Isocyanurate transformation induced healing of isocyanurate–oxazolidone polymers

Isocyanurate–oxazolidone (ISOX) polymers have been reported as a novel, intrinsically self‐healable thermoset, and their healing mechanism under the effect of nucleophiles, such as tertiary amines and pyridines during polymerization, is thoroughly investigated in this study. This work provides evidence that the healing behavior of the polymers results part from the transformation of isocyanurate to oxazolidone on the fracture surfaces of the ISOX polymers at elevated temperatures. The isocyanurate transformation is characterized by chemical composition of the ISOX polymers before and after a predetermined healing procedure, through a combination characterization of Fourier transform infrared spectroscopy and carbon nuclear magnetic resonance spectroscopy. From the chemical composition of the ISOX polymers, an increased oxazolidone fraction is observed after the healing event, which verifies the hypothesized healing mechanism. By correlating the change in oxazolidone fraction in the polymers during the healing event, with the corresponding healing performance of the polymers, healing efficiencies of the polymers are shown to be inversely proportional to the ratio of oxazolidone to isocyanurate in the polymers. The transformation to oxazolidone is also shown to be dependent on two variables, nucleophilicity of the polymerization catalyst and duration of the postcure. The isocyanate and epoxide polymerization mechanism in the presence of nucleophiles is also investigated to explain the effect of the catalyst nucleophilicity on the chemical composition as well as the healing performance of the ISOX polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48698.Isocyanurate‐to‐oxazolidone transformation within the polymers for healing.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154270/1/app48695-sup-0001-FigureS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154270/2/app48698_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154270/3/app48698.pd

Molybdenum sputtering film characterization for high gradient accelerating structures

Technological advancements are strongly required to fulfill the demands of new accelerator devices with the highest accelerating gradients and operation reliability for the future colliders. To this purpose an extensive R&D regarding molybdenum coatings on copper is in progress. In this contribution we describe chemical composition, deposition quality and resistivity properties of different molybdenum coatings obtained via sputtering. The deposited films are thick metallic disorder layers with different resistivity values above and below the molibdenum dioxide reference value. Chemical and electrical properties of these sputtered coatings have been characterized by Rutherford backscattering, XANES and photoemission spectroscopy. We will also present a three cells standing wave section coated by a molybdenum layer $\sim$ 500 nm thick designed to improve the performance of X-Band accelerating systems.Comment: manuscript has been submitted and accepted by Chinese Physics C (2012

Supernova type Ia luminosities, their dependence on second parameters, and the value of H_0

A sample of 35 SNe Ia with good to excellent photometry in B and V, minimum internal absorption, and 1200 < v < \approx 30000 km/s is compiled from the literature. As far as their spectra are known they are all Branch-normal. For 29 of the SNe Ia also peak magnitudes in I are known. The SNe Ia have uniform colors at maximum, i.e. =-0.012 mag (sigma=0.051) and =-0.276 mag (sigma=0.078). In the Hubble diagram they define a Hubble line with a scatter of $\sigma_M$=0.21-0.16 mag, decreasing with wavelength. The scatter is further reduced if the SNe Ia are corrected for differences in decline rate Delta_m_15 or color (B-V). A combined correction reduces the scatter to sigma<=0.13 mag. After the correction no significant dependence remains on Hubble type or galactocentric distance. The Hubble line suggests some curvature which can be differently interpreted. A consistent solution is obtained for a cosmological model with Omega_M=0.3, Omega_Lambda=0.7, which is indicated also by much more distant SNe Ia. Absolute magnitudes are available for eight equally blue (Branch-normal) SNe Ia in spirals, whose Cepheid distances are known. If their well defined mean values of M_B, M_V, and M_I are used to fit the Hubble line to the above sample of SNe Ia one obtains H_0=58.3 km/s/Mpc, or, after adjusting all SNe Ia to the average values of Delta_m_15 and (B-V), H_0=60.9 km/s/Mpc. Various systematic errors are discussed whose elimination tends to decrease H_0. The finally adopted value at the 90-percent level, including random and systematic errors, is H_0=58.5 +/- 6.3 km/s/Mpc. Several higher values of H_0 from SNe Ia, as suggested in the literature, are found to depend on large corrections for variations of the light curve parameter and/or on an unwarranted reduction of the Cepheid distances of the calibrating SNe Ia.Comment: 42 pages, including 9 figures; submitted to Ap

Environmental monitoring programme in the cell therapy facility of a research centre: preliminary investigation

