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Among the most revolutionary insights emerging from 200 years of research on dinosaurs is that the clade Dinosauria is represented by approximately 11 000 living species of birds. Although the origin of birds among dinosaurs has been reviewed extensively, recent years have witnessed tremendous progress in our understanding of the deep evolutionary origins of numerous distinctive avian anatomical systems. These advances have been enabled by exciting new fossil discoveries, leading to an ever-expanding phylogenetic framework with which to pinpoint the origins of characteristic avian features. The present review focuses on four notable avian systems whose Mesozoic evolutionary history has been greatly clarified by recent discoveries: brain, kinetic palate, pectoral girdle and postcranial skeletal pneumaticity.

Spectrally-resolved single-molecule localization microscopy (srSMLM) has emerged as a powerful tool for exploring the spectral properties of single emitters in localization microscopy. By simultaneously capturing the spatial positions and spectroscopic signatures of individual fluorescent molecules, srSMLM opens up the possibility of investigating an additional dimension in super-resolution imaging. However, appropriate and dedicated tools are required to fully capitalize on the spectral dimension. Here, we propose the application of the spectral phasor analysis as an effective method for summarizing and analyzing the spectral information obtained from srSMLM experiments. The spectral phasor condenses the complete spectrum of a single emitter into a two-dimensional space, preserving key spectral characteristics for single-molecule spectral exploration. We demonstrate the effectiveness of spectral phasor in efficiently classifying single Nile Red fluorescence emissions from largely overlapping cyanine fluorescence signals in dual-color PAINT experiments. Additionally, we employed spectral phasor with srSMLM to reveal subtle alterations occurring in the membrane of Gram-positive Enterococcus hirae in response to gramicidin exposure, a membrane-perturbing antibiotic treatment. Spectral phasor provides a robust, model-free analytic tool for the detailed analysis of the spectral component of srSMLM, enhancing the capabilities of multi-color spectrally-resolved single-molecule imaging., (© 2024 The Authors. ChemPhysChem published by Wiley-VCH GmbH.)

Case: A child with Type IV Osteogenesis Imperfecta (OI) sustained a growth arrest of the distal femur after fixation of a left femur fracture with a Fassier-Duval expanding rod at 3 years old. Despite bar resection with fat interposition, the discrepancy progressed to 7.5 cm at maturity. Because the femur had grown to a sufficient diameter, he underwent successful lengthening with a magnetic intramedullary rod., Conclusion: Although it is a potential complication, growth arrest has not been reported in association with placement of an expanding nail in a child with osteogenesis imperfecta. This case illustrates this rare complication and treatment using a magnetic intramedullary rod., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/C222)., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

A 12-year-old girl developed a distal femoral shaft fracture treated with lateral trochanteric entry intramedullary nail fixation. The nail was retained after union because of a persistent nonossifying fibroma at the previous fracture site. At 16 months after surgery, marked valgus deformity was noted at the distal femur, with signs of implant haloing and loosening, suggesting repetitive motion and stress concentration of forces at the distal femur. Owing to recognition before skeletal maturity, the valgus was corrected with hemiepiphysiodesis. This finding illustrates the importance of follow-up up to skeletal maturity for pediatric femoral shaft fractures and consideration of routine removal of implants after fracture union to avoid this previously unreported complication., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Background: Our 2 previous studies (1999, 2007) examining misrepresentation of research publications among orthopaedic residency applicants revealed rates of misrepresentation of 18.0% and 20.6%, respectively. As the residency selection process has become more competitive, the number of applicants who list publications has increased. The purpose of this study was to determine current rates of research misrepresentation by orthopaedic surgery applicants., Methods: We reviewed the publication listings and research section of the Common Application Form from the Electronic Residency Application Service (ERAS) for all applicants applying to 1 orthopaedic residency program. The PubMed-MEDLINE database was principally used to search for citations. The PubMed Identifier (PMID) number was used; if no PMID number was listed, a combination of authors or the title of the work was used. If the citations were not found through PubMed, a previously developed algorithm was followed to determine misrepresentation. Misrepresentation was defined as (1) nonauthorship of a published article in which authorship was claimed, (2) claimed authorship of a nonexistent article, or (3) self-promotion to a higher authorship status within a published article., Results: Five hundred and seventy-three applicants applied to our institution for residency in 2016 to 2017: 250 (43.6%) of 573 applicants did not list a publication, whereas 323 (56.4%) of 573 applicants listed ≥1 publication. We found 13 cases of misrepresentation among a total of 1,100 citations (1.18% in 2017 versus 18.0% in 1999 and 20.6% in 2007, p < 0.001). Ten cases of misrepresentation were self-promotion to a higher authorship status. There were 2 cases of claimed authorship of an article that could not be found. Only 1 applicant misrepresented more than once., Conclusions: Based on our findings, orthopaedic surgery residency applicants are accurately representing their publication information. The incorporation of the PMID number on the ERAS application has streamlined the process for finding publications, and has possibly encouraged veracity on residency applications. Faculty involved in the resident selection process should be aware of the significant decline in the rate of misrepresentation by medical students applying for orthopaedic surgery residency versus the rate in our prior studies.

