Explore the vast range of titles available.

Background Common respiratory illnesses, such as emphysema and chronic obstructive pulmonary disease, are characterized by connective tissue damage and remodeling. Two major fibers govern the mechanics of airway tissue: elastin enables stretch and permits airway recoil, while collagen prevents overextension with stiffer properties. Collagenase and elastase degradation treatments are common avenues for contrasting the role of collagen and elastin in healthy and diseased states; while previous lung studies of collagen and elastin have analyzed parenchymal strips in animal and human specimens, none have focused on the airways to date. Methods Specimens were extracted from the proximal and distal airways, namely the trachea, large bronchi, and small bronchi to facilitate evaluations of material heterogeneity, and subjected to biaxial planar loading in the circumferential and axial directions to assess airway anisotropy. Next, samples were subjected to collagenase and elastase enzymatic treatment and tensile tests were repeated. Airway tissue mechanical properties pre- and post-treatment were comprehensively characterized via measures of initial and ultimate moduli, strain transitions, maximum stress, hysteresis, energy loss, and viscoelasticity to gain insights regarding the specialized role of individual connective tissue fibers and network interactions. Results Enzymatic treatment demonstrated an increase in airway tissue compliance throughout loading and resulted in at least a 50% decrease in maximum stress overall. Strain transition values led to significant anisotropic manifestation post-treatment, where circumferential tissues transitioned at higher strains compared to axial counterparts. Hysteresis values and energy loss decreased after enzymatic treatment, where hysteresis reduced by almost half of the untreated value. Anisotropic ratios exhibited axially led stiffness at low strains which transitioned to circumferentially led stiffness when subjected to higher strains. Viscoelastic stress relaxation was found to be greater in the circumferential direction for bronchial airway regions compared to axial counterparts. Conclusion Targeted fiber treatment resulted in mechanical alterations across the loading range and interactions between elastin and collagen connective tissue networks was observed. Providing novel mechanical characterization of elastase and collagenase treated airways aids our understanding of individual and interconnected fiber roles, ultimately helping to establish a foundation for constructing constitutive models to represent various states and progressions of pulmonary disease.

Respiratory diseases represent a significant healthcare burden, as evidenced by the devastating impact of COVID-19. Biophysical models offer the possibility to anticipate system behavior and provide insights into physiological functions, advancements which are comparatively and notably nascent when it comes to pulmonary mechanics research. In this context, an Inverse Finite Element Analysis (IFEA) pipeline is developed to construct the first continuously ventilated three-dimensional structurally representative pulmonary model informed by both organ- and tissue-level breathing experiments from a cadaveric human lung. Here we construct a generalizable computational framework directly validated by pressure, volume, and strain measurements using a novel inflating apparatus interfaced with adapted, lung-specific, digital image correlation techniques. The parenchyma, pleura, and airways are represented with a poroelastic formulation to simulate pressure flows within the lung lobes, calibrating the model’s material properties with the global pressure-volume response and local tissue deformations strains. The optimization yielded the following shear moduli: parenchyma (2.8 kPa), airways (0.2 kPa), and pleura (1.7 Pa). The proposed complex multi-material model with multi-experimental inputs was successfully developed using human lung data, and reproduced the shape of the inflating pressure-volume curve and strain distribution values associated with pulmonary deformation. This advancement marks a significant step towards creating a generalizable human lung model for broad applications across animal models, such as porcine, mouse, and rat lungs to reproduce pathological states and improve performance investigations regarding medical therapeutics and intervention.

The Guaymas Basin spreading center, at 2000 m depth in the Gulf of California, is overlain by a thick sedimentary cover. Across the basin, localized temperature anomalies, with active methane venting and seep fauna exist in response to magma emplacement into sediments. These sites evolve over thousands of years as magma freezes into doleritic sills and the system cools. Although several cool sites resembling cold seeps have been characterized, the hydrothermally active stage of an off-axis site was lacking good examples. Here, we present a multidisciplinary characterization of Ringvent, an ~1 km wide circular mound where hydrothermal activity persists ~28 km northwest of the spreading center. Ringvent provides a new type of intermediate-stage hydrothermal system where off-axis hydrothermal activity has attenuated since its formation, but remains evident in thermal anomalies, hydrothermal biota coexisting with seep fauna, and porewater biogeochemical signatures indicative of hydrothermal circulation. Due to their broad potential distribution, small size and limited life span, such sites are hard to find and characterize, but they provide critical missing links to understand the complex evolution of hydrothermal systems.

The aquaculture of Argopecten purpuratus (Peruvian scallop) is a profitable activity with positive impacts on the local economy. However, the development of biofouling on the culture lantern nets generates negative environmental impacts that affect its sustainability. A feasible option aimed at reducing the development of biofouling is to increase the frequency of lantern nets exchange. In this study, we tested whether doubling the lantern net exchange frequency in the final phase of culture reduces biofouling and, in turn, improves the growth and survival of A. purpuratus. For this purpose, in the concession of a company dedicated to the cultivation of A. purpuratus in Samanco Bay, Peru, four 10‐floor lantern nets were placed at 25 organisms per floor, divided into two treatments (T1 and T2) with two replicates. One group of these (T1) was exchanged after 30 days, and another group (T2) was maintained until harvest. As a result of the lantern nets exchange, biofouling weight was reduced by 64.6%, survival improved by 10.8%, gonad weight increased by 52.5%, and adductor muscle weight increased by 62.4%, which represents an additional net income of 6582.58 US$ per ha. This study demonstrates the significant benefits of regular lantern net exchanges in mitigating biofouling and enhancing the overall yield and economic viability of A. purpuratus culture, contributing to the advancement of more sustainable aquaculture practices.

