Zhu C et al. · Jul 1, 2026
Background Very high energy electron (VHEE) radiotherapy has gained growing interest owing to its potential to reach deep-seated targets and induce FLASH effect. Dose calculations can be performed using analytical or Monte Carlo (MC) methods. Analytical approaches enable rapid dose computation but suffer from limited accuracy in heterogeneous media, whereas MC methods provide high accuracy at the expense of substantial computational cost. Macro Monte Carlo (MMC) is a local-to-global method designed to improve dose calculation efficiency compared to general-purpose MC methods. In MMC, particle transport is based on precalculated transport data generated with general-purpose MC simulations on specific geometries, which is subsequently used to model particle transport over macroscopic steps within the absorber, avoiding computationally expensive microscopic tracking. MMC made it to a standard electron dose calculation engine in a commercial treatment planning system. However, to date, MMC has not been investigated for electron energies above 25 MeV. Purpose To develop and validate an MMC framework for VHEE radiotherapy that improves dose calculation efficiency while preserving accuracy compared to general-purpose MC methods for electron energies up to 250 MeV. Methods Local simulations were performed using EGSnrc with monoenergetic electron pencil beams incident perpendicularly on spherical geometries (0.2-25 MeV) with radii of 0.5-3 mm, and slab geometries (25-250 MeV) of 2 mm thickness, composed of various materials. Physical quantities including energy loss, lateral displacement, and angular distributions of primary and secondary particles were scored and stored in a database. This database was subsequently used to transport electrons step-by-step in the global simulations, employing slab-based transport at energies ≥25 MeV and switching to spherical geometries for electron energies 2 . MMC and EGSnrc dose calculations were also performed for two patient CT datasets. Comparisons between MMC and EGSnrc were conducted using integrated depth dose curves, lateral dose profiles, and 3D gamma analysis with 2%/1 mm and 2%/2 mm (global) criteria and a 10% dose threshold. All simulations were performed with statistical uncertainties below 1%, and computation times were recorded. Results Integrated depth dose curves and lateral dose profiles agreed within 2% of the maximum dose for all cases considered. For homogeneous and heterogeneous phantoms, MMC dose distributions yielded gamma passing rates above 97% (2%/1 mm) and 99% (2%/2 mm), respectively, compared to EGSnrc. For patient CT datasets, gamma passing rates exceeded 94% (2%/1 mm) and 97% (2%/2 mm). Overall, MMC achieved up to a 27-fold improvement in dose calculation efficiency compared to EGSnrc. Conclusions An MMC framework for VHEE dose calculation was successfully developed and validated for electron energies up to 250 MeV. The method demonstrated good agreement with EGSnrc while providing up to an order-of-magnitude improvement in dose calculation efficiency for the studied cases.
Medicine
Eriksson CE et al. · Jul 1, 2026
Noninvasive genetic sampling is widely used in ecology and conservation to identify predators and their diets but recovering individual-level information from consumed prey remains largely unexplored. We evaluated whether individual prey can be reliably genotyped from carnivore scats and assessed limitations associated with degraded and mixed DNA sources. We developed a 31-locus SNP panel optimized for genotyping degraded elk (Cervus canadensis) DNA using amplicon sequencing. We validated prey genotyping by matching elk genotypes recovered from carnivore scats ('carcass scats') collected at cougar (Puma concolor) kill sites to genotypes from corresponding elk carcasses. We also genotyped scats collected throughout the study area, identified as containing elk using DNA metabarcoding ('survey scats'). To avoid misidentifying multiple individuals in a scat as a unique genotype, we evaluated artificial mixtures of prey DNA to assess the ability to detect and filter samples containing mixed DNA. Elk genotypes recovered from carcass scats matched associated carcass genotypes, confirming accurate recovery of individual prey DNA from carnivore scats. Genotyping success was 88% in fresh carcass scats and 74% in survey scats of unknown age. Heterozygosity excess filtering removed most mixed samples, although one of 24 mixtures with equal DNA contributions from two individuals produced a false unique genotype. Our results demonstrate that carnivore scats can serve as a reliable source of individual-level prey DNA under appropriate conditions. This method provides a new data stream on individual prey mortality, predation rates, and scavenging dynamics, processes that have previously been difficult to quantify without invasive capture and collaring techniques.
