Extending deterministic transport capabilities for very-high and ultra-high energy electron beams.

Focused Very-High Energy Electron (VHEE, 50-300 MeV) and Ultra-High Energy Electron (UHEE, > 300 MeV) beams can accurately target both large and deeply seated human tumors with high sparing properties, while avoiding the spatial requirements and cost of proton and heavy ion facilities. Advanced testing phases are underway at the CLEAR facilities at CERN (Switzerland), NLCTA at Stanford (USA), and SPARC at INFN (Italy), aiming to accelerate the transition to clinical application. Currently, Monte Carlo (MC) transport is the sole paradigm supporting preclinical trials and imminent clinical deployment. In this paper, we propose an alternative: the first extension of the nuclear-reactor deterministic chain NJOY-DRAGON for VHEE and UHEE applications. We have extended the Boltzmann-Fokker-Planck (BFP) multigroup formalism and validated it using standard radio-oncology benchmarks, complex assemblies with a wide range of atomic numbers, and comprehensive irradiation of the entire periodic table. We report that [Formula: see text] of water voxels exhibit a BFP-MC deviation below [Formula: see text] for electron energies under [Formula: see text]. Additionally, we demonstrate that at least [Formula: see text] of voxels of bone, lung, adipose tissue, muscle, soft tissue, tumor, steel, and aluminum meet the same criterion between [Formula: see text] and [Formula: see text]. For water, the thorax, and the breast intra-operative benchmark, typical average BFP-MC deviations of [Formula: see text] and [Formula: see text] were observed at [Formula: see text] and [Formula: see text], respectively. By irradiating the entire periodic table, we observed similar performance between lithium ([Formula: see text]) and cerium ([Formula: see text]). Deficiencies observed between praseodymium ([Formula: see text]) and einsteinium ([Formula: see text]) have been reported, analyzed, and quantified, offering critical insights for the ongoing development of the Evaluated Nuclear Data File mode in NJOY.

Feasibility of a multigroup Boltzmann-Fokker-Planck solution for electron beam dose calculations.

Legacy nuclear-reactor Boltzmann solvers start clinical deployment as an alternative to Monte Carlo (MC) codes and Fermi-Eyges semiemprical models in radiation oncology treatment planning. Today's certified clinical solvers are limited to photon beams. In this paper, ELECTR, a state-of-the-art multigroup electron cross sections generation module in NJOY is presented and validated against Lockwood's calorimetric measurements, EGS-nrc and GEANT-4 for 1-20 MeV unidirectional electron beams. The nuclear-reactor DRAGON-5 solver is upgraded to access the library and solve the Boltzmann-Fokker-Planck (BFP) equation. A variety of heterogeneous radiotherapy and radiosurgery phantom configurations were used for validation purpose. Case studies include a thorax benchmark, that of a typical breast Intra-Operative Radiotherapy and a high-heterogeneity patient-like benchmark. For all beams, [Formula: see text] of the water voxels satisfied the American Association of Physicists in Medicine accuracy criterion for a BFP-MC dose error below [Formula: see text]. At least, [Formula: see text] of adipose, muscle, bone, lung, tumor and breast voxels satisfied the [Formula: see text] criterion. The average BFP-MC relative error was about [Formula: see text] for all voxels, beams and materials combined. By irradiating homogeneous slabs from [Formula: see text] (hydrogen) to [Formula: see text] (einsteinium), we reported performance and defects of the CEPXS mode [US. Sandia National Lab., SAND-89-1685] in ELECTR for the entire periodic table. For all Lockwood's benchmarks, NJOY-DRAGON dose predictions are within the experimental data precision for [Formula: see text] of voxels.

Pemmican, an endurance food: Past and present.

Pemmican is a meat product principally comprised of dried meat and fat that has served as a source of sustenance in cold, harsh climates and/or a means of preservation of meat for some Indigenous peoples, fur traders, polar explorers, military and police. Pemmican is acclaimed for its high nutrient density and long shelf life. However, for a meat product that has historically played a significant role and is often cited as the ultimate endurance food, there is a surprising paucity of scientific literature. The present study aims to review the literature to document the history of pemmican, its preparation, nutritional evaluation and additional use in the diet of animals. In view of food security and crisis situations in the world today, meat science may have a role to play in reviving, reformulating and potentially developing new processing strategies for a product like pemmican as a culturally appropriate food, with extended use as emergency provisions or for endurance athletes.

High relaxivities and strong vascular signal enhancement for NaGdF4 nanoparticles designed for dual MR/optical imaging.

Near-infrared (NIR)-to-NIR upconverting NaY(Gd)F4 :Tm(3+) ,Yb(3+) paramagnetic nanoparticles (NPs) are efficiently detected by NIR imaging techniques. As they contain Gd(3+) ions, they also provide efficient "positive" contrast in magnetic resonance imaging (MRI). Water-dispersible small (≈25 nm, "S-") and ultrasmall (<5 nm diam., "US-") NaY(Gd)F4 :Tm(3+) ,Yb(3+) NPs are synthesized by thermal decomposition and capped with citrate. The surface of citrate-coated US-NPs shows sodium depletion and high Gd elemental ratios, as confirmed by a comparative X-ray photoelectron spectroscopy (XPS)/neutron absorption analysis study. US-NaGd0.745 F4 :Tm0.005 ,Yb0.25 NPs have hydrodynamic diameters close to that measured by TEM, with the lowest relaxometric ratios (r2 /r1 = 1.18) reported for NaGdF4 nanoparticle suspensions (r1 = 3.37 mM(-1) s(-1) at 1.4 T and 37 °C). Strong relaxivity peaks in the range of 20 (0.47 T) - 300 MHz (7.05 T) are revealed in nuclear magnetic resonance dispersion profiles, with high r2 /r1 ratios at increasing field strengths for S-NPs. This indicates the superiority of US-NPs over S-NPs for achieving high positive contrast at clinical MRI field strengths. I.-v. injected citrate-coated US-NPs evidence long blood retention times (>90 min) in mice. Biodistribution studies (48 h, 8 d) show elimination through the reticuloendothelial and urinary systems, similarly to other citrate-capped US-NP systems. In summary, upconverting NaY(Gd)F4 :Tm(3+) ,Yb(3+) nanoparticles have promising luminescent, relaxometric and blood-retention properties for dual MRI/optical imaging.

Imaging: high relaxivities and strong vascular signal enhancement for NaGdF4 nanoparticles designed for dual MR/optical imaging (Adv. Healthcare Mater. 11/2013).

Tripositive gadolinium-ion doped NIR-to-NIR upconverting paramagnetic nanoparticles are efficiently detected are NIR imaging techniques but can also provide efficient "positive" contrast in MRI. On page 1478 John A. Capobianco, Marc-André Fortin, and co-workers show that citrate-coated nanoparticles present the lowest relaxometric ratios reported for NaGdF4 nanoparticle suspensions. IV-injected nanoparticles evidence long blood retention times in mice while biodistribution studies show elimination through the reticuloendothelial and urinary systems.