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The Transplant Centers belonging to Gruppo Italiano per il Trapianto di Midollo Osseo (GITMO) conducted a survey with the aim of evaluating the effect of SARS-CoV2 pandemic on the allogeneic transplant activity in Italy. The pandemic period from 1/3/2020 to 31/7/2020 was compared with the same period in 2019. Overall, in 2020 there was a 2.4% reduction in the number of allo-HCT cases compared to 2019. Interestingly, this deflection did not affect the acute leukemia cases (+5.7% in 2020). The use of peripheral blood-derived stem cells (+10.7%) and cryopreservation (97.4% of the centers) was highly adopted in 2020. Despite the sanitary emergency, almost all of the surveyed centers declared no impact of SARS-CoV2 pandemic on the transplant timing and outcomes, and the sanitary policy was positively evaluated by the majority of centers. The emergency measures ensured that only a minority of the allo-HCT patients had been infected by SARS-CoV2; however, a mortality of 42.1% among the allo-HCT patients hospitalized for COVID-19 was recorded. This survey gives us the information that the GITMO Group reacted positively to the pandemic. Thanks to the emergency strategies, the Italian allo-HCT activity continued safely, showing only a minor deflection and offering the same probability of cure to the transplanted patients.

Adipose stem cells (ASCs) are a crucial element in bone tissue engineering (BTE). They are easy to harvest and isolate, and they are available in significative quantities, thus offering a feasible and valid alternative to other sources of mesenchymal stem cells (MSCs), like bone marrow. Together with an advantageous proliferative and differentiative profile, they also offer a high paracrine activity through the secretion of several bioactive molecules (such as growth factors and miRNAs) via a sustained exosomal release which can exert efficient conditioning on the surrounding microenvironment. BTE relies on three key elements: (1) scaffold, (2) osteoprogenitor cells, and (3) bioactive factors. These elements have been thoroughly investigated over the years. The use of ASCs has offered significative new advancements in the efficacy of each of these elements. Notably, the phenotypic study of ASCs allowed discovering cell subpopulations, which have enhanced osteogenic and vasculogenic capacity. ASCs favored a better vascularization and integration of the scaffolds, while improvements in scaffolds’ materials and design tried to exploit the osteogenic features of ASCs, thus reducing the need for external bioactive factors. At the same time, ASCs proved to be an incredible source of bioactive, proosteogenic factors that are released through their abundant exosome secretion. ASC exosomes can exert significant paracrine effects in the surroundings, even in the absence of the primary cells. These paracrine signals recruit progenitor cells from the host tissues and enhance regeneration. In this review, we will focus on the recent discoveries which have involved the use of ASCs in BTE. In particular, we are going to analyze the different ASCs’ subpopulations, the interaction between ASCs and scaffolds, and the bioactive factors which are secreted by ASCs or can induce their osteogenic commitment. All these advancements are ultimately intended for a faster translational and clinical application of BTE.

A kinetic model is developed for the heterogeneous free-radical copolymerization of vinylidene fluoride and hexafluoropropylene in supercritical CO 2. The model accounts for polymerization in both the dispersed (polymer-rich) phase and in the continuous (polymer-free) supercritical phase, for radical interphase transport, diffusion limitations, and chain-length-dependent termination in the polymer-rich phase. A parameter evaluation strategy is developed and detailed to estimate most of the kinetic parameters a priori while minimizing their evaluation by direct fitting. The resulting model predictions compare favorably with the experimental results of conversion and MWD at varying monomer feed composition, monomer concentration, interphase area, and pressure of the system. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

