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Selected Publications
Extreme-ultraviolet light has become more important for advancements in modern computer chip manufacturing, and as such, there needs to be more access to extreme-ultraviolet sources for observing properties of novel technology materials. Some of these extreme-ultraviolet sources need to have the ability to tune the polarization for observing dichroic properties of materials such as magnetism. We present a compact extreme-ultraviolet tabletop source, based on high harmonic generation, designed for use in polarization-sensitive imaging. The source is able to generate circularly polarized harmonics using the MAch-ZEhnder-Less for Threefold Optical Virginia spiderwort apparatus. The linearly polarized 42 and 52 eV beams have been optimized, achieving an average power of 19.4 and 8.0 nW, respectively. Using the 42 eV linearly polarized beam for ptychography, we have imaged a Siemens star test resolution target and obtained a resolution of 160 nm.
Background
Response curves are widely used in biomedical literature to summarize time-dependent outcomes, yet raw data are not always available in published reports. Meta-analysts must frequently extract means and standard errors from figures and estimate outcome measures like the area under the curve (AUC) without access to participant-level data. No standardized method exists for calculating AUC or propagating error under these constraints.
Methods
We evaluate two methods for estimating AUC from figure-derived data: (1) a trapezoidal integration approach with extrema variance propagation, and (2) a Monte Carlo method that samples plausible response curves and integrates over their posterior distribution. We generated 3,920 synthetic datasets from seven functional response types commonly found in glycemic response and pharmacokinetic research, varying the number of timepoints (4–10) and participants (5–40). All response curves were normalized to a true AUC of 1.0.
Results
The standard method consistently underestimated the true AUC, especially in curves with skewed or long-tailed structures. Monte Carlo method produced near-unbiased estimates with tighter alignment to the known AUC across all settings. Increasing the number of datapoints and participants improved performance for both methods, but the Monte Carlo approach retained robustness even under sparse conditions.
Conclusion
This is the first large-scale benchmarking of AUC estimation accuracy from graphically extracted data. The Monte Carlo method outperforms standard approaches in both accuracy and uncertainty quantification. We recommend its adoption in meta-analytic contexts where only figure-derived data are available and advocate for improved data sharing practices in primary publications.
Recent breakthroughs in nuclear fusion, specifically the report of reactions exceeding scientific breakeven at the National Ignition Facility (NIF), highlight the potential of inertial fusion energy (IFE) as a sustainable and virtually limitless energy source. However, further progress in IFE requires characterization of defects in ablator materials and how they affect fuel capsule compression. Voids within the ablator can degrade energy yield, but their impact on the density distribution has primarily been studied through simulations, with limited high-resolution experimental validation. To address this, we used the x-ray free-electron laser (XFEL) at the matter in extreme conditions (MECs) instrument at the Linac coherent light source (LCLS) to capture 2D x-ray phase-contrast (XPC) images of a void-bearing sample with a composition similar to inertial confinement fusion (ICF) ablators. By driving a compressive shockwave through the sample using MEC's long-pulse laser system, we analyzed how voids influence shockwave propagation and density distribution during compression. To quantify this impact, we extracted phase information using two phase retrieval algorithms. First, we applied the contrast transfer function (CTF) method, paired with Tikhonov regularization and a fast optimization approach to generate an initial phase estimate. We then refined the result using a projected gradient descent (PGD) method that works directly with the sample's refractive index. Comparing these results with radiation adaptive grid Eulerian (xRAGE) radiation hydrodynamic simulations enables identification of model validation needs or improvements. By calculating phase maps in situ, it becomes possible to reconstruct areal density maps, improving understanding of laser-capsule interactions and advancing IFE research.
Achieving practical inertial fusion energy (IFE) requires the development of target designs with well-characterized microstructure and compression response. We measured shock dynamics in low-density (17.5–500 mg/cm3) aerogel and two-photon polymerization (TPP) foams using x-ray phase contrast imaging (XPCI) methods and the Velocity Interferometer System for Any Reflector. By analyzing shock front evolution, we examined how target type and density influence shock propagation and energy dissipation. Talbot-XPCI shows that aerogels support a smooth, bowed shock front due to their homogeneous nanometer-scale pore network. In contrast, TPP foams exhibit irregular, stepwise propagation driven by interactions with their periodic micrometer-scale lattice. Shock velocity follows a power-law relation: aerogels deviate from classical scaling due to pore-collapse dissipation, while TPP foams follow the trend with larger uncertainties from density variations. Comparisons with xRAGE simulations reveal systematic underestimation of shock speeds. These results provide the first experimental constraints on shock propagation in TPP foams over a wide density range and highlight the influence of internal structure on anisotropic shock behavior. Our findings support improved benchmarking of EOS and hydrodynamic models and inform the design of foam architectures that promote implosion symmetry in IFE capsules.
Bacterial infections continue to drive the need for more effective and rapid methods for bacterial analysis. To address this, magnetic nanoparticles (MNPs) have emerged as promising tools, especially when their surfaces are modified with bacteria binders. The bis-zinc–dipicolylamine (Zn–DPA) complex is known for its broad affinity to bacteria. We have synthesized MNPs via a thermal decomposition method, encapsulated them in silica, modified their surface with Zn–DPA, and tested their ability to remove bacteria. The MNPs retain their superparamagnetic properties and crystallite structure after being encapsulated. The MNPs coated with silica and Zn–DPA effectively bind and remove both Gram-positive and Gram-negative bacteria from bacterial suspensions in both PBS buffer and red blood cell suspension. The capture efficiency (CE) of bacteria is high, >0.95 for both concentrated (1 × 108 CFU) and dilute (1 × 103 CFU) suspensions of Gram-positive and Gram-negative bacteria in PBS. The bacterial capture efficiency in red blood cell suspension with 50% hematocrit ranges is high (CE > 0.95) for both concentrated and dilute suspensions of S. aureus but lower for concentrated (CE = 0.30) and dilute (CE = 0.15) suspensions of E. coli. The Zn–DPA coated MNPs have promising binding efficiencies for a broad-spectrum of bacteria within a short period of time, potentially leading to applications in diagnostic devices for both medical and industrial uses.
We present ground-based multiband light curves of the AGN Mrk 509, NGC 4151, and NGC 4593 obtained contemporaneously with Swift monitoring. We measure cross-correlation lags relative to Swift UVW2 (1928 Å) and test the standard prediction for disc reprocessing, which assumes a geometrically thin optically thick accretion disc where continuum interband delays follow the relation . For Mrk 509 the 273-d Swift campaign gives well-defined lags that increase with wavelength as , steeper than the thin-disc prediction, and the optical lags are a factor of longer than expected for a simple disc-reprocessing model. This ‘disc-size discrepancy’ as well as excess lags in the u and r bands (which include the Balmer continuum and H , respectively) suggest a mix of short lags from the disc and longer lags from nebular continuum originating in the broad-line region. The shorter Swift campaigns, 69 d on NGC 4151 and 22 d on NGC 4593, yield less well-defined shorter lags d. The NGC 4593 lags are consistent with but with uncertainties too large for a strong test. For NGC 4151 the Swift lags match , with a small U-band excess, but the ground-based lags in the r, i, and z bands are significantly shorter than the B and g lags, and also shorter than expected from the thin-disc prediction. The interpretation of this unusual lag spectrum is unclear. Overall these results indicate significant diversity in the relation across the optical/UV/NIR, which differs from the more homogeneous behaviour seen in the Swift bands.