丹酚酸B和人参皂苷Rg1合用对卒中后出血性转化的抑制作用

目的:对脑卒中患者进行血管再通治疗不仅受时间窗的限制,还伴随着出血性转化的风险。本研究在小鼠大脑中动脉阻塞(MCAO)模型上观察了丹酚酸B和人参皂苷Rg1合用(Salb/Rg1)对脑缺血时间窗和出血性转化的影响。方法:通过脑梗死体积、神经行为障碍和组织形态学检查评估SalB/Rg1的保护作用和时间窗。对MCAO小鼠进行葡萄糖刺激和再灌注考察SalB/Rg1对出血性转化的抑制。SalB/Rg1对出血性转化的抑制作用是通过免疫荧光染色和原位明胶酶谱技术来确定的。结果:通过组织病理学染色根据细胞结构进一步确定SalB/Rg1以剂量依赖的方式显著减少了梗塞体积并改善了神经行为,且SalB/Rg1对卒中的保护时间窗长达9h。其次,SalB/Rg1下调了出血评分、梗死体积并改善异常神经行为。最后,发现SalB/Rg1对出血性转化的抑制与它对神经血管单元完整性的保护相伴随。在梗死的边缘区域,SalB/Rg1减少了星形胶质细胞的激活,保持了内皮细胞之间连接蛋白(Claudin-5)的丰度,大大降低了基质金属肽酶9(MMP-9)的活性。结论:SalB/Rg1是一种很有前景的抗卒中,尤其是抗出血性转化的新策略。

Traditional Chinese medicine for vascular protection in ischemic stroke

Although new drugs and intervention strategies have emerged from recent studies of neuroprotection, compared with haemodynamic and hemorheologic factors, knowledge of vascular factors of ischemic stroke is rather limited. In practical terms, any strategy shown to reduce the incidence of fatal and nonfatal vascular events can be termed ＂vascular protection＂, including anti-thrombotic and anti-hypertensive therapies, as well as agents that directly benefit vascular endothelium. Vascular events include myocardial infarction, stroke, and claudication. Factors involved in these events include statins, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers. In traditional Chinese medicine, the principles of ＂activating blood circulation to remove stasis＂, ＂tonifying the kidney and replenishing the essence＂, ＂dispelling pathogenic wind and removing obstruction from the meridians＂, and ＂warming Yang and promoting water metabolism＂ are possibly related to vascular protection. However, more evidence is needed to correlate these positive effects with vascular protection.

A pure dielectric metamaterial absorber with broadband and thin thickness based on a cross-hole array structure

A pure dielectric metamaterial absorber with broadband and thin thickness is proposed,whose structure is designed as a periodic cross-hole array.The pure dielectric metamaterial absorber with high permittivity is prepared by ceramic reinforced polymer composites.Compared with those with low permittivity,the absorber with high permittivity is more sensitive to structural parameters,which means that it is easier to optimize the equivalent electromagnetic parameters and achieve wide impedance matching by altering the size or shape of the unit cell.The optimized metamaterial absorber exhibits reflection loss below-10 dB in 7.93 GHz–35.76 GHz with a thickness of 3.5 mm,which shows favorable absorption properties under the oblique incidence of TE polarization(±45°).Whether it is a measured or simulated value,the strongest absorbing peak reaches below-45 dB,which exceeds that of most metamaterial absorbers.The distributions of power loss density and electric and magnetic fields are investigated to study the origin of their strong absorbing properties.Multiple resonance mechanisms are proposed to explain the phenomenon,including polarization relaxation of the dielectric and edge effects of the cross-hole array.This work overcomes the shortcomings of the narrow absorbing bandwidth of dielectrics.It demonstrates that the pure dielectric metamaterial absorber with high permittivity has great potential in the field of microwave absorption.

