free perovskites, and we discuss several common elements or groups used to partially replace Pb^(2+). It is noted that proper elemental doping at different sites is an important guarantee for obtaining high-performance lead-less or lead-free PSCs.

Voltammetric Method Using Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode for the Determination of Terbutaline Sulfate in Pork Sample

Electrochemical properties of terbutaline sulfate (TBS) at the glassy carbon electrode modified with multi-walled carbon nanotubes (MWNTs) were explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The response was evaluated with respect to pH, scan rate and other variables. Some electrochemical parameters, such as the charge number and proton number, were calculated. The results indicated that TBS underwent irreversible oxidation at the modified electrode, which was an adsorption-controlled process with two protons and two electrons. The reductive peak current of TBS significantly increased and the peak potential shifted negatively at the modified electrode, thus resulting in an electrode for TBS. The current was proportional to the concentration of TBS over 1.12 and 141 μM with a detection limit of 0.34 μM (at S/N = 3). The modified electrode showed good sensitivity, selectivity and stability for the determination of TBS in pork sample.