Purpose/Objective(s) Radiotherapy (RT) is an effective treatment for residual lymphoma early after CD19 chimeric antigen receptor T cell therapy (CAR T). However, there are concerns regarding the effect of RT on CAR T. We investigated the effect of different RT planning techniques on the dose to circulating blood to develop CAR T sparing RT using a published computational framework to compute hematological doses (HEDOS) Materials/Methods We analyzed 33 RT treatment plans for 11 lesions. Each lesion was planned with 3 RT techniques. Technique A: a conventional VMAT plan, B: a blood sparing technique with lower number of arcs and dose optimization for blood vessels (BV) and blood rich organs (BRO) and C: the same as B but delivered with Flattening Filter Free (FFF) beams to increase dose rate (DR) and reduce beam on time (BOT). Fractional blood doses were calculated using HEDOS, which simulates individual blood particles as they travel through the body, dictated by intra- and inter-organ blood flow. The % of blood volume that received 0, 0.05 and 0.5 Gy was estimated for each RT technique. Wilcoxon test was used to test for significance. Results BV dose was reduced by B & C, with wide variation between different cases. However, the differences between the mean BV dose of the whole group did not reach statistical significance. Techniques B & C reduced BOT, especially C due to its higher DR (1400 vs 600 MU/min). BOT reduction had the largest influence on the volume of irradiated blood and thus C significantly reduced the blood dose compared to A & B (Table 1). The % blood volume receiving 0 Gy was highest for C. C also reduced the blood volume that received > 0.05 Gy / fraction, a dose level that can induce cell death/inactivation due to the highly radiosensitive nature of lymphocytes. Conclusion This is the first study to develop a blood sparing (and potentially CAR T sparing) RT by modifying treatment parameters to account for the circulating nature of the blood. Using a dynamic dose calculation method, BOT has a large effect compared to other modifications. Reducing BOT to < 60 seconds had the greatest blood dose-sparing effect. This blood sparing RT could have other potential applications such as reducing risk for lymphopenia after RT.

Spinel Cobalt Vanadate CoV$_2$O$_4$ has been grown on (001) SrTiO$_3$ substrates. Using torque magnetometry experiments, we find that the previously observed temperature induced anisotropy change, where the easy axis changes from the out of plane [001] direction to a biaxial anisotropy with planar <100> easy axes, occurs in a gradual second-order structural phase transition. This work characterizes this transition and the magnetic anisotropies in the (001), (100), and (-110) rotation planes, and explores their field dependence up to 30~T. Below 80~K, hysteretic features appear around the hard axes, i.e., the out-of-plane direction in (-110) and (010) rotations and the planar <110> directions in (001) rotations. This is due to a Zeeman Energy that originates from the lag of the magnetization with respect to the applied magnetic field as the sample is rotated. The appearance of the hysteresis, which persist up to very high fields, shows that the anisotropy at low temperature is rather strong. Additionally, field dependent distortions to the symmetry of the torque response in increasing applied fields shows that magnetostriction plays a large role in determining the direction and magnitude of the anisotropy.

Low-temperature optical spectroscopy in applied magnetic fields provides clear evidence of magnetoelastic coupling in the spin ice material Ho2Ti2O7. In far infrared (IR) reflectometry measurements, we observe fielddependent features around 30, 61, 72, and 78 meV, energies corresponding to crystal electronic field (CEF) doublets. The calculations of the crystal field Hamiltonian model confirm that the observed features in IR spectra are consistent with magnetic-dipole-allowed excitations from the ground state to higher 5I8 CEF levels. We present the CEF parameters that best describe our field-dependent IR reflectivity measurements. Additionally, we identify a weak field-dependent shoulder near one of the CEF doublets. This indicates that this level is split even in zero field, which we associate with a vibronic bound state. Modeling of the observed splitting shows that the phonon resides at slightly lower energy compared to the CEF level that it couples to, which is in contrast with previously published inelastic neutron measurements. The magnetic field dependence of the vibronic state shows a gradual decoupling of the phonon with the CEF level as it shifts. This approach should work in pyrochlores and other systems that have magnetic dipole transitions in the IR spectroscopic range, which can elucidate the presence and the ability to tune the nature of vibronic states in a wide variety of materials.