Environmental Science
Kuchar L et al. · Jul 1, 2026
Fabry disease (FD, OMIM 301500) is an X-linked lysosomal storage disorder caused by deficient activity of lysosomal alpha-galactosidase A (AGAL, E.C. 3.2.1.22) due to pathogenic variants in the GLA gene (HGNC:4296, Xq22.1). Plasmatic deacylated globotriaosylceramide (lysoGb3) is elevated in FD patients as a reflection of lysosomal accumulation of Gb3. Specific (AGALopathic) GLA variants have been recently shown to accumulate within the secretory pathway and trigger endoplasmic reticulum stress and unfolded protein response rather than result in profound enzymatic deficiency. In part due to lack of integrative measures of clinical severity and biochemical/molecular parameters, specific impacts and consequences of X-chromosomal inactivation (XCI) on clinical manifestation in FD female heterozygotes still remain to be fully understood. Our study aimed at evaluation of XCI (% of inactive wt GLA allele) in untreated female FD heterozygotes with classic FD (n = 17), late-onset FD (n = 19) and individuals carrying GLA variants (p.(L394P) (n = 7), p.(A143T) (n = 4), and p.(D313Y) (n = 4)) with predominant AGALopathic effects. XCI was correlated with age of the patients, clinical phenotype, (residual) AGAL activity, and lysoGb3. AGAL activity corresponded to XCI independently of the type of the GLA mutation. The best separation of the clinical phenotypes (classic FD, late-onset FD and AGALopathy) was achieved by correlating XCI to the ratio of AGAL activity to lysoGb3. This three parametric calculated marker was then confronted with the Mainz Severity Score Index (MSSI) to generate an Integrative Clinical-Laboratory quotient (ICLq). ICLq discriminated the three female patient groups and demonstrated group-dependent differences in its average age-related increase.
Medicine
Toki R et al. · Jul 1, 2026
Background & aims Aminotransferases are widely used for metabolic dysfunction-associated steatotic liver disease (MASLD) evaluation, especially in type 2 diabetes mellitus (T2DM). Whether within-person seasonal variation affects classification near commonly used thresholds or relates to long-term metabolic outcomes remains unclear. Methods This registry-based cohort analysed monthly aspartate aminotransferase (AST) and alanine aminotransferase (ALT) measurements from 6039 adults with T2DM in the Japan Diabetes Clinical Data Management registry (2014-2020). Classification discordance across the 30 IU/L threshold was compared between winter-mean and summer-mean values. Individual seasonal amplitude was derived from seasonal-trend decomposition of multiply imputed monthly time series. Final glycated haemoglobin (HbA1c) and non-achievement of HbA1c Results Both AST and ALT showed significant seasonal variation, with the highest values in late autumn to early winter and the lowest in summer (p Conclusions AST and ALT exhibited reproducible seasonal variation peaking in late autumn to early winter, with approximately one in nine patients near the MASLD screening threshold reclassified depending on season. Greater seasonal amplitude, especially AST, was independently associated with poorer glycemic control, supporting season-aware interpretation in routine clinical practice.
Medicine
Bergdoll L et al. · Jul 1, 2026
Gating by voltage-dependent anion channels (VDAC) regulates mitochondrial metabolite flux, yet the structural mechanism underlying the open-to-closed transition remains unresolved. Here, we combine atomistic molecular dynamics (MD) simulations with double electron-electron resonance (DEER), using hydrostatic pressure as a reversible thermodynamic perturbation to shift conformational equilibria and stabilize low-population states. MD simulations reveal localized intrinsic flexibility within β-strands β1-β5 and β19, as well as in cytosolic loops connecting β6-β7 and β8-β9. High-pressure DEER measurements in lipid nanodiscs corroborate these predictions, identifying reversible, pressure-dependent distance changes within the pore lumen consistent with asymmetric deformation of the β-barrel. DEER-informed analysis of unbiased MD trajectories reveals an elliptical β-barrel conformation aligned parallel to the N-terminal helix that corresponds to the pressure-stabilized experimental state. ATP permeation simulations identify a free-energy barrier to metabolite translocation in this elliptical geometry, whereas diffusion through the circular open state is energetically favorable. These findings indicate that the elliptical conformation represents a transient gating-competent state rather than a fully closed channel. Together, our results support a gating mechanism driven by reversible β-barrel deformation and establish pressure-perturbed DEER integrated with MD as a general strategy for capturing transient, functionally relevant conformations of membrane channels.
