Mass Measurements Research Articles

The impact of sauna suits on body fluid loss, body temperature, and energy expenditure in athletes

This study aims to evaluate the impact of sauna suits compared with regular training clothing on body fluid loss, body temperature, and energy expenditure among elite athletes. A sample of 15 male university athletes from weight-class sports, such as Taekwondo and Wrestling, participated in the study. Using a counterbalanced measures design, participants were randomly assigned to wear sauna suits and regular training clothing in two separate sessions. Measurements of body mass, body temperature, and calorie expenditure were recorded pre- and post-exercise. The results demonstrated that sauna suits significantly increased body fluid loss, elevated body temperature, and enhanced calorie expenditure compared with regular training clothing. Specifically, the results indicated that body mass varied significantly by timing and clothing with a p-value of 0.001, body temperature also showed significant differences based on timing and clothing with a p-value of 0.001, and caloric expenditure differed by type of clothing with a p-value of 0.019. These findings suggest that sauna suits are effective tools for rapid weight reduction and performance enhancement in weight-class sports, though caution is advised to mitigate risks of dehydration and overheating. Future research should investigate the long-term effects and safety of sauna suit use.

Observations of Microlensed Images with Dual-field Interferometry: On-sky Demonstration and Prospects

Abstract Interferometric observations of gravitational microlensing events offer an opportunity for precise, efficient, and direct mass and distance measurements of lensing objects, especially those of isolated neutron stars and black holes. However, such observations have previously been possible for only a handful of extremely bright events. The recent development of a dual-field interferometer, GRAVITY Wide, has made it possible to reach out to significantly fainter objects and increase the pool of microlensing events amenable to interferometric observations by 2 orders of magnitude. Here, we present the first successful observation of a microlensing event with GRAVITY Wide and the resolution of microlensed images in the event OGLE-2023-BLG-0061/KMT-2023-BLG-0496. We measure the angular Einstein radius of the lens with subpercent precision, θ E = 1.280 ± 0.009 mas. Combined with the microlensing parallax detected from the event light curve, the mass and distance to the lens are found to be 0.472 ± 0.012 M ⊙ and 1.81 ± 0.05 kpc, respectively. We present the procedure for the selection of targets for interferometric observations and discuss possible systematic effects affecting GRAVITY Wide data. This detection demonstrates the capabilities of the new instrument, and it opens up completely new possibilities for the follow-up of microlensing events and future routine discoveries of isolated neutron stars and black holes.

Dust characterization of protoplanetary disks: A guide to multi-wavelength analyses and accurate dust mass measurements

Dust characterization of protoplanetary disks: A guide to multi-wavelength analyses and accurate dust mass measurements

Model for the curvature response of the CDF II drift chamber

The CDF II experiment at the Fermilab Tevatron used a drift chamber to measure the momenta of charged particles. We present a model for the response of the drift chamber to the curvature of a charged particle's trajectory. Constraints on the model parameters are obtained from cosmic-ray data and from information published by CDF in the context of the W boson mass measurement. Implications for the calibration of the drift chamber measurement of momentum are discussed. The robustness of the CDF calibration procedure is demonstrated. The model provides a framework for the analysis of precision magnetic trackers of high-momentum particles. Published by the American Physical Society 2025

On-Site Implementation of External Wrench Measurement via Non-Linear Optimization in Six-Axis Force–Torque Sensor Calibration and Crosstalk Compensation

This study introduces a novel calibration method for accurate external wrench measurement using a six-axis FT (force–torque) sensor. We propose a sensor model and calibration method for FT sensors that enable precise separation of the force and torque components without the need for additional devices or sensors by estimating essential parameters: bias, crosstalk, CoM (center of mass), and inclination. By directly utilizing manufacturer-provided data, our approach eliminates the complexities of traditional calibration processes while achieving higher accuracy in force–torque measurements. This method simplifies the calibration workflow and enhances the practicality of FT sensor applications. A mobile manipulator installed with an FT sensor and a gripper is used to demonstrate calibration effectiveness across varying postures and incline conditions, with non-linear optimization based on the gradient descent method applied to minimize sensor-data errors. The tilt of the base is implemented by placing a step under the wheels of the mobile base to simulate roll or pitch scenarios. A digital level was used to measure the angle and verify that our predicted results were accurate. The proposed method addresses typical calibration challenges, including the effects of the end tool and base incline, which are not commonly covered in existing methods. The results show that, on a non-inclined base, crosstalk and CoM calibration reduces the MSE (mean squared error) by 55.8%, 56.2%, and 14.5% for the external force with respect to data without any calibration conducted. On an inclined base, our full calibration process reduces the MSE by a maximum of 98.6% for external mass measurement with respect to no calibration method applied. These findings highlight the importance of incline calibration for achieving accurate external force estimations, especially in mobile manipulator applications where the environment frequently changes.

