Chemical recycling of polyethylene terephthalate (PET) to monomers: Mathematical modeling of the transesterification reaction of bis(2-hydroxyethyl) terephthalate to dimethyl terephthalate

The accumulation of plastic waste in the environment is making recycling a compelling issue, particularly for polyethylene terephthalate (PET), used in products with a short shelf-life. An appealing route to chemical recycling of PET is glycolysis, leading to bis(2-hydroxyethyl) terephthalate (BHET). Its subsequent transesterification with methanol to dimethyl terephthalate (DMT) is crucial for the recovery of polymer-grade monomers. To favor the industrial applicability of this process, this work investigates the influence of three main parameters, i.e. the methanol to ethylene glycol molar ratio, the solvent to oligomers molar ratio and the mass fraction of the catalyst, on the transesterification of BHET to DMT. A kinetic model has been proposed, and the reaction rates evaluated by comparison with the experimental data. The model was used to predict the performances of the process in a wide range of operating conditions, in order to establish the optimal ones for high yield to DMT

A computational framework for two-dimensional random walks with restarts

The treatment of two-dimensional random walks in the quarter plane leads to Markov processes which involve semi-infinite matrices having Toeplitz or block Toeplitz structure plus a low-rank correction. We propose an extension of the framework introduced in [D. A. Bini, S. Massei, and B. Meini, Math. Comp., 87 (2018), pp. 2811-2830] which allows us to deal with more general situations such as processes involving restart events. This is motivated by the need for modeling processes that can incur in unexpected failures like computer system reboots. We present a theoretical analysis of an enriched Banach algebra that, combined with appropriate algorithms, enables the numerical treatment of these problems. The results are applied to the solution of bidimensional quasi-birth-death processes with infinitely many phases which model random walks in the quarter plane, relying on the matrix analytic approach. The reliability of our approach is confirmed by extensive numerical experimentation on several case studies

SH-wave reflection seismic survey at the Patigno landslide: integration with a previously acquired P-wave seismic profile

Seismic investigation on landslide is hampered by several factors that could prevent the use of the reflection seismic method to characterize the subsurface architecture (Jongmans and Garambois, 2007). Moreover, acquisition and processing of reflection seismic data are more time consuming compared with other geophysical techniques such as refraction seismic and electrical resistivity tomography (ERT), leading inevitably to higher costs. Notwithstanding these difficulties, recently some attempts to delineate the deep slip surface of large landslides have been carried out using P-wave reflection seismic surveys (Apuani et al., 2012; Stucchi and Mazzotti, 2009; Stucchi et al., 2014;). P-wave reflection seismic method is effective in imaging the slip surface at a depth sufficiently greater than the seismic wavelength, whereas, for very shallow horizons, it suffers from the limited resolution that can be obtained by the use of compressional waves. In this regards, SH-waves can be used to overcome this limitation (Deidda and Balia, 2001; Guy, 2006; Pugin et al., 2006,), but they require a specifically-designed energy source for waves generation, geophones measuring horizontal components of particles motion and an accurate choice of acquisition parameters. On the contrary, due to attenuation, the depth of investigation for SHwaves can be lower than for P-waves (Pugin et al., 2006). Therefore the geological understanding of a mass movement can take advantage of a combined use of both these geophysical methodologies. This is the case of the Patigno landslide, a great landslide located in the upper basin of Magra River, in the Northern Appennines, Italy (Fig.1), where a P-wave study carried out in the last years (Stucchi et al., 2014) was able to image the deepest discontinuity of the landslide body at around 40-50 m depth, but no description of the shallower layers can be inferred. Because these surface layers are the slip surfaces of quick reactivation movements of the landslide, an SH high-resolution reflection seismic survey was planned along the previous P-wave profile (Fig.1). This new survey associated to the P-wave investigation allows a more robust description of the landslide body, from the deepest discontinuity up to the very shallow portions of the landslide. This work describes the planning, acquisition and processing of the SH reflection seismic survey, and also gives a possible combined interpretation of both P and SH seismic images

7th Workshop on Matrix Equations and Tensor Techniques

No abstract availabl

Long-term clinical outcomes in critical limb ischemia--A retrospective study of 181 patients

