Absolute Mass Research Articles

Dynamic analysis on an asymmetric spatial dumbbell-type model

The structural symmetric breaking of the spatial structure will enhance the coupling dynamic behaviors and bring new challenges for the dynamic analysis on the spatial structure inevitably. The main contribution of this paper is proposing a structure-preserving iteration method to investigate the effects of the dynamic symmetry-breaking factors on the dynamic behaviors of the rigid-flexible coupling systems. Firstly, the spatial flexible damping beam assembled with two particles on both ends is simplified as an asymmetric spatial dumbbell-type model. For this model, the coupling dynamic equations are presented based on the Hamiltonian variational principle. Then, connecting the symplectic precise integration method for the ordinary differential equations mainly controlling the plane motion of the model and the generalized multi-symplectic scheme for the partial differential equation mainly controlling the transverse vibration of the beam, a structure-preserving numerical iteration method is proposed, which provides a new way to analysis the dynamic behaviors of the coupling problems with the symmetric breaking. Finally, the effects of the absolute mass and the mass ratio of the additional particles on the orbit radius, the orbit true anomaly velocity, the attitude angle velocity of the model and the transverse vibration of the flexible beam are reproduced by using the structure-preserving numerical iteration method in the numerical simulations. Particularly, the effects of the additional particles on the attitude stability of the model and the vibration dissipation of the flexible damping beam are investigated, which gives some guidance for the attitude adjustment strategy and the vibration control method for the spatial flexible structure with the structural symmetric breaking.

Survey of neutrino flavor predictions and the neutrinoless double beta decay funnel

The neutrinoless double beta decay experimental effort continues to make tremendous progress with hopes of covering the inverted neutrino mass hierarchy in coming years and pushing from the quasidegenerate hierarchy into the normal hierarchy. As neutrino oscillation data are starting to suggest that the mass ordering may be normal, we may well be faced with staring down the funnel of death: a region of parameter space in the normal ordering where—for a particular cancellation among the absolute neutrino mass scale, the Majorana phases, and the oscillation parameters—the neutrinoless double beta decay rate may be vanishingly small. To answer the question of whether this region of parameter space is theoretically preferred, we survey five broad categories of flavor model structures which make various different predictions for parameters relevant for neutrinoless double beta decay to determine how likely it is that the rate may be in this funnel region. We find that a non-negligible fraction of predictions surveyed are at least partially in the funnel region. Our results can guide model builders and experimentalists alike in focusing their efforts on theoretically motivated regions of parameter space. Published by the American Physical Society 2024

Comparative analysis on the validity of golden ratio, tri-bimaximal, hexagonal and bimaximal neutrino mixing patterns under the radiative corrections

We study the comparative analysis on the validity of four popular leptonic mixing patterns viz, golden ratio (GR), tri-bimaximal (TBM), hexagonal mixing (HM) and bimaximal (BM), which are assumed to be defined at high energy scale, M R = 1016 GeV. We perform numerical analysis of low energy neutrino oscillation parameters through the renormalisation group equations (RGEs) in both standard model (SM) and minimal supersymmetric standard model (MSSM) with the inclusion of scale dependent vacuum expectation value (VEV). The sum of three absolute neutrino mass eigenvalues obtained from the latest Planck cosmological data, ∑∣m i ∣ < 0.12 eV, is used as a constraint in the analysis of these four leptonic mixing patterns. We consider both normal hierarchical (NH) model and inverted hierarchical (IH) model in the analysis of these four leptonic mixing patterns, with SUSY breaking scale at m s = 1 TeV and tanβ=67 . Among the four mixing patterns, GR is found to satisfy the latest Planck cosmological data, ∑∣m i ∣ < 0.12 eV. Further analysis on the effect of the variation of SUSY breaking scale 1 TeV ≤ m s ≤ 14 TeV is also studied for GR neutrino mixing pattern in NH.

Tracking Body Composition Over a Competitive Season in Elite Soccer Players Using Laboratory- and Field-Based Assessment Methods.