Electrochemical impedance spectroscopy as a micropropagation monitoring tool for plants: A case study of tamarillo Solanum betaceum callus.

Tamarillo is an economically important species that has been extensively studied in terms of invitro morphogenesis and micropropagation techniques, including somatic embryogenesis. Callus cultures are used to characterize plant growth and differentiation as well as the production of secondary metabolites. In all cases, real-time screening methods to characterize cellular growth remain poorly explored. Here, we show that electrochemical impedance spectroscopy (EIS) enables non-invasive and real-time monitoring of callus growth and cytological changes. A non-embryogenic callus line derived from leaf explants of tamarillo was used. The callus was tested in both standard culture medium containing the auxin picloram and in auxin-free medium. The low frequency impedance modulus and the equivalent circuit charge transfer resistance are found to effectively translate real-time cellular growth and microstructural deformations which have been benchmarked with light and scanning electron microscopy and mass measurements. EIS therefore emerges as a micropropagation monitoring technique in plant biotechnology.

Precise Measurement of the Cosmic-Ray Spectrum and 〈ln A〉 by LHAASO: Connecting the Galactic to the Extragalactic Components

Abstract Recently, the LHAASO Collaboration has provided precise measurements of the cosmic rays (CRs) all-particle energy spectrum and mean logarithmic mass ln A from 0.3 to 30 PeV. Combining the CR measurements by AMS-02 and DAMPE in space and those by LHAASO and Auger on the ground, we construct a model to recover all these measurements from tens of GeV to tens of EeV. We find that the LHAASO measurement is crucial in the model construction by connecting the Galactic component to the extragalactic component. The precise measurements of CR spectra for individual species by AMS-02 and DAMPE together with the newest LHAASO results clearly indicate three Galactic CR components, that is, a soft low-energy background, a hard high-energy component, and a local source contribution. However, the LHAASO data show that above ∼1016 eV, a nonnegligible extra component, possibly of extragalactic origin, must be included. Combining the Auger results and the LHAASO results, we figure out the extragalactic CRs that need at least two components at lower and higher energies. Thanks to the measurements by LHAASO, the constraints on the model parameters are quite stringent. The spectrum features and mass measurements in all energy ranges are all well reproduced in the model.

Validation of a fully automated AI system for accurate left ventricular mass measurement in echocardiography

Abstract Background Accurate measurement of left ventricular mass (LVM) with 2D transthoracic echocardiography (Echo) provides prognostic information, and aids in tailoring treatment plans. Purpose We sought to validate a fully automated artificial intelligence (AI) system for LVM measurement in Echo against human measurements and computed tomography (CT), considered the gold standard. Methods 101 patients with symptomatic aortic valve stenosis (AS), 48 with mitral valve regurgitation (MR), and 41 with tricuspid valve regurgitation (TR) underwent both Echo and cardiac spiral CT on the same day, the latter for planning interventional valve repair. End-diastolic septal and posterior wall thickness (IVSD, PW), along with end-diastolic diameter (EDD) from LV parasternal long axis views in Echo, were independently measured for 1-dimensional LVM calculation by both an AI and an experienced cardiologist (>10 years) (Figure 1A). Notably, the AI performed fully automated view selection from the entire Echo exam and measured LV diameter and wall thickness on appropriate LV views without operator involvement. LVM results from CT were supervised by an experienced radiologist (>10 years) (Figure 1B). Pearson’s correlation coefficient (r), regression analysis, and mean absolute error (MAE) were used to assess agreement of measurement values between methods. Results The final cohort consisted of 164 patients, with complete LVM calculations by AI, human, and CT (feasibility: 91%, 95%, and 99%, respectively). LVM from AI and human correlated strongly (r=0.83, MAE=22 g), but AI exhibited higher agreement with CT (r=0.69, MAE=28 g) than human LVM measurement (r=0.62, MAE=37 g) (Figures 1C and 1D). AI and human measurements showed good correlation for IVSD (r=0.74, MAE=0.18 cm) and EDD (r=0.73, MAE=0.54 cm), but low correlation for PWD (r=0.48, MAE=0.23 cm). Conclusion The findings highlight the potential use of an AI-based application for fully automated view selection and measurement of LV wall thickness and diameter, demonstrating strong agreement of LV mass with CT and human measurements.