The single-ion anisotropy and magnetic interactions in spin-ice systems give rise to unusual non-collinear spin textures, such as Pauling states and magnetic monopoles. The effective spin correlation strength (Jeff) determines the relative energies of the different spin-ice states. With this work, we display the capability of capacitive torque magnetometry in characterizing the magneto-chemical potential associated with monopole formation. We build a magnetic phase diagram of Ho2Ti2O7, and show that the magneto-chemical potential depends on the spin sublattice (α or β), i.e., the Pauling state, involved in the transition. Monte Carlo simulations using the dipolar-spin-ice Hamiltonian support our findings of a sublattice-dependent magneto-chemical potential, but the model underestimates the Jeff for the β-sublattice. Additional simulations, including next-nearest neighbor interactions (J2), show that long-range exchange terms in the Hamiltonian are needed to describe the measurements. This demonstrates that torque magnetometry provides a sensitive test for Jeff and the spin-spin interactions that contribute to it.

LaVO3 (LVO) has been proposed as a promising material for photovoltaics because its strongly correlated d electrons can facilitate the creation of multiple electron-hole pairs per incoming photon, which would lead to increased device efficiency. In this study, we intentionally grow off-stoichiometric LVO films by changing the growth conditions such as laser fluence. Our aim is to study how deviating La:V stoichiometries affect the electronic properties of LVO thin films. We find that the off-stoichiometry clearly alters the physical properties of the films. Structural characterization shows that both La-rich and V-rich films have different levels of structural distortion, with La-rich (V-rich) films showing a larger (smaller) out-of-plane lattice parameter compared to what one would expect from epitaxial strain effects alone. Both types of films show deviation from the behavior of bulk LVO in optical measurement, i.e., they do not show signatures of the expected long range orbital order, which can be a result of the structural distortions or the presence of structural domains. In transport measurements, La-rich films display clear signatures of electronic phase separation accompanying a temperature induced metal-insulator transition, while V-rich films behave as Mott insulators. The out-of-plane lattice parameter plays a crucial role in determining the transport properties, as the crossover from Mott-insulating to disorder-induced phase-separated behavior occurs around a lattice parameter value of 3.96 Å, quite different from what has been previously reported.

Becker muscular dystrophy (BMD) is the milder allelic variant of Duchenne muscular dystrophy, with higher dystrophin levels. To anticipate on results of interventions targeting dystrophin expression it is important to know the natural variation of dystrophin expression between different muscles and over time. Dystrophin was quantified using capillary Western immunoassay (Wes) in the anterior tibial (TA) muscle of 37 BMD patients. Variability was studied using two samples from the same TA biopsy site in nine patients, assessing nine longitudinal TA biopsies, and eight simultaneously obtained vastus lateralis (VL) muscle biopsies. Measurements were performed in duplicate with two primary antibodies. Baseline dystrophin levels were correlated to longitudinal muscle strength and functional outcomes. Results showed low technical variability and high precision for both antibodies. Dystrophin TA levels ranged from 4.8 to 97.7%, remained stable over a 3–5 year period, and did not correlate with changes in longitudinal muscle function. Dystrophin levels were comparable between TA and VL muscles. Intra-muscle biopsy variability was low (5.2% and 11.4% of the total variability of the two antibodies). These observations are relevant for the design of clinical trials targeting dystrophin production, and may urge the need for other biomarkers or surrogate endpoints.

A nanoscale membrane enables exploration of large tensile strains on complex oxides

Geometrically frustrated systems have an incompatibility between the lattice geometry and the magnetic interactions, resulting in macroscopically degenerate ground-state manifolds.In pyrochlore titanates (such as Ho2Ti2O7), large single ion anisotropy leads to a highly degenerate two-in/two-out spin ice state.Degeneracy is lifted when magnetic fields are applied, leading to transitions between various spin textures that depend on the direction of the field, and to emergent excitations equivalent to magnetic monopoles.There is an enticing potential of harnessing these monopoles, as information carriers; to realize these thin films are required.I will demonstrate the applicability of torque magnetometry in probing specific spin textures hosted by the spin ice state, and the transient states associated with transitions between them.High quality single crystals and thin films have been measured at temperatures down to 20 mK in applied fields up to 11 T. Sample rotation allowed for application of magnetic fields along various crystallographic directions of the samples.Utilizing reported results from neutron scattering as a starting point I have developed a phenomenological model that describes the anisotropic magnetic phase diagram of the bulk spin ice.This sensitive technique is highly suitable for thin film characterization; hence, this paves the way to compiling temperature-field phase diagrams, detailing thin film spin ice physics as a function of film thickness and strain.

