Mass Function Research Articles

From Halos to Galaxies. VI. Improved Halo Mass Estimation for SDSS Groups and Measurement of the Halo Mass Function

From Halos to Galaxies. VI. Improved Halo Mass Estimation for SDSS Groups and Measurement of the Halo Mass Function

Nebular and Nonthermal Radio Emissions for Young Stellar Populations with PARSEC v1.2s

Abstract In this paper, we compute, by means of the recently and thoroughly updated PARSE v1.2 s database of stellar nonrotating evolutionary tracks, the integrated stellar spectra, the ionizing photon budget, and the supernovae rates of young simple stellar populations (SSPs), for five metallicities between 0.0001 and 0.02 and four choices of stellar initial mass function (IMF) upper mass limits between 40 M ⊙ and 350 M ⊙. Using the photo-ionization code CLOUDY, we compute, at this same range of metallicities and limits, the intensities of some selected recombination and collisionally excited lines as a function of the age of the SSP. We account for the electron temperature dependence on IMF upper mass limit and metallicity while computing the thermal radio emission component, and also accounted for recent advances in core-collapse supernova explosion models while computing the nonthermal radio emission component. We self-consistently add the emission lines, nebular continuum, and nonthermal radio emission to the original SSP integrated photospheric spectra. Finally, from the resulting new suite of SSPs, we provide a consistent set of analytical relations between star formation rate (SFR) and ultraviolet, optical, and thermal radio luminosities that can be used to convert attenuation-corrected and dust-unaffected luminosities to SFR estimates. In a forthcoming paper, we will use our new SSP libraries as input to the state-of-the-art radiative transfer model GRAphites and SILicates to test the overall performance of these SSPs in reproducing the observed spectral energy distribution of young star-forming galaxies.

Life space restriction following disruptive life events: Evidence from the COVID-19 pandemic.

Restriction of life space mobility is associated with adverse health outcomes including depression, morbidity, mortality and poorer quality of life. In this study, we aimed to determine the impact of COVID-19 and associated employment loss on the life space of older adults in Singapore. An in-person survey was administered to a cohort of older Singaporeans above 50 years old (N = 1,118). Data collected included self-report measures of life space, sensory function, well-being, cognitive function, depression, frailty, and objective measures of muscle mass and body mass index. Tests of association and linear regression were performed to test the hypotheses, while accounting for the effects of health and sociodemographic covariates. The life space of older adults have significantly diminished after the pandemic. This loss remained significant despite controlling for covariates and was more pronounced amongst those who had lost employment during the pandemic. In addition, losing employment during the pandemic was associated with having smaller life spaces. Life space assessments are a potential important noninvasive marker for not only health and longevity, but the ability to sustain employment. Public health crises like the COVID-19 pandemic and employment loss negatively impacts the life spaces of older adults. It is needful to emphasize the maintenance of life space when faced with disruptive life events and provide multidisciplinary collaborative solutions to restore the quality of life amongst vulnerable older adults.

Clinical Competency in Managing Malnutrition–Sarcopenia Syndrome Among Physical Therapists: A Cross-Sectional Survey