Biochemistry, Genetics and Molecular Biology
Kvasov NA et al. · Jul 1, 2026
Mitochondria import the majority of their proteins from the cytosol, creating a fundamental challenge: precursor proteins must be synthesized, maintained in an import-competent state, and delivered to mitochondrial translocases without premature folding or aggregation. While mitochondrial protein import has been considered a post-translational process, growing evidence shows that a subset of mitochondrial proteins is synthesized in proximity to the organelle. We term this process co-translational targeting, or local translation. It may lead to direct structural coupling of protein synthesis and import, which we term co-translational translocation. New approaches, including selective ribosome profiling, proximity labeling, and RNA imaging, reveal that mitochondrial mRNA localization is highly dynamic and can be driven by both RNA-based and translation-dependent mechanisms. In contrast to the well-defined signal recognition particle pathway at the endoplasmic reticulum, mitochondrial targeting appears to rely on more flexible mechanisms shaped by nascent-chain properties, translation elongation, and coding-sequence features beyond the targeting signal. We discuss how these processes may support mitochondrial biogenesis and proteostasis while also creating vulnerabilities associated with ribosome stalling and precursor quality control. Together, recent findings position mitochondrial protein targeting as an integral part of cellular protein biogenesis and highlight key open questions in the coordination of translation and organelle function.
Biochemistry, Genetics and Molecular Biology
Jones RA et al. · Jul 1, 2026
Issue addressed Early childhood education and care (ECEC) centres are an ideal setting to promote key healthy eating and active living (HEAL) practices. Redesigning messages around such practices to be digital could help engage ECEC educators and assist with long-term implementation and reach. The aim of this study was to evaluate the potential impact of a HEAL-focused video initiative (Small Bites for Big Steps) on precursors to behaviour change including educators' self-efficacy, perceived behavioural control and behavioural intentions and the acceptability of the videos. Method A pilot randomised controlled trial was conducted with early childhood educators (56% aged 25-44 years, 98% female). Participants randomised to the intervention group received on average 3-4 weekly videos promoting HEAL practices, whilst participants in the control group maintained usual practice. Educators' self-efficacy, perceived behavioural control, and behavioural intention were assessed using questionnaires at baseline and post-intervention (9 weeks). Data were analysed using Mann Whitney U tests in SPSS and thematic analysis. Acceptability data were collected using questionnaires, focus groups, interviews, and Vimeo analytics. Results One hundred and six educators from 16 ECEC services were recruited. Exploratory efficacy analysis found significant improvements from baseline to post-intervention between groups for healthy eating/drinking perceived behavioural control. At post-intervention, there was a significant difference between intervention and control groups for healthy eating/drinking behavioural intention, physical activity behavioural intention, and overall behavioural intention. No significant between group differences were observed for changes in perceived behavioural control relating to physical activity or for any self-efficacy measures. Educators valued the content, length and approach of the videos. Limitations identified from the qualitative data included technical difficulties and cultural appropriateness. Conclusions This video-based intervention positively influenced educators' perceived behavioural control and behavioural intentions, key precursors to behaviour change. The video suite was acceptable to educators. SO WHAT?: Redesigning HEAL messages into video resources may support ECEC educators to promote and implement these practices to young children and their families/carers.