We present an extensive study on the effect of substrate orientation, strain, stoichiometry, and defects on spin-ice physics in Ho2Ti2O7 thin films grown onto yttria-stabilized-zirconia substrates. We find that growth in different orientations produces different strain states in the films. All films exhibit similar c-axis lattice parameters for their relaxed portions, which are consistently larger than the bulk value of 10.1 Å. Transmission electron microscopy reveals antisite disorder and growth defects to be present in the films, but evidence of stuffing is not observed. The amount of disorder depends on the growth orientation, with the (110) film showing the least. Magnetization measurements at 1.8 K show the expected magnetic anisotropy and saturation magnetization values associated with a spin ice for all orientations; shape anisotropy is apparent when comparing in- and out-of-plane directions. Significantly, only the (110)-oriented films display the hallmark spin-ice plateau state in magnetization, albeit less well defined compared to the plateau observed in a single crystal. Neutron-scattering maps on the more disordered (111)-oriented films show the Q=0 phase previously observed in bulk materials, but the Q=X phase giving the plateau state remains elusive. We conclude that the spin-ice physics in thin films is modified by defects and strain, leading to a reduction in the temperature at which correlations drive the system into the spin-ice state.

We report on the epitaxial film growth and characterization of CoV$_2$O$_4$, a near-itinerant spinel vanadate, grown on (001) SrTiO$_3$. The symmetry lowering of the unit cell from cubic in the bulk to orthorhombic in the films results in dramatic differences in the magnetic anisotropy compared to bulk, as determined from structural and magnetic characterization. Bulk cubic CoV$_2$O$_4$ has been found to defy predictions by showing orbital degeneracy seemingly lasting to very low temperatures, with only small anomalies in magnetization and neutron experiments signaling a possible spin/orbital glass transition at T = 90 K. In epitaxial thin films presented in this paper, structurally tuning the CoV$_2$O$_4$ away from cubic symmetry leads to a completely different low temperature non-collinear ground state. Via magnetization and neutron scattering measurements we show that the 90 K transition is associated with a major spin reorientation away from the ferrimagnetic easy axis [001] to the [110] direction. Furthermore, the V-spins cant away from this direction with extracted perpendicular moments providing evidence of a larger canting angle compared to bulk. This result indicates that compressive strain pushes the system deeper into the insulating state, i.e., away from the localized - itinerant crossover regime.

We report on a study of the structural and magnetic properties of strained Ho$_2$Ti$_2$O$_7$ thin films. Structural characterization via lab-based and synchrotron x-ray diffraction confirms the epitaxial growth of our films and shows a critical thickness slightly below 50 nm. Neutron scattering maps of our films show a $Q = 0$ structure indicating that the spin ice physics is preserved in the films. Magnetization measurements with a field applied in the film plane confirm this and show markedly linear behavior in the $chi T~ vs. 1/T$ curve for $2~text{K} leq T leq 5~text{K}$ similar to that previously observed by others in single crystals. Furthermore, for fields applied along the [111] direction, out of the film plane, we observe a more parabolic behavior, which is treated as two linear regions with an interesting slope change around 3 K that could be a signature of the transition to the paramagnetic `hotu0027 phase reported by others in single crystals. From the linear regions we extract the value for nearest neighbor superexchange interactions (J$_S$) between the Ho ions. We find similar values compared to reported bulk values for the interaction strength, again signaling the preservation of spin ice physics in strained thin films.

Hollow channel plasma wakefield acceleration is a proposed method to provide high acceleration gradients for electrons and positrons alike: a key to future lepton colliders. However, beams which are misaligned from the channel axis induce strong transverse wakefields, deflecting beams and reducing the collider luminosity. This undesirable consequence sets a tight constraint on the alignment accuracy of the beam propagating through the channel. Direct measurements of beam misalignment-induced transverse wakefields are therefore essential for designing mitigation strategies. We present the first quantitative measurements of transverse wakefields in a hollow plasma channel, induced by an off-axis 20 GeV positron bunch, and measured with another 20 GeV lower charge trailing positron probe bunch. The measurements are largely consistent with theory.

We report on a study of the inelastic scattering properties of (001) and (111) Ho$_2$Ti$_2$O$_7$ single crystals at room temperature. Structural and compositional analysis along with absorption measurement confirms single crystalline phase of all samples. Room temperature polarized Raman measurements were performed on crystals in non-resonant and two different resonant conditions by using six different laser excitation lines. Lorentzian model fitting analysis is performed on all measured spectra in order to identify the difference in the Raman scattering cross-section in resonant and non-resonant conditions. Variations in the fitting parameters on account of different polarization configurations and crystallographic orientations has helped identifying their symmetry if present. Several possible scattering pathways are discussed in order to qualitatively explain the anomalous scattering results in Ho$_2$Ti$_2$O$_7$