The effect of copolymer concentration, temperature, and sodium halides (NaI, NaBr, NaCl, and NaF) on micellization and micellar properties of a poly(ethylene oxide)-
block-poly(propylene oxide)-
...block-poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic copolymer (Pluronic L64: EO
13PO
30EO
13), was examined by different methods such as dye spectral change, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), small angle neutron scattering (SANS), dynamic light scattering (DLS), viscosity, and cloud point (CP). Temperature/polymer concentration/salt dependent aggregation behavior of L64 was observed. The data on critical micelle concentration (CMC), critical micelle temperature (CMT), (CP), micelle size, and shape are reported. The Fourier transform infrared (FTIR) showed temperature dependent changes in C–O–C stretching variation band towards higher wave numbers and broadening of band width during the micellization process; this was attributed to increase in proportion of the anhydrous methyl groups, while the proportion of the hydrated methyl groups was decreased. Differential scanning calorimetry (DSC) provides CMTs and CPs from the same experiment. CMC values derived from dye spectral change, decrease significantly with the addition of salt. The increases in salt/copolymer concentration lower the onset temperature of micellization (CMT). Halide anions influence both CMT and CP in the order of F
− > Cl
− > Br
− > I
− when total salt and copolymer concentration kept constant. SANS results show the increase of inter-micellar interaction due to the increase in temperature/salt concentration; this is supported by viscosity data.
This study reports the feasibility to fabricate large size Ti-6Al-4V alloy parts using the retained powder after screened out the finer powder for additive manufacturing. Effects of powder size on ...the microstructure and mechanical properties of powder compacts were studied. Effects of HIPing cycle on relative density distribution of large size powder compact were also investigated. Hot compression tests of as-HIPed powder compact were conducted. Prediction of temperature field distribution of large size powder compact during ring rolling was obtained though finite element method (FEM). The results showed that the powder size has no obvious influence on the microstructure and mechanical properties of as-HIPed Ti-6Al-4V alloy. The homogeneous HIPed powder compact with large dimensions can be produced through an optimized HIPing schedule. The optimized hot working processing window from the isothermal compression tests is temperature at 940–970°C and strain rate at 1–10s−1. The hot workability of Ti-6Al-4V powder compact is comparable or better than that of as-cast alloys. On the basis of isothermal compression tests and FEM results, a large workpiece of Ti-6Al-4V powder component has been successfully formed by ring rolling, and the mechanical performance of ring-rolled powder compact have some improvements than that of as-HIPed alloys.
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•This work exploits a potential application for the retained Ti-6Al-4V powder after screening out the fine powder for AM.•Large size Ti-6Al-4V powder compacts can be successfully produced through optimizing HIPing cycle.•The hot workability of Ti-6Al-4V powder compact is comparable than that of as-cast alloys, or better.•The mechanical properties of Ti-6Al-4V powder compact have some improvements after ring rolling.
The cross section of the e+e−→Λc+Λ¯c− process is measured with unprecedented precision using data collected with the BESIII detector at /¯s=4574.5, 4580.0, 4590.0 and 4599.5 MeV. The nonzero cross ...section near the Λc+Λ¯c− production threshold is cleared. At center-of-mass energies /¯s=4574.5 and 4599.5 MeV, the higher statistics data enable us to measure the Λc polar angle distributions. From these, the Λc electric over magnetic form-factor ratios (|GE/GM|) are measured for the first time. They are found to be 1.14±0.14±0.07 and 1.23±0.05±0.03, respectively, where the first uncertainties are statistical and the second are systematic.
The process e+e- → Λ Λ ¯ is studied using data samples at √s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. The Born cross section is ...measured at √s=2.2324 GeV, which is 1.0 MeV above the Λ Λ ¯ mass threshold, to be 305±$45_{-36}^{+66}$ pb, where the first uncertainty is statistical and the second systematic. The substantial cross section near threshold is significantly larger than that expected from theory, which predicts the cross section to vanish at threshold. The Born cross sections at √s=2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with improved precision. Finally, the corresponding effective electromagnetic form factors of Λ are deduced.
Cross sections of the process e+e− → π0 π0 J / ψ at center-of-mass energies between 3.808 and 4.600 GeV are measured with high precision by using 12.4 fb−1 of data samples collected with the BESIII ...detector operating at the BEPCII collider facility. A fit to the measured energy-dependent cross sections confirms the existence of the charmoniumlike state Y ( 4220 ) . The mass and width of the Y ( 4220 ) are determined to be ( 4220.4 ± 2.4 ± 2.3 ) MeV / c2 and ( 46.2 ± 4.7 ± 2.1 ) MeV , respectively, where the first uncertainties are statistical and the second systematic. The mass and width are consistent with those measured in the process e+e− → π+π− J / ψ. The neutral charmonium-like state Zc ( 3900 )0 is observed prominently in the π 0 J / ψ invariant-mass spectrum, and, for the first time, an amplitude analysis is performed to study its properties. The spin-parity of Zc ( 3900 )0 is determined to be JP = 1+, and the pole position is ( 3893.1 ± 2.2 ± 3.0 ) − i ( 22.2 ± 2.6 ± 7.0 ) MeV / c2, which is consistent with previous studies of electrically charged Zc ( 3900 )±. In addition, cross sections of e+e− → π0Zc ( 3900 )0 → π0π0 J / ψ are extracted, and the corresponding line shape is found to agree with that of the Y ( 4220 ).
Purpose
To develop an approach for automated quantification of myocardial infarct heterogeneity in late gadolinium enhancement (LGE) cardiac MRI.
Methods
We acquired 2D short‐axis cine and 3D LGE in ...10 pigs with myocardial infarct. The 2D cine myocardium was segmented and registered to the LGE images. LGE image signal intensities within the warped cine myocardium masks were analyzed to determine the thresholds of infarct core (IC) and gray zone (GZ) for the standard‐deviation (SD) and full‐width‐at‐halfmaximum (FWHM) methods. The initial IC, GZ, and IC + GZ segmentations were postprocessed using a normalized cut approach. Cine segmentation and cine‐LGE registration accuracies were evaluated using dice similarity coefficient and average symmetric surface distance. Automated IC, GZ, and IC + GZ volumes were compared with manual results using Pearson correlation coefficient (r), Bland‐Altman analyses, and intraclass correlation coefficient.
Results
For n = 87 slices containing scar, we achieved cine segmentation dice similarity coefficient = 0.87 ± 0.12, average symmetric surface distance = 0.94 ± 0.74 mm (epicardium), and 1.03 ± 0.82 mm (endocardium) in the scar region. For cine‐LGE registration, dice similarity coefficient was 0.90 ± 0.06 and average symmetric surface distance was 0.72 ± 0.39 mm (epicardium) and 0.86 ± 0.53 mm (endocardium) in the scar region. For both SD and FWHM methods, automated IC, GZ, and IC + GZ volumes were strongly (r > 0.70) correlated with manual measurements, and the correlations were not significantly different from interobserver correlations (P > .05). The agreement between automated and manual scar volumes (intraclass correlation coefficient = 0.85‐0.96) was similar to that between two observers (intraclass correlation coefficient = 0.81‐0.99); automated scar segmentation errors were not significantly different from interobserver segmentation differences (P > .05).
Conclusions
Our approach provides fully automated cine‐LGE MRI registration and LGE myocardial infarct heterogeneity quantification in preclinical studies.
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