104 research outputs found
Individual motions of red blood cells in high-hematocrit blood flowing in a microchannel with complex geometries
Blood flow in a microchannel with complex geometries has been
investigated to develop biomedical microdevices (e.g. Faivre et al.,
2006) or to understand pathology in small vessels, such as lacunar
infarcts. In a small channel, say 100 μm in diameter, the blood is no
longer assumed to be a homogeneous fluid because the size of the red
blood cells (RBCs) cannot be neglected compared to the generated
flow field (the diameter of a RBC is about 8 μm). In such a case, we
must treat the blood as a multiphase fluid, and investigate the motion
of individual cells in discussing the flow field. In this study, we
investigated the motion of RBCs in a microchannel with stenosis or
bifurcation using a confocal micro-PTV system. We measured
individual trajectories of RBCs under high Hct conditions (up to 20%),
when the interactions between RBCs become significant. We discuss
the effect of Hct on the flow field and cell-free layers, as well as the
effect of deformability of RBCs on the cell-free layer thickness by
hardening RBCs using a glutaraldehyde treatment
Red blood cell motions in high-hematocrit blood flowing through a stenosed microchannel
We investigated the behaviour of red blood cells (RBCs) in a micro-channel with stenosis by using a confocal micro-PIV system. We could successfully measure individual trajectories of RBCs in a concentrated suspension up to 20% hematocrit (Hct). The results show that the trajectories of healthy RBCs become asymmetric before and after the stenosis, though trajectories of tracer particles in pure water are almost symmetric. The asymmetry is larger in a 10% Hct case than in a 20% Hct case. We also
investigated the effect of deformability of RBCs on the trajectories by hardening RBCs by glutarardehyde treatment. The results indicate that the deformability is the key factor in the asymmetry of trajectories and
the thickness of cell-free layer. We think that the present results give fundamental knowledge for better understanding blood flow in microcirculations
Blood flow in microchannel with stenosis measured by a confocal micro PTV system
Blood in microcircualtion is not a homogenous fluid
but the suspension of Red Blood Cells(RBC). So
individual RBCs behavior is essential to get good
comprehension about the blood flow in
microcirculation. In this study we observe the RBCs
behavior through the stenosis by using confocal-micro-
PTV system. And we can observe the difference of the
cell free layer thickness according to Hct
Synergistic Formation of Radicals by Irradiation with Both Vacuum Ultraviolet and Atomic Hydrogen: A Real-Time In Situ Electron Spin Resonance Study
We report on the surface modification of polytetrafluoroethylene (PTFE) as an
example of soft- and bio-materials that occur under plasma discharge by
kinetics analysis of radical formation using in situ real-time electron spin
resonance (ESR) measurements. During irradiation with hydrogen plasma,
simultaneous measurements of the gas-phase ESR signals of atomic hydrogen and
the carbon dangling bond (C-DB) on PTFE were performed. Dynamic changes of the
C-DB density were observed in real time, where the rate of density change was
accelerated during initial irradiation and then became constant over time. It
is noteworthy that C-DBs were formed synergistically by irradiation with both
vacuum ultraviolet (VUV) and atomic hydrogen. The in situ real-time ESR
technique is useful to elucidate synergistic roles during plasma surface
modification.Comment: 14 pages, 4 figure
Friend of Prmt1, FOP is a novel component of the nuclear SMN complex isolated using biotin affinity purification
