Taphonomic experiments resolve controls on the preservation of melanosomes and keratinous tissues in feathers

Fossils are a key source of data on the evolution of feather structure and function through deep time, but their ability to resolve macroevolutionary questions is compromised by an incomplete understanding of their taphonomy. Critically, the relative preservation potential of two key feather components, melanosomes and keratinous tissue, is not fully resolved. Recent studies suggesting that melanosomes are preferentially preserved conflict with observations that melanosomes preserve in fossil feathers as external moulds in an organic matrix. To date, there is no model to explain the latter mode of melanosome preservation. We addressed these issues by degrading feathers in systematic taphonomic experiments incorporating decay, maturation and oxidation in isolation and combination. Our results reveal that the production of mouldic melanosomes requires interactions with an oxidant and is most likely to occur prior to substantial maturation. This constrains the taphonomic conditions under which melanosomes are likely to be fossilized. Critically, our experiments also confirm that keratinous feather structures have a higher preservation potential than melanosomes under a range of diagenetic conditions, supporting hitherto controversial hypotheses that fossil feathers can retain degraded keratinous structures

Global, regional, and national burden of osteoarthritis, 1990–2020 and projections to 2050: a systematic analysis for the Global Burden of Disease Study 2021

Background Osteoarthritis is the most common form of arthritis in adults, characterised by chronic pain and loss of mobility. Osteoarthritis most frequently occurs after age 40 years and prevalence increases steeply with age. WHO has designated 2021–30 the decade of healthy ageing, which highlights the need to address diseases such as osteoarthritis, which strongly affect functional ability and quality of life. Osteoarthritis can coexist with, and negatively effect, other chronic conditions. Here we estimate the burden of hand, hip, knee, and other sites of osteoarthritis across geographies, age, sex, and time, with forecasts of prevalence to 2050. Methods In this systematic analysis for the Global Burden of Disease Study, osteoarthritis prevalence in 204 countries and territories from 1990 to 2020 was estimated using data from population-based surveys from 26 countries for knee osteoarthritis, 23 countries for hip osteoarthritis, 42 countries for hand osteoarthritis, and US insurance claims for all of the osteoarthritis sites, including the other types of osteoarthritis category. The reference case definition was symptomatic, radiographically confirmed osteoarthritis. Studies using alternative definitions from the reference case definition (for example self-reported osteoarthritis) were adjusted to reference using regression models. Osteoarthritis severity distribution was obtained from a pooled meta-analysis of sources using the Western Ontario and McMaster Universities Arthritis Index. Final prevalence estimates were multiplied by disability weights to calculate years lived with disability (YLDs). Prevalence was forecast to 2050 using a mixed-effects model. Findings Globally, 595 million (95% uncertainty interval 535–656) people had osteoarthritis in 2020, equal to 7·6% (95% UI 6·8–8·4) of the global population, and an increase of 132·2% (130·3–134·1) in total cases since 1990. Compared with 2020, cases of osteoarthritis are projected to increase 74·9% (59·4–89·9) for knee, 48·6% (35·9–67·1) for hand, 78·6% (57·7–105·3) for hip, and 95·1% (68·1–135·0) for other types of osteoarthritis by 2050. The global age-standardised rate of YLDs for total osteoarthritis was 255·0 YLDs (119·7–557·2) per 100 000 in 2020, a 9·5% (8·6–10·1) increase from 1990 (233·0 YLDs per 100 000, 109·3–510·8). For adults aged 70 years and older, osteoarthritis was the seventh ranked cause of YLDs. Age-standardised prevalence in 2020 was more than 5·5% in all world regions, ranging from 5677·4 (5029·8–6318·1) per 100 000 in southeast Asia to 8632·7 (7852·0–9469·1) per 100 000 in high-income Asia Pacific. Knee was the most common site for osteoarthritis. High BMI contributed to 20·4% (95% UI –1·7 to 36·6) of osteoarthritis. Potentially modifiable risk factors for osteoarthritis such as recreational injury prevention and occupational hazards have not yet been explored in GBD modelling. Interpretation Age-standardised YLDs attributable to osteoarthritis are continuing to rise and will lead to substantial increases in case numbers because of population growth and ageing, and because there is no effective cure for osteoarthritis. The demand on health systems for care of patients with osteoarthritis, including joint replacements, which are highly effective for late stage osteoarthritis in hips and knees, will rise in all regions, but might be out of reach and lead to further health inequity for individuals and countries unable to afford them. Much more can and should be done to prevent people getting to that late stage