Background/objectives: Malnutrition and sarcopenia are interrelated health concerns among the elderly. Each condition is associated with increased mortality, morbidity, rehospitalization rates, longer hospital stays, higher healthcare costs, and reduced quality of life. Their combination leads to the development of “Malnutrition–Sarcopenia Syndrome” (MSS), characterized by reductions in body weight, muscle mass, strength, and physical function. Despite being preventable and reversible through nutritional and physical interventions, the clinical competence of physical therapists (PTs) in managing MSS remains underexplored. This study aims to assess the clinical competency of PTs in MSS management. Methods: An anonymous cross-sectional survey was conducted from January to August 2024 among 337 certified PTs in Israel, using the “Qualtrics” platform. The survey assessed prior familiarity with MSS concepts, MSS knowledge levels, screening and treatment skills, attitudes and beliefs toward MSS management, and interprofessional collaboration practices. Results: While 52% of PTs were familiar with MSS, familiarity with diagnostic guidelines was low (EWGSOP2: 3.6%; GLIM: 0.6%). The MSS knowledge score was moderate, but screening and treatment skills were low. Attitudes toward MSS management were moderately positive, but self-belief in diagnosing and treating MSS was low. Interprofessional collaboration was limited, particularly in malnutrition care. PTs familiar with MSS had higher knowledge, better skills, more positive attitudes and beliefs, and greater interprofessional collaboration. Conclusions: Significant gaps exist in the clinical competency of Israeli PTs in MSS management. Integrating MSS content into physical therapy curricula and providing continuing professional development are necessary to enhance competencies. Equipping PTs with essential tools, clarifying roles, and promoting interprofessional collaboration can optimize MSS management and improve patient outcomes.

Variation of the low-mass end of the stellar initial mass function with redshift and metallicity

Abstract We report the stellar mass functions obtained from 20 radiation hydrodynamical simulations of star cluster formation in 500 M⊙ molecular clouds with metallicities of 3, 1, 1/10 and 1/100 of the solar value, with the clouds subjected to levels of the cosmic microwave background radiation that are appropriate for star formation at redshifts z = 0, 3, 5, 7, and 10. The calculations include a thermochemical model of the diffuse interstellar medium and treat dust and gas temperatures separately. We find that the stellar mass distributions obtained become increasingly bottom light as the redshift and/or metallicity are increased. Mass functions that are similar to a typical Galactic initial mass function are obtained for present-day star formation (z = 0) independent of metallicity, and also for the lowest-metallicity (1/100 solar) at all redshifts up to z = 10, but for higher metallicities there is a larger deficit of brown dwarfs and low-mass stars as the metallicity and redshift are increased. These effects are a result of metal-rich gas being unable to cool to as lower temperatures at higher redshift due to the warmer cosmic microwave background radiation. Based on the numerical results we provide a parameterisation that may be used to vary the stellar initial mass function with redshift and metallicity; this could be used in simulations of galaxy formation. For example, a bottom-light mass function reduces the mass-to-light ratio compared to a typical Galactic stellar initial mass function, which may reduce the estimated masses of high-redshift galaxies.

Analysis of the Efficacy of Different Obesity Surgeries in Patients with Metabolic Syndrome.

To investigate the effectiveness of different bariatric metabolic surgeries in improving metabolic syndrome indicators in patients. A retrospective analysis was conducted on obese patients who underwent laparoscopic sleeve gastrectomy (LSG), laparoscopic sleeve gastrectomy + jejunojejunal bypass (LSG + JJB), and laparoscopic Roux-en-Y gastric bypass (LRYGB). Patients were categorized into groups based on their surgical procedure: LSG (N = 199), LSG + JJB (N = 242), and LRYGB (N = 288). Successful laparoscopic bariatric metabolic surgery was achieved in 729 patients. Indicators related to body mass, glucose metabolism, insulin resistance, lipid metabolism, and kidney function showed significant improvement compared to the preoperative period. LSG, LSG + JJB, and LRYGB all demonstrate significant effectiveness in promoting weight loss and improving glycolipid metabolism in the short term. Post-surgery, symptoms of metabolic syndrome improved compared to the preoperative period, with LRYGB showing superior effectiveness over LSG + JJB and LSG.

Associations of nutritional intake and inflammatory factors with sarcopenia in community-dwelling older adults: a cross-sectional study.