Antimicrobial peptides are promising therapeutic alternatives to counter growing antimicrobial resistance. Their precise mechanism of action remains elusive, however, particularly with respect to live bacterial cells. We investigated the interaction of a fluorescent melittin analogue with single giant unilamellar vesicles, giant multilamellar vesicles, and bilamellar Gram-negative Escherichia coli (E. coli) bacteria. Time-lapse fluorescence lifetime imaging microscopy was employed to determine the population distribution of the fluorescent melittin analogue between pore state and membrane surface state, and simultaneously measure the leakage of entrapped fluorescent species from the vesicle (or bacterium) interior. In giant unilamellar vesicles, leakage from vesicle interior was correlated with an increase in level of pore states, consistent with a stable pore formation mechanism. In giant multilamellar vesicles, vesicle leakage occurred more gradually and did not appear to correlate with increased pore states. Instead pore levels remained at a low steady-state level, which is more in line with coupled equilibria. Finally, in single bacterial cells, significant increases in pore levels were observed over time, which were correlated with only partial loss of cytosolic contents. These observations suggested that pore formation, as opposed to complete dissolution of membrane, was responsible for the leakage of contents in these systems, and that the bacterial membrane has an adaptive capacity that resists peptide attack. We interpret the three distinct pore dynamics regimes in the context of the increasing physical and biological complexity of the membranes.

The interaction dynamics between a lytic peptide and a biomembrane was studied using time-lapse fluorescence lifetime imaging microscopy. The model membrane was 1,2-dipalmitoyl-sn-glycero-3-phosphochloine giant unilamellar vesicles (GUVs), and the peptide was the K14 derivative of melittin, to which the polarity-sensitive fluorescent probe AlexaFluor 430 was grafted. The interaction of the peptide with the GUVs resulted in a progressive quenching of the fluorescence lifetime over a period of minutes. From previous photophysics characterization of the peptide, we were able to deconvolve the contribution of three distinct peptide states to the lifetime trajectory and use this data to develop a kinetics model for the interaction process. It was found that the peptide-membrane interaction was well described by a two-step mechanism: peptide monomer adsorption followed by membrane surface migration, assembly, and insertion to form membrane pores. There was an equilibrium exchange between pore and surface monomers at all lipid/peptide (L/P) concentration ratios, suggesting that the fully inserted phase was reached, even at low peptide concentrations. In contrast to previous studies, there was no evidence of critical behavior; irrespective of L/P ratio, lytic pores were the dominant peptide state at equilibrium and were formed even at very low peptide concentrations. We suggest that this behavior is seen in GUVs because their low curvature means low Laplace pressure. Membrane elasticity is therefore relatively ineffective at damping the thermal fluctuations of lipid molecules that lead to random molecular-level lipid protrusions and membrane undulations. The transient local membrane deformations that result from these thermal fluctuations create the conditions necessary for facile peptide insertion.

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

In late December 1990, a new radio source appeared near the center of our galaxy rivaling the intensity of Sgr A(*) (the compact radio source at the galactic center). Following its first detection, the flux density of the galactic center transient (GCT) increased rapidly to a maximum 1 month later, and then declined gradually with a time scale of about 3 months. Surprisingly, the GCT maintained a steep radio spectrum during both its rising and decay phases. The neutral hydrogen (HI) absorption shows similar absorption to that in front of Sgr A(*); this indicates that the GCT lies near the galactic center. Furthermore, both HI and OH observations show an additional deep absorption at +20 kilometers per second with respect to the local standard of rest. Thus, the GCT is either embedded in or located behind a molecular cloud moving with that velocity. The cloud can be seen on infrared images. Its opacity is shown to be inadequate to conceal a supernova near the galactic center. It is argued that the GCT was probably transient radio emission from synchrotron-radiating plasma associated with an x-ray binary system.