Critical limb ischemia (CLI) is the most severe manifestation of the peripheral arterial disease. To date, several prognostic factors have been identified but the data of long-term follow-up in real life setting are scarce. The aim of our study is to describe a large group of CLI patients and identify possible prognostic factors, in a long-term follow-up

PReS-FINAL-2232: Long-term follow-up in a national cohort of MKD patients: search for clinical predictors of a spontaneous improvement

No abstract availabl

Recognition in emergency department of septic patients at higher risk of death: Beware of patients without fever

Background and Objectives: Chances of surviving sepsis increase markedly upon prompt diagnosis and treatment. As most sepsis cases initially show-up in the Emergency Department (ED), early recognition of a septic patient has a pivotal role in sepsis management, despite the lack of precise guidelines. The aim of this study was to identify the most accurate predictors of in-hospital mortality outcome in septic patients admitted to the ED. Materials and Methods: We compared 651 patients admitted to ED for sepsis (cases) with 363 controls (non-septic patients). A Bayesian mean multivariate logistic regression model was performed in order to identify the most accurate predictors of in-hospital mortality outcomes in septic patients. Results: Septic shock and positive qSOFA were identified as risk factors for in-hospital mortality among septic patients admitted to the ED. Hyperthermia was a protective factor for in-hospital mortality. Conclusions: Physicians should bear in mind that fever is not a criterium for defining sepsis; according to our results, absence of fever upon presentation might be indicative of greater severity and diagnosis of sepsis should not be delayed

PSNCBAM-1 analogs: Structural evolutions and allosteric properties at cannabinoid CB1 receptor

Allosteric modulation of the CB1Rs could represent an alternative strategy for the treatment of diseases in which these receptors are involved, without the undesirable effects associated with their orthosteric stimulation. PSNCBAM-1 is a reference diaryl urea derivative that positively affects the binding affinity of orthosteric ligands (PAM) and negatively affects the functional activity of orthosteric ligands (NAM) at CB1Rs. In this work we reported the design, synthesis and biological evaluation of three different series of compounds, derived from structural modifications of PSNCBAM-1 and its analogs reported in the recent literature. Almost all the new compounds increased the percentage of binding affinity of CP55940 at CB1Rs, showing a PAM profile. When tested alone in the [35S]GTPγS functional assay, only a few derivatives lacked detectable activity, so were tested in the same functional assay in the presence of CP55940. Among these, compounds 11 and 18 proved to be functional NAMs at CB1Rs, dampening the orthosteric agonist-induced receptor functionality by approximately 30%. The structural features presented in this work provide new CB1R-allosteric modulators (with a profile similar to the reference compound PSNCBAM-1) and an extension of the structure-activity relationships for this type of molecule at CB1Rs

Anti-tumor activity of CpG-ODN aerosol in mouse lung metastases

Studies in preclinical models have demonstrated the superior anti-tumor effect of CpG oligodeoxynucleotides (CpG-ODN) when administered at the tumor site rather than systemically. We evaluated the effect of aerosolized CpG-ODN on lung metastases in mice injected with immunogenic N202.1A mammary carcinoma cells or weakly immunogenic B16 melanoma cells. Upon reaching the bronchoalveolar space, aerosolized CpG-ODN activated a local immune response, as indicated by production of IL-12p40, IFN-γ and IL-1β and by recruitment and maturation of DC cells in bronchoalveolar lavage fluid of mice. Treatment with aerosolized CpG-ODN induced an expansion of CD4+ cells in lung and was more efficacious than systemic i.p. administration against experimental lung metastases of immunogenic N202.1A mammary carcinoma cells, whereas only i.p. delivery of CpG-ODN provided anti-tumor activity, which correlated with NK cell expansion in the lung, against lung metastases of the poorly immunogenic B16 melanoma. The inefficacy of aerosol therapy to induce NK expansion was related to the presence of immunosuppressive macrophages in B16 tumor-bearing lungs, as mice depleted of these cells by clodronate treatment responded to aerosol CpG-ODN through expansion of the NK cell population and significantly reduced numbers of lung metastases. Our results indicate that tumor immunogenicity and the tumor-induced immunosuppressive environment are critical factors to the success of CpG therapy in the lung, and point to the value of routine sampling of the lung immune environment in defining an optimal immunotherapeutic strategy