Master curves for the sulphur assisted crosslinking reaction of natural rubber in the presence of nano- and nano-structured sp2 carbon allotropes

In this paper, master curves are reported for the crosslinking of a diene rubber with a sulphur based system in the presence of either nano- or nano-structured carbon allotropes, such as carbon nanotubes (CNT), a nanosized graphite with high surface area (HSAG) and carbon black (CB). Poly(1,4-cis-isoprene) from Hevea Brasiliensis was the diene rubber and crosslinking was performed in temperatures ranging from 151 to 180°C, with carbon allotropes below and above their percolation threshold. Such carbon allotropes were characterized by different aspect ratio, surface area and pH. However, in the crosslinking reaction, they revealed common behaviour. In fact, the specific interfacial area could be used to correlate crosslinking parameters, such as induction time (ts1) and activation energy (Ea) calculated by applying the autocatalytic model. Monotonous decrease of ts1 and increase of Ea were observed, with points lying on master curves, regardless of the nature of the carbon allotropes. Remarkable differences were however observed in the structure of the crosslinking network: when the carbon allotrope was above the percolation threshold much larger crosslinking density was obtained in the presence of CNT whereas composites based on HSAG became soluble in hydrocarbon solvent, after the reaction with a thiol. Proposed explanation of these results is based on the reactivity of carbon allotropes with sulphur and sulphur based compounds, demonstrated through the reaction of 1-dodecanethiol and sulphur with CNT and HSAG and with a model substrate such as anthracene

Synthesis of pyrrole derivatives of serinol for functionalization of carbon allotropes

N-Pyrrole-based heterocycles are present in many natural products,[1] medicinal agents,[2] and functional materials,[3,4] therefore substantial attention has been paid to develop efficient methods for pyrroles synthesis. Moreover, they are precursors for the synthesis of poly N-alkyl pyrroles which have wide ranging applications in electronics and sensors due to their tunable optoelectronic properties. We present here one operationally simple, practical and economical Paal-Knorr pyrrole condensation of serinol (2-amino-propan-1,3-diol, 1) with beta-dicarbonyl compounds 2 (and related acetal/ketals or enolesters), under neat conditions in the absence of any catalysts, which allows the synthesis of N-serinopyrrole derivatives (3) in good to excellent yield. Depending on substituents, compounds 3 show quite interesting amphiphilic polar/unpolar and variable -interaction properties. The mechanistic conclusion reached in the study, allowed to identify a direct method for the preparation of the precursor serinol-pyrrole from sugar derivatives. Typical examples of this reaction is the dehydrative condensation of galactaric acid (4) with serinol (1) (i.e. its serinol salt or other derivatives). Methods for the derivatization of carbon allotropes (CNT, Graphenes and Carbon Black) by the prepared pyrroles were investigated and the good dispersion properties of the resulting material proved

Serinol: a biosourced building block for better mechanical reinforcement and sustainable vulcanization of rubber compounds

Serinol and serinol derivatives were used to promote the mechanical reinforcement and the sulphur based crosslinking of rubber compounds. Reaction of serinol was performed with aldehydes and ketones, such as cinnamaldehyde, acetone, 2,5-hexanedione and camphor, obtaining the regiospecific synthesis of either imines or oxazolidines. Paal-Knorr reaction was as well carried out between serinol and 2,5-hexanedione, obtaining a serinol derivative containing a pyrrole ring, 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3-propanediol, named as serinolpyrrole. All the reactions were performed in the absence of solvents and catalysts and were characterized by high and also quantitative yields. Thanks to the reactions’ specificity, pure substances were obtained, with controlled atoms hybridization. The aromatic pyrrole ring was exploited to form adducts of serinolpyrrole with carbon allotropes. Adducts of SP with carbon black promoted the reduction of filler networking in silica based compounds. Serinol and immine as well oxazolidine derivatives were efficient secondary accelerators in silica based compounds and are thus suitable substances for the replacement of DPG. Tuning of vulcanization kinetics was performed

Internal Communications, Engagement and Trust in a Mission-Based Organization: Examining how the strength of the mission of an organization plays a role in engagement, trust in leadership and communication

This paper describes a SDN-based solution that, by leveraging and coordinating many functionalities that reside at both WDM and Ethernet layers, orchestrates network resources with the aim to maximize host-to-host data transfer rate