Sarcopenia is an age-related disease that is related to nutritional intake and chronic low-grade inflammation. The aim of this study was to investigate the association of dietary intake, inflammatory markers and sarcopenia among the community-dwelling older adults. A total of 1001 older adults aged 60 and above were recruited. According to the criteria established by the Asian Working Group for Sarcopenia 2019, this paper assessed the presence of sarcopenia and using a Food Frequency Questionnaire to evaluate daily dietary intake. Serum levels of inflammatory markers were measured using the ELISA method. A total of 1001 participants took part in the study (mean 70.6years), comprising 396 males and 605 females, the prevalence of sarcopenia was 19.6%. Multivariate analysis revealed that high levels of leucine, methionine, threonine, histidine, aspartic acid, calcium, zinc, and vitamin C were associated with a lower risk of sarcopenia. Higher dietary inflammatory index scores were associated with a higher risk of sarcopenia (OR 1.67, 95% CI 1.12-2.47). Higher tumor necrosis factor-like weak inducer of apoptosis (TWEAK) (OR 1.04, 95% CI 1.02-1.07) was associated with a higher risk of sarcopenia, and a lower skeletal muscle mass, strength, and physical function. Conversely, higher insulin-like growth factor-1 (IGF-1) (OR 0.83, 95% CI 0.74-0.94) and glutathione S-transferase (GST) (OR 0.75, 95% CI 0.61-0.91) were associated with a lower risk of sarcopenia. This cross-sectional study revealed alterations in amino acid and micronutrient intake among older adults with sarcopenia. The levels of TWEAK were associated with an increased risk of sarcopenia, whereas IGF-1 and GST were associated with a reduced risk of sarcopenia.

Open cluster dissolution rate and the initial cluster mass function in the solar neighbourhood. Modelling the age and mass distributions of clusters observed by Gaia

Open cluster dissolution rate and the initial cluster mass function in the solar neighbourhood. Modelling the age and mass distributions of clusters observed by Gaia

Applying the Dempster–Shafer Fusion Theory to Combine Independent Land-Use Maps: A Case Study on the Mapping of Oil Palm Plantations in Sumatra, Indonesia

The remote sensing community benefits from new sensors and easier access to Earth Observation data to frequently released new land-cover maps. The propagation of such independent and heterogeneous products offers promising perspectives for various scientific domains and for the implementation and monitoring of land-use policies. Yet, it may also confuse the end-users when it comes to identifying the most appropriate product to address their requirements. Data fusion methods can help to combine competing and/or complementary maps in order to capitalize on their strengths while overcoming their limitations. We assessed the potential of the Dempster–Shafer Theory (DST) to enhance oil palm mapping in Sumatra (Indonesia) by combining four land-cover maps, hereafter named DESCALS, IIASA, XU, and MAPBIOMAS, according to the first author’s name or the research group that published it. The application of DST relied on four steps: (1) a discernment framework, (2) the assignment of mass functions, (3) the DST fusion rule, and (4) the DST decision rule. Our results showed that the DST decision map achieved significantly higher accuracy (Kappa = 0.78) than the most accurate input product (Kappa = 0.724). The best result was reached by considering the probabilities of pixels to belong to the OP class associated with DESCALS map. In addition, the belief (i.e., confidence) and conflict (i.e., uncertainty) maps produced by DST evidenced that industrial plantations were detected with higher confidence than smallholder plantations. Consequently, Kappa values computed locally were lower in areas dominated by smallholder plantations. Combining land-use products with DST contributes to producing state-of-the-art maps and continuous information for enhanced land-cover analysis.

Search for diphoton resonances in the 66 to 110 GeV mass range using pp collisions at s = 13 TeV with the ATLAS detector

A search is performed for light, spin-0 bosons decaying into two photons in the 66 to 110 GeV mass range, using 140 fb−1 of proton-proton collisions at s = 13 TeV produced by the Large Hadron Collider and collected by the ATLAS detector. Multivariate analysis techniques are used to define event categories that improve the sensitivity to new resonances beyond the Standard Model. A model-independent search for a generic spin-0 particle and a model-dependent search for an additional low-mass Higgs boson are performed in the diphoton invariant mass spectrum. No significant excess is observed in either search. Mass-dependent upper limits at the 95% confidence level are set in the model-independent scenario on the fiducial cross-section times branching ratio into two photons in the range of 8 fb to 53 fb. Similarly, in the model-dependent scenario upper limits are set on the total cross-section times branching ratio into two photons as a function of the Higgs boson mass in the range of 19 fb to 102 fb.

