The identification of human CD34-negative (CD34(-)) hematopoietic stem cells (HSCs) provides a new concept for the hierarchy in the human HSC compartment. Previous studies demonstrated that CD34(-) ...severe combined immunodeficiency (SCID)-repopulating cells (SRCs) are a distinct class of primitive HSCs in comparison to the well-characterized CD34(+)CD38(-) SRCs. However, the purification level of rare CD34(-) SRCs in 18 lineage marker-negative (Lin(-)) CD34(-) cells (1/1000) is still very low compared with that of CD34(+)CD38(-) SRCs (1/40). As in the mouse, it will be necessary to identify useful positive markers for a high degree of purification of rare human CD34(-) SRCs. Using 18Lin(-)CD34(-) cells, we analyzed the expression of candidate positive markers by flow cytometric analysis. We finally identified CD133 as a reliable positive marker of human CB-derived CD34(-) SRCs and succeeded in highly purifying primitive human CD34(-) HSCs. The limiting dilution analysis demonstrated that the incidence of CD34(-) SRCs in 18Lin(-)CD34(-)CD133(+) cells was 1/142, which is the highest level of purification of these unique CD34(-) HSCs to date. Furthermore, CD133 expression clearly segregated the SRC activities of 18Lin(-)CD34(-) cells, as well as 18Lin(-)CD34(+) cells, in their positive fractions, indicating its functional significance as a common cell surface maker to isolate effectively both CD34(+) and CD34(-) SRCs.
Abstract
This paper reports a new numerical scheme to simulate the radio-frequency (RF) induced RF sheath, which is suitable for a large 3D simulation. In the RF sheath boundary model, the tangential ...component of the electric field (
E
t
) is given by the gradient of a scalar electric field potential. We introduce two additional scalar potentials for the tangential components of the magnetic field, which effectively impose the normal electric displacement (
D
n
) on the plasma sheath boundary condition via in-homogeneous Neumann boundary condition and constrain the tangential electric field on the surface as curl-free (
∇
×
E
t
=
0
). In our approach, the non-linear sheath impedance is formulated as a natural extension of the large thickness (or asymptotic) sheath limit (
D
n
=
0
), allowing for handling both asymptotic and non-linear regimes seamlessly. The new scheme is implemented using the Petra-M finite element method analysis framework and is verified with simulations in the literature. The significance of non-linearity is discussed in various plasma conditions. An application of this scheme to asymptotic RF sheath simulation on the WEST ICRF antenna side limiters is also discussed.
A change of magnetic flux through a circuit induces an electromotive force. By analogy, a recently predicted force that results from the motion of non-uniform spin structures has been termed the ...spin-motive force. Although recent experiments seem to confirm its presence, a direct signature of the spin-motive force has remained elusive. Here we report the observation of a real-time spin-motive force produced by the gyration of a magnetic vortex core. We find a good agreement between the experimental results, theory and micromagnetic simulations, which taken as a whole provide strong evidence in favour of a spin-motive force.
Controlling the position of a magnetic domain wall with electric current may allow for new types of non-volatile memory and logic devices. To be practical, however, the threshold current density ...necessary for domain wall motion must be reduced below present values. Intrinsic pinning due to magnetic anisotropy, as recently observed in perpendicularly magnetized Co/Ni nanowires, has been shown to give rise to an intrinsic current threshold J(th)(0). Here, we show that domain wall motion can be induced at current densities 40% below J(th)(0) when an external magnetic field of the order of the domain wall pinning field is applied. We observe that the velocity of the domain wall motion is the vector sum of current- and field-induced velocities, and that the domain wall can be driven against the direction of a magnetic field as large as 2,000 Oe, even at currents below J(th)(0). We show that this counterintuitive phenomenon is triggered by Walker breakdown, and that the additive velocities provide a unique way of simultaneously determining the spin polarization of current and the Gilbert damping constant.
Summary
Chronic HCV–infected patients tend to have vitamin D deficiency, suggesting that vitamin D supplementation may enhance the efficacy of treatment with pegylated interferon (PEG‐IFN) and ...ribavirin (RBV). We therefore assessed the effects of vitamin D supplementation on viral response to PEG‐IFN/RBV. Eighty‐four patients with HCV genotype 1b were randomized, 42 to oral vitamin D supplementation (1000 IU/day) and 42 to nonsupplementation (control), from week 8 to the end of PEG‐IFN/RBV therapy. The primary end point was undetectable HCV RNA at week 24 (viral response VR). VR rate at week 24 was significantly higher in the vitamin D than in the control group (78.6% vs 54.8% P = 0.037). Adverse events were similar in both groups. When patients were subdivided by IL28B SNP rs8099917 genotype, those with the TT genotype group showed a significantly higher VR rate at week 24 with than without vitamin D supplementation (86.2% vs 63.3% vs P = 0.044). Although patients with the TG/GG genotype, who were relatively resistant to PEG‐IFN treatment, had similar VR rates at week 24 with and without vitamin D supplementation, the decline in viral load from week 8 to week 24 was significantly greater with than without vitamin D supplementation. Multivariate analysis showed that rs8099917 genotype and vitamin D supplementation contributed significantly to VR at week 24. SVR rates were similar in the vitamin D and control groups 64.3% (27/42) vs 50% (21/42), P = 0.19. Vitamin D supplementation may enhance the effects of PEG‐IFN/RBV in HCV genotype 1b–infected patients.
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