Treatment of Graft versus Host Disease with Mesenchymal Stromal Cells: A Phase I Study on 40 Adult and Pediatric Patients

Abstract This phase I multicenter study was aimed at assessing the feasibility and safety of intravenous administration of third party bone marrow–derived mesenchymal stromal cells (MSC) expanded in platelet lysate in 40 patients (15 children and 25 adults), experiencing steroid-resistant grade II to IV graft-versus-host disease (GVHD). Patients received a median of 3 MSC infusions after having failed conventional immunosuppressive therapy. A median cell dose of 1.5 × 10 6 /kg per infusion was administered. No acute toxicity was reported. Overall, 86 adverse events and serious adverse events were reported in the study, most of which (72.1%) were of infectious nature. Overall response rate, measured at 28 days after the last MSC injection, was 67.5%, with 27.5% complete response. The latter was significantly more frequent in patients exhibiting grade II GVHD as compared with higher grades (61.5% versus 11.1%, P = .002) and was borderline significant in children as compared with adults (46.7 versus 16.0%, P = .065). Overall survival at 1 and 2 years from the first MSC administration was 50.0% and 38.6%, with a median survival time of 1.1 years. In conclusion, MSC can be safely administered on top of conventional immunosuppression for steroid resistant GVHD treatment. Eudract Number 2008-007869-23, NCT01764100

Parathyroid Retrospective Analysis of Neoplasms Incidence (pTRANI Study): An Italian Multicenter Study on Parathyroid Carcinoma and Atypical Parathyroid Tumour

Background: Parathyroid cancer (PC) is a rare sporadic or hereditary malignancy whose histologic features were redefined with the 2022 WHO classification. A total of 24 Italian institutions designed this multicenter study to specify PC incidence, describe its clinical, functional, and imaging characteristics and improve its differentiation from the atypical parathyroid tumour (APT). Methods: All relevant information was collected about PC and APT patients treated between 2009 and 2021. Results: Among 8361 parathyroidectomies, 351 patients (mean age 59.0 ± 14.5; F = 210, 59.8%) were divided into the APT (n = 226, 2.8%) and PC group (n = 125, 1.5%). PC showed significantly higher rates (p < 0.05) of bone involvement, abdominal, and neurological symptoms than APT (48.8% vs. 35.0%, 17.6% vs. 7.1%, 13.6% vs. 5.3%, respectively). Ultrasound (US) diameter >3 cm (30.9% vs. 19.3%, p = 0.049) was significantly more common in the PC. A significantly higher frequency of local recurrences was observed in the PC (8.0% vs. 2.7%, p = 0.022). Mortality due to consequences of cancer or uncontrolled hyperparathyroidism was 3.3%. Conclusions: Symptomatic hyperparathyroidism, high PTH and albumin-corrected serum calcium values, and a US diameter >3 cm may be considered features differentiating PC from APT. 2022 WHO criteria did not impact the diagnosis

Clinical characteristics and risk factors associated with COVID-19 severity in patients with haematological malignancies in Italy: a retrospective, multicentre, cohort study

Several small studies on patients with COVID-19 and haematological malignancies are available showing a high mortality in this population. The Italian Hematology Alliance on COVID-19 aimed to collect data from adult patients with haematological malignancies who required hospitalisation for COVID-19

A Molecular Dynamics Study of Noncovalent Interactions between Rubber and Fullerenes

The percolation and networking of filler particles is an important issue in the field of rubber reinforcement, and much effort is given to clarify the true nature of the reinforcement mechanism and the viscoelastic behavior. The concentration of nanofillers also in the presence of large amounts of carbon black is a parameter that can influence the macroscopic rubber behavior. In this paper, noncovalent interactions between C60 fullerenes with poly-1,4-cis-isoprene (PI) either as such or modified are studied through atomistic simulations based on Molecular Mechanics (MM) and Molecular Dynamics (MD) methods. At first the conformational properties of a single chain and of twelve PI chains in a periodic simulation box are studied. Afterwards, the conformational properties of a single PI chain polymer terminated with a -COOH group, and then a bulk system formed by chains of unmodified and some PI modified chains are considered. Then, the systems formed by adding fullerenes to these two different bulk systems were studied. Relatively small interaction energy between rubber and fullerenes being well dispersed in the sample was found. The simulations showed a preferential tendency of fullerenes to display self-aggregation, in the presence of even a small fraction of modified polymer chains