Effects of Planetary Mass Uncertainties on the Interpretation of the Reflectance Spectra of Earth-like Exoplanets

Abstract Atmospheric characterization of Earth-like exoplanets through reflected light spectroscopy is a key goal for upcoming direct imaging missions. A critical challenge in this endeavor is the accurate determination of planetary mass, which may influence the measurement of atmospheric compositions and the identification of potential biosignatures. In this study, we used the Bayesian retrieval framework EXOREL ℜ to investigate the impact of planetary mass uncertainties on the atmospheric characterization of terrestrial exoplanets observed in reflected light. Our results indicate that precise prior knowledge of the planetary mass can be crucial for accurate atmospheric retrievals if clouds are present in the atmosphere. When the planetary mass is known within 10% uncertainty, our retrievals successfully identified the background atmospheric gas and accurately constrained atmospheric parameters together with clouds. However, with less constrained or unknown planetary mass, we observed significant biases, particularly in the misidentification of the dominant atmospheric gas. For instance, the dominant gas was incorrectly identified as oxygen for a modern Earthlike planet or carbon dioxide for an Archean Earth–like planet, potentially leading to erroneous assessments of planetary habitability and biosignatures. These biases arise because the uncertainties in planetary mass affect the determination of surface gravity and atmospheric scale height, leading the retrieval algorithm to compensate by adjusting the atmospheric composition. Our findings emphasize the importance of achieving precise mass measurements—ideally within 10% uncertainty—through methods such as extreme precision radial velocity or astrometry, especially for future missions like the Habitable Worlds Observatory.

Update over de diagnose en behandeling van postmenopauzale osteoporose

Update on the diagnosis and treatment of postmenopausal osteoporosis Osteoporosis is characterized by a low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in spontaneous or low-impact fractures. These fractures are associated with a significant impact on morbidity and mortality. This article provides a literature overview of the most recent guidelines of the Belgian Bone Club with regard to screening, diagnosis, treatment and follow-up of postmenopausal osteoporosis. The Belgian Bone Club recommends screening for osteoporosis in all women ≥ 50 years, or at the age of menopause if this occurs earlier. After a positive screening, the guidelines recommend an evaluation of previous fragility fractures, a measurement of bone mass by DXA and a calculation of the fracture risk with computer-based algorithms. Based on these three criteria, we categorize the fracture risk as low, high or very high. Lifestyle measures and sufficient calcium and vitamin D intake are recommended in all categories. Antiresorptive treatment should be considered for high-risk patients (selective estrogen receptor modulators, bisphosphonates or the anti-RANK antibody denosumab). For patients at very high-risk, anabolic therapy, such as teriparatide or romosozumab, is preferred. All anabolic therapy should be followed by antiresorptive therapy. It is recommended to regularly monitor the effectiveness and tolerance of therapy, including a DXA measurement every 2 to 5 years.

Oscillating microbubbly flows generated by a fluidic oscillator: Flow behavior and mass transfer characteristics

AbstractIn this study, a Coanda‐swept fluidic oscillator is used to generate oscillating microbubbly flows. Flow behavior measurements show that the generated microbubbly flows have periodic sweep characteristics. Massive microbubbles are generated by shear‐off‐induced breakup, dynamic erosion breakup, and wall‐fluid‐shear‐induced breakup within the fluidic oscillator. Mass transfer measurements show that the generated microbubbly flows have a higher interfacial area (a) and volumetric liquid‐side mass transfer coefficients (kL) than the other comparison groups. Furthermore, the energy efficiency is assessed in terms of kL per energy consumption (η) and energy consumption per a (ξ). For the fluidic oscillator group, the highest kLa is 0.089 s−1, corresponding to (η = 0.63 m3/(kW·s), ξ = 2.6 J/m2, a = 785 m2/m3). Although it has been reported that higher kLa is typically associated with lower energy efficiency, the results indicate that the fluidic oscillator is a promising microbubble generator.

