Rheological Evaluation of Softened Binders Blended with Aged Asphalt Selected with a High-Temperature Mixing Chart

Reclaimed asphalt pavements (RAP) provide economic and environmental benefits. In recent decades, their use has increased, but rheological properties are affected by RAP aging, increasing stiffness, cracking, and susceptibility to water. To counteract these effects, rejuvenating agents are used, but they must be properly dosed to design quality mixtures. Therefore, different binders were analyzed, including virgin binder (VBB), binder modified by SBS polymer (MB), AC-RAP, binder softened using a rejuvenating agent, and binders softened with doses (15%, 30%, and 45%) of AC-RAP. The rheological properties were evaluated by dynamic shear rheometry (DSR) and beam-bending rheometry (BBR) tests, while the linear amplitude sweep (LAS) test was used to measure fatigue cracking and the multiple stress creep recovery (MSCR) test was used to measure rutting. A mixing chart was constructed based on a high temperature AC-RAP to satisfy the performance grade (PG 76-22). The results showed that softened binders become flexible, but when AC-RAP is added, they turn stiff and behave better than MB. Moreover, combining a rejuvenating agent and AC-RAP reduces the aging stiffness of RAP, improving its rheological properties without compromising the rutting or cracking resistance.     

Increased Heparanase Levels in Urine during Acute Puumala Orthohantavirus Infection Are Associated with Disease Severity

Old–world orthohantaviruses cause hemorrhagic fever with renal syndrome (HFRS), characterized by acute kidney injury (AKI) with transient proteinuria. It seems plausible that proteinuria during acute HFRS is mediated by the disruption of the glomerular filtration barrier (GFB) due to vascular leakage, a hallmark of orthohantavirus–caused diseases. However, direct infection of endothelial cells by orthohantaviruses does not result in increased endothelial permeability, and alternative explanations for vascular leakage and diminished GFB function are necessary. Vascular integrity is partly dependent on an intact endothelial glycocalyx, which is susceptible to cleavage by heparanase (HPSE). To understand the role of glycocalyx degradation in HFRS–associated proteinuria, we investigated the levels of HPSE in urine and plasma during acute, convalescent and recovery stages of HFRS caused by Puumala orthohantavirus. HPSE levels in urine during acute HFRS were significantly increased and strongly associated with the severity of AKI and other markers of disease severity. Furthermore, increased expression of HPSE was detected in vitro in orthohantavirus–infected podocytes, which line the outer surfaces of glomerular capillaries. Taken together, these findings suggest the local activation of HPSE in the kidneys of orthohantavirus–infected patients with the potential to disrupt the endothelial glycocalyx, leading to increased protein leakage through the GFB, resulting in high amounts of proteinuria.     

The second sodium pump: from the function to the gene

Transepithelial Na⁺ transport is mediated by passive Na⁺ entry across the luminal membrane and exit through the basolateral membrane by two active mechanisms: the Na⁺/K⁺ pump and the second sodium pump. These processes are associated with the ouabain-sensitive Na⁺/K⁺-ATPase and the ouabain-insensitive, furosemide-inhibitable Na⁺-ATPase, respectively. Over the last 40?years, the second sodium pump has not been successfully associated with any particular membrane protein. Recently, however, purification and cloning of intestinal α-subunit of the Na⁺-ATPase from guinea pig allowed us to define it as a unique biochemical and molecular entity. The Na⁺- and Na⁺/K⁺-ATPase genes are at the same locus, atp1a1, but have independent promoters and some different exons. Herein, we spotlight the functional characteristics of the second sodium pump, and the associated Na⁺-ATPase, in the context of its role in transepithelial transport and its response to a variety of physiological and pathophysiological conditions. Identification of the Na⁺-ATPase gene (atna) allowed us, using a bioinformatics approach, to explore the tertiary structure of the protein in relation to other P-type ATPases and to predict regulatory sites in the promoter region. Potential regulatory sites linked to inflammation and cellular stress were identified in the atna gene. In addition, a human atna ortholog was recognized. Finally, experimental data obtained using spontaneously hypertensive rats suggest that the Na⁺-ATPase could play a role in the pathogenesis of essential hypertension. Thus, the participation of the second sodium pump in transepithelial Na⁺ transport and cellular Na⁺ homeostasis leads us to reconsider its role in health and disease.     

Espondiloartritis en la infancia

Juvenile-onset spondyloarthritis is a special group within the entities included in the concept of spondyloarthritis, and is characterized by a predominantly peripheral involvement (arthritis and enthesitis), and more frequent presentation as undifferentiated forms. However, like its adult-onset equivalent, it has the potential to develop structural damage and progress to juvenile ankylosing spondylitis, with consequent irreversible functional impairment. Many important advances have been made in the understanding of the genetics and pathophysiology of juvenile-onset spondyloarthritis, as well as in the diagnosis and treatment of this entity. These advances are summarized in this article.