The Cytocompatibility of Genipin-Crosslinked Silk Fibroin Films

There is an increasing demand for crosslinking methods of silk fibroin (SF) scaffolds in biomedical applications that could maintain the biocompatibility, bioactivity as well as improve the water resistance and mechanical properties of SF materials. In this study, SF was crosslinked effectively with genipin which is a naturally occurring iridoid glucoside and the crosslinking mechanism was investigated through FTIR and amino acid analysis. The results showed that genipin could react with the -NH2 groups on the side chains of SF macromolecules and to form inter- and intra-molecular covalent bonds, and improved the stability of SF materials significantly. In vitro, the performances of genipin-crosslinked SF films were assessed by seeding L929 cells and compared with ethanol-processed SF films, glutaraldehyde and polyethylene glycol diglycidyl ether crosslinked ones. The genipin-crosslinked SF films showed a similar affinity to cells as ethanol-processed ones, and a higher bioactivity in promoting cell growth and proliferation, inhibition of cell apoptosis, and maintenance of normal cell cycle compared with glutaraldehyde and polyethylene glycol diglycidyl ether crosslinked SF films. These features, combined with the decrease of brittleness of SF films crosslinked with chemical methods, substantiated genipin as an effective and biocompatible agent for the manufacturing of bioactive SF materials which used as tissue engineering scaffolds and drug delivery carriers.

Scutellarin alleviates liver injury in type 2 diabetic mellitus by suppressing hepatocyte apoptosis in vitro and in vivo

Objective: Scutellarin is a primary active composition come from Erigeron breviscapus. It is well known that scutellarin has anti-infammatory and antioxidant physiological functions. In this study, we detected the effects of scutellarin on hepatocyte cell apoptosis in type 2 diabetes mellitus(T2DM) rats.Methods: Sprague Dawley(SD)(6–8 weeks, 160–180 g) rats were randomly divided into six groups: control, model, scutellarin low-dose, medium-dose, high-dose treatment, and rosiglitazone positive groups;with 10 SD rats in each group(n = 10). The changes of biochemical factors in serum were detected by automatic biochemical instrument, the pathological changes of liver tissue were detected by hematoxylin and eosin(HE) staining, the apoptosis of liver tissue and cells was detected by tissue staining and fow analyzer, and the expression of apoptosis-related factors were determined by q PCR, Western blot and immunohistochemistry in liver tissues or cells.Results: The results showed that scutellarin decreased the levels of fasting blood glucose, total cholesterol, triglyceride, and low-density lipoprotein and increased the levels of high-density lipoprotein.Meanwhile, scutellarin decreased the levels of alanine transaminase(ALT) and aspartate transaminase(AST) and improved liver function. In addition, scutellarin suppressed the secretion of interleukin-1(IL-1), interleukin-6(IL-6) and tumor necrosis factor-a(TNF-a) and reduced hepatocyte apoptosis.Furthermore, scutellarin inhibited the expression of cleaved Caspase-3, Bax, and cytochrome C(Cyt-C)and promoted the expression of Bcl-2.Conclusion: Scutellarin can inhibit the apoptotic pathway, thereby relieving T2DM.

Effect of Ni content in Cu_(1-x)Ni_(x) coating on microstructure evolution and mechanical properties of W/Mo joint via low-temperature diffusion bonding

The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coating interlayer on the interfacial microstructure evolution and mechanical properties of the W/Mo joints were studied.The maximum average shear strength of the W/Mo joint was 316.5 MPa when the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was 25%.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was below 50%,the atomic diffusion at the W/Mo joint interface was adequate without the formation of intermetallic compounds,as demonstrated by the High Resolution Transmission Electron Microscope analyses of the joints.The presence of Ni in Cu_(1-x)Ni_(x) promoted diffusion bonding at the interface,which contributed to the high mechanical properties of the W/Mo joint.With an increase in the Ni content of the Cu_(1-x)Ni_(x) coating interlayer,the Mo Ni intermetallic compound(IMC)nucleated and grew at the Cu1-xNix coating/Mo1 interface.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was above 50%,the generation of a brittle Mo Ni IMC weakened the shear strength of the W/Mo joint dramatically.