Impact of Aerogel Modification for Fe-N-C Activity and Stability towards Oxygen Reduction Reaction in Phosphoric Acid Electrolyte.

Resorcinol-formaldehyde based carbon aerogel (CA) has been tailored to meet the requirements as a Fe-N-C carbon support, aiming to provide sufficient, inexpensive cathode catalysts for high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Therefore, different treatments of the aerogel are explored for optimal pore structure and incorporation of surface functionalities, which are crucial for Fe-N-C synthesis and electrochemical performance. Fe-N-Cs of differently modified aerogel are investigated in phosphoric acid electrolyte.

Unique functional diversity during early Cenozoic mammal radiation of North America.

Mammals influence nearly all aspects of energy flow and habitat structure in modern terrestrial ecosystems. However, anthropogenic effects have probably altered mammalian community structure, raising the question of how past perturbations have done so. We used functional diversity (FD) to describe how the structure of North American mammal palaeocommunities changed over the past 66 Ma, an interval spanning the radiation following the K/Pg and several subsequent environmental disruptions including the Palaeocene-Eocene Thermal Maximum (PETM), the expansion of grassland, and the onset of Pleistocene glaciation.

Physiological determinants of decreased peak leg oxygen uptake in chronic disease: a systematic review and meta-analysis.

This systematic review and meta-analysis examined the physiological mechanisms responsible for lower peak exercise leg oxygen uptake (V̇o) in patients with chronic disease. Studies measuring peak leg V̇o (primary outcome) and its physiological determinants during large (cycle) or small muscle mass exercise (single-leg knee extension, SLKE) in patients with chronic disease were included in this meta-analysis. Pooled estimates for each outcome were reported as a weighted mean difference (WMD) between chronic disease and controls.

Endurance exercise training changes the limitation on muscle in normoxia from the capacity to utilize O to the capacity to transport O.

Maximal oxygen (O ) uptake ( ) is an important parameter with utility in health and disease. However, the relative importance of O transport and utilization capacities in limiting muscle before and after endurance exercise training is not well understood. Therefore, the present study aimed to identify the mechanisms determining muscle pre- and post-endurance exercise training in initially sedentary participants.

Blood Gas Transport: Implications for O2 and CO2 Exchange in Lungs and Tissues.

The well-known ways in which O and CO (and other gases) are carried in the blood were presented in the preceding chapter. However, what the many available texts about O and CO transport do not emphasize is why knowing how gases are carried in blood matters, and this second, companion, article specifically addresses that critical aspect of gas exchange physiology. During gas exchange, both at the lungs and in the peripheral tissues, it is the shapes and the slopes of the O and CO binding curves that explain almost all of the behaviors of each gas and the quantitative differences observed between them.

Blood Gas Transport: Carriage of Oxygen and Carbon Dioxide in Blood.

The ways in which oxygen (O) and carbon dioxide (CO) are carried in the blood are well known and well understood, with a plethora of textbooks, both general and lung specific, all presenting the topic in a very similar manner. This first of two companion chapters similarly summarizes this information. First, carriage of gases by physical solution is described, followed by discussion of O, carbon monoxide, and CO transport in that order.

Combination of hyperoxia and a right-shifted HbO dissociation curve delays V̇o kinetics during maximal contractions in isolated muscle.

Acute enhancement of peripheral O diffusion may accelerate skeletal muscle O uptake (V̇o) kinetics and lessen fatigue during transitions from rest to maximal contractions. Surgically isolated canine gastrocnemius muscles in situ ( = 6) were studied during transitions from rest to 4 min of electrically stimulated isometric tetanic contractions at V̇o, in two conditions: normoxia (CTRL) and hyperoxia ([Formula: see text] = 1.00) + administration of a drug (RSR-13), which right shifts the Hb-O dissociation curve (Hyperoxia + RSR-13).

Metabolic Silencing via Methionine-Based Amino Acid Restriction in Head and Neck Cancer.

In recent years, various forms of caloric restriction (CR) and amino acid or protein restriction (AAR or PR) have shown not only success in preventing age-associated diseases, such as type II diabetes and cardiovascular diseases, but also potential for cancer therapy. These strategies not only reprogram metabolism to low-energy metabolism (LEM), which is disadvantageous for neoplastic cells, but also significantly inhibit proliferation. Head and neck squamous cell carcinoma (HNSCC) is one of the most common tumour types, with over 600,000 new cases diagnosed annually worldwide.

Objective Quantification and Topographic Dioptric Demand of Near-Work.

Purpose: The assessment of myopigenic environmental risk factors such as near-work relies on subjective data. Although diaries and questionnaires on near-work show correlation to some degree, it remains unknown how they may correspond to ground truth. This is an important consideration because valid estimates of near-work have great utility for understanding the mechanisms by which dioptric demand drives excessive eye-growth, which is not yet entirely understood.

Three-dimensional free-standing gold nanowire networks as a platform for catalytic applications.

We report the catalytic performance of networks of highly interconnected Au nanowires with diameters tailored between 80 and 170 nm. The networks were synthesized by electrodeposition in etched ion-track polymer templates, and the synthesis conditions were developed for optimal wire crystallinity and network homogeneity. The nanowire networks were self-supporting and could be easily handled as electrodes in electrochemical cells or other devices.

Improving population-level refractive error monitoring via mixture distributions.

Introduction: Sampling and describing the distribution of refractive error in populations is critical to understanding eye care needs, refractive differences between groups and factors affecting refractive development. We investigated the ability of mixture models to describe refractive error distributions.

