Modular thermal Hall effect measurement setup for fast-turnaround screening of materials over wide temperature range using capacitive thermometry

We demonstrate a simple and easy-to-build probe designed to be loaded into a widely available Quantum Design Physical Properties Measurement System (PPMS) cryostat, with a detachable shielded sample puck section and robust heat sinking of three pairs of coaxial cables. It can be in principle used with any low-temperature cryostat. Our modular puck design has a radiation shield for thermal isolation and protection of the delicate sample space while handling and allows any variety of experimental setup benefiting from shielded coaxial wiring to be constructed on a selection of sample pucks. Pucks can be quickly and easily switched, and the system makes use of the simple yet extremely stable temperature and magnetic field control of the easy-to-use PPMS system. We focus on a setup designed for measurements of the thermal Hall effect and show that this system can yield unprecedented resolution over a wide temperature range and with rapid sample mounting or changing—allowing a large collection of potential samples to be screened for this novel physics. Our design aims to make these sensitive but challenging measurements quick, reliable, cheap, and accessible, through the use of a standard, widespread base cryostat and a system of modular removable sample stage pucks to allow quick turnaround and screening of a large number of candidate samples for potential new thermal Hall physics

Controlling the near-surface superfluid density in underdoped YBa₂Cu₃O_6+<i>x</i> by photo-illumination

The interaction with light weakens the superconducting ground state in classical superconductors. The situation in cuprate superconductors is more complicated: illumination increases the charge carrier density, a photo-induced effect that persists below room temperature. Furthermore, systematic investigations in underdoped YBa₂Cu₃O6+x (YBCO) have shown an enhanced critical temperature Tc. Until now, studies of photo-persistent conductivity (PPC) have been limited to investigations of structural and transport properties, as well as the onset of superconductivity. Here we show how changes in the magnetic screening profile of YBCO in the Meissner state due to PPC can be determined on a nanometer scale utilizing low-energy muons. The data obtained reveal a strongly increased superfluid density within the first few tens of nanometers from the sample surface. Our findings suggest a non-trivial modification of the near-surface band structure and give direct evidence that the superfluid density of YBCO can be controlled by light illumination

Photodynamic Priming Mitigates Chemotherapeutic Selection Pressures and Improves Drug Delivery

Physiological barriers to drug delivery and selection for drug resistance limit survival outcomes in cancer patients. In this study, we present preclinical evidence that a subtumoricidal photodynamic priming (PDP) strategy can relieve drug delivery barriers in the tumor microenvironment to safely widen the therapeutic window of a nanoformulated cytotoxic drug. In orthotopic xenograft models of pancreatic cancer, combining PDP with nanoliposomal irinotecan (nal-IRI) prevented tumor relapse, reduce metastasis and increase both progression-free survival and 1-year disease-free survival. PDP enabled these durable improvements by targeting multiple tumor compartments to (1) increase intratumoral drug accumulation by >10-fold, (2) increase the duration of drug exposure above a critical therapeutic threshold, and (3) attenuate surges in CD44 and CXCR4 expression which mediate chemoresistance often observed after multi-cycle chemotherapy. Overall, our results offer preclinical proof of concept for the effectiveness of PDP to minimize risks of tumor relapse, progression and drug resistance and to extend patient survival

Controlling the near-surface superfluid density in underdoped YBa2Cu3O6+x by photo-illumination

The interaction with light weakens the superconducting ground state in classical superconductors. The situation in cuprate superconductors is more complicated: illumination increases the charge carrier density, a photo-induced effect that persists below room temperature. Furthermore, systematic investigations in underdoped YBa2Cu3O6+x (YBCO) have shown an enhanced critical temperature Tc. Until now, studies of photo-persistent conductivity (PPC) have been limited to investigations of structural and transport properties, as well as the onset of superconductivity. Here we show how changes in the magnetic screening profile of YBCO in the Meissner state due to PPC can be determined on a nanometer scale utilizing low-energy muons. The data obtained reveal a strongly increased superfluid density within the first few tens of nanometers from the sample surface. Our findings suggest a non-trivial modification of the near-surface band structure and give direct evidence that the superfluid density of YBCO can be controlled by light illumination

Absolute value and temperature dependence of the magnetic penetration depth in Ba(Co0.074Fe0.926)(2)As-2

The absolute value and temperature dependence of the in-plane magnetic penetration depth λ have been measured on a single crystal of Ba(Co0.074Fe0.926)2As2 using low-energy muon-spin rotation and microwave cavity perturbation. The magnetic field profiles in the Meissner state are consistent with a local London model beyond a depth of 15 nm. We determine the gap symmetry through measurements of the temperature dependence of the superfluid density which follows a two-gap s-wave model over the entire temperature range below Tc. While the intermediate to high temperature data is well fit by an energy gap model in the BCS-like (weak-coupling) limit, a second smaller gap becomes apparent at low temperatures

European Fantacy of the Arctic Region and the Rise of Indigenous Sámi Voices in the global Arena

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