SMN (survival motor neuron protein) complexes are essential for the biogenesis of uridine-rich small nuclear ribonucleoproteins (UsnRNPs). During the biogenesis, the SMN complexes bound to UsnRNPs are transported from the cytoplasm to the nucleus, and moved to Cajal body (bodies)/Gems (Cajal/Gems) where the SMN complexes- UsnRNPs are subjected to additional chemical modifications and dissociated to the SMN complexes and the mature UsnRNPs. Although the mature UsnRNPs are assembled into spliceosome with newly transcribed pre-mRNA in the perichromatin fibrils at the chromatin, the role of the dissociated nuclear SMN complexes remains undetermined. In this study, we identified Friend of Prmt1 (FOP; chromatin target of Prmt1, CHTOP; C1orf77) as a novel component of the nuclear SMN complexes by the biotin affinity purification, coupled with the mass spectrometry-based protein identification. FOP was associated with SMN, Gemines 2, 3, 4, 6, and 8, unrip, and fragile X mental retardation 1 protein (FMR1), as well as with U5and U6 snRNAs in the nucleus, but not with Sm proteins, Gemin5, coilin, and U1 and U2snRNAs. Using the quantitative proteomic method with SILAC coupled with RNA interference, we also showed that FOP is required for the association of the SMN complexes with hnRNPs, histone proteins, and various RNA-binding proteins. It is reported that FOP localizes mainly in the nuclear speckles, binds chromatin, and plays a role in mRNA transcriptional regulation. Our present data suggest that the nuclear SMN complex containing FOP participates in the process of mRNA post-transcriptional regulation
Mice with Asthma Are More Resistant to Influenza Virus Infection and NK Cells Activated by the Induction of Asthma Have Potentially Protective Effects
Prognostic significance of 5-fluorouracil metabolism-relating enzymes and enhanced chemosensitivity to 5-fluorouracil by 5-chloro 2,4-dihydroxy-pyridine in urothelial carcinoma
The mass determination of TOI-519 b: a close-in giant planet transiting a metal-rich mid-M dwarf
We report the mass determination of TOI-519 b, a transiting substellar object
around a mid-M dwarf. We carried out radial velocity measurements using Subaru
/ InfraRed Doppler (IRD), revealing that TOI-519 b is a planet with a mass of
. We also find that the host star is metal
rich ( dex) and has the lowest effective
temperature ( K) among all stars hosting known
close-in giant planets based on the IRD spectra and mid-resolution infrared
spectra obtained with NASA Infrared Telescope Facility / SpeX. The core mass of
TOI-519 b inferred from a thermal evolution model ranges from to
, which can be explained by both the core accretion and disk
instability models as the formation origins of this planet. However, TOI-519 is
in line with the emerging trend that M dwarfs with close-in giant planets tend
to have high metallicity, which may indicate that they formed in the core
accretion model. The system is also consistent with the potential trend that
close-in giant planets around M dwarfs tend to be less massive than those
around FGK dwarfs.Comment: 10 pages, 5 figures. Accepted for publication in PAS
Phosphoinositide 3-Kinaseγ Controls the Intracellular Localization of CpG to Limit DNA-PKcs-Dependent IL-10 Production in Macrophages
Synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG) stimulate innate immune responses. Phosphoinositide 3-kinase (PI3K) has been implicated in CpG-induced immune activation; however, its precise role has not yet been clarified. CpG-induced production of IL-10 was dramatically increased in macrophages deficient in PI3Kγ (p110γ−/−). By contrast, LPS-induced production of IL-10 was unchanged in the cells. CpG-induced, but not LPS-induced, IL-10 production was almost completely abolished in SCID mice having mutations in DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Furthermore, wortmannin, an inhibitor of DNA-PKcs, completely inhibited CpG-induced IL-10 production, both in wild type and p110γ−/− cells. Microscopic analyses revealed that CpG preferentially localized with DNA-PKcs in p110γ−/− cells than in wild type cells. In addition, CpG was preferentially co-localized with the acidic lysosomal marker, LysoTracker, in p110γ−/− cells, and with an early endosome marker, EEA1, in wild type cells. Over-expression of p110γ in Cos7 cells resulted in decreased acidification of CpG containing endosome. A similar effect was reproduced using kinase-dead mutants, but not with a ras-binding site mutant, of p110γ. Thus, it is likely that p110γ, in a manner independent of its kinase activity, inhibits the acidification of CpG-containing endosomes. It is considered that increased acidification of CpG-containing endosomes in p110γ−/− cells enforces endosomal escape of CpG, which results in increased association of CpG with DNA-PKcs to up-regulate IL-10 production in macrophages
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