Bongiovanni, T, Lacome, M, Rodriguez, C, and Tinsley, GM. Tracking body composition over a competitive season in elite soccer players using laboratory- and field-based assessment methods. J Strength Cond Res 38(3): e104-e115, 2024-The purpose of this study was to describe body composition changes in professional soccer players over the course of a competitive playing season and compare the ability of different assessment methods to detect changes. Twenty-one elite male soccer players (age: 23.7 ± 4.8 years; height: 185.0 ± 5.2 cm; body mass: 80.7 ± 5.5 kg; body fat: 12.8 ± 2.2%) playing for an Italian national second league (Serie B) championship team were assessed at 4 time points throughout a competitive season: T0 (mid-October), T1 (mid-December), T2 (mid-February), and T3 (end of April). Dual-energy x-ray absorptiometry (DXA), skinfolds (SKF), and bioelectrical impedance analysis were performed at each time point, and multiple SKF-based equations were applied. A modified 4-compartment (4C) model was also produced. Data were analyzed using repeated measures analysis of variance, relevant post hoc tests, and Pearson's correlations. Dual-energy x-ray absorptiometry, 4C, and the SKF-based equations of Reilly and Civar detected differences in fat-free mass (FFM) between time points, with the most differences observed for DXA. Fat-free mass increased from T0 values to a peak at T2, followed by a decrease by T3, although FFM values remained higher than T0. Fat-free mass gain was primarily driven by increases in the lower limbs. Fat-free mass changes between all methods were significantly correlated, with correlation coefficients of 0.70-0.97. No significant differences between time points were observed for absolute fat mass or body fat percentage, although significant correlations between several methods for change values were observed. Select laboratory and field methods can detect changes in FFM over the course of a season in elite, professional soccer athletes, with a more limited ability to detect changes in adiposity-related variables. For SKF in this population, the equation of Reilly is recommended.

Neutrino mass and nature through its mediation in atomic clock interference

The absolute mass of neutrinos and their nature are presently unknown. Aggregate matter has a coherent weak charge leading to a repulsive interaction mediated by a neutrino pair. The virtual neutrinos are non-relativistic at micron distances, giving a distinct behavior for Dirac versus Majorana mass terms. This effective potential allows for the disentanglement of the Dirac or Majorana nature of the neutrino via magnitude and distance dependence. We propose an experiment to search for this potential based on the concept that the density-dependent interaction of an atomic probe with a material source in one arm of an atomic clock interferometer generates a differential phase. The appropriate geometry of the device is selected using the saturation of the weak potential as a guide. The proposed experiment has the added benefit of being sensitive to gravity at micron distances. A strategy to suppress the competing Casimir–Polder interaction, depending on the electronic structure of the material source, as well as a way to compensate the gravitational interaction in the two arms of the interferometer is discussed.

The effect of chronic habitual exercise on oxygen carrying capacity and blood compartment volumes in older adults.

Absolute total hemoglobin mass (tHbmass) and blood compartment volumes are often considered to be higher in endurance athletes compared with nonathletes, yet little data support a fitness effect in older age. Therefore, we measured tHbmass and blood compartment volumes (carbon monoxide rebreathing) in 77 healthy individuals (23% female; aged, 60-87 yr). Participants were recruited into groups based upon their lifelong (>25 yr) exercise "dose": 1) 15 sedentary individuals, <2 sessions/wk; 2) 25 casual exercisers, 2-3 sessions/wk; 3) 24 committed exercisers, 4-5 sessions/wk; and 4) 13 competitive Masters athletes, 6-7 sessions/wk, plus regular competitions. Absolute (L/min) and relative (mL/kg/min) V̇o2peak were higher with increasing exercise "dose" (P = 0.0005 and P < 0.0001, respectively). Hemoglobin concentration, hematocrit, and absolute tHbmass and blood compartment volumes were not significantly different between groups (all, P > 0.1328). When scaled to body mass, tHbmass (Sedentary, 9.2 ± 1.7 mL/kg; Casual, 9.2 ± 1.3; Committed, 10.2 ± 1.4; Competitive, 11.5 ± 1.4, ANOVA P < 0.0001) and blood volume were significantly different between groups [Sedentary, 63.4 (59.2-68.5) mL/kg; Casual, 67.3 (64.4-72.6); Committed, 73.5 (67.5-80.2); Competitive, 83.4 (78.9-88.6), ANOVA P < 0.0001], whereby all values were highest in Masters athletes. However, when scaled to fat-free mass (FFM), tHbmass and blood compartment volumes were greater in Competitive compared with Casual exercisers (all, P < 0.0340) and tHbmass and erythrocyte volume were also higher in Committed compared with Casual exercisers (both, P < 0.0134). In conclusion, absolute tHbmass and blood compartment volumes are not different between groups, with dose-dependent differences only among exercisers when scaled for FFM, with the highest tHbmass and blood compartment volumes in competitive Masters athletes.NEW & NOTEWORTHY We observed that absolute oxygen carrying capacity (total hemoglobin mass, tHbmass) and blood compartment volumes were not associated with lifelong exercise dose. However, hematological adaptations associated with lifelong habitual exercise are only present among exercisers, whereby competitive Masters athletes have a greater oxygen carrying capacity (tHbmass) and expanded blood compartment volumes when scaled to fat-free mass.