Francisella noatunensis subsp. orientalis (Fno) is the causative agent of piscine francisellosis in warm water fish including tilapia. The disease induces chronic granulomatous inflammation with high morbidity and can result in high mortality. Early and accurate detection of Fno is crucial to set appropriate outbreak control measures in tilapia farms. Laboratory detection of Fno mainly depends on bacterial culture and molecular techniques. Recombinase polymerase amplification (RPA) is a novel isothermal technology that has been widely used for the molecular diagnosis of various infectious diseases. In this study, a recombinase polymerase amplification (RPA) assay for rapid detection of Fno was developed and validated. The RPA reaction was performed at a constant temperature of 42°C for 20 min. The RPA assay was performed using a quantitative plasmid standard containing a unique Fno gene sequence. Validation of the assay was performed not only by using DNA from Fno, closely related Francisella species and other common bacterial pathogens in tilapia farms, but also by screening 78 Nile tilapia and 5 water samples. All results were compared with those obtained by previously established real-time qPCR. The developed RPA showed high specificity in detection of Fno with no cross-detection of either the closely related Francisella spp. or the other tested bacteria. The Fno-RPA performance was highly comparable to the published qPCR with detection limits at 15 and 11 DNA molecules detected, respectively. The RPA gave quicker results in approximately 6 min in contrast to the qPCR that needed about 90 min to reach the same detection limit, taking only 2.7-3 min to determine Fno in clinical samples. Moreover, RPA was more tolerant to reaction inhibitors than qPCR when tested with field samples. The fast reaction, simplicity, cost-effectiveness, sensitivity and specificity make the RPA an attractive diagnostic tool that will contribute to controlling the infection through prompt on-site detection of Fno.

Many affected counties have had experienced a shortage of personal protective equipment (PPE) during the coronavirus disease (COVID-19) pandemic. We aimed to investigate the needs of healthcare professionals and the technical difficulties faced by them during the initial outbreak. A cross-sectional web-based survey was conducted among the healthcare workforce in the most populous cities from three Latin American countries in April 2020. In total, 1,082 participants were included. Of these, 534 (49.4%), 263 (24.3%), and 114 (10.5%) were physicians, nurses, and other professionals, respectively. At least 70% of participants reported a lack of PPE. The most common shortages were shortages in gown coverall suits (643, 59.4%), N95 masks (600, 55.5%), and face shields (569, 52.6%). Professionals who performed procedures that generated aerosols reported shortages more frequently (p<0.05). Professionals working in the emergency department and primary care units reported more shortages than those working in intensive care units and hospital-based wards (p<0.001). Up to 556 (51.4%) participants reported the lack of sufficient knowledge about using PPE. Professionals working in public institutions felt less prepared, received less training, and had no protocols compared with their peers in working private institutions (p<0.001). Although the study sample corresponded to different hospital centers in different cities from the participating countries, sampling was non-random. Healthcare professionals in Latin America may face more difficulties than those from other countries, with 7 out of 10 professionals reporting that they did not have the necessary resources to care for patients with COVID-19. Technical and logistical difficulties should be addressed in the event of a future outbreak, as they have a negative impact on healthcare workers. Clinical trial registration: NCT04486404

Heavy oil hydroprocessing requires catalysts with enhanced mesoporosity and moderate acidity. Mesostructured aluminum modified SBA-15 have been identified as suitable catalytic supports for sulfided phases employed in this process. In this work, a series of SBA-15 based materials were synthesized using hexane as a micellar swelling agent for pore widening. Particularly, the effect of the hexane to Pluronic P123 mass ratio on key properties was assessed. Among the synthesized materials, the one prepared with a hexane: P123 mass ratio of 3.5 showed the best textural properties: BET surface area = 499 m 2  × g −1 , total pore volume = 1.8 cm 3  × g −1 , and average pore diameter = 27 nm. The acidity of this material was further modified by grafting aluminum over it. The resulting materials were employed as supports for sulfided Fe–W tested in the hydroprocessing of phenanthrene at 11 MPa and 623 K. Catalysts activity was found to related to the dispersion of the oxide precursor of the active metals which in turn was dependent on Al/Si molar ratio of the supports. Catalysts promoted the formation of 9,10-dihydrophenanthrene, a reaction intermediary in phenanthrene hydroprocessing. The catalyst with an Al/Si molar ratio of 0.04 showed the highest selectivity to this compound. The latter was correlated to a higher content of tetrahedral aluminum in the support. In general, the modifications performed over the SBA-15 support enhanced their pore size distributions and acidity and promoted the selective partial hydrogenation for the central ring of phenanthrene. The findings are important for the search of new catalysts in heavy oil hydroprocessing. Graphical Abstract

Teaching is an activity that requires understanding the class’s reaction to evaluate the teaching methodology effectiveness. This operation can be easy to achieve in small classrooms, while it may be challenging to do in classes of 50 or more students. This paper proposes a novel Internet of Things (IoT) system to aid teachers in their work based on the redundant use of non-invasive techniques such as facial expression recognition and physiological data analysis. Facial expression recognition is performed using a Convolutional Neural Network (CNN), while physiological data are obtained via Photoplethysmography (PPG). By recurring to Russel’s model, we grouped the most important Ekman’s facial expressions recognized by CNN into active and passive. Then, operations such as thresholding and windowing were performed to make it possible to compare and analyze the results from both sources. Using a window size of 100 samples, both sources have detected a level of attention of about 55.5% for the in-presence lectures tests. By comparing results coming from in-presence and pre-recorded remote lectures, it is possible to note that, thanks to validation with physiological data, facial expressions alone seem useful in determining students’ level of attention for in-presence lectures.