.
We propose a model describing liquid-solid phase coexistence in mixed lipid membranes by including explicitly the occurrence of a rippled phase. For a single component membrane, we employ a ...previous model in which the membrane thickness is used as an order parameter. As function of temperature, this model properly accounts for the phase behavior of the three possible membrane phases: solid, liquid and the rippled phase. Our primary aim is to explore extensions of this model to binary lipid mixtures by considering the composition dependence of important model parameters. The obtained phase diagrams show various liquid, solid and rippled phase coexistence regions, and are in quantitative agreement with the experimental ones for some specific lipid mixtures.
The SH2 domain-containing inositol 5'-phosphatase (SHIP) is crucial in hematopoietic development. To evaluate the possible tumor suppressor role of the SHIP gene in myeloid leukemogenesis, we ...examined primary leukemia cells from 30 acute myeloid leukemia (AML) patients, together with eight myeloid leukemia cell lines. A somatic mutation at codon 684, replacing Val with Glu, was detected in one patient, lying within the signature motif 2, which is the phosphatase active site. The results of an in vitro inositol 5'-phosphatase assay revealed that the mutation reduced catalytic activity of SHIP. Leukemia cells with the mutation showed enhanced Akt phosphorylation following IL-3 stimulation. K562 cells transfected with the mutated SHIP-V684E cDNA showed a growth advantage even at lower serum concentrations and resistance to apoptosis induced by serum deprivation and exposure to etoposide. These results suggest a possible role of the mutated SHIP gene in the development of acute leukemia and chemotherapy resistance through the deregulation of the phosphatidylinositol-3,4,5-triphosphate (PI(3,4,5)P3)/Akt signaling pathway. This is the first report of a mutation in the SHIP gene in any given human cancer, and indicates the need for more attention to be paid to this gene with respect to cancer pathogenesis.
Non-linear rheology of lamellar liquid crystals Lu, C. -Y. D.; Chen, P.; Ishii, Y. ...
The European physical journal. E, Soft matter and biological physics,
2008/1, Letnik:
25, Številka:
1
Journal Article
Recenzirano
Odprti dostop
.
We measure the non-linear relation between the shear stress and shear rate in the lyotropic lamellar phase of C
12
E
5
/water system. The measured shear thinning exponent changes with the ...surfactant concentration. A simple rheology theory of a lamellar or smectic phase is proposed with a prediction
∼ σ
3/2
, where
is the shear rate and σ is the shear stress. We consider that the shear flow passed through the defect structure causes the main dissipation. As the defect line density varies with the shear rate, the shear thinning arises. The defect density is estimated by the dynamic balance between the production and annihilation processes. The defect production is caused by the shear-induced layer undulation instability. The annihilation occurs through the shear-induced defect collision process. Further flow visualization experiment shows that the defect texture correlates strongly with the shear thinning exponent.
Purpose: Conventional gamma‐ray detector, PET and SPECT, have the limitation of energy. These limitations are major problems of studying for a new medical imaging. Therefore, we have developed the ...new imaging detector which is an electron‐tracking Compton camera (ETCC). We show results of the update ETCC system and show the imaging Result of 95m‐Tc which is one of the targets for new imaging reagents. Methods: The ETCC has a wide energy dynamic range and wide field of view. Also the ETCC can detect recoil‐electron tracks which are generated from Compton scattering. We have developed the new ETCC system which have been modified the logic of catching the electron tracks and have better performance compared with old system. The 99m‐Tc is the most important radioisotopes which are used in nuclear medicine. However, the lifetime of the 99m‐Tc is 6 hours, it may not be possible to use imaging reagent for using antibody reaction because of accumulation time. The technetium, however, have many isotopes and many energy peaks. If we can reconstruct gamma rays which have various energy peaks, imaging technology for nuclear medicine will progress. The 95m‐Tc (204, 582, 835 keV ) is one of the targets for a new imaging reagent. In this presentation, we show the new ETCC system performance and 95m‐Tc imaging results. Results: ETCC achieved a wide energy dynamic range (200–1300keV) and wide field of view. We could catch the recoil electron tracks clearly using new ETCC system, and we succeeded in imaging of the 95m‐Tc. Conclusion: We have developed the ETCC for new medical imaging device and succeeded in imaging of the 95m‐Tc. We started to develop the ETCC which can image the mouse within 30 min. Thus, this detector has the possibility of new medical imaging.
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