Preconception Micronutrient Supplementation Affects Maternal BMI and Body Composition Postpartum: A Randomized Controlled Trial in Vietnam

BackgroundAlthough there is growing evidence on the role of preconception nutrition for birth outcomes, limited evidence exists for its effects on maternal health. ObjectivesThis study evaluates the impact of preconception micronutrient supplementation on maternal BMI (kg/m2) and body composition at 6 to 7 y postpartum (PP). MethodsWe followed females who participated in a randomized controlled trial of preconception supplementation in Vietnam and delivered live offspring (n = 1599). Females received weekly supplements containing either 2800 μg folic acid (FA) only, 60 mg iron and 2800 μg FA (IFA), or multiple micronutrients (MMs) (15 micronutrients including IFA) from baseline until conception followed by daily prenatal IFA supplements until delivery. Height, weight, mid-upper arm circumference, triceps skinfold, and waist-hip circumference were measured at recruitment and at 1, 2, and 6 to 7 y PP. Body fat was assessed using bioelectric impedance at 6 to 7 y PP (n = 867). Group comparisons were made using analysis of variance or chi-square tests and general linear models for adjusted models. ResultsAt 6 to 7 y PP, we found significant differences (P < 0.05) by treatment group for mean percent fat (MM: 29.2%; IFA: 27.6%; FA: 27.8%), absolute fat mass (MM: 15.1 kg; IFA: 14.0 kg; FA: 14.3 kg), and prevalence of underweight based on BMI < 18.5 (MM: 5.8%; IFA: 10.3%; FA: 14.3%). Mean BMI and triceps skinfold thickness were higher in the MM group, but these differences were not statistically significant; the differences in absolute fat mass were also attenuated after controlling for body weight. No differences were observed for fat-free mass, prevalence of overweight (BMI >23), or other anthropometric measurements. ConclusionsPreconception MM supplementation was associated with lower prevalence of underweight and higher percent fat when compared with IFA and/or FA only. Preconception micronutrient interventions may have long-term effects on maternal health and merit further examination.This trial was registered at clinicaltrials.gov as NCT01665378.

A Novel LIBS Sensor for Sample Examinations on a Crime Scene.

In this work, we present a compact LIBS sensor developed for characterization of samples on a crime scene following requirements of law enforcement agencies involved in the project. The sensor operates both in a tabletop mode, for aside measurements of swabbed materials or taken fragments, and in handheld mode where the sensor head is pointed directly on targets at the scene. The sensor head is connected via an umbilical to an instrument box that could be battery-powered and contains also a color camera for sample visualization, illumination LEDs, and pointing system for placing the target in focus. Here we describe the sensor's architecture and functionalities, the optimization of the acquisition parameters, and the results of some LIBS measurements. On nano-plotted traces at silica wafer and in optimized conditions, for most of the elements the detection limits, in term of the absolute element masses, were found to be below 10 picograms. We also show results obtained on some representative materials, like fingerprints, swabbed soil and gunshot residue, varnishes on metal, and coated plastics. The last, solid samples were used to evaluate the depth profiling capabilities of the instrument, where the recognition of all four car paint layers was achieved.

