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In the last few years, a controversy has been raised regarding the nature of the chemical bonding present in phase change materials (PCMs), many of which are minerals such as galena (PbS), clausthalite (PbSe), and altaite (PbTe). Two opposite bonding models have claimed to be able to explain the extraordinary properties of PCMs in the last decade: the hypervalent (electron-rich multicenter) bonding model and the metavalent (electron-deficient) bonding model. In this context, a third bonding model, the electron-deficient multicenter bonding model, has been recently added. In this work, we comment on the pros and cons of the hypervalent and metavalent bonding models and briefly review the three approaches. We suggest that both hypervalent and metavalent bonding models can be reconciled with the third way, which considers that PCMs are governed by electron-deficient multicenter bonds. To help supporters of the metavalent and hypervalent bonding model to change their minds, we have commented on the chemical bonding in GeSe and SnSe under pressure and in several polyiodides with different sizes and geometries. [ABSTRACT FROM AUTHOR]

The Thermodynamic Difference Rules are capable of assessing the quality of a given set of thermodynamic data. This fact, and their inherent simplicity, makes them suitable for application by non-specialists. They are here applied to test existing literature values for the enthalpy of formation of the crystalline “hydrates” which are derived from the oxides of As(V) and P(V). The Δ f H ° data for the arsenic compounds are immediately validated. However, in the case of the phosphorus data, we conclude that the use of ½Δ f H °(P 4 O 10 ,s) to provide the parent oxide data is inappropriate. A value of Δ f H ° for P 2 O 5 , of −1607 ± 12 kJ mol −1 is now proposed. This is consistent with other recent estimations of Δ f H °(P 2 O 5 ,s). Similarly, values are proposed for Δ f G °(P 2 O 5 ,s)/kJ mol −1 ≈ −1514 ± 18 and S 298 °(P 2 O 5 ,s)/J mol −1 K −1 ≈ 110. Additionally, in cases where several values for a given thermodynamic property of the As(V) and P(V) oxide hydrates appear in the literature, these measurements are appraised in the context of the Difference Rules; in cases where no data are listed, values are now capable of being estimated. [ABSTRACT FROM AUTHOR]

• Liver transplant recipients presented the highest incidence of Clostridioides difficile infection. • Previous hospitalization and the use of quinolones are related with Clostridioides difficile infection. • Kidney failure, amoxicillin-clavulanate, and severity may be associated with recurrent Clostridioides difficile infection. There is limited knowledge about risk factors for Clostridioides difficile infection (CDI) and recurrent CDI in solid organ transplant (SOT) recipients. A case-control study of CDI in SOT recipients compared with controls (SOT recipients who did not present CDI). Sixty-seven patients from 1089 SOT recipients (6.2%) suffered at least one episode of CDI. The mean age was 55 ± 12 years and 20 cases (69%) were men. The accumulated incidence was 8% in liver transplantation, 6.2% in lung transplantation, 5.4% in heart transplantation, and 4.7% in kidney transplantation. Twenty-nine cases (43.3%) were diagnosed during the first 3 months after SOT. Forty-one cases (61.2%) were hospital acquired. Thirty-one patients with CDI presented with mild-moderate infection (46.3%), 30 patients with severe infection (44.8%), and 6 patients with severe-complicated disease (9%). Independent variables found to be related with CDI were hospitalization in the previous 3 months (odds ratio: 2.99; [95% confidence interval 1.21-7.37]) and the use of quinolones in the previous month (odds ratio: 3.71 [95% confidence interval 1.16-11.8]). Eleven patients (16.4%) had at least one recurrence of CDI. Previous treatment with amoxicillin-clavulanate, severe-complicated index episode, and high serum creatinine were associated with recurrent CDI in the univariant analysis Liver transplant recipients presented the highest incidence of CDI among SOT recipients. Risk factors for CDI were hospitalization in the previous 3 months and the use of quinolones in the previous month. [ABSTRACT FROM AUTHOR]