Star Cluster Population of High Mass Black Hole Mergers in Gravitational Wave Data

Stellar evolution theories predict a gap in the black hole birth mass spectrum as the result of pair instability processes in the cores of massive stars. This gap, however, is not seen in the binary black hole masses inferred from gravitational wave data. One explanation is that black holes form dynamically in dense star clusters where smaller black holes merge to form more massive black holes, populating the mass gap. We show that this model predicts a distribution of the effective and precessing spin parameters, χeff and χp, within the mass gap that is insensitive to assumptions about black hole natal spins and other astrophysical parameters. We analyze the distribution of χeff as a function of primary mass for the black hole binaries in the third gravitational wave transient catalog. We infer the presence of a high mass and isotropically spinning population of black holes that is consistent with hierarchical formation in dense star clusters and a pair-instability mass gap with a lower edge at 44−4+6M⊙. We compute a Bayes factor B>104 relative to models that do not allow for a high mass population with a distinct χeff distribution. Upcoming data will enable us to tightly constrain the hierarchical formation hypothesis and refine our understanding of binary black hole formation. Published by the American Physical Society 2025

JWST ERS Program Q3D: The pitfalls of virial black hole mass constraints shown for a z ∼ 3 quasar with an ultramassive host

We present observations with the Mid-InfraRed Instrument (MIRI) and Near-InfraRed Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST), targeting the extremely red quasar J165202.64+172852.3 at z = 2.948 (dubbed J1652). As one of the most luminous quasars known to date, it drives powerful outflows and hosts a clumpy starburst, in the midst of several interacting companions. We estimated the black hole (BH) mass of the system based on the broad Hα and Hβ lines, as well as the broad Paβ emission in the infrared and Mg II in the ultraviolet. We recovered a very broad range of mass estimates, with individual constraints ranging between log MBH ∼ 9 and 10.2, which is extended further if we impose a uniform broad line region geometry at all wavelengths. The large spread may be caused by several factors: uncertainties on measurements (insufficient sensitivity to detect the broadest component of the faint Paschen β line, spectral blending, ambiguities in the broad or narrow component distinction, etc.), lack of virial equilibrium, and uncertainties on the luminosity-inferred size of the broad line region (BLR). The exotic nature of our target (luminous, starburst, powerful outflows, high accretion rate, and dusty centre) is another likely contribution to the large uncertainties. We broadly constrained the stellar mass of J1652 by fitting the spectral energy distribution, which suggests that the host is extremely massive, at ∼1012.1 M⊙, with a 1.1 dex uncertainty at > 1 dex above the characteristic mass of the Schechter fit to the z = 3 stellar mass function. Notably, J1652’s central BH might be interpreted as being either over-massive or in line with the BH mass–stellar mass relation, depending on the choice of assumptions. The recovered Eddington ratio varies accordingly, but it exceeds 10% in any case. We set our results into context by providing an extensive overview and discussion of recent literature results and their associated assumptions. Our findings provide an important demonstration of the uncertainties inherent in the virial BH mass estimates of individual objects, which are of particular relevance in the JWST era, given the increasing number of studies on rapidly accreting quasars at high redshift.

