Pressure-induced transformations in LiCl–H2O at 77 K

A systematic study of the properties of high-density amorphous ice (HDA) in the presence of increasing amounts of salt is missing, especially because it is challenging to avoid ice crystallization upon cooling the pressurized liquid. In order to be able to study HDA also in the presence of small amounts of salt, we have investigated the transformation behaviour of quenched aqueous LiCl solutions (mole fraction x 1 GPa. The observed densification is consistent with the idea that a freeze concentrated LiCl solution of x = 0.14 (R = 6) segregates, which transforms to the glassy state upon cooling, and that the densification is only due to the Ih → HDA transition. Also the XRD patterns and DSC scans are almost unaffected by the presence of the segregated glassy LiCl solution. Upon heating at ambient pressure HDA experiences the polyamorphic transition to low-density amorphous ice (LDA) at ∼120 K, even at x ∼ 0.10. Based on the latent heat evolved in the transition we suggest that almost all water in the sample transforms to an LDA-like state, even the water in the vicinity of the ions. The glassy LiCl solution acts as a spectator that does not shift the transformation temperature significantly and experiences a glass-to-liquid transition at ∼140 K prior to the crystallization to cubic ice. By contrast, at x > 0.12 the phenomenology completely changes and is now dominated by the salt. Hexagonal ice no longer forms upon quenching the LiCl solution, but instead LDA forms. A broad pressure-induced transformation at >0.6 GPa can be attributed to the densification of LDA, the glassy LiCl solution and/or glassy hydrates.Fil: Ruiz, G. N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Innsbruck; AustriaFil: Bove, L. E.. Universite Pierre et Marie Curie; Francia. Ecole Polytechnique Federale de Lausanne; SuizaFil: Corti, Horacio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Loerting, T.. Universidad de Innsbruck; Austri

Endotracheal intubation to reduce aspiration events in acutely comatose patients: a systematic review

Background: It is customary to believe that a patient with a Glasgow Coma Scale (GCS) score less than or equal to 8 should be intubated to avoid aspiration. We conducted a systematic review to establish if patients with GCS 64 8 for trauma or non-traumatic emergencies and treated in the acute care setting (e.g., Emergency Department or Pre-hospital environment) should be intubated to avoid aspiration or aspiration pneumonia/pneumonitis, and consequently, reduce mortality. Methods: We searched six databases, Pubmed, Embase, Scopus, SpringerLink, Cochrane Library, and Ovid Emcare, from April 15th to October 14th, 2020, for studies involving low GCS score patients of whom the risk of aspiration and related complications was assessed. Results: Thirteen studies were included in the final analysis (7 on non-traumatic population, 4 on trauma population, 1 pediatric and 1 adult mixed case studies). For the non-traumatic cases, two prospective studies and one retrospective study found no difference in aspiration risk between intubated and non-intubated patients. Two retrospective studies reported a reduction in the risk of aspiration in the intubated patient group. For traumatic cases, the study that considered the risk of aspiration did not show any differences between the two groups. A study on adult mixed cases found no difference in the incidence of aspiration among intubated and non-intubated patients. A study on pediatric patients found increased mortality for intubated versus non-intubated non-traumatic patients with a low GCS score. Conclusion: Whether intubation results in a reduction in the incidence of aspiration events and whether these are more frequent in patients with low GCS scores are not yet established. The paucity of evidence on this topic makes clinical trials justifiable and necessary. Trial registration: Prospero registration number: CRD42020136987

Electrical Impedance Tomography and Prone Position During Ventilation in COVID-19 Pneumonia: Case Reports and a Brief Literature Review

At the end of 2019, a novel coronavirus (COVID-19) was identified as the cause of a cluster of pneumonia cases, with high needs of mechanical ventilation in critically ill patients. It is still unclear whether different types of COVID-19 pneumonia require different ventilator strategies. With electrical impedance tomography (EIT) we evaluated, in real time and bedside, the distribution of ventilation in the different pulmonary regions before, during, and after pronation in COVID-19 respiratory failure. We present a brief literature review of EIT in non-COVID-19 patients and a report of 2 COVID-19 patients: one that did not respond well and another one that improved during and after pronation. EIT might be a useful tool to decide whether prone positioning should or should not be used in COVID-19 pneumonia

Termination Casts: A Flexible Approach to Termination with General Recursion

This paper proposes a type-and-effect system called Teqt, which distinguishes terminating terms and total functions from possibly diverging terms and partial functions, for a lambda calculus with general recursion and equality types. The central idea is to include a primitive type-form "Terminates t", expressing that term t is terminating; and then allow terms t to be coerced from possibly diverging to total, using a proof of Terminates t. We call such coercions termination casts, and show how to implement terminating recursion using them. For the meta-theory of the system, we describe a translation from Teqt to a logical theory of termination for general recursive, simply typed functions. Every typing judgment of Teqt is translated to a theorem expressing the appropriate termination property of the computational part of the Teqt term.Comment: In Proceedings PAR 2010, arXiv:1012.455