Detecting kHz gravitons from a neutron star merger with a multi-mode resonant mass detector

Abstract We propose a multi-mode bar consisting of mass elements of decreasing size for the implementation of a gravitational version of the photo-electric effect through the stimulated absorption of up to kHz gravitons from a binary neutron star merger and post-merger. We find that the multi-mode detector has normal modes that retain the coupling strength to the gravitational wave of the largest mass-element, while only having an effective mass comparable to the mass of the smallest element. This allows the normal modes to have graviton absorption rates due to the tonne-scale largest mass, while the single graviton absorption process in the normal mode could be resolved through energy measurements of a mass-element in-principle smaller than pico-gram scale. We argue the feasibility of directly counting gravito-phonons in the bar through energy measurements of the end mass. This improves the transduction of the single-graviton signal, enhancing the feasibility of detecting single gravitons.

Radial-dependent Responsivity of Broad-line Regions in Active Galactic Nuclei: Observational Consequences for Reverberation Mapping and Black Hole Mass Measurements

Abstract The reverberation mapping (RM) technique has seen wide applications in probing geometry and kinematics of broad-line regions (BLRs) and measuring masses of supermassive black holes (SMBHs) in active galactic nuclei. However, key quantities in RM analysis such as emissivity, responsivity, transfer functions, and mean and rms spectra are fragmentally defined in the literature and largely lack a unified formulation. Here we establish a rigorous framework for BLR RM and include a locally dependent responsivity according to photoionization calculations. The mean and rms spectra are analytically expressed with emissivity- and responsivity-weighted transfer functions, respectively. We demonstrate that the rms spectrum is proportional to the responsivity-weighted transfer function only when the continuum variation timescale is much longer than the typical extension in time delay of the BLR; otherwise, biases arise in the obtained rms line widths. The long-standing phenomenon pertaining to the different shapes between the mean and rms spectra can be explained by a radial-increasing responsivity of BLRs. The debate on the choice of emission-line widths for SMBH mass measurements is explored, and the virial factors are suggested to also depend on the luminosity states, in addition to the geometry and kinematics of BLRs.

P0271 Overweight is associated with low mediterranean diet adherence and increased disability in patients with Inflammatory Bowel Disease

Abstract Background The prevalence of obesity in inflammatory bowel disease (IBD) has risen, with 15–40% of adults classified as obese and an additional 20–40% as overweight1. Poor dietary habits and sedentary lifestyles contribute to overweight and sarcopenia, potentially worsening IBD-related disability. This study aimed to evaluate the relationships between nutritional status, adherence to the Mediterranean diet, sarcopenia and disability in IBD patients. Methods This cross-sectional study included consecutive IBD patients attending an outpatient clinic or infusion unit between 2023-2024. Bioelectrical impedance analysis (BIA) was used to estimate the fat-free mass index (FFMI), a recognized measure of skeletal muscle mass. Physical function was assessed via gait speed (time to walk 6 meters), and handgrip strength (HGS) measured using a Jamar dynamometer. Sarcopenia was diagnosed based on FFMI, HGS, and walking speed. Disability was evaluated using the IBD-Disk questionnaire, with scores ≥40 indicating moderate-to-severe disability. Adherence to the Mediterranean diet was assessed using the Medi-Lite score, with scores <9 reflecting low adherence. Demographic, clinical, and disease-related data were collected Results A total of 95 IBD patients (58% with Crohn’s disease, CD), 57.8% female, with a median age of 42 years (IQR 26-58) were included. Clinical activity ,measured with the Harvey-Bradshaw index (HBI) had a median score of 6 (IQR 4–7) for CD, while the median pMayo score for ulcerative colitis (UC) was 4 (IQR 2–6). The median BMI was 23.60 (IQR 21-27). Overweight prevalence was 43.2% (41/95). Low adherence to the Mediterranean diet was significantly more frequent in overweight patients compared to non-overweight patients (p<0.001). Overweight was also associated with increased age (p < 0.001). Sarcopenia prevalence was 7% (7/95) and was more common in non-overweight patients than in overweight patients (p = 0.002). The median BMI among sarcopenic patients was 20.6 (18.5–25.3). The mean IBD-Disk score was 41 ± 23.2, with 46.3% of patients reporting moderate-to-severe disability. Overweight patients were more likely to experience moderate-to-severe disability compared to non-overweight patients [27 (65.9%) vs. 23 (42.6%), p = 0.02]. No significant association was found between sarcopenia and moderate-to-severe disability (p = 0.44). Conclusion Overweight is associated with low adherence to the Mediterranean diet and increased disability in IBD patients. Targeted interventions to improve adherence to the Mediterranean diet and manage overweight could potentially reduce disability in IBD patients.