A Probabilistic Model-Based Framework for Damage Detection in Beam-Like Structures Considering Temperature Effects

To improve the assessment outcomes of structural health monitoring systems, it has been acknowledged that the damage diagnostics process is associated with a considerable amount of uncertainties from operational and environmental sources such as temperature. This study presents a probabilistic framework for structural health monitoring aimed at identifying common defects such as cracks and corrosion in beam-like structures under varying temperature conditions. The framework utilizes optimization methods integrated with a probabilistic approach, comprising two levels of damage identification: first, determining the optimal probability mass function for the damage location ratio, followed by the optimal conditional for the damage depth ratio. A simply supported beam divided into four segments was modeled to evaluate the effectiveness of the proposed algorithm across various damage scenarios using frequency response signals. Structural damage was simulated by manipulating the length and depth ratios of specific beam segments. The modeling procedure for defects in the simply supported beam was validated through comparison with experimental measurements, achieving a maximum difference of less than 1%. The proposed algorithm consistently yielded improved damage detail outcomes in the second level, characterized by higher probabilities and lower uncertainties for both damage location and depth ratios. Identifying cracks and corrosion with a 0.1 depth ratio at low temperatures proved challenging, but the algorithm effectively addressed such scenarios, achieving identification probabilities exceeding 90%. The analysis outcomes demonstrate the advantages of the proposed framework for structural health monitoring that accounts for temperature effects, thereby improving the fidelity of damage assessment in real-world conditions.

Short-time collective dynamics of an ionic liquid: A computer simulation study with non-polarizable and polarizable models, and abinitio molecular dynamics.

Molecular dynamics (MD) simulation is used to study the intermolecular dynamics in the THz frequency range of the ionic liquid 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, [C2C1im][FSI]. Non-polarizable and polarizable models for classical MD simulation are compared using as quality criteria abinitio molecular dynamics (AIMD) and experimental data from far-infrared (FIR) spectroscopy and previously published data of inelastic x-ray scattering (IXS). According to data from IXS spectroscopy, incorporating polarization in the classical MD simulation has relatively little effect on the dispersion curve (excitation frequency vs wavevector) for longitudinal acoustic modes. When the AIMD simulation is used as a reference, the polarizable model leads the time correlation functions of velocity, mass, and charge currents to relax abnormally quickly. The charge current spectra from the AIMD simulation and the non-polarizable model agree with the experimental FIR spectrum, while the polarizable model gives an excessively broad band. When compared to the non-polarizable model, the polarizable model does improve the calculation of transport coefficients (diffusion coefficient, viscosity, and conductivity); however, it yields overdamped short-time collective dynamics.

TangoSIDM Project: Is the stellar mass Tully-Fisher relation consistent with SIDM?

Abstract Self-interacting dark matter (SIDM) has the potential to significantly influence galaxy formation in comparison to the cold, collisionless dark matter paradigm (CDM), resulting in observable effects. This study aims to elucidate this influence and to demonstrate that the stellar mass Tully-Fisher relation imposes robust constraints on the parameter space of velocity-dependent SIDM models. We present a new set of cosmological hydrodynamical simulations that include the SIDM scheme from the TangoSIDM project and the SWIFT-EAGLE galaxy formation model. Two cosmological simulations suites were generated: one (Reference model) which yields good agreement with the observed z = 0 galaxy stellar mass function, galaxy mass-size relation, and stellar-to-halo mass relation; and another (WeakStellarFB model) in which the stellar feedback is less efficient, particularly for Milky Way-like systems. Both galaxy formation models were simulated under four dark matter cosmologies: CDM, SIDM with two different velocity-dependent cross sections, and SIDM with a constant cross section. While SIDM does not modify global galaxy properties such as stellar masses and star formation rates, it does make the galaxies more extended. In Milky Way-like galaxies, where baryons dominate the central gravitational potential, SIDM thermalises, causing dark matter to accumulate in the central regions. This accumulation results in density profiles that are steeper than those produced in CDM from adiabatic contraction. The enhanced dark matter density in the central regions of galaxies causes a deviation in the slope of the Tully-Fisher relation, which significantly diverges from the observational data. In contrast, the Tully-Fisher relation derived from CDM models aligns well with observations.