Morphological characteristics of the kidneys of mature dogs (Canis Lupus Familiaris L., 1758)

Each biological species of animals is unique in its structure, which is due to the uniqueness of ecological habitats and the peculiarities of adaptation of homeostasis mechanisms to the influence of environmental factors. Subtle differences in the structural and functional components of organs found in different species of animals create a clear architecture for understanding the depth of biological processes. Research of species, breed and age macro- and microanatomical structures and their morphometric indicators of organs and systems should be considered as urgent tasks of modern morphology. The new data on the morphological indicators of organs discovered at the macro- and micro-levels make a certain contribution to the age-related, breed-related, comparative, experimental and clinical morphology of mammals. Urinary organs in the body of mammals play one of the leading roles in maintaining the physiological and biochemical status of the organism and homeostasis as a whole, which largely depends directly on the morphological and functional state of these organs. Increasingly, there is a need for comprehensive scientific studies of various departments of the urinary organs. The scientific article uses material that is a fragment of the planned research work of the department of normal and pathological morphology, hygiene and expertise “Development, morphology and histochemistry of animal organs in normal and pathological conditions”, state registration number 0120U100796. The article contains the results of the morphometric characteristics of the kidneys of sexually mature dogs – Canis lupus familiaris L., 1758. During the implementation of this work, complex research methods were applied: anatomical, histological, morphometric and statistical. For histological examination, a fragment of kidneys was selected, they were fixed in 10 % neutral formalin solution, Carnois and Buena fluid. In the future, dehydration was carried out in alcohols of increasing concentration and the procedure for sealing the organ was carried out according to generally accepted methods. Using a sled microtome, histological sections with a thickness of 7–10 μm were obtained. Processing of the results of histological sections was examined under a “Micros” light microscope with a digital camera at a magnification of × 100–400. The morphological study of the structural organs of the urinary system was studied on histological sections by the method of light microscopy in accordance with the requirements of the international principles of the “European Convention for the Protection of Vertebrate Animals Used in Experiments and Other Scientific Purposes” (Strasbourg, 1986), by the decision of the First National Congress on Bioethics (M. Kyiv, 2001), Law of Ukraine No. 692 “On the Protection of Animals from Cruel Treatment” (3447-IV) dated February 21, 2006. According to the histological structure, the kidneys of dogs are represented by renal corpuscles and renal tubules, which are made of epithelial cells. Organometric studies indicate that the absolute mass of kidneys in sexually mature dogs is 119.8 ± 6.48 g, relative – 0.74 ± 0.04 %. Morphometric studies of the kidney parenchyma in dogs have established that the average area of renal corpuscles is 4.89 ± 0.24 thousand μm², the area of the vascular glomerulus is 3.79 ± 0.18 thousand μm², the area of the Shumlyansky-Bowman capsule lumen is 1.12 ± 0.27 thousand μm². The average volume of renal bodies of the cortical substance is 1265.69 ± 239.34 thousand μm³. The number of renal corpuscles per conventional unit of area (5 mm²) is 20.8 ± 0.6 units. The aim of the work was to investigate the peculiarities of the morphogistological structure of the kidneys of sexually mature dogs. The research results will expand information about the morphological structure, and will serve for the development of issues of physiology, pathology and treatment of diseases of the urinary organs.

Neutrino mass sum rules from modular A4 symmetry

Modular symmetries offer a dynamic approach to understanding the flavor structure of leptonic mixing. Using the modular A4 flavor symmetry integrated in a type-II seesaw, we propose a simple and minimalistic model that restricts the neutrino oscillation parameter space and, most importantly, introduces a sum rule in the physical neutrino masses. When combined with the mass squared differences observed in neutrino oscillations, this sum rule determines the absolute neutrino mass scale. This has significant implications for cosmology, neutrinoless double beta decay experiments, and direct neutrino mass measurements. In particular, the model predicts ∑imi≈0.1 eV for both normal and inverted ordering, and thus can be fully probed by the current generation of cosmological probes in the upcoming years. Published by the American Physical Society 2024

Resting energy expenditure, body composition, and metabolic alterations in breast cancer survivors vs. healthy controls: a cross-sectional study

