Late Cretaceous biota and the Cretaceous-Paleogene(K--Pg)Boundary in Jiayin of Heilongjiang,China

An international cooperative study of the Late Cretaceous biota and non-marine strata including the Cretaceous-Paleogene(K--Pg) boundary in Jiayin near the Heilongjiang River,China during 2002-2010,is summarized in this paper. The strata includes the Upper Cretaceous Yong'ancun-,Taipinglinchang-,Yuliang-zi-,and Furao formations,and the Paleocence Wuyun Formation consisting of Baoshantou Member and a Coalbearing Member. Seven palynological assemblages from Santonian to Paleocene are recognized,which is used for definition of the K--Pg boundary. Through the palynological analysis of three drilled boreholes (XHY-2005,2006,2008) in Xiaoheyan of western Jiayin,the K--Pg boundary is defined within 20. 00-20. 05 m in the borehole XHY-2006 (as a standard boundary) which is just between the top of Furao Formation (late Maasterichtian) and the base of Baishantou Member (early Danian) . These new research results are supported by paleo- magnetic,geochemical and other analyses,also. On the other hand,the presence of eight taxa of Maasterichtian dinosaurs (mostly hadrosaurids) have been recognized by the authors; and two mega-plant assemblages from the Yong'ancun Fm (Santonian) to Taipinglinchang Fm (Campanian) are confirmed. These research a-chievements indicate that the Upper Cretaceous-Paleocene in Jiayin can be well correlated to the strata in the neighboring Zeya-Bureja basin,Russia. The K--Pg boundary definited in Jiayin is the first well documented non-marine K--Pg boundary in China. Also the related paleoclimate,paleoenvironment and the mass extinctions in this area during the Cretaceous-Paleocene transition are also discussed.

弹性散射光谱法可准确鉴别Barrett食管的高度不典型增生与癌变

Background and aims:Endoscopic surveillance of Barrett’s oesophagus currently relies on multiple random biopsies.This approach is time consuming,has a poor diagnostic yield,and significant interobserver variability.Elastic scattering spectroscopy is a real time in vivo optical technique which detects changes in the physical properties of cells.The aim of this study was to assess the potential for elastic scattering to detect high grade dysplasia or cancer within Barrett’s oesophagus.Methods:Elastic scattering spectroscopy measurements collected in vivo were matched with histological specimens taken from identical sites within Barrett’s oesophagus.All biopsies were reviewed by three gastrointestinal pathologists and defined as either “ low risk”(non-dysplastic or low grade dysplasia) or “ high risk”(high grade dysplasia or cancer) .Two different statistical approaches(leave one out and block validation) were used to validate the model.Results:A total of 181 matched biopsy sites from 81 patients,where histopathological consensus was reached,were analysed.There was good pathologist agreement in differentiating high grade dysplasia and cancer from other pathology(kappa = 0.72) .Elastic scattering spectroscopy detected high risk sites with 92% sensitivity and 60% specificity and differentiated high risk sites from inflammation with a sensitivity and specificity of 79%.If used to target biopsies during endoscopy,the number of low risk biopsies taken would decrease by 60% with minimal loss of accuracy.A negative spectroscopy result would exclude high grade dysplasia or cancer with an accuracy of >99.5%.Conclusions:These preliminary results show that elastic scattering spectroscopy has the potential to target conventional biopsies in Barrett’s surveillance saving significant endoscopist and pathologist time with consequent financial savings.This technique now requires validation in prospective studies.