background The use of aspirin for the prevention of thrombotic complications in polycythemia vera is controversial. methods We enrolled 518 patients with polycythemia vera, no clear indication for aspirin treatment, and no contraindication to such treatment in a double-blind, placebo-controlled, randomized trial to assess the safety and efficacy of prophylaxis with low-dose aspirin (100 mg daily). The two primary end points were the cumulative rate of nonfatal myocardial infarction, nonfatal stroke, or death from cardiovascular causes and the cumulative rate of nonfatal myocardial infarction, nonfatal stroke, pulmonary embolism, major venous thrombosis, or death from cardiovascular causes. The mean duration of follow-up was about three years. results Treatment with aspirin, as compared with placebo, reduced the risk of the combined end point of nonfatal myocardial infarction, nonfatal stroke, or death from cardiovascular causes (relative risk, 0.41; 95 percent confidence interval, 0.15 to 1.15; P=0.09) and the risk of the combined end point of nonfatal myocardial infarction, nonfatal stroke, pulmonary embolism, major venous thrombosis, or death from cardiovascular causes (relative risk, 0.40; 95 percent confidence interval, 0.18 to 0.91; P=0.03). Overall mortality and cardiovascular mortality were not reduced significantly. The incidence of major bleeding episodes was not significantly increased in the aspirin group (relative risk, 1.62; 95 percent confidence interval, 0.27 to 9.71). conclusions Low-dose aspirin can safely prevent thrombotic complications in patients with polycythemia vera who have no contraindications to such treatment.

A complex interplay between aggregation and coalescence occurs in many colloidal polymeric systems and determines the morphology of the final clusters of primary particles. To describe this process, a 2D population balance equation (PBE) based on cluster mass and fractal dimension is solved, employing a discretization method based on Gaussian basis functions. To prove the general reliability of the model and to show its potential, parametric simulations are performed employing both diffusion-limited-cluster aggregation (DLCA) and reaction-limited-cluster-aggregation (RLCA) kernels and different coalescence rates. It turns out that in both DLCA and RLCA regimes, a faster coalescence leads to smaller sized and more compact clusters, whereas a slow coalescence promotes the formation of highly reactive fractals, resulting in larger aggregates.

In recent years the use of supercritical carbon dioxide (scCO2) in polymer processing and polymerization reactions has merged as a “green” alternative to replace both organic solvents, environmentally hazardous (VOCs), and water, which use involves the production of large amount of waste streams. ScCO2 is non-toxic, inexpensive, and often exhibits high solubility in polymer matrixes. Moreover, it causes polymer plasticization, thus favoring the diffusion of low MW species (monomers, initiators or additives) in the polymer phase. In this work, the use of scCO2 as polymerization medium for two different special polymers is discussed. Fluorinated copolymers mainly find application in environmentally aggressive systems due to their high chemical and thermal resistance. In the case of vinylidene fluoride precipitation reaction in scCO2, bimodal MWDs are typically obtained. Different mechanisms have been proposed to explain such heterogeneity, such as chain-transfer to polymer and transport limitations of the radicals between supercritical and polymer phase. Here we show that carrying out the reaction in a stable dispersion, thus increasing the area between the two phases, monomodal MWDs are obtained, thus confirming the second proposed mechanism. Dendronized polymers are macromolecules which consist of a polymer backbone to which dendrons (tree like structures) of increasing size (generation) are attached at regular distances. The highly branched dendritic layer causes the denpol to change from a random coil polymer to a cylindrical nanoobject with set of features which make them unique macromolecules for a variety of applications. G3 macromonomers had already been synthesized and polymerized under conventional conditions (bulk and solution). Recently we carried out batch reactions in scCO2, using AIBN as initiator. Molar mass determinations with GPC show average molecular weights on the order of several millions, much higher then those obtained under conventional homogeneous conditions. The denpols obtained were checked by SFM for their structural integrity and mostly linear chains were observed. A series of trials with different conditions has been carried out in order to elucidate the reaction mechanism and to determine the role of scCO2

Radical emulsion polymerizations are a class of fast and exothermic reactions widely diffused around the world to produce a great variety of paints and plastics. At industrial scale, repeatability of emulsion polymerization processes within narrow limits is highly desirable; this means that final solids content, particles size, emulsion viscosity and polymer average molecular weight should vary little from batch to batch. Moreover, the process should be completed in the shortest possible time and preparing a latex at the highest possible concentration to save time in production. Because of all these critical features, a reliable modelling of such processes would be very helpful at industrial scale. In this work, a detailed model of emulsion polymerization, accounting for dosing strategies, temperature control modes, volume variations, radical diffusion (inside and outside the micelle/polymer particles) and different mechanisms of particles nucleation, is developed. A non-stationary numerical approach based onto the Smith-Ewart theory has been employed to compute the average number of radicals per particle. Finally, a series of experiments on the emulsion polymerization of vinyl acetate has been carried out in an indirectly cooled semibatch reactor (RC1, 1 L, Mettler Toledo) to validate the model.