PurposeThis study aimed to investigate the difference in absolute and fat free mass (FFM)-adjusted resting energy expenditure (mREE) and body composition (body weight, fat mass (FM), FFM) between breast cancer survivors (BCs) and controls. Correlations with body composition were analyzed. We examined if survival year, or being metabolically dysfunctional were predictive variables.MethodsA cross-sectional analysis was conducted on 32 BCs ≤5 years post treatment and 36 healthy controls. Indirect calorimetry measured absolute mREE. Body composition was determined by BOD POD. FFM-adjusted mREE was calculated (mREE/FFM). The Harris-Benedict equation was used to predict REE and determine hyper−/hypometabolism (mREE/pREE). The database of the multidisciplinary breast clinic of the University Hospital of Antwerp was consulted for survival year and metabolic dysfunctions.ResultsBCs have similar absolute mREE and greater FFM-adjusted mREE compared to controls. Absolute mREE and body composition between BCs differed; adjusted mREE was similar. FFM correlated significantly with absolute mREE in BCs. A significant interaction term was found between survival year and FM for absolute mREE.ConclusionBCs have similar absolute mREE, but higher FFM-adjusted mREE. Differences in body composition between BCs are suggested to cause inter-individual variations. We suggest that increased FFM-adjusted mREE is caused by metabolic stress related to cancer/treatment. Accurate measurement of REE and body composition is advised when adapting nutritional strategies, especially in patients at risk for developing metabolic dysfunctions.

Low scale leptogenesis in singlet-triplet scotogenic model

The scotogenic model presents an elegant and succinct framework for elucidating the origin of tiny neutrino masses within the framework of the Standard Model, employing radiative corrections within the domain of the dark sector. We investigate the possibility of achieving low-scale leptogenesis in the singlet-triplet scotogenic model (STSM), where dark matter mediates neutrino mass generation. We initially considered a scenario involving two moderately hierarchical heavy fermions, N and Σ, wherein the lepton asymmetry is generated by the out-of-equilibrium decay of both particles. Our analysis indicates that the scale of leptogenesis in this scenario is similar to that of standard thermal leptogenesis and is approximately M N,Σ ∼ 109 GeV, which is comparable to the Type-I seesaw case. Further, we consider the case with three heavy fermions (N 2, N 2, and Σ) with the hierarchy M N 1 < M Σ ≪ MM N 2 , which yields the lower bound on heavy fermions up to 3.1 TeV, therefore significantly reduce the scale of the leptogenesis up to TeV scale. The only prerequisite is suppression in the N 1 and Σ Yukawa couplings, which causes suppressed washout effects and a small active neutrino mass of about 10-5 eV. This brings about the fascinating insight that experiments aiming to measure the absolute neutrino mass scale can test low-scale leptogenesis in the scotogenic model. Further, the hyperchargeless scalar triplet Ω provides an additional contribution to mass of the W-boson explaining CDF-II result.

The CHARA Array Interferometric Program on the Multiplicity of Classical Be Stars: New Detections and Orbits of Stripped Subdwarf Companions

Rapid rotation and nonradial pulsations enable Be stars to build decretion disks, where the characteristic line emission forms. A major but unconstrained fraction of Be stars owe their rapid rotation to mass and angular momentum transfer in a binary. The faint, stripped companions can be helium-burning subdwarf OB-type stars (sdOBs), white dwarfs (WDs), or neutron stars. We present optical/near-infrared Center for High Angular Resolution Astronomy (CHARA) interferometry of 37 Be stars selected for spectroscopic indications of low-mass companions. From multiepoch H- and/or K-band interferometry plus radial velocities and parallaxes collected elsewhere, we constructed 3D orbits and derived flux ratios and absolute dynamical masses of both components for six objects, quadrupling the number of anchor points for evolutionary models. In addition, a new wider companion was identified for the known Be + sdO binary 59 Cyg, while auxiliary Very Large Telescope Interferometer/GRAVITY spectrointerferometry confirmed circumstellar matter around the sdO companion to HR 2142. On the other hand, we failed to detect any companion to the six Be stars with γ Cas–like X-ray emission, with sdOB and main-sequence companions of the expected spectroscopic mass being ruled out for the X-ray-prototypical stars γ Cas and π Aqr, leaving elusive WDs as the most likely companions, as well as a likely explanation of the X-rays. No low-mass main-sequence close companions were identified for the other stars.

Influence of body mass normalization on the correlations between muscle cross-sectional area and physical performance outcomes in older women.