EPOCHS. IV. SED Modeling Assumptions and Their Impact on the Stellar Mass Function at 6.5 ≤ z ≤ 13.5 Using PEARLS and Public JWST Observations

We utilize deep JWST Near Infrared Camera (NIRCam) observations for the first direct constraints on the Galaxy Stellar Mass Function (GSMF) at z > 10. Our EPOCHS v1 sample includes 1120 galaxy candidates at 6.5 < z < 13.5 taken from a consistent reduction and analysis of publicly available deep JWST NIRCam data covering the Prime Extragalactic Areas for Reionization Science, CEERS, GLASS, JADES GOOD-S, NGDEEP, and SMACS0723 surveys, totaling 187 arcmin2. We investigate the impact of spectral energy distribution fitting methods, assumed star formation histories (SFHs), dust laws, and priors on galaxy masses and the resultant GSMF. While our fiducial GSMF agrees with the literature at z < 13.5, we find that the assumed SFH model has a large impact on the GSMF and stellar mass density (SMD), finding a 0.75 dex increase in the SMD at z = 10.5 between a flexible nonparametric and standard parametric SFH. Overall, we find a flatter SMD evolution at z ≥ 9 than some studies predict, suggesting a rapid buildup of stellar mass in the early Universe. We find no incompatibility between our results and those of standard cosmological models, as suggested previously, although the most massive galaxies may require a high star formation efficiency. We find that the “little red dot” galaxies dominate the z = 7 GSMF at high masses, necessitating a better understanding of the relative contributions of active galactic nucleus and stellar emission. We show that assuming a theoretically motivated top-heavy initial mass function (IMF) reduces stellar mass by 0.5 dex without affecting fit quality, but our results remain consistent with existing cosmological models with a standard IMF.

Multiwavelength Constraints on the Local Black Hole Occupation Fraction

The fraction of dwarf galaxies hosting central, intermediate-mass black holes (IMBHs) at low redshifts is an important observational probe of black hole seeding at high redshift. Detections of nuclear accretion signatures in dwarf galaxies provides strong evidence for the presence of these IMBHs. We develop a Bayesian model to infer the black hole occupation fraction assuming a broken power-law Eddington ratio distribution function. Our approach accounts for nondetections, incompleteness, and contamination from star-forming-related emission. We apply this model to galaxies with X-ray data from the Chandra Source Catalog at distances <50 Mpc, radio data from the Very Large Array Sky Survey at <50 Mpc, and optical variability data from the Palomar Transient Factory at z < 0.055. We find a black hole occupation fraction of at least 90% at stellar masses of M ⋆ = 108 M ⊙ and at least 39% at M ⋆ = 107 M ⊙ (95% confidence intervals). We show the resulting black hole mass function. These constraints on the IMBH population have implications for the Laser Interferometer Space Antenna mission and for cosmological models of black hole seeding and growth. We also constrain the extremely low-luminosity end (L bol ≲ 1040 erg s−1) of the active galactic nucleus (AGN) luminosity functions at z = 0. Our AGN luminosity functions are broadly consistent with an extrapolation of the shallow slope of the AGN luminosity functions from previous work.

Exploring the association between pro-inflammatory mediators and sarcopenia in cancer patients through different diagnostic tools: a narrative review.