Precise interpretations of traditional fine-tuning measures

We uncover two precise interpretations of traditional electroweak fine-tuning (FT) measures that were historically missed. : the traditional FT measure shows the change in plausibility of a model in which a parameter was exchanged for the Z boson mass relative to an untuned model in light of the Z boson mass measurement. the traditional FT measure shows the exponential of the extra information, measured in nats, relative to an untuned model that you must supply about a parameter in order to fit the Z mass. We derive the mathematical results underlying these interpretations, and explain them using examples from weak scale supersymmetry. These new interpretations allow us to rigorously define FT in particle physics and beyond, shed fresh light on the status of extensions to the Standard Model and, lastly, allow us to precisely reinterpret historical and recent studies using traditional FT measures. Published by the American Physical Society 2025

Age- and sex-adjusted CT-based reference values for temporal muscle thickness, cross-sectional area and radiodensity

Muscle mass has been traditionally assessed by measuring paraspinal muscle areas at the level of the third lumbar vertebra on computed tomography (CT). Neurological or neurosurgical patients seldom undergo CT scans of the lumbar region. Instead, temporal muscle thickness (TMT), cross-sectional area (TMA) and radiodensity measured from head CT scans are readily available measures of muscle mass and quality in these patient cohorts. The purpose of this retrospective study was to establish CT-based reference values for TMT, TMA and radiodensity for each decade of age from 0 to 100 years normalized by age and sex, and to define cut-off values for subjects at risk for sarcopenia as defined by the European Working Group on Sarcopenia in Older People (EWGSOP). Subjects diagnosed with a concussion at the Oulu University Hospital between January 2014 and December 2022 (n = 9254) were identified to obtain a reference population. Subjects with significant pre-existing co-morbidities were excluded. TMT, TMA and radiodensity were measured, measurement reliability was quantified, and sex-adjusted reference values were calculated for each age decade. Quantile regression was used to model age-related changes in muscle morphomics. A total of 500 subjects [250 (50.0%) males] with a mean age of 49.2 ± 27.9 years were evaluated. Inter- and intra-observer reliability was almost perfect for TMT and TMA, and substantial-to-almost perfect for radiodensity. The mean TMT, TMA and radiodensity were 5.2 ± 1.9 mm, 284 ± 159 mm2 and 44.6 ± 17.7HU, respectively. The cut-off values for reduced TMT, TMA and radiodensity for males/females using the European Working Group on Sarcopenia in Older People compliant criteria were ≤ 4.09 mm/≤3.44 mm, ≤ 166 mm2/≤156 mm2, and ≤ 35.5HU/≤35.2HU, respectively. We described a standardized CT-based TMT and TMA measurement protocol practical for clinical use with almost perfect reliability. Using the protocol, we produced quantile regression models for the detection of reduced TMT, TMA and radiodensity at the lowest 5th, 10th, 20th, 30th, 40th and 50th percentiles as well as the EWGSOP compliant criteria cut-off values for reduced muscle mass to facilitate generalizable radiological sarcopenia research.

Associations between skeletal muscle mass and elevated blood pressure are independent of body fat: a cross-sectional study in young adult women of African ancestry.

Although research on the relationship between lean body mass and blood pressure (BP) has been inconsistent, most studies reported that measures of lean body mass are associated with a higher risk of hypertension. We explored relationships between body composition (fat and skeletal muscle mass) and BP in 1162 young adult African women. DXA-derived measures of whole body, central and arm fat mass were associated with higher systolic and diastolic BP, while leg fat percentage was associated with lower systolic and diastolic BP. However, only the associations with diastolic BP remained after adjusting for appendicular skeletal muscle mass (ASM). ASM was associated with higher systolic and diastolic BP, before and after adjusting for whole-body fat percentage and VAT.While there was no overlap in targeted proteomics of BP and body composition, REN was lower in the elevated BP than the normal BP group and was inversely associated with diastolic BP (false-rate discovery adjusted p<0.050). Several proteins were positively associated with both VAT and ASM (LEP, FABP4, IL6, and GGH) and negatively associated with both VAT and ASM (ACAN, CELA3A, PLA2G1B, and NCAM1). NOTCH3, ART3, COL1A1, DKK3, ENG, NPTXR, AMY2B, and CNTN1 were associated with lower VAT only, and IGFBP1 was associated with lower ASM only.While the associations between body fat and BP were not independent of skeletal muscle mass, the associations between muscle mass and BP were independent of overall and central adiposity in young adult African women. Future interventions targeting muscle mass should also monitor BP in this population.