Medicine
Chen W et al. · Jul 1, 2026
Chimeric Antigen Receptor (CAR)-T cell is an immunotherapy which revolutionised the treatment of relapsed/refractory lymphoma and leukaemia. It is shown to have a higher response rate, higher mid-to-long term overall survival, and lower toxicity than standard treatments. However, due to a lack of dose-limiting toxicity (DLT) and unclear dose-effect relationship, traditional phase I designs of clinical trials cannot lead to accurate selections of the optimal dose (OD). Beside clinical outcomes, the CAR-T cell expansion from serial blood samples is measured at various time points. We propose a novel early phase dose-finding design for CAR-T cells, using both toxicity and activity endpoints to locate the OD. The number of CAR-T cells measured in the peripheral blood is used to indicate activity, which is more sensitive than the short-term clinical responses traditionally used. A Bi-Exponential model is used for the repeated measures of the number of cells for each patient, and is estimated under a Bayesian framework. The model is motivated by biological concerns and is flexible enough to accommodate different shapes of the cell-expansion curve. Three criteria for activity are considered: (1) the number of cells at specific time points, (2) the duration before all cells are eliminated, (3) the area under the cell-expansion curve. Simulation studies show that the OD can be selected with high accuracy even under small sample sizes.
Medicine
Molina OJ et al. · Jul 1, 2026
Modification of lysine residues is a common strategy in protein engineering, whether to prevent posttranslational modifications, control bioconjugation, or improve crystallization. The standard genetic approach-replacement with arginine by site-directed mutagenesis-preserves positive charge but alters other physicochemical attributes and cannot address the N-terminal amino group. Here, we characterize reductive methylation as a chemical alternative. This reaction converts every primary amino group to a dimethylamino group rapidly under mild aqueous conditions. Using human ribonuclease 1 and a cytotoxic variant engineered to evade the endogenous ribonuclease inhibitor as model systems, we assess the effects of complete dimethylation on thermostability, enzymatic catalysis, protein-protein interaction, compatibility with bioconjugation, cellular uptake, and intracellular persistence. Dimethylation preserves thermostability and a protein-protein interaction. Enzymatic catalysis, in contrast, is reduced by 10 2 - to 10 3 -fold, consistent with the role of catalytic lysine residues. Dimethylation is fully compatible with bioconjugation chemistry. Dimethylated and unmodified ribonucleases show comparable uptake and persistence in human cells. These findings establish reductive methylation as a practical and conservative strategy for lysine modification in protein and peptide engineering and support its use in applications such as biological proteolysis-targeting chimeras (bioPROTACs).
Biochemistry, Genetics and Molecular Biology
Mooney T et al. · Jul 1, 2026
This study reports biceps femoris long head (BFlh) fascicle length and eccentric knee flexion strength changes following a 9-week in-season low-volume resistance training intervention in elite under-20-year-old (U20) male Gaelic footballers with and without previous hamstring injury. We included 26 male Gaelic footballers (age = 18.5 ± 0.5 years; height = 183.1 ± 5.1 cm; body mass = 79.2 ± 7.9 kg) in this study, with 10 of these participants reporting previous hamstring injuries within the last 12 months. Participants performed two sets of four Nordic hamstring exercise (NHE) repetitions and three sets of six staggered-stance Romanian deadlift (RDL) repetitions once per week for nine weeks. Before and after the intervention, BFlh fascicle length was assessed via ultrasound and eccentric knee flexion strength was measured during the NHE. We ran separate linear mixed-effects models for BFlh fascicle length and eccentric knee flexion strength, with fixed-effects of time (baseline and follow-up), limb-type (previously injured and contralateral uninjured limbs of previously injured participants and between-limb average of uninjured participants) and the time*limb-type interaction. The linear mixed-effects model for BFlh fascicle length revealed a significant main effect of time (β = 0.31 cm; SE = 0.15 cm; p = 0.04), while the time*limb-type interaction was not statistically significant. The linear mixed-effects model for eccentric knee flexion strength revealed no significant increase in eccentric knee flexion strength (β = 9.53 N, SE = 12.97 N, p = 0.47), while the time*limb-type interaction was not statistically significant. These findings suggest changes to BFlh fascicle length and eccentric knee flexion strength from baseline to follow-up were comparable across all limb-types.
Medicine