Sarcopenia, characterized by the progressive loss of skeletal muscle mass (MM) and muscle function, is a common and debilitating condition in cancer patients, significantly impacting their quality of life, treatment outcomes, and overall survival. The pathophysiology of sarcopenia is multifactorial, involving metabolic, hormonal, and inflammatory changes. Recent research highlights the role of chronic inflammation in the development and progression of sarcopenia, with pro-inflammatory cytokines being key mediators of muscle catabolism. The primary objective of this study was to assess the role of pro-inflammatory cytokines in identifying sarcopenia among cancer patients. As a secondary objective, we aim to investigate whether the methods used for assessing sarcopenia, both imaging and functional, align with established guidelines. A search of the Web of Science was conducted for English-language articles published since 2005, with the following terms: "Cancer" AND "Sarcopenia" AND "Pro-inflammatory cytokine*" OR "Interleukin*". Inclusion criteria included peer-reviewed controlled trials, observational studies, case reports, and case series. To avoid redundancy, articles with results which were included in systematic reviews, narrative reviews, or scoping reviews were excluded from this review. The analysis of 10 selected papers, including 1,138 cancer patients, revealed a lack of assessment of muscle strength (MS) and muscle functional performance in most of the studies on sarcopenia, contradicting the comprehensive nature of sarcopenia that includes MM, MS, and muscle functionality. There is no standardization of pro-inflammatory mediators for sarcopenia identification. Future research should focus on establishing cutoff points for inflammatory mediators and identifying which cytokines are linked to sarcopenia. Given the complexity of sarcopenia in different cancers, new projects should investigate whether cytokine expression depends on the tumor type. Moreover, considering that the majority of the study population comprised elderly individuals with primary sarcopenia, it is crucial to discern the extent to which the findings are influenced by age versus cancer-related factors.

Oral Frailty and Its Relationship with Physical Frailty in Older Adults: A Longitudinal Study Using the Oral Frailty Five-Item Checklist

Background/Objectives: Oral frailty, first identified in Japan in 2014, refers to a state between healthy oral function and severe decline, marked by minor issues, such as tooth loss and chewing difficulties. The oral frailty five-item checklist (OF-5) enables non-dental professionals to evaluate oral frailty using five key indicators: remaining teeth count, chewing difficulties, swallowing difficulties, dry mouth, and articulatory oral skills. Limited studies exist. Methods: This study examined the relationship between oral and physical frailties in older adults and assessed the prognosis of physical frailty using the OF-5. Participants aged ≥65 years were recruited from the frail elderly in the Sasayama–Tamba area, Hyogo, Japan, and their physical function was assessed in terms of grip strength, walking speed, and skeletal muscle mass. Blood markers, such as cystatin C, an indicator of renal function, were also analyzed. Results: A cross-sectional analysis indicated that oral frailty was correlated with reduced muscle mass, walking speed, and physical function. Women had lower hemoglobin and albumin levels and a greater prevalence of frailty than men. Longitudinal analysis revealed that initial OF-5 scores predicted increased physical frailty after 2–3 years, especially in those with higher baseline scores. The OF-5 was a significant factor for frailty progression in both sexes. Conclusions: These results suggest that early detection of oral frailty via the OF-5 may be useful in preventing the progression of overall frailty in older adults.

Periodic paralysis across the life course: age-related phenotype transition and sarcopenia overlap.

In Periodic Paralysis (PP), a rare inherited condition caused by mutation in skeletal muscle ion channels, the phenotype changes with age, transitioning from the episodic attacks of weakness that give the condition its name, to a more degenerative phenotype of permanent progressive weakness and myopathy. This leads to disability and reduced quality of life. Neither the cause of this phenotype transition, nor why it occurs around the age of 40 is known. However, 40 is also the age of onset of 'normal' age-related physiological decline when we consider (a) muscle mass and strength (b) physical function at the world class level and (c) age-related mitochondrial dysfunction. Elevated Na+, mitochondrial dysfunction and sarcoplasmic Ca2+ leak via the skeletal muscle ryanodine receptor (RyR1) have been implicated in both periodic paralysis myopathy and skeletal muscle ageing. We suggest this combination may trigger a negative spiral ultimately leading to progressive muscle failure. Understanding the interaction between ageing physiology and disease phenotype will provide a window into the healthy ageing process but also help understand how, and why PP phenotype changes with age. Understanding the mechanism underlying PP phenotype-transition and its link with ageing physiology, not only has the potential to identify the first disease modifying therapies for PP, but also to identify novel and potentially tractable mechanisms that contribute to sarcopenia, the pathological loss of muscle mass and function with age.