便携式水产品四环素含量检测装置研制

针对水产品四环素残留的便捷化精准检测难题,该研究研制了一种四环素含量检测的便携式直读光电化学装置,并探究了装置用于鱼肉四环素残留检测的可行性。装置分别以LED和STC89C52单片机为激发光源和控制核心,利用设计的光源暗室避免外源光照对检测结果的影响。测试结果表明,LED激发光源的输出信号稳定,装置对于光电流信号的采集具有较好的准确性。进一步基于丝网印刷电极构建光电化学适配体传感器,采用所研制装置对信号进行采集与处理,最终以OLED显示器直接读取抗生素浓度信息。该方法对于四环素检测的线性范围为1×10-11~1×10-8mol/L,检测限为3×10-12mol/L,具有较好的选择性,且对于鱼肉四环素残留检测的回收率为92%~94%,为水产品四环素的精准现场分析提供了新的方法与途径。

New Maikhanellid Shells and Siphogonuchitid Spicule Bundles from the Cambrian Fortunian Stage of South China

Maikhanellids are a distinct group of Cambrian Fortunian small shelly fossils by the capshaped profiles and scaly shell ornamentation.According to the individual shell shape and ornamentation feature types of 50 maikhanellids fossils which were collected from Xixiang botia,we confirmed the family Maikhanellidae content of six genera,which are Maikhanella,Ramenta,Purella,Ramentoides,Yunnannopleura and Mediata.Unlike the halkieriid animals whose shells and spicules are articulated on different body parts,maikhanellids were presumably yielded by siphogonuchitid spicules penetrating the intermediate matrix（the ＂spicule shell＂ hypothesis）,and this is the reason that some researchers treated maikhanellids and co-occurring siphogonuchitids as synonyms.The affinities of Maikhanellids and siphogonuchitids remain debatable.Here,we report three dimensionally phosphatized maikhanellid shells and siphogonuchitid spicule bundles from the Cambrian Fortunian small shell faunas of South China.They differ from all the previously reported maikhanellids and siphogonuchitids,and may represent new types.The intact and smooth surface underneath the partially preserved scales of the shells challenges the ＂spicule-shell＂ hypothesis.The present siphogonuchitid spicules differ from the maikhanellid scales in size,morphology,and.arrangement pattern,thus the spicules might not be derived from the shells.Whether the shells and spicule bundles were articulated on different body parts of the same animals remains unknown.

Xixiang Biota——Another Rare Scientific Window of the Cambrian Explosion

ObjectiveThe Xixiang biota is a specially preserved micro oryctocoenose discovered in the Lower Cambrian Kuanchuanpu member of Dengying Formation at Zhangjiagou section of Xixiang County in southern Shaanxi Province. The Kuanchuanpu member is a set of neritic carbonate sedimentary formation containing phosphorus and silicon. Its lithology is mainly grey massive fine crystalline, dense massive phosphoruscontaining biolithite and flaggy microcrystallinecrystalline dolomitic limestone. It is in a conformable contact with the underlying upper dolomite member of Dengying Formation and a parallel unconformable contact with the overlying Guojiaba Formation. The fossil assemblages of the Xixiang biota could be compared with the microfbssils from the Lower Cambrian Meishucun Stage, and their age is the Early Cambrian Meishucun Stage.

超微粉碎对猕猴桃膳食纤维物化性质和活性的影响

以不同品种猕猴桃膳食纤维为原料,研究其主要成分和单糖组成,同时考察超微粉碎处理对膳食纤维物化特性、α-淀粉酶抑制作用和抗氧化活性的影响。结果表明,不同品种猕猴桃膳食纤维主要成分之间存在着一定差异,在单糖组成方面主要由葡萄糖、木糖和山梨糖构成。超微粉碎处理可显著减小膳食纤维颗粒的粒径,平均粒径为13.22～27.56μm。同时,处理可显著提高样品的持水性、持油性、溶解性和溶胀性,对α-淀粉酶活性的抑制作用均提高了一倍以上,而抗氧化活性也显著上升。