内向整流钾通道对少突胶质前体细胞发育的作用

目的研究内向整流钾通道Kir4.1对少突胶质细胞(OL)发育的作用。方法体外原代分离培养少突胶质前体细胞(OPC),利用PCR和Western blot技术检测OPC和成熟OL中Kir4.1和髓鞘相关蛋白MBP的基因和蛋白表达水平。用desipramine(DES)阻断Kir4.1通道后,再检测细胞增殖和分化及MBP的表达情况。结果Kir4.1在OL细胞中表达升高,阻断Kir4.1可以促进OPC增殖,但是抑制OPC向OL细胞分化。结论Kir4.1在OL细胞发育过程中发挥着重要作用。

Evaluation of yields and quality parameters of oils from Cornus wilsoniana fruit extracted by subcritical n-butane extraction and conventional methods

Cornus wilsoniana fruit oil is a very important woody oil and is the main raw material of biodiesel.In this study,the oil yield,physicochemical properties,fatty acid composition,rheological properties,thermal stability,and Fourier transform infrared(FTIR)spectra of C.wilsoniana fruit oil obtained by subcritical n-butane extraction(SBE)and conventional methods such as pressing extraction(PE)and Soxhlet extraction(SE)were determined to study the influence of different extraction methods on the quality and yield of C.wilsoniana fruit oil.The oil yield of SBE(19.47%)was higher than that of PE(9.93%)but slightly lower than that of SE(21.08%).All of the extracted oils exhibited similar physicochemical properties,and the SBE oil was richer in polyunsaturated fatty acids(PUFA)than that of the PE oil,with an approximate 1:2 ratio of total saturated fatty acids against unsaturated fatty acids.The results of rheological behavior and thermal stability showed that all extracted oils had Newtonian flow characteristics,wherein the SBE oil exhibited lower viscosity and higher thermal stability.Furthermore,scanning electron microscopy(SEM)images of the surface topography indicated that different oil extraction methods will affect the residual oil content of the C.wilsoniana fruit powder.Compared with PE,the pores on the surface of the C.wilsoniana fruit powder after oil extraction were clearly visible,indicating that the driving force of SBE for oil extraction is stronger than that of PE.Based on the above results,it is implied that SBE is the best of the three methods for extracting C.wilsoniana fruit oil and can be potentially applied to extract other edible oils.

Association of a complete breast cancer pathologic response with axillary lymph node metastasis via neoadjuvant chemotherapy:Results from the CSBrS-012 study

To the Editor:In the last decade,neoadjuvant chemotherapy(NAC)has become a well-accepted treatment option for breast cancer,although few detailed description of NAC in China has yet been reported.[1]A previous study found that among patients with clinically node-negative(cN0)breast cancer,97.7%(432/442)with breast pathologic complete response(bpCR)had ypN0(absence of metastases in the axillary lymph nodes);and 71.6%(882/1232)without bpCR achieved ypN0(P<0.001).As for human epidermal growth factor receptor 2(HER2)positive or triple-negative breast cancer(TNBC)that achieved bpCR.

杂Diels-Alder环加成反应级联RAFT聚合

Diels-Alder(DA)反应温度可逆、无需催化剂、高效快速且无有害产物,成为构建可自愈和可回收的动态共价弹性体网络的有利选择。然而传统的DA反应(比如呋喃和马来酰亚胺)存在反应时间长、反应温度高和模块化差等问题。近年来研究发现,具有高反应性的二烯可与特异性的RAFT试剂发生HDA反应(含杂原子硫的Diels-Alder环加成反应),实现HDA反应与RAFT聚合的高效级联,降低DA反应温度及反应时间的同时,又将RAFT聚合对于聚合物分子量以及分子量分布的精确可控性结合到DA反应中,在制备高分子量嵌段及接枝聚合物、表面修饰等方面有广泛的应用潜力。本文综述了近十五年来HDA-RAFT级联反应的研究与应用,探讨了目前仍存在的一些问题和解决方法,并对未来这一领域的发展进行了展望。

Aging effects on rheological properties of high viscosity modified asphalt

This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer,respectively.The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope.Besides,a study was performed to compare the aging effects on the rheological properties of HVMA,crumb rubber modified asphalt(CRMA),and neat asphalt(SK-90).The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging.The complex shear modulus of the HVMA was improved by the aging in the whole frequency range.The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging.Thus,the aging improved the high-temperature viscoelastic performance of HVMA.With a decrease in temperature from-12℃to-24℃,the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase.Both of the short-and long-term aging of HVMA were caused by an oxidation reaction,while modifier swelling also happened after long-term aging.Compared to CRMA and SK-90,aging had a limited influence on the high-and low-temperature rheological properties of HVMA.