Normalization is a method used to account for body mass in clinical practice and research. It is unclear if thismethod will improve the correlation between muscle cross-sectional area (CSA) and physical performance. We examinedthe correlations between quadriceps muscle morphology parameters and physical performance outcomes in older women.Material and methods: Twenty older women participated in this study. Ultrasound imaging was used to measure quadricepsmuscle CSA and echo intensity. Muscle CSA was expressed as an absolute value (cm2) and as a relative value normalized tobody mass (cm2/kg). Physical performance was assessed from timed up-and-go and 6-min walk tests. Relative CSAwas significantly related to timed up-and-go scores (r=-0.489, p=0.029) and 6-min walking speed (r=0.606, p=0.005), whereasabsolute CSA was not significantly associated with these performances (r=-0.231, p=0.327 and r=0.373, p=0.105). There wasa significant correlation between absolute CSA and body mass (r=0.456, p=0.043). There were also significant correlationsbetween echo intensity and timed up-and-go scores (r=0.556, p=0.011) and 6-min walking speed (r=-0.484, p=0.031). Our study showed that relative CSA correlated better than absolute CSA with physical performance. These findingssupport the need to normalize measurements of muscle CSA to body mass in older adults.

Peculiarities of macro- and cytometric assessment of morphological structures of the domestic pig heart

The cardiovascular system, which includes the heart, is one of the essential systems of the human and animal body. With its participation, the blood supply of the organs takes place; it promotes the outflow of lymph from the organs and its transport into the veins, and it helps to implement the functions of the organs of immune protection, endocrine, and nervous systems. The work aims to conduct a macro-, histo-, and cytomorphometric assessment of the morphological structures of the heart of the domestic pig using complex research methods (macroscopic, histological, morphometric). Functionally mature, clinically healthy animals (n = 7) of Sus scrofa f. domestica were used for the work. According to organometallic studies, the absolute weight of a pig's heart is 487.4 ± 8.12 g; the relative weight is 0.290 ± 0.004%, and the net weight of the heart is 461.4 ± 8.0 g. According to its linear dimensions, a domestic pig's heart is elongated-narrowed (conical) type, as evidenced by the heart development index of 155.1 ± 6.3%. According to the functional load of the muscle tissues of the myocardium of the heart and its separate morphological structures (ventricles and atria) when performing particular work during spontaneous rhythmic contractions, the absolute mass of the ventricles and atria is different. The enormous mass is characteristic of the left ventricle, then the right, and the smallest for the left and right atria. Therefore, the ventricles of the heart are more functionally developed, as evidenced by the ratio coefficient (1:0.79) of the mass of the ventricles to the net mass of the heart, respectively, the ratio coefficient (1:0.21) of the mass of the atria to the net mass of the heart and the ratio coefficient (1:0.27) atrial mass to ventricular mass. Cardiomyocytes of the left ventricle have the most significant volume, cardiomyocytes of the right ventricle have a smaller volume, and cardiomyocytes of the atria have the smallest volume. Their nuclear volumes have similar values, respectively, in the left ventricle – 77.16 ± 2.01 μm3, the right ventricle – 76.02 ± 2.43 μm3, and the atrium – 75.97 ± 3.24 μm3, and the nuclear-cytoplasmic ratio is different from them: the smallest nuclear-cytoplasmic ratio, respectively characteristic of cardiomyocytes of the left ventricle, significantly more for cardiomyocytes of the right ventricle and significantly the most for cardiomyocytes of the atria. The scientific results of morphoarchitectonics, organo-, histo-, and cytometry of the heart of the domestic pig presented in the publication supplement the information on the morphological structure of the heart of domestic animals in the relevant sections of histology, comparative anatomy and are a significant contribution to clinical cardiology.

Deep Learning Enables Automatic Correction of Experimental HDX-MS Data with Applications in Protein Modeling.

Observed mass shifts associated with deuterium incorporation in hydrogen-deuterium exchange mass spectrometry (HDX-MS) frequently deviate from the initial signals due to back and forward exchange. In typical HDX-MS experiments, the impact of these disparities on data interpretation is generally low because relative and not absolute mass changes are investigated. However, for more advanced data processing including optimization, experimental error correction is imperative for accurate results. Here the potential for automatic HDX-MS data correction using models generated by deep neural networks is demonstrated. A multilayer perceptron (MLP) is used to learn a mapping between uncorrected HDX-MS data and data with mass shifts corrected for back and forward exchange. The model is rigorously tested at various levels including peptide level mass changes, residue level protection factors following optimization, and ability to correctly identify native protein folds using HDX-MS guided protein modeling. AI is shown to demonstrate considerable potential for amending HDX-MS data and improving fidelity across all levels. With access to big data, online tools may eventually be able to predict corrected mass shifts in HDX-MS profiles. This should improve throughput in workflows that require the reporting of real mass changes as well as allow retrospective correction of historic profiles to facilitate new discoveries with these data.

