Simulation of depth-dose curves and water equivalent ratios of energetic proton beams in cortical bone.

We have determined the depth-dose curve, penetration range, and water equivalent ratio for proton beams of clinical energies in cortical bone by means of a detailed and accurate simulation that combines molecular dynamics and Monte Carlo techniques. The fundamental input quantities (stopping power and energy loss straggling) for the simulation were obtained from a reliable electronic excitation spectrum of the condensed-phase target, which takes into account the organic and mineral phases that form it. Our simulations with these inputs, which are in excellent agreement with the scarce data available for a cortical bone target, deviate from simulations performed using other stopping quantities, such as those provided by the International Commission on Radiation Units and Measurements in its widely used Report No.

A 12-week multicomponent exercise program enhances frailty by increasing robustness, improves physical performance, and preserves muscle mass in older adults with HIV: MOVIhNG study.

Background: Our aim was to analyze the effects of a multicomponent exercise program (MEP) on frailty and physical performance in older adults with HIV (OAWH) since exercise can reverse frailty in the older population overall, but there is no data for OAWH.

Methods: A prospective longitudinal study with intervention and control group was designed. Sedentary adults 50 or over with and without HIV were included.

Development of Continuous Assessment of Muscle Quality and Frailty in Older Patients Using Multiparametric Combinations of Ultrasound and Blood Biomarkers: Protocol for the ECOFRAIL Study.

Background: Frailty resulting from the loss of muscle quality can potentially be delayed through early detection and physical exercise interventions. There is a demand for cost-effective tools for the objective evaluation of muscle quality, in both cross-sectional and longitudinal assessments. Literature suggests that quantitative analysis of ultrasound data captures morphometric, compositional, and microstructural muscle properties, while biological assays derived from blood samples are associated with functional information.

Resting metabolic rate in relation to incident disability and mobility decline among older adults: the modifying role of frailty.

Background: Alterations in resting metabolic rate (RMR), the largest component of daily total energy expenditure, with aging have been shown in various studies. However, little is known about the associations between RMR and health outcomes in later life.

Aims: To analyze whether RMR is associated with incident disability and mobility decline in a 10-year longitudinal study, as well as the moderating role of frailty in these associations.

Limits of stability and falls during a multicomponent exercise program in faller older adults: A retrospective cohort study.

Background/objetives: Multicomponent exercise programs have been demonstrated to prevent falls in older adults. However, the underlying responsible mechanisms are not clear. We aimed to analyze the association between changes in the limits of stability (LOS) as a relevant balance component, and falls occurrence during a multicomponent physical exercise program.

Frailty, depression risk and 10-year hospitalization in older adults. The FRADEA study.

Objectives: To determine whether the interaction between frailty status and depression risk is associated with hospitalization density in older adults.

Methods: Ongoing cohort study in 794 subjects aged over 70 years from Albacete (Spain). Data were collected on depression risk, frailty, hospitalizations, and covariates.

Energy Deposition around Swift Carbon-Ion Tracks in Liquid Water.

Energetic carbon ions are promising projectiles used for cancer radiotherapy. A thorough knowledge of how the energy of these ions is deposited in biological media (mainly composed of liquid water) is required. This can be attained by means of detailed computer simulations, both macroscopically (relevant for appropriately delivering the dose) and at the nanoscale (important for determining the inflicted radiobiological damage).

Psychological and Functional Impact of COVID-19 in Long-Term Care Facilities: The COVID-A Study.

Objective: To analyze the psychological and functional sequelae of the COVID-19 pandemic among older adults living in long term care facilities (LTCFs).

Design: Cohort longitudinal study SETTING ANT PARTICIPANTS: A total of 215 residents ≥ 65 years without moderate-to-severe cognitive impairment, living in five LTCFs in Albacete (Spain).

Measurements: Baseline on-site data were collected between March - June 2020 and three-month follow-up between June to September 2020.

[Frailty prevalence in hospitalized older adults. A systematic review.].

