Depositional process of hyperpycnal flow deposits:A case study on Lower Cretaceous Sangyuan outcrop in the Luanping Basin,Northeast China

Sedimentary process research is of great significance for understanding the distribution and characteristics of sediments.Through the detailed observation and measurement of the Sangyuan outcrop in Luanping Basin,this paper studies the depositional process of the hyperpycnal flow deposits,and divides their depositional process into three phases,namely,acceleration,erosion and deceleration.In the acceleration phase,hyperpycnal flow begins to enter the basin nearby,and then speeds up gradually.Deposits developed in the acceleration phase are reverse.In addition,the original deposits become unstable and are taken away by hyperpycnal flows under the eroding force.As a result,there are a lot of mixture of red mud pebbles outside the basin and gray mud pebbles within the basin.In the erosion phase,the reverse deposits are eroded and become thinner or even disappear.Therefore,no reverse grading characteristic is found in the proximal major channel that is closer to the source,but it is still preserved in the middle branch channel that is far from the source.After entering the deceleration phase,normally grading deposits appear and cover previous deposits.The final deposits in the basin are special.Some are reverse,and others are normal.They are superimposed with each other under the action of hyperpycnal flow.The analysis of the Sangyuan outcrop demonstrates the sedimentary process and distribution of hyperpycnites,and reasonably explain the sedimentary characteristics of hyperpycnites.It is helpful to the prediction of oil and gas exploration targets in gravity flow deposits.

Spheroids of Endothelial Cells and Vascular Smooth Muscle Cells Promote Cell Migration in Hyaluronic Acid and Fibrinogen Composite Hydrogels

Cell migration plays a pivotal role in many pathological and physiological processes.So far,most of the studies have been focused on 2-dimensional cell adhesion and migration.Herein,the migration behaviors of cell spheroids in 3D hydrogels obtained by polymerization of methacrylated hyaluronic acid(HA-MA)and fibrinogen(Fg)with different ratios were studied.The Fg could be released to the medium gradually along with time prolongation,achieving the dynamic change of hydrogel structures and properties.Three types of cell spheroids,i.e.,endothelial cell(EC),smooth muscle cell(SMC),and EC-SMC spheroids,were prepared with 10,000 cells in each,whose diameters were about 343,108,and 224μm,respectively.The composite hydrogels with an intermediate ratio of Fg allowed the fastest 3D migration of cell spheroids.The ECs-SMCs migrated longest up to 3200μm at day 14,whereas the SMC spheroids migrated slowest with a distance of only~400μm at the same period of time.The addition of free RGD or anti-CD44 could significantly reduce the migration distance,revealing that the cell-substrate interactions take the major roles and the migration is mesenchymal dependent.Moreover,addition of anti-N-cadherin and MMP inhibitors also slowed down the migration rate,demonstrating that the degradation of hydrogels and cell-cell interactions are also largely involved in the cell migration.RT-PCR measurement showed that expression of genes related to cell adhesion and antiapoptosis,and angiogenesis was all upregulated in the EC-SMC spheroids than single EC or SMC spheroids,suggesting that the use of composite cell spheroids is more promising to promote cell-substrate interactions and maintenance of cell functions.