37,720 research outputs found
Z-stack U1 glycoRNA with CT-B
No full textHL-60 cells were stained with U1 glycoRNA ARPLA and CT-B (for lipid raft staining).
Z-stack images were collected with laser scanning confocal microscopy ZEISS 710 (63 x oil-immersion objective) and laser lines (ex/em 561 nm/ 566-651 nm and 633 nm / 638-755 nm). 22 slices (in total 10.421 µm) were collected, and the images were processed with ZEN software.
The data were shown in raw data, in the z-stack gallery, in max intensity projection, or in Ortho projection. The data was exported in movie format.</p
The influence of inlet velocity profile on predicted flow in type B aortic dissection
No full textIn order for computational fluid dynamics to provide quantitative parameters to aid in the clinical assessment of type B aortic dissection, the results must accurately mimic the hemodynamic environment within the aorta. The choice of inlet velocity profile (IVP) therefore is crucial; however, idealised profiles are often adopted, and the effect of IVP on hemodynamics in a dissected aorta is unclear. This study examined two scenarios with respect to the influence of IVP—using (a) patient-specific data in the form of a three-directional (3D), through-plane (TP) or flat IVP; and (b) non-patient-specific flow waveform. The results obtained from nine simulations using patient-specific data showed that all forms of IVP were able to reproduce global flow patterns as observed with 4D flow magnetic resonance imaging. Differences in maximum velocity and time-averaged wall shear stress near the primary entry tear were up to 3% and 6%, respectively, while pressure differences across the true and false lumen differed by up to 6%. More notable variations were found in regions of low wall shear stress when the primary entry tear was close to the left subclavian artery. The results obtained with non-patient-specific waveforms were markedly different. Throughout the aorta, a 25% reduction in stroke volume resulted in up to 28% and 35% reduction in velocity and wall shear stress, respectively, while the shape of flow waveform had a profound influence on the predicted pressure. The results of this study suggest that 3D, TP and flat IVPs all yield reasonably similar velocity and time-averaged wall shear stress results, but TP IVPs should be used where possible for better prediction of pressure. In the absence of patient-specific velocity data, effort should be made to acquire patient’s stroke volume and adjust the applied IVP accordingly
Qualitative and Quantitative Assessments of Blood Flow on Tears in Type B Aortic Dissection With Different Morphologies
No full textObjective: The interactions between aortic morphology and hemodynamics play a key role in determining type B aortic dissection (TBAD) progression and remodeling. The study aimed to provide qualitative and quantitative hemodynamic assessment in four different TBAD morphologies based on 4D flow MRI analysis. Materials and Methods: Four patients with different TBAD morphologies underwent CT and 4D flow MRI scans. Qualitative blood flow evaluation was performed by visualizing velocity streamlines and flow directionality near the tears. Quantitative analysis included flow rate, velocity and reverse flow index (RFI) measurements. Statistical analysis was performed to evaluate hemodynamic differences between the true lumen (TL) and false lumen (FL) of patients. Results: Qualitative analysis revealed blood flow splitting near the primary entry tears (PETs), often causing the formation of vortices in the FL. All patients exhibited clear hemodynamic differences between TL and FL, with the TL generally showing higher velocities and flow rates, and lower RFIs. Average velocity magnitude measurements were significantly different for Patient 1 (t = 5.61, p = 0.001), Patient 2 (t = 3.09, p = 0.02) and Patient 4 (t = 2.81, p = 0.03). At follow-up, Patient three suffered from left renal ischemia because of FL collapse. This patient presented a complex morphology with two FLs and marked flow differences between TL and FLs. In Patient 4, left renal artery malperfusion was observed at the 32-months follow-up, due to FL thrombosis growing after PET repair. Conclusion: The study demonstrates the clinical feasibility of using 4D flow MRI in the context of TBAD. Detailed patient-specific hemodynamics assessment before treatment may provide useful insights to better understand this pathology in the future
Evaluation and verification of patient-specific modelling of type B aortic dissection