The taphonomy of feathers

Fossil feathers harbour key information for understanding the evolution of feathers through deep time. The ability of fossil feathers to inform on the biochemical evolution of feathers is, however, restricted due to an incomplete understanding of feather taphonomy. Accurate interpretation of data from fossil feathers requires a comprehensive understanding of the fate of key feather components – melanosomes, melanins and feather corneous beta proteins (CBPs) – during fossilization, but this is not fully characterized. Further, whether the preservation of different feather components is inter-dependent, and whether certain components impact preservation of others, is unknown. Unsurprisingly, reports of preserved feather chemistry in fossils are controversial. This thesis addresses these issues using taphonomic experiments incorporating decay, sulfurisation, oxidation, thermal maturation and high temperature-high pressure maturation on black, white and orange feathers from extant birds. The results resolve the controls on the preservation of melanosomes and melanins (in decreasing order of importance: oxidation, maturation and decay) and the proteinaceous component of feathers (in decreasing order of importance: maturation, oxidation and decay). The experimental results also support new fossil evidence for the preservation of disulfides and amides, which are indicative of feather CBPs, in Mesozoic fossil feathers and the preservation of phaeomelanin molecular residues in Miocene fossil frogs. Collectively, the results form the basis for a new integrated model for feather preservation that is firmly grounded in quantitative empirical data and encompasses all major feather components. This model explains variations in the preservation of fossil feathers and represents a major advance in our understanding of the preservation of feathers and of structural proteins. Critically, the model highlights the power of combining systematic and quantitative taphonomic experiments with a holistic, whole-tissue approach, to resolve long-standing issues relating to the preservation of soft tissues in the fossil record

Preservation of corneous beta proteins in Mesozoic feathers

S-XANES data. Small samples (≥3 mm2) of untreated and experimentally degraded feathers in addition to fossil material and samples of host sediment were placed on low-sulfur mylar tape and analyzed at the Stanford Synchrotron Radiation Lightsource (SSRL) using synchrotron X-ray absorption near-edge spectroscopy (XANES) at beam line 6-2. S-XANES data were collected in fluorescence mode using a single element Vortex silicon drift detector set at an angle of ~90° to the incident beam to minimize the scatter signal. The incident x-ray energy was selected using a Si(111) monochromator, which was calibrated using a Na2S2O3 standard with the thiol pre-edge peak defined as 2472.02 eV. S-XANES standards for selected S-bearing compounds, representing different S species, were prepared by mixing commercially available analytical standards (Sigma Aldrich; ≥98% pure) with BN to obtain a S concentration of ca. 5 wt% in each standard. Data alignment, averaging, background subtraction and normalisation were performed using Athena v. 0.9.26. FTIR data. Fossil data were collected in the 4000–600 cm-1 range using a PerkinElmer Frontier FTIR spectrometer fitted with a Spotlight 400 microscope. Each spectrum was collected as an average of 8–36 scans. Spectra for untreated and matured feathers were collected in the 4000–500 cm-1 range using a universal diamond ATR accessory on the Frontier spectrometer. Each spectrum was collected as an average of 10 scans. Each spectrum was baseline-corrected using SpectraGryph v. 1.2.7 using the parameters adaptive correction, 15% coarseness and no offset. In addition, interactive baseline correction was performed on data in the region 898–450 cm-1 using Spectrum IR v. 10.6.1 (PerkinElmer, USA). This ensured a consistent baseline across the entire scan range to facilitate spectral comparison. Each spectrum was standardized to remove sample thickness effects.The software package Athena is required to open all X-ray absorption spectroscopy data in .prj files and is available in the Demeter software suite. Spectragryph software is required to open all Fourier transform infrared spectroscopy data in .sp and .spc files. OriginPro is required to open all deconvolution data in .opju files. This study was also supported by the Irish Research Council New Foundations award

The availability of community ties predicts likelihood of peer referral for mammography: Geographic constraints on viral marketing

Engaging social networks to encourage preventive health behavior offers a supplement to conventional mass media campaigns and yet we do not fully understand the conditions that facilitate or hamper such interpersonal diffusion. One set of factors that should affect the diffusion of health campaign information involves a person's community. Variables describing geographic communities should predict the likelihood of residents accepting campaign invitations to pass along information to friends, family, and others. We investigate two aspects of a community - the availability of community ties and residential stability-as potential influences on diffusion of publicly-funded breast cancer screening in the United States in 2008-2009. In a survey study of 1515 participants living in 91 zip codes across the State of Minnesota, USA, we focus on the extent to which women refer others when given the opportunity to nominate family, friends, and peers to receive free mammograms. We predicted nomination tendency for a particular zip code would be a function of available community ties, measured as religious congregation density in that zip code, and also expected the predictive power of available ties would be greatest in communities with relatively high residential stability (meaning lower turnover in home residence). Results support our hypotheses. Congregation density positively predicted nomination tendency both in bivariate analysis and in Tobit regression models, and was most predictive in zip codes above the median in residential stability. We conclude that having a local infrastructure of social ties available in a community predicts the diffusion of available health care services in that community.USA Campaign Mammography Peer referral Social capital Social networks Geography Cancer communication Screening