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1. Analysis identifying minimal governing parameters for clinically accurate in silico fractional flow reserve

   https://doi.org/10.3389/fmedt.2022.1034801  

   Tanade, Cyrus; Chen, S James; Leopold, Jane A; Randles, Amanda (December 2022, Frontiers in Medical Technology)

   BackgroundPersonalized hemodynamic models can accurately compute fractional flow reserve (FFR) from coronary angiograms and clinical measurements (FFR ${}_{\mathrm{baseline}}$), but obtaining patient-specific data could be challenging and sometimes not feasible. Understanding which measurements need to be patient-tuned vs. patient-generalized would inform models with minimal inputs that could expedite data collection and simulation pipelines. AimsTo determine the minimum set of patient-specific inputs to compute FFR using invasive measurement of FFR (FFR ${}_{\mathrm{invasive}}$) as gold standard. Materials and MethodsPersonalized coronary geometries ( $N=50$) were derived from patient coronary angiograms. A computational fluid dynamics framework, FFR ${}_{\mathrm{baseline}}$, was parameterized with patient-specific inputs: coronary geometry, stenosis geometry, mean arterial pressure, cardiac output, heart rate, hematocrit, and distal pressure location. FFR ${}_{\mathrm{baseline}}$was validated against FFR ${}_{\mathrm{invasive}}$and used as the baseline to elucidate the impact of uncertainty on personalized inputs through global uncertainty analysis. FFR ${}_{\mathrm{streamlined}}$was created by only incorporating the most sensitive inputs and FFR ${}_{\text{semi-streamlined}}$additionally included patient-specific distal location. ResultsFFR ${}_{\mathrm{baseline}}$was validated against FFR ${}_{\mathrm{invasive}}$via correlation ( $r=0.714$, $p<0.001$), agreement (mean difference: $0.01\pm 0.09$), and diagnostic performance (sensitivity: 89.5%, specificity: 93.6%, PPV: 89.5%, NPV: 93.6%, AUC: 0.95). FFR ${}_{\text{semi-streamlined}}$provided identical diagnostic performance with FFR ${}_{\mathrm{baseline}}$. Compared to FFR ${}_{\mathrm{baseline}}$vs. FFR ${}_{\mathrm{invasive}}$, FFR ${}_{\mathrm{streamlined}}$vs. FFR ${}_{\mathrm{invasive}}$had decreased correlation ( $r=0.64$, $p<0.001$), improved agreement (mean difference: $0.01\pm 0.08$), and comparable diagnostic performance (sensitivity: 79.0%, specificity: 90.3%, PPV: 83.3%, NPV: 87.5%, AUC: 0.90). ConclusionStreamlined models could match the diagnostic performance of the baseline with a full gamut of patient-specific measurements. Capturing coronary hemodynamics depended most on accurate geometry reconstruction and cardiac output measurement. 

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2. Ultrasensitive multispecies spectroscopic breath analysis for real-time health monitoring and diagnostics

   https://doi.org/10.1073/pnas.2105063118  

   Liang, Qizhong; Chan, Ya-Chu; Changala, P. Bryan; Nesbitt, David J.; Ye, Jun; Toscano, Jutta (October 2021, Proceedings of the National Academy of Sciences)

   Breath analysis enables rapid, noninvasive diagnostics, as well as long-term monitoring of human health, through the identification and quantification of exhaled biomarkers. Here, we demonstrate the remarkable capabilities of mid-infrared (mid-IR) cavity-enhanced direct-frequency comb spectroscopy (CE-DFCS) applied to breath analysis. We simultaneously detect and monitor as a function of time four breath biomarkers— ${\mathrm{C}\mathrm{H}}_3$OH, ${\mathrm{C}\mathrm{H}}_4$, ${\mathrm{H}}_2$O, and HDO—as well as illustrate the feasibility of detecting at least six more ( ${\mathrm{H}}_2$CO, ${\mathrm{C}}_2{\mathrm{H}}_6$, OCS, ${\mathrm{C}}_2{\mathrm{H}}_4$, ${\mathrm{C}\mathrm{S}}_2$, and ${\mathrm{N}\mathrm{H}}_3$) without modifications to the experimental apparatus. We achieve ultrahigh detection sensitivity at the parts-per-trillion level. This is made possible by the combination of the broadband spectral coverage of a frequency comb, the high spectral resolution afforded by the individual comb teeth, and the sensitivity enhancement resulting from a high-finesse cavity. Exploiting recent advances in frequency comb, optical coating, and photodetector technologies, we can access a large variety of biomarkers with strong carbon–hydrogen-bond spectral signatures in the mid-IR. 