Assessing the performance of a targeted absolute quantification isotope dilution liquid chromatograhy tandem mass spectrometry assay versus a commercial nontargeted relative quantification assay for detection of three major perfluoroalkylsin human blood.

Isotope dilution ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) is commonly used for trace analysis of polyfluoroalkyl and perfluoroalkyl substances (PFAS) in difficult matrices. Commercial nontargeted analysis of major PFAS where relative concentrations are obtained cost effectively is rapidly emerging and is claimed to provide comparable results to that of absolute quantification using matrix matched calibration and isotope dilution UHPLC-MS/MS. However, this remains to be demonstrated on a large scale. We aimed to assess the performance of a targeted absolute quantification isotope dilution LC-MS/MS assay versus a commercial nontargeted relative quantification assay for detection of three major PFAS in human blood. We evaluated a population-based cohort of 503 individuals. Correlations were assessed using Spearman's rank correlation coefficients (rho). Precision and bias were assessed using Bland-Altman plots. For perfluorooctane sulfonic acid, the median concentrations were 5.10ng/mL (interquartile range [IQR] 3.50-7.24 ng/mL), the two assays correlated with rho 0.83. For perfluorooctanoic acid, the median concentrations were 2.14 ng/mL (IQR 1.60-3.0ng/mL), the two assays correlated with rho 0.92. For perfluorohexanesulfonate, the median concentrations were 5.5ng/mL (IQR 2.50-11.61 ng/mL), the two assays correlated with rho 0.96. The Bland-Altman statistical test showed agreement of the mean difference for the majority of samples (97-98%) between the two assays. Absolute plasma concentrations of PFAS obtained using matrix matched calibration and isotope dilution UHPLC-MS/MS show agreement with relative plasma concentrations from a nontargeted commercial platform by Metabolon. We observed striking consistency between the two assays when examining the associations of the three PFAS with cholesterol, offering additional confidence in the validity of utilizing the nontargeted approach for correlations with various health phenotypes.

Age- and sex-specific normative values for muscle mass parameters in 18,625 Brazilian adults.

The present study aimed to provide age- and sex-specific normative values for muscle mass parameters in Brazilian adults. Data pertaining to Brazilian adults (18+ years) who attended a nutritional clinical between January 2018 and July 2022 were analyzed. Muscle mass parameters were assessed using a bioimpedance digital scale (InBody 230, GBC BioMed NZ). Assessments were conducted under standard conditions, with participants refraining from physical exercise for 96 h and from eating or drinking (including water) for 8 h before evaluations. A total of 18,625 Brazilian adults were analyzed. Normative values for absolute and relative (height, m2) muscle mass and appendicular muscle mass (ASM) were calculated. In addition, specific age-related changes in muscle mass parameters were observed. In women, muscle mass peaked between the ages of 40-49 before gradually declining at an average rate of 5.7% per decade from the sixth decade of life onwards. ASM reached its peak earlier, during the third decade of life, and started to decline later, from 50 to 59 years. In contrast, absolute and ASM peaked at 40-49 years and declined from the sixth decade of life in men. Both sexes displayed a slightly greater decline in ASM than in muscle mass (13 vs. 12%). The present study provides normative values for absolute and relative muscle mass and ASM in Brazilian adults. Furthermore, important specific age-related changes in muscle mass parameters were observed. These data have public health implications and might serve as a reference tool to guide health professionals.

