National University of General San Martín

End-inspiratory pause (EIP) is traditionally discouraged in mechanically ventilated patients with chronic obstructive pulmonary disease (COPD) because it shortens expiratory time (TE) and may worsen hyperinflation. Previous data in hypoxemic patients suggest that, at equal total inspiratory time (TI), shorter insufflations followed by EIP can improve CO₂ elimination. Whether this strategy is effective and safe in obstructive lung disease remains unknown. To evaluate whether a ventilation with high inspiratory flow and EIP reduces arterial carbon dioxide (PaCO₂) without increasing hyperinflation in mechanically ventilated patients with COPD undergoing controlled hypoventilation. Prospective, single-center, randomized, cross-over physiological study including sedated, intubated adult patients with acute exacerbation of COPD, PaCO₂ ≥45 mmHg, and no spontaneous respiratory effort. Patients were randomized to two 30-minute ventilation strategies in volume-controlled mode: conventional ventilation without EIP (VentNO−PAUSE) and ventilation with EIP (VentPAUSE), in which inspiratory flow was increased and 40–50% of TI was replaced by an EIP. Total TI and TE were identical in both strategies. Arterial blood gases, respiratory mechanics, and hemodynamics were recorded. VentPAUSE significantly reduced PaCO₂ (58.5 ± 9.4 to 52.6 ± 10.4 mmHg; P < 0.001) and increased arterial pH (7.31 ± 0.09 to 7.34 ± 0.08; P < 0.001). Ventilatory ratio decreased (P < 0.001), indicating improved ventilatory efficiency. Oxygenation improved (PaO₂ and PaO₂/FiO₂; P < 0.05), while the alveolar–to–arterial oxygen difference was unchanged (p = 0.813). Total PEEP and auto-PEEP were not affected (P > 0.999). PaCO₂ reduction was greater in patients with higher respiratory system elastance. In sedated, mechanically ventilated patients with COPD, a strategy using high inspiratory flow with a short inspiratory pause reduces PaCO₂ and improves oxygenation without increasing auto-PEEP.

Brucella infection is frequently acquired by inhalation, but the pathogen disseminates systemically from the lungs. However, little is known about the interaction of Brucella spp. with the airways. Using a 3D air-exposed organotypic human bronchial tissue model (polarized 16HBE14o- bronchial epithelial cells grown over a collagen matrix containing MRC-5 lung fibroblasts), we analyzed Brucella abortus replication, translocation and cytokine responses over prolonged post-infection times. Apically inoculated B. abortus invaded, replicated and persisted during the whole follow-up (16 days) within the bronchial tissue without inducing cytotoxicity. Viable bacteria were also detected in the conditioned medium (CM) since day five post-infection, indicating release from the basolateral side. In parallel experiments, no invasion or bacterial release was detected for Escherichia coli. The levels of IL-6, IL-8 and MCP-1 were increased in CM from Brucella-infected 3D cultures and in monocultures of polarized bronchial epithelial cells or lung fibroblasts. Collagenase/gelatinase activity was increased in 3D cultures and MRC-5 monocultures. Infection transference from bronchial cells to lung fibroblasts was documented using monocultures. An immune cross-talk was detected, as cytokine levels were increased in fibroblasts stimulated with bronchial CM, and vice versa. These results suggest that the bronchial mucosa can sustain B. abortus persistence, replication and dissemination, and that it induces a proinflammatory response to which both epithelial cells and fibroblasts contribute.

La Localidad Arqueológica La María (Meseta Central de Santa Cruz, Argentina) cuenta con numerosos sitios con arte rupestre. Cerca de ellos hay potenciales fuentes de materias primas útiles para la producción de las pinturas. Al respecto, el objetivo del trabajo es contribuir al conocimiento de la base regional de recursos minerales, haciendo foco en los pigmentos. Realizamos un relevamiento de las fuentes identificadas en la localidad, describimos las características macroscópicas del material y evaluamos su utilidad como pigmento. Asimismo, realizamos sobre ellas, y sobre pigmentos recuperados de sitios arqueológicos, estudios composicionales mediante Espectroscopia infrarroja con transformada de Fourier, análisis dispersivo en energía asociado a microscopía electrónica de barrido y difracción de rayos X. Los resultados permiten obtener un panorama inicial de las características de las fuentes y los pigmentos disponibles, así como generar expectativas arqueológicas y discutir aspectos vinculados a su posible aprovisionamiento y uso, contemplando información experimental, etnohistórica y etnográfica.

In this work, we present the covalent functionalization of NiFe layered double hydroxides (LDHs) using tris(hydroxymethyl)aminomethane (TRIS) to enhance their stability, processability, and performance as catalysts for the oxygen evolution reaction (OER). LDHs are versatile materials with applications in energy storage, catalysis, and magnetism due to their tunable properties. TRIS molecules were covalently attached to NiFe-LDH using a modified hydrothermal method, confirmed through x-ray diffraction, infrared and Raman spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, elemental analysis, thermogravimetric analysis, and DFT+U calculations. The TRIS-functionalized NiFe-LDH showed predominant antiferromagnetic behavior with a blocking temperature of 7.5 K and a coercive field of 3900Oe at 2 K. This is attributed to enhanced structural order resulting from high synthesis temperatures enabled by TRIS, which prevent oxide formation at 180°C. Additionally, TRIS functionalization facilitates the creation of highly stable binder-free electrodes for OER in alkaline media via water-based ink formulation. The improved ink stability ensures better dispersion and deposition of the catalytic material, increasing surface area and electrocatalytic performance. While TRIS is removed during operation, its role in optimizing ink formulation and electrode integration makes NiFe-TRIS a robust and efficient catalyst for water splitting and electrochemical applications.

Abstract. In times of digital transformation, machines are expected to operate exclusively using the International System of Units (SI), something that humans have not yet fully achieved. The same should include sensor systems feeding data to those machines. This requires an internationally authoritative database for converting the non-SI units that humans enter to SI units at the level of the human–machine interface or human–sensor interface.