The high optical brightness of the BlueWalker 3 satellite.

Large constellations of bright artificial satellites in low Earth orbit pose significant challenges to ground-based astronomy1. Current orbiting constellation satellites have brightnesses between apparent magnitudes 4 and 6, whereas in the near-infrared Ks band, they can reach magnitude 2 (ref. 2). Satellite operators, astronomers and other users of the night sky are working on brightness mitigation strategies3,4. Radio emissions induce further potential risk to ground-based radio telescopes that also need to be evaluated. Here we report the outcome of an international optical observation campaign of a prototype constellation satellite, AST SpaceMobile's BlueWalker 3. BlueWalker 3 features a 64.3 m2 phased-array antenna as well as a launch vehicle adaptor (LVA)5. The peak brightness of the satellite reached an apparent magnitude of 0.4. This made the new satellite one of the brightest objects in the night sky. Additionally, the LVA reached an apparent V-band magnitude of 5.5, four times brighter than the current International Astronomical Union recommendation of magnitude 7 (refs. 3,6); it jettisoned on 10 November 2022 (Universal Time), and its orbital ephemeris was not publicly released until 4 days later. The expected build-out of constellations with hundreds of thousands of new bright objects1 will make active satellite tracking and avoidance strategies a necessity for ground-based telescopes.

Dissection and Isolation of Region-Specific Decellularized Lung Tissue.

Lung transplantation is often the only option for patients in the later stages of severe lung disease, but this is limited both due to the supply of suitable donor lungs and both acute and chronic rejection after transplantation. Ascertaining novel bioengineering approaches for the replacement of diseased lungs is imperative for improving patient survival and avoiding complications associated with current transplantation methodologies. An alternative approach involves the use of decellularized whole lungs lacking cellular constituents that are typically the cause of acute and chronic rejection. Since the lung is such a complex organ, it is of interest to examine the extracellular matrix components of specific regions, including the vasculature, airways, and alveolar tissue. The purpose of this approach is to establish simple and reproducible methods by which researchers may dissect and isolate region-specific tissue from fully decellularized lungs. The current protocol has been devised for pig and human lungs, but may be applied to other species as well. For this protocol, four regions of the tissue were specified: airway, vasculature, alveoli, and bulk lung tissue. This procedure allows for the procurement of samples of tissue that more accurately represent the contents of the decellularized lung tissue as opposed to traditional bulk analysis methods.

Regional and disease-specific glycosaminoglycan composition and function in decellularized human lung extracellular matrix.

Decellularized lung scaffolds and hydrogels are increasingly being utilized in ex vivo lung bioengineering. However, the lung is a regionally heterogenous organ with proximal and distal airway and vascular compartments of different structures and functions that may be altered as part of disease pathogenesis. We previously described decellularized normal whole human lung extracellular matrix (ECM) glycosaminoglycan (GAG) composition and functional ability to bind matrix-associated growth factors. We now determine differential GAG composition and function in airway, vascular, and alveolar-enriched regions of decellularized lungs obtained from normal, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF) patients. Significant differences were observed in heparan sulfate (HS), chondroitin sulfate (CS), and hyaluronic acid (HA) content and CS/HS compositions between both different lung regions and between normal and diseased lungs. Surface plasmon resonance demonstrated that HS and CS from decellularized normal and COPD lungs similarly bound fibroblast growth factor 2, but that binding was decreased in decellularized IPF lungs. Binding of transforming growth factor ß to CS was similar in all three groups but binding to HS was decreased in IPF compared to normal and COPD lungs. In addition, cytokines dissociate faster from the IPF GAGs than their counterparts. The differences in cytokine binding features of IPF GAGs may result from different disaccharide compositions. The purified HS from IPF lung is less sulfated than that from other lungs, and the CS from IPF contains more 6-O-sulfated disaccharide. These observations provide further information for understanding functional roles of ECM GAGs in lung function and disease. STATEMENT OF SIGNIFICANCE: Lung transplantation remains limited due to donor organ availability and need for life-long immunosuppressive medication. One solution, the ex vivo bioengineering of lungs via de- and recellularization has not yet led to a fully functional organ. Notably, the role of glycosaminoglycans (GAGs) remaining in decellularized lung scaffolds is poorly understood despite their important effects on cell behaviors. We have previously investigated residual GAG content of native and decellularized lungs and their respective functionality, and role during scaffold recellularization. We now present a detailed characterization of GAG and GAG chain content and function in different anatomical regions of normal diseased human lungs. These are novel and important observations that further expand knowledge about functional GAG roles in lung biology and disease.

Regional and disease specific human lung extracellular matrix composition.

Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), are characterized by regional extracellular matrix (ECM) remodeling which contributes to disease progression. Previous proteomic studies on whole decellularized lungs have provided detailed characterization on the impact of COPD and IPF on total lung ECM composition. However, such studies are unable to determine the differences in ECM composition between individual anatomical regions of the lung. Here, we employ a post-decellularization dissection method to compare the ECM composition of whole decellularized lungs (wECM) and specific anatomical lung regions, including alveolar-enriched ECM (aECM), airway ECM (airECM), and vasculature ECM (vECM), between non-diseased (ND), COPD, and IPF human lungs. We demonstrate, using mass spectrometry, that individual regions possess a unique ECM signature characterized primarily by differences in collagen composition and basement-membrane associated proteins, including ECM glycoproteins. We further demonstrate that both COPD and IPF lead to alterations in lung ECM composition in a region-specific manner, including enrichment of type-III collagen and fibulin in IPF aECM. Taken together, this study provides methodology for future studies, including isolation of region-specific lung biomaterials, as well as a dataset that may be applied for the identification of novel ECM targets for therapeutics.