Background: Theres is uncertain evidence regarding the prevalence, measurement tools, outcomes, and efficacy of the interventions on frailty in hospitalized older adults. For this reason, we present the results of a systematic review about Frailty and Hospital, following the PRISMA methodology.

Methods: We found 2,050 articles published in PubMed.

Electronic excitation spectra of cerium oxides: from dielectric response functions to Monte Carlo electron transport simulations.

Nanomaterials made of cerium oxides CeO and CeO have a broad range of applications, from catalysts in automotive, industrial or energy operations to promising materials to enhance hadrontherapy effectiveness in oncological treatments. To elucidate the physico-chemical mechanisms involved in these processes, it is of paramount importance to know the electronic excitation spectra of these oxides, which are obtained here through high-accuracy linear-response time-dependent density functional theory calculations. In particular, the macroscopic dielectric response functions of both bulk CeO and CeO are derived, which compare remarkably well with the available experimental data.

Excitation and ionisation cross-sections in condensed-phase biomaterials by electrons down to very low energy: application to liquid water and genetic building blocks.

Electronic excitations and ionisations produced by electron impact are key processes in the radiation-induced damage mechanisms in materials of biological relevance, underlying important medical and technological applications, including radiotherapy, radiation protection in manned space missions and nanodevice fabrication techniques. However, experimentally measuring all the necessary electronic interaction cross-sections for every relevant material is an arduous task, so it is necessary having predictive models, sufficiently accurate yet easily implementable. In this work we present a model, based on the dielectric formalism, to provide reliable ionisation and excitation cross-sections for electron-impact on complex biomolecular media, considering their condensed-phase nature.

Relative Role of Physical Mechanisms on Complex Biodamage Induced by Carbon Irradiation.

The effective use of swift ion beams in cancer treatment (known as hadrontherapy) as well as appropriate protection in manned space missions rely on the accurate understanding of the energy delivery to cells that damages their genetic information. The key ingredient characterizing the response of a medium to the perturbation induced by charged particles is its electronic excitation spectrum. By using linear-response time-dependent density functional theory, we obtained the energy and momentum transfer excitation spectrum (the energy-loss function, ELF) of liquid water (the main constituent of biological tissues), which was in excellent agreement with experimental data.

Multiscale simulation of the focused electron beam induced deposition process.

Focused electron beam induced deposition (FEBID) is a powerful technique for 3D-printing of complex nanodevices. However, for resolutions below 10 nm, it struggles to control size, morphology and composition of the structures, due to a lack of molecular-level understanding of the underlying irradiation-driven chemistry (IDC). Computational modeling is a tool to comprehend and further optimize FEBID-related technologies.

Gait plasticity impairment as an early frailty biomarker.

Background/objectives: To assess whether gait plasticity and gait reserve, valid measures of gait adaptation to environmental stressors, are associated with frailty.

Design: Cross-sectional sub-analysis of the FISTAC study (Identification of the Physical Attributes of the Fear of Falling Syndrome).

Setting: Community-dwelling women from the Falls Unit of a Geriatrics Department.

COVID-19 outbreak in long-term care facilities from Spain. Many lessons to learn.

Background/objectives: To analyze mortality, costs, residents and personnel characteristics, in six long-term care facilities (LTCF) during the outbreak of COVID-19 in Spain.

Design: Epidemiological study.

Setting: Six open LTCFs in Albacete (Spain).

Energy Spectra of Protons and Generated Secondary Electrons around the Bragg Peak in Materials of Interest in Proton Therapy.

The number and energy of secondary electrons generated around the trajectories of swift protons interacting with biological materials are highly relevant in proton therapy, due to the prominent role of low-energy electrons in the production of biodamage. For a given material, electron energy distributions are determined by the proton energy; and it is imperative that the distribution of proton energy at depths around the Bragg peak region be described as accurately as possible. With this objective, we simulated the energy distributions of proton beams of clinically relevant energies (50-300 MeV) at depths around the Bragg peak in liquid water and the water-equivalent polymer poly(methyl methacrylate) (PMMA).