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3. Spin stiffness and spin excitation gap of van der Waals ferromagnetic ${\mathrm{Fe}}_{3+\delta }{\mathrm{GeTe}}_2$

   https://doi.org/10.1088/1361-648X/ad581f  

   Shu, Zhixue; Zhang, Shufeng; Kong, Tai (June 2024, Journal of Physics: Condensed Matter)

   Abstract ${\mathrm{Fe}}_{3+\delta }{\mathrm{GeTe}}_2$(FGT) has proved to be an interesting van der Waals (vdW) ferromagnetic compound with a tunable Curie temperature ( $T_{\mathrm{C}}$). However, the underlying mechanism for varying $T_{\mathrm{C}}$remains elusive. Here, we systematically investigate and compare low-temperature magnetic properties of single crystalline FGT samples that exhibit $T_{\mathrm{C}}$s ranging from 160 K to 205 K. Spin stiffness (D) and spin excitation gap (Δ) are extracted using Bloch’s theory for crystals with varying Fe content. Compared to Cr-based vdW ferromagnets, FGT compounds have higher spin stiffness values but lower spin wave excitation gaps. We discuss the implication of these relationships in Fe–Fe ion magnetic interactions in FGT unit cells. The itinerancy of magnetic electrons is measured and discussed under the Rhodes–Wohlfarth ratio (RWR) and the Takahashi theory. 

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4. High Pressure Synthesis of Rubidium Superhydrides

   https://doi.org/10.1103/PhysRevLett.134.196102  

   Kuzovnikov, Mikhail A; Wang, Busheng; Wang, Xiaoyu; Marqueño, Tomas; Shuttleworth, Hannah A; Strain, Calum; Gregoryanz, Eugene; Zurek, Eva; Peña-Alvarez, Miriam; Howie, Ross T (May 2025, Physical Review Letters)

   Through laser-heated diamond anvil cell experiments, we synthesize a series of rubidium superhydrides and explore their properties with synchrotron x-ray powder diffraction and Raman spectroscopy measurements, combined with density functional theory calculations. Upon heating rubidium monohydride embedded in ${\mathrm{H}}_2$at a pressure of 18 GPa, we form ${\mathrm{RbH}}_9\text{−}\mathrm{I}$, which is stable upon decompression down to 8.7 GPa, the lowest stability pressure of any known superhydride. At 22 GPa, another polymorph, ${\mathrm{RbH}}_9\text{−}\mathrm{II}$is synthesised at high temperature. Unique to the Rb-H system among binary metal hydrides is that further compression does not promote the formation of polyhydrides with higher hydrogen content. Instead, heating above 87 GPa yields ${\mathrm{RbH}}_5$, which exhibits two polymorphs ( ${\mathrm{RbH}}_5\text{−}\mathrm{I}$and ${\mathrm{RbH}}_5\text{−}\mathrm{II}$). All of the crystal structures comprise a complex network of quasimolecular ${\mathrm{H}}_2$units and ${\mathrm{H}}^{-}$anions, with ${\mathrm{RbH}}_5$providing the first experimental evidence of linear ${\mathrm{H}}_3^{-}$anions. Published by the American Physical Society2025 

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5. Growth and characterization of Sc ₂ O ₃ doped Ta ₂ O ₅ thin films

   https://doi.org/10.1364/AO.59.00A106  

   Fazio, Mariana; Yang, Le; Markosyan, Ashot; Bassiri, Riccardo; Fejer, Martin_M; Menoni, Carmen_S (December 2019, Applied Optics)

   We present the optical and structural characterization of films of ${\mathrm{T}\mathrm{a}}_2{\mathrm{O}}_5$, ${\mathrm{S}\mathrm{c}}_2{\mathrm{O}}_3$, and ${\mathrm{S}\mathrm{c}}_2{\mathrm{O}}_3$doped ${\mathrm{T}\mathrm{a}}_2{\mathrm{O}}_5$with a cation ratio around 0.1 grown by reactive sputtering. The addition of ${\mathrm{S}\mathrm{c}}_2{\mathrm{O}}_3$as a dopant induces the formation of tantalum suboxide due to the “oxygen getter” property of scandium. The presence of tantalum suboxide greatly affects the optical properties of the coating, resulting in higher absorption loss at $\mathrm{\lambda <\#comment/>}=1064\mathrm{n}\mathrm{m}$. The refractive index and optical band gap of the mixed film do not correspond to those of a mixture of ${\mathrm{T}\mathrm{a}}_2{\mathrm{O}}_5$and ${\mathrm{S}\mathrm{c}}_2{\mathrm{O}}_3$, given the profound structural modifications induced by the dopant. 

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