Introduction. Recent discoveries in cell therapy research present new opportunities for cellular products to be used to treat severe, and as yet incurable, diseases. It is therefore essential to implement a quality control programme in order to ensure that safe cells and tissues are provided. Methods. In a preliminary phase of the setting up of a the cell factory, monitoring was carried out monthly over a 6-month period in one out of three cell therapy laboratories and filter rooms in order to evaluate the microbial contamination of air and surfaces and the presence of airborne particulates. Results. The mean total bacterial and fungal loads measured in the air in the centre of the filter room were 20.7 ± 28.9 colonyforming units (cfu)/m3 and 9.2 ± 15.4 cfu/m3, respectively, and 5.2 ± 4.1 cfu/m3 and 6.8 ± 13.4 cfu/m3, respectively, in the laboratory. The mean fungal load values recorded on the surfaces sampled in the laboratory were in 6 out of 18 cases higher than the reference values (5 cfu/plate). As to the results of particulate monitoring, with regard to the 0.5 ?m particles, about 83% of the samples revealed values below the limit of 350.000 particles per cubic metre. Conclusions. In this set-up phase, monitoring was able to pick out structural and organisational flaws acceptable in a laboratory compliant with Good Manufacturing Practices class C (Annex 1), but not in a class B facility. Thanks to this preliminary monitoring phase, and by correcting these flaws, the clean room facility could achieve compliance to class B

Dynamic contrast-enhanced magnetic resonance imaging of the wrist in early arthritis

Objectives: MRI has been proposed as the imaging method of choice to evaluate the long-term outcome in patients with early arthritis. The role of dynamic MRI, performed at presentation, in predicting the outcome of patients with early arthritis has been addressed in the present study. Methods: 39 patients with early arthritis, involving at least one wrist, were studied with clinical visits and laboratory investigations, every 3 months. Dynamic MRI was performed with a low-field (0.2T), extremity-dedicated machine (Artoscan, Esaote, Genova, Italy) equipped with a permanent magnet and with a dedicated hand and wrist coil. During the intravenous injection of Gd-DTPA, twenty consecutive fast images of 3 slices of the wrist were acquired. The synovial contrast enhancement ratio was calculated both as rate of early enhancement (REE) per second during the first 55" and as relative enhancement (RE) at t seconds. Results: In our cohort of patients, REE and RE were significantly lower than those observed in a historical cohort of 36 patients with active rheumatoid arthritis. In univariate analysis, low RE predicted complete remission of arthritis. In multivariate analysis, fulfillment of RA criteria during follow-up was predicted by high RE. The need for immunosuppressive treatment at the end of follow-up was predicted by both low RE and high REE. Conclusions: Dynamic MRI may be used to predict several outcomes of early arthritis involving the wris

The UTfit Collaboration Average of D meson mixing data: Spring 2012

We derive constraints on the parameters $M_{12}$, $\Gamma_{12}$ and $\Phi_{12}$ that describe $D$ meson mixing using all available data, allowing for CP violation. We also provide posterior distributions and predictions for observable parameters appearing in $D$ physics.Comment: 5 pages, 3 figure

Genetic Variants of the Renin-Angiotensin-Aldosterone System and Reverse Remodeling After Cardiac Resynchronization Therapy

Background: Reverse remodeling (RR) after cardiac resynchronization therapy (CRT) is associated with favorable clinical outcomes in heart failure (HF). The renin-angiotensin-aldosterone system (RAAS) is involved in the remodeling process. Methods and Results: We assessed the association between RR and 8 common RAAS gene variants, which were determined by TaqMan assays, in 156 outpatients with chronic HF. RR was defined as a O15% decrease in left ventricular end systolic volume (LVESV) at 9 (interquartile range 7e12) months after CRT. We matched 76 patients who did not show RR (RR) to 80 RR? control subjects by age, sex, HF etiology, New York Heart Association (NYHA) functional class and left ventricular ejection fraction (LVEF). The frequency of the minor allele of the NR3C2 gene (rs5522 C/T), encoding the mineralocorticoid receptor, was higher in RR than in RR (24/126 vs 10/150; P value after false discovery rate correction: <.0193). Conversely, LVESV decreased significantly less after CRT in carriers of the NR3C2 minor C allele (P 5 .02). After adjustment for age, sex, NYHA functional class, previous myocardial infarction, atrial fibrillation, and LVEF, RR remained independently associated with NR3C2 C allele carriage (odds ratio 3.093, 95% confidence interval 1.253e7.632). Conclusions: The association of RR after CRT with a common polymorphism in the mineralocorticoid receptor gene involved in aldosterone signaling suggests a possible role for variants in RAAS genes in progressive LV function decline, despite apparently effective CRT