A "basket of care" for heart failure patients managing at home: evaluating a community-based nursing intervention from a patient's perspective.

BACKGROUND: Patients with heart failure (HF) in the community represent a large and growing patient population whose complex care requires implementation of innovative care modalities. The Centre Hospitalier--Centre de Sante et de Services Sociaux--Corridor of Service for Heart Failure Patients (CH-CSSS-CSHFP) represents a novel approach to address the challenges of delivering comprehensive care to HF patients in the community. PURPOSE: In this study, the researchers aimed to answer the question: What is the patient's perception of care received in the CH-CSSS-CSHFP? METHOD: A descriptive qualitative design and semistructured interviews guided the inquiry. SAMPLE: A convenience sample (n=5) of HF patients was recruited from five community health centres. RESULTS: Themes that arose from analysis included "Staying home": A shared goal of the patient and service, "Checking on": Health-related monitoring, and "Being connected": Ties to the health care system. CONCLUSION: Results of this study provide insight into the patient's unique perspective on how this service has impacted his/her HF management and may assist health care professionals in designing more effective community-based services.

The effect of ball-carrying technique and experience on sprinting in rugby union.

There are several ways of carrying the ball in rugby union, which could influence the speed at which a player can run. We assessed 52 rugby players (34 males, 18 females) during a maximum sprint over 30 m without the ball, with the ball under one arm, and with the ball in both hands. Timing gates were used to measure time over the initial 10 m and the last 20 m. It has previously been reported (Grant et al., 2003) that running with the ball produces a slower sprinting speed than running without the ball. We hypothesized that the decrease in speed caused by carrying the ball would become less marked with the experience of the player. The male and female players were each divided into two groups: a "beginner" group that consisted of players in their first or second season and an "experienced" group that was composed of players who had played for more than two seasons. A 2 x 3 mixed-model analysis of variance was used to identify differences (P < 0.01) between the beginner and experienced groups in the three sprinting conditions. The times for the males for the first 10 m sprints without the ball, with the ball under one arm, and with the ball in both hands were 1.87 +/- 0.08 s, 1.87 +/- 0.08 s, and 1.91 +/- 0.1 s for the beginners, and 1.87 +/- 0.1, 1.88 +/- 0.1 and 1.88 +/- 0.12 for the more experienced players respectively. The times for the females for the first 10 m without the ball, with the ball under one arm, and with the ball in both hands were 2.13 +/- 0.16 s, 2.19 +/- 0.17 s, and 2.20 +/- 0.16 s for the beginners, and 2.03 +/- 0.12 s, 2.03 +/- 0.09 s, and 2.04 +/- 0.1 s for the more experienced players respectively. For the last 20 m of the 30-m sprint, there were differences between the different sprint conditions (P < 0.001) but no differences that were attributable to experience (P = 0.297). The times for the males over the last 20 m without the ball, with the ball under one arm, and with the ball in both hands were 2.58 +/- 0.19 s, 2.61 +/- 0.12 s, and 2.65 +/- 0.12 s for the beginners, and 2.59 +/- 0.12, 2.62 +/- 0.23, and 2.65 +/- 0.18 s for the more experienced players respectively. The times for the females over the last 20 m without the ball, with the ball under one arm, and with the ball in both hands were 3.25 +/- 0.38 s, 3.35 +/- 0.42 s, and 3.40 +/- 0.46 s for the beginners, and 3.04 +/- 0.32 s, 3.06 +/- 0.22 s, and 3.13 +/- 0.27 s for the more experienced players respectively. No gender-specific differences were detected. The results of this study suggest that practising sprints while carrying a ball benefits the early phase of sprinting while carrying the ball.

Cascading effects of over-fishing marine systems.

Profound indirect ecosystem effects of over-fishing have been shown for coastal systems such as coral reefs and kelp forests. A new study from the ecosystem off the Canadian east coast now reveals that the elimination of large predatory fish can also cause marked cascading effects on the pelagic food web. Overall, the view emerges that, in a range of marine ecosystems, the effects of fisheries extend well beyond the collapse of fish exploited stocks.

Structural requirements of MLD-containing disintegrins for functional interaction with alpha 4 beta 1 and alpha 9 beta1 integrins.

Three non-RGD-containing disintegrins, VLO5, EO5, and EC3, belong to the heterodimeric family of these snake venom-derived proteins. They are potent inhibitors of certain leukocyte integrins such as alpha4beta1, alpha4beta7, and alpha9beta1, and act through the MLD motif present in one of their subunits. However, the selectivity of these disintegrins to interact with integrins is related to the amino acid composition of the integrin-binding loop in the MLD-containing subunit. The most important amino acid is that preceding the MLD motif. In vitro experiments in adhesion and ELISA assays revealed that the TMLD-containing disintegrins, VLO5 and EO5, appeared to be very potent inhibitors of human alpha4beta1 and alpha9beta1 and less effective in inhibition of the alpha4beta7 integrin. The reverse effect was observed for the AMLD-containing disintegrin, EC3. The data with native disintegrins were confirmed by experiments with synthetic peptides displaying TMLD and AMLD motifs. The MLD-containing disintegrins showed differential activities to inhibit human and murine alpha4beta1 integrin. EC3 was a weaker inhibitor of human integrin, whereas VLO5 and EO5 less actively inhibited murine alpha4beta1. These data describe a useful set of potent and selective integrin antagonists and suggest conformational requirements of human and mouse integrins for interaction with ligands.