Investigation of internal phases of linear SBS modified bitumen at the nanoscale using AFM PF-QNM

Currently,few studies explore the internal phases of styrene-butadiene-styrene(SBS)modified bitumen at the nanoscale,though the surface phases of SBS modified bitumen have been deeply understood through a lot of research.The present study uses the atomic force microscopy(AFM)peak force quantitative nanomechanical mode(PF-QNM)to investigate the nanomechanical properties of the interior of linear SBS modified bitumen and corresponding mastics at the nanoscale.Firstly,the suitable experimental methods for the interior of bitumen and mastics are explored.Then,the phase relationship between surfaces and interiors of linear SBS modified bitumen is determined by analyzing nanomechanical properties.On this basis,in comparison with the internal phases of base bitumen,the effect of modifiers on phases is deeply investigated.Finally,the internal phases of linear SBS modified bituminous mastics are further investigated.The results reveal that the interior of linear SBS modified bitumen only has two phases,which form in a manner like periphase and paraphase on the surface.In contrast to base bitumen,linear SBS modified bitumen does not create new phases and change the properties of original phases in the interior,but affects the proportion of A-phase and B-phase and presents the homogenization.Furthermore,due to the influence of preparation methods,only the bitumen area away from the fillers can be imaged by AFM PF-QNM.It can be found that the addition of mineral fillers also slightly changes the internal phase distribution of linear SBS modified bitumen,while the effect is less than that of fillers on base bitumen.

Overcoming HBV immune tolerance to eliminate HBsAg-positive hepatocytes via pre-administration of GM-CSF as a novel adjuvant for a hepatitis B vaccine in HBV transgenic mice

Granulocyte-macrophage colony-stimulating factor （GM-CSF） is known to be a potential vaccine adjuvant despite contradictory results from animal and human studies. The discrepancies may be due to the different doses and regimens of GM-CSF that were used, given that either mature or immature dendritic cells （DCs） could be induced under different conditions. To test the hypothesis that GM-CSF can be used as a novel adjuvant for a hepatitis B virus （HBV） therapeutic vaccine, we administered GM-CSF once per day for three days prior to vaccination with recombinant HBV vaccine （rHBVvac） in mice. We observed greater DC maturation in these pre-treated animals at day 3 as compared to day 1 or day 2 of daily GM-CSF administration. This strategy was further investigated for its ability to break the immune tolerance established in hepatitis B surface antigen-transgenic （HBsAg-Tg） animals. We found that the levels of induced anti-HBsAg antibodies were significantly higher in animals following three days of GM-CSF pre-treatment before rHBV vaccination after the third immunization. In addition to the increase in anti-HBsAg antibody levels, cell-mediated anti-HBsAg responses, including delayed-type hypersensitivity, T-cell proliferation, interferon-y production, and cytotoxic T lymphocytes, were dramatically enhanced in the three-day GM-CSF pre-treated group. After adoptive transfers of CD8＋ T cells from immunized animals, antigen-specific CD8＋ T cells were observed in the livers of recipient HBsAg-Tg animals. Moreover, the three-day pre-treatments with GM-CSF prior to rHBVvac vaccination could significantly eliminate HBsAg-positive hepatocytes, suggesting beneficial therapeutic effects. Therefore, this protocol utilizing GM-CSF as an adjuvant in combination with the rHBVvac vaccine has the potential to become a novel immunotherapy for chronic hepatitis B patients.

铅卤钙钛矿-聚合物复合材料的制备及应用

铅卤钙钛矿纳米晶具有优异的光电性能,在太阳能电池、光电探测和生物成像等领域展现出巨大的发展潜力。然而,铅卤钙钛矿纳米晶自身稳定性差的缺陷制约了其在实际生活中的应用。将铅卤钙钛矿纳米晶嵌入到聚合物中以制备钙钛矿-聚合物复合材料是近年来发展起来的一种有效增强钙钛矿稳定性的策略,特别是致密的聚合物基质赋予钙钛矿纳米晶优异的水稳定性。本文综述了近十年钙钛矿-聚合物复合材料的制备方法及在发光器件和生物医药等领域的应用,探讨了目前仍存在的一些问题和解决方法,并对未来这一领域的发展进行了展望。

A proteomic analysis of Bcl-2 regulation of cell cycle arrest:insight into the mechanisms

B cell lymphoma 2(Bcl-2)is an important antiapoptotic gene that plays a dual role in the maintenance of the dynamic balance between the survival and death of cancer cells.In our previous study,Bcl-2 was shown to delay the G0/G1 to S phase entry by regulating the mitochondrial metabolic pathways to produce lower levels of adenosine triphosphate(ATP)and reactive oxygen species(ROS).However,the detailed molecular mechanisms or pathways by which Bcl-2 regulates the cell cycle remain unknown.Here,we compared the effects of Bcl-2 overexpression with an empty vector control in the NIH3T3 cell line synchronized by serum starvation,and evaluated the effects using proteomic analysis.The effect of Bcl-2 on cell cycle regulation was detected by monitoring Bcl-2 and p27 expression.The result of subsequent proteomic analysis of Bcl-2 overexpressing cells identified 169 upregulated and 120 downregulated proteins with a 1.5-fold change.These differentially expressed proteins were enriched in a number of signaling pathways predominantly involving the ribosome and oxidative phosphorylation,according to the data of Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses.These results indicated that Bcl-2 potentially acts at the translation level to influence proteins or enzymes of the respiratory chain or in the ribosome,and thereby regulates the cell cycle.Additionally,differentially expressed proteins involved in oxidative phosphorylation were determined to account for most of the effects of Bcl-2 on the cell cycle mediated by the mitochondrial pathway investigated in our previous study.These results can provide assistance for additional in-depth studies on the regulation of the cell cycle by Bcl-2.The results of the proteomic analysis determined the mechanism of Bcl-2-dependent delay of the cell cycle progression.In summary,the results of this study provide a novel mechanistic basis for identifying the key proteins or pathways for designing and developing precisely targeted cancer drugs.