Benefits of a multicomponent Falls Unit-based exercise program in older adults with falls in real life.

Background/objectives: Multicomponent exercise programs are the cornerstone in preventing gait and balance impairments and falls in older adults. However, the effects of these programs in usual clinical practice have been poorly analyzed.

Design: 4-Month, twice-a-week multicomponent exercise program cohort study in real-life.

Angular and energy distributions of electrons produced in arbitrary biomaterials by proton impact.

We present a simple method for obtaining reliable angular and energy distributions of electrons ejected from arbitrary condensed biomaterials by proton impact. Relying on a suitable description of the electronic excitation spectrum and a physically motivated relation between the ion and electron scattering angles, it yields cross sections in rather good agreement with experimental data in a broad range of ejection angles and energies, by only using as input the target composition and density. The versatility and simplicity of the method, which can be also extended to other charged particles, make it especially suited for obtaining ionization data for any complex biomaterial present in realistic cellular environments.

Energy deposition of H and He ion beams in hydroxyapatite films: a study with implications for ion-beam cancer therapy.

Ion-beam cancer therapy is a promising technique to treat deep-seated tumors; however, for an accurate treatment planning, the energy deposition by the ions must be well known both in soft and hard human tissues. Although the energy loss of ions in water and other organic and biological materials is fairly well known, scarce information is available for the hard tissues (i.e.

Inelastic cross sections for low-energy electrons in liquid water: exchange and correlation effects.

Low-energy electrons play a prominent role in radiation therapy and biology as they are the largest contributor to the absorbed dose. However, no tractable theory exists to describe the interaction of low-energy electrons with condensed media. This article presents a new approach to include exchange and correlation (XC) effects in inelastic electron scattering at low energies (below ∼10 keV) in the context of the dielectric theory.

Water equivalent properties of materials commonly used in proton dosimetry.

The depth-dose distribution of proton beams in materials currently used in dosimetry measurements, such as liquid water, PMMA or graphite are calculated with the SEICS (Simulation of Energetic Ions and Clusters through Solids) code, where all the relevant effects in the evaluation of the energy deposited by the beam in the target are included, such as electronic energy-loss (including energy-loss straggling), multiple elastic scattering, electronic charge-exchange processes, and nuclear fragmentation interactions. Water equivalent properties are obtained for different proton beam energies and several targets of interest in dosimetry.

A study of the energy deposition profile of proton beams in materials of hadron therapeutic interest.

The energy delivered by a swift proton beam in materials of interest to hadron therapy (liquid water, polymethylmethacrylate or polystyrene) is investigated. An explicit condensed-state description of the target excitation spectrum based on the dielectric formalism is used to calculate the energy-loss rate of the beam in the irradiated materials. This magnitude is the main input in the simulation code SEICS (Simulation of Energetic Ions and Clusters through Solids) used to evaluate the dose as a function of the penetration depth and radial distance from the beam axis.

A combined molecular dynamics and Monte Carlo simulation of the spatial distribution of energy deposition by proton beams in liquid water.

We have evaluated the spatial distribution of energy deposition by proton beams in liquid water using the simulation code SEICS (Simulation of Energetic Ions and Clusters through Solids), which combines molecular dynamics and Monte Carlo techniques and includes the main interaction phenomena between the projectile and the target constituents: (i) the electronic stopping force due to energy loss to target electronic excitations, including fluctuations due to the energy-loss straggling, (ii) the elastic scattering with the target nuclei, with their corresponding energy loss and (iii) the dynamical changes in projectile charge state due to electronic capture and loss processes. An important feature of SEICS is the accurate account of the excitation spectrum of liquid water, based on a consistent solid-state description of its energy-loss-function over the whole energy and momentum space. We analyse how the above-mentioned interactions affect the depth distribution of the energy delivered in liquid water by proton beams with incident energies of the order of several MeV.