We have studied the deflection of ground-state sodium atoms passing through a micron-sized parallel-plate cavity by measuring the intensity of a sodium atomic beam transmitted through the cavity as a function of cavity plate separation. This experiment provides clear evidence for the existence of the Casimir-Polder force, which is due to modification of the ground-state Lamb shift in the confined space of a cavity. Our results confirm the magnitude of the force and the distance dependence predicted by quantum electrodynamics. PACS numbers: 42.50.Wm, 32.70Jz, 42.50.Lc Physicists have long been intrigued by the idea that the electromagnetic vacuum interacts with charged particles to produce observable effects. The first experimental verification of this idea was the discovery [1] that the 251/2 and 2P\/2 states of hydrogen are not degenerate. Crudely speaking, the degeneracy is split by the ac Stark effect due to the interaction with the vacuum. Energy shifts of this type are now well established and are generally known as Lamb shifts. The vacuum field in the vicinity of a conducting plate is different from that of free space. In particular, at a distance L from the plate, the spatial distribution, polarization, and spectral density of the vacuum field are substantially altered for frequencies below ~~c/L because of the boundary conditions imposed by the plate. The first discussion of a physical effect due to this modification of the vacuum dates back to 1948 and the seminal work of Casimir [2]. Casimir and Polder [3] discussed the interaction of a neutral atom with a plane conducting plate and showed that the modified vacuum gives rise to a spatially varying Lamb shift whose gradient corresponds to an attractive long-range force. Similar long-range forces are found between any pair of neutral objects, the most famous example being perhaps the Casimir force between two conducting plates. We refer to any such force on an isolated atom as a Casimir-Polder force.Although some quantitative measurements exist on the long-range forces between macroscopic dielectrics [4], the Casimir force has been studied only qualitatively [5], and the Casimir-Polder interaction has eluded detection altogether [6]. Recent experiments on the Rydberg states of helium [7] have yielded precise measurements of the long-range interaction between the Rydberg electron and the He + core, but have not yet reached the point of testing the Casimir-Polder interaction [8], known in that system as K r 'et. In the experiment reported here we have probed the vacuum field in a parallel-plate cavity using a beam of ground-state sodium atoms. Since the vacuum field varies with position, the atoms experience a Casimir-Polder force which pushes them towards the cavity walls. We have used the deflection of the beam to demonstrate the existence of this force and to confirm quantitatively the strength predicted by quantum electrodynamics.For a spherical ground-state atom (3s sodium) between parallel ideal mirrors, the position-dependent atom-cavity interacti...
Background: Probody™ therapeutics are novel, fully recombinant antibody prodrugs designed to remain relatively inactive in healthy tissue and to be specifically activated by proteases in the tumor microenvironment. In this way, Probody therapeutics may broaden the therapeutic window for effective but potentially toxic anticancer agents. CX-072 is a Probody therapeutic directed against programmed death-ligand 1 (PD-L1) for the treatment of cancer patients. In a first-in-human, open-label, multicenter, dose-escalation, 3+3 design, phase 1-2 study, PROCLAIM-CX-072 (PRObody CLinical Assessment In Man) (NCT03013491), 22 patients were enrolled in the phase 1 dose escalation portion. Twenty patients were evaluable per RECIST v1.1. Three patients had confirmed partial response (15%), including a 39-year-old woman with stage IV triple negative breast cancer (TNBC) treated with 10 mg/kg CX-072 monotherapy whose disease had progressed on one previous line of chemotherapy for metastatic disease. Metastatic sites included extensive nodal disease and skin/chest wall lesions. The tumor was negative for PD-L1 expression, was microsatellite stable, and had a low tumor mutational burden (4 mutations/megabase). Positive results from the phase 1 study suggest that additional exploration of treatment with CX-072 monotherapy in the TNBC patient population is warranted. Dose expansion trial design: The phase 2 dose expansion part of the PROCLAIM-CX-072 study will include enrollment of TNBC patients with skin metastases. Key inclusion criteria for patients in the TNBC cohort are as follows: naive to immunotherapy (PD-1/PD-L1 and CTLA-4 inhibitors), approved immune checkpoint inhibitor agents not available, histologically confirmed triple negative (estrogen receptor–, progesterone receptor–, and human epidermal growth factor receptor-2–negative cancer per ASCO-CAP guidelines), previously treated with 1 to 3 systemic chemotherapy regimens, and locally advanced and recurrent skin or subcutaneous metastases not suitable for surgical resection or radiotherapy. Patients will receive doses of 10 mg/kg CX-072 intravenously every 2 weeks. Efficacy will be evaluated using RECIST v1.1 and immune-related RECIST criteria. Safety and tolerability will be assessed based on the incidence and severity of adverse events (categorized by NCI CTCAE criteria, v4.03) and relationship to study drug. Other analyses will include pharmacokinetics, incidence of anti-drug antibodies against CX-072, exploratory analysis for immune response, and CX-072 activation in the tumor. PROBODY is a trademark of CytomX Therapeutics, Inc. Citation Format: Adams S, Hamilton E, Ott PA, Cho D, Kalinsky K, LoRusso P, Will M, Huels V, Benson B, Murias C, Arkenau H-T. PROCLAIM-CX-072: Monotherapy for advanced triple negative breast cancer with skin metastases in a phase 1-2 trial of the PD-L1 probody therapeutic CX-072 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-31.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.