Reclassification and distribution patterns of discovered oils in theDongying Depression, Bohai Bay Basin, China

The Dongying Depression is an important petrolifeous province,with diverse source rocks and complex petroleum distribution patterns.A total of 32 crude oils were analyzed by the gas chromatographyemass spectrometry and isotopic compositions to better understanding the petroleum systems in the study area.Three oil types were classified by hierarchical cluster analyses.Type I and II oils have closely correlation with the discovered source rocks,which have been confirmed to be mainly derived from the lower third and upper forth member of the Eocene Shahejie Formation source rocks(Es3^(L) and Es4^(U)),respectively.Obviously,type III oils contain abundant gammacerane,tricyclic terpanes and C_(29) steranes and have lower values of δ13C than type I and II oils,indicating a completely different source rock and biological origins.Until recently,type III oils fail to match any of the discovered source rock,which contains main contribution of aquatic organism or/and bacteria inputs.In addition,the spacial distribution of these three oil types were discussed.Type I oils mainly distributed in the Es3 and Es4 reservoirs that closed to the generative kitchens.Type II oils occurred in the Es4 reservoirs in the sourthern slope of the depression,which probably caused by lateral migration along the horizontal fractures and sandstone layers within the Es4 interval.Differently,type III oils in the sourthern slope of the depression were mainly discovered in the Eocene Kongdian or Ordocician reservoirs,which suggests great exploration potential of deep underlying strata.

Retinal vessel oxygen saturation in healthy subjects and early branch retinal vein occlusion

AIM： To measure the retinal oxygen saturation in healthy subjects and early branch retinal vein occlusion（BRVO） in Chinese population.METHODS： The retinal vessel oxygen saturation of the healthy subjects and BRVO patients were measured by a noninvasive retinal oximeter（Oxymap ehf.,Reykjavik,Iceland）.RESULTS： The study included 22 patients with unilateral BRVO（mean age： 55.1±8.8y） in the study group and 91 healthy participants（mean age： 37.5±14.0y） in the control group.In the healthy individuals,mean arterial and venous oxygen saturation were significantly（P〈0.001）higher in the superior nasal quadrant（98.5%±10.1%and 57.3%±8.7%,respectively） than in the inferior nasal quadrant（94.2%±9.0% and 54.1%±9.6%,respectively）,followed by the superior temporal quadrant（89.1%±10.1%and 51.9%±8.9%,respectively） and the inferior temporal quadrant（86.4%±9.4% and 46.6%±9.6%,respectively）.In patients with ischemic BRVO,arterial oxymetric values were significantly higher and venous measurements significantly lower for the affected vessel（107.5%±9.7% and46.4%±14.2%,respectively） than the unaffected vessel in the same eye（99.2%±12.2% and 55.5%±7.9%,respectively）and as compared to the vessel in the unaffected fellow eye（93.1%±6.9% and 55.7%±6.8%）（P=0.005 and P=0.02,respectively）.In the patients with non-ischemic BRVO,mean venous oxygen saturation was lower in the affected vein（39.8%±12.2%） than in the unaffected vessels of the same eye（50.8%±10.5%） and in the fellow eye（58.21%±5.7%）（P=0.03）.Mean arterial oxygen saturation did not differ significantly（P=0.42） between all three groups.CONCLUSION： In patients with BRVO,the venous oxygen saturation in the affected vessels is decreased potentially due to decreased blood velocity and flow.Interestingly,thearterial oxygen saturation in eyes with ischemic BRVO is increased in the affected arteries.