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Turbidites of the Early Cretaceous Lingshandao Formation on Lingshan Island, eastern China, show numerous soft-sediment deformation structures. The turbidites accumulated in a rift basin plain on the distal part of a low-energy fan, together with autochthonous fine-grained sediments that settled from suspension. Occasionally, sets of both types of sediments slumped down the basin slope. The turbidites were studied in two sections. Paleocurrent directions, measured from sole marks at the base of the sandy turbidites, indicate a slope from SE to NW; this is consistent with the dip direction of the axial planes of the major slump folds. Among the numerous types of soft-sediment deformation structures that are present, two types are of special interest because of their specific genesis, viz. rip-up clasts and dome structures. It appears that rapid sedimentation must be considered as the main trigger behind these deformations: the rapid accumulation of particularly the sandy turbidites resulted in overloading of the underlying beds and then consequently in an increase in their pore-water pressure that induced liquefaction and fluidization, which triggered the formation of the rip-up clasts and dome structures. The downslope movement of freshly deposited turbidites after slope failure over the inclined sedimentary surface induced shear stresses, which resulted in the complication of the rip-up clasts and the preferred orientation of some dome structures. Both the dip directions of the axial planes of some of the dome structures and microfolds within the rip-up clasts are consistent with the paleocurrent direction indicated by the sole marks and the slump folds. Les turbidites de la Formation de Lingshandao d'âge crétacé précoce dans l'île Lingshan, en Chine orientale, présentent de nombreuses structures de déformation de sédiments meubles. Les turbidites se sont accumulées dans une plaine de bassin d'effondrement dans la partie distale d'un cône de faible énergie, accompagnées de sédiments a grains fins autochtones déposés à partir de la suspension. De temps à autre, des ensembles des deux types de sédiments ont glissé le long du talus du bassin. Les turbidites ont été étudiées dans deux coupes. Les directions de paléocourant, mesurées à la lumière d'hypoglyphes à la base des turbidites sableuses, indiquent une pente allant du S-E vers le N-O, ce qui concorde avec la direction de pendage des plans axiaux des grands plis de glissement. Parmi les nombreux types de structures de déformation de sédiments meubles présents, deux types sont particulièrement intéressants en raison de leur genèse, à savoir des clastes arrachés et des dômes. Il semble qu'une sédimentation rapide doive être considérée comme étant le principal déclencheur de ces déformations; l'accumulation rapide des turbidites sableuses en particulier s'est traduite par une surcharge des lits sous-jacents et, conséquemment, une augmentation de leur pression interstitielle qui en a induit la liquéfaction et la fluidisation, cette dernière déclenchant la formation des clastes arrachés et des structures en dôme. Le mouvement vers le bas du talus de turbidites fraîchement déposées après la rupture sur la surface sédimentaire inclinée a induit des contraintes de cisaillement, qui se sont traduites par la complication des clastes arrachés et l'orientation préférentielle de certains dômes. Les directions de pendage des plans axiaux de certains dômes et de microplis dans les clastes arrachés s'accordent avec la direction de paléocourant indiquée par les figures basales et les plis de glissement. [Traduit par la Rédaction], Introduction Soft-sediment deformation structures (SSDS; this acronym is used in the present contribution for both singular and plural) include a wide range of sediment deformations with various morphologies; they are [...]

Experiments have shown that cholesterol influences the membrane permeability of small molecules, amino acids, and cell-penetrating peptides. However, their exact translocation mechanisms under the influence of cholesterol remain poorly understood. Given the practical importance of cell-penetrating peptides and the existence of varied cholesterol contents in different cell types, it is necessary to examine the permeation of amino acids in cholesterol-containing membranes at atomic level of details. Here, bias-exchange metadynamics simulations were employed to investigate the molecular mechanism of the membrane permeation of two amino acids Arg and Trp important for cell-penetrating peptides in the presence of different concentrations of cholesterol. We found that the free energy barrier of Arg+ (the protonated form) permeation increased linearly as the cholesterol concentration increased, whereas the barrier of Trp permeation had a rapid increase from 0 mol. % to 20 mol. % cholesterol-containing membranes and nearly unchanged from 20 mol. % to 40 mol. % cholesterol-containing membranes. Arg0 becomes slightly more stable than Arg+ at the center of the dipalmitoylphosphatidylcholine (DPPC) membrane with 40 mol. % cholesterol concentrations. As a result, Arg+ has a similar permeability as Trp at 0 mol. % and 20 mol. % cholesterol, but a significantly lower permeability than Trp at 40 mol. % cholesterol. This difference is caused by the gradual reduction of water defects for Arg+ as the cholesterol concentration increases but lack of water defects for Trp in cholesterol-containing membranes. Strong but different orientation dependence between Arg+ and Trp permeations is observed. These results provide an improved microscopic understanding of amino-acid permeation through cholesterol-containing DPPC membrane systems. [ABSTRACT FROM AUTHOR]