Electronic Raman scattering in the 2D antiferromagnet NiPS3.

Correlated-electron systems have long been an important platform for various interesting phenomena and fundamental questions in condensed matter physics. As a pivotal process in these systems, d-d transitions have been suggested as a key factor toward realizing optical spin control in two-dimensional (2D) magnets. However, it remains unclear how d-d excitations behave in quasi-2D systems with strong electronic correlation and spin-charge coupling. Here, we present a systematic electronic Raman spectroscopy investigation on d-d transitions in a 2D antiferromagnet­NiPS3, from bulk to atomically thin samples. Two electronic Raman modes originating from the scattering of incident photons with d electrons in Ni2+ ions are observed at ~1.0 eV. This electronic process persists down to trilayer flakes and exhibits insensitivity to the spin ordering of NiPS3. Our study demonstrates the utility of electronic Raman scattering in investigating the unique electronic structure and its coupling to magnetism in correlated 2D magnets.

Spin-induced linear polarization of photoluminescence in antiferromagnetic van der Waals crystals.

Antiferromagnets are promising components for spintronics due to their terahertz resonance, multilevel states and absence of stray fields. However, the zero net magnetic moment of antiferromagnets makes the detection of the antiferromagnetic order and the investigation of fundamental spin properties notoriously difficult. Here, we report an optical detection of Néel vector orientation through an ultra-sharp photoluminescence in the van der Waals antiferromagnet NiPS3 from bulk to atomically thin flakes. The strong correlation between spin flipping and electric dipole oscillator results in a linear polarization of the sharp emission, which aligns perpendicular to the spin orientation in the crystal. By applying an in-plane magnetic field, we achieve manipulation of the photoluminescence polarization. This correlation between emitted photons and spins in layered magnets provides routes for investigating magneto-optics in two-dimensional materials, and hence opens a path for developing opto-spintronic devices and antiferromagnet-based quantum information technologies.

Vascular endothelial growth factor in bipolar depression: A potential biomarker for diagnosis and treatment outcome prediction.

BACKGROUND: Vascular Endothelial Growth Factor (VEGF) has been implicated in the neurotrophic model of depression. We explored the potential role of VEGF in the pathophysiology of bipolar depression and potential utility as a diagnostic or outcome predictive biomarker. METHODS: In a double-blind study, treatment-resistant bipolar depressed patients received Escitalopram and were randomized to receive add-on Celecoxib (26 participants) or Placebo (21 participants). There were 32 healthy controls. Plasma levels of VEGF were determined at three timepoints over eight weeks. RESULTS: Bipolar patients had significantly higher VEGF levels at baseline compared to healthy controls. Logistic regression analysis revealed that the AUC is 0.67 and the VEGF cut point is 8.21. At all timepoints, patients receiving Celecoxib had comparable VEGF levels to those receiving Placebo. VEGF levels did not change significantly over time. Baseline VEGF was a poor predictor of treatment response with an AUC of 0.53. CONCLUSIONS: The increased VEGF in bipolar depression agrees with similar findings in major depressive disorder. A high VEGF level tended to accurately predict bipolar disorder, with apparent differential VEGF expression. Baseline VEGF did not predict treatment response, and levels did not change with treatment. Plasma VEGF may have diagnostic utility and guide personalized treatment.

Efficacy of a reverse-phase polymer as a submucosal injection solution for EMR: a comparative study (with video).

INTRODUCTION: Reverse-phase polymers undergo a temperature-dependent liquid-to-gel transition that may provide a more durable cushion for EMR and could yield improvements in safety and efficacy. OBJECTIVE: Our purpose was to assess the efficacy of poloxamer solution PS137-25 as a submucosal injection. DESIGN: Comparative study among 3 different solutions for EMR using ex vivo and in vivo porcine models. INTERVENTIONS: A total of 120 gastric submucosal cushions were performed in fresh ex vivo porcine stomachs with saline solution 0.9% (n = 40), hydroxypropyl methylcellulose (HPMC) (n = 40), and PS137-25 (n = 40). Five in vivo porcine colon EMRs were then performed. MAIN OUTCOME MEASUREMENTS: Height and duration of submucosal cushions were measured in the ex vivo model, and the usefulness of reverse-phase polymers was assessed by in vivo en bloc resection. RESULTS: Ex vivo: The height of mucosal elevation was greater with PS137-25 (10.3 +/- 2.2 mm) than with saline solution (8.3 +/- 2.6 mm) or HPMC (9.05 +/- 2.3 mm, not significant). All submucosal elevations with PS137-25 lasted longer (more than 20 minutes) than with saline solution (20.9 +/- 11 minutes, P < .01) or HPMC (89 +/- 32 minutes, P < .01). After 120 minutes, the elevations obtained with PS137-25 showed no differences in size, shape, or consistency from initial measurements. In vivo: All 5 EMRs were successfully performed after 1 injection of PS137-25. No repeat injections were needed. During resection, a large gel cushion was noted. CONCLUSIONS: Mucosal elevation with PS137-25 is more durable than with other substances, with no changes in size or consistency observed over 120 minutes. Additionally, reverse-phase polymers performed well in in vivo colon EMRs. These results suggest that reverse-phase polymers may provide increased safety and efficacy for EMR procedures.