Methods: We used key informants to identify raw refractive error datasets and a systematic search strategy to identify published binned datasets of community-representative refractive error.

Reply: Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery.

https://bit.ly/3Fypdwz

Towards the Reduction of Pt Loading in High Temperature Proton Exchange Membrane Fuel Cells - Effect of Fe-N-C in Pt-Alloy Cathodes.

Pt poisoning by phosphate in high temperature proton exchange membrane fuel cells (HT-PEMFC) leads to loadings up to 1 mg  cm per electrode of costly materials. While cheaper Fe-N-C catalysts are unaffected by phosphate deactivation and contribute to the catalysis of the oxygen reduction reaction, their volumetric activity is substantially lower. In this study, the effect of Pt-loading reduced hybrid cathodes for HT-PEMFC is investigated using commercial Celtec®-P-based assembling.

Determinants of maximal oxygen consumption.

This article lays out the determinants of maximal O consumption (VOmax) achieved during high intensity endurance exercise. It is not a traditional topical review but rather an educational essay that intertwines chance observations made during an unrelated research project with a subsequent program of stepwise thought, analysis and experimentation to reveal how O is delivered to and used by the mitochondria. The centerpiece is the recognition that O is delivered by an inter-dependent system of transport components functioning as a "bucket brigade", made up of the lungs, heart, blood and circulation, and the muscles themselves, each of which affects O transport by similar amounts as they change.

Preserved peak exercise capacity in Andean highlanders with excessive erythrocytosis both before and after isovolumic hemodilution.

In chronic mountain sickness (CMS), increased blood oxygen (O)-carrying capacity due to excessive erythrocytosis (EE, [Hb] ≥ 21 g/dL) could be offset, especially during exercise by both impaired cardiac output (Q̇t) and O diffusion limitation in lungs and muscle. We hypothesized that EE results in reduced peak V̇o despite increased blood O-carrying capacity, and that isovolumic hemodilution (IVHD) improves exercise capacity. In 14 male residents of Cerro de Pasco, Peru (4,340 m), six with and eight without EE, we measured peak cycle-exercise capacity, V̇o, Q̇t, arterial blood gas parameters, and (resting) blood volume.

Estimating 3D spatiotemporal point of regard: a device evaluation.

This paper presents and evaluates a system and method that record spatiotemporal scene information and location of the center of visual attention, i.e., spatiotemporal point of regard (PoR) in ecological environments.

Atomic-Scale Rectification and Inelastic Electron Tunneling Spectromicroscopy.

The phenomenon of rectification describes the emergence of a DC current from the application of an oscillating voltage. Although the origin of this effect has been associated with the nonlinearity in the current-voltage () relation, a rigorous understanding of the microscopic mechanisms for this phenomenon remains challenging. Here, we show the close connection between rectification and inelastic electron tunneling spectroscopy and microscopy for single molecules with a scanning tunneling microscope.

Intrapulmonary shunt and alveolar dead space in a cohort of patients with acute COVID-19 pneumonitis and early recovery.

Background: Pathological evidence suggests that coronavirus disease 2019 (COVID-19) pulmonary infection involves both alveolar damage (causing shunt) and diffuse microvascular thrombus formation (causing alveolar dead space). We propose that measuring respiratory gas exchange enables detection and quantification of these abnormalities. We aimed to measure shunt and alveolar dead space in moderate COVID-19 during acute illness and recovery.

Blinking and normal ocular surface in school-aged children and the effects of age and screen time.

Purpose: Baseline ocular surface characteristics in children require investigation. This study characterised blinking and relationships with ocular symptoms, tear film and digital device use.

Methods: 45 children aged 6-15 years (56% female) participated in a cross-sectional study.

Isovolemic hemodilution in chronic mountain sickness acutely worsens nocturnal oxygenation and sleep apnea severity.

Study Objectives: Chronic mountain sickness (CMS) is commonly observed among Andean and other highland populations. Sleep-disordered breathing (SDB) is highly prevalent at high altitude, and SDB and nocturnal hypoxemia have been observed in CMS. Phlebotomy is commonly performed to treat CMS, but it is unknown whether reducing hematocrit improves SDB.

Ergogenic value of oxygen supplementation in chronic obstructive pulmonary disease.

Patients with COPD exhibit limited exercise endurance time compared to healthy age-matched individuals. Oxygen supplementation is often applied to improve endurance time during pulmonary rehabilitation in patients with COPD and thus a comprehensive understanding of the mechanisms leading to improved endurance is desirable. This review analyses data from two studies by our research group investigating the effect of oxygen supplementation on cerebrovascular, systemic, respiratory and locomotor muscle oxygen availability on the same cohort of individuals with advanced COPD, and the mechanisms associated with improved endurance time in hyperoxia, which was essentially doubled (at the same power output).

Using pulmonary gas exchange to estimate shunt and deadspace in lung disease: theoretical approach and practical basis.

The common pulmonary consequence of SARS-CoV-2 infection is pneumonia, but vascular clot may also contribute to COVID pathogenesis. Imaging and hemodynamic approaches to identifying diffuse pulmonary vascular obstruction (PVO) in COVID (or acute lung injury generally) are problematic particularly when pneumonia is widespread throughout the lung and hemodynamic consequences are buffered by pulmonary vascular recruitment and distention. Although stimulated by COVID-19, we propose a generally applicable bedside gas exchange approach to identifying PVO occurring alone or in combination with pneumonia, addressing both its theoretical and practical aspects.