No full textQuantitative assessment of the complex hemodynamic environment in type B aortic dissection (TBAD) through computational fluid dynamics (CFD) simulations can provide detailed insights into the disease and its progression. As imaging and computational technologies have advanced, methodologies have been developed to increase the accuracy and physiological relevance of CFD simulations. This study presents a patient-specific workflow to simulate blood flow in TBAD, utilising the maximum amount of in vivo data available in the form of CT images, 4D-flow MRI and invasive Doppler-wire pressure measurements, to implement the recommended current best practice methodologies in terms of patient-specific geometry and boundary conditions. The study aimed to evaluate and verify this workflow through detailed qualitative and quantitative comparisons of the CFD and in vivo data. Based on data acquired from five TBAD patients, a range of essential model inputs was obtained, including inlet flow waveforms and 3-element Windkessel model parameters, which can be utilised in further studies where in vivo flow data is not available. Local and global analysis showed good consistency between CFD results and 4D-MRI data, with the maximum velocity in the primary entry tear differing by up to 0.3 m/s, and 80% of the analysed regions achieving moderate or strong correlations between the predicted and in vivo velocities. CFD predicted pressures were generally well matched to the Doppler-wire measurements, with some deviation in peak systolic values. Overall, this study presents a validated comprehensive workflow with extensive data for CFD simulation of TBAD
An Investigation of Polymeric Nanocomposite: Surface Functionalization and Nanofiller Effect
No full textProcessing and Characterization of Zinc Oxide Nanoparticle Filled Polymeric Nanocomposites
No full textInvestigation of the Interaction Between Magnetosheath Reconnection and Magnetopause Reconnection Driven by Oblique Interplanetary Tangential Discontinuity Using Three-Dimensional Global Hybrid Simulation
No full textMagnetosheath reconnection due to the interaction of an interplanetary directional discontinuity with the bow shock and Earth's magnetosphere under an initially northward interplanetary magnetic field (IMF) has been investigated in previous simulations (e.g., Guo et al., 2018, https://doi.org/10.1029/2018ja025679). Under an initially southward IMF, the magnetosheath reconnection could interact with reconnection at the magnetopause. In this study, using three-dimensional (3D) globalscale hybrid simulations, we present cases with incoming tangential discontinuities (TDs) in an initially southward IMF, which possess various magnetic field rotation angles (Delta Phi) and half-width (w), to study the effects of pre-existing magnetopause reconnection on the formation of magnetosheath flux ropes, as well as the subsequent interaction between the magnetopause reconnection and magnetosheath reconnection, with downstreams of both Quasi-perpendicular (Q-perpendicular to) and Quasi-parallel (Q-II) shock examined. The initial IMF is assumed to be oblique, with a finite B-x and B-z similar to that in Guo et al. (2018), https://dot org/10.1029/2018ja025679 but with a southward B-z < 0. Compared with the cases with an initially northward IMF, magnetopause reconnection weakens the compression processes of the TD and leads to less frequent reconnection in the magnetosheath. The existence and the structure of magnetosheath reconnection are found to strongly depend on the parameters w and Delta Phi of the TD. When interacting with the magnetopause reconnection, the magnetosheath flux ropes can re-reconnect with the geomagnetic dipole field lines, forming new structures of magnetopause flux ropes. The resulting evolution of flux rope configuration is illustrated.PublishedYe
Analysis of Chaetoconvosins a and B Using Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry
No full textTwo novel cytochalasins, chaetoconvosins A and B, isolated from Chaetomium convolutum were investigated using electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) in positive-ion mode. The main product ions in the high mass range for chaetoconvosins A and B are formed with the loss of H (2) O, CO, or both. The neutral loss of CH (3) NCO can be detected for chaetoconvosin B. However, their fragmentation patterns producing product ions in the low mass range vary greatly. It was found that hydroxyl or H atom linked to C1 is the key leading to the fragmentation differences. McLafferty-type rearrangement (producing the characteristic product ion at m/z 155), four-centered H rearrangement (generating m/z 193), and RDA reaction (producing m/z 203) are directly or indirectly related to the groups linked to C1. The identity of major product ions was supported by a D-labeling experiment
Micelles of Coil-Comb Block Copolymers in Selective Solvents: Competition of Length Scales
No full textWe study micelles formed by the coil-comb block copolymer, A-b-(A-g-B), in a B-selective solvent, S. The equilibrium distribution of micelles is obtained according to the thermodynamics of noninteracting micellar solutions, with the free energy of a single isolated micelle calculated using the self-consistent-field theory. Depending on the lengths of the various blocks and the balance of interactions, two types of micelles of different sizes and structures call be observed. This is a manifestation of the competition between two micellar assemblies of the coil-comb block copolymer at different length scales.DFG [1674/4]; National Natural Science Foundation of China [20620120105
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
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