Bone marrow microenvironment: The guardian of leukemia stem cells

Bone marrow microenvironment (BMM) is the main sanctuary of leukemic stem cells (LSCs) and protects these cells against conventional therapies. However, it may open up an opportunity to target LSCs by breaking the close connection between LSCs and the BMM. The elimination of LSCs is of high importance, since they follow cancer stem cell theory as a part of this population. Based on cancer stem cell theory, a cell with stem cell-like features stands at the apex of the hierarchy and produces a heterogeneous population and governs the disease. Secretion of cytokines, chemokines, and extracellular vesicles, whether through autocrine or paracrine mechanisms by activation of downstream signaling pathways in LSCs, favors their persistence and makes the BMM less hospitable for normal stem cells. While all details about the interactions of the BMM and LSCs remain to be elucidated, some clinical trials have been designed to limit these reciprocal interactions to cure leukemia more effectively. In this review, we focus on chronic myeloid leukemia and acute myeloid leukemia LSCs and their milieu in the bone marrow, how to segregate them from the normal compartment, and finally the possible ways to eliminate these cells.

An experimental approach for measuring carbon dioxide diffusion coefficient in water and oil under supercritical conditions

Several direct or indirect approaches have been proposed to measure diffusion coefficient of gases into liquids.The main complexity of indirect techniques such as pressure decay method is interpreting early pressure-time data which strongly affected by incubation period effect or convective instability.In the current approach,accurate apparatus and precise experimental setup including a high pressure and temperature PVT cell,a high precision Sanchez pump,heating and recording sub-system are implemented and a novel data analysis procedure is applied to modify pressure decay method.The effect of incubation period is reduced remarkably and diffusion coefficient of carbon dioxide in water in wide range of pressures and temperatures is determined and the effects of temperature,pressure and carbon dioxide phase alteration from gas to supercritical are investigated and the value of uncertainty is estimated.Furthermore,diffusion coefficient of CO_(2) and methane in an oil sample from one of the Iranian southwest oil formations is determined precisely using the experimental approach while no incubation period is detected.The results showed that incubation period duration decreases with increasing diffusion coefficient.Additionally,when CO_(2) state is gas,rate of increasing diffusion coefficient with pressure is decreased with temperature and when CO_(2) state is supercritical,the rate of increasing diffusion coefficient with pressure is decreased significantly.

Studying the effect of surfactant assisted low-salinity water flooding on clay-rich sandstones

Sandstone reservoirs often contain clay particles that can cause damage and reduce permeability during low-salinity water flooding.In this study,the effect of surfactants on fine migration in clay-rich sandstones and its impact on oil recovery was investigated.First,the impact of surfactants on interparticle forces in fine-matrix,fine-fine,and oil-matrix systems was modeled.The results showed that both CTAB(cetyltrimethyl ammonium bromide)and QS(quillaja saponin)cause EDL compaction,weakening the repulsive forces.However,SDS(sodium dodecyl sulfate)and TX(triton X-100)do not affect the EDL.Next,the effect of surfactants on IFT reduction and wettability alteration was experimentally investigated.All surfactants reduced IFT due to the surface excessive concentration mechanism.The wettability alteration experiment illustrated that although QS and CTAB compact EDL around oil and matrix particles leading to attraction force augmentation,they both alter wettability through adsorption on matrix and carboxylic groups present in crude oil,respectively.Surfactant aqueous solutions were then injected into various clay-rich sandstone sanpacks,which resulted in increased oil recovery.However,the mechanisms leading to enhanced oil recovery variedby surfactant type.CTAB increased recovery by 10%through IFT reduction and wettability alteration,while SDS and TX increased recovery by 12%and 9%,respectively,through wettability alteration and extreme fine migration.In contrast,partial fine migration in the QS flooding experiment reached a recovery increase of 18%.Permeability trends through experiments were also recorded.During CTAB injection,permeability did not reduce,while QS aqueous solution reduced rock permeability to 5 m D.SDS and TX reduced the magnitude of permeability to 2 m D.In conclusion,this study demonstrates that surfactants can effectively improve oil recovery in clay-rich sandstones by altering the interparticle forces,reducing IFT,and changing wettability.The results suggest that the type of surfactant used should be carefully selected to achieve the desired recovery increase without affecting the permeability of the reservoir.

A laboratory study of a novel bio-based nonionic surfactant to mitigate clay swelling

This study reports the applicability of quillaja saponin(QS)as a vigorous and environmentally friendly shale swelling inhibitor.QS is a natural surfactant,which is extracted from herbal sources.The inhibition strength of this surfactant was assessed through various experiments,such as sedimentation,inhibition,filtration,particle size,Scanning Electron Microscope(SEM)images,and cutting recovery.Data obtained from these tests illustrated that QS greatly inhibits clays from swelling.The optimal concentration for QS in this intend was 10 g/L.Compatibility of this surfactant with other common additives was also investigated,which showed that it is totally compatible.Finally,the potential inhibition mechanism was assessed through thermal gravimetric analysis(TGA),zeta potential,and contact angle measurement experiments.Surface coating,and wettability alteration of clay particles to the oil-wet state was recognized as the most probable mechanism.