The Effects of Glucagon-Like Peptide-1 Receptor Agonists on Mitochondrial Function Within Skeletal Muscle: A Systematic Review.

Obesity is a chronic disease associated with increased risk of multiple metabolic and mental health-related comorbidities. Recent advances in obesity pharmacotherapy, particularly with glucagon-like peptide-1 (GLP-1) receptor agonists (RAs), have the potential to transform obesity and type 2 diabetes mellitus (T2DM) care by promoting marked weight loss, improving glycaemic control and addressing multiple obesity-related comorbidities, with added cardio-renal benefits. Dual agonists combining GLP-1 with other enteropancreatic hormones such as glucose-dependent insulinotropic polypeptide (GIP) have also been developed in recent years, leading to greater weight loss than using GLP-1 RAs alone. However, up to 40% of the weight lost with GLP-1 RAs comes from lean body mass, raising concerns about potential adverse effects on skeletal muscle function. Mitochondrial dysfunction, characterized by reduced mitochondrial size and activity, is prevalent in individuals with obesity and T2DM and is a known contributor to muscle wasting in ageing and some chronic diseases. This systematic review investigates the impact of GLP-1-based therapies on skeletal muscle mitochondrial function in individuals with obesity and T2DM or in related animal and cell models. A comprehensive search of MEDLINE, Scopus, CINAHL and clinicaltrials.gov was conducted. Inclusion criteria included randomized controlled trials, randomized crossover trials, cluster randomized control trials and basic science studies involving any GLP-1 RA or GLP-1/GIP dual agonist. Outcomes of interest were skeletal muscle respiratory function either in the form of measurements of mass, number, content, oxidative capacity/respiratory function, mitochondrial dynamics, mitochondrial biogenesis and mitophagy. Eight studies were eligible for analysis; no human studies were identified. All of the included studies used GLP-1 RAs (single agonists) as intervention. The emerging evidence suggests that GLP-1 RAs increase mitochondrial area, number and morphology (i.e., reduces swelling). Data are conflicting on the effect of GLP-1 RAs upon mitochondrial mass, respiration and the expression of uncoupling proteins and PGC-1α. Data also demonstrate muscle specific (i.e., soleus vs. extensor digitorum longus) responses to GLP-1 RAs. GLP-1 RAs appear to have a positive effect upon mitochondria area, number and morphology, but effects upon other aspects of mitochondrial health remain inconclusive. Data are very limited and solely presented in animal and invitro models. Future studies should be conducted in human populations in order to begin to understand the effect of GLP-1 RAs and GLP-1-based therapies on human skeletal muscle mitochondria.

Characterization of Ultraviolet-Degraded Polyethylene Terephthalate Film Using a Complementary Approach: Reactive Pyrolysis–Gas Chromatography–Mass Spectrometry and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

Polyethylene terephthalate (PET) is widely used across various industries owing to its versatility and favorable properties, including application in beverage bottles, food containers, textile fibers, engineering resins, films, and sheets. However, polymer materials are susceptible to degradation from factors such as light, oxygen, and heat. Therefore, it is crucial to understand the structural changes that occur during degradation and the extent of these changes. This report investigates the structural alterations in PET films resulting from ultraviolet (UV) irradiation utilizing pyrolysis-gas chromatography time-of-flight mass spectrometry (Py-GC-TOFMS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOFMS). Using the reactive Py-GC-TOFMS, we estimated the composition of the pyrolysis products resulting from UV degradation through electron ionization, soft ionization, and exact mass measurements. Additionally, artificial intelligence (AI)-based structure analysis was performed to evaluate these compounds' structures. Notably, most degradation products were not found in the National Institute of Standards and Technology database, underscoring the effectiveness of our approach. Using MALDI-TOFMS analysis, we determine the changes in the end groups before and after UV irradiation. This analysis confirmed the generation of a series of carboxylic acid end groups as a result of degradation, a polymer series not detected by reactive pyrolysis GC-MS. We also explored degradation in the depth direction, demonstrating that degradation progresses gradually to depths of several micrometers. Our findings highlight the importance of employing mass spectrometry techniques for a comprehensive analysis of polymer degradation.

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.