Biflavonoids are superior to monoflavonoids in inhibiting amyloid-β toxicity and fibrillogenesis via accumulation of nontoxic oligomer-like structures

Polymerization of monomeric amyloid-β peptides (Aβ) into soluble oligomers and insoluble fibrils is one of the major pathways triggering the pathogenesis of Alzheimer's disease (AD). Using small molecules to prevent the polymerization of Aβ peptides can, therefore, be an effective therapeutic strategy for AD. In this study, we investigate the effects of mono- and biflavonoids in Aβ42-induced toxicity and fibrillogenesis and find that the biflavonoid taiwaniaflavone (TF) effectively and specifically inhibits Aβ toxicity and fibrillogenesis. Compared to TF, the monoflavonoid apigenin (AP) is less effective and less specific. Our data show that differential effects of the mono- and biflavonoids in Aβ fibrillogenesis correlate with their varying cytoprotective efficacies. We also find that other biflavonoids, namely, 2',8'-biapigenin, amentoflavone, and sumaflavone, can also effectively inhibit Aβ toxicity and fibrillogenesis, implying that the participation of two monoflavonoids in a single biflavonoid molecule enhances their activity. Biflavonoids, while strongly inhibiting Aβ fibrillogenesis, accumulate nontoxic Aβ oligomeric structures, suggesting that these are off-pathway oligomers. Moreover, TF abrogates the toxicity of preformed Aβ oligomers and fibrils, indicating that TF and other biflavonoids may also reduce the toxicity of toxic Aβ species. Altogether, our data clearly show that biflavonoids, possibly because of the possession of two Aβ binders separated by an appropriate size linker, are likely to be promising therapeutics for suppressing Aβ toxicity.     

灵井许昌人遗址第5层细石核工艺

本文研究的细石核出自灵井"许昌人"遗址第5层,该层为桔黄色粉细砂,2008-2013年发掘,出土细石核82件,其他还有与之相关的材料。该层碳十四年龄为13402±406BP。细石核素材一般为燧石质的石片、小砾石等。根据其毛坯形状、细石叶剥离进度等的差异,形成了角锥形、柱形、圆锥形等各种形状。在剥离石叶过程中,曾运用过台面修理、工作面上端(细石叶头部)修正、台面更新、台面转移等调整手法。灵井石器工业的细石叶工艺是一种以角锥形(型)细石核为主的技术。通过对比,灵井与华北各地的同类细石核大小尺寸接近,与本省临近的大岗、李家沟等细石器遗址应属相同或相近技术传统的细石叶工艺。     

化学杂交剂对灌浆期小麦源流库的影响

以大穗小麦品种SN05-3和多穗小麦SN02-3为试验材料,研究了化学杂交剂BAU-9403对灌浆期小麦库、源、流的影响.结果表明,BAU-9403诱导的小麦雄性不育率大于95%,异交结实率高于92.5%;BAU-9403能够显著降低旗叶叶绿素含量和提高其净光合速率;喷药处理的干物质日生产量,茎、叶、鞘的干物质转移量及其输出率和转换率均下降;喷药处理籽粒饱满度平均减少0.222,平均灌浆速率降低0.306g/1000 grains·d-1,灌浆持续期平均缩短6.03d.BAU-9403处理的SN05-3净光合速率增加幅度、叶绿素含量及茎中干物质转移量、输出率和转换率下降幅度均高于SN02-3,而叶中干物质转移量下降幅度和鞘中的干物质输出率却低于SN02-3;SN05-3的灌浆持续期缩短幅度明显大于SN02-3,而其灌浆速率下降的程度小于SN02-3.综合分析表明,BAU-9403能够影响灌浆期小麦的光合生理特性,破坏库、源之间的平衡关系,使干物质积累和转运不畅,导致粒重下降,且品种间的反应存在差异.     

A Durable Alternative for Proton‐Exchange Membranes: Sulfonated Poly(Benzoxazole Thioether Sulfone)s

To develop a durable proton‐exchange membrane (PEM) for fuel‐cell applications, a series of sulfonated poly(benzoxazole thioether sulfone)s ( SPTESBOs) are designed and synthesized, with anticipated good dimensional stability (via acid–base cross linking), improved oxidative stability against free radicals (via incorporation of thioether groups), and enhanced inherent stability (via elimination of unstable end groups) of the backbone. The structures and the degree of sulfonation of the copolymers are characterized using Fourier‐transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy (¹H NMR and ¹⁹F NMR). The electrochemical stabilities of the monomers are examined using cyclic voltammetry in a typical three‐electrode cell configuration. The physicochemical properties of the membranes vital to fuel‐cell performance are also carefully evaluated under conditions relevant to fuel‐cell operation, including chemical and thermal stability, proton conductivity, solubility in different solvents, water uptake, and swelling ratio. The new membranes exhibit low dimensional change at 25°C to 90°C and excellent thermal stability up to 250°C. Upon elimination of unstable end groups, the co‐polymers display enhanced chemical resistance and oxidative stability in Fenton's test. Further, the SPTESBO‐HFB‐60 (HFB‐60=hexafluorobenzene, 60 mol% sulfone) membrane displays comparable fuel‐cell performance to that of an NRE 212 membrane at 80°C under fully humidified condition, suggesting that the new membranes have the potential to be more durable but less expensive for fuel‐cell applications.     

易与花斑糠疹混淆的融合性网状乳头瘤病合并黑棘皮病1例

融合性网状乳头瘤病为一种少见的原因不明的皮肤病,不易诊断。多见于青少年,好发于躯干部和腋窝,为褐色鳞屑性斑片或斑块。临床易误诊而被延误治疗。报告1例融合性网状乳头瘤病合并黑棘皮病,曾被多次拟诊为花斑糠疹,有较典型的临床表现和组织病理改变。口服及外用异维A酸治疗有效。     

炭疽芽胞杆菌(Bacillus anthracis)检测质粒的构建及其应用

根据炭疽芽胞杆菌(Bacillus anthracis)毒性质粒pX01和pX02上的2个毒力相关基因cya和capA的序列特点,以pIJ2925为出发载体,采用一步重叠延伸PCR技术(One-step Overlap Extension PCR,简称OOE-PCR)构建了包含cya基因和capA基因保守区DNA片段的炭疽检测质粒pBIB2006。采用复合PCR对模拟炭疽危险品进行分析,结果表明pBIB2006可以为炭疽芽胞杆菌的检测提供准确、安全和方便的阳性参照品,从而为检测炭疽芽胞杆菌和炭疽芽胞杆菌灭活疫苗提供了便利。     

Atherosclerosis,Oxidation and Endometriosis

Endometriosis affects younger women of childbearing age. Atherosclerosis is considered as a disease of the old and increases with the ageing process. Both diseases are characterized by the increased presence of activated macrophages and associated increases in growth promoting activity and the production of inflammatory cytokines. In this review, we propose that oxidative stress and the presence of forms of oxidized low-density lipoprotein (LDL) might contribute to both Atherosclerosis and Endometriosis.