Molar mass determination via linear regression from SEC measurements: The case of polylactide, polycaprolactone and poly(2,2‐dimethylthrimethylene carbonate)

AbstractMolar mass correction coefficients (cc) were determined for calculating the absolute molar masses of polylactide (PLA), polycaprolactone (PCL), and poly(2,2‐dimethyltrimethylene carbonate) (PDTC) in the range of 2,5–190 kg/mol, using calibration based on polystyrene standards (PS). Linear PLAs, PCLs, and PDTCs with a wide range of molar masses were synthesized using tin (II) octoate and diol as a catalyst/initiator system. Size Exclusion Chromatography (SEC) coupled with a Refractive Index detector (SEC‐RI) or a Multi‐Angle Laser Light Scattering detector (SEC‐MALLS) was utilized to determine the relative molar mass or absolute molar mass of the samples under investigation. Additionally, for comparison, the absolute molar mass of low molar mass PLA, PCL, or PDTC was calculated based on end‐group analysis using the 1H NMR method. Correction coefficients were subsequently calculated by comparing the molar mass obtained from SEC‐MALLS and SEC‐RI. The calculated correction coefficients ranged from 0.40 to 0.87 and increased with the rising molar mass of the polymers. The derived equation could be used to evaluate the absolute molar masses from PS standards over a broad range for the analyzed polymers.

Физиологические показатели равнозубой бурозубки (Sorex isodon, Eulipotyphla) при непродолжительном пребывании в холодной воде

The physiological indices of small mammals caught in the natural environment are used to assess their living conditions, analyze the impact of various factors on populations, identify the mechanisms of animal adaptation to these factors, and for other purposes. At the same time, pitfall traps with water are often used to capture animals, especially shrews. The water temperature in such traps is characterized by rather low values. Even a relatively short stay of animals in cold water can lead to changes in their physiological parameters, which must be taken into account. The aim of this study was to evaluate such changes in shrews, on example of Sorex isodon. The variability of the physiological parameters of shrews during immersion in cold water is also of interest from the point of view of their physiology of thermoregulation. Shrews are among the smallest mammals, and therefore are characterized by high rates of heat loss. At the same time, these animals are active all year round and are widely distributed in the northern regions, where they are often exposed to acute cold exposure. The physiological mechanisms of adaptation of shrews to such conditions are still insufficiently studied. The study was conducted in late July-August 2016 on immature young-of-the-year even-toothed shrews (Sorex isodon Turov, 1924). The capture of shrews was carried out in the vicinity of Magadan (Russia). Before the start of the experiment, the caught animals had been kept individually for 2 days in plastic containers (37x26x26 cm) at room temperature with the provision of water and food ad libitum. Control animals were decapitated under ether anesthesia after keeping. The experimental animals were placed in a container with water preliminarily cooled to 4.5-9°C (6.5°C on average). After the swimming intensity of the shrews significantly decreased, they were also subjected to anesthesia and decapitation. The experimental group consisted of 22, and the control group consisted of 21 animals. The following physiological indices were determined in the shrews: blood glucose level, glycogen and lipid content in the liver, mass of internal organs and fat reserves, and the number of bone marrow cells in the femur. For statistical analyses, the Mann-Whitney U-test was used. The average swimming time of S. isodon in the experiment was 5.8 minutes. A relatively short immersion in cold water led to a significant change in the values of some physiological parameters in S. isodon. The indices of energy metabolism showed greatest differences between the control and experimental groups of animals. The level of blood glucose in S. isodon in the test group was significantly higher (See Fig. 1). On the contrary, the liver glycogen content in shrews sharply decreased after the experimental treatment. The level of this carbohydrate in the experimental group was 80% less than in the control. Acute cold exposure also provoked a fairly rapid change in the mass of fat reserves in S. isodon. The absolute and relative mass of the interscapular adipose tissue of S. isodon decreased by 11.9% and 10.7%, respectively, and that of the inguinal adipose tissue, by 20.9% and 18.8%, respectively (See Table 1). Differences in the mass of some shrew organs were also significant. The absolute and relative weight of the spleen was higher in the experimental animals. After exposure to cold water, S. isodon also had a higher relative heart mass than controls, although the differences in the absolute mass of this organ were insignificant. On the contrary, the absolute mass of shrew kidneys decreased after immersion in cold water. All other physiological indices showed no significant differences between the groups of control and experimental S. isodon. Thus, a relatively short stay of shrews in cold water provokes a significant change in the mass of their adipose tissue and some organs. High demand for glucose during acute cold stress leads to rapid depletion of liver glycogen. The rate of reduction of fat reserves in shrews under cold exposure is also quite high and exceeds that of most other mammals. It is known that in regions characterized by severe climatic conditions, the rate of reserve fat mobilization is of great importance for the survival of small mammals. The ability to quickly store and spend fat reserves, therefore, seems to be an important adaptation of shrews to living in cold climates.